JP4011354B2 - Monochrome flat panel display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a monochrome flat panel display device, and more particularly to a monochrome flat panel display device capable of displaying a monochrome screen in which a color difference can be visually recognized when a color signal is input.
[0002]
[Prior art]
FIG. 6 is a block diagram showing an example of a conventional monochrome flat panel display device.
In this monochrome flat panel display device 500, the monochrome signal M is a display signal of, for example, 256 gradations for each pixel unit U separated from the analog or digital video input signal.
[0003]
The gamma characteristic table 4 converts the input monochrome signal M into a gradation value d that matches a desired gamma characteristic.
The liquid crystal drive circuit 6 generates a drive voltage V corresponding to the gradation value d and applies it to the subpixels S1, S2, S3 of one pixel unit U of the monochrome liquid crystal display panel 7.
[0004]
As shown in FIG. 7, the monochrome liquid crystal display panel 7 includes a large number of pixel units U arranged in a matrix. Each pixel unit U is composed of sub-pixels S1, S2, and S3.
[0005]
FIG. 8 is a block diagram showing a monochrome flat panel display device 500 ′ obtained by modifying the monochrome flat panel display device 500 so that color signals (R, G, B) can be input.
In this monochrome flat panel display device 500 ′, the red signal R, green signal G, and blue signal B are, for example, 256 gray scale red display signals and green display signals for each pixel unit U separated from the analog or digital video input signal. , Blue display signal.
[0006]
The gamma characteristic tables 4-1, 4-2, 4-3 convert the input red signal R, green signal G, and blue signal B into gradation values d1 ′, d2 ′, d3 ′ according to desired gamma characteristics. To do.
The liquid crystal drive circuit 6 generates a drive voltage V1 ′ corresponding to the gradation value d1 ′ and applies it to the sub-pixel S1 of one pixel unit U of the monochrome liquid crystal display panel 7 to drive corresponding to the gradation value d2 ′. A voltage V2 ′ is generated and applied to the subpixel S2 in the same pixel unit U, and a drive voltage V3 ′ corresponding to the gradation value d3 ′ is generated and applied to the subpixel S3 in the same pixel unit U.
[0007]
[Problems to be solved by the invention]
In the conventional monochrome flat panel display device 500, only the monochrome signal M can be input, and there is a problem that it cannot cope with the color signals (R, G, B).
[0008]
In contrast, the monochrome flat panel display device 500 ′ can input color signals (R, G, B).
However, when the red signal R, the green signal G, and the blue signal B are input at the same level, the sub-pixels S1, S2, and S3 have the same luminance, and thus the color difference cannot be recognized on the screen. is there.
For example, as shown in FIG. 9, a red bar is displayed in the R equivalent region Zr, a green bar is displayed in the G equivalent region Zg, and a blue bar is displayed in the B equivalent region Zb as shown in FIG. The entire screen becomes the same brightness, and the color difference of each bar cannot be recognized.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a monochrome flat panel display device capable of displaying a monochrome screen in which a color difference can be visually recognized when a color signal is input.
[0009]
[Means for Solving the Problems]
In the first aspect, the present invention provides a monochrome display panel (7) having three subpixels (S1, S2, S3) as pixel units (U) and pixel values (R, G, B) of three primary colors. Conversion means (1, 2, 3, 4-1, 4-2, 4-3) for converting into gradation values (d1, d2, d3) with non-identical conversion characteristics, and the gradation values (d1, d2) , D3), and driving means (6) for driving the sub-pixels (S1, S2, S3) of the monochrome display panel (7) with driving voltages (V1, V2, V3) corresponding to d3). A monochrome flat panel display device (100) is provided.
In the monochrome flat panel display device (100) according to the first aspect, the pixel values (R, G, B) of the three primary colors are converted into gradation values (d1, d2, d3) with different conversion characteristics. Even if the pixel values (R, G, B) of the three primary colors are the same, the gradation values (d1, d2, d3) are different values. Therefore, the luminance of the subpixels (S1, S2, S3) varies depending on the color, and the difference in color can be recognized on the screen.
[0010]
In a second aspect, the present invention provides the monochrome flat panel display device (100) configured as described above, wherein the conversion means (1, 2, 3, 4-1, 4-2, 4-3) is 3 When the primary color pixel values (R, G, B) are the same, the ratio of the gradation values (d1, d2, d3) is calculated from the three primary color pixel values (R, G, B) by the NTSC weighted average method. A monochrome flat panel, which is converted so as to have a ratio of weighting factors (k1, k2, k3) to be multiplied by the pixel values (R, G, B) of each primary color in the case of gray scale. A display device (100) is provided.
In the monochrome flat panel display device (100) according to the second aspect, when the pixel values (R, G, B) of the three primary colors are the same, the ratio of the gradation values (d1, d2, d3) is Conversion is performed so that the ratio of the weight coefficients (k1, k2, k3) according to the NTSC (National Television System Committee) system weighted average method, that is, about 0.3: about 0.6: about 0.1. As a result, it is possible to realize conversion suitable for human visual characteristics (for example, a characteristic that responds sensitively to green luminance and does not respond very much to blue luminance).
[0011]
In a third aspect, the present invention relates to a monochrome flat panel display (100) configured as described above, wherein the monochrome display panel (7) is a liquid crystal display panel. An apparatus (100) is provided.
In the monochrome flat panel display device (100) according to the third aspect, a monochrome liquid crystal display panel excellent in luminance and contrast ratio can be configured.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the drawings. Note that the present invention is not limited thereby.
[0013]
-First embodiment-
FIG. 1 is a configuration diagram showing a monochrome flat panel display device according to a first embodiment of the present invention.
The monochrome flat panel display device 100 includes a monochrome liquid crystal display panel 7 having three subpixels S1, S2, and S3 as a pixel unit U, and pixel values R (for example, 0 to 255) that can be expressed by a red signal R. Is converted to a conversion value D1 obtained by multiplying the pixel value R by a weighting factor k1, and each pixel value G (for example, 0 to 255) that can be represented by the green signal G is converted into a weighting factor k2 G conversion table 2 for converting to a conversion value D2 multiplied by, and each pixel value B (for example, 0 to 255) that can be expressed by the blue signal B is converted to a conversion value D3 by multiplying the pixel value B by a weighting factor k3. The conversion table 3, the gamma characteristic table 4-1 for converting the conversion value D1 or the monochrome signal M into a gradation value d1 that matches the desired gamma characteristic, and the conversion value D2 or the monochrome signal M A gamma characteristic table 4-2 for converting to a gradation value d2 according to the ma characteristic, a gamma characteristic table 4-3 for converting the conversion value D3 or the monochrome signal M into a gradation value d3 according to a desired gamma characteristic, Color signal (R, G, B) is input to the conversion table (1, 2, 3), but the monochrome signal M is directly input to the gamma characteristic table (4-1, 4-2, 4-3) The drive voltages V1, V2, and V3 corresponding to the gradation values d1, d2, and d3 are generated, and the sub-pixels S1 and S1 of one pixel unit U of the monochrome liquid crystal display panel 7 are generated. And a liquid crystal drive circuit 6 applied to S2 and S3.
[0014]
The weighting factors k1, k2, and k3 are weighting factors for multiplying the primary colors when the pixel values (R, G, and B) of the three primary colors are gray scaled by the NTSC weighted average method, for example, k1 = 0.3. , K2 = 0.59, k3 = 0.11.
[0015]
As shown in FIG. 2, the monochrome liquid crystal display panel 7 includes a large number of pixel units U arranged in a matrix. Each pixel unit U is composed of sub-pixels S1, S2, and S3.
In the example of FIG. 2, the subpixels S1, S2, and S3 are arranged in the horizontal direction, but the arrangement direction is arbitrary (they may be arranged in the vertical direction or may be arranged in a triangular shape). .
[0016]
Such a monochrome liquid crystal display panel 7 is manufactured by omitting the color filter of the color liquid crystal display panel or applying a single phosphor.
Since one pixel unit U is composed of three sub-pixels S1, S2, and S3, an image can be displayed with high luminance and high contrast, which is suitable for applications such as medical images.
[0017]
FIG. 3 is a graph showing the relationship between the red, green, and blue pixel values R, G, and B and the drive voltages V1, V2, and V3 of the subpixels S1, S2, and S3.
The curves of the characteristics R-V1, G-V2, and B-V3 are gamma characteristics. The gamma value is, for example, 2.2. However, FIG. 3 is shown for convenience and does not accurately reflect actual gamma characteristics.
[0018]
The ratio of the drive voltages V1, V2, and V3 to the same pixel value (R = G = B) is k1: k2: k3 = 0.3: 0.59: 0.11.
[0019]
According to the monochrome flat panel display device 100, as shown in FIG. 4, a red bar is displayed in the R equivalent region Zr, a green bar is displayed in the G equivalent region Zg, and a blue bar is displayed in the B equivalent region Zb. When a color signal to be displayed is input, the R equivalent region Zr, the G equivalent region Zg, and the B equivalent region Zb are displayed with different luminances, so that the color difference can be recognized on the screen.
[0020]
When a monochrome signal M is input, a monochrome screen similar to the conventional one can be displayed.
[0021]
-Second Embodiment-
A monochrome flat panel display device 200 shown in FIG. 5 includes an R conversion table 14 and a switch 15-1 instead of the R conversion table 1, the gamma characteristic table 4-1, and the switch 5-1. A G conversion table 24 and a switch 15-2 are provided instead of the G conversion table 2, the gamma characteristic table 4-2, and the switch 5-2 shown in FIG. 1, and the B conversion table 3, the gamma characteristic table 4- shown in FIG. 3, a B conversion table 34 and a switch 15-3 are provided instead of the switch 5-1.
[0022]
The R conversion table 14 stores the combined data of the R conversion table 1 and the gamma characteristic table 4-1 shown in FIG. 1 in the upper half of the storage area, and the data of the gamma characteristic table 4-1 shown in FIG. This memory is stored in the lower half of the storage area. When the red signal R is input, the data is read from the upper half storage area, and when the monochrome signal M is input, the data is read from the lower half storage area by the switch 15-1. is there.
Further, the G conversion table 24 stores the combined data of the G conversion table 2 and the gamma characteristic table 4-2 shown in FIG. 1 in the upper half of the storage area, and the G conversion table 24 of the gamma characteristic table 4-2 shown in FIG. It is a memory that stores data in the lower half of the storage area. When the green signal G is input, the data is read from the upper half storage area, and when the monochrome signal M is input, the data is read from the lower half storage area by the switch 15-2. is there.
Further, the B conversion table 34 stores data obtained by combining the B conversion table 3 and the gamma characteristic table 4-3 shown in FIG. 1 in the upper half of the storage area, and the B conversion table 34 of the gamma characteristic table 4-3 shown in FIG. It is a memory that stores data in the lower half of the storage area. When the blue signal B is input, the data is read from the upper half storage area, and when the monochrome signal M is input, the data is read from the lower half storage area by the switch 15-3. .
[0023]
The monochrome flat panel display device 200 of the second embodiment requires fewer parts than the monochrome flat panel display device 100 of the first embodiment.
[0024]
【The invention's effect】
According to the monochrome flat panel display device of the present invention, it is possible to display a monochrome screen in which a color difference can be visually recognized when a color signal is input.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a monochrome flat panel display device according to a first embodiment.
FIG. 2 is a schematic diagram showing a display surface of a monochrome liquid crystal display panel.
FIG. 3 is a graph showing a conversion characteristic from a color input signal to a subpixel driving voltage in the monochrome flat panel display device according to the first embodiment.
FIG. 4 is a schematic diagram of a display screen when a color signal for displaying a color bar is input to the monochrome flat panel display device according to the first embodiment.
FIG. 5 is a configuration diagram showing a monochrome flat panel display device according to a second embodiment.
FIG. 6 is a block diagram showing an example of a conventional monochrome flat panel display device.
FIG. 7 is a schematic diagram showing a display surface of a monochrome liquid crystal display panel.
FIG. 8 is a configuration diagram showing an example of a monochrome flat panel display device that can input color signals.
9 is a schematic diagram of a display screen when a color signal for displaying a color bar is input to the monochrome flat panel display device shown in FIG. 8. FIG.
[Explanation of symbols]
1, 14 R conversion table 2, 24 G conversion table 3, 34 B conversion table 4 gamma characteristic table 5, 15 switch 6 liquid crystal drive circuit 7 monochrome liquid crystal display panel 7
100,200 Monochrome flat panel display device S1, S2, S3 Subpixel R Red signal G Green signal B Blue signal M Monochrome signal

Claims (4)

When the monochrome display panel (7) having three subpixels (S1, S2, S3) as the pixel unit (U) and the coefficients k1, k2, k3 are not the same, the red component of the color signal for a certain pixel unit (U) The first conversion means (1) for converting the pixel value (R) by the first coefficient k1 and converting it to the first conversion value (D1), and the second conversion value by multiplying the green component pixel value (G) by the second coefficient k2 Second conversion means (2) for converting to (D2) and third conversion means (3) for converting the blue component pixel value (B) by a third coefficient k3 to convert to a third conversion value (D3); The sub-pixel (S1) of the pixel unit (U) is driven with a driving voltage (V1) corresponding to one conversion value (D1), and the pixel is driven with a driving voltage (V2) corresponding to the second conversion value (D2). Drive the sub-pixel (S2) of the unit (U) and correspond to the third conversion value (D3) Monochrome flat panel display device being characterized in that comprising a driving means for driving (6) sub-pixel (S3) of the pixel driving voltage (V3) (U) (100). When the monochrome display panel (7) having three subpixels (S1, S2, S3) as the pixel unit (U) and the coefficients k1, k2, k3 are not the same, the red component of the color signal for a certain pixel unit (U) The first conversion means (1) for converting the pixel value (R) by the first coefficient k1 and converting it to the first conversion value (D1), and the second conversion value by multiplying the green component pixel value (G) by the second coefficient k2 Second conversion means (2) for converting to (D2), third conversion means (3) for converting the blue component pixel value (B) by a third coefficient k3 and converting it to a third conversion value (D3); First gamma conversion means (4-1) for converting the input value to the first gradation value (d1) that matches the gamma characteristic, and conversion of the second input value to the second gradation value (d2) that matches the gamma characteristic The second gamma conversion means (4-2) and the third gradation value (d ) And the third gamma converting means (4-3) for converting the pixel unit (U) with the driving voltage (V1) corresponding to the first gradation value (d1); The driving voltage (V3) corresponding to the third gradation value (d3) is driven by driving the sub-pixel (S2) of the pixel unit (U) with the driving voltage (V2) corresponding to the second gradation value (d2). ) For driving the sub-pixel (S3) of the pixel unit (U), and when a color signal is input, the first conversion value (D1) is converted to the first gamma conversion unit (4- 1) and the second conversion value (D2) is input to the second gamma conversion means (4-2) and the third conversion value (D3) is input to the third gamma conversion means (4-3). And when a monochrome signal (M) is input, the monochrome signal (M) Switching means (5-1, 5-2, 5-3) input to 1 gamma converting means (4-1), second gamma converting means (4-2) and third gamma converting means (4-3) A monochrome flat panel display device (100). The monochrome flat panel display device (100) according to claim 1 or 2, wherein the monochrome display panel (7) is a liquid crystal display panel. ). The monochrome flat panel display device (100) according to any one of claims 1 to 3, wherein the ratio of the coefficients k1, k2, k3 is about 0. . 3: About 0 . 6: About 0 . 1 is a monochrome flat panel display device (100).

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