JPH0736400A - Display panel - Google Patents

Abstract

PURPOSE:To provide a transmission type display panel which can add the depth of color concentration expression territory, mesh point continuity, or the like to an image, offer fine variation of color by the angle of visibility on the observer side, and is high in the image quality, simple in manufacture, and low in the cost. CONSTITUTION:Rays radiated from a light source 30 are passed through mesh point image layers 24, 23, 22, 21, 14, 13, 12, 11, and the image of a display panel 10 is recognized by the passing rays. Because the mesh point image layers of same color are laminated so as to dislocate the mesh point positions, arrangement of the mesh points is in a continuous tone and smooth expression similar to a photograph is possible. Due to the mesh points of different color, colors are mixed by the passing rays, and hence an image of optional color tone can be constituted. A transparent layer 15 of decided thickness is provided between first image point layers and second image point layers, and hence the image of perspective feeling and depth can be realized. When the visualizing position is changed, in such a way as from the angle of visibility from 101 to 102, overlapping balance of the mesh points is changed so as to change the color of the image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internally illuminated transmissive display panel.

[0002]

2. Description of the Related Art In recent years, with the diversification of information and the trend toward fashion, a transmission type display panel having a light source on the back side of the display panel called an internally illuminated display panel (display) has become popular as an information tool. Conventionally, as a method for manufacturing this kind of display panel, there are four methods of yellow, magenta, cyan, and black by photo enlargement called color corton, screen printing or offset printing.
There is one in which colors are laminated in a halftone dot pattern and the colors are expressed by mixing the colors.

[0003]

However, each of the conventional methods for manufacturing the above-mentioned display panel has the following problems. Since the display panel using the color corton is based on the photographic principle, it basically reproduces the color tone of the positive image of the original faithfully, but if the enlargement ratio is large, the image will be rough, and it will be halftone synthesized by printing. On the other hand, it is difficult to control the color intensity and the tint.

In the manufacture of the display board by printing, the screen printing can express a dark color suitable for a transmission image, but it is difficult to reproduce fine halftone dots, and there is a problem that halftone dots are visible when viewed closely. Also, offset printing can form fine halftone dots, but since the ink thickness is thin, only light colors can be expressed,
The expression density range when the light of the backlight is transmitted becomes very narrow.

Therefore, it is generally considered to solve such a problem by overprinting an image on a sheet having one surface or a transparent surface. However, when this method is used, light interference fringes called moire may occur due to the regular overlapping of halftone dots.Therefore, a white sheet should be sandwiched between the dots during printing and halftone dots should be printed from both sides. There is a constraint that it must be. Although it is possible to manufacture a product that does not cause moire, the method of overprinting an image is not practical because the manufacturing yield is very poor. further,
Since the image composition is only a thin ink, there is little freedom in color mixing, the depth of the color as a transmission image is poor, and it is difficult to impart subtle color changes depending on the viewing angle.

As described above, there is no transmissive display panel which is capable of controlling the strength and weakness of colors and controlling the tint, and which has the degree of freedom of color mixing due to the backlight as a transmissive image and has an excellent appearance. It was The present invention has been made in order to solve such a problem, for example, while adding depth such as color density expression area and dot continuity to an image,
It is an object of the present invention to provide at low cost a transmissive display panel which has a high image quality and can be manufactured in a simple manner and which can be subtly changed in color depending on the viewing side viewing angle.

[0007]

A display board of the present invention for solving the above-mentioned problems is a display board for displaying a color image by laminating at least two or more colored halftone dot image layers. At least one color halftone dot image layer among the image layers has a plurality of halftone dot image layers in which the stacking positions within the same image representation area are changed at substantially equal angles.

[0008]

Embodiments of the present invention will be specifically described with reference to the drawings. A display panel according to an embodiment of the present invention is shown in FIGS. The display board 10 sandwiches the transparent layer 15 and corresponds to each color of black, cyan, magenta, and yellow.
1, 12, 13 and 14 are on the viewing side, and the halftone image layer 2
1, 22, 23 and 24 are laminated on the light source 30 side.

The halftone dot image layers 11 and 21, the halftone dot image layers 12 and 22, the halftone dot image layers 13 and 23, and the halftone dot image layers 14 and 24 of the same color have halftone dot angles of black: 75 ° and cyan: It is fixed at 15 °, magenta: 45 °, and yellow: 0 °, and the formation areas of the same image are the same. On the other hand, in the display effective range, the display effective range of the halftone dot image layer on the viewing side or the light source 30 side is shifted in at least one of the vertical and horizontal directions, and the image expression areas are aligned and stacked. As an example, the procedure for laminating the halftone dot image layer of magenta will be described below with reference to FIG.

FIG. 3A is a halftone dot image formed by using a negative mask of magenta obtained by color-separating a photographic original. FIG. 3B is a screen formed by using a negative mask in which the effective display range 50a of the screen image 50 shown in FIG. 3A is color-separated by shifting the plane coordinates of the trimming range while keeping the screen angle of 45 °. A point image 51 is shown. Therefore, the effective display range 50a in FIG. 3A is the effective display range 5 in FIG.
It corresponds to 1a. Then, as a result of shifting the plane coordinates, the display effective ranges 50a and 51a, which are originally the same image, are formed as halftone dots at different positions. As a result, when the effective display areas 50a and 51a are aligned and stacked, the effective display area 52a can be formed by a more continuous expression of halftone dots as shown in FIG.
However, in the case of only the same color, if the halftone dot images are directly laminated, the same effect as simply increasing the halftone dot ratio cannot be obtained, the desired effect cannot be obtained, and at the same time moire is likely to occur. It is preferable to form layers of different colors or transparent layers between the laminated layers to avoid direct contact. As for magenta, yellow, cyan, and black other than magenta can also be laminated by shifting the effective display range.

Next, the color density of the colored layer forming the halftone dots is
It cannot be limited because it is also affected by the amount of light transmitted through the light source 30, but when the color density is low, the region that can be expressed is narrowed when four colors are stacked, so that it is necessary to stack a large number of times. In this case, the thickness of the entire image increases, and it becomes difficult to align the halftone dot image layers during lamination. Therefore, when four-color halftone dot image layers are laminated, it is most preferable to make the halftone dot image layers into two layers in view of cost, man-hours, yield and the like. In order to realize sufficient density expression as a transmission image by using two layers, the color density of halftone dots of each color is preferably 0.5 or more, and more preferably 0.8 or more. The color density at this time was measured by inserting a complementary color filter for each color with a DM-500 transmission densitometer manufactured by Dainippon Screen.

When the thickness of the halftone dots is small, the pigment content is limited and it is difficult to impart the above-mentioned color density.
On the other hand, if the thickness is too thick, it prevents the color mixing of sufficient colors. From the above viewpoint, the thickness of the halftone dot is preferably 1 to 15 μm, more preferably 2 to 5 μm. For image formation by halftone dots, specifically, screen printing and Cromalin of Dupont Co. are widely used, but the sharpness of halftone dots, the uniformity of the halftone dot layer thickness, the ease of alignment, and From the viewpoint of ease of forming the transparent layer 15 and the like, the application of the color proofing method using a sheet material is more preferable than the printing using an ink.

The transparent layer 15 needs to have at least the thickness of the halftone dot image layer used so that the halftone dots of the same color are not recognized to be on the same plane. However, the transparent layer 1
If the thickness of 5 is too large, the clearance between the halftone dot image layers becomes too large and the outline of the image is not sharp.
Further, a problem occurs that sufficient color mixture of the first layer and the second layer due to transmitted light is hindered, and it becomes difficult to perform good color expression. Therefore, the upper limit of the thickness of the transparent layer 15 is the size of the entire image or the like. Since the display proper distance changes due to the above, the upper limit of visible stacking changes, but about 100 to 500 μm is preferable.

The transparent layer does not have to be a single layer, but may be divided or inserted in the vicinity of the halftone image layer to be multilayered or emphasized. Further, the transparent layer is effective as long as it is a transparent body, but it is better to form the transparent resin layer than the air layer in terms of light transmittance and alignment. When the light source 30 is not turned on, the image on the display panel 10 is recognized only by the reflection of the light rays incident from the viewer side. When the light source 30 is turned on, the light rays emitted from the light source 30 are reflected by the halftone dot image layers 24, 2.
3, 23, 21, 14, 13, 12, 11, and the image of the display board 10 is recognized by the passing light rays.

Since the halftone dots of the same color and the same expression area are laminated so that the halftone dot positions in plane coordinates are displaced, in the present embodiment, the four-color halftone dot image layers are laminated or the coordinates are not shifted. In comparison with the case where the halftone dot image layer is laminated twice, the halftone dot arrangement becomes continuous and a smooth expression similar to a photograph is possible. In addition, since halftone dots of different colors are mixed by the passing rays, it is possible to form an image with an arbitrary color tone. Further, the degree of color mixing can be adjusted by changing the size of halftone dots of each color to be laminated.

Further, since the transparent layer 15 having a predetermined thickness is provided between the halftone dot image layers of the first layer and the second layer, an image with a sense of perspective and a large depth can be realized. Further, as shown in FIG. 1, when the visually recognized position is changed, the tint of the image changes because the overlapping balance of the halftone dots changes between the viewing angle 101 and the viewing angle 102. For example, if the image viewed from the front is viewed at a 30 ° angle, magenta is strongly colored,
° Cyan can be strongly colored when viewed obliquely.

In order to effectively change the balance, it is necessary to appropriately change the color mixture balance of the halftone dots. However, in the image, dark portions, such as 100% cyan and 100% magenta, are included. Since is a solid surface rather than a point, it is difficult for the color mixing balance to change depending on the viewing angle. Therefore, when a document is color-separated by an electronic scanner, it is forcibly not to use an expression area having a halftone dot ratio of 100% for each color component. It is preferable to decompose the image with a maximum halftone dot ratio of about 95% or less and use it for image formation.

On the other hand, in the image, the portion represented by three colors of yellow, magenta and cyan is replaced with black.
It is also possible to change the hue balance by performing an Under Color Removal (hereinafter, referred to as UCR) process to reduce the relative ratio of the three components that control the hue. In this embodiment, the transparent layer 15 is inserted between the halftone dot image layers of the first layer and the second layer to realize the image depth. However, in the present invention, a certain sense of image depth can be obtained without inserting the transparent layer. It is possible.

As a method of forming the image layer, a method of laminating a lenticular lens on the image surface and incorporating various colors in the image according to the lens angle is also possible, but the manufacturing cost is high and the manufacturing method is complicated. Therefore, the same effect can be realized at a lower cost by the present invention. Hereinafter, an experiment was carried out by changing the configuration of the display board with respect to the color density, continuous length, and color change when the display board was visually recognized. The structure or manufacturing process of each example and comparative example will be described below.

Example 1 The transmission density of the photosensitive film forming each halftone image layer is
The yellow halftone image layers 11 and 21 are 0.9, the magenta halftone image layers 12 and 22 are 1.2, the cyan halftone image layers 13 and 23 are 1.4, and the black halftone image layers 14 and 24 is 1.4. The halftone dot thickness is about 4 μm, and a transparent image transfer layer of about 50 μm is provided on a 100 μm polyethylene terephthalate sheet as an image receiving sheet.

As an original for forming an image, a positive film is set to an effective display range output A2 size by a Luxscan electronic color scanner manufactured by Fuji Photo Film Co., Ltd., and the trimming range is shifted to produce a color under a standard condition of a dot density of 175 lines / inch. Disassemble and create two negative masks. After that, through a negative mask on a predetermined four-color photosensitive film, ultraviolet exposure,
Develops and transfers the image, and supports 4 types of masks. 4
A laminated image of color halftone dots is formed. Using 100 μm polyethylene terephthalate as a support, the effective display range of each image was aligned on both sides of the sheet having the heat-sealing layer and laminated to form a transmission type display panel.

Second Embodiment In the first embodiment, the color separation condition is set to an expression region having a halftone dot ratio of 0 to 90% to prevent halftone dots from becoming a solid surface, and one of the two negative masks is used. UCR is applied to the color separation. The other steps were the same as in Example 1, and a transmissive display panel was formed with UCR processed two types of images as the display side.

Comparative Example Using only the color separation negative mask shown in Example 1, two laminated images were formed under the same separation conditions, and then laminated on a transparent support as in Example 1 to form a transmissive display panel. Table 1 shows the experimental results of the display characteristics of the display panels of Examples 1 and 2 and Comparative Example.

[0024]

[Table 1] As is clear from the results of Table 1, it was found that stacking images under different decomposition conditions exhibited better effects in terms of continuous length and color change than stacking images under the same decomposition conditions. . Further, it has been found that the color separation condition is better when the color separation condition is set in the expression region having a halftone dot ratio of 0 to 90%.

[0025]

In the transmission type display panel of the present invention described above, by changing the stacking position of the halftone dot image layers of the same color in the same expression area, it is possible to realize a realistic image which has never been seen in the past, and a high quality image. Most suitable for display panel. Specifically, halftone dots can be expressed in a nearly continuous tone even though it is a halftone dot image using the printing principle, and the expression color can be subtly changed depending on the viewing angle by applying the color mixing principle.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of a display panel of the present invention.

FIG. 2 is an explanatory diagram showing a halftone dot angle of each color forming a halftone dot image of one embodiment on the display board of the present invention.

FIG. 3 is an explanatory diagram showing the overlapping of halftone dot images of one embodiment on the display panel of the present invention.

[Explanation of symbols]

 10 Display Panel 11, 12, 13, 14 Halftone Image Layer 15 Transparent Layer 21, 22, 23, 24 Halftone Image Layer 30 Light Source

Claims (1)

[Claims] 1. A display panel for displaying a color image by laminating at least two colors of colored halftone dot image layers, wherein at least one halftone dot image layer among the halftone dot image layers comprises:
A display panel having a plurality of halftone dot image layers in which the stacking positions within the same image representation area are changed at substantially equal angles.