JP2018200814A - Display unit - Google Patents

Abstract

To provide a display unit that can perform good light control.SOLUTION: A display unit comprises: drive control means that controls to drive light emitting means in a field sequential system to emit light in colors different for each of sub frame periods; light intensity detection means that detects the light intensity of emission light for each of the colors; and integration means that supplies, to the drive control means, sum total information indicating the sum total of the light intensities in a predetermined period longer than the sub frame period. The drive control means calculates the ratio of the colors in the light intensities on the basis of the sum total information in a current predetermined period, controls to drive the light emitting means after the lapse of the current predetermined period such that the calculated ratio matches the ratio of the colors in set target light intensity, and controls to drive the light emitting means also within the current predetermined period such that the ratio of the colors in the light intensities calculated on the basis of the sum total information in a predetermined period before the current one matches the ratio of the colors in the set target light intensity.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a display device, and more particularly to a display device that displays an image in a field sequential manner.

  As a display device that displays an image by a field sequential method, for example, there is one disclosed in Patent Document 1. The display device according to Patent Document 1 generates an image by reflecting light from a plurality of light sources having different emission colors by a DMD (Digital Micro-mirror Device) which is a reflective display element. This display device performs dimming control by feedback control so that the light emission intensity of the light source detected by the light intensity detection unit made of, for example, a photodiode approaches the set target light intensity.

JP 2017-33645 A

  In the display device as described above, for example, when the target light intensity is set to be relatively small in accordance with the darkness of the periphery of the device, the light emission intensity of the light source is controlled to be small in accordance with the target light intensity. In this case, the light emission intensity detected by the light intensity detection unit is too small, and the current light emission intensity cannot be accurately specified, and there is a possibility that accurate light control cannot be realized.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a display device capable of performing good light control.

In order to achieve the above object, a display device according to the present invention includes:
A display device that displays an image in a field sequential manner,
A light emitting means for emitting light of a plurality of colors;
Drive control means for driving and controlling the light emitting means in a field sequential manner so as to emit light of different colors for each subframe period obtained by time-dividing a frame period which is a display period of the image;
A display element that generates light representing the image based on the emitted light emitted by the light emitting means;
A light intensity detecting means for detecting a light intensity for each color of the emitted light;
Integrating means for supplying sum information indicating the sum of the light intensities in a predetermined period longer than the subframe period to the drive control means,
The drive control means includes
The ratio of each color of the light intensity is calculated based on the total information for the predetermined period of time, and the ratio of the color of the target light intensity is set so that the calculated ratio matches the ratio of each color of the set target light intensity. Drive control of the light emitting means after elapse,
The light emitting means also in the predetermined period of this time so that the ratio of each color of the light intensity calculated based on the total information in the predetermined period before this time coincides with the ratio of each color of the target light intensity. Drive control,
It is characterized by that.

  According to the present invention, good dimming control can be performed.

It is a figure for demonstrating the display mode of the display apparatus which concerns on 1st Embodiment of this invention. It is a schematic block diagram of a display apparatus. It is a schematic diagram which shows the structure of the illuminating device with which a display apparatus is provided. It is a block diagram of the light source drive device with which a display apparatus is provided. It is a figure which shows the structural example of the logic circuit with which a light source drive device is provided. (A)-(f) is a timing chart for demonstrating various signals and drive current. It is a schematic circuit diagram of the light intensity integration means with which a light source drive device is provided. It is a timing chart for demonstrating the electrical storage and discharge in a light intensity integration means. It is a flowchart of the light control process which concerns on 1st Embodiment. It is a flowchart of the charge object color selection process which concerns on 1st Embodiment. It is a timing chart for demonstrating the electrical storage and discharge in the light intensity integration means which concerns on a modification. It is a flowchart of the light control process which concerns on 2nd Embodiment of this invention. It is a flowchart of the short-term correction process which concerns on 2nd Embodiment.

  An embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1, the display device 1 according to the first embodiment is configured as a head-up display (HUD) device disposed on the dashboard of the vehicle 2, and is schematically illustrated in FIG. 2. The display light L representing the image M to be shown is emitted toward the windshield 3 (front glass). The display light L reflected by the windshield 3 is visually recognized by the observer 4 (mainly the driver of the vehicle 2) as a virtual image V of the image M in front of the windshield 3. In this way, the display device 1 displays the image M that is visually recognized as the virtual image V, superimposed on the scenery in front of the vehicle 2. The image M is an image for informing vehicle information related to the vehicle 2 such as vehicle speed, engine speed, and navigation information. The vehicle information includes not only information on the vehicle 2 itself but also information outside the vehicle 2.

  As shown in FIG. 2, the display device 1 includes an illumination device 10, an illumination optical system 30, a display element 40, a projection optical system 50, a screen 60, a reflection optical system 70, and a housing 80. Prepare. Further, the display device 1 includes a light source driving device 5 shown in FIG.

  The illumination device 10 emits light RGB (illumination light C), which will be described later, toward the illumination optical system 30, and as shown in FIG. 3, a light source unit 11 (an example of a light emitting unit), a circuit board, and the like. 12, a multiplexing unit 13, a luminance unevenness reducing unit 14, and a transmission film 15.

  The light source unit 11 includes a light source 11r that emits red light R (hereinafter also referred to as a red light source), a light source 11b that emits green light G (hereinafter also referred to as a green light source), and a light source 11b that emits blue light B (hereinafter referred to as blue light source). Also called a light source). Each of the light sources 11r, 11g, and 11b is comprised from the light emitting diode (LED (Light Emitting Diode)), for example. Each of the light sources 11r, 11g, and 11b is driven in a field sequential manner by the light source driving device 5, and emits light at a predetermined light intensity and timing. The circuit board 12 is made of, for example, a printed circuit board, and light sources 11r, 11g, and 11b are mounted thereon.

  The multiplexing means 13 is emitted from the light sources 11r, 11g, and 11b, combines the arrived lights R, G, and B, and emits them as light RGB. Specifically, the multiplexing means 13 includes a reflecting portion 13a made of a reflecting mirror, and combining portions 13b and 13c made of dichroic mirrors that reflect light of a specific wavelength but transmit light of other wavelengths. Have. The reflection part 13a is located on the emission side of the light source 11b. The reflection unit 13a reflects the incident blue light B toward the multiplexing unit 13b. The multiplexing unit 13b is located on the emission side of the light source 11g. The multiplexing unit 13b reflects the incident green light G toward the multiplexing unit 13c and transmits the blue light B from the reflecting unit 13a as it is. Thereby, the light BG obtained by combining the blue light B and the green light G is emitted from the combining unit 13b toward the combining unit 13c. The multiplexing unit 13c is located on the emission side of the light source 11r. The multiplexing unit 13c reflects the incident red light R toward the illumination optical system 30, and transmits the light BG from the multiplexing unit 13b as it is. In this way, the light RGB (hereinafter also referred to as illumination light C) obtained by combining the light BG and the red light R is emitted toward the illumination optical system 30 from the multiplexing unit 13c.

  The luminance unevenness reducing unit 14 includes a mirror box, an array lens, and the like, and reduces unevenness of light by irregularly reflecting, scattering, and refracting the illumination light C from the multiplexing unit 13.

  The transmissive film 15 is made of a transmissive member having a reflectivity of, for example, about 5%, and transmits most of the illumination light C that has arrived through the luminance unevenness reducing unit 14 as it is, but detects a part of the light intensity. Reflected in the direction of the part 500. As shown in FIG. 3, a light intensity detection unit 500 described later is provided at a position where the illumination light C reflected by the transmission film 15 is received. The light intensity detection unit 500 receives the illumination light C and detects the light intensities of the lights R, G, and B in a time division manner. Note that the light intensity detection unit 500 only needs to be able to detect the light intensities of R, G, and B. For example, each of the light R, G, and B before being combined is not the optical path of the illumination light C. It may be provided at a location where the light intensity can be detected.

  The illumination device 10 emits light from the light source unit 11 toward the illumination optical system 30 as light RGB (illumination light C) through the multiplexing unit 13, the luminance unevenness reducing unit 14, and the transmission film 15.

  The illumination optical system 30 includes a concave lens or the like, and adjusts the illumination light C emitted from the illumination device 10 to a size corresponding to the display element 40.

  The display element 40 is composed of a DMD (Digital Micro-mirror Device) having a plurality of movable micromirrors, and each mirror is controlled to be either on or off so that illumination from the illumination device 10 can be achieved. The light C is spatially modulated and an image M is generated on the screen 60 via the projection optical system 50.

  Electrodes are provided below the micromirrors in the display element 40, and each mirror is turned on or off by driving each mirror with a very short period (for example, on the order of μsec). Each mirror is movable with a hinge as a fulcrum. When the mirror is in the on state, the mirror surface tilts by a predetermined angle with the hinge as a fulcrum (for example, + 12 °), and when the mirror is in the off state, the mirror surface has the hinge. It tilts by a predetermined angle in the opposite direction as a fulcrum (for example, -12 °). The on-state mirror reflects the illumination light C from the illumination optical system 30 in the direction of the projection optical system 50, and the off-state mirror does not reflect the illumination light C in the direction of the projection optical system 50. The display element 40 projects the image M toward the projection optical system 50 by driving each mirror individually.

  The projection optical system 50 is configured by a concave lens, a convex lens, and the like, and is an optical system for efficiently projecting the display light L from the display element 40 onto the screen 60.

  The screen 60 includes a holographic diffuser, a microlens array, a diffusion plate, and the like, receives display light L from the projection optical system 50 on the back surface (lower surface in FIG. 2), and receives an image M on the front surface (upper surface in FIG. 2). Is displayed.

  The reflection optical system 70 includes a plane mirror 71 and a concave mirror 72. The plane mirror 71 reflects the display light L representing the image M displayed on the screen 60 toward the concave mirror 72. The concave mirror 72 reflects the display light L that has arrived from the plane mirror 71 toward the windshield 3. As a result, the virtual image V to be formed becomes larger than the image M displayed on the screen 60. The display light L reflected by the concave mirror 72 is transmitted through a light transmitting portion 81 described later and reaches the windshield 3.

  The housing 80 accommodates the illumination device 10, the light intensity detection unit 500, the illumination optical system 30, the display element 40, the projection optical system 50, the screen 60, the reflection optical system 70, and the like at predetermined positions. An opening is formed in the housing 80, and a translucent part 81 is provided in the opening. The translucent part 81 is made of a translucent resin such as acrylic and transmits the display light L from the concave mirror 72.

  Here, a mechanism for displaying the virtual image V by the display device 1 will be briefly described. The illumination light C emitted from the illumination device 10 is reflected by the display element 40 and projected onto the screen 60 as an image M. The display light L representing the image M displayed on the screen 60 is reflected by the plane mirror 71 and travels toward the concave mirror 72. The image M is enlarged to a predetermined size by the concave mirror 72, and the display light L representing the enlarged image M is reflected by the windshield 3, whereby the virtual image V of the image M is displayed in front of the windshield 3. . In this way, the display device 1 causes the observer 4 to visually recognize the image M as the virtual image V. Next, the light source driving device 5 will be described.

(Light source driving device 5)
As shown in FIG. 4, the light source driving device 5 includes a first control unit 100, a second control unit 200, a power feeding unit 300, a light source driving unit 400, a light intensity detection unit 500, and a light intensity integration unit 600. And comprising.
Each of these components is mounted or formed on a printed circuit board (not shown) other than the circuit board 12 disposed in the housing 80, for example. A part of each of the components may be provided outside the housing 80.

  The first control unit 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an interface, and the like. The CPU controls the overall operation of the display device 1 by reading and executing an operation program stored in advance in the ROM. The operation program includes a program for executing dimming control processing described later.

  The first control unit 100 acquires a video signal for displaying the image M and the required luminance SL from an ECU (Electronic Control Unit) 6 mounted on the vehicle 2. The first control unit 100 adjusts the light emission intensity of the light source unit 11 based on the acquired video signal and the required luminance SL, and displays an image M corresponding to the video signal on the display element 40 via the second control unit 200. Display. Further, the first control unit 100 can detect the start timing of a frame F, which will be described later, and can count the number of frames, for example, by detecting the falling edge of the vertical synchronization signal included in the video signal. . The first control unit 100 outputs a video signal input from the ECU 6 to the second control unit 200 via an image processing IC (Integrated Circuit) (not shown). Note that the video signal may be directly input to the second control unit 200 via the image processing IC without passing through the first control unit 100.

The first control unit 100 performs the following operation in order to drive and control the light source unit 11.
(1) The first control unit 100 generates the reference signal SA based on the required luminance SL (a signal indicating the required luminance) input from the ECU 6 to the first control unit 100, and compares the generated reference signal SA, which will be described later. Output to one input terminal of the circuit 410. Specifically, for example, the first control unit 100 is configured to correspond to a required luminance and a PWM (Pulse Width Modulation) value (a value indicating a duty ratio of a pulse signal) stored in advance in the ROM. With reference to the table data, a PWM value corresponding to the acquired required brightness SL is determined. Then, the first control unit 100 outputs a pulse signal of the determined PWM value (hereinafter also referred to as a PWM signal). This pulse signal is converted into an analog signal by a D / A (Digital to Analog) converter (not shown), and is output to the comparison circuit 410 as a reference signal SA. Further, the magnitude of the reference value indicated by the reference signal SA associated with the required brightness SL can be adjusted for each color of light emitted from the light source unit 11. Therefore, the magnitude of the reference signal SA output from the first control unit 100 to the comparison circuit 410 is varied for each subframe SF. Note that the subframe SF is a period obtained by time-dividing a period of one frame of the frame F (see FIG. 8), which is the display cycle of the image M, and as illustrated in FIG. Light of different colors is emitted from the portion 11. The frequency of the pulse signal for generating the reference signal SA output from the first control unit 100 is desirably 30 kHz or more.
(2) The first control unit 100 outputs a period signal SC that defines a period during which the light source unit 11 is driven to an input terminal of a logic circuit 420 described later via the second control unit 200. The period signal SC is an on / off signal that defines a period during which the light source unit 11 is driven within the subframe SF. While the period signal SC is on, the driving of the light source unit 11 is permitted and the period signal SC is off. During this period, the driving of the light source unit 11 is prohibited. The first control unit 100 can adjust the output of the light source unit 11 (for each of the light sources 11r, 11g, and 11b) by changing the rate at which the period signal SC is turned on in the subframe SF. The ROM of the first control unit 100 stores in advance table data configured by associating the required luminance SL with the ON ratio of the period signal SC in each of the light sources 11r, 11g, and 11b. Refers to the table data and outputs a period signal SC corresponding to the required luminance SL. Note that the period signal SC may have substantially the same (including completely the same) ON ratio in the subframes SF that can emit different colors.
(3) The first control unit 100 controls the power supply unit 300 to set a voltage to be applied to the light source unit 11.
(4) The first controller 100 controls the operation of the light intensity integrating means 600 by supplying the select signal PS and the reset signal PR to the light intensity integrating means 600 as will be described later. Further, the output intensity ratio is calculated based on the sum signal SM input from the light intensity integrating means 600, and the PWM value of the PWM signal is changed (the reference signal SA is changed) based on the calculated output intensity ratio.

  The second control unit 200 is an LSI (Large Scale Integration) that realizes a desired function by hardware, and includes, for example, an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). In addition, a memory (not shown) is connected to the second control unit 200, and data for outputting the period signal SC under the control of the first control unit 100 and data from the first control unit 100 are connected to the memory. In response to data for outputting an enable signal EN (R-EN, G-EN, B-EN) for controlling the light emission timing of the light source unit 11 in accordance with the video signal, and in accordance with the video signal from the first control unit 100 Data for controlling the display element 40 are stored.

  The power supply unit 300 includes a power supply IC (Integrated Circuit), a switching circuit using a transistor, and the like. The power supply unit 300 drops power from a battery (not shown) of the vehicle 2 and applies a voltage having an appropriate value to the light source unit 11 under the control of the first control unit 100. The power supply means 300 is connected to the anode side of the light sources 11r, 11g, and 11b as shown in FIG. The power feeding unit 300 may be integrated with an LSI of the light source driving unit 400 described later.

The light source driving unit 400 is an LSI that realizes a desired function by hardware, and includes, for example, an ASIC or FPGA independent of the second control unit 200.
The light source driving unit 400 includes a comparison circuit 410, a logic circuit 420, and a switch unit 430. The light source driving unit 400 acquires a light intensity detection signal SFB indicating the light intensity of each color of R, G, B in the light emitted from the light source unit 11 from the light intensity detection unit 500. Then, the light source driving unit 400 generates a driving signal SD for driving the light source unit 11 from the acquired light intensity detection signal SFB, and turns on / off the switching unit 430 based on the generated driving signal SD. Each light source 11r, 11g, 11b which comprises the light source part 11 is turned on or off.

  The comparison circuit 410 includes a comparator, compares the light intensity detection signal SFB acquired from the light intensity detection unit 500 with the reference signal SA acquired from the first control unit 100, and compares the comparison signal as a comparison result. SB is output to the logic circuit 420.

  As shown in FIGS. 6B and 6C, when the light intensity detection signal SFB (light intensity) is equal to or lower than the reference signal SA (reference value), the comparison signal SB indicating ON as a comparison result is sent to the logic circuit 420. Output. On the other hand, when the light intensity detection signal SFB (light intensity) is larger than the reference signal SA (reference value), the comparison circuit 410 outputs a comparison signal SB indicating OFF as a comparison result to the logic circuit 420. In FIG. 6, “r” corresponds to the red light R and “r” corresponds to the green light G in the reference signal SA, the light intensity detection signal SFB, the period signal SC, and the drive signal SD. “g” and the index corresponding to the blue light B are attached with an index “b”.

  As shown in FIG. 5, the logic circuit 420 includes an AND circuit 421, a red AND circuit 422, a green AND circuit 423, and a blue AND circuit 424.

  The AND circuit 421 is a drive signal SD that is an AND signal of the comparison signal SB from the comparison circuit 410 (see FIG. 6C) and the period signal SC from the second control unit 200 (see FIG. 6D). (FIG. 6E) is output to the AND circuits 422, 423, and 424 for each color.

The red AND circuit 422 outputs a red drive signal SDR that is an AND signal of the red enable signal R-EN from the second control unit 200 and the drive signal SD from the AND circuit 421 to the red switch means 431. . The green AND circuit 423 outputs a green drive signal SDG that is an AND signal of the green enable signal G-EN from the second control unit 200 and the drive signal SD from the AND circuit 421 to the green switch unit 432. . The blue AND circuit 424 outputs a blue drive signal SDB that is an AND signal of the blue enable signal B-EN from the second control unit 200 and the drive signal SD from the AND circuit 421 to the blue switch unit 433. .
Each color drive signal SDR, SDG, SDB can be understood with reference to FIG. 6 (a) showing each color enable signal and FIG. 6 (e) showing the drive signal SD from the AND circuit 421. ) Corresponding to the ON period of each color enable signal R, G, B-EN.

  The switch means 430 is formed of a switching circuit using, for example, an n-type channel or p-type channel FET (Field Effect Transistor). The switch unit 430 performs an on / off operation according to each color drive signal SDR, SDG, SDB output from the logic circuit 420.

  As shown in FIG. 4, the switch means 430 includes a red switch means 431 connected to the cathode side of the red light source 11r, a green switch means 432 connected to the cathode side of the green light source 11g, and the blue light source 11b. Blue switch means 433 connected to the cathode side.

  The red switch means 431 corresponding to the red light source 11r is turned on when the output (red drive signal SDR) of the red AND circuit 422 is turned on, whereby the drive current IR is supplied to the red light source 11r, and the red switch means 431 is turned on. The light source 11r emits red light R. On the other hand, when the output of the red AND circuit 422 is off, the red light source 11r is turned off. Similarly, the green light source 11g emits green light G when the output (green drive signal SDG) of the green AND circuit 423 corresponding to the green light source 11g is on, and the green light source 11g is turned off when it is off. Similarly, the blue light source 11b emits blue light B when the output (blue drive signal SDB) of the blue AND circuit 424 corresponding to the blue light source 11b is on, and the blue light source 11b is turned off when it is off.

  As described above, the light source driving unit 400 generates the drive signal SD (the red drive signal SDR, the green drive signal SDG, and the blue drive signal SDB) from the light intensity detection signal SFB acquired from the light intensity detection unit 500. By performing feedback control for driving each color light source 11r, 11g, 11b based on the drive signal SD, monitoring control is performed so that the light source unit 11 has a desired light emission intensity. Further, as the light source driving means 400 performs the above operation, as shown in FIG. 6 (f), the light emission timings determined by the enable signals R, G, and B-EN are respectively supplied to the light sources 11r, 11g, and 11b. Accordingly, drive currents IR, IG, and IB are supplied. In this way, the light source driving unit 400 realizes the control by the field sequential color system in which the light sources 11r, 11g, and 11b of different colors are sequentially turned on for each subframe SF.

  The light intensity detection unit 500 includes, for example, a light receiving element having a photodiode, receives the illumination light C (light RGB) from the light source unit 11, and detects the light intensities of the lights R, G, and B in a time division manner. The light intensity detection unit 500 outputs a light intensity detection signal SFB (voltage signal) indicating the detected light emission intensity to each of the comparison circuit 410 and the light intensity integration means 600.

  As shown in FIG. 7, the light intensity integrating means 600 includes an integrating circuit 610, a switch unit 620, a target color selecting unit 630, and an A / D (Analog to Digital) converter (not shown). A sum signal SM indicating the sum of light intensity indicated by the light intensity detection signal SFB input from the detection unit 500 in a predetermined period is supplied to the first control unit 100.

  The integrating circuit 610 includes an operational amplifier 611 that integrates the input light intensity detection signal SFB and outputs a sum signal SM to the first control unit 100, a resistor 612, and a capacitor 613. The light intensity detection signal SFB from the light intensity detection unit 500 is input to one input terminal of the operational amplifier 611 via the resistor 612. The other input terminal of the operational amplifier 611 is connected to the ground. The capacitor 613 has one end connected to one input terminal of the operational amplifier 611 and the other end connected to the output terminal of the operational amplifier 611.

  The switch unit 620 is composed of an analog switch, for example, and is connected in parallel with the capacitor 613. When the reset signal PR supplied from the first control unit 100 is turned off (low level), the switch unit 620 enters an off state in which one input terminal and the output terminal of the operational amplifier 611 are disconnected. Then, the operational amplifier 611 integrates the input light intensity detection signal SFB and outputs the sum signal SM from the output terminal. On the other hand, when the reset signal PR supplied from the first control unit 100 is turned on (high level), the switch unit 620 is turned on to connect the input terminal and the output terminal of the operational amplifier 611 and stored in the capacitor 613. Discharge the charge.

  That is, when the reset signal PR is turned off and the switch unit 620 is in the off state, the charge amount by the light intensity detection signal SFB is integrated over time, and the integrated value indicated by the sum signal SM increases with time. At this time, the amount of charge (voltage) indicated by the sum signal SM is T at the time T when the time from when the reset signal PR is turned on to off is T, the resistance of the resistor 612 is R, and the capacitance of the capacitor 613 is C. The sum signal SM indicates a light intensity that is (T / C · R) times the light intensity detection signal SFB.

  On the other hand, when the reset signal PR is turned on and the switch unit 620 is turned on, the voltage of the sum signal SM is forced to 0 V and reset. The timing at which the reset signal PR supplied from the first control unit 100 is turned on, that is, the start timing of the charge discharge by the switch unit 620 is performed within the non-display period. The non-display period is a period in which the first control unit 100 turns off the light source unit 11 and does not cause the display element 40 to generate the image M in the frame period (frame F). The frame period includes a display period in which the first control unit 100 turns on the light source unit 11 and causes the display element 40 to generate the image M, and the non-display period. In this way, in the frame F following the charge discharge, the charge corresponding to the light intensity detection signal SFB can be appropriately stored in the integration circuit 610.

  The target color selection unit 630 includes, for example, a switching element using a FET or a logic circuit, and is provided between the light intensity detection unit 500 and the integration circuit 610. The target color selection unit 630 corresponds to the light intensity of any color among the light intensities of the R, G, and B colors included in the light intensity detection signal SFB in accordance with the select signal PS supplied from the first control unit 100. Whether to supply the light intensity detection signal SFB to the integration circuit 610 is selected. For example, the target color selection unit 630 can acquire the enable signal EN, and when the select signal PS and the enable signal EN are both turned on (high level), the light intensity detection signal FB is integrated into the integration circuit 610. Output to. Taking the red light R as an example, when both the red enable signal R-EN and the select signal PS are turned on, the light intensity detection unit 500 and the integration circuit 610 are connected to obtain the red light intensity. A light intensity detection signal SFB (SFBr) shown is output to the integration circuit 610. As a result, as shown in FIG. 8, the charge Q corresponding to the light intensity detection signal SFB can be stored in the capacitor 613 of the integration circuit 610 at the timing when the red light R is emitted.

  Of the drive current “I” schematically shown in FIG. 8, the period when “R” rises is within the period when R-EN shown in FIG. 6 is on (that is, red light R can be emitted). Corresponds to a period during which the period signal SCr is turned on. Further, the period during which “G” rises is the period during which the period signal SCg is turned on within the period when G-EN shown in FIG. 6 is turned on (that is, within the subframe SF capable of emitting green light G). It corresponds to. Further, the period in which “B” rises is the period in which the period signal SCb is turned on in the period in which B-EN shown in FIG. 6 is turned on (that is, in the subframe SF capable of emitting blue light B). It corresponds to.

  In this embodiment, as an example, as shown in FIG. 8, the light intensity integrating means 600 outputs the light intensity by turning off the reset signal PR in a period twice as long as the frame F (a period corresponding to two frames). A sum signal SM obtained by integrating the detection signal SFB for two frames is output. That is, the charge Q stored in the capacitor 613 of the integrating circuit 610 increases with time within a period of two frames, as schematically shown in FIG. Then, when the period of two frames is completed, the first control unit 100 sends the A / D conversion request signal RQ to the A / D converter of the light intensity integrating means 600, thereby obtaining the digital value of the sum signal SM. get. Further, when acquiring the digital value of the sum signal SM, the first control unit 100 sends an A / D conversion completion signal CP to the A / D converter. For example, when the first control unit 100 acquires the value of the sum signal SM corresponding to the red light R, the value corresponding to the emission intensity QR shown in FIG. 8 is acquired.

  The configuration of the display device 1 is as described above. In this embodiment, the first control unit 100 executes dimming control based on the sum signal SM acquired from the light intensity integration unit 600, for example, so that the light emission intensity of the light source unit 11 is small in the low luminance control mode. Even if it becomes too much, accurate light control (especially, color control for adjusting the color mixture ratio of R, G, and B) can be performed. Hereinafter, the dimming control process for realizing the dimming control will be described with reference to the flowcharts of FIGS. 9 and 10. The dimming control process is continuously executed when the display device 1 is activated, and is repeatedly executed by the first control unit 100 at a predetermined cycle (for example, frame F). In the following, in order to facilitate understanding of the description, it is assumed that the flow starts from charging of the charge Q by the light intensity detection signal FB corresponding to the red light R as shown in FIG.

  The first control unit 100 acquires the required luminance SL from the ECU 6 (step S1), and determines whether or not the acquired required luminance SL is equal to or less than a threshold value stored in advance in the ROM (step S2). When the required brightness SL is equal to or lower than the threshold value (step S2; Yes), since the outside environment can be regarded as dark, the mode is shifted to the low brightness control mode, and the first control unit 100 executes the processes after step S3. . On the other hand, when the external light intensity is larger than the threshold value (step S2; No), the process returns to step S1.

  When the required luminance SL is equal to or less than the threshold (step S2; Yes) and the mode is changed to the low luminance control mode, the first control unit 100 increments a frame counter provided in the RAM, for example, by 1 (step S3). The frame counter is for determining whether or not the charge Q is charged by the light intensity detection signal SFB. The first control unit 100 refers to the frame counter as will be described later, so that the current charge Q is stored in the light intensity integrating means 600 (a period corresponding to two frames) or is discharged (immediately after the two frames). It is possible to determine whether or not the time period is within a frame.

  Subsequently, the first control unit 100 determines whether or not the value of the frame counter is “3” (step S3). When the value of the frame counter is not “3” (step S <b> 3; No), that is, when the frame counter is “1” or “2”, the first control unit 100 charges the light intensity integrating means 600. Is stored (step S5). Specifically, the first control unit 100 supplies the selection signal PS indicating the target color to the target color selection unit 630 so that the light intensity signal SFB of the target color is input to the integration circuit 610 and the switch unit 620. By setting the reset signal PR supplied to the low level (off state), the integration circuit 610 stores the charge Q by the light intensity signal SFB of the target color. As a result, as shown in FIG. 8, the total amount of charge Q stored in the integration circuit 610 increases every time light of the target color is emitted within a period of two frames.

  On the other hand, when the value of the frame counter is “3” (step S4; Yes), it can be considered that the charge period of the charge Q for two frames has ended. The digital value (charge data) of the sum signal SM from is acquired (step S6). The charge data acquired when the target color is red corresponds to the charge data (emission intensity) QR shown in FIG. Note that, as described above, the first control unit 100 acquires the digital value of the sum signal SM by sending the A / D conversion request signal RQ to the A / D converter of the light intensity integrating means 600, and acquires the digital value. In response, an A / D conversion completion signal CP is sent to the A / D converter.

  Subsequently, for example, the first control unit 100 stores the charge data for each color in a charge data storage area provided in the RAM (step S7), and initializes the frame counter to “0” (step S8).

  Subsequently, the first control unit 100 executes a charge target color selection process for selecting a target color to be charged with the charge Q (step S9).

  In the charge target color selection process, as shown in FIG. 10, first, the first control unit 100 determines whether or not the current target color is R (red) (step S91). (Step S91; Yes), the selection signal PS for setting the target color to G (green) is output to the target color selection unit 630 (step S92).

  When the current target color is not R (step S91; No), the first control unit 100 determines whether or not the current target color is G (step S93). If the current target color is G (step S93; Yes), a select signal PS for setting the target color to B (blue) is output to the target color selection unit 630 (step S94). On the other hand, if the current target color is not G (step S93; No), the first control unit 100 outputs a select signal PS with the target color as R to the target color selection unit 630 (step S95) and stores it in the RAM. The charge data satisfaction flag thus set is set to the on state (step S96). The above is the charge target color selection process.

  Returning to FIG. 9, following the execution of the charge target color selection process (step S <b> 9), the first control unit 100 discharges the light intensity integrating unit 600 by setting the reset signal PR to a high level (ON state). An instruction is given to discharge the charge Q stored in the capacitor 613 (step S10).

  After executing the process of step S5 or S10, the first control unit 100 determines whether or not the charge data satisfaction flag is in an on state (that is, whether or not the charge data for each color is available) (step S11). .

If the charge data fulfillment flag is in an off state, that is, if the charge data for each color is not yet ready (step S11; No), the process returns to step S1. Here, a period of three frames is required until the first control unit 100 acquires the charge data corresponding to one target color and discharges the charge corresponding to the charge data. Therefore, a period of 9 frames is required until the charge data for each color of R, G, and B is collected. Therefore, the process before step S11 is repeatedly executed until the light control process is started and the period of the ninth frame is reached.
On the other hand, when the charge data of each color is prepared (step S11; Yes), the first control unit 100 clears the charge data satisfaction flag to an off state (step S12).

Subsequent to step S12, the first control unit 100 calculates the output intensity ratio of each color based on the charge data of each color R, G, B stored in the charge data storage area provided in the RAM (step S13). .
Here, if the emission intensity indicated by the charge data corresponding to the red light R is QR, the emission intensity indicated by the charge data corresponding to the green light G is QG, and the emission intensity indicated by the charge data corresponding to the blue light B is QB, The first control unit 100 obtains (R output: G output: B output) = (QR / QG: 1: QR / QG) by using the emission intensity QG as a reference. The reason why the light emission intensity QG is used as a reference is that when attention is paid to the luminance of each color light, green light G> red light R> blue light B is satisfied, and the green light G is dominant over the entire luminance of the illumination light C. This is because. When obtaining the output intensity ratio, each of the emission intensities QR, QB, and QG may not be divided by the charge period (a period of two frames in this embodiment). This is because the charge period of each color is common, and the output intensity ratio calculated as a result is the same whether or not each of the emission intensities QR, QB, and QG is divided by the charge period.

  Subsequently, the first control unit 100 acquires a target output intensity ratio of each color of R, G, and B, which is stored in advance in the ROM (Step S14). This target output intensity ratio is, for example, a value already stored at the time of shipment of the display device 1 as a value for obtaining an ideal color mixture ratio (white balance).

  Subsequently, the first control unit 100 determines whether or not the output intensity ratio calculated in step S13 is equal to the target output intensity ratio acquired in step S14 (step S15). Yes) Since it can be considered that the target white light is being output, the color matching is completed (step S16).

  On the other hand, when the calculated output intensity ratio is not equal to the target output intensity ratio (step S15; No), the first control unit 100 outputs R and G to the light source driving unit 400 so as to approach the target output intensity ratio. , B (the value indicating the duty ratio) of the PWM signal corresponding to each B is changed (that is, the reference signal SA corresponding to each of R, G, B is changed) (step S17). At this time, the first control unit 100 changes the PWM value of each color by the amount of change set in the ROM in advance so that the output intensity ratio calculated in step S13 gradually approaches the target output intensity ratio. Control. That is, the light emission control is performed so that the output intensity ratio (color mixture ratio) of each color light gradually approaches the target output intensity ratio until it is determined Yes in step S15. By doing so, it is possible to prevent the observer 4 from feeling uncomfortable due to a sudden change in color and brightness in the image M. The dimming control process according to the first embodiment has been described above.

  According to the first embodiment that executes the above dimming control processing, even if the light emission intensity of the light source unit 11 becomes too low in the low luminance control mode, the sum of the light emission intensity for a predetermined period is calculated. Since the output intensity ratio is adjusted based on the total signal SM shown, it is possible to perform light adjustment control with high accuracy (particularly color adjustment control for adjusting the color mixture ratio of R, G, and B).

(Modification)
In the above, the example in which the light intensity integrating means 600 is configured to be shared by each color of R, G, and B has been shown, but may be provided independently for each color of R, G, and B. Specifically, for example, three circuits constituting the light intensity integrating means 600 are provided for each color of R, G, and B, and these color circuits are provided between the light intensity detecting unit 500 and the first control unit 100. In parallel. In the first embodiment described above, a period of 9 frames is required until the charge data of R, G, and B colors are collected. According to the modification in which the light intensity integrating means 600 for each color is provided, FIG. As shown in the figure, since the charge data of each color of R, G, and B can be aligned in three frames, it is possible to perform toning control at an early stage.
The dimming control processing according to this modification can be realized by the same processing as the flow shown in FIG. However, since the charge Q can be charged to each of the light intensity integrating means 600 for each color within the same period, the charge target color selection process in step S9 can be omitted. Specifically, in step S9 of FIG. 9, the first control unit 100 turns on the charge data satisfaction flag similar to that in step S96, instead of executing all the flow of the charge target color selection process shown in FIG. What is necessary is just to perform a process.

(Second Embodiment)
From here, the configuration of the display device 1 according to the first embodiment is the same, but only the dimming control processing executed by the first control unit 100 is different from the first embodiment in FIGS. Explanation will be made with reference to FIG. Hereinafter, differences from the first embodiment will be mainly described.

  In the dimming control process according to the second embodiment, as shown in FIG. 12, the first control unit 100 executes the short-term correction process after the process of step S5 or S10 and before the process of step S11 ( Step S20).

  In the short-term correction process, as shown in FIG. 13, first, the output intensity ratio of each color is calculated based on the charge data of each color in the previous detection frame (step S21). In step S21, the first control unit 100 calculates the output intensity ratio of each color in the same manner as in step S13, for example, based on the charge data of each color that was prepared in the previous process. The first control unit 100 may store the output intensity ratio of each color calculated in step S13 after determining Yes in step S11 in the RAM, and read the stored output intensity ratio. Further, all of the light emission intensities at the time of calculating the output intensity ratio calculated in step S21 may not be the light emission intensity at the time of calculating the output intensity ratio in the previous step S13. For example, in step S21, “the emission intensity QR stored in the charge data storage area in the current step S7” and “the previous light emission intensity QR stored in the charge data storage area immediately after being determined Yes in the previous step S11”. The output intensity ratio may be calculated based on “light emission intensity QG” and “previous light emission intensity QB stored in the charge data storage area immediately after being determined Yes in the previous step S11”. . In other words, the charge data (light emission intensity) of each color acquired by the first control unit 100 before the process of step S21 may be used for calculation of the output intensity ratio of step S21.

  Subsequently, as in step S14, the first control unit 100 acquires a target intensity ratio of R, G, and B (step S22). Subsequently, the first control unit 100 determines whether or not the output intensity ratio calculated in step S21 is equal to the target output intensity ratio acquired in step S22 (step S23). Yes), the color matching in the short-term correction process is completed (step S24).

  On the other hand, when the calculated output intensity ratio is not equal to the target output intensity ratio (step S23; No), the first control unit 100 determines whether or not it is a sensitive luminance region (step S25). For example, the sensitive luminance region is set as a region in which the observer 4 can easily recognize the change in the low luminance control mode that is easily recognized by the observer 4 when the luminance or color of the image M changes. Specifically, when the required brightness SL is equal to or smaller than a second threshold value preset in the ROM as a value smaller than a threshold value (hereinafter referred to as a first threshold value) that is the determination reference value in step S2, The first control unit 100 determines that it is a sensitive luminance region. In the second embodiment, the second threshold value is set as the minimum luminance of each of the light sources 11r, 11g, and 11b. Note that the second threshold value may be a value smaller than the first threshold value that is a transition reference in the low luminance control mode, and how to determine the second threshold value is arbitrary depending on the purpose.

  When it is not the sensitive luminance region (step S25; No), that is, when the required luminance SL is larger than the second threshold value, the first control unit 100 sets the PWM value of each color to a predetermined change amount in the same manner as in step S17. By changing only by the amount of change (hereinafter referred to as the first change amount), the output intensity ratio calculated in step S21 is controlled stepwise so as to approach the target output intensity ratio (step S26).

  On the other hand, when it is a sensitive luminance region (step S25; Yes), that is, when the required luminance SL is equal to or lower than the second threshold, the first control unit 100 sets the PWM value of each color to be greater than the first change amount in step S26. By changing the second change amount set in advance in the ROM as a small value, the output intensity ratio calculated in step S21 is controlled stepwise so as to approach the target output intensity ratio (step S27). By doing so, it is possible to prevent the observer 4 from feeling uncomfortable due to a sudden change in color and brightness in the image M that is particularly noticeable in the vicinity of the lowest luminance region. The above is the short-term correction process. As shown in FIG. 12, the first control unit 100 executes the processes after step S11 after the short-term correction process (step S20) is executed as in the first embodiment. The dimming control process according to the second embodiment is as described above.

  As described above, in the dimming control process, according to the second embodiment in which the short-term correction process is performed before the process of step S11, the period before the charge data of each color is collected (specifically, as in the first embodiment) In such a case, the output intensity ratio (color mixture ratio) of each color light approaches the target output intensity ratio even during the period when the charge Q corresponding to each color of R, G, B is stored in the light intensity integrating means 600. Light emission control is performed. Therefore, desired color matching (toning control) can be executed in a shorter cycle than in the first embodiment.

  When it is determined No in step S15 of FIG. 12, a determination process (step S25) for determining whether or not the area is a sensitive luminance area is performed as in FIG. 13, and when it is a sensitive luminance area (step S25; Yes). ), Similarly to step S27, by changing the PWM value by a second change amount smaller than the first change amount, the calculated output intensity ratio gradually approaches the target output intensity ratio. You may make it control.

  Also in the second embodiment, as in the above modification, three circuits constituting the light intensity integrating means 600 are provided for each of the R, G, and B colors, and these color circuits are provided for the light intensity detecting unit 500. And the first control unit 100 may be configured in parallel so that the light intensity integrating means 600 may be provided independently for each of R, G, and B colors. In such a case, since the charge Q can be charged to each of the light intensity integrating means 600 for each color within the same period, the charge target color selection process in step S9 can be omitted. Specifically, in step S9 in FIG. 12, the first control unit 100 turns on the charge data satisfaction flag similar to that in step S96, instead of executing all the flow of the charge target color selection process shown in FIG. What is necessary is just to perform a process. Specifically, in the first embodiment described above, a period of 9 frames is required until the charge data of R, G, and B colors are gathered. According to the modification in which the light intensity integrating means 600 for each color is provided. For example, even during the period in which the charges Q corresponding to the respective colors R, G, and B are stored in the light intensity integrating means 600, the light emission control is performed so that the output intensity ratio (color mixture ratio) of each color light approaches the target output intensity ratio. Therefore, the toning control can be performed earlier.

(1-1) The display device 1 according to the first and second embodiments and the modified example described above includes a light source unit 11 (an example of a light emitting unit) that emits light of a plurality of colors, and an image M. Drive control means (for example, driving control of the light source unit 11 in a field sequential manner so as to emit light of different colors for each subframe period (subframe SF) obtained by time-dividing the frame period (frame F) which is a display cycle (for example, A first control unit 100, a second control unit 200, and a light source driving unit 400), a display element 40 that generates light (display light L) representing the image M based on the emitted light emitted from the light source unit 11, and an output A light intensity detection unit 500 (an example of light intensity detection means) that detects the light intensity for each color of emitted light, and a sum indicating the total light intensity in a predetermined period (for example, a period of two frames) longer than the subframe period Signal S It includes a supply light intensity to the drive control means for each color of emitted light (an example of a sum information) integrating means 600 (an example of the integration means), a. The drive control means calculates the ratio of each color of light intensity based on the sum signal SM, and drives and controls the light source unit 11 so that the calculated ratio matches the ratio of each color of the set target light intensity.
According to the display device 1, even if the light emission intensity of the light source unit 11 becomes too small, the output intensity ratio is adjusted based on the sum signal SM indicating the sum of the light emission intensity over a predetermined period. Therefore, it is possible to perform dimming control with high accuracy (particularly, toning control for adjusting the color mixture ratio of R, G, and B).

(1-2) Further, the predetermined period may be a period that is one or more times the frame period. That is, the integration period of the light intensity based on the sum signal SM is not limited to a period of two frames, and may be a period of one frame or three frames or more. Note that the predetermined period is not limited to the frame period as long as it is longer than the subframe period and has a period.

(1-3) In addition, the light intensity integrating means 600 is accumulated after the elapse of the predetermined period, and the integrating circuit 610 that accumulates the charge Q based on the light intensity detection signal SFB supplied from the light intensity detecting unit 500 for a predetermined period. And a switch unit 620 for discharging the charged charges.

(1-4) In addition, the display element 40 includes a plurality of reflection units that reflect the emitted light, and the drive control unit drives and controls the plurality of reflection units to change the reflection state of the emitted light. The display element 40 generates the image M, and the frame period is displayed while the drive control unit turns on the light source unit 11 and the display element 40 generates the image M, and the drive control unit turns off the light source unit 11 and displays. It is preferable that the device 40 has a non-display period during which the image M is not generated, and the discharge of the charge by the switch unit 620 starts in the non-display period.

(1-5) Further, the drive control means adjusts the output of the light source unit 11 step by step until the ratio of each color of the light intensity calculated based on the sum signal SM matches the ratio of each color of the target light intensity. (For example, the first control unit 100 corresponds to executing step S17 in FIGS. 9 and 12 and step S26 in FIG. 13). By doing in this way, it is possible to prevent the observer 4 from feeling uncomfortable due to a sudden change in color and brightness in the image M.

(1-6) Further, the drive control means sets the ratio of each color of the light intensity to the light having the highest luminance among the light of the plurality of colors emitted from the light source unit 11 (in the above example, the green light G). Calculated based on the intensity. By doing in this way, the unintentional luminance change at the time of toning control can be suppressed. The ratio of each color of light intensity may be calculated based on the intensity of red light R or blue light B.

(1-7) Further, as in the modification described with reference to FIG. 11, the light intensity integrating means 600 is provided for each color of the emitted light, and the sum signal SM of the emitted light is transmitted within the same predetermined period. You may make it supply to a drive control means for every color. In this way, as described above, the toning control can be executed at an early stage.

(1-8) Further, the drive control means causes the light intensity integrating means 600 to supply the sum signal SM when the required luminance SL of the emitted light is not more than a predetermined threshold value (the first threshold value). By doing in this way, even if it is a case where the emitted light intensity of the light source part 11 becomes too small in the low-intensity control area | region, accurate dimming control can be performed. Since the required luminance SL is determined according to the external light illuminance, the first control unit 100 determines that the low luminance control mode is in effect when the input external light illuminance is equal to or less than the threshold, The sum signal SM may be supplied.

(2-1) In particular, in the display device 1 according to the second embodiment and the modification thereof, the drive control means (for example, the first control unit) is performed by executing the short-term correction process (step S20) shown in FIG. 100) calculates the ratio of each color of the light intensity based on the sum signal SM in the present predetermined period, and the ratio of each color of the target light intensity is set so that the calculated ratio matches the ratio of each color of the set target light intensity. After the elapse of time, the light source unit 11 is driven and controlled, and the ratio of each color of the light intensity calculated based on the sum signal SM in the predetermined period before this time coincides with the ratio of each color of the target light intensity. The light source unit 11 is also driven and controlled.
Since this is done, even during the period before the charge data for each color is collected (specifically, the period in which the charge Q corresponding to each color of R, G, B is stored in the light intensity integrating means 600), Light emission control can be performed so that the output intensity ratio (color mixture ratio) approaches the target output intensity ratio. Therefore, desired color matching (toning control) can be executed in a shorter cycle.

(2-2) Further, when the required luminance SL of the emitted light is equal to or less than a predetermined value (the second threshold value), the drive control unit has a case where the required luminance SL is larger than the predetermined value. The output of the light source unit 11 is adjusted stepwise with a smaller change amount (for example, corresponding to the process of step S27 in FIG. 13).
Thus, for example, it is possible to prevent the observer 4 from feeling uncomfortable due to a sudden change in color or brightness in the image M that becomes particularly noticeable in the vicinity of the lowest brightness region.

  In addition, this invention is not limited by the above embodiment, its modification, and drawing. Changes (including deletion of constituent elements) can be added to the embodiments and the drawings as appropriate without departing from the scope of the present invention.

  In the example described above, the light intensity is described as the luminance, but the present invention is not limited to this. The light intensity may be a physical quantity proportional to the drive current of the light source unit 11, and may be illuminance, luminous flux, and luminous intensity.

  In the above description, an example in which the display element 40 is a DMD is shown, but the present invention is not limited to this. The display element may be a liquid crystal display element that performs a display operation using light sources of three colors R, G, and B without using a color filter.

  In the above description, the example in which the display light L is reflected by the reflection optical system 70 and reaches the windshield 3 is shown, but the present invention is not limited to this. The display light L from the screen 60 may be emitted toward the windshield 3 or the combiner dedicated to the apparatus without using such a reflective optical system.

  In the above description, an example of a vehicle on which the display device 1 is mounted is a vehicle, but is not limited thereto. The display device 1 can also be installed on other vehicles (ships, aircraft, etc.). Furthermore, it is not restricted to what is installed in a vehicle. In the above description, the head-up display device is described as an example of the display device including the light source driving device 5, but the present invention is not limited thereto. Other display devices may be used. However, since the head-up display device makes it possible to visually recognize an image superimposed on the background (landscape), in particular, considering that the emission intensity needs to be adjusted, the display device including the light source driving device 5 is a head-up display. A device is preferred.

  In the above description, in order to facilitate the understanding of the present invention, the description of known unimportant technical matters is appropriately omitted.

DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 2 ... Vehicle, 3 ... Windshield, 4 ... Observer 5 ... Light source drive device, 6 ... ECU, M ... Image, L ... Display light 10 ... Illumination device 11 ... Light source part 11r, 11g, 11b ... Light source 40 ... Display element, 60 ... Screen 100 ... First controller, 200 ... Second controller, 300 ... Power supply means 400 ... Light source drive means 410 ... Comparison circuit, 420 ... Logic circuit, 430 ... Switch means 500 ... Light intensity Detecting unit 600 ... Light intensity integrating means 610 ... integrating circuit, 611 ... operational amplifier, 612 ... resistor, 613 ... capacitor 620 ... switch unit 630 ... target color selecting unit

Claims (5)

A display device that displays an image in a field sequential manner,
A light emitting means for emitting light of a plurality of colors;
Drive control means for driving and controlling the light emitting means in a field sequential manner so as to emit light of different colors for each subframe period obtained by time-dividing a frame period which is a display period of the image;
A display element that generates light representing the image based on the emitted light emitted by the light emitting means;
A light intensity detecting means for detecting a light intensity for each color of the emitted light;
Integrating means for supplying sum information indicating the sum of the light intensities in a predetermined period longer than the subframe period to the drive control means,
The drive control means includes
The ratio of each color of the light intensity is calculated based on the total information for the predetermined period of time, and the ratio of the color of the target light intensity is set so that the calculated ratio matches the ratio of each color of the set target light intensity. Drive control of the light emitting means after elapse,
The light emitting means also in the predetermined period of this time so that the ratio of each color of the light intensity calculated based on the total information in the predetermined period before this time coincides with the ratio of each color of the target light intensity. Drive control,
A display device characterized by that. The predetermined period is a period that is one or more times the frame period.
The display device according to claim 1. The integrating means is an integrating circuit for accumulating electric charge according to the signal indicating the light intensity supplied from the light intensity detecting means for the predetermined period; a switch unit for discharging the electric charge accumulated after the elapse of the predetermined period; Comprising
The display device according to claim 1 or 2. The drive control means adjusts the output of the light emitting means stepwise until the ratio of each color of the light intensity calculated based on the total information matches the ratio of each color of the target light intensity.
The display device according to claim 1, wherein the display device is a display device. When the required luminance of the emitted light is equal to or less than a predetermined value, the drive control means outputs the output of the light emitting means with a smaller change amount than when the required luminance is larger than the predetermined value. Adjust step by step,
The display device according to claim 4.

Images