JPH0721997B2 - Cathode ray tube - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a structure of a cathode ray tube using a glass envelope, and more particularly to a glass thickness distribution of the envelope.

[Technical background of the invention and its problems]

In a conventional cathode ray tube, an envelope is composed of a panel having a rectangular outer shape and a phosphor screen on the inner surface thereof, and a funnel extending to the panel and a neck having an electron gun therein.

In such a cathode ray tube, the panel has a curved surface bulged outward in order to make the distance to each part of the screen scanning surface as equal as possible, starting from the deflection center of the electron beam from the electron gun.

However, at present, a cathode ray tube designed to flatten a face plate of a glass panel as much as possible to give a most visually pleasing impression is proposed in US Pat. No. 4.537.921. In addition, such a cathode ray tube is widely used for television receivers and computer terminals,
It is the mainstream of cathode ray tubes.

At the same time, active research is being carried out in various fields on the flattening of cathode ray tubes, and various methods have been proposed for a long time, but the reliability of the glass envelope in terms of vacuum strength is also a major obstacle, and it is currently commercialized. There are few things I did.

Therefore, the whole system as a cathode ray tube has not changed from the old one, and the one with a wider deflection angle of the electron beam, for example, the one with 110 ° deflection is now widely used as a short full-length tube with a shortened depth of the cathode ray tube. It's being used. Recently, there has been a demand from the market for a cathode ray tube in which the face plate of the panel is further flattened, and at the same time the deflection angle of the electron beam is further widened.

Increasing the radius of curvature of the face plate of the cathode ray tube panel to make the face plate flatter, and at the same time to achieve a wide deflection angle, a problem is to keep the mechanical strength of the glass envelope sufficient. To properly select the glass envelope structure, that is, the glass wall thickness in each part of the envelope.

Generally, as a condition for maintaining sufficient mechanical strength in a glass envelope, when the actual product is made, the stress against atmospheric pressure in each part of the envelope, so-called vacuum stress is 1200 PSI (pound square inc).
h) It has long been known experimentally and empirically that the following is necessary.

As described above, increasing the panel thickness is the most effective in reinforcing the stress of a panel having a face plate with a large radius of curvature, and even in the case of a current face plate with a large radius of curvature, The reinforcement is carried out by the method. Further, at this time, it is also practiced to increase the glass wall thickness of the inner surface near the connecting portion with the skirt portion around the face plate where the simultaneous vacuum stress concentrates.

Further, the reinforcement against the vacuum stress due to the widening of the deflection angle is also carried out by increasing the glass thickness.

However, if the faceplate radius of curvature of the panel is 30
When the flatness exceeds 00 mm and the flatness is good, or the deflection angle is
An ultra-wide-angle deflection cathode ray tube having an angle of more than 110 ° has a significantly different envelope shape than a normal cathode ray tube, and the distribution of vacuum stress is also significantly different from that of a conventional cathode ray tube. These are a sudden increase in vacuum stress in the peripheral portion of the face plate due to an increase in the radius of curvature of the face plate of the panel, and a concentration of vacuum stress due to the occurrence of a sudden shape change portion of the envelope for realizing the ultra-wide-angle deflection, Another major cause is the change in the distribution of vacuum stress in the skirt that accompanies the shortening of the skirt to achieve ultra-wide-angle deflection.

Reinforcement against vacuum stress as described above can also be reinforced by increasing the glass thickness of each part, but if the glass thickness of each part is simply reinforced according to a conventional reinforcing method, the excessive glass thickness of the face plate will be reduced. This increases the weight of the envelope and the cost, which is not preferable in practice.

[Object of the Invention]

It is an object of the present invention to provide a cathode ray tube having a face plate with extremely good flatness, a total length of the cathode ray tube being shortened, and excellent mechanical strength.

[Outline of Invention]

According to the present invention, a face plate having a substantially spherical shape protruding in the tube axis direction and having a substantially rectangular planar shape, and a skirt extending from a peripheral portion of the face plate in a direction opposite to the protruding direction and substantially in parallel with the tube axis. And a second envelope having a main surface extending in a direction transverse to the tube axis and having a peripheral edge connected to the skirt. In the provided cathode ray tube, the thickness of the skirt in the communicating portion with the second envelope is 1.3 times or more the thickness in the central portion of the face plate, and the length of the diagonal line of the rectangular portion of the face plate. The cathode ray tube is characterized in that the height of the first envelope in the tube axis direction is eight times or more.

The diagonal length of the rectangular portion of the face plate is the first
25 times or less of the height of the envelope in the tube axis direction.

Example of Invention

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is an example (including a partial sectional view) of an example of a cathode ray tube according to the present invention. Here, in the cathode ray tube of FIG. 1, all internal structures are omitted to simplify the description. Also, the description of the internal structure is omitted.

The cathode ray tube (1) has a phosphor screen on its inner surface and has a substantially spherical shape protruding in the tube axis direction, and a face plate (2) having a substantially rectangular planar shape, and the protrusion from the peripheral portion of the face plate. A first envelope (4) having a skirt (3) extending parallel to the tube axis in the opposite direction, and a peripheral edge connected to the skirt having a major surface extending transversely to the tube axis. It is composed of a funnel portion (5) and a neck portion (6) which is an extension of the funnel portion (5) and has an electron gun therein. The first envelope (4) is generally called the panel (4). Further, in this description, the funnel portion (5) and the neck portion (6) are collectively referred to as the second envelope (7).

The phosphor screen applied to the inner surface of the face plate (2) of the cathode ray tube (1) of the embodiment has a width of 406.4 mm,
It has a height of 304.8 mm and an effective diameter diagonal of 508.0 mm, and has a screen effective diameter equivalent to 20 inches.

It is a super wide-angle deflection cathode ray tube in which the deflection angle of the electron beam is 115 °.

The radius of curvature of the outer surface of the face plate (2) is 3500 mm.
Is a single spherical curved surface, and has much better flatness than the face plate of the conventional cathode ray tube. The radius of curvature of the inner surface of the face plate (2) is 2700 mm.

FIG. 2 shows a cross-sectional view of the long side of the face plate (2) of the first envelope (or panel) (4), and FIG. 3 shows a conventional effective screen having the same effective diameter as the present embodiment. The cross-sectional view of the long side portion of the face plate (8) of the cathode ray tube is shown.

The first envelope (or panel) of the conventional cathode ray tube of FIG.
The radius of curvature of the outer surface of the face plate (8) of (10) is 17
It is a single spherical curved surface of 50 mm, the inner surface has a curvature of 1350 mm, and is used for a cathode ray tube with a deflection angle of 90 °.

The panel (4) of the embodiment shown in FIG. 2 has a seal edge portion (11).
3rd because the funnel (5) for 115 ° deflection is connected at
The height of the skirt portion (3) is shortened as compared with the conventional example shown in the figure. This is to prevent a sudden change in the shape of the funnel (5) due to wide-angle deflection, and the panel (10) in FIG.
When a funnel with 5 ° deflection is formed, the seal edge (1
It is impractical because the funnel shape in the vicinity of 2) has to change suddenly and the vacuum stress concentrates on the part where the shape changes rapidly.

The height PH1 of the conventional first envelope shown in FIG. 3 is 85 mm, and the height PH2 of the first envelope of this embodiment shown in FIG. 2 is 65 mm, which is 20 mm shorter than the conventional example. is there.

As for the shape of the skirt portions (3) and (9), the glass wall thickness becomes smaller toward the seal edge portions (11) and (12) in both the embodiment and the conventional example.

FIG. 4 is a schematic diagram for explaining the vacuum stress distribution of the cathode ray tube envelope, and is a cross-sectional view in the X-axis direction (long side direction) of the cathode ray tube of FIG. 1, in which vacuum stress is most likely to be concentrated. The place.

In a normal cathode ray tube, the vacuum stress concentrates in the section (B) in FIG. 4, so that the vacuum stress is reinforced mainly in the section (B). In the case of a 90 ° -deflecting cathode ray tube, there are a method of increasing the glass thickness of the section (A) of the face plate (2) and a method of increasing the glass thickness of the inner surface of the section (B).
Either one or both are performed at the same time to increase the mechanical strength. When the radius of curvature of the face plate (2) is slightly increased, the vacuum stress in the section (B) is increased and at the same time, the stress distribution in the section (C) is affected.

In this case, it is possible to reinforce all against the vacuum stress only by reinforcing the section (A) and the section (B), but if the radius of curvature of the face plate (2) is remarkably increased and the flatness of the face plate (2) becomes extremely good, a vacuum is generated. The stress also increases sharply instead of the above-mentioned slight increase, and a considerable amount of glass wall thickness must be increased to reinforce the stress. At the same time, the influence in the section (C) also remarkably increases. It is also necessary to increase the wall thickness.

The method of increasing the glass thickness of the face plate (2) is the most effective for the above reinforcement, and only this method can deal with all the increase of the vacuum stress due to the increase of the curvature radius of the face plate (2). However, since it is necessary to consider the increase in the weight and cost of the entire envelope, it is not practical to reinforce by only this method.

Further, it is physically or mechanically possible to cope with the reinforcement against the curvature increase of the face plate (2) only by increasing the glass thickness of only the skirt portion (3) without increasing the glass thickness of the face plate (2). However, there is a limit in terms of the thickness, and the increase in the glass thickness of the face plate (2) and the skirt portion (3) must be properly selected and reinforced.

Here, as in the embodiment of FIG. 2, when the radius of curvature of the face plate (2) increases and the deflection angle also becomes wider, the vacuum stress when the height PH2 of the skirt portion is shortened is from the funnel portion (5). Vacuum stress and face plate (2)
The vacuum stress is distributed over the entire skirt part (3), the peripheral part of the face plate and the vicinity of the seal edge part (11) of the funnel (5), and the reinforcement against this vacuum stress is applied to the sections (A) (B) ( C) It is necessary to increase the glass thickness of the entire area.

The present invention will be described below with reference to specific examples.

FIGS. 5 and 6 show the results of calculation analysis of the vacuum stress distribution based on the finite element method of the cathode ray tubes of the conventional example and the present example having the first envelope of FIGS. 3 and 2.

(A) (B) (C) (D) in FIGS. 5 and 6 correspond to the sections (A) (B) (C) (D) in FIG. 4, respectively.
Further, FIGS. 5 and 6 show only the calculation result of the portion where the vacuum stress is most concentrated in the X-axis direction (long side direction) from the calculation result of the vacuum stress of the entire envelope. The left end corresponds to the center of the face plate, and the position corresponding to the neck along the surface of the envelope is expressed in order below.
The side represents the tensile stress, and the one side represents the compressive stress. 5 and 6 each show a radial stress component from the center of the face plate, that is, a stress component perpendicular to the seal edge, and this stress component is a numerical value representing the mechanical strength of the envelope.

As is apparent from FIG. 5, in the conventional cathode ray tube, the glass wall thickness in the section (C), that is, near the seal edge (12) is 9.2 m.
Despite m, no large vacuum stress is applied to the section (C). Further, in this embodiment shown in FIG. 6, although the glass thickness of the seal edge portion (11) is 17.5 mm, the vacuum stress more than that in the conventional example is applied to the section (C).

Therefore, the reinforcement of the mechanical strength of the cathode ray tube envelope in which the radius of curvature of the face plate is extremely large and the deflection angle is further widened, in addition to the reinforcement method used in the conventional cathode ray tube, It is clear that increasing the glass wall thickness is also an important method.

7 and 8 show changes in the vacuum stress distribution with changes in the height of the skirt. FIG. 7 shows a conventional 110 ° -deflecting cathode ray tube, and FIG. 8 shows the vacuum stress distribution of a cathode ray tube with a shortened skirt at the same time along the shape of the envelope. The line extending to the outside of represents the strength of the vacuum stress. As is clear from FIGS. 7 and 8, when the length of the skirt part is shortened, the vacuum stress near the seal edge part (arrow in the figure) increases significantly, and a considerable amount of reinforcement near the seal edge is required. It turns out that

FIG. 9 shows the calculation result of the vacuum stress of the seal edge portion in the X-axis direction with respect to the height of the first envelope, that is, the length of the skirt portion. This calculation is based on a conventional cathode ray tube envelope having a screen having a diagonal effective diameter of 20 inches (508 mm) as a reference model, and the height of the first envelope is changed. .

Further, the height of the first envelope is standardized by the diagonal effective diameter of the screen, and its value is K1.

(K1 = effective diagonal diameter [mm] / height of envelope [mm]) As is clear from Fig. 9, when the value of K1 exceeds 8, the vacuum stress value at the seal edge exceeds 1000 PSI, It can be seen that the sealing edge portion also needs to be reinforced by increasing the glass thickness.

FIG. 10 shows the calculation result of the vacuum stress at the seal edge portion in the X-axis direction with respect to the glass wall thickness at the seal edge portion of the skirt. This calculation result is also based on the same model as the calculation model shown in FIG. Further, the glass wall thickness of the seal edge portion is standardized by the glass wall thickness of the central portion of the face plate (8), and the value is set to K2.

(K2 = seal edge wall thickness [mm] / face plate wall thickness [mm]) Also, the vacuum stress at the seal edge part of a conventional cathode ray tube is 80.
It is about 0 PSI, and by relating this value to FIG. 10, it can be seen that when the value of K1 is 8 or more, K2 must be at least 1.3 or more.

Therefore, the reinforcement of the mechanical strength of the cathode ray tube having the envelope in which the height K1 of the first envelope exceeds 8 is the conventional method for increasing the inner wall thickness of the skirt face plate side. In addition, it is necessary to increase the glass thickness of the entire skirt including the seal edge and the second envelope in the vicinity of the seal edge so that K2 is at least 1.3 or more.

In addition to the above conditions, when the radius of curvature of the face plate becomes larger, the glass thickness of the face plate is increased and at the same time, the value of K2 is set to 1.3 or more to minimize the increase in the glass thickness of the entire envelope. Thus, a cathode ray tube envelope having excellent mechanical strength can be constructed.

However, if the value of K1 is set to a remarkably large value, it is necessary to remarkably increase the glass thickness of the entire envelope to reinforce the structure of the envelope, resulting in an increase in the weight and cost of the envelope and also in manufacturing. It becomes extremely difficult, and at the same time, the area of the peripheral part (ineffective screen part of the face plate) increases as the value of K2 increases, which is not preferable in terms of visual perception and space. Therefore, the value of K1 is 25 or less in practice. It is desirable to set to.

In the description of the above embodiment, the conventional cathode ray tube whose effective diameter of the screen is 20 inches has been described as the reference model, but also in other cathode rays having different screen effective diameters, K1 and K2.
By setting the above value so as to satisfy the above condition, the increase in the glass thickness of the entire envelope can be minimized, and a cathode ray tube envelope having excellent mechanical strength can be constructed.

In recent years, active studies on flattening of cathode ray tubes have been made, and JP-A-60
A large number of cathode ray tubes having an envelope as proposed in Japanese Patent Publication No. 89041 are disclosed. In order to realize such a flat cathode ray tube, the flatness of the face plate must be extremely good and the height of the skirt must be shorter than that of the conventional cathode ray tube. The overall shape of the container is also symmetrical about the seal edge. Therefore, the vacuum stress from both the first envelope on the face plate side and the second envelope on the back surface side is likely to concentrate on the skirt portion and the entire region in the vicinity thereof. Therefore, the vacuum stress must be dealt with by the same method as that of the embodiment shown in FIG.

FIG. 11 shows a half sectional view of the envelope in the X-axis direction (long-side direction) of the flat cathode ray tube and the calculation result of the vacuum stress distribution.
The envelope of Fig. 11 has a face plate with a radius of curvature of 5000 mm.
It has a shape with extremely good flatness. Also, in this case, the seal edge part has a shape in which the first and second envelopes are almost symmetrical, so the value of K1 is 14.5 and the value of K2 is 2.0 with the symmetrical surface as the seal edge part. is there.

In the vacuum stress distribution, a line extending to the outside of the surface of the envelope represents the strength of the vacuum stress, as in FIGS. 7 and 8. The maximum value is 1100 PSI, which is the element indicated by the arrow in FIG.

For flat cathode ray tubes with short skirts and extremely good face plate flatness, as shown in Fig. 11, especially the relationship between the glass thickness of the face plate and the glass thickness of the entire skirt (K2) is appropriate. If this is not set, the weight of the envelope will be significantly increased, which is not practically preferable, and the value of K2 should be as large as possible within the range in which the first and second envelopes can be connected at the seal edge. It is desirable to set the value.

The height of the first envelope referred to in the present invention is the distance in the tube axis direction between the seal edge portion that substantially connects the first envelope and the second envelope to the outer surface of the central portion of the face plate. is there. Therefore, for example, as shown in FIG. 12, in an envelope having a step in the tube axis direction at least at a part of the seal edge portion, a portion (A) of the stepped portion which is the farthest from the face plate (a portion closest to the face plate). The central portion (C) of B) is defined as a substantial seal edge portion, and the distance (PH3) in the tube axial direction between the substantial seal edge portion (C) and the outer surface of the central portion of the face plate is the first outer circumference. The height of the vessel.

Similarly, the distance between the inner surface and the outer surface in the seal edge portion referred to in the present invention is substantially the surface closest to the pipe axis in the seal edge portion that connects the first envelope and the second envelope. It is the distance between the surfaces away from the tube axis.

It is apparent that the present invention is extremely effective as a reinforcing method against vacuum stress even in an envelope of a cathode ray tube having a plurality of small electron gun sections as proposed in Japanese Patent Application No. 60-97901.

The distance between the inner surface and the outer surface of the seal edge portion referred to in the present invention is because a groove or the like is provided in the seal edge portion. Therefore, when there is a gap in the seal edge portion, the surface of the seal edge portion closest to the pipe axis and the pipe It is the distance from the surface away from the axis.

In the present embodiment, the shape of the face plate, that is, the shape of the phosphor screen has been described as a substantially rectangular shape having long sides and short sides. However, a cathode ray tube having a phosphor screen in which the long side and the short side are substantially equal in length. Also in the above, it is possible to reinforce against the vacuum stress by the same method as in this embodiment. In this case, as described in the above embodiment, it is necessary to reinforce the face plate substantially centrally in the vicinity of the center of each side instead of reinforcing the center in the vicinity of the center of the long side.

The glass thickness of the seal edge portion referred to in the description of the present embodiment is the distance between the inner surface and the outer surface of the seal edge portion, and the glass thickness of the face plate is the distance between the inner surface and the outer surface of the face plate. It is the distance.

〔The invention's effect〕

As described above, according to the present invention, the flatness of the face plate is much better than that of the conventional cathode ray tube, and in the cathode ray tube having a very large deflection angle, the glass wall thickness of the skirt portion is different from the face panel wall thickness. With proper selection, the weight increase of the envelope can be minimized as compared with the conventional tube, and a cathode ray tube having excellent mechanical strength can be provided.

In addition, even in a flat cathode ray tube where the flatness of the face plate is extremely good and the length of the skirt part is short, the glass thickness of the entire skirt part is appropriately increased as described above to easily provide excellent mechanical strength and a lightweight flat shape. A cathode ray tube can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view (including a partial cross-sectional view) of a cathode ray tube according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a long side portion of a face plate of a first envelope. FIG. 4 is an enlarged cross-sectional view of the long side of the face plate of the cathode ray tube. FIG. 4 is a schematic diagram for explaining the vacuum stress distribution of the envelope of the cathode ray tube. FIG. 5 is the calculation result of the vacuum stress distribution of the conventional cathode ray tube. FIG. 6 is a diagram showing the calculation result of the vacuum stress distribution of the cathode ray tube of the present embodiment, and FIG. 7 is a sectional view of the conventional cathode ray tube and a diagram showing the vacuum stress distribution. Is a cross-sectional view of a cathode ray tube with a short skirt and a diagram showing the vacuum stress distribution. Fig. 9 is a diagram showing the change in the vacuum stress at the seal edge with the length of the skirt. Fig. 11 is a diagram showing the change in vacuum stress at the seal edge with respect to the glass thickness at the edge. The FIG. 12 the seal edge portion is a diagram showing the cross-sectional view and a vacuum stress distribution of the flat type cathode ray tube is a cross-sectional view of a cathode ray tube having a step. 1 ... Cathode ray tube 2 ... Face plate 3 ... Skirt part 4 ... First envelope (panel) 5 ... Funnel part 6 ... Neck part 7 ... Second envelope

Claims (2)

[Claims] 1. A face plate having a substantially spherical shape projecting in the tube axis direction and having a substantially rectangular planar shape, and a face plate substantially parallel to the tube axis in a direction opposite to the projecting direction from the peripheral edge portion of the face plate. A glass having a first envelope formed of an extending skirt and a second envelope having a main surface extending in a direction transverse to the tube axis and having a peripheral edge connected to the skirt, the inside of which is evacuated. In the cathode ray tube including the valve, the wall thickness of the skirt connected to the second envelope is 1.3 times or more the wall thickness of the central portion of the face plate, and the thickness of the diagonal line of the rectangular portion of the face plate is First length
A cathode ray tube having a height of 8 times or more the height of the envelope in the tube axis direction. 2. The length of a diagonal line of the rectangular portion of the face plate is 25 times or less the height of the first envelope in the tube axis direction. Cathode ray tube.