JPH09106571A - Light reflector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve adhesion and reflecting property by successively forming an Al2 O3 or SiO2 layer and an Ag layer by sputtering on a resin substrate. SOLUTION: An Al2 O3 or SiO2 layer and an Ag layer are successively formed by sputtering on a resin substrate to obtain the objective light reflector. The reflectance of a reflecting layer disposed on an optical disk or a liq. crystal display body is preferably >=90%. Since the Ag reflecting layer of this reflector is formed by sputtering, Ag covers the substrate even in the case of a complex shape and the Ag layer of a uniform thickness can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light reflector having a high reflectance reflecting layer on a resin substrate.

[0002]

2. Related Art and Problems to be Solved by the Invention
In recent years, optical discs, liquid crystal displays, and the like have been receiving attention as information media. A reflective layer is provided on these information media to read information by reflected light or display information by reflected light. A commonly used reflective layer is a resin or glass substrate on which an Al layer is formed by sputtering or vacuum deposition.

The Al layer is inexpensive but has a low reflectance and is not suitable for an information medium which requires a high reflectance. Therefore, a medium using an Ag reflecting layer using Ag, which is expensive but has high reflectance, has been proposed. However, the Ag reflective layer has poor adhesion to the resin substrate, and in particular, the Ag reflective layer is easily peeled off when the resin substrate has a complicated shape. Therefore, there has been a demand for a light reflector having a highly reflective Ag reflective layer on a resin substrate having a complicated shape.

[0004]

The gist of the present invention is that an Al ₂ O ₃ layer or SiO ₂ layer formed by sputtering and an Ag layer formed by sputtering are sequentially provided on a resin substrate. It is a characteristic light reflector.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, Al ₂ is formed on a resin substrate.
An O ₃ layer or SiO ₂ layer is formed by sputtering. Even if a resin substrate having a complicated shape is formed by using sputtering, for example, a resin substrate having uneven pits such as an optical disc, Al
₂ O ₃ or SiO ₂ can be wrapped around to form a layer having a uniform thickness.

The Al ₂ O ₃ layer or SiO ₂ layer has excellent adhesion to the Ag layer. However, if the layer thickness is less than 10 nm, the thickness is insufficient to form a layer, and if it exceeds 30 nm, the tensile stress of the layer becomes too large, and the adhesion decreases.
In producing the Al ₂ O ₃ layer or the SiO ₂ layer,
There is a method of using Al ₂ O ₃ or SiO ₂ for the target, a method of using Al or Si for the target, and introducing oxygen gas during sputtering.

An Ag layer is formed on the Al ₂ O ₃ layer or the SiO ₂ layer by sputtering. The reflectance of the reflective layer provided on the optical disc or the liquid crystal display is 90%.
It is preferable that it is above. The Ag reflective layer has a purity of 95.
% Or more, the reflectance of the reflective layer can satisfy 90% or more, and the other 5% is not particularly limited. In the present invention, since the Ag reflective layer is formed by sputtering, it is possible to form an Ag layer having a uniform thickness and having a uniform thickness.

The resin used for the substrate is not particularly limited, but resins generally used for optical disks or liquid crystal displays are, for example, polycarbonate (hereinafter abbreviated as PC) resin or polymethylmethacrylate (hereinafter,
It is a resin (abbreviated as PMMA). In addition, an organic or inorganic protective layer may be provided in order to prevent corrosion resistance of the Ag layer.

[0009]

【Example】

(Example 1) A layer thickness of 2 was formed by a RF magnetron sputtering method on a substrate made of PC resin having fine irregularities on its surface.
After forming a 0 nm Al ₂ O ₃ layer, a 200 nm thick Ag reflective layer was formed by a DC sputtering method. Further, an ultraviolet curable resin was applied and cured to obtain a light reflector having an Ag layer.

(Embodiments 2 and 3) Embodiment 2 is A of Embodiment 1.
Example 1 except that a SiO ₂ layer was used instead of the l ₂ O ₃ layer.
A light reflector was obtained in the same manner as. Example 3 is P of Example 1.
A light reflector was obtained in the same manner as in Example 1 except that the PMMA resin substrate was used instead of the C resin substrate.

(Comparative Examples 1 and 2) An Ag reflective layer having a layer thickness of 200 nm was directly formed on a substrate made of PC resin having fine irregularities on its surface by a DC sputtering method. further,
An ultraviolet curable resin was applied and cured to obtain a light reflector of Comparative Example 1 having an Ag layer. A 200 nm layer thickness A was directly deposited on a substrate made of PC resin with minute irregularities on the surface by vapor deposition.
A g-reflecting layer was formed. Further, an ultraviolet curable resin was applied and cured to obtain a light reflector of Comparative Example 2 having an Ag layer.

The adhesion, throwing power and reflectance of the light reflectors obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were examined.
The results are summarized in Table 1. For the adhesiveness, the peeling state of the Ag layer when the tape was peeled off after the tape was stuck on the surface of the light reflector was examined. The judgment is as follows. In the case of ○, peeling did not occur. × produced peeling.

The throwing power was visually examined on the substrate surface.
The judgment is as follows. In the case of ◯, the Ag layer was formed on the entire surface of the substrate. In the case of ×, the Ag layer was not partially formed.
The reflectance was such that the substrate surface was irradiated with a laser of 633 nm. The judgment is as follows. ◯ has a reflectance of 90% or more. X has a reflectance of less than 90%.

[0014]

[Table 1] As shown in Table 1, Examples 1 to 1 which are light reflectors of the present invention
No. 3 has excellent adhesiveness, throwing power and reflectance, but Comparative Examples 1 and 2 not having an Al ₂ O ₃ layer or a SiO ₂ layer have a reflectance of Ag because the reflecting layer is Ag. Although satisfactory, the adhesion and throwing power of the Ag layer are poor.

[0015]

EFFECT OF THE INVENTION It is possible to obtain a light reflector having an Ag reflection layer having excellent adhesion to a resin substrate having a complicated shape.

Claims (1)

[Claims] 1. A light reflector comprising an Al ₂ O ₃ layer or SiO ₂ layer formed by sputtering and an Ag layer formed by sputtering, which are sequentially provided on a resin substrate.