JP2020052232A - Light source device and image projection device - Google Patents

Abstract

To provide a light source device capable of reducing startup time at hot start when a light source that may generate COD is used.SOLUTION: The light source device includes: a first light source 10r; and a control means 17 that controls the drive of the first light source. The control means is configured to store the lighting time from the last lighting to the turning off of the first light source, obtain the turn-off time that has elapsed since the light was turned off, and when turning on the first light source after turning off, control the drive current or drive voltage to be supplied to the first light source depending on the lighting time or the turn-off time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light source device suitable for an image projection device such as a liquid crystal projector.

  2. Description of the Related Art A laser diode (LD) is used as a light source in an image projection apparatus (hereinafter, referred to as a projector) that modulates an image of light emitted from a light source by a light modulation element such as a liquid crystal panel and projects the light on a projection surface such as a screen. There is something. Some of such projectors use a plurality of LDs (blue LD and red LD) that emit light of different wavelengths, as disclosed in Patent Document 1.

  However, the red LD has a property of easily causing optical damage (COD: Catastrophic Optical Damage) when the temperature is particularly low, as compared with the blue LD. For this reason, at the start of lighting of the red LD (at a low temperature), the drive current of the red LD is lowered to increase the temperature while suppressing the occurrence of COD, and the drive current is increased after the temperature is sufficiently increased. Control is performed.

JP 2016-224304 A

  However, in the hot start in which the red LD is turned on immediately after being turned off, if the drive current is increased stepwise as described above even though the red LD is at a high temperature at which COD does not occur, the hot start is started. Sometimes, the time until image projection becomes possible (startup time) becomes long.

  The present invention provides a light source device capable of shortening a start-up time at the time of a hot start when a light source that can generate COD is used.

  A light source device according to one aspect of the present invention includes a first light source and a control unit that controls driving of the first light source. The control means stores the lighting time from the previous lighting to the turning off of the first light source, acquires the turning-off time elapsed after turning off the light source, and sets the lighting time and the turning-off time when turning on the first light source after turning off. The driving current or the driving voltage supplied to the first light source is controlled in accordance with Note that an image projection device using the above light source device also constitutes another aspect of the present invention.

  Further, a control method as another aspect of the present invention is applied to a light source device having a first light source. The control method includes the steps of: storing a lighting time of the first light source from the previous lighting until the light is turned off; obtaining a light-off time elapsed after the light is turned off; and turning on the first light source after the light is turned off. Controlling a drive current or a drive voltage supplied to the first light source according to the time and the light-off time.

  Note that a computer program that causes a computer of the light source device having the first light source to execute processing according to the control method also constitutes another aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, when using the light source which can generate | occur | produce COD, the starting time at the time of a hot start can be shortened.

FIG. 1 is a block diagram illustrating a configuration of a projector according to an embodiment of the invention. 6 is a flowchart illustrating processing according to the embodiment. FIG. 4 is a diagram showing control of a drive current in the embodiment. FIG. 3 is a diagram showing a temperature rise model and a temperature fall model of a light source in the example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration of a projector (image projection device) 1 including a light source device according to an embodiment of the present invention. 10r is a red light source as a first light source, and 10b is a blue light source as a second light source having a different emission wavelength range from the red light source 10r. 11r is a red light source heat sink, and 11b is a blue light source heat sink. 12r is a red light source driving unit, and 12b is a blue light source driving unit. Reference numeral 17 denotes a control unit as control means, which includes a memory 13, a time acquisition unit 14, and a light source drive setting unit 15. Reference numeral 16 denotes an environmental temperature sensor as temperature detecting means, and reference numeral 18 denotes an image forming unit.

  Red light source 10r, blue light source 10b, red light source heat sink 11r, blue light source heat sink 11b, red light source drive unit 12r, blue light source drive unit 12b, control unit 17 (memory 13, time acquisition unit 14, and light source drive setting unit 15) and environment A light source device is constituted by the temperature sensor 16.

  The red light source 10r is a semiconductor laser that emits light in the red wavelength range (red light). The blue light source 10b is a semiconductor laser that emits light in the blue wavelength range (blue light).

  The control unit 17 is configured by a computer such as a CPU and controls the entire projector 1. In the control unit 17, the memory 13 stores various data and computer programs. The various data includes data on the lighting time and turning off time of the red light source 10r, and data on the temperature rise model and the temperature fall model of the red light source 10r. The lighting time, the lighting time, the temperature rise model and the temperature fall model will be described later. The time counter 14 counts time. The light source drive setting unit 15 sets a drive current to be supplied to the red light source 10r and the blue light source 10b.

  The environmental temperature sensor 16 detects an environmental temperature that is the temperature around the projector 1 and outputs information on the detected environmental temperature to the control unit 17.

  The red light source driving unit 12r supplies a driving current corresponding to the current set value set by the light source driving setting unit 15 to the red light source 10r to drive it. The blue light source drive unit 12b supplies a drive current corresponding to the current set value set by the light source drive setting unit 15 to the blue light source 10b to drive it. In this embodiment, the case where the drive currents of the red light source 10r and the blue light source 10b are controlled will be described, but the drive voltage supplied to these may be controlled.

  The image forming unit 18 includes a light modulation element 18a such as a liquid crystal panel or a digital micromirror device, and an optical system 18b that guides light (illumination light) from the red light source 10r and the blue light source 10b to the light modulation element 18a. The control section 17 drives the light modulation element 18a in accordance with the video signal input to the projector 1 to modulate the illumination light and generate image light. The image forming unit 18 projects the image light generated by the light modulation element 18a onto a projection surface 20 such as a screen via a projection lens 18c. Thereby, a projection image is displayed.

  Next, a light source driving process (control method) performed by the control unit 17 in the present embodiment will be described with reference to the flowchart of FIG. The control unit 17 executes this processing according to the computer program read from the memory 13. FIG. 3 shows a temperature rise model that models a temperature rise process when the red light source 10r is turned on from a light-off state, and a temperature decrease model that models a temperature fall process when the red light source 10r is turned off from a light-on state. Is shown. The projector 1 of this embodiment has a first projection mode and a second projection mode as a plurality of projection modes. In the present embodiment, the first projection mode is a projection mode in which the luminance (light amount) of the light source is set to the maximum. Further, the second projection mode is a projection mode in which the luminance of the light source is set lower than in the first projection mode.

  The control unit 17 can control the red light source 10r in a plurality of light source driving modes, and has a first light source driving mode and a second light source driving mode. In the first projection mode, the red light source 10r is driven in the first light source driving mode, and in the second projection mode, the red light source 10r is driven in the second light source driving mode.

  The solid line shows the temperature rise and temperature fall model for the first light source drive mode, and the dashed line shows the temperature rise and temperature fall model for the second light source drive mode. The two-dot chain line shows the temperature rise and temperature decrease models used when the environmental temperature is high in the first light source drive mode.

  In step 101 of FIG. 2, the control unit 17 checks whether or not there is a lighting command according to a user operation on the projector 1, and upon receiving the lighting command, proceeds to step 102.

  In step 102, the control unit 17 acquires the previous lighting time Δon stored in the memory 13. The lighting time Δon indicates the length of time from turning on to turning off the red light source 10r. The control unit 17 obtains the light-on time and the light-off time of the red light source 10r from the time counter 14, calculates the light-on time 差分 on as a difference therebetween, and stores the calculated light-on time Тon in the memory 13. In addition, the control unit 17 causes the memory 13 to store in which projection mode the projection was performed (in which light source driving mode). In this step, the control unit 17 acquires the previous lighting time Тon stored in the memory 13 as the length of time from turning on to turning off the red light source 10r before receiving the lighting instruction this time.

  Next, in step 103, the control unit 17 acquires the current time from the time counter 14 and stores the current time in the storage unit 13 as the current lighting time.

  Next, in step 104, the control unit 17 determines the difference between the previous turn-off time and the current turn-on time stored in the memory 13 (that is, the time elapsed from the last turn-off to the current turn-on) as the turn-off time Toff. Is calculated as

  Next, in step 105, the light source drive setting unit 15 of the control unit 17 acquires the currently set projection mode and acquires the current environmental temperature of the installation location of the projector 1 from the environmental temperature sensor 16.

  Next, in step 106, the light source drive setting unit 15 determines, based on the temperature rise model of the red light source 10 r stored in the memory 13, the time length until the temperature of the lit red light source 10 r reaches the predetermined temperature A. Obtain a first time T1. The predetermined temperature A is a temperature at which optical damage (CОD) does not occur in the red light source 10r even when a predetermined drive current (rated current) is supplied to the red light source 10r to turn on the red light source 10r. Therefore, the first time T1 is a time required for the temperature of the red light source 10r to rise to a temperature at which CОD does not occur. The predetermined drive current is a drive current for driving the light source in the set light source drive mode.

  At this time, when the current projection mode is the first projection mode, the light source drive setting unit 15 acquires T1a as the first time Т1, using the temperature rise model shown by the solid line in FIG. . When the current projection mode is the second projection mode, the light source drive setting unit 15 obtains T1b as the first time Т1, using the temperature rise model indicated by the dashed line in FIG. . Further, when the current projection mode is the first projection mode and the environmental temperature is higher than the assumed temperature in the first projection mode, the second projection mode is performed using the temperature rise model indicated by the two-dot chain line in FIG. T1c is acquired as the time of one # 1.

  Next, in step 107, the light source drive setting unit 15 determines, based on the temperature decrease model of the red light source 10 r stored in the memory 13, the length of time until the temperature of the previously turned off red light source 10 r decreases to the predetermined temperature A. As a second time T2. At this time, if the projection mode at the time of the previous lighting is the first projection mode, the light source drive setting unit 15 uses the temperature drop model indicated by the solid line in FIG. To get.

  When the current projection mode is the second projection mode, the light source drive setting unit 15 obtains T2b as the second time Т2 using the temperature drop model indicated by the dashed line in FIG. . Further, when the current projection mode is the first projection mode and the ambient temperature is higher than the assumed temperature in the first projection mode, the second projection mode is performed using the temperature drop model indicated by the two-dot chain line in FIG. Then, T2c is acquired as the time period of Т2.

  In this embodiment, the case where both # 1 and # 2 are changed according to the light source driving mode and the environmental temperature is described. However, at least one of # 1 and # 2 may be changed.

  Next, in step 108, the light source drive setting unit 15 compares Ton with T1, and if Ton is longer than T1, proceeds to step 109, and if Ton is shorter than T1 (T1a, T1b or T1c), proceeds to step 110. .

  In Step 109, the light source drive setting unit 15 compares Toff with T2. If Toff is longer than T2, the process proceeds to Step 110. If Toff is shorter than the second time T2 (T2a, T2b or T2c), Step 111 is performed. Proceed to.

  In step 110, the light source drive setting unit 15 sets the target drive current of the red light source 10r for a predetermined time to a low current lower than the rated current (predetermined value), and further sets the target drive current after the predetermined time to the rated current. Set to. That is, when the previous lighting time Ton is shorter than the first time T1, and when the light-off time Δoff is longer than the second time # 2, the control unit 17 sets the red light source 10r as shown in FIG. The drive current is controlled to increase to the rated current over a predetermined time. That is, the red light source 10r is started at a low speed. The predetermined time is set to a time during which the temperature of the red light source 10r slowly rises to the predetermined temperature A so that CОD does not occur in the red light source 10r. Then, the control unit 17 proceeds to step 112.

  On the other hand, in step 111, the light source drive setting unit 15 sets the drive current of the red light source 10r to the rated current. Accordingly, when the previous lighting time Ton is longer than the first time T1 and the light-off time Toff up to the current lighting instruction is shorter than the second time T2, the control unit 17 returns to FIG. As shown, the drive current of the red light source 10r is controlled to increase to the rated current in a time shorter than the predetermined time. That is, the red light source 10r is started at high speed. Thus, when the red light source 10r that can generate COD is used, the startup time at the time of hot start can be reduced. Then, the control unit 17 proceeds to step 112.

  In step 112, the control unit 17 checks whether or not there is a light-off instruction according to a user operation on the projector 1, and upon receiving the light-off instruction, proceeds to step 113.

  In step 113, the control unit 17 stores the time at which the current light-off instruction is received from the time counter 14 (the previous light-off time in step 102 of the next routine) in the memory 13, and returns to step 101.

  Regarding the blue light source 10b, a rated current is set as a target drive current from the beginning regardless of Ton or Toff. That is, the blue light source 10b is always started at high speed.

When the lighting time Тon is longer than the first time Т1, the second time Т2 may be changed according to the lighting time. Specifically, the second time # 2 may be set longer as the lighting time $ on is longer.
(Other Examples)
The present invention supplies a program for realizing one or more functions of the above-described embodiments to a system or an apparatus via a network or a storage medium, and one or more processors in a computer of the system or the apparatus read and execute the program. This processing can be realized. Further, it can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

  Each of the embodiments described above is only a typical example, and various modifications and changes can be made to each embodiment when the present invention is implemented.

1 Projector 10r Red light source 10b Blue light source 13 Memory 14 Time counter 15 Light source drive setting unit 17 Control unit

Claims (13)

A first light source;
Control means for controlling the driving of the first light source,
The control means includes:
Storing a lighting time of the first light source from the previous lighting to the extinguishing,
Obtain the extinguishing time elapsed after the extinguishing,
When the first light source is turned on after the light is turned off, a driving current or a driving voltage supplied to the first light source is controlled according to the lighting time and the light-off time. The control means includes:
If the lighting time is shorter than the first time, control the drive voltage or the drive current to increase to a predetermined value over a predetermined time,
When the light-on time is longer than the first time and the light-off time is shorter than the second time, control is performed such that the drive voltage or the drive current is increased to the predetermined value in a time shorter than the predetermined time. The light source device according to claim 1, wherein:   The control means controls the drive voltage or the drive current to increase to the predetermined value over the predetermined time when the turn-off time is longer than the second time. 3. The light source device according to 2.   3. The device according to claim 2, wherein the first time is a time required until the temperature of the first light source turned on from the unlit state rises to a temperature at which no optical damage occurs to the first light source. Or the light source device according to 3. The control means includes:
The light source device according to any one of claims 2 to 4, wherein when the lighting time is longer than the first time, the second time is changed according to the lighting time. Having a second light source having a different emission wavelength range from the first light source,
When the second light source is turned on, the control means sets a drive current or a drive voltage supplied to the second light source to a predetermined value shorter than the predetermined time regardless of the lighting time and the light-off time. The light source device according to claim 2, wherein the light source device is controlled so as to increase the light source device.   The control means sets the first time using data of a temperature rise model when the first light source is turned on, and sets the first time using data of a temperature decrease model when the first light source is turned off. The light source device according to any one of claims 2 to 6, wherein the second time is set. The control means includes:
The drive of the first light source can be controlled in a plurality of drive modes,
The light source device according to claim 2, wherein at least one of the first and second times is changed according to the drive mode. Having temperature detection means for detecting the environmental temperature,
The light source device according to claim 2, wherein the control unit changes at least one of the first and second times according to the environmental temperature.   The light source device according to any one of claims 1 to 9, wherein the first light source is a laser diode that emits light in a red wavelength range. A light source device according to any one of claims 1 to 10,
A light modulation element for modulating light from the light source device,
An image projection device for projecting an image with light from the light modulation element. A method for controlling a light source device having a first light source,
Storing the lighting time of the first light source from the previous lighting to the extinguishing;
Obtaining a light-off time elapsed after the light-off,
When the first light source is turned on after the light is turned off, the method further comprises a step of controlling a drive current or a drive voltage supplied to the first light source according to the turn-on time and the turn-off time. A method for controlling a light source device.   A computer program for causing a computer of a light source device having a first light source to execute a process according to the control method according to claim 12.