JP2005085581A - Field emission display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a field emission display device allowing a high-voltage application type field emission display device to be manufactured by a simple process, and capable of fundamentally keeping a vacuum characteristic and a conduction characteristic over a long time. <P>SOLUTION: This field emission display device has: a first substrate having an image display region on a substrate surface; and a second substrate disposed oppositely to the first substrate and composed by forming an electron emission part and an electron control part for controlling electrons emitted from the electron emission part on a substrate surface; and is characterized in that a high-voltage terminal for supplying a high voltage to the image display region is embedded in a spacer between the first and second substrates, and led out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a field emission display device, a so-called field emission display (FED).

  A field emission display device is known as one of flat display devices (flat panel display: FPD). 13 and 14 show a schematic cross-sectional structure of a conventional field emission display device. This field emission display device 1 is configured by arranging an anode substrate 3 having a phosphor screen 2 formed on the inner surface and a cathode substrate 5 having a field emission element 4 facing each other and hermetically sealing the surrounding portion. The

  The anode substrate 3 has a phosphor layer 11 that emits light when irradiated with electrons, a whole surface electrode to which a high voltage is applied, a black matrix layer 8 that serves as a light shield for improving contrast, and a luminous efficiency on the display surface. A metal back layer 12 is formed. The phosphor layer 11 and the black matrix layer 8 are formed, for example, in a strip shape in one direction (a direction orthogonal to the paper surface). The cathode substrate 5 is formed in a strip shape in the direction (the above-mentioned one direction) orthogonal to the cathode electrode 13 formed on the plate glass or glass panel in the other direction (direction along the paper surface) and the insulating layer 15 via the insulating layer 15. The formed gate electrode 14 and the electron emission portion 16 formed in the crossing region of both electrodes 13 and 14 are formed, and the field emission element 4 is formed.

  The electron emission portion 16 is formed on the cathode electrode 13 facing the insulating layer 15 and the opening 17 of the gate electrode 14. As an example of the electron emission portion, a CNT type using a carbon nanotube and a spint using Mo or the like as a material is known. The space where the anode substrate 3 and the cathode substrate 5 face each other needs to irradiate the phosphor screen 2 with electrons by field emission, and is maintained in a vacuum. In the conventional case structure, the support structure (support portion 10) is provided in the space between the opposing substrates 3 and 5 to prevent deformation and destruction due to atmospheric pressure.

  In the case of a low voltage driving type field emission display device, the distance between the anode substrate and the cathode substrate is very narrow, for example, about 200 μm. In this drive-type field emission display device, the space between the anode substrate and the cathode substrate is maintained by a high-accuracy spacer provided separately from the seal portion, and the vacuum is maintained by welding frit glass to the outer edge portion. A housing is formed. In this case, the electrical connection to the anode substrate is electrically connected to a metal back layer covering the phosphor layer formed on the anode substrate and patterned on the anode substrate (for example, a chromium film, This is done via a high-voltage extraction electrode portion made of a carbon film.

Further, in the high voltage drive type field emission display device, a configuration is adopted in which a drawer sensor unit connected perpendicularly to the conductive electrode of the anode substrate is derived using the exhaust hole of the vacuum casing (Patent Document 1, Patent Document 2).
Japanese Patent Laid-Open No. 10-50241 JP 2000-323076 A

  By the way, in the field emission display device having the above-described vacuum casing, the following problems may occur. In the structure having the high-voltage extraction electrode portion patterned on the anode substrate, when the glass seal wall made of frit glass is melted and fixed, the extraction electrode portion is also heated, causing diffusion into the glass seal wall, and the extraction electrode This may cause partial blockage in the part and deterioration of the conduction characteristics. Further, the glass seal wall is deteriorated, and the sealing performance is deteriorated. As a countermeasure, a method of avoiding poor conduction by a structure in which an electrode diffusion preventing layer is added has been proposed, but the process becomes complicated. Furthermore, there remains a problem that cannot be said to be a fundamental countermeasure.

  On the other hand, in the structure in which the electrode extraction hole is processed and sealed in the exhaust hole or the cathode substrate, the conduction performance deteriorates due to instability of the contact pressure between the conductive portion of the anode substrate and the lead wire, and the process in the seal / exhaust process It becomes a hindrance to the enlargement accompanying complications.

  In view of the above-described points, the present invention provides a field emission display device capable of manufacturing a high voltage application type field emission display device by a simple process and fundamentally maintaining long-term vacuum characteristics and conduction characteristics. With the goal.

  A field emission display device according to the present invention includes a first substrate having an image display area on a substrate surface, and is disposed to face the first substrate, and emits electrons from the electron emission portion and the electron emission portion on the substrate surface. A high voltage terminal for supplying high voltage to the image display area is embedded in a spacer between the first and second substrates. It is characterized by being derived.

  In the field emission display device of the present invention, since the high voltage terminal is led out embedded in a spacer that regulates the distance between the first and second substrates, the high voltage terminal does not react with the glass frit, and disconnection, leakage No current is generated. Further, the distance between the first and second substrates can be set wide. The process of forming the high voltage terminal is simplified. The stability of high voltage application can be secured.

The high-voltage terminal is preferably formed of a metal material that forms a surface oxide film that is hermetically bonded to the spacer.
In this case, the spacer can be formed of glass, and the high-voltage terminal can be formed of a metal material having a thermal expansion coefficient close to that of glass.
The high-voltage terminal is preferably formed of a metal material that maintains airtightness with the spacer even by heat in the exhaust process.
The high-voltage terminal is preferably formed of a metal material that maintains airtightness with the spacer even by Joule heat generated in the high-voltage terminal during operation.

The high voltage terminal can be formed using a metal wire or a metal foil as a core metal.
The high-voltage terminal preferably uses at least one of 50Ni—Fe, dumet wire, 42Ni-6Cr, and 47Ni-6Cr as the core metal.

The high-voltage terminal is preferably formed integrally with an elastic contact piece that comes into contact with the image display device.
The elastic contact piece has a contact portion shape that prevents contact scratches with the surface of the image display region, and can be formed of a heat-resistant conductive material that can withstand a thermal process.

  The high voltage terminal can be integrally formed with the peripheral spacer and press molding. The high-voltage terminal can be integrally formed with a member constituting a part of the peripheral spacer by press molding.

  According to the field emission display device of the present invention, the spacer sealed between the first substrate having the high voltage terminal having the image display region and the second substrate on which the electron emission portion and the electron control portion are formed. Therefore, it is possible to maintain a high vacuum for a long period of time and to improve the conduction performance. Compared with the low voltage application type field emission display device, the high voltage application type field emission display device which can set a wide interval between the first substrate and the second substrate has long-term vacuum characteristics and conduction performance with high reliability. Can be maintained. In addition, a high voltage application type field emission display device can be manufactured by a simple manufacturing process. By ensuring the safety of high voltage application, the high-pressure and high-luminance phosphor used in the cathode ray tube can be used, and the light emission amount of the field emission display device can be further increased.

By forming the high-voltage terminal and the metal material that forms a surface oxide film hermetically bonded to the spacer, long-term vacuum maintenance and conduction performance can be ensured in the field emission display device.
By forming the spacer with glass and forming the high-voltage terminal with a metal material having a thermal expansion coefficient close to that of glass, long-term vacuum maintenance and conduction performance can be ensured.
By forming the high-voltage terminal with a metal material that maintains the airtightness between the spacer and the spacer even by heat during exhaust processing, the spacer is not damaged by heating during exhaust processing, preventing gas leakage to the vacuum housing can do.
By forming the high-voltage terminal with a metal material that maintains airtightness between the spacer and the Joule heat generated at the high-voltage terminal during operation, the spacer is not damaged by the Joule heat based on the high current flowing through the high-voltage terminal. The gas leak to the vacuum casing can be prevented.

The high-voltage terminal can be formed integrally with the spacer by forming a metal wire or metal foil as a cored bar.
By using at least one of 50Ni-Fe, dumet wire, 42Ni-6Cr, and 47Ni-6Cr with a high-voltage terminal as a core metal, a high vacuum is maintained for a long time in a field emission display device, and conduction performance is improved. be able to.

  By integrally forming the elastic contact piece in contact with the image display area on the high voltage terminal, it is possible to ensure electrical connection between the high voltage terminal and the image display area. The elastic contact piece has a contact portion shape that prevents contact scratches with the surface of the image display area, and is formed of a heat-resistant conductive material that can withstand a thermal process, thereby electrically connecting the high-voltage terminal and the image display area. Can be stable.

  In this embodiment, a vacuum casing capable of fundamentally maintaining a long-term vacuum characteristic and a conduction characteristic is configured while allowing a high-voltage application type field emission display device to be manufactured by a simple process. The vacuum housing has a predetermined interval between a first substrate having a phosphor screen, a so-called anode substrate, and a second substrate having an electron emission cold cathode structure composed of an electron emission portion and an electron control portion, a so-called cathode substrate. The two peripheral portions are bonded to each other with a spacer, in this example, a frit glass through a seal wall having a glass core portion. Alternatively, the vacuum casing requires a first substrate on which a phosphor screen is formed, a so-called anode substrate, and a second substrate on which an electron emission cold cathode structure including an electron emission unit and an electron control unit is formed, a so-called cathode substrate. The opposite edges of the cathode substrate are bonded to each other with a spacer, in this example, a frit glass through a seal wall having a glass core portion, and a third substrate on the back side of the cathode substrate, a so-called back substrate. The cathode substrate and the cathode substrate are opposed to each other while maintaining a required interval, and both peripheral portions are bonded to each other with a spacer, in this example, a frit glass through a seal wall having a glass core portion. In the present embodiment, particularly in this vacuum casing, the high-voltage terminal is enclosed in a spacer that seals the anode substrate and the cathode substrate and led out by a cored bar, and the anode electrode surface is welded to the cored bar. The contact is made through a contact piece or spring to stabilize the application of the anode voltage and the extraction of the anode current.

  The high-voltage terminal for extracting the anode voltage / anode current is made of a metal material that constitutes a healthy oxide film for obtaining thermal expansion matching with a spacer to be sealed, for example, a glass spacer, and strong sealing. And a metal material capable of maintaining a vacuum against the heat sealing process of the vacuum casing and the Joule heat during electrical conduction. As a form of the metal material, a metal wire or a metal foil is used as a core metal. As a material of the cored bar, for example, 50Ni—Fe, dumet wire, 42Ni-6Cr, 47Ni-6Cr can be used. The spring tip shape that contacts the anode electrode layer has a contact portion shape that prevents contact scratches and peeling of the electrode film, and is made of a heat-resistant conductive material that suppresses deformation due to the thermal process of the housing, such as Inconel material. .

  In the present embodiment, a metal core that is a high-voltage terminal is press-molded into a peripheral glass material, and a spacer and a metal core are integrated. Alternatively, an encapsulated glass piece may be incorporated at the time of bonding of the casing by press-molding a core bar serving as a high-voltage terminal in advance into the shape glass constituting a part of the peripheral spacer.

  Embodiments of the present invention will be described below with reference to the drawings.

  1, FIG. 2 and FIG. 3 (enlarged view of essential parts) show an embodiment of a field emission display device according to the present invention. This example is applied to a field emission display device having a three-panel configuration. The field emission display device 21 according to the present embodiment includes a first substrate having a phosphor screen 22 as an image display region on the substrate surface, that is, an anode substrate 23, and an electron emission unit 24 and an electron emission unit 24 on the substrate surface. An electron control unit for controlling emitted electrons, that is, a second substrate on which a so-called gate electrode 25 is formed, that is, a cathode substrate 26, and a surface opposite to the surface of the cathode substrate 26 having the electron emission unit 24. A vacuum housing 33 is formed from the third substrate, i.e., the rear substrate 27, and a high-voltage terminal that supplies a high voltage through a glass seal wall 35A that seals between the anode substrate and the cathode substrate, i.e., the anode terminal 100. Is derived and configured. The anode substrate 23, the cathode substrate 26, and the back substrate 27 are formed of a flat glass panel, for example. The anode substrate 23 and the cathode substrate 26 are sealed (sealed) at a peripheral portion at a predetermined interval, and a closed space in which the inside is in a vacuum state, that is, a front space 31 that performs a so-called light emitting action is formed. The cathode substrate 26 and the back substrate 27 are sealed (sealed) at a peripheral portion at a required interval to form a closed space in which the inside is in a vacuum state, a so-called back space 32.

  The anode substrate 23, the cathode substrate 26, and the back substrate 27 form a front space 31 and a back space 32, and a vacuum casing 33 that does not have a column in the front space 31 is configured. The anode substrate 23 and the cathode substrate 26 are attached to the frit glass 36 with a first spacer, in this example, a first glass seal wall 35A having a peripheral shape having a glass core portion, so as to maintain a required distance at the peripheral portion. Are joined and hermetically sealed. The cathode substrate 26 and the back substrate 27 have a second spacer, in this example, a second glass having a peripheral shape (frame shape) having a glass core portion so as to maintain a required distance between the peripheral edges of both the substrates 26 and 27. The sealing wall 35B is sandwiched by the frit glass 36 and hermetically sealed.

When the phosphor screen 22 of the anode substrate 23 is a color phosphor screen, there is a red (R), green (G) and blue (B) phosphor layer 41 [41R, 41G, 41B] between each phosphor layer 41. And a black matrix layer 43 that serves as a light-shielding layer for improving contrast, and a metal as a reflective layer for efficiently reflecting the emitted light from the phosphor layer 41 by electron beam irradiation on the phosphor screen 22 to the viewer side. A back layer 42 is formed. An anode electrode is applied to the metal back layer 42 from the outside.
Each color phosphor layer 41R, 41G, 41B is formed in a stripe shape extending in a direction orthogonal to the paper surface, for example. The black matrix layer 43 is formed of, for example, a carbon stripe.

  In the cathode substrate 26, a plurality of strip-like cathode electrodes 28 extending in one direction (that is, a direction along the paper surface) are arranged in parallel on the substrate surface. An insulating layer 29 is formed on the surface including the cathode electrode 28, and a plurality of strip-like gate electrodes 25 extending in the other direction (that is, the direction orthogonal to the paper surface) so as to be orthogonal to the cathode electrode 28 are formed on the insulating layer 29. Arranged to do. Further, an electron emission portion 24 connected to the cathode electrode 28 is formed in the intersection region between the cathode electrode 28 and the gate electrode 25. In this example, the electron emission portion 24 is formed on the cathode electrode 28, the electron emission opening 30 is formed in the gate electrode 25 and the insulating layer 29 in the crossing region, and the electron emission portion 24 faces the bottom surface of the opening 30. Formed. The cathode electrode 28, the electron emission portion 24, and the gate electrode 25 constitute a field emission device. The crossing region where the electron emission portion 24 is formed corresponds to the phosphor layer 41 of one pixel on the anode substrate 23 side.

  The electron emission unit 24 is illustrated as a planar field emission device in FIGS. 1 and 2, but may be another type of field emission device. For example, if a conical electron emission portion made of a conductive material is formed on the cathode electrode 28, it is a so-called Spindt type field emission device. If the electron emission layer made of a conductive material is also formed with an opening 30 communicating with the gate electrode 25 and the insulating layer 29, and the end of the electron emission layer exposed in the opening 30 is an electron emission portion, an edge type It is a field emission device. In addition, field emission in which an electron emission portion is formed by separating a needle-like conductive material such as carbon nanotubes at a predetermined interval on the cathode electrode 28 in the opening 30 formed in the gate electrode 25 and the insulating layer 29. An element may be used. Note that one or a plurality of electron emission openings 30 in one pixel region may be provided. Also, the shape and arrangement of the openings 30 are arbitrary, and may be slit-shaped or mesh-shaped openings.

  The cathode substrate 26 is provided with four or more through holes 45 corresponding to four or more corners of one or more through holes for exhaust, in this example, an ineffective area that is off the effective screen. Further, the rear substrate 27 has one or more exhaust ports, in this example, one exhaust port 46 in the center of the substrate, and an exhaust pipe (that is, a chip-off pipe) 47 is connected to the exhaust port. The exhaust pipe 47 is joined to the back substrate 27 with frit glass. The vacuum casing 33 is evacuated in the spaces 31 and 32 through the exhaust pipe 47, and the exhaust pipe 47 is sealed after the vacuum exhaust.

  The peripheral glass seal wall 35 [35A, 35B] having the glass core part is preferably formed of the same glass material as the anode substrate 23 and the cathode substrate 26. The peripheral shape is such that the area where the phosphor screen 22 of the anode substrate 23 is formed, the so-called effective screen area, is the minimum opening area, and the outer shape of the anode substrate 23 and the back substrate 27 is the maximum outer shape. The shape of the peripheral glass seal wall 35 may be a frame shape having an opening, or may be formed by a combination of strip-shaped glass seal walls 35.

  The first glass seal wall 35A that seals the anode substrate 23 and the cathode substrate 25 while maintaining a required distance is embedded in the first glass seal wall 35A so as to be embedded in a high voltage terminal, a so-called anode terminal. 100 is led through. The anode terminal 100 is a terminal for applying an anode voltage to an anode conductive film, for example, a black matrix layer 43 extending to an ineffective area off the effective screen of the anode substrate 23, or a metal back layer 42 and taking out the anode current. It becomes. In this example, the anode terminal 100 is electrically connected to the metal back layer 42. FIG. 2 shows the main parts of the anode substrate 23, the cathode substrate 26, and the high-voltage terminal 100.

  For example, as shown in FIG. 4, the anode terminal 100 can be formed so as to be embedded in a glass piece 101 constituting a part of a peripheral glass seal wall 35A by press molding. In addition, as shown in FIG. 6, the anode terminal 100 can be formed so as to be integrally embedded in a peripheral glass seal wall 35 </ b> A by press molding. As shown in FIG. 5, an elastic contact piece (so-called contact anode spring) for securing electrical conduction with the metal back layer 42 of the anode conductive film is provided at one end inside the vacuum casing 33 of the anode terminal 100. 104 are welded together. The elastic contact piece 104 is formed, for example, in a ribbon shape, the center portion of which is welded to one end of a metal wire that becomes the anode terminal 100 and is extended in a V shape symmetrically about the metal wire.

  The anode terminal 100 is formed using a metal wire or metal foil as a core metal. In this example, the anode terminal 100 is formed using a metal wire as a core. As the metal core material of the anode terminal 100, a metal material as shown in Table 1 can be used. Preferably, a healthy surface oxide film for obtaining a strong seal close to the thermal expansion characteristics with the glass of the sealing partner, such as 50Ni-Fe, dumet wire, 42Ni-6Cr, 47Ni-6Cr, etc. Consists of metal material to be formed

  As described above, the metal core is enclosed in the glass seal wall 35A in the anode terminal 100 by pressing a metal wire into the glass piece 101 by press molding (see FIG. 4) or a frame-shaped glass seal wall 35A. It is necessary to incorporate at least one anode terminal 100 into the glass seal wall 35A. However, when the anode substrate 23 and the cathode substrate 26 are bonded together, if it is necessary to define the gap accuracy with the dimensional accuracy of the glass seal wall 35A, the surface flatness and the specified plate thickness can be obtained with respect to the required accuracy. Thus, it is necessary to perform additional processing by polishing or the like on both glass surfaces of the glass seal wall 35A.

  The elastic contact piece 104 welded to the metal wire of the anode terminal 100 is preferably a heat-resistant metal material such as an Inconel material that can suppress deterioration of the spring pressure due to thermal deformation caused by a heat process for bonding the casing 33 or the like. Furthermore, it is desirable that the tip of the elastic contact piece 104 that contacts the metal back layer 42 is molded into a shape that prevents contact scratches on the contact surface of the metal back layer 42 and peeling of the metal back layer, for example, a hemispherical shape. FIGS. 5A and 5B show examples of the attachment form of the elastic contact piece 104 to the anode terminal 100. One elastic contact piece 104 may be provided as shown in FIG. 5A, or a plurality of elastic contact pieces 104 may be provided as shown in FIG. 5B.

  The cathode substrate 26 is formed larger than the anode substrate 23 and the back substrate 27, is formed larger than at least the anode substrate 23, and the cathode electrode 28 and the gate electrode 25 are externally attached in a state where the three substrates 23, 26 and 27 are frit-sealed. Can be configured to be derived.

  The vacuum casing 33 is configured such that a column structure corresponding to a wall and a spencer is eliminated from the conventional vacuum casing, and the anode electrode and the cathode electrode are not structurally and physically connected. In the vacuum casing 33, a glass having a peripheral shape is formed by sandwiching the anode substrate 23, the rear substrate 27, and the cathode substrate 26 used for bonding the substrates 23, 27 with a vacuum strength corresponding to the support structure. Obtained in a glass casing made with a gap. Further, the glass casing also serves to maintain the spatial distance of the front space 31 that acts on light emission.

The anode substrate 23 and the back substrate 27 are formed with a plate thickness that does not deform when the front space 31 is vacuum and can withstand vacuum stress. Both the substrates 23 and 27 are formed of glass substrates having the same thickness.
The cathode substrate 26 is formed of a glass substrate that is thinner than the anode substrate 23 and the back substrate 27, and is formed to be larger than the anode substrate 23 and the back substrate 27 by a driving electrode (cathode electrode, gate electrode). In this example, the cathode substrate is formed of a general-purpose plate glass having a thickness of 1.3 mm to 3.0 mm, and is larger than the anode substrate 23 and the back substrate 27 by 5 mm or more in a state where the three substrates 23, 26, 27 are bonded together. For example, it can be formed so as to extend 5 mm or more on the left and right sides, or to extend 5 mm or more on the entire circumference.

  In the present embodiment, the tempering treatment is applied to the plate glass of the anode substrate 23 and the back substrate 27. In this vacuum housing 33, the air-cooling physical strengthening process is performed and a compressive stress is applied to the glass surface layer, thereby securing a glass strength of three times or more that of untreated glass. It should be noted that means such as a chemical strengthening method using ion substitution and a laser strengthening method using a laser beam can be used as long as the required strength can be secured.

  In the present embodiment, since a strut-less structure is used, the strength corresponding to the conventional strut structure is obtained by the glass thickness of each anode substrate 23 and back substrate 27. However, if the glass is too thick, the merchantability that leads to an increase in weight and cost is impaired. On the other hand, if the glass is too thin, problems such as product performance and safety occur, such as the vacuum housing 33 being deformed or broken by atmospheric pressure. Therefore, the thickness of the glass has a desirable range depending on the size of the housing 33.

  The upper limit of the glass thickness of the anode substrate 23 and the back substrate 27 is determined from the viewpoint of merchantability. That is, the thickness is determined not to exceed the weight of a normal cathode ray tube having the same screen size. Since the field emission display device uses a flat cathode, it can be made thinner and lighter than a cathode ray tube. One of the disadvantages of the cathode ray tube is that it has a large weight. Therefore, if the field emission display device is heavier than a cathode ray tube having at least the same screen size, the merchantability is impaired. For these reasons, the upper limit of the glass thickness of the anode substrate 23 and the back substrate 27 is set.

The lower limit of the glass thickness of the anode substrate 23 and the back substrate 27 is determined from the maximum vacuum stress that can be allowed in the housing 33 by replacing the safety standard of a general cathode ray tube with a field emission display device. FIG. 8 shows a result of calculating a desirable glass plate pressure range Q for each screen size in the anode substrate 23 and the back substrate 27. In FIG. 8, the vertical axis represents the glass plate thickness (mm), and the horizontal axis represents the effective screen size of the casing (the diagonal inch size). The straight line a is the maximum thickness of the substrate glass, and is obtained by the relational expression y = 0.51x + 6.1. The straight line b is the minimum thickness of the substrate glass, and is obtained by the relational expression y = 0.32x + 3.9.
Assuming that the thickness of the substrate glass is t1 (mm) and the effective screen size of the housing 33 is A, the thickness t1 of the substrate glass is in the relationship shown in Formula 1.

(Formula 1)
0.32 × A + 3.9 ≦ t1 ≦ 0.51 × A + 6.1

For example, in the case of 32 inches, the weight of the cathode ray tube is about 48 kg, and in order to make this 48 kg or less in the field emission display device, the glass plate thickness must be 222.5 mm or less as calculated by FEM simulation.
On the other hand, Table 2 shows the practical strength of the vacuum casing using plate glass. As shown in Table 1, when plate glass produced by the float method is used for each of the substrates 23 and 27, the maximum vacuum stress of the housing 33 can be allowed up to 3.75 kgf / mm ² . As a result of actually making a case and conducting an explosion-proof test, there is no safety problem up to the above allowable stress if a glass scattering prevention film and a glass scattering tape are applied around the glass substrate surface. Was confirmed. For example, in 32 inches, in order to make the maximum vacuum stress of the casing below the allowable stress, the glass plate thickness is 14 mm or more when calculated by FEM simulation.

  Further, in the vacuum casing 33 of the present embodiment, in order to reduce the maximum vacuum stress, it is desirable to round the corners around the casing, that is, to have a round shape as shown in FIG. 9A. Further, as shown in FIG. 9B, it is desirable that the macro shape on the back substrate 27 side be a funnel shape. By making the casing into such a shape, the glass plate thickness can be further reduced while satisfying the expression 1.

  However, if the thickness of the glass is too thick, it leads to an increase in weight and cost, and the merchantability is impaired. On the other hand, if the glass is too thin, problems such as product performance and safety occur, such as deformation and destruction of the vacuum casing 33 due to atmospheric pressure. In the present embodiment, the anode substrate 23 and the back substrate 27 are reinforced. In this vacuum housing 33, the air-cooling physical strengthening process is performed and a compressive stress is applied to the glass surface layer, thereby securing a glass strength of three times or more that of untreated glass. It should be noted that means such as a chemical strengthening method by ion substitution can be used as long as the necessary strength for the strengthening treatment can be secured.

Here, in the vacuum casing 33, the ideal structure that can withstand vacuum deformation and vacuum stress is to make the casing spherical. The vacuum casing of this example is composed of three substrates, and the anode substrate 23 and the back substrate 27 are arranged in a substantially symmetrical manner with the central cathode substrate 26 interposed therebetween. Since the cathode substrate 26 that does not like vacuum deformation is not subjected to atmospheric pressure, it can be formed of a glass substrate that is thinner than the anode substrate 23 and the back substrate 27. On the other hand, in the anode substrate 23 and the back substrate 27, as shown in FIG. 9, in order to make the peripheral portion as close to a sphere as possible, it is rounded and the bonding width D is the corresponding substrate, in this case, the anode substrate and the back substrate. The board thickness t can be set to be greater than or equal to (D ≧ t, t ′). With this condition setting, the support structure of the vacuum housing 33 can be further stabilized. The bonding width is effective for stress distribution and suppression of substrate deformation.
FIG. 9A shows a structure in which the peripheral portions of the anode substrate 23 and the back substrate 26 are rounded and frit-sealed through glass seal walls 35 [35A, 35B]. FIG. 9B shows a configuration in which the peripheral edge portion of the anode substrate 23 is rounded, the peripheral edge portion of the back substrate is curved to be rounded, and frit-sealed through the glass seal walls 35 [35A, 35B]. is there.

  In the back space 32 of the vacuum housing 33, a getter device 51 for maintaining the front space 31 and the back space 32 in a high vacuum is disposed. As shown in FIG. 10, the getter device 51 is configured by accommodating a getter material 53 in a getter container 52 made of an annular metal. One end of a support member, for example, one end of a wire-like support spring 54 is joined to the getter device 51, and a C-type spring 56 inserted into the exhaust pipe 47 is joined to the other end of the support spring 54. The C-type spring 56 is configured as a spring in which a longitudinal split groove 58 is formed in the cylindrical body 57 and the cross-sectional shape is C-shaped. A pair of contact pieces 61 and 62 that come into contact with the cathode substrate 26 and the back substrate 27 when disposed in the back space 32 on the support spring 54 side are joined to the getter container 51, and the cathode substrate is also provided on the opposite side. 26 and the contact pieces 63 and 64 which contact the back substrate 27 are joined. One contact piece 61, 62 has a ribbon shape that sandwiches the support spring 54 from above and below. Among the other contact pieces, the contact piece 63 has a ribbon shape, and the contact piece 64 extends in parallel so as to straddle the left and right around the contact piece 63 in order to stabilize the arrangement of the getter device 51. It has a letter shape.

  When the getter device 51 is arranged, as shown in FIG. 11, the C-type spring 56 is inserted into the exhaust pipe 47 with a reduced diameter, and after insertion, the C-type spring 56 is crimped and held on the inner wall of the exhaust pipe 47 by the spring force. The getter device 51 is arranged in the back space 32 through the mold spring 56 and the support spring 54. In the state where the getter device 51 is disposed in the back space 32, the contact pieces 61 and 63 and the contact pieces 62 and 64 come into contact with the cathode substrate 26 and the back substrate 27 and are supported in a hollow manner. After the exhaust pipe 47 is sealed, the getter material 53 is evaporated by high-frequency heating from the outside, and a getter vapor deposition film 53 </ b> A is formed on the back surface of the cathode substrate 26.

  Next, a manufacturing method for the components of the field emission display device 21 will be described. First, seal members are formed on both surfaces of the glass seal wall 35A. In this example, slurry-like frit glass is applied on each side and naturally dried. Next, as shown in FIG. 7, the first glass seal wall 35 </ b> A is placed on the periphery of the anode substrate 23. In the illustrated example, the glass seal wall 35 </ b> A is composed of a glass piece 102 in which the high-voltage terminal 100 is integrated and a glass member 102 that constitutes the other part. On this, the cathode substrate 26 is aligned with the position facing the anode substrate 23. At this time, a getter device 51 is disposed on the rear substrate 27 by inserting a C-type spring 56 integral therewith into the exhaust pipe 47.

Next, the substrate structure subjected to this alignment is subjected to main baking in a baking electric furnace at about 430 ° C. so that the sealing members are fused and the three substrates are firmly bonded. In this case, the anode substrate 23, the cathode substrate 26, and the rear substrate 27 are prevented from being displaced due to melting of the frit glass, and processed with a heat-resistant material for the purpose of securing the adhesive strength of the frit glass more firmly. It is desirable to hold the substrate bonding structure with a click spring and put it into a thermal furnace. Subsequently, evacuation is performed from the exhaust pipe 47 of the housing bonded by the seal member by a vacuum pump until the degree of vacuum is on the order of 10 ⁻⁶ Pa.

  Further, for the purpose of promoting degassing of the substrates 23, 26, 27 and the sealing member, the whole is continuously evacuated in a heated atmosphere at 350 ° C., for example. Alternatively, degassing by electron beam irradiation by field emission may be performed by applying a voltage to the cathode electrode, the gate electrode, and the anode electrode while exhausting is continued. Moreover, you may implement the degassing process of this combination. After the degassing process, the exhaust pipe 47 is sealed and the getter material of the getter device 51 disposed in the back space 32 in the vacuum housing 33 is flushed, so that the vacuum can be stably maintained for a long period of time. A field emission display 21 that can be manufactured can be manufactured.

  According to the field emission display device 21 according to the above-described embodiment, the anode terminal 100 is led out by being embedded in the first glass seal wall 35 </ b> A sealed between the anode substrate 23 and the cathode substrate 26. Therefore, the high vacuum in the vacuum housing 33 can be maintained for a long time and the conduction performance of the anode terminal 100 can be enhanced. By using a metal material such as 50Ni-Fe, dumet wire, 42Ni-6Cr, 47Ni-6Cr, etc. shown in Table 1 as the anode terminal 100, the surface of the anode terminal 100 is formed by a thermal process during sealing with frit glass. Since the oxide film is formed and has a thermal expansion coefficient close to that of glass, it adheres firmly to the glass seal wall 35A as a sealing partner. Therefore, it is possible to prevent gas leakage to the vacuum casing 33 without damaging the glass seal wall 35A due to heat during exhaust processing. Further, the glass seal wall 35A is not damaged by Joule heat caused by the anode current flowing through the anode terminal 100 during operation, and gas leakage to the vacuum casing 33 can be prevented.

  By integrally forming the elastic contact piece 104 at one end of the anode terminal 100, the electrical connection between the anode terminal 100 and the metal back layer (anode electrode) 42t of the anode substrate 23 is ensured. By forming the tip of the elastic contact piece 104 in the hemispherical shape 105, it is possible to prevent the metal back layer 42 that contacts the elastic contact piece 104 from being damaged by contact. In addition, by forming the elastic contact piece 104 with a heat-resistant conductive material that can withstand a thermal process, such as Inconel material, the electrical connection between the anode terminal 100 and the metal back layer 42 can be stabilized.

  By adopting the anode terminal derivation form of the present embodiment for the high voltage application type field emission display device which can set the gap between the anode substrate 23 and the cathode substrate 26 wider than the low voltage application type field emission display device. In addition, long-term vacuum characteristics and conduction performance can be maintained with high reliability. In addition, a high voltage application type field emission display device can be manufactured by a simple manufacturing process. By ensuring the safety of high voltage application, the high-pressure and high-luminance phosphor used in the cathode ray tube can be used, and the light emission amount of the field emission display device can be further increased.

  Since the anode substrate 23 is disposed on one side of the cathode substrate 26 with a front space (light emitting space) 31 therebetween, and the back substrate 27 is disposed on the other side of the back space 32, the cathode substrate 26 has a large size. The atmospheric pressure does not act directly, and the front space 31 can be made into a column-less structure by selecting the plate thickness of the anode substrate 23 and the back substrate 27. At least, the effective screen area can be a pillar-less structure. Since the support is not required, the display image is not disturbed, discharged, obstructed, or the like by the support, and a high-quality image display device can be obtained.

  Since it is not necessary to provide support columns, the degree of freedom in the interval (so-called height) between the anode substrate 23 and the cathode substrate 26 by the first glass seal wall 35A is increased, and the interval can be set large. That is, the distance between the anode substrate and the cathode substrate can be set wider than that of a conventional low voltage application type field emission display device. Therefore, a high voltage application type field emission display device can be provided.

  Incidentally, the distance between the anode substrate and the cathode substrate of the conventional low voltage application type field emission display device is about 1.1 to 1.2 mm, but in the present embodiment, it is between the anode substrate 23 and the cathode substrate 26. It is possible to make the distance of the distance more than the conventional distance, for example, about 4.0 mm.

In the present embodiment, the voltage characteristics are stable, and a high voltage exceeding 15 kV can be applied. A black matrix for hiding the support in the phosphor coating area is also unnecessary, and the phosphor coating area can be increased. Since high voltage can be applied, general-purpose phosphors can be used, and the support insertion process is unnecessary, simplifying the manufacturing process, and achieving this type of large image display device at low cost. It becomes possible to do.
Since the stability of high voltage application can be ensured, the high-pressure and high-luminance general-purpose phosphor used in the cathode ray tube can be used, and the discharge characteristics can be improved. The light emission amount of the field emission display device can be further increased.

  By arranging the getter device 51 in the back space 32, the getter material is not deposited on the electron emission portion 24 and the gate electrode 25 of the cathode substrate or the phosphor screen 22 of the anode substrate 23 when the getter flash is performed. It can be applied only to a wide area on the back surface of the cathode substrate 26. The getter vapor deposition film 53A deposited over a wide area can sufficiently adsorb the residual gas and generated gas in the front space 31 through the through hole 45 provided in the cathode substrate 26, and can maintain a high vacuum. This eliminates contamination and damage to the field emission cathode, and allows the field emission display device to have a long life.

  Since the getter device 51 is disposed in the back space 32, a high-frequency coil for heating and evaporating the getter material, so-called high-frequency induction heating means, may be disposed on the back surface side of the back substrate 27. Does not require any special consideration.

  When the getter device 51 is installed, the C-type spring 56 connected to the getter device 51 can be simply and accurately installed by inserting it into the exhaust pipe 47. Since the C-type spring 56 is used as the supporting means, even if it is inserted into the exhaust pipe 47, there is no problem in the exhaust process.

FIG. 12 shows another embodiment of the field emission display device according to the present invention. In this example, the present invention is applied to a field emission display device having a two-panel structure.
The field emission display device 71 according to the present embodiment includes an anode substrate 32 on which a phosphor screen 22 and a metal back layer 42 are formed as described above, and a cathode electrode 28, an insulating layer 29, a gate electrode 25, and an opening as described above. A cathode substrate 26 having an electron emitting portion 24 facing 30 is formed, and both the substrates 23 and 26 are sealed with frit glass through a glass seal wall 35 at the peripheral portion. An exhaust pipe 47 is joined to the cathode substrate 26, and the closed space between the substrates 23 and 26 is exhausted to a high vacuum by the exhaust pipe 47, and a vacuum casing 72 is configured by the anode substrate 23 and the cathode substrate 26. The glass seal wall 35 is led out so that the anode terminal 100 similar to that described above is embedded, and the elastic contact piece 104 welded to the anode terminal 100 is in electrical contact with, for example, the metal back layer 42 serving as the anode electrode. Configured. Since the configurations of the anode substrate 23, the cathode substrate 26, and the anode terminal 100 are the same as those described above, a duplicate description is omitted. The glass seal wall 35 is configured in the same manner as the glass seal wall 35A described above. Although not shown, the getter device is disposed in the bag space.

According to the field emission display device 71 according to the present embodiment, since the anode terminal 100 is led out through the glass seal wall 35, the high vacuum in the vacuum casing 72 is maintained for a long time, and the anode terminal 100 conduction performance can be increased. By adopting the anode terminal derivation form of the present embodiment for the high voltage application type field emission display device which can set the gap between the anode substrate 23 and the cathode substrate 26 wider than the low voltage application type field emission display device. In addition, long-term vacuum characteristics and conduction performance can be maintained with high reliability. In addition, a high voltage application type field emission display device can be manufactured by a simple manufacturing process. By ensuring the safety of high voltage application, the high-pressure and high-luminance phosphor used in the cathode ray tube can be used, and the light emission amount of the field emission display device can be further increased.
In addition, the same effects as those of the anode terminal 100 described above can be obtained.

  Also in the field emission display device 71, when the anode substrate 23 and the cathode substrate 26 are bonded together, if the interval accuracy needs to be defined by the dimensional accuracy of the glass seal wall 35, the surface flatness with respect to the required accuracy is obtained. Therefore, it is necessary to perform an additional process by polishing or the like on both surfaces of the glass seal wall 35 so that the property and the specified plate thickness can be obtained. In addition, when a gap maintaining member or the like, which is a combination of a concave portion and a convex portion called a tack post, for example, is introduced between the substrates 23 and 26, the glass seal wall 35A of the glass seal wall 35A substantially depends on the accuracy of the gap maintaining member. The burden of dimensional accuracy and shape control can be reduced.

1 is a cross-sectional view of an embodiment of a field emission display device according to the present invention. 1 is a perspective view of an embodiment of a field emission display device according to the present invention. FIG. 1 shows an exploded view of an embodiment of a field emission display device according to the present invention. FIG. The perspective view of the principal part of one Embodiment of the field emission display apparatus which concerns on this invention is shown. A shows a perspective view of essential parts of an embodiment of a field emission display device according to the present invention. B shows a perspective view of the main part of another embodiment of the field emission display device according to the present invention. The perspective view of the principal part of one Embodiment of the field emission display apparatus which concerns on this invention is shown. The perspective view of the principal part of other embodiment of the field emission display apparatus which concerns on this invention is shown. The graph of the relationship between the glass plate thickness of the field emission display apparatus which concerns on this invention, and an effective screen size is shown. A shows a sectional view of a main part of a panel substrate of an embodiment of a field emission display device according to the present invention. B is a cross-sectional view of the main part of a panel substrate of another embodiment of the field emission display device according to the present invention. The perspective view of the principal part of the getter part of one Embodiment of the field emission display apparatus which concerns on this invention is shown. The perspective view of the principal part of the getter part of one Embodiment of the field emission display apparatus which concerns on this invention is shown. FIG. 6 shows a perspective view of another embodiment of a field emission display device according to the present invention. A sectional view of a conventional field emission display device is shown. 1 is a perspective view of a conventional field emission display device.

Explanation of symbols

  1, 2, 71 ... Field emission display device 2, 22 ... Phosphor screen 3, 23 ... Anode substrate 4, Field emission element 5, 26 ... Cathode substrate 8, 43 ... Black matrix Layer 10 .. Column part 11 .. Phosphor layer 12, 42 .. Metal back layer 13, 28 .. Cathode electrode 14, 25 .. Gate electrode 15, 29 .. Insulating layer 16 24..Electron emission part, 17..Opening, 27..Back substrate, 30..Opening, 31..Front space, 32..Back space, 33..Vacuum housing, 35, 35A..Glass seal wall 41 [41R, 41G, 41B]... Each color phosphor layer, 45.. Through hole, 46 · Exhaust port, 47 · · Exhaust pipe, 100 · · Anode terminal, 51 · · Getter device, 52 · · Getter container , 53 ・ ・ Getter material, 54 ・ ・ Support Ring, 56 ... C-type spring, 57 ... cylindrical body, 63, 64 ... contact piece, 101 ... glass pieces, 104 ... resilient contact piece

Claims (11)

A first substrate having an image display area on the substrate surface, an electron disposed to face the first substrate and controlling electrons emitted from the electron emitting portion and the electron emitting portion on the substrate surface A second substrate on which a control unit is formed,
A field emission display device, characterized in that a high voltage terminal for supplying a high voltage to the image display area is embedded and led out in a spacer between the first and second substrates. The field emission display device according to claim 1, wherein the high-voltage terminal is formed of a metal material that forms a surface oxide film that is hermetically bonded to the spacer. 2. The field emission display device according to claim 1, wherein the spacer is made of glass, and the high-voltage terminal is made of a metal material having a thermal expansion coefficient close to that of the glass. The field emission display device according to claim 1, wherein the high-voltage terminal is formed of a metal material that maintains airtightness with the spacer even by heat in exhaust processing. The field emission display device according to claim 1, wherein the high-voltage terminal is formed of a metal material that maintains airtightness with the spacer by Joule heat generated in the high-voltage terminal during operation. The field emission display device according to claim 1, wherein the high-voltage terminal is formed by using a metal wire or a metal foil as a core metal. The field emission display device according to claim 1, wherein the high-voltage terminal is made of at least one of 50Ni-Fe, dumet wire, 42Ni-6Cr, and 47Ni-6Cr as a core metal. The field emission display device according to claim 1, wherein an elastic contact piece that comes into contact with the image display region is integrally provided on the high-voltage terminal. The electric field according to claim 8, wherein the elastic contact piece has a contact portion shape that prevents contact scratches with the surface of the image display region, and is formed of a heat-resistant conductive material that can withstand a thermal process. Emission display device. The field emission display device according to claim 1, wherein the high-voltage terminal is formed integrally with the peripheral spacer by press molding. 2. The field emission display device according to claim 1, wherein the high-voltage terminal is formed integrally with a member constituting a part of the peripheral spacer by press molding.

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