JP4075941B2 - Image display device - Google Patents

Description

   In particular, the present invention relates to an image display device that displays image data on an image display unit including a display pixel array.

Hereinafter, the prior art will be described with reference to FIGS. 8 and 9. FIG. FIG. 8 shows a first conventional example of an image display device according to the prior art.
The image data generation device 81 is connected to a data communication line for supplying compressed image information and a CD-ROM 34 which is a database. The image data generated by the image data generation device 81 is image data writing means. Are sequentially input to the liquid crystal driver 82. The liquid crystal driver 82 transfers the image data to the TFT liquid crystal panel 84 constituted by a pixel array. A shift register 83 is provided at the end of the TFT panel 84.

Next, the operation of the first conventional example will be described. In response to a request from the image data generation apparatus 81, image information compressed in accordance with the MPEG1 standard is supplied to the image data generation apparatus 81 from the communication line or the CD-ROM 34. The image data generation device 81 sequentially inputs image data for each frame to the liquid crystal driver 82. The liquid crystal driver 82 inputs image data for one horizontal pixel at a time to the TFT liquid crystal panel 84 every time image data for one horizontal pixel is accumulated. At this time, the shift register 83 sequentially designates rows on the pixel array to which the image data is input.
An image display device having such a TFT liquid crystal display is disclosed in the Institute of Electronics, Information and Communication Engineers, Vol. 78 No. 7 pp662-667, July 1995 and the like.

  FIG. 9 shows a second conventional example of an image display device according to the prior art. The image data generation device 91 is connected to a data communication line for supplying compressed image information and a CD-ROM 34 which is a database. The image data generated by the image data generation device 91 is image data writing means. Is input to the liquid crystal driver 92. The liquid crystal driver 92 transfers the image data to the ferroelectric liquid crystal panel 94 constituted by a pixel array. A decoder 93 is provided at the end of the ferroelectric liquid crystal panel 94.

Next, the operation of the second conventional example will be described. In response to a request from the image data generation apparatus 91, image information compressed in accordance with the MPEG1 standard is supplied to the image data generation apparatus 91 from the communication line or the CD-ROM 34. The image data generation device 91 inputs, to the liquid crystal driver 92, image data of only a line including a portion changed from the previous frame (herein, this is referred to as a moving image portion) as rewritten partial image data. The liquid crystal driver 92 inputs image data for one horizontal pixel at a time to the ferroelectric liquid crystal panel 94 every time image data for one horizontal pixel (one row) is accumulated. At this time, the decoder 93 designates a row on the pixel array to which the image data is to be input.
In the still image portion, the previous rewritten image data is stored using the storage function of the ferroelectric liquid crystal.

An image display device having such a ferroelectric liquid crystal display is described in the IEICE Journal.
Vol. 78 No. 7 pp676-679 July 1995 and the like.

   In the first conventional example, the rewrite operation of all the display pixels is performed for each frame. This is because the number of display pixels is as small as, for example, about 640 × 480, so that there was no great difficulty. However, in order to realize a high-quality image display apparatus having the number of display pixels of about several thousand × several thousands, the rewrite operation of the first conventional example is performed because the rewrite speed of the display pixels is increased by one digit. It is difficult to realize using

The second conventional example uses the memory function of the ferroelectric liquid crystal to reduce the number of rewrites in one frame and to reduce the rewrite amount per unit time. However, in practice, ferroelectric liquid crystals are essentially difficult to memorize multi-levels and cannot store full-color still images. Therefore, in order to display a full-color still image, it is necessary to rewrite every frame, and the second conventional example has a problem of the rewriting speed of the display pixel as in the first conventional example.
An object of the present invention is to provide an image display device that does not cause a problem of rewriting speed.

   The object is to input image data so that the display pixel array has two adjacent areas with different frame rates (> 0) in an image display device that displays the image data on an image display unit constituted by a display pixel array. This can be achieved by providing image data input means.

  According to the present invention, a high-quality image display device having about several hundred dots / inch, which is about the same as a printed matter, and having a number of display pixels of about several thousand × several thousand can be achieved without substantially increasing the rewriting speed of the display pixels. Can be realized.

[Example 1]
Embodiment 1 of the present invention will be described below with reference to FIG. 1, FIG. 2, FIG. 3, and FIG.
FIG. 4 is a diagram for explaining the use state of the present embodiment. The master unit 31 of the image display apparatus according to the present embodiment is placed in a house or the like and connected to a communication line. The image data generated in the parent device 31 is transferred to the child device 1 by microwave radio and displayed on the child device 1. The user uses the handset 1 in his / her hand and stores it in the charger 54 connected to the base unit 31 when not in use.

The configuration of this embodiment will be described below with reference to FIGS. 1 and 2. FIG. 1 is a block diagram of the present embodiment. The image data generation device 33 is connected to a data communication line for supplying compressed image information and a CD-ROM 34 which is a database. The image data generation device 33 further receives the generated image data as a microwave. A wireless interface 32 for transferring wirelessly is connected. These are provided in the master unit 31 of the image display device. The wireless interface 2 in the handset 1 exchanges wireless information with the wireless interface 32 in the base unit 31. There are four types of output from the wireless interface 2. The first output passes through the moving picture decoder 3 and the writing signal generation circuit 17 via the moving picture writing line 4, and the second output passes through the still picture decoder 5 and the still picture memory 6, and the still picture writing line. 7 to the write signal generation circuit 17, the third output passes through the text code memory 8, the outline font generation circuit 9, and the text write line 11 to the write signal generation circuit 17. The signal is input to the write signal generation circuit 17 via the icon / window write line 15 via the / window address memory 12 and the icon / window generation circuit 13. An outline font ROM 10 and an icon / window ROM 14 are connected to the outline font generation circuit 9 and the icon / window generation circuit 13, respectively. In addition to this, an icon / window position detection circuit 16 is connected to the icon / window address memory 12. In addition, a timing generation circuit 20 is provided, and the outputs of the position detection circuit 16 and the timing generation circuit 20 control the still image memory 6, the text code memory 8, and the icon / window address memory 12. The description of these outputs is omitted.

  The write signal generation circuit 17 is further connected to a display pixel array 18 that performs display using TN liquid crystal. The display pixel array 18 is provided with a touch sensor, and its output is input to the wireless interface 2 via the touch sensor output generation circuit 19.

FIG. 2 is an internal configuration diagram of the display pixel array 18. The display pixel region 53 is provided with display pixels in a matrix, and each pixel is composed of a TN liquid crystal capacitor 49, a TFT switch 48 connected thereto, and an AND gate circuit 47 that drives the gate of the TFT switch 48. ing. The AND gate circuit 47 and the TFT switch 48 are formed using a Poly-Si TFT CMOS process. The other end of the TFT switch 48 is connected to the signal line 45, and the input of the AND gate circuit 47 is connected to the vertical direction gate selection line 50 and the horizontal direction gate selection line 46 in the row and column directions, respectively. A moving image signal output circuit 43 and a still image signal output circuit 41 are connected to the signal line 45.
The vertical gate selection line 50 includes a moving image vertical direction selection circuit 52 and a still image vertical direction selection circuit 51, and the horizontal direction gate selection line 46 includes a moving image horizontal direction selection circuit 44 and a still image horizontal direction selection circuit 42. It is connected. The moving image signal output circuit 43, the still image signal output circuit 41, the moving image vertical direction selection circuit 52, the still image vertical direction selection circuit 51, the moving image horizontal direction selection circuit 44, and the still image horizontal direction selection circuit 42 are respectively written signals. The generation circuit 17 is connected.

  The operation of this embodiment will be described below with reference to FIGS. 1, 2 and 3. As shown in FIG. 1, compressed image information inputted from a data communication line and a CD-ROM 34, which is a database, is converted into moving image data, still image data, text data, and graphic information in an image data generating device 33. The data is decomposed into icons and window data, and input to the wireless interface 32 in a state where predetermined encoding is performed. This image data is input from the parent device wireless interface 32 to the child device wireless interface 2, and is input to a predetermined signal processing system for each type of data. That is, the moving image data is converted as it is into a video signal by the moving image decoder 3 and input to the write signal generation circuit 17 via the moving image write line 4. The still image is converted into a video signal by the still image decoder 5 and then once written in the still image memory 6. The still image data is sequentially input to the write signal generation circuit 17 via the still image write line 7 at a predetermined timing. Text data and graphic information are temporarily stored in the text code memory 8 in the state of a text code or the like. The text data and graphic information are sequentially read by the outline font generation circuit 9 at a predetermined timing, converted into still image data, and then input to the write signal generation circuit 17 via the text write line 11. The icon and window data are also temporarily stored in the icon / window address memory 12 in the state of data code and image address data. The icon and window data are sequentially read by the icon / window generation circuit 13 at a predetermined timing, converted into still image data, and then input to the write signal generation circuit 17 via the icon / window write line 15. The The reading of data from the still image memory 6, the text code memory 8, and the icon / window address memory 12 is controlled by a timing generation circuit 20 as will be described later. Further, the icon / window position and shape change are detected by the icon / window position detection circuit 16. When these changes are detected, the icon / window position detection circuit 16 interrupts the input of the still image data controlled by the timing generation circuit 20 to the signal generation circuit 17, and positions the icons and windows. Alternatively, still image data is written to the display pixel address of the portion whose shape has changed.

  The write signal generation circuit 17 sends a write signal to the display pixel array 18 based on the input image data, which will be described later with reference to FIG. The display pixel array 18 is provided with a touch sensor, and address information instructed by a fingertip or the like is input to the image data generation device 33 via the touch sensor output generation circuit 19 via the wireless interface 2 and the wireless interface 32. And tell the operator's command.

Next, the operation of the display pixel array 18 will be described with reference to FIG.
The write signal generation circuit 17 divides the image data into a moving image and a still image, and outputs data and an address, respectively. The moving image data is output to the moving image signal output circuit 43, the address is output to the moving image vertical direction selection circuit 52 and the moving image horizontal direction selection circuit 44, the still image data is output to the still image signal output circuit 41, and the address is the still image vertical. It is output to the direction selection circuit 51 and the still image horizontal direction selection circuit 42.

  When writing an image signal to a display pixel, the moving image vertical direction selection circuit 52 selects an address in the row direction, and the moving image horizontal direction selection circuit 44 selects an address that is a moving image in the selected row. . As a result, the AND gate circuit 47 of the selected display pixel is turned on, and the connected TFT switch 48 is turned on. At this time, the moving image signal output circuit 43 performs AD conversion of the moving image data to generate a signal voltage to be input to each selected display pixel and apply it to the signal line 45. This signal voltage is applied to the TFT switch. The signal is input to the TN liquid crystal capacitor 49 via 48. As for the still image, the signal writing method is the same as that of the moving image, and therefore the description is omitted here.

Next, the timing for writing moving images and still images to the display pixel array 18 will be described with reference to FIG. FIG. 3 is a diagram for explaining how to write a moving image and a still image to the display pixel array 18. In the display pixel area 53, display pixels are indicated by circles, and the display pixel array has 8 rows × 12 columns for simplicity. Among the display pixels, the ones labeled with a to d are moving image display pixels, and the others are still image display pixels. Here, it is assumed that the current leakage from the TN liquid crystal capacitor 49 is sufficiently small, and that the still image is flicker-free if the refresh write operation is performed m times per second, and the moving image is n per second. Assume that images are input. If the display pixels in the still image display area are j rows and the display pixels in the moving image display area are k rows, the ratio of the number of write rows per unit time between the still image and the moving image is (
m × j): (n × k). For example, if m is 10, n is 60, j is 8 and k is 4, this ratio is 1: 3. If writing is performed at a rate of 1 row of still image writing to 3 rows of moving image writing. I know it ’s good.

As another numerical example, a display pixel array 18 displaying a still image has 5000 rows of pixels, and a moving image displayed on 30 frames per second has 500 scanning lines. Assuming that Also in this case, if it is assumed that the current leak from the TN liquid crystal capacitor 49 is sufficiently suppressed, and the still image is not noticeable if flicker is not noticeable if the refresh write operation is performed once per second. The ratio of the number of written lines per unit time of a moving image can be 1: 3 from the above formula, and only a moving image having 500 scanning lines is simply displayed at 30 frames per second. In comparison, the writing speed to the display pixel array is only 33% higher ((1 + 3) /3=1.33). Since the display at the present time is about 480 lines and 60 frames per second according to the general VGA specification, the writing speed of 33% increase of 500 lines and 30 frames per second in this embodiment is compared with the current general display. However, there is an advantage that the writing speed can be reduced to about 70% (1.33 × (500/480) × (30/60) = 0.69).

  As described above, when the refresh writing frame rate of the still image is lowered, flicker occurs in the image. At this time, if writing to the display pixel is not sequentially scanned, but is divided into g fields and intermittently scanned for every g rows, flicker is suppressed and writing can be performed at a lower frame rate. it can.

In the above description of the present embodiment, the microwave radio is used from the parent device 31 to the child device 1. However, for example, other data transfer means such as infrared light communication or cable may be used. it is obvious.
In this embodiment, the unit of one display pixel is the same for both the moving image and the still image. However, in general, a moving image does not require the same high definition as a still image. The xi display pixel may be newly treated as a unit display pixel in the moving image. At this time, if signals are written to the h × i display pixels at the same timing, an unnecessary increase in writing speed can be prevented.

Generally, image signal accuracy of about 6 bits for moving images and about 8 bits for still images is required. Therefore, if the AD converter accuracy of the moving image signal output circuit 43 and the still image signal output circuit 41 is changed to 6 bits and 8 bits, respectively, the moving image signal output circuit 43 that requires higher speed operation has higher bit accuracy. It becomes low and design becomes easy for an AD converter.
In the present embodiment, the case where one moving image display area is surrounded by one still image display area has been described. However, according to the concept of the present invention, a moving image display area and a still image display area having different frame rates are used. If there is, the effect of the present invention can be obtained regardless of the number of regions or their arrangement. The effects of the present invention can also be obtained when still image display areas having different frame rates are adjacent to each other.
[Example 2]
A third embodiment of the present invention will be described below with reference to FIG. FIG. 6 is a configuration diagram of the write signal generation circuit 71 and the display pixel array 72 in this embodiment. The difference between the present embodiment and the first embodiment is that a two-gradation still image signal output circuit 63 is provided and the output of the two-gradation still image signal output circuit 63 is used when binary image data is written. .
When the two-gradation still image signal output circuit 63 is used, the AD converter is unnecessary, so that the power consumption is very small. For image data using only monochrome or 8 multi-colors, the power of the still image signal output circuit 41 can be temporarily stopped to reduce power consumption.

  According to the present invention, when image data is displayed on an image display unit configured by a display pixel array, an ultra-high-definition image display device can be realized without changing the display pixel rewriting speed.

FIG. 1 is a configuration diagram of the first embodiment. FIG. 2 is an internal configuration diagram of the display pixel array according to the first embodiment. FIG. 3 is a diagram for explaining how to write a moving image and a still image to the display pixel array according to the first embodiment. FIG. 4 is a diagram illustrating a use state of the first embodiment. FIG. 5 is a configuration diagram of a write signal generation circuit and a display pixel array in the second embodiment. FIG. 6 is a block diagram of the first conventional example. FIG. 7 is a block diagram of a second conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... cordless handset, 2 ... wireless interface, 3 ... moving image decoder, 4 ... moving image writing line, 5 ... still image decoder, 6 ... still image memory, 7 ... still image writing line, 8 ... text code memory, 9 ... Outline font generation circuit, 10 ... outline font ROM, 11 ... text writing line, 12 ... icon / window address memory, 13 ... icon / window generation circuit, 14 ... icon / window ROM, 15 ... icon / window writing line, 16 ... Position detection circuit, 17 ... write signal generation circuit, 18 ... display pixel array, 19 ... touch sensor output generation circuit, 20 ... timing generation circuit.

Claims (3)

An image display unit comprising a plurality of display pixels provided in a matrix;
A plurality of signal lines provided in the column direction for each display pixel;
An image data output circuit connected to each signal line for outputting image data to the signal line, and a writing pixel selection means for designating a pixel to which the image data is written,
An image display apparatus for displaying the composed the image display unit of the image data in the display pixel array,
As a selective output means of image data for the same display pixel via the signal line ,
A multi-value signal output circuit that is a first image data output circuit and a two gradation signal output circuit that is a second image data output circuit are provided as independent circuit configurations,
Further, the multi-value signal output circuit and the two gradation signal output circuit are connected to the same signal line, respectively.
The image display device characterized in that the multi-value signal output circuit and the two-tone signal output circuit alternatively or selectively output image data to the signal line . The image display device according to claim 1, wherein a moving image signal output circuit and a still image signal output circuit are provided as independent circuit configurations as multi-value image data output means for the display pixel array , still images have a partial region scanning means for making it possible to display only a portion of the display pixel array,
The partial area scanning means is constituted by a pixel selection circuit in column and row directions and AND logic provided in each pixel . 2. The image display device according to claim 1, wherein the multi-value image data output means for the display pixel array has a moving image signal output circuit and a still image signal output circuit as independent circuit configurations, and further stores dedicated for still image data. An image display device comprising means.

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