JPH06189237A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide a liquid crystal display device which is capable of performing a bright and high picture quality magnifying screen display without using a magnifying device of a great constitution. CONSTITUTION:This device is provided with horizontal driving circuits 8r, 8g, 8b and vertical driving circuits 9r, 9g, 9b which are composed of shift registers for scanning the liquid crystal panels 10r, 10g, 10b of each liquid crystal projectors A, B, C, D in horizontal and vertical directions, and displays a large screen by changing the frequency and phase of a clock pulse for controlling each shift register and by arranging the projected screen from each liquid crystal projector A, B, C, D in longitudinal and lateral directions.

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 in which projection screens from a plurality of liquid crystal projectors are combined vertically and horizontally to form one screen.

[0002]

2. Description of the Related Art Conventionally, when a plurality of liquid crystal projectors are combined to display a large screen, conventionally, an analog video signal is converted into a digital video signal by an A / D converter and the digital video signal is written in a predetermined manner. Enlargement device configured to store in a field memory in accordance with a clock, thereafter read the stored digital video signal in accordance with a predetermined read clock, and convert the read digital video signal into an analog video signal by a D / A converter. It is well known to connect a computer to a liquid crystal projector to display a magnified image on the screen.

Further, unlike the above-mentioned example, a magnifying device composed of an A / D converter, a double speed converter, a frame memory and a D / A converter is connected to a liquid crystal projector to display a magnified image. Methods are also known.

[0004]

The conventional enlargement display method as described above requires the enlargement device having the bulky configuration as described above, and therefore the system scale becomes large.
Further, there is a problem that it also leads to high cost, and there is a demand for the development of a liquid crystal display device capable of displaying a large screen without the need for a conventional enlargement device.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a liquid crystal display device capable of performing bright, delicate and large-screen display without using a conventional magnifying device. To do.

[0006]

A liquid crystal display device according to the present invention is a liquid crystal display device in which the screens of a plurality of liquid crystal projectors each having a liquid crystal panel are vertically and horizontally combined to form one screen. A horizontal drive circuit having a shift register for scanning the liquid crystal panel in the horizontal direction, a vertical drive circuit having a shift register for scanning the liquid crystal panel of each of the liquid crystal projectors in the vertical direction, and the horizontal drive circuit and the shift register of the vertical drive circuit. And a timing controller for changing the frequency and phase of the clock pulse for controlling the clock pulse.

[0007]

In the liquid crystal display device of the present invention, depending on the combination of a plurality of liquid crystal projectors, the frequency of the clock pulse for controlling the respective shift registers for scanning the liquid crystal panel of each liquid crystal projector in the horizontal and vertical directions, and An enlarged screen is displayed by changing the phase, and the screens projected from each liquid crystal projector are combined vertically and horizontally to form one screen.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments.

FIG. 1 is a schematic view showing an embodiment of the present invention, in which A, B, C and D are liquid crystal projectors, and the liquid crystal projectors A, B, C and D are connected to a screen 1. The image is projected. Each liquid crystal projector A, B,
The projection screens 1a, 1b, 1c, 1d from C and D are combined to form one screen.

FIG. 2 shows liquid crystal projectors A, B, C and D.
3 is a block diagram showing the internal configuration of the liquid crystal projectors A, B, C, and D, and video signals are input to the video signal input terminals 2a, 2b, 2c, and 2d. The internal configurations of the liquid crystal projectors A, B, C, D are the same, and FIG. 2 shows only the internal configuration of the liquid crystal projector A, and the internal configurations of the other liquid crystal projectors B, C, D are shown. Illustration is omitted.

In FIG. 2, reference numeral 5 is a video processing circuit for separating the video signal input through the video signal input terminal 2a into three primary color signals of R, G and B. The R signal, G signal, and B signal are output to the corresponding horizontal drive circuits 8r, 8g, and 8b, which will be described later. Further, a video signal from the outside is also input to the sync separation circuit 6 via the video signal input terminal 2a, and the sync separation circuit 6 separates the sync signal from the input video signal and changes it in the timing controller 7. Output to the delay circuit 7a. The variable delay circuit 7a delays the synchronization signal according to the control signal from the delay control signal input terminal 3a as necessary, and outputs the delayed synchronization signal to the phase comparator 7b. The phase comparator 7b compares the phase of this input synchronization signal with the control signal from the output gate circuit 7g, and outputs a signal indicating the phase difference to the voltage controlled oscillator 7c. The oscillation frequency of the voltage controlled oscillator 7c is controlled by this input signal, and the oscillation output is input to the changeover switch 7d.

The output terminal of the changeover switch 7d is changed over in accordance with the changeover signal from the changeover control signal input terminal 4a. Specifically, in the case of normal display, the changeover switch 7d is changed over to the a side, and a combination display of a plurality of liquid crystal projectors is displayed. In the case of, it can be switched to the b side.
A first counter 7e and a second counter 7f are connected to the a-side terminal and the b-side terminal of the changeover switch 7d, respectively. Each counter 7e, 7f counts the oscillation output of the voltage controlled oscillator 7c, and the counted result is obtained. Output to the output gate circuit 7g. Second
The count output of the counter 7f is twice the count output of the first counter 7e. Variable delay circuit as described above
The timing controller 7 is composed of 7a, a phase comparator 7b, a voltage controlled oscillator 7c, a changeover switch 7d, first and second counters 7e and 7f, and an output gate circuit 7g.

Further, 10r, 10g and 10b are, for example, 240 vertical lines,
It is a transmissive liquid crystal panel for R, G, and B consisting of 480 dots in width, and each liquid crystal panel 10r, 10g, 10b is a corresponding horizontal drive circuit (column driver) 8r, 8g, 8b and a vertical drive circuit ( Row driver) 9r, 9g, 9b and connected. These horizontal drive circuits 8r, 8g, 8b and vertical drive circuits 9r, 9g, 9b
Are all composed of shift registers.

The output gate circuit 7g receives the horizontal start pulse SH of the horizontal drive circuits 8r, 8g, 8b and the horizontal shift pulse of its shift register based on the counting results of the counters 7e, 7f.
CH and form them and output them to each horizontal drive circuit 8r, 8g, 8b. Further, the output gate circuit 7g forms the vertical start pulse SV of the vertical drive circuits 9r, 9g, 9b and the vertical shift pulse CV of the shift register thereof on the basis of the counting results of the counters 7e, 7f, and makes them vertical Output to drive circuits 9r, 9g, 9b. Each horizontal drive circuit 8r, 8g, 8b, based on these horizontal start pulse SH and horizontal shift pulse CH,
The R, G, and B primary color signals are output to the corresponding liquid crystal panels 10r, 10g, and 10b for each horizontal period. Meanwhile, each vertical drive circuit
9r, 9g, 9b sequentially select each line of each liquid crystal panel 10r, 10g, 10b based on the vertical start pulse SV and the vertical shift pulse CV in synchronization with a horizontal signal.

Hereinafter, the operation of the liquid crystal display device of the present invention will be described separately for normal display and combination display.

In the case of normal display, no control signal is input from the delay control signal input terminal 3a, and the changeover switch is changed by the changeover signal from the changeover control signal input terminal 4a.
7d is connected to the output terminal a side. Video signal input terminal
When a video signal is input to the video processing circuit 5 via 2a,
Luminance / color separation processing, matrix processing, etc. are performed on this video signal to separate it into three primary color signals of R, G, B, and each R, G, B signal is used as a display signal in a horizontal drive circuit
Output to 8r, 8g, 8b.

The video signal is also input to the sync separation circuit 6 to separate the sync signal, and the separated sync signal is
It is supplied to the phase comparator 7b via the variable delay circuit 7a. In the phase comparator 7b, the phase of this synchronizing signal and the output gate circuit
The phase of the control signal from 7g is compared, and a signal corresponding to the obtained phase difference is given to the voltage controlled oscillator 7c. The oscillation frequency of the voltage controlled oscillator 7c is controlled by this signal, the oscillation output of the voltage controlled oscillator 7c synchronized with the synchronizing signal is counted by the first counter 7e, and the counting result is output to the output gate circuit 7g.

Based on the counting result, as shown in FIG. 3, in the output gate circuit 7g, the horizontal driving circuits 8r, 8g,
8b horizontal start pulse SH1 and horizontal shift pulse CH1
And the vertical start pulse SV1 and the vertical shift pulse CV1 of the vertical drive circuits 9r, 9g, 9b are formed. Each of these pulses is output to the horizontal drive circuits 8r, 8g, 8b and the vertical drive circuits 9r, 9g, 9b. The vertical shift pulse CV1 is fed back to the phase comparator 7b, and the pulses SH1, CH1, SV1, and
CV1 is synchronized with the sync signal by PLL control.

In each horizontal drive circuit 8r, 8g, 8b, the primary color signals of R, G, B are sampled 480 times in one horizontal period based on the horizontal start pulse SH1 and the horizontal shift pulse CH1, and one horizontal period is sampled. The image signals of the three primary colors are applied to the liquid crystal panels 10r, 10g, and 10b. Then, each vertical drive circuit 9r, 9g, 9b, in accordance with the vertical start pulse SV1 and the vertical shift pulse CV1, is synchronized with the horizontal synchronizing signal to each liquid crystal panel 10r, 10g, 10b.
Each line of G1, G2, G3, ..., G240 is sequentially selected. In this way, by controlling the drive of the horizontal drive circuits 8r, 8g, 8b and the vertical drive circuits 9r, 9g, 9b, each liquid crystal panel 10r, 10g
g, 10b is scanned and the image is displayed on the screen 1.

Next, as shown in FIG. 4, the screen of one liquid crystal projector is doubled vertically and horizontally, and the projection screens of the four liquid crystal projectors A, B, C and D are combined to form one screen. The operation of configuring will be described.

In this case, the changeover switch 7d is changed over to the output terminal b side, and the oscillation output of the voltage controlled oscillator 7c is counted by the second counter 7f. Where the second
Since the count output of the counter 7f is twice the count output of the first counter 7e, the display screen of one liquid crystal projector becomes twice as large as the normal display by selecting the second counter 7f. .

The horizontal sync signal separated by the sync separation circuit 6 is input to the delay control signal input terminal 3a in the variable delay circuit 7a.
It is delayed by an arbitrary time based on the control signal from, and the horizontal start pulse position is moved according to the delay time to determine the display period in the liquid crystal panels 10r, 10g, 10b. Similarly, the separated vertical synchronizing signal is similarly delayed in the variable delay circuit 7a by an arbitrary time to determine the display period in the vertical direction. Therefore, by appropriately setting the control signal to the variable delay circuit 7a, the liquid crystal panels 10r, 10
The display period in g, 10b can be arbitrarily determined.

As shown in FIG. 4, when a combination of vertical two surfaces and horizontal two surfaces is used to form a four-surface configuration, a delay control signal input terminal is provided.
An appropriate control signal is input to the variable delay circuit 7a of each liquid crystal projector A, B, C, D via 3a, and the synchronization signal in each liquid crystal projector A, B, C, D is set to the position as shown in FIG. If the relation is set, one screen can be configured with four surfaces. In FIG. 5, (a), (b), (c), and (d) are RGB colors in the liquid crystal projectors A, B, C, and D, respectively.
It shows the horizontal sync signal HS, vertical sync signal VS, horizontal start pulse SH, and vertical start pulse SV associated with the signal.

According to the horizontal synchronizing signal HSa and the vertical synchronizing signal VSa given to the phase comparator 7b of the liquid crystal projector A,
Its horizontal start pulse SHa and vertical start pulse SV
Since a is at the position shown in Fig. 5 (a), the upper left quarter screen is displayed enlarged (see Fig. 4). In the other liquid crystal projectors B, C, and D, the synchronization signal is delayed, and the horizontal start pulse SH and vertical start pulse SV are shifted, and the upper right 1/4 screen, lower left 1/4 screen, lower right 1 screen, respectively. / 4 Enlarge the screen (see Fig. 4).

[0025]

As described above, in the liquid crystal display device of the present invention, the magnifying device as in the conventional example is not specially used.
Since the timing controller is configured to generate the clock pulse for controlling the shift registers of the horizontal drive circuit and the vertical drive circuit by changing the frequency and phase thereof, it is possible to easily display an enlarged screen and to display a plurality of liquid crystal projectors. A bright, high-quality large-screen display can be performed by combining projection screens.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a liquid crystal projector.

FIG. 3 is a timing chart of the liquid crystal projector for normal display.

FIG. 4 is a diagram showing a display example in the case where the screen is composed of four display screens.

FIG. 5 is a timing chart of the liquid crystal projector in the case of enlarged display.

[Explanation of symbols]

 1 Screen 2a, 2b, 2c, 2d Video signal input terminal 3a Delay control signal input terminal 4a Switching control signal input terminal 5 Video processing circuit 6 Sync separation circuit 7 Timing controller 7a Variable delay circuit 7b Phase comparator 7c Voltage controlled oscillator 7d Changeover switch 7e First counter 7f Second counter 7g Output gate circuit 8r, 8g, 8b Horizontal drive circuit 9r, 9g, 9b Vertical drive circuit 10r, 10g, 10b Liquid crystal panel A, B, C, D Liquid crystal projector

Claims (1)

[Claims] 1. A liquid crystal display device in which the screens of a plurality of liquid crystal projectors each having a liquid crystal panel are combined vertically and horizontally to form one screen, and a horizontal display having a shift register for scanning the liquid crystal panels of each liquid crystal projector in the horizontal direction. A drive circuit, a vertical drive circuit having a shift register for vertically scanning the liquid crystal panel of each of the liquid crystal projectors, and a clock pulse for controlling the horizontal drive circuit and the shift register of the vertical drive circuit. And a timing controller for changing and generating the liquid crystal.