JP2011197389A - Video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To insert black data so as to increase the speed of response of a display element and display with high image quality by increasing a substantial frame rate above the effect of frame interpolation processing.SOLUTION: A liquid crystal display device 1 includes: a frame interpolation part exemplified by a double speed interpolation part 11; and a black data writing part and a position switching part exemplified by a black data insertion part 12. The frame interpolation part performs interpolation processing to video frames for interpolation between the frames and thereby makes the frame frequency n times (n is a natural number greater than one) as large as that before the interpolation. The black data writing part writes black data to a pixel that is approximately half of the frame after interpolation processing at the frame interpolation part. The position switching part switches the position of the pixel to which the black data is written at the black data writing part and the position of the pixel to which the video data is written as it is, every one frame.

Description

  The present invention relates to a hold-type video display device.

A hold-type video display device has a finite response speed, and a technique has been proposed in which the response speed is increased by inserting black data so that the viewer can visually recognize and improve the quality of moving images.
For example, the quality of moving images is improved by alternately displaying frames that display the entire screen in black by writing black data in a line sequential manner and frames that write image data in a line sequential manner.
Further, in the liquid crystal display device described in Patent Document 1, black data is inserted by alternately writing image data and blanking data to improve moving image quality.

JP 2003-36056 A

  However, this method not only has a problem that flicker is visually recognized, but also, for example, when video data having a frame period of 60 Hz is alternately displayed with image data and black data at a frame period of 120 Hz. When applied to display with a high, the video quality improvement effect was insufficient.

The present invention has been made in view of the above-described actual situation, and an object of the present invention is to insert black data so as to increase the response speed of the display element in a hold-type video display device, and to realize a substantial frame. The purpose is to increase the rate beyond the effect of the frame interpolation process and display it with high image quality.
Another object of the present invention is to insert black data so as to increase the response speed of the display element while suppressing flicker in a hold-type video display device, and to make the substantial frame rate more than the effect of frame interpolation processing. To display with high image quality.

  In order to solve the above-mentioned problem, a first technical means of the present invention is a hold-type video display device for displaying video data, interpolating between the video data and a frame frequency. Is a frame interpolation unit that multiplies n before interpolation (n is a natural number of 2 or more), a black data writing unit that writes black data to approximately half of the pixels after interpolation processing by the frame interpolation unit, and the black The data writing unit includes a position replacement unit that replaces the position of the pixel to which the black data is written and the position of the pixel in which the video data is written, for each frame.

  According to a second technical means, in the first technical means, the black data writing unit writes black data in a fringe pattern to the frame after interpolation processing by the frame interpolation unit. is there.

  According to a third technical means, in the first technical means, the black data writing unit writes black data in a checker pattern to the frame after the interpolation processing by the frame interpolation unit. is there.

  According to a fourth technical means, in any one of the first to third technical means, the black data writing unit sets the data voltage polarity at the time of writing the black data at the same frequency as the frame frequency of the frame before the interpolation. Or, it is characterized by alternating every frame.

According to one aspect of the present invention, in a hold-type video display device, black data is inserted so as to increase the response speed of the display element, and the substantial frame rate is increased beyond the effect of the frame interpolation processing to achieve high image quality. Can be displayed.
In addition, according to another embodiment of the present invention, it is possible to perform such display while suppressing flicker.

It is a block diagram which shows the example of 1 structure of the liquid crystal display device which concerns on this invention. It is a schematic diagram which shows the process example in the liquid crystal display device of FIG. It is a schematic diagram for comparing the process example of FIG. 2 with the conventional process example. It is a schematic diagram which shows the other process example in the liquid crystal display device of FIG. FIG. 5 is a schematic diagram for explaining a preferable voltage alternating frequency in the processing example of FIG. 2 or FIG. 4.

  The video display device according to the present invention is a video display device that performs hold-type display that keeps the applied voltage constant. Hereinafter, a liquid crystal display device will be described as an example of a hold-type video display device, but the present invention can also be applied to other hold-type video display devices such as organic EL (Electroluminescence).

  FIG. 1 is a block diagram showing an example of the configuration of a liquid crystal display device according to the present invention, in which 1 is a liquid crystal display device. The liquid crystal display device 1 includes a timing control circuit 13, a source driver 14, a gate driver 15, and a liquid crystal panel 16 as examples of a control unit and a display unit that display video data. The timing control circuit 13 is a circuit that controls the timing of the voltage applied to each of the source driver 14 and the gate driver 15.

  The liquid crystal display device 1 further includes a frame interpolation unit exemplified by the double speed interpolation unit 11. The frame interpolation unit performs an interpolating process for interpolating between the video data, thereby multiplying the frame frequency by n (n is a natural number of 2 or more) before interpolation. The double speed interpolation unit 11 is a configuration example in the case of n = 2. Hereinafter, a case where n = 2 will be described as an example, but this description is basically the same even when n is 3 or more.

  As the video frame that is the interpolation source, inter-field interpolation is performed if the frame of the image after intra-frame interpolation is performed as necessary, or if the input to the liquid crystal display device 1 is interlaced video data. This corresponds to a frame of the subsequent image, and at the stage of input to the double speed interpolation unit 11, pixel value data indicating video is present in the entire display range for each frame.

  As a main feature of the present invention, the liquid crystal display device 1 includes the following black data writing unit and position replacement unit. The black data writing unit writes black data to approximately half of the pixels after the interpolation processing by the double speed interpolation unit 11. The black data writing may be performed by rewriting the pixel value of the target pixel with a pixel value indicating black. Alternatively, blank data may be written, or a gain coefficient at a position where black data is finally written may be set to zero. Note that the black data write target is approximately half of the interpolated frame regardless of the value of n. The frame after the interpolation processing refers to a series of frames after the interpolation frame is inserted, and black data is written in approximately half of the pixels in each frame. Of course, it is preferable that the number of pixels is ½ of the interpolated frame, and this ideal example will be described below.

  The position replacement unit alternately replaces the position of the pixel to which the black data is written in the black data writing unit and the position of the pixel where the video data is written, every frame. Thus, the position replacement unit controls the writing position in the black data writing unit. In FIG. 1, the black data writing unit and the position replacement unit are mainly exemplified by a black data insertion unit 12 that writes black data while switching positions. Hereinafter, main control is performed by the black data insertion unit 12. Explain that.

  Thus, in the liquid crystal display device 1, for example, a video frame having a frame frequency of 60 Hz is subjected to double-speed video interpolation to 120 Hz, and after the interpolation processing, black data is written to 1/2 pixels of the screen (corresponding to). The black data writing pixel and the video data writing pixel are switched every frame (120 Hz) after the interpolation processing. Since the black insertion is performed on the video data after the frame interpolation process instead of the video data before the frame interpolation (black data insertion while switching the insertion position for each frame), the liquid crystal display device 1 has a response of the display element. Not only can the speed be increased to increase the substantial frame rate beyond the effect of frame interpolation, but it is also possible to display with high image quality.

  In addition, black data is inserted into half of the pixels of the frame, but black data and video data are interchanged. For example, the upper half of the screen is simply black data and the lower half is an image. When data is displayed so that the upper half of the screen is image data and the lower half is black data in the next frame, flicker is visually recognized. Therefore, it is preferable to take a countermeasure against flicker. In particular, since black data is written in the present invention, it is preferable to take a countermeasure such as making the pattern of the black data writing position finer. An example in which such measures are taken will be described with reference to FIGS. 2 and 3 and with reference to FIG.

  FIG. 2 is a schematic diagram showing a processing example in the liquid crystal display device of FIG. 1, and FIG. 3 is a schematic diagram for comparing the processing example of FIG. 2 with a conventional processing example. The black data insertion unit 12 preferably writes black data in a stripe pattern to the frame after the interpolation processing. The stripe pattern may be any pattern having a height or width of a predetermined size, and is a pattern in which black data and image data alternate for each line block of m lines, or for each column block of 1 column. There is a pattern in which black data and image data alternate. A more preferable former (horizontal stripe pattern) will be described as an example. Here, m is a natural number of 1 or more. In particular, since it is preferable to finely alternate black data and image data, m is preferably as small as possible, and it is most preferable to alternate every line (interlace).

  FIG. 2 shows an example of alternating every line. First, an interpolation frame 23 is generated by the double speed interpolation unit 11 for the video frames 21 and 22. Interpolation may be performed using, for example, an interpolation method. Of course, the interpolation is not limited to generating a frame between two frames, and an extrapolation method may be used.

  The black data insertion unit 12 inserts black data into the frames 21, 22, and 23 after the interpolation processing. With respect to the frame 21, black data is inserted into odd lines to form a frame 24. , Black data is inserted into even lines to form a frame 26, and for frame 22, black data is inserted into odd lines to form a frame 25. In frame 24, black data exists in odd lines 24b and original image data exists in even lines 24a, black data exists in even lines 26b and original image data exists in odd lines 26a in frame 26, and odd lines 25b exist in frame 25. In the above example, the original image data is present on the even-numbered line 25a. That is, black data may be inserted into even lines for frame 21, black data may be inserted into odd lines for frame 23, and black data may be inserted into even lines for frame 22. As described above, in the example of FIG. 2, the black data insertion unit 12 inserts black data for each line and switches the writing position of the black data for each frame.

  Thus, in the liquid crystal display device 1, for example, a video frame having a frame frequency of 60 Hz is subjected to double-speed video interpolation to 120 Hz, and after the interpolation processing, black data is written in a stripe pattern that is a half pixel of the screen, The black data writing pixel and the video data writing pixel are switched every frame (120 Hz) after the interpolation processing. This effect will be described with reference to FIG. In the liquid crystal display device 1 according to the present invention, as described in FIG. 2 and illustrated again in FIG. 3A, the frame interpolation processing from the frames 24 and 25 of 60 Hz to 120 Hz is performed, and the interpolation processing is performed. The black insertion is performed on the video data following the frames 24, 26 and 25.

  In the conventional method, as illustrated in FIG. 3B, when interlaced at 60 Hz, the frames 30 and 31 become the first field, the frames 32 and 33 become the second field, and the first field and the first field. The black data insertion position or blank data insertion position alternates between the two fields. Since the frame 31 is the same frame as the frame 30 and the difference in the position of the video (automobile in this example) with the frame 32 is larger than that in FIG. 3A, the method of FIG. In addition, since the black data insertion position is switched every 60 Hz, the flicker is somewhat conspicuous.

  Further, as illustrated in FIG. 3C, when the frames 34 and 36 are interlaced at 60 Hz to be the first and second fields, respectively, and then the frame 35 of the interpolated image is generated from the frames 34 and 36, The frame 35 is affected by the black data or blanking data and becomes a frame having a luminance value far from the original picture of the frames 34 and 36, the video is broken, and the black data insertion position is switched. Flicker is somewhat conspicuous because it is every 60 Hz. On the other hand, in the example of FIG. 3A, since black data is inserted after frame interpolation, there is no such concern.

  Further, as illustrated in FIG. 3D, when interlaced display is performed with 60 Hz without performing frame interpolation, the first field 37 of the first video, the second field 38 of the first video, and the first of the second video. It becomes like the field 39 and the second field 40 of the second video. In the second field 38 and 40, the position of the car is not moved compared to the first field 37 and 39, respectively, whereas in the next image, the position is not moved forward (right side in FIG. 3). Because it should not, the car will appear to be back, and the blur will be stronger. On the other hand, in the example of FIG. 3A, since black data is inserted after frame interpolation, there is no such concern.

  As described above, in the liquid crystal display device 1, compared to the conventional processing example, the response speed of the display element can be increased and the substantial frame rate can be increased beyond the effect of frame interpolation (equivalent to 240 Hz in the example of FIG. 2). Not only will this be possible, but it will also be possible to display with high image quality. Then, as described with reference to FIG. 2, by arranging the black data and the image data so as to have a line cycle, it is possible to increase the response speed of the display element while suppressing flicker as compared with the case where no flicker countermeasure is taken. The flicker is not visually recognized, and a significant moving image quality improvement effect is obtained.

  FIG. 4 is a schematic diagram showing another example of processing in the liquid crystal display device of FIG. An example in which black data is written for each line block composed of m lines has been described with reference to FIGS. 2 and 3, but the black data insertion unit 12 uses a checker pattern for a frame after interpolation processing by the frame interpolation unit. Black data may be written. Here, one square of the checker pattern may be a predetermined size, and this one square is preferably a small square with respect to the screen, such as a size of L pixels × L pixels. It may be rectangular. Here, L is a natural number of 1 or more, preferably L = 1.

  The example of FIG. 4 is an example of a checker pattern in which one square is a square. After the interpolation frame 43 is generated for the original video data of the frames 41 and 43, the black data insertion unit 12 inserts the black data. Yes. In the frame 41, black data is inserted into odd lines and odd columns (odd columns), odd lines and even columns 41a are left as they are, even lines and odd columns are left as they are, and black data is inserted into even lines and even columns 41b. Has been. On the other hand, in the frame 43, odd lines and odd columns are left as they are, black data is inserted into odd lines and even columns 43b, black data is inserted into even lines and odd columns, and even lines and even columns 43a are left as they are. ing. In the frame 42, black data is inserted into odd lines and odd columns, odd lines and even columns 42a are left as they are, even lines and odd columns are left as they are, and black data is inserted into even lines and even columns 42b. Yes. Of course, the black position in the checker pattern may be reversed. As described above, in the example of FIG. 4, the black data insertion unit 12 inserts the black data for each square to thereby write the black data into half the pixels of the screen in a checker pattern, that is, the black data. The insertion pattern is a checker pattern (houndstooth pattern), and the writing position of black data is switched for each frame.

  Thus, in the liquid crystal display device 1, for example, a video frame having a frame frequency of 60 Hz is subjected to double-speed video interpolation to 120 Hz, and after the interpolation processing, black data is obtained with a predetermined checker pattern that is a half pixel of the screen. The black data writing pixel and the video data writing pixel are switched every frame (120 Hz) after the writing and interpolation processing. Since black is inserted into the video data after the frame interpolation process, the liquid crystal display device 1 can only increase the response speed of the display element and increase the substantial frame rate beyond the effect of the frame interpolation. And display with high image quality. Then, as described with reference to FIG. 4, the black data and the image data are arranged so as to have a cycle of a predetermined pixel group (one square cycle). The response speed of the element can be increased, flicker is not visually recognized, and a significant moving image quality improvement effect is obtained. Although depending on the values of L and m, the example of FIG. 4 divides the black / image more finely than the example of FIG.

  Further, in the example described above, burn-in (afterimage feeling) due to image data writing is not considered, but it is preferable to take measures to prevent burn-in, and an example will be described with reference to FIG. FIG. 5 is a schematic diagram for explaining the frequency of the preferred voltage alternation in the processing example of FIG. 2 or FIG.

  Looking at the data polarity when paying attention to a certain pixel, in the case of normal driving in which the data polarity is inverted for each frame as illustrated in FIG. 5B, image data with the same polarity is always written and burn-in occurs. Will occur.

  Therefore, the black data writing unit sets the data voltage polarity when writing black data to the liquid crystal panel 16 (that is, when writing black data or image data) to the same frequency as the frame frequency of the frame before frame interpolation processing. Alternatively, it is preferable to alternate every frame. Note that such alternation of data polarity may be performed by controlling the source driver 14 and the gate driver 15 with the timing control circuit 13, for example. Here, the same frequency means alternating every 1 / n times the frame frequency after the frame interpolation process. For example, when the frame frequency before the frame interpolation process is 60 Hz, the data voltage polarity at the time of writing is alternated (inverted) every 60 Hz. In other words, in this example, a 60 Hz frame is subjected to interpolation processing to double the frame rate, black data is inserted, and line sequential writing is performed. At this time, when viewed in one pixel unit, frame unit (120 Hz) Thus, not only the black data and the pixel data are alternated, but also the data potential polarity of each pixel (in other words, the potential polarity of the black data) is inverted at a period of 60 Hz.

  In this way, by driving the polarity of the data voltage at the time of writing every 60 Hz, which is the same frequency as the frame frequency of the frame before the frame interpolation processing, as shown in FIG. Since the polarity of the image is inverted every frame, burn-in does not occur. In the present invention, since the writing position of black data is changed for each frame, the polarity of the data voltage during writing may be alternated for each frame. In this case as well, the example of FIG. 5A can be applied and burn-in can be prevented.

  Further, the example described with reference to FIG. 5 can be applied to both the processing example of FIG. 2 and the processing example of FIG. 4, and voltage alternation may be executed similarly. Further, in the example in which the voltage is alternated at the same frequency as the frame frequency of the frame before the frame interpolation processing, the position where the image is written even when the frame interpolation processing is 3 × speed or more (n is 3 or more) and n is an odd number. Such a voltage alternation has a certain effect because the polarities of the two are the same and the duration of the voltage becomes shorter.

  As described above, the video display device according to the present invention has been described by taking the liquid crystal display device 1 as an example. However, the liquid crystal display device is known to have a technique of applying overdrive in order to improve the response speed of the liquid crystal to the video signal. It has been. Although not described in detail, in the liquid crystal display device according to the present invention, since the frame rate is increased, it is preferable to apply overdrive in order to follow the response of the liquid crystal.

  The video display device according to the present invention is particularly useful for a device that employs an edge light system as a backlight in the case of a non-self-luminous video display device. This is a device that does not allow dimming for each area of the backlight, using an edge light system, and can improve the video performance by implementing pseudo impulse driving for each area using the backlight scanning technology. This is because the present invention can be suitably used to improve the moving image performance. Of course, the same moving image performance can be improved even with an apparatus other than the edge light system. The only difference is that in the case of the non-self-luminous and non-edge light type, the moving image performance can be substituted by the backlight scanning technique.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device, 11 ... Double speed interpolation part, 12 ... Black data insertion part, 13 ... Timing control circuit, 14 ... Source driver, 15 ... Gate driver, 16 ... Liquid crystal panel.

Claims (4)

  A hold-type video display device for displaying video data, which interpolates between the video data and interpolates between frames to increase the frame frequency by n (n is a natural number of 2 or more) before interpolation. , A black data writing unit for writing black data to approximately half of the pixels after the interpolation processing by the frame interpolation unit, and the position and video data of the pixel for writing black data in the black data writing unit An image display device comprising: a position replacement unit that replaces a position of a pixel as it is for each frame.   The video display device according to claim 1, wherein the black data writing unit writes black data in a stripe pattern to the frame after the interpolation processing by the frame interpolation unit.   The video display device according to claim 1, wherein the black data writing unit writes black data in a checker pattern to the frame after the interpolation processing by the frame interpolation unit.   The black data writing unit alternates the data voltage polarity when black data is written at the same frequency as the frame frequency of the frame before interpolation or every frame. The video display device according to claim 1.