JP2011118067A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make color breakup and flicker less perceivable without increasing time-sharing color number in a frame and also without increasing a data transfer quantity. <P>SOLUTION: A drive pattern which drives a liquid crystal element of LCOS104 is divided into three drive patterns. Each region in a display screen of a screen 109 driven by each of the three drive patterns is predetermined and is driven according to each drive pattern. The first drive pattern outputs video data R(n), G(n) and B(n) sequentially in synchronization with time-sharing lighting of a light source in one-frame period. The second drive pattern outputs G(n), B(n) and R(n) sequentially in one-frame period which is delayed 1/3-frame period. The third drive pattern outputs B(n), R(n) and G(n) sequentially in synchronization with time-sharing lighting of light sources of 101G, 101B and 101R in one-frame period which is delayed 2/3-frame period to drive the liquid crystal element. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image display device, and more particularly to a field sequential color image display device that synthesizes colors by lighting a plurality of light sources in a time-sharing manner.

  A conventional field sequential color image display device emits red light, green light, and blue light from a light source in order and cyclically, and the light is, for example, a reflective liquid crystal panel (LCOS). (Silicon). The LCOS is a liquid crystal panel in which each of a plurality of pixels is composed of a reflective pixel electrode. LCOS has a structure in which a liquid crystal layer is sandwiched between a transparent electrode and a reflective electrode. By applying a voltage between the transparent electrode and the reflective electrode, the alignment state of the liquid crystal in the liquid crystal layer is changed. At the same time, the light applied to the LCOS is reflected by the reflective electrode through the liquid crystal layer, and further modulated and reflected according to the voltage between the transparent electrode and the reflective electrode by passing through the liquid crystal layer. The modulated light beam output from the LCOS is magnified by the projection lens and projected onto the screen.

  FIG. 11 shows an example of a field sequential color driving method in a conventional image display apparatus. One frame period of the video signal to be displayed is divided into three, and for each divided period, red, green, and blue colors are schematically shown at high levels in FIGS. 11 (A), (B), and (C). The three light sources are sequentially switched on. In synchronization with the switching lighting of these three light sources, as schematically shown in FIG. 11D, among the red signal R, the green signal G, and the blue signal B of the video signal, The signals of the same primary color are switched and input to the LCOS so that each LCOS is driven.

  As a result, the image projected on the screen is recognized by a human being in a state where the red signal, the green signal, and the blue signal of the image signal are mixed due to the afterimage effect of the eyes, so that a color image can be displayed. Such a field sequential image display device can display a high-definition image with a low-cost and small configuration.

  The above example is an example of a projection-type image display device. However, in the field sequential color method, a direct-view type that is configured to irradiate liquid crystal elements that constitute pixels in a time-division manner with three primary color lights from a backlight. There is also an image display device. This direct view type image display device does not require a color filter and can realize high-definition video display at low cost.

  However, both the projection type and the direct-view type image display devices of the field sequential color method have the feature that a high-definition image can be realized at low cost, but when moving a movie or a viewpoint, color breakup or the like. A phenomenon called color break or the like occurs, and there is a drawback that the color divided into red (R), green (G), and blue (B) is easily perceived by the outline of the display object. As shown in FIG. 12, for example, a phenomenon called color break or color break occurs when LCOS is irradiated with red light, green light, and blue light in a time-sharing manner in a scene where a white straight line 11 moves on a display screen. However, since the primary color straight lines before moving the viewpoint are stationary, the red, green, and blue straight lines overlap and appear as a single white straight line 11, but the straight line 11 moves. This is a phenomenon in which straight lines of primary colors do not overlap on the human retina and appear to be divided into a red line 12R, a green line 12G, and a blue line 12B.

  In order to solve this drawback, an image display device that changes the lighting order of the three light sources R, G, and B for each frame has been proposed (for example, see Patent Document 1). According to this conventional image display apparatus, the color appearing at the top in the space is sequentially switched, so that it is difficult for an observer to perceive color breakup.

JP 2002-223453 A

  However, the conventional image display device described in Patent Document 1 has a drawback in that flicker occurs particularly when displaying a monochrome image because the image display period of the same primary color in the frame changes from frame to frame.

  In addition to the above methods, various methods for reducing or eliminating the phenomenon called color breakup or color break have been proposed, but all have drawbacks. For example, the method of reducing color breakup by increasing the number of R, G, and B colors in one frame has a disadvantage that the cost increases because the amount of data increases, and in particular, a liquid crystal is used. In the case of an image display device, color mixing is likely to occur due to the slow response speed of the liquid crystal. In order to avoid color mixing, it is necessary to set a longer non-driving period between the lighting of the light sources. In this case, there is a disadvantage that the modulation rate is lowered and luminance is not easily produced.

  In addition to R, G, and B, methods of inserting complementary colors of R, G, and B, such as yellow (Y), cyan (C), and magenta (M), and white have also been proposed. The problem is great.

  The present invention has been made in view of the above points, and does not increase the number of time-division colors in a frame, and does not increase the amount of data transfer. The purpose is to provide.

  In order to solve the above object, the image display device according to the first aspect of the present invention lights up N (N is a natural number of 3 or more) light sources emitting colored light of a predetermined wavelength in a time-sharing and cyclic manner. The light source means for controlling, the three buffers each having a storage capacity for one frame of the video signal to be displayed, and the three buffers, one driving buffer for performing the reading operation in the same one frame period, and the first for performing the writing operation. And the second holding buffer is assigned and operated, and the buffer assigned to the driving buffer is switched in order of the second holding buffer, the first holding buffer, and the driving buffer every frame period, and cyclically. The buffer assigned to the first holding buffer is assigned one buffer in the order of the driving buffer, the second holding buffer, and the first holding buffer. Switching for each frame period and cyclically allocating, and the buffer allocated to the second holding buffer is switched for each frame period in the order of the first holding buffer, the driving buffer, and the second holding buffer, and A buffer control means for cyclically assigning, a setting means for switching and setting N driving patterns from the first to the N-th in a predetermined order in units of lines or pixels of a display image of a video signal to be displayed, and N pieces When the video data of the same color as the N color lights output in a time-sharing manner from the light source is C1, C2,..., CN, the video data C1 to C1 in the lines or pixels of the first drive pattern CN is held in the first holding buffer, and the video data Cm to CN are stored in the first holding buffer in the lines or pixels of the mth driving pattern (m is a natural number of 2 to N). And the video data holding control means for holding the video data C1 to Cm-1 in the second holding buffer, N color lights from the N light sources are irradiated in a time division manner, and N In synchronization with the switching lighting of the light source, the driving is set in the same color as the color light emitted from the driving buffer assigned by the buffer control means, and set by the setting means according to the line or pixel of the display image to be driven And a display element that outputs modulated color light supplied with image data of a pattern.

  In order to achieve the above object, according to the second invention, N in the first invention is set to 3, and the three light sources are controlled to be turned on in a time-sharing manner every 1/3 frame period so that red light, green The light and the blue light are output in a time-sharing and cyclic manner, respectively, and the setting means outputs the first, second and third drive patterns in units of lines or pixels of the display image of the video signal to be displayed. The video data retention control means outputs primary color light cyclically in the order of the first primary color light, the second primary color light, and the third primary color light from the three light sources. In the video signal to be displayed, the video data of the same color as the first primary color light is C1, the video data of the same color as the second primary color light is C2, and the video data of the same color as the third primary color light is displayed. Assuming C3, the video data C1, C2 and the video data C1 and C2 in the first drive pattern line or pixel. C3 is held in the first holding buffer, the video data C2 and C3 are held in the first holding buffer and the video data C1 is held in the second holding buffer in the second drive pattern line or pixel. In the third drive pattern line or pixel, the video data C3 is held in the first holding buffer, and the video data C1 and C2 are held in the second holding buffer.

  According to the present invention, the number of time-division colors in a frame is increased by changing the order of the colors of the display video for each line or pixel without changing the lighting order of the light source, and displaying the display image in synchronization with the lighting of the light source. This makes it difficult for an observer to perceive color breakup and flicker without increasing the data transfer amount.

1 is a basic configuration diagram of an embodiment of an image display device of the present invention. It is a block diagram of an example of the driver in FIG. 2 is a timing chart for explaining the operation of the image display apparatus in FIG. 1. FIG. 7 is an explanatory diagram of buffering operations of three buffers of the image display device of FIG. 1. FIG. 6 is an explanatory diagram of switching operation of three buffers in the image display device of FIG. 1. It is a figure which shows the linear drive pattern in the image display apparatus of this invention. It is a figure explaining the effect of one Embodiment of the image display apparatus of this invention. It is a figure which shows the grid | lattice-like drive pattern in the image display apparatus of this invention. It is buffering operation explanatory drawing with respect to three buffers of the video data of three colors in the image display apparatus of this invention. It is buffering operation explanatory drawing with respect to three buffers of the video data of four colors in the image display apparatus of this invention. It is a timing chart for explaining operation of an example of a conventional image display device. It is problem explanatory drawing of the conventional image display apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a basic configuration diagram of an embodiment of an image display apparatus according to the present invention. As shown in the figure, an image display device 100 according to the present embodiment includes light sources 101R, 101G, and 101B that emit primary color lights having predetermined wavelengths different from each other, which are configured by light emitting diodes (LEDs). An X prism 102, a polarizing element 103 such as a wire grid (Wire_Grid), a reflective liquid crystal panel (LCOS) 104, a driver 105 as a driving circuit, and a storage capacity 3 for holding video data for one frame. Two buffers 106a, 106b and 106c and a projection lens 108 are included.

  The light source 101R emits red light, the light source 101G emits green light, and the light source 101B emits blue light. The light sources 101R, 101G, and 101B are driven by a control circuit (not shown) sequentially and cyclically switched for each field (1/3 frame period) obtained by dividing one frame into three, respectively, red light, Emits green and blue light. These light sources 101R, 101G, and 101B and a control circuit (not shown) constitute light source means.

  The X prism 102 emits light from the other one side by combining the optical axes of the red light, the green light, and the blue light separately incident from the three side surfaces. A polarizing element 103 such as a wire grid transmits the P-polarized component of incident light and reflects the S-polarized component.

  The LCOS 104 is a liquid crystal panel in which a large number of reflective pixels are arranged in a two-dimensional matrix, for example. The pixel has a structure in which a liquid crystal layer is sandwiched between a transparent electrode and a reflective electrode.

  FIG. 2 shows a block diagram of an example of the driver 105. The driver 105 determines the pattern indicating the color order from the pixel position information of the video data to be displayed, and the video data whose color order is determined by the color order pattern determination unit 151 as red (R). , Green (G) and blue (B) RGB separation unit 152 that decomposes into primary color video data, and color data of these primary color video data in holding 1 buffer 106-1 and holding 2 buffer 106-2, which will be described later. In accordance with the driving pattern indicating the order, the video data sorting unit 153 supplied for each color and the video data reading unit 154 that reads out and outputs the video data read from the driving buffer 106-3 described later.

  The holding 1 buffer 106-1, the holding 2 buffer 106-2, and the driving buffer 106-3 are assigned with the buffers 106a, 106b, and 106c constituting the triple buffer shown in FIG. That is, any one of the buffers 106a, 106b, and 106c is assigned to the drive buffer 106-3, and the remaining two buffers are assigned to the holding 1 buffers 106-1 and 106-2, respectively. Further, the assignment is switched for each frame period by a buffer control means (not shown) as described later with reference to FIG.

  The three buffers 106a, 106b, and 106c shown in FIG. 1 are drive buffers (FIG. 1) that supply video data temporarily held by one of the buffers to the transparent electrode of the LCOS 104 in the same frame period. 106-3), and the remaining two buffers operate as a holding 1 buffer (106-1 in FIG. 2) and a holding 2 buffer (106-2 in FIG. 2) for temporarily writing and storing the input video data. A triple buffer is configured.

  Of the three buffers 106a, 106b and 106c, the buffer serving as the driving buffer and the buffer serving as the holding 1 buffer and the holding 2 buffer are switched every frame as will be described later. The projection lens 108 projects the S-polarized component of the reflected light from the LCOS 104 reflected by the polarizing element 103 onto the screen 109 and displays a color image 110.

  Next, the operation of the image display apparatus 100 of the present embodiment will be described with reference to the timing chart of FIG. 3, the buffer operation explanatory diagrams of FIGS. 4 and 5, the drive pattern diagram of FIG. In FIG. 1, the light sources 101R, 101G, and 101B are driven and controlled so that they are sequentially turned on every 1/3 frame period obtained by dividing one frame period of video data to be displayed into three, and are turned on cyclically. Is done. 3A schematically illustrates the lighting period of the light source 101R, the high level period of FIG. 3B schematically illustrates the lighting period of the light source 101G, and the high level period of FIG. 3C schematically illustrates the lighting period of the light source 101B. Indicate.

  The red light emitted from the light source 101R, the green light emitted from the light source 101G, and the blue light emitted from the light source 101B enter the X prism 102, where the optical axes are aligned, and then the polarizing element Only the P-polarized component is transmitted through 103 and irradiates LCOS 104.

  The liquid crystal of the liquid crystal element constituting the pixel of the LCOS 104 has an orientation state according to a voltage applied between the transparent electrode and the reflective electrode (that is, video data from the buffer 106a, 106b or 106c operating as a drive buffer). Therefore, the video data from the buffer 106a, 106b or 106c that operates as a driving buffer when the P-polarized component of the primary color light transmitted through the polarizing element 103 passes through the liquid crystal through the transparent electrode of the liquid crystal element constituting the LCOS 104 pixel. In response to the light, the light is incident on the reflective electrode, and the light reflected by the reflective electrode is modulated again when passing through the liquid crystal and is transmitted through the transparent electrode.

  Thereby, the LCOS 104 emits the reflected light modulated by the video data from the buffer 106a, 106b or 106c operating as a drive buffer. The modulated reflected light from the LCOS 104 is incident on the polarizing element 103 again, where only the S-polarized component is reflected, magnified by the projection lens 108 and projected onto the screen 109. As a result, the screen 109 displays an image 110 corresponding to the image data from the buffer 106a, 106b or 106c that operates as a drive buffer.

  Here, as in the conventional field sequential color system, in the 1/3 frame period in which red light is incident on the LCOS 104, red video data is input to the transparent electrode of the liquid crystal element, and green light is incident on the LCOS 104. In the 1/3 frame period, green image data is input to the transparent electrode of the liquid crystal element, and in the next 1/3 frame period in which blue light is incident on the LCOS 104, the blue image data is input to the transparent electrode of the liquid crystal element. Is entered.

  However, in the present embodiment, the drive pattern for driving the liquid crystal element is divided into three drive patterns, and the area on the display screen of the screen 109 driven by each of the three drive patterns is set in advance, and each drive pattern is The driving point is different from the conventional one. Hereinafter, for convenience of explanation, the first drive pattern among the above three drive patterns will be described as “drive A”, the second drive pattern as “drive B”, and the third drive pattern as “drive C”.

  As schematically shown in FIG. 3D, “Drive A” is synchronized with time-division lighting for each 1/3 frame period of the light sources 101R, 101G, and 101B within one frame period as in the prior art. , Red video data R (n), green video data G (n), and blue video data B (n) are sequentially output to drive the liquid crystal element.

  On the other hand, “drive B” and “drive C” have different drive patterns. That is, as schematically shown in FIG. 3E, “drive B” is 1/3 of the light sources 101G, 101B, and 101R within one frame period delayed from “drive A” by 1/3 frame period. A pattern for driving the liquid crystal element by sequentially outputting green video data G (n), blue video data B (n), and red video data R (n) in synchronization with time-division lighting for each frame period. It is.

  Further, as schematically illustrated in FIG. 3F, “drive C” is 1/3 of the light sources 101B, 101R, and 101B within one frame period that is delayed by 2/3 frame period from “drive A”. A pattern for driving the liquid crystal element by sequentially outputting blue video data B (n), red video data R (n), and green video data G (n) in synchronization with time-division lighting for each frame period. It is. 3D to 3F illustrate output video data from one buffer operating as a drive buffer among the three buffers 106a to 106c for each drive pattern.

  Here, for example, as shown in FIG. 6, the display screen of the screen 109 is driven by a line 201A driven by “drive A”, a line 201B driven by “drive B”, and “drive C” for each line. The line 201 </ b> C is periodically set in advance by setting means (not shown).

  As a result, of the three buffers 106a to 106c, one buffer operating as the drive buffer is determined by “drive A” shown in FIG. 3D for each pixel (liquid crystal element) on the line 201A. The video data R (n), G (n), and B (n) are output in the pattern thus obtained. Similarly, one buffer operating as the above-described drive buffer has each pixel (liquid crystal element) of the line 201B having a pattern defined by “drive B” shown in FIG. (N), B (n), and R (n) are output, and each pixel (liquid crystal element) on the line 201C has a pattern defined by “drive C” shown in FIG. Each video data B (n), R (n), G (n) is output.

  Here, of the three buffers 106a, 106b, and 106c, one buffer is assigned to the drive buffer (106-3 in FIG. 2) and operates by the buffer control means (not shown), and the remaining two buffers are held 1 The operation is performed by being assigned to the buffer (106-1 in FIG. 2) and the holding 2 buffer (106-2 in FIG. 2), and these assignments are switched every frame.

  For example, assuming that the driving buffer is the buffer 106c, the buffer 106b is the holding 1 buffer, and the buffer 106a is the holding 2 buffer, and operates in one frame period, the following one frame period is schematically illustrated in FIG. As shown, the buffer 106a is switched to the holding 1 buffer, the buffer 106b is switched to the driving buffer, and the buffer 106c is switched to the holding 2 buffer.

  In the next one frame period, as schematically shown in FIG. 5, the buffer 106a is switched to the driving buffer, the buffer 106b is switched to the holding 2 buffer, and the buffer 106c is switched to the holding 1 buffer. Further, in the next one frame period, the first allocation is returned, and the buffer 106a becomes the holding 2 buffer, the buffer 106b becomes the holding 1 buffer, and the buffer 106c becomes the driving buffer. In the same manner as described above, the allocation of the driving buffer, the holding 1 buffer, and the holding 2 buffer of the three buffers 106a to 106c is cyclically switched every frame period. Thus, data can be held and driven smoothly, and video data of each primary color is always output from the drive buffer according to the three drive patterns as shown in FIGS. In FIG. 5, (W) indicates a buffer that performs a write operation, and (R) indicates a buffer that performs a read operation.

  In order for one buffer to operate as a driving buffer that outputs video data in the above three driving patterns, the one buffer operates as a holding 1 buffer or a holding 2 buffer before being assigned as a driving buffer. Sometimes it is necessary to write video data for each primary color in a predetermined color order pattern.

  Next, the video data writing operation of two buffers (holding 1 buffer and holding 2 buffer) that operate as holding buffers among the three buffers 106a to 106c will be described. This video data writing operation is performed by the video data holding control means including the color order pattern determination unit 151, the RGB color separation unit 152, and the video data distribution unit 153 shown in FIG.

In FIG. 2, the color order pattern determination unit 151 determines, for example, the following expression p = mod (x + y, 3) from the pixel position information (x, y) of the video data
Is used to calculate the color order pattern identification number p. Here, the above-described mod (a, b) indicates a remainder of a / b. Here, drive A is assumed when p = 0, drive B when p = 1, and drive C when p = 2.

  As shown in FIG. 4A, the video data distribution unit 153 schematically illustrates pixels that drive “drive A” in accordance with the identification number p for each pixel calculated by the color order pattern determination unit 151. In addition, in the holding 1 buffer (106-1 in FIG. 2), the next red video data R (n + 1), green video data G (n + 1), and blue video data B (n + 1) that are currently being driven are stored. At this time, nothing is written in the holding 2 buffer (160-2 in FIG. 2).

  Next, for the pixels that drive “drive B”, the video data distribution unit 153 stores the next order that is currently being driven in the holding 1 buffer, as schematically shown in FIG. The green video data G (n + 1) and the blue video data B (n + 1) are written, and at the same time, the red video data R (n + 1) is written in the holding 2 buffer.

  Next, for the pixels that drive “drive C”, the video data distribution unit 153 stores the next order that is currently being driven in the holding 1 buffer, as schematically shown in FIG. In parallel with this, red video data R (n + 1) and green video data G (n + 1) are written in the holding 2 buffer.

  The holding 1 buffer (106-1 in FIG. 2) or holding 2 buffer (106-2 in FIG. 2) in which the video data is written in this way is in the order of the driving buffer (106-3 in FIG. 2). In one frame period, the stored video data of each primary color is read by the video data reading unit 154 and output to the pixel electrode of the pixel of the LCOS 104 in FIG. At this time, the video data of each primary color read from the drive buffer is video data in the order corresponding to the drive pattern previously assigned to the display image.

  Next, the effect of this embodiment will be described with reference to FIG. As shown in FIG. 7, for example, when displaying a long straight line (vertical line) in the white vertical direction on the display screen, when the straight line is stationary, the red light, the green light, and the blue light are time-divided into the LCOS 104. Even if it is irradiated and driven by three driving patterns, the red, green, and blue straight lines overlap and appear as one white straight line 21.

  On the other hand, when the white straight line 21 moves, the straight lines of the primary colors do not overlap on the human retina, and three vertical lines 22a, 22b, and 22c are visible. However, the video data of the three pixels adjacent in the vertical direction of these three vertical lines 22a to 22c are generated by three different drive patterns of "drive A" to "drive C" as described with reference to FIG. Because they are different primary color video data that are driven, and the video data of pixels adjacent in the horizontal direction are also different primary color video data that are input in a time-sharing manner (that is, they are displayed in the same primary color lighting period). Since the position of the pixels to be different is different from top to bottom, left and right), they are mixed with the human retina so that they appear whitish to humans, so the above-described phenomenon of color breakup can be greatly reduced.

  Further, according to the present embodiment, since the lighting order of the three light sources 101R, 101G, and 101B is the same in each frame, the flicker generated in the conventional image display device that changes the lighting order of the three light sources for each frame. Does not occur. Furthermore, according to the present embodiment, the order of R, G, and B of the display image is changed for each pixel and displayed in synchronization with the lighting of the light source without increasing the number of time-division colors in the frame. In addition, color breakup and flicker can be reduced or eliminated without increasing the data transfer amount.

  Note that the present invention is not limited to the above-described embodiment. For example, pixels driven by three drive patterns are arranged in units of pixels in a grid pattern on the display screen of the screen 109 as shown in FIG. The pixel 202A driven by “drive A”, the pixel 202B driven by “drive B”, and the pixel 202C driven by “drive C” may be set in advance.

  In the embodiment shown in FIG. 1, the lighting order of the light sources is described as the order of the light source 101R, the light source 101G, and the light source 101B (that is, the order of RGB). But you can. Regardless of the order in which the three primary color lights are lit, the present invention shows that in the drive A, the video data of each primary color light corresponding to the lighting order of the three primary color lights is C1, C2, C3. As schematically shown in 9 (A), C1, C2, and C3 are held in the holding 1 buffer. Further, in the drive B, as schematically shown in FIG. 9B, C2 and C3 are held in the holding 1 buffer, and C1 is held in the holding 2 buffer. Further, in the drive C, as schematically shown in FIG. 9C, C3 is held in the holding 1 buffer, and C1 and C2 are held in the holding 2 buffer. By distributing the video data in such a procedure, the same effect as that of the embodiment shown in FIG. 1 can be obtained.

  Further, the number of colored lights is not limited to the above three, and may be four or more colors. For example, in the case of four colors, there are four types of drive patterns (drive A / drive B / drive C / drive D) indicating the color order, and the formula used in the color order pattern determination unit is mod (x + y, 4). Become. When the four video data of each color are C1, C2, C3, and C4 and are lit in that color order, the drive A holds C1, C2, C3, and C4 as schematically shown in FIG. Hold in buffer. Further, in the drive B, as schematically shown in FIG. 10B, C2, C3 and C4 are held in the holding 1 buffer, and C1 is held in the holding 2 buffer. Further, in the drive C, as schematically shown in FIG. 10C, C3 and C4 are held in the holding 1 buffer, and C1 and C2 are held in the holding 2 buffer. Further, in the drive D, as schematically shown in FIG. 10D, the video data is distributed in such a procedure that C4 is held in the holding 1 buffer and C1, C2, and C3 are held in the holding 2 buffer. Thereby, the same effect as the embodiment shown in FIG. 1 can be obtained.

  The above is the same even when the number of colors is 5 or more. In short, the video data holding control means in the present invention outputs video data of the same color as the N color lights output in a time-sharing manner from N (N is a natural number of 3 or more) light sources, C1, C2, ..., CN, the video data C1 to CN is held in the first holding buffer in the first drive pattern line or pixel, and the mth (m is a natural number from 2 to N). In the driving pattern line or pixel, the video data Cm to CN are held in the first holding buffer, and the video data C1 to Cm-1 are held in the second holding buffer.

  In the above embodiment, the field sequential color image display apparatus using the LCOS 104 has been described. However, the present invention is a field sequential color image display apparatus using a transmissive liquid crystal display element having a backlight. It is also applicable to.

100 Field Sequential Color Image Display Devices 101R, 101G, 101B Light Source 102 X Prism 103 Polarizing Element 104 LCOS (Reflective Liquid Crystal Panel)
105 Drivers 106a, 106b, 106c Buffer 106-1 Holding 1 Buffer 106-2 Holding 2 Buffer 106-3 Drive Buffer 108 Projection Lens 109 Screen 110 Video 151 Color Order Pattern Determination Unit 152 RGB Decomposition Unit 153 Video Data Sorting Unit 154 Video Data Read unit 201A Drive A line 201B Drive B line 201C Drive C line 202A Drive A pixel 202B Drive B pixel 202C Drive C pixel

Claims (2)

Light source means for controlling lighting of N (N is a natural number of 3 or more) light sources each emitting colored light of a predetermined wavelength in a time-sharing and cyclic manner;
Three buffers (106a, 106b, 106c) each having a storage capacity for one frame of a video signal to be displayed;
The three buffers are assigned and operated as one drive buffer (106-3) for performing a read operation and first and second holding buffers (106-1 and 106-2) for performing a write operation in the same one frame period. In addition, the buffer allocated to the driving buffer is switched every frame period in the order of the second holding buffer, the first holding buffer, and the driving buffer, and is cyclically allocated to the first holding buffer. The buffer assigned to the buffer is assigned to the second holding buffer by switching the driving buffer, the second holding buffer, and the first holding buffer in the order of one frame period and cyclically assigning them. Switch every frame period in the order of the first holding buffer, the driving buffer, and the second holding buffer And a buffer control means for allocating cyclically,
Setting means for switching and setting the N drive patterns from the first to the Nth in a predetermined order in line units or pixel units of the display image of the video signal to be displayed;
When the video data of the same color as the N colored lights output in a time-sharing manner from the N light sources is C1, C2,..., CN, the line or pixel of the first drive pattern The video data C1 to CN are held in the first holding buffer, and the video data Cm to CN are stored in the first holding buffer in lines or pixels of the mth driving pattern (m is a natural number of 2 to N). Video data holding control means (151 to 153) for holding the video data C1 to Cm-1 in the second holding buffer and holding the video data in the holding buffer;
N color lights are emitted from the N light sources in a time-sharing manner, and the color lights emitted from the drive buffer assigned by the buffer control means in synchronization with switching and lighting of the N light sources. And a display element (104) that outputs the modulated color light supplied with the video data of the driving pattern set by the setting means according to the line or pixel of the display image to be driven An image display device characterized by that. The N is 3, and the three light sources are controlled to be turned on in a time-sharing manner every 1/3 frame period to output red light, green light and blue light in a time-sharing and cyclic manner, respectively. The setting means switches and sets the first, second and third drive patterns in a predetermined order in units of lines of display images of video signals to be displayed or in units of pixels.
The video data holding control means (153) outputs the primary color light from the three light sources in the order of the first primary color light, the second primary color light, and the third primary color light, and cyclically. , Out of the video signal to be displayed, C1 is video data of the same color as the first primary color light, C2 is video data of the same color as the second primary color light, and video data of the same color as the third primary color light. When C3 is set, the video data C1, C2, and C3 are held in the first holding buffer in the line or pixel of the first driving pattern, and the video data C2 is set in the line or pixel of the second driving pattern. And C3 are held in the first holding buffer, the video data C1 is held in the second holding buffer, and the video data C3 is stored in the first driving pattern line or pixel in the first holding buffer. Hold in the holding buffer The image display apparatus according to claim 1, wherein the holding of said video data C1 and C2 to the second holding buffer.