JP2009200269A - Laser light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser light source device which can be driven under high-efficiency conditions by most suitably adjusting temperatures of individual components of a laser light source. <P>SOLUTION: A control circuit 21 controls the value of a current supplied from a power supply source 22 to a semiconductor laser element 10 based upon a detected value of optical output of a semiconductor laser 10 obtained by an optical sensor, and while thermistors 27, 28 and 29 detect temperatures of a wavelength converting element 11 and a resonator mirror 12 respectively, temperature control elements 24, 25 and 26 independently adjust the temperatures of the wavelength converting element 11 and resonator mirror 12 to adjust the quantity of emitting light. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laser light source device that controls an output light amount of a laser light source.

  In recent years, semiconductor light sources such as lasers and LEDs have attracted attention as light sources used in television devices and projector devices. In particular, since the laser light source has a narrow emission wavelength band, the use of the laser light source can greatly expand the range of colors that can be reproduced in television devices and projector devices, greatly improving the quality of displayed images. Can be expected to do.

  By the way, in the conventional television apparatus and projector apparatus, the technique which optimizes a display image quality by adjusting the output light quantity of a light source dynamically according to a display image and an environment is proposed.

  Also in a television apparatus or a projector apparatus using a laser light source, it is desirable to adjust the output light amount of the light source in order to realize a better display image quality. As a technique for adjusting the output light amount of a laser light source, Patent Document 1 discloses that the temperature of each cavity is set to a temperature active element so that the optical path length of the first resonant cavity and the optical path length of the second resonant cavity are substantially constant. And a technique for controlling the temperature of the excitation light source using a temperature active element.

  Patent Document 2 describes a technique for adjusting the resonator length of a solid-state laser medium by adjusting the temperature of the solid-state laser medium with a thermo module while detecting it with a temperature sensor.

  These conventional techniques control the temperature and the amount of supplied power so as to drive the laser light source under the most efficient conditions.

JP-A-10-93182 JP 2003-163400 A

  However, when the output light amount of the light source is dynamically controlled according to the display image and the environment as described above, it is difficult to drive the laser light source under high-efficiency conditions depending on the conventional technology. . This is because, in the prior art, the same temperature control is performed for a laser light source (solid laser unit) composed of a plurality of components.

  That is, the temperature characteristics of a semiconductor laser, a wavelength conversion element (nonlinear optical element), and a resonator mirror that are components of a general laser light source are greatly different from each other. When adjusting the amount of light output from the light source, the amount of power supplied to the semiconductor laser is changed.To emit light from the laser light source under the optimum conditions, the temperature of each component is changed according to the change in the amount of supplied power. Each needs to be adjusted optimally.

  Therefore, the present invention has been proposed in view of the above-described circumstances, and can be driven under high-efficiency conditions by optimally adjusting the temperature of each component of the laser light source. An object is to provide a laser light source device.

  In order to solve the above-described problems and achieve the object, a laser light source device according to the present invention has any one of the following configurations.

[Configuration 1]
Semiconductor laser, wavelength conversion element to which light from semiconductor laser is incident, resonator mirror to which light having passed through wavelength conversion element is incident, optical sensor for detecting light output from semiconductor laser, and power to semiconductor laser A control circuit that controls a power supply source that supplies the temperature, a thermistor that detects the temperatures of the wavelength conversion element and the resonator mirror, and a temperature control element that independently adjusts the temperatures of the wavelength conversion element and the resonator mirror, respectively. The control circuit controls the value of the current supplied from the power supply source to the semiconductor laser based on the detected value of the optical output of the semiconductor laser by the optical sensor, and the temperature of the wavelength conversion element and the resonator mirror by each thermistor. While detecting each, the temperature of these wavelength conversion elements and resonator mirrors is adjusted independently by the temperature control element to adjust the amount of emitted light And it is characterized in Rukoto.

[Configuration 2]
In the laser light source device having the configuration 1, the control circuit performs temperature management of the semiconductor laser.

  In the laser light source device according to the present invention having the configuration 1, the control circuit controls the value of the current supplied from the power supply source to the semiconductor laser based on the detected value of the optical output of the semiconductor laser by the optical sensor, While each thermistor detects the temperature of the wavelength conversion element and the resonator mirror, and the temperature of the wavelength conversion element and the resonator mirror is independently adjusted by the temperature control element, the amount of power supplied to the semiconductor laser is dynamically adjusted. Even if it is changed, the semiconductor laser can emit light under optimum conditions and its output can be controlled.

  In the laser light source device according to the present invention having the configuration 2, since the control circuit performs temperature management of the semiconductor laser, the thermal degradation of the semiconductor laser due to the temperature rise of the semiconductor laser according to the value of the current supplied to the semiconductor laser, Shortening of life can be prevented.

  That is, the present invention can provide a laser light source device that can be driven under high-efficiency conditions by optimally adjusting the temperature of each component of the laser light source.

  Hereinafter, the configuration of the laser light source device according to the present invention will be described in detail.

[First Embodiment]
FIG. 1 is a block diagram illustrating a configuration example of a general laser light source.

  As shown in FIG. 1, the laser light source in the laser light source device according to the present invention includes a semiconductor laser 10, a wavelength conversion element 11, and a resonator mirror 12, as shown in FIG.

  In this laser light source, when electric power is supplied to the semiconductor laser 10, infrared light L <b> 0 is output from the semiconductor laser 10. A part of the infrared ray L0 is incident on the wavelength conversion element (nonlinear optical element) 11, and the wavelength conversion element 11 generates visible light L1 that is the second harmonic. The visible light L1 passes through the resonator mirror 12 and is emitted.

  When the wavelengths of the infrared ray L0 and the visible ray L1 are λ0 and λ1, the relationship between the infrared ray L0 and the visible ray L1 is expressed as follows.

λ0 = 2 ・ λ1
The infrared ray L0 that has not been wavelength-converted by the wavelength conversion element 11 is reflected by the resonator mirror 12 and oscillates.

  FIG. 2 is a block diagram showing a configuration of a main part in the embodiment of the laser light source device according to the present invention.

  As shown in FIG. 2, the laser light source device according to the present invention includes a laser light source 20, a control circuit 21, and a power supply source 22. As described above, the laser light source 20 includes the semiconductor laser 10, the wavelength conversion element 11, and the resonator mirror 12.

  The laser light source 20 includes temperature control elements 24, 25, 26 and thermistors 27, 28, 29 associated with the semiconductor laser 10, the wavelength conversion element 11, and the resonator mirror 12, respectively. Each thermistor 27, 28, 29 detects the temperature of the semiconductor laser 10, the wavelength conversion element 11, and the resonator mirror 12, respectively. The temperature control elements 24, 25, and 26 adjust the temperatures of the semiconductor laser 10, the wavelength conversion element 11, and the resonator mirror 12 independently. As the temperature control elements 24, 25, and 26, for example, a heater or a Peltier element can be used.

  In this laser light source device, the control circuit 21 controls the power supply source 22 based on the input light amount adjustment signal, and controls the amount of current supplied to the laser light source 20. The control circuit 21 adjusts the amount of light output from the laser light source 20 by independently controlling the temperature control elements 24, 25, and 26.

  In order to stabilize the output light quantity, the temperature control elements 24, 25, and 26 are preferably controlled based on the detection values from the thermistors 27, 28, and 29.

  FIG. 3 is a block diagram showing the configuration of the embodiment of the laser light source device according to the present invention.

  By the way, each component 10, 11, and 12 which comprises the laser light source 20 is sensitive with respect to temperature. Therefore, the output light amount of the laser light source 20 can change due to factors such as changes in the environmental temperature.

  Therefore, as shown in FIG. 3, the laser light source device detects the amount of light output from the laser light source 20 by the optical sensor 30, and feeds back the detection result to the control circuit 21, thereby obtaining a more stable output. Can do.

  In this laser light source device, the amount of output light can be controlled by controlling the amount of power supplied to the laser light source 20 based on the detection value obtained by the optical sensor 30. In this laser light source device, when the amount of electric power supplied to the semiconductor laser 10 is changed, a thermal influence is exerted on components (the wavelength conversion element 11 and the resonator mirror 12) other than the semiconductor laser 10 accordingly. Although generated, the temperature of each component can be detected by the thermistors 28 and 29, and the temperature can be controlled independently for each component by the temperature control elements 25 and 26.

[Second Embodiment]
In the first embodiment described above, the amount of output light of the laser light source 20 is adjusted by controlling the amount of power supplied to the laser light source 20. However, controlling the amount of power supplied may lead to an increase in the circuit scale of the power supply and a deterioration in power supply efficiency. Further, in the laser light source 20, the emission wavelength may change depending on the power supply amount, the color of the output light may change, and the quality of the light may be impaired. Therefore, in the second embodiment, the amount of output power of the laser light source 20 is adjusted with the amount of power supplied to the laser light source 20 being a constant value.

  That is, the laser light source device controls the output light amount by controlling the temperature of each component (wavelength conversion element 11 or resonator mirror 12) of the laser light source 20, as will be described later. Yes.

  FIG. 4 is a graph showing the relationship between the element temperature in the wavelength conversion element 11 and the output light quantity of the second harmonic.

  As shown in FIG. 4, the wavelength conversion element 11 constituting the laser light source device according to the present invention has temperature characteristics. That is, the output of the second harmonic varies depending on the element temperature. By utilizing this temperature characteristic and actively controlling the temperature of the wavelength conversion element 11, the amount of visible light L1 that is the output light of the laser light source 20 can be adjusted.

  FIG. 5 is a block diagram showing another example of the configuration of the laser light source.

  As shown in FIG. 5, some laser light sources have a configuration different from the configuration described above. That is, as shown in FIG. 5, the laser light source 43 includes a semiconductor laser 40 and a resonator mirror 41, and a wavelength conversion element 42 is disposed outside the laser light source 43. From this laser light source 43, laser-generated infrared light L0 is output, and outside the laser light source 43, the wavelength conversion element 42 converts the infrared light L0 into visible light L1.

  Even when the laser light source 43 configured in this way is used, the output light amount can be adjusted by controlling the temperature of the wavelength conversion element 42 as described above.

  FIG. 6 is a graph showing the temperature characteristics of the resonator mirror 12. FIG. 6A shows the relationship between wavelength and transmittance, and FIG. 6B shows the relationship between temperature and peak wavelength λp.

  Next, the temperature characteristics of the resonator mirror 12 will be considered. As shown in FIG. 6A, the resonator mirror 12 has a characteristic of reflecting only light in a wavelength band centered on a specific peak wavelength λp. That is, the resonator mirror 12 is configured to oscillate by reflecting only the wavelength of the infrared ray L0 output from the semiconductor laser 10. Therefore, the resonator mirror 12 transmits the visible light L 1 generated by the wavelength conversion element 11 and outputs it from the laser light source 20.

  The wavelength width w of the wavelength band reflected by the resonator mirror 12 is often 1 nm or less.

  Then, as shown in FIG. 6B, the resonator mirror 12 changes the wavelength of the peak wavelength λp depending on the temperature.

  By utilizing the temperature characteristic of the resonator mirror 12 and actively controlling the reflection wavelength (peak wavelength λp) at the resonator mirror 12, the oscillation efficiency of the infrared ray L0 can be changed. That is, the output light quantity of the laser light source 20 can be adjusted by controlling the temperature of the resonator mirror 12.

[Third Embodiment]
Furthermore, in the laser light source device according to the present invention, the temperature of the semiconductor laser 10 can be managed by the control circuit 21.

  In the laser light source, the temperature of the semiconductor laser 10 rises according to the value of the current supplied to the semiconductor laser 10, and the semiconductor laser 10 may cause thermal deterioration or a shortened life. Therefore, by performing temperature management of the semiconductor laser 10, it is possible to prevent such thermal deterioration and shortening of the service life.

It is a block diagram which shows the structural example of a general laser light source. It is a block diagram which shows the structure of the principal part in embodiment of the laser light source apparatus which concerns on this invention. It is a block diagram which shows the structure in embodiment of the laser light source apparatus which concerns on this invention. It is a graph which shows the relationship between the element temperature in a wavelength conversion element, and the output light quantity of a 2nd harmonic. It is a block diagram which shows the other example of a structure of a laser light source. It is a graph which shows the temperature characteristic of a resonator mirror, (a) shows the relationship between a wavelength and the transmittance | permeability, (b) shows the relationship between temperature and a peak wavelength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,40 Semiconductor laser 11,42 Wavelength conversion element 12,41 Resonator mirror 20,43 Laser light source 21 Control circuit 22 Power supply source 25,26 Temperature control element 28,29 Thermistor 30 Optical sensor

Claims (2)

A semiconductor laser;
A wavelength conversion element on which light from the semiconductor laser is incident;
A resonator mirror on which light having passed through the wavelength conversion element is incident;
An optical sensor for detecting optical output from the semiconductor laser;
A control circuit for controlling a power supply source for supplying power to the semiconductor laser;
A thermistor for detecting temperatures of the wavelength conversion element and the resonator mirror, respectively.
A temperature control element that independently adjusts the temperature of the wavelength conversion element and the resonator mirror, and
The control circuit controls a value of a current supplied from the power supply source to the semiconductor laser based on a detection value of an optical output of the semiconductor laser by the optical sensor, and the wavelength conversion element and A laser light source device characterized by adjusting the temperature of the resonator mirror and adjusting the temperature of the wavelength conversion element and the resonator mirror independently by the temperature control element to adjust the amount of emitted light. The laser light source device according to claim 1, wherein the control circuit performs temperature management of the semiconductor laser.

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