WO2007116589A1 - Image display, image display drive method, drive program, and computer-readable recording medium - Google Patents

Abstract

A liquid crystal display (1) has a gradation level-RGBW converter (2) for creating a first white gradation and a second white gradation and is capable of expanding the number of white gradation because the first white gradation and the second white gradation created by the gradation level-RGBW converter (2) are combined on a liquid crystal panel (5) and visible as a third white gradation.

Description

 Image display device, image display device drive method, drive program, and computer-readable recording medium

 Technical field

 The present invention relates to an image display device, a driving method for the image display device, a driving program, and a computer-readable recording medium.

 Background art

 Conventionally, a liquid crystal display device is known as an image display device that can be reduced in thickness and weight. In a liquid crystal display device, for example, 1024 X 768 liquid crystal display elements (pixels) are arranged in a matrix pattern, and a corresponding video signal is input to each signal line intersecting each horizontal scanning line. You can display images with.

 [0003] In order to perform color display in such a liquid crystal display device, a sub-pixel having an R (red) filter, a sub-pixel having a G (green) filter, and a B (blue) filter are provided. It is widely known that a subpixel is used as one pixel.

 [0004] In a display device including three types of R, G, and B subpixels as described above, white gradation is expressed by matching the gradations of the R, G, and B subpixels. Yes. That is, white gradation is expressed by setting the gradation value of each sub-pixel to R = G = B. In this case, the number of white gradations that can be expressed is equal to the number of gradations of the R, G, and B sub-pixels. For example, as shown in Table 1, when the number of gradations of each subpixel of R, G, and B is 256 gradations from 0 to 255, the gradation of white is from R = G = B = 0 to R = G = B = 256 gradations up to 255.

[0005] [Table 1] Feel the eye RGB settings at that time

 White gradation R G B

 0 0 0 0

 1 1 1 1

 2 2 2 2

 3 3 3 3

 4 4 4 4

255 255 255 255

[0006] Further, as disclosed in Patent Documents 1 and 2, an image display device including W (white) sub-pixels in addition to RGB is known.

 [0007] Since the light transmittance in each of the R, G, and B subpixels is approximately 1Z3, the light that has passed through the R, G, and B subpixels is reduced to approximately 1Z3. On the other hand, since the W subpixel has a light transmission rate of approximately 1, the W subpixel does not reduce brightness.

 That is, by using the W sub-pixel, the degree to which the light from the light source is reduced by the color filter can be reduced. Therefore, the brightness can be maintained even if the amount of light from the light source is reduced, and the power consumption of the image display device can be reduced.

 [0009] Even when white gradation is displayed on an image display device including R, G, B, and W sub-pixels, the number of white gradations that can be expressed is R, G, B, and W. It was equal to the number of gradations of each sub-pixel. For example, as shown in Table 2, when the number of gradations of each subpixel of R, G, B, and W is 256 gradations from 0 to 255, the white gradation is R = G = B = W 256 gradations from = 0 to R = G = B = W = 255.

 [0010] [Table 2] RGBW setting at that time

 White gradation G B W

 0 0 0 0 0

 1 1 1 1 1

 2 2 2 2 2

 3 3 3 3 3

 4 4 4 4 4

255 255 255 255 255 Patent Document 1: Japanese Patent Application Laid-Open No. 2004-102292 (published on April 2, 2004)

 Patent Document 2: Japanese Patent Laid-Open No. 2002-6303 (published on January 9, 2002)

 Disclosure of the invention

 [0011] As described above, the above-described conventional image display device has the power to display only white gradations equivalent to the number of gradations of the R, G, B, and W sub-pixels.

 The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an image display device that realizes richer gradation expression, a drive method of the image display device, a drive program, and To provide a computer-readable recording medium.

 In the image display device according to the present invention, in order to solve the above-described problem, pixels including a plurality of sub-pixels are arranged in a matrix, and color data for each of the sub-pixels is used. An image display device that displays an image by changing the gradation of each sub-pixel, wherein the sub-pixel uses RGB color sub-pixels and at least two color data selected from the RGB colors. The first gradation is created using color data of at least two colors selected from RGB colors, including the sub-pixels of the gradation target color to be expressed. The second gradation is created using the color data in the sub-pixel, and the third gradation is created by combining the first gradation and the second gradation, and the image display device is constructed using the third gradation. It is characterized by expressing the input gradation level.

 [0014] According to the above configuration, the third gradation generated by combining the first gradation expressed by the RGB subpixels and the second gradation expressed by the subpixels of the number of gradation extension target colors. Since the input gradation level is expressed by gradation, a rich gradation expression is possible.

 [0015] Note that, as the first gradation expressed by the RGB color sub-pixels, for example, the Y gradation expressed by the R color and the G color, the R color, the G color, and the For example, the gradation of W color (white) expressed in B color. In this case, a Y-color or W-color sub-pixel may be used as the sub-pixel of the gradation number expansion target color.

[0016] Further, in order to solve the above problems, the image display device according to the present invention has pixels having sub-pixel power for each of the RGBW colors arranged in a matrix, and for each of the RGBW colors. An image display device that displays an image by changing the gradation of each of the sub-pixels according to the color data of each of the RGB colors, and uses the color data for each of the RGB colors. (1) Create a white gradation, create a second white gradation using the color data for the W color, and combine the first white gradation and the second white gradation to create a third white gradation. It is characterized by creating a tone and expressing the input gradation level of the image display device with the third white gradation.

 [0017] Then, in order to solve the above-described problem, the image display device driving method according to the present invention includes pixels arranged in a matrix form of sub-pixels for each of the RGBW colors, and for each of the RGBW colors. A method of driving an image display device that displays an image by changing the gradation of each sub-pixel according to the color data of the above, and creates the first white gradation using the color data for each of the RGB colors Processing, processing for creating the second white gradation using the color data for the W color, and processing for creating the third white gradation by combining the first white gradation and the second white gradation The input gradation level of the image display device is expressed by the third white gradation.

 [0018] According to the above configuration, the image display device according to the present invention creates the first white gradation using each color data of the RGB color among the RGBW color data, and the W color data Use to create the second white gradation. Then, the third white gradation is created by combining the first white gradation and the second white gradation to express the input gradation level of the image display device, so that the number of white gradations can be expanded. There is an effect that can be.

 Brief Description of Drawings

 FIG. 1, showing an embodiment of the present invention, is a block diagram showing a schematic configuration of a liquid crystal display device of the present invention.

 2 is a plan view showing a schematic configuration of a liquid crystal panel provided in the liquid crystal display device of FIG.

FIG. 3 is a plan view showing a schematic configuration of pixels constituting the liquid crystal panel of FIG. 2.

 FIG. 4 (a) is a plan view showing an example of the arrangement of sub-pixels in the pixels constituting the liquid crystal panel.

 FIG. 4 (b) is a plan view showing another example of the arrangement of sub-pixels in the pixels constituting the liquid crystal panel.

[FIG. 4 (c)] shows another example of the arrangement of sub-pixels in the pixels constituting the liquid crystal panel. It is a top view.

 FIG. 4 (d) is a plan view showing still another example of the arrangement of sub-pixels in the pixels constituting the liquid crystal panel.

 FIG. 5 is a block diagram showing a schematic configuration of a conventional liquid crystal module that displays an image in four colors of R, G, B, and W.

圆 6 (a)] is a plan view showing a state in which the first white gradation and the second white gradation are displayed in the pixel.

圆 6 (b)] is a plan view showing a state where the first white gradation and the second white gradation are displayed on the liquid crystal panel.

[7] FIG. 7 is a block diagram showing a main configuration of a gradation level-RGBW converter in the liquid crystal display device.

[8] State gradation level-This is a flowchart showing the flow of output gradation setting processing in RGBW transformation.

 FIG. 9 is a circuit diagram showing a schematic configuration of a gradation level-RGB W conversion circuit that realizes the gradation level-RGBW conversion by using nodeware.

 FIG. 10 is a plan view showing a schematic configuration of a pixel when the area ratio of sub-pixels is R: G: B: W = 1: 1: 1: 1Z2.

 FIG. 11 is a plan view showing a schematic configuration of a pixel when an area ratio of sub-pixels is R: G: B: W = 1: 1: 1: 2.

Explanation of symbols

 1 揿 (T 曰 table device

 2 Gradation level-RGBW change

 3 LCD module

 4 Timing controller

 5 LCD panel (3rd gradation creation means)

 6 pixels (3rd gradation creation method)

 7 LCD module

8 RGB- RGBW change ^^ 9 Timing controller

 10 LCD panel

 11 1st white gradation creating part (1st gradation creating means)

 12 Second white tone creating part (2nd tone creating means)

 13 gradation levels-RGBW conversion circuit

 14 1st white gradation creating part (1st gradation creating means)

 15 Second white tone creation part (2nd tone creation means)

 16 pixels (3rd gradation creation method)

 17 pixels (3rd gradation creation means)

 BEST MODE FOR CARRYING OUT THE INVENTION

 [Embodiment 1]

 One embodiment of the present invention is described below with reference to FIGS.

 FIG. 1 is a block diagram showing a schematic configuration of the liquid crystal display device 1 of the present embodiment. As shown in the figure, the liquid crystal display device 1 includes a gradation level-RGBW converter 2 and a liquid crystal module 3.

 Gradation level The RGBW converter 2 receives the gradation level input, converts it into color data for each of the RGBW colors (red, green, blue, white) and outputs it to the liquid crystal module 3. The gradation level-RGBW converter 2 in the liquid crystal display device 1 of the present embodiment creates the first white gradation using the color data of each of the RGB colors and uses the W color data. Create the second white gradation. Details of the gradation level-RGBW transformation 2 will be described later.

 As shown in the figure, the liquid crystal module 3 includes a timing controller 4 and a liquid crystal panel 5 (third gradation creating means). The liquid crystal module 3 displays an image based on the RGBW color data output from the gradation level-RGBW transformation 2. Note that a source driver and a gate driver (not shown) are interposed between the timing controller 4 and the liquid crystal panel 5 and are not described here because they are well known.

[0025] The timing controller 4 uses the RGBW color output from the gradation level-RGBW change ^^ 2. The display drive of the liquid crystal panel 5 is controlled based on the color data.

 The liquid crystal panel 5 displays an image based on control from the timing controller 4. Since the first white gradation and the second white gradation are combined on the liquid crystal panel 5 to create the third white gradation, a rich white gradation can be displayed. . Details of the liquid crystal panel 5 will be described later.

 With the above configuration, the liquid crystal display device 1 of the present embodiment can display an arbitrary image. In particular, the liquid crystal display device 1 has a first white gradation created using the color data for each of the RGB colors, a second white gradation created using the color data for the W color, and the power on the liquid crystal panel 5. The third white gradation is created by combining them, so that a rich white gradation can be displayed.

 FIG. 2 is a plan view showing a schematic configuration of the liquid crystal panel 5. As shown in the figure, the liquid crystal panel 5 is formed by arranging a plurality of pixels 6 (third gradation creating means) in a matrix.

 [0029] The pixel 6 includes sub-pixels of four colors R, G, B, and W as shown in FIG. The R, G, and B subpixels are provided with red, green, and blue color filters, respectively, and the W subpixel is provided with an achromatic color filter. In addition, each of the R, G, B, and W sub-pixels can express 256 gradations from 0 to 255. Note that the number of gradations of each sub-pixel is not limited to this, and can be any number of gradations. An image can be displayed on the liquid crystal panel 5 by the light emitted through the sub-pixel.

 [0030] Further, the liquid crystal display device 1 creates a first white gradation using the color data of each of the RGB colors in each pixel 6, and simultaneously creates a second white gradation using the W color data. Can do.

 That is, in each pixel 6, two kinds of white gradations are created. These two types of white gradation are visually recognized on the liquid crystal panel 5 or the pixel 6 as the third white gradation obtained by averaging the first and second white gradations.

Therefore, the liquid crystal display device 1 can express abundant white gradation as compared with the conventional liquid crystal display device.

FIG. 3 is a plan view showing a schematic configuration of the pixel 6. As shown, pixel 6 is sub-pixel R

, G, B, and W, and these sub-pixels are arranged in stripes. Note that the arrangement of the force sub-pixels showing the arrangement in the order of R, G, B, and W from the left in FIG. 3 is not limited to this. For example, as shown in FIG. 4 (a), an arrangement in any order such as an arrangement in the order of R, W, B, and G from the left is possible. In addition, as shown in FIG. 4 (b), each subpixel may be square. Even when the subpixels are square, the subpixels are not limited to the example shown in FIG. 4B, and the subpixels can be arranged in an arbitrary order.

 Further, as shown in FIG. 4 (c), the subpixels R, G, and B are arranged in a stripe shape, and the subpixels W, surrounding the subpixels R, G, and B arranged in the stripe shape are surrounded. May be formed. In addition, as shown in FIG. 4 (d), subpixels R, G, and B are arranged at a predetermined interval, and the subpixel W is arranged so that the gap and the periphery between subpixels R, G, and B are filled. Even so.

 [0036] In the sub-pixel arrangement of FIGS. 4 (c) and 4 (d), sub-pixels W are formed surrounding sub-pixels R, G, and B! Therefore, each color of R, G, and B colors The first white gradation created using the data and the second white gradation created using the W color data are mixed more naturally on the pixel 6.

 That is, according to the sub-pixel arrangement in FIGS. 4 (c) and 4 (d), a natural third white gradation is expressed by reducing color mixing unevenness between the first white gradation and the second white gradation. can do. Even when subpixels are arranged as shown in Figs. 4 (c) and 4 (d), the arrangement order of R, G, and B subpixels can be set arbitrarily.

 Next, a mechanism for displaying an image on the liquid crystal panel 5 will be described based on FIGS. 5, 6A and 6B, and Tables 3 and 4. FIG. First, for comparison with the present invention, a mechanism in which a conventional liquid crystal module displays an image will be described with reference to FIG.

 FIG. 5 is a block diagram showing a schematic configuration of a conventional liquid crystal module 7 that displays an image in four colors of G, B, and W. As shown in the figure, an RGB-RGBW converter 8 is connected to the liquid crystal module 7. The RGB-RGBW change ^^ 8 converts the input RGB color data into RGB W color data and outputs it to the timing controller 9. The timing controller 9 controls the display drive of the liquid crystal panel 10 based on the input RGBW color data. In other words, LCD module 7 accepts input of RGB color data, determines RGBW color data based on RGB color data, and displays an image based on RGBW color data.

On the other hand, as shown in FIG. 1, the liquid crystal display device 1 of the present embodiment has a gradation level-RGBW. Transform 2 is provided. Tone Level-RGBW Transform 2 outputs RGBW color data corresponding to the tone level to the LCD module 3 in order to represent the input tone level. That is, the liquid crystal module 3 according to the present embodiment accepts gradation level input, determines RGBW color data based on the input gradation level, and displays an image based on RGBW color data! . The input gradation levels are 511 gradations from 0 to 510 as shown in Table 3.

[0041] [Table 3]

A mechanism capable of increasing the gradation level from 256 gradations to 511 gradations will be described with reference to Table 3. Table 3 is a table showing an example of the conversion process performed in the gradation level-RGBW conversion 2.

 [0043] The first column from the left of the table shows the gradation level input to the gradation level-RGBW variable ^ 2. As shown in the table, the input gradation level can take a value from 0 to 510. Gradation level-When the gradation level is input to RGBW change ^ 2, the output (R, G, B) and output (W) corresponding to the input value of gradation level are determined. The output (R, G, B) is the first white gradation created using the color data for each RGB color, and the output (W) is created using the W color data. The second white gradation.

 Note that when the first white gradation is generated using RGB color data, the output values of the RGB color data are equal to each other. For example, when (R, G, B) = 1, R = G = B = 1.

[0045] The second column of the left force in the table shows the output (R, G, B), that is, the first white gradation. As shown in the table, the first white gradation can take 256 gradation values from 0 to 255. [0046] The third column from the left of the table shows the output (W), that is, the second white gradation. As shown in the table, the second white gradation can take 256 gradation values from 0 to 255.

 [0047] Finally, the rightmost column of the table shows the white gradation, that is, the third white gradation created by the combination of output (R, G, B) and output (W). As shown in the table, the 3rd white gradation is expressed as an average of the 1st white gradation and the 2nd white gradation, so it is possible to express more detailed and powerful gradations. It has become.

 [0048] For example, in the conventional example of Table 2, by setting RGBW color data to R = G = B = W = 1, a gradation of 1 is expressed, and R = G = B = W = 2 This expresses a gradation of 2. On the other hand, in the gradation level-RGBW variation 2, by setting R = G = B = 1 and W = 2, the gradation of 1.5 can be expressed as shown in Table 3. That is, in the liquid crystal display device 1, the first white gradation created using the RGB color data and the second white gradation created using the W color data are averaged, that is, the third white gradation. Since it is visible, the number of white gradations will be expanded.

 FIG. 6A is a plan view showing a state where the first white gradation and the second white gradation are displayed in the pixel 6. In the figure, the shaded portion indicates that the gradation value is smaller than the portion not shaded, that is, 喑.

 [0050] In FIG. 6 (a), when the 1S pixel 6 in which the boundary between the bright part and the dark part is clearly visible in the pixel 6 is arranged on the liquid crystal panel 5 and viewed from a distance from the liquid crystal panel 5, The dark part and the dark part are averaged and visually recognized as intermediate brightness. For example, if the input gradation level is 3 in Table 3, the first white gradation is 1 and the second white gradation is 2. The white gradation perceived at this time is 1.5, which is an average of 1 and 2.

[0051] When the first white gradation and the second white gradation are combined and there is a large difference between the two gradations, the gradation difference between the two is visually recognized as a striped pattern on the liquid crystal panel 5. There are things. As a result of trial and error, the inventors of the present application have confirmed that the above striped pattern is not visually recognized if the gradation difference between the first white gradation and the second white gradation is within 1% of the maximum gradation. discovered. Therefore, the gradation difference between the two is preferably within 1% of the maximum gradation. In the present embodiment, since the maximum is 256 gradations, the difference between the two is 1% of 256. 2. Within 56, that is, if the difference is 2 gradations or 1 gradation, the striped pattern is not visually recognized. Display a good image be able to. In the present embodiment, an example is shown in which the difference between the first white gradation and the second white gradation is one gradation.

 [0052] As described above, the pixel 6 alone can express the third white gradation in which the first white gradation and the second white gradation are combined. Thus, the third white gradation can be expressed by combining the first white gradation and the second white gradation.

 FIG. 6B is a plan view showing a state in which the first white gradation and the second white gradation are displayed on the liquid crystal panel 5. As shown in the figure, pixels 6 are arranged on the liquid crystal panel 5, and a first white gradation and a second white gradation are displayed in each pixel. In FIG. 6 (b), as in FIG. 6 (a), the shaded portion indicates that the gradation value is smaller than the portion not shaded, that is, darker.

 In FIG. 6B, the light-dark relationship between RGB and W, that is, the first white gradation and the second, in the odd and even rows of the pixels 6 arranged in the liquid crystal panel 5. The light / dark relationship with the white gradation is reversed. As shown in the figure, the light and dark become a checkered pattern by reversing the light and dark relationship in adjacent rows. By displaying the checkerboard pattern, the color mixture of the first white gradation and the second white gradation can be made more natural.

 [0055] Table 4 shows an example of conversion processing performed by the gradation level-RGBW converter 2 when the light-dark relationship is reversed. As shown in Table 4, the gradation of (R, G, B), that is, the first white gradation, and the gradation of (W), that is, the second white gradation, are (first white gradation) ≥ (2nd white gradation), that is, the 1st white gradation is combined to become brighter. On the other hand, in Table 3, (first white gradation) ≤ (second white gradation), that is, the second white gradation is combined so that it is brighter. Therefore, for example, by applying the combinations shown in Table 3 to odd rows and applying the combinations shown in Table 4 to even rows, it is possible to display a light and dark checkered pattern as shown in Fig. 6 (b). Monkey.

 [0056] In addition, since the technology of displaying the checkerboard pattern by inverting the light-dark relationship for each pixel in the adjacent row is well known, this technology is applied to the sub-pixel (R, G, B) and the sub-pixel (W ), It is possible to reverse the light-dark relationship between the first white gradation and the second white gradation in adjacent rows.

[0057] [Table 4] Feel to eyes

 Input gradation level Output (R, G, B) Output (W) White gradation

 0 0 0 0

 1 1 0 0.5

 2 1 1 1

 3 2 1 1.5

 4 2 2 2

510 255 255 255

It should be noted that the method of combining the first white gradation and the second white gradation on the liquid crystal panel 5 is not limited to the combination of the above pine pattern. For example, even if the light-dark relationship is not reversed in the adjacent row, it is visually recognized as a third white gradation in which the first white gradation and the second white gradation are combined. That is, any arrangement is possible as long as the first white gradation and the second white gradation are mixed and visually recognized as the third white gradation.

 Next, details of the processing performed by the gradation level-RGBW converter 2 will be described with reference to FIG. 7 and FIG.

 FIG. 7 is a block diagram showing a main configuration of the gradation level / RGBW converter 2. As shown in the figure, the gradation level-RGBW transformation 2 includes the first white gradation creating unit 11 (first gradation creating unit), the second white gradation creating unit 12 (second gradation creating unit), and It has.

 [0061] The first white gradation generation unit 11 and the second white gradation generation unit 12 are configured so that the first white gradation and the second white gradation generation unit 12 represent the 511-step input gradation levels from 0 to 510. White gradations are created respectively.

 That is, when the gradation level of 511 levels is input to the gradation level-RGBW variation 2, the first white gradation creating unit 11 calculates the first white gradation based on the input gradation level. The created first white gradation is output to the timing controller 4. Further, the second white gradation creating unit 12 creates a second white gradation based on the input gradation level, and outputs the created second white gradation to the timing controller 4.

[0063] For example, in Table 4, when the input gradation level is 3, the first white gradation creating unit 11 uses the first white gradation whose gradation is 2 based on the input gradation level 3 Is set to 2 and The second white gradation creating unit 12 sets the output of the second white gradation to 1 based on the input gradation level 3. The first white gradation 2 and the second white gradation 1 created in this way are output to the pixel 6 via the timing controller 4 and assembled on the pixel 6 or the liquid crystal panel 5. It is visually recognized as a gradation of 1.5 where both are averaged together.

 FIG. 8 is a flowchart showing the flow of processing in the gradation level-RGBW converter 2. As shown in the figure, the first white gradation creating unit 11 and the second white gradation creating unit 12 confirm the presence / absence of a gradation level input (Sl). When there is an input signal, the first white gradation creating unit 11 creates a first white gradation based on the input gradation level and outputs it to the timing controller 4 (S2). At the same time, the second white gradation creating unit 12 creates a second white gradation based on the input gradation level and outputs it to the timing controller 4 (S3). After the output to the timing controller 4 is completed, return to S1 again to check whether the gradation level is input. If the gradation level input is not detected in S1, return to S1 again and check whether the gradation level is input.

 FIG. 9 is a circuit diagram showing a schematic configuration of the gradation level / RGBW conversion circuit 13 in which the gradation level / RGBW converter 2 is realized by hardware. As shown in the figure, the gradation level-RGBW conversion circuit 13 includes a first white gradation generation unit (first gradation generation unit) 14, a second white gradation generation unit (second gradation generation unit) 15, and It has.

 [0066] The first white gradation generation unit 14 receives the input of the gradation level and outputs color data for each of the RGB colors, and the second white gradation generation unit 15 receives the input of the gradation level. Accepts W color and outputs the previous color data.

In the figure, D0 to D8 indicate input gradation levels. D0 to D8 represent gradation levels in binary numbers, and D0 to D8 are assigned in order from the least significant digit. W0 to W7 represent the color data for the W color, and R0 to R7 represent the R color data of the RGB color data. W0 to W7 and R0 to R7, like the gradation level, represent the gradation value in binary number, and the lower digits are sequentially W0 to W7 and R0 to R7. Although not shown in the figure, G0 to G7 and BO, which are G and B color data: B7! /, Even from R0 to R7, from the first white gradation creating unit 14 Is output. The output values of G0 to G7 and B0 to B7 are the same values as RO to R7. As shown in the figure, the first white gradation creating unit 14 outputs values from Dl to D8 among the input gradation levels D0 to D8 as R0 to R7, respectively. On the other hand, as shown in the figure, the second white gradation creating unit 15 receives inputs of input gradation levels D0 to D8 and adds 1 to this number. Then, the number obtained by truncating the last digit after adding 1 is output as W 0 to W 7 in order from the lower digit.

 [0069] For example, specifically, when the input gradation level D is 2, since 2 is 10 (2) in binary notation, D0 to D8 are 000000010 (2). Here, (2) is added to the end of binary numbers to distinguish binary numbers from decimal numbers. The first white gradation creating unit 14 accepts inputs D1 to D8 out of the values D0 to D8 and outputs them as R0 to R7, respectively. That is, R0 to R7 are output as 00000001 (2). Similarly, 00000001 (2) is output to G0 to G7 and B0 to B7. On the other hand, the second white gradation creating unit 15 adds 00000010 (2) 〖1 of the input value to obtain 000000011 (2), and truncates the least significant digit of this number. Therefore, 00000001 (2) force S is output to W0 to W7. In other words, if the input level D is 2, the color data for R, G, and B will each be 1, and the color data for W color will also be 1.

 Note that the gradation level-RGBW conversion circuit 13 shown in FIG. 9 is an example of the gradation level-RGBW variation 2 of the present invention, and the configuration of the gradation level-RGBW variation 2 is not limited to this. Yes. Tone level-RGBW change ^^ 2 accepts the input of the tone level, and the color data for each RGB color and the color for W color in a combination that the tone difference between RGB and W is within 1% Any device that outputs data can be used. For example, a storage unit is provided in the gradation level-RGB W converter, and a table in which the input gradation, color data for each RGB color, and color data for W color are stored in the storage unit is stored. Alternatively, the output gradation can be determined according to the correspondence table.

 [Embodiment 2]

The following will describe another embodiment of the present invention with reference to FIGS. 10 and 11. FIG. Configurations other than those described in the present embodiment are the same as those in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiment 1 are given the same reference numerals, and explanation thereof is omitted. [0072] The liquid crystal display device of this embodiment can display more abundant white gradation by changing the area ratio of the sub-pixels.

 In the pixel 6 included in the liquid crystal display device 1 shown in Embodiment 1, the subpixels R, G, B, and W each occupy the same area. That is, each subpixel occupies 1Z4 of the area of the pixel 6. In this case, the first white gradation and the second white gradation are substantially equal when the gradation values are equal.

 [0074] For example, the first white gradation displayed with RGB color data R = G = B = 1 and the second white gradation displayed with W color data W = l are almost the same. The gradation is equal. This is because the light transmittance in each of the R, G, and B subpixels is about 1Z3, and the light transmittance in the W subpixel is about 1.

 That is, the amount of light passing through the R, G, and B subpixels is reduced to about 1Z3 by the color filter, while the amount of light does not change substantially in the W subpixel.

 Here, the area ratio of the R, G, and B subpixels to the W subpixel is (R, G, B): (W) = 3: 1. Therefore, when the RGBW color data is set equal, the ratio of the amount of light that passes through the R, G, and B subpixels to the amount of light that passes through the W subpixel is (R, G, B) : (W) = 3 X 1/3: 1 X 1 = 1: 1 It can be seen that the light intensity of both is almost equal, that is, the expressed white gradation is almost equal.

 [0077] In the above case, if the sum of the gradation values of the first white gradation and the second white gradation is equal, the display is performed regardless of the magnitude relationship between the first white gradation and the second white gradation. Tones are equal. For example, even if a first white gradation with a gradation value of 1 and a second white gradation with a gradation value of 2 are combined, the first white gradation with a gradation value of 2 Even when combined with the 1st second white gradation, the displayed gradation is almost the same.

 [0078] On the other hand, when the area ratio of the subpixel RGB and the subpixel W in each pixel is changed, a richer white gradation can be displayed. In this case, the range of white gradation that can be expressed is different between the first white gradation created by subpixel RGB and the second white gradation created by subpixel W.

[0079] Therefore, even when the sum of the gradation values of the first white gradation and the second white gradation is equal, if the first white gradation and the second white gradation are in a magnitude relationship, 1 White gradation and 2nd white floor The displayed gradation varies depending on the combination of the tones. For example, when a first white gradation with a gradation value of 1 and a second white gradation with a gradation value of 2 are combined, a first white gradation with a gradation value of 2 and a gradation value of 1 The displayed gradation differs from the combination with the second white gradation.

 FIG. 10 is a plan view showing a schematic configuration of the pixel 16 when the area ratio of the sub-pixels is R: G: B: W = l: l: l: lZ2. The pixel 16 has the same configuration as the pixel 6 described above except that the area ratios of the R, G, and B subpixels are different from those of the W subpixel.

 [0081] Since the area ratio of the sub-pixels is R: G: B: W = l: l: l: lZ2, the light quantity that passes through the R, G, and B sub-pixels and the W sub-pixel passes through. The ratio to the amount of light to be emitted is (R, G, B): (W) = 3X1 / 3: 1 / 2X1 = 2: 1. Therefore, when the first white gradation and the second white gradation have the same gradation value, the displayed gradation is (first white gradation) = (second white gradation) X 2 Become. Table 5 shows an example of the combination of (R, G, B) and (W) at this time, that is, the combination of the first white gradation and the second white gradation.

 [0082] [Table 5]

As shown in the table, the input gradation level is extended to 766 gradations from 765 to 765. This is because the combination pattern of the first white gradation and the second white gradation has increased when the first white gradation and the second white gradation have a magnitude relationship.

[0084] For example, in Table 5, when the first white gradation is 1 and the second white gradation is 2, the input gradation level is 4, the first white gradation is 2, and the second white gradation is 2. In case of gradation power, input gradation level Is 5. On the other hand, in the liquid crystal display device 1 of the first embodiment, as shown in Table 3 and Table 4, when the first white gradation is 1 and the second white gradation is 2, Even when the first white gradation power ^ and the second white gradation is 1, the input gradation level was 3, and the gradation levels of both were the same. That is, the combination pattern increases when the sum of the first white gradation and the second white gradation is equal and the first white gradation and the second white gradation are in a magnitude relationship.

 Therefore, when the pixel 16 having a configuration in which the area of the W subpixel is smaller than that of the R, G, and B subpixels, the R, G, B, and W subpixels all have the same area. Compared to the case, a richer gradation expression can be realized. In this case, the area of the R, G, and B subpixels increases, so the R, G, B, and B subpixels have the same color density compared to the R, G, B, and W subpixels. Becomes higher.

 Next, a case where the area ratio of RGBW sub-pixels is 1: 1: 1: 2 in each pixel will be described with reference to FIG. 11 and Table 6. FIG. 11 is a plan view showing a schematic configuration of the pixel 17 when the area ratio of the sub-pixels is R: G: B: W = 1: 1: 1: 2. The pixel 17 has the same configuration as the pixel 6 described above except that the area ratio of the R, G, and B subpixels is different from that of the W subpixel.

 [0087] Since the area ratio of the sub-pixels is R: G: B: W = 1: 1: 1: 2, the amount of light that passes through the R, G, and B sub-pixels and the sub-pixel of W pass through The ratio to the amount of light is (R, G, B): (W) = 3X 1/3: 2X1 = 1: 2. Therefore, when the first white gradation and the second white gradation have the same gradation value, the displayed gradation is (first white gradation) X 2 = (second white gradation). Table 6 shows an example of a combination of (R, G, B) and (W) at this time, that is, a combination of the first white gradation and the second white gradation.

[0088] [Table 6] 'Input gradation level Output (R, G, B) Output (W)

 0 0 0

 1 1 0

 2 0 1

 3 1 1

 4 2 1

 5 1 2

 6 2 2

 7 3 2

765 255 255

As shown in the table, the input gradation level is extended to 766 gradations from 765 to 765. This is because the first white gradation and the second white gradation are large and small, as in the case where the area ratio of the sub-pixels is R: G: B: W = 1: 1: 1: 1Z2. This is because the combination pattern of the first white gradation and the second white gradation has increased.

 [0090] That is, even when a pixel having a larger area of the W subpixel than the R, G, and B subpixels is used, the R, G, B, and W subpixels all have the same area. Compared to, a richer gradation expression can be realized. In this case, since the area of the W sub-pixel increases, the light transmittance of the entire pixel increases and a bright image can be displayed.

 In the present embodiment, when the area ratio of sub-pixels is R: G: B: W = l: l: l: lZ2 and R: G: B: W = 1: 1: 1 : Force explaining the case of 2 The area ratio of sub-pixels is not limited to these. That is, the present invention is not limited to the above example, but by changing the area ratio of the sub-pixels so that a difference occurs between the gradation that can be expressed by the first white gradation and the gradation that can be expressed by the second white gradation. Since the combination pattern of the first white gradation and the second white gradation can be increased, a richer white gradation can be expressed.

 [Modification]

In the above description, a rich white gradation is realized by combining the first white gradation expressed by the R, G, and B subpixels and the second white gradation expressed by the W subpixel. An example of this is shown. Here, R, G, B sub-pixels, C (cyan), M (magenta), Y (yellow) sub-pixels An example of realizing rich gradation expression by combining pixels will be described.

 [0093] (Combination of RGB and C)

 First, C color can be expressed by combining G color and B color. Therefore, it is expressed by the combination of the G color and the B color, as in the case of combining the white gradation expressed by the subpixels R, G, and B and the white gradation expressed by the subpixel W. The third cyan gradation can be expressed by combining the first cyan gradation and the second cyan gradation expressed by C color alone.

 Therefore, for example, the pixel 6 is composed of four sub-pixels as described in FIG. 3 and FIGS. 4A to 4D, and each of the sub-pixels has R color, G color, and B color. When C color is assigned, abundant cyan gradations can be expressed. Note that the color mixture of the first cyan gradation and the second cyan gradation can be executed by gradation level-RGBW transformation 2 as in the case where the pixel 6 has sub-pixels R, G, B, and W. it can.

 [0095] (Combination of RGB and M)

 Similarly, M color can be expressed by combining R color and B color. Therefore, the third magenta gradation is expressed by combining the first magenta gradation expressed by the combination of the R color and the B color and the second magenta gradation expressed by the M color alone. Can do.

 That is, by forming the pixel 6 including the R, B, and G subpixels and the M subpixel, a rich magenta gradation can be expressed.

[0097] (Combination of RGB and Y)

 Similarly, Y color can be expressed by combining R color and G color. Therefore, the third yellow gradation can be expressed by combining the first yellow gradation expressed by the combination of the R color and the G color and the second yellow gradation expressed by the Y color alone.

That is, by forming the pixel 6 including the R, B, and G subpixels and the Y subpixel, it is possible to express a large number of yellow gradations.

[0099] (Combination of RGB and CM)

As described above, the first cyan gradation and C color expressed by the combination of G color and B color The third cyan gradation can be expressed by combining it with the second cyan gradation expressed independently. The third magenta gradation can be expressed by combining the first magenta gradation expressed by the combination of the R color and the B color with the second magenta gradation expressed by the M color alone. .

[0100] In other words, by forming the pixel 6 including the R, B, and G subpixels and the C and M subpixels, a rich cyan gradation can be expressed, Abundant magenta gradation can be expressed.

[0101] (Combination of RGB and CY)

 Similarly, by forming pixel 6 with R, B, and G subpixels, and C and Y subpixels, a rich cyan gradation can be expressed and abundant. It is possible to express the yellow gradation.

[0102] (Combination of RGB and MY)

 Similarly, by forming a pixel 6 having R, B, and G subpixels and M and Y subpixels, a rich magenta gradation can be expressed. Abundant yellow gradation can be expressed.

 [0103] (Combination of RGB and CMY)

 Here, when pixel 6 having R, B, and G sub-pixels and C, M, and Y sub-pixels is formed, cyan is obtained by combining G, B, and C colors. With the combination of R, B and M colors, magenta can be expressed with a combination of R, G and Y colors. Abundant gradation expression is possible.

 [0104] Furthermore, when the pixel 6 has R, B, G, C, M, and Y subpixels, it is represented by a mixed color of R, B, and G colors. It is possible to combine a white gradation and a white gradation expressed by a mixture of C, M, and Y colors. As a result, a rich gradation expression is possible even for white.

[0105] In addition to the subpixels R, G, B, C, M, and Y, a pixel further including the subpixel W may be used. In this case, the white gradation expressed by the subpixels R, G, and B, the white gradation expressed by the subpixels C, M, and Y and the white gradation expressed by the subpixel W are combined. Can Therefore, a richer white gradation expression is possible.

Note that the arrangement order of the subpixels R, G, B, C, M, and Y and the arrangement of the subpixels in the modification are not particularly limited, and can be set in any order and in any arrangement.

[0107] The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

[0108] Finally, each block of the liquid crystal display device 1, in particular, the RGB-RGBW converter 2 may be configured by a hard logic, or realized by software using a CPU as follows.

 That is, the liquid crystal display device 1 includes a CPU (.central processing unit) that executes instructions of a control program that realizes each function, a ROM (read only memory) that stores the program, and a RAM (random access that expands the program). memory), a storage device (recording medium) such as a memory for storing the above program and various data, etc. The object of the present invention is to provide a control program for the liquid crystal display device 1 which is software for realizing the functions described above. A recording medium on which the program code of the program (executable program, intermediate code program, source program) is recorded so as to be readable by a computer is supplied to the liquid crystal display device 1, and the computer (or CPU or MPU) is recorded on the recording medium. It can also be achieved by reading and executing the recorded program code.

 [0110] The recording medium includes, for example, a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy disk Z hard disk, and an optical disk such as CD-ROMZMOZ MD / DVD / CD-R. Disk systems, IC cards (including memory cards) Z optical cards and other card systems, or mask ROMZEPROMZEEPROMZ flash ROM and other semiconductor memory systems can be used.

[0111] Further, the liquid crystal display device 1 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network. Satellite communication networks can be used. Also, transmission media constituting the communication network For example, IEEE1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc. are wired, such as IrDA, remote control infrared, Bluetooth (registered trademark), 802.11 wireless , HDR, mobile phone network, satellite link, terrestrial digital network, etc. can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave, in which the program code is embodied by electronic transmission.

 [0112] Also, in the image display device according to the present invention, a first white gradation creating means for creating the first white gradation, a second white gradation creating means for creating the second white gradation, It is preferable that the image processing apparatus further includes third white gradation creating means for creating the third white gradation.

 According to the above configuration, the first white gradation creating means creates the first white gradation, and the second white gradation creating means creates the second white gradation. Then, a third white gradation creating means combines the first white gradation and the second white gradation to create a third white gradation, and the input gradation of the display device is used as the third white gradation. Since the level is expressed, it is possible to expand the number of white gradations!

 [0114] Further, in the image display device according to the present invention, when the first white gradation and the second white gradation are combined, the gradation difference between the two is within 1% of the maximum gradation. preferable.

 [0115] If the difference in gradation between the two is within 1% of the maximum gradation, the difference between the first white gradation and the second white gradation is difficult to be visually recognized as a striped pattern on the display screen.

 Then, in the image display device according to the present invention, in the pixels arranged in the matrix, the light / dark relationship between the first white gradation and the second white gradation in the m-th row, and m + 1 It is preferable that the light-dark relationship between the first white gradation and the second white gradation in the line is reversed.

 [0117] The contrast between the first white gradation and the second white gradation in the pixels of the adjacent column is inverted, so that the light and dark becomes a checkered pattern, and the first white gradation and the second white gradation are obtained. The color mixture with the tone becomes more natural.

 [0118] Further, in the image display device according to the present invention, in each of the pixels, R, G, B, and

The area ratio of W sub-pixels may be 1: 1: 1: n (n ≠ 1)! /.

[0119] By changing the area ratio of the sub-pixels, the gradation that the first white gradation can represent and the second white gradation There is a difference between the tone that can be expressed by the tone. Therefore, the number of combinations of the first white gradation and the second white gradation increases, and a richer white gradation can be expressed.

 [0120] The area ratio of R, G, B, and W subpixels may be 1: 1: 1: 2. In this case, since the area ratio occupied by the W sub-pixel is increased in each of the pixels, the light transmittance of the entire pixel is increased. Therefore, the number of white gradations can be expanded and the display on the image display device can be made brighter.

 On the other hand, the area ratio of R, G, B, and W sub-pixels may be 1: 1: 1: 1Z2. In this case, since the area ratio occupied by the RGB sub-pixels in each of the pixels is increased, the color density of the entire pixel is increased. Accordingly, the number of white gradations can be expanded, and the display in the image display device can have a higher color density.

 [0122] Further, it is possible to cause the computer to execute each of the above processes by a driving program for executing the driving method of the image display device.

 [0123] Further, the drive program can be operated on an arbitrary computer by recording the drive program on a computer-readable recording medium.

 Industrial applicability

[0124] The image display device of the present invention uses RGB color data and W color data to expand the number of white gradations, and therefore uses four RGBW subpixels. It is particularly suitable for liquid crystal televisions, mobile phones and the like.

Claims

The scope of the claims  [1] An image display in which a plurality of pixels having sub-pixel power are arranged in a matrix, and an image is displayed by changing the gradation of each sub-pixel according to the color data of each sub-pixel. A device,  The sub-pixel includes an RGB color sub-pixel and a sub-pixel of a color to be expanded in gradations expressed using color data of at least two colors selected from the RGB colors.  The first gradation is created using color data of at least two colors selected from among RGB colors, and the second gradation is created using the color data in the sub-pixels of the gradation number expansion target color,  An image display device characterized in that a third gradation is created by combining the first gradation and the second gradation, and an input gradation level of the image display device is expressed by the third gradation. . [2] The sub-pixel of the gradation target color is a W-color sub-pixel,  Create the first white gradation using the color data for each RGB color, The image display device according to claim 1, wherein the second white gradation is created using color data of the W color. [3] First gradation creating means for creating the first gradation, second gradation creating means for creating the second gradation, and third gradation creating means for creating the third gradation The image display device according to claim 1, further comprising: [4] The image according to claim 2, wherein, when the first white gradation and the second white gradation are combined, the gradation difference between the two is within 1% of the maximum gradation. Display device. [5] In the pixels arranged in a matrix, the light-dark relationship between the first white gradation and the second white gradation in the m-th row, and the first white gradation and the second whiteness in the (m + 1) -th row. 3. The image display device according to claim 2, wherein the brightness relationship with the white gradation is inverted (m is a natural number).  6. The image display according to claim 2, wherein in each of the pixels, the area ratio of R, G, B, and W subpixels is l: l: l: n (n ≠ l). apparatus. 7. The image display device according to claim 6, wherein n = 2. 8. The image display device according to claim 6, wherein n = 1Z2. [9] An image display in which a plurality of pixels having sub-pixel power are arranged in a matrix, and an image is displayed by changing the gradation of each sub-pixel according to color data for each sub-pixel. A method for driving an apparatus, comprising:  The sub-pixel includes an RGB sub-pixel and a sub-pixel of a target color whose number of gradations is to be expanded, which is expressed using color data of at least two colors selected from the RGB colors.  RGB color neutrality Processing to create the first gradation using at least two selected color data,  A process of creating the second gradation using the color data in the subpixel of the gradation number extension target color;  Processing to create a third gradation by combining the first gradation and the second gradation, and expressing the input gradation level of the image display device by the third gradation. A method for driving an image display apparatus. [10] A drive program for executing the method for driving an image display device according to claim 9, wherein the drive program causes a computer to execute the process. [11] A computer-readable recording medium on which the drive program according to claim 10 is recorded.