JP2011223350A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device capable of sufficiently adjusting image quality and keeping the quality of images good.SOLUTION: A projector is equipped with a lamp 21, liquid crystal panels 23, 24, and 25 that modulate light from the lamp 21 in accordance with a video signal and generate video light, a light-shielding shutter 27 that blocks or opens light path of the video light, and multiple sensor units 28 decentrally located on the light-shielding shutter 27. The sensor units 28 contain a chromaticity sensor 281 and an illuminance sensor 282. A CPU 101 adjusts driving signals of panel driving circuits 106, 107, and 108 so that chromaticity measured by each of the chromaticity sensors 281 is equal with the light-shielding shutter 27 irradiated with the video light based on an all-white test image. In addition, the driving signals of the panel driving circuits 106, 107, and 108 are adjusted so that illuminance measured by each of the illuminance sensors 282 is equal.

Description

  The present invention relates to a projection display device that modulates light from a light source and projects the light onto a projection surface.

  A projection display device (hereinafter referred to as a “projector”) modulates light from a light source with a light modulation element (such as a liquid crystal panel) and projects the modulated light (hereinafter referred to as “image light”) onto a projection surface. It has the composition to do. For example, a lamp light source is used as the light source, and a liquid crystal panel is used as the light modulation element, for example.

  In these light sources and light modulation elements, deterioration due to aging is inevitable. When the light source deteriorates and its output decreases, the brightness of the projected image decreases. In addition, when the light modulation element is deteriorated, the projected image is reduced in luminance and chromaticity. As a result, there is a problem that the image quality of the projected image is deteriorated.

In order to solve such a problem, the projector may be provided with a configuration for eliminating the deterioration of the image quality based on the secular change. For example, a lens cover that opens and closes the light exit surface is provided on the light exit surface side of the projection lens, and a light detection means that detects the state of image quality on the back surface of the lens cover (
For example, a chromaticity sensor) is arranged. The state of the image quality is detected by the light detection means, and the image quality is corrected based on the detection result (see Patent Document 1).

JP 2008-309835 A

  By the way, a decrease in luminance and a change in chromaticity do not necessarily occur uniformly in the entire projected image. The projector is designed so that the light from the light source is evenly applied to the liquid crystal panel. However, such a design also tends to increase the illuminance at the center of the liquid crystal panel. For this reason, the central portion of the liquid crystal panel is likely to be deteriorated, and this deterioration not only causes a decrease in luminance and a change in chromaticity, but also tends to cause luminance unevenness and color unevenness.

  However, in the projector having the above configuration (Patent Document 1), the image quality such as chromaticity is corrected based on the detection result by one light detection unit arranged on the back surface of the lens cover. Unevenness and chromaticity unevenness cannot be corrected. Therefore, such a projector cannot sufficiently adjust the image quality, and therefore there is a possibility that the image quality cannot be kept good.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a projection display device that can sufficiently adjust the image quality and can maintain good image quality.

The present invention relates to a projection display device that projects an image on a projection surface. The projection display device of the present invention includes a light source, a light modulation unit that generates light by modulating light from the light source based on a video signal, a shutter that blocks or opens an optical path of the video light, and the shutter And a plurality of detection units that output detection signals corresponding to the image light irradiated on the shutter, and the detection signals from the plurality of detection units in a state where the image light is blocked by the shutter. And an image quality adjusting unit that adjusts the image quality of the projected image based on the image quality.

  According to the projection display device of the present invention, since the image quality unevenness of the projection image can be detected by comparing the detection signals from the respective detection units, not only the luminance reduction of the entire projection image but also the luminance unevenness and the color. The image quality can be adjusted so as to eliminate the image quality unevenness such as the unevenness of the degree.

  In the projection display device according to the aspect of the invention, each of the detection units may include a chromaticity detection unit that outputs a detection signal corresponding to the chromaticity of the video light. In this case, the image quality adjustment unit acquires the detection signal from each chromaticity detection unit in a state where the video light based on the test image with uniform chromaticity is irradiated on the shutter, and acquires the acquired A chromaticity adjustment value for adjusting the chromaticity of the projected image is set so that the difference between the detection signals becomes small.

  With such a configuration, it is possible to reduce the chromaticity unevenness of the projected image.

  In the projection display device according to this configuration, the image light based on the plurality of test images having different luminances is irradiated to the shutter, and the image quality adjustment unit includes the image light based on each test image. The chromaticity adjustment value for the corresponding luminance is acquired in each state irradiated with, and the chromaticity of the projection image can be adjusted based on the acquired chromaticity adjustment value.

  With such a configuration, it is possible to change the degree of chromaticity adjustment according to the brightness of the projected image. Therefore, the image quality can be kept better.

  In the projection display device according to the aspect of the invention, each of the detection units may include a luminance detection unit that outputs a detection signal corresponding to the luminance of the video light. In this case, the image quality adjustment unit acquires the detection signal from each luminance detection unit in a state where the image light based on the test image with uniform luminance is applied to the shutter, and the acquired detection A brightness adjustment value for adjusting the brightness of the projected image is set so that the signal difference is reduced.

  With such a configuration, uneven brightness in the projected image can be reduced.

  In the projection display device according to this configuration, the shutter is irradiated with the video light based on the plurality of test images having different luminances, and the image quality adjustment unit receives the video light based on each test image. In each irradiated state, the brightness adjustment value for the corresponding brightness is acquired, and the brightness of the projection image is adjusted based on the acquired brightness adjustment value.

  With such a configuration, it is possible to change the brightness adjustment according to the brightness of the projected image. Therefore, the image quality can be kept better.

  The projection display device of the present invention may be configured to include a projection unit for enlarging and projecting the image light. In this case, the shutter may be configured to be disposed between the light modulation unit and the projection unit.

With such a configuration, the image light before being incident on the projection unit is irradiated to the detection unit (the chromaticity detection unit or the luminance detection unit), so the image light is attenuated or influenced by light outside the machine. It is hard to receive,
It is possible to accurately detect the state of image quality (chromaticity and luminance).

As described above, according to the present invention, it is possible to provide a projection display device that can sufficiently adjust the image quality and can maintain a good image quality.

  The effects and significance of the present invention will become more apparent from the following description of embodiments. However, the following embodiment is merely an example when the present invention is implemented, and the present invention is not limited to what is described in the following embodiment.

1 is an external perspective view showing a configuration of a projector according to an embodiment. It is a figure which shows the structure of the optical engine which concerns on embodiment. It is a figure which shows the structure of the light-shielding shutter and sensor unit which concern on embodiment. It is a figure which shows the structure of the light-shielding shutter and sensor unit which concern on embodiment. It is a block diagram which shows the structure of the control circuit part which concerns on embodiment. It is a figure which shows the data table in which the data for the test image used in the image quality adjustment mode which concerns on embodiment were memorize | stored. It is a flowchart which shows the control processing in the image quality adjustment mode which concerns on embodiment. It is a flowchart which shows the control processing in the image quality adjustment mode which concerns on embodiment. It is a figure which shows the state by which the pixel area of the liquid crystal panel which concerns on embodiment was divided corresponding to the sensor unit. It is a figure which shows the specific example of image quality adjustment using the test image 1 which concerns on embodiment. It is a figure for demonstrating the chromaticity nonuniformity correction | amendment and chromaticity correction | amendment in the specific example of the image quality adjustment which concerns on embodiment. It is a figure showing the correction coefficients (alpha), (beta), and (gamma) of the drive signal determined for every area | region A1-A9 in each liquid crystal panel which concerns on embodiment. It is a figure for demonstrating preparation of the correction coefficient table which concerns on embodiment. It is a figure for demonstrating the example of a change of a projector. It is a figure for demonstrating the example of a change of a projector. It is a figure for demonstrating the other example of a change of a projector.

  Hereinafter, a projector according to an embodiment will be described with reference to the drawings.

  FIG. 1 is an external perspective view showing the configuration of the projector. Referring to FIG. 1, the projector includes a cabinet 10 having a horizontally long and substantially rectangular parallelepiped shape. In the cabinet 10, a projection window 11 is formed on the left side of the front surface, and exhaust ports 12 and 13 for exhausting air from inside the cabinet 10 are formed on the right side and the right side surface of the front surface, respectively. Further, on the upper surface of the cabinet 10, an operation unit 14 provided with a plurality of operation buttons such as a main switch is provided.

  An optical engine 20 and a projection lens 30 are arranged inside the cabinet 10. The optical engine 20 generates video light modulated by the video signal. A projection lens 30 is attached to the optical engine 20, and a front end portion of the projection lens 30 is exposed forward from the projection window 11. The projection lens 30 enlarges and projects the image light generated by the optical engine 20 onto a screen arranged in front of the projector.

  FIG. 2 is a diagram showing a configuration of the optical engine 20.

  As shown in the figure, the optical engine 20 includes a lamp 21, a light guide optical system 22, three transmissive liquid crystal panels 23, 24, and 25, a dichroic prism 26, and a light shielding shutter 27. In addition, polarizing plates (not shown) are arranged on the incident side and the emission side of the liquid crystal panels 23, 24, and 25.

  The lamp 21 is, for example, a metal halide lamp or a xenon lamp. White light emitted from the lamp 21 is transmitted through the light guide optical system 22 to light in the red wavelength band (hereinafter referred to as “R light”), light in the green wavelength band (hereinafter referred to as “G light”), and blue wavelength. The light is separated into band light (hereinafter referred to as “B light”) and irradiated to the red liquid crystal panel 23, the green liquid crystal panel 24, and the blue liquid crystal panel 25, respectively. The R light, G light, and B light modulated by the liquid crystal panels 23, 24, and 25 are color-combined by the dichroic prism 26 and emitted as video light.

  In addition to the transmissive liquid crystal panels 23, 24, and 25, a reflective liquid crystal panel or a MEMS device can be used as the light modulation element constituting the optical engine 20. Further, the optical engine 20 may be configured by a single plate type optical system using one light modulation element and a color wheel, for example, instead of the three plate type optical system including the three light modulation elements as described above. it can.

  A light shielding shutter 27 is disposed between the exit surface of the dichroic prism 26 and the entrance surface of the projection lens 30.

  3 and 4 are diagrams showing the configuration of the light shielding shutter 27 and the sensor unit 28. FIG. FIGS. 3A and 3B are a front view and a side view, respectively, showing a state where the upper and lower shutters 271 and 272 are opened. 4A and 4B are a front view and a side view, respectively, showing a state where the upper and lower shutters 271 and 272 are closed. In FIG. 3A and FIG. 4A, the configuration of the drive mechanism M of the light shielding shutter 27 is not shown.

  With reference to FIGS. 3 and 4, the light-shielding shutter 27 includes an upper shutter 271, a lower shutter 272, and a drive mechanism M. The upper and lower shutters 271 and 272 both have a horizontally long rectangular shape, and are supported by a guide portion (not shown) so as to be slidable in the vertical direction in the figure. The vertical dimension of the lower shutter 272 is larger than the vertical dimension of the upper shutter 271. The upper shutter 271 and the lower shutter 272 are opened and closed by the drive mechanism M.

  As shown in FIGS. 3B and 4B, the drive mechanism M includes an upper rack 273, a reverse gear 274, an upper gear 275, a lower rack 276, a lower gear 277, and a drive motor 278. And a toothed belt 279.

  The upper rack 273 is attached to the upper shutter 271. A reversing gear 274 is connected to the upper rack 273, and an upper gear 275 is connected to the reversing gear 374. On the other hand, the lower rack 276 is attached to the lower shutter 272. A lower gear 277 is connected to the lower rack.

  The upper gear 275 and the lower gear 277 are connected to the motor gear 278a of the drive motor 278 by a toothed belt 279.

When the upper and lower shutters 271 and 272 are in an open state, the image light emitted from the dichroic prism 26 passes between the upper and lower shutters 271 and 272 as shown in FIG. 30 is incident. When the drive motor rotates from the open state as shown by the arrow in FIG. 3B, the gears 274, 275, and 277 rotate as shown by the arrow in FIG. 3B, and the upper shutter 271 moves downward. As it moves, the lower shutter 272 moves upward. Thus, as shown in FIG. 4, the upper and lower shutters 271 and 272 are closed.

  When the upper and lower shutters 271 and 272 are closed, the optical path of the image light emitted from the dichroic prism 26 is blocked by the upper and lower shutters 271 and 272 as shown in FIG. As a result, the image light is applied to the shutters 271 and 272.

  Three sensor units 28 are arranged on the upper shutter 271, and six sensor units 28 are arranged on the lower shutter 272. Each of these nine sensor units 28 is positioned at the center of each region when the region irradiated with the image light is divided into nine substantially equal parts as shown by the broken lines in FIG. That is, the sensor units 28 are distributed in the image light irradiation areas of the upper and lower shutters 271 and 272.

  Each sensor unit 28 includes a chromaticity sensor 281 and an illuminance sensor 282. The chromaticity sensor 281 includes three photodiodes each having sensitivity to R light, G light, and B light, and calculates chromaticity (x value, y value) from the detected R light, G light, and B light. A detection signal corresponding to the chromaticity is output. The illuminance sensor 282 detects the luminance of the image light and outputs a detection signal corresponding to the luminance.

  FIG. 5 is a block diagram illustrating a configuration of the control circuit unit 100.

  The projector is provided with a control circuit unit 100 for driving and controlling the lamp 21, the liquid crystal panels 23, 24, 25, and the like. The control circuit unit 100 includes a CPU 101, a memory 102, an operation input circuit 103, a video signal input unit 104, a video signal processing circuit 105, three panel drive circuits 106, 107 and 108, and a lamp output adjustment circuit 109. And a shutter drive circuit 110.

  The operation input circuit 103 outputs an input signal corresponding to the button operation of the operation unit 14 to the CPU 101.

  The video signal input unit 104 includes various input terminals corresponding to various video signals such as composite signals and RGB signals, and outputs video signals input from the outside to the video signal processing circuit 105.

  The video signal processing circuit 105 performs various adjustments such as processing for converting video signals other than RGB signals into RGB signals and gain adjustment of the video signals described later. Then, the adjusted R signal, G signal, and B signal are output to panel drive circuits 105, 106, and 107, respectively.

  The video signal processing circuit 105 generates a test image RGB signal from the test image data stored in the memory 102, and generates the generated test image R signal, G signal, and B signal, respectively, on the panel. Output to the control circuits 106, 107, 107.

  Each of the panel drive circuits 106, 107, and 108 generates a drive signal (drive voltage) corresponding to the R signal, the G signal, and the B signal according to the control signal from the CPU 101, and the corresponding liquid crystal panel according to the generated drive signal 23, 24 and 25 are driven.

  The lamp output adjustment circuit 109 drives the lamp 21 by outputting a drive voltage corresponding to the control signal from the CPU 101. The lamp 21 is lit with a luminance corresponding to the driving voltage. The lamp 21 is driven at a voltage lower than the maximum driving voltage at the beginning of use in consideration of a decrease in luminance due to aging.

  The shutter drive circuit 110 drives a drive motor 278 for the light shielding shutter 27 in accordance with a control signal from the CPU 101.

  The memory 102 includes a RAM, a ROM, and the like. The memory 102 stores a control program for giving a control function to the CPU 101. The CPU 101 controls each unit according to a control program stored in the memory 102.

  In the projector according to the present embodiment, when commercial power is turned on, power is supplied to the CPU 101 to enter a standby state. When the main switch of the operation unit 14 is operated in the standby state, the CPU 101 activates the lamp 21 and the liquid crystal panels 23, 24, and 25 to start operation. In this way, an image based on the video signal input from the outside is projected on the screen.

  In general, in a projector, due to deterioration due to aging of the lamp 21 and the liquid crystal panels 23, 24, and 25, a decrease in luminance and a change in chromaticity occur in a projected image. Therefore, in the present embodiment, an image quality adjustment mode for adjusting the image quality of the projected image with respect to such a decrease in luminance and a change in chromaticity is executed. For example, when the main switch is operated by the user, the image quality adjustment mode is executed before normal operation is started. Alternatively, it is executed when a user operates a key for executing an image quality adjustment mode provided in the operation unit 14.

  As shown in FIG. 6, the memory 102 is provided with a data table storing test image data used in the image quality adjustment mode. In the present embodiment, five test images (test image 1 to test image 5) having a single white color with different brightness are prepared.

  The test image 1 is an image made up of a single white color having the maximum luminance, and is generated by the RGB signal having the maximum gradation. The test image 2 is an image composed of a white color having a luminance of 75% of the maximum luminance, and is generated by an RGB signal having a maximum gradation of 75%. Hereinafter, the test image 3 to the test image 5 are images composed of a white color having a luminance of 50%, 25%, and 5% of the maximum luminance, respectively, and are 50%, 25%, and 5% of the maximum gradation, respectively. Generated by RGB signals.

  The data table stores target luminance and target chromaticity that should be detected by the sensor unit 28 when images of these five test images are projected. The target luminance is set for each test image. The target brightness and target chromaticity are set to factory shipments, but may be set by the user thereafter.

  7 and 8 are flowcharts showing the control processing in the image quality adjustment mode. FIG. 7 is a flowchart showing the flow of the entire control process, and FIGS. 8A to 8D are flowcharts showing specific processes of chromaticity unevenness correction, luminance unevenness correction, chromaticity correction, and luminance correction, respectively. It is.

Referring to FIG. 7, the CPU 101 first closes the light shielding shutter 27 (S11). Next, the CPU 101 activates the lamp 21 and the liquid crystal panels 23, 24, and 25 to output a test image (S12). That is, the CPU 101 activates the lamp 21 and the liquid crystal panels 23, 24, and 25, reads the data of the test image 1 from the memory 102, and sends it to the video signal processing circuit 105. Thereby, the video light of the test image 1 is output from the dichroic prism 26. The output image light is irradiated to each sensor unit 28 disposed in the light shielding shutter 27 as shown in FIG.

  First, the CPU 101 performs correction processing for chromaticity unevenness using the video light of the test image 1 (S13). That is, as shown in FIG. 8A, the CPU 101 first measures the chromaticity of the image light by each chromaticity sensor 281 (S131).

  As shown in FIG. 9, the pixel areas (panel areas) of the liquid crystal panels 23, 24, and 25 are divided into nine areas A1 to A9 corresponding to the sensor units 28. The CPU 101 adjusts the drive signals of the panel drive circuits 106, 107, and 108 for each of the areas A1 to A9 so that the chromaticities of the video light measured by the chromaticity sensors 281 are equal (S132). For example, the drive signals corresponding to the eight regions are adjusted so that the chromaticities corresponding to the eight regions other than the central region A5 are equal to the chromaticity corresponding to the region A5.

  The CPU 101 determines whether or not the chromaticities measured by the respective chromaticity sensors 281 are all equal (S133), and repeats the adjustment of the drive signal while measuring the chromaticity until the chromaticities are all equal (S131 to S131). S133).

  FIG. 10 shows a specific example of image quality adjustment using the video light of the test image 1.

  The figure illustrates the state of the image light in the three areas A5, A1, and A9 (strictly speaking, the arrangement position of the sensor unit 28) in FIG. In each figure of FIG. 10, the state of the luminance of the R light, G light, and B light constituting the image light is schematically shown by a bar graph. The brightness shown in these bar graphs is not detected by the illuminance sensor 282, but the brightness of the R light, G light, and B light before being synthesized by the dichroic prism 26 in FIG. It is shown in The illuminance sensor 282 detects not the brightness of the R light, the G light, and the B light, but the brightness of the image light obtained by combining the R light, the G light, and the B light.

  In the present embodiment, when the luminances of the R light, G light, and B light indicated by the bar graphs are the sizes indicated by the dotted lines in the figure, there is a condition that the luminance of the video light becomes the target luminance Z1. Is set. In addition, a condition is set that the chromaticity of the image light becomes the target chromaticity (XW, YW) when the luminances of the R light, G light, and B light shown in the bar graph are the same. However, the present invention is not limited to this condition, and when the luminances of the R light, the G light, and the B light indicated by the bar graphs have predetermined sizes, the luminance and chromaticity of the image light are respectively set to the target luminance Z1. And the target chromaticity (XW, YW) may be set.

  FIG. 10A shows a state before correction, that is, a state in which a decrease in luminance and a change in chromaticity occur in the projected image due to deterioration of the liquid crystal panels 23, 24, 25, and the like. FIG. 11A shows a state in which the chromaticities corresponding to the regions A5, A1, and A9 (strictly speaking, the arrangement positions of the sensor units 28) are deviated from the target chromaticities (XW, YW), respectively. It is shown using a chromaticity diagram.

For example, before correction, the chromaticity corresponding to the area A5 is (X5, Y5), the chromaticity corresponding to the area A1 is (X1, Y1), and the chromaticity corresponding to the area A9 is (X9, Y9). In this case, in the process of step S132 in FIG. 8A, the difference between X5 and X1 and the difference between Y5 and Y1 are obtained for the area A1. And the drive signal corresponding to area | region A1 is increased / decreased for every liquid crystal panel 23, 24, 25 so that this difference may become small. Similarly, for the region A9, the difference between X5 and X9 and the difference between Y5 and Y9 are obtained. And the drive signal corresponding to area | region A9 is increased / decreased for every liquid crystal panel 23, 24, 25 so that this difference may become small.

  Thereby, as shown in FIG. 10B, the ratio of the luminance of each RBG light in the region A1 and the region A9 becomes the same as the ratio of the luminance of each RBG light in the region A5, and as shown in FIG. The chromaticities corresponding to the two regions A5, A1, and A9 are all (X5, Y5). In addition, the broken line of FIG.10 (b) shows the brightness | luminance of R light, G light, and B light before chromaticity nonuniformity correction | amendment.

  Thus, the chromaticity corresponding to all the regions (strictly speaking, the arrangement position of the sensor unit 28) becomes equal, and the chromaticity unevenness is eliminated. In the present embodiment, the driving signal for the R light liquid crystal panel 23 is fixed, and chromaticity unevenness correction for each region is performed. That is, when correcting the chromaticity unevenness, the drive signals for the liquid crystal panels 24 and 25 for G light and B light are adjusted. Alternatively, the driving signal for the liquid panel other than the liquid crystal panel 23 for the R light may be fixed to correct the chromaticity unevenness, or the driving signal for any liquid crystal panel may be fixed. Chromaticity unevenness correction may be performed.

  Thereafter, based on the adjustment result, as shown in FIG. 12, the CPU 101 corrects drive signal correction coefficients α (αR1 to αR9, αG1 to αG9, αB1) related to chromaticity unevenness correction for each region of each liquid crystal panel. ~ ΑB9) is determined (S134). The correction coefficient α is different for each of the liquid crystal panels 23, 24, and 25 and is different for each of the regions A1 to A9. The correction coefficient α is obtained by the following equation.

  α = drive signal after chromaticity unevenness correction for each area (positioning position of sensor unit 28) of each liquid crystal panel / drive signal before chromaticity unevenness correction for each area (positioning position of sensor unit 28) of each liquid crystal panel (1)

  In the present embodiment, the correction coefficients αR1 to αR9, αG1 to αG9, and αB1 to αB9 thus obtained with respect to the arrangement position of the sensor unit 28 are the areas A1 of the liquid crystal panels 23, 24, and 25 corresponding to the sensor units 28. Applies to the entire A9. FIG. 12 is a diagram showing drive signal correction coefficients α, β, and γ determined for each of the regions A1 to A9 in each of the liquid crystal panels 23, 24, and 25.

  As described above, when the chromaticity corresponding to the central area A5 is used as a reference, the correction coefficients αR5, αG5, and αB5 corresponding to the area A5 are “1”. Further, in the case other than the region A5, when the chromaticity unevenness correction is performed by fixing the drive signal for the R light liquid crystal panel 23 as described above, correction coefficients αR1 to αR4 and αR6 to αR6 corresponding to the R light are corrected. αR9 is “1”. The correction coefficient α corresponds to the chromaticity adjustment value of the present invention.

  Returning to FIG. 7, the CPU 101 next performs a process for correcting luminance unevenness (S <b> 14). That is, as shown in FIG. 8B, the CPU 101 first measures the luminance of the image light by each illuminance sensor 282 (S141).

  CPU101 adjusts the drive signal of each panel drive circuit 106,107,108 for every area | region A1-A9 so that the brightness | luminance measured by each illumination intensity sensor 282 may become equal (S142). For example, the drive signals corresponding to the eight regions are adjusted so that the luminance corresponding to the eight regions other than the central region A5 is equal to the luminance corresponding to the region A5. The CPU 101 determines whether or not the luminances measured by the luminance sensors 282 are all equal (S143), and repeats the adjustment of the drive signal while measuring the luminances until all the luminances are equal (S141 to S143).

In the specific example shown in FIG. 10, when the process of step S142 is performed, the difference between the luminance corresponding to the region A5 and the luminance corresponding to the region A1 is obtained for the region A1, and the region is set so that the difference becomes small. The drive signal corresponding to A1 is increased or decreased by the same ratio for each of the liquid crystal panels 23, 24, and 25. Similarly, for the area A9, the difference between the luminance corresponding to the area A5 and the luminance corresponding to the area A9 is obtained, and the drive signal corresponding to the area A9 is supplied to each of the liquid crystal panels 23 and 24 so that the difference is reduced. , 25 are increased or decreased by the same rate.

  Thereby, as shown in FIG. 10C, the luminance of each RBG light in the region A1 and the region A9 is the same as the luminance of each RBG light in the region A5. In addition, the broken line of FIG.10 (c) shows the brightness | luminance of R light, G light, and B light before brightness nonuniformity correction | amendment.

  Thus, when the luminance corresponding to all the regions (strictly speaking, the arrangement position of the sensor unit 28) becomes equal and the luminance unevenness is eliminated, the CPU 101, as shown in FIG. A drive signal correction coefficient β (β1 to β9) related to luminance unevenness correction is determined (S144). The correction coefficient β is different for each of the regions A1 to A9, but is common to all the liquid crystal panels 23, 24, and 25. The correction coefficient β is obtained by the following equation.

  β = drive signal after luminance unevenness correction for each region of liquid crystal panel (arrangement position of sensor unit 28) / drive signal before correction of luminance unevenness for each region (arrangement position of sensor unit 28) of each liquid crystal panel (2) )

  Note that the denominator on the right side of Expression (2) is a drive signal after the chromaticity unevenness correction shown in FIG. 10B is performed.

  Since the correction coefficient β is common to all the liquid crystal panels 23, 24, and 25 as described above, the calculation of the above formula (2) may be performed for any one of the liquid crystal panels 23, 24, and 25. . That is, the correction coefficient β obtained based on the above formula (2) for any one of the liquid crystal panels 23, 24, and 25 is also applied to the other liquid crystal panels.

  In the present embodiment, the correction coefficients β1 to β9 thus obtained for the arrangement positions of the sensor units 28 are applied to the entire areas A1 to A9 of the liquid crystal panels 23, 24, and 25 corresponding to the sensor units 28.

  As described above, when the luminance corresponding to the central area A5 is used as a reference, the correction coefficient β5 corresponding to the area A5 is “1”. The correction coefficient β corresponds to the brightness adjustment value of the present invention.

  Returning to FIG. 7, the CPU 101 next performs chromaticity correction processing (S15). That is, as shown in FIG. 8C, the CPU 101 first measures chromaticity by the chromaticity sensor 281 corresponding to the central area A5 (S151).

  The CPU 101 adjusts the drive signals of the panel drive circuits 106, 107, and 108 so that the chromaticity measured by the central chromaticity sensor 281 becomes the target chromaticity (XW, YW) (S152). The CPU 101 determines whether or not the measured chromaticity has reached the target chromaticity (XW, YW) (S153), and is driven while measuring the chromaticity until the target chromaticity (XW, YW) is reached. The signal adjustment is repeated (S151 to S153).

10 and 11, the chromaticity measured by the chromaticity sensor 281 corresponding to the central area A5 is (X5, Y5). Therefore, when the process of step S152 is performed, XW and X5 And the difference between YW and Y5. And a drive signal is increased / decreased for every liquid crystal panel 23, 24, 25 so that this difference may become small. At this time, in each of the liquid crystal panels 23, 24, and 25, the chromaticity unevenness and the luminance unevenness have already been eliminated, so that the drive signals corresponding to the three regions A5, A1, and A9 are increased or decreased equally.

  Thus, as shown in FIG. 11C, the chromaticities corresponding to the three regions A5, A1, and A9 all become the target chromaticity (XW, YW). At this time, the intensity of each RBG light in the areas A5, A1, and A9 is equal to each other as shown in FIG. In addition, the broken line of FIG.10 (d) shows the brightness | luminance of R light, G light, and B light before chromaticity correction | amendment.

  Thus, the chromaticity corresponding to all the regions (strictly speaking, the arrangement position of the sensor unit 28) reaches the target chromaticity. In the present embodiment, the drive signal for the R light liquid crystal panel 23 is fixed, and chromaticity correction is performed for each region. That is, at the time of chromaticity correction, drive signals for the G light and B light liquid crystal panels 24 and 25 are adjusted. Alternatively, chromaticity correction may be performed by fixing a driving signal for a liquid panel other than the liquid crystal panel 23 for R light, or color may be corrected without fixing a driving signal for any liquid crystal panel. Degree correction may be performed.

  Thereafter, based on the adjustment result, the CPU 101 determines a correction coefficient γ (γR, γG, γB) of the drive signal related to chromaticity correction as shown in FIG. 12 (S154). The correction coefficient γ is different for each of the liquid crystal panels 23, 24, and 25, but is common to all the regions A1 to A9. The correction coefficient γ is obtained by the following equation.

  γ = drive signal after chromaticity unevenness correction for each area (position of sensor unit 28) of each liquid crystal panel / drive signal before chromaticity unevenness correction for each area (position of sensor unit 28) of each liquid crystal panel (3)

  The denominator on the right side of Equation (3) is a drive signal after the luminance unevenness correction shown in FIG. 10C is performed.

  As described above, since the correction coefficient γ is common to all the regions A1 to A9 of the liquid crystal panels 23, 24, and 25, the calculation of the expression (3) is performed on the region A1 of the liquid crystal panels 23, 24, and 25. Any one of -A9 may be performed. That is, the correction coefficient γ obtained based on the above equation (3) for any one of the regions A1 to A9 (for example, the region A5) is also applied to the other regions.

  In the present embodiment, the correction coefficients γR, γG, γB thus obtained are applied to the entire areas A1 to A9 of the liquid crystal panels 23, 24, 25.

  In the case where the chromaticity unevenness correction is performed by fixing the driving signal for the liquid crystal panel 23 for R light as described above, the correction coefficient γR corresponding to the R light is “1”.

  Returning to FIG. 7, the CPU 101 finally performs a luminance correction process (S16). That is, as shown in FIG. 8E, the CPU 101 first measures the luminance by the illuminance sensor 282 corresponding to the central area A5 (S161).

  The CPU 101 adjusts the gain of the video signal (RGB signal) for the test image 1 in the video signal processing circuit 105 so that the luminance measured by the central illuminance sensor 282 is equal to the target luminance Z1 (S162). . The CPU 101 determines whether or not the measured luminance has reached the target luminance Z1 (S163), and repeats the gain adjustment while measuring the luminance until it reaches the target luminance Z1 (S161 to S163).

  In the specific example of FIG. 10, when the process of step S142 is performed, the difference between the target luminance Z1 and the luminance measured by the central illuminance sensor 282 is obtained. Then, the gain of the video signal is increased / decreased in the video signal processing circuit 105 so that the difference becomes smaller. In each panel drive circuit 106, 107, 108, the drive signal is increased or decreased in accordance with the increase or decrease of the gain of the video signal.

  Thereby, as shown in FIG. 10E, the luminance corresponding to the areas A5, A1, and A9 becomes equal to the target luminance Z1. In addition, the broken line of FIG.10 (e) shows the brightness | luminance of R light, G light, and B light before chromaticity correction | amendment.

  Thus, when the brightness corresponding to all the areas reaches the target brightness Z1, the CPU 101 sets the gain of the video signal at that time as the correction coefficient δ. (S164: Refer to FIG. 10E).

  As described above, since the correction coefficient δ is common to all the regions A1 to A9 of all the liquid crystal panels 23, 24, 25, the setting of the video signal gain (correction coefficient δ) is set to the liquid crystal panels 23, 24, Any one of 25 predetermined areas (for example, area A5) may be performed. That is, the correction coefficient δ obtained for any one of the liquid crystal panels 23, 24, and 25 is the same for the other areas of the liquid crystal panel and all the areas A1 to A9 of the other liquid crystal panels. Applied.

  In the present embodiment, the correction coefficient δ obtained for the arrangement position of the sensor unit 28 is applied to the entire areas A1 to A9 of the liquid crystal panels 23, 24, and 25 corresponding to the sensor units 28. The correction coefficient δ is omitted from FIG. 12 for convenience because it is common to all the regions A1 to A9 of all the liquid crystal panels 23, 24, and 25.

  Returning to FIG. 7, when the luminance correction is completed and the image quality adjustment using the test image 1 is completed, the CPU 101 determines whether the image quality adjustment for all the test images is completed (S17). Here, since the image quality adjustment by the test image after the test image 2 has not been completed yet, the process returns to step S12. Then, the CPU 101 performs chromaticity unevenness correction, luminance unevenness correction, chromaticity correction, and luminance correction using the test image 2 as in the case of the test image 1 (S12 to S16). Thereby, the correction coefficients α, β, γ, and δ by the test image 2 are determined.

  Similarly, the CPU 101 sequentially performs image quality adjustment using the test image 3, the test image 4, and the test image 5. As a result, correction coefficients α, β, γ, and δ based on these test images are determined.

  When the image quality adjustment with all the test images is completed in this way (S17: YES), the CPU 101 sets the correction coefficients α, β, γ, and δ in association with each gradation (0 to 100%) of the video signal. A correction coefficient table is created (S18).

  FIG. 13A is a diagram schematically showing an example of the relationship between the correction coefficient and the gradation of the RGB signal. Plot points in the figure indicate correction coefficients (α, β, γ, δ) obtained from five test images.

Even when the liquid crystal panels 23, 24, and 25 are in the same deterioration state, if the modulation levels in the liquid crystal panels 23, 24, and 25 are different due to the different gradations of the input RGB signals, the luminance generated in the projected image The degree of decrease and the degree of change in chromaticity are different. For this reason, as shown in FIG. 13A, the values of the four correction coefficients α, β, γ, and δ vary according to the gradation level of the RGB signal. Note that, since the variation tendency of the correction coefficient varies from projector to projector due to individual differences of the liquid crystal panels, FIG. 13A does not show a fixed variation tendency of the correction coefficient, and the correction coefficient varies to the last. It is only what shows this typically.

  Therefore, the CPU 101 determines the values of the correction coefficients α, β, γ, and δ corresponding to each gradation (0 to 100%) based on the values of the five correction coefficients obtained from the five test images. For example, as shown in FIG. 13, five correction coefficient values are connected with a straight line, and a correction coefficient corresponding to a gradation between the two correction coefficients is determined from the slope of each straight line. The correction coefficient can be set for each gradation or with a width of several gradations. In this way, the CPU 101 completes the correction coefficient table for each of the correction coefficients α, β, γ, and δ.

  FIGS. 13B to 13E show examples of the correction coefficient table. FIGS. 7B to 7E show that when all the gradations of the video signal are 256 gradations (0 to 255), the correction coefficients α, β, γ, and δ are set with a width of 5 gradations. An example of a correction coefficient table is shown. Note that the correction coefficient tables of the correction coefficients α, β, and γ shown in (b), (c), and (d) of the same figure are created for each of the areas A1 to A9 of the liquid crystal panels 23, 24, and 25.

  Thus, the created correction coefficient tables of correction coefficients α, β, and γ are held in the panel drive circuits 106, 107, and 108. A correction coefficient table for the correction coefficient δ is held in the video signal processing circuit 105. Actually, by multiplying the three correction coefficients α, β, and γ, the correction coefficients related to the drive signals of the liquid crystal panels 23, 24, and 25 are combined into one, and the correction is combined into one. It is desirable that the correction coefficient table for the coefficient P is held in the panel drive circuits 106, 107 and 108.

  Finally, the CPU 101 sets the light shielding shutter 27 in an open state (S19), and ends the image quality adjustment mode.

  In the subsequent projection operation, the video signal processing circuit 105 adjusts the gain of the input video signal according to the correction coefficient δ. Subsequently, in each panel drive circuit 106, 107, 108, the drive signal based on the video signal is adjusted according to the correction coefficients α, β, γ (correction coefficient P), and the liquid crystal panels 23, 24, 25 is driven.

  As described above, according to the present embodiment, even when the lamp 21 and the liquid crystal panels 23, 24, and 25 are deteriorated due to aging, the image quality adjustment is automatically performed based on the correction coefficient set in the image quality adjustment mode. As a result, the image quality can be kept good.

  In particular, according to the present embodiment, the plurality of sensor units 28 (the chromaticity sensor 281 and the illuminance sensor 282) are arranged in a distributed manner on the light-shielding shutter 27. Therefore, the chromaticity measured by these sensor units 28 is used. Further, it is possible to eliminate chromaticity unevenness and luminance unevenness based on brightness and brightness, and to maintain better image quality.

  In addition, according to the above-described embodiment, image quality adjustment is performed using a plurality of test images having different luminances, and correction according to the gradation of the RGB signal is performed based on the correction coefficient obtained from each test image. A coefficient can be set. Thereby, it is possible to perform an appropriate image quality adjustment according to the gradation of the RGB signal using these correction coefficients.

  Further, according to the above embodiment, since the light shielding shutter 27 is arranged between the dichroic prism 26 and the projection lens 30, the image light before entering the projection lens 30 is detected by the sensor unit 28 (color The intensity sensor 281 and the illuminance sensor 282) are irradiated. Therefore, it is difficult for the image light to be attenuated or affected by light outside the apparatus, and chromaticity and luminance can be detected with high accuracy.

  Although the present embodiment has been described above, the present invention is not limited to the above embodiment, and the embodiment of the present invention can be variously modified in addition to the above embodiment. is there.

  For example, in the embodiment described above, the chromaticity is corrected in step S15 after correcting the chromaticity unevenness in step S13. However, based on the chromaticity measured by each chromaticity sensor 281, the CPU 101 controls each panel drive circuit 106, 107, so that the chromaticity corresponding to each of the areas A1 to A9 reaches the target chromaticity (XW, XY). The chromaticity unevenness correction and the chromaticity correction may be performed at a time by adjusting the drive signal 108.

  In the above embodiment, the video signal processing circuit 105 corrects the luminance by adjusting the gain of the video signal. However, the lamp output adjustment circuit 110 adjusts the luminance of the lamp 21. Thus, the luminance may be corrected.

  Further, in the above embodiment, the sensor unit 28 is configured by the chromaticity sensor 281 and the illuminance sensor 282. However, the present invention is not limited to this, and the sensor unit 28 may be configured by three photodiodes each having sensitivity to R light, G light, and B light. A corresponding detection signal is output. The CPU 101 obtains the chromaticity of the image light based on the ratio of the luminance of each RGB light input from the sensor unit 28, and obtains the luminance of the image light by adding the luminance of each RGB light.

  As described above, when the detection signal corresponding to the luminance of each RGB light is output from the sensor unit 28, the image quality adjustment mode may be changed as follows.

  That is, the data table shown in FIG. 14 is stored in the memory 102 instead of the data table shown in FIG. In the data table of FIG. 14, instead of the target chromaticity and target luminance of FIG. 6, the luminance value of each RGB light detected by the sensor unit 28 at the target chromaticity and target luminance is set as the target value. The

  In the image quality adjustment mode of this modified example, as shown in the processing flow of FIG. 15A, the image quality correction processing (S20) is performed in the chromaticity unevenness correction, luminance unevenness correction, chromaticity correction, and chromaticity correction of the processing flow of FIG. This is executed instead of the luminance correction (S13 to S16).

  The image quality correction process is shown in the process flow of FIG. First, the CPU 101 measures the luminance of each RGB light by each sensor unit (S201). Then, the CPU adjusts the drive signals of the panel drive circuits 106, 107, and 108 for each of the regions A1 to A9 so that the measured luminance of each RGB light reaches the target value (S202). If the luminance of each RGB light reaches the respective target value (S203: YES), all corrections for chromaticity unevenness, luminance unevenness, chromaticity and luminance are completed. Based on the adjustment result, the CPU 101 determines a drive signal correction coefficient S (SR1 to SR9, SG1 to SG9, SB1 to SB9) related to image quality correction for each region of each liquid crystal panel (S204). The correction coefficient S is different for each of the liquid crystal panels 23, 24, and 25, and is different for each of the regions A1 to A9. The correction coefficient S is obtained by the following equation.

  S = drive signal after image quality correction for each area (positioning position of sensor unit 28) of each liquid crystal panel / drive signal before image quality correction for each area (positioning position of sensor unit 28) of each liquid crystal panel (4)

  In the present modification example, the correction coefficients SR1 to SR9, SG1 to SG9, and SB1 to SB9 thus obtained with respect to the arrangement position of the sensor unit 28 are the regions A1 to A1 of the liquid crystal panels 23, 24, and 25 corresponding to the sensor units 28. Applies to A9 as a whole.

  If the image quality adjustment mode is changed to this change, chromaticity unevenness correction, luminance unevenness correction, chromaticity correction, and luminance correction are performed at one time, and only one correction coefficient S is set. In the case of this modification, the correction coefficient S corresponds to the chromaticity adjustment value and the luminance adjustment value of the present invention.

  In the above embodiment, the correction coefficients (α, β, γ, δ) obtained based on the detection signal from the sensor unit 28 are applied to the entire region corresponding to the sensor unit 28. However, the deterioration states of the liquid crystal panels 23, 24, and 25 are not all the same in each region, and are considered to approach the deterioration states of the surrounding regions as they move away from the position of the sensor unit 28 corresponding to that region.

  Therefore, as shown in FIG. 16A, the liquid crystal panels 23, 24, and 25 are divided more finely than the number of sensor units 28, and the areas A1 to A9 corresponding to the sensor units 28 are implemented as described above. The correction coefficient may be obtained in the same manner as in the embodiment, and the correction coefficients of other areas may be obtained based on the correction coefficients of the areas A1 to A9. In this case, as shown in FIG. 16B, an axis corresponding to the correction coefficient value of each of the areas A1 to A9 is virtually provided, and a plane connecting the vertices of the axis is virtually drawn. For example, the correction coefficient value of the region Q shown in FIG. 16B can be obtained as the height of the axis extending from the position of the region Q to the plane.

  In FIG. 16B, the plane of the peripheral portion outside the areas A1 to A9 is set as follows, for example. That is, the axis of the area A1 is set to the boundary position between the left and rear pixel areas of the area A1 and the left rear corner position of the pixel area. The axis of the area A3 is set to the boundary position of the pixel area on the right side and the rear side of the area A3 and the position of the right rear corner of the pixel area. The axis of the area A7 is set to the boundary position of the left and front pixel areas of the area A7 and the position of the left front corner of the pixel area. The axis of the area A9 is set to the boundary position between the right and front pixel areas of the area A9 and the left rear corner position of the pixel area. The axis of the area A2 is set to the boundary position behind the area A2. The axis of the area A4 is set to the left boundary position of the area A4. The axis of the region A6 is set to the right boundary position of the region A6. The axis of the area A8 is set to the boundary position in front of the area A8. By connecting the vertices of the axes set in this way, the plane of the peripheral portion outside the areas A1 to A9 is set as shown in FIG. The value of the correction coefficient for each region in the peripheral portion is obtained as the height of the axis extending from the position of each region to the plane thus set.

  Furthermore, in the above embodiment, nine sensor units 28 are arranged on the light shielding shutter 27, but the number of sensor units 28 is not limited to nine. For example, it may be 5 or 15.

  In the present embodiment, the light shielding shutter 27 is disposed between the dichroic prism 26 and the projection lens 30. However, the present invention is not limited to this, and the light shielding shutter 27 is disposed on the exit surface side of the projection lens 30. You can also However, in this case, it can be easily influenced by the attenuation of the image light or the light outside the machine.

  Further, the projector according to the present embodiment is a single-lamp projector, but may be a multi-lamp projector.

  In addition, the embodiment of the present invention can be variously modified as appropriate within the scope of the technical idea shown in the claims.

21 Lamp (light source)
23, 24, 25 Liquid crystal panel (light modulator)
27 Shading shutter (shutter)
28 Sensor unit (detector)
281 chromaticity sensor (chromaticity detection unit)
282 Illuminance sensor (luminance detector)
30 Projection lens (projection unit)
101 CPU (image quality adjustment unit)
105 Video signal processing circuit (image quality adjustment unit)
106, 107, 108 Panel drive circuit (image quality adjustment unit)
109 Lamp output adjustment circuit (image quality adjustment unit)

Claims (6)

In a projection display device that projects an image onto a projection surface,
A light source;
A light modulation unit that modulates light from the light source based on a video signal to generate video light;
A shutter that blocks or opens the optical path of the image light;
A plurality of detectors arranged in a distributed manner on the shutter and outputting detection signals corresponding to the image light irradiated on the shutter;
An image quality adjustment unit that adjusts an image quality of a projected image based on the detection signals from the plurality of detection units in a state where the image light is blocked by the shutter;
A projection-type display device comprising: The projection display device according to claim 1,
Each of the detection units includes a chromaticity detection unit that outputs a detection signal corresponding to the chromaticity of the video light,
The image quality adjustment unit acquires the detection signals from the chromaticity detection units in a state where the image light based on the test image with uniform chromaticity is irradiated on the shutter, and the detection signal of the acquired detection signals Setting a chromaticity adjustment value for adjusting the chromaticity of the projected image so that the difference is reduced;
A projection display device characterized by that. The projection display device according to claim 2,
The shutter is irradiated with the video light based on the plurality of test images having different luminances, and
The image quality adjustment unit acquires the chromaticity adjustment value for the corresponding luminance in each state where the image light based on each test image is irradiated, and based on the acquired each chromaticity adjustment value, Adjust chromaticity,
A projection display device characterized by that. The projection display device according to any one of claims 1 to 3,
Each of the detection units includes a luminance detection unit that outputs a detection signal corresponding to the luminance of the video light,
The image quality adjustment unit acquires the detection signal from each luminance detection unit in a state where the image light based on the test image with uniform luminance is applied to the shutter, and the difference between the acquired detection signals Setting a brightness adjustment value for adjusting the brightness of the projected image so that the
A projection display device characterized by that. The projection display device according to claim 4,
The shutter is irradiated with the video light based on the plurality of test images having different luminances, and
The image quality adjustment unit acquires the luminance adjustment value for the corresponding luminance in each state where the image light based on each test image is irradiated, and based on the acquired luminance adjustment value, the luminance of the projection image Adjust the
A projection display device characterized by that. The projection display device according to any one of claims 1 to 5,
A projection unit for enlarging and projecting the image light;
The shutter is disposed between the light modulation unit and the projection unit.
A projection display device characterized by that.

Images