JPH05162227A - Reflector - Google Patents

Abstract

PURPOSE:To provide a reflector with excellent durability. CONSTITUTION:By laminating a metallic thin film containing silver on the one surface of a flexible base plate having transmittance of 10% or less in a wave length of 380-100nm, a reflector is improved in its durability against light, heat or the like without significantly lowering the reflectance of visible rays. In this way, the deterioration of the reflector due to light or heat is restrained and thereby the durability and practicability of the reflector is improved.

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 highly reflective metal thin film laminated on a flexible substrate. An application of the reflector according to the present invention is a reflector such as a mirror that is easily manufactured. The reflector of the present invention can be easily attached to a glass plate such as a window, a door or a windshield, a plastic plate, a metal plate or the like by using an adhesive, an adhesive or a double-sided tape.

The present invention is a reflector having significantly improved durability, and has a high reflectance and a high reliability in a reflector of a fluorescent lamp (such as a lamp house) as a backlight of a liquid crystal display panel of a computer or a computer. Can be used. Further, it is useful for energy saving of office lighting as a reflector of a fluorescent lamp utilizing high reflectance.

[0003]

2. Description of the Related Art A light-reflecting film based on a plastic film is lighter in weight, superior in impact resistance and more flexible than a mirror based on glass. It is used as a copier, a solar heat collector, a light reflector for a plant factory, a high-reflector for fluorescent lamps, and a reflector for a backlight of a liquid crystal display device.

Conventionally, as these reflectors, those obtained by polishing an aluminum plate or a stainless plate, or those obtained by laminating a thin film of a metal such as aluminum or silver on a plastic film have been used.

However, a coating film made of an aluminum vapor deposition product, a stainless steel plate, a resin or the like had a low reflectance and was completely inadequate. In addition, a light reflector with a silver thin film layer formed on a general-purpose plastic film has a high reflectance when manufactured, but due to environmental factors such as heat and light, the reflectance of the reflector is remarkably reduced by ultraviolet rays. However, there is a technical problem that the function of the backlight as a reflector is not satisfied.

[0006]

SUMMARY OF THE INVENTION The present invention is to provide a reflector having excellent durability and high reflectance.

[0007]

[Means for Solving the Problems]
By laminating a thin film of a metal containing silver on a flexible substrate having a transmittance of light with a wavelength of 00 nm of 10% or less, durability can be improved without lowering the reflectance of the reflector. Then, the present invention has been completed.

That is, according to the present invention, a flexible substrate as a base material of a reflector has a transmittance of light of 10% or less for a wavelength of 380 to 300 nm. It is a reflector characterized by laminating a thin film of a metal containing silver on.

The flexible substrate used in the present invention preferably has a light transmittance at a wavelength of 550 nm of 70% or more, preferably at least 80%, and a light transmittance of a wavelength of 380 to 300 nm. It is desirable that the rate is 10% or less, preferably 1% or less.

The preferred flexible substrate for use in the present invention is a film or sheet made of a homopolymer or copolymer having a transmittance of light of 380 to 300 nm of 10% or less, an ultraviolet absorber, etc. It is a certain plastic film or sheet, a plastic film or sheet on which a layer that blocks ultraviolet rays such as an ultraviolet absorber or zinc oxide is formed.

Examples of preferable flexible substrates include biaxially oriented polypropylene containing an ultraviolet absorber, polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and polybutylene terephthalate (PB).
Examples thereof include homopolymers or copolymers of T), acrylic resins, methacrylic resins, polyetheretherketones, polyarylates, polyetherimides and the like. In particular, PET containing an ultraviolet absorber is preferably used.

[0012] The thickness of the plastic film is preferably thin from the viewpoint of cost reduction of the reflector or productivity in imparting functionality, and in view of the winding property (handling property) in imparting functionality, the thickness of the plastic film is reduced. Thick things are easy to handle. The thickness of the film is preferably 5 μm or more, more preferably 25 μm or more, and 250 μm or less.

In a preferred embodiment of the present invention, a silver thin film layer is laminated on a PET containing an ultraviolet absorber, and the thin film is formed by a plating method, vacuum deposition, sputtering, ion plating, Ionization vapor deposition, ion cluster beam vapor deposition and the like can be used.

The thickness of the metal thin film layer containing silver is 200 to 5000.
Å is preferable, and 500 to 2000 Å is more preferable. More preferably, it is 800 to 1500Å. The fact that the metal thin film layer containing silver contains a trace amount of metals and metal compounds other than silver does not impair the object of the present invention. Further, a metal layer having anticorrosion property can be formed on the outermost layer of the metal thin film layer.

The reflector of the present invention may be provided with a transparent protective layer on the plastic film opposite to the metal layer. With such a protective layer, the influence of external environmental factors such as surface hardness, light resistance, gas resistance, and water resistance of the reflector can be further suppressed.

Examples of substances that can be used to form such a protective layer include acrylic resins such as polymethylmethacrylate, polyacrylonitrile resins, polymethacrylonitrile resins, and silicon resins such as polymers obtained from ethyl silicate. In addition to organic substances such as polyester resin and fluororesin, inorganic substances such as silicon oxide, zinc oxide, and titanium oxide are useful. Especially, the transmittance of light having a wavelength of 400 nm or less, preferably 380 nm or less is 10% or less. It is preferable to stack those having the ability to cut.

Examples of the method for forming the transparent protective layer include coating and film laminating. Also,
These film thicknesses are required to be in a range that exerts a protective effect without deteriorating the light reflectivity, which is the object of the present invention, and are appropriately changed and used according to the material and application. Less than,
The present invention will be described in more detail by way of examples.

[0018]

【Example】

Example 1 Layer containing benzotriazole-based UV absorber (5 μm)
A silver (1000Å) thin film layer was formed on the biaxially stretched polyethylene terephthalate film having a thickness of 50 μm provided by means of DC magnetron sputtering to obtain a reflector. The transmittances of light having wavelengths of 380, 350 and 300 nm before forming the silver thin film layer are shown in Table 1 and FIG. UV deterioration accelerating test of this reflector (Specifically,
The reflector is irradiated with light with a wavelength of 315 nm)
The time until the reflectance of incident light of nm reaches 80% of the initial value was measured as the deterioration time. Table 2 shows the results and the reflectance before the UV deterioration accelerating test. As you can see, the deterioration time
It had excellent durability of 5000 hours or more.

Comparative Example 1 A silver thin film having a thickness of 1000 Å was formed by the same method as in Example 1 on a normal biaxially stretched polyethylene terephthalate film having a thickness of 50 μm. The light transmittances at wavelengths of 380, 350 and 300 nm before forming the silver thin film layer are shown in Table 1 and FIGS. It was found that this reflector turned red-purple upon irradiation with ultraviolet rays for 100 hours, and the reflectance decreased to 80% of the initial value after irradiation with ultraviolet rays for 400 hours, indicating that the durability against ultraviolet rays was extremely poor.

Example 2 50 μm thick acryprene film (manufactured by Mitsubishi Rayon)
A silver (1200Å) thin film layer was formed on the top by vacuum evaporation to obtain a reflector. 380, 350 and before forming silver thin film layer
The transmittance of light having a wavelength of 300 nm is shown in Table 1 and FIGS. Table 2 shows the results of the ultraviolet deterioration acceleration test performed in the same manner as in Example 1. Like Example 1, it had excellent light reflectance and durability.

Example 3 On a 50 μm thick Tetron HB film (manufactured by Teijin), a silver thin film having a thickness of 1000 Å was formed by the same method as in Example 1 to obtain a reflector. 380, 350 and before forming silver thin film layer
The transmittance of light having a wavelength of 300 nm is shown in Table 1 and FIG. An evaluation test was conducted in the same manner as in Example 1, and the results are shown in Table 2. Like Example 1, it had excellent light reflectance and durability.

Example 4 The film used in Example 2 was attached to the opposite surface of the light reflector produced in Comparative Example 1 with a silicone adhesive. 38
Table 1 shows the transmittance of light having wavelengths of 0, 350 and 300 nm. An evaluation test was conducted in the same manner as in Example 1, and the results are shown in Table 2. Like Example 1, it had excellent light reflectance and durability.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

As shown in the examples, according to the present invention, the durability as a reflector is remarkably improved due to the improved durability against light and heat.

The reflector of the present invention is lightweight, has excellent impact resistance, is flexible, and is used as a mirror, as well as a reflector for saving power in a plant factory, and an energy-saving type high-reflection fluorescent lamp. Also, it is effectively used as a high-brightness reflector of a backlight for liquid crystal display panels.

[Brief description of drawings]

FIG. 1 shows the light transmittance of a flexible substrate used in the present invention.

[Explanation of symbols]

 1 Light transmittance of the films of Examples 1 and 3 2 Light transmittance of the film of Example 2 3 Light transmittance of the film of Comparative Example

Claims (1)

[Claims] 1. A reflector in which a metal thin film containing silver is laminated on one surface of a flexible substrate having a light transmittance of 10% or less at a wavelength of 380 to 300 nm.