JPS597730Y2 - Cathode ray tube for projection - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the improvement of a projection cathode ray tube for use as an enlarged projection type television image projection image source, and in particular, to improving the performance of the cathode ray tube itself by improving optical precision. The purpose of this invention is to reduce the manufacturing process and parts by rationally simplifying the structure, as well as to eliminate the need for adjustments and to reduce the overall cost of the device.

A typical conventional example of this type of cathode ray tube for projection is
-52232.

FIG. 1 shows a sectional view of the main parts for an overview.

A cathode ray tube for projection projection is usually equipped with a single electron gun and has a vacuum tube made of glass, consisting of a funnel part 2 connected to a neck part 1 on which a deflection coil is attached, a face plate 3, and a tapered cylindrical part 5 connecting the two. It consists of a container 10, a target 11 sealed and fixed in the container, a concave mirror 12, a support frame 13 for them, a heat dissipating metal (cylindrical) 14 integrated with the target surface, etc. A Schmidt plate 20 is arranged.

In the conventional example, the target and the concave mirror 12 are moved through the support frame 13 before the vacuum container 10 is sealed, so that the center of the electron beam or the latter is the optical center of the image to be imaged on the target plane. It must be supported and fixed with considerable precision, improving optical precision and eliminating the need for device adjustments.
This had become a bottleneck in reducing process and parts.

The present invention is intended to improve these drawbacks of the prior art.

As a further improvement, a metal such as aluminum is vapor-deposited on the inner surface of the funnel part, which has a curvature similar to that of a concave mirror, and the vapor-deposited surface is made into a Schmidt mirror (that is, equivalent to the concave mirror 12 described above). , has already been proposed by the same applicant as the present case (Japanese Patent Application Laid-Open No. 53-21523).

However, even in such a case, the optical accuracy is largely dependent on the accuracy of fixing the target surface in the vacuum container, and it cannot be said that the optical accuracy has been sufficiently improved.

In view of this, a face plate I.30 with a target surface 32 formed on the central metal vapor deposition surface 31 was constructed, as shown in FIG. 2 as a side view of the main part and as shown in FIG. 3 as an exploded perspective view. It is formed of thick convex glass and is arranged so that its center of curvature coincides with the center of curvature O of the inner surface of the funnel part 40 to form a so-called spherical seat. The open end surfaces 42, 42 of the casing 41 are also ground and polished to have the same curvature as the face plate 30, and the face plate 30 is sealed with welded glass or the like with the face plate 30 in contact with the open end surface in its normal direction. Another possible method is to do so.

With such a structure, even if the face plate 30 is slightly shifted and comes into contact with the open end surface of the cylindrical housing 41, the face plate 30 and therefore the target surface 32 will still be affected.
Since the concave mirror 43 whose funnel inner surface is shaped like a spherical seat and whose center of curvature is still at point O,
It does not affect the accuracy of the optical system.

However, in such an example, variations in the thickness of the welded glass, that is, the thickness Δg of the bonding layer between the face plate and the open end surface, affect the optical accuracy and cause a decrease in manufacturing yield. Even in the case of welding 40 or sealing between the funnel portion 40 and the cylindrical housing 41, it is essential to pay close attention to the welding thickness Δl, which has become a bottleneck in saving process steps.

Further, the connecting lead wire 45 between the anode 31 and the anode terminal 44 is suspended in the container, which is a bottleneck in automating manufacturing or handling the cathode ray tube.

The present invention was devised in view of the various drawbacks of the conventional examples.

The details are shown below in Fig. 4 showing a partially exploded perspective view of one embodiment, Fig. 5 showing a longitudinal cross-sectional view of the center of the rigid metal casing, and Fig. 5 showing the center of the state in which the face plate and neck portion are fixed to such a casing. While referring to FIG. 6 showing a longitudinal sectional view, FIG. 7 showing an exploded perspective view of FIG. 6, FIG. 8 showing a method of adjusting the mounting position, and FIG. 9 showing a sectional view of a different embodiment, Explain the details of the idea.

The projection cathode ray tube of the present invention can be roughly divided into funnel portion 6
1 and a cylindrical portion 62; a face plate formed of convex glass of equal thickness; a neck tube 80; and a Schmidt plate 90; and Simulate Play 1.90
The structure of the former is the same as the conventional one except for the fact that it is equipped with a high-brightness type electron gun and the mounting structure of the funnel part, and the explanation thereof will be omitted since it is outside the gist of the present invention.

The rigid metal casing 60 has a concave reflecting mirror shape on which chrome or aluminum is vapor-deposited on its inner surface, and has a spherical seat structure that shares the center of curvature with the face plate 70 as a concave mirror, and has a cylindrical portion. It is also possible to adopt a method in which it is integrated with 62 or separate from it and is sealed and welded after polishing the face plate surface.

The inner surface of the funnel portion may be mirror-polished around the center of curvature to form a concave mirror, thereby increasing the precision of the curvature, thereby omitting the step of vapor deposition of chromium, aluminum, or the like.

As will be described later, the rigid metal housing 60 has a target surface 7.
1, that is, the metal layer anode 72 deposited on the inner surface (convex surface) of the face plate, and functions as an anode lead wire. The parts except for the connecting parts are covered with an insulating resin such as Teflon (tetrafluoroethylene), silicone rubber, or 1-2 pobutadiene.

It is necessary that the temperature coefficients of the rigid metal-connected housing 60 and the face plate 70 are substantially the same, so that even if they expand due to the ambient temperature and the temperature generated from the inside, the sealing portions and the like are not particularly affected.

A stem 100 is used to improve the connection accuracy between the neck tube 80 provided with the high-intensity electron gun 81 and the funnel portion 61 of the rigid metal housing 60.

The stem 100 includes Cr: 42% by weight, Ni: 6
A rigid metal body made of so-called 42-6 alloy with weight% Fe (remainder) can be used, and basically it is shaped to have the same curvature so that the bottom outer surface 101 is in close contact with the outer surface of the funnel section 61. The neck tube 80 has a double cylindrical shape at the bottom, and is provided with neck tubes 80 on the inner surface of one of the two inner and outer cylindrical portions 102 and 103 (inner in the embodiment) at at least three locations (120° intervals). protrusion 104 for positioning
, 104 are integrally provided.

Opening 64 of the funnel portion 61 of the rigid metal cylinder 60
In order to dry the stem 100 with high precision, the eighth
A jig 110 as shown in the figure is used.

This accommodation device 110 includes a funnel portion inner surface abutting portion 111 based on the center of curvature of the funnel portion 61, and a cylindrical portion 6.
The stem 10
Stem positioning cylinder 1 with an outer diameter equal to an inner diameter of 0
The rigid metal housing 60 and the stem 100 are accurately positioned and fixed as shown in FIG. 8.

By welding or brazing the stem 100 in such a fixed state, the neck tube 80 can be fixed with the protrusions 104, 104, etc. of the stem 100.
At the same time, the inner diameter end 82 of the open end of the neck tube 80, which has been accurately cut on a plane perpendicular to the tube center, is held in contact with the bottom 105 of the stem 100, and the inner diameter end 82 of the neck tube 80 is held in contact with the bottom 105 of the stem 100. If the neck tube 80 is oxidized and then fixed with a sealing glass such as frit glass, the neck tube 80 can be fixed to the funnel part 61 with a predetermined precision.

When the stem 100 is oxidized in advance and welded to the funnel portion 61, care must be taken to prevent the oxide film from being affected by the heat of fusion.

The contact between the lower surface of the bottom of the stem and the funnel part 61 does not have to be a surface contact, but may be a point contact at three or more points, or a line contact structure.

On the other hand, joining the cylindrical portion 62 and the face plate 70,
A separate collar ring 120 is used to ensure that the sealing is not affected by the thickness of the adhesive such as frit glass.

The collar ring 120 may be made of Ni-Cr-Fe-based rigid metal, and has a cylindrical portion 121 whose inner diameter is equal to the outer diameter of the cylindrical portion 62, and is substantially parallel to the tangential direction of the peripheral edge of the face plate 70. a skirt portion 1 that extends outward with a tapered shape;
22 and at least three protrusions 123 arranged at approximately equal intervals on the skirt portion.

The height of the protruding portion is determined so that the sealing agent (for example, the frit glass 130) interposed between the skirt portion 122 and the face plate 70 has sufficient bonding ability and can withstand shearing force. .

The face plate 70 has the funnel portion 6 as described above.
Since the center of curvature is the same as that of the concave mirror 65 formed on the inner surface of the curved wheel 65, the funnel portion 61
Along with polishing the inner surface (grinding if necessary), the protrusion 12
3. If the tips of 123 are also polished (grinded), each protrusion 1
Even if the convex surfaces of the face plate 23 and the face plate 70 come into contact with each other out of alignment, the optical accuracy will not be affected because they each form a spherical seat.

A metal anode surface is deposited on the central part of the inner surface of the face plate, which is made of glass of equal thickness and whose curvature is determined as described above, and a metal anode surface is deposited thereon to emit the desired red, blue, or green light. Saturable phosphor is evenly applied.

One end of the vapor-deposited metal has a cross-sectional area (particularly width) that can withstand high pressure, extends to the periphery of the face plate 1-70, and contacts one or more protrusions provided on the scar 1 portion of the flange ring 120. They are arranged so that they are in contact with each other and function as an anode lead wire.

The flange ring 120 may be formed integrally with the rigid metal casing 60, or, as shown in FIG. It is also possible to measure improvements in accuracy.

As described above, the flange ring 120 and the face plate 7 are fixedly sealed to the rigid metal casing 60 with the protrusions 123, 123 and the peripheral edge of the face plate 70 in contact with each other.
0 by melt-sealing with Flynn I glass or the like to create a vacuum inside the housing, it is possible to realize a cathode ray tube for projection without variations in optical precision.

In addition, the position at which high pressure is supplied via the anode cap 63 can be set at any position in the rigid metal housing 60, and X-ray radiation, which should be taken care of in high-intensity cathode ray tubes, can be shielded considerably.

According to the present invention as described above, it is possible to realize a projection cathode ray tube that is inexpensive and highly reliable without variations in optical accuracy.

[Brief explanation of the drawing]

1 and 2 are sectional views of main parts of different conventional examples, and FIG. 3 is an exploded perspective view of the conventional example shown in FIG. 2. 4 to 8 relate to the present invention, FIG. 4 is a partially exploded perspective view, FIG. 5 is a partial longitudinal sectional view, FIG. 6 is a longitudinal sectional view of the main part, and FIG. 7 is an exploded perspective view. , FIG. 8 is a diagram showing a method of positioning the stellate l in the funnel part, and FIG. 9 is a sectional view of a main part of a different embodiment. 60... Rigid metal casing, 80... Neck pipe, 70...
...Face plate, 100...Stem, 61...
・Funnel part.

Claims (1)

[Scope of utility model registration request] A double cylindrical structure in which a funnel part whose inner surface is a concave mirror and a cylindrical part following it are made of rigid metal, and a neck part holding an electron gun is connected at a bottom part along the outer slope of the funnel part. 1. A projection cathode ray tube, characterized in that the projection cathode ray tube is sealed via a stem having at least three neck tube positioning protrusions (including an annular one) inside the tube.