JPH0799417B2 - Edge light panel - 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 used for an edge light panel illuminating device such as a liquid crystal backlight and an illuminated signboard.

[0002]

2. Description of the Related Art In general, an edge light panel of this kind is one in which a surface of one side of a transparent substrate made of acrylic resin or the like is provided with a diffuse reflection surface having a predetermined pattern by a printing means such as screen printing. The diffused reflection of the incident light supplied to the end face of the transparent substrate illuminates the light source in the direction away from the light source with a luminance as uniform as possible.

Regarding the irregular reflection surface formed on the transparent substrate,
For example, JP-A-57-128383 discloses that a white paint coating layer is used, and JP-A-60-205576 discloses that a white ink containing glass beads is used.
No. 0289 uses a matte ink or a white ink, JP-A No. 63-62104 uses a milky white ink containing a fluorescent pigment, and JP-A No. 2-126501 describes the addition amount of a white pigment or a fluorescent pigment. It has been proposed to reduce the concentration of the ink as much as possible and to use a lightening ink containing glass beads.

[0004]

According to these conventional techniques, diffuse reflection is mainly caused by diffuse reflection substances added to the printing ink such as white pigments, fluorescent pigments and matting materials that form the diffuse reflection surface. It is assumed that the glass beads are supplementarily added to this, and diffuse reflection is further promoted.

According to the idea of relying on the diffused reflection substance for the diffused reflection substance, it is possible to secure a certain degree of brightness and uniformity, and the above-mentioned Japanese Patent Laid-Open No. 63-63.
-62104 has achieved the practical application of this kind of edge light illuminating device as an alternative to the direct type illuminating device, and Japanese Patent Laid-Open No. 126501/1990 is evaluated as having improved its brightness.

However, in the edge light panel that relies on diffused reflection by the diffused reflection material as described above, it is relatively easy to generate an edge light panel which has a phenomenon of abnormal light emission that appears as a dot-like shine. Since abnormal light emission must generally be treated as a defective product, abnormal light emission causes a decrease in production yield.

Further, when it is attempted to mass produce an edge light panel by forming the irregular reflection surface by screen printing, the plate is likely to be clogged, and the printing defect tends to occur due to the clogging. In order to avoid it, frequent plate cleaning is indispensable, which is complicated and causes a decrease in productivity.

On the other hand, although the edge light panel having these irregular reflection surfaces can have considerable brightness and uniformity as described above, it is still necessary to use it for a liquid crystal backlight of a color liquid crystal display surface. There is a strong shortage of
There is a situation in which it is required to provide a brighter edge light panel by further improving the brightness including the case where it is used for the color liquid crystal display surface.

The present invention has been made under the above circumstances, and its object is to prevent the production of defective products due to the abnormal light emission and also to increase the production complexity due to plate clogging during production. The present invention is to provide a novel edge light panel that eliminates this problem and can further improve the brightness achieved by the conventional edge light panel.

[0010]

When the cause of abnormal light emission of the above edge light panel and clogging at the time of production was searched for, all of these were caused by diffuse reflection substances such as the above-mentioned pigments used for performing diffuse reflection. The fact that we are doing is revealed.

That is, the abnormal light emission means that the diffuse reflection substance is a solid substance, and therefore the foreign substance as the solid substance is mixed in the diffuse reflection substrate. For example, when a slight impact is applied, the mixture distribution The diffuse reflection material acts to cause the diffuse reflection substrate to partly fracture along the material due to the state, shape, etc., and when the fracture missing occurs, that portion of the diffuse reflection substrate, for example, the surface side This is due to the fact that incident light diffuse reflection changes at the rupture-missing part that occurred in the shoulder, and clogging is caused by the diffuse reflection material dispersedly contained in the printing ink being caught in the micropores of the plate. However, it is caused by the tendency that the printing ink and the printing ink cannot pass through the fine holes smoothly, and that the fine holes are gradually closed.

Thus, from the fact that the diffuse reflection material used to depend on the diffuse reflection originally has a causal relationship with the above-mentioned abnormal light emission and clogging, the inventors of the present invention have conducted extensive studies, and as a result, The diffuse reflection substrate is made of a light-transmissive ink by not containing these diffuse reflection substances, or by making the diffuse reflection substance very small, and by using fine beads encapsulating the diffuse reflection substance instead of the diffuse reflection substance, It is a means of effectively suppressing the above-mentioned abnormal light emission and clogging that the surface is constituted by the diffused reflection substrate and the diffused substance-encapsulated fine beads, and by doing so, the brightness of the edge light panel is increased. It was found that the light-transmissive ink diffuses the diffuse reflection substrate substantially in the ink vehicle, the medium, Of the transparent ink component, the diffused reflection material to be encapsulated in the fine beads is a white pigment such as white or milky white, and the fine beads are made of synthetic resin such as acrylic so as to have elasticity. Found some facts that each yielded better results.

The present invention has been made on the basis of such knowledge, that is, the present invention has a predetermined pattern formed by a diffused reflection substrate made of a light-transmitting ink and fine beads having a diffused reflection substance enclosed in a hollow portion. An edge light panel (claim 1), characterized by comprising a diffused reflection surface, and a diffused reflection substrate made of the light-transmissive ink according to claim 1,
An edge light panel characterized by comprising substantially only a transparent ink component (claim 2), and an edge light panel characterized by comprising the diffuse reflection material of claim 1 or 2 as a white pigment (claim Item 3) and the fine beads of Claims 1 to 3 are made of synthetic resin so as to have elasticity, and an edge light panel (Claim 4). Is the means of.

[0014]

In the present invention, the incident light reaching the diffused reflection substrate by the light-transmitting ink is directly supplied to the fine beads in a strong state without being diffused by foreign matter as much as possible, and the diffused reflection substance is prevented. The encapsulated fine beads sufficiently diffusely reflect it, and are also supplied to the illumination surface direction without being affected by foreign matter to perform high-intensity illumination and to be supplied in the in-plane direction to guide light. To work.

Further, since the fine beads generally have a spherical shape, the contact area with the diffuse reflection substrate is expanded and good adhesion is obtained, so that the fine beads act to prevent breakage and breakage of the diffuse reflection substrate, and at the time of printing. The micropore passing property is improved and it works to prevent clogging.

Further, the fine beads are made of synthetic resin so as to have elasticity, so that they act to absorb impact and enhance the resistance to the fracture breakage.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the drawings showing the following examples. A is a liquid crystal backlight, and the liquid crystal backlight A is, for example, 75
A diffusion sheet 1 made of a milky white polyester film having a thickness of μm 1, an edge light panel 10 and a reflection sheet 2 made of a white polyester low-foaming film having a thickness of 188 μm are laminated and arranged, and one end face of the edge light panel 10 is used as an incident end face 12, A tube-shaped primary light source 3 made of a cold cathode tube is provided in front of the incident end face 12, and in this example, it is mainly configured for a monochrome liquid crystal display surface.

The edge light panel 10 is, for example, 1.5
A diffuse reflection surface 20 is provided on one side surface of the transparent substrate 11 made of acrylic resin having a thickness of 130 mm × 160 mm, particularly on the back side thereof.

The irregular reflection surface 20 is formed as a set of halftone dots so as to present a predetermined pattern, that is, a halftone dot pattern in the present example, and this pattern is arranged from the incident end face 12 side in a halftone dot-like matrix pattern. While the halftone dot area ratio is gradually increased in the inward direction of the light source separation plane without changing the positional relationship, the maximum halftone dot area ratio portion 21
Is disposed between the incident end face 12 and the non-incident side facing end face at an in-plane intermediate position deviated to the facing end face side. The maximum area ratio portion 2 is provided by receiving the reflected light from the reflection means such as installation to suppress the improvement of the brightness portion in the vicinity thereof and bringing the maximum area ratio portion 21 closer to the primary light source 12 side.
The luminance of 1 is used as a reference so that uniform illumination can be performed.

The diffused reflection surface 20 formed by the halftone dot pattern having the gradually increasing area ratio is constructed such that each halftone dot is composed of a diffused reflection substrate 22 made of a light-transmitting ink and fine beads 23 in which a diffuse reflection substance 24 is enclosed in a hollow portion. is there.

Diffuse reflection substrate 22 made of this light-transmitting ink
Is composed of only a transparent ink component so as to make it as transparent as possible. In this example, 100% of a medium having the same composition as an ink vehicle generally used for ink thinning is used. This diffuse reflection substrate 22 is configured.

The fine beads 23 enclosing the diffuse reflection material 24 are synthetic resin beads, especially acrylic transparent beads, and the hollow portion thereof is filled with fine powder of titanium dioxide, which is a typical white pigment as the diffuse reflection material. The fine beads 23 are used as a foreskin of the reflective material 24, so that the diffused reflective material 24 is enclosed.
And has elasticity.

The fine beads 23 are randomly dispersed in the diffuse reflection substrate 22 as shown in FIG. 2, and the diffuse reflection substrate 22 has a white pigment or fluorescent pigment other than the fine beads 24. The foreign substances such as matting agents are not directly dispersed and contained.

The irregular reflection surface 20 is formed by the irregular reflection substrate 22 and the fine beads 23 by screen-printing the transparent substrate 11. In this example, the irregular reflection substance 24 is added to the medium. The screen printing may be performed by a conventional method using a mixture of the encapsulated fine beads 23 as an ink for screen printing.

The fine beads 23 generally have an outer diameter of 3
It is preferable to use one having a thickness of 0 μm or less in order to almost completely eliminate clogging during printing, and the amount thereof should be in the range of 10% to 20% by weight ratio in the printing ink. It is preferable to prevent breakage and breakage of 22 and to secure high brightness.

FIG. 4 shows another example of the irregular reflection surface 20, that is, in this example, the arrangement of the fine beads 23 encapsulating the irregular reflection substance 24 is unevenly distributed near the surface of the irregular reflection substrate 22. Is done. By subjecting the fine beads 23 randomly arranged to screen printing using a slower drying medium, the fine beads 2
Due to the difference in specific gravity from No. 3, such an arrangement can be achieved before the drying and curing.

The edge light panel provided with the irregular reflection surface by these can provide uniform illumination exhibiting a high brightness of about 250 cd / m ^{2 to} 300 cd / m ² , and for example, the lightening density of JP-A-2-126501 can be achieved. As compared with the case where the ink is used under the same conditions, the result that the brightness is improved by about 20% is obtained, and the impact is applied to each of a large number of sheets, or the external force is applied to rub the irregular reflection surface. No abnormal light emission was observed, and printing defects due to clogging during screen printing were not likely to occur, and the plate cleaning interval was greatly extended.

Although the illustrated example is as described above, in the practice of the present invention, the diffuse reflection substrate of the light transmitting ink is mainly composed of the transparent ink component such as the ink vehicle and the medium, and the above light transmitting property is sufficiently secured. Including the small amount of foreign matter within the range, the fine beads to be transparent glass beads, the use of synthetic resin other than acrylic, and the conventional diffuse reflection surface other than titanium dioxide as the diffuse reflection material. Other than those used in the above, or a mixture thereof, other than the above-mentioned halftone dot pattern is used as the predetermined pattern, and a primary light source of the same wattage is provided on each of the pair of end faces for forming the halftone dot pattern. Edge light that gradually increases the area ratio so that the maximum area ratio part is located in the center between the light sources in the case of dual-sided light sources Each of the diffused substrates, diffused substances, fine beads, diffused reflection surfaces, and transparent substrates can be used in a specific shape, structure, size, etc. The amount, the material, the specific means for forming the irregular reflection surface, and the like can be variously changed without departing from the gist of the invention, and it is not necessary to be limited to those specifically illustrated or described above.

[0029]

As described above, the present invention is characterized by comprising a diffused reflection surface of a predetermined pattern constituted by a diffused reflection substrate made of a light-transmitting ink and fine beads having a hollow portion filled with a diffuse reflection substance. As a result, since the fine beads have a spherical shape, the contact area with the diffuse reflection substrate is expanded and mutual adhesion is satisfactorily obtained, preventing breakage of the diffuse reflection substrate and preventing abnormalities in the diffuse reflection surface due to the breakage. Prevents emission of light, improves the ability to pass through the plate micropores during printing to prevent clogging, prevents printing defects due to clogging, and reduces the number of plate washings as much as possible. At least improve workability.

Further, the incident light reaching the diffuse reflection substrate by the light-transmissive ink is directly supplied to the fine beads in a strong state without being diffused by the foreign substance to the diffuse reflection substrate as much as possible, and the fine particles enclosing the diffuse reflection substance are enclosed. The beads sufficiently diffuse and reflect them, and are also supplied in the direction of the illumination surface without being affected by foreign matter to perform high-intensity illumination and improve the brightness, and are also supplied in the in-plane direction to enhance the light guiding property. .

Further, by forming the diffused reflection substrate substantially only by the transparent ink component to enhance the light transmittance,
The brightness and light guiding property are more preferably improved, the diffuse reflection property of the fine beads is highly ensured by using a diffuse pigment as a white pigment, and the fine beads are made of synthetic resin so as to have elasticity. The possibility of breakage breakage of the irregular reflection substrate is further reduced, and the possibility of abnormal light emission due to this is more reliably prevented.

As described above, the present invention provides an edge light panel which suppresses the generation of defective products due to abnormal light emission, eliminates the complexity of production due to plate clogging at the time of production, and at the same time improves brightness. Can be provided.

[Brief description of drawings]

 Fig. 1 Exploded perspective view of LCD backlight Fig. 2 Enlarged vertical sectional view of diffuse reflection surface Fig. 3 Enlarged vertical sectional view of fine beads Fig. 4 Enlarged vertical cross section of irregular reflection surface according to another example

[Explanation of symbols]

 A Liquid crystal backlight 10 Edge light panel 11 Transparent substrate 20 Diffuse reflection surface 22 Diffuse reflection substrate 23 Fine beads 24 Diffuse reflection material

Claims (4)

[Claims] 1. An edge light panel comprising a diffuse reflection surface of a predetermined pattern, which is constituted by a diffuse reflection substrate made of light transmissive ink and fine beads having a diffuse reflection substance enclosed in a hollow portion. 2. An edge light panel, characterized in that the diffuse reflection substrate made of the light transmissive ink of claim 1 is constituted substantially only by a transparent ink component. 3. An edge light panel, wherein the diffuse reflection material according to claim 1 or 2 is a white pigment. 4. An edge light panel, characterized in that the fine beads of claim 1 are made of synthetic resin so as to have elasticity.