JP7173110B2 - Optical output control unit and optical projection device - Google Patents

Description

The present invention relates to a light output control unit and a light projection device.

2. Description of the Related Art In an optical projection device that forms an image on a projection surface by projecting light, a plurality of types of semiconductor laser elements, such as red, green, and blue, are used to project light of desired colors. However, even if a drive current is applied to the semiconductor laser device, it takes a certain amount of time to generate carriers with a concentration that enables laser oscillation. As a result, light emission delay occurs, and it may take a rise time until the amount of light corresponding to the drive current is output. The light emission delay means that at the beginning of the application of the drive current, only a small amount of light is output from the semiconductor laser element, and it takes time until a constant amount of light corresponding to the current value of the applied drive current is output. This is the phenomenon. In particular, in recent years, systems using red semiconductor laser elements of 600 [nm] and green semiconductor laser elements of 500 [nm] have been put into practical use. These semiconductor laser devices tend to have rise time more than conventional semiconductor laser devices of 1.3 μm band, 1.5 μm band, or 780 nm band. This is because these semiconductor laser devices have the characteristic that it takes more time to generate carriers with a concentration that enables laser oscillation.

Therefore, for example, in Patent Document 1, the light emission delay of the semiconductor laser element is compensated for by applying an auxiliary current in addition to the drive current at the start of light emission.

JP 2012-209380 A

However, in an optical projection device having a plurality of semiconductor laser elements, the amount of rise time required differs depending on the type of semiconductor laser element. Therefore, if each semiconductor laser element has a different degree of light emission delay, the timing at which each semiconductor laser element outputs the light amount corresponding to the drive current will be shifted, and the edge portion of the image displayed on the projection surface will be colored. Unevenness occurs. For example, among a plurality of types of semiconductor laser devices, the red and green semiconductor laser devices tend to cause light emission delays. Therefore, when a pure white image is projected by emitting light from each semiconductor laser element at the same time, the blue semiconductor laser element does not emit light with a delay. it becomes a color.

With respect to such a problem, Patent Document 1 does not mention anything about compensating for the light emission delays of a plurality of types of semiconductor laser elements with different degrees. In addition, in Patent Document 1, since the auxiliary current is added to the drive current at the start of light emission, the amount of light tends to overshoot, making it difficult to adjust the amount of light at the start of light emission. Furthermore, there is also a problem that the power consumption for the auxiliary current increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light output control unit and a light projection device capable of suppressing or preventing the occurrence of problems caused by light emission delay of a light source. and

In order to achieve the above object, an optical output control unit according to one aspect of the present invention comprises an optical output control section for controlling optical outputs of a plurality of light emitting elements, wherein the light amount of the plurality of light emitting elements changes from zero to When performing a white display, the light output control unit causes the first light emitting element having the longest optical response time required to output the light amount for the white display among the plurality of light emitting elements to output the light amount for the white display. is applied to the first light emitting element earlier than the time point of applying to the second light emitting element the driving current for outputting the light amount of the white display from the other second light emitting element. (first configuration).

In the light output control unit of the first configuration, the light output control section controls the light output based on the time difference in the light response time of each of the plurality of light emitting elements to control the light amount of the first light emitting element. A configuration (second configuration) may be employed in which the time point at which the light amount of the white display is reached is the same as the time point at which the light amount of the second light emitting element reaches the light amount of the white display.

In the light output control unit of the first configuration, the light output control section adjusts the light intensity of the first light emitting element to the white display light intensity based on the time difference of the light response time of each of the plurality of light emitting elements. The time point at which the amount of light from the second light emitting element reaches the predetermined ratio with respect to the white display may be the same as the time point at which the amount of light from the second light emitting element reaches the predetermined ratio with respect to the amount of light for white display (third configuration).

The optical output control unit having the third configuration may be configured such that the predetermined ratio is 50% (fourth configuration).

In the light output control unit having any one of the first to fourth configurations, the light output control section controls the light output of the first current value that causes the second light emitting element to output a light amount less than the light amount of the white display. After applying the driving current to the second light emitting element, the driving current having a second current value that causes the second light emitting element to output the light amount of the white display is applied to the second light emitting element (fifth configuration).

In the light output control unit having any one of the first to fifth configurations, the light output control section causes the drive current of the second light emitting element to output light of the light amount for white display from the second light emitting element. A configuration (sixth configuration) may be employed in which the current value is increased in a plurality of stages.

The light output control unit having any one of the above first to sixth configurations detects the light emitted from each of the plurality of light emitting elements based on the detection result of the light detection section that detects the amount of light emitted from each of the plurality of light emitting elements. A configuration (seventh configuration) that further includes a calculation unit that calculates the response time may be employed.

In the light output control unit of the seventh configuration, the light output control section causes the plurality of light emitting elements to output scanning light projected and scanned onto the projection surface to form an image on the projection surface, and When the scanning light scans an invalid projection area on the projection surface where no is formed, the light output control section causes the plurality of light emitting elements to emit light, and the calculating section causes the scanning light to scan the invalid projection area. A configuration (eighth configuration) may be employed in which the optical response time is calculated based on the detection result of the photodetector at the time.

The light output control unit having any one of the first to eighth configurations further comprises a memory for storing image information of an image formed by the light outputs of the plurality of light emitting elements, wherein the light output control section comprises: A configuration (ninth configuration) may be employed in which the image information is analyzed and the light outputs of the plurality of light emitting elements are controlled based on the analysis result.

In order to achieve the above object, a light projection device according to one aspect of the present invention includes a light output control unit having any one of the first to ninth configurations and a plurality of light emitting elements (the tenth configuration).

According to the present invention, it is possible to provide a light output control unit and a light projection device capable of suppressing or preventing the occurrence of problems caused by the light emission delay of the light source. For example, when a plurality of light emitting elements output light, it is possible to improve color unevenness of light that occurs due to differences in the occurrence of light emission delay for each light emitting element.

1 is a schematic diagram of a HUD device; FIG. 3 is a block diagram showing a configuration example of a projector unit; FIG. 4 is a graph showing optical output characteristics with respect to LD driving current; 4 is a graph showing optical output response characteristics of a red LD; 4 is a graph showing response characteristics of light output of a green LD; 4 is a graph showing optical output response characteristics of a blue LD; It is a figure which shows the scanning condition of a scanning laser beam on the projection surface of a combiner. 5 is a flowchart for explaining an example of optical output control processing of an LD according to the first embodiment; FIG. 3 is a schematic diagram showing optical output of scanning laser light when all LDs output light simultaneously; 5 is a graph showing an example of light output control of an LD according to the first embodiment; FIG. 5 is a schematic diagram showing an example of light output of scanning laser light when light output control is performed according to the first embodiment; 9 is a graph showing an example of light output control of an LD according to the second embodiment; FIG. 11 is a graph showing an example of light output control of an LD according to the third embodiment; FIG. FIG. 11 is a graph showing another example of light output control of an LD according to the third embodiment; FIG. FIG. 4 is a schematic diagram locally showing a scanning range of scanning light continuously reciprocatingly scanned; FIG. 14 is a graph showing an example of light output control of a red LD in the fourth embodiment; FIG. FIG. 11 is a diagram showing a change in light output of forward scanning light that scans from a first scanning position to a second scanning position in the fourth embodiment; FIG. 11 is a diagram showing a change in light output of scanning light in a backward pass that scans from a second scanning position to a first scanning position in the fourth embodiment; FIG. 11 is a diagram showing apparent light amount changes of scanning light between a first scanning position and a second scanning position in the fourth embodiment; FIG. 14 is a flowchart for explaining an example of optical output control processing of an LD according to the fourth embodiment; FIG. FIG. 5 is a diagram showing ideal light output changes of an LD and actual light output changes of forward and backward scanning laser beams in the case of outputting a constant amount of light; FIG. 10 is a diagram showing an ideal light output change of an LD and an actual light output change in forward and backward passes when the light output is gently raised in the rising scanning range on the first scanning position side; FIG. 10 is a diagram showing an ideal optical output change of the LD and an actual optical output change in the forward and backward passes when the optical output is gradually raised in the rising scanning range on the second scanning position side; FIG. 21 is a graph showing an example of light output control of a red LD in the fifth embodiment; FIG. FIG. 11 is a diagram showing a change in light output of forward scanning light that scans from a first scanning position to a second scanning position in the fifth embodiment; FIG. 12 is a diagram showing a change in light output of scanning light in a backward pass that scans from the second scanning position to the first scanning position in the fifth embodiment; FIG. 11 is a diagram showing apparent light amount changes of scanning light between a first scanning position and a second scanning position in the fifth embodiment; FIG. 21 is a graph showing an example of light output control of a green LD in the sixth embodiment; FIG. FIG. 12 is a diagram showing a change in light output of forward scanning light that scans from a first scanning position to a second scanning position in the sixth embodiment; FIG. 12 is a diagram showing changes in light output of scanning light in a backward pass that scans from the second scanning position to the first scanning position in the sixth embodiment; FIG. 12 is a diagram showing apparent light amount changes of scanning light between a first scanning position and a second scanning position in the sixth embodiment; 10 is a graph showing optical output characteristics with respect to driving current of a red LD; FIG. 21 is a graph showing an example of light output control of a red LD in the seventh embodiment; FIG. FIG. 14 is a diagram showing a change in light output of forward scanning light that scans from a first scanning position to a second scanning position in the seventh embodiment; FIG. 20 is a diagram showing a change in optical output of scanning light in a backward pass that scans from the second scanning position to the first scanning position in the seventh embodiment; FIG. 21 is a diagram showing apparent light amount changes of scanning light between a first scanning position and a second scanning position in the seventh embodiment; FIG. 16 is a flowchart for explaining an example of optical output control processing of an LD according to the seventh embodiment; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking a head-up display device 100 for a vehicle as an example. Note that the head-up display device 100 is hereinafter referred to as a HUD (Head-Up Display) device 100 .

<First embodiment>
FIG. 1 is a schematic diagram of a HUD device 100. As shown in FIG. A HUD device 100 of this embodiment is mounted on a vehicle 200 . The HUD device 100 is a display device that projects a scanning laser beam 300 (scanning light) from a projector unit 101 (light projection device) toward a combiner 102 and displays the projected image superimposed within the user's field of view. Note that in FIG. 1 , the dashed-dotted arrow 400 indicates the line of sight of the user sitting in the driver's seat of the vehicle 200 . Moreover, the HUD device 100 may be mounted not only on a vehicle but also on another vehicle (for example, an aircraft).

The combiner 102 is attached to the inner surface of the windshield 201 of the vehicle 200 as shown in FIG. The combiner 102 is a projection member for displaying the projected image of the projector unit 101 within the field of view of the user, and is formed using a semi-transmissive reflective material such as a half mirror. A virtual image (picture) is formed on a predetermined area of the projection surface 102 a of the combiner 102 by projecting the scanning laser beam 300 from the projector unit 101 onto the combiner 102 . Therefore, a user looking in front of vehicle 200 (that is, in the direction of line of sight 400) can simultaneously view the external image in front of vehicle 200 and the projected image projected from projector unit 101. FIG.

Next, the projector unit 101 will be explained. FIG. 2 is a block diagram showing a configuration example of the projector unit 101. As shown in FIG. As shown in FIG. 2, the projector unit 101 includes a housing 1, an optical engine section 2, and a MEMS engine section 3 in the first embodiment.

A housing 1 carries an optical engine section 2 and a MEMS engine section 3 . Further, the housing 1 is formed with a window portion 1a (light transmission window) for emitting the scanning laser beam 300 emitted from the MEMS engine portion 3 to the outside. The window portion 1a is formed using, for example, glass or a translucent resin material. A more detailed configuration of the housing 1 will be described later.

The optical engine section 2 includes a plurality of laser diodes 21a to 21c, an optical system 22, and photodetectors 23a to 23c, and emits light to the MEMS engine section 3. FIG. In the following, the laser diodes 21a to 21c are called LDs (Laser Diodes) 21a to 21c, respectively, and the photodetectors 23a to 23c are called PDs (Photo Detectors) 23a to 23c, respectively. Note that the configuration of the optical engine section 2 is not limited to the example shown in FIG. For example, instead of the photodetectors 23a to 23c, the optical engine section 2 includes a half mirror (for example, a transmittance of 99%) arranged between the optical system 22 and the MEMS engine section 3, and an optical output of reflected light from the half mirror. may include a PD (photodetector) that detects the

The LD 21a is a light emitting element that emits red laser light. LD21b is a light emitting element that emits a green laser beam. LD21c is a light emitting element that emits blue laser light.

Here, the optical output characteristics of the LDs 11a to 11c with respect to the drive current will be described. Here, the LD 11a will be described as an example, but since the optical output characteristics with respect to the drive current of the other LDs 11b and 11c are the same, their description will be omitted. FIG. 3 is a graph showing optical output characteristics with respect to the drive current of the LD 11a. When the optical output of the LD 11a and the driving current applied to the LD 11a fall within the colored square range Ag in FIG. Therefore, the optical output of the LD 11a becomes unstable. Also, points GA and GB on the graph are the lower and upper limits of the graph within range Ag, respectively. When the light output and drive current become less than the light output PA and current value IA corresponding to the lower limit point GA, the LD 11a emits light in the LED light emission mode. In this case, the LD 11a outputs emitted light whose wavelengths and phases are more irregular than those in the laser oscillation mode, but emits light more stable than the light emitted within the range Ag. Further, when the optical output and the driving current become larger than the optical output PB and the current value IB corresponding to the upper limit GB, the LD 11a emits light in the LD oscillation mode. In this case, the LD 11a outputs coherent light with relatively matching wavelengths and phases by stable laser oscillation.

Next, the optical response characteristics of the LDs 11a-11c will be described. 4A to 4C are graphs showing response characteristics of optical outputs of the LDs 21a to 21c to which constant drive currents Ia1 to Ic1 are applied. FIG. 4A is a graph showing optical output response characteristics of the red LD 21a. FIG. 4B is a graph showing response characteristics of the light output of the green LD 21b. FIG. 4C is a graph showing the optical output response characteristics of the blue LD 21c. In FIGS. 4A to 4C, time tS indicates the time when application of the driving current is started (that is, light emission is started), and time tE indicates the time when application of the driving current is finished (that is, light emission is finished). These are the same in other figures.

As shown in FIGS. 4A to 4C, the LDs 21a to 21c have different optical output response characteristics. For example, each of the LDs 21a-21c causes a light emission delay at the start of application of the drive current. The light emission delay means that only light of low light intensity is output at the start of application of the drive current to each of the LDs 21a to 21c, and steady light intensities Pa1, Pb1, and Pc1 corresponding to the current values Ia1, Ib1, and Ic1 of the applied drive currents. This is a phenomenon in which the rise times TA, TB, and TC are required until light is output. Rise times TA, TB, and TC are optical response times from the start of light emission (start of application of the drive current) until the light output reaches the light intensities Pa1, Pb1, and Pc1 corresponding to the current values Ia1, Ib1, and Ic1 of the drive current. , and their time lengths are different for each of the LDs 21a to 21c. The response characteristics of the light outputs of the LDs 21a to 21c will be described below when the LDs 21a to 21c perform white display from a state in which the amount of light is 0 (that is, a state in which the light output is 0).

In the red LD 21a, as shown in FIG. 4A, when a constant drive current Ia1 is applied at time ta0 (=tS), it takes a rise time TA ( = ta1-ta0). That is, the light output of the red LD 21a gradually increases from time ta0, becomes 0.5 Pa1, which is half the steady light amount, at time ta2, and reaches the steady light amount Pa1 at time ta1. Note that the constant light amount Pa1 is, for example, the light amount Pa1 of the LD 21a when the LDs 21a to 21c perform white display. Thus, the red LD 21a is the light-emitting element that has the longest rise time TA required for outputting light with the constant light amount Pa1 from the state where the light amount is 0 among the LDs 21a to 21c.

In addition, as shown in FIG. 4B, in the green LD 21b, when a constant drive current Ib1 is applied at time tb0 (=tS), the rise time is TB (=tb1-tb0) is required. That is, the light output of the green LD 21a increases from time tb0, becomes half the constant light amount 0.5Pb1 at time tb2, and reaches the steady light amount Pb1 at time tb1. Note that the constant light amount Pb1 is, for example, the light amount Pb1 of the LD 21b when the LDs 21a to 21c perform white display. However, the rise time TB of the green LD 21b is earlier than the rise time TA of the red LD 21a (0<TB<TA).

On the other hand, the blue LD 21c has very good optical output response characteristics as shown in FIG. It emits light with a steady light amount Pc1. That is, the blue LD 21c requires almost no rise time TC (TC≈0). Note that the constant light amount Pc1 is, for example, the light amount Pc1 of the LD 21c when the LDs 21a to 21c perform white display.

Next, returning to FIG. 2, the optical engine section 2 will be described. The optical system 12 includes collimator lenses 221 a to 221 c, beam splitters 222 a to 222 c, and a condenser lens 223 . The collimator lenses 221a-221c are optical elements that convert the laser beams emitted from the LDs 21a-21c into parallel beams. The beam splitters 222a to 222c are optical elements such as dichroic mirrors, which reflect light of specific wavelengths and transmit light of other wavelengths. Further, the beam splitters 222a-222c respectively reflect part of the light incident from the collimator lenses 221a-221c and transmit the remaining part. The PDs 23a-23c are photodetectors that detect the optical output of the light incident from the beam splitters 222a-222c, respectively, and output photodetection signals based on the detection results to the CPU 58, which will be described later.

The red laser light emitted from the LD 21a is converted into parallel light by the collimator lens 221a. A portion of the red laser light is reflected by the beam splitter 222 a and passes through the beam splitter 222 c to reach the condenser lens 223 . The remaining portion of the red laser light passes through the beam splitter 222a and enters the PD 23a. Also, the green laser light emitted from the LD 21b is converted into parallel light by the collimator lens 221b. A part of the green laser light is reflected by the beam splitter 222b, passes through the beam splitters 222a and 222c, and reaches the condenser lens 223. The remaining part of the green laser light is transmitted through the beam splitter 222b and enters the PD 23b. Also, the blue laser light emitted from the LD 21c is converted into parallel light by the collimator lens 221c. Part of the blue laser light is reflected by the beam splitter 222 c and reaches the condenser lens 223 . The remaining portion of the blue laser light passes through the beam splitter 222c and enters the PD 23c. The condensing lens 223 converges the laser beams incident from the LDs 21a to 21c through the collimator lenses 221a to 221c and the beam splitters 222a to 222c onto the light reflecting surface of the MEMS mirror 31 .

The MEMS engine unit 3 includes a MEMS mirror 31, and oscillates the scanning laser beam 300 projected from the LDs 21a to 21c onto the projection surface 102a of the combiner 102 and its optical axis to scan the projection surface 102a. A scanning optical unit. The MEMS mirror 31 is an optical reflection element that reflects the laser light converged by the condenser lens 223 . The MEMS mirror 31 reflects each laser beam as scanning laser beam 300 . The scanning laser beam 300 passes through the window portion 1 a of the housing 1 and a light exit port 50 a which will be described later, is emitted to the outside of the projector unit 101 , and is projected onto the projection surface 102 a on the combiner 102 . Further, the MEMS mirror 31 is driven to swing in two axial directions to change the optical axis of the scanning laser beam 300, thereby scanning the projection surface 102a with the scanning laser beam 300. FIG. In this manner, the MEMS mirror 31 scans the scanning laser beam 300 projected onto the projection surface 102a by swinging the optical axis of the scanning laser beam 300 in the horizontal and vertical directions of the combiner 102 .

FIG. 5 is a diagram showing the scanning state of the scanning laser beam 300 and its optical axis on the projection surface 102a of the combiner 102. As shown in FIG. Hereinafter, in the projection surface 102a, the horizontal direction toward the right side of the projection surface 102a may be called the X direction, and the vertical direction toward the lower side of the projection surface 102a may be called the Y direction. These are the same in other figures.

The scanning laser beam 300 is reciprocally scanned in the horizontal direction X over a range in the vertical direction Y as shown in FIG. That is, the optical axis of the scanning laser beam 300 alternately performs reciprocating zigzag scanning in the Y direction and reciprocating zigzag scanning in the −Y direction. In addition, hereinafter, reciprocating scanning of zigzags in the Y direction from the uppermost side to the lowermost side in FIG. 5 will be referred to as a trace. Further, zigzag back-and-forth scanning in the −Y direction from the bottom to the top of FIG. 5 is called retrace.

In a trace, an image is formed on the projection surface 102a by a group of scanning laser beams 300 that have a range of directions in the vertical direction Y and are scanned back and forth in the horizontal direction X. FIG. That is, this image is formed by a group of scanning laser beams 300 in which scanning in the -X direction having a predetermined Y-direction component and scanning in the X direction having a predetermined Y-direction component are alternately performed. In the following description, the scanning laser beam 300 having a predetermined Y direction component and scanned in the -X direction will be referred to as forward scanning laser beam 300a. Further, the scanning laser beam 300 that has a predetermined Y-direction component and is scanned in the X direction is referred to as a backward scanning laser beam 300b. The predetermined Y-direction component of each scanning laser beam 300a, 300b is determined according to the Y-direction scanning pitch (that is, scanning interval) of each scanning laser beam 300a, 300b.

In FIG. 5, the area surrounded by the dashed line on the projection surface 102a is the effective projection area 102b. Moreover, the area other than the projection area 102b is an invalid projection area 102c. The effective projection area 102b is an area in which an image can be formed by the scanning laser light 300 during the trace period. Note that no image is formed during the retrace period. In addition, the invalid projection area 102c is an area where no image is formed during the trace period and the retrace period. In this region 102c, the optical axis of the scanning laser beam 300 is scanned, but the scanning laser beam 300 itself for forming an image is not projected.

Next, returning to FIG. 2, a further configuration of the projector unit 101 will be described. The projector unit 101 further includes a main housing 50, a MEMS mirror driver 51, an LD driver 52, a power source 53, a power control section 54, an operation section 55, an input/output I/F 56, a storage section 57, A CPU 58 is provided.

A main housing 50 has a housing 1 , a MEMS mirror driver 51 , an LD driver 52 , a power supply 53 , a power control section 54 , an operation section 55 , an input/output I/F 56 , a storage section 57 and a CPU 58 . Further, the main housing 50 is formed with a light exit port 50a. The scanning laser beam 300 that has passed through the window portion 1a of the housing 1 from the MEMS engine portion 3 is further emitted to the combiner 102 through the light emitting port 50a. Although the light exit port 50a may be an opening, it is preferably formed using glass or a translucent resin material, for example. By doing so, it is possible to prevent dust and moisture (for example, water droplets and moisture-containing air) from entering the main body housing 50 .

The MEMS mirror driver 51 is a drive control unit that controls driving of the MEMS mirror 31 based on control signals input from the CPU 58 . For example, the MEMS mirror driver 51 oscillates the MEMS mirror 31 according to a horizontal synchronization signal from the CPU 58, and deflects the reflection direction of the laser light by the MEMS mirror 31 in the horizontal direction of the projection surface 102a. Further, the MEMS mirror driver 51 oscillates the MEMS mirror 31 according to a vertical synchronization signal from the CPU 58, and deflects the reflection direction of the laser beam by the MEMS mirror 31 in the vertical direction of the projection surface 102a.

The LD driver 52 is a light source driving section that supplies a drive current to each of the LDs 21a to 21c, and controls driving of light emission and light output of each of the LDs 21a to 21c. The LD driver 52 is a part of the optical output control unit, and supplies a driving current equal to or higher than the oscillation threshold current value (eg, the current value IB on the right 3) to the LDs 21a to 21c to output laser light. Power source 53 is a power supply unit that receives power supply from a power source such as a storage battery (not shown) of vehicle 200 , for example. The power supply control unit 54 converts the power supplied from the power supply 53 into a predetermined voltage value and current value corresponding to each component of the projector unit 101, and supplies the converted power to each component. The operation unit 55 is an input unit that receives a user's operation input. The input/output I/F 56 is a communication interface for wired or wireless communication with an external device.

The storage unit 57 is a non-volatile storage medium, and stores programs and control information used by each component of the projector unit 101, for example. The storage unit 57 also stores image information to be projected onto the combiner 102, operation characteristics of the LDs 21a to 21c, and information on light quantity correction (for example, response characteristics of light output, which will be described later).

The CPU 58 is a control section that controls each component of the projector unit 101 using programs and control information stored in the storage section 57 . The CPU 58 has an image processing section 581, an optical output control section 582, and a calculation section 583, as shown in FIG. This CPU 58 is part of the light output control unit.

The video processing unit 581 generates video information based on a program stored in the storage unit 57, information input from the input/output I/F 56, information stored in the storage unit 57, and the like. Further, the video processing unit 581 converts the generated video information into three-color video data of red (R), green (G), and blue (B). The converted three-color video data is output to the optical output control section 582 .

The optical output control section 582 controls the optical outputs of the LDs 21a to 21c. For example, the light output control unit 582 takes in image data output from the image processing unit 581 (that is, image information of the image formed on the projection surface 102a) into a memory (not shown) and performs image analysis. That is, the color information, luminance information, and the like of the image formed on the projection surface 102a are analyzed. Further, the light output control section 582 controls the light outputs of the plurality of LDs 21a to 21c based on the analysis results and information on the operating characteristics of the LDs 21a to 21c. The light output control unit 582 generates light control signals for the LDs 21 a to 21 c based on the result of image analysis of the three-color video data, for example, and outputs them to the LD driver 52 . The laser beams emitted from the LDs 21a to 21c based on the light control signals are two-dimensionally scanned by driving the MEMS mirror 31, thereby projecting images (projected images) based on the image information on the windshield 201. Projected to combiner 102 .

The calculator 583 performs various calculations based on the response characteristics of the optical outputs of the LDs 21a to 21c. For example, the calculator 583 calculates rise times TA, TB, and TC of each of the LDs 21a-21c based on the detection results of the PDs 23a-23c. Then, using the rise times TA, TB, and TC, the calculator 583 calculates the times (light emission start times) ta0, tb0, and tc0 at which the driving currents Ia1, Ib1, and Ic1 are applied to the LDs 21a to 21c, and the time differences between them. calculate.

Next, optical output control processing of the LDs 21a to 21c will be described. FIG. 6 is a flowchart for explaining an example of light output control processing of the LDs 21a to 21c according to the first embodiment. The following S101 to S106 are performed during the retrace period, and S107 is performed during the trace period. Note that the optical output control process illustrated in FIG. 6 is also applied to second and third embodiments described later.

First, when the optical axis of the scanning laser light 300 scans the invalid projection area 102c in the retrace period, the light output control section 582 applies predetermined driving currents Ia1 to Ic1 to the LDs 21a to 21c for a predetermined time. That is, the light output control unit 582 causes each of the LDs 21a to 21c to output a predetermined amount of light (eg, Pa1, Pb1, Pc1) (S101). The application time of the driving currents Ia1 to Ic1 may be longer than the rise times TA, TB, TC of the LDs 21a to 21c. Then, the PDs 23a-23c detect the optical outputs of the LDs 21a-21c (S102). The calculator 583 calculates rise times TA, TB, and TC of the LDs 21a-21c based on the detection results of the PDs 23a-23c (S103). Then, the calculator 583 calculates the time differences TB1 (=TA-TB) and TC1 (=TA-TC≈TA) between the longest rising time TA and the other rising times TB and TC (S104). Further, the calculator 583 obtains the light emission start times tb0 and tc0 of the LDs 21b and 21c based on the time differences TB1 and TC1 (S105). The light output control unit 582 loads the video data output from the video processing unit 581 into a memory (not shown), and performs image analysis of the video projected onto the projection surface 102a during the trace period based on the video data (S106). ). That is, the color information and luminance information of the image formed during the trace period are analyzed.

Next, in the trace period, the optical output control unit 582 controls the optical outputs of the LDs 21a to 21c based on the result of the image analysis, the calculation result of the calculation unit 583, the information stored in the storage unit 57, and the like ( S106).

In addition, in the optical output control process described above, S104 may be performed after the optical output control unit 582 identifies the LD having the longest rising time. In this case, the time difference between the specified LD and other LDs is obtained. Normally, the rise time TA of the red LD 21a is the longest, but the rise times Tb and TC of the LDs 21a to 21c may change due to the state of the elements (temperature conversion, deterioration, etc.). Therefore, if the light output control unit 582 functions as an element specifying unit that specifies the LD with the longest rise time as described above, even if the rise time TB of the LD 21b or the rise time TC of the LD 21c is the longest, , the optical output controller 582 can perform similar optical output control. That is, light output control can be performed so that the times ta1, tb1, and tc1 at which the LDs 21a to 21c reach the steady light intensities Pa1, Pb1, and Pc1 are the same.

Next, the light output control of the LDs 21a to 21c when white display is performed from a state where the light quantity is 0 (that is, a state where the light output is 0) will be described in detail with reference to a comparative example and an example.

<Comparative example>
First, a comparative example will be explained. As described above, the rise times TA, TB, and TC at the start of light emission differ among the LDs 21a-21c (see FIGS. 4A-4C). Therefore, when the LDs 21a to 21c simultaneously output light, clear color unevenness occurs in a predetermined period from the light emission start time tS. FIG. 7 is a schematic diagram showing the light output of the scanning laser light 300 when all the LDs 21a to 21c output light simultaneously. In FIG. 7, positions LS, Lb, La, and LE indicate the center positions of the light spot 300c of the scanning laser beam 300 in the scanning direction of the scanning laser beam 300. FIG. A position LS is the center position of the light spot 300c at the light emission start time tS of the LDs 21a to 21c. Position Lb is the center position of light spot 300c at time tb1 of LD 21b. A position La is the center position of the light spot 300c at the time ta1 of the LD 21a. A position LE is the center position of the light spot 300c at the light emission stop time tE of the LDs 21a to 21c. It should be noted that these also apply to FIG. 9 described later.

The scanning laser beam 300 projected onto the projection surface 102a has clear color unevenness between the positions LS and La as shown in FIG. The position LS to La corresponds to a period TA from the light emission start time tS of each of the LDs 21a to 21c to the time ta1 after the rise time TA of the red LD 21a. That is, at the position LS at the light emission start time tS, the scanning laser beam 300 has almost only the blue component. From the position LS to the position Lb, the red and green components of the scanning laser beam 300 gradually increase, but the blue component has a steady light amount Pc1. At position Lb, the green component has a constant light amount Pb1 corresponding to the drive current Ib1, but the light amount of the red component of the scanning laser light 300 is still small and less than the constant light amount Pa1. The red component of the scanning laser beam 300 increases from the position Lb to the position La, and at the position La, the red component has a constant light amount Pa1 corresponding to the drive current Ia1.

<Example>
Next, an example will be described. FIG. 8 is a graph showing an example of light output control of the LDs 21a-21c according to the first embodiment. Also, FIG. 9 is a schematic diagram showing an example of the light output of the scanning laser light 300 when performing the light output control according to the first embodiment.

As shown in FIG. 8, in this embodiment, when an image is formed by the light outputs of the LDs 21a to 21c, the LDs 21a to 21c have steady light amounts Pa1, Pb1, and Pc1 corresponding to the drive currents Ia1, Ib1, and Ic1, respectively. Drive currents Ia1, Ib1 and Ic1 are applied to the LDs 21a to 21c so that times ta1, tb1 and tc1 (≈tc0) are the same. That is, the light output control unit 582 starts applying the driving current to the LD21a having the longest rising time TA among the LDs 21a to 21c based on the time difference between the rising times TA, TB, and TC of the LDs 21a to 21c. The time ta0 is made earlier than the time tb0, tc0 at which the application of the drive current to the other LDs 21b, 21c is started. Further, based on the time difference between the rise times TA, TB, and TC, the light output control unit 582 applies the drive current Ia1 to the LD 21a so that the LD 21a outputs light of a constant light intensity Pa1, to the LD 21a from the other LDs 21b and 21c. Driving currents Ib1 and Ic1 for outputting steady light intensities Pb1 and Pc1, respectively, are applied to the LDs 21b and 21c earlier than time points tb0 and tc0, respectively. Then, the optical output control unit 582 sets the time ta1 at which the light intensity of the LD 21a reaches the steady light intensity Pa1 and the time tb1 and tc1 at which the light intensity of the LDs 21b and 21c reach the steady light intensity Pb1 and Pc1, respectively.

In this case, the time ta0 is set as the light output control start time tS. The drive current Ib1 is applied to the green LD 21b at time tb0 after a time difference TB1 (=TA-TB) from the light emission start time ta0 (that is, time tS) of the red LD 21a, and light emission of the green LD 21b is started. Further, the driving current Ic1 is applied to the blue LD 21c at time tc1 (=ta1) after the time difference TC1 (=TA) from the light emission start time tS, and the blue LD 21c starts to emit light.

By doing this, as shown in FIG. 9, the color unevenness that occurs in the scanning laser light 300 at the positions LS to La is greatly reduced compared to the case where the LDs 21a to LD21c simultaneously emit light (see FIG. 7). That is, since the scanning laser beam 300 has only a small red component between the position LS and the position Lb immediately after the light emission start time tS, the color unevenness is inconspicuous. At position Lb, the green LD 21b starts emitting light, but the red and green components of the scanning laser beam 300 are still small. The red and green components of the scanning laser beam 300 increase from the position Lb to the position La. At the position La, the blue LD 21c starts to emit light, and the red, green, and blue components become constant light intensities Pa1, Pb1, and Pc1 corresponding to the driving currents Ia1, Ib1, and Ic1 applied to the LDs 21a to 21c. .

<Second embodiment>
Next, a second embodiment will be described. In the second embodiment, the light output is controlled so that the times ta2, tb2, and tc2 (≈tc0) at which the LDs 21a to 21c are half the steady light amounts of 0.5Pa1, 0.5Pb1, and 0.5Pc1 are the same. A section 582 controls the optical output of the LDs 21a to 21c. Otherwise, it is the same as the first embodiment. Configurations different from the first embodiment will be described below. Also, the same reference numerals are given to the same components as in the first embodiment, and the description thereof will be omitted.

FIG. 10 is a graph showing an example of light output control of the LDs 21a-21c according to the second embodiment. FIG. 10 shows the response characteristics of the optical outputs of the LDs 21a to 21c when the LDs 21a to 21c perform white display from a state where the amount of light is 0, for example. As shown in FIG. 10, the time ta0 at which the driving current Ia1 that causes the LD 21a to output a constant light intensity Pa1 is applied to the LD 21a is half the rise time (TA/2), (TB/2), (TC/2 ), the driving currents Ib1 and Ic1 are applied to the LDs 21b and 21c, respectively, to output light of constant light intensities Pb1 and Pc1 from the other LDs 21b and 21c, respectively.

Further, as shown in FIG. 10, the driving currents Ia1, Ib1 and Ic1 are applied to the LDs 21a to 21c so that the times ta2, tb2 and tc2 are the same. That is, the light output control unit 582 controls the time ta2 when the LD 21a reaches half the constant light intensity of 0.5 Pa1 and the time ta2 when the LD 21b reaches the constant light intensity of Time tb2 at which half 0.5Pb1 is reached is made the same as time tc2 (=tc0). In other words, based on the time difference between the rise times TA and TB of each of the LDs 21a to 21c, the light output control unit 582 controls the time ta2 at which the light intensity of the LD 21a reaches 50% of the steady light intensity Pa1, and the The time point tb2 at which the light intensity reaches 50% of the constant light intensity Pb1 is the same. In addition, since the LD21c has almost no rise time TC, the time tc2 when half the steady light amount of the LD21c reaches 0.5Pc1 (that is, the time when the ratio to the steady light amount Pc1 reaches 50%) is the same as the time tc0. can be regarded as

In this case, first, the light emission start time ta0 of the LD 21a having the longest rise time is set as the light output control start time tS. Then, the driving current Ia1 is applied to the red LD 21a to start emitting light. Driving current Ib1 is applied to green LD 21b at time tb0 after time TB2 (=(TA−TB)/2) from light emission start time ta0 of red LD 21a, and light emission of green LD 21b is started. The blue LD 21c requires almost no rise time TC (that is, TC≈0). Therefore, the driving current Ic1 is applied to the blue LD 21c at time ta2 after time TC2 (=TA/2) from the light emission start time tS, and the blue LD 21c starts to emit light.

In this embodiment, an example in which the times ta2, tb2, and tc2 are the same has been described, but the present invention is not limited to this example. The times tb2 and tc2 may be later than the time ta2 and earlier than the time ta1. That is, based on the time difference between the rise times TA, TB, and TC, when the light amount of the LD 21a reaches a predetermined ratio with respect to the first light amount Pa1, the light amounts of the LDs 21b and 21c are the above-mentioned relative to the first light amounts Pb1 and Pc1, respectively. The point of time when the predetermined ratio is reached may be the same.

Even in this way, the color unevenness that occurs in the scanning laser light 300 during the period TA from the light emission start time ta0 of the LD 21a to the time ta1 is significantly greater than in the case where the LDs 21a to 21c emit light simultaneously (see FIG. 7). can be reduced to

<Third Embodiment>
Next, a third embodiment will be described. In the third embodiment, the driving currents Ib1 and Ic1 applied to the green LD 21b and the blue LD 21c other than the red LD 21a having the longest rising time TA are increased stepwise, thereby reducing color unevenness in the scanning laser light 300. FIG. Otherwise, it is the same as the first embodiment. Configurations different from those of the first and second embodiments will be described below. Also, the same reference numerals are assigned to the same components as in the first and second embodiments, and the description thereof will be omitted.

FIG. 11 is a graph showing an example of light output control of the LDs 21a-21c according to the third embodiment. FIG. 11 shows the response characteristics of the optical outputs of the LDs 21a to 21c when the LDs 21a to 21c perform white display from a state where the light amount is 0, for example. In FIG. 11, the application start times ta0, tb0 and tc0 of the drive currents Ia1, Ib1 and Ic1 are the same time tS. A constant drive current Ia1 is applied to the red LD 21a during the period from time tS to tE. On the other hand, during the same period, a drive current that increases in two stages is applied to the green LD 21b and the blue LD 21c. However, in this case as well, at the time ta0 at which the driving current Ia1 that causes the LD 21a to output light of the constant light intensity Pa1 is applied to the LD 21a, the driving current Ib1 that causes the other LDs 21b and 21c to output light of the constant light intensity Pb1 and Pc1, respectively. , Ic1 to the LDs 21b, 21c, respectively, earlier than the times tb2a, tc2a.

That is, the light output control unit 582 applies a driving current of a current value (for example, 0.5Ib1) corresponding to a light quantity (for example, 0.5Pb1) less than the steady light quantity Pb1 at time tb0 (=tS) to the green LD 21b. do. After that, the light output control unit 582 applies a drive current of a current value Ib1 corresponding to the steady light amount Pb1 to the LD21b at the time tb2a (=ta0+TA/2) when the light amount of the LD21a is half the steady value 0.5 Pa1. do.

Similarly, the light output control unit 582 applies a driving current of a current value (for example, 0.5Ic1) corresponding to a light quantity (for example, 0.5Pc1) less than the steady light quantity Pc1 at time tc0 (=tS) to the LD 21c. do. After that, the light output control unit 582 applies a driving current of a current value Ic1 corresponding to the steady-state light amount Pc1 to the LD21c at time tc2a (=ta0+TA/2) when the light amount of the LD21a is half the steady-state value 0.5 Pa1. do.

When the drive currents Ib1 and Ic1 are increased in two stages, the times tb2a and tc2a at which the current values applied to the LD21b and LD21c are increased are the times when the LD21a reaches half the constant light intensity of 0.5 Pa1, as shown in FIG. It is desirable that the time is the same as ta2 (=tS+TA/2) or before or after that. In this way, the change in the optical output of the LD21b and the LD21c during the rise time TA of the LD21a (that is, the period from time ta0 to time ta1) can be made close to the change in the optical output of the LD21a.

<Modified example of the third embodiment>
FIG. 12 is a graph showing an example of light output control of the LDs 21a to 21c according to the modified example of the third embodiment. FIG. 12 shows the response characteristics of the light outputs of the LDs 21a to 21c when the LDs 21a to 21c perform white display from a state where the amount of light is 0, for example. As shown in FIG. 12, the drive current applied to the green LD 21b may be increased in three or more steps up to the current value Pb1. Similarly, the drive current applied to the blue LD 21c may also be increased in three or more steps up to the current value Pc1. However, in this case as well, at the time ta0 at which the driving current Ia1 that causes the LD 21a to output light of the constant light intensity Pa1 is applied to the LD 21a, the driving current Ib1 that causes the other LDs 21b and 21c to output light of the constant light intensity Pb1 and Pc1, respectively. , Ic1 to the LDs 21b, 21c, respectively, earlier than the times tb1, tc1.

Furthermore, when the current values applied to the LD 21b and LD 21c are increased in a plurality of stages as shown in FIGS. good too. Also, the intervals between the increasing timings may be constant or different. It is preferable to set the amount of increase and the timing of increase by approximating the change in the optical output of the LD 21a (that is, the increasing tendency of the amount of light) during the rise time TA. In this way, changes in the optical output of the LD21b and the LD21c during the rise time TA of the LD21a can be approximated more closely to the changes in the optical output of the LD21a. Therefore, it is possible to greatly suppress or prevent the occurrence of color unevenness (for example, loss of white balance) in the scanning laser light 300 during the period from when the LDs 21a to 21c start emitting light to when all the LDs 21a to 21c have a steady light amount.

<Summary of the first to third embodiments>
According to the first to third embodiments described above, the projector unit 1 includes a plurality of LDs 21a-21c and a light output control unit. The optical output control unit includes an optical output control section 582 that controls the optical outputs of the plurality of LDs 21a-21c. When the plurality of LDs 21a to 21c perform white display from a state where the light intensity is 0, the light output control unit 582 has the longest rise time TA required to output the light intensity Pa1 for white display among the plurality of LDs 21a to 21c. The driving currents Ib1 and Ic1 for outputting light of white display light amounts Pb1 and Pc1 from the other LDs 21b and 21c are applied to the LD 21a at time ta0 at which the drive current Ia1 that causes the LD 21a to output light of white display light amount Pa1 is applied to the LD 21b. , 21c (for example, tb0, tc0 in FIGS. 8 and 10, tb2a, tc2a in FIG. 11, tb1, tc1 in FIG. 12). (Eleventh configuration)

According to the eleventh configuration, of the LDs 21a to 21c, the LD 21a having the longest rising time TA required to output the light amount Pa1 for white display outputs the driving current Ia1 for outputting the light amount Pa1 for white display. is applied to the LDs 21b and 21c (for example, tb0 and tc0 in FIGS. 8 and 10). , tb2a, tc2a in FIG. 11, and tb1, tc1 in FIG. 12). Therefore, the time ta1 at which the LD 21a outputs the light of the light intensity Pa1 for white display can be brought closer to the time tb1, tc1 at which the LDs 21b, 21c output the light of the light intensity Pb1, Pc1 for the white display. Therefore, when a plurality of LDs 21a to 21c perform white display, it is possible to improve color unevenness caused by differences in light emission delay between the LDs 21a to 21c.

Further, since the color unevenness of the light 300 in the rising time TA of the plurality of LDs 21a to 21c having different emission colors can be improved, deterioration of the color balance (for example, white balance) of the light 300 can be suppressed.

Further, in the light output control unit of the projector unit 1 having the eleventh configuration, the light output control section 582 controls the light output based on the time difference between the rise times TA, TB, and TC of each of the LDs 21a to 21c. The time ta1 at which the light quantity of LD 21b and 21c reaches the white display light quantity Pa1 may be the same as the time tb1 and tc1 at which the light quantity of the other LDs 21b and 21c reaches the white display light quantity Pb1 and Pc1. (Twelfth configuration)

According to the twelfth configuration, the time ta1 at which the LD 21a outputs the light with the light quantity Pa1 for white display and the time tb1, tc1 at which the LDs 21b and 21c output the light with the light quantity Pb1 and Pc1 for white display are the same. The light output is controlled as follows. Therefore, it is possible to further improve color unevenness in the rising time TA of the light 300 output from the LDs 21a to 21c.

Alternatively, in the light output control unit of the projector unit 1 having the eleventh configuration, the light output control section 582 adjusts the light amount of the LD 21a based on the time difference between the rise times TA, TB, and TC of each of the plurality of LDs 21a to 21c. reaches a predetermined ratio with respect to the light quantity Pa1 for white display and the time at which the light quantities of the LDs 21b and 21c reach the above-mentioned predetermined ratios with respect to the light quantity Pb1 and Pc1 for white display may be the same. (13th configuration)

Furthermore, in the thirteenth configuration, the predetermined percentage may be 50%. (14th configuration)

According to the thirteenth and fourteenth configurations, it is possible to improve time-average color unevenness in the rise time TA of the LD 21a. Therefore, deterioration of the color tone balance (for example, white balance) of the light 300 output from the plurality of LDs 21a to 21c can also be suppressed.

Further, in the light output control unit of the projector unit 1 having any one of the eleventh to fourteenth configurations, the light output control section 582 controls the light amount less than the white display light amount Pb1, Pc1 (for example, 0.5Pb1, 0.5Pb1, 0.5Pb1, 0.5Pb1, 0.5Pb1, 0.5Pb1, 0.5Pb1, 0.5Pb1, 0.5Pb1, 0.5Pb1, 0.5Pb1, 0.5Pb1, 0.5Pb1). 5Pc1) is applied to the LDs 21b and 21c with a first current value (e.g. 0.5Ib1, 0.5Ic1) for driving the light outputs of the LDs 21b and 21c, and then the light outputs of the light intensities Pb1 and Pc1 for white display are applied to the LDs 21b and 21c. 21c may be applied to the LDs 21b and 21c. (15th configuration)

According to the fifteenth configuration, the LDs 21b and 21c output light with a light intensity (for example, 0.5Pb1 and 0.5Pc1) lower than the light intensity Pb1 and Pc1 for white display, and then output the light intensity Pb1 and Pc1 for white display. light output. Therefore, the light amount changes of the LDs 21b and 21c during the periods TB and TC from the start of light emission to the light output of the light amounts Pb1 and Pc1 for white display can be made close to the light amount changes of the LD 21a during the rise time TA. Therefore, it is possible to further reduce unevenness in color and deterioration in color tone balance of the light 300 output from the plurality of LDs 21a to 21c.

In the light output control unit of the projector unit 1 having any one of the eleventh to fifteenth configurations, the light output control unit 582 controls the drive current of the LD21b, 21c to the light amount Pb1 for white display, the light of Pc1 to the LD21b, The current values Ib1 and Ic1 output from 21c may be increased in a plurality of steps (see FIGS. 11 and 12). (Sixteenth configuration)

According to the sixteenth configuration, the change in the light amount of the LDs 21b and 21c during the periods TB and TC from the start of light emission until the light output of the light amounts Pb1 and Pc1 for white display is brought closer to the change in the light amount of the LD 21a during the rise time TA. be able to. Therefore, it is possible to further reduce unevenness in color and deterioration in color tone balance of the light 300 output from the plurality of LDs 21a to 21c.

Further, the light output control unit of the projector unit 1 having any one of the eleventh to sixteenth configurations is configured to detect the light amount of each of the plurality of LDs 21a to 21c based on the detection results of the PDs 23a to 23c. 21c may further include a calculator 583 that calculates the rise times TA, TB, and TC of each. (Seventeenth configuration)

According to the seventeenth configuration, the light intensity of each of the plurality of LDs 21a to 21c can be appropriately detected, and the light output control section 582 uses the rising times TA, TB, and TC based on the detection results to Light output can be controlled. Therefore, even if the rising times TA, TB, and TC of each of the LDs 21a to 21c change due to, for example, changes in element temperature or deterioration of the elements, the optical output control section 582 can perform optical output control according to the changes. can.

Further, in the light output control unit of the projector unit 1 having the seventeenth configuration, the light output control section 582 outputs the scanning laser light 300 that is projected onto the projection surface 102a and scanned to form an image on the projection surface 102a. When the scanning laser light 300 is caused to output from the plurality of LDs 21a to 21c and scans the invalid projection region 102c on the projection surface 102a on which no image is formed, the light output control unit 582 causes the plurality of LDs 21a to 21c to emit light, and the calculation unit 583 Alternatively, the rising times TA, TB, and TC may be calculated based on the detection results of the PDs 23a to 23c when the scanning laser beam 300 scans the invalid projection area 102c. (18th configuration)

According to the eighteenth configuration, when the scanning laser beam 300 scans the invalid projection area 102c on the projection surface 102a, the light amount of each of the plurality of LDs 21a to 21c can be appropriately detected, and based on the result, each of the LDs 21a to 21c 21c rise times TA, TB, TC can be calculated. Therefore, by controlling the light output suitable for the actual state of each of the LDs 21a to 21c, the color unevenness of the scanning laser light 300 can be improved, and the quality of the image formed on the projection surface 102a can be improved.

Further, in the light output control unit of the projector unit 1 having any one of the eleventh to eighteenth configurations, a memory (not shown) for storing image information of images formed by the light outputs of the plurality of LDs 21a to 21c is provided. In addition, the optical output control section 582 may be configured to analyze video information and control the optical outputs of the plurality of LDs 21a to 21c based on the analysis results. (Nineteenth configuration)

According to the nineteenth configuration, the light outputs of the LDs 21a to 21c can be controlled based on the analysis result of the image information of the image formed on the projection surface 102a.

<Fourth Embodiment>
Next, a fourth embodiment will be described. In the fourth embodiment, unlike the first embodiment, the portion of the outgoing scanning laser beam 300a in which the amount of light is insufficient due to the rise times TA, TB, and TC of the plurality of LDs 21a to 21c is replaced by the returning scanning laser beam 300b. complement with the amount of light of Configurations different from the first embodiment will be described below. Also, the same reference numerals are assigned to the same components as in the first to third embodiments, and the description thereof is omitted.

FIG. 13 is a schematic diagram locally showing the scanning range of the scanning laser beam 300 continuously reciprocatingly scanned. FIG. 13 shows, for example, a range on projection surface 102a surrounded by solid line A in FIG. As shown in FIG. 13, the scanning pitch (that is, the scanning interval) in the Y direction of each scanning laser beam 300 is larger than the spot diameter 302a of the forward scanning laser beam 300a and the spot diameter 302b of the backward scanning laser beam 300b. small. Therefore, part of the scanning laser beams 300a and 300b continuously reciprocally scanned overlap each other.

13 are a scanning range 301a of the forward scanning laser beam 300a and a scanning range 301b of the backward scanning laser beam 300b, and the two overlap in an overlapping scanning range 301c. Also, hereinafter, the center position in the X direction of the beam spots 302a and 302b of the scanning laser beams 300a and 300b is referred to as a scanning position. The first scanning position H1 is the scanning position at the start of emission of the forward scanning laser light 300a, and the scanning position at the stop of emission of the backward scanning laser light 300b. The second scanning position H2 is the scanning position at the point of time when the outgoing scanning laser light 300a stops emitting light, and the scanning position at the time of starting the emission of the returning scanning laser light 300b.

Here, as described above, each of the plurality of LDs 21a to 21c has rise times TA, TB, and TC at the start of light emission. Therefore, the scanning laser beam 300 has color unevenness from the scanning position at the time of light emission to a predetermined position after the elapse of the rise time. In the present invention, the reduced amount of light in the region where the scanning laser beams 300a and 300b that are continuously reciprocally scanned partially overlap (that is, the overlapping scanning range 301c) is complemented to reduce or eliminate such color unevenness. To prevent. That is, the amount of light of the scanning laser light 300b of the forward path is complemented by the light amount of the scanning laser light 300b of the backward path where the amount of light is insufficient due to the rise times TA, TB, and TC of the plurality of LDs 21a to 21c. Similarly, the light amount of the forward scanning laser light 300a is used to compensate for the insufficient amount of light in the backward scanning laser light 300b due to the rising times TA, TB, and TC of the plurality of LDs 21a to 21c.

In the following, the principle of compensating for the insufficient light quantity of the scanning laser beam 300a by using the averaging of the light quantity will be explained. Control will be mainly described. However, light output control of the other color components of the scanning laser light 300 (that is, the green LD 21b and the blue LD 21c) is similarly performed.

First, the optical outputs of the forward and backward scanning laser beams 300a and 300b are similarly controlled between the first scanning position H1 and the second scanning position H2. FIG. 14 is a graph showing an example of light output control of the red LD 21a in the fourth embodiment. FIG. 14 shows light output control of the red LD 21a from the start of emission of the forward and return scanning laser beams 300a and 300b to the stop of emission thereof.

In FIG. 14, time tS is the time when projection of the red component of scanning laser light 300 (that is, light emission of LD 21a) for forming a projection image based on video information on projection surface 102 is started. Time tS corresponds to the time when the X-direction center position of the beam spot 302a of the forward scanning laser light 300a is at the first scanning position H1, and the X-direction center position of the beam spot 302b of the backward scanning laser light 300b is at the first scanning position H1. It corresponds to the time at the second scanning position H2. Time tE is the time at which the LD 21a stops emitting light. Time tE corresponds to the time when the center position of the forward beam spot 302a in the X direction is at the second scanning position H2, and corresponds to the time when the center position of the backward beam spot 302b in the X direction is at the first scanning position H1. do.

A time ta1 is a time after the rise time TA from the time tS, and is a time when the light output of the LD 21a reaches a constant light amount Pa1 corresponding to the constant drive current Ia1. The time ta3 is a time earlier than the time tE by the same time as the rise time TA. Time ta4 is a time point before time tE for supplementary light time ΔTa, and is a time point at which the LD 21a outputs light of light amount Pa2, which is larger than light amount Pa1 by light amount Pa2. To the LD 21a, a drive current of current value Ia1 is applied between time points tS to ta4, and a drive current of current value Ia2 is applied between time points ta4 to tE. In FIG. 14, the supplementary light time ΔTa is set to 0.5TA, for example, and the corrected light amount ΔPa is set to 0.5Pa1, for example. However, it is not limited to these examples, and the supplementary light time ΔTa may be equal to or less than the rise time TA (0<ΔTa≦TA), and the light amount Pa2 may be equal to or less than twice the light amount Pa1 (that is, ΔPa=Pa2 - 0 < ΔPa ≤ Pa1 at Pa1).

Next, the apparent light amount of the scanning laser light 300 between the first scanning position H1 and the second scanning position H2 perceived by a person viewing the projection surface 102a when the light output control shown in FIG. 14 is performed will be described. Although the apparent light intensity of the red component of the scanning laser beam 300 will be described below in the same manner as in FIG. 14, it goes without saying that the apparent light intensity of the other color components (that is, the green component and the blue component) can also be perceived in the same way. would be

15A to 15C are diagrams for explaining the apparent light amount of the scanning laser light 300 between the first scanning position H1 and the second scanning position H2 in the fourth embodiment. FIG. 15A is a diagram showing changes in optical output of the forward scanning laser beam 300a scanned from the first scanning position H1 to the second scanning position H2 in the fourth embodiment. FIG. 15B is a diagram showing changes in light output of the scanning laser light 300b in the backward pass that scans from the second scanning position H2 to the first scanning position H1 in the fourth embodiment. FIG. 15C is a diagram showing apparent light amount changes of the scanning laser light 300 between the first scanning position H1 and the second scanning position H2 in the fourth embodiment.

It should be noted that in FIGS. 15A to 15C, the horizontal axis of the graph indicates the scanning position of the scanning laser beam 300 unlike in FIG. Therefore, the shape of the graph of the optical output and drive current in FIG. 15A for the forward scanning laser beam 300a and the direction of the horizontal axis are reversed from those in FIG. 15B for the backward scanning laser beam 300b. Also, the graph of FIG. 15C represents the apparent amount of light in the overlapping scanning range 301C (see FIG. 13) between the first scanning position H1 and the second scanning position H2 that humans perceive due to the aforementioned effect of averaging the amount of light. .

A scanning position H3 indicates a scanning position of the forward scanning laser beam 300a after the rising time TA from the start of light emission at the first scanning position H1. A scanning position H6 indicates a scanning position of the forward scanning laser beam 300a before the light emission stop time ΔTa at the second scanning position H2. In the forward scanning laser beam 300a, the scanning positions H1 to H3 correspond to the scanning range HA at the rise time TA (hereinafter referred to as the rising scanning range HA), and the scanning positions H2 to H6 correspond to the compensation before light emission is stopped. It corresponds to the scanning range in the light time ΔTa (hereinafter referred to as supplementary light scanning range ΔHa).

A scanning position H4 indicates a scanning position of the scanning laser beam 300b in the return path after the rising time TA from the start of light emission at the second scanning position H2. Further, a scanning position H5 indicates a scanning position of the scanning laser beam 300b on the backward pass before the light emission stoppage at the first scanning position H1 for the light supplement time ΔTa. In the backward scanning laser beam 300b, the scanning positions H2 to H4 correspond to the rising scanning range HA, and the scanning positions H1 to H5 correspond to the supplementary light scanning range ΔHa.

In the forward and backward scanning laser beams 300a and 300b, the light amount Pa2 in the supplementary light scanning range ΔHa is larger than the light amount Pa1 corresponding to the driving current Ia1 by a supplemental light amount ΔPa. Further, the distance between the scanning positions H1 to H3 for the forward scanning laser beam 300a and the distance between the scanning positions H2 to H4 for the backward scanning laser beam 300b are the same HA. Further, the distance in the X direction between the scanning positions H2 to H6 in the forward scanning laser beam 300a and the distance in the X direction between the scanning positions H1 to H5 in the backward scanning laser beam 300b is the same ΔHa. Since 0<ΔTa≦TA as described above, the distance ΔHa is set to be equal to or smaller than the distance HA (0<ΔHa≦HA).

When the forward and backward scanning laser beams 300a and 300b are scanned, the amount of light between the scanning positions H1 and H2 is perceived by human vision as shown in the graph of FIG. 15C. That is, the insufficient amount of light in the rising scanning range HA (between scanning positions H1 to H3) of the scanning laser beam 300a on the forward pass is corrected by the amount of light supplemented in the supplemental scanning range ΔHa (between scanning positions H1 to H5) of the scanning laser beam 300b on the backward pass. Compensated with ΔPa. In addition, the insufficient amount of light in the rising scanning range HA (between scanning positions H2 to H4) of the scanning laser light 300b on the backward path is corrected by the amount of light supplemented in the scanning range ΔHa (between scanning positions H2 to H6) of the scanning laser light 300a on the forward path. Compensated with ΔPa. Therefore, the amount of light visually sensed by humans between the scanning positions H1 to H3 and between the scanning positions H2 to H4 can be brought closer to the steady amount of light Pa1. Therefore, it is possible to improve the decrease in the amount of light caused by the light emission delay at the start of light emission of the LD 21a.

First, optical output control processing of the LDs 21a to 21c will be described. FIG. 16 is a flowchart for explaining an example of light output control processing of the LDs 21a to 21c according to the fourth embodiment. In the following processing, S201 to S204 are performed during the retrace period, and S205 is performed during the trace period. Note that the optical output control process illustrated in FIG. 16 is also applied to fifth and sixth embodiments described later.

First, in the retrace period, when the optical axis of the scanning laser light 300 scans the invalid projection area 102c, the light output control unit 582 applies the driving currents Ia1 to Ic1 to the LDs 21a to 21c to a predetermined light amount (for example, Pa1, Pb1 , Pc1) (S201). The application time of the driving currents Ia1 to Ic1 may be longer than the rise times TA, TB, TC of the LDs 21a to 21c. The optical outputs of the LDs 21a-21c are respectively detected by the PDs 23a-23c (S202). The calculator 583 calculates rise times TA, TB, and TC of the LDs 21a-21c based on the detection results of the PDs 23a-23c (S203). Further, the light output control unit 582 loads the image data output from the image processing unit 581 into a memory (not shown), and performs image analysis of the projection image projected onto the projection surface 102a during the trace period based on the image data. (S204). That is, it analyzes the color information, luminance information, and the like of the projected image formed during the trace period.

Next, in the trace period, the optical output control unit 582 performs a plurality of light output control of the LDs 21a to 21c (S205). The light output correction information is stored in the storage unit 57, and is data used for compensating for the shortage of the light amount at the rising times TA, TB, and TC of the plurality of LDs 21a to 21c (for example, light supplement time ΔTa described later). and correction light amount ΔPa). Then, the process returns to S201.

In the above, by averaging the optical outputs of the forward and backward scanning laser beams 300a and 300b in the overlapping scanning range 301c (see FIG. 13), an ideal optical output having steady light intensities Pa1, Pb1, and Pc1 can be obtained. I explained what would happen. FIG. 17 is a diagram showing an ideal optical output change of the LD 21a and an actual optical output change of the forward and backward scanning laser beams 300a and 300b in the case of outputting light with a constant light amount Pa1. Note that FIG. 17 shows the change in optical output of the scanning laser beam 300 of the LD 21a. The same applies to the LD21b and LD21c, so the description thereof will be omitted. The upper graph in FIG. 17 shows the change in the amount of light in the ideal light output, and the middle graph shows the actual light output of the forward scanning laser beam 300a that scans from the first scanning position H1 to the second scanning position H2. The lower graph shows the actual change in light output of the scanning laser beam 300b on the return path that scans from the second scanning position H2 to the first scanning position H1.

As shown in the upper graph of FIG. 17, the rises of the ideal light output at the first and second scanning positions H1 and H2 both sharply increase. When such light output is performed, the actual light output at the first and second scanning positions H1 and H2 is sharply increased in the rise at the start of light emission and sharply decreased in the fall at the stop of light emission. There is a need. That is, at the start of light emission, a driving current (see FIG. 24 described later) equal to or higher than the oscillation threshold current Is is supplied to the LD 21a to rapidly increase the scanning laser light 300 to the light amount Pa1. Further, when stopping light emission, the drive current supplied to the LD 21a is decreased from a current value equal to or greater than the oscillation threshold current Is to a current value less than the oscillation threshold current Is, thereby rapidly decreasing the light intensity Pa1 of the scanning laser beam 300. .

However, if the amount of light is rapidly increased at the start of light emission, the amount of light decreases (so-called blunting) due to delay in light emission. Therefore, the light amount of the light output in the rising scanning range HA (between the scanning positions H1 to H3) of the forward scanning laser beam 300a is insufficient and becomes lower than the light amount Pa1 as shown in the middle graph of FIG. Similarly, the light quantity in the rising scanning range HA (between the scanning positions H2 to H4) of the backward scanning laser beam 300b is also insufficient and becomes lower than the light quantity Pa1 as shown in the lower graph of FIG. Therefore, in the supplemental scanning range ΔHa (between scanning positions H2 to H6) of the scanning laser beam 300a on the forward pass, the light output is performed with the light amount Pa2=(Pa1+ΔPa), and the supplemental scanning range ΔHa (scanning position H1 to H5), the light output is performed at the light amount Pa2. By performing such light output, the amount of light that is insufficient in the rising scanning range HA (between the scanning positions H1 to H3) of the scanning laser light 300a on the forward pass is averaged with the corrected light amount ΔPa of the scanning laser light 300b on the backward pass. supplemented by Insufficient light quantity in the rising scanning range HA (between scanning positions H2 to H4) of the backward scanning laser beam 300b is compensated by averaging with the correction light quantity ΔPa of the forward scanning laser beam 300a. Therefore, the ideal light output shown in the upper graph of FIG. 17 is realized by averaging the light output of the forward and backward scanning laser beams 300a and 300b in the overlapping scanning range 301c (see FIG. 13).

It should be noted that unlike the example in FIG. 17, if the rise of the ideal light output at at least one of the first and second scanning positions H1 and H2 is gentle enough to prevent the emission delay from occurring in the actual light output, , no emission delay occurs in the actual scanning laser beam 300 that starts emission at the one scanning position. Therefore, the fall (decrease in the amount of light) at the time of stopping light emission at the one scanning position can also be smoothed to the same degree. These cases are described below.

<Modification of Fourth Embodiment>
First, the case where the rise of the ideal light output on the first scanning position H1 side becomes smooth will be described. FIG. 18 shows the ideal light output change of the LD 21a when the light output gradually rises in the rising scanning range HA1 (between scanning positions H1 to H0a) on the side of the first scanning position H1, and the actual change in the forward and backward passes. is a diagram showing a change in optical output of . It should be noted that FIG. 18 shows the light amount change of the light output of the LD 21a with respect to the scanning position on the projection surface 102 of the scanning laser beam 300 in the scanning direction. The same applies to the LD21b and LD21c, so the description thereof will be omitted. The upper graph in FIG. 18 shows the change in the amount of light in the ideal light output, and the middle graph shows the actual change in the light output of the forward scanning laser beam 300a scanned from the first scanning position to the second scanning position. The lower graph shows the actual change in optical output of the scanning laser beam 300b on the backward pass scanning from the second scanning position to the first scanning position.

As shown in the upper graph of FIG. 18, the ideal rise of the light output on the scanning position H1 side is the rising scanning range HA1 (between the scanning positions H1 and H0a) from 0 until the light quantity reaches the steady light quantity Pa1. ) changes gently. That is, the width (scanning distance) of the rising scanning range HA1 is wider than the width of the rising scanning range HA in the case where the actual scanning laser beam 300 causes emission delay. In other words, on the first scanning position H1 side, the rise of the ideal light output is later than the rise time TA caused by the light emission delay in the actual light output. In such a case, the rise of the forward scanning laser beam 300a (the change in the optical output between the scanning positions H1 to H0a) does not cause an emission delay, and a shortage of the light amount caused by this does not occur. Therefore, the optical output of the forward scanning laser beam 300a at the start of emission changes gently to the same extent as the ideal optical output. In addition, the light output between the scanning positions H1 to H0a before the emission of the backward scanning laser light 300b is stopped also changes gently like the ideal light output.

On the other hand, in FIG. 18, the rise of the ideal light output at the second scanning position H2 sharply increases as in FIG. In such a case, the trailing edge of the forward scanning laser beam 300a is sharply reduced. In addition, the rise of the scanning laser beam 300b on the return path is rapidly increased, but the light amount is decreased (so-called blunted rise) due to the light emission delay. Therefore, the light quantity in the rising scanning range HA (between the scanning positions H2 to H4) of the backward scanning laser beam 300b is insufficient and becomes lower than the light quantity Pa1 as shown in the lower graph of FIG. Therefore, in the supplementary light scanning range ΔHa (between scanning positions H2 to H6) immediately before the emission of the forward scanning laser beam 300a is stopped, the light output is performed at the light amount Pa2=(Pa1+ΔPa), so that the backward scanning laser beam 300b rises. The insufficient amount of light in the scanning range HA (between the scanning positions H2 to H4) is compensated for by the correction light amount ΔPa of the scanning laser light 300a in the forward path. That is, the ideal light output at the second scanning position H2 shown in the upper graph of FIG. and the light output in the scanning range H2 to H4 immediately after the start of emission of the scanning laser light 300b on the return path.

<Another modification of the fourth embodiment>
Next, a description will be given of the case where the rise of the ideal light output on the side of the second scanning position H2 is gentle. FIG. 19 shows the ideal light output change of the LD 21a when the light output gradually rises in the rising scanning range HA2 (between the scanning positions H2 and H0b) on the side of the second scanning position H2, and the actual change in the forward and backward passes. is a diagram showing a change in optical output of . Note that FIG. 19 shows the light amount change of the light output of the LD 21a with respect to the scanning position on the projection surface 102 of the scanning laser light 300 in the scanning direction. The same applies to the LD21b and LD21c, so the description thereof will be omitted. The upper graph in FIG. 19 shows the change in the light amount in the ideal light output, and the middle graph shows the actual light output change in the outward scanning laser beam 300a scanned from the first scanning position to the second scanning position. The lower graph shows the actual change in optical output of the scanning laser beam 300b on the backward pass scanning from the second scanning position to the first scanning position.

As shown in the upper graph of FIG. 19, the rise of the ideal light output at the first scanning position H1 sharply increases as in FIG. In such a case, the rising edge of the scanning laser beam 300a in the forward path is rapidly increased, but the amount of light decreases (so-called blunting) due to the light emission delay. Therefore, the amount of light in the rising scanning range HA (between scanning positions H1 to H3) of the forward scanning laser beam 300a is insufficient and becomes lower than the amount of light Pa1 as shown in the middle graph of FIG. Therefore, in the supplementary light scanning range ΔHa (between scanning positions H1 to H5) immediately before the emission of the backward scanning laser beam 300b is stopped, light output is performed at a light amount Pa2=(Pa1+ΔPa), whereby the forward scanning laser beam 300a rises. The insufficient amount of light in the scanning range HA (between the scanning positions H1 to H3) is compensated for by the corrected light amount ΔPa of the scanning laser beam 300b on the return path. That is, the ideal light output at the first scanning position H1 shown in the upper graph of FIG. and the light output in the scanning range H1 to H3 immediately before the return scanning laser beam 300b stops emitting light.

On the other hand, in FIG. 19, the ideal rise of the light output on the scanning position H2 side is the rising scanning range HA2 (between the scanning positions H2 and H0b) from 0 to the constant light quantity Pa1 in the laser oscillation mode. ) changes gently. That is, the width (scanning distance) of the rising scanning range HA2 is wider than the width of the rising scanning range HA in the case where the actual scanning laser beam 300 causes emission delay. In other words, on the second scanning position H2 side, the rise of the ideal light output is later than the rise time TA caused by the light emission delay in the actual light output. When such light output is performed, no light emission delay occurs at the rising edge of the scanning laser light 300b on the return path (change in light output between scanning positions H2 to H0b), and the resulting lack of light quantity does not occur. Therefore, the optical output of the backward scanning laser beam 300b at the start of emission changes gently to the same extent as the ideal optical output. In addition, the light output between the scanning positions H2 to H0b before the forward scanning laser light 300a stops emitting also changes gently like the ideal light output.

If ideal light output rises smoothly on both the first scanning position H1 side and the second scanning position H2 side, no light emission delay occurs when light emission is started at the actual light output. Therefore, the change in light output of the scanning laser beams 300a and 300b in the forward and backward passes is the same as the ideal change in light output.

<Fifth Embodiment>
Next, a fifth embodiment will be described. In the fifth embodiment, the corrected light amount ΔPa and the light supplement time ΔTa are determined according to the cumulative amount S1 of the insufficient light amount during the rise times TA, TB, and TC of the LDs 21a to 21b. The configuration different from that of the fourth embodiment will be described below. Also, the same reference numerals are assigned to the same components as in the first to fourth embodiments, and the description thereof is omitted.

FIG. 20 is a graph showing an example of light output control of the red LD 21a in the fifth embodiment. Although the optical output control of the LD 21a is described below as an example, the other LDs 21b and 21c can be similarly controlled.

FIG. 20 shows light output control of the red LD 21a from the start to the stop of emission of the forward and backward scanning laser beams 300a and 300b. In FIG. 20, the shortage amount S1 is the cumulative amount of the amount of light that is insufficient (decreased) due to the light emission delay during the rise time TA. That is, the shortage amount S1 is the time integral amount of the light amount difference (Pa1-Pa) between the steady light amount Pa1 corresponding to the driving current Ia1 and the actual light amount Pa at the rising time TA. Further, the correction amount S2 is a cumulative light amount obtained by time-integrating the correction light amount ΔPa in the light supplement time ΔTa.

As shown in FIG. 20, the optical output of the LD 21a is controlled so that the correction amount S2 is the same as the shortage amount S1. In other words, the correction light amount ΔPa and the light supplement time ΔTa are set so as to satisfy S1=S2=ΔPa×ΔTa. Note that the setting method is not particularly limited. For example, the correction light amount ΔPa and the supplementary light time ΔTa may be set within a range that satisfies this condition. Alternatively, one of the correction light amount ΔPa and the light supplement time ΔTa may be set to a fixed value, and the other may be appropriately determined based on the above conditions.

Next, the apparent amount of light of the scanning laser beam 300 between the first scanning position H1 and the second scanning position H2 perceived by a person looking at the projection surface 102a when the light output control shown in FIG. 20 is performed will be described. Although the apparent light amount of the red component of the scanning laser beam 300 will be described below in the same manner as in FIG. 20, it goes without saying that the apparent light amount of the other color components (that is, the green component and the blue component) can also be perceived in the same way. would be

21A to 21C are diagrams for explaining the apparent light amount of the scanning laser light 300 between the first scanning position H1 and the second scanning position H2 in the fifth embodiment. FIG. 21A is a diagram showing changes in optical output of the forward scanning laser beam 300a scanned from the first scanning position H1 to the second scanning position H2 in the fifth embodiment. FIG. 21B is a diagram showing changes in light output of the scanning laser light 300b in the backward pass that scans from the second scanning position H2 to the first scanning position H1 in the fifth embodiment. FIG. 21C is a diagram showing apparent light amount changes of the scanning laser light 300 between the first scanning position H1 and the second scanning position H2 in the fifth embodiment.

It should be noted that in FIGS. 21A to 21C, the horizontal axis of the graph indicates the position of the scanning laser beam 300 in the X direction, unlike in FIG. Therefore, the shape of the graph of the optical output and drive current in FIG. 21A relating to the forward scanning laser beam 300a and the direction of the horizontal axis are reversed from those in FIG. 21B relating to the backward scanning laser beam 300b. Also, the graph of FIG. 21C represents the apparent amount of light in the overlapping scanning range 301C (see FIG. 13) between the first scanning position H1 and the second scanning position H2 that humans perceive due to the aforementioned effect of averaging the amount of light. .

In FIGS. 21A and 21B, the shortage amount s1 is the integrated amount of the insufficient light amount due to the light emission delay in the rise time TA with respect to the scanning distance HA, and corresponds to the shortage amount S1 in FIG. Further, the correction amount s2 is an integral amount of the correction light amount ΔPa with respect to the scanning distance ΔHa in the supplementary light time ΔTa, and corresponds to the correction amount S2 in FIG.

When the forward and backward scanning laser beams 300a and 300b are scanned, the amount of light between the scanning positions H1 and H2 is perceived by human vision as shown in the graph of FIG. 21C. That is, the shortage amount s1 in the rising scanning range HA (that is, between scanning positions H1 to H3) of the scanning laser light 300a on the forward pass is the supplemental light scanning range ΔHa of the scanning laser light 300b on the backward pass (that is, between scanning positions H1 to H5). is supplemented with the correction amount s2 at . Insufficient amount s1 in the rising scanning range HA (that is, between scanning positions H2 to H4) of the scanning laser light 300b on the backward path is the supplemental scanning range ΔHa of the scanning laser light 300a on the forward path (that is, between scanning positions H2 to H6). is supplemented with the correction amount s2 at . Therefore, the amount of light visually sensed by humans between the scanning positions H1 to H3 and between the scanning positions H2 to H4 can be brought closer to the steady amount of light Pa1. Therefore, it is possible to improve the decrease in the amount of light caused by the light emission delay at the start of light emission of the LD 21a.

In the above example, the LD 21a is controlled so that the shortage amount S1 in FIG. 20 becomes the same as the correction amount S2, but the present invention is not limited to this example. The LD 21a may be controlled so that the shortage amount s1 in FIGS. 21A to 21C becomes the same as the correction amount s2. Further, as described above, the green LD 21b and the blue LD 21c are similarly controlled in optical output. Therefore, the edge portion in the X direction of the overlapping scanning range 301c where the forward and backward scanning laser beams 300a and 300b overlap, that is, the scanning range between the scanning positions H1 to H3 and the scanning positions H2 to H5 is controlled by the above-described light output control. It is possible to reduce or prevent color unevenness due to the light emission delay of each of the LDs 21a to 21c in the scanning range between them.

<Sixth Embodiment>
Next, a sixth embodiment will be described. Although the sixth embodiment will be described by exemplifying the green LD 21b, the same applies to the other LDs 21a and 21c. FIG. 22 is a graph showing an example of light output control of the green LD 21b in the sixth embodiment. As shown in FIG. 22, in the sixth embodiment, the rise time TB of the green LD 21b is equally divided into three divided times ΔTb, and the insufficient light quantity in each divided time ΔTb is divided into three stages of corrected light quantities ΔPb1 to ΔPb3. Compensate. Configurations different from those of the fourth and fifth embodiments will be described below. Also, the same reference numerals are given to the same components as in the first to fifth embodiments, and the description thereof will be omitted.

In FIG. 22, the time length of each division time ΔTb is the same. A time point tb5 is a time point ΔTb after the time point tS, and light having a light amount Pb3 is output from the LD 21b. A time point tb6 is a time point 2ΔTb after the time point tS, and light having a light amount Pb2 is output from the LD 21b. A time point tb1 is a time point after the rise time TB (=3ΔTb) from the time point tS. In addition, each light quantity is 0<Pb3<Pb2<Pb1.

Time tb3 is 3ΔTb before time tE, time tb7 is 2ΔTb before time tE, and time tb8 is ΔTb before time tE. From time tb3 to time tb7, the light output control unit 582 applies the drive current Ib2 to the LD 21b, and causes the LD 21b to output light of light intensity Pb4 (=Pb1+ΔPb1). Further, from time tb7 to time tb8, the light output control unit 582 applies the drive current Ib3 to the LD 21b, and causes the LD 21b to output light of light intensity Pb5 (=Pb4+ΔPb2). Further, from the time tb8 to the time tE, the drive current Ib4 is applied to the LD 21b to cause the LD 21b to output the light of the light amount Pb6 (=Pb5+ΔPb3). In addition, each light quantity is Pb1<Pb4<Pb5<Pb6.

Further, each correction light quantity ΔPb1 to ΔPb3 is determined according to the change in light output during the rising time TB of the LD 21b. In particular, it is preferable that the step-like changes in the correction light amounts ΔPb1 to ΔPb3 are brought closer to the light output changes in the rise time TB. For example, the corrected light amount ΔPb1 between time points tb3 and tb7 is set to a numerical value within the range of 0<ΔPb1≦|Pb1−Pb2| according to the change in light output between time points tb6 and tb1. -Pb2|/2. Further, the corrected light amount ΔPb2 between time points tb7 and tb8 is set to a numerical value within the range of 0<ΔPb2≦|Pb2−Pb3| in accordance with the change in light output between time points tb5 and tb6. -Pb3|/2. Further, the corrected light amount ΔPb3 between time tb8 and time tE is set to a numerical value within the range of 0<ΔPb3≦Pb3 according to the change in light output between time tS and time tb5, and is set to (Pb3)/2 in FIG. is set.

Next, the apparent amount of light of the scanning laser beam 300 between the first scanning position H1 and the second scanning position H2 perceived by a human looking at the projection surface 102a when the light output control shown in FIG. 22 is performed will be described. Although the apparent light amount of the green component of the scanning laser beam 300 will be described below in the same manner as in FIG. 22, it goes without saying that the apparent light amount of the other color components (that is, the red component and the blue component) can also be perceived in the same way. would be

23A to 23C are diagrams for explaining the apparent light amount of the scanning laser light 300 between the first scanning position H1 and the second scanning position H2 in the sixth embodiment. FIG. 23A is a diagram showing changes in light output of the forward scanning laser beam 300a scanned from the first scanning position H1 to the second scanning position H2 in the sixth embodiment. FIG. 23B is a diagram showing changes in light output of the scanning laser light 300b in the backward pass that scans from the second scanning position H2 to the first scanning position H1 in the sixth embodiment. FIG. 23C is a diagram showing apparent light amount changes of the scanning laser light 300 between the first scanning position H1 and the second scanning position H2 in the sixth embodiment.

It should be noted that in FIGS. 23A to 23C, the horizontal axis of the graph indicates the X-direction position of the scanning laser beam 300, unlike in FIG. Therefore, the shape of the graph of the optical output and drive current in FIG. 23A relating to the forward scanning laser beam 300a and the direction of the horizontal axis are reversed from those in FIG. 23B relating to the backward scanning laser beam 300b. In addition, FIG. 23C shows the apparent amount of light in the overlapping scanning range 301C (see FIG. 13) between the first scanning position H1 and the second scanning position H2 that humans perceive due to the aforementioned effect of averaging the amount of light.

The first scanning position H1 is the scanning position at the start of emission of the forward scanning laser beam 300a of the LD 21b, and is also the scanning position at the stop of emission of the backward scanning laser beam 300b of the LD 21b. The second scanning position H2 is the scanning position at which the forward scanning laser beam 300a of the LD 21b stops emitting, and also the scanning position at which the LD 21b starts emitting the backward scanning laser beam 300b. The scanning position H3 is the scanning position after the rising time TB from the start of light emission at the first scanning position H1 in the forward scanning laser beam 300a, and the scanning laser light 300b in the backward path after the light emission stop at the first scanning position H1. is also the scanning position 3ΔTb (=TB) before. Further, the scanning position H4 is a scanning position 3ΔTb (=TB) before the emission stop at the second scanning position H2 in the scanning laser beam 300a of the forward pass, and the first scanning position H1 in the scanning laser beam 300b of the backward pass. It is also the scanning position after the rise time TB from the start of light emission at .

In the forward scanning laser beam 300a of the LD 21b, the scanning position H8 indicates a scanning position 2ΔTb before the emission stop at the second scanning position H2. A scanning position H10 indicates a scanning position before the division time ΔTb before light emission is stopped at the second scanning position H2. In the forward scanning laser beam 300a, the scanning positions H1 to H3 correspond to the rising scanning range HB, and the scanning positions H2 to H4 correspond to the supplementary light scanning range ΔHb.

Further, in the scanning laser beam 300b on the return path of the LD 21b, the scanning position H7 indicates a scanning position 2ΔTb before the stop of light emission at the first scanning position H1. A scanning position H10 indicates a scanning position before the division time ΔTb before light emission is stopped at the second scanning position H2. In the backward scanning laser beam 300b, the scanning positions H2 to H4 correspond to the rising scanning range HB, and the scanning positions H1 to H3 correspond to the supplementary light scanning range ΔHb.

The distance between the scanning positions H1 to H3 in the forward scanning laser beam 300a and the distance between the scanning positions H2 to H4 in the backward scanning laser beam 300b are the same HB. Further, scanning positions H2 to H10, scanning positions H8 to H10, and scanning positions H4 to H8 in the forward scanning laser beam 300a, and scanning positions H3 to H7 in the backward scanning laser beam 300b, scanning positions The distance in the X direction between H7 and H9 and between the scanning positions H1 and H9 is the same ΔHb.

When the forward and backward scanning laser beams 300a and 300b are scanned, the amount of light between the scanning positions H1 and H2 is perceived by human vision as shown in the graph of FIG. 23C. That is, between the scanning positions H1 to H3, the insufficient amount of light in the rising scanning range HB of the forward scanning laser beam 300a is uniformly compensated by the corrected light amounts ΔPb1 to ΔPb3 in the supplemental scanning range ΔHb of the backward scanning laser beam 300b. will be Between the scanning positions H2 to H4, the insufficient amount of light in the rising scanning range HB of the scanning laser light 300b of the backward path is uniformly compensated by the correction light amounts ΔPb1 to ΔPb3 of the supplemental scanning range ΔHb of the scanning laser light 300a of the forward path. will be Therefore, the amount of light visually sensed by humans between the scanning positions H1 to H3 and between the scanning positions H2 to H4 can be brought closer to the constant light amount Pb1 corresponding to the constant driving current Ib1. Therefore, it is possible to improve the decrease in the amount of light caused by the light emission delay at the start of light emission of the LD 21b.

Further, as described above, the red LD 21a and the blue LD 21c are similarly controlled in optical output. Therefore, the edge portion in the X direction of the overlapping scanning range 301c where the forward and backward scanning laser beams 300a and 300b overlap, that is, the scanning range between the scanning positions H1 to H3 and the scanning positions H2 to H4 is controlled by the above-described light output control. It is possible to reduce or prevent color unevenness due to the light emission delay of each of the LDs 21a to 21c in the scanning range between them.

Although the correction light amounts ΔPb1 to ΔPb3 are divided into three stages in FIGS. 22 and 23A to 23C, they are not limited to this illustration, and may be divided into a plurality of stages of 2 or 4 or more. As the number of divisions increases, the number of processes increases, but color unevenness can be improved more uniformly and accurately.

<Seventh Embodiment>
Next, a seventh embodiment will be described. In the seventh embodiment, before driving currents of current values Ia1, Ib1, and Ic1 corresponding to steady light amounts Pa1 to Pc1 are applied to each of the LDs 21a to 21c, a minute current value less than the oscillation threshold current Is of each of the LDs 21a to 21c Apply a precurrent of Ip. Configurations different from those of the fourth to sixth embodiments will be described below. Also, the same reference numerals are given to the same components as in the first to sixth embodiments, and the description thereof will be omitted. Further, although the seventh embodiment will be described below by taking the optical output control of the red LD 21a as an example, the optical output control of the other LDs 21b and 21c can be similarly performed.

First, the current-optical output characteristics of the red semiconductor laser element 21a will be described. FIG. 24 is a graph showing optical output characteristics with respect to the driving current of the red LD 21a. As shown in FIG. 24, when the element temperature is 25 degrees, the red LD 21a exhibits the current-optical output characteristics drawn by the solid line graph. The current value Is corresponding to the inflection point of the solid line graph indicates the oscillation threshold current Is of the red LD 21a. The oscillation threshold current Is is a current value indicating the lower limit of the current value at which the red LD 21a emits light only in the laser oscillation mode, and corresponds to the current value IB in FIG. That is, when a current value equal to or higher than the oscillation threshold current Is is applied, the red LD 21a outputs coherent light with a relatively uniform wavelength and phase by stable laser oscillation. On the other hand, when a current value less than the oscillation threshold current Is is applied to the red LD 21a, the emission mode changes and the wavelength and phase of the emitted light become irregular. However, if a current value Ip less than the oscillation threshold current Is is applied to the LD 21a before a drive current equal to or higher than the oscillation threshold current Is is applied to the LD 21a, the light emission delay is suppressed and the rise time TA is remarkably shortened. . In the present embodiment, this phenomenon is used to improve the decrease in the amount of light caused by the light emission delay at the start of light emission of the LD21a to LD21c. That is, during a predetermined period (application time Tp described later) immediately after the scanning laser beams 300a and 300b start emitting light in the scanning range as shown in FIG. apply.

It should be noted that the current value Ip does not need to be far from the oscillation threshold current Is, and may be a slightly smaller current value. Further, as shown in FIG. 24, the current-optical output characteristics of the LD 21a change due to the element temperature and deterioration of the element. Therefore, the current value Ip of the preliminary current is determined according to the current-optical output characteristics (especially the oscillation threshold current Is) corresponding to these conditions.

FIG. 25 is a graph showing an example of light output control of the red LD 21a in the seventh embodiment. FIG. 25 shows light output control of the red LD 21a from the start to the stop of emission of the forward and return scanning laser beams 300a and 300b. In FIG. 25, the time ta9 is the time after the application time Tp from the time tS, and is the time when the LD 21a outputs the light of the light amount Pa1. Further, time ta10 is a time before time tE for supplementary light time ΔTa (=Tp), and is a time point at which the LD 21a outputs light of light amount Pa2, which is larger than light amount Pa1 by light amount Pa2.

A preliminary current of current value Ip is applied to the LD 21a for a predetermined period Tp from time tS to ta9 immediately after the start of light emission. Further, a drive current of current value Ia1 is applied between times ta9 and ta10, and a drive current of current value Ia2 is applied between times ta3 and tE. The application time Tp for applying the preliminary current of the current value Ip to the LD 21a should be longer than the rise time TA of the LD 21a. If Tp≧TA, even if a drive current with a current value Ia1 (>>Ip) is applied to the LD 21a at time ta2, the light emission delay can be greatly suppressed or prevented. On the other hand, if Tp<TA, light emission delay occurs at time ta2.

Next, the apparent amount of light of the scanning laser beam 300 between the first scanning position H1 and the second scanning position H2 perceived by a person looking at the projection surface 102a when the light output control as shown in FIG. 25 is performed will be described. Although the apparent light intensity of the red component of the scanning laser beam 300 will be described below in the same manner as in FIG. 25, it goes without saying that the apparent light intensity of the other color components (that is, the green component and the blue component) can also be perceived in the same way. would be

26A to 26C are diagrams for explaining the apparent light amount of the scanning laser light 300 between the first scanning position H1 and the second scanning position H2 in the seventh embodiment. FIG. 26A is a diagram showing changes in light output of the forward scanning laser beam 300a scanned from the first scanning position H1 to the second scanning position H2 in the seventh embodiment. FIG. 26B is a diagram showing changes in light output of the scanning laser light 300b in the backward pass scanning from the second scanning position H2 to the first scanning position H1 in the seventh embodiment. FIG. 26C is a diagram showing apparent light amount changes of the scanning laser light 300 between the first scanning position H1 and the second scanning position H2 in the seventh embodiment.

It should be noted that in FIGS. 26A to 26C, the horizontal axis of the graph indicates the X-direction position of the scanning laser beam 300, unlike in FIG. Therefore, the shape of the graph of the optical output and drive current in FIG. 26A relating to the forward scanning laser beam 300a and the direction of the horizontal axis are reversed from those in FIG. 26B relating to the backward scanning laser beam 300b. Also, FIG. 26C shows the apparent amount of light in the overlapping scanning range 301C (see FIG. 13) between the first scanning position H1 and the second scanning position H2 that humans perceive due to the above-described effect of averaging the amount of light.

The scanning position H11 is the scanning position after the application time Tp from the start of light emission at the first scanning position H1 in the scanning laser light 300a of the forward pass, and the scanning position H11 is the scanning position after the light emission stop at the first scanning position H1 in the scanning laser light 300b of the backward pass. is also the scanning position before the supplementary light time ΔTa (=Tp). Further, the scanning position H12 is a scanning position in the forward scanning laser beam 300a at the light supplement time ΔTa before the emission stop at the second scanning position H2. It is also the scanning position after the application time Tp from the start of light emission. In the forward scanning laser beam 300a, the scanning positions H1 to H11 correspond to the scanning range at the application time Tp (hereinafter referred to as the application scanning range), and the scanning positions H2 to H12 correspond to the light supplement time ΔTa before the light emission is stopped. It corresponds to the scanning range (that is, the supplementary light scanning range ΔHp). In addition, in the scanning laser beam 300b of the return path, the scanning positions H2 to H12 correspond to the application scanning range at the application time Tp, and the scanning positions H1 to H11 correspond to the supplementary light scanning range ΔHp at the supplementary light time ΔTa before the light emission is stopped. Yes.

In the forward and backward scanning laser beams 300a and 300b, the light amount Pa2 in the supplemental scanning range ΔHp is larger than the light amount Pa1 corresponding to the drive current Ia1 by a supplemental light amount ΔPa. Also, as described above, ΔTa=Tp. Therefore, the distance between the scanning positions H1 to H11 in the forward scanning laser beam 300a and the distance between the scanning positions H2 to H12 in the backward scanning laser beam 300b are the same Hp. Further, the distance in the X direction between the scanning positions H2 to H12 in the forward scanning laser beam 300a and the distance in the X direction between the scanning positions H1 to H11 in the backward scanning laser beam 300b is also Hp.

When the forward and backward scanning laser beams 300a and 300b are scanned, the amount of light between the scanning positions H1 and H2 is perceived by human vision as shown in the graph of FIG. 26C. In other words, the insufficient amount of light in the applied scanning range of the forward scanning laser light 300a is compensated by the correction light amount ΔPa of the supplemental scanning range ΔHp of the backward scanning laser light 300b. Further, the insufficient amount of light in the applied scanning range of the backward scanning laser beam 300b is compensated by the correction light amount ΔPa of the supplemental scanning range ΔHp of the forward scanning laser beam 300a. Therefore, the amount of light visually perceived by humans between the scanning positions H1 to H11 and between the scanning positions H2 to H12 can be brought close to the steady amount of light Pa1 corresponding to the constant driving current Ia1. can be set to Pa1.

In the present embodiment, all the LDs 21a to 21c are configured to apply the preliminary current of the current value Ip for the application time Tp, but the present invention is not limited to this example. This configuration may be applied to at least one of the plurality of LDs 21a to 21c (especially the red LD 21a with the longest rising time).

Next, optical output control processing of the LDs 21a to 21c will be described. FIG. 27 is a flowchart for explaining an example of optical output control processing of the LDs 21a to 21c according to the seventh embodiment. Note that the following S301 to S305 are performed during the retrace period, and S306 is performed during the trace period.

First, in the retrace period, when the optical axis of the scanning laser light 300 scans the invalid projection area 102c, the light output control unit 582 applies predetermined drive currents Ia1 to Ic1 to the LDs 21a to 21c to emit light with a predetermined light intensity (eg Pa1, Pb1, Pc1) (S301). The application time of the driving currents Ia1 to Ic1 may be longer than the rise times TA, TB, TC of the LDs 21a to 21c. The optical outputs of the LDs 21a-21c are respectively detected by the PDs 23a-23c (S302). The calculator 583 calculates rise times TA, TB, and TC of the LDs 21a-21c based on the detection results of the PDs 23a-23c (S303). Further, the calculator 583 sets the application time Tp of the preliminary current of the current value Ip to be applied to each of the LDs 21a to 21c based on the result of S303 (S304). Further, the light output control unit 582 takes in the image data output from the image processing unit 581 into a memory (not shown), and performs image analysis of the projection image projected onto the combiner 102 during the trace period based on the image data. (S305). That is, it analyzes the color information, luminance information, and the like of the projected image formed during the trace period.

Next, in the trace period, the light output control unit 582 controls the light output of the plurality of LDs 21a to 21c based on the image analysis result, the calculation result of the calculation unit 583, the light output correction information read from the storage unit 57, and the like. Output control is performed (S306).

<Summary of fourth to seventh embodiments>
According to the fourth to seventh embodiments described above, the projector unit 101 includes the LDs 21a to LD21c for outputting the scanning laser light 300 with the light intensities Pa1, Pb1, and Pc1 (first light intensities), and on the projection surface 102a. A MEMS engine section 3 for reciprocally scanning the scanning laser light 300 in a predetermined direction (for example, the X direction) having a direction range, and a light output control section 582 for controlling the light output of the LD21a to LD21c, and light output control. If the light amount of the scanning laser beam 300 is to be sharply reduced when the light emission is stopped, the unit 582 determines the light emission stop position in the scanning ranges 301a and 301b scanned by the scanning laser light 300 from the start of light emission to the end of light emission. The second light amount (Pa2, Pb4 to 6, etc.) in the immediately preceding light supplement scanning range ΔHa is made larger than the light amounts Pa1, Pb1, Pc1. (Twentieth configuration)

According to the twentieth configuration, when the scanning laser beam 300 reciprocatingly scans the projection surface 102a and the light amount of the scanning laser beam 300 is sharply reduced at the time of stopping the emission, Light amounts Pa2, Pb4 to 6, etc. (second light amounts) in the scanning areas 301a and 301b scanned by the scanning laser light 300 between the scanning areas 301a and 301b immediately before the emission stop position are light amounts Pa1, Pb1, Pc1 (second light amounts). 1 light amount). Here, since the scanning laser beam 300 is reciprocally scanned, if the light intensity of the scanning laser beam 300 is sharply reduced when the light emission is stopped, the light intensity of the next scanning laser light 300 is normally sharply reduced when the light emission is started. As a result, the amount of light decreases due to the light emission delay (so-called bluntness). On the other hand, according to the above configuration, the light amount that is lower than the light amounts Pa1, Pb1, and Pc1 due to the light emission delay at the start of light emission of the scanning laser light 300a or 300b in one of the forward and backward passes is transferred to the other scanning laser light. It can be supplemented with light amounts Pa2, Pb4 to 6, etc. (second light amounts) in the supplementary light scanning range ΔHa immediately before the emission stop position of the laser beam 300b or 300a. Therefore, it is possible to reduce the decrease in the amount of light of the scanning laser beam 300 visually perceived by humans. Therefore, it is possible to improve the decrease in the amount of light caused by the light emission delay at the start of light emission of the LDs 21a to 21c.

Further, the projector unit 101 having the twentieth configuration further includes a memory (not shown) for storing image information (video data) to be formed on the projection surface 102a, and the light output control section 582 analyzes the image information. Then, the optical output may be controlled based on the result of the analysis. (21st configuration)

According to the twenty-first configuration, the light outputs of the LDs 21a to 21c can be controlled based on the analysis result of the image information formed on the projection surface 102a.

Further, in the projector unit 101 having the above configuration of the twentieth or twenty-first configuration, the light output control section 582 controls the rise time TA from the start of light emission until reaching the light output of the light amounts Pa1, Pb1, Pc1 (first light amount). If the fall time from the start of decrease of the light amount of the scanning laser beam 300 to the stop of light emission is shorter than the above, the light amounts Pa2, Pb4 to 6, etc. (second light amounts) may be made larger than the light amounts Pa1, Pb1, Pc1. . (22nd configuration)

According to the twenty-second configuration, when the fall time at the time of stopping light emission is shorter than the rise time TA at the time of starting light emission, the light amount of the scanning laser light 300a or 300b is rapidly reduced when light emission is stopped. there is Therefore, when the next scanning laser beam 300b or 300a starts to emit light, the amount of light usually decreases due to the delay in light emission. can compensate.

Further, in the projector unit 101 having any one of the 20th to 22nd configurations, the light output control section 582 sets the light emission start position and the light emission stop position of the scanning range 301a with the scanning laser light 300a in the forward pass respectively. It may be configured to correspond to the light emission stop position and the light emission start position of the scanning range 301b of the laser light 300b. (23rd configuration)

According to the twenty-third configuration, when the scanning laser beam 300a or 300b in one of the forward and backward paths starts to emit light, the amount of light becomes lower than the amount of light Pa1, Pb1, and Pc1 (first amount of light) due to the light emission delay. The second light quantity (Pa2, Pb4 to 6, etc.) of the other scanning laser beam 300b or 300a can be more reliably compensated for the light quantity.

Further, in the projector unit 101 having the 23rd configuration, in a predetermined direction (for example, the X direction) having a directional range, the supplementary light scanning range ΔHa with the scanning laser light 300a on the forward pass starts emission in the scanning laser light 300b on the backward pass. It may overlap with the rising scanning ranges HA and HB scanned by the scanning laser beam 300b in the return path until the optical outputs of the light intensities Pa1, Pb1, and Pc1 (first light intensities) are reached. Further, the supplemental scanning range ΔHa of the backward scanning laser beam 300b is defined as the forward scanning laser beam 300a scanning the forward scanning laser beam 300a from the start of light emission to the light output of the light intensities Pa1, Pb1, and Pc1. It may be configured to overlap with the rising scanning ranges HA and HB. (24th configuration)

According to the twenty-fourth configuration, the supplementary light scanning range ΔHa can be overlapped with the rising scanning ranges HA and HB. It should be noted that the light amount of the scanning laser beam 300 is greater than the light amounts Pa1, Pb1, and Pc1 (first light amount) in the supplementary light scanning range ΔHa, and the scanning laser light 300 is larger than the light amount Pa1, Pb1, and Pc1 (first light amount) in the rising scanning ranges HA and HB due to light emission delay. is lower than the light intensities Pa1, Pb1, and Pc1. Therefore, it is possible to reliably project the scanning laser light 300 having a light amount larger than the light amounts Pa1, Pb1, Pc1 onto the rising scanning ranges HA, HB.

Further, in the projector unit 101 having the twenty-third or twenty-fourth configuration, in a predetermined direction (for example, the X direction) having a directional range, the scanning distance in the supplemental scanning range ΔHa of the forward scanning laser beam 300a is A configuration may be adopted in which the scanning distance is equal to or less than the scanning distances in the rising scanning ranges HA and HB of the scanning laser beam 300b. Further, the scanning distance in the light supplement scanning range ΔHa of the backward scanning laser beam 300b may be less than or equal to the scanning distance in the rising scanning ranges HA and HB of the forward scanning laser beam 300a. (25th configuration)

According to the twenty-fifth configuration, light intensities Pa1, Pb1, and Pc1 (first light intensities) are applied to the scanning ranges 301a and 301b other than the rising scanning areas HA and HB where the light intensity decreases due to light emission delay. It is possible to avoid projecting the scanning laser light 300 having a light amount Pa2, Pb4 to Pb6, etc. (second light amount).

Further, in the projector unit 101 having any one of the 23rd to 25th configurations, the light output control section 582 controls the cumulative light amounts S2 and s2 in the scanning laser beams 300a and 300b of the forward and backward passes in the supplementary light scanning range ΔHa. A configuration may be adopted in which the accumulated amounts S1 and s1 of the reduced light amounts due to the light emission delay of the LDs 21a to 21c are the same. (26th configuration)

According to the twenty-sixth configuration, by complementing the cumulative amounts S1 and s1 of the light amounts that have decreased due to the light emission delay with the cumulative light amounts S2 and s2 in the supplementary light scanning range ΔHa, the light emission delay perceived by human vision is It is possible to more effectively improve or eliminate the decrease in the light amount of the scanning laser beams 300a and 300b caused by the above.

Further, the projector unit 101 having any one of the twentieth to twenty-sixth configurations above further includes an LD driver 52 that supplies drive currents to the LDs 21a to 21c. , when the light intensity of the scanning laser beam 300 is sharply reduced when the light emission is stopped, a first current value equal to or higher than the oscillation threshold current Is indicating the lower limit of the current value at which the LDs 21a to 21c emit light only in the laser oscillation mode is adjusted from the oscillation threshold value. A configuration may be employed in which the drive current is reduced to a second current value less than the current Is. (27th configuration)

According to the twenty-seventh configuration, the light amount of the scanning laser light 300 emitted from the LDs 21a to 21c that emit light only in the laser oscillation mode can be rapidly reduced.

Further, in the projector unit 101 having any one of the 20th to 27th configurations, the light output control section 582 divides the light amounts Pb4 to 6 (for example, see FIG. 22) in the supplementary light scanning range ΔHa into a plurality of stages. It is good also as a structure which makes it increase. (28th configuration)

According to the twenty-eighth configuration, the scanning laser beam 300 can be projected according to the distribution of the amount of light that has decreased due to the light emission delay. Therefore, it is possible to more uniformly improve the decrease in the amount of light caused by the light emission delay at the start of light emission of the LDs 21a to 21c.

Further, in the projector unit 101 having any one of the 20th to 28th configurations, the LDs 21a to 21c are semiconductor laser elements, and the scanning laser beams 300a and 300b in the scanning ranges 301a and 301b are emitted for a predetermined period immediately after the start of emission. At Tp, the LDs 21a to 21c may be supplied with a preliminary current having a current value Ip that is less than the oscillation threshold current Is indicating the lower limit of the current value at which the LDs 21a to 21c emit light only in the laser oscillation mode. (29th configuration)

According to the twenty-ninth configuration, it is possible to suppress or prevent the light emission delay of the LDs 21a to 21c by previously applying a preliminary current having a current value Ip less than the oscillation threshold current Is to the LDs 21a to 21c.

Further, in the projector unit 101 having the above configuration of the twenty-ninth configuration, the application time Tp of the preliminary current (current value Ip) is set to the light amounts Pa1, Pb1, Pc1 (first light amounts) after the LDs 21a to 21c start emitting light. A configuration may be adopted in which the rise times TA, TB, and TC required to reach the optical output are longer. (Thirtieth configuration)

According to the thirtieth configuration, the application time Tp of the preliminary current of the current value Ip is set to be equal to or longer than the rise times TA, TB, TC.

Further, according to the fourth to seventh embodiments, the projector unit 101 controls the LDs 21a to 21c that emit the laser light 300, the MEMS engine section 3 that scans the laser light 300, and the light amounts of the LDs 21a to 21c. and a light output control unit 582, the light output control unit 582 starts and stops the light emission of the LDs 21a to 21c in the forward path and the return path. The scanning range until the stop is the rising scanning range HA from the start of the light emission until the light amount becomes the first light amount Pa1, Pb1, Pc1, and the light amount is the first light amount Pa1, Pb1, Pc1. between H3 and H6 on the forward pass, between H4 and H5 on the return pass, and after the light quantity reaches a second light quantity (Pa2, Pb4 to 6, etc.) larger than the first light quantity Pa1, Pb1, Pc1. The length of the supplementary light scanning range ΔHa is equal to or less than the length of the rising scanning range HA. (31st configuration)

Further, the projector unit 101 having the thirty-first configuration further includes a storage section 57 for storing the image information of the projection image, and the light output control section 582 analyzes the image information, and based on the result of the analysis, to control the amount of light. (32nd configuration)

In the projector unit 101 having the 31st or 32nd configuration, the light emission start position and the light emission stop position in the rising scanning range HA of the forward pass are respectively the light emission stop position and the light emission start position in the light supplement scanning range ΔHa of the return pass. It is configured to correspond to the position. (33rd Configuration)

In the projector unit 101 having the thirty-third configuration, the rising scanning range HA of the laser light 300a on the forward path overlaps the supplementary light scanning range ΔHa of the laser light 300b on the backward path. (34th configuration)

Further, in the projector unit 101 having the thirty-third or thirty-fourth configuration, the length of the auxiliary light scanning range ΔHa of the laser light 300a on the forward path is equal to the length of the rising scanning range HA of the laser light 300b on the backward path. The configuration is as follows. (35th configuration)

Further, in the projector unit 101 having the thirty-third to thirty-fifth configurations, the light output control section 582 controls the cumulative light amount in the supplementary light scanning range ΔHa of the at least one laser beam 300 to It is configured to equalize the cumulative amount of the reduced amount of light due to the light emission delay of the light emitting element that outputs the laser light 300 . (36th configuration)

Further, the projector unit 101 having the thirty-sixth configuration further includes an LD driver 52 that supplies a driving current to a light emitting element that outputs the laser beam 300, and the light emitting element is a semiconductor laser element, and the LD driver 52 is from a first current value equal to or higher than the oscillation threshold current Is indicating the lower limit of the current value at which the semiconductor laser element emits light only in the laser oscillation mode in the supplementary light scanning range ΔHa of the at least one laser beam 300. The drive current is reduced to a second current value less than the oscillation threshold current Is. (37th configuration)

Further, in the projector unit 101 having the thirty-sixth or thirty-seventh configuration, the light emitting element is a semiconductor laser element, and the predetermined period Tp after the start of the emission of the laser light 300 in the vertical scanning range HA is 3, a preliminary current having a current value Ip less than the oscillation threshold current Is indicating the lower limit of the current value at which the semiconductor laser device emits light only in the laser oscillation mode is applied to the semiconductor laser device. (38th configuration)

Further, in the projector unit 101 having the thirty-eighth configuration, the application time Tp of the preliminary current (current value Ip) is set from the start of light emission of the semiconductor laser element until the light amount reaches the first light amounts Pa1, Pb1, and Pc1. The time TA, TB, and TC required for the above is longer than or equal to the time TA, TB, and TC. (39th configuration)

Further, in the projector unit 101 having the 31st to 39th configurations, the light output control section 582 divides the second light amount (Pa2, Pb4 to 6, etc.) in the supplementary light scanning range ΔHa into a plurality of stages. It is configured to be increased by (40th configuration)

The embodiments of the present invention have been described above. It should be understood by those skilled in the art that the above-described embodiment is an example, and that various modifications are possible in the combination of each component and each process, and that they are within the scope of the present invention.

For example, in the first to seventh embodiments described above, some or all of the constituent elements 581 to 583 of the CPU 58 may be functional constituent elements, or may be physical components such as electric circuits, devices, and devices. It may be a component. Also, at least some of the components 581 to 583 may be components independent of the CPU 58 .

Further, in the first to seventh embodiments described above, the laser projector 101 of the HUD device 100 has been described, but the scope of application of the present invention is not limited to these examples. INDUSTRIAL APPLICABILITY The present invention can be widely applied to any device that performs light output control of a plurality of light sources with different emission wavelengths.

100 head-up display device (HUD device)
REFERENCE SIGNS LIST 101 projector unit 102 combiner 200 vehicle 201 windshield 300 scanning laser beam 400 user's line of sight 1 housing 1a window 2 optical engine 21a to 21c laser diode (LD)
22 optical system 221a-221c collimator lens 222a-222c beam splitter 223 condenser lens 23a-23c photodetector (PD)
3 MEMS engine unit 31 MEMS mirror 50 main housing 50a light exit port 51 MEMS mirror driver 52 LD driver 53 power source 54 power control unit 55 operation unit 56 input/output I/F
57 storage unit 58 CPU
581 Video processing unit 582 Optical output control unit 583 Calculation unit

Claims (10)

An optical output control unit that controls the optical output of a plurality of light emitting elements with different emission wavelengths,
The plurality of light emitting elements are
a first light emitting element having the longest optical response time;
a second light emitting device having a shorter optical response time than the first light emitting device;
a third light emitting element that immediately emits light with an amount of light corresponding to the current value of the applied drive current;
has
When the plurality of light emitting elements perform display from a state in which the amount of light is 0, the light output control unit applies a second driving current to the second light emitting elements at the time when the first driving current is applied to the first light emitting elements. Earlier than the time of application and the time of applying the third drive current to the third light emitting element ,
The optical response time is required from the time when the drive current for displaying the image is applied to the output of the light amount corresponding to the drive current in the first light emitting element and the second light emitting element . is time,
The first drive current is the drive current for causing the first light emitting element to output the amount of light for the display,
The second drive current is the drive current for causing the second light emitting element to output the amount of light for the display,
The third drive current is the drive current for causing the third light emitting element to output the amount of light for the display,
the amount of light corresponding to the driving current of the first light emitting element and the second light emitting element is respectively larger than the amount of light when the first light emitting element and the second light emitting element start emitting light;
The light output control unit controls the light output based on the time difference between the light response times of the first light emitting element and the second light emitting element so that the light intensity of each of the light emitting elements corresponds to the driving current. A light output control unit that achieves the same amount of light at the same time. An optical output control unit that controls the optical output of a plurality of light emitting elements with different emission wavelengths,
The plurality of light emitting elements are
a first light emitting element having the longest optical response time;
a second light emitting device having a shorter optical response time than the first light emitting device;
a third light emitting element that immediately emits light with an amount of light corresponding to the current value of the applied drive current;
has
When the plurality of light emitting elements perform display from a state in which the amount of light is 0, the light output control unit applies a second driving current to the second light emitting elements at the time when the first driving current is applied to the first light emitting elements. Earlier than the time of application and the time of applying the third drive current to the third light emitting element ,
The optical response time is required from the time when the drive current for displaying the image is applied to the output of the light amount corresponding to the drive current in the first light emitting element and the second light emitting element . is time,
The first drive current is the drive current for causing the first light emitting element to output the amount of light for the display,
The second drive current is the drive current for causing the second light emitting element to output the amount of light for the display,
The third drive current is the drive current for causing the third light emitting element to output the amount of light for the display,
The light output control unit controls the amount of light of the first light emitting element relative to the amount of light corresponding to the first driving current based on the time difference between the light response times of the first light emitting element and the second light emitting element . a time point at which the amount of light from the second light emitting element reaches a predetermined ratio with respect to the light amount corresponding to the second drive current; and a time point at which the third drive current is applied to the third light emitting element. make the time and , the same,
In the first light-emitting element and the second light-emitting element , the light intensity at the time when the light intensity corresponding to the drive current reaches the predetermined ratio is respectively A light output control unit that is greater than the amount of light. 3. A light output control unit according to claim 2, wherein said predetermined percentage is 50%. An optical output control unit that controls the optical output of a plurality of light emitting elements with different emission wavelengths,
The plurality of light emitting elements are
a first light emitting element having the longest optical response time;
a second light emitting device having a shorter optical response time than the first light emitting device;
a third light emitting element that immediately emits light with an amount of light corresponding to the current value of the applied drive current;
has
When the plurality of light emitting elements perform display from a state in which the amount of light is 0, the light output control unit applies a second driving current to the second light emitting elements at the time when the first driving current is applied to the first light emitting elements. Earlier than the time of application and the time of applying the third drive current to the third light emitting element ,
The optical response time is required from the time when the drive current for displaying the image is applied to the output of the light amount corresponding to the drive current in the first light emitting element and the second light emitting element . is time,
The first drive current is the drive current for causing the first light emitting element to output the amount of light for the display,
The second drive current is the drive current for causing the second light emitting element to output the amount of light for the display,
The third drive current is the drive current for causing the third light emitting element to output the amount of light for the display,
the amount of light corresponding to the driving current of the first light emitting element and the second light emitting element is respectively larger than the amount of light when the first light emitting element and the second light emitting element start emitting light;
The optical output control unit is
applying to the second light emitting element the second drive current having a first current value that causes the second light emitting element to output a light amount less than the light amount for displaying, and applying the second driving current to the second light emitting element less than the light amount for displaying. After applying to the third light emitting element the third driving current having a second current value that causes the third light emitting element to output a light amount of
applying to the second light emitting element the second driving current having a third current value for causing the second light emitting element to output the light amount for displaying, and outputting the light amount for displaying the light output; A light output control unit for applying, to the third light emitting element, the third driving current having a fourth current value to drive the third light emitting element . An optical output control unit that controls the optical output of a plurality of light emitting elements with different emission wavelengths,
The plurality of light emitting elements are
a first light emitting element having the longest optical response time;
a second light emitting device having a shorter optical response time than the first light emitting device;
a third light emitting element that immediately emits light with an amount of light corresponding to the current value of the applied drive current;
has
When the plurality of light emitting elements perform display from a state in which the amount of light is 0, the light output control unit applies a second driving current to the second light emitting elements at the time when the first driving current is applied to the first light emitting elements. Earlier than the time of application and the time of applying the third drive current to the third light emitting element ,
The optical response time is required from the time when the drive current for displaying the image is applied to the output of the light amount corresponding to the drive current in the first light emitting element and the second light emitting element . is time,
The first drive current is the drive current for causing the first light emitting element to output the amount of light for the display,
The second drive current is the drive current for causing the second light emitting element to output the amount of light for the display,
The third drive current is the drive current for causing the third light emitting element to output the amount of light for the display,
the amount of light corresponding to the driving current of the first light emitting element and the second light emitting element is respectively larger than the amount of light when the first light emitting element and the second light emitting element start emitting light;
The light output control section controls the second drive current for the second light emitting element and the third drive current for the third light emitting element, respectively , and controls the amount of light for the display to the second light emitting element and the third light emitting element. A light output control unit for increasing the current output from the third light emitting element in a plurality of stages. The optical output control unit is
applying to the second light emitting element the second drive current having a first current value that causes the second light emitting element to output a light amount less than the light amount corresponding to the second drive current; After applying to the third light emitting element the third driving current having a second current value that causes the third light emitting element to output a light amount less than the corresponding light amount ;
applying to the second light emitting element the second driving current having a third current value that causes the second light emitting element to output a light amount corresponding to the driving current, and outputting a light amount corresponding to the driving current; 4. The light output control unit according to any one of claims 1 to 3, wherein the third drive current having a fourth current value for driving the third light emitting element is applied to the third light emitting element . The light output control section controls the second drive current for the second light emitting element and the third drive current for the third light emitting element, respectively , and outputs light of a light amount corresponding to the second drive current to the second light emitting element. 4. The light output control unit according to any one of claims 1 to 3, wherein the current value to be output from the third light emitting element is increased in a plurality of stages. 3. The apparatus further comprises a calculator that calculates the photoresponse time of each of the first light emitting element and the second light emitting element based on a detection result of a light detector that detects the amount of light of each of the plurality of light emitting elements. The optical output control unit according to any one of claims 1 to 7. further comprising a memory for storing image information of an image formed by the light outputs of the plurality of light emitting elements;
9. The light output control unit according to any one of claims 1 to 8, wherein the light output control section analyzes the image information and controls the light outputs of the plurality of light emitting elements based on the analysis result. a light output control unit according to any one of claims 1 to 9;
A light projection device comprising: a plurality of light emitting elements.

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