JPS63138636A - Color picture tube - Google Patents

Abstract

PURPOSE:To aim at improvement in color purity, by forming a crystalline thin film, having a function intercepting light at a wavelength other than the vicinity of each color luminous peak of red, green and blue, between a black coating to be formed in a clearance part of each color phosphor of red, green and blue and a phosphor layer in a panel inner surface. CONSTITUTION:In order to check reflection of the whole faceplate to an inner surface of a panel 4 and improve the extent of a contrast, there is formed with a black coating 2 except a part forming a phosphor layer 1 in the inner surface of the panel 4. Afterward, a crystalline thin film of magnesium fluoride or the like is formed in a first color phosphor coating scheduled position via a mask pattern upon adjusting a spectral transmission factor so as to meet a luminous peak of a phosphor in the first color. After this thin film interference filter 3 is formed, likewise the thin film interference filter 3 is formed in each phosphor coating scheduled position of the second color and the third color in order upon adjusting the spectral transmission factor, and each phosphor of red, green and blue is applied thereon, forming the phosphor layer 1. With this constitution, each color purity of red, green and blue is improved without any adverse effect, and coloration to the panel and, what is more, color expressive ability is improvable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Object of the Invention) (Field of Industrial Application) The present invention relates to a color picture tube, and more particularly to a phosphor screen thereof.

(Prior art) In general, a color picture tube has a substantially rectangular panel as shown in Fig. 3), a funnel-shaped funnel (c), and a neck.
A vacuum envelope is constructed from the following. A phosphor 8a) is formed on the inner surface of the panel, and an electron beam ■
An electron gun 0 that emits . In a color picture tube, for example, as shown in Fig. 2, a striped phosphor layer ω is formed on the inner surface of the panel, and these phosphors are, for example, 450 n1ll (blue) and 535 n
It has luminescence peaks near 1ll (green) and 6250m (red), and white light is obtained by combining the luminescence of these three colors.

In order to absorb the emission in the red, green, and blue overlapping regions of the emission spectra of these phosphors and improve color purity, we have developed a phosphor with excellent selective absorbance between the peaks of the phosphor emission spectrum (λ-574 nm). Some use panel glass containing neodymium oxide (NdzO3) (eg, 586 nm).

However, the selective light absorption of the panel glass containing Nd2O3 also acts on the light reflected from the fluorescent screen of external light, which has the disadvantage that the panel surface exhibits a bluish-green color, causing a sensation of strangeness.

(Problems to be Solved by the Invention) Since the conventional Nd2O3 glass panel itself has selective light absorption, it has the disadvantage of coloring the panel.

SUMMARY OF THE INVENTION An object of the present invention is to provide a phosphor screen that improves the color purity of red, green, and blue and improves color expression ability without having the above-mentioned drawbacks.

[Structure of the invention]

(Means for Solving the Problems) The present invention has been made to solve the above problems. Color purity can be improved by forming a crystalline thin film between the body layers that blocks light at wavelengths other than those near the emission peaks of red, green, and blue colors.

(Function) When each of the red, green, and blue phosphors is excited by an electron beam and emits light, it has a transmission spectrum centered around the emission peak of each emission color provided between the black film on the inner surface of the panel and the phosphor layer. Due to the effect of the crystalline thin film (thin film interference filter), the spectrum that falls between the peaks of each emission color is absorbed, resulting in emission colors with extremely high color purity.

Furthermore, since the panel itself uses panel glass that has flat transmission characteristics for wavelengths in the visible @ range, unlike panels containing NdzOa, the panel does not appear colored due to reflection of external light.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a main part of a panel showing an embodiment of the present invention.

In Figure 1, first of all, in order to suppress reflections on the entire surface of the screen and improve contrast,
(on the panel) A black film (■) is formed on the inner surface of the panel except for the area where the phosphor layer will be formed. After that, a crystalline thin film such as magnesium fluoride (hereinafter referred to as MQFz) is placed on the first color phosphor target position through a mask pattern, and the spectral transmittance is adjusted to match the emission peak of the first color phosphor. About 1000
It is formed to have a thickness of nm. After forming this thin film interference filter (2), thin film interference filters are formed in the same manner at the positions where the second and third color phosphors are to be deposited by adjusting the spectral transmittance. Thereafter, red, green, and blue color phosphors are applied to form a phosphor layer (2).

To explain in more detail, when forming the thin film interference filter 〇, first of all red, green, and blue phosphors, M
2.Adjust the film thickness. At this time, the positions where the other two colors of phosphors are applied are masked so that the MQF2 film does not come into contact with them, for example, by placing a shadow mask (2) and a similar structure close to the inner surface of the panel.

Similarly, for the second and third colors, thin film interference filters (2) are formed so as to have spectral transmittances centered around the respective emission peaks. The center wavelength of spectral transmittance and spectral characteristics can be adjusted arbitrarily by changing the film thickness of M(jF2).

For example, the film thickness at the planned bottom formation position of the blue phosphor having an emission peak of 450 nm is 900 ol II, 5
The filter film thickness at the fixed position of the green phosphor mouth former having an emission peak of 35 nm is 1,100 mm, and the filter film thickness at the position where the red phosphor having an emission peak of 625 nm is planned to be formed is 1,300 mm.

By forming a phosphor screen using such a method, it is possible to provide a screen with excellent color purity.

Further, the material of the crystalline thin film is not limited to MgFz, but it goes without saying that a similar effect can be obtained if a crystalline substance such as zinc sulfide (ZnS) is used.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to improve the color purity of each color of red, green, and blue, and to improve color expression ability, without the disadvantage of coloring the panel.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view of the main part of a color picture tube panel showing an embodiment of the present invention, Fig. 2 is a schematic sectional view of the main part of a conventional panel, and Fig. 3 shows the configuration of a color picture tube Q tube. It is a schematic sectional view. ■...phosphor layer ■...black film■...
・Thin film interference filter (a)...Panel ■...Shadow mask 0...Electron gun■...Electron beam agent Patent attorney Nori Chika Nori Yudo Norio Ogoi) Beaml Zudai 1 Figure 1) Pi'-4 Myodai 2 Kuo

Claims (1)

[Claims] A phosphor layer formed on the inner surface of the panel, a black film formed in the gap between the phosphor layers, and a shadow mask with a large number of through holes arranged close to and opposite to the phosphor layer. and an electron gun that emits an electron beam that causes the phosphors in the phosphor layer to selectively emit light through the shadow mask, in which each phosphor is provided between at least the phosphor layer and the inner surface of the panel. 1. A color picture tube characterized by having a crystalline thin film having a spectral transmittance with a center wavelength at an emission peak of .