JP2005158498A - Flat panel display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat panel display device for improving reliability and visual quality by suppressing generation of discharge and applying a predetermined voltage stably to a metal back layer. <P>SOLUTION: A first substrate 10 and a second substrate 12 are oppositely arranged with a clearance. A phosphor layer is formed on an inner surface of the first substrate, and the metal back layer 17 is superimposed on the phosphor layer. The metal back layer includes a plurality of partitioned layers 17a electrically independent and divided. The second substrate is provided with an electron emission element 18 for exciting the phosphor layer. A plurality of opening holes respectively facing to the electron emission element are formed on a grid 24 provided between the first substrate and the second substrate, and a plurality of conductive members 30a respectively abutting on the partitioned layer of the metal back layer are vertically arranged. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flat panel display device including substrates disposed opposite to each other and electron-emitting devices disposed between the substrates.

  In recent years, as a next-generation flat display device, development of a flat-type flat display device in which a large number of electron-emitting devices are arranged and opposed to a phosphor screen has been advanced. There are various types of electron-emitting devices, all of which basically use field emission, and display devices using these electron-emitting devices are generally called field emission displays (hereinafter referred to as FED). )is called. A display device using a surface conduction electron-emitting device among FEDs is also called a surface conduction electron-emitting display (hereinafter referred to as SED).

The FED generally has a first substrate and a second substrate that are arranged to face each other with a predetermined gap, and these substrates are connected to each other through a rectangular frame-shaped side wall and bonded to each other in a vacuum outside. It constitutes an envelope. The inside of the vacuum vessel is maintained at a high vacuum with a degree of vacuum of about 10 ⁻⁴ Pa or less. Further, in order to support an atmospheric pressure load applied to the first and second substrates, a plurality of support members are disposed between these substrates.

  A phosphor surface including red, green, and blue phosphor layers is formed on the inner surface of the first substrate, and a plurality of electron-emitting devices that emit electrons that excite the phosphor to emit light are formed on the inner surface of the second substrate. Is provided. In addition, a large number of scanning lines and signal lines are formed in a matrix on the inner surface of the second substrate and connected to each electron-emitting device. An anode voltage is applied to the phosphor screen, and the electron beam emitted from the electron-emitting device is accelerated by the anode voltage and collides with the phosphor screen, whereby the phosphor emits light and an image is displayed.

  In such an FED, the gap between the first substrate and the second substrate can be set to several mm or less, and it is lighter than a cathode ray tube (CRT) used as a display of a current television or computer. And thickness reduction can be achieved.

  In order to obtain practical display characteristics in the FED configured as described above, a phosphor similar to a normal cathode ray tube was used, and an aluminum thin film called a metal back layer was formed on the phosphor. It is necessary to use a fluorescent screen. In this case, it is desirable that the anode voltage applied to the phosphor screen through the metal back layer is at least several kV, preferably 10 kV or more.

  However, the gap between the first substrate and the second substrate cannot be made too large from the viewpoint of resolution, spacer characteristics, etc., and needs to be set to about 1 to 2 mm. Therefore, in the FED, it is inevitable that a strong electric field is formed in a small gap between the first substrate and the second substrate, and discharge between the two substrates becomes a problem.

  If no measures are taken for suppressing discharge damage, the discharge causes destruction or deterioration of the electron-emitting device, the thin film electrode connected thereto, the phosphor screen, the driver IC, and the drive circuit. These are collectively called discharge damage. In a situation where such damage occurs, in order to put the FED into practical use, it is necessary to prevent discharge from occurring for a long period of time. However, this is very difficult to achieve.

Therefore, it is important to take measures to reduce the discharge current so that even if discharge occurs, discharge damage does not occur or can be suppressed to a negligible level. As a technique for this purpose, a technique is disclosed in which a notch is formed in a metal back layer provided on the phosphor screen to form a zigzag pattern or the like to increase the effective impedance of the phosphor screen (for example, Patent Document 1). ). Moreover, the technique which applies a high voltage by dividing | segmenting a metal back layer and connecting with a common electrode through a resistance member is disclosed (for example, patent document 2). Furthermore, a technique is disclosed in which the metal back layer is divided or patterned and a resistive material is used for the metal back layer (for example, Patent Document 3).
JP 2000-31642 A Japanese Patent Laid-Open No. 10-326583 JP 2003-242911 A

  As described above, by dividing the metal back layer into a plurality of regions and dividing the capacitance, damage to the electron-emitting device and the metal back layer due to discharge can be reduced. However, in order to apply the anode voltage to the capacity-divided metal back layer, it is necessary to provide means for supplying the anode voltage in a state where the capacity division of the metal back layer is maintained. In addition, the metal back layer itself is a very thin metal film, and it is difficult to control the voltage with the metal back layer, and if the divided layer of the metal back layer is damaged, a sufficient voltage may not be applied to the divided layer. There is.

  When wiring for supplying voltage to the division layer of the metal back layer is provided on the first substrate, the effective display area in which the phosphor layer is formed is reduced by this wiring, and the entire device including the resistance value of the wiring There are problems such as complicated design, a step of forming a wiring, and an increase in manufacturing steps and a decrease in manufacturing yield.

  The present invention has been made in view of the above points, and an object of the present invention is to suppress the occurrence of discharge and to stably apply a desired voltage to the metal back layer, thereby improving reliability and display quality. An object of the present invention is to provide a flat display device with improved performance.

  In order to achieve the above object, a flat display device according to an aspect of the present invention includes a phosphor screen including a phosphor layer, a plurality of layers that are provided on the phosphor screen in an overlapping manner, and are electrically separated. A first substrate on which a metal back layer having a divided layer is formed; and a phosphor excitation means for exciting the phosphor layer while being disposed opposite to the first substrate with a predetermined gap. A plate-like grid provided between the first substrate and the second substrate, and having a plurality of apertures facing the phosphor excitation means, and standing on the grid. And a plurality of conductive members in contact with the divided layers of the metal back layer.

  According to the present invention, by dividing the metal back layer into a plurality of divided layers and dividing the capacitance, the discharge scale can be suppressed, and a desired voltage can be stably applied to each divided layer via the conductive member. can do. Thereby, a flat display device with improved reliability and display quality can be obtained.

Hereinafter, embodiments in which the present invention is applied to an SED which is a kind of FED as a flat 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. Corresponding arrangement. The first substrate 10 and the second substrate 12 have a flat rectangular shape in which peripheral portions are bonded to each other through a rectangular frame-shaped side wall 14 made of glass, and the inside is maintained at a high vacuum of about 10 ⁻⁴ Pa or less. A vacuum envelope 15 is configured. 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. As will be described later, the phosphor screen 16 includes phosphor layers R, G, and B that emit red, green, and blue light and a matrix-shaped light shielding layer. On the phosphor screen 16, for example, a metal back layer 17 mainly composed of aluminum is 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 sources for exciting the phosphor layers R, G, and B of the phosphor screen 16. . These electron-emitting devices 18 are arranged in a plurality of columns and a plurality of rows corresponding to each pixel. 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. When the longitudinal direction of the first substrate 10 is the first direction X and the width direction orthogonal thereto is the second direction Y, the wiring 21 is a plurality of scanning wirings extending in parallel with each other along the first direction X. And signal wirings extending in parallel with each other along the second direction Y.

  As shown in FIGS. 3 and 4, in the phosphor screen 16 provided on the inner surface of the first substrate 10, the phosphor layers R, G, and B are each formed in a rectangular shape. The phosphor layers R, G, and B are alternately arranged with a predetermined gap in the first direction X, and the phosphor layers of the same color are arranged with a predetermined gap in the second direction. The phosphor layers R, G, and B are arranged at the same pitch as the electron-emitting devices 18 in the first direction X and the second direction Y. The phosphor screen 16 has a black light shielding layer 11, which is a rectangular frame portion 11 a extending along the peripheral edge of the first substrate 10, and phosphor layers R and G inside the frame portion. , B has a matrix portion 11b extending in a matrix.

  The metal back layer 17 is formed so as to overlap the phosphor layers R, G, and B. The metal back layer 17 has a plurality of divided layers 17a that are separated from each other and electrically independent. The divided layers 17a are each formed in a band shape and extend in the first direction X. Each divided layer 17a is provided, for example, so as to overlap two adjacent phosphor layer columns extending in the first direction X and one row of matrix portions 11b located between these phosphor layer columns. The divided layers 17a are arranged in the second direction Y with a gap between the matrix portions 11b for one row.

  A common wiring 23 is formed so as to overlap the frame portion 11 a of the light shielding layer 11, and extends along the second direction Y. The common wiring 23 is formed, for example, by screen printing silver paste. The common wiring 23 is provided adjacent to one end of the divided layer 17a. One end of each divided layer 17 a is connected to the common wiring 23 via the connection resistor 25. The connection resistance 25 has a higher resistance value than the divided layer 17a.

  In the present invention, the term “metal back layer” is used. However, this layer is not limited to metal, and various materials can be used. However, in this application, the term metal back layer is used for convenience.

  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. In the present embodiment, the spacer structure 22 includes a grid 24 made of a rectangular metal plate, and a large number of columnar spacers standing upright on both sides of the grid.

  More specifically, the grid 24 has a first surface 24a facing the inner surface of the first substrate 10 and a second surface 24b facing the inner surface of the second substrate 12, and is arranged in parallel to these substrates. A large number of electron beam passage holes 26 are formed in the grid 24 by etching or the like. The electron beam passage holes 26 are arranged at the same pitch as the electron-emitting devices 18 in the first direction X and the second direction Y, and face the electron-emitting devices 18 respectively. Thereby, each electron beam passage hole 26 transmits the electron beam emitted from the corresponding electron emitting element 18. Each electron beam passage hole 26 is formed in a rectangular shape of 0.22 × 0.18 mm, for example. The grid 24 is formed to a thickness of 0.12 mm by, for example, an iron-nickel metal plate. The second surface 24b of the grid 24 is covered with an insulating layer 32 made of, for example, frit glass and having a thickness of 30 μm as an insulating material.

  A plurality of first spacers 30 a are integrally provided on the first surface 24 a of the grid 24, and are positioned between adjacent electron beam passage holes 26. The tip of the first spacer 30 a is in contact with the inner surface of the first substrate 10 via the divided layer 17 a of the metal back layer and the matrix portion 11 b of the light shielding layer 11. A plurality of first spacers 30a aligned with a gap in the first direction X are in contact with one divided layer 17a.

  A plurality of second spacers 30 b are integrally provided on the second surface 24 b of the grid 24, and are positioned between adjacent electron beam passage holes 26. The tip of the second spacer 30 b is in contact with the inner surface of the second substrate 12 via the wiring 21. The first and second spacers 30a and 30b are aligned with each other, and are formed integrally with the grid 24 with the grid 24 sandwiched from both sides.

  In the first direction X and the second direction Y, the first and second spacers 30 a and 30 b are arranged at a pitch several times that of the electron-emitting devices 18. Each of the first and second spacers 30a and 30b is formed in a tapered shape with a diameter decreasing from the grid 24 side toward the extending end. The first spacer 30a has a substantially elliptical cross-sectional shape and a height of about 0.6 mm. Each second spacer 30b has a substantially elliptical cross-sectional shape and a height of about 0.8 mm.

At least a plurality of the first spacers 30a are here, and at least a plurality of the first spacers 30a that are in contact with one divided layer 17a are mainly composed of glass, and a metal oxide such as ruthenium oxide. The electroconductive member which is formed with the material containing this and has electroconductivity is comprised. The other first spacers 30a are made of a material mainly containing glass and not containing metal oxide. The resistance value between the end of the first spacer 30a constituting the conductive member that is in contact with the first substrate 10 and the end on the grid side is 1 × 10E11Ω or less, and is in contact with the first substrate 10 of the other first spacer. The resistance value between the end and the grid side end is 1 × 10E13Ω or more. Thus, the plurality of first spacers 30a include at least two types of spacers having different resistances.
Each of the second spacers 30b is made of a material containing glass as a main component and not containing metal oxide, and the resistance value between the end in contact with the second substrate 12 and the grid side end is 1 × 10E13Ω or more. .

  The spacer structure 22 configured as described above is disposed between the first substrate 10 and the second substrate 12. The grid 24 is welded to a metal support member 42 erected at the corner of the first substrate 12. The first and second spacers 30a and 30b are in contact with the inner surfaces of the first substrate 10 and the second substrate 12, thereby supporting the atmospheric pressure load acting on these substrates, and the interval between the substrates being a predetermined value. To maintain. The first spacer constituting the conductive member among the first spacers 30 a is erected on the first surface 24 a of the grid 24 made of a metal plate, and the extending end thereof is the divided layer 17 a of the metal back layer 17. Abut. Thereby, these 1st spacers 30a have electrically connected the grid 24 and each division | segmentation layer 17a.

  The SED includes a power supply unit 44 that functions as a voltage supply unit. The power supply unit 44 is connected to the grid 24. The power supply unit 44 applies a desired voltage to each divided layer 17a of the metal back layer 17 through the grid 24 and the first spacer 30a. When displaying an image in the SED, an anode voltage of, for example, 10 kV is applied to the phosphor screen 16 and the metal back layer 17, and the electron beam emitted from the electron-emitting device 18 is accelerated by the anode voltage to the phosphor screen 16. Collide. As a result, the phosphor layer of the phosphor screen 16 is excited to emit light and display an image.

  According to the SED configured as described above, by dividing the metal back layer 17 into a plurality of divided layers 17a and dividing the capacitance, the discharge scale is suppressed even when a discharge occurs between the first and second substrates. can do. Further, by applying an anode voltage to each divided layer 17a of the metal back layer 17 through the conductive member formed by the grid 24 and the first spacer 30a, a voltage can be stably applied to each divided layer 17a. . At this time, since a plurality of first spacers functioning as conductive members are in contact with each divided layer 17a, an anode voltage can be reliably applied to the divided layer 17a even if the divided layer 17a is slightly damaged. It becomes. Further, it is not necessary to form wiring for applying an anode voltage on the phosphor screen, and it is possible to prevent a decrease in the effective display area and an increase in the manufacturing process due to these wirings. From the above, an SED with improved reliability and display quality can be obtained.

  The present inventors conducted various experiments on the SED having the above configuration. Due to the capacity division of the metal back layer, large-scale discharge that damages the constituent members is suppressed, the metal back layer is not damaged by a diameter of 0.05 mm or more, and the second substrate is driven. The driver was not damaged. Furthermore, the wiring short circuit of the 2nd board | substrate which 2 or more continued was lost. Since the anode voltage is supplied through the first spacer, the anode voltage can be stably applied even if there is a split portion in the divided layer of the metal back layer. In addition, by adjusting at least one of the number of first spacers or the resistance value that is in contact with the divided layer, a design that optimizes the discharge scale can be easily performed.

  Next explained is an SED according to the second embodiment of the invention. According to the present embodiment, as shown in FIGS. 5 and 6, the first and second surfaces 24 a and 24 b of the grid 24 and the inner surfaces of the electron beam passage holes 26 are formed by the insulating layer 32 made of, for example, frit glass. It is covered. A plurality of wirings 50 each extending in the first direction X are formed on the first surface 24 a of the grid 24. Further, a common wiring 52 extending in the second direction Y is formed on the first surface 24 a of the grid 24 and connected to one end of each wiring 50. The wiring 50 and the common wiring 52 are formed, for example, by applying a silver paste and baking it.

  The plurality of first spacers 30 a constituting the spacer structure 22 are integrally formed on the first surface of the grid 24 so as to overlap each other on the wiring 50. Of the first spacers 30a, the first spacers constituting the conductive member are made of a material containing glass as a main component and containing a metal oxide such as ruthenium oxide. The other first spacers 30a are made of a material containing glass as a main component and not containing metal oxide. The resistance value between the end of the first spacer 30a constituting the conductive member that is in contact with the first substrate 10 and the grid-side end is 1 × 10E11Ω or less, and the first spacer 10 of the other first spacer The resistance value between the abutted end and the grid side end is 1 × 10E13Ω or more. The first spacer 30a constituting the conductive member is erected on the wiring 50 and is electrically connected to the wiring 50, and its extended end is in contact with the divided layer 17a of the metal back layer 17. Yes. Thereby, these first spacers 30a electrically connect the wiring 50 and each divided layer 17a.

  The second spacer 30 b is erected integrally on the second surface 24 b of the grid 24. Each of the second spacers 30b is made of a material containing glass as a main component and not containing metal oxide, and the resistance value between the end in contact with the second substrate 12 and the grid side end is 1 × 10E13Ω or more. .

A power supply unit 44 that functions as a voltage supply unit is connected to a common wiring 52 on the grid 24. The power supply unit 44 applies a desired voltage to each divided layer 17a of the metal back layer 17 through the common wiring 52, the wiring 50, and the first spacer 30a. When displaying an image in the SED, an anode voltage of, for example, 10 kV is applied to the phosphor screen 16 and the metal back layer 17, and the electron beam emitted from the electron emitter 18 is accelerated by the anode voltage to accelerate the phosphor screen. Collide with 16 As a result, the phosphor layer of the phosphor screen 16 is excited to emit light and display an image.
Other configurations are the same as those of the first embodiment described above, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  Even in the second embodiment configured as described above, even if a discharge occurs between the first and second substrates by dividing the metal back layer 17 into a plurality of divided layers 17a and dividing the capacitance, the discharge scale is reduced. Can be suppressed. Further, by applying an anode voltage to each divided layer 17a of the metal back layer 17 through the wiring member 50 on the grid 24 and the conductive member formed by the first spacer 30a, a voltage is stably applied to each divided layer 17a. can do. Since each of the divided layers 17a is in contact with a plurality of first spacers that function as conductive members, it is possible to reliably apply an anode voltage to the divided layers 17a even when the divided layers 17a are slightly damaged. Further, it is not necessary to form wiring for applying an anode voltage on the phosphor screen, and it is possible to prevent a decrease in the effective display area and an increase in the manufacturing process due to these wirings. From the above, an SED with improved reliability and display quality can be obtained.

  Note that 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. In addition, various inventions can be formed by appropriately combining a plurality of components 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.

  In the embodiment described above, the spacer structure is configured to integrally include the first and second spacers and the grid, but the second spacer may be formed on the second substrate 12. 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 present invention is not limited to the use of a surface conduction electron-emitting device as an electron source, but can also be applied to a flat panel display using other electron sources such as a field emission type and 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 said SED. The top view which shows the fluorescent substance layer and metal back layer of said SED. The perspective view which fractures | ruptures and shows SED which concerns on 2nd Embodiment of this invention. Sectional drawing which expands and shows SED which concerns on 2nd Embodiment.

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 layer, 17a ... divided layer,
18 ... Electron emitting device, 22 ... Spacer structure, 24 ... Grid,
26 ... Electron beam passage hole, 30a ... First spacer, 30b ... Second spacer,
50 ... wiring, 52 ... common wiring.

Claims (10)

A first substrate on which a phosphor screen including a phosphor layer and a metal back layer provided on the phosphor screen and having a plurality of divided layers electrically separated are formed; ,
A second substrate disposed opposite to the first substrate with a predetermined gap and provided with phosphor excitation means for exciting the phosphor layer;
A plate-like grid provided between the first substrate and the second substrate and having a plurality of apertures respectively facing the phosphor excitation means;
A plurality of conductive members that are erected on the grid and are in contact with the divided layers of the metal back layer,
A flat display device. The grid is formed of a metal plate, and has a first surface facing the first substrate, and a second surface facing the second substrate and covered with an insulating layer,
A plurality of first spacers standing on the first surface of the grid and contacting the first substrate, and a plurality of second spacers standing on the second surface of the grid and contacting the second substrate, respectively. The flat display device according to claim 1, wherein at least a plurality of the first spacers constitute the conductive member.   The flat display device according to claim 1, further comprising a voltage supply unit that supplies an anode voltage from the grid to the first substrate through the conductive member. The grid is formed of a metal plate and is opposed to the first substrate and covered with an insulating layer, and the second surface is opposed to the second substrate and covered with an insulating layer. A plurality of wirings formed on the first surface,
A plurality of first spacers each standing on the first surface of the grid and in contact with the first substrate and electrically connected to the wiring, and each of the first spacers standing on the second surface of the grid. The flat display device according to claim 1, further comprising a plurality of second spacers in contact with the two substrates, wherein at least a plurality of the first spacers constitute the conductive member.   5. The flat display device according to claim 1, further comprising a voltage supply unit configured to supply an anode voltage from the wiring to the first substrate through the conductive member.   The resistance value between the end of the first spacer constituting the conductive member in contact with the first substrate and the grid side end is 1 × 10E11Ω or less, and the end of the second spacer in contact with the second substrate and the grid The flat display device according to claim 2, wherein a resistance value between the side ends is 1 × 10E13Ω or more.   The first spacer includes at least two types of spacers, a spacer having a resistance value of 1 × 10E11Ω or less and a spacer having a resistance of 1 × 10E13Ω or more between an end in contact with the first substrate and a grid side end. The flat display device according to claim 6. The phosphor screen includes a plurality of color phosphor layers arranged with a gap along a first direction and a first direction orthogonal to the first direction, and a light shielding layer formed between the adjacent phosphor layers. Including,
The divided layers of the metal back layer are each formed in a strip shape and are arranged with a gap therebetween, and are provided so as to overlap a plurality of phosphor layers and a light shielding layer positioned between the phosphor layers. The flat display device according to any one of the above.   The flat display device according to claim 8, wherein the conductive member is in contact with the divided layer at a position facing the light shielding layer. The phosphor excitation means includes a plurality of electron-emitting devices arranged on the second substrate, and a plurality of scanning lines provided parallel to each other on the second substrate and supplying a potential to the electron-emitting devices. Have
10. The flat display device according to claim 1, wherein each of the divided layers of the metal back layer extends in parallel with the scanning line.

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