WO2008047856A1 - Appareil de projection d'image - Google Patents

Appareil de projection d'image Download PDF

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Publication number
WO2008047856A1
WO2008047856A1 PCT/JP2007/070329 JP2007070329W WO2008047856A1 WO 2008047856 A1 WO2008047856 A1 WO 2008047856A1 JP 2007070329 W JP2007070329 W JP 2007070329W WO 2008047856 A1 WO2008047856 A1 WO 2008047856A1
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WO
WIPO (PCT)
Prior art keywords
control mode
color
light source
light
image
Prior art date
Application number
PCT/JP2007/070329
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English (en)
Japanese (ja)
Inventor
Naoaki Tani
Original Assignee
Olympus Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Olympus Corporation filed Critical Olympus Corporation
Publication of WO2008047856A1 publication Critical patent/WO2008047856A1/fr

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Classifications

    • 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
    • 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
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2033—LED or laser light sources

Definitions

  • the present invention relates to an image projection apparatus.
  • an image projection apparatus such as a projector
  • a method of adjusting the brightness of a projected image a method of controlling the magnitude of a drive current applied to a light source and a pulsed drive current applied to the light source
  • a method for controlling the duty ratio is known.
  • Patent Document 1 Japanese Patent Laid-Open No. 2005-70443
  • the present invention has been made in view of the above-described circumstances, and it is an object of the present invention to provide an image projection apparatus capable of effectively reducing power consumption while suppressing a change in color of a projection image.
  • a first aspect of the present invention modulates illumination light emitted from the light source unit based on a light source unit having a plurality of light sources that generate illumination light of different colors and an input video signal.
  • a second control mode for variably controlling the duty ratio of the current detecting a feature amount of the display image from the video signal corresponding to one or a plurality of frames, and based on the feature amount! / Select one of the control mode and the second control mode! /, Or either of them, or both, and perform image projection to control drive of the light source in the selected control mode Providing equipment.
  • each light source of the light source unit is in a control mode corresponding to the feature amount of the video signal, specifically, a first control mode in which the light amount is adjusted by variably controlling the magnitude of the light source drive current,
  • drive control is performed in one of the second control modes in which the light amount is adjusted by variably controlling the duty ratio of the drive current of the light source, or in a control mode in which both are combined. Therefore, the light quantity of each light source can be adjusted by an appropriate control mode corresponding to the feature amount of the display image.
  • control unit may detect the feature amount for each color of the illumination light and select a control mode for each color of the illumination light.
  • the feature amount of the display image is detected for each color, and the light source of each color is driven and controlled in the control mode selected according to the feature amount according to the feature amount. Therefore, the amount of light can be adjusted according to an appropriate control mode for each color.
  • the control unit detects luminance as a feature amount of the display image, selects the second control mode when the luminance is equal to or higher than a predetermined value, and the luminance is predetermined.
  • the first control mode may be selected when the value is less than the value of.
  • the second control mode in which the magnitude of the drive current is not changed is selected. Power to avoid S
  • the power consumption can be reduced while allowing a slight color change by selecting the second control mode.
  • the control unit detects the brightness of the image for each color of the illumination light, and when the luminance is equal to or higher than a predetermined value, the control unit detects the light source corresponding to the color.
  • the light source corresponding to the color may be drive controlled in the first control mode.
  • the brightness of the display image is detected for each color, and the light source control mode corresponding to each color is selected depending on whether this brightness is a predetermined value or more.
  • the drive control of the light source can be performed.
  • control unit may detect a bias of a color component as the feature amount of the image and may select a control mode according to the bias of the color component.
  • the deviation of the color component since the deviation of the color component is detected as the feature amount of the image and the control mode is selected according to the deviation of the color component, the deviation of the color component can be reflected in the drive control of the light source. it can.
  • driving the light sources in the second control mode controls the color tone rather than reducing power consumption.
  • each light source when displaying an image with a color component bias that does not cause a significant change in color tone, each light source is driven and controlled in the first control mode, allowing a slight color tone change. Effectively reduce power consumption.
  • the control unit converts the color of the illumination light having a color change due to increase / decrease in drive current larger than a predetermined value as the color component of the display image to the other illumination light.
  • at least the light source corresponding to the color may be dynamically controlled in the second control mode '.
  • a change in color tone due to increase / decrease in drive current is greater than a predetermined value.
  • a small amount is displayed.
  • changes in color tone can be prevented by selecting the second control mode that does not increase or decrease the drive current.
  • the power consumption can be reduced by selecting the first control mode.
  • all light sources are set in the first control mode.
  • Drive control may be performed.
  • the power consumption can be effectively reduced while allowing a slight change in color tone.
  • control unit may detect the number of colors in the image and select a control mode according to the number of colors! /.
  • the number of colors is detected as the feature quantity of the image, and the control mode is selected according to the number of colors, so that the number of colors can be reflected in the drive control of the light source. For example, color change When displaying an image with a number of colors that appears prominently, color control is more important than power consumption reduction by driving and controlling each light source in the second control mode. On the other hand, when displaying an image with the number of colors such that the color tone does not change significantly, the power consumption is controlled while driving the light sources in the first control mode while allowing some color change. The power S is used to further reduce the power consumption.
  • control unit may drive and control all of the light sources in the first control mode when the number of colors in the image is less than a predetermined number! /.
  • a second aspect of the present invention modulates illumination light emitted from the light source unit based on a light source unit having a plurality of light sources that generate illumination light of different colors and an input video signal.
  • a first control mode for variably controlling the magnitude of the drive current applied to each of the light sources, and a control unit for driving and controlling each of the light sources of the light source unit.
  • a second control mode for variably controlling a duty ratio of a drive current applied to the light source, and a color change due to a change in the magnitude of the drive current is larger than a predetermined value.
  • the light source is driven in the second control mode.
  • There is provided an image projection apparatus that controls and controls the light source whose color change is equal to or less than a predetermined value in the first control mode.
  • the light source when an LED is used as the light source, there is a change in color tone due to an increase or decrease in drive current for an LED that emits red illumination light or an LED that emits blue illumination light. Since it is smaller than the fixed value, the light amount is adjusted in the first control mode. For LEDs that emit green illumination light, the color change due to increase or decrease in drive current is greater than that of the other light sources, so the light intensity is adjusted in the second control mode.
  • the image projection device of the present invention it is possible to effectively reduce the power consumption while suppressing the change in the color of the projection image.
  • FIG. 1 is a side view showing a schematic configuration of an image projection apparatus according to an embodiment of the present invention.
  • FIG. 2 is a block diagram showing a schematic internal configuration of the image processing apparatus shown in FIG.
  • FIG. 3 is a diagram for explaining the operation of the gain adjustment circuit shown in FIG. 2.
  • FIG. 4 is a diagram for explaining the operation of the gain adjustment circuit shown in FIG. 2.
  • FIG. 5 is a diagram for explaining a first control mode.
  • FIG. 6 is a diagram for explaining a second control mode.
  • FIG. 7 is a graph showing the drive current / single light quantity characteristics and drive current power consumption characteristics of an LED.
  • FIG. 8 is a diagram showing a change in color tone when the drive current is increased or decreased.
  • FIG. 9 is a diagram for explaining light amount control of the image projection apparatus according to an embodiment of the present invention.
  • FIG. 10 is a diagram in which the color tone of each pixel of a display image formed based on a video signal is plotted in the xy space using the three primary colors of sRGB as a reference, and shows an example of a flower image.
  • FIG. 11 is a diagram in which the color tone of each pixel of a display image formed based on a video signal is plotted in the xy space with the three primary colors of sRGB as a reference, and shows an example of a sunset image.
  • FIG. 12 is a diagram in which the color tone of each pixel of a display image formed based on a video signal is plotted in the xy space using the three primary colors of sRGB as a reference, and is a diagram showing an example of a presentation image.
  • FIG. 13 is a diagram showing a first modification of the light source unit shown in FIG.
  • FIG. 14 is a diagram showing a second modification of the light source unit shown in FIG. It is a top view when seen from the emission end side of bright light.
  • FIG. 15 is a longitudinal sectional view of the light source unit shown in FIG.
  • FIG. 16 is a diagram for explaining the rotation state and light transmission efficiency of a rotating rod provided in the light source unit shown in FIG.
  • FIG. 17 is a diagram showing the magnitude relationship between the maximum current values of the drive currents of the LEDs of the respective colors provided in the light source unit according to the second modification.
  • FIG. 18 is a diagram showing an example of light amount control of LEDs of respective colors included in a light source unit according to a second modification.
  • FIG. 19 is a diagram showing an example of light amount control of LEDs of respective colors included in a light source unit according to a second modification.
  • FIG. 20 is a diagram showing the relationship between the angle of the rotating rod and the light transmission efficiency according to the second modification.
  • FIG. 21 is a diagram showing a schematic configuration of an image projection apparatus according to a third modification.
  • the image projection apparatus 1 includes a light source unit 2, a light guide unit 3 that guides illumination light emitted from the light source unit 2, and illumination guided by the light guide unit 3.
  • a transmissive liquid crystal display panel (light modulator) 4 that modulates light and a projection optical unit 5 that projects illumination light modulated by the transmissive liquid crystal display panel 4 onto a screen S are provided.
  • illustration of the polarizing plate and the like is omitted.
  • the light source unit 2 includes a plurality of light sources that emit illumination lights of different colors and a light combining element 6 that guides the illumination light emitted from each light source to a common optical path.
  • the light source includes an LED 2a that emits red illumination light, an LED 2b that emits green illumination light, and an LED 2c that emits blue illumination light.
  • the light guide unit 3 has various optical systems such as a taper rod that appropriately adjusts the parallelism and the like.
  • the LEDs 2a, 2b, and 2c are sequentially turned on in a time-sharing manner, and the illumination light is guided to the common light guide unit 3 by the light combining element 6, and this light guide
  • the unit 3 leads to the transmissive liquid crystal display panel 4.
  • the illumination light on which the display image is superimposed by passing through the transmissive liquid crystal display panel 4 is magnified by the projection optical unit 5 and projected onto the screen S. As a result, the display image is projected on the screen S.
  • the transmissive liquid crystal display panel 4 is driven and controlled in synchronization with the lighting timing of the LEDs 2a, 2b, and 2c. Specifically, LED2c emits light based on the red video signal during the period in which LED2a emits light, and LED2c emits based on the green video signal in the period in which LED2b emits light. During the period, the transmissive liquid crystal display panel 4 is driven and controlled based on the blue video signal. Since the light emission periods of the LEDs 2a, 2b, and 2c are set to be very short, the observer can have a visual effect that is almost the same as when white illumination light is irradiated.
  • the LEDs 2a, 2b, 2c and the transmissive liquid crystal display panel 4 are controlled by the control unit 10.
  • the control unit 10 includes an image processing circuit 11, a panel drive circuit 12, a CPU 13, and a light source drive circuit 14 as main components.
  • a video signal is input to the image processing circuit 11.
  • the image processing circuit 11 performs known image processing such as interpolation processing and gradation correction processing on the input video signal, and detects the feature amount of the display image based on the video signal corresponding to one frame. .
  • the image processing circuit 11 includes a ⁇ correction circuit 15, a feature amount detection circuit 16, and a gain adjustment circuit 17 as main components.
  • the ⁇ correction circuit 15 generates a linear video signal by performing ⁇ correction on the video signal.
  • the feature amount detection circuit 16 detects the feature amount of the display image based on the video signal corresponding to one frame input from the ⁇ correction circuit 15, outputs the detected feature amount to the CPU 13, and outputs a gain adjustment circuit 17. The feature amount and the video signal are output to
  • the feature amount detection circuit 16 detects feature amounts relating to the luminance of each color from the video signal corresponding to one frame, specifically, the maximum gradation values Rmax, Gmax, Bmax, and these maximum gradation values Rmax. , Gmax, Bmax are output to the CPU 13, and the maximum gradation values R max, Gmax, Bmax and the video signal are output to the gain adjustment circuit 17.
  • the gain adjustment circuit 17 adjusts the level of each light quantity of red, green, and blue, outputs the adjusted video signal to the panel drive circuit 12, and outputs the adjustment state to the CPU 13. Specifically, when the maximum gradation values Rmax, Gmax, and Bmax of each color in the display image are input from the feature amount detection circuit 16, the gain adjustment circuit 17 inputs the maximum gradation values Rmax, Gmax, and Bmax into the image. The gradation value of each pixel of the video signal is corrected so that the maximum display gradation value (for example, 255) of the projection apparatus is obtained, and the corrected video signal is output to the panel drive circuit 12.
  • the maximum display gradation value for example, 255
  • the gain adjustment circuit 17 applies 255 / Rmax to the gradation value of each pixel of the video signal as shown in FIG.
  • the video signal related to the panel transmittance is corrected, and the corrected video signal is output to the panel drive circuit 12.
  • the gain adjustment circuit 17 outputs to the CPU 13 a value obtained by correcting the gradation value of the video signal output to the panel drive circuit 12 to be higher. Specifically, as described above, the gradation of each pixel When 255 / Rmax is multiplied by the value, this coefficient 255 / Rmax is output to CPU13.
  • the CPU 13 corrects the light quantity by multiplying the light quantity of each color by the reciprocal Rmax / 255 of this coefficient.
  • the panel drive circuit 12 changes the transmittance of the transmissive liquid crystal display panel 4 for each pixel based on the gradation value of the video signal from the image processing circuit 11. Thereby, the transmittance of each pixel of the transmissive liquid crystal panel 4 is adjusted according to the video signal. As a result, as described above, the illumination light incident on the transmissive liquid crystal display panel 4 is not converted into the video signal. The display image based on it will be superimposed.
  • the CPU 13 generates control signals for driving and controlling the respective LEDs 2a, 2b, and 2c based on the feature amount and the video signal from the image processing circuit 11, and the generated control signals are used as the light source driving circuit. Output to 14. Specifically, the CPU 13 variably controls the magnitude of the drive current of each LED 2a, 2b, 2c to adjust the amount of light emitted from each LED 2a, 2b, 2c, and each LED 2a , 2b, 2c by controlling the duty ratio of the drive current, respectively, and a second control mode for adjusting the amount of light emitted from each LED 2a, 2b, 2c.
  • the CPU 13 selects one or both of the first control mode and the second control mode according to the feature amount, and sends control signals for the LEDs 2a, 2b, 2c based on the selected control mode. These are generated and output to the light source drive circuit 14.
  • the light source drive circuit 14 applies a drive current to each LED 2a, 2b, 2c based on each control signal from the CPU 13. As a result, the light emission amounts of the LEDs 2a, 2b, 2c are controlled based on the video signal.
  • the CPU 13 is supplied with a mode instruction signal from the user I / F 18 and a power signal from the power circuit 19.
  • User I / F18 has mode specified by user If it is, a signal corresponding to the designated mode is output to the CPU 13 as a mode instruction signal.
  • the power supply circuit 19 determines whether power is supplied from an AC adapter (not shown) or power is supplied from a notch (not shown). Output to CPU13 as power supply signal.
  • the first control mode is a control mode in which the amount of light of each LED 2a, 2b, 2c is adjusted by increasing or decreasing the magnitude of the drive current of each LED 2a, 2b, 2c.
  • the maximum current Imax is set to, for example, the maximum value that can be applied to each LED 2a, 2b, 2c during normal operation. This maximum current Imax is a value that can be set individually for each LED 2a, 2b, 2c.
  • the amount of light emitted from each LED 2a, 2b, 2c is adjusted by changing the magnitude of the drive current applied to each LED 2a, 2b, 2c.
  • the second control mode is a control mode in which the light intensity of each LED 2a, 2b, 2c is adjusted by variably controlling the duty ratio of the drive current of each LED 2a, 2b, 2c.
  • the magnitude of the drive current applied to each LED 2a, 2b, 2c is not changed, for example, by making the maximum current Imax constant and adjusting the current application time, Adjust the amount of light emitted from each LED2a, 2b, 2c.
  • FIG. 7 shows general characteristics of the light amount and the power consumption with respect to the drive current of each LED 2a, 2b, 2c.
  • the horizontal axis represents relative drive current
  • the vertical axis represents relative light intensity or power consumption.
  • each LED 2a, 2b, 2c tends to saturate when the drive current increases to some extent.
  • the power consumption of each LED2a, 2b, 2c increases as the drive current increases, and the increase width ⁇ ⁇ gradually increases as the applied current increases (in Fig. 7, ⁇ ⁇ ⁇ ⁇ ⁇ 1 ⁇ ⁇ 2 ). This is because the forward effect voltage of LEDs 2a, 2b, and 2c slightly increases as the drive current increases.
  • the first control mode is compared with the second control mode by the force S, which effectively reduces the power consumption.
  • FIG. 8 is a diagram showing on the xy color diagram the color expression gamut of red, green, and blue light from the LEDs 2a, 2b, and 2c.
  • the drive current of each LED2a, 2b, 2c is small, it has a wide color gamut as shown by the broken line in the figure, but when the drive current of each LED2a, 2b, 2c is large, red, green, blue
  • Each color tone changes as indicated by the solid line in the figure, and the color expression range tends to narrow.
  • the color tone of the illumination light changes greatly with the increase or decrease of the drive current, especially in the LED 2b that emits green illumination light.
  • LED 2a that emits red illumination light and LED 2c that emits blue illumination light the color change due to increase or decrease in drive current is hardly affected by the drive current.
  • the first control mode that variably controls the magnitude of the drive current of the LEDs 2a, 2b, and 2c is highly effective in reducing the power consumption. As shown in FIG. 8, it has a characteristic that the color tone of the green illumination light changes.
  • the feature quantity detection circuit 16 uses a feature quantity related to the brightness of the display image from the video signal corresponding to one frame, for example, the maximum gradation of each color. Detects max, Gmax, Bmax, outputs these maximum gradation levels Rmax, Gmax, Bmax to the CPU 13, and outputs these maximum gradation levels Rmax, Gmax, Bmax and the video signal to the gain adjustment circuit 17. .
  • the gain adjustment circuit 17 adjusts the level of the video signal of each color based on the maximum gradation values Rmax, Gmax, and Bmax, thereby generating a video signal related to the panel transmittance and a video signal related to the light amount.
  • the video signal related to the transmittance is output to the panel drive circuit 12 and the video signal related to the light quantity is output to the CPU 13.
  • the CPU 13 determines whether the maximum gradation values Rmax, Gmax, Bmax are equal to or greater than a preset threshold value. For the LED corresponding to the color for which the maximum gradation values Rmax, Gmax, and Bmax are determined to be greater than or equal to the threshold value, control by the second control mode is selected, and the maximum gradation value is less than the threshold value. The first control mode is selected for the LED corresponding to the color judged to be present.
  • the CPU 13 As indicated by a in 9, the CPU 13 generates a control signal that applies the maximum current Irmax to the LED 2 a for a period of one frame, and outputs this to the light source drive circuit 14.
  • the CPU 13 As shown in b of 9, the CPU 13 generates a control signal having a duty ratio corresponding to the maximum gradation value Rmax for the LED 2 a and outputs the control signal to the light source driving circuit 14.
  • the current application time is set longer as the maximum gradation straight Rmax is larger. It should be noted that an optimal value can be selected for the panelless driving cycle depending on the design items.
  • the CPU 13 When the maximum red gradation value Rmax is less than the threshold, the CPU 13 has a predetermined duty ratio with respect to the LED 2a as shown in c of FIG. Then, a control signal in the form of a current corresponding to the maximum gradation value Rmax is generated and output to the light source driving circuit 14.
  • the predetermined duty ratio is determined by adopting the duty ratio when the maximum gradation value Rmax matches the threshold value.
  • the CPU 13 does not increase or decrease the current value in the pulse-like waveform, as shown in FIG. 9c, and the current corresponding to the maximum gray level straight Rmax is 1 frame as shown in FIG. A control signal that is continuously applied over a period may be generated.
  • the CPU 13 similarly generates control signals for the LEDs 2b and 2c and outputs them to the light source drive circuit 14.
  • the light source drive circuit 14 When the light source drive circuit 14 receives the control signal generated in this way, the light source drive circuit 14 applies a drive current based on each control signal to each LED 2a, 2b, 2c.
  • the LEDs 2a, 2b, and 2c of each color emit light sequentially with the light amount corresponding to the maximum gradation values Rmax, Gmax, and Bmax, and each illumination light is transmitted through the color composition unit 6 and the light guide unit 7 to the transmissive liquid crystal display. After being guided to the display panel 4 and subjected to light modulation based on the video signal, it is projected onto the screen S by the projection optical unit 5. As a result, the projected image is displayed on the screen S.
  • the feature amount related to the luminance of the display image is detected from the video signal corresponding to one frame, and the control mode is set based on the detection result. Since the selection is made, each LED 2a, 2b, 2c can be driven and controlled in an optimal control mode according to the brightness of the display image.
  • the second control mode that does not change the magnitude of the drive current is selected to reduce the color tone rather than reducing the power consumption. Emphasis on.
  • the first control mode is selected to emphasize the reduction of power consumption over the change in color tone.
  • the brightness of the display image is detected for each color, and each LED 2a, 2b, 2c is driven and controlled in a control mode corresponding to the brightness, so that all the LEDs 2a, 2b , 2c can be driven more precisely than in the case of driving control in the same control mode.
  • the threshold value used by the CPU 13 is set individually for each color. For example, as shown in FIG. 8, for red and blue, the change in color tone due to increase / decrease in the drive current is small, so the power consumption can be effectively reduced by setting the threshold value higher. 1 Actively adopt control mode For green, the change in color tone due to increase / decrease in drive current is larger than that for other colors, so setting the above threshold value lower than for other colors results in a change in color tone and a reduction in power consumption. Adjust the balance. As a result, power S can be reduced more effectively to reduce power consumption.
  • the force is such that the maximum gradation value is detected from the video signal corresponding to one frame and the control mode can be switched in one frame period.
  • control mode can be switched at a period of a plurality of frames by detecting the maximum gradation value of the video signal power corresponding to the plurality of frames.
  • the maximum gradation value of each color of the display image formed based on the video signal is detected, and the control is adopted depending on whether or not the maximum gradation value is equal to or greater than the threshold value.
  • Force S which determined the mode, instead of this, the average gradation value in the display image is obtained for each color, and the second control mode (see Fig. 6) is adopted when this average gradation value is equal to or greater than the threshold value.
  • the first control mode see Fig. 5
  • the control mode that combines the second control mode and the first control mode see Fig. 9c
  • the display image is detected by detecting pixels for which the gradation value is greater than or equal to the threshold for each color.
  • the second control mode (see Fig. 6) is adopted when the number of pixels is greater than or equal to the preset reference number of pixels, and the first control mode is selected when the number of pixels is less than the reference number of pixels.
  • a control mode (see c in Fig. 9) that is a combination of the second control mode and the first control mode.
  • the method for determining whether the display image is bright or not is not limited to the method described above.
  • the second control mode that does not change the color tone is set when the criteria for judging whether or not the display image is bright is set appropriately and the display image is judged to be bright based on this criteria. If it is determined that the displayed image is long, the first control mode is accompanied by a change in color tone but has a high power consumption reduction effect, or a control mode that combines the second control mode and the first control mode. Should be adopted.
  • the maximum luminance value is detected for each color, and based on this maximum luminance value. Therefore, the power to select the control mode of each LED2a, 2b, 2c. Instead, all LEDs 2a, 2b, 2c are the same according to the overall brightness of the display image including red, green, and blue. It ’s a good idea to do this in the wholesale mode!
  • the ability to determine whether the display image is bright or not can be determined arbitrarily. For example, pixels with a gradation value greater than or equal to a predetermined value are extracted from the video signal in one frame, and the number of pixels is If the number of pixels is equal to or greater than the preset reference pixel number, the display image is judged to be bright and all LEDs 2a, 2b, 2c are driven and controlled in the second control mode. If it is less than the number, it may be determined that the display image is long and all the LEDs 2a, 2b, 2c may be driven and controlled in the first control mode. Further, an average gradation value in one frame may be obtained, and it may be determined whether or not the display image is bright based on whether or not the average gradation value is equal to or greater than a threshold value.
  • the control mode designated by the user may be preferentially adopted.
  • the CPU 13 when the CPU 13 receives a signal for designating the first control mode from the user I / F 18, it drives and controls the LEDs 2a, 2b, 2c in the first control mode.
  • the user's intention can be reflected in the drive control of the LEDs 2a, 2b, 2c.
  • the user may select a control mode for each color.
  • a judgment criterion for judging whether the display screen is bright or not such as the threshold value and the number of reference pixels, can be configured by the user! /, .
  • the CPU 13 may switch the control mode based on the power signal from the power circuit 19. For example, since power is supplied from the AC adapter and the power signal indicating the state of V is input, the power that can be consumed is not limited. Employing modes emphasizes color tone over power consumption. On the other hand, during the period when the power supply signal indicating that the power is being supplied from the battery is input, the usable power is limited. Therefore, the CPU 13 operates in the first control mode or the first control described above. Consists of a combination of control mode and second control mode By adopting the control mode, the effect of reducing power consumption is enhanced while allowing color change. Thus, the control mode may be switched according to the power supply state. In addition, when power is supplied from the battery, the control mode can be switched according to the remaining capacity of the battery! /.
  • the first control mode is adopted for colors having a small color change due to increase / decrease in drive current, i.e., red and blue, and colors having a large color change due to increase / decrease in drive current, That is, the second control mode is adopted for green.
  • the control mode is properly used for each color, so that the processing load on the image processing circuit 11 and the CPU 13 can be greatly reduced.
  • the image projection apparatus according to the present embodiment is based on the first embodiment described above in that the control mode is selected according to the color component bias of the display image formed based on the video signal! Different from the image projector.
  • FIG. 10 and FIG. 11 are diagrams in which the color tone of each pixel of the display image formed based on the video signal is plotted in the xy space with reference to the three primary colors of sRGB. An example of an image is shown in Fig. 11.
  • the control unit 10 of the image projection apparatus detects the color tone deviation of the display image from the video signal corresponding to one frame in the feature amount extraction circuit 16, and the CPU 13 based on the detection result. Determines the control mode to be adopted.
  • the color tone of each pixel can be easily determined by performing a matrix calculation process using a known technique, for example, using the RGB signal level of each pixel in the video signal and the matrix of each tristimulus value XYZ of the RGB primary colors. It can be sought.
  • the CPU 13 adopts the second control mode to suppress the color change due to the change in the magnitude of the drive current. Further, the CPU 13 adopts the second control mode for a large number of colors (for example, red in the display image shown in FIG. 11) when the color tone is uneven, thereby increasing the drive current. The color change due to the change in height is suppressed, while for the rarely included colors (for example, green and blue in Fig. 11), the first control mode is used to effectively reduce power consumption.
  • the control mode is selected based on the color deviation of the display image formed based on the video signal. It is possible to effectively reduce power consumption while keeping the color tone change within an allowable range.
  • the first control mode is always adopted for red and blue that are not affected by the color due to the magnitude of the current, regardless of the color tone, and the color changes according to the change in the magnitude of the current. Only for green, which is easy to do, the control mode may be selected according to the color tone deviation. As described above, the power consumption of the LEDs 2a and 2c can be further reduced by always adopting the first control mode.
  • each LED 2a, 2b, 2c is set to the first.
  • Control may be performed in the control mode.
  • the control mode For example, as in a presentation image, there are many pixels represented by the same color! /, And in the case of an image, the color tone of each pixel of the display image formed based on the video signal! / Is the three primary colors of sRGB
  • the number of points representing the color tone is higher than the natural image shown in Fig. 10 and Fig. 11, where the plot tends to appear linearly as shown in Fig. 12. Less is. If this is the case, don't mind the color change.
  • the first control mode that can effectively reduce power consumption should be adopted.
  • the light source unit 2 has three LEDs 2a, 2b, and 2c that emit illumination lights of different colors.
  • LED groups 2, 2b ′, 2 in which a plurality of LEDs emitting illumination light are arranged in an array on the same plane may be used.
  • the light amount control method for each LED is the same as described above.
  • a light source unit 2 ′ as shown in FIGS. 14 to 16 may be used.
  • Fig. 14 is a plan view of the light source unit 2 'when viewed from the emission end side of the illumination light
  • Fig. 15 is a longitudinal sectional view of the light source unit 2'
  • Fig. 16 is a diagram of the rotary head 20 included in the light source unit 2 '. It is a figure for demonstrating a rotation state and the transmission efficiency of light.
  • a plurality of LEDs 2a, a plurality of LEDs 2b, and a plurality of LEDs 2c are arranged on the same circumference.
  • a rotating rod 20 that can rotate around the center axis of the array.
  • the rotating rod 20 At the free end of the rotating rod 20, there is an incident end 20a for taking in the illumination light emitted from each LED, and the lighting timing of each LED 2a, 2b, 2c arranged on the same circumference is provided. Synchronously, when the rotating rod 20 is rotated around the center axis of the array, the illumination light emitted from the LEDs 2a, 2b, 2c facing the incident end 20a of the rotating rod 20 is incident on the rotating end 20a. It is taken into 20 and led to the incident end of the fixed rod 23 through the rotating rod 20.
  • each LED 2a, 2b, 2c has a desired color (for example, white) so that the combined light of the illumination light when all the LEDs 2a, 2b, 2c are turned on is turned on.
  • Determine the maximum drive current For example, as shown in FIG. 17, the maximum drive current Irmax of LED2a, the maximum drive current Igmax of LED2b, and the maximum drive current Ibmax of LED2c are set as follows.
  • the second control mode is adopted, and for red and blue, where the change in color tone due to increase / decrease in drive current is small, the first control mode is adopted to improve power consumption reduction.
  • the green power of the display image and the luminance power to be applied are preset threshold values (for example, the luminance corresponding to the amount of light obtained by the entire LED 2b when one LED 2b is completely turned off).
  • threshold values for example, the luminance corresponding to the amount of light obtained by the entire LED 2b when one LED 2b is completely turned off.
  • one LED 2b may be completely turned off, and the other LED 2b may be controlled with a duty ratio corresponding to the luminance.
  • the light transmission efficiency shows a periodic change depending on the rotation angle ⁇ . Is preferably reduced.
  • each LED 2a, 2b, 2c is led to the common transmissive liquid crystal display panel 4 through the common light guide unit 3.
  • the light guide units 3a, 3b, 3c and the transmission type night-night display non-linears 4a, 4b, 4c may be provided for the LEDs 2a, 2b, 2c, respectively.
  • each illumination light transmitted through the transmissive liquid crystal display panels 4a, 4b, 4c is guided to the same optical combining element 8, and is combined here and then guided to the projection optical unit 5. .
  • a reflective liquid crystal display panel or DMD Digital Micro Mirror
  • DMD Digital Micro Mirror

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Projection Apparatus (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Mechanical Light Control Or Optical Switches (AREA)
  • Liquid Crystal (AREA)

Abstract

La présente invention concerne un appareil de projection d'image qui possède un premier mode de commande pour commander de manière variable le niveau d'un courant d'attaque de LED, et un second mode de commande pour commander de manière variable le rapport cyclique du courant d'attaque de LED. Une quantité de caractéristiques d'une image d'affichage est détectée à partir d'un signal vidéo qui correspond à une ou une pluralité de trames, et en fonction de la quantité de caractéristiques, soit le premier mode de commande ou le second mode de commande ou les deux sont sélectionnés, et dans le mode de commande sélectionné, une commande d'attaque de LED est effectuée.
PCT/JP2007/070329 2006-10-20 2007-10-18 Appareil de projection d'image WO2008047856A1 (fr)

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JP2006286675A JP2008102442A (ja) 2006-10-20 2006-10-20 画像投影装置
JP2006-286675 2006-10-20

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JP2010181695A (ja) * 2009-02-06 2010-08-19 Ntt Docomo Inc 画像表示制御装置、及び、画像表示制御方法
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JP4686644B2 (ja) * 2009-07-07 2011-05-25 シャープ株式会社 液晶表示装置
JP4648481B1 (ja) * 2009-12-07 2011-03-09 ▲高▼橋 厚子 簡易浴槽
JP5388894B2 (ja) * 2010-02-19 2014-01-15 三菱電機株式会社 表示装置
CN102472895B (zh) 2010-04-20 2014-08-13 松下电器产业株式会社 图像显示装置
JP5673024B2 (ja) * 2010-11-26 2015-02-18 セイコーエプソン株式会社 画像表示装置、画像表示システム及び画像表示方法
WO2014112032A1 (fr) * 2013-01-15 2014-07-24 Ｎｅｃディスプレイソリューションズ株式会社 Dispositif d'affichage d'image et procédé d'affichage d'image
JP6880584B2 (ja) * 2016-07-12 2021-06-02 株式会社リコー 調光装置及び調光方法
JP7162243B2 (ja) * 2018-10-16 2022-10-28 パナソニックＩｐマネジメント株式会社 半導体光源駆動装置及び投射型映像表示装置
CN110095256B (zh) * 2019-05-08 2021-12-07 歌尔股份有限公司 投影仪光机测试***及方法

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