JPH057720Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(a) Industrial application field The present invention relates to a beam index type flat color cathode ray tube. (B) Prior art As is well known, a beam index type color cathode ray tube has an index phosphor stripe on the inner surface of the panel and three primary color phosphor stripes arranged in a certain relationship with the index phosphor stripe. A color image is reproduced by stimulating a desired color phosphor with a predetermined amount of electron beam using an index optical signal obtained when a single electron beam scans a phosphor screen provided with a phosphor screen. It was designed to do so. Flat color cathode ray tubes using such a beam index method were developed, for example, in the 1970s.
It is described in Publication No. 27864. The phosphor screen structure of the flat color cathode ray tube described in this publication has _{a P16} emission wavelength peak on the inner surface of the picture tube wall in the ultraviolet region.
An index phosphor is provided, a transparent conductive film (NESA film) with a quality that blocks ultraviolet rays is applied thereon, three primary color phosphors of red, green, and blue are provided on this transparent conductive film, and further the picture tube tube is provided with an index phosphor. A filter is installed on the outside of the wall to allow only ultraviolet rays to pass through. However, there is a problem in that it is actually difficult to provide a transparent conductive film formed on a phosphor screen such as the above-mentioned Nesa film with a quality that can completely block ultraviolet rays. (c) Problems that the invention aims to solve This invention was created in view of the above-mentioned drawbacks.
It is an object of the present invention to easily realize a flat color cathode ray tube having a structure capable of reproducing color images satisfactorily even under strong external light such as outdoors. (d) Means for solving the problem Index phosphor stripes repeatedly arranged on the inner surface of the first tube wall of the opposing first and second tube walls of the flat glass tube body, and the index phosphor stripes. a layer of non-luminescent material disposed between the stripes; a red layer repeatedly disposed on the non-luminescent material in regular relation to the index phosphor stripes;
A phosphor screen consisting of three primary color phosphor stripes of green and blue is formed, and when the phosphor screen is scanned with an electron beam, index light obtained from the index phosphor is placed on the outer surface side of the first tube wall. In a flat color cathode ray tube, the light is converted into light with a longer wavelength than the index light by a condenser plate and guided to a photoelectric conversion element, and the light emission of the three primary color phosphor stripes is observed from outside the second tube wall. A filter plate for blocking ultraviolet rays is disposed between the outer surface of the first tube wall and the light condensing plate, or at least one of the outer surface of the second tube wall. (e) Effect With the above configuration, the filter plate blocks ultraviolet light among the external light when used outdoors. (F) Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 8. FIG. 3 shows a cross-sectional structure of a beam index type flat color cathode ray tube and a part of its drive circuit. 1 is a flat glass tube body, and the tube body 1 is provided with an observation window 2. It consists of a fluorescent screen panel 4 having a fluorescent screen 5 formed on its inner surface, and a neck part 7 in which an electron gun 6 is housed. In the deflection coil, 10 indicates the central axis of the electron beam (the traveling direction of the electron beam when not deflected). FIG. 4 shows the cross-sectional structure of the phosphor screen 5 in detail, and the inner surface of the phosphor screen panel 4 is coated with a non-luminescent material layer 11 made of black carbon and a _P47 phosphor (Y An index phosphor stripe 12 made of ₂ SiO ₅ :Ce) is provided on the non-luminescent material layer 11, and in regular association with the index phosphor stripe 12, red (R),
Three primary color phosphor stripes of green (G) and blue (B) are formed, and a double layer of SiO ₂ and ITO is further formed to cover these index phosphor stripes 12, non-luminescent material layer 11, and three primary color phosphor stripes R, G, and B. A transparent protective film 13 is formed. Therefore, when the electron beam 10 scans the phosphor screen 5, the light emitted from the three primary color phosphor stripes R, G, and B is observed through the observation panel 3, while the index phosphor stripe 12 produces an emitted light. The light passes through the phosphor screen panel 4 and enters the condenser plate 14 (see Figure 3) arranged on the back side of the phosphor screen panel 4, where it is converted into a wavelength that matches the sensitivity of the light receiving element and is transmitted to the end surface. It is guided to a photodiode 15 arranged. As shown in FIG. 5, the light condensing plate 14 is a transparent flat plate made of synthetic resin doped with a fluorescent substance. 14 is preferably PMMA (polymethyl methacrylate), and the fluorescent material doped with it is Macrolex Fluorescent Yellow.
(Macro-Lex Fluorescent Yellow) 10GN is the best. Macrorex Full Arrest Yellow 10GN is a product name, and it is clear that it is a Cumasone-based material, and the composition has not been disclosed to consumers, but it is sold in the United States. “Dyeing and Colorist Association”
(The society of dyers and color lists), CISolvent Yellow−160
It is registered as a material, and the material is identified by this. The index signal converted into an electric signal by the photodiode 15 is supplied to an index signal processing circuit 16, which processes the three primary color video signals of R, G, and B obtained from the video signal processing circuit 17 based on the index signal. The color signals obtained are processed by the luminance and color signal processing circuit 18, and the output thereof is applied to the electron gun 6 so that the electron beam stimulates the desired color phosphor stripe with a predetermined beam amount. , whereby a color image is reproduced on the fluorescent screen 5. By the way, when such a flat color cathode ray tube is used outdoors under sunlight or strong lighting, external light passes through the index phosphor stripe 12 formed on the phosphor screen 5 and is concentrated. The outside light enters the light plate 14, undergoes wavelength conversion, and is guided to the photodiode 15, which lowers the S/N ratio of the index signal.As a result, the index signal cannot be detected and the image cannot be reproduced. This will lead to a situation like this. Therefore, the present invention has been devised as described below. That is, as can be seen from FIG. 6 showing the spectral transmission characteristics of the light collecting plate 14, the light collecting plate 14 has a wavelength of approximately 500 nm.
The glass that normally makes up the flat glass tube absorbs light with a wavelength of up to 500 nm or more, and transmits light with a wavelength of about 350 nm or more.
Since light with a wavelength of 350 nm or less is blocked, the light condensing plate 1
The wavelength range of light incident on 4 is approximately 350 ~
Consider light in the wavelength range of 500 nm. Therefore, as a first embodiment of the present invention, as shown in FIG. 7, we developed a light transmission wavelength characteristic [shown by a solid line] that substantially matches the emission wavelength characteristic [shown by the solid line] of the P ₄₇ (Y ₂ SiO ₅ :Ce) index phosphor. As shown in FIG. 1, an optical filter plate 19 having a shape (indicated by a broken line) is disposed between the outer surface of the fluorescent screen panel 4 of the flat glass tube 1 and the light condensing plate 14. In this embodiment, Fuji Filter SP14 (trade name) manufactured by Fuji Photo Film Co., Ltd. was used as the optical filter plate 19. If such an optical filter 19 is disposed between the outer surface of the fluorescent screen panel 4 of the flat glass tube 1 and the light condensing plate 14, the index signal can be suitably extracted. In addition, when the optical filter 19 is not arranged,
External light having a wavelength of 350 nm to 500 nm enters the light condensing plate 14 over the entire wavelength range, making it impossible to distinguish between the light emitted from the index phosphor stripe 12 and the external light, making it difficult to detect the index signal. This results in the inconvenience of not being able to do so. This is the index phosphor stripe 12
Although the external light passing through is weak and attenuated by the stripe 12, the intensity is approximately uniform in the range of 350 nm to 500 nm, so the overall emission energy is greater than that of the index phosphor stripe. be. In addition, external light that matches the characteristics of the filter 19 is
The light passes through the filter 19 and enters the light condensing plate 14.

[Table] (g) Effects of the invention According to the invention, a beam index type flat color cathode ray tube is provided which can reproduce images suitably even under strong external light such as outdoors. obtain.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of one embodiment of a flat color cathode ray tube of the present invention, FIG. 2 is a sectional view of a main part of another embodiment, and FIG. 3 is a beam index type flat color cathode ray tube. Figure 4 is a cross-sectional view of the tube and a part of its drive circuit; Figure 4 is a cross-sectional view taken along line A-A';
The figure is a perspective view of the light condensing plate, FIG. 6 is a diagram showing its spectral transmission characteristics, FIG. 7 is a diagram for explaining the first embodiment of the present invention, and FIG. 8 is a diagram showing the second embodiment of the present invention. FIG. 3 is a diagram for explaining an example. 1... Flat glass tube body, 3... Observation panel (second tube wall), 4... Fluorescent screen panel (first tube wall),
5... Fluorescent screen, 11... Non-emissive material layer, 12... Index phosphor stripe, 14... Light condensing plate,
15...Photodiode (photoelectric conversion element), 1
9, 20...Optical filter plate, R, G, B...
Three primary color phosphor stripes.

Claims (1)

[Scope of utility model claims] Index phosphor stripes repeatedly arranged on the inner surface of the first tube wall of the opposing first and second tube walls of the flat glass tube body, and a non-luminescent material layer arranged between the index phosphor stripes. , red repeatedly disposed on the non-luminescent material in regular association with the index phosphor stripes;
A phosphor screen consisting of three primary color phosphor stripes of green and blue is formed, and when the phosphor screen is scanned with an electron beam, index light obtained from the index phosphor is placed on the outer surface side of the first tube wall. In a flat color cathode ray tube, the light is converted into light with a longer wavelength than the index light by a condenser plate and guided to a photoelectric conversion element, and the light emission of the three primary color phosphor stripes is observed from outside the second tube wall. , wherein a filter plate for blocking ultraviolet rays having light transmission wavelength characteristics substantially matching the emission wavelength characteristics of the index phosphor is disposed between the outer surface of the first tube wall and the light condensing plate. type color cathode ray tube.