JP3323608B2 - Image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device for displaying an image using an electron beam.

[0002]

2. Description of the Related Art Conventionally, as an image display device, a cathode ray tube (CRT), which is excellent in view angle, colorization, luminance, and the like, has been put into practical use. 2. Description of the Related Art With the improvement in image quality of broadcasting, the need for a high-definition, large-screen, flat display device is rapidly increasing.

For this reason, several electron beam accelerated flat panel image display devices for displaying images have been proposed. For example, U.S. Pat. No. 3,408,532, U.S. Pat. No. 3,935,499 and JP-A-56-28.
No. 445 has an electron source arranged in a plane, extracts an electron beam from the electron source, and controls and accelerates the electron beam by a control electrode group provided with a large number of holes corresponding to the phosphor pixels. There is disclosed a configuration in which a desired phosphor pixel is illuminated by irradiating a fluorescent phosphor screen.

Further, as an element capable of emitting electrons with a simple structure, for example, MI Elinson (M.
I. A cold cathode device disclosed by Elinson et al. Is known [Radio Engineering Electron Physics (Radio. Eng. Elect.).
ron. Phys. ) Volume 10, 1290-1296
P. 1965].

This utilizes a phenomenon in which an electron is emitted by passing a current through a small area thin film formed on a substrate in parallel with the surface, and is generally called a surface conduction electron-emitting device. Have been.

[0006] In the conventional example of the flat panel type image display device using these planar cathodes, since the substrate material on which the planar cathodes are formed also serves as a member of an envelope serving as a vacuum vessel, it is resistant to atmospheric pressure. It is necessary to have a structure, which causes a problem that the substrate material becomes thick and extremely heavy, making it difficult to form and manufacture an image display member on the substrate material. As a method for solving these problems, Japanese Patent Application Laid-Open No.
Japanese Patent No. 32147 discloses a technique relating to an image display device.

In this image display device, the inner space of the evacuated image display device is divided into an image display unit and a vacuum exhaust / vacuum maintaining unit by a substrate material on which an electron source and the like are formed. The effect of the material on the image display unit is minimized, and the size of the flat plate other than the display unit of the image display device is reduced. Further, the substrate material can be made thinner and lighter, and its transportability is improved.

Hereinafter, the image display device (Japanese Patent Laid-Open No. 4-13 / 1990)
No. 2147) will be described with reference to the drawings. FIG. 6 shows a cross section of the flat panel image display device.
Is a substrate on which a planar cathode and a modulation electrode are formed, 2 is a planar cathode, 3 is an insulating layer, 4 is a modulation electrode, 5 and 6 are insulating outer frames, 7 is a getter, 8 is a phosphor and a metal back, 9 is a rear substrate, 10 is a display window plate, 11 is a vent for exhausting the inside of the vacuum vessel by the same exhaust system, and 20 is an exhaust pipe for exhausting the inside of the vessel. In the above device, the peripheral edges of the outer frames 5, 6 and the rear substrate 9 and the display window plate 10 are fused with a low melting point glass frit, and the inside is evacuated by a vacuum exhaust pipe.

[0009]

However, the conventional example has the following drawbacks when manufacturing a flat-panel image display device having a larger screen. As the size of the screen increases, the area of the rear substrate and the display window plate must be increased, but in order to withstand atmospheric pressure, the thickness of the rear substrate and the display window plate must be increased. And the thickness of the displayed image increases, and the resolution of the displayed image deteriorates. When the electron source is provided on the substrate, the cathode usually generates a small amount of heat, but the heat is generally released by conduction to the substrate in a vacuum. However, in the case of a larger screen, the element in the center is located at a distance farther from the peripheral part in contact with the atmosphere, so the heat dissipation efficiency due to conduction is not necessarily sufficient, and in the worst case, due to heat storage In some cases, characteristics such as the resistance value of the element slightly change, and uneven brightness or the like is observed at the peripheral portion and the central portion of the image display unit.

An object of the present invention is to provide an image display device which can solve the above-mentioned problems.

[0011]

According to the present invention, there is provided a flat image display device comprising an electron source substrate having an electron source formed therein inserted into a reduced pressure space formed between an image display window plate and a rear substrate. A spacer is placed between the display window plate and the electron source substrate.
Interposed between the electron source substrate and the rear substrate.
From a material having a thermal conductivity equal to or higher than the thermal conductivity of the electron source substrate.
The present invention relates to an image display device having a spacer interposed therein .

Further, the present invention provides an electron source arranged in a plane.
Emits light by irradiating an electron source substrate with an electron beam
Between the image display window plate containing the fluorescent screen member and the rear substrate
A vacuum exhaust pipe and vacuum that are provided in
The electron source, the electrode and the
A space having an optical surface member, the vacuum exhaust pipe and the getter;
And having a space separated by the electron source substrate,
A ventilation hole communicating between the two spaces is provided in the electron source substrate.
In the image display device, the electron separating the two spaces
A spacer is interposed between the source board and the image display
And further, between the electron source substrate and the back substrate.
A switch made of a material having a thermal conductivity higher than that of the electron source substrate
Image display device characterized by having a pacer interposed
About.

In one embodiment of the present invention, the electron source substrate
Modulates or accelerates the electron beam emitted from the electron source.
Electrodes. One embodiment of the present invention
In the above, interposed between the electron source substrate and the back substrate
The thermal conductivity of the spacer is between the electron source substrate and the image display window
The thermal conductivity of the interposed spacer is larger than that of the spacer.
Sign. Further, the material can be a metal material.
Wear.

[0014]

According to the image forming apparatus of the present invention, by providing spacers above and below the substrate that partitions the vacuum chamber,
In order to maintain the atmospheric pressure applied to the envelope with a spacer, it is possible to make the thickness of the envelope thinner and enlarge the screen as compared to the case where the whole display device does not have a spacer. Further, by giving the spacer a heat radiation effect, heat generated in the element substrate is appropriately released, and a stable image can be obtained.

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

FIG. 1 shows an embodiment of an image display apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes an electron source substrate on which a large number of planar cathodes 2, insulating layers 3, and modulation electrodes 4 are formed. .
The electron source substrate 1 is not limited to the above-described one, and various conventional types that emit an electron beam can be used. Reference numerals 5 and 6 denote insulating frames. The insulating frames 5 and 6, the rear substrate 9 and the display window plate 10 form a reduced-pressure space, and the electron source substrate 1 is inserted into the reduced-pressure space. I have. In the present invention, a spacer is provided between the display window plate 10, the electron source substrate 1, and the back substrate 9, and reference numeral 21 denotes the electron source substrate 1.
An upper spacer provided between the display panel 10 and the display window plate 22;
Is a lower spacer provided between the electron source substrate 1 and the back substrate 9.

The spacers support the pressure applied to the spacer display window plate 10 and the rear substrate 9 (atmospheric pressure, pressing force applied during handling, etc.) to prevent the window plate 10 and the rear substrate 9 from being damaged. In addition, it is preferable to transmit heat generated during operation of the electron source substrate 1 to the outside, and to have high mechanical strength and high thermal conductivity.

As such a material, for example, glass, Hastelloy (Ni.Mo.Fe alloy), aluminum, tungsten and the like are preferable.

The spacer may have any shape, such as a bar, a plate, and a curve, either alone or in combination. The spacers can also be arranged in parallel, staggered, or the like as appropriate. For example, if the spacer is a flat plate, the arrangement may be parallel, lattice, cross, or any other arrangement. Further, for example, the spacer arrangement in the central portion where heat radiation is difficult may be arranged at a higher density than the peripheral portion where heat radiation is easy. In short, any structure and material satisfying the above-mentioned requirements of pressure and heat radiation can be adopted.

In FIG. 1, 7 is a getter, 8 is a phosphor and a metal back, 11 is a vent for exhausting the inside of the vacuum vessel by the same exhaust system, and 20 is an exhaust pipe for exhausting the inside of the vessel. The above components are made of low melting point glass frit (not shown)
And the inside is evacuated by the vacuum exhaust pipe 20,
The vacuum exhaust pipe 20 is sealed, the getter 7 is operated, and the image display device is completed.

[0021]

EXAMPLES Hereinafter, the present invention will be specifically described with reference to specific examples. In addition, the embodiment and the reference example are indicated by serial numbers.
ing.

Reference Example 1 An image display device shown in the sectional view of FIG. 1 was manufactured.

In FIG. 1, 1 is an electron source substrate on which a planar cathode and a modulation electrode are formed, 2 is a planar cathode having a large number of planar cathodes formed on the substrate, 3 is an insulating layer, 4 is a modulation electrode, 5,
6 is an insulating frame, 7 is a getter, 8 is a phosphor and a metal back, 9 is a back substrate which is a lower surface portion of the image display device, 10 is a display window plate which is an upper surface portion of the image display device, Reference numeral 11 denotes a vent for exhausting the inside of the vacuum vessel by the same exhaust system, and reference numeral 20 denotes an exhaust pipe for exhausting the inside of the apparatus. Further, reference numeral 21 denotes an upper spacer provided between the substrate material and the display window plate, and reference numeral 22 denotes a lower spacer provided between the substrate material and the rear substrate. The above components are sealed with a low melting point glass frit (not shown), the inside is evacuated with a vacuum exhaust pipe 20, and the vacuum exhaust pipe 20 is sealed.
Was operated to complete the image display device.

Referring to FIG. 2, a method for manufacturing the image display device of the present invention will be described. First, a planar cathode 2, an insulating layer 3, and a modulation electrode 4 are formed by a vacuum film forming method and a photolithography technique using a blue plate glass having a thickness of 1.1 mm as the substrate 1, and then a 5 mm diameter substrate is formed on the substrate 1. A circular ventilation hole 11 was provided. At the same time, the upper spacer 21 and the lower spacer 22
Prepared by processing a blue sheet glass on a flat plate.
Further, an insulating frame 5 made of a blue sheet glass having a thickness of 5 mm is provided.
And 6, a back substrate 9 made of blue plate glass having a thickness of 5 mm and a width and a length of 300 mm, a vacuum exhaust pipe 20, a getter 7, and a 5 mm-thick plate having a transparent electrode, a phosphor, and a metal back. A display window plate 10 made of blue plate glass each having a length of 300 mm is formed by sealing with a low melting point glass frit as shown in FIG. 1, and then evacuated to about 1 × 10 (−7) Torr through a vacuum exhaust pipe 20. Was sealed. Next, the getter 7 is operated, and the space having the upper spacer between the display window plate and the substrate and the space having the lower spacer including the vacuum exhaust pipe and the getter between the rear substrate and the substrate are separated by the substrate material 1. The inside of the image display device having a structure separated into the above-described structure obtains the same vacuum through the vent hole 11 of the substrate, and the image display device has a structure in which spacers are formed on the upper side and the lower side of the substrate 1, respectively. Was completed.

Each spacer of the image display device manufactured in this reference example is arranged in parallel, and the interval between them is approximately 60 mm.
And The arrangement direction of the upper spacer and the lower spacer is different from each other by 90 degrees so that they do not overlap each other. However, even if the inside is in a vacuum state, it is possible to manufacture without breaking.

From this, by providing a spacer in the vacuum chamber, the thickness of the display window plate and the back substrate can be made thinner than in the case where there is no spacer, and as a result, Lighter weight than display without spacer.

Further, even if the screen size is increased, the area for supporting the atmospheric pressure of the display window plate can be divided by arranging the spacers, so that the thickness of the display window plate and the rear substrate is increased. It is possible to increase the size of the display window plate for displaying an image without any problem. Since the thickness of the display window plate does not need to be increased even when the screen size is increased, the resolution of image display does not change, and it goes without saying that a high-definition image can be displayed.

The planar cathode generates a small amount of heat during its operation. However, since the lower spacer is also disposed on the back side of the substrate on which the planar cathode is disposed as in the present embodiment , the substrate has a lower surface. Even with a planar cathode near the center, heat can be conducted to the rear substrate by the spacers in the vicinity and dissipated to the outside of the image display device, and as a result, uniform images can be displayed without uneven brightness. Was completed.

In order to support the atmospheric pressure in a safer direction, the number of spacers or the width of the spacers should be increased. However, in order to display a high-definition image, the pixels need to be increased. Since the size tends to decrease and the boundary between pixels is also narrow, the width of the upper spacer is limited in increasing. Then, when an image display device with a larger number of spacers was newly manufactured, improvement in the breaking strength by an impact test was observed. Also, as for the heat radiation efficiency, the effect of increasing the heat radiation efficiency was seen because the ratio per unit area occupied by the spacer under the substrate on the rear substrate increased.

According to the same idea, the upper spacer is left as it is, and the lower spacer has no restriction on the pixel size and the like. As a result, the heat radiation efficiency was improved.

In the present image display device, even if the getter 7 is operated, the getter is located below the substrate 1, so that the getter is the planar cathode 2, the insulating layer 3, the modulation electrode 4, the display window plate 10, etc. Because it did not adhere to the image, it did not affect the image display. Further, a getter can be freely provided quantitatively below the substrate, and there is no restriction for attaching the getter, so that it is easy to increase the amount of getter. When the number of getters was actually increased, the getter effect could be enhanced.

[0032] (Example 2) In the image display device shown in Reference Example 1, only the material of the lower spacer from blue plate glass, common nickel as the sealing material, an alloy of molybdenum and iron (typically Hastelloy Is a trade name of a heat-resistant and corrosion-resistant alloy mainly composed of nickel, and Hastelloy, whose composition has a coefficient of thermal expansion close to that of glass, is commercially available as a sealing material for glass. Hereinafter, "Hastelloy" is used. An image display device was manufactured in the same manner as in Reference Example 1. Then, when an image was displayed, an image display device having no luminance unevenness over the entire image display unit was obtained. Compared with the case where the lower spacer of Reference Example 1 manufactured with the same configuration was made of blue plate glass, And a more stable image was obtained. This is considered to be due to the effect of improving the heat radiation efficiency because the material of the lower spacer is made of Hastelloy. In fact, looking at the thermal conductivity of glass and Hastelloy, at room temperature, glass is almost 1j / (ms
k), but in the case of Hastelloy about 10 j / (m · s
K), which is about 10 times higher. Therefore, at least the lower spacer is selected by using a material having a higher thermal conductivity such as Hastelloy, and in particular, by selecting a material having a higher thermal conductivity than the above spacer, the number of the spacers is reduced. Without increasing the heat dissipation efficiency.

Further, Hastelloy used in the present embodiment is generally used as a material which is combined with glass and sealed with a low melting point glass frit, and has a similar coefficient of thermal expansion with soda lime glass. Could be changed from blue sheet glass to Hastelloy without any trouble.

Example 3 The material of the lower spacer used in Example 2 was changed to Hastelloy and was changed to aluminum. FIG. 3 schematically illustrates a method of fixing the lower spacer to the back substrate 9.
The lower spacer 22 is placed vertically on the upper side, and the lower end / sides of the lower spacer 22 is sandwiched by a glass block 31. The glass block is fixed on the rear substrate by a low melting point glass frit 32. Manufacturing methods other than using the method of indirectly fixing the lower spacer on the rear substrate in this way are as follows.
When an image display device was manufactured as in Reference Example 1, an image display device having better heat dissipation efficiency than that of Hastelloy of Example 2 could be manufactured. An image display device free from defects could be manufactured. This is because the thermal conductivity of aluminum is one digit higher than Hastelloy and two orders of magnitude higher than glass. In this case, the coefficient of thermal expansion of aluminum is twice or more higher than the coefficient of thermal expansion of soda lime glass, but the fixing method is such that the fixing method is indirectly fixed without directly bonding to the glass as in the embodiment of FIG. In this way, the influence of thermal expansion is made almost no hindrance in the manufacture of the image display device. By using a similar technique, a material having better heat radiation efficiency can be arbitrarily selected as the lower spacer regardless of the coefficient of thermal expansion.

Further, by using a metal such as aluminum or tungsten as a material of the spacer, a new effect that mechanical strength is improved, such as improvement in rigidity of the entire panel, is obtained.

Further, it is needless to say that the mechanical strength is further improved by devising the number, width, and arrangement of the lower spacers.

[0037] During the (Example 4) as the material of the lower portion of the spacer as in Reference Example 1 is glass, as shown in FIG. 4, arranged a spring-like metal spacer 41, reference example An image display device was manufactured in the same manner as in Example 1. In this case, when the metal spacer is made of copper having a considerably high thermal conductivity, an image display device capable of displaying a high-definition image with good heat radiation efficiency while having an atmospheric pressure resistant structure can be manufactured. Was. In this case, the atmospheric pressure is mainly supported by the lower spacer of the soda lime glass, and the heat radiation of the planar cathode is mainly performed by copper, which is a metal spacer, and the difference in thermal expansion coefficient is determined by the shape of the metal spacer. Is absorbed by changing. In this way, by using two or more lower spacer materials, more effective materials can be used, such as using inexpensive glass for supporting the atmospheric pressure and freely selecting an efficient material for heat radiation. Design is possible

[0038] (Reference Example 5) FIG. 5 shows a configuration diagram of an image display apparatus according to the fifth embodiment of the present invention. The configuration is the same as that of the first embodiment except that the shape of the lower spacer 22 is a substantially cross shape in which the planes of the spacers are crossed while maintaining the planes of each spacer at 90 degrees. Furthermore, when the manufacturing method was the same as that of Reference Example 1,
Although the upper spacer and the lower spacer were configured so as not to overlap all over, they could be manufactured without cracking even if the inside was in a vacuum state. Therefore,
The thickness of the display window plate and the back substrate can be made thinner than when there is no spacer, and as a result, the weight is reduced compared to a display device without a spacer. Therefore, even if the screen size is increased, it is possible to increase the screen size of the display window plate for displaying an image without increasing the thickness of the display window plate and the rear substrate, and the thickness of the display window plate increases the screen size. However, since it is not necessary to increase the thickness, the resolution of the image display does not change, and a high-definition image can be displayed as in Reference Example 1.

Further, the heat generated by the planar cathode can be efficiently radiated to the outside of the image display device by the lower spacer, and as a result, a uniform image can be displayed without uneven brightness.

Further, in the substantially cross-shaped lower spacer of the present embodiment, the shape of the lower spacer is substantially a cross, so that the image display device is mechanically deformed such as warping or bending or is caused by atmospheric pressure. Due to the shape effect of the lower spacer on the stress, the mechanical strength of the entire image display device was further improved. In addition, as for the heat dissipation efficiency, the effect of increasing the heat dissipation efficiency was observed because the ratio per unit area occupied by the spacer under the substrate on the rear substrate increased.

[0041]

As described above, in the display device having a structure in which the internal space of the evacuated image display device is divided by the electron source substrate, spacers are provided at the upper and lower portions of the substrate, respectively. Accordingly, the structure can support the atmospheric pressure without increasing the thickness of the display window plate, so that the weight of the display window plate and the rear substrate can be reduced, and a decrease in resolution can be suppressed. Further, since the heat generated by the cathode can be conducted to the outside and radiated mainly by the lower spacer, it is possible to display a uniform image without uneven brightness.

More specifically, by selecting the shape, width, and spacing of the spacer, a structure that supports the atmospheric pressure is realized, and the heat generated by the cathode can be efficiently transmitted to the spacer. By selecting a material having a high thermal conductivity as the material of the lower spacer, the heat radiation efficiency can be further improved.

Accordingly, it is possible to increase the screen size of the image display device, and it is possible to reliably manufacture a thin image display device capable of obtaining a high-definition image.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view showing one embodiment of the present invention.

FIG. 2 is an exploded perspective view of the image display device of the present invention shown in FIG.

FIG. 3 is a partial perspective view showing an example of a lower spacer.

4A and 4B show another embodiment of the present invention, wherein FIG. 4A is a schematic side sectional view, and FIG. 4B is a partial perspective view showing a lower spacer.

FIG. 5 is an exploded perspective view showing another reference example .

FIG. 6 is a schematic side sectional view showing a configuration example of a conventional image display device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electron source substrate 2 planar cathode 3 insulating layer 4 modulation electrode 5 frame 6 frame 7 getter 8 phosphor 9 back substrate 10 display window plate 11 ventilation hole 20 vacuum exhaust pipe 21 upper spacer 22 lower spacer 31 block 32 low melting glass 41 Metal spacer

Continuation of the front page (56) References JP-A-4-132147 (JP, A) JP-A-5-114373 (JP, A) JP-A-4-132136 (JP, A) JP-A-3-2550 (JP) (U, J) Special table Hei 3-501547 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 29/87 H01J 31/12 H01J 31/15

Claims (5)

(57) [Claims] 1. A flat image display device comprising an electron source substrate formed with an electron source inserted into a reduced-pressure space formed between an image display window plate and a rear substrate. A spacer is interposed between the electron source and the electron source.
Thermal conductivity of the electron source substrate between the substrate and the back substrate
Spacers made of a material with the above thermal conductivity are interposed.
The image display apparatus characterized by that. 2. An electron source substrate having an electron source arranged in a plane is provided between an image display window plate in which a fluorescent screen member which emits light by irradiation of an electron beam is provided, and a rear substrate. A vacuum exhaust pipe and a getter for maintaining a vacuum, and a space having the electron source, the electrode and the fluorescent screen member, and a space having the vacuum exhaust pipe and the getter are separated by the electron source substrate. In addition, in an image display device provided with a ventilation hole communicating with the two spaces in the electron source substrate, an electron source substrate separating the two spaces,
A spacer is interposed between the image display window plate and
The electron source substrate between the electron source substrate and the back substrate;
Spacer made of material with thermal conductivity higher than thermal conductivity is interposed
The image display apparatus characterized by being. 3. The image display device according to claim 1, wherein the electron source substrate further includes an electrode for modulating or accelerating an electron beam emitted from the electron source. 4. Interposed between an electron source substrate and a rear substrate
The image display apparatus according to any one of claims 1 to 3, wherein the greater than the thermal conductivity of the spacer thermal conductivity of the spacer is interposed electron source substrate and the image display window plates. 5. The image display device according to any one of 1-4, wherein said material is a metal material.