JPH1010517A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compatibly realize display by the increase of the number of colors for a color picture and many picture elements with high resolution for a black- and-white image. SOLUTION: A color display means 12 displays the color image by making the aggregation of the plural display elements of a liquid crystal panel 16 correspond to one color picture element data, for example, by arranging plural sets of combination of color components RGB as one color picture element 1. A black-and-white display means 14 displays the black-and-white image by using a black-and-white picture element 2 where plural display elements which become white by the synthesis of the color components RGB correspond to the black- and-white picture element 3 corresponding to the display element for white out of plural display elements constituting the color picture element 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device which receives image data from a host device such as a host computer and displays an image on a display or a projector using a liquid crystal panel. A display using a liquid crystal panel is widely used in information devices such as a portable personal computer and a word processor due to characteristics such as thinness, low power consumption, and low voltage. In recent years, with the spread of notebook personal computers, liquid crystal projectors that can perform presentations by enlarging and projecting the personal computer screen have begun to spread.

[0002] These liquid crystal displays and liquid crystal projectors are required to have further improved image quality, that is, to be bright and easy to see, have high resolution, and have improved color reproducibility. For this reason, technological developments such as improvement of the aperture ratio of pixels, improvement of a light source, use of a liquid crystal panel that does not use polarized light, development of a high-resolution liquid crystal panel, and improvement of characteristics of a color filter are being advanced.

[0003]

2. Description of the Related Art In a conventional display device such as a liquid crystal display or a liquid crystal projector, TN is used as a liquid crystal panel.
(Twisted Nematic) mode display and TFT (Thin Film T)
A TFT liquid crystal panel combined with active matrix driving by a ransistor is often used. This TF
The T liquid crystal panel has features such as high contrast display, high gradation display, and high speed display capable of displaying moving images.

In the TFT liquid crystal panel, when the number of pixels is increased, the process is complicated and the yield is deteriorated.
As a result, at present, only about 1280 × 1024 pixels can be formed. Actually, in a current notebook-type personal computer, a liquid crystal panel having almost 640 × 480 pixels is used. Further, since a polarizing plate is used due to the characteristics of the liquid crystal material, the transmittance is as low as about 20% for monochrome and about 5% for color. As a result, only about half or less of the total light amount of the light source can be used, and the screen becomes dark. Therefore, a bright backlight is required, and the power consumption is increased.

As described above, the TFT liquid crystal panel has a maximum number of pixels of about 1280.times.1024. Therefore, when a document or table is displayed on a display or projected by a projector, the resolution is too low to display the entire A4 document. That is, 1
The number of pixels per character is reduced, and the characters are blurred and difficult to read. Therefore, the characters are enlarged and displayed, and therefore, the A4 document must be divided and displayed on a plurality of screens, and there is a problem that it is difficult to read. Further, since a polarizing plate is required, there is a problem that the transmittance is low and the screen is dark.

In order to solve this problem, it has been proposed to use a liquid crystal panel which can easily realize a large number of pixels and does not require a polarizing plate.
As a specific multi-pixel, high-resolution liquid crystal panel, for example, a phase change type liquid crystal panel can be considered (for example, Mochizuki
Other, Super High Information Content Projection Displ
ay Using an NCPT Liquid Crystal, FSTJ, vol 28,3, p
p369-376, 1992.).

It has been confirmed that this phase change type liquid crystal panel has a multi-pixel size of up to 3500 × 2500 pixels in an A4 size. Further, a bright screen with a transmittance of 60% or more can be realized. However, rewriting of a phase transition type liquid crystal panel is slower than several seconds and several tens of milliseconds of a CRT or the like, and gradation display cannot be performed. Therefore, binary display similar to a printer is performed. Therefore, in order to achieve gradation display, the number of expression colors is artificially increased using a color filter.

For example, in Japanese Patent Application Laid-Open No. 4-371923, FIG.
As shown in FIG. 3, one color pixel is constituted by a combination of four display elements to which four colors of RGBW (red, green, blue, and white) are assigned by a color filter. As shown in FIG. A method of expressing halftones by color mixture by combination is disclosed. In this case, the number of display colors is such that one display element can represent two gradations of ON and OFF,
Since there are four elements, 2 × 2 × 2 × 2 = 16 colors.

In the case where one color pixel is composed of nine elements in which three elements to which RGB color components are allocated vertically and horizontally are arranged vertically and horizontally, for example, one set of RGB3 elements is a combination of ON and OFF. That is, (the number of on and the number of off) are (0, 3), (1, 2), (2, 1), and (3, 0).
(4 gradations), it is possible to represent 4 × 4 × 4 = 64 colors and many halftones.

[0010]

However, when the number of colors to be expressed is artificially increased by using such a conventional color filter, even if the liquid crystal panel is a multi-pixel phase-change liquid crystal panel, four display elements are required. When one color pixel is formed by the above, the actual number of color pixels is halved to 1750 × 1250 pixels. Further, when one color pixel is constituted by nine display elements, the number of colors that can be expressed increases to 64 colors, but the number of color pixels decreases to 1166 × 833, which is one third, which is the same as a TFT liquid crystal panel. I will.

In this case, not only a color image but also a black and white character image is displayed with the same number of pixels as the number of color pixels. There is a problem that it is difficult to display a detailed document. The present invention relates to a liquid crystal panel that performs pseudo-gradation display using a color filter, and an image that can satisfy both contradictory conditions of displaying a color image with a large number of colors and displaying a monochrome image with high-resolution multi-pixels. It is an object to provide a display device.

[0012]

FIG. 1 is a diagram illustrating the principle of the present invention. First, as shown in FIG. 1A, the present invention is directed to an image display device using a liquid crystal panel 16 that displays characters, images, and the like by combining a plurality of display elements. According to the present invention, as such an image display apparatus, one color pixel data is associated with a predetermined number of liquid crystal panels 16, for example, 3 × 3 nine elements as shown in FIG. Color pixels 1 in which a plurality of combinations of color components RGB having different color spaces are arranged by a color filter.
A color display means 12 for displaying a color image; a monochrome pixel 3 in which data of one monochrome pixel is associated with a monochrome display element among a plurality of display elements constituting the color pixel 1;
And a black-and-white display means 14 for displaying a black-and-white image by black-and-white pixels 2 corresponding to display elements for a plurality of colors which become white by RGB color synthesis.

In general, when comparing the appearance of the human eye between a color image and a black-and-white character image, it does not matter that the color image is not so high in resolution. Is difficult to see. The present invention takes advantage of this property of humans.
That is, in the present invention, a color image is displayed by combining a set of color components RGB by a plurality of display elements with one as in the related art.
A color image having a plurality of gradations is displayed as one color pixel 1. On the other hand, in the black-and-white image, one display element obtained by dividing the color pixel 1 or a plurality of display elements which become white due to color recognizing is displayed as the black-and-white pixel 2 or 3 to increase the number of pixels of the black-and-white image.

For example, as shown in FIG.
When the color pixel 1 including the B component is configured to express 108 colors, as shown in FIG.
One monochrome pixel 2 is formed. That is, the black-and-white pixels are two pixels in each of the main scanning direction (horizontal direction) and the sub-scanning direction (vertical direction), and the number of black-and-white pixels is three-thirds for three display elements. .

As a result, assuming that the number of display elements of the display panel 16 is N × M pixels in the vertical direction and M in the horizontal direction, the number of pixels of the color image and the monochrome image is as follows: Color image: (N / 3) × (M / 3) pixels • Black and white image: (N / 1.5) × (M / 1.5) pixels.

For this reason, conventionally, both color images and black-and-white images have (N / 3) × (M / 3) pixels. However, the present invention provides a monochrome display with the same number of expressible colors. Images can be displayed with higher resolution than before. For example, when the number of pixels of the liquid crystal panel 16 is 3500 × 2500 pixels, the number of pixels of a color image is 1166 × 833 pixels, which is the same as the conventional case, but the display of a monochrome image is twice as large as 2333 × 1.
666 pixels. In this case, the pitch of the display elements is sufficiently small, for example, about 60 μm, and the color components RGB of the three display elements appear white to human eyes. Therefore, three display elements of RGB and one display element of white component W can be treated as one monochrome pixel.

In the present invention, the number of vertical and horizontal pixels of a color image displayed on the liquid crystal panel 16 by the color display means 12 and a monochrome image displayed on the liquid crystal panel 16 by the monochrome display means 14 change. Therefore, the present invention provides a changing means for changing the number of vertical and horizontal pixels of a color image or a black and white image displayed on the liquid crystal panel 16. For example, in the case of the black-and-white image shown in FIG. 1C, the number of pixels of the black-and-white image is doubled in both the main and sub scanning directions as compared with the color image.

Therefore, an interpolation process is performed to double the number of pixels in the main and sub-scanning directions of the monochrome image. Also, a thinning process may be performed to reduce the number of pixels in the main and sub scanning directions of the color image to 2/3. According to the present invention, a white component W is arranged adjacent to each of a combination of a plurality of color components RGB in addition to a combination of a plurality of color components constituted by RGB constituting color pixel data. Further, a white component is included in each of a plurality of combinations of color components constituting the color pixel data, and four color components RGBW are provided.

In this case, it is desirable to arrange the white components W evenly. In addition, among the RGB color components, a color component having the highest human eye sensitivity, for example, a green component G is evenly arranged. Further, the luminance of the display element of the white component W and the luminance of the display elements of the color components RGB other than the white component W are made different. In addition, the number of color components RGBW may be different as an arrangement of a combination of a plurality of color components RGB constituting color pixel data. In this case, it is desirable to maximize the number of white components W.

Further, according to the present invention, in order to display an image when a color image and a black and white image are mixed in one screen, it is further determined whether the input pixel data is chromatic color data or achromatic black and white data. If the color data is determined, the image data is output to the color display means 12 to display the color pixels, and if the monochrome data is determined, the image data is output to the monochrome display means 14 to display the black and white pixels.

Also in this case, when the number of vertical and horizontal pixels of the color image by the color display means 12 and the number of vertical and horizontal pixels of the monochrome image by the monochrome display means 14 are different, the changing means for changing the number of vertical and horizontal pixels of the color image or the monochrome image displayed on the liquid crystal panel 16 is changed. Is provided.

[0022]

FIG. 2 is a block diagram showing an embodiment of an image display device according to the present invention. 2, the image data display device of the present invention includes a mode selection unit 10, an RGB color data generation unit 12, a black and white data generation unit 14, and an image display unit 16. The mode selection unit 10 selects an operation mode depending on whether display data transferred from a host device such as a host computer is color data or black and white data.
B color data creation unit 12 or black and white data creation unit 14
Start For the determination of the color data or the monochrome data, for example, header information in the data file can be used.

The RGB color data creation unit 12 receives the designation of the color display mode by the mode selection unit 10, converts the display data into color data corresponding to one color pixel in the image display unit 16, and displays a color image. I do. For example, the color data has a configuration of 8 bits for each of RGB, and converts the color data of 256 gradations to, for example, 64 gradation data of 4 bits for each of RGB to form a plurality of pixels constituting one color pixel in the image display unit 16. Create data for determining whether the display element is on or off.

The black-and-white data creation unit 14 includes an image display unit 16
The image data for turning on and off the black and white display pixels obtained by dividing one color pixel in. As the image display section 16, for example, a phase transition type liquid crystal panel is used, and the number of pixels is, for example, 3500 × 2500 pixels. FIG. 3 shows the image display unit 1 in the embodiment of FIG.
16 is a first embodiment of a correspondence relationship between color pixels and monochrome pixels and display elements in the liquid crystal panel of No. 6;

FIG. 3A shows a correspondence relationship between the color pixels 1 and the display elements. One color pixel 1 is composed of three 3 × 3 display elements, three in the main scanning direction and three in the sub-scanning direction. ing. In the color pixel 1 using these nine display elements, color filters are arranged so that RGB color components are arranged vertically and RGB. When such nine display elements constitute a color pixel 1 capable of gradation display by RGB color components, four gradations can be represented by a combination of ON and OFF of the three display elements of RGB color components. , Since there are three sets, 1
One color pixel 1 can represent 4 × 4 × 4 = 64 colors.

On the other hand, the number of pixels of a color image on the liquid crystal panel is reduced to one third since one display pixel constitutes one display pixel. For example, the image display unit 1
6, the number of pixels of the phase transition type liquid crystal panel is 3500 × 2500
If it is a pixel, the number of pixels of the color image is 1/3 of 1166 × 833 pixels. FIG. 3 (B) is FIG. 3 (A)
FIG. 3 is an explanatory diagram of a black-and-white pixel formed by dividing a color pixel 1 of FIG. In this embodiment, for the three sets of RGB components forming the color pixel 1, the monochrome component 2 is made to correspond to the RGB components in the sub-scanning direction (vertical direction) as one set. 3 black and white pixels inside
Are formed separately.

That is, FIG. 3 composed of nine display elements
Regarding the color pixel 1 shown in FIG. 2A, the monochrome pixel 2 has three pixels in the main scanning direction (horizontal direction) and one pixel in the sub-scanning direction (vertical direction).
Since / 3 is one pixel, the number of black and white pixels obtained by dividing one color pixel 1 is (3/3) × (１ ／) = 3 pixels. As a result, in a phase change type liquid crystal panel having a display element of 3500 × 2500 pixels in the image display device 16, a monochrome image of 3500 pixels in the main scanning direction × 833 pixels in the sub-scanning direction is displayed.

As described above, in the embodiment of FIG.
A black-and-white image can be displayed with a high resolution of 3500 × 833 pixels in contrast to a color image of 1166 × 833 pixels capable of expressing four colors. FIG. 4 shows a second embodiment of the image display device according to the present invention. As the number of pixels for displaying a black and white image is increased, the aspect ratio of the image is changed between a color image and a black and white image. It is characterized in that it is prevented from being lost.

In FIG. 4, the mode selection unit 10, RGB
The color data creation unit 12, the black-and-white data creation unit 14, and the image display unit 16 are the same as those in the embodiment shown in FIG. 2. In addition, a sub-scanning direction pixel number conversion unit 18 is added before the monochrome data creation unit 14. Is provided. In the display according to the color pixel 1 of FIG. 3A for displaying a color image and a monochrome image in the embodiment of FIG. 2 and the monochrome pixel 2 of FIG. The number of elements used for display in the scanning direction (vertical direction) is the same as three, but the number of elements used for display in the main scanning direction is three for color pixels 1 and one for black and white pixels 2.
Since the number of black and white pixels is three times the number of color pixels, the black and white pixels are vertically long, and if this is the case, the aspect ratio of the original display image changes, and the shape of the image differs from the original image.

For example, when a circle is displayed by the color pixels 1 in FIG. 3A, when the same circle is displayed by the monochrome pixels 2 in FIG. 3B, the circle becomes a vertically long ellipse.
Therefore, in the sub-scanning direction pixel number conversion unit 18 in FIG.
Since the number of elements used for display by black and white pixels is reduced to 1/3 in the main scanning direction compared to the color pixels, the number of pixels in the sub-scanning direction of the original image data is correspondingly reduced to 1/3. A thinning process is performed.

The number of pixels (the number of lines) in the sub-scanning direction is reduced to 1/3
As a method of performing the thinning process, a method of simply discarding two pixels out of three pixels and leaving only one pixel, a method of calculating an average value of the values of three pixels, and replacing the calculated value with the calculated value can be considered.
As a method of leaving only one pixel, as shown in FIG. 5A, the entire image is scanned as a count value (x) in the main scanning direction and a count value (y) in the sub-scanning direction. Just leave. As a result, the number of pixels in the main scanning direction does not change, and the number of pixels (number of lines) in the sub-scanning direction is １ ／.
Reduced to The image is substantially reduced in the vertical direction. When this is displayed by vertically long pixels as shown in FIG. 3B, the image can be viewed as an image having the same aspect ratio.

The method of switching from the average value of the three pixels is as follows.
As shown in FIG. 5B, for each pixel of the line in the sub-scanning direction, three lines of pixels, for example, pixels a,
The average value of b and c is calculated, and three pixels are replaced with one pixel of the average value. In this case as well, the number of pixels (the number of lines) in the sub-scanning direction is reduced to 1/3, but by displaying with vertically long pixels,
It has the same aspect ratio as the original image. Reverting to the average value preserves the smoothness of the image compared to simple decimation.

As a result, the difference in the length of the vertical and horizontal display pixels in the display image of the monochrome pixel 2 can be absorbed, and the change in the vertical and horizontal ratio of the display image can be compensated to display a correct image. In the embodiment of FIG. 4, the sub-scanning direction pixel number conversion unit 18 reduces the number of pixels of the monochrome image data by 1 / in the sub-scanning direction.
Although the thinning process of reducing the number of pixels to 3 is performed, the same applies to another embodiment in which an interpolation process of increasing black and white data three times in the main scanning direction is performed. In the pixel number conversion process of expanding three times, if the number of pixels is simply increased, the speed can be increased, but the image quality is not so good. Good.

The simple enlargement of the number of pixels (the number of lines) in the sub-scanning direction is such that one line is repeated three times as shown in FIG. On the other hand, the interpolation processing
As shown in (B), based on the pixel values of two adjacent lines, the value of the line to be increased so that the change is continuous is determined.
Specifically, the difference between the pixel values of the two lines is calculated and divided by three. Of the two pixel values, the value of the pixel between them is determined so that the value is equally increased by the value obtained by dividing the difference by 3 from the smaller value to the larger value. For example, the pixel values of two lines are 100 and 7
If 0, the pixels in between are 90 and 80. According to this method, the smoothness of the image is preserved compared to a simple enlargement.

FIG. 7 is a second view showing the correspondence of display pixels to color pixels and black and white pixels in the image display device of the present invention.
It is explanatory drawing of embodiment. FIG. 7A shows a color pixel 1. In this embodiment, a color pixel 1 is composed of 4 × 4 16 display elements, and 16 display elements are divided into 2 × 2 4 elements. A white component W is arranged in addition to the RGB color components in the four elements. As a result, four R
The sets of GB color components are arranged adjacent to each other and include the white component W.

A four-element array having four such RGB elements is provided.
In the color pixel 1 composed of six detection elements,
4 × 4 = 16 display pixels become one pixel. As a result, the number of pixels becomes １ ／ in both the main scanning direction and the sub-scanning direction. Specifically, taking a phase transition type liquid crystal panel having 3500 × 2500 display pixels as an example, the number of color pixels is 1/4 of 87.
This is 5 × 625 pixels.

In this case, the number of gradations that can be expressed in a color image depends on the on / off state of four elements of four color components of RGBW. , 3, 4 are obtained, and since there are four sets, 5 × 5 × 5 × 5 = 625 colors can be expressed.

FIG. 7B is an explanatory diagram of black and white pixels obtained by dividing the color pixels 1 shown in FIG. 7A. In this case, the monochrome pixel is composed of four monochrome pixels 2 obtained by simultaneously turning on and off a combination of three elements of three color components of RGB and four single display elements corresponding to the white component W. Is divided into black and white pixels 3. That is, for 4 × 4 = 16 display elements, there are four black and white pixels by the combination of RGB and W
A total of eight black and white pixels can be obtained from four black and white pixels 3 using only the components.

Accordingly, the number of pixels in the main scanning direction is the same as the number of display elements of the display panel (4/4), and the number in the sub-scanning direction is half (2/4). Specifically 3500 × 250
Looking at the 0-pixel phase change type liquid crystal panel, the number of black and white pixels is 3500 × 1250 pixels, and FIG.
Can display a monochrome image having a sufficiently high resolution as compared with the color pixel.

Here, assuming that the size of the color pixel 1 in FIG. 3A is about 60 μm, the pixel pitch of the color pixel 1 is about 240 μm, that is, about 0.24 mm. Even at the pixel pitch of the display, since it is about 0.3 mm, the color pixel 1 can be seen as a sufficiently small pixel when viewed from the human eyes, and the number of color pixels 1 is one pixel with respect to the display number. Even at 875 × 625 of / 4, resolution equivalent to that of a conventional TFT liquid crystal panel can be realized.

FIG. 8 shows a third embodiment of the correspondence relationship between color pixels and black-and-white pixels in the image display device of the present invention. In this embodiment, the same color pixels and the same pixels as those shown in FIG. The arrangement of the black and white pixels is characterized in that the arrangement of the white component W is performed evenly in the 16 display elements. FIG. 8A shows a case where the 4 × 4 16 elements are divided into four elements, up, down, left and right, and two black and white pixels 2 and 3 are arranged in the four elements. The arrangement of the black-and-white pixels 2 by the three-component synthesis is the same for both of them.

By arranging the black-and-white pixels 3 composed of only the W component and the black-and-white pixels 2 composed of the RGB components evenly as described above, even if there is a difference in display area between the monochrome pixels 2 and the black-and-white pixels 3, The uniformity of the distribution of black and white pixels on the display screen can be ensured. Further, in FIG. 8A,
With respect to the display elements of the color components other than the white component W, the display element to which the color with the highest human eye sensitivity is assigned, and in this embodiment, the green component G is also arranged uniformly.

Therefore, in displaying a color image using color pixels, the green component G, which is the center of brightness among the RGB color components, is also uniform among the 16 display elements forming one color pixel. And uniformity of the color image on the display screen can be further ensured. FIG. 8B shows another embodiment of the uniform arrangement of the white component W and the green component G in FIG. 8A, and FIG.
Is an embodiment of another uniform arrangement of the white component W and the green component G.

FIG. 7B and FIGS. 8A to 8C
Are different from each other in the size of a white pixel represented by a single display element having only the white component W and white represented by a set of three elements of RGB components. Display pixel pitch is tens of microns
If it is as small as m, even if characters and lines are displayed in black and white by mixing the black and white pixels 2 with only RGB components and the black and white pixels 3 with only the W component, human eyes are hardly noticed.

However, in order to improve the quality of characters and lines in a black and white image, it is necessary to make the black and white pixel 3 by the display element of only the W component look equal to or larger than the black and white pixel 2 by the three display elements of RGB. is there. Specifically, a monochrome display pixel 2 using three display elements of RGB
The transmittance of the filter may be adjusted so as to make white in the black and white pixel 3 by only one display element of the W component lighter than white light due to. In addition to adjusting the transmittance of the filter, the area of the black and white pixel 3 may be made equal to the area of the black and white pixel 2 using three RGB elements by increasing the display element of the W component.

FIG. 9 shows a fourth embodiment of the color pixel used in the image display device of the present invention. In this embodiment, the number of colors of the four color components RGBW constituting the color pixel is not equalized. It is characterized in that it is different. For example, in FIG. 9A, one color pixel 1 is constituted by nine 3 × 3 display elements, and among the nine display elements constituting the color pixel 1, the color components G and
Two display elements are allocated to B and W, and three display elements are allocated to the R component.

In this case, the number of colors that can be expressed by the color pixel 1 is G, B, and W, with three gradations of 0, 1, and 2 by turning on and off two display elements, and turning on and off three display elements with three R components. ,
Since there are four gradations of 0, 1, 2, and 3 due to OFF, 3 × 3 × 3 × 4 = 108 colors.

By increasing the number of display elements of a specific color component, for example, the R component in the color element 1 as compared with the others, red can be displayed particularly vividly. Of course, as another embodiment, by increasing either the green component G or the blue component B other than R, green and blue can be similarly displayed vividly. FIG. 9B shows an embodiment in which the number of display elements for white component W is three, which is the largest, for two display elements for R, G, and B components. When the number of display elements of the white component W is the largest, a color image with a bright screen can be displayed as a whole.

FIG. 10 shows another embodiment in which the number of display elements of the white component W in FIG. 9B is maximized.
In addition, the color having the highest sensitivity to the human eye among the color components other than the white component W, in this embodiment, the green component G is arranged as evenly as possible.
FIG. 10A shows three W components arranged in a diagonal direction. In FIG. 10B, three white components W are arranged in one line in the main scanning direction. Further, in FIG. 10C, three white components W are dispersedly arranged at the corners. Further, FIGS. 10A to 10C show four black and white pixels 2 and 3 at four corners of black and white pixels, respectively.
Are allocated so as to be evenly arranged.

Of course, the black and white pixels are two of the black and white pixels 2 by turning on and off the three components of the RGB component and the black and white pixels by turning on and off the display element 3 of only the W component. Assigned inside. FIG. 11 shows another embodiment of the image display device of the present invention. In this embodiment, the image display device can display even when a color image and a monochrome image are mixed in the image data to be displayed on one screen. It is characterized by having done.

In FIG. 11, a color / monochrome determination section 20 is provided at the input stage. Color / monochrome determination unit 2
A value of 0 checks display data transferred from a host computer or the like in units of pixel data, and determines whether the pixel data is color pixel data or monochrome pixel data. Usually, one color pixel data is composed of, for example, 24-bit data of 8 bits for each of RGB.

Then, the difference between the three RGB 8-bit data is compared. If the difference is small, the pixel data is determined as monochrome pixel data. If the difference is large, the pixel data is determined as color pixel data. The pixel data determined to be color by the color / monochrome determination unit 20 is output to the color data creation unit 12, and the monochrome pixel data determined to be monochrome is output to the monochrome data creation unit 14, where the image display unit 16 , On / off data of the display element corresponding to the color pixel and the black and white pixel is generated.

In this case, when the color data created by the color data creation section 12 and the monochrome data created by the monochrome data creation section 14 are simultaneously displayed on the liquid crystal panel of the image display section 16, the size of each image data is reduced. Due to the difference, the original image cannot be displayed correctly.
FIG. 12A shows a color image 26 and a black-and-white image 28 of display data sent from a host computer. For example, when one color image is divided into two in the sub-scanning direction to form two black-and-white pixels, When displayed as it is, FIG.
As shown in (B), the color image 32 can be displayed correctly, but the size of the monochrome image 34 in the sub-scanning direction is reduced to half.

Therefore, by reducing the number of pixels of color data in the sub-scanning direction or increasing the number of pixels of black-and-white data in the sub-scanning direction, the size of a color image and that of a black-and-white image can be matched. In the embodiment of FIG. 11, by reducing the number of pixels of color data to, for example, １ ／ in the sub-scanning direction,
Image display unit 1 displays black and white data and color data of the same size.
6 can be displayed on the liquid crystal panel.

In the above embodiment, one color pixel is constituted by 9 display elements of 3 × 3 or 16 display elements of 4 × 4, but one color pixel is constituted. The number of display elements to be formed is not limited to this, and can be an appropriate number of display elements. Further, the image display device of the present invention may be used as a display, or may constitute a projector device using a liquid crystal panel.

[0056]

As described above, according to the present invention, for a display device such as a phase change type liquid crystal panel which has high resolution but cannot perform gradation display, the number of display colors of a color image is, for example, about 100. And an image display device that achieves both high resolution when displaying a black and white image.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a block diagram of an embodiment of a basic device configuration of the present invention.

FIG. 3 is an explanatory diagram of a first embodiment of a correspondence relationship between a color pixel and a monochrome pixel with respect to a display element;

FIG. 4 is a block diagram of an embodiment having a pixel number changing function according to the present invention;

FIG. 5 is an explanatory diagram of a pixel number thinning process in FIG. 4;

FIG. 6 is an explanatory diagram of an enlargement process by pixel number interpolation in FIG. 4;

FIG. 7 is an explanatory diagram of a second embodiment of a correspondence relationship between a color pixel and a monochrome pixel with respect to a display element.

FIG. 8 is an explanatory diagram of an embodiment of the uniform arrangement of white components W in FIG. 7;

FIG. 9 shows a third example of a correspondence relationship between a color pixel and a display element.
Explanatory diagram of the embodiment

FIG. 10 is an explanatory diagram of an embodiment of the uniform arrangement of green components G in FIG. 9;

FIG. 11 is a block diagram of an embodiment of the present invention for displaying a color image and a monochrome image on the same screen.

FIG. 12 is an explanatory diagram of image data and a display screen in FIG. 11;

FIG. 13 is an explanatory diagram of a correspondence relationship between a color pixel and a display pixel in which halftone is artificially increased by a conventional color filter.

[Explanation of symbols]

 1: color pixel 2: monochrome pixel (RGB display element) 3: monochrome pixel (W display element) 10: mode selection section 12: RGB color data creation section 14: monochrome data creation section 16: image display section (phase change type liquid crystal) panel)

Claims (7)

[Claims] 1. An image display apparatus using a liquid crystal panel for displaying characters, images, and the like by combining a plurality of display elements, wherein one color pixel data is associated with a predetermined number of display elements of the liquid crystal panel. A color display means for displaying a color image by color pixels in which a plurality of combinations of different color components are arranged by a color filter on each display element; and a plurality of displays constituting the color pixels in one monochrome pixel data A black-and-white display means for displaying a black-and-white image by black-and-white pixels corresponding to display elements for white among the elements and display elements for a plurality of colors that become white by color synthesis. . 2. An image display apparatus according to claim 1, further comprising an aspect ratio of a color image displayed on said liquid crystal panel by said color display means and a monochrome image displayed on said liquid crystal panel by said monochrome display means. An image display device comprising: a changing unit that changes an aspect ratio of a color image or a black-and-white image displayed on the liquid crystal panel so that the aspect ratios of the two images are the same. 3. The image display device according to claim 1, wherein a white component is arranged adjacent to each of the combinations of different color components constituting said color pixel data. 4. The image display device according to claim 1, wherein, among combinations of different color components, color components having the highest sensitivity to human eyes are evenly arranged. 5. The image display device according to claim 1, wherein the luminance of a single display element for displaying a white component and the luminance of a display element for displaying each color component by combining different color components are different. An image display device characterized by the above-mentioned. 6. An image display device according to claim 1, wherein the number of each color component is different for a plurality of combinations of different color components constituting said color pixel data. apparatus. 7. The image display device according to claim 1, further comprising determining whether the input pixel data is chromatic color data or achromatic black-and-white data, and determining the color data when the color data is determined. An image display device for outputting a color image by outputting the black and white data to the black and white display device when the black and white data is determined.