JPS6191838A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To enable east mass production and obtain high reflection preventing effect and reliability by providing a film consisting of alcohol solution of metal alkoxide containing one kinds of oxide such as Si applied and burnt on one of inner and outer faces of a front panel and setting the thickness of the film properly in connection with refractive index. CONSTITUTION:A transparent glass thin film 3 whose main content is SiO2 is fit to be formed by applying and thermally forming alcohol solution of alkoxide of Si on the surface (whichever inner face or outer face) of the front panel 2 of a cathode-ray tube 1. The refractive index of the thin film 3 is 1.45 and glass refractive index of the panel 2 is 1.53, then reflection preventing effect can be obtained. And optical thickness (nd) of the thin film 3 is controlled to 1/4lambda0 (lambda0: light wave length, n: refractive index). Instead of Si, any of Mg, Th, Ce, Al, Ti, Zr, La, Pr, Sb, Nd and Zn can be used in alcohol solution of alkoxide.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a cathode ray tube, which is coated with an anti-reflection coating to prevent images from becoming difficult to read due to external light reflected by a front spring. .

[Background of the invention]

Conventionally, such anti-reflection films have been formed using vapor phase methods using vacuum, such as vacuum evaporation and sputtering.
Anti-Reflection Coating (
It has been put into practical use under common names such as A-coat (abbreviated as A-coat).

However, such a method FilO−・IQ Torr
Mass production of busy and large products such as cathode ray tube panels requires a huge amount of equipment management, which limits production quantity and increases costs, so it is used only for high-end products. In addition, the mechanical and chemical strength of the vapor-deposited film is weak, and sufficient care must be taken when handling it, resulting in a short lifespan and insufficient reliability.

Regarding such conventional AR coatings, for example, see Hiroshi Kubota, "Wave Optics J, February 2, 1971, published by Iwanami Shoten," Yoshifumi Katsube, "About Multilayer Coatings for Lenses."
Optical technology] Familiar with VoAi, 9° No. 8, etc.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its object is to provide a cathode ray tube that can be mass-produced at low cost and has excellent anti-reflection effects and reliability.

[Summary of the invention]

In order to achieve such an objective, the cathode ray tube of the present invention has antireflection %-qMy, 84, Th, Ce, Al
, Ti, Zr, La, Pr, Sb, Nd, Zrz7) oxides have a low refractive index, and the wavelength of light to prevent n1 reflection is set to be combined in the λ0 range.

[Embodiments of the invention]

Next, the present invention will be explained in detail using the drawings.

In the figure, 1 is a cathode ray tube, and antireflection films 3 and 4 are formed on the inner and outer surfaces of a front panel 2, respectively. Further, reference numeral 5 denotes a fluorescent material layer coated further inside the antireflection film 3 formed on the inner surface of the front panel 2. Both anti-reflection groups 3.4 are applied so as to cover at least the effective surface of the front panel, but it is not necessarily necessary to provide them on both surfaces of the front panel as in the illustrated example.
A sufficient antireflection effect can be obtained on either the inner or outer surface.

However, since it is not possible to coat the inner surface of the cathode ray tube in its completed state, the material must be temporarily attached and assembled into the cathode ray tube when it is a member. At that time, there is a possibility of damage due to various mechanical and chemical treatments during the manufacturing process, which increases the usage ratio of the parts and increases costs. Therefore, it is usually applied to the outer surface.

The antireflection film 3.4 is formed, for example, as follows. First, to explain an example of the simplest one-layer structure, the surface of the front panel of Braun-Wl (inner or outer surface may be used) contains Si alkoxide, which is necessary for M-silicate, or has a chemical formula of 84 ( An alcohol solution (containing water and an acid catalyst j − ) of (R represents an alkyl group such as C2Hs) is applied by a swivel or dipping. Next, by calcining this at 150 to 200°C for 10 to 60 minutes, hydrolysis and polymerization reactions occur due to the action of moisture in the air, water added in advance, and an acid catalyst, and 5ki2 is mainly A thin film of transparent glass as a component is firmly adhered. This thin film has a refractive index of 1.45, and since the refractive index of the glass constituting the front panel 2 of the cathode ray tube 1 is 1.53, it exhibits an antireflection effect.

Here, since the reflectance is the lowest when the wavelength of light is λ01 and the refractive index of the above thin film is, the thickness of the coating film is controlled so as to satisfy this relationship. For example, in the example mentioned above, λo=
If 0.55 μm, n = 1.45 to d = 0.09
/Jm.

Note that instead of 8i, Mf and Th are used as metal components.

Ce, Al, Ti, Zr, La, Pr, 8b
, Nd 2 , Zn t7) may be used to form a thin film containing an oxide of these metals. In addition, 2$J of Si and the above metals
A mixed solution containing the above may be used to form a film containing two or more of these oxides.

In general, the film is not limited to one layer, but may be formed by laminating two or three or more films containing one or more oxides of Si or metal components as described above in a predetermined order. ,
The antireflection effect can be further improved. In this case, by appropriately selecting the optical thickness of each layer, the antireflection effect can be further improved.

Note that by heating the front panel to 40 to 80° C. before applying the alcohol solution, it is possible to accelerate the hydrolysis and polymerization reactions and further increase the adhesion strength of the film.

Next, a specific example will be explained.

Solutions A-D were prepared containing starting materials as shown in Table 1. By applying these solutions to the surface of the front panel of the Bulawan tube with a spinner and baking them, or by layering films made of other solutions, it is possible to collect various types of transparent metal oxides as normal reflected light. Since the wavelength range of the light in question is 0.45 to 0.65 μm, we considered antireflection effects targeting light with a central component wavelength of 0.55 μm, but the reflectance is small over the entire wavelength range. Since this is a case of multiple layers, it is more advantageous to use a multilayer film than a single layer film.

〔Effect of the invention〕

As explained above, according to the present invention, the 0Mv, 81. Th, Ce,
AA! , Ti, Zr, La, Pr, Sb, Na, Zn
By providing an anti-reflection film containing at least one oxide of It is possible to eliminate the difficulty in seeing. In addition, the antireflection film according to the present invention does not require a complicated and expensive vacuum deposition process when forming it, and has extremely high film strength, resulting in cost reduction and high reliability. has advantages.

[Brief explanation of drawings]

The figure is a partially sectional front view showing an example of a weave according to the present invention. 1-Fist: Braun tube, 2: Battle, front panel, 3.4
...Anti-reflection film, 5...Writing fluorescent substance layer.

Claims (1)

[Claims] Mg, Si,
Th, Ce, Al, Ti, Zr, La, Pr, Sb, N
d, at least one layer is formed by applying and thermally baking an alcohol solution of a metal alkoxide containing at least one kind of oxide of Zn, and the thickness d of the film is the refractive index of the film n
, the wavelength of the light whose reflection is to be prevented is λ_0, and the optical film thickness nd is from (1/16)λ_0 to (1/2)λ_
A cathode ray tube characterized in that each layer is set to be combined in a range of 0.