JP2014066805A - Projector and light emission control method in projector - Google Patents

Abstract

A projector capable of appropriately adjusting the white balance of projection light from a plurality of light sources, and a light emission control method for the projector.
The projector 1 stores the brightness and duty ratio of the laser light sources 42 and 43 in association with each other, and also adjusts the white balance of the modulated light 28 projected from the projection unit 20. The reference brightness common to the plurality of laser light sources 42 and 43 is obtained based on the characteristics of the storage unit 15 storing the light emission amount adjustment value 15b of 43 and any one of the laser light sources 42 and 43, and this reference brightness Further, the light emission amounts of the respective laser light sources 42 and 43 are adjusted based on the duty ratio associated with the brightness to which the gradation value of the modulated light 28 and the adjustment values of the light emission amounts of the respective laser light sources 42 and 43 are applied. And a light emission control unit 18.
[Selection] Figure 1

Description

  The present invention relates to a projector that projects an image on a projection surface using a plurality of light sources, and a light emission control method in the projector.

Conventionally, a projector that modulates light from a light source based on an input image and projects the light onto a screen via a projection lens is known. Also, in projectors, it is known that when the light source is replaced, the white balance changes due to changes in the characteristics of the light source, or the white balance changes due to changes in the light source over time (illuminance). Yes. Therefore, a projector having a function of adjusting the white balance of an image actually projected on a screen to an appropriate state has been proposed (for example, see Patent Document 1).
Conventionally, a projector using a light source such as an LED or a laser that can adjust luminance by PWM (pulse width modulation) control is known (for example, see Patent Document 2).

JP 2006-140839 A JP 2010-051068 A

By the way, in a projector using a light source capable of adjusting the luminance by PWM control, there is a projector that improves the visibility of a projected image by performing intermittent light emission control in which the light source is turned on / off in a short time. . However, when an image is projected on a projection surface using a plurality of light sources, the brightness with respect to the duty ratio of the light sources is not always uniform for each light source. Therefore, it is not easy to appropriately adjust the white balance of the projection light from a plurality of light sources while performing intermittent drive control and PWM control.
SUMMARY An advantage of some aspects of the invention is to provide a projector that can solve the above-described problems of the related art and can appropriately adjust the white balance of projection light from a plurality of light sources, and a light emission control method for the projector.

In order to achieve the above object, the present invention comprises a plurality of light sources and a modulation unit that modulates light emitted from the plurality of light sources, and a projection unit that projects the modulated light modulated by the modulation unit, Storage means for storing the brightness and duty ratio of the light source in association with each other, and storing an adjustment value of the light emission amount of each of the light sources for adjusting the white balance of the modulated light projected from the projection unit, A reference brightness common to the plurality of light sources is obtained based on the characteristics of the light source, and the gradation value of the modulated light and the adjustment value of the light emission amount of each light source are applied to the reference brightness. And a light emission amount adjusting means for adjusting the light emission amount of each of the light sources based on the duty ratio associated with the brightness.
According to the present invention, when adjusting the light emission amounts of a plurality of light sources as a whole, the reference brightness is obtained and controlled based on the characteristics of any one of the light sources, so that the reference brightness is set to an appropriate brightness. By doing so, the light emission amounts of all the light sources can be set to light emission amounts suitable for white balance adjustment. Thereby, white balance can be adjusted appropriately and a high-definition image can be projected.

In the projector according to the aspect of the invention described above, the light emission amount adjusting unit may determine a reference brightness common to the plurality of light sources based on characteristics of the light source having a low light emission amount.
According to the present invention, when a plurality of light sources are caused to emit light intermittently, the reference brightness corresponding to the duty ratio of intermittent light emission is obtained based on the light source with the lowest light emission amount. Is kept within the adjustable range. For this reason, the white balance can be reliably maintained in an appropriate state.

Further, the present invention is the projector described above, wherein the light emission amount adjusting unit performs control for causing the light source to intermittently emit light at a specified duty ratio, and control for adjusting brightness of the light source by PWM control. Thus, the light emission amount of the light source is adjusted.
According to the present invention, when adjusting the light emission amount of the light source by combining intermittent control and PWM control, the white balance can be adjusted appropriately.

The present invention is the projector described above, wherein the light emission amount adjusting unit applies the gradation value of the modulated light and the adjustment value of the light emission amount of each light source to a reference brightness. A duty ratio of PWM control of each of the light sources is obtained based on the duty ratio associated with the above, and light emission of the light sources is controlled.
According to the present invention, the amount of light emitted from each light source can be easily adjusted by PWM control while keeping the white balance in an appropriate state.

According to another aspect of the invention, the projector includes a color light conversion unit that generates a plurality of color lights from the light of any one of the light sources by color conversion and / or spectroscopy.
According to the present invention, white balance can be appropriately adjusted in a configuration in which a plurality of color lights are generated from a single light source by color conversion or spectroscopy.

According to another aspect of the invention, there is provided a light emission control method for a projector including a plurality of light sources, a modulation unit that modulates light emitted from the plurality of light sources, and a projection unit that projects the modulated light modulated by the modulation unit. The brightness and duty ratio of the light source are stored in the storage means in association with each other, and the light emission amount of each light source for adjusting the white balance of the modulated light projected from the projection unit to the storage means An adjustment value is stored, a reference brightness common to the plurality of light sources is obtained based on characteristics of any one of the light sources, and the gradation value of the modulated light and the light emission of each of the light sources are calculated based on the reference brightness. The light emission amount of each light source is adjusted based on the duty ratio associated with the brightness to which the amount adjustment value is applied.
According to the present invention, when adjusting the light emission amounts of a plurality of light sources as a whole, the reference brightness is obtained and controlled based on the characteristics of any one of the light sources, so that the reference brightness is set to an appropriate brightness. By doing so, the light emission amounts of all the light sources can be set to light emission amounts suitable for white balance adjustment. Thereby, white balance can be adjusted appropriately and a high-definition image can be projected.

  According to the present invention, since the light emission amount of the light source of the projector is controlled by obtaining the reference brightness based on the characteristics of any one of the light sources, the light emission amounts of all the light sources are light emission suitable for white balance adjustment. The white balance of the projection light from a plurality of light sources can be adjusted appropriately.

It is a functional block diagram of a projector. It is a figure which shows an example of the relationship between the brightness of a laser light source, and a duty ratio. It is a graph which shows the example of a PWM signal, an intermittent light emission signal, and a pulse signal. It is a flowchart which shows operation | movement of the control part at the time of changing the gradation value of modulated light.

Embodiments to which the present invention is applied will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating a functional configuration of a projector 1 according to the embodiment. A projector 1 as a display device that projects an image onto a screen SC (projection surface) is connected to an external image supply device (not shown) such as a computer such as a PC or various image players via an I / F (interface) 11. An image based on the digital image data connected and input to the interface 11 is projected onto the screen SC.

The projector 1 includes a projection unit 20 that forms an optical image, and an image processing system that electrically processes an image signal input to the projection unit 20. These units are controlled by the control unit 10. Operate.
The projection unit 20 includes a light source unit 21, a light modulation device (modulation unit) 22, and a projection optical system 23. The light source unit 21 includes a light source capable of PWM control of luminance by a pulse signal such as an LED or a laser light source. In the present embodiment, a configuration including laser light sources 42 and 43 using two blue semiconductor laser elements that emit blue laser light is illustrated. The laser light sources 42 and 43 may include a plurality of semiconductor elements and emit a plurality of laser beams. In addition, the projector 1 performs PWM control of the laser light sources 42 and 43 to adjust the amount of light that darkens the brightness of the laser light sources 42 and 43 when the screen SC is dark, and the brightness of the laser light sources 42 and 43 when the screen SC is bright. By adjusting the amount of light to brighten the light, it has a function of improving the dynamic contrast. In addition, the projector 1 performs intermittent light emission that changes the turning on / off of the laser light sources 42 and 43 in a short time, thereby improving the visibility of moving images when projecting 2D images and reducing crosstalk when projecting 3D images. It has a function to make it.

  The light modulation device 22 receives a signal from an image processing system, which will be described later, and modulates the light emitted from the light source unit 21. Modulated light (image light) 23 a, 23 b, 23 c modulated by the light modulation device 22 is guided to the projection optical system 23. As a specific configuration of the light modulation device 22, for example, a system using three transmissive or reflective liquid crystal light valves corresponding to each color of RGB can be cited. In the present embodiment, three transmissive liquid crystal panels corresponding to three color lights of RGB, that is, a liquid crystal panel 22a that modulates blue light B, a liquid crystal panel 22b that modulates red light R, and green light G. The liquid crystal panel 22c to be modulated is provided. The liquid crystal panels 22a, 22b, and 22c included in the light modulation device 22 are driven by a liquid crystal panel driver 33, which will be described later, and change the light transmittance of each pixel arranged in a matrix on each liquid crystal panel, thereby changing the image. Form.

The RGB color lights modulated by the light modulator 22 are combined by a cross dichroic prism (not shown) and guided to the projection optical system 23.
Although not shown, the projection optical system 23 includes a projection lens that is a lens group for projecting the modulated light 23a, 23b, and 23c modulated by the light modulation device 22 onto the screen SC to form an image, and a projection lens. Various mechanisms for changing the state of the projection optical system 23 such as the aperture state, zoom state, and shift position are provided. The projection optical system 23 is connected to a projection optical system drive unit (optical system adjustment means) 34 that controls and drives a mechanism that changes the state of the projection optical system 23.

  The light source unit 21 is connected to a pulse output unit 52 that outputs pulse signals P2 and P3 for controlling light emission of the laser light sources 42 and 43. The pulse output unit 52 includes a PWM signal generation unit 50 and an intermittent light emission signal generation unit 51. The projector 1 performs intermittent light emission control and PWM control on the laser light sources 42 and 43, thereby improving video visibility, reducing crosstalk during 3D image projection, and adjusting the brightness of the projected image. Is configured to be realized.

The pulse output unit 52 generates and outputs pulse signals P2 and P3 based on the control signal P1 input from the control unit 10.
FIG. 2 is a diagram illustrating an example of the relationship between the brightness of the laser light sources 42 and 43 and the duty ratio.
As shown in FIG. 2, the pulse output unit 52 combines the PWM signal generated by the PWM signal generation unit 50 and the intermittent light emission signal generated by the intermittent light emission signal generation unit 51. For example, in the final waveform of the pulse signals P2 and P3 obtained by synthesizing the intermittent light emission signal with the intermittent light emission duty ratio of 60% and the PWM signal with the PWM duty ratio of 25%, the 60% laser light sources 42 and 43 At the time of lighting, PWM waveform driving with a duty ratio of 25% is further performed. That is, the final total duty ratio of the laser light sources 42 and 43 in which the intermittent light emission signal with the duty ratio of 60% and the PWM signal with the duty ratio of 25% is synthesized is 60% × 25% = 15%. 42 and 43 emit light with a light emission amount of 15% of the light emission amount at the maximum output.

  The light source unit 21 includes a laser light source driver (light source driving unit) 40 to which the pulse signal P2 is input from the pulse output unit 52, and a laser light source driver (light source driving unit) 41 to which the pulse signal P3 is input from the pulse output unit 52. It has. The laser light source driver 40 supplies power to the laser light source 42 according to the pulse signal P2, and causes the laser light source 42 to emit light by the power supply. The laser light source driver 41 supplies power to the laser light source 43 according to the pulse signal P3, and causes the laser light source 43 to emit light by the power.

  The laser light source 42 is driven by a laser light source driver 40 to emit blue laser light 42 a, and the blue laser light 42 a is diffused through a diffusion plate 44. The diffused laser light enters the liquid crystal panel 22a of the light modulation device 22 as blue light 20a and is modulated by the liquid crystal panel 22a. On the other hand, the laser light source 43 is driven by a laser light source driver 41 and emits blue laser light in the same manner as the laser light source 42. The blue laser light emitted from the laser light source 43 strikes the phosphor of the phosphor wheel 45 and is converted into yellow light 45 a and enters the spectroscopic unit 46. The spectroscopic unit 46 separates the yellow light 45a by the wavelength component, and the separated red light 20b and green light 20c enter the liquid crystal panel 22b and the liquid crystal panel 22c, respectively. That is, the phosphor wheel 45 and the spectroscopic unit 46 have a function as color light modulation means for generating a plurality of color lights from the light emitted from the laser light source 43 in the light source unit 21.

The pulse output unit 52 turns on the laser light sources 42 and 43 by performing PWM control and intermittent light emission control on the laser light sources 42 and 43 in accordance with the control signal P1 input from the control unit 10, and the laser light source 42. , 43 has a function of adjusting the luminance to a desired luminance. The pulse output unit 52 generates pulse signals P2 and P3 that specify a pulse frequency and a pulse width (on period) in accordance with a control signal P1 input from the control unit 10, and a light source unit through a limiter (not shown). To 21.
The laser light source drivers 40 and 41 turn on the laser light sources 42 and 43 when the pulses of the pulse signals P2 and P3 rise on, and turn off the laser light sources 42 and 43 when the pulse falls off.

Further, the projector 1 is connected to a video input unit 12 having an interface 11 and a conversion processing unit 13 that executes a scaling process of image data input to the video input unit 12. The conversion processing unit 13 executes a conversion process for the resolution of the image data and outputs the processed image data to the control unit 10. The image data input to the projector 1 may be moving image (video) data, but may be still image data.
Here, the interface 11 includes, for example, a DVI (Digital Visual Interface) interface to which a digital video signal is input, a USB interface and a LAN interface, an S video terminal to which a composite video signal such as NTSC, PAL, and SECAM is input, and a composite An RCA terminal to which video signals are input, a D terminal to which component video signals are input, an HDMI connector that conforms to the HDMI (registered trademark) standard, etc., that conforms to the DisplayPort (trademark) standard formulated by VESA (Video Electronics Standards Association) Has connectors and so on. Further, the video input unit 12 may include an A / D conversion circuit that converts an analog video signal into digital image data when an analog video signal is input to the interface 11. The interface 11 may be provided with a wireless communication interface.

The image processing system of the projector 1 is configured around a control unit 10 that controls the entire projector 1 in an integrated manner. The projector 1 also includes a storage unit 15, an input processing unit 16, an image processing unit 31, and a liquid crystal panel driver 33. The storage unit 15 stores data processed by the control unit 10 and a control program executed by the control unit 10. The input processing unit 16 detects a user operation by a remote controller (not shown) or an operation panel. The image processing unit 31 processes the image data and develops the image signal in the frame memory 32. The liquid crystal panel driver 33 performs drawing by driving the liquid crystal panels 22a, 22b, and 22c of the light modulation device 22 based on the image signal output from the image processing unit 31.
The control unit 10 controls each unit of the projector 1 by reading and executing the control program stored in the storage unit 15. The control unit 10 detects the content of the operation performed by the user based on the operation information input from the input processing unit 16, and according to this operation, the image processing unit 31, the liquid crystal panel driver 33, the projection optical system drive unit 34 and the pulse output unit 52 are controlled to project an image on the screen SC.

  The input processing unit 16 receives and decodes a radio signal transmitted from a remote controller (not shown) for operating the projector 1 and detects an operation on the remote controller, and a button operation on an operation panel (not shown) of the projector 1. It has a function to detect. The input processing unit 16 generates an operation signal indicating an operation on the remote controller or the operation panel and outputs the operation signal to the control unit 10. Further, the input processing unit 16 controls the lighting state of the indicator lamp of the operation panel (not shown) according to the operation state and setting state of the projector 1 according to the control of the control unit 10.

  The image processing unit 31 acquires the image data output from the conversion processing unit 13 according to the control of the control unit 10, and determines the image size or resolution, whether the image is a still image or a moving image, and the frame rate in the case of a moving image. The attribute of the image data such as, and the gradation value of the image data are determined. The image processing unit 31 develops an image in the frame memory 32 for each frame. The image processing unit 31 performs resolution conversion processing when the resolution of the acquired image data is different from the display resolution of the liquid crystal panel of the light modulation device 22, and when zooming is instructed by operation of the remote control or the operation panel. Performs enlargement / reduction processing and develops the processed image in the frame memory 32. Thereafter, the image processing unit 31 outputs an image for each frame developed in the frame memory 32 to the liquid crystal panel driver 33 as a display signal.

The control unit 10 executes functions of the projection control unit 17, the light emission control unit (light emission amount adjusting unit) 18, the correction control unit 19, and the adjustment value acquisition unit 38 by executing the control program stored in the storage unit 15. Is realized.
The projection control unit 17 initializes each unit of the projector 1 according to the operation detected by the input processing unit 16 and controls the pulse output unit 52 to turn on the laser light sources 42 and 43, and thereby the image processing unit 31 and the liquid crystal panel. The driver 33 is controlled to cause the liquid crystal panels 22a, 22b, and 22c to draw images and project the images. Further, the projection control unit 17 controls the projection optical system driving unit 34 to change the state of the projection optical system 23. The projection optical system driving unit 34 controls the aperture state, lens shift position, and zoom state of the projection optical system 23. The projection control unit 17 may further control the state of a cinema filter or an anamorphic lens (not shown) existing on the optical path, or the state of an illumination stop that adjusts the amount of light irradiated to the liquid crystal panel.

  The light emission control unit (control unit) 18 generates a control signal P1 when starting projection and during projection, and outputs the control signal P1 to the pulse output unit 52. The control signal P1 includes a pulse width, a pulse period, or a period in which the pulse width of the PWM signal input to the laser light source drivers 40, 41 is turned off, a pulse width, a pulse period, or a period in which the pulse of the intermittent emission signal is turned off, Is specified. The light emission control unit 18 adjusts the light emission amounts of the laser light sources 42 and 43 by changing the pulse width of the PWM signal and the intermittent light emission signal and the pulse period or the period during which the pulse is turned off.

The correction control unit 19 calculates the tilt (projection angle) of the screen SC with respect to the projector 1 and the projection distance to the screen SC, and executes correction processing such as trapezoidal distortion correction. The correction control unit 19 controls the image processing unit 31 based on the calculated projection angle and projection distance, and corrects the distortion of the projection image on the screen SC by deforming the image developed in the frame memory 32. Display a good rectangular image. The correction control unit 19 calculates a projection angle and a projection distance to detect a disorder of the projected image on the screen SC, or when a correction execution is instructed by an operation of an operation panel (not shown). Are newly calculated, and a process of correcting the projection image according to the calculated parameters is executed.
The modulated light 28 is a combined light obtained by combining the blue light 20a, the red light 20b, and the green light 20c emitted from the laser light sources 42 and 43 by the projection optical system 23.

  The projector 1 emits color light of three colors (three primary colors) of red (R), green (G), and blue (B) by two laser light sources 42 and 43, and these color lights are liquid crystal panels 22a, 22b, and 22c. Then, the light is transmitted or reflected and synthesized by a projection optical system 23 using a prism or the like to generate modulated light 28, and the magnification and focus are adjusted by a lens and projected onto the screen SC. For this reason, the blue laser light 42a emitted from the laser light source 42 becomes the blue light 20a. However, the blue laser light 43a emitted from the laser light source 43 is converted into yellow light 45a, and then is split into red light 20b and green light 20c. Is done.

  The ratio of the amount of light of the blue light 20a, red light 20b, and green light 20c is determined by the output of the laser light sources 42 and 43, the conversion efficiency for converting the blue laser light 43a into yellow light 45a by the phosphor wheel 45, and the diffusion plate 44 It may be influenced by various conditions such as the diffusion state, the spectral characteristics of the spectroscopic unit 46, and the states of the liquid crystal panels 22a, 22b, and 22c. In consideration of such influence, the projector 1 is adjusted in white balance so that accurate white color can be reproduced.

Further, the projector 1 calculates the gradation value (brightness) of the modulated light 28 that is a combination of the blue light 20a, the red light 20b, and the green light 20c emitted from the laser light sources 42 and 43, based on the gradation value of the image data. It is configured so that it can be changed.
However, in the projector 1 that synthesizes and projects the light emitted by the two laser light sources 42 and 43, the brightness efficiency with respect to the duty ratio of the laser light sources 42 and 43 is different for each laser light source 42 and 43 due to the various conditions described above. Different. Therefore, when PWM control is performed while the laser light sources 42 and 43 are intermittently emitted, and the gradation value of the modulated light 28 is changed based on the gradation value of the image data, the duty ratio of the laser light sources 42 and 43 to the duty ratio is changed. Due to the difference in brightness efficiency, the white balance of the projected image projected on the screen SC is disturbed, and accurate white cannot be reproduced.

Thus, in order to properly adjust the white balance that is disturbed by the difference in brightness efficiency with respect to the duty ratio of the laser light sources 42 and 43, the storage unit 15 of the projector 1 includes the duty ratios of the laser light sources 42 and 43, and A duty / brightness table 15a in which the brightness efficiencies of the laser light sources 42 and 43 are associated with each other is stored in advance.
FIG. 3 is a chart illustrating examples of the PWM signal, the intermittent light emission signal, and the pulse signal.
In the duty / brightness table 15a, as illustrated in FIG. 3, the duty ratio of the laser light sources 42 and 43 and the brightness efficiency of the laser light sources 42 and 43 are stored in association with each other. For example, as shown in FIG. 3, the duty / brightness table 15a may be a graph in which the horizontal axis represents the duty ratio of the laser light sources 42 and 43 and the vertical axis represents the brightness efficiency of the laser light sources 42 and 43. good. For example, when the horizontal axis is considered as the duty ratio of intermittent light emission of the laser light sources 42 and 43, the laser light sources 42 and 43 increase in efficiency when the duty ratio of intermittent light emission is lowered, and can obtain brightness with less force. Can be read from FIG.

Further, as can be read from the duty / brightness table 15 a, it can be seen that the efficiency of the laser light source 42 is better than the efficiency of the laser light source 43. This is because the light emitted from the laser light source 43 is affected by the spectral filter included in the phosphor wheel 45 and the spectroscopic unit 46, and the duty / brightness table 15a includes the duty ratio of the laser light sources 42 and 43 and the laser. The relationship with the brightness efficiency of the light sources 42 and 43 is set in advance in consideration of various influences. It should be noted that the duty / brightness table 15a may be a standard table showing the relationship between the duty ratio of the laser light sources 42 and 43 and the brightness efficiency of the laser light sources 42 and 43, or alternatively, In consideration of the influence of 43 individual differences, the projector 1 may be created based on the measurement value when each projector 1 is manufactured.
The brightness of the laser light sources 42 and 43 is 100% when the duty ratio of intermittent light emission is 100%, and the brightness when the duty ratio of intermittent light emission is changed is the duty ratio of intermittent light emission. This indicates how much the brightness is relative to the brightness when the ratio is 100%. For this reason, the brightness in the table is not the brightness that is quantitatively indicated by the output values, light emission amounts, or light fluxes of the laser light sources 42 and 43.

  Further, the storage unit 15 of the projector 1 stores an adjustment value 15 b of the light emission amount of each of the laser light sources 42 and 43 for adjusting the white balance of the modulated light 28. Although not shown, the adjustment value 15b is set based on the outputs of the laser light sources 42 and 43 when white (all white) is projected with the white balance of the modulated light 28 adjusted. More specifically, a ratio of what percentage of other light source emits light with respect to a light source that emits 100% of light when projecting all white is stored in the storage unit 15 as an adjustment value 15b. Remembered. For example, when the output of the laser light source 43 is 100% and the output of the laser light source 42 is 90% when all white is projected, the light emission of each of the laser light sources 42 and 43 for adjusting the white balance. The amount adjustment value 15b is set as laser light source 42: laser light source 43 = 90: 100 and is stored in the storage unit 15.

Next, the operation of the control unit 10 when appropriately adjusting the white balance of the modulated light 28 while changing the gradation value of the modulated light 28 based on the gradation value of the image data will be described with reference to the flowchart of FIG. explain.
The control unit 10 uses a plurality of laser light sources 42 based on the light emission amount of the laser light source emitting 100% of the laser light sources 42 and 43 when 100% white (all white) is projected. , 43 is adjusted. That is, the control unit 10 changes the light emission amounts of the plurality of laser light sources 42 and 43 with reference to the laser light source with the lowest light emission amount among the laser light sources 42 and 43. Note that the laser light source with the lowest light emission amount is the laser light source with the lowest light emission amount with respect to the duty ratio of intermittent light emission when all white is projected. By adjusting the light emission amount of the plurality of laser light sources 42 and 43 based on the characteristics of the light source having a low light emission amount with respect to the duty ratio of intermittent light emission, the laser light source 42 and the laser light source 42 at all duty ratios for all the laser light sources 42 and 43, The amount of emitted light 43 can be kept within a range in which the white balance can be adjusted.

  In the present embodiment, the adjustment value 15b of the light emission amount of each of the laser light sources 42 and 43 for adjusting the white balance is laser light source 42: laser light source 43 = 90: 100, and an output is obtained when all white is projected. A case where white balance is maintained in an appropriate state with reference to 100% laser light source 43 will be described as an example. The white balance can be adjusted not only when all white (tone value 100%) is projected, but also when an image with a tone value of 50% or 40% is projected. Further, the output ratio between the laser light source 42 and the laser light source 43 when all white is projected is the difference in output due to the individual difference between the laser light sources 42 and 43, and the blue laser light 43a is converted into yellow light 45a by the phosphor wheel 45. A standard ratio set in advance based on various conditions such as conversion efficiency for conversion, diffusion state in the diffusion plate 44, spectral characteristics of the spectral unit 46, and states of the liquid crystal panels 22a, 22b, and 22c is stored in the storage unit 15 in advance. It may be configured to store, or may be configured to store in advance in the storage unit 15 based on a value detected using an external light amount sensor in the manufacturing process of the projector 1.

  Then, the control unit 10 uses the laser light source 43 whose output is 100% when all white is projected as a reference, the gradation value of the image data, the duty / brightness table 15a stored in the storage unit 15 in advance, Based on the above, the PWM control duty ratio of the laser light sources 42 and 43 that can maintain the white balance in an appropriate state is calculated. Note that the duty ratio of intermittent light emission is uniquely determined with respect to the frequency of the video input signal, and in this embodiment, the case where the duty ratio of intermittent light emission is defined as 60% will be described as an example. To do.

First, the image processing unit 31 determines the gradation value of the image data and inputs it to the control unit 10 (step S1). In the present embodiment, a case where the gradation value of image data is 50% will be described as an example.
Subsequently, the control unit 10 obtains a reference brightness common to all the laser light sources 42 and 43 from the duty / brightness table 15a stored in advance in the storage unit 15 (step S2). The reference brightness common to all the laser light sources 42 and 43 is obtained based on the brightness of the laser light source 43 whose output is 100% when all white is projected, and when the duty ratio of intermittent light emission is 60%. It is calculated based on the brightness of the laser light source 43. From the duty / brightness table 15a shown in FIG. 3, the reference brightness common to all the laser light sources 42 and 43 when the duty ratio of intermittent light emission is 60% is obtained when the duty ratio of intermittent light emission is 100%. It is required to be 70% of the brightness. That is, 100% brightness of the laser light source 43 when the duty ratio of intermittent light emission is 60% is calculated to be 70% of the brightness when the duty ratio of intermittent light emission is 100%. This brightness is 70%. Is the standard brightness.

  Subsequently, the control unit 10 uses the function of the light emission control unit 18 to adjust the gradation value of the image data and the light emission amounts of the laser light sources 42 and 43 stored in the storage unit 15 to the reference brightness. The brightness of one of the laser light sources 42 and 43 to which the adjustment value is applied is calculated (step S3). The brightness of the laser light source 43 obtained by applying the gradation value of the image data and the adjustment value for adjusting the light emission amount of the laser light source 43 stored in the storage unit 15 to the reference brightness is 70% × 50% ×. 100% = 35% brightness is calculated. Further, the brightness of the laser light source 42 obtained by applying the gradation value of the image data and the adjustment value for adjusting the light emission amount of the laser light source 42 stored in the storage unit 15 to the reference brightness is 70% × 50. It is calculated that the brightness is% × 90% = 31.5%.

  Next, the control unit 10 obtains, from the duty / brightness table 15a, the final total duty ratio associated with the brightness of the laser light sources 42 and 43 calculated in step S3 by the function of the light emission control unit 18 ( Step S4). The final total duty ratio at which the brightness of the laser light source 43 becomes 35% is obtained as 20% from the duty / brightness table 15a. The final total duty ratio at which the brightness of the laser light source 42 is 31.5% is obtained as 15% from the duty / brightness table 15a.

  Next, the control unit 10 uses the function of the light emission control unit 18, based on the final total duty ratio of each laser light source 42, 43 obtained in step S4 and the duty ratio of intermittent light emission, The duty ratio of PWM control 43 is calculated (step S5). The duty ratio of PWM control at which the final total duty ratio of the laser light source 43 is 20% is calculated as 20% ÷ 60% = 33%. Further, the duty ratio of the PWM control in which the final total duty ratio of the laser light source 42 is 15% is calculated as 15% ÷ 60% = 25%.

The control unit 10 determines whether or not the PWM control duty ratio has been calculated for all of the plurality of laser light sources 42 and 43 (step S6), and if there is a laser light source for which the PWM control duty ratio has not yet been calculated. When the determination is made (step S6: No), the flow of steps S3 to S6 is repeated until the duty ratio of the PWM control is calculated for all the laser light sources 42 and 43. When it is determined that the duty ratio of the PWM control is calculated for all of the plurality of laser light sources 42 and 43 (step S6: Yes), the control unit 10 uses the function of the light emission control unit 18 to each of the laser light sources 42 and 43. , A control signal P1 is generated based on the defined duty ratio of intermittent light emission and the calculated duty ratio of PWM control, and is output to the pulse output unit 52.
The pulse output unit 52 generates pulse signals P2 and P3 based on the input control signal P1 and outputs them to the laser light source drivers 40 and 41, respectively. Thereby, the light emission amounts of the plurality of laser light sources 42 and 43 can be adjusted as a whole based on the gradation value of the image data.

  According to these configurations, it is possible to provide the projector 1 that can maintain white balance in an appropriate state while performing intermittent light emission control and PWM control for the plurality of laser light sources 42 and 43. Therefore, it is possible to reduce the crosstalk at the time of projecting the 3D image and to improve the visibility of the moving image at the time of projecting the 2D image, which is a feature of the intermittent light emission control, and keep the white balance in an appropriate state. It is possible to provide the projector 1 that can change the brightness of the projected image based on the image data. In addition, according to these configurations, since the amount of light emitted from each of the plurality of laser light sources 42 and 43 is adjusted based on the brightness of the laser light source that outputs 100% when all white is projected, all the laser light sources The light emission amounts of 42 and 43 can be kept within a range in which the white balance can be adjusted, and the white balance can be surely kept in an appropriate state.

  As described above, according to the projector 1 according to the embodiment to which the present invention is applied, the plurality of laser light sources 42 and 43 and the light modulation device 22 that modulates the light emitted from the plurality of laser light sources 42 and 43 are provided. The projection unit 20 that projects the modulated light modulated by the light modulation device 22 and the brightness and the duty ratio of the laser light sources 42 and 43 are stored in association with each other, and the modulated light 28 projected from the projection unit 20 Common to a plurality of laser light sources 42 and 43 based on the characteristics of one of the laser light sources 42 and 43 and the storage unit 15 that stores the adjustment value 15b of the light emission amount of each laser light source 42 and 43 for adjusting the white balance The reference brightness is obtained, and the brightness obtained by applying the gradation value of the modulated light 28 and the adjustment value of the light emission amount of each of the laser light sources 42 and 43 to the reference brightness. And a light emission control unit 18 for adjusting the light emission amount of each of the laser light sources 42 and 43 based on the continuous Tagged duty ratio. According to this configuration, when overall light emission amounts of the plurality of laser light sources 42 and 43 are adjusted based on the gradation value of the image data, the reference brightness is determined based on the characteristics of one of the laser light sources 42 and 43. Control for the best. Thus, by setting the reference brightness to an appropriate brightness, the light emission amounts of all the light sources can be set to light emission amounts suitable for white balance adjustment. Thereby, white balance can be adjusted appropriately and a high-definition image can be projected.

  In addition, the light emission control unit 18 of the projector 1 obtains a reference brightness common to the plurality of laser light sources 42 and 43 based on the characteristics of the laser light source 43 having the lower light emission amount among the laser light sources 42 and 43. According to this configuration, when the plurality of laser light sources 42 and 43 are caused to emit light intermittently, the reference brightness corresponding to the duty ratio of the intermittent light emission is obtained based on the characteristics of the laser light source 43 having a low light emission amount. As a result, the light emission amounts of all the laser light sources 42 and 43 are kept within a range in which the white balance can be adjusted. Therefore, the white balance can be reliably maintained in an appropriate state.

  In addition, the light emission control unit 18 of the projector 1 executes a control for causing the laser light source to intermittently emit light according to the designated final total duty ratio, and a control for adjusting the brightness of the light source by PWM control. The light emission amounts of 42 and 43 are adjusted. Thereby, when adjusting the light emission amount of a light source combining intermittent light emission control and PWM control, white balance can be adjusted appropriately.

  Further, the light emission control unit 18 of the projector 1 sets the duty ratio associated with the brightness to which the gradation value of the modulated light 28 and the adjustment value of the light emission amount of each of the laser light sources 42 and 43 are applied to the reference brightness. Based on this, the duty ratio of PWM control of each of the laser light sources 42 and 43 is obtained, and the light emission of the laser light sources 42 and 43 is controlled. Thereby, the light emission amount of each laser light source 42 and 43 can be easily adjusted by PWM control, maintaining a white balance in an appropriate state.

  The projector 1 also includes a spectroscopic unit 46 that generates a plurality of color lights from the light of one of the laser light sources 42 and 43 by color conversion and / or spectroscopy. Thereby, in the structure which produces | generates several color light from one laser light source 43 by color conversion or spectroscopy, white balance can be adjusted appropriately.

Each of the above embodiments is merely an example of a specific aspect to which the present invention is applied, and the present invention is not limited thereto. The present invention can be applied as a different aspect from the above embodiment.
Each functional unit of the projector 1 illustrated in FIG. 1 includes a functional configuration realized by cooperation of hardware and software, and the specific implementation is not particularly limited. In addition, the specific detailed configuration of each part of the projector 1 can be arbitrarily changed without departing from the gist of the present invention.
The projector 1 according to the present embodiment is a liquid crystal projector including a liquid crystal panel 22a that modulates blue light B, a liquid crystal panel 22b that modulates red light R, and a liquid crystal panel 22c that modulates green light G. However, the present invention is not limited to this, and a projector using a digital mirror device (DMD) may be used.

In addition, the projector 1 of the present embodiment is configured to adjust the white balance of the modulated light 28 so that the white balance is accurate. However, the present invention is not limited to this, and the projection screen should be set to a bluish screen or a reddish screen. The color light balance of the modulated light may be set to an arbitrary color.
In addition, the projector 1 according to the present embodiment is configured to include the two laser light sources 42 and 43. However, the projector 1 is not limited thereto, and includes three light sources prepared for each primary color, and includes the phosphor wheel 45 and the spectroscopic unit 46. An omitted configuration may be used.
In the projector 1 according to the present embodiment, the intermittent light emission start timing and the intermittent light emission duty ratio are uniquely determined based on the video input signal. In order to reduce individual differences, the configuration may be arbitrarily changed. Also, for each input signal of the video, a sample video based on the gradation value specified by the user is created, and based on the sample video, the user appropriately starts the intermittent light emission timing or intermittent It is good also as a structure which can set the duty ratio of light emission.

Further, the projector 1 according to the present embodiment is configured to obtain the reference brightness based on the duty ratio of intermittent light emission. However, the present invention is not limited thereto, and is input to the laser light sources 42 and 43 when performing intermittent light emission. A configuration may be adopted in which the current brightness of the power supply is increased to increase the reference brightness itself.
Further, the color for balance adjustment may be changed according to the color mode setting provided in the projector 1. For example, when the color mode setting is dynamic, the balance is adjusted so that the modulated light 28 becomes white as in this embodiment, and when the color mode setting is the cinema mode, the modulated light 28 becomes a bluish color. You may adjust the balance.
Moreover, the structure which can change the start timing of intermittent light emission for every color mode, and the duty ratio of intermittent light emission to the setting suitable for each color mode may be sufficient.
Further, the balance of the modulated light 28 may be adjusted so as to obtain an optimum color according to the projection environment. In this case, the projector 1 includes an illuminance sensor or a camera that measures the ambient light, and the balance of the modulated light 28 may be adjusted so that an appropriate color is obtained according to the measured ambient light.

  DESCRIPTION OF SYMBOLS 1 ... Projector, 10 ... Control part, 12 ... Image | video input part, 15 ... Memory | storage part (memory | storage means), 17 ... Projection control part, 18 ... Light emission control part (light emission amount adjustment means), 20 ... Projection part, 21 ... Light source , 22 ... light modulator (modulation means), 23 ... projection optical system, 28 ... modulated light, 40, 41 ... laser light source driver (light source drive means), 42, 43 ... laser light source (light source), 45 ... phosphor Wheel (color light conversion means), 46 ... spectral part (color light conversion means), 50 ... PWM signal generation part, 51 ... intermittent light emission signal generation part, 52 ... pulse output part, SC ... screen.

Claims (6)

Multiple light sources;
Modulation means for modulating light emitted from the plurality of light sources,
A projection unit that projects the modulated light modulated by the modulation unit;
Storage means for storing the brightness and duty ratio of the light source in association with each other, and storing an adjustment value of the light emission amount of each light source for adjusting the white balance of the modulated light projected from the projection unit,
Based on the characteristics of any one of the light sources, a reference brightness common to the plurality of light sources is obtained, and a gradation value of the modulated light and an adjustment value of the light emission amount of each of the light sources are calculated based on the reference brightness. A projector comprising: a light emission amount adjusting unit that adjusts a light emission amount of each of the light sources based on the duty ratio associated with the applied brightness. The projector according to claim 1,
The projector is characterized in that the light emission amount adjusting means obtains a reference brightness common to the plurality of light sources based on characteristics of the light source having a low light emission amount. The projector according to claim 1 or 2,
The light emission amount adjusting means adjusts the light emission amount of the light source by executing a control for intermittently emitting the light source at a specified duty ratio and a control for adjusting the brightness of the light source by PWM control. Projector. The projector according to claim 3,
The light emission amount adjusting means is configured to apply each gradation value of the modulated light and an adjustment value of the light emission amount of each light source to a reference brightness based on the duty ratio associated with the brightness. A projector characterized by obtaining a duty ratio of PWM control of the light source and controlling light emission of the light source. The projector according to any one of claims 1 to 4,
A projector comprising color light conversion means for generating a plurality of color lights by color conversion and / or spectroscopy from the light of any one of the light sources. Multiple light sources;
Modulation means for modulating light emitted from the plurality of light sources;
A projection unit that projects the modulated light modulated by the modulation unit;
A method for controlling light emission in a projector including:
The brightness of the light source and the duty ratio are associated with each other and stored in the storage unit, and an adjustment value of the light emission amount of each of the light sources for adjusting the white balance of the modulated light projected from the projection unit to the storage unit. Remember,
Based on the characteristics of any one of the light sources, a reference brightness common to the plurality of light sources is obtained, and a gradation value of the modulated light and an adjustment value of the light emission amount of each of the light sources are calculated based on the reference brightness. A light emission control method in a projector, wherein the light emission amount of each light source is adjusted based on the duty ratio associated with applied brightness.

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