JP2007005352A - Laser light source device, display, and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser light source device where the wavelength of a light source can be changed so that the conversion efficiency of a wavelength conversion element reaches the maximum or near it, and to provide a display and a projector. <P>SOLUTION: The laser light source device comprises a laser light source 12; an external resonator mirror 14 that is a mirror for reflecting light emitted from the laser light source 12 toward the laser light source 12 and forms the component of the laser resonator with the laser light source 12; the wavelength conversion element 15 for converting the wavelength of light emitted from the laser light source 12 or a laser resonator; and a wavelength-varying means such as a piezoelectric element 13 for varying the oscillation wavelength of the laser resonator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laser light source device, a display device, and a projector.

  In recent years, as the demand for miniaturization of projectors has increased, with the increase in output of semiconductor lasers and the appearance of blue semiconductor lasers, projectors or displays using laser light sources have been studied. Since the wavelength range of the light source is narrow, the color reproduction range can be greatly widened, and the size can be reduced and the number of components can be reduced. Therefore, they have great potential as next-generation display elements. Yes.

  As a light source of the display element, laser light sources of three colors of R (red), G (green), and B (blue) are necessary. For R and B, the original vibration is present in the semiconductor laser, but for G, the original vibration does not exist, and the second harmonic generated by making the infrared laser incident on the nonlinear optical element (wavelength conversion element: SHG). It is considered to use (see, for example, Patent Document 1).

Further, a wavelength tunable surface emitting laser device capable of stably varying the oscillation wavelength over a wide range has been considered (for example, see Patent Document 2).
JP 2001-267670 A Japanese Patent Laid-Open No. 11-17285

  However, Patent Document 1 discloses an example in which a wavelength conversion element (SHG) is provided on a surface emitting laser. In this example, since the light source is not an array, there is a problem that a large light emission intensity is required when light is emitted by a single light source.

  The wavelength tunable surface emitting laser device described in Patent Document 2 also varies the wavelength of one surface emitting laser, which is a very large light source when the emission intensity is insufficient or an array is formed. There is a problem. In the wavelength tunable surface emitting laser device described in Patent Document 2, the laser resonator is formed in the structure of the semiconductor substrate. In this configuration, it is considered difficult to precisely adjust the distance between the laser body and the mirror, and the manufacture thereof is not easy. Furthermore, the technique described in Patent Document 2 does not consider any configuration using a wavelength conversion element. Therefore, the techniques described in Patent Documents 1 and 2 have a problem that the wavelength of the light source (array light source) cannot be changed so that the conversion efficiency of the wavelength conversion element is maximized.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a laser light source device, a display device, and a projector that can change the wavelength of a light source so that the conversion efficiency of the wavelength conversion element is maximized or in the vicinity thereof. And
The present invention also provides a laser light source capable of changing the wavelength of each laser light source so that the conversion efficiency of the wavelength conversion element is maximized in a light source device having a plurality of laser light sources and wavelength conversion elements forming an array. An object is to provide a device, a display device, and a projector.

In order to achieve the above object, a laser light source device according to the present invention comprises a laser light source and a mirror that reflects light emitted from the laser light source toward the laser light source, and a laser resonator together with the laser light source. An external resonator mirror that constitutes an element; a wavelength conversion element that converts the wavelength of light emitted from the laser light source or the laser resonator; and a wavelength variable unit that varies the oscillation wavelength of the laser resonator. To do.
According to the present invention, the oscillation wavelength of the laser resonator can be changed by the wavelength variable means, and the wavelength of the light incident on the wavelength conversion element can be changed. Therefore, the wavelength of the output light of the laser resonator can be changed so that the conversion efficiency of the wavelength conversion element is maximized. Therefore, according to the present invention, it is possible to maintain high conversion efficiency of the wavelength conversion element, and it is possible to eliminate the wavelength variation of the light source due to manufacturing variation by initial adjustment or the like. Moreover, even when the structure of the light source changes with time and temperature, the conversion efficiency of the wavelength conversion element can be maintained high.
In the present invention, the wavelength conversion element may be disposed outside the laser light source and the external resonator mirror, or may be disposed inside the laser light source and the external resonator mirror.
Further, the wavelength variable means may change the optical path length of the laser resonator.

In the laser light source device of the present invention, a plurality of the laser light sources are arranged so as to form one or a plurality of rows on the same substrate to constitute a laser array, and the wavelength conversion element includes a waveguide It is preferable that the light source is a single structure in which light emitted from the plurality of laser light sources is incident in common.
According to the present invention, the conversion efficiency of the wavelength conversion element can be kept high while reducing the size and cost of the light source device by using the configuration of the laser array.

In the laser light source device of the present invention, a plurality of laser light sources are arranged so as to form a plurality of rows on the same substrate to form a laser array, and the wavelength conversion element is a waveguide type wavelength conversion device. And a single structure in which light emitted from the plurality of laser light sources forming the column is commonly incident, and the single structure (wavelength conversion element) is arranged for each column. Preferably it is.
According to the present invention, the conversion efficiency of the wavelength conversion element can be kept high while reducing the size and cost of the light source device by using the configuration of the laser array. In addition, since a single structure (wavelength conversion element) is arranged for each row of laser light sources, it is not necessary to forcefully increase the shape of one wavelength conversion element. Here, the waveguide type wavelength conversion element generally has a plate shape, and it is difficult to increase the thickness of the plate shape in terms of manufacturing technology. Therefore, it is possible to provide a compact and inexpensive laser light source device in which the conversion efficiency of the wavelength conversion element is always high.

Further, the laser light source device of the present invention includes a control unit that varies the oscillation wavelength of the laser resonator so that the wavelength conversion unit has a wavelength conversion efficiency of the wavelength conversion element that is a maximum value or a value close to the maximum value. It is preferable to have.
According to the present invention, the wavelength of the laser light source can be automatically changed so that the conversion efficiency of the wavelength conversion element is maximized.

In the laser light source device of the present invention, it is preferable that the wavelength tunable unit changes a distance between the laser light source and the external resonator mirror.
According to the present invention, since the wavelength variable means is arranged outside the laser light source (original vibration), a general surface emitting laser or the like can be applied as the laser light source. Therefore, it is possible to provide a laser light source device that can maintain high conversion efficiency of the wavelength conversion element while avoiding an increase in manufacturing cost and difficulty in manufacturing.

In the laser light source device of the present invention, it is preferable that the wavelength variable means includes a piezoelectric element disposed between the laser light source and an external resonator mirror.
According to the present invention, by controlling the voltage applied to the piezoelectric element, the thickness of the piezoelectric element can be controlled, and the distance between the laser light source and the external resonator mirror can be controlled. Therefore, it is possible to provide a laser light source device that can maintain high conversion efficiency of the wavelength conversion element while avoiding an increase in manufacturing cost and difficulty in manufacturing.

In the laser light source device of the present invention, the wavelength variable means may include a transparent material having a variable refractive index and disposed between the laser light source and an external resonator mirror. preferable.
The transparent material having a variable refractive index is preferably an electro-optical material having a relatively large refractive index, such as ferroelectric ceramics. Here, examples of the ferroelectric ceramic include PLZT (lanthanum-doped lead zirconate titanate).

Further, the laser light source device of the present invention includes a light amount sensor that detects a light amount of light that has been wavelength-converted by the wavelength conversion element, and a wavelength control unit that controls a variable operation of the wavelength variable unit based on an output of the light amount sensor. It is preferable to have.
According to the present invention, for example, the wavelength variable means can be feedback controlled based on the output of the light quantity sensor. Therefore, the wavelength variable means can be controlled so that the output of the light quantity sensor becomes a desired value (maximum value).

Further, in the laser light source device of the present invention, the wavelength control unit is configured to sequentially change the wavelength variable amount of the wavelength variable unit to a different variable, and the light quantity at each time when the wavelength control unit is sequentially changed. It is preferable to have a comparison unit that specifies the maximum value in the output of the sensor and a storage unit that stores the maximum value.
According to the present invention, for example, by gradually changing the wavelength of the incident light of the wavelength conversion element by the wavelength sequential change unit and observing the output of the light quantity sensor at that time, the conversion efficiency of the wavelength conversion element is maximized. The state (for example, applied voltage) of the wavelength control means at the time can be specified. Accordingly, for example, by adopting a configuration in which the applied voltage is applied to the wavelength control means when the laser light source device is turned on, the conversion efficiency of the wavelength conversion element can be maximized immediately after the power is turned on.

In the laser light source device of the present invention, the wavelength control unit periodically detects the output of the light amount sensor every time a predetermined time has elapsed, and performs the variable operation of the wavelength variable unit based on the output of the light amount sensor. It is preferable that it is controlled periodically.
According to the present invention, the wavelength of the output light of the laser resonator can be periodically changed so that the conversion efficiency of the wavelength conversion element is maximized. Therefore, even if the wavelength of the original laser light source fluctuates due to, for example, a change over time or a temperature change, the wavelength of the incident light of the wavelength conversion element can always be set to a desired value, and a high wavelength conversion efficiency state can be maintained. .

The laser light source device of the present invention includes a light amount sensor that detects a light amount of light that has been wavelength-converted by the wavelength conversion element, and a light source control unit that controls a light emission amount of the laser light source based on an output of the light amount sensor. It is preferable to have.
According to the present invention, it is possible to perform feedback control on the light emission state of the laser light source which is the original vibration. Therefore, the amount of light emitted from the laser light source device can be made constant while maintaining a state where the wavelength conversion efficiency is high.

In the laser light source device of the present invention, the light source control means periodically detects the output of the light amount sensor every time a predetermined time has elapsed, and periodically determines the light emission amount of the laser light source based on the output of the light amount sensor. It is preferable to control it automatically.
According to the present invention, the amount of light emitted from the laser light source device can be made constant even if the light emission characteristics of the original laser light source fluctuate due to, for example, changes over time or temperature. Therefore, it is possible to provide a laser light source device that operates stably and with high efficiency over a long period of time.
The wavelength control unit is configured to vary the oscillation wavelength of the laser resonator by the wavelength variable unit when the light emission amount variable operation by the light source control unit is stopped, and the light source control unit includes: The light emission amount of the laser light source may be varied when the variable operation of the oscillation wavelength of the laser resonator by the wavelength varying means is stopped.

Further, in the laser light source device of the present invention, the laser light source forms part or all of a surface emitting laser, and the wavelength variable means can be controlled independently for each laser light source or for each column. It is preferable that they are arranged.
According to the present invention, the laser light source device can be made more compact by configuring the laser array with a surface emitting laser. Further, since the wavelength can be variably controlled for each laser light source or each row of laser light sources, for example, the conversion characteristics (optimum wavelength) of the wavelength conversion element are different for each part of the wavelength conversion element or for each wavelength conversion element. Even if it exists, wavelength conversion efficiency can be made high about all the laser beams.

In order to achieve the above object, a display device of the present invention comprises the laser light source device.
According to the present invention, it is possible to provide a display device that can perform high-quality and high-quality display over a long period of time, and further achieve downsizing and low power consumption at a low cost.

The display device of the present invention includes a red light source, a green light source, a blue light source, a light combining unit that combines light from each color light source, and a scanning unit that scans the combined light and displays an image. In the scanning display device, it is preferable that at least one color light source of the light source includes the laser light source device.
According to the present invention, a high-quality, high-quality full-color display can be provided for a long period of time, and a display device that can be reduced in size and power consumption can be provided at low cost.

In order to achieve the above object, a projector according to the present invention includes the laser light source device, a light modulation device that modulates light emitted from the laser light source device, and a projection that projects light modulated by the light modulation device. And a device.
According to the present invention, a high-quality, high-quality full-color display can be provided over a long period of time, and a projector that can be further reduced in size and power consumption can be provided at low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing referred to below, the scale of each component is appropriately changed and displayed for easy understanding of the drawing.

(First embodiment)
FIG. 1 is a schematic perspective view showing an example of a laser light source apparatus according to the first embodiment of the present invention. The laser light source device 1 of this embodiment is a device that forms a light source of various devices such as a display device, an optical communication device, an audio device, and an information processing device. The laser light source device 1 includes a substrate 11, a laser light source 12, a piezoelectric element 13, an external resonator mirror 14, and a wavelength conversion element 15.

  The substrate 11 is a substrate made of, for example, a semiconductor. The laser light source 12 is a laser arranged in a row on the substrate 11. Here, the laser light source 12 may constitute a laser array (two-dimensional laser array) arranged in an array so as to form a plurality of rows on the substrate 11. As the laser light source 12, for example, a surface emitting laser is applied. The surface emitting laser emits laser light from the surface of a semiconductor substrate (substrate 11), and has a feature that the laser emission angle is equal and small. For example, the laser light source 12 may be a surface emitting laser capable of emitting infrared laser light.

  The external resonator mirror 14 is a mirror that reflects the emitted light of the laser light source 12 toward the laser light source 12 with high efficiency, and constitutes a component of the laser resonator together with the laser light source 12. That is, the laser light source 12 and the external resonator mirror 14 constitute a laser resonator. The reflectance of the external resonator mirror 14 is, for example, about 99%. As shown in FIG. 1, the external resonator mirror 14 may be a single structure that reflects the light emitted from the plurality of laser light sources 12, or may be a plurality of structures disposed for each laser light source 12. Good.

  The wavelength conversion element 15 is a nonlinear optical element that converts the wavelength of incident light. Further, the wavelength conversion element 15 receives the light emitted from the laser light source 12 and transmitted through the external resonator mirror 14, converts the wavelength, and emits the light. In other words, the wavelength conversion element 15 converts the wavelength of the light emitted from the laser resonator composed of the laser light source 12 and the external resonator mirror 14. That is, the wavelength conversion element 15 creates green laser light by converting the wavelength of the infrared laser light emitted from the laser light source 12 to about half. Here, a plate-shaped waveguide type element is used as the wavelength conversion element 15. When such a waveguide type wavelength conversion element 15 is employed, the thickness of the wavelength conversion element 15 is thin, so that it is easy to create a periodic polarization inversion structure, to easily increase the wavelength conversion efficiency, and to reduce the manufacturing cost. it can.

  Further, the wavelength conversion element 15 is configured by one single structure that is commonly used for a one-dimensional laser array formed by a plurality of laser light sources 12. The wavelength conversion element 15 is arranged so that light emitted from a plurality of laser light sources 12 forming a one-dimensional laser array is incident in common. In other words, the plate-shaped end face (bottom face) of the wavelength conversion element 15 is disposed so as to face the light emission ports of the plurality of laser light sources 12 forming one row of the one-dimensional laser array.

  Further, the wavelength conversion element 15 may be configured as a single structure arranged one by one for each column in the two-dimensional laser array formed by the plurality of laser light sources 12 (see FIG. 6). In this case, it is preferable that each wavelength conversion element 15 is arranged so that light emitted from a plurality of laser light sources 12 forming one column in the two-dimensional laser array is incident in common. That is, it is preferable that the plate-shaped end face (bottom face) of the wavelength conversion element 15 is disposed so as to face the light emission ports of the plurality of laser light sources 12 forming one row of the two-dimensional laser array. And each wavelength conversion element 15 is arrange | positioned in parallel with a fixed space | interval mutually, It is preferable to arrange | position so that a strip shape may be made.

  The piezoelectric element 13 is an element that generates mechanical strain when a voltage is applied thereto. The piezoelectric element 13 of the present embodiment is disposed between the laser light source 12 and the external resonator mirror 14. The piezoelectric element 13 is disposed at a position that does not block the light emitted from the laser light source 12. The piezoelectric element 13 expands and contracts when a voltage is applied, and the distance between the laser light source 12 and the external resonator mirror 14 is varied by the expansion and contraction. That is, due to the expansion and contraction of the piezoelectric element 13, the external resonator mirror 14 moves along the optical axis of the laser light source 12 with respect to the substrate 11. When the distance between the laser light source 12 and the external resonator mirror 14 changes, the oscillation wavelength of the laser resonator composed of the laser light source 12 and the external resonator mirror 14 changes. Therefore, the piezoelectric element 13 functions as a wavelength variable unit that changes the wavelength of the incident light of the wavelength conversion element 15.

  Accordingly, the laser light source device 1 of the present embodiment can vary the oscillation wavelength of the laser resonator by controlling the voltage applied to the piezoelectric element 13 and variably control the wavelength of incident light of the wavelength conversion element 15. Can do. Therefore, the oscillation wavelength of the laser resonator can be varied so that the wavelength conversion efficiency of the wavelength conversion element 15 is the maximum value or near the maximum value.

  As described above and shown in FIG. 1, the laser light source device 1 uses the laser light source 12 made of a surface emitting laser. However, the laser light source device 1 may be configured by using an edge-emitting laser as the laser light source 12. That is, the laser light source device 1 may be configured by combining a laser array of edge emitting lasers and a waveguide type wavelength conversion element 15.

  For example, the laser light source device 1 may have the following configuration. A plurality of edge-emitting lasers are arranged on one edge of the substrate (sub-substrate) to constitute a one-dimensional laser array. The sub-board is mounted on the plane of the main board so that the light emission direction of the one-dimensional laser array is orthogonal to the plane of the main board (corresponding to the board 11). A plurality of sub-boards may be arranged on the main board at equal intervals. The one-dimensional laser array of the sub-board may be mounted on a member that serves as both a laser mounter and a heat sink (may be an integral structure with the main board or a separate structure). This one-dimensional laser array corresponds to the plurality of laser light sources 12 shown in FIG. Other configurations can be the same as those of the laser light source device 1 shown in FIG.

  The wavelength conversion element 15 may be a waveguide type wavelength conversion element or a bulk type wavelength conversion element. Further, an optical component such as a lens (coupling lens, condensing means, etc.) may be disposed between the light emitting portion of the laser light source 12 and the end face of the wavelength conversion element 15.

(Second Embodiment)
FIG. 2 is a schematic perspective view showing an example of the laser light source device 2 according to the second embodiment of the present invention. 2, the same components as those in FIG. 1 are denoted by the same reference numerals. The laser light source device 2 of the present embodiment is different from the laser light source device 1 of the first embodiment in that the electro-optical material 16 is included.

  The electro-optic material 16 is a transparent material (or film) having a variable refractive index, and is disposed between the laser light source 12 and the external resonator mirror 14 and constitutes the wavelength variable means of the present invention. . The electro-optic material 16 is arranged so that the light emitted from the laser light source 12 can pass therethrough. The electro-optic material 16 is preferably an electro-optic material having a relatively large refractive index, and examples thereof include ferroelectric ceramics such as PLZT.

  With such a configuration, the refractive index is changed by applying a voltage to the electro-optic material (PLZT) 16, and the optical path length of the laser resonator formed by the laser light source 12 and the external resonator mirror 14 is changed. Therefore, the oscillation wavelength of the laser resonator changes. Therefore, similarly to the laser light source device 1 of the first embodiment, the laser light source device 2 of the present embodiment can adjust the oscillation wavelength of the laser resonator to a wavelength that provides optimum conversion efficiency for the wavelength conversion element 15. .

(Third embodiment)
FIG. 3 is a schematic perspective view showing an example of the laser light source device 3 according to the third embodiment of the present invention. 3, the same components as those in FIG. 2 are denoted by the same reference numerals. FIG. 4 is a block diagram showing wavelength control means that is a component of the laser light source device 3. The laser light source device 3 according to this embodiment is different from the laser light source device 2 according to the second embodiment in that the laser light source device 3 includes a half mirror 17, a light amount sensor 21, and a wavelength control unit. The wavelength control means controls the electro-optic material (wavelength variable means) 16 based on the output of the light quantity sensor 21.

  The half mirror 17 reflects a part of the light emitted from the wavelength conversion element 15 toward the light quantity sensor 21 and transmits other light. Thereby, the light quantity sensor 21 can detect the amount of light emitted from the laser light source device 3. Next, the operation of the wavelength control means shown in FIG. 4 will be described.

  An outline of the operation of the wavelength control means will be described. The wavelength control means obtains an applied voltage value of the electro-optical material 16 that maximizes the amount of light emitted from the wavelength conversion element 15 during initial adjustment of the laser light source device 3 (for example, at the time of shipment or when the power is turned on). The value is stored in the nonvolatile memory 29. When the power is turned on next time, an applied voltage having a value stored in the nonvolatile memory 29 is applied to the electro-optic material 16. Next, details of an operation example of the wavelength control means will be described.

  First, at the time of initial adjustment, the control unit 26 controls the switch 27 to output the output signal of the voltage generation unit 28 to the piezoelectric element (PLZT) voltage control unit 30. Here, the output signal of the piezoelectric element (PLZT) voltage control unit 30 can output a signal that gradually increases (or decreases) stepwise with reference to the voltage indicated by the output signal of the voltage generation unit 28. The piezoelectric element (PLZT) voltage control unit 30 performs predetermined processing or conversion on the input signal and outputs it. In other words, the piezoelectric element (PLZT) voltage control unit 30 functions as a wavelength sequential change unit that sequentially changes the wavelength variable amount of the wavelength variable means to different variables. The voltage application unit 31 applies a voltage corresponding to the signal output from the piezoelectric element (PLZT) voltage control unit 30 to the piezoelectric element (PLZT) 32. Here, the piezoelectric element (PLZT) 32 corresponds to the electro-optical material 16 in FIG. 2 (or the piezoelectric element 13 in FIG. 1). As a result, the refractive index of the electro-optic material 16 gradually changes stepwise, the optical path length of the laser resonator also changes stepwise, and the oscillation wavelength of the laser light source 12 also changes stepwise. Therefore, since the wavelength conversion efficiency in the wavelength conversion element 15 also changes gradually in steps, the amount of light received by the light quantity sensor 21 gradually changes in steps.

  The detection signal of the light quantity sensor 21 is amplified and signal processed by the amplifier signal processing unit 22, and is sequentially converted into digital data of a desired format. The digital data is sequentially stored in the light quantity value storage unit 23 and is output to the comparison circuit 24. The comparison circuit 24 compares the light amount value at a certain time point (current time) with the light amount value at the previous time point stored in the light amount value storage unit 23. That is, when the wavelength is slightly changed by the piezoelectric element (PLZT) 32, that is, the electro-optic material 16, the comparison circuit 24 compares the light amount before and after the change.

  When the current light amount value is larger than the previous light amount value, the comparison circuit 24 outputs the current light amount value to the maximum value detection unit 25. The maximum value detection unit 25 outputs the light amount value output from the comparison circuit 24 to the piezoelectric element (PLZT) voltage control unit 30. The piezoelectric element (PLZT) voltage control unit 30 increases the voltage value input from the voltage generation unit 28 by a certain value and stores it in the nonvolatile memory 29 as a new voltage value. The piezoelectric element (PLZT) voltage control unit 30 outputs the new voltage value to the voltage application unit 31.

  The above process is repeated. That is, the stepwise wavelength change, the light amount value detection for each change, the comparison in the comparison circuit 24, and the like are repeated. In this repetition, when the comparison by the comparison circuit 24 shows that the current light amount value is smaller than the previous light amount value, that is, after the light amount value increases for each repetition, the first time. When the light amount value decreases, the maximum value detection unit 25 determines that the previous light amount value is the maximum value. The light at the maximum value is light having a wavelength that maximizes the wavelength conversion efficiency of the wavelength conversion element 15. Therefore, the comparison circuit 24 and the maximum value detection unit 25 function as a comparison unit that specifies the maximum value in the output of the light amount sensor 21 when the wavelength is sequentially varied. The voltage value generated by the piezoelectric element (PLZT) voltage control unit 30 at the maximum value is stored in the nonvolatile memory 29 via the piezoelectric element (PLZT) voltage control unit 30.

  When the maximum value is determined, the control unit 26 moves the switch 27 to the nonvolatile memory 29 side. Then, the voltage value stored in the nonvolatile memory 29 is input to the piezoelectric element (PLZT) voltage control unit 30 from the next power-on. Then, a voltage corresponding to this voltage value is applied to the piezoelectric element (PLZT) 32 via the voltage application unit 31, and the laser light source 12 emits a wavelength at which the wavelength conversion efficiency of the wavelength conversion element 15 is maximized. .

  Thus, according to the laser light source device 3 of the present embodiment, the electro-optic material 16 can be feedback-controlled so that the output of the light quantity sensor 21 becomes a desired value (maximum value). Therefore, automatic control can be performed so that the wavelength conversion efficiency of the electro-optic material 16 becomes the maximum value.

  Further, the above initial setting process performed by the wavelength control unit of the laser light source device 3 may be performed periodically every elapse of a predetermined time (for example, 10 minutes). Thereby, the applied voltage to the electro-optical material 16 is “readjusted” periodically so that the wavelength conversion efficiency in the wavelength conversion element 15 becomes the maximum value. Therefore, for example, even if the wavelength of the original laser light source 12 fluctuates due to a change over time or a temperature change, the wavelength of the incident light of the wavelength conversion element 15 can always be set to a desired value, and a state in which the wavelength conversion efficiency is high is maintained. be able to.

  Further, when the laser light source device 3 is used as a light source of a video display device, it is preferable to perform the above “readjustment” using a period that does not affect the video display (for example, between frames). In this way, it is possible to readjust the wavelength conversion efficiency while displaying an image.

  In addition, when the amount of light emitted from the laser light source device 3 is not detected by the light amount sensor 21, the half mirror 17 may be moved to a position where the light emitted from the laser light source device 3 is not blocked. good.

(Fourth embodiment)
FIG. 5 is a block diagram showing an example of light source control means in the laser light source apparatus according to the fourth embodiment of the present invention. The laser light source device of the present embodiment differs from the laser light source device 3 of the third embodiment in that the laser light source 12 emits light in addition to the wavelength control means for feedback controlling the applied voltage of the piezoelectric means 13 or the electro-optical material 16. It is a point which has the light source control means which carries out feedback control of quantity. That is, the laser light source device includes a light amount sensor that detects the light amount of light that has been wavelength-converted by the wavelength conversion element, and a light source control unit that controls the light emission amount of the laser light source 12 based on the output of the light amount sensor. Next, the laser light source device will be specifically described with reference to FIG.

  The light quantity sensor 41 corresponds to the light quantity sensor 21 of FIGS. 3 and 4. In addition, the amplifier signal processing unit 42, the light amount value storage unit 44, the comparison circuit 50, the maximum value detection unit 57, the control unit 52, the switch 53, the voltage generation unit 54, the nonvolatile memory 55, and the piezoelectric element (PLZT) voltage control unit 56. The voltage application unit 58 and the piezoelectric element (PLZT) 59 are respectively an amplifier signal processing unit 22, a light quantity value storage unit 23, a comparison circuit 24, a maximum value detection unit 25, a control unit 26, a switch 27, and a voltage generator in FIG. This corresponds to the unit 28, the non-volatile memory 29, the piezoelectric element (PLZT) voltage control unit 30, the voltage application unit 31, and the piezoelectric element (PLZT) 32.

  The switch 43, the switching circuit 45, the target value 46, the comparison circuit 47 and the laser drive circuit 48 constitute light source control means for controlling the light emission amount of the laser (corresponding to the laser light source 12) 49 based on the output of the light amount sensor 41. ing. The control unit 51 controls switching between normal light amount control and wavelength control. Next, the operation of the laser light source device will be described.

  Normally, the amount of current supplied to the laser 49 is feedback-controlled based on the light amount detected by the light amount sensor 41 so that the light amount of the emitted light from the wavelength conversion element is constant. This control is called normal light quantity control. In this state, the control unit 51 selects a light amount control loop for the laser 49. That is, the control unit 51 controls the switch 43 so that the output of the switching circuit 45 is input to the comparison circuit 47. The comparison circuit 47 compares the output of the switching circuit 45 with the target value 46. Based on the comparison result, the comparison circuit 47 controls the laser drive circuit 48, and the amount of current supplied to the laser 49 is controlled. Thus, normally, the amount of light emitted from the wavelength conversion element is controlled by controlling the amount of current supplied to the laser 49.

  On the other hand, the control is performed next in addition to the normal control. For example, the feedback control for the current supply amount to the laser 49 is held every time a fixed time elapses, and the current supply amount is kept constant. Meanwhile, feedback control of the voltage applied to the wavelength variable means (such as the piezoelectric means 13 or the electro-optical material 16) shown in the third embodiment is performed.

  Specifically, the control unit 51 switches the switch 43 to select a feedback control loop for the piezoelectric element (PLZT) 59, and the conversion efficiency is maintained in the wavelength conversion element. Thereby, the output signal of the light quantity sensor 41 is transmitted to the light quantity value storage section 44 and the comparison circuit 50 through the amplifier signal processing section 42 and the switch 43. Thereafter, the wavelength control means in the laser light source device 3 of the third embodiment shown in FIG. 4 is operated, and the wavelength conversion efficiency of the wavelength conversion element is maintained high.

  Thus, according to the laser light source device of the present embodiment, in addition to the feedback control of the wavelength control means, the light emission state of the laser 49 which is the original oscillation can also be feedback controlled. Therefore, the amount of light emitted from the laser light source device can be made constant while maintaining a state where the wavelength conversion efficiency is high.

  In addition, the laser light source device of the present embodiment performs feedback control on the light emission state of the laser 49 periodically after a predetermined time has elapsed, so that the light emission characteristics of the original laser 49 fluctuate due to changes over time or temperature changes. Even so, the amount of light emitted from the laser light source device can be made constant. Therefore, it is possible to provide a laser light source device that emits light very stably and with high efficiency over a long period of time.

(Fifth embodiment)
FIG. 6 is a schematic perspective view showing an example of a laser light source device 4 according to the fifth embodiment of the present invention. In FIG. 6, the same components as those in FIG. 3 are denoted by the same reference numerals. FIG. 7 is a block diagram showing wavelength control means which is a component of the laser light source device 4. The laser light source device 4 of the present embodiment differs from the laser light source device 3 of the third embodiment in that the electro-optic materials 16a and 16b, which are wavelength variable means, are independently provided for each of the laser light source columns (12a and 12b). It is the point arrange | positioned so that control is possible.

  The laser light source row 12a is a configuration in which the laser light sources 12 are arranged in a row. In the laser light source row 12b, the laser light sources 12 are arranged in a row, and are arranged in parallel with the laser light source row 12a. The electro-optic material 16a corresponds to the electro-optic material 16 of the laser light source device 2, and is disposed so that the light from the laser light source array 12a can pass therethrough. The electro-optic material 16b corresponds to the electro-optic material 16 of the laser light source device 2, and is arranged so that the light from the laser light source row 12b is transmitted. It is assumed that the refractive index of the electro-optic material 16a and the electro-optic material 16b is separately controlled independently. Further, instead of the electro-optic materials 16a and 16b, two piezoelectric elements that are controlled independently may be arranged. The external resonator mirror 14A, the wavelength conversion elements 15a and 15b, and the light quantity sensors 81a and 81b correspond to the external resonator mirror 14, the wavelength conversion element 15, and the light quantity sensor 21 of FIG. Next, the operation of the laser light source device 4 will be described.

  The light emitted from the laser light source array 12a is transmitted through the electro-optic material 16a, and most of the light is reflected by the external resonator mirror 14A to enter a laser oscillation state. And the light which permeate | transmitted the external resonator mirror 14A among the lights radiate | emitted from the laser light source row | line | column 12a is wavelength-converted into visible light by the wavelength conversion element 15a. Part of the wavelength-converted light is reflected by the half mirror 17 and enters the light amount sensor 81a.

  The light emitted from the laser light source row 12b is transmitted through the electro-optic material 16b, and most of the light is reflected by the external resonator mirror 14A to enter a laser oscillation state. And the light which permeate | transmitted the external resonator mirror 14A among the lights radiate | emitted from the laser light source row | line | column 12b is wavelength-converted into visible light by the wavelength conversion element 15a. Part of the wavelength-converted light is reflected by the half mirror 17 and enters the light amount sensor 81b.

  Then, based on the amount of light received by the light amount sensor 81a, the refractive index of the electro-optic material 16a (that is, PLZT (1) 92a) is controlled by the wavelength control unit in FIG. That is, the light quantity sensor 81a, the amplifier signal processing section 82a, the light quantity value storage section 83a, the comparison circuit 84a, the maximum value detection section 85a, the control section 86a, the switch 87a, and the voltage generation section 88a that constitute the wavelength control means of FIG. , A nonvolatile memory 89a, a piezoelectric element (PLZT) voltage control unit 90a, a voltage application unit 91a, and a PLZT 92a are respectively a light amount sensor 21, an amplifier signal processing unit 22, a light amount value storage unit 23, a comparison circuit 24, and a maximum. The value detection unit 25, the control unit 26, the switch 27, the voltage generation unit 28, the nonvolatile memory 29, the piezoelectric element (PLZT) voltage control unit 30, the voltage application unit 31, and the piezoelectric element (PLZT) 32 are equivalent to each other.

  Further, based on the amount of light received by the light quantity sensor 81b, the refractive index of the electro-optic material 16b (that is, PLZT (1) 92b) is controlled by the wavelength control unit in FIG. 7B. That is, the light quantity sensor 81b, the amplifier signal processing section 82b, the light quantity value storage section 83b, the comparison circuit 84b, the maximum value detection section 85b, the control section 86b, the switch 87b, and the voltage generation section 88b that constitute the wavelength control means of FIG. , Nonvolatile memory 89b, piezoelectric element (PLZT) voltage control unit 90b, voltage application unit 91b, and PLZT 92b are respectively the light amount sensor 21, the amplifier signal processing unit 22, the light amount value storage unit 23, the comparison circuit 24, and the maximum in FIG. The value detection unit 25, the control unit 26, the switch 27, the voltage generation unit 28, the nonvolatile memory 29, the piezoelectric element (PLZT) voltage control unit 30, the voltage application unit 31, and the piezoelectric element (PLZT) 32 are equivalent to each other.

  As a result, the laser light source device 4 of the present embodiment can independently adjust the wavelength of incident light with the electro-optic materials 16a and 16b for each of the laser light source arrays 12a and 12b, that is, for each of the wavelength conversion elements 15a and 15b. Therefore, even when the optimum conversion wavelengths of the wavelength conversion element 15a and the wavelength conversion element 15b are different, the wavelength conversion efficiency of each of the wavelength conversion elements 15a and 15b can be maintained in a high state. Further, even when one wavelength conversion element is used instead of the wavelength conversion element 15a and the wavelength conversion element 15b and the optimum conversion wavelength differs depending on each part of the wavelength conversion element, Each conversion efficiency can be maintained at a high level.

  Further, in the laser light source device 4 of the present embodiment, even when the light emission wavelengths of the laser light source array 12a and the laser light source array 12b are different, the electro-optical materials 16a and 16b are separately independent for each light of the laser light source arrays 12a and 12b. Can be adjusted. Therefore, even in this case, the wavelength conversion efficiencies of the wavelength conversion elements 15a and 15b can be maintained at a high level. The laser light source rows 12a and 12b may be three or more rows, and the light of the plurality of laser light source rows 12a and 12b may be incident on one electro-optic material 16a and 16b. Further, two or more piezoelectric elements that are independently driven and controlled may be used instead of the electro-optic materials 16a and 16b.

(Display device)
Next, an embodiment of a display device using any of the laser light source devices of the above embodiment will be described.
FIG. 8 is a diagram showing a schematic configuration of the full-color scanning display device 100 which is the display device of the present embodiment. The scanning display device 100 includes a light source including a red light source 102, a green light source 110, and a blue light source 103, a reflection plate 103 that reflects red light, a reflection plate 104 that reflects blue light, and transmits green light. A dichroic mirror 105 that reflects red light; a dichroic mirror 106 that transmits green light and reflects blue light; a scanning mirror 107 that scans light from a light source; and a display board 108 that displays light from the scanning mirror 107 as an image. It has.

  Each of the red light source 102, the green light source 110, and the blue light source 103 is formed of any one of the laser light source devices shown in FIGS.

  The red light emitted from the red light source 102 is reflected by the reflecting plate 103 and the dichroic mirror 105, further passes through the dichroic mirror 106, and is guided to the scanning mirror 107. The blue light emitted from the blue light source 101 is reflected by the reflecting plate 104 and the dichroic mirror 106 and guided to the scanning mirror 107. Further, the green light emitted from the green light source 110 passes through the dichroic mirror 105 and the dichroic mirror 106 and is guided to the scanning mirror 107. The scanning mirror 107 performs scanning according to the image projected on the display board 108.

  According to the scanning display device 100 of the present embodiment, high-quality and high-quality full-color display can be performed over a long period of time, and further downsizing, low power consumption, low cost, and the like can be achieved.

  In the above-described embodiment of the scanning display device, an example in which the dichroic mirror is used as the light combining unit and the scanning mirror 107 is used as the scanning unit has been described. However, the configuration includes a scanning mirror for each color without the light combining unit. It is also good.

(projector)
Next, an embodiment of a projector using any of the laser light source devices of the above embodiment will be described.
FIG. 9 is a diagram showing a schematic configuration of the projector 70 according to the present embodiment, which is an example of a three-plate system. In the projector 70, an array light source 10r in which semiconductor lasers that emit red (R) color light are two-dimensionally configured in an array, an array light source 10g that emits green (G) color light, and blue (B) color light. Three array light sources 10b in which semiconductor lasers that emit light are two-dimensionally configured in an array are used as light sources.

  The array light source 10r, the array light source 10g, and the array light source 10b are each composed of any of the laser light source devices shown in FIGS.

  The light emitted from each of the array light sources 10r, 10g, and 10b is applied to the liquid crystal light valve 75. That is, a liquid crystal light valve 75 that modulates each color light of R, G, and B is provided on the emission side of each of the array light sources 10r, 10g, and 10b. Then, the three color lights modulated by the respective liquid crystal light valves 75 are configured to enter a cross dichroic prism (color combining means) 77. This prism 77 is formed by bonding four right-angle prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a cross shape on the inner surface. These dielectric multilayer films combine the three color lights Lr, Lg, and Lb to form light representing a color image. The color-synthesized light is projected onto the screen 79 by the projection lens 76 (projection device), and an enlarged image is displayed.

  According to the projector 70 of the present embodiment, high-quality, high-quality full-color display can be performed over a long period of time, and further downsizing, low power consumption, low cost, and the like can be achieved.

  In the above projector, an example is shown in which three liquid crystal light valves are used as the light modulator and a cross dichroic prism is used as the color synthesizing means. However, a semiconductor that emits each color light to the array light source without the color synthesizing means. Lasers may be arranged so that each color light is emitted in a time sequential manner, and each color light may be modulated in a time sequential manner with a single liquid crystal light valve. Further, although an example in which a transmissive liquid crystal light valve is used as the light modulation device has been described, a reflective liquid crystal light valve, DMD, or a diffraction grating light valve may be used.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the laser light source device of the present invention, an electro-optical material can be applied instead of the piezoelectric element, and a piezoelectric element can be applied instead of the electro-optical material.

It is a model perspective view which shows an example of the laser light source apparatus which concerns on 1st Embodiment of this invention. It is a model perspective view which shows an example of the laser light source apparatus which concerns on 2nd Embodiment of this invention. It is a model perspective view which shows an example of the laser light source device which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the wavelength control means in a laser light source apparatus same as the above. It is a block diagram of the light source control means of the laser light source apparatus which concerns on 4th Embodiment of this invention. It is a model perspective view which shows an example of the laser light source apparatus which concerns on 5th Embodiment of this invention. It is a block diagram which shows the wavelength control means in a laser light source apparatus same as the above. 1 is a schematic configuration diagram illustrating an example of a scanning display device according to an embodiment of the present invention. It is a schematic block diagram which shows an example of the projector which concerns on embodiment of this invention.

Explanation of symbols

1, 2, 3, 4 ... laser light source device, 11 ... substrate, 12 ... laser light source, 12a, 12b ... laser light source array, 13 ... piezoelectric element, 14, 14A ... external resonator mirror, 15, 15a, 15b ... wavelength Conversion element, 16, 16a, 16b ... electro-optic material, 17 ... half mirror, 21, 81a, 81b ... light quantity sensor

Claims (15)

A laser light source;
An external resonator mirror that reflects light emitted from the laser light source toward the laser light source and forms a component of a laser resonator together with the laser light source;
A wavelength conversion element for wavelength-converting light emitted from the laser light source or laser resonator;
A laser light source device comprising: a wavelength variable unit that varies the oscillation wavelength of the laser resonator. A plurality of the laser light sources are arranged so as to form one or a plurality of rows on the same substrate to constitute a laser array,
2. The laser according to claim 1, wherein the wavelength conversion element is a waveguide type wavelength conversion element and is a single structure into which light emitted from the plurality of laser light sources is incident in common. Light source device. A plurality of the laser light sources are arranged so as to form a plurality of rows on the same substrate to constitute a laser array,
The wavelength conversion element is a waveguide type wavelength conversion element, and is a single structure in which light emitted from the plurality of laser light sources forming the row is commonly incident,
The laser light source device according to claim 1, wherein the single structure is arranged for each row.   The wavelength conversion unit includes a control unit that varies the oscillation wavelength of the laser resonator so that the wavelength conversion efficiency of the wavelength conversion element is a maximum value or a value close to the maximum value. Item 4. The laser light source device according to any one of Items 1 to 3.   5. The laser light source device according to claim 1, wherein the wavelength varying unit is configured to vary an interval between the laser light source and an external resonator mirror. 6.   6. The laser light source device according to claim 1, wherein the wavelength variable unit includes a piezoelectric element disposed between the laser light source and an external resonator mirror.   5. The wavelength variable means according to claim 1, wherein the wavelength variable means is a transparent material having a variable refractive index, which is disposed between the laser light source and an external resonator mirror. The laser light source device according to claim 1. A light amount sensor for detecting the light amount of light wavelength-converted by the wavelength conversion element;
The laser light source device according to claim 1, further comprising: a wavelength control unit that controls a variable operation of the wavelength variable unit based on an output of the light amount sensor.   The wavelength control unit includes a wavelength sequential change unit that sequentially changes the wavelength variable amount of the wavelength variable unit to different variables, and a comparison that specifies a maximum value in the output of the light amount sensor at each of the wavelength variable units when sequentially changed. The laser light source device according to claim 8, further comprising: a storage unit that stores the maximum value.   The wavelength control means periodically detects the output of the light quantity sensor every time a predetermined time has elapsed, and periodically controls the variable operation of the wavelength variable means based on the output of the light quantity sensor. The laser light source device according to claim 8 or 9, characterized in that A light amount sensor for detecting the light amount of light wavelength-converted by the wavelength conversion element;
11. The laser light source device according to claim 1, further comprising: a light source control unit configured to control a light emission amount of the laser light source based on an output of the light quantity sensor.   The light source control means periodically detects the output of the light amount sensor after a predetermined time has elapsed, and periodically controls the light emission amount of the laser light source based on the output of the light amount sensor. The laser light source device according to claim 11. The laser light source forms part or all of a surface emitting laser,
The laser light source device according to any one of claims 1 to 12, wherein the wavelength tunable unit is arranged so as to be independently controllable for each of the laser light sources or for each of the columns.   A display device comprising the laser light source device according to any one of claims 1 to 13. 14. The laser light source device according to claim 1, a light modulation device that modulates light emitted from the laser light source device, and a projection device that projects light modulated by the light modulation device. A projector comprising:

Images