JP2005259517A - Display device - Google Patents

Abstract

An object of the present invention is to provide a display device capable of effectively suppressing luminance unevenness with an inexpensive configuration.
A SED includes a front substrate 10 having a phosphor layer, a rear substrate 12 having an electron-emitting device, and a side wall 14 for sealing a peripheral portion of the substrate, and a vacuum envelope having a vacuum inside. Have. A matrix-like wiring 21 connecting a plurality of electron-emitting devices includes a first portion 41 extending in the image display area and a second portion 42 outside the image display area. The first portion 41 is formed by printing a metal paste, and the electric resistance is set to 100 [Ω / m] or less, thereby suppressing luminance unevenness. The second portion 42 is densely formed by depositing a metal material, ensuring the sealing performance of the sealing portion and improving the reliability.
[Selection] Figure 5

Description

  The present invention has a flat envelope having a flat panel structure, and emits electrons from an electron-emitting device provided on a back substrate to display a color image by exciting and emitting a phosphor layer provided on the front substrate. The present invention relates to a display device.

  In recent years, field emission displays (FEDs), plasma displays (PDPs), and the like are known as display devices having a vacuum envelope with a flat flat panel structure. In addition, as a kind of FED, a display device (hereinafter referred to as SED) including a surface conduction electron-emitting device has been developed.

  The SED has a front substrate and a rear substrate that are opposed to each other with a predetermined gap. These substrates are joined to each other at peripheral edges via rectangular frame-shaped side walls, and the inside is evacuated to form a flat envelope having a flat panel structure.

  A phosphor layer of three colors is formed on the inner surface of the front substrate, and on the inner surface of the rear substrate, a large number of electron-emitting devices corresponding to each pixel are arranged as an electron emission source for exciting and emitting the phosphor layer. ing. A large number of wires for driving the electron-emitting devices are provided in a matrix on the inner surface of the rear substrate, and the end portions are drawn out of the vacuum envelope.

  A plate-like grid is disposed between the front substrate and the rear substrate. In this grid, a plurality of beam passage holes are formed in a positional relationship aligned with the electron-emitting devices, and a plurality of holes for maintaining a gap between the substrates by contacting the inner surfaces of the front substrate and the rear substrate. Columnar spacers are provided.

  When this SED is operated, a drive voltage is selectively applied to each electron-emitting device via a drive circuit connected to the wiring. Thereby, an electron beam is selectively emitted from each electron-emitting device, and these electron beams are irradiated to the corresponding phosphor layer through the corresponding beam passage hole of the grid, and the phosphor layer is excited and emitted. An image is displayed.

  In this SED, the electrons emitted from the electron-emitting device to the phosphor layer are only a few electrons flowing between the electron-emitting devices. In order to perform electron beam irradiation sufficient for image display, 1 to 10 mA. It is necessary to pass a large current through the wiring. For this reason, in the wiring part, a voltage drop occurs due to the wiring resistance and the above-described large current, and luminance spots due to the voltage drop occur. For this reason, the SED wiring is formed by a thick print paste wiring in order to reduce the resistance. However, since such paste wiring is thick and porous, it is difficult to maintain the hermeticity of the sealing portion, and the durability of the connection portion to the drive circuit is also deteriorated.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a display device that ensures reliability while suppressing luminance unevenness with an inexpensive configuration.

In order to achieve the above object, a display device of the present invention includes a back substrate having a plurality of wirings formed in a matrix in an insulated state and a plurality of electron-emitting devices respectively provided at intersections thereof, and the back substrate And a front substrate having a plurality of display pixels corresponding to the plurality of electron-emitting devices. And the electrical resistance of the first portion provided in the image display region inside the sealing portion of the rear substrate and the front substrate of the wiring extending in at least one direction among the wiring formed in the matrix shape Is 100 [Ω / m] or less, and at least the wiring of the sealing portion following the first portion and the wiring outside the sealing portion are formed by film formation of a metal material. ing According to the above invention, the electrical resistance of the first portion of the wiring in the image display area can be sufficiently reduced, and at least the voltage drop in the wiring portion extending in the image display area can be suppressed to a desired level. And luminance spots caused by voltage drop can be effectively suppressed. Further, since the wiring of the sealing part and the wiring outside the sealing part are formed not by extending the first portion but by forming a metal material, at least the wiring of the sealing part is formed. The wiring can be made thinner and denser than the first part, and a highly reliable sealing can be realized. Further, by forming the wiring outside the sealing portion with a dense structure, it is possible to increase the reliability when the driving circuit is pressure-bonded to the wiring portion via the anisotropic conductive film.

  Further, the display device of the present invention includes a back substrate having a plurality of wirings formed in a matrix in an insulated state and a plurality of electron-emitting devices provided at intersections thereof, and spaced apart from the back substrate. A vacuum envelope comprising: a front substrate having a plurality of display pixels corresponding to the plurality of electron-emitting devices; The electrical resistance of the first portion provided in the image display area inside the sealing portion of the back substrate and the front substrate of the wiring extending in at least one direction among the wirings formed in a matrix is 100 [Ω / m] or less, and the second portion outside the first portion outside the image display area is formed by film formation of a metal material.

  Further, the display device of the present invention includes a back substrate having a plurality of wirings formed in a matrix in an insulated state and a plurality of electron-emitting devices provided at intersections thereof, and a back substrate spaced apart from the back substrate. A vacuum envelope comprising: a front substrate having a plurality of display pixels corresponding to the plurality of electron-emitting devices; The electrical resistance of the first portion provided in the image display area inside the sealing portion of the back substrate and the front substrate of the wiring extending in at least one direction among the wirings formed in a matrix is 100 [Ω / m] or less, and the second portion outside the first portion outside the image display region is formed thinner than the first portion by a material different from the first portion.

  Since the display device of the present invention has the above-described configuration and operation, reliability can be ensured while suppressing luminance unevenness with an inexpensive configuration.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, an SED will be described as an example of a display device according to an embodiment of the present invention.

  As shown in FIGS. 1 to 3, the SED 1 includes a front substrate 10 and a rear substrate 12 each made of a rectangular glass plate, and these substrates are arranged to face each other with a gap of about 1.0 to 2.0 mm. Has been. The front substrate 10 and the rear substrate 12 are joined together via a rectangular frame-shaped side wall 14 made of glass, and constitute a vacuum envelope 15 having a flat flat panel structure with a vacuum inside. .

  A phosphor screen 16 that functions as an image display surface is formed on the inner surface of the front substrate 10. The phosphor screen 16 is configured by arranging red, blue, and green phosphor layers R, G, and B, and a light shielding layer 11, and these phosphor layers are formed in stripes or dots. A metal back 17 made of aluminum or the like is formed on the phosphor screen 16.

  On the inner surface of the rear substrate 12, a number of surface-conduction electron-emitting elements 18 that emit electron beams are provided as electron emission sources that emit electrons for exciting and emitting the phosphor layer of the phosphor screen 16. ing. 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. Further, on the inner surface of the back substrate 12, a large number of wirings 21 for applying a driving voltage to the respective electron-emitting devices 18 are provided in a matrix shape, and end portions thereof are drawn out of the vacuum envelope 15. Yes.

  The side wall 14 functioning as a bonding member is sealed to the peripheral edge of the front substrate 10 and the peripheral edge of the rear substrate 12 by, for example, a sealing material 20 such as low melting glass or low melting metal, and these substrates are joined together. doing. In the present embodiment, the back substrate 12 and the side wall 14 are bonded using frit glass, and the front substrate 10 and the side wall 14 are bonded using indium. If the space between the back substrate 12 where the wiring 21 is located and the side wall 14 is sealed with a low melting point metal, an insulating layer is provided as an intermediate layer in order to avoid an electrical short between the wiring 21 and the sealing material 20.

  As shown in FIGS. 2 to 4, the SED 1 includes a spacer structure 22 disposed between the front substrate 10 and the rear substrate 12. In the present embodiment, the spacer structure 22 is composed of a grid 24 made of a rectangular metal plate, and a large number of columnar spacers 30 standing integrally on both sides of the grid.

  The grid 24 has a first surface 24 a that faces the inner surface of the front substrate 10 and a second surface 24 b that faces the inner surface of the rear substrate 12, and is arranged in parallel with 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 apertures 26 are respectively arranged to face the electron emission elements 18 and allow the electron beams emitted from the electron emission elements to pass therethrough.

  On the first surface 24 a of the grid 24, a first spacer 30 a is integrally provided so as to be positioned between adjacent electron beam passage holes 26. The extending end of the first spacer 30 a is in contact with the inner surface of the front substrate 10 via the metal back 17 and the light shielding layer 11 of the phosphor screen 16. Further, on the second surface 24 b of the grid 24, a second spacer 30 b is integrally provided so as to be positioned between the adjacent electron beam passage holes 26. The extending end of the second spacer 30 b is in contact with the wiring 21 provided on the inner surface of the back substrate 12.

  The spacer structure 22 configured as described above is disposed between the front substrate 10 and the rear substrate 12, and the first and second spacers 30a and 30b are brought into contact with the inner surfaces of the front substrate 10 and the rear substrate 12, respectively. Thus, the atmospheric pressure load acting on these substrates is supported, and the interval between the substrates is maintained at a predetermined value.

  The SED 1 includes a voltage supply unit (not shown) that applies a voltage to the grid 24 and the metal back 17 of the front substrate 10. For example, a voltage of 12 kV is applied to the grid 24 and a voltage of 10 kV is applied to the metal back 17.

  In the SED 1, when displaying an image, a voltage is applied between the device electrodes of the electron-emitting device 18 through the wiring 21 to emit an electron beam from the electron-emitting portion of the arbitrary electron-emitting device 18, and phosphor An anode voltage is applied to the screen 16 and the metal back 17. The electron beam emitted from the electron emission portion is accelerated by the anode voltage, passes through the electron beam passage hole 26 of the grid 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.

  When manufacturing the SED 1 having the above structure, the front substrate 10 provided with the phosphor screen 16 and the metal back 17, the back substrate 12 provided with the electron-emitting devices 18 and the wirings 21, and the side walls 14 are bonded in advance. And prepare. In addition, a spacer structure 22 in which a large number of spacers 30a and 30b are provided on the grid 24 is prepared.

  Then, the spacer structure 22 is positioned on the back substrate 12. In this state, the front substrate 10, the rear substrate 12, and the spacer structure 22 are arranged in a vacuum chamber (not shown), the inside of the vacuum chamber is evacuated, and then the front substrate is bonded to the rear substrate via the side wall 14. Thereby, SED1 provided with the spacer structure 22 is manufactured.

  In the SED 1 described above, a very small amount of electrons emitted from the electron-emitting device 18 are irradiated on the phosphor screen 16, and most of them flow through the wiring 21 as they are. For this reason, a great amount of current flows in the wiring 21 (especially scanning wiring that performs line sequential scanning), and the problem of unevenness in brightness due to a voltage drop based on the electrical resistance of the wiring 21 becomes significant. In other words, a region farther from the drive driver (the center of the screen) cannot provide a sufficient voltage due to a voltage drop, the amount of emitted electrons is reduced, and electrons that irradiate the phosphor layers R, G, and B are reduced. The brightness of the phosphor layer decreases. In order to prevent such brightness unevenness, in this embodiment, the wiring 21 is formed of a thick print paste, and the electric resistance is sufficiently lowered to suppress the voltage drop of the wiring 21. When forming a low-resistance wiring with a thick film in this way, it is ideally formed with a dense metal. However, with such a wiring, a substrate (generally glass and having a lower thermal expansion coefficient than that of metal). ) And the thermal expansion coefficient difference causes problems such as peeling disconnection during manufacturing. For this reason, a paste in which frit glass and metal powder are mixed with a solvent is used, and the substrate and metal powder are fixed with frit glass. With this type of wiring, a thick film wiring of 5 μm or more can be formed, and the wiring resistance can be set to 100 [Ω / m] or less. In particular, the SED 1 has a large current of about 1 to 10 [mA] in the wiring 21 as compared with other display panels such as FED and PDP. Can be suppressed.

  Specifically, in the present embodiment, as shown in FIG. 5, the wiring 21 is extended to the image display area inside the sealing portion where the rear substrate 12 and the front substrate 10 are sealed via the side wall 14. The electric resistance of the portion (hereinafter, this portion is referred to as the first portion 41) was set to 100 [Ω / m] or less. By setting the electrical resistance of the first portion 41 to this level, it is possible to prevent the luminance of the display pixel from decreasing near the center of the screen. In other words, in the SED 1 having the above-described structure, when a drive current of about 1 to 10 [mA] is passed, if the electric resistance of the first portion 41 exceeds 100 [Ω / m], the luminance unevenness of the display image is slight. While confirmed. That is, by setting the electric resistance of the first portion 41 to 100 [Ω / m] or less, it is possible to obtain a sufficiently low electric resistance without causing luminance spots.

  In the present embodiment, in order to realize the above-described electrical resistance, the first portion 41 of the wiring 21 is formed by a thick print paste. Specifically, a wiring having a thickness of 5 [μm] or more was formed as the first portion 41 using a metal paste in which Ag particles and frit glass were dispersed in a solvent. The metal paste is not limited to silver paste, and Al particles or Cu particles may be used, or several kinds of metal particles may be mixed and used.

  In the present embodiment, the second portion 42 of the wiring 21 outside the first portion 41 outside the image display area described above is formed by thin and dense metal material film formation. Specifically, before forming the wiring 41, a Ti film was formed on the periphery by sputtering, and this was formed into a wiring pattern by ion milling. That is, the thick film paste wiring described above is porous because it is a mixture of metal powder and frit, and when the second portion 42 is formed by the wiring having the same structure as the first portion 41, the back substrate 12 and the side wall 14 It is difficult to obtain good airtightness in the sealing portion 44 between the two and the durability of the drive circuit connection portion is also impaired. Therefore, in the present embodiment, the metal material is formed by physical vapor deposition in order to make the second portion 42 of the wiring 21 extending through the sealing portion 44 as dense as possible.

  For example, Ti, Cr, Ni, Pt, ITO, or the like can be used as a metal material for forming the second portion 42. In addition, as a film forming method of the metal material, for example, there are physical film forming such as sputtering, energization heating evaporation, high frequency heating evaporation, electron beam evaporation, or plating.

  As described above, according to the present embodiment, the first portion 41 in the image display region of the wiring 21 is formed of a material having an electric resistance of 100 [Ω / m] or less, and thus the luminance of the display device can be reduced with an inexpensive configuration. It was possible to effectively suppress the spots. In addition, according to the present embodiment, since the second portion 42 of the wiring 21 passing through the sealing portion is densely formed by film formation of a metal material different from the first portion 41, the above-described problem of luminance unevenness is solved. The high airtightness of the vacuum envelope 15 can be maintained and a more reliable display device can be provided.

  Further, according to the present embodiment, since the second portion 42 of the wiring 21 drawn out from the vacuum envelope 15 is formed by forming a dense metal material, a drive circuit (not shown) of the display device is not shown in an anisotropic conductive state. When connecting through a membrane, a good connection state can be maintained.

  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. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, you may delete some components from all the components shown by embodiment mentioned above.

  In particular, the present invention is effective when applied to a scanning line (horizontal wiring) for supplying a scanning signal to a display device, but the present invention may be applied to a signal line (vertical wiring) for supplying a video signal, The present invention may be applied to both horizontal wiring and vertical wiring.

  In the above-described embodiment, the case where the first portion 41 of the wiring 21 is formed by printing the metal paste and the second portion 42 is formed by forming the metal material has been described. The 1 portion 41 may be anything as long as the wiring resistance is reduced to the above-described level. On the other hand, it is desirable that the second portion 42 has a small film thickness. When the second portion 42 is a thick film, the sealing material does not go into the uneven corners and forms a leak path, and the drive circuit connecting portion similarly causes deterioration in durability due to collapse of the airtightness. From the viewpoint of reliability, it is desirable that the film thickness be about 5 μm or less, similar to the threshold value of the low resistance wiring described above. When the thickness is greater than this, a special composition or an airtight treatment is imposed on the sealing material or the bonded portion.

  Further, in the above-described embodiment, the case where all the wiring portions outside the image display region are formed as the second portion 42 by forming a dense metal material has been described. However, at least the back substrate 12 and the side wall 14 are formed. It is only necessary to provide a dense wiring structure only between the sealing portions. Alternatively, the wiring outside the sealing portion may be a dense wiring structure regardless of the wiring structure of the sealing portion.

1 is an external perspective view showing an SED according to an embodiment of the present invention. Sectional drawing of SED of FIG. The elements on larger scale of FIG. The perspective view which shows the spacer structure built in SED of FIG. The fragmentary sectional view of the principal part for demonstrating the wiring structure of the sealing part vicinity in SED of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... SED, 10 ... Front substrate, 11 ... Light-shielding layer, 12 ... Back substrate, 14 ... Side wall, 15 ... Vacuum envelope, 16 ... Phosphor screen, 17 ... Metal back, 18 ... Electron emission element, 21 ... Wiring , 22 ... spacer structure, 41 ... first part, 42 ... second part, 44 ... sealing part.

Claims (11)

A back substrate having a plurality of wirings formed in a matrix in an insulated state and a plurality of electron-emitting devices provided at intersections thereof, and a peripheral portion of the back substrate disposed so as to face and separate from the back substrate A front substrate having a plurality of display pixels corresponding to the plurality of electron-emitting devices, the inside of which is evacuated, and a display device having a vacuum envelope comprising:
The electrical resistance of the first portion provided in the image display area inside the sealing portion of the rear substrate and the front substrate of the wiring extending in at least one direction among the wiring formed in the matrix is 100 [Ω. / M] or less, and among the wiring of the sealing portion following the first portion and the wiring outside the sealing portion, at least the wiring of the sealing portion is formed by film formation of a metal material. Characteristic display device.   The display device according to claim 1, wherein the first portion is formed by printing a metal paste.   The display device according to claim 2, wherein the metal paste includes at least one metal material of Ag, Al, and Cu.   The display device according to claim 1, wherein the wiring of the sealing portion is formed by sputtering, vapor deposition, or plating of a metal material such as Ti, Cr, Ni, Pt, or ITO.   The display device according to claim 1, wherein a film thickness of the wiring of the sealing portion is thinner than that of the first portion.   6. The display device according to claim 5, wherein the thickness of the first portion is 5 [μm] or more, and the film thickness of the wiring of the sealing portion is less than 5 [μm].   The display device according to claim 1, wherein a driving circuit is attached to the wiring outside the sealing portion by pressure bonding through an anisotropic conductive film. A back substrate having a plurality of wirings formed in a matrix in an insulated state and a plurality of electron-emitting devices provided at intersections thereof, and a peripheral portion of the back substrate disposed so as to face and separate from the back substrate A front substrate having a plurality of display pixels corresponding to the plurality of electron-emitting devices, the inside of which is evacuated, and a display device having a vacuum envelope comprising:
The electrical resistance of the first portion provided in the image display area inside the sealing portion of the rear substrate and the front substrate of the wiring extending in at least one direction among the wiring formed in the matrix is 100 [Ω. / M], and the second portion outside the first portion outside the image display area is formed by film formation of a metal material. A back substrate having a plurality of wirings formed in a matrix in an insulated state and a plurality of electron-emitting devices provided at intersections thereof, and a peripheral portion of the back substrate disposed so as to face and separate from the back substrate A front substrate having a plurality of display pixels corresponding to the plurality of electron-emitting devices, the inside of which is evacuated, and a display device having a vacuum envelope comprising:
The electrical resistance of the first portion provided in the image display area inside the sealing portion of the rear substrate and the front substrate of the wiring extending in at least one direction among the wiring formed in the matrix is 100 [Ω. / M], and the second portion outside the first portion outside the image display area is formed thinner than the first portion by a material different from that of the first portion. .   10. The display device according to claim 1, wherein a current of 1 to 10 [mA] flows through the wiring.   The display device according to claim 1, wherein the electron-emitting device is a surface conduction electron-emitting device.

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