WO2011092807A1 - Dispositif d'affichage de type à projection et son procédé de commande - Google Patents

Dispositif d'affichage de type à projection et son procédé de commande Download PDF

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Publication number
WO2011092807A1
WO2011092807A1 PCT/JP2010/051032 JP2010051032W WO2011092807A1 WO 2011092807 A1 WO2011092807 A1 WO 2011092807A1 JP 2010051032 W JP2010051032 W JP 2010051032W WO 2011092807 A1 WO2011092807 A1 WO 2011092807A1
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Prior art keywords
light
reference value
brightness
frame
luminance
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PCT/JP2010/051032
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English (en)
Japanese (ja)
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タン テイ ミョー
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Ｎｅｃディスプレイソリューションズ株式会社
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Priority to PCT/JP2010/051032 priority Critical patent/WO2011092807A1/fr
Publication of WO2011092807A1 publication Critical patent/WO2011092807A1/fr

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/208—Homogenising, shaping of the illumination light
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3102—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators
    • H04N9/3111—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying the colours sequentially, e.g. by using sequentially activated light sources
    • H04N9/3114—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying the colours sequentially, e.g. by using sequentially activated light sources by using a sequential colour filter producing one colour at a time
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3179—Video signal processing therefor
    • H04N9/3182—Colour adjustment, e.g. white balance, shading or gamut
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/005—Projectors using an electronic spatial light modulator but not peculiar thereto
    • G03B21/008—Projectors using an electronic spatial light modulator but not peculiar thereto using micromirror devices
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2066—Reflectors in illumination beam

Definitions

  • the present invention relates to a projection display device and a method for controlling the projection display device.
  • FIG. 1 is a block diagram showing a configuration example of a related projection display apparatus.
  • the projection display apparatus includes an optical engine 100 and a control unit 200.
  • the optical engine 100 includes a lamp 110 serving as a light source, a lens 120 that collects light from the lamp 110, a color wheel 140, a rod integrator 150, a reflective image forming element 130, and a reflective image forming element 130.
  • a projection lens 160 that projects the reflected light onto the screen and an absorber (absorber) 170 that absorbs the light that is not projected onto the screen are included.
  • the control unit 200 includes an image signal input unit 230, an image signal processing unit 210, and a color wheel driving circuit 250.
  • the image signal processing unit 210 includes a frame memory 211 and a scaling / gamma correction unit 215.
  • DMD digital micromirror device
  • the DMD element has a configuration in which hundreds of thousands or more of micromirrors are arranged in a matrix on a rectangular plane.
  • One pixel in one frame image corresponds to one micromirror.
  • the micromirror operates in either ON or OFF according to a video signal including an ON / OFF signal that is a signal for instructing ON or OFF, and changes the direction of the mirror depending on whether it is ON or OFF.
  • the light incident on the micro mirror that is turned on is reflected by the micro mirror and sent to the projection lens 160.
  • the light reflected by the ON-operation micromirror is collectively referred to as ON light.
  • the light incident on the micro mirror that is turned off is reflected by the micro mirror and sent to the absorber 170.
  • the light reflected by the micromirror that is turned off is collectively referred to as OFF light.
  • ON / OFF of the micromirror is modulated by a pulse width modulation method based on the ON / OFF signal of the video signal.
  • the color wheel 140 an area sandwiched between the outer periphery of the disk and a concentric circle on the center side of the disk is divided into three parts by a line passing through the central axis so that the center angle of the disk is equal. Each of the three divided parts is provided with a color filter for each of the three primary colors consisting of red (R), green (G), and blue (B).
  • the color wheel 140 rotates in accordance with the control of the color wheel driving circuit 250 and irradiates the rod integrator 150 with the white light from the lamp 110 divided into the three primary colors in terms of time.
  • the color of the filter provided on the color wheel 140 is three primary colors.
  • the color is not limited to the three primary colors, and may be four colors obtained by adding white to the three primary colors.
  • the rod integrator 150 is an optical element that irradiates the reflective image forming element 130 with light incident from the color wheel 140 in a uniform illuminance distribution.
  • the image signal input unit 230 is continuously input with a video signal that is a signal related to one frame of video, and a vertical synchronizing signal (Vsync) / horizontal synchronizing signal (Hsync) (in the figure, “ When a synchronization signal composed of “V / Hsync” is input, the input signal is decoded, converted from an analog signal to a digital signal, and the digitized signal is transmitted to the image signal processing unit 210.
  • Vsync vertical synchronizing signal
  • Hsync horizontal synchronizing signal
  • the scaling / gamma correction unit 215 is configured to correct an error in scaling and video brightness for matching the video size of the video signal to the size of the DMD element with respect to the video signal received from the image signal input unit 230.
  • a video signal that has been subjected to gamma correction is generated.
  • the video signal includes an ON / OFF signal corresponding to each of the three primary colors, and the pulse width of the ON / OFF signal corresponds to color information indicating the gradation information.
  • the scaling / gamma correction unit 215 transmits the generated video signal to the frame memory 211 one video at a time in synchronization with the synchronization signal.
  • the scaling / gamma correction unit 215 transmits a color filter synchronization signal indicating the color field switching timing of the color wheel 140 to the color wheel driving circuit 250 based on the vertical synchronization signal received from the image signal input unit 230.
  • the color field is a period in which the color wheel 140 is irradiated with light from one of the three primary colors in one frame period.
  • the color wheel driving circuit 250 rotates the color wheel 140 in accordance with the color filter synchronization signal received from the image signal processing unit 210.
  • the frame memory 211 temporarily stores a video signal of one frame received from the scaling / gamma correction unit 215, and turns on / off each micromirror according to the color information of the video signal, the vertical synchronization signal, and the horizontal synchronization signal. An OFF signal is transmitted to the reflective image forming element 130.
  • the image signal processing unit 210 converts the video signal into a video signal that matches the size and color of the image to be projected.
  • the micromirror ON / OFF signal corresponding to the signal is transmitted to the reflective image forming element 130 in accordance with the synchronization signal via the frame memory 211 for each frame.
  • the image signal processing unit 210 supplies a color filter synchronization signal to the color wheel driving circuit 250.
  • the color wheel driving circuit 250 controls the rotation of the color wheel 140 according to the color filter synchronization signal, so that the light of the white light source is temporally divided into three primary colors, and the reflective image forming element 130 is passed through the rod integrator 150. Is irradiated.
  • each micromirror When an ON / OFF signal is input from the image signal processing unit 210 to the reflective image forming element 130, each micromirror operates ON or OFF according to the ON / OFF signal.
  • the light irradiated to the reflective image forming element 130 the light reflected by the micromirror that is turned on is sent to the projection lens 160, and the light reflected by the micromirror that is turned off is absorbed by the absorber 170.
  • the light sent to the projection lens 160 is projected on the screen, and an image corresponding to the video signal is displayed on the screen.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2004-163876
  • Patent Document 2 Japanese Patent Application Laid-Open No. 2008-292953
  • Patent Document 3 Japanese Unexamined Patent Application Publication No. 2007-127856
  • Patent Document 4 An example of a projection television that can use the OFF light is disclosed in Japanese Patent Laid-Open No. 2002-287250 ( Hereinafter, it is disclosed in Patent Document 4).
  • Patent Document 4 defines an average ON rate that indicates an average ratio of ON light in one frame, and discloses a graph that indicates the relationship between the intensity of light irradiated on the light receiving plane 3 and the average ON rate. . From this graph, it can be seen that the smaller the average ON rate, the greater the intensity of the light that reciprocates the OFF light and joins the light of the light source.
  • Patent Document 4 adopts a CRT television technology that limits the luminance of a high average luminance image exceeding the normal luminance level, determines a predetermined value Q corresponding to the normal average luminance level, and determines the average ON rate. Is less than Q, the light intensity applied to the light receiving plane 3 is controlled to be constant, and when the average ON rate is greater than Q, the intensity of the light obtained by reciprocating the OFF light along the propagation path. Control to maximize
  • the OFF light that is not used in the projected image depends on the content of the projected image, and the luminance changes from frame to frame. Therefore, if the luminance difference between frames is large, the blinking (flickering) phenomenon becomes noticeable. . When the flickering phenomenon becomes prominent, flicker is perceived by a person viewing the image, and it is difficult to reuse OFF light as a light source.
  • the flickering phenomenon is not taken into consideration, and when the average ON rate is less than Q, even if the flickering phenomenon is suppressed, the average ON rate is larger than Q. May cause a noticeable flickering phenomenon, in which case the person viewing the image will perceive the flicker.
  • One of the objects of the present invention is to provide a projection display apparatus that suppresses the occurrence of flicker and can use OFF light that is not used for projection as light of a light source.
  • a projection display device includes a plurality of micromirrors arranged in a matrix that operates either on or off in response to a video signal indicating one frame of video, and illuminates the micromirror.
  • Reflective image forming element that forms a projected image by the reflected light reflected by the ON-operation micromirror, and the transmittance can be changed, and the OFF light that is reflected from the OFF-operation micromirror is transmitted.
  • Optics that illuminates the reflective image forming element as illumination light with uniform illuminance distribution, by making the transmission panel that emits the feedback light, the light source, and the light collected from the feedback light and the light from the light source.
  • the device includes a memory that stores a predetermined reference value as an initial value, and compares the absolute value of the difference in brightness of the OFF light between the current frame and the next frame with the reference value. Is larger than the reference value, the brightness of the OFF light of the next frame is obtained, and the transmittance of the transmissive panel is switched to obtain the feedback light of the obtained brightness, and in the next frame, the absolute value is smaller than the reference value.
  • a control unit that calculates a new reference value based on the feedback light and stores the new reference value in a memory.
  • a control method for a projection display apparatus includes a plurality of micromirrors arranged in a matrix that operates either ON or OFF in response to a video signal indicating one frame of video.
  • Reflective image forming element that forms a projection image with reflected light reflected by the micromirrors that are turned on for illumination light that illuminates the micromirrors, and the reflected light of the micromirrors that are turned off and configured to change the transmittance.
  • Reflection-type image formation as illumination light by making the transmissive panel that transmits OFF light and emitting it as feedback light, the light source, and the light collected from the feedback light and light from the light source, making the illuminance distribution uniform
  • a method for controlling a projection display apparatus having an optical element for irradiating an element and a memory for storing a reference value set in advance as an initial value, wherein the current frame and the next frame are turned off.
  • the transmittance of the transmissive panel is switched, a new reference value is calculated based on the feedback light in the next frame, and the new reference value is stored in the memory.
  • FIG. 1 is a block diagram showing a configuration example of a related projection display apparatus.
  • FIG. 2 is a block diagram illustrating a configuration example of the projection display apparatus according to the first embodiment.
  • FIG. 3 is a view for explaining the operation of the optical engine shown in FIG.
  • FIG. 4 is a diagram for explaining a method of combining the light from the lamp and the OFF light.
  • FIG. 5 is a block diagram for explaining the configuration of the control unit shown in FIG.
  • FIG. 6 is a flowchart showing the procedure of the OFF light adjustment method for suppressing flicker.
  • FIG. 7 is a graph showing the utilization ratio of the primary light quantity.
  • FIG. 8 is a block diagram illustrating a configuration example of the projection display apparatus according to the second embodiment.
  • FIG. 9 is a diagram for explaining the configuration of the control unit shown in FIG.
  • FIG. 2 is a block diagram showing an example of the configuration of the projection display device of the present embodiment.
  • the same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
  • the projection display device of the present embodiment includes an optical engine 10 and a control unit 20.
  • the optical engine 10 includes a configuration obtained by removing the absorber 170 from the optical engine 100 illustrated in FIG. 1, an OFF light feedback unit 11, and a light merging unit 30.
  • the optical confluence unit 30 includes reflection mirrors 31 and 32 and a condensing lens 35.
  • the OFF light feedback unit 11 includes a condenser lens 12 that condenses the OFF light, a transmissive liquid crystal panel 14, and an optical fiber 13 that guides the light focused by the condenser lens 12 to the liquid crystal panel 14.
  • the optical path until the OFF light reflected by the reflective image forming element 130 reaches the light combining unit 30 via the OFF light feedback unit 11 corresponds to a feedback path for returning the OFF light to the light source side.
  • a cooling mechanism for absorbing heat may be provided in the optical fiber 13 and the liquid crystal panel 14 when heat is released when the intensity of OFF light attenuates in the return path.
  • the cooling mechanism is not shown in the drawing.
  • the control unit 20 includes an image signal input unit 230, an image signal processing unit 21, a color wheel drive circuit 25, and a liquid crystal panel control unit 27.
  • the image signal processing unit 21 includes a current image frame memory 212, a next image frame memory 213, and a scaling / gamma correction unit 215.
  • the image signal input unit 230 is connected to the scaling / gamma correction unit 215 of the image signal processing unit 21 through a signal line.
  • the scaling / gamma correction unit 215 is connected to the color wheel driving circuit 25 through a signal line.
  • the liquid crystal panel control unit 27 is connected to each of the liquid crystal panel 14, the current image frame memory 212 and the next image frame memory 213 of the image signal processing unit 21, and the color wheel driving circuit 25 via signal lines.
  • the color wheel drive circuit 25 controls the rotation of the color wheel 140 according to the color filter synchronization signal received from the scaling / gamma correction unit 215 and transfers the color filter synchronization signal to the liquid crystal panel control unit 27.
  • a power supply circuit (not shown) for supplying power to the lamp 110 and the control unit 20 is not directly related to the features of the present invention, and thus description thereof is omitted.
  • the OFF light is used as the light of the secondary light source.
  • FIG. 3 is a block diagram for explaining the operation of the optical engine shown in FIG. 2, and FIG. 4 is a diagram for explaining a method of joining the light from the lamp and the OFF light.
  • the reflection mirror 31 is disposed at a position where the OFF light transmitted through the liquid crystal panel 14 of the optical engine 10 is incident.
  • the light after the OFF light has transmitted through the liquid crystal panel 14 is referred to as feedback light.
  • the mirror surface of the reflection mirror 31 is inclined by about 45 degrees with respect to the optical axis of the return light, reflects the return light and irradiates the condenser lens 35.
  • the reflection mirror 32 is disposed at a position where light emitted from the lamp 110 and focused by the lens 120 is incident.
  • the mirror surface of the reflection mirror 32 is inclined about 45 degrees with respect to the optical axis of the light from the lens 120, and reflects incident light to irradiate the condenser lens 35.
  • the condenser lens 35 is disposed between the reflection mirror 31 and the reflection mirror 32 and the color wheel 140, and collects the light reflected by the reflection mirror 31 and the light reflected by the reflection mirror 32 to the color wheel 140. Irradiate.
  • the return light reaches the reflection mirror 31 via the condenser lens 12, the optical fiber 13 and the liquid crystal panel 14.
  • the light emitted from the lamp 110 and collected by the lens 120 reaches the reflection mirror 32.
  • the optical axes of the light from the lamp 110 and the feedback light are adjusted in parallel by the reflecting mirror 31 and the reflecting mirror 32, and these lights are converged by being joined by the condenser lens 35.
  • the color wheel 140 is irradiated as light from one light source.
  • the condensing lens 12 is provided instead of the absorber 170 shown in FIG. 1, and the OFF light focused by the condensing lens 12 is guided to the liquid crystal panel 14 by the optical fiber 13.
  • the feedback light after passing through 14 is combined with the light from the lamp 110 via the reflection mirror 31 and the condenser lens 35 and irradiated to the color wheel 140.
  • the luminance of the OFF light is the content of the image to be projected or It varies greatly depending on the ON / OFF status of the micromirror. For example, when the brightest all-white screen is projected, there is no OFF light. Conversely, when the all-black screen is projected, all the light supplied from the lamp 110 is OFF light. Since the brightness of the OFF light varies greatly depending on the projected image, it is necessary to appropriately adjust the amount of OFF light to be returned.
  • the control unit 20 adjusts the amount of the return light in accordance with the timing of the color filter synchronization signal based on the brightness of the OFF light of two consecutive frames.
  • the configuration of the control unit 20 for using OFF light having different luminance for each frame as stable light will be described in detail.
  • the same control is performed for each of the three primary colors.
  • the case of one color will be described.
  • FIG. 5 is a block diagram for explaining the configuration of the control unit shown in FIG.
  • the current image frame memory 212 shown in FIG. 5 corresponds to the frame memory 211 shown in FIG. 1, and the image signal processing unit 21 has a configuration in which a next image frame memory 213 is added to the image signal processing unit 210 shown in FIG. It is.
  • the video signal of the current frame image that is the image of the frame to be projected is stored in the current image frame memory 212, and the video signal of the next frame image that is the image of the frame to be projected next is the next image frame memory 213.
  • the ON / OFF signal based on the video signal of the current frame image is transmitted to the reflective image forming element 130, the video signal of the next frame image is overwritten in the current image frame memory 212, and the video signal of the next frame is further transferred to the next frame.
  • the image frame memory 213 is overwritten.
  • the liquid crystal panel control unit 27 includes a luminance comparison unit 271 that compares the OFF light luminances of two consecutive frames, and a synchronization / adjustment circuit 272 that controls luminance adjustment and luminance adjustment timing.
  • a memory 273 that stores a reference value for determining whether or not to perform brightness adjustment, a decoder 274 that supplies a synchronization signal to the synchronization / adjustment circuit 272, and a liquid crystal drive circuit 275 that controls the transmittance of the liquid crystal panel 14.
  • the memory 273 is a nonvolatile memory.
  • the memory 273 calculates the luminance for determining the luminance of the feedback light based on the reference value as a criterion for determining whether or not to adjust the luminance of the OFF light to be fed back, and the luminance difference between the OFF lights of two consecutive frames.
  • the formula, the transmittance calculation formula indicating the relationship between the brightness of the feedback light and the transmittance of the liquid crystal panel 14, and the reference value calculation formula for obtaining the reference value corresponding to the brightness of the feedback light are registered in advance. .
  • the reference value serving as a criterion for determining whether or not to adjust the brightness of the OFF light is a limit brightness difference that humans can recognize as flicker, and a brightness difference smaller than the reference value is not recognized as flicker by humans.
  • This reference value is a limit value at which the human eye starts to perceive blinking due to a luminance difference that occurs every frame period (for example, 16.67 ms when the frame frequency is 60 Hz) as “flickering”. According to the Ferry-Porter law, it varies depending on the luminance of the target.
  • the visual target is a projected image.
  • the critical fusion frequency (CFF) which is the limit frequency at which a person can detect flicker
  • the CFF increases as the luminance increases, and the CFF decreases as the luminance decreases. From this, the relationship between the luminance and the reference value is as follows. As the luminance increases, the flicker becomes conspicuous and the reference value decreases. On the other hand, when the luminance is reduced, the flicker is less noticeable and the reference value is increased.
  • the reference value calculation formula described above is a formula for obtaining the reference value from the brightness of the feedback light based on the relationship between the brightness and the reference value.
  • the luminance calculation formula registered in advance in the memory 273 will be described later.
  • the luminance comparison unit 271 shown in FIG. 5 includes a decoder (not shown) and a comparator (not shown).
  • the decoder converts the video signal stored in each of the current image frame memory 212 and the next image frame memory 213 into a value indicating the brightness of the OFF light as follows. Based on the relationship that the brightness of the OFF light is proportional to the number of micromirrors that are turned off during one frame period, an equation for obtaining the brightness of the OFF light from the number of micromirrors that are turned off is stored in advance in the decoder circuit.
  • the decoder reads out the number of micromirrors operating OFF from the video signal for one frame, and calculates the brightness of the OFF light based on the number.
  • a comparator (not shown) of the luminance comparison unit 271 compares the luminances of the two OFF lights calculated by the decoder, and calculates the absolute value of the luminance difference between the two OFF lights. Then, the comparator transmits luminance information including information on the luminance of OFF light of each of the two consecutive frames and information on the absolute value of the luminance difference between the two OFF lights to the synchronization / adjustment circuit 272.
  • the decoder 274 When the decoder 274 receives the color filter synchronization signal from the color wheel driving circuit 25, the decoder 274 transmits a color filter synchronization signal for notifying the timing of the color field of the color to be adjusted to the synchronization / adjustment circuit 272.
  • the control signal including the transmittance information in accordance with the color filter synchronization signal is transmitted to the liquid crystal panel 14 to switch the transmittance of the liquid crystal panel 14.
  • the color filter synchronization signal is information indicating the timing of changing to the transmittance included in the adjustment signal.
  • FIG. 6 is a flowchart showing a procedure of an OFF light adjustment method for suppressing flicker.
  • the procedure described here is also performed for each of the three primary colors. However, since the description is redundant, the description will be given for the case of one color.
  • a reference value serving as a criterion for determining whether or not to adjust the OFF light luminance is T, the OFF light luminance of the current frame is P, and the OFF light luminance of the next frame is N.
  • the luminance information includes information of
  • the synchronization / adjustment circuit 272 When the synchronization / adjustment circuit 272 receives the brightness information from the brightness comparison unit 271, the synchronization / adjustment circuit 272 reads T from the memory 273 and compares
  • step 1001 if the absolute value of the difference between P and N is equal to or greater than the T value, the synchronization / adjustment circuit 272 compares the magnitudes of P and N (step 1003).
  • P is smaller than N, it is necessary to reduce the transmittance of OFF light in the liquid crystal panel 14 in order to make the absolute value of the difference between P and N smaller than the reference value.
  • the synchronization / adjustment circuit 272 refers to the luminance calculation formula registered in the memory 273 in order to make the absolute value of the difference between P and N smaller than the reference value, and the absolute value of the difference between P and N is the reference value.
  • the synchronization / adjustment circuit 272 obtains the transmittance of the liquid crystal panel 14 corresponding to the obtained luminance based on the transmittance calculation formula registered in the memory 273 and an adjustment signal including information on the obtained transmittance. Is transmitted to the liquid crystal driving circuit 275 (step 1004).
  • the synchronization / adjustment circuit 272 obtains a reference value for the luminance of the feedback light of the next frame from the reference value calculation formula, and registers the new reference value in the memory 273 to update the reference value.
  • the reference value is updated because the brightness of the feedback light changes as the transmittance of the liquid crystal panel 14 changes. Therefore, the reference value calculation formula based on the Ferry-Porter law based on the brightness after the change of the feedback light This is because it is necessary to re-determine a reference value that satisfies the above.
  • the reference value is changed according to the brightness after the change of the feedback light, so that the OFF light is maximized against the change in the brightness of the feedback light of the images projected one after another. And the occurrence of flicker can be suppressed.
  • the synchronization / adjustment circuit 272 refers to the luminance calculation formula registered in the memory 273 in order to make the absolute value of the difference between P and N smaller than the reference value, and the absolute value of the difference between P and N is the reference value. The minimum brightness of N that is less than. Subsequently, the synchronization / adjustment circuit 272 obtains the transmittance of the liquid crystal panel 14 corresponding to the obtained luminance based on the transmittance calculation formula registered in the memory 273 and an adjustment signal including information on the obtained transmittance. Is transmitted to the liquid crystal driving circuit 275 (step 1005).
  • the synchronization / adjustment circuit 272 obtains a reference value for the luminance of the feedback light of the next frame from the reference value calculation formula, and registers the new reference value in the memory 273 to update the reference value.
  • the synchronization / adjustment circuit 272 transmits the color filter synchronization signal received from the decoder 274 to the liquid crystal drive circuit 275.
  • the color filter synchronization signal as a switching timing for changing the transmittance of the liquid crystal panel 14, the transmittance of each color is adjusted to correspond to the period of the color field of each color.
  • L is an amount corresponding to the invariable loss in the return path including the optical fiber 13, the liquid crystal panel 14, and the reflection mirror 31.
  • the constant loss of the return path can be suppressed to 20% or less.
  • a (t) is the amount corresponding to the variable loss due to the luminance adjustment of the synchronization / adjustment circuit 272, and is the amount of light shielded by the liquid crystal panel 14.
  • a (t) is a parameter that is determined by the reference value calculation formula and changes for each frame.
  • a (t) is expressed as a function of time t because the frame changes at a constant period.
  • the amount of OFF light in one frame is (1-S), and the value obtained by subtracting the amount lost in the feedback path from that value is ⁇ (1-S) -L ⁇ . If the light quantity of ⁇ (1-S) -L ⁇ is used as it is as the secondary light source, flicker may occur. Therefore, by subtracting A (t) from ⁇ (1-S) -L ⁇ so that flicker does not occur, the amount of light F transmitted through the liquid crystal panel 14 becomes ⁇ (1-S) -LA (t). ⁇ .
  • a luminance calculation formula obtained by replacing the light quantity of the formula (2) with the luminance is registered in the memory 273 in advance.
  • the synchronization / adjustment circuit 272 obtains the transmittance of the liquid crystal panel 14 corresponding to the brightness obtained from the brightness calculation formula from the transmittance calculation formula, and information on the transmittance Is sent to the liquid crystal drive circuit 275.
  • FIG. 7 is a graph showing the utilization ratio of the primary light quantity, and is a graph visually representing the expression (2).
  • the initial reference value T may be an arbitrary value, but when the brightness of the feedback light and the brightness of the ON light coincide with each other, the value obtained from the reference value calculation formula is set as the initial T value. It is written as a point.
  • the primary light quantity is classified into four types: ON light, feedback light, variable loss due to brightness adjustment, and invariant loss due to the feedback path.
  • FIG. 7 shows that A (t) increases so that the brightness difference does not become larger than the reference value because the brightness due to the OFF light increases as the amount of OFF light increases.
  • the transmittance of the liquid crystal panel 14 in accordance with the increase or decrease in the brightness difference of the OFF light between two consecutive frames, the amount of the OFF light that is used as the light source.
  • the luminance change is maintained within the reference value.
  • the reference value is updated to a value corresponding to the brightness of the feedback light of the next frame.
  • the initial reference value registered in advance in the memory 273 is a value obtained from the reference value calculation formula when the luminances of the ON light and the feedback light match. Further, the case of one color among the three primary colors will be described.
  • the user connects an information processing apparatus (not shown) storing image data to be projected onto the screen to the projection display apparatus of the present embodiment with a cable. Subsequently, when the user activates the information processing apparatus and the projection display apparatus and turns on the power of the lamp 110, the light from the lamp 110 enters the condenser lens 35 via the lens 120 and the reflection mirror 32. The light condensed by the condenser lens 35 enters the reflective image forming element 130 via the color wheel 140 and the rod integrator 150.
  • a synchronization signal and a video signal of the image data are transmitted from the information processing apparatus to the image of the projection display apparatus.
  • the signal is input to the signal input unit 230.
  • the image signal processing unit 21 receives the first frame (hereinafter referred to as the current frame) and the next frame (hereinafter referred to as the next frame). ) Are stored in the current image frame memory 212 and the next image frame memory 213, respectively.
  • the image signal processing unit 21 transmits an ON / OFF signal based on the video signal stored in the current image frame memory 212 to the reflective image forming element 130 in accordance with the synchronization signal, so that the reflective image forming element 130 is transmitted.
  • An image based on the video signal of the current frame by the ON light from is projected onto the screen, and the OFF light is projected onto the condenser lens 12.
  • the liquid crystal panel control unit 27 adjusts the brightness of the OFF light from the respective video signals of the current image frame memory 212 and the next image frame memory 213 while an image based on the video signal stored in the current image frame memory 212 is being projected. calculate. Further, the liquid crystal panel control unit 27 calculates the absolute value of the difference in luminance of OFF light between two successive frames of the current frame and the next frame. Subsequently, the liquid crystal panel control unit 27 determines whether it is necessary to adjust the brightness of the OFF light of the next frame in accordance with the procedure shown in FIG.
  • the liquid crystal panel control unit 27 determines that the brightness of the OFF light of the next frame needs to be adjusted, the absolute value of the difference in the brightness of the OFF light of the two consecutive frames is smaller than the reference value, and the next frame is turned off. The luminance of light is obtained, and the transmittance of the liquid crystal panel 14 for obtaining feedback light of that luminance is obtained. Subsequently, the liquid crystal panel control unit 27 uses the color filter synchronization signal to match the start timing of the color field of the color filter of the color wheel 140 corresponding to the color information of the video signal of the next frame image. Is switched to the obtained transmittance. Thereafter, the liquid crystal panel control unit 27 obtains a reference value corresponding to the feedback light of the next frame and registers it in the memory 273.
  • the light obtained by combining the return light and the light from the lamp 110 enters the reflective image forming element 130 via the color wheel 140 and the rod integrator 150, and is used for projection of the next frame image switched from the current frame image.
  • the pulse time of the ON operation of the micromirror is about several tens of ⁇ s in the case of 256 gradations. Further, the time required for the OFF light reflected by the reflective image forming element 130 to return to the reflective image forming element 130 again through the return path is several considering the general size and speed of light of the projection display device. It is about ns.
  • OFF light generated in the time of several tens of ⁇ s from the start of projection of the next frame image is irradiated to the reflective image forming element 130 via the feedback path in several ns, for example, one frame period of 16.67 ms is This is a sufficient time to use the OFF light as a secondary light source for projecting an image using a video signal of the same frame as the frame that generates the OFF light.
  • step 1004 and step 1005 of the flowchart shown in FIG. 6 will be described in detail.
  • step 1003 when the brightness of the OFF light of the current frame is smaller than the OFF light of the next frame, the next frame image projected on the screen becomes an image darker than the current frame image.
  • the next frame image When the next frame image is projected, the brightness of the OFF light becomes larger than that in the case of the current frame image.
  • the liquid crystal panel control unit 27 reduces the transmittance of the liquid crystal panel 14 (step 1004), so that the second order The brightness of the light source is suppressed, and the person viewing the projected image on the screen does not feel flicker.
  • the next frame image projected on the screen becomes an image brighter than the current frame image.
  • the liquid crystal panel control unit 27 increases the transmittance of the liquid crystal panel 14 (step 1005), so that the second order The brightness of the light source increases, and the person viewing the projected image on the screen does not feel flicker.
  • the luminance comparison unit 271, the synchronization / adjustment circuit 272, and the liquid crystal driving circuit 275 perform the color filter synchronization signal based on the color information of the video signal.
  • the transmittance of the liquid crystal panel 14 is adjusted at the timing of the color field of the color to be adjusted.
  • the projection display apparatus effectively reuses the OFF light that is not used when the image is modulated by the DMD element as the secondary light source, compared with the case where the OFF light is not used.
  • the light use efficiency of the projector can be improved and a bright image can be provided.
  • the light obtained by returning the OFF light as a secondary light source has an effect of improving the brightness of the projected image. If the brightness of the primary light source is lowered by that amount, the life of the primary light source is further increased. The length can be increased, and the power consumption can be substantially reduced. For this reason, it is possible to increase the brightness of the projected image and to save energy in the power supplied to the projection display device.
  • the DLP projection display apparatus it has been considered extremely difficult to use OFF light whose luminance changes from frame to frame.
  • the OFF light is turned off. It is expected that the light use efficiency will be about 1.5 times that in the case where light is not used.
  • the light usage efficiency is expected to be about 1.5 times. Assuming that the light incident on the DMD element is 100%, when the OFF light is not used, the light that is effectively used is only 50%, and the remaining 50% is lost as the OFF light. In this embodiment, if the remaining 80% obtained by subtracting 20% of the constant loss from 100% is used to the maximum, the light utilization efficiency is about 1.6 times from the calculation result of 0.5 ⁇ 0.8. Can be estimated. In consideration of the variable loss at the time of adjustment for suppressing the flickering phenomenon in this estimated value, the light use efficiency is expected to be about 1.5 times.
  • the power of the lamp is controlled in accordance with the change in the brightness of the OFF light.
  • FIG. 8 is a block diagram showing an example of the configuration of the projection display device of the present embodiment.
  • symbol is attached
  • the control unit 20a of the projection display device according to the present embodiment is provided with a panel / lamp control unit 51 instead of the liquid crystal panel control unit 27 of the projection display device according to the first embodiment.
  • the lamp driving circuit 52 is further added.
  • the panel / lamp controller 51 is connected to the lamp driving circuit 52 through a signal line.
  • FIG. 9 is a diagram for explaining the configuration of the control unit shown in FIG.
  • each lamp type corresponds to the brightness difference of OFF light of two consecutive frames.
  • a power calculation formula for determining supply power is registered in the memory 273 in advance.
  • the synchronization / adjustment circuit 272 operates in the same manner as in the first embodiment, obtains power supplied to the lamp based on a preset lamp power calculation formula, and includes power information including information on power supplied to the lamp.
  • the color filter synchronization signal is transmitted to the lamp driving circuit 52.
  • the lamp driving circuit 52 When the lamp driving circuit 52 receives the color filter synchronization signal and the power information from the panel / lamp control unit 51, the lamp driving circuit 52 determines the power to the lamp 110 according to the power information, and matches the determined power with the color field of the color filter synchronization signal. Supplied to the lamp 110.
  • the power supplied to the lamp is controlled according to the type of the lamp as the brightness of the OFF light changes, so that the life of the primary light source is further improved and the power is saved. Promoted.
  • the projection display apparatus provided with the reflective image forming elements 130 corresponding to the three primary colors.
  • the present invention may be applied.
  • filters corresponding to the three primary colors may be provided in the respective reflective image forming elements 130. Since an example of an apparatus similar to a projection display apparatus provided with reflective image forming elements corresponding to the three primary colors is disclosed in Patent Document 4, detailed description thereof is omitted here.
  • the method using the OFF light feedback unit 11 and the light confluence unit 30 has been described.
  • the OFF light feedback unit 11 and the optical merging unit 30 are an example of the method, and other methods may be used.
  • the video signal input from the outside is an analog signal
  • it may be a digital signal.
  • the image signal input unit 230 may not be provided with a function for converting an analog signal into a digital signal.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Projection Apparatus (AREA)

Abstract

La présente invention concerne un dispositif d'affichage de type à projection comprenant un élément de formation d'image de type à réflexion (130) comprenant une pluralité de micromiroirs actifs ou inactifs en fonction du signal vidéo dans une trame, réfléchissant l'éclairage provenant des micromiroirs actifs et formant une image de projection ; un écran de type à transmission (14) conçu pour présenter une transmissivité variable, transmettant une lumière inactive provenant des micromiroirs inactifs et émettant ladite lumière inactive à titre de lumière de retour ; une source de lumière (110) ; un élément optique (150) qui propage sur l'élément de formation d'image de type à réflexion (130) une répartition homogène de la lumière qui résulte de la focalisation de la lumière de retour et de la lumière provenant de la source de lumière ; et une unité de commande (20) qui mémorise une valeur standard prédéfinie à titre de valeur initiale, compare la valeur standard à la valeur absolue de la différence de la luminance de la lumière inactive dans la trame actuelle et dans la trame suivante, détermine la luminance de la lumière inactive dans la trame suivante afin que la valeur absolue devienne inférieure à la valeur standard si la valeur absolue est supérieure à la valeur standard et afin d'obtenir une lumière de retour ayant la luminance déterminée, modifie la transmissivité de l'écran de type à transmission (14) et actualise la valeur standard à une valeur basée sur la lumière de retour dans la trame suivante.
PCT/JP2010/051032 2010-01-27 2010-01-27 Dispositif d'affichage de type à projection et son procédé de commande WO2011092807A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013140589A1 (fr) * 2012-03-23 2013-09-26 Ｎｅｃディスプレイソリューションズ株式会社 Appareil de source de lumière, appareil d'affichage par projection et procédé d'éclairage method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1082959A (ja) * 1996-09-09 1998-03-31 Sanyo Electric Co Ltd 投写型映像表示装置
JP2000171737A (ja) * 1998-12-04 2000-06-23 Matsushita Electric Ind Co Ltd プロジェクタ装置
JP2003121784A (ja) * 2001-10-18 2003-04-23 Mitsubishi Electric Corp 投写装置
JP2004138986A (ja) * 2001-11-08 2004-05-13 Seiko Epson Corp プロジェクタ
WO2009034694A1 (fr) * 2007-09-14 2009-03-19 Panasonic Corporation Projecteur

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1082959A (ja) * 1996-09-09 1998-03-31 Sanyo Electric Co Ltd 投写型映像表示装置
JP2000171737A (ja) * 1998-12-04 2000-06-23 Matsushita Electric Ind Co Ltd プロジェクタ装置
JP2003121784A (ja) * 2001-10-18 2003-04-23 Mitsubishi Electric Corp 投写装置
JP2004138986A (ja) * 2001-11-08 2004-05-13 Seiko Epson Corp プロジェクタ
WO2009034694A1 (fr) * 2007-09-14 2009-03-19 Panasonic Corporation Projecteur

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013140589A1 (fr) * 2012-03-23 2013-09-26 Ｎｅｃディスプレイソリューションズ株式会社 Appareil de source de lumière, appareil d'affichage par projection et procédé d'éclairage method
JPWO2013140589A1 (ja) * 2012-03-23 2015-08-03 Ｎｅｃディスプレイソリューションズ株式会社 光源装置、投写型表示装置及び照明方法

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