JP2007065012A - Projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type display device that can keep optimum white balance of a display image and obtain high picture quality even if light beams of a plurality of colors of light emitting elements of the plurality of colors vary in quantity owing to deterioration or a fault of the light emitting elements. <P>SOLUTION: The projection type display device is equipped with a light source 10 comprising light emitting elements emitting the color light beams of red, green, and blue, an optical modulating element 14 which uses a liquid crystal device, a projection optical system 16, a detection unit 102 arranged between the optical modulating element 14 and the projection optical system 16 , and a control unit 100. The detection unit 102 detects the quantities of the light beams emitted by those light emitting elements and the control unit 100 keeps white balance of the respective colors by comparing and adjusting the quantities of light of the light emitting elements of respective red, green, and blue, so even if a light emitting is used for a long time to deteriorate and decrease in light quantity, a display image having optimum white balance can be maintained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projection display device, and more particularly to a projection display device that uses a light emitting element to adjust the light amount ratio to a desired white balance.

  A projection display device is known as a display device for enjoying images and images on a large screen. A conventional projection display device separates white light from a light source into red light, green light, and blue light by a color separation means such as a dichroic mirror, and separates the monochromatic light into a light modulation element such as a liquid crystal device or DMD. The mainstream method is to create a color image by color synthesis using color synthesis means such as a cross dichroic prism, and to enlarge and display the image on a screen using a projection optical system such as a projection lens. .

  Conventionally, discharge lamps such as high-pressure mercury lamps and metal halide lamps have been used as light sources. However, in recent years, use of semiconductor light-emitting elements such as LEDs and semiconductor lasers as light sources has been proposed and put into practical use.

  These light-emitting elements do not contain components of heat rays or ultraviolet rays, have advantages such as simple lighting control, high response speed, no fear of rupture, and long life compared to discharge lamps. In addition, the light emitting element is capable of emitting light of three primary colors that produce red, green, and blue color images, and is therefore suitable as a light source for a projection display device, including that there is no need for color separation. .

  The light emitting element is mechanically and electrically connected and mounted on a substrate or a lead frame by silver paste, bonding wire, stud bump, or the like, and is sealed and protected with a sealing material such as epoxy resin or silicon gel. In addition, since this encapsulant has a refractive index of around 1.5, by inserting a light emitting element in the encapsulant, total reflection of light emitted from the light emitting layer at the light emitting element interface is reduced, There is also an effect of increasing the extraction efficiency.

  However, the light emitting element has a problem that the degree of decrease in the amount of light due to a change with time varies depending on the emission color. In light emitting elements that emit short wavelengths such as the ultraviolet region and blue, the sealing material tends to yellow compared to light emitting elements that emit long wavelengths such as red, and the transmittance decreases due to yellowing. The amount of light coming out decreases. In addition, light emitting materials used for light emitting elements differ depending on the light emission color, and in general, GaN-based compound semiconductors are often used in the ultraviolet to green wavelength region, and AlGaInP based materials called quaternary materials in the yellow to red wavelength region. GaAs-based compound semiconductors are often used. The light emitting element emits a lot of heat together with the light, and when a larger amount of current is supplied to increase the amount of light emission, the temperature becomes higher. Since the luminescent material differs depending on the luminescent color, the progress of deterioration due to long-term use at high temperatures differs depending on the luminescent color. Accordingly, since the degree of decrease in the amount of light due to long-term use differs depending on the luminescent color, it has been difficult to maintain a projection image with a desired white balance for producing the white color necessary for the projection display device for a long period of time.

  FIG. 14 is a schematic configuration diagram showing a configuration of an optical system of a conventional projection display apparatus. In FIG. 14, the same components as those of the embodiment of the present invention will be described using the same reference numerals as those of the embodiment. In FIG. 14, the optical system 55 of the projection display device 5 includes an R (red) color light source 10R, a G (green) color light source 10G, a B (blue) color light source 10B, a color composition unit 11, a polarizing plate 13, and a light modulation element. 14, an analyzer 40, and a projection optical system 16. Each light source 10 and the light modulation element 14 are controlled by the control unit 100. Monochromatic light emitted from the R color light source 10R, the G color light source 10G, and the B color light source 10B using the light emitting elements is synthesized in the same optical path by the color synthesizing unit 11 and enters the polarizing plate 13. Although not shown in the figure, a polarization unifying unit using a polarizing beam splitter array and a λ / 2 phase difference plate may be inserted before the polarizing plate 13. Only linearly polarized light in one direction passes through the polarizing plate 13 and enters the light modulation element 14. In this example, since the optical system uses a single-plate light modulation element, the three primary colors of red, green, and blue are sequentially turned on, and light of each color modulated by the light modulation element 14 is temporally synthesized. Thus, an FSC (Field Sequential Color) display method for obtaining a full color image is adopted. In the light modulation element 14, the polarization direction of the incident linearly polarized light is controlled corresponding to the image to be displayed, and the image is projected onto a screen (not shown) or the like through the analyzer 40 and the projection optical system 16. Since the analyzer 40 has a function of transmitting only one direction of linearly polarized light in the same manner as the polarizing plate, the light of the projection image is polarized by the light modulation element 14 in accordance with the polarization direction of the analyzer 40. It is rotated.

  At this time, in the conventional projection display device, even when the white balance of the projected image is adjusted to the optimum balance for each color at the time of shipment from the factory, the light amount of each light source deteriorates due to long-term use. At this time, the degree of deterioration of the amount of emitted light varies depending on the emission color, and thus has a problem that it is difficult to maintain a desired white balance, and a method for solving this problem is disclosed. (See Patent Documents 1 to 3).

  However, in the display device, the light source device, and the illumination device disclosed in Patent Document 1, since the light amount is measured immediately after the light emitting element or in the middle of the optical system, the light amount due to deterioration of the optical component or the light modulation element after the measurement location is measured. The decrease in the light amount cannot be detected, and the amount of light on the optical path of the actual optical system is not detected.

  Patent Document 2 discloses a laser that demultiplexes an S wave from a laser beam by a polarizing beam splitter, detects a light amount by providing a light receiving element in the optical path, converts the light amount into a voltage, and detects a lifetime compared with a reference voltage. Although a length measuring device is disclosed, output control of laser light is not performed and cannot be used for white balance control.

In Patent Document 3, in a display device using a light emitting element group composed of a plurality of light emitting element arrays, the operation time is stored, and a correction coefficient is obtained in contrast to the stored luminance deterioration curve for each light emitting element. Although a method of displaying an image with constant chromaticity and luminance by adjusting the current value to the light emitting element group is disclosed, the actual light quantity is not measured.
JP 2004-184852 A JP-A-9-72719 JP 2003-202838 A

  As described above, the light source of the projection display device using a single light modulation element that performs color synthesis using a red, green, and blue primary color LED (Light Emitting Diode) or a semiconductor laser. The degree of decrease in light amount due to long-term use varies depending on the emission color. The reason is that the sealing material that seals and protects the light emitting element is discolored by light having a short wavelength in the blue or ultraviolet region, and the transmittance is lowered particularly when used for a long time. This is because the amount of light to be reduced decreases. In addition, since light emitting materials of different compound semiconductors corresponding to the emission wavelength are used, the degree of deterioration of the light emission amount due to long-term use, particularly at high temperatures, differs depending on the light emission color.

  For the above reason, since the rate of change in brightness of the light emitting element over time varies depending on the light emission color, the white balance of the three primary colors of the display image changes, and an image with an optimal white balance cannot be maintained. There was a problem. In addition, a light source using a plurality of light emitting elements has a problem in that the white balance of a display image is changed as described above because the rate of change in brightness differs depending on the individual light emitting elements even in the same light emitting color. It was. These caused the problem that high-quality images could not be obtained over time, but there is no method for controlling individual light-emitting elements based on the actual amount of light for each color projected on the display surface in the prior art. It was.

  It is an object of the present invention to maintain an optimum white balance of a display image even when the light amount of each color in a light emitting element of a plurality of colors changes due to deterioration or failure of the light emitting element, so that high quality image quality can be obtained. To provide a mold display device.

The projection display device of the present invention is
A light source unit, a linear polarization unit that converts light from the light source unit into linearly polarized light, a light modulation element that modulates light from the linear polarization unit, and a polarization direction of light from the light modulation unit Polarization separating means for separating the first linearly polarized light and the second linearly polarized light orthogonal to each other and emitting them to different optical paths, and the first linearly polarized light emitted from the polarization separating means are projected. The projection optical system, a light receiving element that detects the amount of received light of the second linearly polarized light emitted from the polarization separation means, a light source unit and a light modulation element are driven, and the light source unit Control means for controlling the light emission state.

  The light source unit may include a red light source that emits red light, a green light source that emits green light, a blue light source that emits blue light, and a color composition unit that synthesizes light from each color light source. Each may have at least one light emitting element, and the light emitting element may be a light emitting diode or a semiconductor laser.

  The light modulation element may be a liquid crystal device. The polarization separation means may have a polarization separation surface made of a dichroic film that transmits the first linearly polarized light and reflects the second linearly polarized light. The light receiving element may be a photodiode or a phototransistor, and may be provided corresponding to each of red, green, and blue colors.

  The control means compares the light amounts of the light emitting elements of red, green, and blue colors from the amount of received light of the second linearly polarized light detected by the light receiving element, and controls the driving conditions of the light source so as to maintain the white balance of each color. May be. A polarizing plate may be disposed between the polarization separating means and the projection optical system.

  Since the light quantity of each color of red light, green light, and blue light is measured by the detection unit, and the drive condition of the light emitting element is changed by the control unit, the light quantity of each color is adjusted to a light quantity ratio that achieves a desired white balance. Even when the light-emitting element deteriorates due to long-term use and the amount of light decreases, it is possible to maintain a display image with an optimal white balance.

Since the present invention is configured so that the intensity of light emitted from each light emitting element can be monitored even if the brightness of each light emitting element changes with temperature or changes over time in each color, Since the driving conditions of red light, green light, and blue light can be changed so as to achieve an optimal white balance, the following effects can be obtained. That is,
1) Even if the brightness of each color light source changes due to individual differences, changes over time, and driving conditions, the white balance and color reproduction range can be maintained.
2) The chromaticity coordinates of white and the chromaticity coordinates of the three primary colors can be matched with a predetermined video standard.
3) The white chromaticity coordinates and the three primary color chromaticity coordinates can be changed according to the video signal.
4) Even if white is adjusted to an arbitrary color, the chromaticity coordinates of white can be known.
5) While maintaining the white balance and color reproduction range, the display image can be brightened or darkened to save power.
6) When the light modulation element is replaced, the VT characteristic which is the voltage (V) -transmittance (T) characteristic of the liquid crystal panel can be measured in the field, and the gradation reproducibility can be corrected. .
7) The failure and life of the light emitting element can be monitored.

  A projection display device according to the present invention includes a light source including a light emitting element that emits red, green, or blue light, a light modulation element using a liquid crystal device, a projection optical system, and a light modulation element between the light modulation element and the projection optical system. It has a detection unit and a control unit, and the detection unit measures the amount of light emitted from those light emitting elements, and the control unit compares and adjusts the amount of light emitted from each of the red, green, and blue light emitting elements. Thus, the white balance of each color is maintained, so that it is possible to maintain a display image with an optimal white balance even if the light emitting element deteriorates due to long-term use and the light quantity decreases. Here, the white balance means a ratio (balance) of light amounts of light emitting elements of red, green, and blue for displaying white.

  Next, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a projection display apparatus according to a first embodiment of the present invention. Here, the description of the configuration of the projection display apparatus not directly related to the present invention is omitted. The projection display apparatus 1 of the present invention includes an optical system 51 and a control unit 100, and the optical system 51 includes an R color (red) light source 10R, a G color (green) light source 10G, and a B color (blue) light source 10B. The light combining unit 11 includes a light source unit 101, an illumination optical system 12, a polarizing plate 13, a light modulation element 14, a detection unit 102, and a projection optical system 16. The detection unit 102 includes a polarization separation unit 15 and a light receiving element 17. Composed. In addition, a polarizing plate that transmits only P-polarized light may be disposed on the exit surface 21 of the polarization separating unit 15 in order to improve the contrast of the projected image.

  As the R color light source 10R, the G color light source 10G, and the B color light source 10B, light emitting elements that emit monochromatic light are used. In FIG. 1, only one light emitting element is used for each color. Any number of can be used. In the subsequent stage of the light sources 10R, 10G, and 10B for each color, a color synthesizing unit 11 and an illumination optical system 12 that synthesize the R, G, and B light paths into one are arranged. A polarizing plate 13 is disposed on the incident side of the light modulation element 14, and a polarization separation unit 15 is disposed on the emission side. A single liquid crystal device is used for the light modulation element 14. A polarization beam splitter or the like is used as the polarization separation means 15, which has a polarization separation surface 30 made of a dichroic film inclined by 45 ° with respect to incident light, transmits linearly polarized light in one polarization direction, and the polarization direction is It has the function of reflecting the other orthogonally polarized light that is orthogonal. In FIG. 1, linearly polarized light having a polarization direction parallel to the paper surface (hereinafter referred to as P-polarized light) is transmitted, and linearly polarized light having a polarization direction perpendicular to the paper surface (hereinafter referred to as S-polarized light) is reflected. It has a configuration. As indicated by the broken arrow, the projection optical system 16 is disposed on the optical path of the P-polarized light that is the transmitted light 20A that has passed through the polarization separating means 15, and the light modulated by the light modulation element 14 is illustrated. Project to no screen etc. Further, as indicated by solid arrows, the S-polarized light that is the reflected light 20B reflected by the polarization separation surface 30 of the polarization separation means 15 is incident on the light receiving element 17. As the light receiving element 17, a photodiode, a phototransistor, or the like that converts light intensity into an electrical quantity can be used, and the polarization separating means 15 and the light receiving element 17 have a function as the detection unit 102. The control unit 100 has a function of driving the R color light source 10R, the G color light source 10G, and the B color light source 10B, and a function of controlling the light modulation element 14 and the light receiving element 17.

  As the color display method, an FSC (Field Sequential Color) display method is used. The R color light source 10R, the G color light source 10G, and the B color light source 10B are sequentially turned on, and the light modulation element 14 modulates the light according to the R color video signal, the G color video signal, and the B color video signal, respectively. As a result, R, G, and B color images are sequentially displayed, and are synthesized by the human eye and recognized as a color image.

  Next, the operation of the projection display apparatus 1 according to the first embodiment of the present invention will be described with reference to FIG. In FIG. 1, each light emitted from an R color light source 10 </ b> R, a G color light source 10 </ b> G, and a B color light source 10 </ b> B that emits monochromatic light using a light emitting element is combined into one optical path by a color combining unit 11. A spherical lens or a rod lens for controlling the illumination light may be arranged between each light source 10 and the color synthesizing unit 11 or between the color synthesizing unit 11 and the polarizing plate 13. An LED, a semiconductor laser, or the like can be used as the light emitting element, and a cross dichroic prism, a cross dichroic mirror, or the like is used as the color composition unit 11.

  The light that has passed through the color synthesizing unit 11 passes through the illumination optical system 12 and the polarizing plate 13 to illuminate the light modulation element 14. The illumination optical system 12 has a polarization uniformizing unit composed of a polarization beam splitter array and a λ / 2 wavelength plate, and separates naturally polarized light into two polarization directions whose polarization directions are orthogonal to each other. It has a function to unify linearly polarized light in the direction. In this example, naturally polarized light is separated into S-polarized light and P-polarized light, and only P-polarized light is passed through a λ / 2 wavelength plate to be unified into S-polarized light. A transmissive liquid crystal device is used for the light modulation element 14, and only S-polarized light is incident on the polarizing plate 13.

  When the liquid crystal device of the light modulation element 14 displays a color image, the S-polarized light incident on the light modulation element 14 is rotated by 90 ° in the polarization direction by the light modulation element 14 to become P-polarized light. Is emitted. In this case, white display is performed when the ratio of the light amounts of the R, G, and B colors maintains the white balance and is the maximum light amount. Further, the S-polarized light incident on the light modulation element 14 is emitted from the light modulation element 14 as the S-polarized light without being rotated in the polarization direction by the light modulation element 14, and the light of R color, G color, and B color is emitted. A case where the ratio of the amount of light maintains white balance and is the maximum amount of light is referred to as black display. In white display and black display, the amount of R, G, and B light emitted is controlled by each color light source 10 and the light modulation element 14.

  In the case of performing white display, the S-polarized light incident on the light modulation element 14 is rotated by 90 ° in the polarization direction by the light modulation element 14 as shown in FIG. The light is emitted from the light modulation element 14, is transmitted through the polarization separation surface 30 of the polarization separation means 15, and is projected onto a screen or the like (not shown) by the projection optical system 16. When black display is performed, the S-polarized light incident on the light modulation element 14 remains the S-polarized light without being rotated in the polarization direction, as indicated by the solid arrow reflected light 20B. 14, is reflected by the polarization separation surface 30 of the polarization separation means 15, and enters the light receiving element 17.

  2 and 3 are diagrams for explaining the operation of the detection unit 102 in FIG. 1. FIG. 2 shows the operation of the P-polarized light when white display is performed, and FIG. 3 shows the case when black display is performed. The operation of the S-polarized light will be described. 2 and 3, the naturally polarized light 31, the illumination optical system 12, the polarizing plate 13, the S polarized light 31 S, the P polarized light 32 P emitted from the light modulation element 14, the S polarized light 32 S, and the polarized light separating means 15 are emitted. The P-polarized light 33P, the reflected S-polarized light 33S, and the polarization separation surface 30 are shown.

  FIG. 2 is an operation explanatory diagram when white display is performed. Naturally polarized light 31 is unified into S-polarized light 31S by the illumination optical system 12, and passes through the polarizing plate 13 that transmits only the S-polarized light 31S. , And enters the light modulation element 14. At this time, since the white display is selected in the light modulation element 14, the polarization direction of the S-polarized light 31S is rotated by 90 ° to become the P-polarized light 32P and is emitted from the light modulation element 14 to separate the polarization. The light enters the means 15. The polarization separation surface 30 of the polarization separation means 15 has a function of transmitting polarized light whose polarization direction is parallel to the paper surface and reflecting polarized light whose polarization direction is perpendicular to the paper surface. The light is transmitted through the polarization separation surface 30 and emitted from the emission surface 21 of the polarization separation means 15 as P-polarized light 33P.

  FIG. 3 is an operation explanatory diagram when black display is performed. As in FIG. 2, the S-polarized light 31 </ b> S that has passed through the polarizing plate 13 enters the light modulation element 14. At this time, since the black display is selected in the light modulation element, the polarization direction does not rotate, and the S-polarized light remains as S-polarized light 32S, which exits the light modulation element 14 and enters the polarization separation means 15. To do. Since the polarization separation surface 30 has a function of reflecting polarized light whose polarization direction is perpendicular to the paper surface, the S-polarized light 32S is reflected by the polarization separation surface 30 and the optical path is bent by 90 ° to receive it as S-polarized light 33S. It is incident on the element 17 and illuminance is detected. At this time, if only the light-emitting element whose illuminance is to be detected is turned on, the illuminance of that light-emitting element alone can be detected. Can be detected. Since the amount of current output to the control unit 100 changes depending on the level of illuminance detected by the light receiving element 17, the amount of light and the light amount ratio of each color are calculated by monitoring the amount of change with the control unit 100. As described above, since the light amount on the optical path can be measured for each color, even when the light amount of each color changes due to the deterioration of the light emitting element, the control unit 100 calculates the light amount ratio and optimizes it. The light source can be controlled under various driving conditions, and the optimum white balance can be maintained.

  FIG. 4 is a schematic configuration diagram of a modification of the projection display device according to the first embodiment of the present invention. In FIG. 4, the projection display apparatus 2 includes a light source unit 101 including an R color light source 200R, a G color light source 200G, a B color light source 200B, and a color composition unit 11 having a plurality of light emitting elements, an illumination optical system 12, and a polarizing plate. 13, a light modulation element 14, a detection unit 102, an optical system 52 having a projection optical system 16, and a control unit 100, and the detection unit 102 includes a polarization separation means 15 and a light receiving element 17. A lens for controlling light from each light source may be arranged to be paired with each light emitting element.

  4 differs from the projection display device 1 of the first embodiment shown in FIG. 1 only in the number of light emitting elements constituting each of the color light sources 200R, 200G, and 200B. Since it is the same as that of the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted. The operation of the projection display device 2 shown in FIG. 4 is also the same as the operation of the projection display device 1 of the first embodiment, and a description thereof will be omitted. In this modification, a plurality of light emitting elements are used for each of the R color light source 200R, the G color light source 200G, and the B color light source 200B. At this time, the degree of deterioration of the individual light emitting elements is different for the same color light source. Even if the amount of light of each color changes, the detection unit 102 measures the amount of light of each color, and the control unit 100 calculates the light amount ratio and controls the light source under optimal driving conditions, so that the optimal white balance is maintained. It is possible.

  Next, a method for adjusting the light amount of each color will be described. When the chromaticity coordinates of the light emission colors of the R, G, and B color light sources are known, determining the chromaticity coordinates of the mixed color light determines the light quantity ratio of each color light source to be controlled. Further, when the light quantity ratio of each color light source is measured, the chromaticity coordinates of the mixed color light can be calculated. Note that the chromaticity coordinates of the emission colors of the R, G, and B color light sources may be fixed depending on the specifications of the light source. In order to take into account individual light source differences, chromaticity coordinates may be measured for each light source and reflected in the calculation. If the deviation of the chromaticity coordinates of the emission color due to the light source driving conditions such as temperature and driving current is taken into consideration, data may be stored in advance and reflected in the calculation according to the driving conditions.

  Hereinafter, in order to simplify the description, the chromaticity coordinates of the emission colors of the R, G, and B color light sources are fixed. The linearly polarized light forming the white display from the light modulation element 14 is projected from the polarization separation means 15 onto the screen (not shown) through the projection optical system 16. Further, the linearly polarized light forming the black display from the light modulation element 14 is reflected by the polarization separation surface 30 of the polarization separation means 15 and travels toward the light receiving element 17. Accordingly, when the entire surface of the light modulation element 14 is displayed in black, light that should be directed to the projection optical system 16 is directed to the light receiving element 17 when the entire surface of the light modulation element is displayed in white.

  When adjusting the white balance, the entire surface of the light modulation element 14 is displayed in black, and the output of the light receiving element 17 corresponding to each color at that time is monitored by the control unit 100 to adjust the light amount of each color light source. As the adjustment of the amount of light source, there are methods such as adjusting the luminous flux by controlling the current supplied to the light emitting element, adjusting the duty ratio of the light emitting time, and controlling the number of lighting of the light emitting element.

  According to the present invention, automatic calculation of white chromaticity coordinates using each color light source, automatic adjustment of white balance, automatic adjustment of color reproduction range, automatic adjustment of brightness while maintaining white balance, VT of the light modulation element Automatic calculation of characteristic correction data can be performed. The VT characteristic is a characteristic showing the relationship between the voltage V of the liquid crystal panel of the light modulation element 14 and the transmittance T. A voltage is applied to drive the liquid crystal panel and the amount of light transmitted is controlled according to the voltage level. For example, the relationship between the transmittance and the voltage is not necessarily linear, so the transmittance is linear. It is necessary to correct the voltage level. Alternatively, so-called gamma correction may be performed by making the relationship between transmittance and voltage non-linear.

The above-described operation can be executed in response to the following trigger.
1) Manual trigger via user interface such as operation button or communication port 2) Automatic trigger generated when power is turned on 3) Automatic trigger generated when video signal input is switched 4) Periodically generated by usage time monitoring function or clock Automatic trigger to be generated 5) Automatic trigger to be generated periodically in synchronization with the video signal Next, a method of adjusting the light quantity according to the first embodiment of the present invention will be described. FIG. 5 is a schematic block configuration diagram centering on a control unit for explaining the light amount adjustment method according to the first embodiment of the present invention. The control unit 100 has a control circuit 500 as a center, a sample hold circuit 501 to which information of the light receiving element 17 is input, an optical modulation element driving circuit 502 controlled by the control circuit 500, a VT characteristic correction circuit 503, and a video signal. Input video signal processing circuit 504, CPU 505 for controlling the entire processing, temporary storage memory 506, nonvolatile memory 507, user interface 508, R color light source drive circuit 509R for driving R color light source 10R, and G color light source 10G are driven. The color light source drive circuit 509G for driving the B color light source drive circuit 509B for driving the B color light source 10B is provided, and the color light emitted from each color light source 10R, 10G, 10B is input to the light receiving element 17 via the light conversion element 14. To do.

  The control circuit 500 controls each block while synchronizing the control timing. The nonvolatile memory 507 stores necessary setting conditions. For example, the sensitivity characteristics (illuminance-output level characteristics) of the light receiving element for each color (each wavelength band), white chromaticity information-RGB light quantity ratio characteristics, color reproduction range information-RGB primary light RGB ratio characteristics, color reproduction range information -RGB light quantity ratio characteristic of G primary color, color reproduction range information-RGB light quantity ratio characteristic of B primary color, VT characteristic correction information for each color (for each wavelength band) of the light modulation element, and the like.

Next, each mode of control will be described individually.
[White chromaticity coordinate automatic calculation mode]
FIG. 6 is a flowchart at the time of the white chromaticity coordinate automatic calculation mode operation. When the white chromaticity coordinate automatic calculation mode is started (S101), the light modulation element drive circuit 502 sets the light modulation element 14 to black display (S102), and each color light source drive circuit 509 turns on the G color light source 10G. The R color light source 10R and the B color light source 10B are turned off (S103), the output of the light receiving element 17 is input to the sample hold circuit 501, and the G color illuminance is obtained from the prestored data (S104). Next, the R color light source 10R is turned on, the G color light source 10G and the B color light source 10B are turned off (S105), and the output of the light receiving element 17 is input to the sample hold circuit 501 to obtain the R color illuminance ( S106). Next, the B color light source 10B is turned on, the R color light source 10R and the G color light source 10G are turned off (S107), and the output of the light receiving element 17 is input to the sample hold circuit 501 to obtain the illuminance of B color ( S108). White chromaticity coordinates are calculated from the obtained illuminance ratios of R, G, and B colors (S109), the calculated white chromaticity coordinates are notified (S110), and the process ends (S111). The destination for notifying the calculated white chromaticity coordinate information may be displayed on an operation panel (not shown) via the user interface 508 or may be output to a communication port (not shown). . Further, it may be displayed on the projected image via the projection optical system 16.
[Automatic white balance adjustment mode]
FIG. 7 is a flowchart at the time of the white balance automatic adjustment mode operation. The white balance automatic adjustment mode is executed corresponding to predetermined white chromaticity information. When the white balance automatic adjustment mode is started (S201), the reference R / G light amount ratio and the reference B / G light amount ratio are obtained from predetermined white chromaticity information stored in the nonvolatile memory 507 (S202), and the light modulation element is driven. The light modulation element 14 is set to black display by the circuit 502 (S203), the G color light source 10G is turned on by each color light source driving circuit 509, the R color light source 10R and the B color light source 10B are turned off (S204), and light is received. The output of the element 17 is input to the sample hold circuit 501 to obtain the G color illuminance (S205). Next, the R color light source 10R is turned on, the G color light source 10G and the B color light source 10B are turned off (S206), and the output of the light receiving element 17 is input to the sample hold circuit 501 to obtain the R color illuminance ( S207). Here, the control circuit 500 compares the R color illuminance / G color illuminance with the reference R / G light intensity ratio (S208), and if the R color illuminance / G color illuminance is less than the reference R / G light intensity ratio, the R color light source. The drive circuit 509R increases the light amount of the R color light source 10R, returns to step S207, obtains the R color illuminance, and compares again in step 208 (S209), and the R color illuminance / G color illuminance is the reference R / G light amount. If larger than the ratio, the R color light source drive circuit 509R reduces the light amount of the R color light source 10R, returns to step S207, obtains the R color illuminance, and compares again in step 208 (S210). If the R color illuminance / G color illuminance is the same as the reference R / G light quantity ratio, the B color light source 10B is turned on, the R color light source 10R and the G color light source 10G are turned off (S211), The output is input to the sample and hold circuit 501 to obtain the B color illuminance (S212). Here, the B color illuminance / G color illuminance is compared with the reference B / G light amount ratio (S213). If the B color illuminance / G color illuminance is less than the reference B / G light amount ratio, the light amount of the B color light source 10B is calculated. In step S212, the illuminance of B color is obtained and compared again in step 213 (S214). If the B color illuminance / G color illuminance is greater than the reference B / G light amount ratio, the light amount of the B color light source 10B After returning to step S212, the illuminance of the B color is obtained, and the comparison is performed again in step 213 (S215). If the B color illuminance / G color illuminance is the same as the reference B / G light quantity ratio, the white balance is adjusted and the white balance automatic adjustment mode is terminated (S216).

White chromaticity information may be fixed, and white balance deviation due to changes over time or temperature may be automatically corrected. The corrected driving condition may be stored in the nonvolatile memory 507. The white chromaticity information may be selectable by the user via the user interface 508. Further, in the case of a projection display device having a plurality of video input terminals, the selection may be made depending on which video input terminal is selected. For example, when selecting a video terminal, it may be adapted to the NTSC standard, and when selecting an RGB terminal, it may be adapted to the sRGB standard.
[Automatic color reproduction range adjustment mode]
FIG. 8 is a flowchart when the color reproduction range automatic adjustment mode is operated, FIG. 9A is a flowchart when the G primary color adjustment subroutine in FIG. 8, and FIG. 9B is a flowchart when the R primary color adjustment subroutine in FIG. FIG. 9C is a flowchart when the B primary color adjustment subroutine in FIG. 8 is operated.

  When the chromaticity coordinates of the three primary colors that determine the color reproduction range are determined, the light quantity ratios of the R, G, and B color lights are determined according to the chromaticity coordinates of the respective primary colors. For example, when it is desired to make the chromaticity coordinates of the three primary colors G different from the chromaticity coordinates of the G light source, the light from the R, G, and B light sources mixed at a predetermined light quantity ratio is changed to the three primary colors G light. That's fine.

  When the color reproduction range automatic adjustment mode is started (S301), the reference R / G light quantity ratio, the reference B / G light quantity ratio, and the R primary color reference for the G primary color are obtained from the predetermined color reproduction range information stored in the nonvolatile memory 507. The G / R light quantity ratio and the reference B / R light quantity ratio, the reference G / B light quantity ratio and the reference R / B light quantity ratio of the primary color B are obtained (S302), and the light modulation element drive circuit 502 makes the light modulation element 14 display black. Set (S303), enter the G primary color adjustment subroutine (S304), the R primary color adjustment subroutine (S305), and the B primary color adjustment subroutine (S306). As a result, the color reproduction range automatic adjustment mode is terminated (S307).

  In the G primary color adjustment subroutine (S304), when the G primary color adjustment subroutine is started (S401), the G color light source 10G is turned on by each color light source driving circuit 509, and the R color light source 10R and the B color light source 10B are turned off (S402). ), The output of the light receiving element 17 is input to the sample hold circuit 501, and the illuminance of G color is obtained (S403). Next, the R color light source 10R is turned on, the G color light source 10G and the B color light source 10B are turned off (S404), and the output of the light receiving element 17 is input to the sample hold circuit 501 to obtain the R color illuminance ( S405). Here, the control circuit 500 compares the R color illuminance / G color illuminance with the reference R / G light intensity ratio (S406), and if the R color illuminance / G color illuminance is less than the reference R / G light intensity ratio, the R color light source. The drive circuit 509R increases the light amount of the R color light source 10R, returns to step S405, obtains the R color illuminance, and compares again in step S406 (407), and the R color illuminance / G color illuminance is the reference R / G light amount. If larger than the ratio, the light amount of the R color light source 10R is decreased by the R color light source driving circuit 509R, the process returns to step S405, the R color illuminance is obtained, and the comparison is performed again in step S406 (S408). If the R color illuminance / G color illuminance is equal to the reference R / G light quantity ratio, the B color light source 10B is turned on, the R color light source 10R and the G color light source 10G are turned off (S409), and the light receiving element 17 The output is input to the sample and hold circuit 501 to obtain the illuminance of B color (S410). Here, the B color illuminance / G color illuminance is compared with the reference B / G light amount ratio (S411). If the B color illuminance / G color illuminance is less than the reference B / G light amount ratio, the light amount of the B color light source 10B is calculated. In step S410, the illuminance of B color is obtained and compared again in step S411 (S412). If the B color illuminance / G color illuminance is larger than the reference B / G light amount ratio, the light amount of the B color light source 10B And the process returns to step 410 to obtain the illuminance of the B color, and the comparison is performed again in step S411 (S413). If the B color illuminance / G color illuminance is the same as the reference B / G light amount ratio, the G primary color adjustment is completed and the G primary color adjustment subroutine is terminated (S414).

  The R primary color adjustment subroutine (S305) and the B primary color adjustment subroutine (S306) are the same as the G primary color adjustment subroutine except that the colors selected in each step are different, so that the description thereof is omitted.

The color reproduction range may be fixed, and the RGB light quantity balance shift due to changes over time or temperature may be automatically corrected. The corrected driving condition may be stored in the nonvolatile memory 507. The user may be able to select via the user interface 508. Further, in the case of a projection display device having a plurality of video input terminals, the selection may be made depending on which video input terminal is selected. For example, when selecting a video terminal, it may conform to the NTSC standard, and when selecting an RGB terminal, it may conform to the sRGB standard.
[Automatic brightness adjustment mode while maintaining white balance]
When the R color light source 10R, the G color light source 10G, and the B color light source 10B are used, the light amount of the G color light source 10G is adjusted to a predetermined brightness, and the R color light source light amount is adjusted at the same magnification as the change rate of the G color light amount. If each of the B light source amounts is changed, the brightness can be changed while maintaining the white balance.

In addition, by executing this automatic brightness adjustment mode after executing the automatic white balance adjustment mode, it is possible to automatically correct the brightness shift due to changes over time, temperature, or the like. The corrected driving condition may be stored in a nonvolatile memory. Note that the automatic brightness adjustment mode can also be applied when a white light source is used.
[V-T characteristic correction data automatic calculation mode of light modulation element]
FIG. 10 is a flowchart at the time of VT characteristic correction data automatic calculation mode operation, FIG. 11-A is a flowchart at the time of G color VT characteristic measurement subroutine operation in FIG. 10, and FIG. 11-B is in FIG. FIG. 11C is a flowchart at the time of the operation of the B color VT characteristic measurement subroutine in FIG. 10.

  When the VT characteristic correction data automatic calculation mode is started (S701), the control circuit 500 does not perform correction in the VT characteristic correction circuit 503 (S702). Next, the control circuit 500 enters the G color VT characteristic measurement subroutine (S703), the R color VT characteristic measurement subroutine (S704), and the B color VT characteristic measurement subroutine (S705). Executes correction in the VT characteristic correction circuit 503 (S706), and ends the VT characteristic correction data automatic calculation mode (S707).

  In the G color VT characteristic measurement subroutine (S703), when the G color VT characteristic measurement subroutine is started (S801), the G color light source 10G is turned on by each color light source drive circuit 509, and the R color light source 10R and the B color light source are turned on. 10B is turned off (S802), and the video signal processing circuit 504 sets the video signal to a predetermined level stored in the nonvolatile memory 507 (the level is changed according to the number of loops) (S803). The output of the light receiving element 17 is input to the sample and hold circuit 501 to obtain the G color illuminance and stored in the temporary storage memory 506 (S804). It is checked whether or not all predetermined video signal levels have been measured (S805). If there is an unmeasured video signal level (No in S805), the process returns to step S803 to change the level and output the light receiving element 17 to the sample hold circuit 501. The G color illuminance is input and obtained and stored in the temporary storage memory 506 (S804). It is checked whether all the predetermined video signal levels have been measured (S805).

  If all measurements have been completed in step S805 (S805 Yes), G color illuminance information stored in temporary storage memory 506 is read to calculate G color VT characteristic correction data (S806). The color VT characteristic correction data is stored in the nonvolatile memory 507 (S807), and the G color VT characteristic measurement subroutine is terminated (S808).

  The R color VT characteristic measurement subroutine (S704) and the B color VT characteristic measurement subroutine (S705) are the same as the G color VT characteristic measurement subroutine except that the color selected in each step is different. Is omitted.

  Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 12 is a schematic configuration diagram of the projection display apparatus according to the second embodiment of the present invention, and FIG. 13 is a modification of the projection display apparatus according to the second embodiment of the projection display apparatus of the present invention. It is a typical block diagram of an example. In the second embodiment, only the configuration of the light receiving element 17 of the detection unit 102 of the first embodiment is different, and the other configurations and operations are the same. Omitted.

  The light receiving element 17 of the detection unit 102 according to the first embodiment uses one element having sensitivity to each color light of R, G, and B. In the detection unit 103 according to the second embodiment, R is used. It is composed of three light receiving elements, a color light receiving element 17R, a G color light receiving element 17G, and a B color light receiving element 17B, and the reflected light 20B from the polarization separation means 15 enters all the light receiving elements and is selected. In the modification of the second embodiment, a color separation optical system 18 is provided to divide the reflected light 20B from the polarization separation means 15 for each color of R, G, B, and the separated R, G, B colors. The three light receiving elements of R color light receiving element 17R, G color light receiving element 17G, and B color light receiving element 17B are provided in the optical paths of the separated color lights. In the first embodiment, the R, G, and B color light sources need to be turned on one by one. However, in the second embodiment, the R, G, and B color light sources can be turned on at the same time. The light quantity ratio can be detected.

  Next, a third embodiment of the present invention will be described with reference to the first embodiment and the drawings. In the first and second embodiments described above, the example in which each adjustment mode is executed without displaying an image has been described. However, in the third embodiment, each adjustment mode can be executed while displaying an image. Is possible. In the third embodiment, black is displayed on the light modulation element 14 for an instant for each field period during video display, and the output level of the light receiving element 17 at that moment is stored in the sample hold circuit 501 of the control unit 100. To analyze.

  Next, a fourth embodiment of the present invention will be described with reference to the first embodiment and the drawings. In the first and second embodiments described above, an example has been described in which black display is performed on the light modulation element when each adjustment mode is executed. In the fourth embodiment, each adjustment mode can be executed without black display on the light modulation element for adjustment. In the fourth embodiment, the brightness of the negative image of the image displayed by the light modulation element 14 is dynamically detected by the optical sensor, and the APL (Average Picture Level) of the signal obtained by inverting the level of the input video signal. Each adjustment mode is executed by comparison with the average luminance level of the input signal.

  In the embodiments so far, the projection display apparatus having one light modulation element has been described. However, it is obvious that the present invention can be applied to a projection display apparatus having a plurality of light modulation elements.

1 is a schematic configuration diagram of a projection display device according to a first embodiment of the present invention. It is a figure for demonstrating operation | movement of the detection part in FIG. 1, and shows operation | movement of the P polarized light at the time of performing a white display. It is a figure for demonstrating operation | movement of the detection part in FIG. 1, and shows operation | movement of S polarized light at the time of performing black display. It is a typical block diagram of the modification of the projection type display apparatus of 1st Embodiment of this invention. It is a typical block block diagram centering on the control part for demonstrating the light quantity adjustment method of the 1st Embodiment of this invention. It is a flowchart at the time of white chromaticity coordinate automatic calculation mode operation | movement. It is a flowchart at the time of white balance automatic adjustment mode operation. 6 is a flowchart at the time of color reproduction range automatic adjustment mode operation. FIG. 9 is a flowchart at the time of a G primary color adjustment subroutine operation in FIG. 8. FIG. FIG. 9 is a flowchart at the time of an R primary color adjustment subroutine operation in FIG. 8. FIG. FIG. 9 is a flowchart at the time of a B primary color adjustment subroutine operation in FIG. 8. FIG. It is a flowchart at the time of VT characteristic correction data automatic calculation mode operation | movement. FIG. 11 is a flowchart at the time of a G color VT characteristic measurement subroutine operation in FIG. 10. FIG. 11 is a flowchart at the time of an R color VT characteristic measurement subroutine operation in FIG. 10. It is a figure which shows the flowchart at the time of the B color VT characteristic measurement subroutine operation | movement in FIG. It is a typical block diagram of the projection type display apparatus of the 2nd Embodiment of this invention. It is a typical block diagram of the modification of the projection type display apparatus of 2nd Embodiment of the projection type display apparatus of this invention. It is a typical block diagram which shows the structure of the optical system of the conventional projection display apparatus.

Explanation of symbols

1, 2, 3, 4, 5 Projection display device 10R, 200R R color light source 10G, 200G G color light source 10B, 200B B color light source 11 Color composition means 12 Illumination optical system 13 Polarizing plate 14 Light modulation element 15 Polarization separation means DESCRIPTION OF SYMBOLS 16 Projection optical system 17, 17R, 17G, 17B Light receiving element 18 Color separation optical system 20A Transmitted light of the polarization separation surface 30 20B Reflected light of the polarization separation surface 30 21 Output surface of the polarization separation means 15 30 Polarization separation surface 31 Naturally polarized light 31S S-polarized light transmitted through the polarizing plate 32S S-polarized light transmitted through the light modulator element 32P P-polarized light transmitted through the light modulator element 33S S-polarized light reflected from the polarization separation surface 30 33P transmitted through the polarization separation surface 30 P-polarized light 40 Analyzer 51, 52, 53, 54, 55 Optical system 100 Control unit 101 Light source unit 102, 103, 104 Detection 500 control circuit 501 sample-and-hold circuits 502 light modulation element driving circuit 503 V-T characteristic correction circuit 504 video signal processing circuit 505 CPU
506 Temporary storage memory 507 Non-volatile memory 508 User interface 509R R color light source drive circuit 509G G color light source drive circuit 509B B color light source drive circuit S101-S111, S201-S216, S301-S307, S401-S414, S501-S514, S601 -S614, S701-S707, S801-S808, S901-S908, S1001-S1008 Step

Claims (12)

A light source unit;
Linear polarization means for converting light from the light source unit into linearly polarized light;
A light modulation element for modulating light from the linear polarization means;
Polarization separation means for separating the light from the light modulation element into first linearly polarized light and second linearly polarized light whose polarization directions are orthogonal to each other and emitting each of the light to different optical paths;
A projection optical system for projecting the first linearly polarized light emitted from the polarization separating means;
A light receiving element for detecting a received light amount of the second linearly polarized light emitted from the polarization separating means;
And a control unit configured to drive the light source unit and the light modulation element and control a light emission state of the light source unit according to a light reception amount detection state in the light receiving element.   2. The light source unit according to claim 1, comprising: a red light source that emits red light; a green light source that emits green light; a blue light source that emits blue light; and a color synthesis unit that synthesizes light from each of the color light sources. Projection display device.   The projection display device according to claim 2, wherein each of the color light sources has at least one light emitting element.   The projection display device according to claim 3, wherein the light emitting element is a light emitting diode.   The projection display device according to claim 3, wherein the light emitting element is a semiconductor laser.   The projection display apparatus according to claim 1, wherein the light modulation element is a liquid crystal device.   2. The projection display device according to claim 1, wherein the polarization separation unit has a polarization separation surface made of a dichroic film that transmits the first linearly polarized light and reflects the second linearly polarized light.   The projection display device according to claim 1, wherein the light receiving element is a photodiode.   The projection display device according to claim 1, wherein the light receiving element is a phototransistor.   The projection display device according to claim 1, wherein the light receiving element is provided corresponding to each of red, green, and blue colors.   The control means compares the light amounts of the light emitting elements of red, green, and blue colors based on the received light amount of the second linearly polarized light detected by the light receiving element, and maintains the white balance of each color of the light source. The projection display device according to claim 1, wherein the driving condition is controlled.   The projection display device according to any one of claims 1 to 11, wherein a polarizing plate is disposed between the polarization separation means and the projection optical system.

Images