JP2008152020A - Laser light source device, image display device, monitor device and lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser light source device with which overshoot in an initial driving state of an SHG element is suppressed, an image display device, a monitor device, and a lighting device. <P>SOLUTION: The laser light source device is equipped with: a light source 11 to emit a laser beam of a fundamental wave; the SHG element 12 to convert a wavelength of the laser beam; a temperature detecting portion 14 to detect the temperature of the SHG element 12; and a temperature controlling portion 15 to control the temperature of the SHG element 12, wherein the temperature detecting portion 14 has a timing controlling portion 27 to make a temperature detection interval shorter in a stabilized driving stage of the SHG element 12 than in its initial driving stage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser light source device, an image display device, a monitor device, and an illumination device.

In general, a high-pressure mercury lamp is known as an illumination light source for a projector. However, the high-pressure mercury lamp has problems such as restrictions on the color reproducibility range, instantaneous lighting, and lifetime. Therefore, it has been proposed to use a laser light source as an illumination light source.
However, the laser light source cannot directly emit light having a short wavelength such as blue light with a sufficient amount of light. Therefore, infrared light is converted into blue light using an SHG (Second Harmonic Generation) element that converts the fundamental wave into the second harmonic.
However, since the SHG element has a narrow temperature tolerance for wavelength conversion efficiency, it is necessary to keep the temperature constant. Therefore, a laser light source device has been proposed in which the temperature of the SHG element is detected by a thermistor element or the like, and the temperature of the SHG element is made constant by temperature adjusting means such as a Peltier element based on the detection result ( For example, see Patent Document 1).
JP 2000-228552 A

  However, the following problems remain in the conventional laser light source device. That is, the temperature control of the SHG element is performed by detecting the temperature of the SHG element using a thermistor element or the like. However, since the SHG element has a heat capacity, it takes a certain amount of time to reach a temperature (assumed temperature) corresponding to the amount of heat supplied, and an error occurs between the assumed temperature and the actual temperature at the time of detection. End up. Therefore, a temperature lower than the assumed temperature is detected in the initial driving state in which the SHG element is heated to a temperature at which high wavelength conversion efficiency is obtained. The SHG element is supplied with an amount of heat corresponding to the difference between the detected temperature and the assumed temperature. Thereby, there is a problem that the SHG element is excessively heated and an overshoot is generated in which the SHG element is heated exceeding the set temperature.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a laser light source device, an image display device, a monitor device, and an illumination device that suppress overshoot in an initial driving state of an SHG element.

  The present invention employs the following configuration in order to solve the above problems. That is, a laser light source device according to the present invention includes a light source that emits fundamental laser light, a wavelength conversion element that converts the wavelength of the laser light, a temperature detection unit that detects the temperature of the wavelength conversion element, A temperature control unit that controls the temperature of the wavelength conversion element, and the temperature detection unit includes a timing control unit that shortens a temperature detection interval in a driving stable period from an initial driving period of the wavelength conversion element. To do.

In the present invention, by setting the temperature detection interval in the initial stage of driving to be longer than that in the stable driving period, the number of times of temperature detection in the initial stage of driving with a large error from the detected temperature is reduced.
That is, the wavelength conversion element requires a certain amount of time to reach a temperature corresponding to the amount of heat supplied due to the influence of the heat capacity. Therefore, if the temperature of the wavelength conversion element is detected in a short time after heating, an error occurs between the temperature corresponding to the amount of heat supplied (assumed temperature) and the actual detected temperature. In the initial stage of driving when the difference between the set temperature and the detected temperature is large, the amount of change in the amount of heat of the wavelength conversion element controlled by the temperature control unit becomes large. For this reason, an error between the detected temperature and the actual temperature becomes large at the initial stage of driving.
Therefore, the difference between the actual detection temperature and the assumed temperature is reduced by lengthening the detection interval in the initial stage of driving and sufficiently securing the time until the wavelength conversion element reaches the assumed temperature or approaches the assumed temperature. This prevents an excessive amount of heat from being supplied to the wavelength conversion element and prevents the wavelength conversion element from being heated beyond the set temperature. Therefore, overshoot in the initial stage of driving can be suppressed and the temperature control can be speeded up.
Further, in the driving stable period in which the temperature of the wavelength conversion element is in the vicinity of the set temperature, the temperature detection interval is shortened, and the number of times of temperature detection in the driving stable period in which an error from the detected temperature is small is increased. Thereby, the temperature control of the wavelength conversion element in the stable driving period can be made highly accurate.

In the laser light source device according to the present invention, the temperature detection unit may include a determination unit that determines the initial driving period and the stable driving period.
In the present invention, the discrimination unit discriminates between the driving initial stage and the driving stable period of the wavelength conversion element, and the timing control unit controls the detection interval based on this discrimination.

In the laser light source device according to the present invention, it is preferable that the determination unit determines the initial driving period and the stable driving period based on a difference between a set temperature and a detection temperature of the wavelength conversion element.
In the present invention, when the difference between the set temperature and the detected temperature becomes smaller than a predetermined value, the determination unit determines that the driving has shifted from the initial driving period to the stable driving period.

In the laser light source device according to the present invention, it is preferable that the determination unit determines the drive initial stage and the drive stable period based on a drive time of the wavelength conversion element.
In this invention, when the drive time of the wavelength conversion element has passed a predetermined time, the determination unit determines that the drive has shifted from the initial drive to the stable drive period.

  A laser light source device according to the present invention includes a light source that emits fundamental laser light, a wavelength conversion element that converts the wavelength of the laser light, a temperature detection unit that detects the temperature of the wavelength conversion element, And a temperature control unit that controls the temperature of the wavelength conversion element, and the temperature detection unit includes a timing control unit that detects the first temperature after starting the driving of the light source.

In the present invention, the temperature detection unit detects the temperature after the wavelength conversion element is heated by the laser beam, thereby reducing the difference between the actual temperature of the wavelength conversion element and the initial detection temperature, and driving the initial stage. Overshoot can be suppressed.
That is, by performing the first temperature detection by the temperature detection unit after driving the light source, the wavelength conversion element absorbs the laser beam and heats it until the first detection. As a result, the difference between the set temperature and the detected temperature at the time of the first detection becomes smaller than when the first detection is performed at the start of driving. Therefore, the amount of change in the amount of heat supplied from the temperature control unit to the wavelength conversion element is reduced. Therefore, as described above, an error occurs between the detected temperature and the actual temperature, but since the amount of change in the amount of heat caused by this error becomes small, overshoot in the initial stage of driving can be suppressed.

Further, in the laser light source device according to the present invention, the temperature control unit adjusts the temperature of the wavelength conversion element, and the control for calculating the temperature control amount by the adjustment unit from the detection result of the temperature detection unit. It is good also as having a quantity calculation part.
In the present invention, the adjustment unit adjusts the temperature of the wavelength conversion element based on the control amount calculated from the detection result by the control amount calculation unit.

In the laser light source device according to the present invention, the adjustment unit heats and cools the wavelength conversion element with the supplied power, and the control amount calculation unit calculates the amount of power to be supplied to the adjustment unit. It is good as well.
In this invention, the temperature of a wavelength conversion element is adjusted by heating and cooling a wavelength conversion element with the electric power which the adjustment part supplied.

In the laser light source device according to the present invention, it is preferable that the wavelength conversion element outputs a second harmonic of the fundamental wave.
In the present invention, the fundamental laser beam is converted into the second harmonic laser beam whose wavelength is halved by the wavelength conversion element.

In the laser light source device according to the present invention, it is preferable that the temperature detection unit includes a thermistor element whose resistance value changes according to the temperature of the wavelength conversion element.
In the present invention, the temperature of the wavelength conversion element is detected by a change in the resistance value of the thermistor element.

An image display device according to the present invention includes the laser light source device described above, a light modulation unit that modulates light emitted from the laser light source device according to an image signal, and an image formed by the light modulation unit. And projection means for projecting.
In the present invention, the occurrence of overshoot can be suppressed as described above. Therefore, the amount of light emitted from the laser light source device is stabilized, and the displayed image quality is improved.

An image display device according to the present invention includes the laser light source device described above and a scanning unit that scans light emitted from the laser light source device on a projection surface.
In the present invention, the occurrence of overshoot can be suppressed as described above. Therefore, the amount of light emitted from the laser light source device is stabilized, and the displayed image quality is improved.

According to another aspect of the present invention, there is provided a monitor apparatus comprising: the above-described laser light source apparatus; and an imaging unit that captures an image of a subject irradiated by the laser light source apparatus.
In the present invention, the occurrence of overshoot can be suppressed as described above. Therefore, the amount of light emitted from the laser light source device is stabilized, and the quality of the captured image is improved.

Moreover, the illuminating device concerning this invention is equipped with the said laser light source device, It is characterized by the above-mentioned.
In the present invention, the occurrence of overshoot can be suppressed as described above. Therefore, the amount of illumination light can be stabilized.

[First Embodiment]
Hereinafter, a first embodiment of a laser light source device according to the present invention will be described with reference to the drawings. Here, FIG. 1 is a schematic configuration diagram showing a laser light source device, FIG. 2 is a graph showing temperature dependence of wavelength conversion efficiency normalized by the SHG element, and FIG. 3 is an explanatory diagram showing temperature of the SHG element and temperature detection timing. It is.

[Laser light source device]
The laser light source device 1 according to the present embodiment is a laser light source device that converts infrared light having a wavelength of 900 nm into blue light having a wavelength of 450 nm and emits it. As shown in FIG. 1, the laser light source device 1 includes a light source 11 that emits fundamental laser light, an SHG element 12, an external resonant mirror (reflecting unit) 13, a temperature detecting unit 14, and a temperature controlling unit 15. I have.

The light source 11 includes an LD (Laser Diode) element that emits infrared light having a fundamental wave wavelength of, for example, 900 nm. The driving of the light source 11 is controlled by a driving signal supplied from the driving control unit 21. Here, the drive control unit 21 includes an AC / DC converter that converts an AC voltage into a DC voltage, a DC / DC converter that changes a voltage value, and a control circuit, and PWM (Pulse Width Modulation). ) Is supplied to the light source 11.
A reflection film 22 made of, for example, a dielectric multilayer film is provided on the emission end face of the light source 11 except for the infrared emission exit. This reflective film 22 has a high reflectance with respect to infrared light, which is the fundamental wave, and blue light converted.

The SHG element 12 is made of, for example, KNbO ₃ (potassium niobate) which is a nonlinear crystal, and converts incident infrared light having a wavelength of 900 nm into blue light having a wavelength of 450 nm, which is a second harmonic, and emits it. Here, the temperature dependence of the wavelength conversion efficiency of the SHG element 12 is shown in FIG. FIG. 2 shows the temperature dependence of the wavelength conversion efficiency normalized with the maximum conversion efficiency being 1. As shown in FIG. 2, in order to obtain a conversion efficiency of 90% or more with respect to the maximum conversion efficiency, it is necessary to control the temperature of the SHG element 12 within ± 1 ° C. with respect to the temperature at which the maximum conversion efficiency is obtained. is there.
The external resonant mirror 13 has a reflectivity of, for example, about 99% with respect to infrared light that is a fundamental wave and blue light converted.
The reflective film 22, the SHG element 12, and the external resonance mirror 13 constitute an external resonator 23.

The temperature detection unit 14 includes a thermistor element 24, a temperature calculation unit (detection result calculation unit) 25, a determination unit 26, and a timing control unit 27.
The thermistor element 24 is composed of a thermistor element having a negative characteristic in which the resistance value decreases with an increase in temperature and the resistance value increases with a decrease in temperature, for example, according to the temperature change of the SHG element 12. The resistance value changes.
The temperature calculation unit 25 calculates the temperature of the SHG element 12 from the resistance value of the thermistor element 24 when the timing signal is supplied from the timing control unit 27 and outputs the detection result to the temperature control unit 15. Yes.

  The discriminating unit 26 is smaller than a predetermined value at the initial stage of driving when the difference between the set temperature of the SHG element 12 and the temperature of the SHG element 12 calculated by the temperature calculating unit 25 is a predetermined value (for example, 1 ° C.) or more. In some cases, it is determined that the drive is stable. The determination unit 26 is configured to output the determination result to the timing control unit 27. The predetermined value is set in advance according to the heat capacity of the SHG element 12 and the characteristics of the thermistor element 24.

  The timing control unit 27 outputs a timing signal that causes the temperature calculation unit 25 to calculate the temperature of the SHG element 12 from the resistance value of the thermistor element 24 based on the determination result by the determination unit 26. Here, the timing signal output by the timing controller 27 is, for example, 2 seconds in the initial driving of the SHG element 12 and is, for example, 0.1 second in the stable driving period. The timing control unit 27 is configured to output a timing signal to the temperature calculation unit 25 simultaneously with driving of the light source 11. Note that the timing signal intervals in the initial driving period and the stable driving period are set in advance according to the heat capacity of the SHG element 12 and the characteristics of the thermistor element 24.

  Here, an error occurs between the actual detection temperature of the SHG element 12 by the temperature detection unit 14 and the temperature (assumed temperature) corresponding to the amount of heat supplied to the SHG element 12. That is, when the SHG element 12 is heated, the temperature of the SHG element 12 increases with the heating, but since the SHG element 12 has a heat capacity, the temperature of the SHG element 12 reaches a temperature corresponding to the amount of heat supplied. It takes time to change. Therefore, if the temperature detection is performed in a short time (for example, 0.1 second) without giving a sufficient time (for example, 2 minutes) after heating the SHG element 12 in order to perform the temperature detection of the SHG element 12 faster, Since the SHG element 12 is not sufficiently heated, the temperature of the SHG element 12 is detected lower than the temperature (assumed temperature) of the SHG element 12 corresponding to the amount of heat supplied. Similarly, since a delay occurs even when the SHG element 12 is cooled, the temperature is detected to be higher than the temperature of the SHG element 12 corresponding to the amount of heat deprived of the temperature of the SHG element 12.

The temperature control unit 15 includes a heater (control unit) 28 that heats and cools the SHG element 12, and a power amount calculation unit (control amount calculation unit) 29 that calculates the amount of power supplied to the heater 28. The temperature of the element 12 is controlled to be, for example, 53.5 ° C. at which the wavelength conversion efficiency is maximized.
The heater 28 generates heat according to the amount of electric power and heats the SHG element 12. Note that, as described above, the SHG element 12 has a temperature (53.5 ° C.) at which the wavelength conversion efficiency is maximized, which is sufficiently higher than room temperature. Therefore, if the amount of electric power supplied to the heater 28 is small, the SHG element 12. Will be cooled.
The power amount calculation unit 29 acquires the detection result supplied from the temperature calculation unit 25, and based on the difference between the acquired detection result and the set temperature (for example, 53.5 ° C.) of the SHG element 12, the PID control method (proportional The power amount (control amount) supplied to the heater 28 is calculated by a feedback control method combining control (Proportional Control), integral control (Integral Control), and differential control (Derivative Control).

In the laser light source device 1 configured as described above, infrared light emitted from the light source 11 enters the SHG element 12. Then, the SHG element 12 generates blue light that is the second harmonic from the infrared light, and a part thereof is emitted from the external resonant mirror 13.
Here, the temperature calculation unit 25 detects the temperature of the SHG element 12 from the resistance value of the thermistor element 24 based on the timing signal supplied from the timing control unit 27 almost simultaneously with the start of driving of the light source 11. And the electric energy calculation part 29 calculates the electric energy supplied to the heater 28 by PID control based on the difference of detected temperature and preset temperature. Then, the heater 28 generates heat according to the supplied electric energy and heats the SHG element 12.

In addition, when the difference between the detected temperature and the set temperature is equal to or greater than a predetermined value (for example, 1 ° C.), the determination unit 26 determines that the SHG element 12 is in the initial driving stage, and uses the determination result as the timing control unit 27. Output to. And the timing control part 27 outputs a timing signal to the temperature calculation part 25 at intervals of 2 seconds, for example. Thereby, the temperature calculation unit 25 detects the temperature of the SHG element 12 after 2 seconds from the driving of the light source 11, as shown in FIG. Then, the power amount calculation unit 29 calculates the power amount based on the difference between the detected temperature and the set temperature, and heats the SHG element 12 according to the power amount supplied by the heater 28.
Thereafter, the temperature calculation unit 25 detects the temperature of the SHG element 12 at intervals of 2 seconds based on the timing signal supplied from the timing control unit 27. Then, the power amount calculation unit 29 calculates the power amount based on the difference between the detected temperature and the set temperature, and heats the SHG element 12 according to the power amount supplied by the heater 28.

Incidentally, the greater the difference between the detected temperature and the set temperature, the greater the amount of change in the amount of power supplied to the heater 28. Therefore, in the initial stage of driving where the difference between the detected temperature and the set temperature is large, the amount of power supplied to the heater 28 is large. Further, as described above, an error occurs between the detected temperature of the SHG element 12 and the temperature of the SHG element 12 corresponding to the amount of heat supplied to the temperature of the SHG element 12 (assumed temperature). The initial detected temperature is estimated to be lower than the assumed temperature. As the amount of change in the amount of power supplied to the heater 28 increases, the error between the detected temperature and the assumed temperature increases. Therefore, the power amount calculation unit 29 supplies an excessive amount of power to the heater 28.
Therefore, the detection interval by the temperature detection unit 14 in the initial stage of the drive is set to 2 seconds, and the detection interval is lengthened. By sufficiently securing the time until the SHG element 12 reaches or approaches the assumed temperature, the detection temperature and the assumed temperature are The difference of becomes smaller. This prevents an excessive amount of power from being supplied to the heater 28.

  Further, when the difference between the detected temperature and the set temperature is equal to or less than a predetermined value (for example, 1 ° C.), the determination unit 26 determines that the SHG element 12 is in a stable driving period, and the determination result is used as a timing control unit. 27. Then, the timing control unit 27 outputs timing signals to the temperature calculation unit 25 at intervals of, for example, 0.1 seconds. Thereby, the temperature calculation unit 25 detects the temperature of the SHG element 12 at intervals of 0.1 seconds as shown in FIG. 3 based on the timing signal supplied from the timing control unit 27. Then, the power amount calculation unit 29 calculates the power amount based on the difference between the detected temperature and the set temperature, and heats the SHG element 12 according to the power amount supplied by the heater 28. The SHG element 12 is cooled by reducing the amount of power supplied to the heater 28 or not supplying power. As described above, by increasing the number of times of detection by the temperature detector 14, the temperature control of the SHG element 12 is performed at high speed and with high accuracy.

  As described above, according to the laser light source device 1 of the present embodiment, the temperature detection interval by the temperature detection unit 14 is set to, for example, 2 seconds in the initial stage of the drive, and is longer than the detection interval in the stable driving period. Can sufficiently secure the time until the temperature reaches or approaches the assumed temperature. Thereby, it is possible to prevent the electric power from being excessively supplied to the heater 28 and to suppress the overshoot in the initial driving. Further, the temperature detection interval in the driving stable period is shortened, and the number of temperature detections in the driving stable period with a small error from the detected temperature is increased.

[Second Embodiment]
Next, a second embodiment of the laser light source device according to the present invention will be described with reference to the drawings. Here, FIG. 4 is a schematic configuration diagram showing the laser light source device. In this embodiment, since the configuration of the temperature detection unit is different from that of the first embodiment, this point will be mainly described, and the same reference numerals are given to the components described in the above embodiment, and the description will be given. Omitted.

  In the laser light source device 30 according to the present embodiment, as shown in FIG. 4, the determination unit 32 of the temperature detection unit 31 determines that the drive has started from the start of driving of the light source 11 and before the elapse of a predetermined time. After the elapse of time, the driving stable period is determined. The predetermined time is set in advance according to the heat capacity of the SHG element 12 and the characteristics of the thermistor element 24.

In the laser light source device 30 configured as described above, the infrared light emitted from the light source 11 is converted into blue light, which is the second harmonic, in the SHG element 12, and a part thereof from the external resonant mirror 13, as described above. Let it fire.
Here, the temperature calculation unit 25 detects the temperature of the SHG element 12 from the resistance value of the thermistor element 24 based on the timing signal output from the timing control unit 42. Further, the determination unit 32 determines that the drive period from the start of driving of the light source 11 to before the elapse of a predetermined time is the drive initial stage, determines that the elapse of the predetermined time is the drive stable period, and sends the determination result to the timing control unit 27. Output. Then, the timing control unit 27 sets the interval of the timing signal output to the temperature calculation unit 25 to 2 seconds, for example, at the initial stage of driving, and to 0.1 seconds, for example, at the stable driving period.
The electric energy calculation part 29 calculates the electric energy supplied to the heater 28 by PID control based on the difference between the detected temperature and the set temperature. Then, the heater 28 generates heat according to the supplied electric energy and heats the SHG element 12.

  As described above, the laser light source device 30 according to this embodiment also has the same operations and effects as those of the first embodiment described above.

[Third Embodiment]
Next, a laser light source device according to a third embodiment of the present invention will be described with reference to the drawings. Here, FIG. 5 is a schematic configuration diagram showing the laser light source device. In this embodiment, since the configuration of the temperature detection unit is different from that of the first embodiment, this point will be mainly described, and the same reference numerals are given to the components described in the above embodiment, and the description will be given. Omitted.

As shown in FIG. 5, in the laser light source device 40 according to the present embodiment, the temperature detection unit 41 includes a thermistor element 24, a temperature calculation unit 25, and a timing control unit 42.
The timing control unit 42 is configured to output an initial timing signal to the temperature calculation unit 25 after a predetermined time has elapsed from the start of driving of the light source 11. The timing control unit 42 is configured to output timing signals at regular intervals throughout the initial driving period and the stable driving period. The predetermined time is set in advance according to the heat capacity of the SHG element 12, the amount of infrared light emitted from the light source 11, the characteristics of the thermistor element 24, and the like.

In the laser light source device 40 having the above-described configuration, the infrared light emitted from the light source 11 is converted into blue light that is the second harmonic in the SHG element 12, and a part of the light is emitted from the external resonant mirror 13. Let it fire.
Here, the temperature calculation unit 25 detects the temperature of the SHG element 12 from the resistance value of the thermistor element 24 based on the timing signal output from the timing control unit 42. At this time, as shown in FIG. 6, the timing control unit 42 does not output a timing signal to the temperature calculation unit 25 from the start of driving of the light source 11 until a predetermined time. The SHG element 12 absorbs infrared light emitted from the light source 11 and is heated. Therefore, when the first timing signal is supplied, the temperature of the SHG element 12 is closer to the set temperature than the driving start time. As a result, the difference between the first detected temperature by the temperature calculation unit 25 and the set temperature becomes smaller than when the first detection is performed at the start of driving.
Accordingly, the amount of change in the amount of power supplied to the heater 28 by the power amount calculation unit 29 is reduced, so that an excessive amount of power is prevented from being supplied to the heater 28.

  As described above, according to the laser light source device 40 of the present embodiment, the temperature detection unit 41 detects the temperature after the SHG element 12 is heated by the laser beam, so that the actual temperature of the SHG element 12 and the initial temperature are first detected. Since the error with respect to the detected temperature can be reduced, it is possible to suppress overshoot in the initial stage of driving.

〔projector〕
The laser light source devices 1 and 30 in the above-described embodiment are used as a light source device of a projector (image display device) 100 as shown in FIG. Here, FIG. 7 is a schematic configuration diagram showing the projector 100.
As shown in FIG. 7, the projector 100 modulates the laser light emitted from the laser light source devices 101A to 101C and the red light laser light source device 101A, the green light laser light source device 101B, and the blue light laser light source device 101C. Light valves (light modulation means) 102A to 102C, a dichroic prism 103, and a projection lens (projection means) 104 are provided. The color image light emitted from the projector 100 is projected on the screen 105.

The blue light laser light source device 101C includes the laser light source devices 1 and 30 described above.
Each light valve 102A-102C is comprised, for example by the liquid crystal device, and becomes a structure which modulates based on the image signal to which the laser beam inject | emitted from each laser light source device 101A-101C is supplied, respectively.
And between each laser light source device 101A-101C and each light valve 102A-102C, it equalizes in order to irradiate laser light uniformly to each light valve 102A-102C from each laser light source device 101A-101C. Optical systems 106A to 106C are provided. Each of the homogenizing optical systems 106A to 106C includes, for example, a hologram 107A and a field lens 107B.
The dichroic prism 103 is formed by bonding four right-angle prisms. A dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in an X shape at the interface. ing. These dielectric multilayer films combine light of three colors to form light representing a color image.
The projection lens 104 is configured to enlarge and project the color image synthesized by the dichroic prism 103 onto the screen 105.

According to the projector 100 configured as described above, the same operations and effects as described above can be obtained. Therefore, the amount of light emitted from the blue laser light source device 101C is stabilized, and the quality of the image projected on the screen 55 is improved.
The green laser light source device 101B may also be configured to emit green laser light by converting the wavelength of infrared light by the SHG element 12, similar to the blue light laser light source device 101C.
The light valves 102A to 102C, which are transmissive liquid crystal devices, are used as the light modulation means, but other light modulation means such as a reflective liquid crystal device or a digital micromirror device are used. Also good.

[Scanning image display device]
Further, the laser light source devices 1 and 30 in the above-described embodiment are also used as a light source device of a scanning image display device (image display device) 110 as shown in FIG. Here, FIG. 8 is a schematic configuration diagram showing the scanning image display device 110.
As shown in FIG. 8, the image display device 110 is emitted from a red laser light source device 111A, a green light laser light source device 111B, a blue light laser light source device 111C, a dichroic prism 112, and the laser light source devices 111A to 111C. And a MEMS (Micro Electro Mechanical Systems) mirror (scanning means) 114 that scans the emitted light toward a screen (projected surface) 113.
The blue light laser light source device 111C includes the laser light source devices 1 and 30 described above.
In this image display device 110, the emitted light from each of the laser light source devices 111 </ b> A to 111 </ b> C is guided to scan in the horizontal and vertical directions of the screen 113 by driving the MEMS mirror 114, thereby displaying an image on the screen 113. .
The scanning-type image display device 110 having the above configuration also provides the same operations and effects as described above. Therefore, the amount of light emitted from the blue laser light source device 111C is stabilized, and the quality of the image displayed on the screen 112 is improved.
The green laser light source device 111B may also be configured to emit green laser light by converting the wavelength of infrared light by the SHG element 12 in the same manner as the blue light laser light source device 111C.

[Monitor device]
The laser light source devices 1 and 30 in the embodiment described above are also used as a light source device of a monitor device 120 as shown in FIG. 9, for example. Here, FIG. 9 is a schematic configuration diagram showing the monitor device 120.
As shown in FIG. 9, the monitor device 120 includes a main body 121 and an optical transmission unit 122 connected to the main body 121.
The main body 121 is provided with laser light source devices 1 and 30 and an image sensor (imaging means) 123.
The light transmission unit 122 has a base end connected to the main body 121, a light guide 124 that guides light emitted from the laser light source devices 1 and 30 to the tip, and an image acquired from the tip to the image sensor 123. And a light guide 125 for guiding the light. Each of these light guides 124 and 125 is composed of an optical fiber bundle. In addition, the light transmission unit 122 is provided at the tip, and emits the light from the laser light source devices 1 and 30 in a state of being diffused from the tip, and the reflected light of the light emitted from the diffusion plate 126 is incident. An image lens 127.
In this monitor device 120, the light emitted from the laser light source devices 1, 30 is irradiated onto the subject from the diffusion plate 126, and the reflected light is received by the image sensor 123, thereby obtaining an image of the subject.
The monitor device 120 configured as described above also provides the same operations and effects as described above. Therefore, the amount of light irradiated to the subject from the laser light source devices 1 and 30 is stabilized, and the quality of the image obtained by the image sensor 123 is improved.

[Lighting device]
Furthermore, the laser light source devices 1 and 30 in the above-described embodiment are also used as a light source device of an illumination device 130 as shown in FIG. Here, FIG. 10 is a schematic configuration diagram showing the illumination device 130.
As shown in FIG. 10, the illumination device 130 includes laser light source devices 1 and 30 and a diffusion member 131 that diffuses light emitted from the laser light source devices 1 and 30.
The illumination device 130 configured as described above also provides the same operations and effects as described above. Accordingly, the amount of light emitted from the laser light source devices 1 and 30 is stabilized.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the above embodiment, the thermistor element is composed of a thermistor element having negative characteristics, but may be composed of a thermistor element having positive characteristics.
In the first embodiment and the second embodiment, the temperature detection unit may be configured to detect the first temperature of the SHG element after the start of driving the light source, as in the third embodiment.
In the first embodiment and the second embodiment, the determination unit is configured to perform the determination of the initial driving period and the driving stable period based on the difference from the set temperature and the time. It is good also as a structure.
Furthermore, in the first embodiment and the second embodiment, the detection intervals are equal in the initial driving period and the driving stable period, respectively, but if the detection interval in the initial driving period is longer than the detection interval in the driving stable period, It may not be equally spaced.
In the third embodiment, the detection interval is set to be equal. However, if the first temperature detection is performed after driving of the light source is started, the detection interval may not be equal.
The temperature detection interval may be set as the detection interval in the initial driving period or the stable driving period at the time of transition between the initial driving period and the driving stable period.

Further, although the temperature of the SHG element is calculated by detecting the resistance value of the thermistor element, the temperature of the SHG element may be calculated based on other detection values such as a Schottky diode or a thermocouple.
And although the SHG element is heated and cooled by the heater, the SHG element may be heated and cooled using other members such as a Peltier element.
Further, the laser light source device uses the SHG element to convert infrared light into blue light that is the second harmonic, but converts infrared light of other wavelengths into green light that is the second harmonic. For example, it may be converted into light of other wavelengths.
Moreover, although the light source which inject | emits infrared light as a fundamental wave is used, you may use the light source which inject | emits the light of another wavelength as a fundamental wave.
The fundamental wave is converted to the second harmonic by the SHG element, but the fundamental wave may be converted to other light having a different wavelength by another element.
Furthermore, although the external resonator is formed by the SHG element and the external resonance mirror, the external resonance mirror may be disposed between the light source and the SHG element.

It is a schematic block diagram which shows the laser light source device in 1st Embodiment. It is a graph which shows the temperature dependence of the wavelength conversion efficiency of a SHG element. It is explanatory drawing which shows the temperature of a SHG element, and temperature detection timing. It is a schematic block diagram which shows the laser light source device in 2nd Embodiment. It is a schematic block diagram which shows the laser light source device in 3rd Embodiment. It is explanatory drawing which shows the temperature of a SHG element, and temperature detection timing. It is a schematic block diagram which shows a projector provided with a laser light source device. It is a schematic block diagram which shows a scanning type image display apparatus provided with a laser light source device. It is a schematic block diagram which shows a monitor apparatus provided with a laser light source device. It is a schematic block diagram which shows an illuminating device provided with a laser light source device.

Explanation of symbols

1, 30, 40 Laser light source device, 11 light source, 12 SHG element (wavelength conversion element), 14, 31, 41 Temperature detection unit, 15 Temperature control unit, 24 Thermistor element, 25 Temperature calculation unit (detection result calculation unit), 26, 32 Discriminating unit, 27, 42 Timing control unit, 28 Heater (adjustment unit), 29 Power amount calculation unit (control amount calculation unit), 100 Projector (image display device), 101C, 111C Blue light laser light source device (laser) Light source device), 102A to 102C light valve (light modulation means), 104 projection lens (projection means), 110 scanning image display device (image display device), 113 screen (projected surface), 114 MEMS mirror (scanning means) , 120 monitor device, 123 imaging device (imaging means), 130 illumination device

Claims (13)

A light source that emits a fundamental laser beam;
A wavelength conversion element for converting the wavelength of the laser beam;
A temperature detector for detecting the temperature of the wavelength conversion element;
A temperature control unit for controlling the temperature of the wavelength conversion element,
The laser light source apparatus, wherein the temperature detection unit includes a timing control unit that shortens a temperature detection interval in a driving stable period from an initial driving period of the wavelength conversion element.   The laser light source device according to claim 1, wherein the temperature detection unit includes a determination unit that determines the initial driving period and the stable driving period.   The laser light source device according to claim 2, wherein the determination unit determines the drive initial period and the drive stable period based on a difference between a set temperature and a detection temperature of the wavelength conversion element.   The laser light source device according to claim 2, wherein the determination unit determines the initial driving period and the stable driving period based on a driving time of the wavelength conversion element. A light source that emits a fundamental laser beam;
A wavelength conversion element for converting the wavelength of the laser beam;
A temperature detector for detecting the temperature of the wavelength conversion element;
A temperature control unit for controlling the temperature of the wavelength conversion element,
The laser light source apparatus, wherein the temperature detection unit includes a timing control unit that detects the initial temperature after the start of driving of the light source.   The temperature control unit includes an adjustment unit that adjusts the temperature of the wavelength conversion element, and a control amount calculation unit that calculates a control amount of temperature by the adjustment unit from a detection result of the temperature detection unit. The laser light source device according to any one of claims 1 to 5. The adjustment unit performs heating and cooling of the wavelength conversion element by the supplied power,
The laser light source device according to claim 6, wherein the control amount calculation unit calculates an amount of electric power supplied to the adjustment unit.   The laser light source device according to any one of claims 1 to 7, wherein the wavelength conversion element outputs a second harmonic of the fundamental wave.   9. The laser light source device according to claim 1, wherein the temperature detection unit includes a thermistor element whose resistance value changes according to the temperature of the wavelength conversion element. 10. The laser light source device according to any one of claims 1 to 9,
Light modulating means for modulating light emitted from the laser light source device according to an image signal;
An image display apparatus comprising: a projecting unit that projects an image formed by the light modulating unit. The laser light source device according to any one of claims 1 to 9,
An image display device comprising: scanning means for scanning light emitted from the laser light source device on a projection surface The laser light source device according to any one of claims 1 to 9,
A monitor device comprising: an imaging unit that images a subject irradiated by the laser light source device.   An illumination device comprising the laser light source device according to any one of claims 1 to 9.

Images