JPH11237864A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of displaying an arbitrary area in a display image displayed by an image signal in the display mode higher in resolution than that of the image signal transmitted from the main body side of a computer or the like can be displayed by using the liquid crystal display device low in resolution. SOLUTION: In this liquid crystal display device 110 provided with a liquid crystal display device 130 having a liquid crystal display panel 140 having the resolution of (m×n), an image mask means 120 is provided for outputting an image validate signal for validating the image signal in the arbitrary area of (m×n) pixels in the display image of (M×N on the conditions of M>m and N>n) displayed by the image signal in the display mode of resolution higher than the resolution of the liquid crystal panel to be inputted to the liquid crystal display device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and, more particularly, to a technique effective when applied to a display liquid crystal of a personal computer.

[0002]

2. Description of the Related Art Hitherto, a liquid crystal display device has been mainly used as a display unit of a notebook personal computer. However, in recent years, liquid crystal display devices have become smaller and smaller.
A liquid crystal display device is being used as a display device (or a liquid crystal monitor device) of a desktop personal computer, taking advantage of its light weight feature. In this liquid crystal display device, the installation place is 1/10 compared to a conventional CRT (cathode ray tube) display device.
And the power consumption is 1/3 to 1 /
It is possible to reduce the number to four. Such a technique is described in Japanese Patent Application No. 9-90402.

[0003]

In such a liquid crystal display device, an image in a display mode having a higher resolution than the resolution of the liquid crystal display device used in the liquid crystal display device (the resolution of the liquid crystal display panel) from the computer main body side. When the signal is transmitted, the liquid crystal display device cannot display the image signal in the high-resolution display mode. That is, assuming that the resolution of the liquid crystal display device used in the liquid crystal display device is 640 × 480 pixels, if the image signal transmitted from the computer main body is an image signal in the VGA display mode of 640 × 480 pixels, the resolution is 640 × 480 pixels. In a liquid crystal display device using a liquid crystal display device of × 480 pixels, the image signal can be displayed. However, the image signal transmitted from the computer main unit is displayed in a higher resolution display mode than the VGA display mode, for example, 800 × 600 pixel SVGA display mode, 1024 × 768 pixel XGA display mode, and 1280 × 1024 pixel SXGA display mode. In the mode, a liquid crystal display device using a liquid crystal display device having a resolution of 640 × 480 pixels has a problem that the image signal cannot be displayed.

In this case, there is no problem if a liquid crystal display device using a higher resolution liquid crystal display device is used as the liquid crystal display device. However, a liquid crystal display device using such a high resolution liquid crystal display device is used. Is expensive. Therefore, it is demanded that an image signal in a higher resolution display mode transmitted from the computer main body can be displayed on a liquid crystal display device using a lower resolution liquid crystal display device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to use a low-resolution liquid crystal display device in a liquid crystal display device from the side of a computer main body. It is an object of the present invention to provide a technique capable of displaying an arbitrary area in a display image displayed by an image signal of a higher resolution display mode transmitted.

[0006] The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0007]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

In a liquid crystal display device including a liquid crystal display device having a liquid crystal display panel having a resolution of (m × n), an image is displayed by a display mode image signal having a resolution higher than that of the input liquid crystal display panel. M ×
N, where M> m, N> n) (m) in the display image of pixels
.Times.n) image masking means for outputting an image valid signal for validating an image signal of an arbitrary region of pixels to the liquid crystal display device.

The image masking means counts the input horizontal synchronizing signal, and displays the image of (M × N) pixels displayed by an image signal in a display mode having a resolution higher than the resolution of the liquid crystal display panel. The first counting means for selecting any n rows of the above and a clock signal output to the liquid crystal display device are counted, and the display is performed by an image signal in a display mode higher in resolution than the resolution of the liquid crystal display panel (M × N) a second counting means for selecting an arbitrary m columns in a display image of pixels, and an input image signal of a display mode having a resolution higher than the resolution of the liquid crystal display panel is provided by the first counting means and the second counting means. And an effective signal generating means for outputting the image effective signal when the image signal is of an area selected by the counting means.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In all the drawings for describing the embodiments, those having the same functions are denoted by the same reference numerals, and their repeated description will be omitted.

FIG. 1 is a block diagram showing a schematic configuration of the liquid crystal display device according to the first embodiment of the present invention. In the figure, 100 is a computer main body, 110 is a liquid crystal display device, 120 is an image masking means, and 130 is T
A liquid crystal display device such as an FT liquid crystal display module, and 140 is a liquid crystal display panel. From the computer body 100 side
Vertical sync signal (Vsync), horizontal sync signal (Hsync)
c) and the analog image signal (R, G, B) are input to the image mask means 120 in the liquid crystal display device 110. From these signals, the image masking means 120
Indicates a vertical synchronization signal (V'sync), a horizontal synchronization signal (H'sync), and a display timing signal (DI
SP), a clock signal (CL) and a digital image signal (display data) (R ′, G ′, B ′) and send them to the liquid crystal display device 130.

FIG. 2 shows an image masking means 1 according to the embodiment.
FIG. 10 is a diagram for explaining the operation of No. 20; In the figure,
1A shows an output screen (output screen of 1024 × 768 pixels in the XGA display mode in FIG. 2) transmitted by the computer main body 100, and 1B shows an output screen (VGA display in FIG. 2) output to the liquid crystal display panel 140. Mode 6
(An output screen of 40 × 480 pixels). For example, as shown in FIG. 2A, the image masking unit 120 of the present embodiment is configured to display a display mode having a resolution higher than the resolution of the liquid crystal display panel 140 (in FIG.
When an image signal of 1024 × 768 pixels (XGA display mode) is transmitted, (m) in a display image of (M × N) pixels (1024 × 768 pixels in FIG. 2) displayed by the image signal is transmitted. × n) pixels (640 × 4 in FIG. 2)
A display timing signal (DISP; image effective signal of the present invention) for validating an image signal of an arbitrary area (80 pixels) is output to the liquid crystal display device 130. As a result, as shown in FIG. 2B, the liquid crystal display device 130 displays on the liquid crystal display panel 140 an arbitrary area in the output screen transmitted from the computer main body 100 side.

FIG. 3 shows an image masking means 1 according to this embodiment.
FIG. 4 is a circuit diagram showing an example of the circuit configuration of FIG. 20, and FIG. 4 is a timing chart for explaining the operation of the image mask means 120 shown in FIG. Polarity discriminating circuit 1 shown in FIG.
0 is Lo if the vertical synchronization signal (Vsync) input from the computer main body 100 is a positive pulse.
If the input vertical synchronizing signal (Vsync) is a negative pulse, the level is H level (hereinafter, L level).
It outputs an high level (hereinafter, H level). The vertical synchronization signal (Vsync) and the output of the polarity determination circuit 10 are:
Since the signal is input to the exclusive OR circuit 11, the exclusive OR circuit 11 outputs a vertical synchronization signal (V'sync) as shown in FIG. You. Similarly, a horizontal synchronization signal (H'sync) as shown in (b) of FIG. 4 is output from the polarity determination circuit 30 and sent to the liquid crystal display device 130.

When the vertical synchronizing signal (V'sync) becomes H level, the horizontal synchronizing signal (H'sync) is applied to the clock input terminal.
nc) is input to the Q of the D-type flip-flop circuit 12.
Since the output goes high, the AND circuit 15 goes high and the counter 16 is reset, as shown in FIG. As a result, the counter 16 starts counting the horizontal synchronization signal (H'sync), and when the count reaches (o), the output of the coincidence circuit 17 becomes H level as shown in (d) of FIG. Become. When the output of the matching circuit 17 becomes H level, as shown in FIG.
The Q output of the -K type flip-flop circuit 18 becomes H level, and the output of the OR circuit 20 becomes L level. Thereby, the reset of the counter 21 is released, and the counter 21 is reset.
Starts counting the horizontal synchronization signal (H'sync),
When the count reaches (m), the output of the coincidence circuit 22 goes high, as shown in FIG. When the output of the match circuit 22 goes high, the output of the OR circuit 20 goes high, the counter 21 is reset, and the Q output of the JK flip-flop circuit 18 goes low, and the output of the OR circuit 20 goes low. Is at the H level, so that the reset of the counter 21 is maintained.

The PLL circuit 50 outputs a horizontal synchronizing signal (H's
(sync), and generates a clock signal (CL) having a period of (1 / N1) of the horizontal synchronization signal (H'sync). The analog signal to which this clock signal (CL) is input
The digital converter (A / D) 52 converts the analog image signal (R, B, G) into a digital image signal (display data).
(R ′ · B ′ · G ′) and sends it to the liquid crystal display device 130.

When the horizontal synchronizing signal (H'sync) goes high, the Q output of the D-type flip-flop circuit 32 to which the clock signal (CL) is input to the clock input terminal is high.
Therefore, as described above, the AND circuit 35 goes high, and the counter 36 is reset. As a result, the counter 36 starts counting the clock signal (CL). When the count reaches (p), the output of the coincidence circuit 37 goes high, and the Q output of the JK flip-flop circuit 38 goes high. Level and the OR circuit 40
Becomes L level. As a result, the reset of the counter 41 is released, and the counter 41 outputs the clock signal (C
L) starts counting, and when this count reaches (n), the output of the coincidence circuit 42 goes high. When the output of the matching circuit 42 goes high, the output of the OR circuit 40 goes high, the counter 41 is reset, and
Since the Q output of the JK flip-flop circuit 38 goes low and the output of the OR circuit 40 goes high, the reset of the counter 41 is maintained.

Here, the count number of the counter 17 (o)
And the count number (p) of the counter 37 can be arbitrarily adjusted from the outside. JK flip-flop circuit 1
8 and the Q output of the JK flip-flop circuit 38.
The output is input to an AND circuit 53, and the output of the AND circuit 53 is a display timing signal (DIS).
P) is sent to the liquid crystal display device 130. In addition,
D-type flip-flop circuits (12, 13), inverters (14, 19), AND circuit 15, counters (16, 2)
1) The matching circuit (17, 22), the JK flip-flop circuit 18, and the OR circuit 20 constitute the first counting means of the present invention, and the D flip-flop circuits (32, 33) Inverter (34, 39), AND circuit 35, counter (36, 41), coincidence circuit (37, 4)
2), JK flip-flop circuit 38, and OR
The circuit 20 constitutes the second counting means of the present invention, and the AND circuit 53 constitutes the effective signal generating means of the present invention.

When the first display timing signal (DISP) is input after the input of the vertical synchronizing signal (V'sync), the liquid crystal display device 130 changes the signal to the first display timing signal (DISP).
If the display timing signal (DISP) is input as the display line, and the display timing signal (DISP) is input, the image is displayed on the liquid crystal display panel 140 as the display start position. As a result, even when an image signal in a display mode with a resolution higher than the resolution of the liquid crystal display panel 140 is transmitted from the computer main body 100 side, as shown in FIG. Can be displayed on the liquid crystal display panel 140.

FIG. 5 is a block diagram showing an application example of the liquid crystal display device of the present embodiment. In the application example shown in FIG. 5, two liquid crystal display devices (110A and 110B shown in FIG.
00, and each liquid crystal display device (11
0A or 110B), so that the two liquid crystal display devices (110A, 1B) have different display areas.
10B) to constitute a multi-screen. In FIG. 6, 1AA and 1AB denote display screens displayed on the respective liquid crystal display devices (110A and 110B) shown in FIG.
In the example shown in FIG. 6, the output screen (1B) transmitted from the computer main body 100 is displayed on two liquid crystal display devices (110A, 110A, 110B).
110B) shows a state where the image is divided into two and displayed.
As described above, it is possible to configure a multi-screen by using a plurality of liquid crystal display devices according to the present embodiment.

In the above-described embodiment, a case has been described where an analog interface for transferring image signals as analog signals is employed as an interface between the computer main body 100 and the liquid crystal display device 110. However, the present invention is not limited to this. Instead, a digital interface that transfers image signals as digital signals may be employed as an interface between the computer main body 100 and the liquid crystal display device 110.

As described above, the invention made by the present inventor is:
Although a specific description has been given based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the invention.

[0023]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows.

According to the present invention, a relatively inexpensive low-resolution liquid crystal display device is used, and an arbitrary one of the display images displayed by the image signal of the higher-resolution display mode transmitted from the computer body or the like. Area can be displayed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the image mask means of the present embodiment.

FIG. 3 is a circuit diagram illustrating an example of a circuit configuration of an image mask unit according to the present embodiment.

FIG. 4 is a timing chart for explaining the operation of the image mask means shown in FIG. 3;

FIG. 5 is a block diagram illustrating an application example of the liquid crystal display device of the present embodiment.

6 is a diagram showing an example of a display screen displayed on each of the liquid crystal display devices shown in FIG. 5 and an output screen transmitted from the computer main body side.

[Explanation of symbols]

10, 30 ... polarity discriminating circuit, 11, 31 ... exclusive OR circuit, 12, 13, 32, 33 ... D-type flip-flop circuit, 16, 21, 36, 41 ... counter, 14, 1
9, 34, 39 ... inverter, 15, 35, 53 ... AN
D circuit, 17, 22, 37, 42 ... matching circuit, 18, 3
8 JK flip-flop circuit, 50 PLL circuit, 51 frequency divider, 52 analog-digital converter,
100: Computer body, 110, 110A, 110
B: liquid crystal display device, 120: image mask means
130: liquid crystal display device; 140: liquid crystal display panel.

Claims (3)

[Claims] 1. A liquid crystal display device having a liquid crystal display device having a liquid crystal display panel having a resolution of (m × n), wherein the liquid crystal display device is displayed by an input image signal of a display mode having a higher resolution than the resolution of the liquid crystal display panel. (M × N, where M> m, N> n) in the display image of pixels (m × n)
A liquid crystal display device comprising: an image masking unit that outputs an image valid signal for validating an image signal of an arbitrary area of a pixel to the liquid crystal display device. 2. The image masking means counts an input horizontal synchronizing signal, and displays an (M × N) pixel image displayed by an image signal in a display mode having a resolution higher than the resolution of the liquid crystal display panel. A first counting means for selecting any n rows of the above, and a clock signal output to the liquid crystal display device is counted out, and displayed by an image signal of a display mode higher in resolution than the resolution of the liquid crystal display panel (M × N) a second counting means for selecting an arbitrary m columns in a display image of pixels; and an image signal of a display mode having a resolution higher than the resolution of the liquid crystal display panel to be inputted is provided by the first counting means and the second counting means.
2. The liquid crystal display device according to claim 1, further comprising: an effective signal generating unit that outputs the image effective signal when the image signal is an image signal of an area selected by the counting unit. 3. A display image of (M × N) pixels displayed by an image signal in a display mode having a resolution higher than the resolution of the liquid crystal display panel validated by the image masking means. 3. The liquid crystal display device according to claim 1, wherein an area of the pixel is adjustable from outside.