JP2010286576A - Projector and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector which restrains useless power consumption; and to provide a method for controlling the projector. <P>SOLUTION: The projector 1 includes: an image information input part 33 to which image information is inputted; light source devices 11R, 11G and 11B which emit light; light-modulating devices 14R, 14G and 14B which modulate the light emitted from the light source devices 11R, 11G and 11B on the basis of the image information to form an image; a projection lens 16 which projects the image formed by the light-modulating devices 14R, 14G and 14B; a variation-detecting part 35 which detects the presence or absence of a variation in the image; and a control part 30 which changes the lighting states of the light source devices 11R, 11G and 11B to a power consumption-lowered state when the variation-detecting part 35 detects that there is no variation in the image. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a projector that modulates and projects light emitted from a light source device and a control method therefor.

  In a projector that modulates light emitted from a light source device in accordance with input image information to form an image and projects the image on a screen or the like in an enlarged manner, the light source device according to whether or not image information is input A projector (projection display device) that controls the lighting state of the projector has been proposed (for example, Patent Documents 1 and 2). According to the projectors described in Patent Document 1 and Patent Document 2, when there is no input of image information, that is, when there is no image to be projected, the light source device is turned off or the luminance is decreased, which is useless. It becomes possible to suppress power consumption.

JP 2001-133880 A JP 2003-5147 A

  However, since the projectors described in Patent Document 1 and Patent Document 2 reduce power consumption of the light source device when no image information is input, the projector is left in a state where image information is continuously input. It is not effective for etc. That is, there is a problem that even if no one is viewing the projected image, wasteful power is consumed as long as image information is input.

  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 projector according to this application example modulates an image information input unit to which image information is input, a light source device that emits light, and light emitted from the light source device based on the image information. A light modulation device that forms an image, a projection optical system that projects the image formed by the light modulation device, a detection unit that detects the presence or absence of a change in the image based on the image information, And a control unit that switches the lighting state of the light source device to a low power consumption state when the detection unit detects that the image has not changed.

  According to this projector, when the detection unit detects that the image has not changed, the control unit switches the lighting state of the light source device to a state with low power consumption. It is possible to suppress wasteful power consumption when the input continues.

  Application Example 2 In the projector according to the application example, the detection unit calculates a reference value based on the image information at intervals, and determines whether the image has changed based on a comparison result of the reference value. It is desirable to detect.

  According to this projector, since the detection unit detects the presence or absence of a change in the image by comparing the reference value based on the image information, the load when performing the detection is reduced compared to the case of directly comparing the image information. It becomes possible to do.

  Application Example 3 In the projector according to the application example, it is preferable that the detection unit divides the image into a plurality of regions and calculates the reference value for each region.

  According to this projector, since the detection unit divides the image into a plurality of regions and calculates the reference value for each region, the calculation and comparison of the reference value can be performed in parallel, and detection can be performed in a short time. Can be performed.

  Application Example 4 In the projector according to the application example described above, the control unit may turn off the light source device when the detection unit detects that the image has not changed.

  Application Example 5 In the projector according to the application example described above, the control unit may reduce the brightness of the light source device when the detection unit detects that the image has not changed. .

  Application Example 6 In the projector according to the application example described above, the control unit may cause the light source device to blink when the detection unit detects that the image has not changed.

  Application Example 7 In the projector according to the application example, the light source device includes a plurality of light emitting elements, and the control unit detects that the image has not changed when the detection unit detects that the image has not changed. A part of the plurality of light emitting elements may be turned off.

  If the detector detects that the image has not changed and the light source device is completely turned off, the user may be mistaken for the projector being turned off. When reducing the brightness of the device, blinking the light source device, or turning off some light-emitting elements, it is easy for the user to recognize that the power consumption is suppressed .

  Application Example 8 In the projector according to the application example described above, the projector further includes a light source driving unit that drives the light source device, and the control unit detects the change in the image when the detection unit detects that the image has not changed. You may make it stop the electric power supply with respect to a light source drive part.

  According to this projector, when the detection unit detects that the image has not changed, the control unit stops power supply to the light source driving unit that drives the light source device, and thus further suppresses power consumption. It becomes possible.

  Application Example 9 In the projector according to the application example, it is preferable that the light source device includes a solid light source.

  According to this projector, since the light source device includes the solid light source, it is possible to instantaneously switch the lighting state as compared with the case where a discharge lamp is used.

  Application Example 10 In the projector according to the application example described above, the light source device may operate using a battery as a power source.

  Application Example 11 A projector control method according to this application example includes a projector that modulates light emitted from a light source device based on input image information to form an image, and projects the formed image. In the control method, when the detection step detects whether or not the image has changed based on the image information, and the detection step detects that the image has not changed, the light source device is turned on. A light source control step of switching the state to a state of low power consumption.

  According to this projector control method, when it is detected that the image has not changed, the lighting state of the light source device is switched to a state of low power consumption, so that image information is continuously input without changing the image. This makes it possible to suppress wasteful power consumption.

  When the projector and the control method described above are constructed using a computer provided in the projector, the form and the application example described above are a program for realizing the function, or the program is stored in the computer. It is also possible to constitute in the form of a recording medium or the like recorded so as to be readable by the user. Recording media include flexible disks, hard disks, optical disks such as CDs and DVDs, magneto-optical disks, memory cards and USB memories equipped with nonvolatile semiconductor memory, projector internal storage devices (semiconductor memories such as RAM and ROM), etc. Various media readable by the computer can be used.

1 is a block diagram illustrating a schematic configuration of a projector according to a first embodiment. Explanatory drawing for demonstrating the image projection part of 1st Embodiment in detail. 6 is a flowchart for explaining the operation of the projector in a normal mode. The flowchart explaining operation | movement of the projector in energy saving mode. The block diagram which shows schematic structure of the projector of 2nd Embodiment. Explanatory drawing for demonstrating the image projection part of 3rd Embodiment. Explanatory drawing for demonstrating the light source device which concerns on a modification.

(First embodiment)
A projector that modulates light emitted from a light source device to form an image and projects the image on an external screen or the like will be described below with reference to the drawings.
The projector according to the present embodiment includes a normal mode in which the light source device is turned on at a predetermined brightness based on an input operation by the user, and an energy saving that reduces power consumption by making the light emission luminance of the light source device darker than in the normal mode. The mode can be switched. When the user views the projected image, the normal mode is set, and when the image viewing is temporarily interrupted, the energy saving mode is set.

FIG. 1 is a block diagram showing a schematic configuration of the projector.
As shown in FIG. 1, the projector 1 includes an image projection unit 10, a control unit 30, a storage unit 31, an input operation unit 32, an image information input unit 33, an image processing unit 34, a drive circuit 36, a power circuit 39, and the like. Has been.

  The image projection unit 10 includes three light source devices 11R, 11G, and 11B configured with semiconductor lasers, three light modulation devices 14R, 14G, and 14B, and a projection lens 16 as a projection optical system. . The image projection unit 10 modulates the light emitted from the light source devices 11R, 11G, and 11B by the light modulation devices 14R, 14G, and 14B to form image light, and projects the image light from the projection lens 16. An image is displayed on an external screen SC or the like.

FIG. 2 is an explanatory diagram for explaining the image projection unit 10 in more detail, and shows an optical path of light emitted from the light source devices 11R, 11G, and 11B.
As shown in FIG. 2, the image projection unit 10 includes, in addition to the three light source devices 11R, 11G, and 11B, the three light modulation devices 14R, 14G, and 14B, and the projection lens 16, the diffusion elements 12R, 12G, and 12B, field lenses 13R, 13G, and 13B, a cross dichroic prism 15 and the like.

  The light source device 11R is a light source device that emits red light, and the red light emitted from the light source device 11R illuminates the light modulation device 14R via the diffusion element 12R and the field lens 13R. The diffusing element 12R adjusts the shape of the illumination range and makes the light amount distribution within the illumination range uniform. For example, a computer generated hologram (CGH) that is a diffractive optical element can be used. . The field lens 13R is an optical element that collimates the light from the light source device 11R and guides it to the light modulation device 14R.

  The light source device 11G is a light source device that emits green light, and the green light emitted from the light source device 11G illuminates the light modulation device 14G via the diffusion element 12G and the field lens 13G. The light source device 11B is a light source device that emits blue light, and the blue light emitted from the light source device 11B illuminates the light modulation device 14B through the diffusion element 12B and the field lens 13B. The functions of the diffusion elements 12G and 12B and the field lenses 13G and 13B are the same as those of the diffusion element 12R and the field lens 13R, respectively.

  Each of the light modulation devices 14R, 14G, and 14B includes a transmissive liquid crystal panel in which liquid crystal is sealed between a pair of transparent substrates, and is driven on the inner surface of the transparent substrate for each minute region (pixel) with respect to the liquid crystal. Transparent electrodes (pixel electrodes) to which a voltage can be applied are formed in a matrix. As the transmission type liquid crystal panel, for example, a high temperature poly silicon (HTPS) TFT liquid crystal panel can be used.

  Here, when a driving voltage based on image information is applied to each pixel of the liquid crystal panel, the light incident on the light modulation devices 14R, 14G, and 14B is modulated for each pixel in accordance with the driving voltage, and becomes a driving voltage. Each pixel is transmitted with a corresponding transmittance. Thereby, image light having gradation is formed for each color light. Image light composed of light of each color emitted from the light modulation devices 14R, 14G, and 14B enters the cross dichroic prism 15.

  The cross dichroic prism 15 is provided with a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light in a substantially X shape along the interface of four right-angle prisms. The image light of each color formed by the modulators 14R, 14G, and 14B is synthesized by these dielectric multilayer films. The image light synthesized by the cross dichroic prism 15 is emitted from the exit surface as color image light and enters the projection lens 16.

  The projection lens 16 is disposed on the exit surface side of the cross dichroic prism 15 and enlarges and projects the image light synthesized by the cross dichroic prism 15. The image light emitted from the projection lens 16 is projected onto an external screen SC or the like.

  Returning to FIG. 1, the control unit 30 includes a CPU (Central Processing Unit), a RAM (Random Access Memory) used for temporary storage of various data, and the like, and operates according to a control program stored in the storage unit 31. As a result, the overall operation of the projector 1 is controlled. That is, the control unit 30 functions as a computer together with the storage unit 31.

  The storage unit 31 is configured by a rewritable nonvolatile memory such as a flash memory or an FeRAM (Ferroelectric RAM). The storage unit 31 stores a control program for controlling the operation of the projector 1, various setting data for defining operation conditions of the projector 1, and the like.

  The input operation unit 32 receives an input operation by the user, and includes a plurality of operation keys for the user to give various instructions to the projector 1. The operation keys provided in the input operation unit 32 include a power key for switching on and off the power, a mode switching key for switching between the normal mode and the energy saving mode, and the like. When the user operates various operation keys of the input operation unit 32, the input operation unit 32 outputs an operation signal corresponding to the operation content of the user to the control unit 30. The input operation unit 32 may be configured using a remote control (not shown) capable of remote operation. In this case, the remote control transmits an infrared operation signal corresponding to the user's operation content, and a remote control signal receiving unit (not shown) receives this and transmits it to the control unit 30.

  The image information input unit 33 includes an input terminal (not shown), and image information output from an external image output device such as a video playback device or a personal computer is input to the input terminal. The image information input to the image information input unit 33 is supplied to the image processing unit 34.

  The image processing unit 34 converts the image information input from the image information input unit 33 into image information representing the gradation of each pixel of the light modulation devices 14R, 14G, and 14B in units of frames (screen units). Here, the converted image information is for each color light of R, G, and B, and is composed of a plurality of pixel values corresponding to all the pixels of each of the light modulation devices 14R, 14G, and 14B. The pixel value determines the light transmittance of the corresponding pixel, and the intensity (gradation) of light emitted from each pixel is defined by the pixel value. The image processing unit 34 outputs the converted image information to the modulation driving unit 37 of the driving circuit 36.

  In addition, the image processing unit 34 includes a change detection unit 35 as a detection unit. Based on an instruction from the control unit 30, whether or not the image information has changed between different frames, that is, over time. It is possible to detect the presence or absence of accompanying image changes. Instead of directly comparing the image information, the change detection unit 35 of the present embodiment uses the lower 8 bits of the sum of all pixel values constituting one frame as a reference value, and compares this reference value between different frames. If the reference values match, it is determined that the image has not changed, and if the reference values do not match, it is determined that the image has changed. The change detection unit 35 is provided with a memory (not shown) for storing reference values calculated in the past. When the change detection unit 35 receives an instruction to compare images from the control unit 30, the change detection unit 35 calculates the reference value of the latest frame, compares it with the reference value stored in the memory, and compares the comparison result with the control unit. 30 is notified. Thereafter, the change detection unit 35 updates the contents of the memory by storing (overwriting) the newly calculated reference value in the memory.

The drive circuit 36 includes a modulation drive unit 37 and a light source drive unit 38.
The modulation driving unit 37 drives the light modulation devices 14R, 14G, and 14B according to the image information input from the image processing unit 34, and causes the light modulation devices 14R, 14G, and 14B to form image light according to the image information. Thereby, the image light based on the image information is projected from the projection lens 16 onto the screen SC.

  The light source driving unit 38 controls power supply to the light source devices 11R, 11G, and 11B based on an instruction from the control unit 30, and switches the lighting state of the light source devices 11R, 11G, and 11B. The light source drive unit 38 can turn on, turn off, or blink the light source devices 11R, 11G, and 11B, and controls the power supplied to the light source devices 11R, 11G, and 11B to control the light emission luminance at the time of lighting ( Brightness) can be adjusted. For this reason, when the mode switch key of the input operation unit 32 is operated by the user, the light source driving unit 38 can switch between the normal mode and the energy saving mode based on an instruction from the control unit 30.

  The power supply circuit 39 is supplied with commercial power such as AC 100V from the outside. The power supply circuit 39 converts a commercial power supply, which is an AC power supply, into a DC power supply having a predetermined voltage, and supplies power to each part of the projector 1 including the drive circuit 36.

Next, the operation of the projector 1 according to this embodiment will be described.
FIG. 3 is a flowchart for explaining the operation of the projector 1 in the normal mode. In the normal mode, the control unit 30 executes the flow shown in FIG. 3 periodically (for example, at a rate of once per second). When the state in which the image does not change continues for a predetermined time, the projector 1 shifts to the energy saving mode automatically, that is, without depending on the user's input operation.

  As shown in FIG. 3, in step S <b> 101, the control unit 30 instructs the change detection unit 35 to detect the presence / absence of an image change. Upon receiving this instruction from the control unit 30, the change detection unit 35 calculates the reference value of the latest frame and compares it with the reference value stored in the memory. Then, the comparison result is notified to the control unit 30, and the newly calculated reference value is stored in the memory.

  In subsequent step S <b> 102, the control unit 30 determines whether the image has changed over time based on the comparison result of the change detection unit 35. If the image has changed, the process proceeds to step S103, and if the image has not changed, the process proceeds to step S104.

  When the image changes with time and the process proceeds to step S103, the control unit 30 resets a variable (counter) for measuring the time during which the image has not changed to 0 and ends the flow. This counter is stored in a RAM (not shown) in the control unit 30.

  On the other hand, when the image does not change and the process proceeds to step S104, the control unit 30 increments the counter described above by one, and in subsequent step S105, the control unit 30 determines that the incremented counter has a predetermined value ( It is determined whether or not the upper limit value has been reached. If the counter reaches the upper limit value, the process proceeds to step S106. If the counter has not reached the upper limit value, the flow ends.

  When the counter reaches the upper limit value and the process proceeds to step S106, the control unit 30 instructs the light source driving unit 38 to switch the projector 1 from the normal mode to the energy saving mode and ends the flow. When receiving the instruction from the control unit 30, the light source driving unit 38 controls the power supplied to the light source devices 11R, 11G, and 11B to reduce the light emission luminance (brightness) at the time of lighting. As a result, the projector 1 is switched to the energy saving mode.

  Since the projector 1 operates as described above, for example, when the above flow is executed at a rate of once per second, if the upper limit value of the counter is set to 180, the image is displayed for 3 minutes ( If it does not change (180 seconds), it will switch to the energy saving mode.

  FIG. 4 is a flowchart for explaining the operation of the projector 1 in the energy saving mode. In the energy saving mode, the control unit 30 executes the flow shown in FIG. 4 periodically (for example, at a rate of once per second). When the image changes, the projector 1 returns to the normal mode automatically, that is, without depending on the user's input operation.

  As shown in FIG. 4, in step S <b> 201, the control unit 30 instructs the change detection unit 35 to detect presence / absence of an image change. Upon receiving this instruction from the control unit 30, the change detection unit 35 calculates the reference value of the latest frame and compares it with the reference value stored in the memory. Then, the comparison result is notified to the control unit 30, and the newly calculated reference value is stored in the memory.

  In subsequent step S <b> 202, the control unit 30 determines whether the image has changed over time based on the comparison result of the change detection unit 35. If the image has changed, the process proceeds to step S203. If the image has not changed, the flow ends.

  When the image changes and the process proceeds to step S203, the control unit 30 instructs the light source driving unit 38 to switch the projector 1 from the energy saving mode to the normal mode, and ends the flow. When receiving the instruction from the control unit 30, the light source driving unit 38 controls the power supplied to the light source devices 11R, 11G, and 11B to increase the light emission luminance (brightness) at the time of lighting. As a result, the projector 1 switches to the normal mode, and thereafter periodically executes the flow shown in FIG.

  In addition, when the input operation part 32 is operated by the user, you may make it return to normal mode. Further, when the energy saving mode continues for a predetermined time, the power may be shifted to the off state (standby state).

  As described above, according to the projector 1 of the present embodiment, the following effects can be obtained.

  (1) According to the projector 1 of the present embodiment, when the state in which the image has not changed continues for a predetermined time, the control unit 30 instructs the light source driving unit 38 to provide the light source devices 11R and 11G. , 11B, the projector 1 is shifted to the energy saving mode. For this reason, it is possible to suppress wasteful power consumption when image information continues to be input without changing the image.

  (2) According to the projector 1 of the present embodiment, the change detection unit 35 calculates a reference value based on image information (pixel value) constituting one frame, and compares the reference value between different frames. Since the presence / absence of an image change is detected, it is possible to reduce the load at the time of detection compared to a case where image information (pixel value) is directly compared between different frames.

  In the present embodiment, in the energy saving mode, the light emission luminance of the light source devices 11R, 11G, and 11B is reduced (darkened) compared to the normal mode. However, the light source devices 11R, 11G are not limited to this mode. , 11B may be turned off, or the light source devices 11R, 11G, 11B may be blinked. Even in these cases, it is possible to obtain the effect of reducing the power consumption as compared with the normal mode.

  In the present embodiment, step S101 for detecting the presence or absence of a change in the image corresponds to a detection step, and step S106 for switching to the energy saving mode corresponds to a light source control step.

(Second Embodiment)
Next, a projector according to a second embodiment will be described. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment, and the detailed description is abbreviate | omitted.

FIG. 5 is a block diagram illustrating a schematic configuration of the projector 1 according to the present embodiment.
As shown in FIG. 5, the projector 1 of the present embodiment includes a power supply control unit 40 in addition to the components of the first embodiment. The power supply control unit 40 controls power supply from the power supply circuit 39 to the drive circuit 36 based on an instruction from the control unit 30. Other configurations are the same as those in the first embodiment.

  When switching from the normal mode to the energy saving mode in step S106 (see FIG. 3), the control unit 30 instructs the power supply control unit 40 to stop the supply of power to the drive circuit 36. As a result, the operations of the modulation driving unit 37 and the light source driving unit 38 are stopped, and the light source devices 11R, 11G, and 11B are turned off. In addition, when switching from the energy saving mode to the normal mode in step S203 (see FIG. 4), the control unit 30 instructs the power supply control unit 40 to restart the supply of power to the drive circuit 36. As a result, the modulation driving unit 37 and the light source driving unit 38 resume their operations, and the light source devices 11R, 11G, and 11B are turned on. Operations other than step S106 and step S203 are the same as in the first embodiment (see FIGS. 3 and 4).

As described above, according to the projector 1 of the present embodiment, the following effects can be obtained in addition to the effects of the first embodiment.
According to the projector 1 of the present embodiment, since the power supply to the drive circuit 36 is stopped when the image shifts to the energy saving mode without changing the image, the power consumption can be further suppressed.

  In the present embodiment, in the energy saving mode, the operations of both the modulation drive unit 37 and the light source drive unit 38 are stopped, but the operation of the modulation drive unit 37 is not necessarily stopped. In the energy saving mode of the present embodiment, power may be intermittently supplied to the light source driving unit 38 to blink the light source devices 11R, 11G, and 11B. Even in this case, it is possible to obtain the effect of reducing the power consumption as compared with the normal mode.

(Third embodiment)
Next, a projector according to a third embodiment will be described. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment and 2nd Embodiment, and the detailed description is abbreviate | omitted.

FIG. 6 is an explanatory diagram for explaining the image projection unit 10 of the present embodiment. The block diagram is common to the first embodiment (see FIG. 1).
As shown in FIG. 6, the projector 1 according to the present embodiment is a single-plate projector in which the image projection unit 10 includes only one light modulation device 14, and the diffusion element 12 that guides light to the light modulation device 14 and the field. One lens 13 is also provided.

  The light source devices 11R, 11G, and 11B are configured to include a semiconductor laser, and emit light toward the reflection mirror 17, the first dichroic mirror 18, and the second dichroic mirror 19, respectively. The red light emitted from the light source device 11 </ b> R is reflected by the reflection mirror 17 and travels toward the first dichroic mirror 18. The first dichroic mirror 18 is an optical element that transmits red light and reflects green light. The green light emitted from the light source device 11G is reflected by the first dichroic mirror 18 and combined with red light. To the second dichroic mirror 19. The second dichroic mirror 19 is an optical element that transmits red light and green light and reflects blue light. The blue light emitted from the light source device 11B is reflected by the second dichroic mirror 19 to be red. Synthesized with light and green light. Then, the combined light of the red light, the green light, and the blue light illuminates the light modulation device 14 via the diffusion element 12 and the field lens 13.

  The light modulation device 14 of the present embodiment includes three sub-pixels that can transmit R light, G light, and B light in each pixel of the liquid crystal panel, and are emitted from the light source devices 11R, 11G, and 11B. The modulated light is modulated to form color image light. Then, the formed image light is projected from the projection lens 16 onto an external screen SC or the like.

  Also in the present embodiment, in the energy saving mode, power consumption is reduced by darkening, turning off, or blinking the light source devices 11R, 11G, and 11B. Further, as in the second embodiment, power consumption may be reduced by stopping the power supply to the drive circuit 36.

  As described above, according to the projector 1 of the present embodiment, the same effects as those of the first embodiment and the second embodiment can be obtained.

(Modification)
In addition, you may change the said embodiment as follows.

  In the above embodiment, the light source devices 11R, 11G, and 11B are provided with a semiconductor laser. However, the light emitting element provided in the light source device is not limited to the semiconductor laser, but is an LED (Light Emitting Diode) or EL (Electro Luminescence). ), Other solid light sources such as SLD (Super Luminescence Diode). It is also possible to employ a discharge-type light source lamp as the light source device. However, in order to instantaneously switch between the normal mode and the energy saving mode, that is, switching the lighting state of the light source device, it is desirable to employ a solid light source.

  In the embodiment described above, an example in which the light source devices 11R, 11G, and 11B are darkened or turned off in the energy saving mode is shown, but the present invention is not limited to this mode. For example, any one or two of the three light source devices 11R, 11G, and 11B may be turned off. Further, when the light source devices 11R, 11G, and 11B include a plurality of light emitting elements, respectively, the light source devices 11R, 11G, and 11B are darkened by turning off only some of the light emitting elements. Also good.

FIG. 7 is an explanatory diagram for explaining a light source device 11R according to a modification. Although not shown, the other light source devices 11G and 11B have the same configuration as the light source device 11R.
As shown in FIG. 7, the light source device 11R includes a plurality of light emitting elements (for example, LEDs) 20a, 20b, and 20c arranged in a matrix, and some of the light emitting elements 20a include the first light emitting element 20a. The other light emitting elements 20b and 20c are driven by the second light source driving unit 38b. In such a configuration, when switching to the energy saving mode, for example, the driving by the second light source driving unit 38b may be stopped. Or as shown in 2nd Embodiment, you may make it stop the electric power supply itself with respect to the 2nd light source drive part 38b.

  In the energy saving mode, a part of the light source devices 11R, 11G, and 11B or a part of the light emitting elements constituting the light source devices 11R, 11G, and 11B is turned off in a mode of turning off the light source device (light emitting element). If the switches are sequentially switched, it is possible to make the use history (usage time) uniform among a plurality of light source devices (light emitting elements), and it is possible to extend the lifetime of the light source devices 11R, 11G, and 11B. .

  Further, if the light source devices 11R, 11G, and 11B are completely turned off in the energy saving mode, the user may be mistaken for the projector 1 being turned off. However, the light source devices 11R, 11G, and 11B may be misunderstood. In the case of reducing the brightness of the light source, flashing the light source devices 11R, 11G, and 11B, or turning off a part of the light source devices 11R, 11G, and 11B or a part of the light emitting elements It is easy for the user to recognize that the power is suppressed.

  In the above embodiment, the lower 8 bits of the sum of all the pixel values constituting one frame are used as a reference value. However, the reference value is not limited to this, and any reference value can be used as long as it is a guide for detecting a change in an image. A value derived by another algorithm may be used. In addition, when there is a margin in the processing capability of the change detection unit 35, it is possible to directly compare all pixel values between different frames without using the reference value.

  In the above embodiment, an example in which the light source devices 11R, 11G, 11B and the like operate using a commercial power source as a power source has been described. In this case, the battery life can be extended by reducing the power consumption in the energy saving mode.

  In the above embodiment, the change detection unit 35 calculates a reference value based on all pixel values constituting one frame, and compares the reference value between different frames. It may be divided into regions, and the reference value may be calculated and compared for each region. In this case, calculation and comparison of reference values can be processed in parallel, and the presence / absence of image change can be detected in a short time.

  In the above embodiment, the light modulation devices 14, 14R, 14G, and 14B are provided with a transmissive liquid crystal panel. However, a reflective light modulation device with a reflective liquid crystal panel or the like may be used. Is possible. In addition, a minute mirror array device that modulates light emitted from the light source devices 11R, 11G, and 11B can be used by controlling the emission direction of incident light for each micromirror as a pixel.

  DESCRIPTION OF SYMBOLS 1 ... Projector, 10 ... Image projection part, 11R, 11G, 11B ... Light source device, 12R, 12G, 12B, 12 ... Diffusing element, 13R, 13G, 13B, 13 ... Field lens, 14R, 14G, 14B, 14 ... Light Modulator, 15 ... cross dichroic prism, 16 ... projection lens, 17 ... reflection mirror, 18 ... first dichroic mirror, 19 ... second dichroic mirror, 20a, 20b, 20c ... light emitting element, 30 ... control unit, 31 DESCRIPTION OF SYMBOLS ... Memory | storage part, 32 ... Input operation part, 33 ... Image information input part, 34 ... Image processing part, 35 ... Change detection part, 36 ... Drive circuit, 37 ... Modulation drive part, 38 ... Light source drive part, 38a ... 1st Light source drive unit, 38b ... second light source drive unit, 39 ... power supply circuit, 40 ... power supply control unit, SC ... screen.

Claims (11)

An image information input unit for inputting image information;
A light source device for emitting light;
A light modulation device that modulates light emitted from the light source device based on the image information to form an image;
A projection optical system for projecting the image formed by the light modulation device;
A detection unit that detects the presence or absence of a change in the image based on the image information;
A control unit that switches the lighting state of the light source device to a state of low power consumption when the detection unit detects that the image has not changed;
A projector characterized by comprising: The projector according to claim 1,
The projector is characterized in that a reference value based on the image information is calculated at intervals, and the presence or absence of a change in the image is detected based on a comparison result of the reference value. The projector according to claim 2,
The detection unit divides the image into a plurality of regions, and calculates the reference value for each region. The projector according to any one of claims 1 to 3,
The control unit turns off the light source device when the detection unit detects that the image has not changed. The projector according to any one of claims 1 to 3,
The said control part is a projector characterized by reducing the brightness of the said light source device, when the said detection part detects that the said image is not changing. The projector according to any one of claims 1 to 3,
The control unit causes the light source device to blink when the detection unit detects that the image has not changed. The projector according to any one of claims 1 to 3,
The light source device includes a plurality of light emitting elements,
The control unit turns off a part of the plurality of light emitting elements when the detection unit detects that the image has not changed. The projector according to any one of claims 1 to 3,
A light source driving unit for driving the light source device;
The control unit stops power supply to the light source driving unit when the detection unit detects that the image has not changed. The projector according to any one of claims 1 to 8,
The projector is characterized in that the light source device includes a solid light source. The projector according to any one of claims 1 to 9,
The light source device operates using a battery as a power source. A method of controlling a projector that modulates light emitted from a light source device based on input image information to form an image, and projects the formed image,
A detection step of detecting the presence or absence of a change in the image based on the image information;
A light source control step of switching the lighting state of the light source device to a low power consumption state when the detection step detects that the image has not changed;
A projector control method comprising:

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