JP2591161B2 - Color display data control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] The present invention relates to a color display data control method in a color display device of a three-color cell juxtaposition type in which one pixel is constituted by RGB three-color cells capable of three-tone display. The purpose is to make it possible to display 16 colors by using a digital RGB interface signal with a luminance signal that switches the lighting state between two levels of light and dark. A color display device in which each of the cells performs a three-gradation display of a non-lighted state, a dark state, and a bright state, based on a luminance signal given from the device and display data indicating whether the cell is turned on or off for each cell. A black display detecting means for detecting any one of a black state of a bright state and a dark state from the luminance signal and display data for each cell; and a detection output of the black display detecting means. The display state of each cell in time or space control, comprising a display control means for forming a different display state from any of the color of the bright state and the dark state, the display data _{(D R, D G, D} B ) Is in a non-lighting state, and is displayed in gray when the luminance signal is in a bright state, and is displayed in black when the luminance signal is in a dark state.

[Industrial applications]

The present invention relates to a color display data control method in a color display device of a three-color cell juxtaposition type in which one pixel is constituted by cells of three colors of RGB capable of displaying three gradations.

2. Description of the Related Art In recent years, personalization of OA equipment has progressed, and there is a strong demand for a thin, low-cost display to be mounted on a laptop personal computer or the like. Above all, simple matrix type LC
D (Liquid Crystal Display) is expected to become mainstream in the future because it can display black and white at low cost and is relatively easy to develop into color.

However, in this type of display, since it is difficult to perform multi-gradation display due to the driving principle, there has been a strong demand for a method of realizing 16-color display required for personal computer display with simple control.

[Conventional technology]

When Fig. 4, in the liquid crystal panel of the simple matrix structure, as shown in FIG. 5, the state turned one column all the liquid crystal display device (e.g., X ₁ row of the figure, the display of the liquid crystal which ○) was,
And one column all the liquid crystal display element non-lighting state (e.g. X ₂ columns in the figure, the display of the liquid crystal ●) illustrates when to, a driving waveform of the liquid crystal panel. In Figure 4 (a) is a data voltage, the solid line X ₁ column of the waveform applied lighting state, the dotted line shows the waveform applied non-illuminated X ₂ columns. (B) and (c)
Difference waveform applied Y ₁ row and Y ₂ rows of scan voltage, (d) is a drive voltage waveform of a cell alpha (solid line), the driving voltage waveform of the cell beta (dotted line), the data voltage and the scan voltage of each cell It is.

The drive shown in the figure is called a voltage averaging method.
Voltages having the relationship shown in FIG. 6 are applied to the selected electrode and the non-selected electrode in each row and column. Practical driving waveforms include those in which the first cycle is selected during one frame period and the second cycle is selected in the next frame, or the first cycle and the second cycle are selected every few lines. There is a switch for switching, so that a DC component is not applied to the liquid crystal to realize highly reliable driving without deteriorating the panel characteristics.

FIG. 7 shows a typical waveform example for obtaining three levels of luminance by this driving method. When (a) is not lit, (b),
(C) shows the cell applied voltage in the case of lighting.
The hatched portions in (b) and (c) are the portions added to the waveform when not lit, and are added every other frame when lit in the dark state and to each frame in the bright state. As described above, when no frame is selected in units of two frames, no light is turned on. When only one frame is selected, light is turned on in the dark state. When both frames are selected, light is turned on in the light state. That is, display can be performed with three levels of luminance.

[Problems to be solved by the invention]

Recent personal computers use displays that display 16 colors using a digital RGB interface with an intensity signal. If the 16 colors are to be realized by the above-described three-gradation color liquid crystal display, there are the following problems.

The signals D _R , D _G , and D _B indicating the three display data are binary signals instructing lighting and non-lighting corresponding to the color display cells. The number of colors that can be controlled by this and the binary luminance signal I indicating which of the two luminance levels to display can be controlled by a combination of lighting and non-lighting of three colors in the bright state.
Color, 3-color lighting in the dark state, becomes eight colors which can be a combination of non-lighting, D _R, D _G, black display which can be expressed when D _B are all non-lit, bright, dark either state Is the same, so only 15 colors can actually be displayed. This causes a problem that compatibility with a case where a display device such as a CRT is used cannot be obtained as it is.

The present invention provides a color display device in which one color pixel is configured by juxtaposition of cells of three colors of RGB, and each cell can switch and display three levels of luminance including a non-lighting state,
An object of the present invention is to enable display of 16 colors by a digital RGB interface signal with a luminance signal for switching a lighting state between two levels of light and dark.

[Means for solving the problem]

 FIG. 1 is a diagram for explaining the principle of the present invention.

Reference numeral 4 denotes a color liquid crystal display unit capable of displaying three gradations. Display data D _R , D _G , and D _B of three colors and luminance signals I _R , I _G , and I _{B of} the three colors are provided from outside. A horizontal sync signal H _SYNC and a vertical sync signal V _SYNC indicating the horizontal and vertical positional relationship of the screen.
Then, color display of three gradations is performed.

The present invention enables the display unit 4 to differentiate black between a bright state and a dark state in order to display 16 colors.

In the figure, reference numeral 1 denotes a black display detecting means, the luminance signal of which is one of light and dark (for example, a bright state), and display data D _R , D _G , and D _B externally applied to cells of three colors. Are all displayed in black. Reference numeral 8 denotes display control means for setting each cell to a display state different from any of the normal bright state and dark state.

The control of the display state of each cell by the display control means 8 may be either temporal control or spatial control. The illustrated example is a configuration for temporally performing display control. The detection result of the specific frame period detecting means 2 for knowing every several frame periods and the detection result of the black display detecting means 1 are shown in FIG. based on, for every frame period specified by the specifying frame period detection unit 2, the display data for each cell, the display data D _R to be different from the display state with any of the bright state and the dark state, D _G, making D _B And ON display data adding means 3.

The display control means 8 sets the display state of each cell to be different from any of the bright state and the dark state based on the detection output of the black display detecting means 1, thereby changing the display color of one black state. The display color of the other black state.

In addition, the display control means 8 is not limited to the configuration shown in the figure, but may be one that spatially controls the display state. This point will be described in detail in Examples.

(Operation)

According to the above configuration, when the display data for all the cells is black and a predetermined luminance signal (predetermined light or dark), a detection signal is output from the black display detection means 1.

This detection signal is input to the ON display data adding means 3, but if no detection signal is output from the specific frame detecting means 2, the display data D _R , D _G , and D _B are directly output to the three-gradation color display unit. 4, all three cells are in a black display state.

The specific frame detecting means 2 sends out a detection output every fixed frame, and the ON display data adding means 3 outputs the display data.
D _R, D _G, adds this to the D _B, for all of the cells in the lighting state.

Since this operation is repeated at a constant cycle, a color in which the black state and the white state are averaged over time becomes the display color.

If this process is performed, for example, in the bright state, the black in the bright state becomes a color like gray, and the display state differs between black in the bright state and black in the dark state, and the display color becomes 16 colors.

Therefore, according to the color display data control method of the present invention, the three-gradation display color display device can receive a digital RGB interface signal with a luminance signal and perform 16-color display compatible with a CRT.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to examples.

FIG. 1 is a circuit diagram showing the configuration of one embodiment of the present invention, wherein 1 is a black display detecting means, 8 is a display control means, which comprises a specific frame detecting means 2 and an ON display data adding means 3. . In the figure, the ON display data adding means 3 is simply referred to as adding means 3.

I is a luminance signal input from the outside, I _R , I _G , I _B
Is the luminance signal input to each of the three RGB cells, V
_SYNC and H _SYNC are a vertical synchronization signal and a horizontal synchronization signal.

The display data D _R , D _G , and D _B from the outside are supplied to the black display detecting means 1.
Are connected to the three force terminals of a 4-input AND gate 11 of negative logic. At the same time, the luminance signal 1 is supplied to the AND gate 11 via the inverter 12 constituting the black display detecting means 1.
Are connected to the remaining input terminals.

As a result, from the AND gate 11, the luminance signal I indicates a bright luminance state (bright state), and the display data D _R , D _G ,
D _B are all off indication signal, that is, when the sent the black display signal, and outputs a logical "1".

On the other hand, the vertical sync signal V
_SYNC is a quaternary counter constituting a specific frame detecting means.
The clock is input to 21 clock terminals, and the count is updated every frame. This count result is applied to the two-input AND gate 22, and the logic "1" is output from the output terminal thereof every four frames during the frame.

The outputs from the black display detecting means 1 and the specific frame detecting means 2 are input to a two-input AND gate 34 constituting the ON display data adding means 3, and from the output terminal thereof,
Outputs logic "1" every four frames when bright brightness is displayed and sent from black display. This output is further connected to one input terminal of three 2-input OR gates 31, 32, and 33. Is input to

Display data D _R , D _G , and D _B are input to the other input terminals of the three two-input OR gates 31, 32, and 33, respectively.

Now, all of these display data D _R , D _G , and D _B are black, that is, logic “0”. However, since logic “1” is input from the AND gate 34, three two-input OR gates 31 and 32 are provided. , 33 all become logic "1". Although not shown, this output is provided to the above-described three-tone color display unit 4 as display data D _R ′, D _G ′, and D _B ′. So in this case,
All black display data input from the outside is replaced with white display data.

As a result, in the color liquid crystal display unit of the three gradation display, even if all three display data D _R , D _G , and D _B are off signals, when the luminance signal I is logic “0” indicating a dark luminance state, Although the black display remains as it is, when the logic is "1" for displaying a bright luminance signal, the black display of three frames and the white display of one frame appear alternately, so that the display becomes gray visually. Therefore, black in the bright state and black in the dark state can be distinguished, and 16
Color display will be possible.

As described above, this embodiment is an example in which the display state is temporally controlled.

In this embodiment, the color of the black display in the bright state is
Although the example in which the display state is different from the normal black state has been described, the black display color in the dark state can be controlled. The point is that it is possible to control the display response of either the black in the bright state or the black in the dark state to make the display color different from the other.

Next, another embodiment of the present invention in which the display state is spatially controlled will be described with reference to FIG.

In this embodiment, the display control means 8 includes the on-display data adding means 3 and the internal luminance signal generating means 5.

The display data D _R , D _G , and D _B from the outside are supplied to the black display detecting means 1.
Are connected to three input terminals of a 4-input AND gate 11 of negative logic. At the same time, the luminance signal I is AND gated through the inverter 12 constituting the black display detecting means 1.
11 are connected to the remaining input terminals.

When this result, the AND gate 11, and instructs the luminance signal I a bright light condition, and the display data D _R, D _G, all D _B OFF display signal, i.e., that sent the black display signal, logic " Outputs 1 ". This output is output to the internal luminance signal generating means 5.
, And is connected to a two-input AND gate 52. The other input of Andogedo 52 is connected to the luminance signal I from the outside, its output is brighter luminance state indicated, and when came the black display data, the luminance switching signal I _G of the green display The instruction for the dark brightness state has been changed. Luminance switching signal I _R ,, I _B of the other red and blue,
The luminance switching signal I from the outside is input as it is.

On the other hand, the output of the AND gate 11 is input to two two-input OR gates constituting the ON display data adding means 3, and when a bright luminance display state is indicated and when black display data comes, red and green are output. of the display data D _R ', D _G' is changed to the oN display data.

As a result, when black display data is received under the above-mentioned condition, that is, when instructing a bright luminance state, a mixed color of red in a bright state and green in a dark state is displayed. The black display state will be different. Therefore, also in this embodiment, display of 16 colors is possible.

At this time, as for the color combinations, at least two of the three colors need only be light and dark on display, and the remaining one color may be either light or dark on or off. Colors are available.

As described above, in the present invention, when the display data is all black, in either the bright state or the dark state, the display state is temporally or spatially controlled to control the light state and the dark state. As a display state different from any of the 15 colors formed by the combination of three colors, the display colors of black in the bright state and black in the dark state are made different from each other, thereby enabling 16-color display.

The luminance signal in the above description may be referred to as a luminance switching signal.

〔The invention's effect〕

As described above, according to the present invention, with the addition of a simple circuit, a digital RGB interface signal with a luminance signal can be received to display 16 colors, and a display unit compatible with a CRT can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention, FIG. 2 is a diagram illustrating the configuration of one embodiment of the present invention, FIG. 3 is a diagram illustrating the configuration of another embodiment of the present invention, and FIGS. Fig. 5 is a diagram showing drive voltage waveforms of the cells α and β in Fig. 5, Fig. 5 is a diagram showing an example of a display pattern, Figs. 6 (a) and (b) are diagrams showing a voltage averaging method, and Fig. 7 (a). FIGS. 7A to 7C are diagrams illustrating waveform examples for obtaining three-level luminance. In the figure, the black display detecting means 1, a specific frame detection means 2, the ON display data adding means 3, the three gradations color display unit 4, an internal luminance signal generating means 5, display control unit 8, D _R , D _G , D _B are display data given from outside,
D _R ′, D _G ′, and D _B ′ represent display data input to the three-gradation color display unit, and I represents a luminance signal.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tetsuya Kobayashi 1015 Ueodanaka Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Kazuhiro Takahara 1015 Kamiodanaka Nakahara-ku Kawasaki City, Kanagawa Prefecture 56) References JP-A-63-34593 (JP, A) JP-A-63-70893 (JP, A)

Claims (3)

(57) [Claims] 1. A color pixel is formed by juxtaposing cells of three colors, and a luminance signal (I) supplied from the outside and display data (illumination / non-illumination) for each of the cells indicate the on / off state of the cell. D _R , D _G , D _B ), wherein each of the cells performs a three-gradation display of a non-lighting state, a dark state, and a bright state based on the luminance signal and display data for each cell. A black display detecting means (1) for detecting one of a black state and a dark state; and controlling the display state of each cell temporally or spatially based on a detection output of the black display detecting means. Display control means (8) for forming a display state different from any of the colors of the state and the dark state, wherein the display data (D _R , D _G , D _B ) is in a non-lighting state and the luminance signal is in a bright state. Display gray when there is a signal, and display black when the luminance signal is dark. A method for controlling color display data, characterized in that: 2. The control of color display data according to claim 1, wherein said display control means is a temporal display control means for turning on each of said cells every predetermined number of frames. Method. 3. The display control means (8) is a spatial display control means for setting at least one of the three cells to a bright display state and at least one to a dark display state. Item 4. The method for controlling color display data according to Item 1.