KR0138339B1 - Liquid crystal projection system - Google Patents

Abstract

A liquid crystal projection value for expanding and projecting on a predetermined screen is disclosed. The device includes a luminance / color signal separation circuit for receiving a composite video signal and separating it into a luminance signal and a color signal, a synchronous signal separation circuit for separating vertical and horizontal synchronous signals, and a demodulation / correction circuit for demodulating the color signal and correcting the luminance signal. A sequential scan conversion circuit for sequential scan conversion, a matrix for generating a primary color signal, a signal selection circuit for signal selection and output, a liquid crystal interface for interfacing the selected primary color signal, a liquid crystal controller for outputting a timing control signal; In response to the timing control signal, R, G, and B signals are inputted to display the R, G, and B signals of the interfaced primary colors, respectively, and displayed on the screen. Regardless of the mode, the image signal of the computer can be projected in high resolution.

Description

LCD Projection Device

1 is a block diagram for explaining a conventional liquid crystal projection value.

2 is a diagram for explaining an example of displaying a conventional computer image signal on a liquid crystal projection apparatus.

3 is a block diagram for explaining a liquid crystal projection value according to the present invention.

4 is a diagram for explaining the liquid crystal projection shown in FIG. 3 in more detail.

5 is a waveform diagram for explaining a signal applied to the liquid crystal projection apparatus shown in FIG.

6 is a diagram for explaining an image displayed by the liquid crystal projection apparatus according to the present invention.

The present invention relates to a liquid crystal projection apparatus, and more particularly, to a liquid crystal projection apparatus capable of receiving a signal from a computer graphics card and projecting the same.

In general, a liquid crystal projector (LCD Projector) using a liquid crystal projection value refers to a device for expanding and projecting the image displayed on the liquid crystal display on a predetermined screen. In this case, the panel of the liquid crystal display device is a pixel number of 640 (horizontal) × 480 (vertical) pixels, and in particular, a thin film transistor (TFT) is used to express a color image.

1 is a block diagram for explaining a conventional liquid crystal projection value. The conventional liquid crystal projection of FIG. 1 has a Y / C separation unit 10, a color demodulation and matrix unit 20, a synchronization signal separation unit 30, a liquid crystal interface unit 40, a liquid crystal controller 50, and a liquid crystal display. The apparatus 60 is comprised. First, the composite video signal is input through the terminal 5 and separated into the luminance signal (Y) and the color signal (C) through the Y / C separation unit 10, and the red, green, and blue colors are applied through the color demodulation and matrix unit 20. The color signals R, G, and B are restored and the converted signals are converted through the liquid crystal interface 40 to be suitable for the liquid crystal display 60. Subsequently, in response to the timing control signal of the liquid crystal controller 50, the liquid crystal display 60 displays an image and projects the image. In this case, the liquid crystal controller 50 receives the vertical and horizontal synchronous signals through the synchronous signal separator 30 that receives the luminance signal Y separated through the Y / C separator 10 and separates the synchronous signals. The timing control signal of the liquid crystal display 60 is generated.

Therefore, when receiving a computer image signal instead of the composite image signal, as shown in FIG. 2, a signal conversion encoder 80 for separately interfacing between the computer 70 and the liquid crystal projection apparatus or the television 90 is provided. It must be provided separately and converted into a television signal. That is, there is a problem in that the image signal of the computer cannot be directly used. Further, as described above, not only the signal is degraded in the process of converting it to a television signal, but also the signal is also degraded to restore the primary color signals R, G, and B. Therefore, there is a problem that the resolution is lowered due to such deterioration.

Accordingly, it is an object of the present invention to provide a liquid crystal projection that can receive a computer image signal as well as a composite image signal and can project in a high resolution in a high resolution.

In order to achieve the above object of the present invention, the liquid crystal projection device according to the present invention in the liquid crystal projection apparatus for magnifying and projecting on a predetermined screen,

Luminance / color signal separation means for receiving a composite video signal and separating it into a luminance signal and a color signal, synchronous signal separation means for separating the vertical and horizontal synchronization signals upon receiving the luminance signal, and receiving the demodulation signal and the color signal and demodulating them. And demodulation / correction means for correcting the luminance signal, sequential scan conversion means for receiving the vertical and horizontal synchronization signals and the demodulated and corrected signals, and sequentially scanning and converting the sequential scan converted signals. Matrix means for generating a signal, signal selection means for receiving vertical and horizontal synchronous signals from the primary color signal and the sequential scan conversion means, primary color signals and vertical and horizontal synchronous signals from the outside, and selecting and outputting the same; Liquid crystal interface means for interfacing the selected primary color signal in response to a horizontal synchronization signal; Liquid crystal control means for receiving the selected vertical and horizontal synchronization signals from a signal selection means and outputting a timing control signal, and receiving the R, G, and B signals of the interfaced primary color signals in response to the timing control signal, respectively, on the screen; Characterized in that the projection is provided with a liquid crystal display device for displaying the R, G and B signals.

Hereinafter, a driving circuit of the liquid crystal projection apparatus according to the present invention will be described with reference to the accompanying drawings.

3, the Y / C separation unit 110, the synchronization signal separation unit 12, the color demodulation and luminance signal correction unit 130, the sequential scan conversion unit 140, and the matrix unit 150, the signal selector 160, the computer 170, the liquid crystal interface unit 180, the liquid crystal controller 190, the liquid crystal display device 200 for the R signal, the liquid crystal display device 210 for the G signal, the liquid crystal display for the B signal The device 220 is configured.

First, the composite video signal is input to the Y / C separation unit 110 through an input terminal 95 and separated into a color signal C and a luminance signal Y. Subsequently, the vertical and horizontal synchronization signals are separated from the separated luminance signal Y through the synchronization signal separation unit 120. In addition, the color demodulation and luminance signal correction unit 130 receives the separated color signal C and the luminance signal Y, demodulates the R-Y and G-Y signals, corrects the luminance signal Y, and outputs them. Subsequently, the sequential scan converter 140 receives the vertical and horizontal synchronous signals H and V and the Y, RY, and BY signals from the color demodulation and luminance signal compensators 130, respectively, from the sync signal separator 120. FIG. . At this time, the Y, R-Y, B-Y signal has a horizontal frequency of 15.75 Hz by interlaced scanning method. Therefore, in order to convert this to the sequential scanning method, the horizontal frequency conversion unit 140 converts the horizontal frequency to have a 31.5 kHz component. In other words, after analog / digital conversion, the output signal is doubled compared to the clock input into the memory using line memory or field memory, and the input signal is compressed 1/2 in time axis. To configure. 525 scan lines are formed by setting 1H (1 horizontal scanning period) to 1 / 31.5 ms. In addition, the frequency of the horizontal synchronization signal is also converted from 15.75 kHz to 31.5 kHz. Subsequently, the matrix number unit 150 receives the output signal of the sequential scan converter 140, that is, receives the signals 1/2, 2 (RY), and 2 (BY), which are compressed for 1/2 hour, according to Equation 1 below. Make a signal.

G-Y = -0.51 (R-Y)-0.19 (B-Y) ....... Equation 1

The G-Y, R-Y, B-Y and the luminance signal Y are added to generate the primary color signals R, G, and B. Subsequently, the signal selector 160 receives the vertical and horizontal synchronous signals H1 and V1 from the sequential scan converter 140 and the primary color signals R1, G1 and B1 from the matrix unit 150 or is perpendicular from the computer 170. And horizontal output signals H2 and V2 and primary color signals R2, G2 and B2. That is, the composite video signal input through the input terminal 95 or the image signal of the computer 170 is selectively output. Subsequently, the liquid crystal interface unit 180 receives the vertical and horizontal synchronous signals H3 and V3 and the primary color signals R3, G3, and B3 selected by the signal selector 160 to provide characteristics of the liquid crystal panel of the liquid crystal display. The signal is inverted in gamma correction and line units to output primary color signals R4, G4, and B4. Subsequently, the R signal liquid crystal display device 200, the G signal liquid crystal display device 210, and the B signal liquid crystal display device 220 respond to the timing control signal of the liquid crystal controller 190. (R4, G4, B4) are input respectively to display an image.

4 is a detailed block diagram of any one of the R signal liquid crystal display device 200, the G signal liquid crystal display device 210, and the B signal liquid crystal display device 220 shown in FIG. And source drivers 240 and 250 and gate drivers 260 and 270. The liquid crystal panel 230 includes 640 × 480 pixels, and each pixel is connected to one output line of the source driver 240 and 250 and one output line of the gate driver 260 and 270, respectively. One of the output lines of the drivers 260 and 270 is output at a high level, and an image signal is supplied to any of the output lines of the source drivers 240 and 250 so that an image is represented by each pixel, in particular a TFT. The gate drivers 260 and 270 start when the STV (Vertical Start Clock) clock of FIG. 5B is applied, and the gate drivers 260 and 270 are driven by each clock of the CPV (Vertical Clock for Shift Register) of FIG. 5C. The first to the 480th shifts in order. In addition, the source drivers 240 and 250 receive the horizontal start clock (STH) and the horizontal clock for shift register (CPH) clocks to perform the same operations as the gate drivers 260 and 270 described above. FIG. 5A illustrates the composite image signal. At this time, in the case of a graphics card, particularly a VGA card of the computer 170, the frequency of the vertical synchronization signal V2 becomes 60 Hz or 70 Hz according to the graphics mode. Accordingly, since the vertical line of the liquid crystal panel 230 is 480, when the frequency of the vertical synchronization signal V2 is 60 Hz, the vertical lines are 480, and the output is properly output. However, when the frequency is 70 Hz, the vertical lines are 400. The output is not normal. That is, when the screen of FIG. 6a is the original screen, the screen is not normally displayed as shown in FIG. 6c. Accordingly, the gate drivers 260 and 270 connected to the vertical lines of the 401 th to 480 th because the vertical lines are properly output from the first to the 400 th and the vertical lines of the 401 th to 480 th are not normally output. By applying the fifth clock and a reset clock to the shift register of < RTI ID = 0.0 >, < / RTI > the remaining pulses are eliminated so that the screen is not displayed. As shown in FIG.

As described above, the liquid crystal projection device according to the present invention can enlarge and project the image signal of a computer without a separate signal conversion device. In particular, there is an effect that the high-resolution magnification projection is possible while preventing the degradation of the resolution due to signal degradation in the signal conversion process.

Claims (3)

In the liquid crystal projection apparatus for magnifying and projecting on a predetermined screen, Luminance / color signal separation means for receiving a composite video signal and separating the luminance signal and the color signal; Synchronization signal separation means for receiving the luminance signal and separating vertical and horizontal synchronization signals; Demodulation / correction means for receiving the luminance signal and the color signal, demodulating them, and correcting the luminance signal; Sequential scan conversion means for receiving the vertical and horizontal synchronization signals and the demodulated and corrected signals sequentially and converting the received signals; Matrix means for receiving the sequential scan converted signal and generating a primary color signal; Signal selection means for receiving vertical and horizontal synchronous signals from the primary color signal and the sequential scan conversion means, primary color signals and vertical and horizontal synchronous signals from the outside, and selecting and outputting them; Liquid crystal interface means for interfacing the selected primary color signal in response to the selected vertical and horizontal synchronization signals; Liquid crystal control means for receiving the selected vertical and horizontal synchronization signals from the signal selection means and outputting a timing control signal; And an R, G, and B signal liquid crystal display devices for receiving the R, G, and B signals of the interfaced primary color signals, respectively, in response to the timing control signal, to enlarge and project the R, G, and B signals. The liquid crystal display of claim 1, wherein the R, G, and B signals include: a panel; Gate driving means having a shift register for connecting each pixel of the panel; And a source driving means and applying a reset signal to a part of the gate driving means connected to a pixel located on a predetermined vertical line of the panel to remove a pulse remaining in the shift register. Device. The liquid crystal projection apparatus according to claim 1, wherein the sequential scan converter converts the frequency of the vertical synchronization signal to 31.5 kHz and compresses the demodulated and corrected signal to 1/2 on the time axis.