JPS6346950B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a television image projection image using an enlarged projection method (it does not matter whether the viewer selects a reflected image or a transmitted image of the image formed on the screen). Regarding the improvement of the cathode ray tube for projection that constitutes the source, in particular, it is important to improve the properties of the cathode ray tube itself by improving optical precision, to reduce the manufacturing process and parts by rationally simplifying the structure, and to improve the overall quality of the cathode ray tube. The purpose of this is to make the equipment unnecessary and inexpensive. A typical conventional example of this type of projection cathode ray tube is disclosed in Japanese Patent Application Laid-open No. 52232/1983. Figure 1 shows
A cross-sectional view of the main parts is shown for an overview. Such a projection cathode ray tube is usually made of glass and comprises a funnel part 2 connected to a neck part 1 equipped with a single electron gun and a deflection coil, a face plate 3, and a tapered cylindrical part 4 connecting the two. A vacuum container 10 , a target 11 sealed and fixed in the container, a concave mirror 12, a support frame 13 for them, and a heat dissipating metal (cylindrical) 1 integrated with the target surface.
4, etc., and normally a Schmitt plate 15 is disposed in front of the face plate. In such a conventional example, via the support frame 13,
Before sealing the vacuum container 10 , the target and the concave mirror must be supported and fixed with considerable precision at the center of the electron beam or at the optical center of the image to be imaged on the target surface. This has become a bottleneck in improving precision, eliminating the need for equipment adjustments, reducing processes, and reducing parts. The present invention aims to improve the drawbacks of such conventional examples. As one such improvement, a structure in which a metal such as aluminum is vapor-deposited on the inner surface of the funnel portion having a curvature similar to that of a concave mirror, and the vapor-deposited surface is made into a Schmitt mirror (that is, equivalent to the concave mirror 12 described above) is as follows. This 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 with which the target surface is fixed in the vacuum container, and it cannot be said that the optical accuracy has been sufficiently improved. In view of this, the face plate 23 with the target surface 22 formed on the central metal mounting surface is made of convex glass of equal thickness, as shown in FIG. 2 as a side view of the main part and as shown in FIG. 3 as an exploded perspective view. At the same time, by arranging the center of curvature to coincide with the center of curvature O of the funnel portion 24, a so-called spherical seat is formed. , 26 may also be ground and polished so that they have the same curvature as the face plate 23, and the face plate 23 may be sealed with welded glass or the like while it is in contact with the open end surface in its normal direction. . With such a configuration, even if the face plate 23 is slightly shifted and comes into contact with the open end surface of the cylindrical housing 25, the face plate 23 will still
Therefore, the concave mirror 27 formed by the target surface and the inner surface of the funnel forms a spherical seat, and the center of curvature of both remains at point O, so the accuracy of the optical system is not affected. However, in such an example, variations in the thickness of the fused glass, that is, the thickness of the bonding layer between the face plate and the open end surface, affect optical accuracy and cause a decrease in manufacturing yield. Even when welding the part 24 or sealing the funnel part 24 and the cylindrical casing, it is essential to pay close attention to the welding thickness, which has become a bottleneck in reducing process steps. Also, anode 29 and anode terminal 3
Since the anode lead 31 connecting 0 was suspended in the vacuum container, great care was required during manufacturing and handling. The present invention has been made in view of the various drawbacks of the conventional examples. The details are shown below in Fig. 4, which shows a partially exploded perspective view of one embodiment, Fig. 5, which shows a vertical cross-sectional view of the center of the rigid metal casing, and Fig. 5, which shows the center of the case in which the face plate and the neck portion are fixed to the casing. This will be explained with reference to FIG. 6 showing a longitudinal cross-sectional view, FIGS. 7A and 7B showing an enlarged view of the main part of FIG. 6, and FIG. 8 showing a method of adjusting the mounting position. The projection cathode ray tube of the present invention is roughly divided into a rigid metal casing 50 forming a funnel part 51 and a cylindrical part 52, a face plate 60 made of convex glass of equal thickness, a neck tube 70 and a Schmitt plate 80. However, the configurations of the network tube 70 and the Schmitt plate 80 are the same as the conventional ones, except that the former is equipped with a high-brightness type electron gun and the structure for attaching it to the funnel part. Since this goes beyond the gist of the invention, the explanation will be omitted. The rigid metal casing 50 has an inner surface in the shape of a concave reflecting mirror, and by vapor-depositing chromium or aluminum on the inner surface, the rigid metal casing 50 has a spherical seat configuration that shares the center of curvature with the face plate 60 as a concave mirror 53. A method may be adopted in which the concave mirror 53 is made integral with or separate from the cylindrical portion 52 and sealed and welded before rough polishing of the concave mirror 53. 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 depositing chrome, aluminum, or the like. As will be described later, the rigid metal casing 50 is conductively connected to a metal layer 62 such as aluminum deposited on the lower layer of the target surface 61, that is, on the center of the inner surface (convex surface) of the face plate, and serves as an anode lead wire. Therefore, except for the part where the lead wire with the anode cap 90 for high pressure supply is connected, use Teflon (tetrafluoroethylene), silicone rubber, or 1-
2. Cover with insulating resin such as polybutadiene. The temperature coefficients of the rigid metal casing 50 and the face plate 60 are substantially the same, and it is necessary that even if they expand due to the ambient temperature and the temperature generated from the inside, it does not particularly affect the sealing parts, etc. . In order to improve the connection accuracy between the neck tube 70 and the funnel portion 53 of the rigid metal casing 50 , a stem 100 as shown in the sectional view of the main part in FIG. 7A is used. The stem 100 can be a rigid metal body made of a so-called 42-6 alloy of Cr: 42% by weight, Ni: 6% by weight, and Fe (remainder), and basically the bottom outer surface 101
has a double cylindrical shape with a bottom and is molded to the same curvature so as to be in close contact with the outer surface of the funnel part 51, and one of the two inner and outer cylindrical parts 102 and 103 (inner in the embodiment) On the inner surface of the cylindrical portion 102, at least three protrusions 104 are provided at equal intervals (120° intervals) for positioning the neck tube 70.
104 is integrally provided. In order to secure the stem 100 to the opening 54 of the funnel portion 51 of the rigid metal cylinder 50 with high precision, a jig 110 as shown in FIG. 8 is used. This jig 110 includes the funnel portion 51
A funnel part inner surface abutting part 111 forming a part of a spherical surface based on the center of curvature of the cylinder part 112 having an outer diameter approximately equal to the inner diameter of the cylindrical part 52, and the inner surface of the cylinder part and the funnel part 51. The rigid metal casing 50 may be made of aluminum die-casting and is integrally provided with a stem positioning cylinder 113 having an outer diameter equal to the inner diameter of the stem 100 and centered on a line connecting the center of the concave mirror to be formed and the center of curvature O.
Then, the stem 100 is accurately positioned and fixed as shown in FIG. By welding or brazing the stem 100 in this fixed state, the protrusions 104, 1 of the stem 100 can be fixed.
04, etc., and hold the inner diameter end 71 of the open end of the neck tube 70, which has been accurately cut on a plane perpendicular to the center of the tube, on the stem 100.
The neck tube 70 can be fixed to the funnel portion 51 with a predetermined accuracy by holding it in contact with the bottom portion 105 of the tube, oxidizing it in a wet hydrogen furnace, and then fixing it with a sealing glass such as frit glass. When the stem is oxidized in advance and welded to the funnel part, it is essential to take care to prevent the oxide film from being affected by the welding heat. A separate collar ring 120 is used to ensure that the joining and sealing of the face plate 60 and the face plate 60 are not affected by the thickness of the adhesive such as frit glass. The collar ring 120 is made of Ni-Cr
- A cylindrical part 121, which can be made of Fe-based rigid metal, has an inner diameter equal to the outer diameter of the cylindrical part 52, and a cylindrical part 121 extending outward with a taper substantially parallel to the tangential direction of the peripheral edge of the face plate 60 . It consists of a skirt portion 122 and at least three protrusions 123, 123 arranged on the skirt portion at approximately equal intervals. The height of the protrusion is determined so that the sealant (for example, the fritted glass 124) interposed between the skirt portion 122 and the face plate 60 has sufficient bonding and fixing ability and can withstand shearing force. If the skirt portion 122 is not provided with the protrusion 123, the desired optical precision cannot be obtained unless the face plate 60 and the skirt portion 122 are in precise contact with each other on the entire circumference, so the skirt portion 122 must be polished. Although processing becomes difficult, in the present invention, since at least three protrusions 123 are provided on the skirt portion 122, the protrusions 12
Optical precision can be easily achieved by simply polishing 3. As described above, the face plate 60 shares the center of curvature with the concave mirror 53 formed on the inner surface of the funnel portion 51, so the inner surface of the funnel portion 51 is polished (ground if necessary) around the center of curvature O, and the protrusions are polished. If the tips of the parts 123, 123 are also polished (ground), even if the contact between the tips 123 of each protrusion and the convex surface of the face plate 60 is misaligned, they form spherical seats, so there is no possibility that the optical precision will be distorted. do not have. A metal anode surface is deposited on the central part of the inner surface of the face plate made of glass of equal thickness whose curvature has been determined as described above, and the desired red, blue, and
Or, a hard-to-saturate phosphor that emits edge light is evenly coated. One end of the vapor-deposited metal is
It has a cross-sectional area (particularly width) capable of withstanding high pressure, extends to the periphery of the face plate 60 , and is configured to abut on one or more protrusions provided on the skirt portion of the collar ring 120, thereby functioning as an anode lead wire. Configure as appropriate. As mentioned above, the protrusion 123,1
23 and the peripheral edge of the face plate 60 are in contact with each other, the flange ring 120 fixedly sealed to the rigid metal housing 50 and the face plate 60 are melt-sealed with fritted glass or the like, and placed inside the housing container. By vacuuming, it is possible to realize a projection image pickup tube with consistent optical accuracy. In addition, the position where high pressure is supplied via the anode cap 90 can be set at any position in the rigid metal casing 50 , and X-ray radiation, which should be taken care of in high-intensity cathode ray tubes, can be shielded considerably. Furthermore,
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 perspective view, Fig. 5 is a longitudinal sectional view of a portion, Fig. 6 is a longitudinal sectional view of the main part, Fig. 7 A is a sectional view of the neck tube sealing part, and Fig. 7 B is a sectional view of the face plate sealing part. FIG. 8 is a cross-sectional view of the main part in the process of aligning and attaching the stem to the funnel part. 50 ...Rigid metal casing, 100 ...Stem, 70 ...
Neck tube, 120 ... collar ring, 60 ... face plate.

Claims (1)

[Claims] 1. A casing including a cylindrical part with an open end and a funnel part made of rigid metal, and a curvature of the inner surface of the funnel part that abuts a sealing means provided at the open end of the cylindrical part at the periphery and also serves as a concave mirror. a face plate made of glass of equal thickness so as to have a center of curvature that coincides with the center, and a target surface provided approximately in the center; and a face plate provided with an electronic pigeon and formed of an insulating tube around the opening on the back side of the funnel part. a neck portion fixed by a stem, and the inner peripheral edge of the face plate is positioned in contact with the sealing means at the open end of the cylindrical portion, and the two are sealed together, and the sealing means is a cylindrical portion whose inner diameter is equal to the outer diameter of the cylindrical portion; a skirt portion extending outward with a taper substantially parallel to the tangential direction of the peripheral edge of the face plate; and at least three cylindrical portions arranged at approximately equal intervals on the skirt portion. The stem has a double cylindrical shape with a bottom and is molded to the same curvature so as to closely fit the outer surface of the funnel, and has two inner and outer cylindrical parts. A projection cathode ray tube characterized in that the inner surface of one of the cylindrical parts is integrally provided with at least three protrusions for positioning the neck part at equal intervals.