JP2002196709A - Transmission illumination type display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission illumination type display panel having a light controlling layer formed by printing by an ink jet print method which is capable of extremely easy control of the density or the like. SOLUTION: The transmission illumination type display panel has a light transmitting substrate 1 made of an acrylic resin, polycarbonate resin or the like, a light transmitting display layer 2 which is formed by gravure printing on at least one of the top surface of back surface of the substrate and which acts as a display part 21 by illumination from the back face of the substrate, a light shielding layer 3 which is formed by gravure printing or the like on the top surface or back surface of the substrate so as to shield the region except for the display part against light, and a light controlling layer 41 which is formed by ink jet printing method on the back face of the substrate at least in the part corresponding to the display part. The light controlling layer may be formed almost all over the back face of the substrate from the side where a light source 6 such as a cold cathode tube or the like is disposed to the other side, in particular, may be continuously formed almost all over the region where the display part is formed, or may be formed only in the region corresponding to the display part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transillumination type display panel. More specifically, the present invention relates to a transmissive illumination type display panel having a dimming layer formed by a simpler process than a conventional printing method. The transilluminated display panel of the present invention is used for home appliances, office automation-related equipment, vehicle instruments, inspection equipment in the industrial and medical fields, as well as sports equipment such as mobile phones and fishing equipment. It can be used as a display panel, such as a liquid crystal display, in which characters, pictures, and the like are visually recognized by transmitted light emitted from the back surface instead of self-emission.

[0002]

2. Description of the Related Art Hitherto, display panels in which characters, pictures, and the like are visually recognized by transmitted light from the back surface of liquid crystal display panels, illuminated display panels, and the like have been used in many product fields. In order to achieve uniform illuminance over the entire display surface of such a display panel, as shown in FIG. 3, a light source is disposed at a position far away from the back surface of the display surface and at a position corresponding to the center of the display surface. Need to be placed.

However, in recent years, products have been miniaturized irrespective of the product field, and it has been difficult to maintain a sufficient distance between the back surface of the display surface and the light source. It's not easy. If a certain amount of space can be secured on the back surface of the display surface, printing can be performed on the back surface of the display surface to form a dimming layer, and the illuminance can be adjusted. However, the base material that forms the display surface is often made of plastic, requires advanced techniques such as screen printing and tampo printing, and can often be handled only by expensive printing methods. .

[0004] The screen printing method is the most frequently used printing method, and can follow slight irregularities and deformation of the base material. However, this printing method is basically for the primary and secondary surfaces, and cannot perform precise printing on the tertiary surface. On the other hand, the tampo printing method can follow the deformation more than the screen printing method. However, since the pattern etc. is greatly deformed according to the degree of deformation, for example,
It can only print on a very small area of about several square centimeters. Further, it is difficult to transfer all of the ink transferred from the plate to the substrate, and it is not easy to keep the thickness of the print constant. Note that these printing methods are basically based on one-color, one-step printing. In order to obtain uniform illuminance on the entire display surface, three to three printing steps may be used in some cases.
As many as ten steps of printing are required, and the product cost is greatly increased according to the number of times of printing.

When almost no space can be secured on the back side of the display surface, a light source must be provided at one end of the display panel. In such a case, the side on which the light source is located is not provided. The display surface becomes bright and gradually darkens toward the other end, and the display surface cannot have uniform illuminance. For this reason, it is common to use a light guide plate called a light guide and adjust the light intensity as shown in FIG. However, since there is not enough space, the shape of the light guide is limited. Further, in order to uniformly control the light on the entire display surface, as shown in FIG. Printing for dimming must also be performed, which makes the process complicated and increases the product cost.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and requires advanced techniques such as screen printing and tampo printing. It is an object of the present invention to provide a transmissive illumination type display panel having a dimming layer formed by inexpensive inkjet printing in which the shape of printing and printing can be adjusted very easily.

[0007]

According to a first aspect of the present invention, there is provided a transmissive illumination type display panel which is formed on a translucent substrate and at least one of a front surface and a rear surface of the substrate, and is illuminated from a rear surface side of the substrate. A light-transmitting display layer serving as a display portion, a light-shielding layer formed on the front surface or the back surface of the substrate to block light except for the display portion, and at least corresponding to the display portion on the back surface side of the substrate. And a dimming layer formed on a portion thereof, wherein the dimming layer is formed by inkjet printing.

[0008] A transillumination type display panel according to a second aspect is formed on a translucent substrate and at least one of the front surface and the back surface of the substrate, and becomes a display section by illumination from the back surface side of the substrate. A light-transmitting display layer, a light-shielding layer formed on the front surface or the back surface of the substrate to shield a portion other than the display portion from light, and a light control layer, and the light control layer is provided at least on the display portion. A light guide disposed on the back side of the substrate so as to be located at a corresponding portion, wherein the dimming layer is formed by inkjet printing. And

In this transmissive illumination type display panel, in the daytime, the display portion is visually recognized by natural light by the color tone of the display layer, and the portion other than the display portion is visually recognized by the color tone of the light shielding layer, generally a black color tone. On the other hand, when a light source for illuminating from the back side is turned on at night or the like, there is an influence of incident light from the outside, etc., but the display section is clearly displayed by the transmitted light to the color tone of the display layer. Further, a display layer is formed on the front and back surfaces of the substrate as described below, and the display layer on the front surface is easily viewed with respect to black, for example, a white color, and a mixed color with white has a predetermined color tone on the back surface. By forming a display layer that
A transmissive illumination type display panel that is easily visible at all times when not lit or lit can be provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to an embodiment with reference to FIGS. FIG. 1 is a cross-sectional view schematically showing one example of a transmission illumination type display panel of the present invention in which a dimming layer is formed on the back surface of a substrate by inkjet printing. FIG. 2 is a cross-sectional view schematically showing another example of the transmissive illumination type display panel of the present invention in which a dimming layer is formed on the surface of the light guide facing the substrate by inkjet printing. The substrate 1 has excellent transparency,
Substrate made of acrylic resin, acrylonitrile-styrene-based resin, styrene-based resin, polycarbonate-based resin, etc., as long as it has sufficient mechanical strength and heat resistance and weather resistance, is not particularly limited. Can be used.

The display layer 2 can be formed by printing a translucent ink, and at least a part of the display layer 2 becomes the display section 21. The display layer has dimensions that will be the display part from the beginning,
It may be formed in a shape or the same shape as the display unit, and may be formed in a slightly larger size. Further, the display layer may be formed on substantially the entire front and back surfaces of the substrate.

As the ink, it is possible to use an ink in which a colorant which does not greatly impair the transparency of the display layer, such as a transparent pigment or dye, is mixed with an acrylic resin, a vinyl chloride resin or the like as a binder. . Printing can be performed by a general printing method such as gravure printing or screen printing. The display layer may be formed on the front surface or the back surface of the substrate, but when formed on the front surface, it is preferable to provide a protective layer made of a resin having excellent transparency such as an acrylic resin. With this protective layer, the initial color tone, gloss and the like of the display layer are maintained for a long time.

The display layer may be formed only on the front surface or the back surface of the substrate, or may be formed on both front and back surfaces. Further, each display layer formed on the front surface or the back surface may have the same color tone or different color tones. By forming display layers of different colors on the front and back surfaces, a display portion of a color tone of a specific mixed color, which is not easy with a single layer, can be formed.

The light-shielding layer 3 can be formed by printing a light-shielding ink, and is formed on a portion of the display layer other than a portion serving as a display portion. As the ink for forming the light-shielding layer, an ink in which a colorant having a sufficient hiding power such as carbon black or a black pigment or dye is blended with an acrylic resin or a vinyl chloride resin serving as a binder is used. can do. Printing can be performed by a general printing method such as gravure printing or screen printing. This light-shielding layer may be formed on the front surface or the back surface of the substrate, but when formed on the front surface, it is preferable to provide a protective layer made of a resin having excellent transparency such as an acrylic resin. This protective layer maintains the initial gloss and the like of the light-shielding layer for a long period of time.

The light control layer 41 formed by ink-jet printing corrects the difference in illuminance of the display unit due to the distance from the light source 6 such as a cold cathode tube, so that the entire illuminance of the display unit becomes uniform. For adjustment, it is formed on at least a portion corresponding to the display unit on the back surface of the substrate. Further, the dimming layer may be formed continuously over the entire rear surface of the substrate from one side of the light source to the other side. When the display layer and the light shielding layer are formed on the surface of the substrate, the light control layer can be directly formed on the back surface of the substrate, and at least one of the display layer and the light shielding layer is formed on the back surface of the substrate. If
It can be formed on the back surface of the substrate including those surfaces and the like.

The light control layer is formed on the surface of the light guide 5 facing the back surface of the substrate, and the light guide is disposed such that the light control layer is located at least on a portion corresponding to the display portion on the back surface of the substrate. Is done. The dimming layer may be formed continuously over the entire rear surface of the substrate from one side of the light source to the other side. As the light guide, a generally used light guide made of an acrylic resin, a polycarbonate resin or the like having excellent transparency can be used as it is. The light control layer may be formed from the upper surface of a fine uneven portion or the like provided for light control at a position corresponding to the display portion of the light guide, or may be a smooth surface without the uneven portion. It may be formed on a surface.

The dimming layer may be formed continuously from substantially one side of the light source to the other side over substantially the entire back surface of the substrate, particularly substantially over the entire region where the display section is formed. A light control layer slightly larger than the display unit may be formed in a portion corresponding to the display unit. Furthermore, the dimming layer may be continuous, partial, or may be formed by printing on the entire surface thereof, or may be printed and formed in a halftone dot shape. . The light control can be usually performed by shading from a dark color to a light color from one side of the light source to the other side, and a change in the color tone can be used together. Furthermore, when printing in the form of a halftone dot, the size of the halftone dot,
It is also possible to add light and shade according to the density of halftone dots and to control the light.

The light control layer is formed by ink-jet printing. In this inkjet printing, characters and pictures are formed by ejecting ink from pores provided in a nozzle head and attaching the ink to a printing surface such as a substrate as a number of dots having a diameter of about 50 to 70 μm. Is done. The number of dots is as large as 360 to 720 dots / inch, and even 1200 dots / inch, and the fineness of each dot is almost equivalent to that of normal offset printing and gravure printing.

The ink is sequentially ejected from the nozzle heads for the three primary colors and the complementary colors that move while being controlled by a computer, so that fine characters, pictures, and the like similar to photographs are formed. In addition, brightness, shading, and the like can be freely controlled by a computer, which is very suitable for printing for the purpose of dimming. Further, since printing can be performed in a non-contact manner, high-precision printing is possible and a light control layer having excellent light control performance can be formed as long as the surface to be printed is not very irregular.

The distance between the ejection port of the nozzle head and the surface to be printed, such as a substrate or light guide, is, for example, 5 to 2
If the length is as long as 0 mm, the outline of the periphery of the dot may be blurred. However, for the purpose of dimming, a blurred periphery is softer than a clear dot, which is rather convenient. Also, when it is necessary to make clear dots, all dots are made clear by a method such as moving the nozzle head up and down following the unevenness of the printing surface in combination with a vertical movement system such as a three-dimensional engraving machine. Can be something.

Ink-jet printing is more cost-effective than other conventional printing methods. In the conventional printing method, a printing plate is prepared and printed in a certain color using the printing plate, and then a different printing plate is prepared and printed in another color using the printing plate. It is customary to gradually produce the final product while repeating the printing of the color tone, and the cost is inevitably increased because complicated operations and steps are required.

Further, an automatic printing machine capable of simultaneously printing a large number of colors, such as about 4 to 5 colors, is provided and used. However, since it takes a long time to set printing conditions, the number of products is small. If you can not respond. In addition, in order to obtain a desired color tone, many prototypes are required, and costs such as design change, plate change, drawing with color change, plate making, and ink adjustment are added and accumulated.

According to the ink jet printing, not only the drawing but also the shading, the color tone and the like can be set in the print mode, and the initial cost generated can be greatly reduced. Further, since printing of all colors is completed by one-step printing, a large operating cost is not required. In addition, all can be processed by computer control, a uniform dimming layer can be easily formed, and there is an advantage that no skill is required to produce a transmission illumination display panel of excellent quality. .

[0024]

According to the first and second aspects of the present invention, the light control layer is formed by ink-jet printing, so that the shading, color tone, characters, and patterns of the print can be changed only by computer control. Can be performed, and an unprecedented color tone expression becomes possible. Further, unlike the conventional printing method, a printing plate is not required. Furthermore, there are many advantages such as the ability to easily form a dimming layer having a constant color tone, shading, etc. without requiring any skill in the printing technique.

In addition, by using ink-jet printing for dimming the transmissive illumination type display panel, a display surface having an arbitrary color tone can be easily obtained by a simpler method than ever. Furthermore, since the ink jet method is a non-contact printing method, the light control surface does not need to be smooth when light control is performed using a light guide. It can also be reduced.

[Brief description of the drawings]

FIG. 1 schematically shows an example of a transmission illumination type display panel of the present invention in which a distance between a display surface and a light source cannot be sufficiently set, and a dimming layer formed by inkjet printing is formed on the back surface of a substrate. It is sectional drawing.

FIG. 2 shows another example of the transmission illumination type display panel of the present invention in which the distance between the display surface and the light source cannot be sufficiently set, and a dimming layer formed by inkjet printing is formed on the surface facing the substrate of the light guide. FIG. 3 is a cross-sectional view schematically illustrating the example of FIG.

FIG. 3 is a cross-sectional view schematically illustrating an example of a transmissive illumination type display panel that can provide a sufficient distance between a display surface and a light source and does not particularly require dimming.

FIG. 4 is a cross-sectional view schematically showing an example of a transmissive illumination type display panel using a light guide in which a sufficient distance between a display surface and a light source cannot be obtained.

FIG. 5 is a cross-sectional view schematically showing an example of a transmission illumination type display panel in which a sufficient distance between a display surface and a light source cannot be secured and a light control layer formed by printing is provided.

FIG. 6 is a cross-sectional view schematically showing an example of a transmission illumination type display panel in which a distance between a display surface and a light source cannot be sufficiently set, a light guide is used, and a light control layer is provided by printing. is there.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Substrate 2, 2; Display layer, 21; Display part, 3;
1; a light control layer formed by inkjet printing; 42; a light control layer formed by a conventional printing method; 5;
Light guide, 51; fine irregularities, 6; light source, 7; outer frame.

Claims (2)

[Claims] 1. A light-transmitting substrate, a light-transmitting display layer formed on at least one of a front surface and a rear surface of the substrate, and serving as a display portion by illumination from a rear surface side of the substrate; Alternatively, a transmissive illumination type display including a light-shielding layer formed on the back surface for shielding a portion other than the display portion from light, and a dimming layer formed on at least a portion corresponding to the display portion on the back surface side of the substrate. A transmissive illumination type display panel, wherein the light control layer is formed by inkjet printing. 2. A light-transmitting substrate, a light-transmitting display layer formed on a front surface or a back surface of the substrate, and serving as a display portion by illumination from a back surface of the substrate; A light-shielding layer formed to shield a portion other than the display portion from light, and a light control layer, and the light control layer is disposed on the rear surface side of the substrate such that the light control layer is located at least in a portion corresponding to the display portion. A light guide to be provided, and a transmission illumination type display panel comprising:
A transillumination type display panel, wherein the dimming layer is formed by inkjet printing.