JP2008193054A - Light source device, projector device, monitor device, and lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems wherein, when the temperature of a laser beam source exceeds a tolerable temperature, the output power of a laser beam source drops sharply and a period for which the laser beam source can emit laser beam stably is shortened, in other words, the service life of the laser beam source is shortened. <P>SOLUTION: The control unit 170 of a light source device 10 obtains the temperature of the base plate of a semiconductor laser device 100a from a temperature sensor 130 as the temperature of the light source device, and adjusts an electric power value supplied from a power supply driving circuit 150a to the semiconductor laser device 100a so that the output power of the semiconductor laser device 100a will be an output power corresponding to a light source temperature. A power supply driving circuit 150a supplies power to the semiconductor laser device 100a by applying a pulse voltage to it, and adjusts the power supplied to the semiconductor laser device 100a by pulse modulation, more specifically, by modulating the width and amplitude of pulses. This prevents an increase in temperature of the semiconductor laser device, and as a result, prevent reductions in the service life of the semiconductor laser device is prevented, even when there is a failure in a cooling device that cools the semiconductor laser device, or even when the device is used in a high temperature environment not envisioned in the time of manufacturing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  2. Description of the Related Art Image display devices that display images by irradiating spatial light modulation devices such as light valves and digital mirror devices (DMDs) with illumination light from a light source device are used. In the image display apparatus, for example, a laser light source that emits laser light is used as a light source.

  The laser light source operates to generate heat, and the temperature of the apparatus main body increases with the operation time. In order to suppress shortening of the service life of the laser light source device due to temperature rise, the image display device includes, for example, a cooler that cools the laser light source.

JP-A-5-313115 JP 2006-91132 A

  However, there is a possibility that the temperature of the laser light source may exceed the allowable temperature due to the use of the image display device in an environment exceeding the allowable temperature at which the laser light source can stably operate, the failure of the cooler, or the like. When the temperature of the laser light source exceeds the allowable temperature, there is a problem that the output is drastically reduced as compared with the case where the laser light source is operating stably. Further, the higher the operating temperature of the laser light source, the shorter the period during which the laser light source can stably emit laser light, that is, the service life becomes shorter.

  The above-mentioned problem is not limited to an image display device using a laser light source device, but may also occur in a monitor device or a lighting device using a laser light source device.

  The present invention has been made in view of the above-described problems, and an object thereof is to suppress a rapid decrease in laser light source output.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A light source device that emits laser light, a drive circuit that supplies power for driving the light source, an acquisition unit for acquiring the temperature of the light source, and the acquired light source temperature is a predetermined value. And a controller that controls the drive circuit so as to reduce the power per unit time supplied from the drive circuit to the light source when higher than a first threshold.

  According to the light source device of application example 1, the power to be supplied to the light source can be reduced according to the temperature of the light source, and the temperature rise of the light source can be suppressed. Therefore, the brightness of the light output from the light source can be maintained in a short period of time without being suddenly lowered to the extent that it cannot be used.

  The light source device of Application Example 1 further includes a storage unit that stores related information that associates the light source temperature with target power that is power to be supplied to the light source, and the control unit includes the acquired light source temperature and the light source temperature. The driving circuit is controlled using related information.

  According to the light source device of Application Example 1, since the drive circuit can be controlled based on the related information, the processing speed can be improved.

  In the light source device of Application Example 1, the related information includes a target power table that associates the light source temperature with the target power, and the control unit uses the light source temperature and the target power table to configure the drive circuit. Control.

  According to the light source device of Application Example 1, since the drive circuit can be controlled using the light source temperature and the target power table, the processing speed can be improved and the processing load can be reduced with a simple configuration.

  In the light source device of Application Example 1, when the power per unit time supplied from the drive circuit to the light source is reduced, the control unit is configured such that the luminance change amount of the light source is the luminance of the light source before the power reduction. The drive circuit is controlled so as to change the power per unit time supplied to the light source so as to change the gradient to 2% or less per 1/60 second with respect to the value.

  In the light source device of Application Example 1, the control unit further compares a second threshold value lower than the first threshold value with the acquired light source temperature, and the acquired light source temperature is higher than the second threshold value. If it is lower, the drive circuit is controlled to increase the power per unit time supplied from the drive circuit to the light source.

  According to the light source device of Application Example 1, it is possible to increase the power to be supplied to the light source in accordance with the temperature decrease of the light source. Therefore, an extreme decrease in the amount of light output from the light source can be suppressed.

  Further, in the light source device of Application Example 1, when the power per unit time supplied from the drive circuit to the light source is increased, the luminance change amount of the light source is the light source before the power increase. The drive circuit is controlled so as to change the power per unit time supplied to the light source so that the gradient value changes by 2% or less per 1/60 second with respect to the luminance value.

  According to the light source device of Application Example 1, when the power per unit time supplied from the drive circuit to the light source is changed, the control unit has a luminance change amount of the light source of 1 relative to the luminance value of the light source before the change. / The power change can be controlled so that the gradient is 2% or less per 60 seconds. If the luminance change has a gradient of 2% or less per 1/60 second, the power can be adjusted without causing the observer to almost feel the luminance change. Can provide images without any discomfort.

  In the light source device of Application Example 1, the control unit controls the drive circuit so that the power per unit time supplied to the light source becomes the target power when the drive circuit is activated.

  According to the light source device of Application Example 1, the target power at the time of activation can be set with a simple configuration.

  In the light source device of Application Example 1, the control unit predicts a steady temperature at which the temperature of the light source is in a steady state using a change amount of the temperature of the light source in a predetermined time, and per unit time supplied to the light source. The drive circuit is controlled so that the luminance changes with the gradient with respect to the target power defined by the predicted steady temperature and the target power table.

  According to the light source device of Application Example 1, the power can be adjusted such that the luminance changes with a gradient of 2% or less per 1/60 second with respect to the target power corresponding to the predicted steady temperature. Therefore, the brightness of the image does not change abruptly until the steady temperature is reached, and an image that does not feel strange to the viewer can be provided.

  In the light source device of Application Example 1, when the light source temperature changes by a predetermined amount or more during a predetermined time, the control unit controls the drive circuit according to the light source temperature after the change.

  According to the light source device of Application Example 1, the target power can be changed when the light source temperature changes by a certain amount or more without a certain time. Therefore, it is possible to suppress the target power from fluctuating frequently, and to improve the operational stability of the light source device.

  In the light source device of Application Example 1, the related information includes the target power at the first temperature as the first target power, and the target power at the second temperature lower than the first temperature as the second target power. When the target power at the third temperature lower than the second temperature is set as the third target power, the first temperature with respect to the difference between the first target power and the second target power, and The ratio of the difference from the second temperature is greater than the ratio of the difference between the second temperature and the third temperature with respect to the difference between the second target power and the third target power. Including parts.

  According to the light source device of Application Example 1, as the temperature increases, the power reduction amount increases, so that the temperature decrease of the light source can be promoted.

  In the light source device of Application Example 1, the related information includes a second portion in which the target power for a temperature equal to or higher than a fourth temperature higher than the first temperature is set to zero.

  According to the light source device of Application Example 1, when the temperature of the light source exceeds a predetermined value, the supply of electric power to the light source can be stopped, so that damage to the light source due to a temperature rise can be suppressed.

  In the light source device of Application Example 1, the acquisition unit includes a temperature sensor installed in the vicinity of the light source.

  Since the temperature in the vicinity of the light source and the temperature of the light source are closely related, according to the light source device of the above aspect, the temperature of the light source can be specified with high accuracy.

  The light source device of Application Example 1 further includes a base plate for mounting the light source, and the temperature sensor measures the temperature of the base plate as the temperature.

  Since the base plate is a part of the light source, according to the light source device of Application Example 1, the temperature sensor can be easily attached. Therefore, the temperature of the light source can be obtained with high accuracy without directly attaching a temperature sensor to the light emitting element itself.

  The light source device of Application Example 1 further includes a light source mounting structure for fixing the light source, and the temperature sensor measures the temperature of the light source mounting structure as the temperature.

  According to the light source device of Application Example 1, the temperature can be acquired without hindering the progress of the emitted light from the light source.

  In the light source device of Application Example 1, the drive circuit supplies the electric power by pulse modulation, and the control unit narrows a width of a pulse generated by the pulse modulation, and reduces an amplitude of the pulse. The power is reduced by controlling the drive circuit to perform any one of the above.

  According to the light source device of Application Example 1, the power to be supplied to the light source can be easily controlled.

  The light source device of Application Example 1 further includes light intensity acquisition means for acquiring the light intensity of the light emitted from the light source, and the control unit performs the control based on the light source temperature and the light intensity.

  According to the light source device of Application Example 1, since the power to be supplied to the light source can be controlled using not only the temperature but also the light intensity, the control accuracy can be improved.

  In the light source device of Application Example 1, the light source device includes a red light source for outputting red light, a green light source for outputting green light, and a blue light source for outputting blue light, and the control unit includes: Based on a reference temperature that is the highest temperature among the light source temperatures of the red light source, the green light source, and the blue light source, supply to the light source having the reference temperature among the red light source, the green light source, and the blue light source The drive circuit is controlled to reduce the power to be supplied and to reduce the power supplied to another light source.

  According to the light source device of Application Example 1, the power supplied to each color light source can be controlled in conjunction with the reference temperature. Therefore, it is possible to prevent the balance of the output light from the light source from being rapidly lost.

  In the light source device of Application Example 1, the control unit controls the drive circuit so that the white balance of the light source device is maintained constant.

  According to the light source device of Application Example 1, the white balance can be kept constant even when the power is changed. Therefore, color reproducibility can be improved.

  In the light source device of Application Example 1, the control unit controls the drive circuit so that the power per unit time supplied to the color light sources is equal to or less than the power at the maximum light amount of the color light sources.

  According to the light source device of Application Example 1, it is possible to supply power equal to or less than the power that is the maximum light amount to the light source. Therefore, since unnecessary power supply can be suppressed, power can be supplied efficiently. Moreover, the rise of light source temperature and the deterioration of a drive circuit and a light source can be suppressed.

  In the light source device of Application Example 1, the control unit controls the drive circuit to change the power of another light source in conjunction with the power of a light source that cannot secure a predetermined light amount among the color light sources. .

  According to the light source device of Application Example 1, since the power of other light sources can be adjusted in conjunction with the power of a light source that cannot secure a predetermined light amount, white balance can be kept constant with a simple configuration.

  In the light source device of Application Example 1, the control unit controls the drive circuit so as to maintain the white balance constant with reference to the light amount of the red light source.

  According to the light source device of Application Example 1, the power of the other color light source can be adjusted according to the amount of light of the red light source. Since the light amount of the red light source changes depending on the temperature change compared to the blue light source and the green light source, according to the light source device of Application Example 1, the white balance can be kept constant with a simple configuration, and color reproduction can be performed. Can be improved.

  According to the application example 1, the temperature rise of the light source that has reached the reference temperature can be suppressed while controlling all the light sources in consideration of the color balance of the three colors of red light, green light, and blue light. Therefore, a desired color balance can be ensured and the shortening of the useful life of the light source can be suppressed.

  The light source device of Application Example 1 further includes notification means for notifying the user that the temperature of the light source represented by the temperature exceeds a predetermined value.

  According to the light source device of Application Example 1, it is possible to notify the user of the light source that the temperature of the light source has exceeded a predetermined location, and the convenience for the user can be improved.

[Application Example 2]
An image display device comprising the light source device of Application Example 1.

  According to the image display device of the application example 2, it is possible to configure an image display device that can maintain the power of light output from the light source without rapidly decreasing.

[Application Example 3]
A monitor device comprising the light source device of Application Example 1.

  According to the monitor device of the application example 3, it is possible to configure a monitor device that can maintain the power of light output from the light source without rapidly decreasing.

[Application Example 4]
The lighting device is a lighting device including the light source device of Application Example 1.

  According to the illuminating device of Application Example 4, it is possible to configure an illuminating device that can maintain the power of light output from the light source without rapidly decreasing.

  In this invention, it can also comprise as an image display apparatus provided with the various light source device mentioned above, a monitor apparatus, and an illuminating device. The various aspects described above can be appropriately combined or a part of them can be omitted.

A. First embodiment:
A1. System overview:
A projector as an image display apparatus in the first embodiment will be described with reference to FIGS. FIG. 1 is an explanatory diagram illustrating the schematic configuration of the projector in the first embodiment. FIG. 2 is a block diagram illustrating the configuration of the light source device according to the first embodiment.

  As shown in FIG. 1, the projector 1000 includes light source devices 10, 20, 30, a uniformizing optical element 50, a light valve 60, a dichroic prism 70, and a projection lens 80.

  The light source devices 10 to 30 are used as light sources for the projector 1000. The light source device 10 outputs red laser light having a wavelength of about 650 nm, the light source device 20 outputs green laser light having a wavelength of about 540 nm, and the light source device 30 outputs blue laser light having a wavelength of about 430 nm. To do. Since the laser light is absorbed by various devices in the light source device, the amount of light output from the semiconductor laser device and the amount of light used for image projection are slightly different. The detailed configuration of the light source devices 10 to 30 will be described in detail later.

  The uniformizing optical element 50 superimposes incident irradiation light to average out luminance unevenness, and reduces the light amount difference between the end portion and the center portion of the screen. By arranging the uniformizing optical element 50, a bright image can be projected on the entire screen. In this embodiment, a diffractive optical element is used as the uniformizing optical element 50.

  The light valve 60 is formed using high temperature polysilicon (HTPS: High Temperature Poly-Silicon), and is an active matrix drive type transmissive liquid crystal panel. The light valve 60 draws an image by controlling incident light.

  The dichroic prism 70 has a configuration in which four triangular prisms are combined to form a rectangular parallelepiped. The dichroic prism 70 combines the red laser light, the green laser light, and the blue laser light that have passed through the light valve 60 to form an image, and project the image. Project to the lens 80.

  The projection lens 80 projects the image projected from the dichroic prism 70 onto the screen 90.

  As described above, the projector 1000 causes the light emitted from the light source devices 10 to 30 to enter the corresponding light valves 60 to form an image, and then synthesizes the light and projects it onto the screen 90. The viewer visually recognizes the image projected on the screen 90.

  With reference to FIG. 2, the functional blocks of the light source device of the first embodiment will be described. Since the light source devices 20 and 30 have the same configuration as the light source device 10 except that the wavelengths of emitted light are different, the description of the light source devices 20 and 30 is omitted.

  As shown in FIG. 2, the light source device 10 includes a housing 102, a semiconductor laser device 100 a as a laser light source, a second harmonic generation element 110, a resonator 120, a temperature sensor 130, and a temperature controller 140. A power supply drive circuit 150a, a temperature control unit 160a, and a control unit 170. The control unit 170 includes a drive signal control unit 171 and a warning notification unit 172.

  The semiconductor laser device 100a of the light source device 10 outputs laser light having a peak wavelength of about 1300 nm, which is twice the peak wavelength of red laser light of about 650 nm. Note that the semiconductor laser device of the light source device 20 outputs laser light having a peak wavelength of about 1080 nm, which is twice the peak wavelength of green laser light, which is about 540 nm, and the semiconductor laser device of the light source device 30 has a peak of blue laser light. Laser light having a peak wavelength of about 860 nm, which is twice the wavelength of about 430 nm, is output.

  The second harmonic generation element 110 is a non-linear optical element that converts incident light into a substantially half wavelength. Light that is output from the semiconductor laser device 100 a and travels toward the resonator 120 passes through the second harmonic generation element 110, and is converted into light having a half wavelength. That is, the infrared laser light output from each semiconductor laser device of the light source devices 10 to 30 is converted into visible light by passing through the second harmonic generation element 110. The wavelength conversion efficiency by the second harmonic generation element 110 has a non-linear characteristic. For example, the higher the intensity of the laser light incident on the second harmonic generation element 110, the higher the conversion efficiency. The conversion efficiency of the second harmonic generation element 110 is about 40 to 50%.

  The resonator 120 includes a pair of mirrors 121 and 122 that reflect a part of incident light. These mirrors 121 and 122 are provided so as to sandwich the light emitting unit 111 therebetween. The resonator 120 is configured such that the distance between the mirrors 121 and 122 of the resonator is an integral multiple of a half wavelength of a predetermined wavelength, and resonates light having a predetermined wavelength between the mirrors of the resonator. Amplify. Specifically, the mirror 121 provided on the light emission side of the light emitting unit 111 reflects a part (about 98 to 99%) of light having a predetermined wavelength out of the incident laser light toward the mirror 122. At the same time, part of the remaining laser light is transmitted. The mirror 122 reflects the light reflected by the mirror 122 provided on the light emission side of the light emitting unit 111 toward the mirror 122. As described above, light having a predetermined wavelength among the light incident on the resonator 120 is repeatedly reflected and amplified by the mirrors 121 and 122. Since the intensity of the amplified laser light is significantly higher than the intensity of light of other wavelengths, it passes through the mirror 121 of the resonator. The laser light W2 amplified and transmitted through the resonator mirror 122 can be regarded as light having a substantially single wavelength. The mirrors 121 and 122 may be formed of a dielectric multilayer film.

  The temperature sensor 130 is attached to the base plate 101a of the semiconductor laser device 100a, and measures the temperature of the base plate as the temperature of the semiconductor laser device 100a as a light source. The temperature sensor 130 may be disposed in any part of the semiconductor laser device 100a. However, if the temperature sensor 130 is installed on the base plate, the temperature sensor 130 prevents the light emitted from the light emitting unit 111 from traveling toward the second harmonic generation element 110. Without increasing the fragility of the interface by inserting a temperature sensor in the interface formed in the semiconductor laser device, for example, the interface between the light emitting unit 111 and the resonator mirror 122, the temperature of the semiconductor laser device 100a is increased. It can be measured.

  The power supply driving circuit 150a includes a correspondence table 510 as related information, and supplies power for causing the semiconductor laser device 100a to emit light. The association table 510 will be described later.

  The temperature controller 140 is disposed so as to cover the side surface of the second harmonic generation element 110 substantially parallel to the traveling direction of the laser light W2, and has a function of adjusting the temperature of the second harmonic generation element 110. The temperature controller 140 is formed by a Peltier element, for example. The second harmonic generation element 110 absorbs the laser beam that reciprocates in the resonator 120 and the temperature rises. As a result, the crystal temperature rises and the phase matching condition may shift. As a result, since the wavelength conversion efficiency of the second harmonic generation element 110 may be lowered, the temperature controller 140 is arranged to suppress the temperature change of the second harmonic generation element 110.

  The temperature control unit 160a controls the operation of the temperature controller 140 to adjust the temperature of the second harmonic generation element 110 to a predetermined temperature.

  The control unit 170 controls the output power of the semiconductor laser device 100a according to the temperature of the semiconductor laser device 100a acquired from the temperature sensor 130. The output power control will be described later. Further, the warning notification unit 172 displays a warning on the screen 90 via the light valve 60 when the temperature of the base plate acquired from the temperature sensor 130 is higher than a predetermined threshold value.

A2. Regarding the relationship between the temperature and output power of a semiconductor laser device:
Before describing the detailed processing of the light source device of the first embodiment, the relationship between the temperature of the semiconductor laser device and the output power will be described with reference to FIG. FIG. 3 is a correlation graph illustrating the relationship between the temperature of the semiconductor laser device and the output power.

  The correlation graph 500 represents the relationship between the elapsed time and the output power of the semiconductor laser device 100a operating at three types of temperatures T1, T2, and T3 (T1> T2> T3). In this embodiment, the output power represents the amount of light. In the correlation graph 500, the vertical axis represents the output power PW of the semiconductor laser device 100a, and the horizontal axis represents the elapsed time t. The relationship between the output power PW of the semiconductor laser device at the temperature T1 and the elapsed time is represented by a solid line, the relationship between the output power PW of the semiconductor laser device at the temperature T2 and the elapsed time is represented by a broken line, and the semiconductor laser at the temperature T3 The relationship between the output power PW of the apparatus and the elapsed time is represented by a one-dot chain line.

  When the semiconductor laser device is continuously used, it cannot emit light due to package breakage, interface peeling between the base plate and the resonator mirror 122, breakage of the semiconductor chip, and the like. The usable period of the semiconductor laser device (in this embodiment, the usable period indicates a period during which a predetermined amount of light can be emitted) has a correlation with the operating temperature. The semiconductor laser device that emits light is damaged at time t1 and the output starts to suddenly drop, the usable period ends, and the output power becomes “0”. Similarly, the semiconductor laser device emitting light at temperature T2 is damaged at time t2 and the output starts to decrease, and the semiconductor laser device emitting light at temperature T3 is damaged at time t3. The output begins to decrease (in the first embodiment, t1 <t2 <t3). That is, the usable period of the semiconductor laser device operating at a higher temperature is shorter.

A3. Output power control processing:
Details of processing of the light source device of the first embodiment will be described with reference to FIGS. FIG. 4 is a flowchart for explaining the output power control process of the light source device in the first embodiment. FIG. 5 is a correspondence table illustrating the correspondence between the temperature and the output power of the semiconductor laser device in the first embodiment. FIG. 6 is an explanatory diagram illustrating pulses generated by the drive circuit in the first embodiment. FIG. 7 is an explanatory diagram illustrating a warning notification screen in the first embodiment. The output power control process is executed by the control unit 170 controlling each functional block.

The control unit 170 acquires the temperature T of the semiconductor laser device 100a from the temperature sensor 130 (step S10). Specifically, the temperature sensor 130 measures the temperature Ts of the base plate of the semiconductor laser device 100a to which the temperature sensor 130 is attached, and the control unit 170 controls the temperature sensor 130 to the temperature sensor 130 at predetermined time intervals. The temperature Ts measured by is acquired. In the present specification, the threshold T _th1 corresponds to the “second threshold” in the claims, and the threshold T _th3 corresponds to the “first threshold”. Each threshold value may be defined in advance, for example, or may be a value that changes appropriately according to various factors such as elapsed time.

The control unit 170 determines whether or not the temperature Ts is included in a range not less than the threshold T _{th1 and not} more than the threshold T _th2 (step S11). If it is included in the range not less than the threshold value T _{th1 and not} more than the threshold value T _th2 (step S11: YES), it is determined that the setting change of the laser output power is unnecessary, and the temperature Ts is repeatedly acquired from the temperature sensor 130. When the control unit 170 is not included in the range not less than the threshold T _{th1 and not} more than the threshold T _th2 (step S11: NO), the control unit 170 determines whether the temperature Ts is less than the threshold T _th1 (step S12). When the temperature Ts is less than the threshold value T _th1 (step S12: YES), the control unit 170 determines that the laser output power is lower than the desired set power, and increases the output power of the semiconductor laser device (step S13). ). The control unit 170 determines whether the output power is a desired power based on the temperature Ts. However, the control unit 170 directly measures the output power and based on both or at least one of the temperature Ts and the output power. It may be determined whether the output power of the device is a desired power.

If the temperature Ts is not less than the threshold T _th1 (step S12: NO), the control unit 170 compares the temperature Ts with the threshold T _th3 (step S14), and if the temperature Ts is lower than the threshold T _th3 , that is, the temperature When Ts is higher than the temperature T _{th2 and} lower than T _th3 (step S14: NO), the output power of the semiconductor laser device 100a is reduced according to the temperature Ts (step S15). Specifically, the drive signal control unit 171 refers to the association table 510 illustrated in FIG. 5 and the power supply drive circuit 150a so that the output power of the semiconductor laser device 100a becomes the output power corresponding to the temperature Ts. The amount of power supplied to the semiconductor laser device 100a is adjusted.

  The association table 510 will be described with reference to FIG. In the association table 510, the vertical axis represents the sensor temperature, and the vertical axis represents the output power of the semiconductor laser device 100a. For example, when the sensor temperature Ts is equal to or lower than the temperature T3 (range P3 shown in FIG. 5), the output power per unit time of the semiconductor laser device 100a is the output power PW3.

  When the sensor temperature Ts is T3 <Ts ≦ T2 (range P2 shown in FIG. 5), as the temperature rises, the output power of the semiconductor laser device 100a is changed from the output power PW3 to the power PW2 at a ratio of Δd1. Reduced to. Note that Δd1 = | (PW2−PW3) / (T2−T3) |.

  When the temperature Ts of the temperature sensor 130 is T2 <Ts ≦ T1 (range P1 shown in FIG. 5), the output power of the semiconductor laser device 100a is a ratio of Δd2 from the output power PW2 as the temperature rises. The output power is reduced to PW1. Note that Δd2 = | (PW1−PW2) / (T1−T2) | and Δd2> Δd1.

  When the temperature Ts of the temperature sensor 130 is Ts> T1 (range P0 shown in FIG. 5), the power supplied to the semiconductor laser device 100a is PW1, and when Ts ≧ T0, the semiconductor laser device. The power supplied to 100a is “0”, that is. No power is supplied to the semiconductor laser device 100a.

  For example, when acquiring the sensor temperature Ts, the drive signal control unit 171 acquires the output power PWs associated with the sensor temperature Ts with reference to the association table 510, as illustrated in FIG. The power supply driving circuit 150a is controlled so that the output power per unit time of the device 100a becomes the output power PWs.

  Here, the power supply to the semiconductor laser device 100 of the power supply driving circuit 150a will be described with reference to FIG. The power supply drive circuit 150a supplies power by applying a pulse voltage to the semiconductor laser device 100a. The power supply driving circuit 150a adjusts the power supplied to the semiconductor laser device 100a by changing the width and amplitude of the pulse, that is, the voltage, by pulse modulation.

  As shown in FIG. 6, the power supply driving circuit 150a supplies a pulse waveform 200 to the semiconductor laser device 100a during normal operation (range P3 shown in FIG. 5). The pulse waveform 200 is generated so as to have a period S, a pulse width D = W1, and an amplitude A = A1. The amplitude A represents the voltage applied to the power supply driving circuit 150a. When the pulse waveform 200 is applied to the semiconductor laser device 100a for one period, the power pw indicated by the oblique lines in FIG. 6 is supplied to the semiconductor laser device 100a.

  For example, as shown in FIG. 5, when the output power is the output power PWs (PWs <PW3) corresponding to the sensor temperature Ts, the drive signal control unit 171 is supplied from the power supply drive circuit 150a to the semiconductor laser device 100a. The power supply driving circuit 150a is controlled so as to reduce the power. The power supply driving circuit 150a generates a pulse waveform 210 in which the pulse width D is narrowed from W1 to W2 (W1> W2) in accordance with the control from the drive signal control unit 171 and supplies the pulse waveform 210 to the semiconductor laser device 100a.

  Returning to FIG. When the control unit 170 finishes adjusting the output power of the semiconductor laser device 100a, the control unit 170 returns to step S10 and repeats the process.

The control unit 170 compares the acquired temperature T with the threshold T _th3 (step S14). If the temperature T is equal to or higher than the threshold T _th3 (step S14: YES), the warning notification unit 172 causes the semiconductor laser device 100a to A warning to stop the output is displayed on the screen 90 through the light valve 60 (step S16). As shown in FIG. 7, a warning notification message 91 is displayed on the screen 90. The display time may be a time sufficient for notification, for example, about 10 seconds to 30 seconds. In this embodiment, temperature T _th1 <temperature T _th2 <temperature T _th3 , temperature T _th2 is temperature T3, and temperature T _th3 is temperature T0.

  After the warning notification display time elapses, the drive signal control unit 171 stops the power supply to the semiconductor laser device 100a and stops the output of the semiconductor laser device 100a (step S17).

  According to the first embodiment described above, the temperature rise of the semiconductor laser device can be suppressed by reducing the output power by suppressing the amount of power supplied to the semiconductor laser device. Accordingly, shortening of the service life of the semiconductor laser device can be suppressed even when the cooler for cooling the semiconductor laser device fails or when used in an unexpected high temperature environment (for example, an environment exceeding 40 ° C.). . Further, according to the first embodiment, since the output power can be increased in accordance with the temperature decrease of the semiconductor laser device, it is possible to suppress an undesired decrease in the output power. According to the first embodiment, since the temperature sensor is attached to the base plate of the semiconductor laser device, the temperature of the semiconductor laser device can be accurately measured.

  As the temperature rises, the output power from the semiconductor laser device decreases, so that the brightness decreases. However, the human eye hardly changes a slight change in brightness (for example, a decrease of about 10%) to the brightness. It is known that it can be judged as a thing. Therefore, according to the first embodiment described above, it is possible to suppress sudden damage and sudden turn-off of the semiconductor laser device, and it is possible to improve the convenience for the user / viewer.

  Further, according to the first embodiment described above, when the sensor temperature exceeds the threshold value, the power supply to the semiconductor laser device can be stopped and the output of the semiconductor laser device can be stopped. Accordingly, it is possible to suppress the shortening of the life of the semiconductor laser device due to the continuous operation at a high temperature. Also, according to the first embodiment described above, when the operation of the semiconductor laser device is stopped, a warning display indicating that the semiconductor laser device has stopped can be displayed on the screen 90, so that the convenience of the user / viewer can be improved.

B. Second embodiment:
In the second embodiment, a temperature sensor is provided on a light source mounting member to which a semiconductor laser device is attached.

B1. Detailed configuration of light source device:
The light source device in the second embodiment will be described with reference to FIG. As shown in FIG. 8, the light source device of the second embodiment includes a light source mounting member 180 and a sensor cover 131 in addition to the functional blocks of the light source device of the first embodiment. Since the configuration of the light source device of the second embodiment has the same configuration and function as those of the first embodiment except for the mounting position of the light source mounting member and the temperature sensor, the description of overlapping portions is omitted.

  The light source mounting member 180 is made of a resin having heat resistance and high thermal conductivity, and is painted black. A semiconductor laser device 100 a and a temperature sensor 130 are attached to the light source mounting member 180. The temperature sensor 130 may be attached to any part of the light source mounting member 180.

  The sensor cover 131 is formed of a heat-resistant resin, and suppresses laser light (referred to as stray light in this specification) that remains inside without being output to the outside of the light source device 10 from hitting the temperature sensor 130. If the sensor receives laser light that is stray light, the temperature of the light source mounting member 180 may not be accurately measured. That is, the accuracy of the measured temperature may decrease, and the accuracy of control of the output power of the semiconductor laser device 100a may decrease. Therefore, by providing the sensor cover 131, the temperature of the light source mounting member 180 can be accurately measured.

B2. Output power control:
In the second embodiment, the temperature sensor 130 measures the temperature of the light source mounting member 180. The drive signal control unit 171 of the control unit 170 acquires the temperature of the light source mounting member 180 from the temperature sensor 130. The drive signal control unit 171 has association information that associates the acquired temperature of the light source mounting member 180 with the output power of the semiconductor laser device 100a corresponding to the temperature. The association information may be, for example, a table in which temperature and output power are associated as in the association table 510 of the first embodiment, or may be a function of temperature with respect to output power. When using a function, it is preferable to use a function that protrudes upward with respect to temperature.

  Since the light source mounting member 180 has a high thermal conductivity, it has a high correlation with the temperature of the semiconductor laser device 100a attached thereto. Therefore, according to the second embodiment described above, since the temperature of the semiconductor laser device can be obtained with high accuracy, the output power of the semiconductor laser device can be controlled with high accuracy, and the temperature rise of the semiconductor laser device can be suppressed. Therefore, the shortening of the life of the semiconductor laser device can be suppressed.

  In addition, according to the second embodiment described above, since the temperature sensor is installed on the light source mount member to which the semiconductor laser device is attached, the temperature sensor is installed on the semiconductor laser device having a dense structure and low impact resistance. However, it can be installed simply and with reduced damage to the semiconductor laser device.

C. Third embodiment:
In the third embodiment, the temperature of the semiconductor laser device is measured, the light intensity of visible light output from the light source device is measured, and the semiconductors of the three light source devices 10, 20, and 30 are measured based on the temperature and the light intensity. The output power of the laser devices 100a, 100b, and 100c is controlled. The configuration of the projector in the third embodiment is almost the same as the configuration of the projector in the first embodiment described in FIG.

C1. Detailed configuration of light source device:
With reference to FIG. 9, functional blocks of the light source device of the third embodiment will be described. In addition, in order to express a figure simply, structures other than the power supply drive circuit and temperature control unit of the light source devices 20 and 30 are abbreviate | omitted.

  As shown in FIG. 9, the light source device 10 includes a semiconductor laser device 100a as a laser light source, a second harmonic generation element 110, a resonator 120, a temperature sensor 130, a temperature controller 140, and a power supply driving circuit. 150a, temperature control unit 160a, and control unit 170 are provided. The control unit 270 includes a drive signal control unit 271, a warning notification unit 172, and a laser power meter 190 as a light intensity measurement unit. In each configuration of the third embodiment, the same reference numerals as those in the first embodiment have the same configuration / function, and thus description thereof is omitted.

  The laser power meter 190 is a device that includes a light receiving unit and converts the energy of laser light incident on the light receiving unit into an electrical signal. The light receiving unit is configured by, for example, a silicon photodiode. The laser power meter 190 may be disposed on the light path between the second harmonic generating element 110 and the opening 201 of the cover of the light source device, or may pass on the path even if not on the path. You may arrange | position in the site | part which can receive the light which has an energy equivalent to the energy of light.

The drive signal control unit 271 of the control unit 270 includes association tables 510, 520, and 530 and a white balance table 540 for each light source device 10-30. The drive signal control unit 271 acquires the temperature of each semiconductor laser device from the temperature sensor of each light source device, and sets the reference temperature and the reference temperature with the lowest temperature as the reference temperature _Tmin and the highest temperature as the reference temperature _Tmax. The output power of the semiconductor laser device is controlled by adjusting the amount of power supplied from the power source driving circuit of the light source device to the light emitting element based on the correspondence table of the light source device.

  Further, the drive signal controller 271 ensures the white balance of the light output from the three light source devices by referring to the white balance table 540 based on the light intensity after adjusting the output power of the light source device having the reference temperature. As described above, the output power of the semiconductor laser device of another light source device is adjusted. White balance means that when white light is emitted by combining red light, green light, and blue light, a desired white color is emitted by adjusting the color development, that is, the color intensity of each color. If the balance of the color intensity of each color is lost, the white balance will be biased, and the red will become a strong white or the blue will become a strong white. An image having a desired color balance with a small amount can be displayed on the screen 90. The white balance table 540 is a table that defines this white balance.

  The control unit 270 controls all of the three light source devices 10-30. The control unit 270 may be configured in any one of the light source devices, or may be configured outside the three light source devices. Further, for example, the control unit 270 may be configured in all the light source devices, and the control unit of the light source device having the highest temperature may control other light source devices.

C2. Output power control processing:
The output power control process of the third embodiment will be described with reference to FIG. 10 and FIG. 10 and 11 are flowcharts for explaining output power control processing in the third embodiment.

  The control unit 270 acquires the temperature T of each semiconductor laser device from the temperature sensor 130 of all light source devices (step S20).

The control unit 270 determines whether the temperature T of each semiconductor laser device is included in the range of the threshold value T _th1 or more and the threshold value T _th2 or less (step S21). If it is included in the range not less than the threshold value T _{th1 and not} more than the threshold value T _th2 (step S21: YES), it is determined that it is not necessary to change the setting of the laser output power, and the temperature T is repeatedly acquired from the temperature sensor 130. When the temperature T is not included in the range not less than the threshold T _{th1 and not} more than the threshold T _th2 (step S21: NO), the control unit 270 has the lowest reference temperature T _min among the temperatures T of the respective semiconductor laser devices. It is determined whether it is less than the threshold value T _th1 (step S22). When the reference temperature T _min is lower than the threshold value T _th1 (step S22: YES), the control unit 270 determines that the output power of the semiconductor laser device at the reference temperature T _min is lower than the desired set power, and the semiconductor laser The output power of the device is increased (step S23).

  The control unit 270 acquires the light intensity of the light emitted from the semiconductor laser device with increased output power and converted into visible light (step S24). Specifically, the control unit 270 acquires the light intensity of visible light from the laser power meter 190.

  The drive signal control unit 271 refers to the white balance table 540 based on the acquired light intensity, and ensures the white balance of the light output from the three light source devices, so that the semiconductor lasers of other light source devices The output power of the device is adjusted (step S25). Specifically, the drive signal control unit 271 performs white balance of three colors of red light output from the light source device 10, green light output from the light source device 20, and blue light output from the light source device 30. The white balance table 540 that defines the ratio of the light intensity of each color is provided so that the output power of each light source device can be controlled with reference to the white balance table 540.

When the reference temperature T _min is not less than the threshold value T _th1 (step S22: NO), the control unit 270 compares the reference temperature T _max with the threshold value T _th3 among the acquired temperatures T of the respective semiconductor laser devices (step S22). S26) If the reference temperature T _max is lower than the threshold T _th3 , that is, if the reference temperature T _max is higher than the temperature T _{th2 and} lower than T _th3 (step S26: NO), the semiconductor laser device of the reference temperature T _max Is reduced (step S27).

  The control unit 270 acquires the light intensity of the light emitted from the semiconductor laser device whose output power has been reduced and converted into visible light. (Step S28).

  The drive signal control unit 271 refers to the white balance table 540 based on the acquired light intensity, and ensures the white balance of the light output from the three light source devices, so that the semiconductor lasers of other light source devices The output power of the apparatus is adjusted (step S29).

When the control unit 170 finishes adjusting the output power of the semiconductor laser device 100a by controlling the power supplied to the semiconductor laser device 100a according to the sensor temperature Ts, the control unit 170 returns to step S20 and repeats the process.

When the reference temperature T _max is equal to or higher than the threshold value T _th3 (step S26: YES), the warning notification unit 172 of the control unit 270 _issues a warning that the operation of all the semiconductor laser devices is stopped via the light valve 60. Display on the screen 90 for a predetermined display time (step S30).

  After the display time has elapsed, the drive signal control unit 271 of the control unit 270 stops the power supply to the semiconductor laser devices of all the light source devices, and stops the output of the semiconductor laser devices (step S31).

  According to the third embodiment described above, in a projector using a plurality of light source devices, the output of the semiconductor laser device of another light source device according to the suppression of the output power based on the temperature rise of the semiconductor laser device of one light source device. Power can be suppressed so that white balance is secured. Therefore, it is possible to suppress the shortening of the lifetime of the semiconductor laser and to project a high-quality image in which white balance is ensured at the time of image projection onto a screen using a plurality of semiconductor laser devices.

D. Fourth embodiment:
D1. General configuration of monitor device:
In the fourth embodiment, a monitor device including a light source device will be described. FIG. 12 is an explanatory diagram illustrating a monitor device 400 according to the fourth embodiment. The monitor device 400 includes a device main body 410 and an optical transmission unit 420. The apparatus main body 410 includes the light source apparatus 10 of the first embodiment described above. As described in the first embodiment, the light source device 10 includes the semiconductor laser device 100a, the second harmonic generation element 110, and the resonator 120. However, in this embodiment, the semiconductor laser device 100a outputs white laser light.

  The light transmission unit 420 includes two light guides 421 and 422 on the light sending side and the light receiving side. Each of the light guides 421 and 422 is a bundle of a large number of optical fibers, and can send laser light to a distant place. The light source device 10 is disposed on the incident side of the light guide 421 on the light transmission side, and the diffusion plate 423 is disposed on the emission side thereof. The laser light output from the light source device 10 is transmitted to the diffusion plate 423 provided at the tip of the light transmission unit 420 through the light guide 421 and is diffused by the diffusion plate 423 to irradiate the subject.

  An imaging lens 424 is also provided at the tip of the light transmission unit 420, and reflected light from the subject can be received by the imaging lens 424. The received reflected light travels through the light guide 422 on the receiving side and is sent to a camera 411 as an imaging means provided in the apparatus main body 410. As a result. An image based on reflected light obtained by irradiating the subject with laser light emitted from the light source device 10 can be captured by the camera 411.

  According to the monitor device 400 configured as described above, the temperature rise of the semiconductor laser device can be suppressed, and the shortening of the lifetime can be suppressed. Since the monitor device 400 is used in a medical field or the like, sudden damage or sudden turn-off of the semiconductor laser device can be suppressed, and user convenience can be improved.

E. Example 5:
In the first to fourth embodiments, the power to be supplied to the light source is reduced, thereby reducing the temperature of the light source device and suppressing the deterioration of the light source device. In the fifth embodiment, a description will be given of a light source device that adjusts the power supplied to the light source device without causing the observer to feel a change in luminance while keeping the white balance constant after the light source device is activated.

E1. Detailed configuration of light source device:
FIG. 13 is a block diagram illustrating the configuration of the light source device in the fifth embodiment. The light source device 11 of the fifth embodiment has the same configuration as the light source device 10 of the first embodiment, except for the processing by the control unit 370.

E2. Output power control processing:
The output power control process in the fifth embodiment will be described with reference to FIGS. FIG. 14 is a flowchart for explaining output power control processing in the fifth embodiment. FIG. 15 is an explanatory diagram illustrating a target output power table in the fifth embodiment. FIG. 16 is a graph showing the temporal correlation between the temperature change of the light source device and the output power in the fifth embodiment. FIG. 17 is a characteristic graph showing characteristics of input power and light quantity of each color light source in the fifth embodiment. FIG. 18 is a graph showing the temperature dependence of the light amount of each color light source in the fifth embodiment.

  When the control unit 370 detects power-on of the light source device 11 (step S100), the control unit 370 acquires the temperature of the semiconductor laser device 100a from the temperature sensor 130, and sets a target output power that is a specified output power corresponding to the acquired temperature. (Step S102). Specifically, the control unit 370 refers to the target output power table 600 in which the temperature and output target power of the semiconductor laser device 100a are set, and inputs the target output power to the semiconductor laser device 100a.

  As shown in FIG. 15, the target output power table 600 includes items of “temperature” and “target output power”, and a red light source, a blue light source, and a green light source according to the temperature of the semiconductor laser device 100a. Each target output power is set. For example, when the temperature acquired by the temperature sensor 130 is “C”, the target output power of the red light source is “cR”, the target output power of the blue light source is “cB”, and the target output power of the green light source is “cG”. It is. In the fifth embodiment, the target output power of the other color laser device is determined based on the temperature acquired from the temperature sensor of the red laser device. In this way, the control unit 370 determines the target output power at startup.

  The control unit 370 calculates a temperature change amount for a predetermined time (step S104), and estimates a temperature in the steady state of the semiconductor laser device 100a (hereinafter referred to as a steady temperature in the fifth embodiment) (step S106).

  The control unit 370 determines whether or not the temperature change amount that has changed during a predetermined time is equal to or greater than a predetermined value (step S108). When the temperature change amount is greater than or equal to a predetermined value (step S108: YES), the control unit 370 maintains a constant white balance that is a balance of the color temperatures of the red light source, the blue light source, and the green light source. The supply voltage to the power supply driving circuit is changed (step S110). If the temperature change amount is not equal to or greater than the predetermined value (step S108: NO), the control unit 370 ends the process.

  In the graph 700 of FIG. 16, the solid line graph represents the temperature change of the semiconductor laser device, and the broken line graph represents the input power. In the graph 700, the temperature Ta represents a steady temperature that is a steady state temperature at which a stable operation is performed at a constant temperature. As shown in FIG. 16, the control unit 370 calculates the temperature rise ΔT1 of the semiconductor laser device during a certain time Δt1, estimates the steady temperature, and uses the estimated steady temperature and the target output power table 600. Then, the target output power at the steady temperature is set, and the supply voltage to the power supply driving circuit 150a is controlled so as to be the target output power. Here, the control unit 370 maintains the white balance so that the luminance change of each light source has a gradient of 2% or less per 1/60 sec, that is, the temperature after the change with respect to the temperature before the change. The supply voltage to the power supply driving circuit 150a is controlled so that the difference is about 2% or less per 1/60 sec. The target output power is suppressed from frequently fluctuating by updating the target output power when the amount of temperature change that has changed during a predetermined time is equal to or greater than a predetermined value.

  In the characteristic graph 800 of FIG. 17, the vertical axis represents the light amount of each color laser device, and the horizontal axis represents the input power. As shown in FIG. 17, the red laser device has the maximum light amount at the input power Wr, the blue laser device has the maximum light amount at the input power Wb, and the green laser device has the maximum light amount at the input power Wg. Even if powers greater than or equal to Wg and Wb are applied, the amount of light of each color laser device does not increase (the input powers Wr, Wg, and Wb are referred to as rollover points for the respective color light source devices). Since each color laser device has such characteristics, the control unit 370 controls each color laser device to be driven at a power equal to or lower than the respective rollover point.

  In the graph 900 of FIG. 18, the vertical axis represents the light amount of the semiconductor laser device, and the horizontal axis represents the temperature of the semiconductor laser device. As shown in FIG. 18, the red laser device has a higher light amount reduction rate with respect to the temperature rise than the blue laser device and the green laser device. That is, the red laser device has the worst temperature dependency. Therefore, in the fifth embodiment, when the white balance is kept constant when the input power changes, the control unit 370 interlocks with the amount of change of the red laser device to input power to the blue laser device and the green laser device. To change.

  According to the light source device of the fifth embodiment described above, the power supplied to the semiconductor laser device can be controlled according to the gradient of 2% or less per 1/60 sec of the luminance of the semiconductor laser device. By setting the luminance change at this gradient, the luminance of the entire image can be changed without causing the observer to feel the luminance change. Therefore, it is possible to control the power supply while providing an image that does not feel strange to the observer.

  Further, according to the light source device of the fifth embodiment, the target output power of another light source device can be adjusted in conjunction with the light source device having poor temperature dependency among the plurality of light source devices. Therefore, the white balance can be efficiently maintained constant with a simple configuration. In the fifth embodiment, the red light source is linked to the other color light source, but the present invention is not limited to this.

  Further, according to the light source device of the fifth embodiment, since the semiconductor laser device can be operated with electric power equal to or lower than the rollover point, electric power can be supplied efficiently, and deterioration of the light source device can be prevented.

  In the fifth embodiment, the target output power can be updated only when the temperature change is more than a certain value within a certain time. Therefore, it is possible to suppress the target output power from fluctuating due to a slight temperature change.

F. Variation:
(1) In the first embodiment described above, the power supply drive circuit 150a modulates the pulse width. For example, the power supply drive circuit 150a generates a pulse waveform with modulated amplitude, that is, voltage, and supplies the pulse waveform to the semiconductor laser device. May be. In the case of such a modification, the power supply driving circuit 150a preferably includes means for changing the amplitude (voltage). The power supply driving circuit 150a may generate a pulse waveform 220 having a reduced amplitude, that is, a voltage value (pulse width A = A2, A1> A2) and supply the pulse waveform 220 to the semiconductor laser device 100a. Even if the pulse width is narrowed or the pulse amplitude is reduced, the amount of power supplied to the semiconductor laser device 100a can be reduced. However, the pulse waveform 210 with the narrowed pulse width has higher peak energy than the pulse waveform 220. preferable.

(2) In the first embodiment described above, the output power of the semiconductor laser device is controlled to be continuously reduced as the temperature of the semiconductor laser device rises. May be reduced discontinuously.

  FIG. 19 is an association table 520 that associates output power and sensor temperature in this modification. In the association table 520, the vertical axis indicates the sensor temperature, and the vertical axis indicates the output power of the semiconductor laser device 100a. As shown in FIG. 19, in the association table 520, the sensor temperatures are in a plurality of ranges P0 (T1 <sensor temperature Ts ≦ T0), P1 (T2 <sensor temperature Ts ≦ T1), P2 (T3 <sensor temperature Ts ≦ T2). ), P3 (T3 ≧ sensor temperature Ts), and when the sensor temperature is included in each range, the semiconductor laser device is controlled to output at a constant output power. For example, as shown in FIG. 19, when the sensor temperature Ts is included in the range P1, the control unit 170 supplies power to the semiconductor laser device so that the semiconductor laser device outputs with the output power PW4.

  According to the above-described modification, the number of types of pulse signals for generating power to be supplied to the semiconductor laser device may be set to a number corresponding to the temperature range, so that the load on the control unit 170 is reduced and the processing speed is improved. be able to. In the present modification, the temperature range is divided into four sections P0 to P3, but may be less than four sections or more than four sections, for example. If it is less than 4 sections, the processing speed can be improved by reducing processing addition, and if it is more than 4 sections, flexible control can be performed.

(3) In the third embodiment described above, after controlling the output power of the semiconductor laser device based on the temperature of the semiconductor laser device, the semiconductor laser device of another light source device is also controlled based on the light intensity. In a projector equipped with both a temperature sensor and a laser power meter, the output power of the semiconductor laser device may be controlled using only one of temperature and light intensity. Further, only the laser power meter may be provided, and the output power of the semiconductor laser device may be controlled based on only the light intensity with reference to the white balance table 540.

(4) In the third embodiment described above, after controlling the output power of the semiconductor laser device based on the temperature of the reference temperature semiconductor laser device which is the highest temperature, the semiconductor laser device of another light source device is controlled based on the light intensity. Although controlled, for example, the output power of the semiconductor laser device of the light source device at the reference temperature may be reduced and the output power of the semiconductor laser device of another light source device may be reduced without referring to the light intensity. In such a case, the semiconductor laser device of another light source device may be controlled based on the reference temperature.

(5) The temperature sensor for measuring the temperature of the semiconductor laser device as the light source may be installed at any part of the light source device. Even if the semiconductor laser device is not in direct contact with the semiconductor laser device, the temperature of the semiconductor laser device can be obtained if the temperature is disposed at a member or position having a correlation with the temperature of the semiconductor laser device.

(6) The temperature sensor may be directly attached to the light emitting element of the semiconductor laser device. In this way, the accurate temperature of the semiconductor laser device can be measured, and the control accuracy can be improved.

(7) In the third embodiment described above, the light intensity converted into the visible light is measured. For example, the light power passing through the laser power meter between the semiconductor laser device 100a and the second harmonic generation element is measured. Installed in a site where the light intensity can be measured, measures the light intensity of light (for example, infrared light) before being converted to visible light by the second harmonic generation element, and uses it for output control of the semiconductor laser device 100a May be. Since the amount of loss of light increases according to the number of intervening optical elements, the output power of the semiconductor laser device 100a can be measured with higher accuracy.

(8) In the first embodiment described above, warning notification is performed when the output of the semiconductor laser device is stopped. However, the warning notification is not limited to being stopped and may be performed anytime. For example, a warning notification may be given at the start of output reduction of the semiconductor laser device or when the output is reduced by a predetermined level or more. The notification method can take various forms such as not only displaying a message on the screen but also blinking the screen or displaying a predetermined mark. Further, the notification method is not limited to the screen display, and a notification sound or sound may be used.

  As mentioned above, although the various Example of this invention was described, this invention is not limited to these Examples, A various structure can be taken in the range which does not deviate from the meaning.

Explanatory drawing which illustrates about schematic structure of the projector in 1st Example. The block diagram illustrated about the composition of the light source device in the 1st example. 6 is a correlation graph illustrating the relationship between the temperature and output power of a semiconductor laser device. The flowchart explaining the output power control process of the light source device in 1st Example. 6 is a correspondence table illustrating the correspondence between the temperature and output power of the semiconductor laser device in the first embodiment. Explanatory drawing which illustrates about the pulse which the drive circuit in a 1st example generates. Explanatory drawing which illustrates the warning alerting | reporting screen in 1st Example. The block diagram illustrated about the structure of the light source device in 2nd Example. The block diagram illustrated about the structure of the light source device in 3rd Example. The flowchart explaining the output power control process in 3rd Example. The flowchart explaining the output power control process in 3rd Example. Explanatory drawing which illustrates the monitor apparatus in 4th Example. The block diagram illustrated about the structure of the light source device in 5th Example. The flowchart explaining the output power control process in 5th Example. Explanatory drawing which illustrates the target output power table in 5th Example. The graph showing the time-dependent correlation of the temperature change of the light source device in 5th Example, and output power. The characteristic graph showing the characteristic of the input power and light quantity of each color light source in 5th Example. The graph showing the temperature dependence of the light quantity of each color light source in 5th Example. The correspondence table of the output power of the semiconductor laser apparatus and sensor temperature in a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 20, 30 ... Light source device 50 ... Uniformation optical element 60 ... Light valve 70 ... Dichroic prism 80 ... Projection lens 90 ... Screen 91 ... Warning alert message 100a ... Semiconductor laser apparatus 101 ... Base plate 110 ... Second harmonic generation element DESCRIPTION OF SYMBOLS 111 ... Light-emitting part 120 ... Resonator 121, 122 ... Mirror 130 ... Temperature sensor 131 ... Sensor cover 140 ... Temperature controller 150 ... Table 150a ... Power supply drive circuit 160a ... Temperature control unit 170 ... Control unit 171 ... Drive signal control part 172 ... Warning notification unit 180 ... Mounting member 180 ... Light source mounting member 190 ... Laser power meter 200, 210, 220 ... Pulse waveform 270 ... Control unit 271 ... Drive signal control unit 400 ... Monitor device 410 ... Device body 411 ... Camera 4 DESCRIPTION OF SYMBOLS 20 ... Light transmission part 421, 422 ... Light guide ... Light guide 423 ... Diffusing plate 424 ... Imaging lens 500 ... Correlation graph 510, 520 ... Correlation table 1000 ... Projector

Claims (21)

A light source device,
A light source that emits laser light;
A drive circuit for supplying power for driving the light source;
Obtaining means for obtaining the temperature of the light source;
A light source device comprising: a controller that controls the drive circuit so as to reduce the power per unit time supplied from the drive circuit to the light source when the acquired light source temperature is higher than a predetermined first threshold value. . The light source device according to claim 1, further comprising:
A storage unit that stores related information that associates the light source temperature with target power that is power to be supplied to the light source;
The said control part is a light source device which controls the said drive circuit using the acquired said light source temperature and the said relevant information. The light source device according to claim 2,
The related information includes a target power table that associates the light source temperature with the target power,
The said control part is a light source device which controls the said drive circuit using the said light source temperature and the said target electric power table. The light source device according to any one of claims 1 to 3,
When the power per unit time supplied from the drive circuit to the light source is reduced, the control unit has a luminance change amount of the light source that is 1/60 of the luminance value of the light source before the power reduction. A light source device that controls the drive circuit to change the power per unit time supplied to the light source so as to change the gradient to 2% or less per second. The light source device according to any one of claims 1 to 4,
The control unit further compares a second threshold value lower than the first threshold value with the acquired light source temperature, and when the acquired light source temperature is lower than the second threshold value, from the drive circuit, A light source device that controls the drive circuit to increase the power per unit time supplied to a light source. The light source device according to claim 5,
When the power per unit time supplied from the drive circuit to the light source is increased, the control unit causes a change in luminance of the light source to be 1/60 of the luminance value of the light source before the increase in power. A light source device that controls the drive circuit to change the power per unit time supplied to the light source so as to change the gradient to 2% or less per second. The light source device according to claim 2, further comprising:
The control unit is a light source device that controls the drive circuit so that power per unit time supplied to the light source becomes the target power when the drive circuit is activated. The light source device according to claim 4 or 6,
The control unit predicts a steady temperature at which the temperature of the light source is in a steady state using an amount of change of the temperature of the light source in a predetermined time, and determines the power per unit time supplied to the light source to the predicted steady state. A light source device that controls the drive circuit such that the luminance changes with the gradient with respect to a target power defined by a temperature and the target power table. The light source device according to any one of claims 1 to 8,
The said control part is a light source device which controls the said drive circuit according to the light source temperature after the said change, when the said light source temperature changes more than the variation | change_quantity prescribed | regulated previously in a fixed time. The light source device according to claim 2,
The related information includes the target power at a first temperature as a first target power, the target power at a second temperature lower than the first temperature as a second target power, and from the second temperature. When the target power at the low third temperature is the third target power, the difference between the first temperature and the second temperature with respect to the difference between the first target power and the second target power The light source device includes a first portion in which a ratio is larger than a ratio of a difference between the second temperature and the third temperature with respect to a difference between the second target power and the third target power. The light source device according to claim 10,
The related information includes a second part in which the target power for a temperature equal to or higher than a fourth temperature higher than the first temperature is set to 0. The light source device according to claim 1,
The drive circuit supplies the power by pulse modulation,
The control unit reduces the power by controlling the drive circuit to perform either one of narrowing a width of a pulse generated by the pulse modulation and reducing an amplitude of the pulse. Let the light source device. The light source device according to claim 1, further comprising:
A light intensity acquisition means for acquiring the light intensity of the emitted light from the light source;
The control unit is a light source device that performs the control based on the light source temperature and the light intensity. The light source device according to claim 1,
The light source device includes, as the light source, a red light source for outputting red light, a green light source for outputting green light, and a blue light source for outputting blue light,
The control unit is based on a reference temperature that is a highest temperature among the light source temperatures of the red light source, the green light source, and the blue light source, and the reference temperature among the red light source, the green light source, and the blue light source. A light source device that controls the drive circuit so as to reduce the power supplied to a light source having a light source and to reduce the power supplied to another light source. The light source device according to claim 14,
The light source device, wherein the control unit controls the drive circuit so that a white balance of light output from each color light source is maintained constant. The light source device according to claim 14 or 15,
The control unit is a light source device that controls the drive circuit such that power per unit time supplied to the color light sources is equal to or less than power at the maximum light amount of the color light sources. The light source device according to claim 16,
The said control part is a light source device which controls the said drive circuit so that the electric power of the other light source may be changed in response to the electric power of the light source which cannot ensure the light quantity prescribed | regulated previously among each color light source. The light source device according to claim 17,
The control unit is a light source device that controls the drive circuit so as to maintain the white balance constant with reference to a light amount of the red light source.   An image display device comprising the light source device according to claim 1.   A monitor device comprising the light source device according to claim 1.   An illumination device comprising the light source device according to any one of claims 1 to 18.

Images