JP2010055111A - Electro-optical device and image processing device, and electronic equipment - Google Patents

Abstract

Motion blur is reduced while maintaining image brightness.
An image signal processing circuit 170 performs dark display schematically shown by oblique lines in the drawing in subframes SFn2, SF (n + 1) 2, and SF (n + 2) 2. Accordingly, the pixel portion corresponding to the position of the edge Me of the moving object image M among the plurality of pixel portions 10p, or the pixel portions 10a arranged in a line in the image display region 10a, or the whole of the plurality of pixel portions 10a has low luminance. And a dark image will be displayed. By performing such dark display, the width W2 of the edge Me is relatively smaller than the width W1 of the edge Me when dark display is not performed. Therefore, the moving image blur can be reduced as the blur of the edge Me is reduced from the width W1 to the width W2.
[Selection] Figure 4

Description

  The present invention relates to a technical field of an electro-optical device such as a liquid crystal device, an image processing circuit applied to the electro-optical device, and an electronic apparatus such as a liquid crystal projector including the electro-optical device.

  In an electro-optical device such as a liquid crystal device that performs display in the hold mode, an afterimage in human vision is noticeable when displaying a moving image compared to a display device that performs display in an impulse mode such as a CRT (Cathode Ray Tube). In many cases, a moving image blur in which the edge of a moving object image appears blurred in a display image. Patent Document 1 discloses an example of a technique for reducing such moving image blur.

JP 2003-50569 A

  However, according to the technique disclosed in Patent Document 1, there is a problem that the entire display screen becomes dark, and moving image blur is reduced, but the brightness of each pixel that displays an image must be sacrificed. This causes technical problems.

  Therefore, the present invention has been made in view of the above problems, and an electro-optical device capable of reducing moving image blur without reducing the brightness of the entire image, and image processing applicable to such an electro-optical device. It is an object to provide a circuit and an electronic device.

  In order to solve the above problems, an electro-optical device according to the present invention displays a display unit having a plurality of pixel units constituting a display region on a substrate and the pixel unit based on an image signal in one frame. When the power luminance is the first luminance, the luminance of the pixel unit in one sub-frame obtained by dividing the one frame is set to a higher luminance than the first luminance, and the one frame is divided And an image signal processing circuit for generating an image signal for setting the luminance of the pixel unit in another subframe to a lower luminance lower than the first luminance.

  In the electro-optical device according to the present invention, the display unit is a liquid crystal panel in which a liquid crystal that is an example of an electro-optical material is sandwiched between a pair of substrates. Such a display portion includes a plurality of pixel portions each including an element such as a thin film transistor (TFT), a pixel electrode, and the like, and the plurality of pixel portions are arranged in a plane so that a display region is formed. Is configured.

  With the electro-optical device according to the present invention, for example, when a frame image corresponding to each of a plurality of frames constituting a series of frames for displaying a moving image is displayed at a frame period of 60 Hz, one frame is displayed. In each of the one subframe to be divided and the other subframe, a subframe image corresponding to each subframe is displayed. Such sub-frame images can be displayed by so-called double speed display.

  Here, when each frame image is displayed as it is in the display area, for example, the edge of the moving object image in the moving image displayed in the display area, that is, it is arranged at a position corresponding to the edge among a plurality of pixel portions. The luminance of the pixel portion that is present changes greatly between successive frames, resulting in motion blur. In order to reduce such a moving image blur, when a black image is displayed as a frame image to be displayed in one of the adjacent frames of the pixel portion, the luminance of the pixel portion is sacrificed, The brightness of the moving image constituted by the respective frame images of the frame is relatively lowered.

  Therefore, according to the electro-optical device according to the present invention, the image signal processing circuit, when the luminance to be displayed in the pixel unit based on the image signal in one frame is the first luminance, The luminance of the pixel unit in one divided sub-frame is set to a high luminance higher than the first luminance, and the luminance of the pixel unit in another sub-frame obtained by dividing the one frame is the first luminance. An image signal that is set to a lower luminance than that of the image signal is generated. In other words, unlike the conventional display method in which a black image is displayed in units of frames in order to reduce moving image blur, by displaying a low-brightness image lower than the first luminance in units of subframes, Make sure that the brightness of the displayed image does not decrease. Here, “high luminance” and “low luminance” are high or low luminance with reference to the first luminance that is the luminance of the pixel portion set according to the frame image that should be originally displayed in one frame. is there. Therefore, for example, when each period of one subframe and another subframe is set to ½ of the period of one frame, the luminance of the pixel portion in one subframe is set to high luminance, and the other By setting the luminance of the pixel portion in the sub-frame to a low luminance, the luminance of the pixel portion is averaged from the human eye for the entire period of one frame, and the brightness of the frame image is maintained.

  The image signal processing circuit generates an image signal corresponding to a subframe image to be displayed in each subframe based on various signals such as an image signal and a synchronization signal supplied corresponding to the frame period, and a liquid crystal panel or the like. To the display unit.

  As a result, not only the darkest image or black image that can be displayed in the display area, but also a dark image that is displayed according to a low luminance lower than the first luminance, such as dark gray or gray, can be displayed as long as the afterimage can be reduced. . Therefore, according to the image signal processing circuit, the pixel portion corresponding to the position of the edge of the moving object image described above in another subframe among the plurality of pixel portions, the pixel portion arranged in a line in the display region, or The entire plurality of pixel portions are set to low luminance, and a dark image is displayed. Such a dark image is displayed by the pixel portion in another subframe, so that moving image blur can be significantly reduced. More specifically, it is possible to reduce the width of the region where the luminance change of the pixel portion is interpolated by human eyes, that is, the width corresponding to the region that directly causes the moving image blur. .

  Therefore, according to the electro-optical device according to the present invention, even when the display operation is performed in the hold mode, the brightness of the moving image, which is difficult to solve by the conventional display method, and the reduction of moving image blur are reduced. Both of them are possible, and a moving image can be displayed with high quality.

  In one aspect of the electro-optical device according to the present invention, the image signal processing circuit stores each of the first luminance and the second luminance to be displayed in another frame succeeding or following the one frame. Means for comparing the first luminance and the second luminance stored in the storage means, and a determination means for determining whether or not a difference between the first luminance and the second luminance is equal to or greater than a predetermined threshold value. And the image signal processing circuit sets the high luminance and the low luminance for a predetermined pixel portion in which a difference between the first luminance and the second luminance is a predetermined threshold value or more among the plurality of pixel portions. By doing so, the image signal may be generated.

  According to this aspect, the storage unit is configured to obtain the luminance in each of the pixel unit constituting the predetermined region among the plurality of pixel units constituting the display region, each of the plurality of pixel units, or both in one frame and the other frame. Each of the first luminance and the second luminance is stored for a pixel portion set in advance so as to be acquired. Here, each of the first luminance and the second luminance is a luminance that the pixel unit should display in one frame and another frame when an image is displayed in units of frames. Correspondingly supplied image signals, that is, data corresponding to a voltage applied to an electro-optical material such as liquid crystal in accordance with the image signals are stored in a storage means including a frame memory.

  The determination unit determines whether or not the difference between the first luminance and the second luminance compared by the comparison unit is equal to or greater than a predetermined threshold value. Here, the “predetermined threshold value” is, for example, a reference value for determining whether or not moving image blur is visually recognized. For example, in a liquid crystal device, it is interposed between a pixel electrode and a counter electrode included in each pixel unit. An example is about 10% of the maximum value of the voltage applied to the liquid crystal. Of course, such a threshold can be set based on the type of liquid crystal as an example of the electro-optical material, that is, the relative relationship of the alignment state of the liquid crystal with respect to the applied voltage. In addition, it is possible to set the convenience in consideration of the allowable range of moving image blur, which is how much the moving image blur is reduced.

  The image signal processing circuit generates an image signal by setting high luminance and low luminance for a predetermined pixel portion in which a difference between the first luminance and the second luminance is equal to or greater than a predetermined threshold among the plurality of pixel portions. A pixel unit in which the difference between the first luminance and the second luminance is not less than a predetermined threshold among the plurality of pixel units displays the edge of the moving object image in the frame image displayed in each of the one frame and the other frame. By setting both high luminance and low luminance for such a pixel portion, moving image blur can be reduced while maintaining the luminance of the frame image.

  In another aspect of the electro-optical device according to the invention, the image signal supplied to the image signal processing circuit is an RGB color image signal, and the comparison unit includes R, G, and R included in the color image signal. It may be provided for each color component signal of B.

  According to this aspect, it is possible to reduce moving image blur that occurs in response to a change in luminance of specific color light among R (red), G (green), and B (blue). The comparison means compares the luminance (that is, the first luminance and the second luminance) of the pixel portion corresponding to each color component signal in one frame and the other frame. Therefore, according to this aspect, even when the luminance of the pixel unit corresponding to each color light changes for each frame, it is possible to reduce the occurrence of moving image blurring according to the change.

  In this aspect, when the difference between the first luminance and the second luminance relating to at least one color component signal of the R, G, and B color component signals is equal to or greater than a predetermined threshold, For all of R, G, and B, the high luminance and the low luminance may be set in the predetermined pixel portion.

  According to this aspect, moving image blur can be reduced, and high luminance and low luminance are set in a predetermined pixel unit for color light in which the difference between the first luminance and the second luminance is equal to or greater than a predetermined threshold, so that the image display area It is possible to reduce the occurrence of color shift in the displayed frame image.

  In another aspect of the electro-optical device according to the invention, only the color component signal in which a difference between the first luminance and the second luminance is equal to or greater than a predetermined threshold among the R, G, and B color component signals. The high luminance and the low luminance may be set in the pixel portion.

  According to this aspect, the moving image blur generated according to each frame image to be displayed over one frame and another frame can be reduced to a greater or lesser extent.

  In another aspect of the electro-optical device according to the invention, a difference between the first luminance and the second luminance relating to at least one color component signal of the R, G, and B color component signals is equal to or greater than a predetermined threshold. The image signal processing circuit may set the high luminance and the low luminance for the color component signals other than the one color component signal for the predetermined pixel portion.

  According to this aspect, it is possible to reduce moving image blur that occurs in accordance with a change in luminance of color light corresponding to another color component signal.

  In another aspect of the electro-optical device according to the invention, the image signal processing circuit stores the image signal of each of the frame image and a frame image to be displayed in another frame succeeding the one frame. A storage means; and a motion detection means for detecting a motion of a moving object image displayed in the display area by a series of frames including the one frame and the other frame based on the image signal, and the image signal processing. The circuit may generate the image signal for a pixel portion in which the movement of the moving object image is detected by the movement detecting unit among the plurality of pixel portions.

  According to this aspect, the motion detection unit can detect the motion of the moving object image in the frame image using, for example, an existing motion detection method. The image signal processing circuit generates an image signal for the pixel portion where the motion of the moving object image is detected based on the detection result detected by the motion detecting means (that is, the pixel portion corresponding to the edge of the moving object image). Thereby, moving image blur can be reduced as in the case of using the comparison means described above.

  In another aspect of the electro-optical device according to the present invention, the image signal processing circuit displays a corrected image signal obtained by correcting an image signal corresponding to each of the high luminance and the low luminance. The signal correction means for outputting to may be provided.

  According to this aspect, the signal correction unit can correct the image signal corresponding to each of the high luminance and the low luminance with reference to, for example, the gamma table. Thereby, the number of bits of the image signal can be reduced as compared with the case where the image signal is corrected by the image signal processing circuit.

  In order to solve the above problems, an image processing circuit according to the present invention is displayed on a display area of a display unit including a plurality of pixel units arranged on a substrate in the pixel unit based on an image signal in one frame. When the luminance to be obtained is the first luminance, the luminance of the pixel unit in one sub-frame obtained by dividing the one frame is set to a higher luminance than the first luminance, and the one frame is divided An image signal processing circuit for generating an image signal for setting the luminance of the pixel unit in the other subframe to a low luminance lower than the first luminance, and each of the one subframe and the other subframe. Driving means for driving the display unit in accordance with a corresponding image signal.

  According to the image processing circuit of the present invention, the driving means includes, for example, a scanning line driving circuit and a data line driving circuit that drive the display unit in accordance with image signals corresponding to both high luminance and low luminance. According to the image processing circuit of the present invention, it is possible to reduce motion blur as well as the electro-optical device described above, and to maintain the brightness of the frame image.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device of the present invention.

  According to the electronic apparatus according to the present invention, since the electro-optical device according to the present invention described above is provided, a projection display device, a mobile phone, an electronic notebook, a word processor, and a viewfinder type capable of high-quality display. Alternatively, various electronic devices such as a monitor direct-view video tape recorder, a workstation, a videophone, a POS terminal, and a touch panel can be realized. In addition, as an electronic apparatus according to the present invention, for example, an electrophoretic device such as electronic paper can be realized.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

1 is a block diagram of a liquid crystal device according to an embodiment of an electro-optical device according to the invention. It is an equivalent circuit of various elements and wirings in a plurality of pixel portions in the image display area. It is the conceptual diagram which showed the relationship between the frame image and sub-frame image which comprise a moving image. It is the figure which showed typically the brightness | luminance in the pixel part which comprises some image display areas. It is the figure which showed the comparative example corresponding to FIG. It is the figure which showed the combination of the brightness | luminance set to a pixel part in each sub-frame. FIG. 10 is a block diagram of a modification of the liquid crystal device according to an embodiment of the electro-optical device according to the invention. 1 is a plan view of a liquid crystal device according to an embodiment of an electro-optical device according to the invention. It is HH 'sectional drawing. It is sectional drawing showing the structure of the liquid crystal projector which concerns on one Embodiment of the electronic device which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the electro-optical device according to the present invention is applied to a liquid crystal device of a TFT active matrix driving type.

(Configuration and operation of electro-optical device)
First, with reference to FIG.1 and FIG.2, the structure and operation | movement which concern on the whole liquid crystal device 1 which concerns on this embodiment are demonstrated. FIG. 1 is a block diagram of the liquid crystal device 1, and FIG. 2 shows various elements, wirings, and the like in a plurality of pixel portions formed in a matrix constituting an image display region that is a display region of the liquid crystal device 1. It is an equivalent circuit.

  In FIG. 1, the liquid crystal device 1 includes a display unit 10c and an image signal processing circuit 170. The image signal processing circuit 170 includes a storage circuit 171, a determination circuit 172, a comparison circuit 173, and a correction circuit 174, and receives an image signal Si and a synchronization signal Ss from the video source 180. The display unit 10c includes a liquid crystal panel 100P, a scanning line driving circuit 104, and a data line driving circuit 101.

  The scanning line driving circuit 104 and the data line driving circuit 101 constitute an example of “driving means” in the image processing circuit according to the present invention, and the image signal processing circuit 170, the scanning line driving circuit 104, and the data line driving. The circuit 101 constitutes an example of an image processing circuit according to the present invention.

In FIG. 2, the liquid crystal panel 100p includes a plurality of pixel portions 10p arranged in a plane in a matrix in the image display area 10a. In the liquid crystal panel 100p, a pixel electrode 9a and a TFT 30 for switching control of the pixel electrode 9a are formed in each of the plurality of pixel portions. A data line 6 a to which an image signal is supplied is electrically connected to the source of the TFT 30. The image signals S1, S2,..., Sn to be written to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. May be.

  Further, the gate electrode is electrically connected to the gate of the TFT 30, and the scanning signals G1, G2,..., Gm are pulse-sequentially applied in this order to the scanning line 3a and the gate electrode at a predetermined timing. It is comprised so that it may apply. The pixel electrode 9a is electrically connected to the drain of the TFT 30, and the image signal S1, S2,... Supplied from the data line 6a is closed by closing the switch of the TFT 30 serving as a switching element for a certain period. Sn is written at a predetermined timing.

  A predetermined level of image signals S1, S2,..., Sn written in the liquid crystal as an example of the electro-optical material via the pixel electrode 9a is held for a certain period with the counter electrode formed on the counter substrate. The The liquid crystal modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. In the normally white mode, the transmittance for incident light is reduced according to the voltage applied in units of each pixel, and in the normally black mode, the light is incident according to the voltage applied in units of each pixel. The transmittance with respect to light is increased, and light having a contrast corresponding to an image signal is emitted from the liquid crystal device 1 as a whole.

  In order to prevent the image signal held here from leaking, a storage capacitor 70 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 9a and the counter electrode. The storage capacitor 70 is provided side by side with the scanning line 3a, and includes a fixed potential side capacitor electrode and a capacitor electrode 300 fixed at a constant potential.

In FIG. 1 again, the scanning line driving circuit 104 supplies the scanning signals G1, G2,..., Gm to the scanning line 3a at a predetermined timing as described above (see FIG. 2), and the data line driving circuit 101 is described above. As described above, the image signals S1, S2,..., Sn are supplied to the data line 6a at a predetermined timing (see FIG. 2). The data line driving circuit 101 includes, for example, a sampling circuit that samples the image signals S1, S2,..., Sn supplied on the image signal line, and a shift register that supplies a sampling pulse to the sampling circuit. It consists of

  The image signal processing circuit 170 performs scanning line driving on the scanning line driving circuit 104 based on the image signal Si and the synchronization signal Ss input from the video source 180 such as a DVD video player, a video recorder, or a video tuner. The scanning line driving circuit 104 is driven by supplying various signals Sc such as a reference clock signal (Y clock), an inverted clock signal, a start pulse signal (Y start pulse) serving as a reference for scanning, and a power supply signal. To do. Further, for the data line driving circuit 101, a clock signal (X clock) or an inverted clock signal that becomes a reference for driving the data line, a start pulse signal (X start pulse) that becomes a reference for starting scanning, for example, parallel-serial development. The data line driving circuit 101 is driven by supplying various signals such as image signals S1, S2,... Sj,. .

  Next, the operation of the liquid crystal device 1 will be described in detail with reference to FIGS. FIG. 3 is a conceptual diagram showing the relationship between frame images and subframe images that constitute a moving image displayed by the liquid crystal device 1. FIG. 4 is a diagram schematically showing luminance in a pixel portion constituting a part of the image display area 10a, and FIG. 5 is a schematic diagram showing a comparative example corresponding to FIG. FIG. 6 is a diagram schematically showing a combination of luminance in the pixel portion.

  As shown in FIGS. 1 and 3, the image signal processing circuit 170 is configured so that the display unit 10 c converts each of the frame images A, B,... To be displayed in each frame into two subframe images A1 and A2. .. Are divided into B1, B2,... So that the luminance integration of each sub-frame becomes the luminance of the image to be displayed in the original one frame. In the present embodiment, the display unit 10c double-speeds a frame image displayed at a frame period of 60 Hz based on the image signal Si and various signals Sc supplied from the image signal processing circuit 170, and at 1/2 frame. One subframe image is displayed. That is, the image signal processing circuit 170 outputs the image signal Si and the various signals Sc so that the display unit 10c can display the subframe image in each of the one subframe and the other subframe that time-divides one frame. It supplies to the display part 10c.

  More specifically, as shown in FIG. 3, the frame image A to be displayed in the image display area 10a in the nth frame is displayed as the subframe images A1 and A2 in the nth frame subframes SFn1 and SFn2, respectively. Is done. When the sub-frame image A2 is displayed, the luminance of the pixel unit 10p is lower than that of the pixel unit 10p when the frame image A is displayed (that is, the pixel unit 10p when the frame image A is displayed). Display relatively dark with respect to luminance). On the other hand, when the sub-frame image A1 is displayed, the luminance of the pixel unit 10p is higher than the luminance of the pixel unit 10p when the frame image A is displayed (that is, the pixel when the frame image A is displayed). Display is relatively bright with respect to the brightness of the part. In this way, a relatively dark image compared to the frame image to be displayed in one frame is displayed as a sub-frame image, so that the moving image blur is reduced as described later with reference to FIGS. Can be reduced. In addition, since the luminance of the pixel portion in each of the subframe images A1 and A2 is set to high luminance and low luminance, the pixel portion 10p in the nth frame in which the subframe images A1 and A2 are displayed. The brightness is averaged, and the brightness of the entire image display area 10a can be maintained at the same brightness as when one frame image A is displayed.

  Here, with reference to FIG. 4 and FIG. 5, the reason why it is possible to reduce the motion blur and maintain the brightness of the frame image in the liquid crystal device 1 will be described in detail. 4 and 5 exemplify a case where the moving object image M displayed in black in the moving image displayed in the image display area 10a moves from the left side to the right side in the drawing. In FIGS. 4 and 5, black display in the pixel portion is indicated by hatching with diagonal lines.

  As shown in FIG. 5, when a frame image is displayed in each of the nth frame, the (n + 1) th frame, the (n + 2) th frame,..., The edge Me of the moving object image M is It is defined by a stepped portion defined by the pixel portion 10p that is sequentially displayed black for each frame. Here, when the edge Me, which is a stepped portion defined by the pixel portion 10p displayed in black, is viewed with human eyes, the human eye interpolates the corners of the pixel portion 10p displayed in black. As a result, the edge Me appears to be blurred by the width W1 of the stepped portion as seen by human eyes. This width W1 is a direct cause of moving image blur.

  Therefore, as described in FIG. 3, the liquid crystal device 1 according to the present embodiment performs display with different luminance in the subframes that divide each frame. More specifically, high luminance display with higher luminance and lower luminance display with lower luminance than the luminance of the original image signal are performed within one frame.

  As shown in FIG. 4, the image signal processing circuit 170 divides one frame as two subframes each having a half frame as one subframe, and the pixels in one subframe period of the two subframes. The high luminance display is performed on the portion 10p, and the low luminance display is performed on the pixel portion 10p in the other subframe period. More specifically, an impulse-like display schematically shown by hatching in the drawing is performed on the subframes SFn2, SF (n + 1) 2, and SF (n + 2) 2. Therefore, the image signal processing circuit 170 includes a pixel portion corresponding to the position of the edge Me of the moving object image M among the plurality of pixel portions 10p, the pixel portions 10a arranged in a line in the image display region 10a, or a plurality of pixel portions 10p. The entire pixel unit 10a is set to low luminance, and the same effect as the black image insertion as in the prior art can be obtained on display.

  By performing such display, the width W2 of the edge Me is relatively smaller than the width W1 of the edge Me when display is not performed in units of subframes. Therefore, the moving image blur can be reduced as the blur of the edge Me is reduced from the width W1 to the width W2.

  In FIG. 4, the luminance of the pixel unit 10p that performs high-luminance display is higher than that in the case where the frame images A and B are not divided into the sub-frame images A1 and A2 and B1 and B2, respectively. Has been increased. On the other hand, the luminance of the pixel unit 10p that displays the sub-frame images A2 and B2 on which low luminance display is performed is relatively low compared to the luminance of the pixel unit 10p on which high luminance display is performed. Therefore, the average of the luminance of each pixel unit 10p in each frame period, that is, the luminance perceived by the human eye is maintained at the luminance when the original frame image is perceived by the human eye. Thereby, the brightness of the moving image displayed in the image display area 10a is maintained at the same brightness as when the frame is not divided.

  As described above, according to the liquid crystal device 1 according to the present embodiment, the black image display circuit 170 displays the frame images A, B,... To be displayed in one frame with predetermined brightness and frame units. One subframe that displays an image in units of subframes and divides one frame so that the image is displayed in the image display region 10a with the brightness of each frame image when the frame image is displayed in the region 10a In each of the other subframes, the luminance of the pixel unit 10p is set to high luminance and low luminance. Thereby, it is possible to prevent the brightness of the image displayed in the display area from being lowered as compared with the luminance of the original image signal. In addition, according to the liquid crystal device 1, the moving image blur can be remarkably reduced in the same manner as when a black image is inserted. More specifically, since it is possible to reduce the width of the region interpolated by the human eye among the regions where the luminance change of the pixel portion occurs, that is, the width corresponding to the region directly causing the moving image blur, Moving image blur can be reduced as much as this width is reduced.

  Therefore, according to the electro-optical device according to the present invention, even when the display operation is performed in the hold mode, the brightness of the moving image, which is difficult to solve by the conventional display method, and the reduction of moving image blur are reduced. Both of them are possible, and a moving image can be displayed with high quality.

  In addition, as will be described next, only the pixel portion 10p that defines the edge Me among the plurality of pixel portions 10p constituting the image display region 10a by the processing operation of each circuit included in the liquid crystal device 1 shown in FIG. A low-luminance display can also be performed. This case will be described in detail with reference to FIGS.

  1 and 3, the storage circuit 171 includes a first frame memory 171a and a second frame memory 171b. The second frame memory 171b acquires the image data of the frame image A to be displayed in the nth frame from the image signal Si and the synchronization signal Ss supplied from the video signal source 180, and temporarily stores them. Next, the first frame memory 171a acquires and stores the image data of the frame image B to be displayed in the (n + 1) th frame. Next, the comparison circuit 173 reads the image data of the nth frame and the image data of the (n + 1) th frame from the first frame memory 171a and the second frame memory 171b, respectively. The comparison circuit 173 compares the luminance in each of the nth frame and the (n + 1) th frame of the pixel unit 10p (that is, the luminance that is an example of each of the “first luminance” and the “second luminance” in the present invention). .

  As a result of the comparison by the comparison circuit 173, when the luminance difference between the nth frame and the (n + 1) th frame of the pixel unit 10p is, for example, 10% or more in the determination circuit 172, the black image display circuit 170 Data line driving is performed by using the image signals Sj1 and Sj2 obtained by adding a predetermined coefficient to the image signal Si included in the image data of each of the nth frame and the (n + 1) th frame as the image signals of the subframes SFn1 and SFn2. Supply to the circuit 101.

  More specifically, even when each frame image is displayed divided into subframe images, the frame image composed of these subframe images is the brightness of the frame image when a single frame image is displayed in each frame. The predetermined coefficient is set so as to be the same. For example, in this embodiment, the image signal Sj1 is obtained by adding 1.3 as a predetermined coefficient to the image signal Sj, and the image signal Sj2 is obtained by adding 0.7 as a predetermined coefficient to the image signal Sj. . Therefore, in the pixel unit 10p, the brightness obtained by averaging the brightness of the two sub-frame images is equivalent to the brightness when a single frame image is displayed. The brightness of the frame image is also increased in the (n + 1) th frame by displaying the subframe image with the image signal subjected to the same processing for the pixel unit that displays the two subframe images in the (n + 1) th frame. Maintained.

  In particular, as shown in FIG. 4, the nth frame and the nth frame of the plurality of pixel units 10p are used for the purpose of performing low luminance display only on the pixel unit 10p that defines the edge Me without displaying a black display in a line shape. By setting the high luminance and the low luminance for the pixel portion where the difference in luminance in each of the (n + 1) frames is equal to or greater than a predetermined threshold, the predetermined pixel portion is reduced in one of the two subframes dividing one frame. Display brightness. The predetermined pixel unit is a pixel unit that displays the edge Me of the moving object image M in the frame image displayed in each of the one frame and the other frame. The predetermined pixel unit has high luminance and low luminance, respectively. By setting, the width of the edge Me perceived by the human eye can be made smaller than when a single frame image is continuously displayed, and moving image blur can be reduced while maintaining the brightness of the moving image. . In addition, the amount of data stored in the storage circuit 171 can be reduced, and signal processing for image signals can be performed at high speed.

  The predetermined coefficient is set so that the lower luminance of two luminances having a difference equal to or larger than a predetermined threshold such as 10% is 1. Further, when the luminance exceeding the maximum luminance in the frame image is calculated by integrating a predetermined coefficient larger than 1 in the image signal, the image signal obtained by integrating the predetermined coefficient larger than 1 is The pixel portion is limited to display at the maximum luminance. Further, by adopting each of 0 and 2 as the predetermined coefficient, each of the two sub-frame images can be displayed by the pixel unit that performs high-luminance display and low-luminance display with a clear difference in luminance, and blur of the edge Me is displayed. And low luminance display can be performed only on the pixel portion corresponding to the edge Me. Here, the predetermined threshold is, for example, a reference value for determining whether or not moving image blur is visually recognized. For example, in a liquid crystal device, as described above, between the pixel electrode and the counter electrode included in each pixel unit. An example is about 10% of the maximum value of the voltage applied to the intervening liquid crystal. Of course, such a threshold can be set based on the type of liquid crystal as an example of the electro-optical material, that is, the relative relationship of the alignment state of the liquid crystal with respect to the applied voltage. In addition, the predetermined threshold is set in consideration of how much the moving image blur is reduced.

  The correction circuit 174 outputs corrected image signals Si1 and Si2 obtained by correcting image signals corresponding to high luminance and low luminance to the display unit 10c. According to the correction circuit 174, for example, an image signal corresponding to each of high luminance and low luminance can be corrected with reference to a gamma table. As a result, an image signal including a signal for displaying low luminance after the image signal that has been signal-processed according to the luminance to be displayed is generated in advance is generated in accordance with the corresponding subframe. The number of bits of the signal can be reduced.

  Next, with reference to FIG. 6, a combination of luminances set in the pixel portion in each subframe will be described. FIG. 6 illustrates an example in which the pixel unit 10p performs white display in the nth frame and performs low luminance display in the (n + 1) th frame. That is, the pixel unit 10p that performs high-luminance display and low-luminance display in each of the nth frame and the (n + 1) th frame is a pixel unit that displays the edge Me of the moving object image M.

  As shown in FIG. 6A, the pixel unit 10p that performs high-luminance display in the n-th frame performs display at higher luminance than the high-luminance display that should be displayed in the n-th frame in the subframe SFn1, and in subsequent SFn2 Low brightness display with low brightness. The pixel unit 10p that should have performed high display in the nth frame performs low luminance display in the (n + 1) th frame. Here, the pixel unit 10p performs low-luminance display in two subframes SF (n + 1) 1 and SF (n + 1) 2 that divide the (n + 1) th frame. Since the pixel unit 10p performs low-luminance display in the subframe SFn2, moving image blur visually recognized by the pixel unit 10p can be reduced.

  As shown in FIG. 6B, the pixel unit 10p that performs high-luminance display in the n-th frame performs display with the same luminance as the high-luminance display that should be displayed in the n-th frame in the subframes SFn1 and SFn2. The pixel unit 10p that performs high luminance display in the nth frame displays a dark display having a lower luminance than the low luminance display to be displayed in the (n + 1) th frame in the subframe SF (n + 1) 1. The pixel unit 10p performs display with the same luminance as the display to be displayed in the (n + 1) th frame in the subframe SF (n + 1) 1. In the subframe SF (n + 1) 1, the pixel unit 10p can display a moving image in which moving image blur is reduced similarly to the impulse mode display even when the hold mode display is performed by performing a darker display. .

  In FIG. 6C, the pixel unit 10p that performs high-luminance display in the n-th frame performs display with higher luminance than the display that should be displayed in the n-th frame in the subframe SFn1, and performs display with lower luminance in the subsequent SFn2. Do. The pixel unit 10p displays a dark display whose luminance is lower than that of the display to be displayed in the (n + 1) th frame in the subframe SF (n + 1) 1. The pixel unit 10p performs display with the same luminance as the display to be displayed in the (n + 1) th frame in the subframe SF (n + 1) 2. In the case where the pixel unit 10p performs hold mode display by performing display in the sub-frame SFn1 with higher brightness than the display to be displayed in the n-th frame and performing darker display in the sub-frame SF (n + 1) 1. Even so, a moving image with reduced moving image blur can be displayed as in the impulse mode display.

  As shown in FIGS. 6A to 6C, a plurality of display combinations in the subframe can be set.

  The liquid crystal device 1 is a display device capable of color display, and the image signal supplied from the video source 180 to the image signal processing circuit 170 is an RGB color image signal. The color component signal of the frame image of each frame stored in each of the frame memories 171a and 171b included in the storage circuit 171 is image data corresponding to the luminance of each color light of R (red), G (green), and B (blue). Is included. The comparison circuit 173 is provided for each of R, G, and B color component signals included in the color image signal. The storage circuit 171 stores, for example, each color component signal included in the image signal Si in each of the nth frame and the (n + 1) th frame. The comparison circuit 173 compares the luminance for each color to be displayed on the pixel unit 10p according to the color component signal stored in the storage circuit 171. Based on the comparison result of the comparison circuit 173, the determination circuit 172 causes the pixel unit 10p to apply the nth frame for a color component in which the luminance difference among the colors of R, G, and B is equal to or greater than a predetermined threshold. And at least one of the (n + 1) th frames, a dark display (that is, a luminance lower than the luminance that should have been originally displayed) is performed. Such dark display is also performed between the (n + 1) th frame and the (n + 2) th frame. That is, the image signal processing circuit 170 determines whether or not to make the pixel portion 10p display a dark image by comparing each color light of frame images that are continuously displayed.

  Therefore, even if the liquid crystal device 1 is a display device that can perform color display, according to the liquid crystal device 1, a change in luminance of specific color light among R (red), G (green), and B (blue) is performed. The moving image blur that occurs can be reduced.

  Further, the image signal processing circuit 170 relates to at least one color component signal of the R, G, and B color component signals, and displays frame images (for example, an nth frame and an (n + 1) th frame) that are displayed consecutively. In the case where the luminance of the pixel portion 10p in each of the frame images displayed in each of the pixel images 10p is greater than or equal to a predetermined threshold, the nth frame and A dark image may be displayed in a subframe of at least one of the (n + 1) th frames. As described above, with respect to the color light whose luminance difference is equal to or greater than the predetermined threshold value, dark display (that is, setting high luminance and low luminance) in the pixel portion can reduce moving image blur and color shift in the frame image. Can be reduced.

  It should be noted that the image signal processing circuit 170 has a color component signal having the difference only for the pixel portion in which the luminance difference in each successive frame among the R, G, and B color component signals is equal to or greater than a predetermined threshold. Only a dark display may be displayed. In this way, even if a dark display is performed only for a specific color component, moving image blur can be reduced to a greater or lesser extent.

  The image signal processing circuit 170 determines a threshold value for a pixel portion having a difference of a predetermined threshold value or more with respect to the luminance when the luminance difference is equal to or greater than a predetermined threshold value for at least one of the R, G, and B color component signals. Dark display may be performed on the pixel portion for other color component signals excluding the color component signals having the above luminance difference. In this way, it is possible to reduce moving image blurring that occurs in response to changes in the luminance of the color light corresponding to the other color component signals.

  (Modification) Next, a modification of the liquid crystal device 1 according to the present embodiment will be described with reference to FIG. FIG. 7 is a block diagram of the liquid crystal device 1 according to this example. In the following description, common reference numerals are assigned to portions common to the liquid crystal device 1 described above, and detailed description thereof is omitted.

  In FIG. 7, the image signal processing circuit 170 includes a storage circuit 171, a determination circuit 173, a motion detection circuit 183, and a correction circuit 174.

  The storage circuit 171 includes a first frame memory 171a and a second frame memory 171b, and these frame memories store image signals of a frame image and a frame image to be displayed in another frame that is in succession to one frame. Remember. More specifically, the first frame memory 171a and the second frame memory 171b store image signals in, for example, each of the nth frame and the (n + 1) th frame.

  The motion detection circuit 183 detects the motion of the moving object image M displayed in the image display area 10a by a series of frames including one frame and another frame based on the image signal stored in each frame memory. The motion detection circuit 183 detects the motion of the moving object image in the frame image using an existing motion detection method.

  The image signal processing circuit 170 displays a dark image on the pixel unit 10p in which the movement of the moving object image M is detected by the motion detection circuit 183 among the plurality of pixel units 10p. More specifically, in at least one of the consecutive frames, a dark image is displayed in one of the subframes constituting the one frame. Here, the pixel unit 10p that displays a dark image is a pixel unit corresponding to the edge of the moving object image M.

  According to the liquid crystal device 1 according to the present example, the same image display as in the impulse display mode can be performed and the moving image blur can be reduced similarly to the case where the above-described comparison unit is used. In addition, a decrease in luminance of the image display area 10a can be suppressed.

(Overall configuration of electro-optical device)
Next, the overall configuration of the liquid crystal device 1 according to the present embodiment will be described with reference to FIGS. 8 and 9. 8 is a plan view of the electro-optical device when the TFT array substrate is viewed from the side of the counter substrate together with each component formed thereon, and FIG. 9 is a cross-sectional view taken along line HH ′ of FIG. It is. Here, a liquid crystal device of a TFT active matrix driving method with a built-in driving circuit, which is an example of an electro-optical device, will be described as an example.

  8 and 9, in the liquid crystal device 1, the TFT array substrate 10 and the counter substrate 20 are disposed to face each other. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are provided with a sealing material 52 provided in a seal region positioned around the image display region 10a. Are bonded to each other.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. Further, in the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance (inter-substrate gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed. That is, the electro-optical device according to the present embodiment is suitable for a small and enlarged display for a projector light valve.

  A light-shielding frame light-shielding film 53 that defines the frame area of the image display area 10a is provided on the counter substrate 20 side in parallel with the inside of the seal area where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side. Of the peripheral region farther than the frame light-shielding film 53, the data line driving circuit 101 and the external circuit connection terminal 102 are provided on one side of the TFT array substrate 10 particularly in the region located outside the sealing region where the sealing material 52 is disposed. It is provided along. The scanning line driving circuit 104 is provided along two sides adjacent to the one side so as to be covered with the frame light shielding film 53. Further, in order to connect the two scanning line driving circuits 104 provided on both sides of the image display area 10a in this way, the TFT array substrate 10 is covered with the frame light shielding film 53 along the remaining side. A plurality of wirings 105 are provided.

  In addition, vertical conduction members 106 that function as vertical conduction terminals between the two substrates are disposed at the four corners of the counter substrate 20. On the other hand, the TFT array substrate 10 is provided with vertical conduction terminals in a region facing these corners. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20.

  In FIG. 9, on the TFT array substrate 10, an alignment film is formed on the pixel electrode 9a after the pixel switching TFT, the scanning line, the data line and the like are formed. On the other hand, on the counter substrate 20, in addition to the counter electrode 21, a lattice-shaped or striped light-shielding film 23 and an alignment film are formed on the uppermost layer portion. The liquid crystal layer 50 is made of, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed, and takes a predetermined alignment state between the pair of alignment films.

  On the TFT array substrate 10 shown in FIGS. 8 and 9, in addition to the data line driving circuit 101 and the scanning line driving circuit 104, the image signal on the image signal line is sampled and supplied to the data line. Sampling circuit, precharge circuit for supplying a precharge signal of a predetermined voltage level to a plurality of data lines in advance of an image signal, for inspecting the quality, defects, etc. of the electro-optical device during production or at the time of shipment An inspection circuit or the like may be formed.

(Electronics)
Next, a case where the above-described liquid crystal device 1 is applied to an electronic device will be described. Here, a projector using the liquid crystal device 1 as a light valve will be described. FIG. 10 is a plan view showing a configuration example of the projector.

  As shown in FIG. 10, a projector 1100 includes a lamp unit 1102 made of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide, and liquid crystal as a light valve corresponding to each primary color. Incident to devices 100R, 100B, and 100G. The configurations of the liquid crystal devices 100R, 100B, and 100G are the same as those of the above-described liquid crystal device, and R, G, and B primary color signals supplied from the image signal processing circuit are modulated in each. Light modulated by these liquid crystal devices is incident on the dichroic prism 1112 from three directions. In the dichroic prism 1112, R and B light is refracted at 90 degrees, while G light goes straight. As a result, the images of the respective colors are combined, and a color image is projected onto the screen 1120 and the like via the projection lens 1114.

  In the above, a liquid crystal device has been described as a specific example of the electro-optical device of the present invention. However, the electro-optical device of the present invention also uses an electrophoretic device such as electronic paper or an electron-emitting device. It can be realized as a display device (Field Emission Display and Surface-Conduction Electron-Emitter Display). In addition to the projector described above, the electro-optical device of the present invention includes a television receiver, a viewfinder type or a monitor direct-view type video tape recorder, a car navigation device, a pager, and an electronic notebook. It can be applied to various electronic devices such as a calculator, a word processor, a workstation, a video phone, a POS terminal, and a device having a touch panel.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and an electro-optical device with such a change, In addition, an image processing circuit and an electronic apparatus including such an electro-optical device are also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal device, 10c ... Display part, 170 ... Image signal processing circuit, 171 ... Memory circuit, 172 ... Determination circuit, 173 ... Comparison circuit, 174 ... Correction circuit 183, a motion detection circuit.

Claims (10)

A display unit having a plurality of pixel units constituting a display region on the substrate;
When the luminance to be displayed in the pixel unit based on the image signal in one frame is the first luminance, the luminance of the pixel unit in one sub-frame obtained by dividing the one frame is compared with the first luminance. An image signal processing circuit for generating an image signal that sets the brightness of the pixel unit in the other sub-frame obtained by dividing the one frame to a lower brightness than the first brightness. An electro-optical device comprising: The image signal processing circuit has storage means for storing each of the first luminance and the second luminance to be displayed in another frame that is adjacent to the one frame;
Comparison means for comparing the first luminance and the second luminance stored in the storage means;
Determining means for determining whether a difference between the first luminance and the second luminance is a predetermined threshold value or more;
The image signal processing circuit sets the high luminance and the low luminance for a predetermined pixel portion in which a difference between the first luminance and the second luminance is a predetermined threshold or more among the plurality of pixel portions, The electro-optical device according to claim 1, wherein the image signal is generated. The image signal supplied to the image signal processing circuit is an RGB color image signal,
The electro-optical device according to claim 2, wherein the comparison unit is provided for each of R, G, and B color component signals included in the color image signal. When the difference between the first luminance and the second luminance relating to at least one color component signal of the R, G, and B color component signals is equal to or greater than a predetermined threshold, the image signal processing circuit The electro-optical device according to claim 3, wherein the high luminance and the low luminance are set in the predetermined pixel portion for all of B. Of the R, G, and B color component signals, the high luminance and the low luminance are set in the predetermined pixel portion only for a color component signal in which a difference between the first luminance and the second luminance is a predetermined threshold value or more. The electro-optical device according to claim 3. When the difference between the first luminance and the second luminance relating to at least one color component signal of the R, G, and B color component signals is equal to or greater than a predetermined threshold, the image signal processing circuit is configured to output the predetermined pixel. The electro-optical device according to claim 3, wherein the high luminance and the low luminance are set for other color component signals excluding the one color component signal for the unit. The image signal processing circuit includes a storage unit that stores the image signals of the frame image and a frame image to be displayed in another frame that is adjacent to the one frame;
Motion detection means for detecting a motion of a moving object image displayed in the display area by a series of frames including the one frame and the other frame based on the image signal;
2. The electricity according to claim 1, wherein the black image display unit displays the black image on a pixel unit in which movement of the moving object image is detected by the motion detection unit among the plurality of pixel units. Optical device. The image signal processing circuit includes signal correction means for outputting a corrected image signal obtained by correcting an image signal corresponding to each of the high luminance and the low luminance to the display unit. The electro-optical device according to claim 1. When the luminance to be displayed on the pixel unit based on the image signal in one frame is the first luminance in the display area of the display unit including the plurality of pixel units arranged on the substrate, the one frame is The luminance of the pixel unit in one divided sub-frame is set to a high luminance higher than the first luminance, and the luminance of the pixel unit in another sub-frame obtained by dividing the one frame is the first luminance. An image signal processing circuit that generates an image signal that is set to a lower luminance than
An image processing circuit comprising: drive means for driving the display unit in accordance with image signals corresponding to the one subframe and the other subframe. An electronic apparatus comprising the electro-optical device according to claim 1.

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