JP2006345550A - Video display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain display resolved highly to be optimal to various kinds of pictures and to save power consumption by freely switching a method of pixel shifting according to a picture to display. <P>SOLUTION: The video display device is provided with a field memory 1 in which a video signal is written, a field memory control circuit 3 for controlling a quantity of writing data to the field memory 1 and a position of reading data from the field memory 1, a pixel shifting element control circuit 5 for shifting a display surface synchronizing with the operation of the field memory control circuit 3, and a moving picture judging circuit 2 for judging whether the video signal is a fast moving video or a slowly moving video. When the video signal is judged to be the slowly moving video by the moving picture judging circuit 2, the quantity of writing data and the position of reading data are controlled so as to make the video signal read from the field memory 1 have a field frequency which is integral multiple of the video signal written in the field memory 1, and the display surface is shifted by the pixel shifting element control circuit 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a video display device that forms, for example, one frame image by a plurality of field images, and shifts the observation position of the video step by step for each field to obtain a desired high-resolution video.

  2. Description of the Related Art Conventionally, in a video display device that shifts pixels, a ferroelectric liquid crystal (FLC) or an antiferroelectric liquid crystal (AFLC) having a high response speed is used as a display liquid crystal panel. Since these liquid crystals are driven by a simple matrix method, if the number of scanning lines increases or the number of pixel shifts increases and the number of rewrites increases, it takes time to rewrite one screen. As a result, the purpose of high resolution cannot be achieved.

  In view of this point, for example, Patent Document 1 has a display surface in which a plurality of pixels are arranged, and the video display control unit displays a video on substantially the entire display surface, and a partial area thereof. Displays the image by selectively shifting the image display position on the display surface by approximately an integral multiple of the pixel array pitch or approximately 1 / integer, and further, the image display control is performed by the display surface shift means. In synchronism with the operation of the means, the display surface is effectively shifted in the direction opposite to the shift direction of the video display position, so that a display element having a relatively large number of scans or a pixel is used. A technique relating to a video display device capable of effectively achieving high resolution even when the number of shifts is increased is disclosed.

  Here, the features of the conventional technique will be described in detail with reference to FIGS. As shown in FIG. 9, in the video display device, a liquid crystal display element (LCD) 105 is illuminated by a backlight 104 at a display unit 103, and two light beams from each pixel of the LCD 105 are emitted. After shifting through the pixel shifting elements 106 and 107, the light is made incident on the eyeball. The LCD 105 is, for example, a simple matrix drive type, and has an FLC or AFLC.

  The pixel shifting elements 106 and 107 are composed of liquid crystals 106a and 107a and birefringent elements 106b and 107b, respectively. The liquid crystals 106a and 107a have the property of changing the polarization direction of light according to the voltage, and the birefringence elements 106b and 107b have the property of shifting the light according to the polarization direction. Therefore, by applying a predetermined voltage to the pixel shifting elements 106 and 107 by the pixel shifting element driving circuit 102, a desired observation position can be freely selected from among the light beam positions P1, P2, and P3 shown in the figure. be able to.

In the video display device according to this prior art, the observation position of the pixel is changed by shifting the incident light beam by such a method, and the apparent number of pixels is increased.
Japanese Patent Laid-Open No. 9-322099 (Japanese Patent Application No. 8-157394)

  The object of the present invention is to make it possible to switch the pixel shifting method according to the image to be displayed, to obtain an optimally high resolution display for various images, and to reduce power consumption. is there.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a video display device having a display surface in which a plurality of pixels are arranged and displaying an image on the display surface based on a video signal. Effectively in synchronism with the operation of the control means for selectively shifting the image display position with respect to the display surface by either approximately an integral multiple of the pixel arrangement pitch or approximately 1 / integer. A pixel shift element control means for selectively shifting the display surface; and a moving picture determination means for determining whether the video signal is a fast moving picture or a slow moving picture, and the moving picture judging means. When the video signal is determined to be a slow moving image, the control means and the pixel shift element control means shift the pixel and the display surface, and the moving image determination means causes the video signal to move quickly. When it is determined that the image is characterized in that it does not shift the pixel to the display surface by the control means and the pixel shift element control means.

  The first aspect has the following effects. That is, in the first aspect of the present invention, in a video display device that has a display surface in which a plurality of pixels are arranged and displays a video on the display surface based on a video signal, the video display position with respect to the display surface However, the control means selectively shifts the pixel by either approximately an integral multiple of the pixel arrangement pitch or approximately 1 / integer, and in synchronism with the operation of the control means, the pixel shift control means effectively The display screen is selectively shifted, and the video determination unit determines whether the video signal is a fast motion video or a slow motion video, and the video signal is a slow motion video by the video determination unit. When it is determined that the pixel and the display surface are shifted by the control unit and the pixel shifting element control unit, the video signal is a fast moving image by the moving image determination unit. When the constant is not shifted and the pixel to the display surface by the control means and the pixel shift element control means.

  In order to achieve the above object, according to a second aspect of the present invention, there is provided a video display device having a display surface in which a plurality of pixels are arranged and displaying a video on the display surface based on a video signal. The video rewriting means for selectively rewriting the video displayed on the display surface for at least a partial area of the display surface, and the display surface is effectively selectively synchronized with the operation of the video rewriting means. Display surface shifting means for shifting, and moving image determining means for determining whether the video signal is a fast moving image or a slow moving image, and the moving image determining means causes the video signal to move slowly. When it is determined that the image is an image, the image on the display surface is rewritten by the image rewriting means, and the display surface is shifted by the display surface shifting means.

  The said 2nd aspect has the following effects. That is, in the second aspect of the present invention, in a video display device that has a display surface in which a plurality of pixels are arranged and displays a video on the display surface based on a video signal, the display is performed by the video rewriting means. The image displayed on the screen is selectively rewritten for at least a partial region of the display surface, and the display surface is effectively selectively synchronized with the operation of the image rewriting means by the display surface shifting means. When the moving image determining means determines whether the video signal is a fast moving video or a slow moving video, and the moving image determining means determines that the video signal is a slow moving video. The image on the display surface is rewritten by the image rewriting means, and the display surface is shifted by the display surface shifting means.

  In order to achieve the above object, a third aspect of the present invention is a video display device having a display surface in which a plurality of pixels are arranged and displaying a video on the display surface based on a video signal. And a field memory control for controlling the amount of data written to the field memory and the position of data read from the field memory so that the field frequency of the video signal is variable. Means, display surface shift means for selectively shifting the display surface in synchronism with the operation of the field memory control means, and the video signal is a fast motion video or a slow motion video. Moving image determining means for determining whether the video signal is a slowly moving image when the moving image determining means determines that the field The memory control means controls the write data amount and the read data position so that the video signal read from the field memory has a field frequency that is an integral multiple of the video signal written to the field memory. The display surface is rewritten and the display surface is shifted by the display surface shifting means.

  The third aspect has the following effects. That is, according to the third aspect of the present invention, there is provided a video display device that has a display surface in which a plurality of pixels are arranged and displays video on the display surface based on a video signal. A signal is written, and the amount of data written to the field memory and the position of data read from the field memory are controlled by the field memory control means so that the field frequency of the video signal is variable, and the display surface shift means Thus, the display surface is effectively shifted in synchronism with the operation of the field memory control means, and the moving picture determination means determines whether the video signal is a fast moving picture or a slow moving picture. When the moving image determining means determines that the video signal is a slow moving image, the field memory control means The video on the display surface is rewritten by controlling the write data amount and the read data position so that the video signal read from the field memory has a field frequency that is an integral multiple of the video signal written to the field memory. The display surface is shifted by the shift means.

  According to the present invention, there is provided a video display device capable of switching a pixel shifting method in accordance with an image to be displayed, obtaining an optimally high resolution display for various images, and suppressing power consumption. Can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a video display apparatus according to the first embodiment. In the figure, only the characteristic components among the components of the video display apparatus according to the present embodiment are shown, and the other components are not shown and described.

  In the figure, a video signal from a video source source (not shown) is branched into two and input to a field memory 1 and a moving image determination circuit 2 respectively. The moving image determination circuit 2 determines whether the input video signal is related to a fast moving image such as a moving image or a low moving image such as a still image. The determination result by the moving image determination circuit 2 is input to the subsequent field memory control circuit 3, LCD control circuit 4, and pixel shift element control circuit 5. The operations of the circuits 3 to 5 are changed based on the determination result as described later.

  The field memory control circuit 3 generates an address to be given to the field memory 1 and a control signal for controlling the field memory 1. That is, when the moving image determination circuit 2 determines that the video signal relates to a fast moving image, the field memory control circuit 3 writes data corresponding to the number of pixels of the LCD in the field memory 1. On the other hand, when the data in the field memory 1 is read out, the data is controlled so as to be read out to be the same as the input video signal. That is, as shown in FIG. 2, the output video signal (lower part of FIG. 2) has the same waveform as the input video signal (upper part of FIG. 2) and is delayed by one field.

  On the other hand, when the video determination circuit 2 determines that the video signal relates to a video with little motion, the field memory control circuit 3 outputs the output video signal as shown in FIG. The field memory 1 is controlled so that (the lower part of FIG. 3) has a field frequency three times that of the input video signal (upper part of FIG. 3). Further, the field memory control circuit 3 controls the field memory 1 so that data three times the number of pixels of the LCD is written. On the other hand, at the time of reading, as shown in FIG. 3, the field memory control circuit 3 reads data (3n + 0 column data; n is an integer) in the first field (pixel shift position 1). In the next field, the data of the triangular mark (3n + 1 column data; n is an integer) is read (corresponding to the pixel shift position 2), and in the next field, the data of the cross mark part ( The field memory 1 is controlled so that 3n + 2 columns of data (n is an integer) is read (corresponding to the pixel shift position 3).

  In other words, according to this, one field of the input video signal has a data amount three times the number of pixels of the LCD, and one field of the output video signal has data corresponding to the number of pixels of the LCD. There will be only quantity. Instead, the video signal output in the period of one field of the input video signal becomes three fields, and each has data in a different column.

  The LCD control circuit 4 generates a signal for controlling the LCD such as a scanning signal. That is, when the moving image determination circuit 2 determines that the video signal is related to a fast moving image, a control signal for instructing to display the normal video signal shown in FIG. 2 on the LCD is generated. To do. When the video determination circuit 2 determines that the video signal is related to the image with little motion, a control signal for instructing the LCD to display the triple-speed video signal shown in FIG. Is generated. The control signal generated in this way is output to an LCD (not shown).

  The pixel shift element control circuit 5 generates a signal to be output to the liquid crystal constituting a pixel shift element (not shown). When the moving image determining circuit 2 determines that the video signal is related to a fast moving image, a predetermined signal is given to control the pixel shifting element so as not to change the pixel shifting position.

  On the other hand, when it is determined by the moving image determination circuit 2 that the video signal relates to an image with little motion, the pixel shift position is synchronized with the field of the output video signal as shown in FIG. A signal instructing that the change is generated is provided to a pixel shift element (not shown). However, the phase of the video signal field and the pixel shift signal do not always match. That is, for example, as shown in FIG. 6, the pixel shift position may change in the middle of the field.

  As described above, in the video display device according to the first embodiment, when the video signal relates to a fast motion video, the pixel shift is not performed, and the video display device relates to a video with little motion. Performs pixel shifting. Since the video with fast motion does not care about the details due to the speed of the motion, there is no problem even with an image with low resolution without pixel shifting. In the case of an image with little movement, the details of the video are concerned, so pixel shifting is performed to increase the resolution. When the pixel shift is not performed, the sampling frequency of the video signal and the frequency of the control signal of the LCD can be lowered, so that there is an advantage that power consumption can be suppressed.

  Here, an improvement example of the video display device according to the first embodiment will be described. When using a video display device with a slow response speed, it is difficult to rewrite the video signal at a speed three times the frequency rate of the normal NTSC (National Television System Committee), PAL (Phase Alternation by Line color television), etc. . Therefore, the video signal is rewritten at a normal frequency rate even when pixel shifting is performed. That is, since the pixel shift is not performed for a fast moving image, the operation is exactly the same as described above. On the other hand, for a video with little motion, the field memory control circuit 3, the LCD control circuit 4, and the pixel shift element control circuit 5 are operated so that the output video signal and the pixel shift position are at the timing shown in FIG. .

  At this time, the field memory control circuit 3 controls the field memory 1 so that a data amount three times the number of pixels of the LCD is written. At the time of reading, the field memory control circuit 3 reads only one column of data (circled data) from the field memory 1 in three columns, and in the next field, it is adjacent to the column read first. The column data (triangle mark data) is read out, and the next field is controlled so that the next column data (cross mark data) is read out. Also, the LCD control circuit 4 has the same field frequency of the output video signal regardless of whether or not the pixel shift is performed. become. Further, as shown in FIG. 4, the pixel shift control circuit 5 generates a pixel shift signal so that the pixel shift position changes in synchronization with the field of the output video signal.

  According to the above operation, when a video display element with a slow response speed is used, it is possible to perform pixel shifting while maintaining the rewrite frequency rate of the LCD as normal. In addition, since the pixel shift is for a video with little movement, there is no problem even if the video rewriting speed drops slightly. As a result, when pixel shift is performed using a video display element with a slow response speed, high resolution can be achieved by shifting the pixel for each field when writing to the field memory. If sampling is performed with the phase shifted so as to correspond to the pixel shift position at a normal frequency rate, it is not necessary to write data three times the number of pixels of the LCD, so the capacity of the field memory 1 can be reduced. Further preferred.

  In addition, in the pixel shifting mode, in addition to lowering the field frequency, only a part of the slow motion may be shifted. Also, a plurality of pixel shifting portions may be provided. In such a case, a method of shifting the pixel between two places, the place with the least movement and the place with the next smallest movement, is conceivable.

  In the above description of the first embodiment, the description has been made with the two-time shift using two pixel shift elements. However, the present invention is not limited to this, and the same shift can be made once or three or more times. Of course, this can be said.

  As the moving image determination circuit 2, various methods for measuring a motion vector have been proposed in the past by Japanese Patent Publication No. 7-79474, etc., and any one of these methods is used to measure a motion vector. The determination may be made based on the magnitude of the vector. At this time, the criterion is the speed at which a spatial frequency higher than the spatial frequency that can be displayed without pixel shifting is not recognized. No matter how many pixel shifts, there is no meaning because the movement is fast and the details are not recognized, but in fact, following an object moving with the eye will actually slow down, so it will be the reference It is better to switch with / without pixel shift at a speed slightly faster than the speed.

  Next, a second embodiment will be described. FIG. 5 is a diagram showing a configuration of a video display apparatus according to the second embodiment. In the figure, only the characteristic components among the components of the video display apparatus according to the present embodiment are shown, and the other components are not shown and described.

  In the figure, a video signal from a video source source (not shown) is branched into three and input to a field memory 1, a uniformity determination circuit 6, and a spatial frequency detection circuit 7 in the subsequent stage. The uniformity determination circuit 6 is a circuit that determines whether the spatial frequency of the entire image is uniform or only a part of the spatial frequency is high, and the determination result is the field memory control circuit 3 and the LCD control circuit in the subsequent stage. 4 and input to the pixel shift element control circuit 5, respectively. The spatial frequency detection circuit 7 detects a row having a high spatial frequency of the video signal, and the detection result is similarly sent to the field memory control circuit 3, the LCD control circuit 4, and the pixel shift element control circuit 5 in the subsequent stage. Each is entered.

  The operation of each circuit of the field memory control circuit 3, the LCD control circuit 4, and the pixel shift element control circuit 5 is changed as described later according to the determination result of the uniformity determination circuit 6 and the detection result of the spatial frequency detection circuit 7. Is done.

  When the uniformity determining circuit 6 determines that the spatial frequency of the entire screen is uniform, normal display is performed without pixel shifting. In this case, the operations of the field memory control circuit 3, the LCD control circuit 4, and the pixel shift element control circuit 5 are the same as those in the case of not performing the pixel shift of the first embodiment.

  On the other hand, when the uniformity determination circuit 6 determines that only a part of the image has a high spatial frequency, pixel shift is performed as follows. That is, when pixel shifting is performed, each circuit operates so as to shift pixels by a part of some rows before and after the row detected by the spatial frequency detection circuit 7.

  As shown in FIG. 6, the field memory control circuit 3 controls the field memory 1 so that three fields are output during one field of the input video signal. That is, in the field memory control circuit 3, the first field of the output video signal has data for all the rows of one field of the input video signal, and the next field of the output video signal is a partial row for pixel shifting. And the next field is controlled so as to have data of a part of the rows shifted by pixels. Further, control is performed so that the first field has column data in the (3n + 0) column, the second field has data in the (3n + 1) column, and the third field has data in the (3n + 2) column. .

  The row for pixel shifting is determined by the detection result of the spatial frequency detection circuit 7. For example, if the pixel shift range is L rows and the result of the spatial frequency detection circuit 7 is x rows, pixel shift is performed in the range from x−L / 2 rows to x + L / 2 rows. The range L is a predetermined value and is determined based on the response speed of the video display element. The range L increases when the response speed is fast and decreases when the response speed is slow.

  The LCD control circuit 4 generates a scanning signal or the like so that the output video signal shown in FIG. 6 is displayed on an LCD (not shown). That is, in the first field, scanning line signals are sequentially applied to all rows, and in the second and third fields, scanning signals are sequentially applied from the xL / 2 row to the x + L / 2 rows.

  The pixel shift element control circuit 5 generates a pixel shift signal so that the shift position changes at the timing shown in FIG. As described above with reference to the prior art, it is better to shift the pixel position when rewriting the data of the row that is desired to have the highest resolution. Therefore, as shown in FIG. 6, the pixel shift position is switched in the middle of each field of the output video signal. That is, when the x row obtained by the spatial frequency detection circuit 7 is rewritten, the pixel shift position is switched.

  As described above, in the second embodiment, by operating each circuit as described above, in the case of an image having a partially high spatial frequency, the high spatial frequency portion is subjected to high resolution by pixel shifting. Is displayed. In addition, an image having a uniform spatial frequency as a whole, such as a text screen, has a high resolution only and does not give an uncomfortable feeling.

  Further, in the case of performing partial pixel shifting, in particular, in the case where the pixel shifting portion is shifted not only in part but also in the two places with the highest spatial frequency and the second highest spatial frequency, It is necessary to make the total number of rows shifted by two pixels the same as in the case of one. Therefore, if the number of rows is increased, the scanning speed must be increased.

  In the second embodiment, since the image is generated while being scanned horizontally, the uniformity determination circuit 6 may compare the spatial frequency spectrum of each row. That is, first, each row is Fourier-transformed to obtain a spatial frequency spectrum. Next, the correlation of the spectral pattern with the adjacent row is obtained. Subsequently, the uniformity is judged from the way of changing the correlation thus obtained, and the pixel shift portion is determined. In the case of an image having a uniform spatial frequency, the spectral patterns in each row have the same shape, and thus all the correlations are large values.

  If there is a part where rows with high spatial frequency are gathered, the correlation becomes small at the boundary between high and low spatial frequencies. Therefore, it is divided into several groups with a small correlation as a boundary, the spectral patterns are compared for each group, and the range of the group having a large high spatial frequency portion is shifted by pixels.

  This criterion is based on how many rows of a group having a high spatial frequency component are larger than the number of rows in which pixel shifting is set in advance. If the number of rows in the group is a group of rows up to about twice as many as the number of rows to be shifted, some pixels are shifted. It should be noted that the uniformity determination method is not limited to this method, and it is needless to say that various other methods can be adopted. Of course, it is better if the reference can be changed depending on the display target.

  Next, a third embodiment will be described. FIG. 7 is a diagram showing the configuration of the video display apparatus according to the third embodiment. In the figure, only the characteristic components among the components of the video display apparatus according to the present embodiment are shown, and the other components are not shown and described. In addition, since the determination method and the reference of the moving image determination circuit 2 and the uniformity determination circuit 6 are the same as those in the first and second embodiments described above, the description thereof is omitted here.

  In the figure, a video signal from a video source source (not shown) is branched into four and input to a frame memory 1, a moving image determination circuit 2, a uniformity determination circuit 6, and a spatial frequency detection circuit 7, respectively. . The operations of the moving image determination circuit 2, the uniformity determination circuit 6, and the spatial frequency detection circuit 7 are the same as those in the first and second embodiments. The results of the moving image determination circuit 2 and the uniformity determination circuit 6 are input to the pixel shift mode determination circuit 9.

  The pixel shift mode determination circuit 9 selects one of the three pixel shift modes based on the results of the moving image determination circuit 2 and the uniformity determination circuit 6. Here, the three pixel shifting modes are “a mode without pixel shifting”, “a whole pixel shifting mode”, and “a partial pixel shifting mode”. The result determined by the pixel shift mode determination circuit 9 is given to each circuit of the field memory control circuit 3, the LCD control circuit 4, and the pixel shift element control circuit 5. Each circuit operates so as to be displayed in the mode determined by the pixel shift mode determination circuit 9. In the non-pixel shift mode and the full pixel shift mode, the same operations as those described in the first embodiment are performed.

  On the other hand, in the partial pixel shift mode, similarly to the description of the second embodiment, the pixel shift line is determined based on the result of the spatial frequency detection circuit 7, and the pixel shift is partially performed. As described above, the operation of each circuit is the same as that of the first and second embodiments, and therefore, the operation of the pixel shift mode determination circuit 9 will be mainly described here.

  Here, FIG. 8 is a flowchart showing a method for determining the pixel shift mode. First, the result of the uniformity determination circuit 6 is determined (step S1). If the result of the uniformity determination circuit 6 is a screen with a partial high spatial frequency, the partial pixel shift mode is immediately determined (step S2). If the spatial frequency of the entire screen is not uniform because there is a part where the spatial frequency is high, the result of the moving image determination circuit 2 is further determined (step S3). If the result of the moving image determination circuit 2 is a video with fast motion, the mode without pixel shift is determined (step S4). On the other hand, in the case of an image with no fast movement and little movement, the full screen shift mode is determined (step S5).

  As described above, in the third embodiment, since uniformity is determined first, the entire screen is not shifted by a part of the pixel with respect to a uniform screen, so that it does not give a sense of incongruity. . Further, by not performing pixel shifting for images that move quickly and cannot be seen in detail, the frequency of the video signal and the LCD control signal can be kept low, and the power consumption can be reduced.

  Further, in the full screen shift mode, similarly to the first embodiment, if pixels are shifted at a normal frequency rate, it is possible to deal with a display element with a slow response speed. In addition, the partial pixel shifting mode may be shifted twice, and the entire pixel shifting may be shifted once. Also in this case, there are two possible modes for the full-screen pixel shifting mode: a double speed rate and a normal frequency rate. In the partial pixel shift mode, a plurality of pixel shift portions may be provided.

  The embodiment of the present invention has been described above, but the present invention is not limited to this, and it is needless to say that various improvements and changes can be made without departing from the spirit of the present invention. For example, in the above embodiment, the display surface of the LCD is optically shifted using the pixel shifting element, but the display surface itself, that is, the LCD itself is shifted using, for example, a piezoelectric element or the like. May be. Of course, the present invention can also be applied to an image obtained by observing an image on a display surface such as an HMD through an eyepiece optical system.

In addition, the following invention is contained in the said embodiment of this invention.
(1) A video display device that has a display surface in which a plurality of pixels are arranged and displays a video on the display surface based on a video signal, and displays the video displayed on the display surface on the display surface Video rewriting means for selectively rewriting at least a part of the display area, display surface shifting means for selectively shifting the display surface in synchronism with the operation of the video rewriting means, Video judging means for judging whether the video is fast or slow moving, and the video rewriting is performed when the video judging means judges that the video signal is slow moving video. An image display device, wherein the display screen image is rewritten by the means, and the display surface is shifted by the display surface shift means.
(2) When the video determination unit determines that the video signal is a slow moving image, the video rewriting unit rewrites the video on the display surface at the same period as the field period of the input video signal. The video display device according to (1), wherein the display surface is shifted by the display surface shifting means.
(3) The moving image determining means further includes means for specifying a slow moving part of the video signal, and when the moving image determining means determines that the video signal is a slow moving image, The video display device according to (1), wherein the video of a partial area corresponding to the slow-moving portion of the display surface is rewritten by the rewriting means.
(4) A video display device that has a display surface in which a plurality of pixels are arranged and displays video on the display surface based on a video signal, and selectively rewrites the video displayed on the display surface. Video rewriting means, display surface shifting means for effectively shifting the display surface in synchronism with the operation of the video rewriting means, and the spatial frequency of the video signal being uniform or partially Uniformity determining means for determining whether the image signal is high, and when the spatial frequency of the video signal is determined to be partially high by the uniformity determining means, An image display apparatus, wherein an image of a partial region corresponding to a portion having a high spatial frequency on a display surface is rewritten, and the display surface is shifted by the display surface shift means.
(5) A video display device that has a display surface in which a plurality of pixels are arranged and displays a video on the display surface based on a video signal, and selectively rewrites the video displayed on the display surface. Video rewriting means, display surface shifting means for selectively shifting the display surface in synchronization with the operation of the video rewriting means, and the video signal is a fast moving video or a slow moving video. Moving image determining means for determining whether there is a video image, and uniformity determining means for determining whether the spatial frequency of the video signal is entirely uniform or partially high. When the determining means determines that the video signal is a slow moving image and the uniformity determining means determines that the spatial frequency of the video signal is generally uniform, the video rewriting means The entire display surface The display screen is shifted by the display screen shifting means, and the spatial frequency of the video signal is partially reduced by the uniformity determining means regardless of the determination result of the moving image determining means. When it is determined that the image is high, the image rewriting means rewrites the image of the partial area corresponding to the high spatial frequency portion of the display surface, and the display surface shift means shifts the display surface. A video display device characterized by the above.
(6) When the moving image determining means determines that the video signal is a slow moving image and the uniformity determining means determines that the spatial frequency of the video signal is generally uniform The video rewriting means rewrites the image of the entire area of the display surface at the same period as the field period of the input video signal, and the display surface shift means shifts the display surface ( The video display device according to 5).
(7) The video display device according to (1), (4), or (5), wherein the partial area is separated into a plurality of areas on the display surface.
(8) The display surface shifting means is for selectively shifting only one of approximately an integral multiple of the pixel arrangement pitch or approximately 1 / integer. Or the video display apparatus as described in (5).

  According to the second to sixth aspects, by determining whether or not to shift the pixel based on whether or not the video signal includes a fast motion, the pixel shift is performed for an image whose motion is fast and invisible to a fine place. Therefore, the driving frequency of the video display element can be kept low, and the power consumption can be reduced. Furthermore, it can be used even if it is not a display element with a fast response speed.

  According to the above (4), (7), and (8), it is determined whether or not to shift some pixels based on whether or not the entire surface is an image having uniform resolution. In other words, since a part of the pixels is shifted only for an image with uniform resolution on the entire surface, there is no sense of incongruity.

  According to the above (5) to (11), the pixel shift is determined based on whether or not the entire surface is an image with uniform resolution and whether or not the video signal includes fast motion. That is, some pixels are shifted for images with uniform resolution on the entire surface, so there is no sense of incongruity, and pixels are not shifted for images that move quickly and cannot be seen in detail. The driving frequency of the element can be kept low, and the power consumption can be reduced. Further, the display element can be used even if it is not a display element with a very fast response speed.

It is a figure which shows the structure of the video display apparatus which concerns on 1st Embodiment. It is a figure which shows the relationship between an input video signal and an output video signal. It is a figure which shows the relationship between the input video signal and output video signal in the case of controlling so that the data of 3 times the pixel number of LCD are written in the field memory 1. FIG. It is a figure which shows the relationship between the input video signal and output video signal in the case of using a video display element with a slow response speed. It is a figure which shows the structure of the video display apparatus which concerns on 2nd Embodiment. It is a figure which shows the relationship between an input video signal and an output video signal. It is a figure which shows the structure of the video display apparatus which concerns on 3rd Embodiment. It is a flowchart which shows the determination method of pixel shift mode. It is a figure which shows the structure of the video display apparatus concerning a prior art. It is a figure which shows the image rewriting part of LCD in the video display apparatus based on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Field memory 2 Movie determination circuit 3 Field memory control circuit 4 LCD control circuit 5 Pixel shift element control circuit

Claims (7)

In a video display device having a display surface in which a plurality of pixels are arranged and displaying a video on the display surface based on a video signal,
Control means for selectively shifting the image display position with respect to the display surface by either approximately an integer multiple of the pixel arrangement pitch or approximately 1 / integer.
Pixel shift element control means for selectively shifting the display surface in synchronism with the operation of the control means;
A moving image determination means for determining whether the video signal is a fast moving video or a slow moving video;
Comprising
When the moving image determining means determines that the video signal is a slow moving image, the control means and the pixel shifting element control means shift the pixel and the display surface, and the moving image determining means An image display device characterized in that, when it is determined that the image is fast moving, the pixel and the display surface are not shifted by the control means and the pixel shifting element control means. In a video display device having a display surface in which a plurality of pixels are arranged and displaying a video on the display surface based on a video signal,
Video rewriting means for selectively rewriting the video displayed on the display surface for at least a partial region of the display surface;
Display surface shifting means for effectively shifting the display surface in synchronism with the operation of the video rewriting means;
A moving image determination means for determining whether the video signal is a fast moving video or a slow moving video;
Comprising
When the video determination means determines that the video signal is a slow moving video, the video on the display surface is rewritten by the video rewriting means, and the display surface is shifted by the display surface shifting means. A video display device.   When the moving image determining means determines that the video signal is a slow moving image, the video rewriting means rewrites the video on the display surface at the same period as the field period of the input video signal, 3. The video display device according to claim 2, wherein the display surface is shifted by the display surface shifting means. The moving image determining means further includes means for specifying a slow moving part of the video signal,
When the moving image determining means determines that the video signal is a slow moving video, the video rewriting means rewrites a video of a partial area corresponding to the slow moving portion of the display surface. The video display device according to claim 2.   The video display device according to claim 2, wherein the partial area is separated into a plurality of areas on the display surface.   3. The video display device according to claim 2, wherein the display surface shift means selectively shifts the display surface by only approximately an integral multiple of the pixel arrangement pitch or approximately 1 / integer. A video display device having a display surface formed by arranging a plurality of pixels and displaying video on the display surface based on a video signal,
A field memory in which the video signal is written;
Field memory control means for controlling the amount of data written to the field memory and the position of read data from the field memory so that the field frequency of the video signal is variable;
Display surface shifting means for effectively shifting the display surface in synchronism with the operation of the field memory control means;
A moving image determination means for determining whether the video signal is a fast moving video or a slow moving video;
And the video signal read from the field memory by the field memory control means is written to the field memory when the video determination means determines that the video signal is a slow moving video. The display data is rewritten by controlling the write data amount and the read data position so that the field frequency is an integral multiple of the display frequency, and the display screen is shifted by the display screen shift means. apparatus.

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