JPS5816586B2 - color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color picture tube, and more particularly to a color picture tube having color selection electrodes.

A color picture tube with color selection electrodes, such as a shadow mask type color picture tube, usually has an envelope formed by a panel made of glass and a funnel, and the inner surface of the panel has red dots or slots. A phosphor screen is formed by phosphors of three colors, green and blue, and a T shadow mask is incorporated opposite to the phosphor screen, and the phosphors of each color are made to emit light within the neck of the funnel. An electron gun that emits three electron beams λ is sealed, and the inside of the envelope is kept in a high vacuum. During operation, the three electron beams emitted from the electron gun are By scanning with a deflection yoke arranged around the periphery, the phosphors of each year are selectively emitted through the pores of the shadow mask, thereby reproducing a color image.

FIG. 1 shows the cross-sectional structure of a color picture tube for rice seeds.

That is, in this Figure 1, 1 is a panel, 2 is a funnel, 3 is an electron gun, 4 is a phosphor screen on the inner surface of panel 1, 5 is a pin embedded in the skirt part of panel 1, and l is this This is a shadow mask detachably supported by pins 5.

The shadow mask 7 is generally made of thin cold-rolled steel and has a large number of dots or slot-like pores formed therein, and when the aperture mask 7 is fixed, it has a thickness of about 1 to 2 rIrIrL. a frame 8 made of cold-rolled steel; a plurality of bimetals 9 having one end fixed to the frame 8 in order to correct color shift due to thermal expansion; and the pin 5 fixed to the other end of the bimetal 9 a spring 1 that is removably engaged with the spring 1;
It consists of 0.

In the conventional shadow mask type color picture tube configured as shown in FIG.
The electron beams emitted from the shadow mask pass through the pores formed in the aperture mask 7 of the shadow mask and cause the phosphor screen 4 to emit light as described above. Approximately 70% of the light is blocked by the aperture mask 7 and frame 8 that make up the shadow mask, and as a result, the shadow mask expands thermally, causing the following phenomenon. .

That is, as shown in FIG. 2, the aperture mask 7 is (7-
The position is shown in a), but after the operation starts, the result of thermal expansion appears in the aperture mask 7, which has a small heat capacity, and swells as shown in (7-b), causing the frame 8 to swell. Thermal expansion gradually begins, and at the same time bimetallic 9
It also gradually begins to curve.

Since the bimetal 9 is arranged so that the shadow mask 6 approaches the phosphor screen 4 due to its curvature, the aperture mask 7 is affected by the thermal expansion of the frame 8 and the curvature of the bimetal 9. It is added and spring-moved in the direction shown by the arrow 11.

It has been confirmed that although the initial thermal expansion of the aperture mask 7 reaches saturation in about 10 minutes, the thermal expansion of the frame 8 requires about one period of time to reach saturation.

Furthermore, in the movement caused by the thermal expansion of the shadow mask as described above, if we now pay attention to one pore of the aperture mask 7, the one pore that existed at point a in FIG. The electron beam 12 moves to point b due to the thermal expansion of the frame 8 and correction of the bimetal 9, and then becomes stable. As a result, the trajectory of the electron beam 12 passing through the pore becomes ( 12-a) to (1
It will vary within the range of 2-b).

When this phenomenon is observed using a dot-shaped phosphor screen as an example, as shown in FIG. 3, one phosphor 4a of the phosphor screen 4 and the electron beam 12 , the electron beam 12 is normal as shown in A at the start of operation, but as the aperture mask γ thermally expands, the electron beam 12 moves as shown in B, and as time passes, it gradually returns to the position of A and becomes stable. It turns out.

Here, if the correction by bimetal 9 is not done,
The electron beam 12 further moves from the position B to the position C and causes an undesired phosphor to emit light, resulting in so-called color shift.

Although it is reasonable when looking at one part in this way, it is impossible to actually completely compensate for thermal expansion over the entire screen using Bimetal 9, so a compromise adjustment must be made by observing the entire screen. That's how I do it.

Furthermore, although the correction by the bimetal 9 contributes to the thermal expansion correction of the frame 8, it is not uniform in each part of the screen, and complex movements occur depending on the position of the bin 5, that is, the fixed position of the shadow mask 6. This poses one of the most difficult problems in terms of design, and furthermore, this correction does not contribute significantly to the initial thermal expansion of the aperture mask 7, but rather serves to aggravate the phenomenon.

Furthermore, the conventional shadow masks have the following disadvantages from a manufacturing standpoint.

In other words, when manufacturing color picture tubes, usually 350
A heat treatment in the temperature range from 0.degree. to 450.degree. C. is carried out in several steps.

What is Panel 1 and Shadow Mask Dan? Although heat treatment is performed in advance before coating the phosphor, the heat treatment after coating also causes misalignment due to thermal deformation in the relative positions of the phosphor screen 4 and the aperture mask 7 on the inner surface of the panel.

This relative position originally needs to be set with extremely strict accuracy, but if the reproducibility in the heat treatment process deviates, it becomes a major cause of color shift, and this deterioration in reproducibility is mainly caused by the shadow mask. Thermal deformation, especially bimetallic9
This is due to thermal deformation of the frame 8.

Color picture tubes generally have a certain tolerance, taking into account the amount of misalignment between the phosphor screen and the shadow mask due to thermal expansion of the shadow mask during operation and thermal deformation during heat treatment as described above. In other words, it is designed with a landing margin, but if this margin is increased, the brightness of the screen will decrease, and if the margin is decreased, there is a risk of color shift, and in any case, the thermal expansion of the shadow mask And thermal deformation is the biggest problem in manufacturing color picture tubes having this type of color selection electrode.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color picture tube with good screen brightness and no color shift by providing a shadow mask that eliminates the drawbacks of the conventional art. Instead of using a metal frame as in the past, a ceramic frame, especially a frame made of ceramic, is used.

Embodiments of the present invention will be described in detail below with reference to FIGS. 4 to 12.

FIG. 4 shows a frame of a shadow mask to which an embodiment of the present invention is applied. This frame 13 is made of ceramic, especially ceramic, and has an appropriate plate thickness of approximately L.
The flange portion 14 has a rectangular ring shape with a cross section and is formed of a flange portion 14 and a skirt portion 15. There is a portion 17, and a plurality of fixing pieces 16 made of thin metal plates are bonded to the skirt portion 15 to attach the aperture mask γ.

It should be noted that this bonding of ceramic and metal is now easily carried out; for example, adhesives with a thermal expansion coefficient similar to that of ceramic
In addition to this, a metal plate of an appropriate size, for example 0.1 to 0.2 m thick, may be fixed with a heat-resistant adhesive.

In order to prevent these metals from rusting, it is effective to make the surface rust-proof by blackening treatment or the like.

As shown in FIG.
A rigid spring 10 is fixed.

That is, the aperture mask 7 is attached to the fixed piece 16 of the skirt part 15 by electric welding or the like, and the spring 10 is fixed to the holding part 17 of the flange part 14 with bolts 19.

It is desirable to use a metal with a coefficient of thermal expansion as close to that of ceramic as possible for this bolt 19, and in order to achieve even stronger fixation, it is better to weld the bolt 19 and the spring 10. , a spring hole 20 for engaging with the pin 5 of the panel 1 is formed, and at least one of the plurality of springs 10 attached in this way has a connector piece 21 attached to the fixing piece 16.
and conductive springs 22 are welded to each other, and from the conductive springs 22 to the shadow mask, and by extension to the pin 5.
Electrical conduction can be established from the phosphor screen to the aluminum conductive film on the four sides of the phosphor screen.

The reason why ceramic is used for the frame 13 in this X is that it has a much lower coefficient of thermal expansion and less thermal deformation than the conventional material, cold-rolled steel, and not only has good processing accuracy. Naturally, it has excellent heat resistance, has sufficient mechanical strength as a frame, and as a vacuum material, it releases less gas and is inexpensive.
At the same time, considering that the temperature rise of the shadow mask during operation is about 40 to 50 degrees Celsius, it is necessary to use a bimetal to compensate for the thermal expansion of the frame as in the conventional method. do not.

Therefore, when a shadow mask is constructed using a frame made of ceramic according to the present invention, it is possible to easily perform uniform correction over the entire screen, which was difficult with conventional bimetals, and to prevent color shift caused by thermal expansion of the frame. In addition, there is little thermal deformation during heat treatment during manufacturing, and because bimetal is not used, there is no permanent thermal deformation of bimetal, improving the reproducibility of shadow masks and phosphor screens. Because of these factors, it is possible to make the landing margin sufficiently small, and it is possible to obtain a stable color picture tube with high screen brightness without having to increase the power supply. .

In addition, in the manufacturing process of shadow masks, frames that have been conventionally pressed are first cleaned with triclean and then subjected to a blackening treatment at high temperatures to remove deterioration due to surface rust and distortion during pressing. However, the ceramic frame of this invention does not require such work at all, and also in the manufacturing process of color picture tubes.
Conventionally, before forming a phosphor screen, a panel and a shadow mask are combined in advance, and approximately 45
This requires a so-called pair baking process in which heat treatment is performed for several hours at a high temperature of 0°C, and thermal deformation in this process mainly occurs in the frame and bimetal, but in the ceramic frame of this invention, the heat deformation of the frame Since there is little deformation and there is no need to take thermal deformation of the bimetal into consideration, there is no problem in terms of characteristics even if this pair baking step is not performed, and this simplification of the process is also a great advantage of the present invention.

As mentioned above, the effect of thermal expansion of the aperture mask over several minutes at the start of operation occurs in this invention as well as in the conventional case, but for example, when high quality is required such as a high resolution color picture tube, In a special color picture tube, the aperture mask 7 can be made of an expensive but low expansion metal such as amber.

That is, in the conventional combination of the metal frame 8 and the aperture mask 7 made of amber material, the effect of using the amber material could not be expected due to deformation of the aperture mask 7 due to thermal expansion of the frame 8 during operation. As described above, in the combination of the ceramic frame 13 and the aperture mask 7 made of an amber material, the thermal expansion of the frame 13 itself can be reduced, so that the effect can be fully expected.

Further, in order to further reduce the thermal expansion of the ceramic frame 13 according to the present invention described above, the ceramic material may be dyed black with, for example, graphite, and this black treatment improves the thermal emissivity and is effective. The dye to be used may be one that exhibits a black color, releases little gas in vacuum, and does not affect the properties.

Further, ceramic is usually an electrically insulating material, and therefore the electric field is disturbed in the vicinity of the ceramic frame 13.
There is a possibility that the trajectory of the electron beam 12 may change.

In order to solve this problem, it is possible to mix an electrically conductive substance into the ceramic material to suppress the electrical resistance value of the frame 13 itself to a level that does not disturb the electric field.

In addition to this, the shadow mask of this invention also includes:
An electron shield made of a thin aluminum plate or the like as in the past can be provided to shield undesired electron beams around the mask and prevent deterioration of the color purity of the screen.

That is, as shown in FIG.
The electron shield 23 provided on the frame 13 may be bent toward the aperture mask T side to cover the inside of the frame.Another measure is to coat at least the inner surface of the aperture mask 13 with an electrically conductive material such as graphite. Alternatively, a metal film may be deposited or sealed.

In these cases, it goes without saying that the electron shield 23 and other conductive films should be electrically connected to the aperture mask 7.

Furthermore, in color picture tubes, in order to prevent the shadow mask from being deformed and causing color shift due to impacts during the manufacturing process or during transportation, the shadow mask is not subjected to thermal deformation as described above, but also to external pressure, i.e. It is necessary to prevent the shadow mask from deforming even when subjected to impact, and for this purpose, it is important to make the shadow mask l as lightweight as possible and to maintain a certain level of mechanical strength.

In conventional color picture tubes, as the size of the picture tube increases, the weight of the metal frame 8, which makes up most of the shadow mask, increases, which deteriorates the impact resistance. The number of panel pins 5 is four, and the shadow mask 6 is supported by four springs 10.

The deformation of the shadow mask due to impact is caused by the frame 8 and the bimetal 9. If the thickness of the frame 8 is unnecessarily increased, the workability will only deteriorate, and on the contrary, the bimetal 9 will deform due to the weight increase. This causes problems such as increased impact deformation, and the 4-pin support makes it extremely difficult to fit the shadow mask to the panel 1, resulting in a tendency for shadow mask misfits, or so-called "clipped", to occur frequently, resulting in poor accuracy. In order to satisfy the following, 3-pin support is desirable.

On the other hand, in the ceramic frame 13 of the present invention, in addition to having little mechanical deformation as described above, the thickness of each part can be freely set, so that only the plate thickness of mechanically weak parts, such as parts of the corners, can be set. By selectively thickening the pipe, the strength can be increased without significantly increasing the total weight, and since the bimetal 9 can be omitted, weight constraints can be reduced, for example, in the case of a large 2αl pipe. Therefore, a 3-pin support can be used.

The cross-sectional shape of the ceramic frame 13 in this invention does not necessarily have to be an L-shaped cross-section, but may be, for example, a T-shaped cross-section or a T-shaped cross-section as shown in FIG. In this case, a fixing piece 16 is provided inside the skirt portion 15, and the aperture mask 7 is attached to the inside of the skirt portion 15 by elongating the periphery thereof, and the unnecessary electron beam 12 is fixed by the extension portion 24 on the other side. It is preferable to shield the frame 13 to prevent disturbance of the electric field caused by the frame 13.

Next, FIG. 8 shows another embodiment of the ceramic frame 13 of the present invention, in which the height of the skirt portion 15 of the frame 13 is made low except for the portion 15a where the aperture mask 7 is attached. The fixing piece 16a is attached from the part 15a to the flange part 14, and the electron shield 23 as well as the aperture mask 7 can be attached to the fixing piece 16a. This makes it possible to reduce the weight of 13 and to shield it.

FIG. 9 shows an embodiment of a ceramic frame 13 according to the present invention having a linear cross-sectional shape. Positioning protrusions 25 are formed at a plurality of locations inside the frame 13, and one end of the frame 13 is formed with the protrusions 25 as a boundary. Aperture mask 7 on the side
An internal magnetic shield 26 made of a magnetic metal plate is attached to the other end to shield unnecessary external magnetic fields such as terrestrial magnetism.
is attached, thereby stabilizing the trajectory of the electron beam 12.

It is also a great advantage of the present invention that the ceramic frame 13 of the present invention can be easily and accurately processed by selecting various shapes and configurations.

Next, FIG. 10 shows a ceramic frame 1 of the present invention to which another means for attaching the aperture mask 7 is applied.
3, and in this example, frame 1
A plurality of caulking holes 26 are formed in the edge portion of the skirt portion 15 of No. 3, and the peripheral edge of the aperture mask 7 is caulked with a metal ring 27 using the caulking holes 26.

Furthermore, FIGS. 11 and 12 show embodiments of the ceramic frame 13 of the present invention in which different means are applied for attaching the spring 10. In the embodiment of FIG. Holding portions 17a, 17a for each pair are formed in a plurality of locations in 15 with insertion grooves facing each other, and both ends of a spring 10a having a spring hole 20a are inserted and fixed between these insertion grooves. In addition, in the embodiment shown in FIG. 12, a positioning piece 27 is similarly provided protruding from the skirt portion 15, and a metal piece 28 whose surface is blackened, for example, is adhesively fixed to this position. A spring 10b having a spring hole 20b is welded and fixed to the spring 10b.

As described above, various configurations are possible for attaching the aperture mask 7 and the spring 10 to the ceramic frame 13 in the present invention, and the point is that it is sufficient to prevent them from being displaced due to the heat treatment and impact. be.

As detailed above, according to the present invention, by using a ceramic material, especially ceramic, for the frame material constituting the shadow mask, thermal deformation during manufacturing and thermal expansion during operation of the shadow mask are reduced, and the brown color is reduced. In addition to being able to reduce misalignment and obtain a color picture tube with stable image quality and high brightness, it also eliminates the bimetal used to support the shadow mask, and omits or simplifies some of the manufacturing processes. It also has many features such as being able to improve impact resistance and allowing a greater degree of freedom in shadow mask design.

Note that the present invention is not limited to the shadow mask type color picture tube shown in each of the above embodiments, but in a broader sense, it can be applied to other color picture tubes having a color selection electrode like a shadow mask, such as a post-acceleration type color picture tube. Of course, it can also be applied to storage type special color picture tubes.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the configuration of a conventional shadow mask type color picture tube, and Figs. 2 and 3 show the movement of the shadow mask due to thermal expansion, the movement of the electron beam, and the shift of the screen during the same operation. 4 and 5 are perspective views and partial perspective views showing one embodiment of a shadow mask used in a color picture tube according to the present invention, and FIG. 6 is a partial sectional view showing another embodiment of the same, 7 to 9 are sectional views and partial perspective views of shadow masks according to still other embodiments of the above, FIG. 10 is a partial perspective view showing precedents for attaching the ceramic frame and aperture mask, FIG. 12 is a partial perspective view showing various precedents for attaching the ceramic frame and the spring. 1...Panel, 2...Funnel, 3
...Electron gun, 4...Color phosphor screen of each color, 5...Panel bin, 6...
... Shadow mask, T ... Aperture mask 1.10, 10a, 10b ... Spring,
12... Electron beam, 13... Frame, 14... Flange portion, 15.15a...
...Skirt part, 16.16a...Fixing piece, 17°17a...Frame holding part, 18
...Same holding hole, 19...Bolt, 20
．． 20a, 20b... Spring hole, 21.
... Connector piece, 22 ... Continuity spring, 2
3...Electron shield, 24...
- Frame extension, 25... Frame positioning protrusion, 26... Internal magnetic shield, 27.
...metal ring, 28...metal piece.

Claims (1)

[Scope of Claims] 1. A vacuum envelope consisting of a panel and a funnel, a colored phosphor screen of each color formed on the inner surface of the panel, and an electron gun mounted in the funnel and emitting three electron beams. , a color picture tube comprising at least an aperture mask disposed opposite to the phosphor screen and a shadow mask consisting of a frame that holds the periphery of the aperture mask and is mounted in the envelope; A color picture tube characterized by having a ceramic frame made of ceramic. 2. The color picture tube described in Patent No. 1, wherein the ceramic frame is comprised of a skirt portion for fixing the aperture mask, and a flange portion. 3. The ceramic frame is composed of a skirt portion for fixing the aperture mask and a flange portion, and fixing pieces made of metal plates are sealed or adhesively fixed to a plurality of locations on the skirt portion, and the fixing pieces are fixed to the fixing pieces. A color picture tube according to claim 1, characterized in that the aperture mask can be fixed by welding. 4. The color picture tube according to claim 1, wherein the ceramic frame is provided with an electron shield. 5. The ceramic frame is composed of a skirt portion for fixing the aperture mask and a flange portion, and fixing pieces made of metal plates are sealed or adhesively fixed at a plurality of locations from the skirt portion to the flange portion, and this fixing The color picture tube according to claim 1, characterized in that an aperture mask can be welded and fixed to the skirt side of one piece, and an electron shield can be welded and fixed to the flange side of the piece. 6. The color picture tube according to claim 1, wherein a portion of each corner of the ceramic frame is thicker than other portions. 7. A skirt portion is formed in the ceramic frame, and caulking holes are provided at a plurality of locations in the skirt portion, and the aperture mask can be caulked and fixed in the caulking holes. A color picture tube according to scope 1. 8 Positioning protrusions are provided at multiple locations inside the ceramic frame, so that the aperture mask can be fixed to one end and the internal magnetic shield can be fixed to the other end, using the positioning protrusions as boundaries inside the ceramic frame. A color picture tube according to claim 1, characterized in that: 9. The color picture tube according to claim 1, characterized in that the ceramic frame is provided at a plurality of locations with support portions for fixing spring pulls to be engaged with panel pins. 10 The ceramic frame is provided with holding portions having threaded holding holes at a plurality of locations, and a spring to be engaged with a panel pin can be bolted to the holding holes. A color picture tube according to scope 1. 11. Holding portions for one set of insertion grooves facing each other are provided at a plurality of locations on the ceramic frame, and both ends of a spring to be engaged with a panel pin can be inserted and fixed between these insertion grooves. A patented color picture tube featuring 12. The color image receiving device according to claim 1, wherein metal pieces for welding and fixing springs to be engaged with panel pins are positioned and sealed or adhesively fixed at a plurality of locations on the ceramic frame. tube. 13. The color picture tube according to claim 1, wherein the ceramic frame is dyed black. 14. The color picture tube according to claim 1, wherein an electrically conductive substance is mixed into the ceramic or mink material constituting the ceramic frame. 15. The color picture tube according to claim 1, characterized in that an electrically conductive substance is coated, sealed, or vapor-deposited on at least the inner surface of the ceramic frame. 16. The color picture tube according to claim 1, wherein Amber is used as a material for the aperture mask fixed to the ceramic frame. −