JPH0756549B2 - Color display device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a color display device in which full-color display is performed by arranging color filters on a plane and controlling the amount of light passing through the color filters.

[Prior Art] Conventionally, there has been a strong demand for flat displays such as full-color images and color graphics. Against this background, recently, there have been active attempts to realize a color display by using a liquid crystal display as a light valve and combining it with a planar array color filter. Especially for liquid crystal displays,
TFT (thin bullet transistor) and MIM (metal-insulator-metal)
Elements of the structure are placed in each pixel. So-called active
The combination with the matrix method enables a display with excellent contrast, and the combination with the color filter has attracted attention as a flat display with good image quality. It is possible to realize colorization by combining it with a color filter, even without using a liquid crystal display, a solid such as PLZT, or a combination with a fluorescent display or a CRT, but at present, liquid crystal is most possible. Has sex.
FIG. 1 and FIG. 2 show an array pattern of color filters applied to such a display body, and Rs are circled so that the patterns are easy to understand. Usually, like this, the three primary colors R,
G and B are arranged in a plane.

Fig. 1 is a pattern called diagonal arrangement, which was devised to increase the resolution. However, the diagonal arrangement of falling to the right or falling to the left is easy for the human eye to see, and it may be strange when the number of pixels is small. Not very good. This phenomenon is largely due to the symmetrical pattern. FIG. 2 shows an example of stripe arrangement. This is perceived by the human eye as if the number of pixels is the same as in FIG. 1 and the resolution is lowered.
Therefore, in order to raise the resolution to a predetermined level, the number of pixels is required to be several times larger than that of the diagonal arrangement, which makes the fabrication of a flat panel such as a liquid crystal display considerably difficult.

〔Purpose〕

Therefore, an object of the present invention is to provide a pattern in which the resolution is enhanced even with a small number of pixels, and at the same time, the array pattern of filters is difficult to recognize.

〔Overview〕

FIG. 3 shows an outline of the present invention. In order to make it difficult for the human eye to recognize the pattern of the filter array,
The left and right sides of the diagonal arrangement pattern in the figure are folded back at regular intervals. It is assumed that the display body is composed of a (M × N) matrix having N columns in the X direction and M rows in the Y direction. At this time, when focusing on only the R marked with a circle, a diagonal array of downward rightward (downward left) up to n rows is formed along the Y direction. Contrary to the n-th row, the diagonal rows are folded back to the left row (downward right) from the m-th row. Then, from the line next to the m-th line, it folds downward to the right (down to the left). In this way, by repeating the falling downward and the falling right at regular intervals, a pattern that meets the object of the present invention can be obtained. An array in which n and m are equal is the best, but an array conforming to this may be used depending on the number of pixels. Also, with R as the reference, this example must be G and B to the right
It's lined up, but the opposite is also possible, or toward the right side
It is more effective to combine the R, G, B sequences with the R, B, G sequences.

〔Example〕

FIG. 4 shows a more specific filter arrangement pattern.
This is an example in which the downward sloping and the downward sloping are folded line by line. (N =
m = 2) In the same number of pixels (same matrix size) as in the case of FIG. 1, both numerical resolutions are as good as each other, but in the case of FIG. Since the array is hardly recognizable, the resolution is visually perceived to be higher than that in FIG.

In contrast to such a planar arrangement of color filters, the display body side, which is a light valve, is driven by respective color signals so that each pixel at each color position of the color filters such as R, G, B corresponds to one to one. There is a need to. FIG. 5 shows an example of driving the display body. It is composed of a row driving circuit 1 and a column driving circuit 2, and each driving circuit includes a shift register which is sequentially selected by clocks CLX, CLY and start pulses SPX, SPY. The display data inputs V ₁ , V ₂ and V ₃ are the same as those when the color signals are processed in parallel in the drive circuit 2 and V ₁
There are two cases in which each color signal is input in series with V ₂ and V ₃ being common. In any case, in the present invention, the column drive outputs X1 to XN
Must switch the three outputs of R, G, and B depending on the time when the row line is selected, and requires some sort of ingenuity.

Specific examples of color signal driving in which each color signal is processed in parallel by the column driving circuit 2 are shown in FIGS. Here, the parallel processing means that each color signal is input in parallel to the column driving circuit 2 and, for example, Y
The signal of V ₁ is always X ₁ , X ₄ , X ₇ ……, V ₂ regardless of the selected position of
That is, the signal of is output to X ₂ , X ₅ , X ₈ ..., V ₃ is output to X ₃ , X ₆ , X ₉ .... In this case, for each line selection, for example
Since the output of X ₁ changes in the order of R → B → G → B → R, the corresponding signal of V ₁ must also change to V _R → V _B → V _G → V _B → V _R. Where V _R is the display signal corresponding to R
The same applies to V _B and V _G. FIG. 6 shows a switch matrix circuit for recombining the color signals. Transistor switches 3 to 11 such as CMOS are sequentially switched for each row by control signals C ₁ , C ₂ and C ₃ . FIG. 7 shows the timing at this time. Again, the R, G, and B color signals are shifted to V ₁ , V ₂ , and V ₃ row by row in correspondence with the filters as shown in the figure. In the case where the color filters are arranged in a simple diagonal arrangement as shown in FIG. 1, the control signals C _{1 to} C ₃ of the switches are 1/3 divided waveforms complementary to each other, but in the case of the folded diagonal arrangement of the present invention. It is formed by 1/2 dividers 25 and 26 and AND gates 27 and 28 as shown in FIG.

9 to 11 show an operation example when each color signal is serially input in terms of time. The serial input means a state in which V ₁ , V ₂ and V ₃ become one color multiplex signal V _{I in} the signal input section of FIG. FIG. 9 shows a color signal multiplex circuit, in which any one of V _R , V _B , and V _G is selected by the switches 30 to 32 formed of transistors and is output as V _I. This V _I starts from R as shown in the arrangement of FIG. 5 when the first row of Y is selected as shown in FIG.
B, R, G, B are made up one by one in sequence. On the other hand, the second line is from B,
The color display signal of the column signal X ₁ which starts from the G in the third row must be switched every row selection. Therefore, as shown in FIG. 11, a circuit for presetting row by row is added to the 1/3 frequency divider 35. The two 1/2 dividers 33 and 34 count each row by CLY and generate a 1/4 repetitive waveform like C ₁ , C ₂ and C ₃ in FIG. This output is put into the preset input of the 1/3 frequency divider 35 and preset for each CLY. This output is output by the decoder 36 to C ₁ , C ₂ , C ₃
Since it is converted to, a 1/3 selection waveform with a different phase is always obtained. In the simple diagonal array shown in FIG. 1, the outputs of the frequency dividers 33 and 34, which are the preset inputs of the 1/3 frequency divider, may be simple 1/3 frequency division outputs, but as in the present invention, the folded diagonal line is used. The array requires a large frequency division output at the points shown in FIG.

[Effects] The present invention makes it possible to improve the apparent resolution because the array pattern of the filter is less visually perceptible even with a smaller number of pixels than in the past, and the higher the number of pixels, the higher the resolution. This contributes to the resolution improvement and can secure sufficiently good display quality not only in the image display but also in the graphic mode and the character mode necessary for the terminal for the computer.

[Brief description of drawings]

1 and 2 show a conventional color filter array. FIG. 3 and FIG. 4 are examples of color filter array patterns according to the present invention. FIG. 5 shows a driving method of a display body using the color filter of the present invention. 6 to 8 are operation examples in the case of driving the display body according to the present invention in parallel with the color signals. 9 to 11 show an operation example in the case where the display body according to the present invention is driven in series with color signals.

Claims (1)

[Claims] 1. A color display device for performing color display in which display pixels arranged in a matrix on a substrate are associated with three primary color filters, wherein each color filter of the three primary color filters has a diagonal line in a right (left) downward direction. A color display device characterized in that an array of m rows and an array of n rows in a diagonal line to the left (right) are arranged so as to be alternately and continuously repeated.