JPH11352463A - Picture display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a picture display from being biased to the beginning side for scanning a liquid crystal panel when a picture of a 4:3 aspect ratio is displayed on a picture display device with a liquid crystal panel of a wide screen of a 16:9 aspect ratio. SOLUTION: When converting a video signal into a digital data by an analog- to-digital translation circuit 23 and recording it in a line memory device 24, the number of the data for a blanking period is expanded by increasing a frequency of a writing clock signal to the line memory device 24 for the blanking period of the video signal by a record and reproduction control circuit 22. It is possible to change a video display period during one horizontal scanning period by reading this at a constant rate, so that a picture of a 4:3 aspect ratio can be displayed in the central part of a liquid crystal panel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image display device for displaying an image on a liquid crystal panel.

[0002]

2. Description of the Related Art In recent years, with the development of video equipment such as video tape recorders and video disk players and video software, there has been an increasing demand for large-screen image display devices for enjoying powerful images. As a conventional large-screen image display device, there has been a television using a CRT.
Since the CRT is used for the image display unit, there is a limitation in miniaturizing the apparatus due to physical restrictions of the CRT. An image display device using a liquid crystal panel for an image display unit has been proposed in order to eliminate this limitation and reduce the size of the device.

An example of a conventional image display apparatus using a liquid crystal panel is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-188104.

FIG. 4 is a block diagram showing an example of a conventional image display device using a liquid crystal panel.

In FIG. 4, an input video signal is processed by a video signal processing circuit 62 into a form for displaying an image on a liquid crystal panel 51 and applied to a horizontal scanning driver circuit 54. Further, the horizontal synchronizing signal and the vertical synchronizing signal are separated from the video signal by the synchronizing signal separating circuit 63, and are applied to the liquid crystal panel drive control circuit 64. The liquid crystal panel drive control circuit 64 generates a control signal for displaying an image on the liquid crystal panel 51 from the input synchronization signal, and
4 and the vertical scanning driver circuit 55.

[0006] In order to display an image on the liquid crystal panel 51, a horizontal scanning driver circuit 54 performs horizontal scanning, and a vertical scanning driver circuit 55 performs vertical scanning. Here, the scanning in the vertical direction is performed for all the lines on the liquid crystal panel 51 in order. The video signal lines 5 are displayed at the timing of displaying an image from each driver circuit.
6 is applied to the scanning signal line 57 and the transistor 5
An image is displayed on the liquid crystal panel 51 by controlling 3 and applying a signal to the display pixel 52.

Recently, video software having an aspect ratio of the screen of 16: 9 has been increasing in order to enjoy a realistic image, and an aspect ratio of an image display section has been increased to 16 to display such an image. : 9 wide-screen liquid crystal panels have also been made.

[0008]

As described above, in a wide-screen image display device in which the aspect ratio of the image display unit is 16: 9, an attempt is made to display a normal image in which the aspect ratio of the screen is 4: 3. In the case of an image display device using a liquid crystal panel, when scanning in the horizontal direction, it is necessary to sequentially scan all video signal lines and write video signals to display pixels. However, there is a problem that the image to be displayed is occupied by the left side of the screen, which is the horizontal scanning start side of the screen, and a part of the image is displayed on the right side of the screen.

[0009]

In order to solve the above-mentioned problems, an image display device of the present invention is an image display device for displaying an image on a liquid crystal panel, the liquid crystal panel for displaying a video signal. And recording means for recording the input video signal; reproducing means for reproducing the video signal recorded on the recording means; and control means for controlling the recording means and the reproducing means. The image to be displayed is displayed at an aspect ratio different from that of the liquid crystal panel.

According to the present invention, the aspect ratio is 16: 9.
In an image display device using a wide-screen liquid crystal panel, when displaying a normal image having an image aspect ratio of 4: 3, it is possible to control the horizontal display position of the image. Can be provided at the center of the screen.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image display device according to the present invention is an image display device for displaying an image on a liquid crystal panel, comprising a liquid crystal panel for displaying a video signal, and a digital data conversion device for converting an input analog video signal into digital data. Analog-to-digital conversion means for converting the video signal into digital data, recording means for recording the video signal converted into digital data, reproduction means for reproducing the video signal recorded in the recording means and converting the video signal into a video signal,
A digital conversion unit, a recording unit, and a control unit for controlling a reproduction unit, wherein the digital data is recorded at different speeds in the recording unit during a blanking period and a video display period of the input analog video signal. An image to be displayed on the liquid crystal panel is displayed at a different aspect ratio from that of the liquid crystal panel by reproducing the data at a constant speed after recording the data, and the aspect ratio is 16: 9. In an image display device using a liquid crystal panel having a screen, an image having an aspect ratio of 4: 3 can be displayed at the center of the screen of the liquid crystal panel.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a configuration diagram showing a configuration of an image display device according to an embodiment of the first invention, wherein 1 is a wide-screen liquid crystal panel having a screen aspect ratio of 16: 9,
Reference numeral 2 denotes a display pixel unit for displaying an image on the liquid crystal panel 1, 3 denotes a transistor for controlling image display on the display pixel unit 2, and 4 denotes horizontal scanning for displaying an image on the liquid crystal panel 1. A horizontal scanning driver circuit 5 for performing vertical scanning similarly to perform vertical scanning;
Reference numeral 6 denotes a video signal line for transmitting a video signal from the horizontal scanning driver circuit 4, reference numeral 7 denotes a scanning signal line for transmitting a scanning signal from the vertical scanning driver circuit 5, and 11
Is an image display control circuit that switches the aspect ratio and display position of an image according to an input video signal, 12 is a video signal processing circuit that processes a video signal into a form for displaying an image on the liquid crystal panel 1, and 13 is a video signal processing circuit. A synchronizing separation circuit 14 for separating the horizontal synchronizing signal and the vertical synchronizing signal, and a liquid crystal panel drive control circuit 14 for generating a control signal for displaying an image on the liquid crystal panel 1. In a general liquid crystal panel, the number of pixels in the display pixel portion is, for example, (horizontal) 852 pixels × (vertical) 480.
Although there are many display pixels such as pixels, they are omitted in FIG. 1 for simplicity.

FIG. 2 is a block diagram showing the configuration of the image display control circuit 11. The image display control circuit 21 is a digital-analog conversion means, which is an analog-digital conversion circuit 23 for converting an input analog video signal into digital data, and a recording means, which is for recording a digital data video signal. A digital-to-analog conversion circuit 25 that reproduces a video signal recorded in the line memory circuit 24 and converts the video signal into an analog video signal; a reference clock generation circuit 21; a recording / reproduction control circuit 22 It consists of.

The reference clock generation circuit 21 generates a reference clock signal which is a reference for the operation of the image display control circuit 11 based on the vertical synchronization signal and the horizontal synchronization signal generated by the synchronization signal separation circuit 13. The reference clock signal is PLL
It can be easily generated by using a circuit or the like.

The recording / reproducing control circuit 22 receives a reference clock signal from the reference clock generating circuit 21 and supplies a data conversion clock signal for controlling the operation of the analog-digital conversion circuit 23 and the digital-analog conversion circuit 25 to the line memory circuit 24. A write clock signal for writing a data signal and a read clock signal for reading a data signal are generated. The generation of each clock signal is
It is controlled by timing data (the generation circuit is not shown) set in the recording / reproduction control circuit 22 according to the type of the input video signal.

FIG. 3 is a conceptual diagram showing a method of controlling image display by the image display control circuit 11.

The operation of the image display control circuit 11 of the image display device according to one embodiment of the present invention will be described below with reference to FIGS.

The clock frequency of the data conversion clock signal for the analog-to-digital conversion circuit 23 is set in accordance with the input video signal and converts the video signal into digital data at a constant timing. In general, a frequency corresponding to the total number of dots of the video signal is selected as the clock frequency. Next, the write clock signal for the line memory circuit 24 is set to a higher frequency than the data conversion clock signal of the analog-digital conversion circuit 23 during the blanking period of the video signal, and digital data is recorded in the line memory circuit 24. . On the other hand, in the video period of the video signal, the write clock signal is set to the same frequency as the data conversion clock signal of the analog-digital conversion circuit 23. As described above, by increasing the frequency of the write clock signal during the blanking period, many data signals during the blanking period are recorded in the line memory circuit 24. The clock frequency of the data conversion clock signal for the digital-analog conversion circuit 25 is such that all display pixels (852 pixels in this embodiment) in the horizontal direction of the liquid crystal panel 1 are scanned during one horizontal scanning period of the input video signal. Set to a frequency that can be used. Image control circuit 1
By operating the LCD device 1 in this manner, an image having an aspect ratio of 4: 3 is displayed at the center of the LCD panel in an image display device using a wide-screen liquid crystal panel having an aspect ratio of 16: 9. Can be.

For the sake of understanding, description will be made again with specific numbers. The number of pixels in the horizontal direction of the display pixel portion of the liquid crystal panel 1 is eight.
The input video signal has a total of 800 dots in one horizontal scanning period and 64 dots in the video period.
Consider the case of a VGA standard video signal with 0 dots and an aspect ratio of 4: 3. In this case, the number of dots in the blanking period is 800 dots−640 dots = 160 dots.
The number of data in the blanking period can be expanded to 240 by setting the clock signal for writing to No. 4 to 1.5 times the frequency of the clock signal in the video period. Thereby, the number of dots in one horizontal scanning period can be expanded to 880 dots, which is equal to or larger than the number of display pixels in the horizontal direction of the liquid crystal panel 1. Since this expanded image has sufficient data during the blanking period, the V has an aspect ratio of 4: 3.
The video signal of the GA standard can be displayed at the center of the wide-screen liquid crystal panel 1.

As described above, by using the line memory device so as to increase the frequency of the write clock signal to the line memory device during the blanking period of the video signal, a circuit having a simple structure can be used in the horizontal direction. The number of pixels can be increased, an image having an aspect ratio of 4: 3 can be displayed at the center of a wide-screen liquid crystal panel, and a great effect that an effective video display can be performed can be obtained. .

In the image display apparatus according to one embodiment of the present invention, the video signal once converted into digital data by the image display control circuit 11 is again converted into an analog signal. Do the processing,
Obviously, it may be configured to input to the liquid crystal panel.

[0022]

As described above, according to the image display device of the present invention, the liquid crystal panel for displaying the video signal, the recording means for recording the input video signal, and the recording means for recording the video signal. A reproducing unit for reproducing a video signal; and a control unit for controlling the recording unit and the reproducing unit, and a speed of recording data on the recording unit during a blanking period and a video display period of the input video signal. By operating so that the data is recorded and then reproduced at a constant speed after recording the data, the image displayed on the liquid crystal panel is displayed at a different aspect ratio from the liquid crystal panel. 4: 3 aspect ratio in center
The image display device which can display the image of the present invention can be provided, and there is a great effect that an effective image display can be performed in the image display device having a wide screen.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of an image display device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an image display control circuit of the apparatus.

FIG. 3 is a timing chart showing the operation of the image display control circuit of the device.

FIG. 4 is a configuration diagram showing a configuration of an example of a conventional image display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 Display pixel part 4 Horizontal scanning driver circuit 5 Vertical scanning driver circuit 11 Image display control circuit 12 Video signal processing circuit 13 Synchronization separation circuit 14 Liquid crystal panel drive control circuit

Claims (2)

[Claims] 1. An image display device for displaying an image on a liquid crystal panel, comprising: a liquid crystal panel for displaying a video signal; recording means for recording an input video signal; and recording means for recording the input video signal. An image display, comprising: reproduction means for reproducing a video signal; and control means for controlling the recording means and the reproduction means, wherein an image displayed on the liquid crystal panel is displayed at an aspect ratio different from that of the liquid crystal panel. apparatus. 2. An image display device for displaying an image on a liquid crystal panel, comprising: a liquid crystal panel for displaying a video signal; analog-digital conversion means for converting an input analog video signal into digital data; Recording means for recording a video signal converted into digital data; reproducing means for reproducing digital video signal data recorded in the recording means to convert the data into a video signal; analog-digital conversion means; recording means; The digital data is recorded at different speeds during the blanking period and the video display period of the input analog video signal, and the digital data is reproduced at a constant speed. The image displayed on the liquid crystal panel is displayed at a different aspect ratio from that of the liquid crystal panel. Image display device.