JPH07101261B2 - Diffuse reflection means for edge light panel and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge light panel which is used as a liquid crystal backlight of a liquid crystal display device such as a computer, a word processor and a television receiver, or is widely used for various kinds of illumination such as a signboard, and its irregular reflection means is particularly preferable. And a manufacturing method thereof.

[0002]

2. Description of the Related Art Various types of diffuse reflection means for this kind of edge light panel have been proposed. Particularly, as shown in Japanese Patent Laid-Open No. 63-62104 provided by the present inventors, an equidistant matrix form is used. Most commonly used is a transparent substrate with a halftone dot pattern that is enlarged stepwise in the light source separation direction without changing the positional relationship. Edge light panels having diffuse reflection means are widely used for liquid crystal backlights and other illuminations because they satisfy both brightness and uniformity.

In recent years, however, particularly in liquid crystal backlights, the liquid crystal display surface tends to change from monochrome to color, and the illumination of the color liquid crystal display surface requires a significantly improved luminance as compared with the conventional one.

Therefore, the inventors of the present invention, for example, have filed Japanese Patent Application No.
No. 342113 has been proposed as a diffuse reflection means for improving the brightness, which is particularly suitable for a color liquid crystal display surface.

According to this proposal, the diffuse reflection means is a light-transmitting ink, and if necessary, fine beads for diffuse reflection mixed therein, and the top reflection layer of the ink surface formed integrally by thermal transfer and printing. It is supposed to have
It is supposed that the irregular reflection means can greatly improve the brightness.

[0006]

[Patent Document 1] Japanese Patent Application No. 3-342
The diffuse reflection means according to No. 113 is effective in achieving a desired high brightness, but on the other hand, it is necessary to further form a top reflection layer by thermal transfer or printing on the ink which is formed by printing and cured. Of productivity due to complication of
It means that there are problems such as increased costs.

The present invention has been made based on such a situation, and the problem to be solved by the present invention is the above-mentioned Japanese Patent Application No. 3-342.
The diffuse reflection means of the edge light panel which is preferably used for illuminating the color liquid crystal display surface in place of No. 113 and the diffuse reflection of the edge light panel which easily and surely forms this diffuse reflection means without complicating the process or work. Means to provide a manufacturing method.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a diffused reflection substrate formed of a light-transmitting ink is formed on a transparent substrate by printing, and a relative position is arranged on the transparent substrate side so as to form an intermediate diffused reflection layer on the diffused reflection substrate. An irregular diffuser means for an edge light panel, comprising transparent beads and a granular or powdery fine reflective substance arranged at a relative position on the irregular diffuser substrate so as to form a surface side reflective layer on the diffuse diffuser substrate surface side. (Claim 1), The diffused reflection means of an edge light panel (Claim 2), characterized in that the reflective substance of Claim 1 is used as a reflective bead encapsulating a reflective agent, and the reflective bead of Claim 2 is white. A diffused reflection means of an edge light panel (claim 3), characterized in that it is a white bead encapsulating a system pigment, and the reflective material of claim 1 is a white pigment. Printing process relating to irregular reflection means of an edge light panel (claim 4) and printing on a transparent substrate with a light-transmissive ink in which fine transparent beads having a difference in specific gravity and a fine reflective substance in a granular or powder form are added and mixed And a relative position division step of dividing relative positions so that the transparent beads are on the transparent substrate side and the reflective material is on the front surface side by the difference in specific gravity before the ink is cured after the printing step. A method for manufacturing a diffused reflection means of an edge light panel (claim 5), a method of manufacturing a diffused reflection means for an edge light panel (claim 6), wherein the relative position dividing step of claim 5 is a centrifugal separation step. The method for manufacturing the diffused reflection means of the edge light panel, characterized in that the relative position classification step is performed as a natural drying step with the ink slow-drying agent facing downward on the printing surface in a slow drying state (Claim 7)
These are the means of solving the above problems as the gist of the invention.

[0009]

In the diffused reflection means of the present invention, the incident light reaching the diffused reflection means is diffused by the fine transparent beads whose relative positions are arranged on the transparent substrate side so as to form an intermediate diffused reflection layer together with the diffused reflection substrate. On the other hand, the granular or powdery micro-reflecting substance arranged relative to the surface side so as to form the surface-side reflective layer sufficiently reflects the incident light reflected irregularly to the transparent substrate side and makes it incident on the irregular reflection substrate. It prevents the loss due to the emission of light and improves the brightness by utilizing the incident light as illumination light as much as possible.

In the method of manufacturing the diffuse reflection means of the present invention,
The difference in specific gravity acts in the uncured ink to distribute the relative positions of the transparent beads and the reflective material.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the drawings showing the following embodiments. In FIGS. 1 to 3, A is a liquid crystal backlight mounted in a liquid crystal display device, and the liquid crystal backlight A is From the liquid crystal display side of the liquid crystal display device, for example, a diffusing sheet 1 made of a milky white polyester film having a thickness of 75 μm 1, an edge light panel 10 and a bag-like reflecting sheet 2 having a C-shaped cross section made of a white polyester low-foaming film having a thickness of 188 μm, for example. On the other hand, the both end faces of the edge light panel 10 are laminated on each incident end face 1 while
2 and a pair of tube-shaped primary light sources 3 each made of a cold cathode tube are arranged on the incident end face 12.

The edge light panel 10 of this embodiment is, for example, a diffuse reflection means 20 formed on the back surface of an acrylic resin transparent substrate 11 having a thickness of 4 mm and a size of 130 mm × 160 mm.
Is provided so as to cover the entire surface.

The diffuse reflection means 20 has a halftone dot pattern in this example, that is, it is arranged in an equidistant matrix form and is separated from each incident end face 12 side of the transparent substrate 11 without changing its positional relationship. While the area ratios are gradually increased stepwise in the in-plane direction, the halftone dot pattern of the peak center position is used which maximizes the area ratio at the center positions farthest from the respective incident end faces 12. Diffuse reflection means 2 so that the entire surface has uniform brightness
It is assumed that the diffuse reflection amount of 0 is controlled.

The diffuse reflection means 20 formed as a set of halftone dots is formed by printing on the transparent substrate 11 by the screen printing method in this example. More specifically, the diffuse reflection means 20 is Diffuse reflection substrate 21 made of light-transmissive ink, fine transparent beads 22 arranged relative to this diffuse reflection substrate 21 on the transparent substrate 11 side so as to form an intermediate diffuse reflection layer, and relative to diffuse reflection substrate 21 so as to form a front side reflection layer. It is provided with a granular or powdery fine reflective material 23 arranged at the position on the surface side of the irregular reflection substrate 21.

In this example, the diffused reflection substrate 21 is made of a transparent medium (vehicle) as a main component, and is made into a minute protrusion by a light-transmissive printing ink to which a matting agent is added. Has elasticity and is well adapted to the above printing ink, and uses transparent acrylic hollow resin beads to prevent abnormal light emission due to damage of the diffused reflection substrate 21 due to impact, and the fine reflective material 2
Similarly, 3 is a reflection in which a transparent acrylic hollow resin bead 24 is similarly used as a foreskin, and titanium oxide, which is generally used as a white pigment of a reflective substance 25 having excellent reflectivity, is enclosed in the foreskin so as to obtain a white system. In this example, white granular beads are used.

The transparent beads 2 in this irregular reflection means 20
2, the reflective material 23, which is a white bead, has an average particle size of 8
The average particle size is 8 μm, the transparent beads 1.11 and the white beads 1.33, the average particle size is 22 μm, and the specific particle size is 1.14 μm to 22 μm (maximum diameter 20 μm to 50 μm). The relative positions of the transparent beads 22 and the reflective substance 23 in the irregular reflection substrate 21 are divided by this difference in specific gravity.

Explaining this further from the aspect of the method of manufacturing the diffuse reflection means 20, the manufacturing method is a light-transmitting ink in which the transparent beads 22 and the reflective material 23 of the white beads are added and mixed, that is, a medium (vehicle). Printing step of printing on the transparent substrate 11 so as to exhibit the above-mentioned halftone dot pattern, and the transparent beads 22 are on the transparent substrate 11 side and the reflective material 23 is on the front surface side due to the difference in specific gravity before ink curing after the printing step. Thus, the relative position dividing step of dividing the relative position is provided.

That is, in this example, 20 wt% of the transparent beads 22 having an average particle diameter of 22 μm and 65 wt% of the above-mentioned medium of the light transmissive ink and the reflective material 23 of white beads having an average particle diameter of 22 μm are also used. 10 wt%, and further, 5 wt% of a matting agent (matting agent) is added and mixed in order to improve the diffused reflectivity by matting of the diffused reflection substrate 21 itself to form a printing ink, by which the transparent substrate 11 is subjected to the above printing, Immediately after this printing, the transparent substrate 11 is installed upright on the rotary base 30 so that the printing surface is on the outer circumferential side, and the rotary base 30 is rotated to perform a centrifugal separation step. Accordingly, the relative positions of the diffused reflection substrate 21 are divided and the drying is performed together.

As a result, the transparent beads 22 are arranged on the side of the transparent substrate 11 so as to form an intermediate diffused reflection layer on the diffuse reflection substrate 21, and the reflective material 23 formed of white beads is the surface side reflection layer. The relative position is arranged on the surface side of the irregular reflection substrate 21 so as to form the irregular reflection means 20. At this time, it is recognized that the volume of the medium is reduced by drying, and the irregular reflection substrate 21 holds the transparent beads 22 and the reflective substance 23 in this reduced state.

In the liquid crystal backlight A of this example,
The brightness is 2,800 cd / m ² , which is 45% higher than that of the conventional liquid crystal backlight.
With the same brightness as that of No. 1, a uniform result was obtained. The edge light panel 10 of this liquid crystal backlight A
When the eye is viewed, the diffused reflection means in the conventional edge light panel shines gently, but it shines violently and violently, and the amount of illumination light supplied for illumination as the edge light panel 10 increases dramatically. It was confirmed that

It should be noted that the improvement in brightness over the conventional one is also considered to contribute to the increase in the amount of reflected light due to the use of the bag-shaped reflection sheet 2, but the contribution is 1
It is about 5%, and the contribution of the irregular reflection means 20 occupies a large weight of about 30%.
When 0, the diffused reflection substrate 21 performs diffused reflection by itself, and the fine transparent beads 22 arranged at the relative position on the transparent substrate 11 side so as to form an intermediate diffused reflection layer further promotes diffused reflection of incident light, while the surface side reflection layer The reflective material 23 of the granular fine white beads arranged with the relative position as the surface side so as to form the diffuse reflection is sufficiently reflected to the transparent substrate 11 side, and the incident light is emitted from the diffuse reflection substrate 21. It is recognized that this is because the incident light is used as illumination light as much as possible while preventing loss.

By the way, the light-transmissive ink forming the diffuse reflection substrate of the present invention uses the above-mentioned medium, and if necessary, a small amount of a matting agent may be added to obtain good results. The need to add other foreign substances used to promote is generally small.

The fine transparent beads are preferably selected on the basis of the above-mentioned average particle size. In this case, a relatively large variation in particle size is generally observed, but the left and right influence the brightness and uniformity. Therefore, these particle size variations can tolerate this.

As the fine reflective material, granular or powdery materials such as white or silvery can be used. Therefore, in general, in addition to the above-mentioned titanium oxide, which has a relative gravity difference with transparent beads, clay, zinc white, Gloss white, barium sulfate, alumina white, aluminum powder or the like can be used as a single substance or can be used by being enclosed in resin beads as described above, for example.

The fine transparent beads and the fine reflective substance substantially form an intermediate reflection layer in the former and a surface side reflection layer in the latter, respectively, to promote irregular reflection, and to diffuse incident light to the transparent substrate side. The light may be reflected, and generally, for example, with 5 wt% to 25 wt% as a reference, it is sufficient to make the total about 30 wt%.

Resin beads are used for the fine transparent beads or the reflective beads as the fine reflective material.
As described above, it is convenient to prevent damage to the diffuse reflection substrate even if the edge light panel receives a shock, and it is sufficient for improving the brightness, but if this shock is absorbed and prevented, etc. It is possible to use glass beads, and it is also possible to use resin beads and glass beads together.

The relative position dividing step for manufacturing the diffuse reflection means may be the above-mentioned centrifugal separating step, or another method capable of making a difference due to the difference in specific gravity. For example, it may be a natural drying process. In this case, the use of a drying accelerator is avoided, and an ink slow-drying agent is used to prevent drying while forming a section due to a difference in specific gravity. To be dried downward. When isophorone is further added as the slow-drying agent to the light-transmitting ink of medium, the natural drying is performed for about 30 to 40 minutes in a clean atmosphere at room temperature to obtain fine transparent beads and granular particles. The relative position of the powdery fine reflective material can be divided, and the ink can be cured together.

Further, the irregular reflection means is replaced with the above-mentioned halftone dot pattern, and other dot-like or linear patterns are used, and curing is performed by passing through a heating atmosphere for curing the light-transmitting ink at each relative position division step. In implementing the present invention, including adding a accelerating step, providing a primary light source on one incident end face side, and using a pattern for one side light source, etc.,
Specific material, structure, shape, size, quantity, printing process, relative position classification process of transparent substrate, light-transmitting ink, diffuse reflection substrate, fine transparent beads, fine reflection substance,
The means, the specific configuration of the edge light panel, the use, addition to these, and the like can be variously modified without departing from the spirit of the invention, and are not limited to those shown and described above. Absent.

[0029]

As described above, according to the present invention, the diffused reflection means of the edge light panel is arranged at a relative position so as to form a diffused reflection base made of a light transmissive ink printed on a transparent substrate and an intermediate diffused reflection layer on the diffuse reflection base. It is characterized by comprising fine transparent beads arranged on the transparent substrate side, and granular or powdery fine reflective substances arranged on the diffuse reflection substrate at the relative position so as to form a surface-side reflection layer on the diffuse reflection substrate surface side. Therefore, it is possible to realize a dramatic improvement in brightness of several percent or more compared to the conventional one, and it is also a high-brightness edge light that is suitable for use as a liquid crystal backlight for color liquid crystal display surfaces. Panels can be provided.

Further, the manufacturing method includes a printing step of printing on a transparent substrate with a light-transmissive ink in which fine transparent beads having a difference in specific gravity and a fine reflective material in the form of granules or powder are mixed, and the printing step. Since it is characterized in that it is provided with a relative position dividing step for dividing relative positions so that the transparent beads are on the transparent substrate side and the reflective material is on the surface side by the difference in specific gravity before the subsequent ink curing, By the printing process and the relative position dividing process such as centrifugal separation and natural drying, the high-intensity edge light panel can be easily and surely obtained without any complicated process or operation.

[Brief description of drawings]

 Fig. 1 Exploded perspective view of liquid crystal backlight Fig. 2 Longitudinal sectional view of liquid crystal backlight Fig. 3 Longitudinal sectional view showing model of diffuse reflection means Fig. 4 Longitudinal sectional view showing model of fine reflective material Fig. 5 Plan showing centrifugal separation step Figure

[Explanation of symbols]

 A Liquid crystal backlight 10 Edge light panel 11 Transparent substrate 20 Diffuse reflection means 21 Diffuse reflection base 22 Fine transparent beads 23 Fine reflection substance

Claims (7)

[Claims] 1. A diffused reflection substrate formed of a light-transmissive ink printed on a transparent substrate, fine transparent beads whose relative positions are arranged on the transparent substrate side so as to form an intermediate diffused reflection layer on the diffused reflection substrate, and a surface of the diffuse reflection substrate. An irregular diffuser means for an edge light panel, comprising a granular or powdery fine reflective substance arranged in a relative position on the diffused reflector substrate surface side so as to form a side reflective layer. 2. Diffuse reflection means for an edge light panel, characterized in that the reflective material according to claim 1 is used as reflective beads in which a reflective agent is encapsulated. 3. A diffuse reflection means for an edge light panel, wherein the reflective beads of claim 2 are white beads in which a white pigment is encapsulated. 4. A diffuse reflection means for an edge light panel, wherein the reflective substance according to claim 1 is a white pigment. 5. A printing step of printing on a transparent substrate with a light-transmissive ink in which fine transparent beads having a specific gravity difference and a fine reflective substance in the form of particles or powder are mixed, and before the ink curing after the printing step. And a relative position dividing step of dividing relative positions so that the transparent beads are on the transparent substrate side and the reflective material is on the front side according to the difference in specific gravity. 6. The method of manufacturing a diffused reflection means of an edge light panel, wherein the relative position division step of claim 5 is a centrifugal separation step. 7. The method for manufacturing a diffused reflection means of an edge light panel, wherein the relative position classification step of claim 5 is a natural drying step of downward drying of a printing surface in a slow dry state with an ink slow drying agent.