JP2006054137A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device with restrained generation of discharge and improved atmospheric pressure resistance force. <P>SOLUTION: A spacer structure 22 is provided between a first substrate 10 with a phosphor screen 16 formed and a second substrate 12 with a plurality of electron emission sources 18 fitted. A support substrate 24 of the spacer structure is provided with a first surface 24a opposed to the first substrate, a second surface 24b opposed to the second substrate, and a plurality of electron beam passing holes 26 each opposed to the electron emission sources. A plurality of spacers 30 are set in erection on the surface of the second surface. The support substrate is provided with a plurality of convex parts 40 each formed by protruding a part of the support substrate from the first surface and in contact with the first substrate through the phosphor screen, in free elastic deformation in a height direction of the spacer with the convex parts as a fulcrum. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device that includes substrates disposed opposite to each other and spacers disposed between the substrates.

  2. Description of the Related Art In recent years, various flat-type image display devices have attracted attention as next-generation lightweight and thin display devices that replace cathode ray tubes (hereinafter referred to as CRTs). For example, a surface conduction electron-emitting device (hereinafter referred to as SED) is being developed as a kind of field emission device (hereinafter referred to as FED) that functions as a flat display device.

  The SED includes a first substrate and a second substrate that are arranged to face each other at a predetermined interval, and these substrates form a vacuum envelope by bonding peripheral portions to each other through rectangular side walls. ing. A phosphor layer of three colors and a metal back are formed on the inner surface of the first substrate, and on the inner surface of the second substrate, a large number of electron-emitting devices corresponding to each pixel are arranged as an electron source for exciting the phosphor. ing.

  In the SED as described above, it is important to maintain a high degree of vacuum in the space between the first substrate and the second substrate, that is, in the vacuum envelope. When the degree of vacuum is low, the lifetime of the electron-emitting device, and hence the lifetime of the device, is reduced. Further, since the first substrate and the second substrate are in a vacuum, atmospheric pressure acts on the first substrate and the second substrate. Therefore, in order to support an atmospheric pressure load acting on these substrates and maintain a gap between the substrates, a large number of plate-like or columnar spacers are arranged between the two substrates.

In order to dispose the spacers over the entire surfaces of the first substrate and the second substrate, an extremely thin plate or an extremely thin columnar shape is used so as not to contact the phosphor of the first substrate and the electron-emitting device of the second substrate. A spacer is required. Since these spacers must be placed very close to the electron-emitting device, an insulating material must be used as the spacer. At the same time, when considering thinning the first substrate and the second substrate, more spacers are required. For example, Patent Document 1 discloses an apparatus in which a large number of columnar spacers are erected on a support substrate to form a spacer structure, and the spacer structure is disposed between the first and second substrates.
JP 2001-272927 A

  In the SED configured as described above, when displaying an image, a high voltage of, for example, 10 KV is applied between the first substrate and the second substrate as the acceleration voltage of the electron beam. When a getter is provided over the metal back under a high voltage, a current discharge state is likely to occur between the metal back and the first substrate. And when discharge generate | occur | produces, there exists a possibility that a fluorescent substance layer, a metal back, an electron emission element on a 2nd board | substrate, etc. may be destroyed.

  In the spacer structure configured as described above, it is difficult to form all the spacers at the same height, and there is a possibility that the height of the spacers varies. When the height of the spacer varies, it becomes difficult to stably support the atmospheric pressure load acting on the first substrate and the second substrate by the spacer, and the atmospheric pressure resistance of the envelope decreases. Further, a large load acts on the spacer having a high height, and this spacer may be damaged. In this case, the strength of the spacer structure itself is lowered. Furthermore, if a gap is formed between the tip of the spacer having a low height and the substrate, this gap can be a cause of discharge.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an image display device in which the occurrence of discharge is suppressed and the atmospheric pressure strength is improved.

  In order to achieve the above object, an image display device according to an aspect of the present invention is provided with a first substrate on which a phosphor screen is formed, and opposed to the first substrate with a gap therebetween, and directed toward the phosphor screen. An envelope having a second substrate on which a plurality of electron emission sources for emitting electrons are disposed, a first surface disposed between the first and second substrates and facing the first substrate, A second substrate facing the second substrate; a support substrate having a plurality of electron beam passage holes facing the electron emission source; and a second surface of the support substrate and the second substrate. And a plurality of spacers supporting atmospheric pressure acting on the first and second substrates, wherein the support substrate is formed by projecting a part of the support substrate from the first surface, and the fluorescence A plurality of protrusions in contact with the first substrate via a surface; It has been formed to be elastically deformable in the height direction of the spacer the protruding portion as a fulcrum.

  According to the present invention, even when the height of the spacer varies, the height variation can be absorbed by the elastic deformation of the support substrate with the convex portion as a fulcrum. Therefore, the gap between the second substrate and the spacer can be eliminated, and the atmospheric pressure load acting on the first and second substrates can be stably supported by the plurality of spacers, and at the same time due to the gap between the spacer and the substrate. It becomes possible to suppress discharge. Therefore, it is possible to provide an image display device that suppresses the occurrence of discharge and has improved atmospheric pressure strength.

Hereinafter, an embodiment in which the present invention is applied to an SED as a flat-type image display device will be described in detail with reference to the drawings.
As shown in FIGS. 1 to 3, the SED includes a first substrate 10 and a second substrate 12 each made of a rectangular glass plate, and these substrates have a gap of about 1.0 to 2.0 mm. Opposed. The first substrate 10 and the second substrate 12 constitute a flat rectangular vacuum envelope 15 whose peripheral portions are bonded to each other through a rectangular side wall 14 made of glass and the inside is maintained in a vacuum. Yes. The side wall 14 functioning as a bonding member is sealed to the peripheral edge of the first substrate 10 and the peripheral edge of the second substrate 12 by, for example, a sealing material 20 such as low-melting glass or low-melting metal. Are joined.

  A phosphor screen 16 that functions as a phosphor screen is formed on the inner surface of the first substrate 10 over almost the entire surface. The phosphor screen 16 is configured by arranging phosphor layers R, G, B (not shown) that emit light in red, blue, and green, and the light shielding layer 11, and these phosphor layers are formed in stripes or dots. . In the present embodiment, the phosphor layers R, G, and B are formed in a substantially rectangular dot shape. When the longitudinal direction of the first substrate 10 and the second substrate 12 is X and the width direction is Y, the phosphor layer is provided with R, G, and B alternately arranged in the X direction, and the same color in the Y direction. A phosphor layer is provided side by side. On the phosphor screen 16, a metal back 17 and a getter film 19 made of aluminum or the like are sequentially formed.

  On the inner surface of the second substrate 12, a number of surface-conduction electron-emitting elements 18 that emit electron beams are provided as electron emission sources for exciting the phosphor layers R, G, and B of the phosphor screen 16. Yes. These electron-emitting devices 18 are arranged in a plurality of columns and a plurality of rows corresponding to the pixels. Each electron-emitting device 18 includes an electron emitting portion (not shown) and a pair of device electrodes for applying a voltage to the electron emitting portion. On the inner surface of the second substrate 12, a large number of wirings 21 for supplying a potential to the electron-emitting devices 18 are provided in a matrix shape, and end portions thereof are drawn out of the vacuum envelope 15.

  As shown in FIGS. 2 and 3, the SED includes a spacer structure 22 disposed between the first substrate 10 and the second substrate 12. The spacer structure 22 includes a support substrate 24 made of a metal plate, and a large number of columnar spacers 30 that are integrally provided on the support substrate. The support substrate 24 is formed in a rectangular shape having a size corresponding to the phosphor screen 16, and has a first surface 24 a facing the inner surface of the first substrate 10 and a second surface 24 b facing the inner surface of the second substrate 12. These are arranged in parallel with these substrates.

  As shown in FIGS. 3 and 4, the support substrate 24 is formed with a thickness of 0.1 to 0.25 mm, for example, 0.12 mm, using, for example, an iron-nickel metal plate. A plurality of electron beam passage holes 26 are formed in the support substrate 24 by etching or the like. The electron beam passage hole 26 is formed in a rectangular shape of, for example, 0.15 to 0.25 mm × 0.15 to 0.25 mm. The electron beam passage holes 26 are arranged at a predetermined pitch along the X direction, and the Y direction is arranged at a pitch larger than the pitch in the X direction. The phosphor layers R, G, B of the phosphor screen 16 formed on the first substrate 10 and the electron-emitting devices 18 on the second substrate 12 are the same as the electron beam passage holes 26 in the X direction and the Y direction, respectively. They are arranged at a pitch and each face the electron beam passage hole.

  The support substrate 24 integrally includes a plurality of convex portions 40 formed by projecting a part of the support substrate from the first surface 24a. As will be described later, each convex portion 40 is formed by, for example, pressing, and is a hollow convex portion that protrudes from the first surface 24a toward the first substrate 10 side. The protruding height of each convex portion 40 is, for example, about 30 to 100 μm. Moreover, each convex part 40 is formed in dot shape, for example, elliptical shape. The plurality of convex portions 40 are provided side by side with a predetermined pitch in the X direction and the Y direction, are located between adjacent electron beam passage holes 26, and are provided on both sides of a spacer described later.

  The first and second surfaces 24a and 24b of the support substrate 24 including the protrusions 40 and the inner wall surfaces of the electron beam passage holes 26 are insulating materials mainly composed of glass, for example, Li-based alkali borosilicate glass. And an insulating layer 37 having a thickness of about 40 μm.

  The support substrate 24 is provided such that the first surface 24 a is in contact with the getter film 19 of the first substrate 10 via the convex portion 40. The convex portion 40 is provided at a position facing the light shielding layer 11 of the phosphor screen 16. The electron beam passage hole 26 provided in the support substrate 24 faces the phosphor layers R, G, B of the phosphor screen 16 and the electron-emitting devices 18 on the second substrate 12. Thereby, each electron-emitting device 18 is opposed to the corresponding phosphor layer through the electron beam passage hole 26. Further, the support substrate 24 can be elastically deformed along the direction perpendicular to the surface of the first substrate 10, that is, the height direction of the spacer 30 described later, with each convex portion 40 as a fulcrum.

  As shown in FIGS. 2 to 4, a large number of spacers 30 are erected integrally on the second surface 24 b of the support substrate 24. The extended end of each spacer 30 is in contact with the inner surface of the second substrate 12, here, the wiring 21 provided on the inner surface of the second substrate 12. Each of the spacers 30 is formed in a tapered shape having a diameter that decreases from the support substrate 24 side toward the extending end. For example, the spacer 30 is formed with a height of about 1.8 mm. The cross section of the spacer 30 along the direction parallel to the surface of the support substrate 24 is substantially elliptical. Each of the spacers 30 is mainly formed of a spacer forming material mainly composed of glass as an insulating substance.

  The spacers 30 are positioned between the electron beam passage holes 26 aligned in the Y direction. The plurality of spacers 30 are provided side by side with a predetermined pitch in the Y direction, and are provided side by side with a pitch larger than the predetermined pitch in the X direction. The convex portion 40 of the support substrate 24 is provided along with the spacer 30 along the Y direction, and is disposed on both sides of the spacer. The convex portion 40 is provided, for example, separated from the spacer 30 by one pixel.

  In the spacer structure 22 configured as described above, the support substrate 24 comes into contact with the first substrate 10 through the convex portions 40, and the extended end of the spacer 30 contacts the inner surface of the second substrate 12. The atmospheric pressure load acting on the substrate is supported, and the distance between the substrates is maintained at a predetermined value.

  The SED includes a voltage supply unit (not shown) that applies a voltage to the support substrate 24 and the metal back 17 of the first substrate 10. For example, a voltage of 8 kV is applied to the support substrate and a voltage of 10 kV is applied to the metal back. In the SED, when displaying an image, the electron-emitting device 18 is driven to emit an electron beam from an arbitrary electron-emitting device, and an anode voltage is applied to the phosphor screen 16 and the metal back 17. The electron beam emitted from the electron emitter 18 is accelerated by the anode voltage, passes through the electron beam passage hole 26 of the support substrate 24, and then collides with the phosphor screen 16. As a result, the phosphor layer of the phosphor screen 16 is excited to emit light and display an image.

Next, the manufacturing method of SED comprised as mentioned above is demonstrated. First, a method for manufacturing the spacer structure 22 will be described.
First, a metal plate made of Fe-50% Ni having a plate thickness of 0.12 mm is degreased, washed and dried, and then a resist film is formed on both sides. Subsequently, both sides of the metal plate are exposed, developed and dried to form a resist pattern. Thereafter, an electron beam passage hole 26 of 0.18 × 0.18 mm is formed at a predetermined position of the metal plate by etching. Next, as shown in FIG. 5A, a first press die 44 in which a plurality of arc-shaped recesses 42 corresponding to the protrusions 40 are formed, and a plurality of protrusions 46 corresponding to the recesses 42 are provided. The support substrate 24 is pressed by the second press die 48 thus formed. As a result, as shown in FIG. 5B, a support substrate 24 having a plurality of hollow protrusions 40 is formed. By using such pressing, the support substrate 24 having the convex portions 40 can be formed at low cost, which is suitable for mass production.
Subsequently, a glass frit is applied to the entire surface of the support substrate 24 to a thickness of 40 μm, dried, and baked to form the insulating layer 37.

  Thereafter, a rectangular plate-shaped mold having substantially the same dimensions as the support substrate 24 is prepared. The mold is formed in a flat plate shape using a transparent material that transmits ultraviolet light, for example, transparent silicon mainly composed of transparent polyethylene terephthalate. The molding die has a flat abutting surface that abuts on the support substrate 24 and a large number of bottomed spacer forming holes for molding the spacer. Each of the spacer forming holes opens on the contact surface of the mold and is arranged at a predetermined interval. Each spacer forming hole has a length of 1 mm, a width of 0.35 mm, and a height of 1.8 mm corresponding to the spacer. Thereafter, the spacer forming hole of the mold is filled with a spacer forming material. As the spacer forming material, a glass paste containing at least an ultraviolet curable binder (organic component) and a glass filler is used. The specific gravity and viscosity of the glass paste are appropriately selected.

  Subsequently, the mold is positioned so that the spacer forming holes filled with the spacer forming material are positioned between the electron beam passage holes 26, and the contact surface is brought into close contact with the second surface 24b of the support substrate. Thereby, the assembly which consists of the support substrate 24 and a shaping | molding die is comprised.

  Next, the filled spacer forming material is irradiated with ultraviolet rays (UV) from the outer surface side of the support substrate 24 and the mold using, for example, an ultraviolet lamp, and the spacer forming material is UV cured. At that time, the mold is formed of transparent silicon as an ultraviolet transmitting material. Therefore, ultraviolet rays are irradiated directly on the spacer forming material and through the mold. Therefore, the filled spacer forming material can be reliably cured to the inside.

  Thereafter, the mold is peeled from the support substrate 24 so that the cured spacer forming material remains on the support substrate 24. Next, the support substrate 24 provided with the spacer forming material is heat-treated in a heating furnace, the binder is removed from the spacer forming material, and then the spacer forming material is baked at about 500 to 550 ° C. for 30 minutes to 1 hour. Then vitrify. As a result, as shown in FIG. 6, the spacer structure 22 in which the spacers 30 are integrally formed on the second surface 24 b of the support substrate 24 is obtained.

  On the other hand, in the manufacture of the SED, the first substrate 10 provided with the phosphor screen 16 and the metal back 17 in advance, the second substrate on which the electron-emitting device 18 and the wiring 21 are provided and the side wall 14 is joined. 12 are prepared. Subsequently, after positioning the spacer structure 22 obtained as described above on the second substrate 12, the four corners of the support substrate 24 are placed on the metal pillars erected at the four corner portions of the second substrate. Weld. Thereby, the spacer structure 22 is fixed to the second substrate 12. Note that the supporting substrate 24 may be fixed at least at two locations.

  Thereafter, the first substrate 10 and the second substrate 12 to which the spacer structure 22 is fixed are placed in a vacuum chamber, the inside of the vacuum chamber is evacuated, and then a getter film 19 is formed on the metal back 17 of the first substrate. Form. Subsequently, the first substrate is bonded to the second substrate through the side wall 14, and the spacer structure 22 is sandwiched between the substrates. Thereby, SED provided with the spacer structure 22 is manufactured.

  According to the SED configured as described above, by providing the spacer 30 only on the second substrate 12 side of the support substrate 24, the length of each spacer is increased, and the distance between the support substrate 24 and the second substrate 12 is increased. Can be released. Thereby, the pressure resistance between the support substrate and the second substrate is improved, and the occurrence of discharge between them can be suppressed.

  The support substrate 24 has a plurality of convex portions 40, has a spring property with the convex portions serving as fulcrums, and is elastically deformable. Therefore, even when the spacer 30 has a variation in height, the variation in height can be absorbed by the elastic deformation of the support substrate 24. For example, when there is a spacer 30 that is higher than other spacers 30 and atmospheric pressure acts, a portion of the support substrate 24 where the spacer 30 is erected as shown in FIG. Elastically deforms toward the first substrate 10 with the convex portion 40 as a fulcrum, and absorbs variations in spacer height. Thereby, all the spacers 30 can be in contact with the second substrate 12 with no gaps at the tips.

  Therefore, the atmospheric pressure load acting on the first substrate 10 and the second substrate 12 can be stably supported by the spacer 30, and the atmospheric pressure resistance of the vacuum envelope 15 can be improved. At the same time, the spacer can be prevented from being damaged due to the variation in height.

  Furthermore, even when the height of the spacer 30 varies, it is possible to prevent the occurrence of a gap between the tip of the spacer and the second substrate 10 and to suppress the discharge caused by this gap. Since the support substrate 24 is covered with the insulating layer 37, the support substrate itself functions as a shield that suppresses discharge. Therefore, an SED that suppresses the occurrence of discharge and has improved atmospheric pressure strength can be obtained.

  The convex portion 40 of the support substrate 24 is in contact with the first substrate 10 through the getter film 19. Therefore, the metal back 17 and the support substrate 24 have the same potential, and the metal back and getter film are sandwiched between the first substrate 10 and the support substrate 24. In this case, the metal back 17 and the getter film 19 can be prevented from being peeled off, and the metal back and the phosphor screen can be prevented from being damaged. Thereby, good image quality can be maintained over a long period of time. At the same time, the occurrence of discharge due to the peeled metal back and getter film is suppressed, and an SED with improved reliability is obtained.

  The support substrate 24 is in contact with the first substrate 10 through the plurality of convex portions 40. Therefore, even when the getter film 19 is covered with the support substrate 24, the contact area between the support substrate and the getter film 19 is small, and the exposed area of the getter film can be increased. As a result, a decrease in getter efficiency can be reduced and a high vacuum can be maintained.

  In the above-described embodiment, the convex portion 40 of the support substrate 24 has an elliptical dot shape, but is not limited thereto, and may have another shape. According to another embodiment shown in FIG. 8, the convex portion 40 of the support substrate 24 is formed in a strip shape extending in the Y direction. The convex portions 40 are provided on both sides of the spacer 30. Such a support substrate 24 is formed by pressing as described above. In other embodiments, other configurations of the SED are the same as those of the above-described embodiments, and the same reference numerals are given to the same portions, and detailed descriptions thereof are omitted. Also in other embodiment mentioned above, the effect similar to embodiment mentioned above can be acquired.

  The present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  The diameter and height of the spacer, the dimensions and materials of the other components are not limited to the above-described embodiment, and can be appropriately selected as necessary. The formation position, the number of installations, and the like of the convex portions of the support substrate 24 can be changed as necessary. In addition, the present invention is not limited to the one using a surface conduction electron-emitting device as an electron source, but can be applied to an image display device using another electron source such as a field emission type or a carbon nanotube.

The perspective view which shows SED which concerns on 1st Embodiment of this invention. The perspective view of said SED fractured | ruptured along line AA of FIG. Sectional drawing which expands and shows the said SED. The top view which shows the support substrate of the spacer structure in said SED. Sectional drawing shown with the press die used for manufacture of the said support substrate. Sectional drawing which shows the spacer structure of said SED. Sectional drawing which expands and shows a part of said SED. The top view which shows the support substrate of SED which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... 1st board | substrate, 12 ... 2nd board | substrate, 14 ... Side wall, 15 ... Vacuum envelope,
16 ... phosphor screen, 17 ... metal back, 19 ... getter film,
18 ... an electron-emitting device, 22 ... a spacer structure, 24 ... a support substrate,
24a ... 1st surface, 24b ... 2nd surface, 26 ... Electron beam passage hole,
30 ... Spacer, 40 ... Projection

Claims (7)

A first substrate on which a phosphor screen is formed, and a second substrate on which a plurality of electron emission sources that emit electrons toward the phosphor screen are arranged opposite to the first substrate with a gap. An envelope with
A first surface facing the first substrate; a second surface facing the second substrate; and a plurality of electron beam passage holes facing the electron emission source. A supporting substrate having,
A plurality of spacers standing between the second surface of the support substrate and the second substrate and supporting the atmospheric pressure acting on the first and second substrates;
The support substrate is formed by projecting a part of the support substrate from the first surface, and has a plurality of convex portions that are in contact with the first substrate via the phosphor screen, and the convex portions An image display device formed so as to be elastically deformable in the height direction of the spacer with fulcrum as a fulcrum.   The image display device according to claim 1, wherein each of the plurality of convex portions is formed hollow and is provided between the plurality of spacers.   The image display device according to claim 1, wherein the plurality of convex portions are provided on both sides of each spacer.   The image display device according to claim 1, wherein each of the convex portions is formed in a belt shape.   The image display device according to claim 1, wherein each of the convex portions is formed in a dot shape.   The image display device according to claim 1, wherein the plurality of convex portions are formed by pressing the support substrate. A first substrate having a phosphor screen, a metal back provided on the phosphor screen, and a getter film formed on the metal back, and disposed opposite to the first substrate with a gap. A second substrate on which a plurality of electron emission sources for emitting electrons toward the phosphor screen are disposed, and an envelope,
A first surface facing the first substrate; a second surface facing the second substrate; and a plurality of electron beam passage holes facing the electron emission source. A supporting substrate having,
A plurality of spacers each standing on the second surface of the support substrate and having tip portions that contact the second substrate and supporting atmospheric pressure acting on the first and second substrates; Prepared,
The support substrate is formed by projecting a part of the support substrate from the first surface, and has a plurality of convex portions that are in contact with the first substrate, and the convex portions serve as fulcrums. An image display device formed to be elastically deformable in a height direction.

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