JP2747670B2 - Transfer foil for light guide plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer foil for a light guide plate for transferring light to a side surface of a light guide plate in a backlight device such as a personal computer, a word processor, a liquid crystal display, an illuminator, and a sign.

[0002]

2. Description of the Related Art Conventionally, a white film such as a metal-deposited film, a foamed white film, or a white film in which a pigment is mixed and mixed is adhered to the side surface of a light guide plate to reflect and diffuse light without escaping. .

[0003]

However, since the light guide plate is thin, it is not easy to attach a metal vapor-deposited film or a white film on its side surface. In particular, the thickness of the light guide plate is 5 mm.
In the case of the following, since the side face is very elongated, it has been difficult to attach a metal-deposited film or a white film successfully. Also, when the side surface of the light guide plate is tapered, it has been difficult to attach a metal vapor-deposited film or a white film to the side surface regardless of the thickness of the light guide plate. Furthermore, when a metal-deposited film is bonded, the reflection direction is limited to a fixed direction because the metal-deposited layer of the metal-deposited film is a mirror surface.
The light was not sufficiently diffused and the luminance was not sufficient. further,
When the white film was bonded, the light was not reflected at all and passed through the white film and escaped, so that the light was not sufficiently reflected and the luminance was not sufficient. Furthermore, when the side surface of the light guide plate is tapered, the narrow portion of the tapered shape may be too thin to attach a metal-deposited film or a white film. In this case, light is transmitted and escapes from a portion where the metal film or the white film is not bonded, so that the light is not sufficiently reflected or diffused and the luminance is not sufficient. The present invention eliminates the above-mentioned disadvantages, without laminating a metal vapor-deposited film or a white film, easily and with good workability regardless of the thinness and shape of the side surface of the light guide plate, reflection of light on the side surface of the light guide plate, An object of the present invention is to provide a transfer foil for a light guide plate that can be processed for diffusion and that sufficiently reflects and diffuses light on the side surface of the light guide plate to obtain sufficient luminance.

[0004]

According to the present invention, a release layer is formed on one side of a plastic film, a metal thin film is formed on the release layer, and a white adhesive layer is formed on the metal thin film. It is a transfer foil for light guide plates characterized by the above-mentioned.

In the transfer foil for a light guide plate according to the present invention, the white adhesive layer side is applied to the side surface of the light guide plate, and the plastic film side is heated and pressurized by a suitable means such as a roll so that the entire surface of the transfer foil for the light guide plate is provided. It is transferred and used. When the light guide plate transfer foil is completely transferred to the side surface of the light guide plate, a white adhesive layer is formed in contact with the side surface of the light guide plate, and a metal thin film is formed outside the white adhesive layer. . Since the transfer foil for a light guide plate according to the present invention may be transferred to the side surface of the light guide plate by a roll or the like, light can be easily and efficiently reflected on the side surface of the light guide plate regardless of the thinness or shape of the side surface of the light guide plate. , Processing for diffusion can be performed.

As the plastic film in the present invention, a plastic film conventionally known as a base material of a transfer foil can be used.

As the release layer, a release layer conventionally known as a release layer of a transfer foil can be used. Specifically, a resin conventionally known as a resin for a release layer is applied to one side of a plastic film. It can be formed by coating.

As the metal thin film, a metal thin film made of various metals, alloys and the like conventionally known as a metal thin film of a transfer foil can be used, and can be formed on a release layer by a conventionally known thin film forming method.

Prior to forming a metal thin film on the release layer,
A metal thin film may be formed on the protective layer by forming a protective layer with an appropriate resin on the release layer, and thus, not only when the metal thin film is formed directly on the release layer, The present invention also includes a case where a metal thin film is formed on a release layer via a protective layer.

The white adhesive layer can be formed by coating a resin, which is conventionally known as a resin for an adhesive layer of a transfer foil, with a white pigment or the like mixed on a metal thin film. Titanium oxide is suitable as a white pigment or the like mixed in the resin. 250 to 5 titanium oxide
It is 50 PHR, preferably 300 to 500 PHR.
The white adhesive layer may contain resin particles such as silica or cellulose powder or acrylic beads, and such a resin is also included in the present invention. Silica or resin fine particles to be contained may be about 10 to 30 PHR, preferably about 15 to 25 PHR. The thickness of the white adhesive layer is about 6 to 12 μm, preferably 8 to 10 μm.

Prior to forming a white adhesive layer on the metal thin film, a primer layer is formed on the metal thin film with the same or different resin as the white adhesive layer, and a white adhesive layer is formed on the primer layer. As described above, not only the case where the white adhesive layer is formed directly on the metal thin film, but also the case where the white adhesive layer is formed on the metal thin film via the primer layer is included in the present invention. .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As a plastic film in a transfer foil for a light guide plate according to the present invention, a plastic film conventionally known as a base material of the transfer foil, such as a polyester film such as a polyethylene terephthalate film or a polypropylene film, can be used. . The plastic film may have been subjected to appropriate unevenness processing such as hair line processing. The thickness of the plastic film is about 12 to 30 μm, preferably about 16 to 25 μm. If the plastic film is thinner than 12 μm, the plastic film will be burned during transfer and adhere to a roll or the like. If the thickness of the plastic film is more than 30 μm, heat is difficult to be transferred during transfer, and transfer is difficult.

A release layer is formed on one side of the plastic film. The release layer is made of acrylic resin, cellulose resin,
It can be formed by coating a resin or wax conventionally known as a resin for a release layer, such as a vinyl resin or an alkyd resin, on one surface of a plastic film.

Prior to forming a metal thin film on the release layer,
When forming a protective layer with an appropriate resin on the release layer,
Acrylic resin, melamine resin, urethane resin, etc.
It can be formed by coating a resin conventionally used for the protective layer of the transfer foil on the release layer.

A metal thin film conventionally known as a metal thin film of a transfer foil is formed directly on the release layer or via a protective layer on the release layer. The metal thin film is made of Al, Ag, Cr, Ni,
A metal thin film made of various metals such as Sn, an alloy, or the like can be formed by a conventionally known thin film forming method such as vacuum evaporation, sputtering, or ion plating. The thickness of the metal thin film is about 250 to 800 °. When the metal thin film is relatively thin, the metal thin film becomes translucent and does not reflect light sufficiently.
About 0 ° is preferable.

Prior to forming a white adhesive layer on a metal thin film, when a primer layer is formed on a metal thin film, a white adhesive such as a vinyl resin, a polyester resin, a cellulose resin, and an acrylic resin is used. It can be formed by coating a resin of the same or different kind with the layer. When a white adhesive layer is formed on a metal thin film via a primer layer,
The adhesion between the metal thin film and the white adhesive layer becomes very strong.

The white adhesive layer is obtained by mixing a resin known as a resin for an adhesive layer of a transfer foil with a white pigment or the like directly on a metal thin film or via a primer layer on a metal thin film. It can be formed by coating. For the adhesive layer, for example, ethylene vinyl acetate resin, acrylic resin, or the like can be used. Titanium oxide is suitable as a white pigment or the like. 250-550PH of titanium oxide
R, preferably 300 to 500 PHR. If the amount of titanium oxide is less than 250 PHR, the luminance is deteriorated. If the amount of titanium oxide is more than 550 PHR, the adhesion when transferring is weakened. The white adhesive layer may contain silica or fine resin particles such as cellulose powder or acrylic beads. When silica or resin fine particles are contained in the white adhesive layer, light is more diffused. The amount of silica or resin particles to be included may be about 10 to 30 PHR,
Preferably, it is about 15 to 25 PHR. The thickness of the white adhesive layer is about 6 to 12 μm, preferably 8 to 10 μm.
μm. When the white adhesive layer is thinner than 6 μm, the luminance is deteriorated. If the white adhesive layer is thicker than 12 μm, it will be too thick to cause cohesive failure, and the transfer foil will be poorly cut. The white adhesive layer adheres when transferring the transfer foil for a light guide plate to the side surface of the light guide plate, and reflects and diffuses light after the transfer.

[0018]

【Example】

Example 1 A release layer having a thickness of 0.1 μm was formed on one surface of a polyester film having a thickness of 16 μm by using a cellulose resin by gravure coating, and a melamine resin was used on the release layer. A protective layer having a thickness of 0.5 μm is formed by gravure coating, an Al vapor deposition layer having a thickness of 500 ° is formed on the protective layer by vacuum vapor deposition as a metal thin film, and titanium oxide is mixed with 300 PHR on the metal thin film. A white adhesive layer having a thickness of 8 μm was formed by reverse coating using the obtained ethylene vinyl acetate resin to obtain a transfer foil for a light guide plate according to the present invention.

Example 2 A release layer was formed on one side of a 25 μm-thick polyester film by gravure coating using a wax, and an acrylic resin was used to form a release layer on the release layer.
Forming a protective layer of 5 μm by gravure coating;
On the protective layer, a metal thin film having a thickness of 40
A 0 ° Ag deposition layer is formed, a 1 μm thick primer layer is formed on the metal thin film using an acrylic resin by reverse coating, and an acrylic resin mixed with 500 PHR of titanium oxide is formed on the primer layer. Was used to form a white adhesive layer having a thickness of 10 μm by reverse coating to obtain a transfer foil for a light guide plate according to the present invention.

[0020]

Since the present invention is constructed as described above, it is easy and easy to work on the side surface of the light guide plate irrespective of the thickness or shape of the side surface of the light guide plate without laminating a metal-deposited film or a white film. An object of the present invention is to provide a transfer foil for a light guide plate that can be processed for reflecting and diffusing light, and that can sufficiently obtain brightness by sufficiently reflecting and diffusing light on the side surface of the light guide plate. . The transfer foil for a light guide plate according to the present invention can be easily transferred regardless of the thinness or shape of the side surface of the light guide plate by simply transferring the light to the side surface of the light guide plate. Is transferred to the side surfaces of many light guide plates in one transfer. When a metal vapor-deposited film was attached to the side surface of the light guide plate, the light was not diffused sufficiently and the luminance was not sufficient because the light reflection direction was limited to a fixed direction. When the transfer foil for the light plate is transferred to the side surface of the light guide plate, a white adhesive layer is formed in contact with the side surface of the light guide plate,
Since light is diffusely reflected by the white adhesive layer and sufficiently diffused, sufficient luminance can be obtained. Moreover, when the transfer foil for a light guide plate according to the present invention is transferred to the side surface of the light guide plate, a metal thin film is formed outside the white adhesive layer, so that light partially passes through the white adhesive layer. However, the transmitted light is reflected by the metal thin film and returns to the light guide plate again, so that the light is sufficiently reflected, and sufficient luminance can be obtained. In addition, even when the side surface of the light guide plate is tapered, simply transferring the light to the side surface of the light guide plate can easily be applied to the tapered portion that is too narrow to be bonded with a metal-deposited film or white film. Can be transferred to
Since the light is sufficiently reflected and diffused without transmitting and escaping from the portion, sufficient luminance can be obtained.

Claims (4)

(57) [Claims] 1. A light guide plate comprising: a release layer formed on one side of a plastic film; a metal thin film formed on the release layer; and a white adhesive layer formed on the metal thin film. Transfer foil 2. The white adhesive layer comprises titanium oxide of 250 to 5
The transfer foil for a light guide plate according to claim 1, which is a white adhesive layer having a thickness of 6 to 12 µm mixed with 50 PHR. 3. A white adhesive layer comprising titanium oxide of 300 to 5
3. The transfer foil for a light guide plate according to claim 1, which is a white adhesive layer having a thickness of 8 to 10 [mu] m mixed with 00PHR. 4. The transfer foil for a light guide plate according to claim 1, wherein the white adhesive layer contains 10 to 30 PHR of silica or resin fine particles.