JP2019158642A - Light source device, projector and correction method of optical sensor - Google Patents

Abstract

To provide a light source device capable of reducing an influence of a secular change in a spectral characteristic of an optical sensor.SOLUTION: A light source device includes: a light source section 2 which emits mixed color light including color components of RGB; an optical sensor 3 which detects a light quantity for each color component of the light emitted by light source section 2; a storage section 4 which previously stores first characteristic data indicating a change of a value detected by the optical sensor 3 for a change of a current amount supplied to the light source section 2 for at least one color component; and a control section 1 which controls a color temperature of the light emitted by the light source section 2 on the basis of the value detected by the optical sensor 3 for each color component. The control section 1 gradually changes the current amount supplied to the light source section 2, acquires second characteristic data indicating the change of the value detected by the optical sensor 3 for the gradual change of the current amount for at least one color component, and corrects the value detected by the optical sensor 3 on the basis of a difference between the second characteristic data and the first characteristic data.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light source device, a projector, and an optical sensor correction method.

A projector is known that projects light (white) emitted from a light source device into a red component (R), a green component (G), and a blue component (B), and projects an image obtained by modulating the light of each color component. In this projector, it is desirable to keep the color temperature of the light emitted from the light source device constant.
Light source devices that emit white light include those using a lamp light source and those using a plurality of solid light sources having different colors. The solid light source is, for example, a laser light source such as a laser diode (LD), a light emitting diode (LED), or a phosphor.
In the light source device using the lamp light source, the color temperature of the emitted light (white) cannot be adjusted. On the other hand, in a light source device using a plurality of solid light sources having different colors, the color temperature of emitted light can be adjusted by controlling the amount of current of each solid light source.

  In general, in a light source device capable of adjusting a color temperature, an optical sensor including a color filter that separates incident light into RGB color components is used. The optical sensor receives a part of the light emitted from the light source device and detects the light amount of each of the RGB color components. The control unit controls the amount of current supplied to each solid-state light source so that the color temperature of the light emitted from the light source device becomes a predetermined value based on the detection values of the RGB color components.

  Patent Document 1 describes a projector that adjusts color temperature using a plurality of optical sensors. In this projector, in order to solve the variation in the output value of each photosensor due to individual differences, the output value of each photosensor is corrected using light of a specific color component of RGB.

Japanese Unexamined Patent Publication No. 2016-45175

However, the light source device that adjusts the color temperature using the above-described optical sensor has the following problems.
When light from a light source such as a laser light source is detected by a photosensor for a long period of time, the spectral characteristics of the photosensor (spectral transmission characteristics of the color filter) change.

For example, the irradiation with blue light or red light causes secular changes in the rising and falling portions of the pass / cut of the green spectral characteristic. Similar aging occurs with respect to blue spectral characteristics and red spectral characteristics. In particular, since laser light has a very narrow spectrum width and high energy density, when a laser light source is used, a secular change in spectral characteristics appears remarkably.
When the spectral characteristics of the optical sensor change, it is impossible to accurately detect the light amounts of the RGB color components. As a result, it becomes difficult to adjust the color temperature of the light emitted from the light source device to the target value.

  Note that the above problem can be solved by replacing a photosensor whose spectral characteristics have changed with a new photosensor. However, the light sensor is usually housed in the light source unit, and in order to replace the light sensor, the user is forced to perform a very troublesome work such as taking out the light source unit and removing the light source. Thus, the replacement work of the optical sensor is very troublesome for the user.

  In the projector described in Patent Document 1, the variation in the output value of each optical sensor due to individual differences can be solved, but the secular change of the spectral characteristics of the optical sensor is not taken into consideration. For this reason, when the spectral characteristics of the optical sensor change, the same problem as described above occurs.

  An object of the present invention is to provide a light source device, a projector, and a correction method for an optical sensor, which can solve the above problems and can reduce the influence of secular change in spectral characteristics of the optical sensor.

  In order to achieve the above object, the first light source device of the present invention receives supply of current, emits mixed color light including a red component, a green component, and a blue component, and emits light of each color component according to the amount of supplied current. A light source unit that varies in proportion, a light sensor that separates a part of light emitted from the light source unit into the red component, the green component, and the blue component, and detects a light amount of each color component; the red component, the green component, and For at least one color component of the blue component, a storage unit preliminarily storing first characteristic data indicating a change in detection value of the photosensor with respect to a change in the amount of current supplied to the light source unit, and the photosensor detects And a control unit that controls the amount of current supplied to the light source unit so that the color temperature of the light emitted from the light source unit becomes a predetermined value based on the detected value of each color component. The control unit changes the amount of current supplied to the light source unit step by step at an arbitrary timing to obtain a detection value of the photosensor for each step for the at least one color component, Second characteristic data indicating a change in the detection value of the photosensor with respect to a change in the current amount is obtained, and the photosensor is based on a difference between the second characteristic data and the first characteristic data. The detected value of the detected at least one color component is corrected.

  The first projector of the present invention projects the light source device, an image forming unit that forms an image by modulating light emitted from the light source device based on an input video signal, and an image formed by the image forming unit. A projection optical system.

  According to the first photosensor correction method of the present invention, when a current is supplied, mixed color light including a red component, a green component, and a blue component is emitted, and a light amount and a ratio of each color component change in accordance with a supply current amount. A light sensor correction method for separating the light emitted from the light source unit into the red component, the green component, and the blue component, and detecting the light amount of each color component, wherein at least one of the red component, the green component, and the blue component For the color component, first characteristic data indicating a change in the detection value of the photosensor with respect to a change in the amount of current supplied to the light source unit is stored in advance, and the amount of current supplied to the light source unit at an arbitrary timing The detection value of the photosensor for each step is obtained for each of the at least one color component, and the change in the detection value of the photosensor with respect to the change in the stepwise current amount is indicated. Acquiring second characteristic data, and correcting a detection value of the at least one color component detected by the photosensor based on a difference between the second characteristic data and the first characteristic data. .

  According to the present invention, it is possible to reduce the influence of secular change of the spectral characteristics of the optical sensor without replacement of parts.

It is a block diagram which shows the structure of the light source device by the 1st Embodiment of this invention. It is a block diagram which shows the structure of the projector provided with the light source device by the 2nd Embodiment of this invention. It is a spectral characteristic figure of blue laser light. It is a spectral characteristic diagram for demonstrating the time-dependent change of the spectral characteristic of an optical sensor. It is a flowchart which shows the preparation procedure of the characteristic data of an initial stage. It is a flowchart which shows the preparation procedure of the characteristic data at the time of producing a time-dependent change in the spectral characteristic of an optical sensor, and current value versus difference data. It is a flowchart which shows the specific process sequence of table correction calculation. FIG. 6 is a diagram showing an example of characteristic data created by the procedure shown in FIG. 5. It is a figure which shows an example of the characteristic data produced in the procedure shown in FIG. It is a flowchart which shows one procedure of a color temperature control process.

Next, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing a configuration of a light source device according to the first embodiment of the present invention.
Referring to FIG. 1, the light source device includes a control unit 1, a light source unit 2, an optical sensor 3, and a storage unit 4. The light source unit 2 is supplied with current and emits mixed color light including a red component (R), a green component (G), and a blue component (B), and the amount of light and the ratio of each color component are in accordance with the amount of supplied current. It is configured to change. Light emitted from the light source unit 2 is light emitted from the light source device.

The optical sensor 3 receives part of the light emitted from the light source unit 2, separates the received light into a red component, a green component, and a blue component, and detects the light amount of each color component. The optical sensor 3 transmits a detection signal indicating the result of detecting the light amount of each color component to the control unit 1.
The storage unit 4 previously stores first characteristic data indicating a change in the detection value of the optical sensor 3 with respect to a change in the amount of current supplied to the light source unit 2 for at least one color component of the red component, the green component, and the blue component. Storing.

  The control unit 1 controls the amount of current supplied to the light source unit 2 so that the color temperature of the emitted light from the light source unit 2 becomes a predetermined value based on the detection value of each color component detected by the optical sensor 3. Further, the control unit 1 changes the amount of current supplied to the light source unit 2 stepwise at an arbitrary timing, and acquires the detection value of the photosensor 3 for each step for the at least one color component. The second characteristic data indicating the change in the detection value of the optical sensor 3 with respect to the stepwise change in the current amount is acquired. Then, the control unit 1 corrects the detection value of the at least one color component detected by the optical sensor 3 based on the difference between the second characteristic data and the first characteristic data.

According to the light source device of the present embodiment, the following operational effects are obtained.
An error occurs in the detection value of the optical sensor 3 with the aging of the spectral characteristics. The difference between the first characteristic data and the second characteristic data corresponds to an error in the detection value of the optical sensor 3 that occurs with the aging of the spectral characteristics. In the light source device of the present embodiment, the detection value of the optical sensor 3 is corrected based on the difference between the first characteristic data and the second characteristic data. As a result, it is possible to remove errors that have occurred with the aging of the spectral characteristics. Therefore, the influence of the secular change of the spectral characteristics of the optical sensor 3 can be reduced without replacement of parts.

In the light source device of the present embodiment, the at least one color component may be a green component.
In the light source device of the present embodiment, the storage unit 4 stores first characteristic data indicating a change in the detection value of the optical sensor 3 with respect to a change in the amount of current supplied to the light source unit 2 for each color component. May be. In this case, the control unit 1 acquires the second characteristic data for each color component, and based on the difference between the second characteristic data and the first characteristic data, each control unit 1 detects each color component detected by the optical sensor 3. The detection value may be corrected.
In addition, after the correction of the detection value of the color component is performed, the control unit 1 may calculate the color temperature of the light emitted from the light source unit 2 based on the detection value of the color component detected by the optical sensor 3.

In the light source device of the present embodiment, the light source unit 2 includes a laser light source that emits blue laser light, a part of the blue laser light is converted into fluorescence including a red component and a green component, and the fluorescence and the blue laser And a phosphor portion that emits mixed color light including the remainder of the light. In this case, the control unit 1 determines the amount of current supplied to the blue laser light source based on the detection value of each color component detected by the optical sensor 3 so that the color temperature of the light emitted from the light source unit 2 becomes a predetermined value. You may control.
In the above case, it may further include a brightness sensor that receives a part of the light emitted from the light source unit 2 and detects the brightness of the laser light source. In this case, the control unit 1 detects the brightness sensor when the second characteristic data is acquired with respect to the brightness detection value of the laser light source detected by the brightness sensor when the first characteristic data is acquired. The second characteristic data may be corrected based on the ratio of the detected values of the brightness of the laser light source.

  In addition, the light source device of the present embodiment, an image forming unit that forms an image by modulating light emitted from the light source device based on an input video signal, a projection optical system that projects an image formed by the image forming unit, A projector may be provided.

(Second Embodiment)
FIG. 2 is a block diagram showing a configuration of a projector including the light source device according to the second embodiment of the present invention.

  Referring to FIG. 2, the projector includes a control unit 10, a power supply unit 11, a light source control unit 12, a light source unit 13, an optical engine 14, a projection lens 15, a UI (User Interface) unit 16, a video input unit 17, and an image conversion unit. 18, a video output unit 19, a light sensor 20, a storage unit 21, and a brightness sensor 22. A portion including the control unit 10, the power source unit 11, the light source control unit 12, the light source unit 13, the UI unit 16, the optical sensor 20 storage unit 21, and the brightness sensor 22 can be referred to as a light source device. Here, the control part 10 and the light source control part 12 may be comprised by one control part which consists of CPU (Central Processing Unit).

  The power supply unit 11 supplies power to each unit of the projector. The light source unit 13 includes a plurality of laser light sources 13a and an optical unit 13b that converts the laser light from the laser light sources 13a into white light and emits the light. The light emitted from the optical unit 13b (white light) is the light emitted from the light source unit 13. Each laser light source 13 a is supplied with electric power (current) from the power supply unit 11 via the light source control unit 12. The light source unit 13 is an example of a light source unit that receives supply of current, emits mixed color light including a red component, a green component, and a blue component, and changes the light amount and the ratio of each color component according to the amount of supplied current.

  The optical engine 14 includes a display unit 14 a that forms an image based on the video signal supplied from the video output unit 19. The display unit 14a includes a display panel that separates the light emitted from the light source unit 13 (white light) into a plurality of color lights and modulates each color light spatially / temporally to form an image. As the display panel, a DMD (digital mirror device), a liquid crystal display panel, or the like can be used. The projection lens 15 enlarges and projects the image formed on the display unit 14a on the projection surface.

  The optical sensor 20 is disposed so as to receive a part of the light emitted from the light source unit 13 (white light). The light received by the optical sensor 20 is not effective light that travels toward the optical engine 14 but is ineffective light that does not contribute to image formation. The optical sensor 20 separates the received light into a red component, a green component, and a blue component, and detects the light amount of each color component. The optical sensor 20 transmits a detection signal indicating the result of detecting the light amount of each color component to the control unit 10. For example, the optical sensor 20 integrates the data of each color component of RGB over a predetermined capturing time, and outputs the result as a sensor data value.

  The brightness sensor 22 is disposed so as to receive a part of the light emitted from the light source unit 13 (white light). The brightness sensor 22 transmits a detection signal indicating the brightness of the light source unit 13 (or a detection signal indicating the amount of incident light from the light source unit 13) to the control unit 10. The brightness of the light source unit 13 corresponds to a current value set in the light source unit 13. For example, the brightness sensor 22 integrates brightness data over a predetermined capture time and outputs the result as a sensor data value. The brightness sensor is also called an illuminance sensor. The brightness sensor 22 may be built in the optical sensor 20.

The video input unit 17 receives a video signal from an external video output device. The video input unit 17 supplies the video signal received from the external video output device to the image conversion unit 18. The external video output device is, for example, a personal computer or a DVD (Digital Versatile Disc) player. The video signal is a digital video signal or an analog video signal.
The image conversion unit 18 performs image conversion processing (for example, resolution conversion processing, image compression processing, etc.) necessary for image formation on the display unit 14 a on the video signal supplied from the video input unit 17. The image conversion unit 18 supplies the video signal after the image conversion process to the video output unit 19. The video output unit 19 outputs the video signal from the image conversion unit 18 to the display unit 14a.

The UI unit 16 receives user input and supplies an operation signal corresponding to the input to the control unit 10. The user can input information necessary for operating the projector using the UI unit 16 (for example, information necessary for color temperature adjustment). In addition, the user can perform an off / on operation of the power source using the UI unit 16.
The light source control unit 12 controls the lighting operation of each laser light source 13 b of the light source unit 13 in accordance with a control signal from the control unit 10. For example, the light source control unit 12 controls the amount of current supplied to each laser light source 13b in accordance with a control signal from the control unit 10.

  The storage unit 21 stores programs and data necessary for operating the projector. Moreover, the memory | storage part 21 can store the characteristic data 21a and 21b and the electric current value versus difference data 21c, for example. The characteristic data 21a is data acquired at the time of factory shipment. The characteristic data 21b is data acquired at an arbitrary timing. Each of the characteristic data 21a and 21b includes table data indicating a change in the detection value of the optical sensor 20 with respect to a change in the amount of current supplied to the laser light source 13b. This table data can be created by stepwise changing the amount of current supplied to the laser light source 13b and acquiring the detection values of the optical sensor 20 for each color component for each color component. The current value pair difference data 21c is created based on the characteristic data 21a and 21b.

  The control unit 10 includes a CPU and the like, and controls the operation of each unit of the projector according to an operation signal from the UI unit 16. For example, the control unit 10 generates the light source unit 13 based on the process of creating the characteristic data 21a and 21b and the current value versus difference data 21c, the process of correcting the detection value of the optical sensor 20, and the detection signal of the optical sensor 20. A process for adjusting the color temperature of the emitted light to a predetermined value is performed.

Next, the operation of the projector of this embodiment will be described in detail.
First, the temporal change in spectral characteristics of the optical sensor 20 and the influence thereof will be described. Here, it is assumed that the light source unit 13 emits mixed color light including blue laser light.

FIG. 3 is a spectral characteristic diagram of blue laser light. In this example of spectral characteristics, the wavelength in the vicinity of about 450 nm which is the blue wavelength region is prominently high, and the light intensity is concentrated.
FIG. 4 is a spectral characteristic diagram for explaining the temporal change of the spectral characteristics of the optical sensor 20. In FIG. 4, a graph indicated by a broken line is a waveform indicating the spectral characteristics of the photosensor in the initial stage. A graph indicated by a solid line is a waveform showing the spectral characteristics of the optical sensor 20 that has changed over time with long-term use. The initial stage indicates, for example, the time of factory shipment.

When the optical sensor 20 receives blue laser light with a very narrow spectral width and high energy density as shown in FIG. 3 over a long period of time, the spectral characteristics of the optical sensor 20 change over time as shown in FIG. Produce.
In the example of FIG. 4, the rising part of the pass / cut of the green spectral characteristic shifts to the short wavelength side (change over time indicated by “A” in FIG. 4), and the falling part of the pass / cut shifts to the long wavelength side. is doing. As for the blue spectral characteristic and the red spectral characteristic, the rising part of the pass / cut shifts to the short wavelength side, and the falling part of the pass / cut shifts to the long wavelength side. However, the shift amount of the blue spectral characteristic and the red spectral characteristic is smaller than the shift amount of the green spectral characteristic.

  When the light emitted from the light source unit 13 is detected using the optical sensor 20 that has changed with time as shown in FIG. 4, an error occurs in the detection values of the RGB color components of the optical sensor 20. For example, due to the time-dependent change of the green spectral characteristic “A”, part of the blue component light is detected as a green component, and the green component light cannot be detected accurately. For example, even if the light source unit 13 emits only blue light, the light sensor 20 detects the emitted light of the light source unit 13 as blue component light and green component light.

  In the projector according to the present embodiment, the control unit 10 creates the characteristic data 21a and 21b and the current value vs. difference data 21c in order to correct the output value of the optical sensor 20 that has changed with time in the spectral characteristics.

  Hereinafter, the process of creating the characteristic data 21a, 21b and the current value versus difference data 21c will be described in detail.

First, the process of creating the characteristic data 21a will be described.
FIG. 5 is a flowchart showing a procedure for creating the initial stage characteristic data 21a.
Referring to FIG. 5, first, the control unit 10 sets a first-stage current value for the light source control unit 12 in accordance with an initial-stage activation instruction from the UI unit 16 (step S10). Here, the predetermined current setting range is divided into a plurality of stages, for example, every 5% of the maximum current value. The control unit 10 sets a minimum current value within a predetermined current setting range as the first stage current value. Note that the current setting range and the current value at each stage can be arbitrarily set by the user using the UI unit 16.

Next, the light source controller 12 operates the laser light source 13a with the current value set in step S10 (step S11).
Next, the optical sensor 20 receives part of the light emitted from the light source unit 13 and transmits a detection signal indicating the detection value of each color component of RGB to the control unit 10. And the control part 10 acquires the optical sensor data value of each color component of RGB based on the detection signal from the optical sensor 20 (step S12).

  Next, the brightness sensor 22 receives a part of the light emitted from the light source unit 13 and transmits a detection signal indicating brightness to the control unit 10. And the control part 10 acquires a brightness sensor data value based on the detection signal from the brightness sensor 22 (step S13). This step S13 may be performed before step S12.

Next, the control unit 10 determines whether or not the current current set value is the maximum current value (step S14).
When the determination result of step S14 is “No”, the control unit 10 sets the current value of the next stage for the light source control unit 12 (step S15). After step S15, step S11 is executed.

When the determination result of step S14 is “Yes”, the control unit 10 creates a table of current values versus sensor values from the minimum current value to the maximum current value (step S16).
Finally, the control unit 10 stores the table created in step S16 in the storage unit 21 as a reference table (step S17). This reference table is the characteristic data 21a.
Next, the creation process of the characteristic data 21b and the current value versus difference data 21c will be described.

FIG. 6 is a flowchart showing a procedure for creating the characteristic data 21b and the current value versus difference data 21c.
Referring to FIG. 6, first, the control unit 10 sets a first-stage current value for the light source control unit 12 in accordance with the second and subsequent activation instructions from the UI unit 16 (step S20). The setting of the current setting range and the stage is the same as the process of creating the characteristic data 21a, and the control unit 10 sets the minimum current value as the current value of the first stage. Note that the second and subsequent activation instructions are activation instructions performed after the initial stage.

Next, the light source controller 12 operates the laser light source 13a with the current value set in step S20 (step S21).
Next, the optical sensor 20 receives part of the light emitted from the light source unit 13 and transmits a detection signal indicating the detection value of each color component of RGB to the control unit 10. And the control part 10 acquires the optical sensor data value of each color component of RGB based on the detection signal from the optical sensor 20 (step S22).

Next, the brightness sensor 22 receives a part of the light emitted from the light source unit 13 and transmits a detection signal indicating brightness to the control unit 10. And the control part 10 acquires a brightness sensor data value based on the detection signal from the brightness sensor 22 (step S23). This step S23 may be performed before step S22.
Next, the control unit 10 determines whether or not the current current set value is the maximum current value (step S24).

When the determination result of step S24 is “No”, the control unit 10 sets the current value of the next stage to the light source control unit 12 (step S25). After step S25, step S21 is executed.
When the determination result of step S24 is “Yes”, the control unit 10 creates a table of current values versus sensor values from the minimum current value to the maximum current value (step S26). This table of current values versus sensor values is characteristic data 21b.

  Finally, the control unit 10 performs table correction calculation based on the table created in step S26 and the reference table stored in the storage unit 21 in step S17 of FIG. S27).

FIG. 7 is a flowchart showing a specific processing procedure of the table correction calculation in step S27.
Referring to FIG. 7, first, the control unit 10 reads the reference table from the storage unit 21 (step S30).

  Next, the brightness sensor 22 measures the brightness at the currently set current value, and transmits the detected value (current brightness sensor data value) to the control unit 10. And the control part 10 calculates the ratio (brightness ratio) of the present brightness sensor data value with respect to the brightness sensor data value acquired at the time of preparation of a reference | standard table (step S31).

  Next, the control unit 10 divides the current value vs. sensor value (table value) created in step S26 of FIG. 6 by the brightness ratio obtained in step S31, so that the reference table is created (initial stage table). The current value in the state of the light source unit 13 at the time of creation) is developed to the sensor value (table value). By dividing the current value versus the sensor value by the brightness ratio, it is possible to remove the influence of the light amount decrease due to the aging of the light source unit 13. Then, the control unit 10 creates a difference data table by subtracting the reference table value from the developed current value versus sensor value (table value) (steps S32 and S33). This difference data table is current value vs. difference data 21c.

  6 and 7 described above may be performed at an arbitrary timing or periodically.

  FIG. 8 shows an example of the characteristic data 21a based on the reference table. This characteristic data 21a is a graph of the current value vs. sensor value table created in step S16 of FIG. FIG. 8 shows changes in sensor values with respect to changes in current values for RGB color components, and changes in sensor values with respect to changes in current values for brightness.

  FIG. 9 shows an example of the characteristic data 21b. The characteristic data 21b is obtained when the spectral characteristics of the optical sensor 20 change with time, and is a graph of the current value versus sensor value table created in step S26 of FIG. FIG. 9 shows changes in sensor values with respect to changes in current values for RGB color components, and changes in sensor values with respect to changes in current values for brightness. Compared with the characteristic data 21a at the initial stage shown in FIG. 8, the graph of the green sensor value is greatly shifted in the direction of increasing the sensor value.

  By subtracting the sensor data value of the characteristic data 21a shown in FIG. 8 from the value obtained by dividing the sensor data value of the characteristic data 21b shown in FIG. 9 by the brightness ratio, the current value versus difference data 21c can be created. .

Next, a process for controlling the color temperature by correcting the output value of the optical sensor 20 that has caused a change in spectral characteristics with time using the current value versus difference data 21c will be described.
FIG. 10 is a flowchart showing a procedure of the color temperature control process.
Referring to FIG. 10, first, the control unit 10 sets the current value received via the UI unit 16 to the light source control unit 12. Then, the light source control unit 12 operates the laser light source 13a with the set current value (step S40).

Next, the optical sensor 20 receives part of the light emitted from the light source unit 13 and transmits a detection signal indicating the detection value of each color component of RGB to the control unit 10. And the control part 10 acquires the optical sensor data value of each color component of RGB based on the detection signal from the optical sensor 20 (step S41).
Next, the control unit 10 corrects the optical sensor data values of the RGB color components acquired in step S41 based on the current value pair difference data 21c (step S42). Specifically, the optical sensor data value is corrected by subtracting the difference data from the optical sensor data value. The optical sensor data values of the respective RGB color components after correction are R / G / B values used for calculating the color coordinates (x, y).

Next, the control unit 10 passes the value of R / G / B acquired in step S42 through a matrix conversion equation to the color coordinates (x, y), so that the current color temperature of the light emitted from the light source unit 13 is obtained. The value of the indicated color coordinate (x, y) is calculated. Since the calculation using the matrix conversion formula to the color coordinates (x, y) is a well-known method, a detailed description thereof is omitted here.
Next, the control unit 10 determines whether or not the current color coordinate (x, y) value acquired in step S44 matches the target color coordinate value (step S45).

When the determination result of step S45 is “No”, the control unit 10 emits the light source unit 13 based on the difference (deviation amount) between the current color coordinate (x, y) value and the target color coordinate value. A current value for obtaining the color temperature of the light close to the target color coordinate value is obtained. And the control part 10 sets the calculated | required electric current value with respect to the light source control part 12, and the light source control part 12 operates the laser light source 13a with the set electric current value (step S46). After step S46, step 41 is executed.
Note that the above description of the operation is an operation description when the blue laser light is used, but the same operation is performed even when laser light of other colors such as red laser light is used.

According to the projector of the present embodiment described above, it is possible to reduce the influence of secular change of the spectral characteristics of the optical sensor 20 without replacement of parts.
Further, even if the optical sensor 20 having a secular change in spectral characteristics is used, the correct color coordinates can be obtained, so that the target color coordinates can be surely adjusted.

The following modifications can be applied to the projector according to the present embodiment.
Since the light amount of the light source unit 13 decreases due to deterioration over time, the current value vs. difference data 21c is created in consideration of the influence of this light amount decrease. However, when it is not necessary to consider the aging of the light source unit 13, the brightness sensor 22 may be removed. In this case, step S13 is deleted in the procedure of FIG. 5, step S23 is deleted in the procedure of FIG. 6, step S31 is deleted in the procedure of FIG. The operation can be explained by changing to “reference table value”.
Further, as shown in FIG. 4, since the change with time of the green spectral characteristic is the largest, the output value of the optical sensor 20 may be corrected only for the green component.

In addition, the light source unit 13 is configured to receive current supply, emit mixed color light including a red component, a green component, and a blue component, and change the light amount and the ratio of each color component according to the supply current amount. Any configuration may be applied.
For example, the light source unit 13 may have a configuration in which a laser light source that is an excitation light source and a phosphor are combined. In this case, the light source unit 13 converts a laser light source that emits blue laser light, a part of the blue laser light into fluorescence that includes a red component and a green component, and color mixing that includes the fluorescence and the remainder of the blue laser light. And a phosphor portion that emits light.
In addition, the light source unit 13 may include a laser light source, an LED, or a combination of these light sources as a light source for each color of RGB.

DESCRIPTION OF SYMBOLS 1 Control part 2 Light source part 3 Optical sensor 4 Memory | storage part

Claims (8)

A light source unit that receives a current supply, emits mixed color light including a red component, a green component, and a blue component, and the amount of light and the ratio of each color component change according to the amount of supply current;
A part of the light emitted from the light source unit is separated into the red component, the green component and the blue component, and an optical sensor for detecting the light amount of each color component;
A storage unit that stores in advance first characteristic data indicating a change in detection value of the photosensor with respect to a change in the amount of current supplied to the light source unit for at least one color component of the red component, the green component, and the blue component When,
A control unit that controls an amount of current supplied to the light source unit based on a detection value of each color component detected by the photosensor so that a color temperature of light emitted from the light source unit becomes a predetermined value; Have
The control unit changes the amount of current supplied to the light source unit step by step at an arbitrary timing to obtain a detection value of the photosensor for each step for the at least one color component, Second characteristic data indicating a change in the detection value of the photosensor with respect to a change in the current amount is obtained, and the photosensor is based on a difference between the second characteristic data and the first characteristic data. A light source device that corrects a detected value of the detected at least one color component.   The light source device according to claim 1, wherein the at least one color component is the green color component. The storage unit stores, for each color component, the first characteristic data indicating a change in the detection value of the photosensor with respect to a change in the amount of current supplied to the light source unit,
The control unit obtains the second characteristic data for each color component, and the color components detected by the photosensor based on a difference between the second characteristic data and the first characteristic data. The light source device according to claim 1, wherein the detected value is corrected.   The correction unit calculates the color temperature of the light emitted from the light source unit based on the detection value of each color component detected by the optical sensor after correcting the detection value of the color component. The light source device according to claim 1. The light source unit is
A laser light source for emitting blue laser light;
A fluorescent part that converts a part of the blue laser light into fluorescence containing the red component and the green component, and emits mixed color light containing the fluorescence and the remainder of the blue laser light, and
The control unit controls the amount of current supplied to the laser light source based on the detection value of each color component detected by the optical sensor so that the color temperature of the light emitted from the light source unit becomes a predetermined value. The light source device according to any one of claims 1 to 4. A brightness sensor that receives a part of the light emitted from the light source unit and detects the brightness of the laser light source;
The controller controls the brightness sensor at the time when the second characteristic data is acquired with respect to the detected value of the brightness of the laser light source detected by the brightness sensor at the time when the first characteristic data is acquired. The light source device according to claim 5, wherein the second characteristic data is corrected based on a ratio of detected brightness values of the laser light source. The light source device according to any one of claims 1 to 6,
An image forming unit that forms an image by modulating light emitted from the light source device based on an input video signal;
A projection optical system that projects an image formed by the image forming unit. In response to the supply of current, it emits mixed-color light including a red component, a green component, and a blue component, and a part of the emitted light of the light source unit in which the amount and ratio of each color component change according to the amount of supply current An optical sensor correction method that separates a component, a green component, and a blue component and detects the light amount of each color component,
For at least one color component of the red component, the green component, and the blue component, first characteristic data indicating a change in detection value of the photosensor with respect to a change in the amount of current supplied to the light source unit is stored in advance.
At an arbitrary timing, the amount of current supplied to the light source unit is changed stepwise to obtain a detection value of the photosensor for each step for the at least one color component. Second characteristic data indicating a change in the detection value of the optical sensor with respect to the change is acquired, and the at least one detected by the optical sensor based on a difference between the second characteristic data and the first characteristic data. A photosensor correction method that corrects the detected values of two color components.