JPS62271330A - Beam index type cathode-ray tube - Google Patents

Abstract

PURPOSE:To achieve better color reproducibility as well as simplification of the manufacturing process, by arranging a light guidance plate in front of a bulb face, collecting the index light from index stripes through the front of the bulb face and also, receiving the light from the side of the bulb face. CONSTITUTION:By irradiation of electron beams L to a phosphor screen 22 through a metal back layer 23, respective color lights are emitted from phosphor strips R, G and B through a light guidance plate 24. By incidence of an index light from an index stripe I on the light guidance plate 24, either direct light or indirect light refrected by the metal back layer 23, a phosphor material 26 is excited and its wavelength is converted, and the wavelength converted index light L' radiates isotropically, therefore a part of it directly propagats to a peripheral end face where a photo sensor is arranged, and another part propagats to a peripheral end face where the photo sensor 25 is arranged, reflecting at the end face or front and back faces of the light guidance plate. Based on the index light L' detected by the photo sensor 25, the RGB signals are switched and the color picture reproduction is carried out.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention The present invention relates to a beam index type cathode ray tube.

The color image reproduction method in conventional color TV receivers is as follows:
The common method is the shadow mask method, in which an electron gun for red, green, and blue is housed inside a color cathode ray tube, and color discrimination is performed using a shadow mask. The beam index method, which reproduces each color of blue, has been attracting attention and prizes because it has superior features such as power reduction and brightness compared to the shadow mask method.

The operating principle of the beam index type color cathode ray tube will be explained with reference to FIG. The cathode ray tube shown in the same figure (
In 1), (2) is the bulb, (3) and (4) are the fluorescent film and metal back layer formed on the inner surface of the face (2a) of the bulb (2), and (5) is the bulb (2). It is one electron gun housed in the neck (2b). The phosphor film (3) is composed of a large number of phosphor stripes in a vertical stripe pattern, and the phosphor stripes are, for example, composed of a series of phosphor stripes (R) (G) (B) in three colors of red, green, and blue. One index stripe (I) for emitting index signal is arranged for every triple left (T).

An electron beam (L) from an electron gun (5) is scanned on the phosphor film (3) in a direction perpendicular to the phosphor stripes (R), (G), and (B). The electron beam scanning position at this time is detected by an optical sensor (6) that detects index light (L') emitted from the index stripe (I) by irradiation with the electron beam (L). The index signal output from the sensor (6) is sent to the index processing circuit (7), and the signal from the index processing circuit (7) causes the color I/rI conversion circuit (8) to be The RGB signals from the electron gun (
5) to reproduce the color image.

A specific example of a beam index type color cathode ray tube based on the above operating principle will be described with reference to FIGS. 4 and 5. The same reference numerals as in FIG. 3 indicate the same parts, and the explanation thereof will be omitted. Fluorescence y! formed on the inner surface of the face (2a) of the bulb (2) in this cathode ray tube (1)! (3) consists of a large number of phosphor stripes, for example, 1 consists of a series of phosphor stripes (R), (G), and (B) in three colors of red, green, and blue.
One index stripe (1) is arranged for each triple left (T). The above index stripe (1
) is 1 tri-blend on metal back layer (4) (T)
It is formed by aligning each. Further, the optical sensor (6) is provided in a part of the funnel (2c) of the bulb (2),
A light guide (9) is arranged on the outer peripheral surface of the funnel (2c) to efficiently capture the index light (L') from the index stripe (1). Light guide (
9) is a band-shaped material in which a fluorescent substance such as Rhodamine 6G (trade name) is dispersed in a transparent resin such as acrylic resin or epoxy resin, and the optical sensor (9) is attached to one end of the band.
6) is located.

When the electron beam (L) irradiated from the electron gun (5) is scanned, the index light (J) generated from the index stripe (1) is transmitted to the light guide (
The main surface (9a) having a sufficiently larger area than the light receiving surface of one of the optical sensors (6) of 9) is irradiated with light. Then, as shown by the solid arrow, the index light (L゛) is inserted into the light guide (9).
is introduced, and when this excites the fluorescent substance (10), index light (L'') with a longer wavelength than the incident index light (L'') is generated.This fluorescent substance (10) causes e-length conversion. index light ([,
“) radiates in all directions 1, and a part of it propagates directly to the end surface (9c) side where the optical sensor (not shown) is arranged, and other than the critical angle θC that causes total reflection. Light with a large incident angle does not leak outside and is totally reflected at the main surface (9a) (9b) or other end surface, and this is repeatedly propagated to the end surface (9c).This light guide (9) The larger the refractive index n2 of the constituent transparent resin is compared to the refractive index n1 of air, the more
Even if the incident angle θi of the index predecessor ゛) is large, it can efficiently enter the light guide (9) and excite the fluorescent substance (10) efficiently, and the critical angle θC can be small. Index light (
L') can be totally reflected and guided to the end face (9c) at a high rate of 9JJ (see Japanese Patent Laid-Open No. 121664/1983).

Next, another specific example of a beam index type color cathode ray tube will be described with reference to FIGS. 6 to 9. In the cathode ray tube (10) shown in the figure, (11) is a flat bulb, (12) is a fluorescent film, (13) is an electron gun, and (14) is a flat bulb.
is an optical sensor, and (15) is a light guide. Valve (11)
is a flat container in which fluorescent light (%<12) is formed on the inner surface of the back surface (11b) facing the face (11a), and a light guide (15) is arranged on the outer surface. A neck (11G) is integrally connected to the face (11a) and the back surface (llb), and an electron gun (13) is housed in the neck (11G). Fluorescence III (12) consists of a large number of phosphor stripes (R) (G) (B), a series of three color phosphor stripes (R) (G) (B)
One index stripe (I) is arranged in the same row for every tribut (T) consisting of the following. Graphite (16) is applied to the interface between the phosphor stripes (R) (G) (B) and the back surface (11b) for the purpose of increasing contrast and preventing charge-up on the phosphor screen. The light guide plate (15) is located on the back side (11) of the bulb (11).
b) It has a seedling on the outer surface thereof which is substantially flush with the fluorescent film (12), and the index light from the index stripe (1) is incident on the entire surface thereof. The incident index light is condensed on the end face side of the light guide (9), and the light sensor (14) arranged on the outer periphery of the light guide (15)
detected by.

By the way, in the conventional beam index type color cathode ray tube mentioned above, in the case of the bulb (2) in Fig. 4, the optical sensor (6) is placed in the funnel (2c) and bare light is emitted from the rear surface. Therefore, phosphor stripes (R) (G) (B),
Metal back layer (4), index stripe (I
), and in this case, it is difficult to align the phosphor stripes (R), (G), and (B) with the index stripes ([). Furthermore, since the solid angle when viewing the light guide (9) from one point of the index stripe (I) is small, the utilization rate of the index light (L'') is low.

Further, in order to make the electric field distribution uniform, although not shown, an opaque 4-electric film made of graphite or the like is formed on the inner surface of the funnel (2c). It is necessary to open a window for the light-receiving window in this opaque conductive film, and in addition, it is necessary to form a transparent conductive film or a mesh-like conductive film in the window part to make the window conductive. It was quite complicated.

Next, in the bulbs (11) shown in FIGS. 6 to 9, since images are viewed from above, it is not possible to form a metal bank layer on the fluorescent film (12). Therefore, the electron beam (L)
is irradiated, the fluorescent film (12) is charged up, and the brightness is reduced.

Therefore, a transparent conductive film for discharging the negative charges may be formed on the fluorescent HJ (12), but this increases the number of steps and costs. Furthermore, since there is no metal bank layer, a reflection effect cannot be obtained and the index light incident on the light guide (15) becomes weak.

The present invention was proposed in view of the above-mentioned problems, and the technical means to solve this problem is to provide fluorescence emitting light in three primary colors on the inner surface of the bulb face. Body stripes and index 76
A cathode Ijt tube in which index stripes emitting numbers are repeatedly formed in a predetermined arrangement, and the face i
a light guide plate disposed on the il side, in which a fluorescent substance for wavelength converting the index light is dispersed, and a light guide plate fixed to the outer periphery of the light guide plate to detect the index light propagated within the light guide plate toward the outer periphery. It consists of an optical sensor.

According to the beam index type cathode ray tube according to the present invention,
A light guide plate is placed in front of the valve face, and the index light from the inch-thickness drive is received from the front side of the valve face and from the side.

General ■ A first embodiment of the present invention will be described below with reference to figure f51. In the cathode ray tube (20) shown in the figure, (21) is the bulb, (22) and (23) are the fluorescent film and metal back layer laminated on the inner surface of the face (21a) of the bulb (21), (24) (25) is a light guide plate (described later) disposed in front of the face (2]a), and (25) is a light sensor fixed to the outer periphery of the light guide plate (24). The phosphor film (22) is composed of a large number of phosphor stripes, and each phosphor stripe is composed of one triple left (R) (G) (B) consisting of a series of phosphor stripes (R) (G) (B) of three colors, for example, red, clear, and blue. One index stripe N) is arranged in the same row for each T). The light guide plate (24) is a transparent plate made of a suitable resin such as acrylic resin or epoxy resin and a fluorescent substance (26) is dispersed therein, as in the past.
It has approximately the same rectangular size as a) and is fluorescent! (
26) There is a light guide plate (26) that converts the wavelength of the index light from the index stripe (I), such as Rhodamine 6G (trade name).
4) A filter (not shown) for cutting off ultraviolet light from the outside is installed in front.

The optical sensor (25) may be directly fixed to the outer periphery of the end surface of the light guide plate (24), or may be indirectly connected by an optical fiber, for example, a PIN photodiode. At this time, a reflective film may be provided on the other end face of the light guide plate (24) to increase the light receiving efficiency.

When scanning the electron beam from the electron gun (27), the electron beam (
When the phosphor stripe (R) (G
) (B) is filtered through the light guide plate (24) to emit light in each color.

Then, when the index light from the index stripe (1) enters the light guide plate (24) either directly or after being reflected from the metal back 5 (23), it excites the fluorescent substance ff1 (2G) and wavelength converted. The index light (Lo) whose wavelength has been converted by this fluorescent material 'R (26) is radiated uniformly, and a part of it propagates directly to the outer peripheral edge where the optical sensor (25) is arranged.
The other part is the light guide plate (24) due to the above-mentioned reason shown in Fig. 4.
The light propagates toward the outer peripheral end surface of the optical sensor (25) while being reflected from the end surface or front and rear surfaces of the optical sensor (25). After this, the RGB signals are switched based on the index light (Lo) detected by the sensor (25), and color image reproduction is performed.The index light has a longer wavelength due to the fluorescent substance (26) in the light guide plate (24). The light is converted into light and enters the optical sensor (25), but
In general, when using an optical sensor that has low sensitivity near ultraviolet light and peak sensitivity near infrared light, it can receive light with high sensitivity.

Next, a second embodiment in which the present invention is applied to a two-index type color cathode ray tube will be described with reference to FIG. This two-index type color cathode ray tube reproduces an appropriate color image by detecting two types of index lights and combining them into one index signal. Therefore, the difference from the first embodiment is that the cathode ray tube (20'
) Fluorescence formed on the inner surface of the face (21a) of the pulp (21)! ! ! ! (28) and the above pulp (2
1) and a light guide plate (29) disposed in front of the light guide plate (29).

That is, the phosphor film (28) has a large number of phosphor stripes of different emission colors, for example, phosphor stripes (R) of three primary colors of red, green and blue containing index fluorescent pairs (G+
One index stripe (1) is arranged for every triple left (T) consisting of I) (B).

When this fluorescent film (2B) is irradiated with an electron beam, a phosphor stripe containing an index phosphor (G+1) and an index stripe containing only an index path light material (1) are used.
), two types of index lights are generated.

On the other hand, the light guide plate (29) is formed by overlapping a first light guide plate (30) and a second light guide plate (31), and each of the first and second light guide plates (30) (31) is Similar to the light guide plate (24) in the first embodiment, a fluorescent substance (32
) (33) is dispersed, and the face (21
It has approximately the same rectangular size as a). In the first light guide plate (30), during electron beam irradiation, the phosphor stripe (
Index light (Ll') emitted from G+1)
The second light guide plate (31) converts the index light (L2) emitted from the index stripe (1) into
') to wavelength conversion. The first and second light guide plates (30)
First and second optical sensors (34) and (35) for detecting the two types of index light (Ll'> (L2°)) are respectively fixed on the outer peripheral portions of (31), for example, on the upper and lower end surfaces. , if necessary, on the front of the light guide plate (29),
A filter (not shown) is placed to cut off ultraviolet light from the outside.

When the phosphor film (28) is scanned with the electron beam (L) irradiated from the electron gun (27), the index light (Llo) emitted from the phosphor stripe (G+1) is the same as in the first embodiment. The index light (L2°) emitted from the index stripe (1) passes through the first light guide plate (30) and enters the second light guide plate (31). . The index light (Ll'') incident on the first light guide plate (30) excites the fluorescent substance (32) in the first light guide plate (30) and undergoes wavelength conversion. Index light (Lr'
) propagates within the first light guide plate (30) toward the outer periphery, and a portion thereof reaches the first optical sensor (34). Also, the index light (L
! ) is also wavelength-converted in the same manner as described above and reaches the optical sensor (35) of ff12. In this way, one index signal obtained by combining the two types of index lights (L1'') (L2') detected by the first and second optical sensors (34) (35) is used to generate an RGB signal. Color image playback is performed by switching sequentially.

According to the present invention, there is no need to stack and align the phosphor stripes and the index stripes, and moreover, the index light emitted backward from the index stripes is reflected by the metal back layer and the light guide plate Since the index light is incident on the
.

There is no need to form a window on the opaque conductive film on the inner surface of the annular panel, which simplifies the process.In addition, the negative charges accumulated in the fluorescent film are discharged from the metal back layer, improving brightness and achieving high color reproducibility. We can provide quality color cathode ray tubes.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of a beam index type cathode ray tube according to the invention, and FIG. 2 is a sectional view showing a second embodiment of the invention. Fig. 3 is a sectional view showing the operating principle of a beam index type cathode ray tube, Fig. 4 is a sectional view showing a specific example of a conventional beam index type cathode ray tube, and Fig. 5 is a light guide of the cathode ray tube of Fig. 4. 6 to 9 are cross-sectional views showing other specific examples of the conventional beam index type cathode ray tube. (20) (20') -m- cathode ray tube, (21a
) -11-Face, (24) (29)--Light guide plate, (25) (
34) (35) - Optical sensor, (R) (G) (B) -
Phosphor stripe, (■) - index stripe. Patent applicant: Kansai NEC Co., Ltd.
Rijin Gangwon Province I 3rd figure 4th figure 5,',s /6 //Rice ゛15
Figure 5 Figure 8 Please note Figure 9

Claims (1)

[Claims] (1) A color cathode ray tube in which phosphor stripes emitting three primary colors and index stripes emitting index signals are repeatedly formed in a predetermined arrangement on the inner surface of the bulb face; A beam index type cathode ray tube comprising: a light guide plate in which a fluorescent substance is dispersed; and a sensor fixed to the outer periphery of the light guide plate and detecting an index signal propagated inside the light guide plate toward the outer periphery.