JP2005093100A - Flat-plate image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a production process in a flat-plate image display device having an electron beam source of an IPG(In-Plane-Gate) structure, and to improve its yield ratio and to significantly lower the manufacturing cost. <P>SOLUTION: In a manufacturing process of each component electrode, a cathode K up to a first control electrode G1 are made on a back-face substrate SUB1 through a printing process, a plate-like second control electrode structure G2' is made with a top-part insulating layer IS2 on the first control electrode G1 and a second control electrode G2 as separate components, and a negative electrode K up to the first control electrode G1 are jointed for installation on the back-face substrate 1 produced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flat-panel image display apparatus having an electron beam source having an electron source (cathode) that emits electrons by an electric field, and a phosphor screen excited by an electron beam emitted from the electron beam source. The present invention relates to a flat-panel image display device that enables high-definition image display by focusing an electron beam on a fluorescent screen.

  2. Description of the Related Art In recent years, field emission type flat panel image display devices using diamond, carbon nanotubes (also referred to as carbon nanotubes) or the like as electron sources that emit electrons in a low electric field have been developed. Hereinafter, the electron source is also referred to as a cathode. This type of cathode can obtain sufficient electron emission at a very low electric field as compared with a field emission type cathode using a conventional metal material as a main material. A flat-panel image display device using such an electron emitting material as a cathode is disclosed in, for example, “Patent Document 1” and “Patent Document 2”.

  The flat-panel image display devices described in Patent Document 1 and Patent Document 2 are so-called plane arrangements in which an electron beam source including a cathode and a control electrode is formed on the same main surface of a rear substrate as a first substrate. Each of a back panel having a structure (In-Plane Gate (hereinafter referred to as IPG)) and a front panel having a phosphor surface in which a main surface of a front substrate as a second substrate is coated with a phosphor. This is a kind of cathode ray tube in which the main surfaces are opposed, the periphery is sealed with a sealing frame, and the inside of the sealing is evacuated.

  In a flat-panel image display apparatus having an electron beam source with an IPG structure, it is effective to provide a focusing electrode in order to excite the phosphor efficiently with an electron beam from the electron beam source. When a focusing electrode is provided on a back substrate having an IPG structure, it is necessary to provide a focusing electrode wiring (also referred to as a focusing electrode line) in addition to a control electrode wiring (also referred to as a control electrode line) that supplies power to the control electrode.

In addition, “Patent Document 3” has an electron beam source composed of an electron source having a Spint structure and a control electrode, and a partition-like focusing electrode surrounding each pixel region on the electron beam source. Further, a flat panel image display device connected to the focusing electrode and a control electrode line of a pixel adjacent to the focusing electrode is disclosed.
JP 2000-268706 A JP 2002-25478 PR JP 2000-3664 PR

  In the above-described background art, in this type of IPG type flat-panel image display device, various electrodes that are stacked on the back substrate are usually formed by being stacked by a manufacturing process using a thick film printing method. . In the formation of a flat-panel image display device by the thick film printing method, it is necessary to repeatedly perform a printing process and a baking process a plurality of times alternately, and a cathode (cathode) exists in a relatively lower layer. In the printing process, it is necessary that the printing / firing process has already been completed prior to the insulating layer interposed between the control electrode and the focusing electrode and the printing / firing process of the focusing electrode.

  However, since the cathode, which is an electron source, is formed by containing carbon nanotubes (CNT), the heat resistance against the heating process is extremely weak and the electron emission characteristics are deteriorated. In order to avoid such a heating process, it is desirable to print the CNT paste at the stage where the printing process from the cathode to the focusing electrode and the baking process are completed. However, in this process, after the layers up to the focusing electrode are formed, it is necessary to avoid the occurrence of a short circuit at a lower part and to apply stable thick film printing in the height (thickness) direction. There was a problem that it was difficult.

  Also, in the printing process, due to the influence of liquid dripping due to printing application, the design flexibility such as the thickness of the insulating layer and the opening diameter of the focusing electrode between the control electrode and the focusing electrode is reduced, and the focusing is reduced. There was a problem that the electrical characteristics of the electrode could not be fully exhibited.

  The problem of the background art is that in the production process of each constituent electrode, the control electrode to the cathode layer are manufactured by a printing process, and the insulating layer and the focusing electrode between the control electrode and the focusing electrode are manufactured as separate plate-like parts. However, the problem of the background art can be solved by joining the two.

  According to the present invention, in the above configuration, the cathode is made of an electron emission material that directly emits electrons in a vacuum, and the electron emission material is any one of carbon nanotubes mainly composed of carbon, fine carbon fiber, diamond, and diamond-like carbon. It can be.

  It should be noted that the present invention is not limited to the above-described configurations and the configurations described in the embodiments described later, and it goes without saying that various modifications can be made without departing from the technical idea of the present invention. .

  According to the first aspect of the present invention, a plate-like upper insulating layer having a second control electrode formed on the upper surface is installed on the upper surface of the cathode and the first control electrode formed on the back substrate. Since the process can be simplified, it is possible to obtain extremely excellent effects such as an improvement in yield and, as a result, production costs can be greatly reduced.

  Further, according to the inventions according to claim 2 and claim 3, any one of carbon nanotubes mainly composed of carbon, fine carbon fibers, diamond, and diamond-like carbon as an electron emission material that emits electrons directly into a vacuum in a cathode. By using, there is no need for an extra heating process in the manufacturing process, so that it is possible to obtain an extremely excellent effect that the deterioration of the electron emission characteristics of the cathode can be prevented.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a cross-sectional view of an essential part for explaining the configuration of an embodiment of a flat image display device according to the present invention. In FIG. 1, reference numeral SUB1 is a back substrate, G1 is a first control electrode, G1L is a first control electrode line for supplying power to the first control electrode G1, IS1 is a lower insulating layer, and K is a cathode that is an electron source. (Cathode), KL is a cathode line (cathode line), IS2 is a plate-like upper insulating layer, G2 is a second control electrode (focusing electrode), AP is an ellipse formed on the second control electrode. IS2H is an electron passage opening formed in an elliptical shape in the upper insulating layer IS2, G2 ′ is an integrated second control electrode structure, SUB2 is a front substrate, BM is a black matrix, ADE is an anode, and PHS is It is a phosphor. Reference numeral P1 indicates a first plane parallel to the back substrate SUB1, and P2 indicates the second plane.

  The flat image display apparatus according to the present embodiment extends in the first direction (y direction) on the first plane P1 on the main surface of the back substrate SUB1 preferably made of glass or ceramic material. 1 has a plurality of cathode lines KL arranged in parallel in a second direction (x direction) intersecting with the first direction. On the cathode line KL, an electron source, that is, a cathode K is formed at a position corresponding to each pixel (color subpixel in the case of color display). In addition, the first control electrode G1 is arranged in parallel on the same plane as the cathode line KL, with at least the cathode K portion of the cathode line KL being sandwiched on the first plane P1. The first control electrode G1 is electrically connected to the first control electrode line G1L formed through the lower insulating layer IS1 on the lower side of the first plane P1 of the back substrate SUB1 through the lower insulating layer IS1. It is connected to the.

  In addition, the second control electrode G2 is disposed on the second plane P2 that is located above the first control electrode G1 and is parallel to the first plane P1. The second control electrode G2 is insulated from the first control electrode G1 by an upper insulating layer IS2 formed between the first control plane G1. Further, the second control electrode G2 is formed so as to cover the upper side of the first control electrode G1 with an opening AP through which the electron E passes in a portion corresponding to each pixel described above. The opening AP has a size such that the cathode K formed on the first plane P1 and a part of the first control electrode G1 adjacent to the cathode K are exposed. The upper insulating layer IS2 is formed except for the cathode K formed on the first plane P1 and a portion corresponding to a part of the first control electrode G1 adjacent to the cathode K.

  Further, an electron beam source for each pixel is formed at the intersection of the cathode line KL having the cathode K and the first control electrode line G1L. The cathode line KL has a lead line on at least one side around the back substrate SUB1, and the first control electrode line G1L connected to the first control electrode G1 leads to at least another side around the back substrate SUB1. The video signal voltage and the control voltage are respectively supplied through these lead lines. The second control electrode G2 constitutes a so-called focusing electrode, and a focusing voltage is supplied from a lead line (not shown) provided outside the display area of the front substrate described later.

  On the other hand, the front substrate SUB2 is bonded to the rear substrate SUB1 with a predetermined interval in the z direction by a sealing frame (not shown). The front substrate SUB2 is made of a translucent glass plate, and a phosphor PHS and an anode ADE partitioned by a black matrix BM are formed on the inner surface, and the back substrate SUB1 and the front substrate SUB2 are held at a predetermined interval. Thus, the inside is vacuum sealed.

  The flat-panel image display device configured as described above is manufactured by the process described below. First, the control electrode line G1L is formed on the rear substrate SUB1 by a screen printing method using a conductive paste (hereinafter referred to as a silver paste) suitable for a silver paste. Next, the lower insulating layer IS1 is formed on the entire surface of the rear substrate SUB2 on which the control electrode line G1L is formed, by a screen printing method using a dielectric paste, corresponding to a region where an image is displayed.

  The first control electrode G1 is formed on the flat lower insulating layer IS1 thus formed by screen printing using silver paste so as to be electrically connected to the control electrode line G1L. After these are fired, a cathode line KL is formed by a screen printing method using a silver paste in a region sandwiched between the first control electrodes G1 on the lower insulating layer IS1, and further about 1 μm is formed on the cathode line KL. A cathode K is formed by a screen printing method using a silver paste containing about 10% by weight of carbon nanotubes pulverized to the following size, and solidified by heating and firing. At this time, by setting the film thickness of the first control electrode G1 to about 10 μm and the film thickness of the cathode line KL and the cathode K to about 5 μm, respectively, the first control electrode G1 and the cathode as shown in FIG. The surface of K is substantially coplanar.

  On the other hand, the upper insulating layer IS2 installed on the back substrate SUB1 on which the various electrodes described above are formed and the second control electrode G2 formed on the upper surface of the upper insulating layer IS2 are manufactured by the process described below. Is done. First, the upper insulating layer IS2 is based on an insulating substrate made of, for example, glass or ceramic material, and the insulating substrate is formed from the cathode K at a portion facing each cathode K formed on the cathode line KL. A plurality of elliptical openings IS2H are formed as electron passage holes for allowing the emitted electrons E to pass toward the inner surface of the front substrate SUB2. These openings IS2H are formed by drilling by a simultaneous opening forming method at the time of forming the insulating substrate or a processing method by laser irradiation after forming the insulating substrate.

  Further, on the upper surface (front substrate side) excluding the openings IS2H formed in the insulating substrate, a second control electrode G2 for focusing and controlling the electrons E passing through the openings IS2H is shown on the anode side in FIG. As shown in the plan view of the main part viewed from above, it is formed over the entire surface. As a result, an integrated plate-like second control electrode assembly G2 ′ having each opening AP coaxially communicating with each opening IS2H formed in the insulating substrate is produced. The second control electrode G2 is formed by depositing a conductive metal material such as nickel with a thickness of about several tens of μm by vapor deposition or sputtering. The second control electrode G2 may be formed by coating and heating and baking on the upper surface of the insulating substrate in which each opening IS2H is formed by a screen printing method using a conductive paste. Since the second control electrode G2 is a single electrode that supplies a DC voltage, patterning is not necessary when the electrode is manufactured.

  As shown in FIG. 2, the second control electrode G2 is connected to a conductive spacer ISP for maintaining a predetermined distance from the opposed anode ADE. An electrical contact with a low resistance value is required between the second control electrode G2 and the conductive spacer ISP. Therefore, a metal or a material containing a metal component is used for fixing the conductive spacer ISP on the surface of the second control electrode G2. Even when the second control electrode G2 is divided into a plurality of members by this low resistance fixing material, the electrical contact between the second control electrodes G2 is maintained by fixing the conductive spacer ISP. become. As a result, the insulating substrate that forms the second control electrode G2 can be used in combination with a plurality of substrates having such a size that the dimensional system in the longitudinal direction does not deteriorate as shown in FIG. .

  The integrated second control electrode assembly G2 ′ thus manufactured has the electrode surface of the second control electrode G2 on the back substrate SUB1 on which the cathode line KL to the first control electrode G1 are manufactured. The openings AP and the cathodes K are coaxially arranged facing each other upward (front substrate SUB2 side), and are combined on the back substrate SUB1 on which each electrode is formed, and fixed by, for example, an inorganic adhesive. Installed. The second control electrode G2 formed on the upper surface of the upper insulating layer IS2 is connected to a lead line (not shown) provided outside the display area of the front substrate SUB2 arranged to be opposed to the focusing voltage. It has become.

  On the other hand, the front substrate SUB2 is bonded to the rear substrate SUB1 at a predetermined interval by a sealing frame (not shown) in the z direction. The front substrate SUB2 is preferably a translucent glass plate, and has a phosphor PHS and an anode ADE partitioned by a black matrix BM on the inner surface, and a vacuum seal is provided between the rear substrate SUB1 and the front substrate SUB2. Has been.

  In the structure of the present embodiment, the video signal voltage is supplied to the cathode line KL and the scanning signal voltage is supplied to the first control electrode G1, whereby the video signal is generated from the electron beam source formed at the intersection of the two. Electrons E corresponding to the magnitude of the voltage are taken out. The extracted electrons E are focused by the focusing voltage (DC voltage) supplied to the second control electrode G2, and are supplied with the high voltage supplied to the anode (anode electrode) ADE formed on the front substrate SUB2. Directed to the front substrate SUB2, the phosphor PHS is excited to emit light at a predetermined wavelength. In particular, when an electron beam source having an IPG structure is used, the use efficiency of the electron beam is improved, and a high-luminance image display can be obtained.

  In this IPG system, the penetration of the electric field into the cathode K by the second control electrode G2 and the anode electrode ADE is cut off by the scanning signal voltage supplied to the first control electrode G1 when it is off. In addition, by setting the first control electrode G1 and the cathode K to the same potential at the on time, it is possible to completely eliminate the influence of the potential of the first control electrode G1, so that pulse width modulation and time-division modulation are performed. By performing the above, it is possible to perform driving with less influence of variations in light emission characteristics between the pixels.

  The flat-type image display device configured as described above is formed by printing a process from the first control electrode line G1L to the lower insulating layer IS1, the cathode line KL, the cathode K, and the first control electrode G1 on the upper surface of the back substrate SUB1. On the other hand, the plate-like upper insulating layer IS2 and the second control electrode G2 are produced as separate parts by a vapor deposition and printing process or the like as the second control electrode assembly G2 ′, and the back substrate is prepared. Since the second control electrode assembly G2 ′ is formed as an independent part of the separate process by being bonded on the SUB1, an extra heating process is not added to the cathode K, and the heat resistance is improved. The cathode K mainly composed of low carbon nanotubes is not deteriorated, and the electron emission characteristics can be easily maintained. Further, since the heating process of the cathode K can be avoided, the printing application process of the cathode line KL and the cathode K performed after the formation on the second control electrode G2 becomes unnecessary.

  In addition, since the degree of freedom of the thickness of the upper insulating layer IS2 and the second control electrode G2 interposed between the first control electrode G1 and the second control electrode G2 is higher than that in the printing process, the cathode It becomes easy to achieve both convergence and driveability of the electrons E emitted from K. In addition, the degree of freedom in design that can appropriately set the thickness of the opening AP of the upper insulating layer IS2 and the second control electrode G2 existing between the first control electrode G1 and the second control electrode G2 is high. Therefore, the focusing characteristic of the second control electrode G2 can be sufficiently exhibited.

  FIG. 3 is a cross-sectional view of an essential part for explaining the configuration of another embodiment of the flat image display apparatus according to the present invention. The same parts as those in FIG. 3 is different from FIG. 1 in that the upper insulating layer IS2 constituting the second control electrode G2 ′ is formed so that the opening shape of the electron passage opening IS2H has the same dimension in the depth direction. Further, the second control electrode G2 ′ formed on the upper insulating layer IS2 is formed to extend around a part of the inner wall surface of each electron passage opening IS2H. When the second control electrode G2 ′ is formed on the second control electrode G2 ′, the inside of each electron passage opening IS2H is masked to form a conductive metal material by vapor deposition or sputtering. In the flat panel image display device configured as described above, the same effect as described above can be obtained, and the focusing characteristic by the second control electrode G2 can be further improved.

  In the embodiment described above, each electron passage opening IS2H of the upper insulating layer IS2 and each electron passage opening AP of the second control electrode G2 coaxially communicating with the electron passage opening IS2H are formed in an elliptical shape. However, the present invention is not limited to this, and even if it is formed in a circular shape, an oval shape, a rectangular shape, or different shapes that are different from each other in the surface direction of the opening, it is exactly the same as described above. An effect is obtained.

  In each of the above-described embodiments, the case where the present invention is applied to a field emission panel as a flat image display device has been described. However, the present invention is not limited to this, and a display or a receiver using the field emission panel is used. Needless to say, the same effects as described above can be obtained even when applied to the above.

It is principal part sectional drawing which shows the structure by one Example of the flat type image display apparatus by this invention. It is the top view seen from the 2nd control electrode shown in FIG. It is principal part sectional drawing which shows the structure by the other Example of the flat type image display apparatus by this invention.

Explanation of symbols

SUB1... Back substrate, K... Cathode (electron source), KL... Cathode line supplying power to cathode K (cathode line), IS1... Lower insulating layer, G1. Control electrode, G2... Second control electrode (focusing electrode), AP... Electron passing opening provided in the second control electrode, G1L... First feeding power to the first control electrode G1. Control electrode line, IS2... Upper insulating layer, IS2H... Electron passage opening provided in upper insulating layer IS2, G2 ′... Integrated second control electrode assembly, SUB2. BM ... black matrix, ADE ... anode, PHS ... phosphor, P1 ... first plane parallel to the back substrate SUB1, P2 ... first parallel to the second control electrode G2. 2 planes.

Claims (3)

A peripheral portion of a display area formed at a central portion of a back surface having at least a cathode on the main surface, a front substrate having an anode and a phosphor on the main surface, and the main surfaces of the back substrate and the front substrate. A flat panel image display device comprising a sealing frame for vacuum-sealing the inside of the bonding gap,
A first plane parallel to the main surface of the back substrate is formed to have the cathode and extend in the first direction and juxtaposed in the second direction intersecting the first direction. A plurality of cathode lines; and a first control electrode line formed on a main surface of the rear substrate and a lower layer of the first plane via a lower insulating layer, and the first control electrode line includes the first control electrode line An electron beam source comprising a first control electrode which is electrically connected through the lower insulating layer and which controls the amount of electrons extracted from the cathode adjacent to the cathode line in at least the display region; An electron beam formed on a second plane parallel to the first plane and located on the front substrate side and having an opening in a portion corresponding to the electron beam source, and taken out from the electron beam source; A second control electrode for focusing in the direction of the front substrate, and the second control A plate-like formed through the upper insulating layer, flat panel display device, characterized in that installed in the rear substrate between said electrode first control electrode.   2. The flat panel display according to claim 1, wherein the cathode has an electron emitting material that directly emits electrons in a vacuum, and the electron emitting material contains carbon as a main component. 3. The flat panel display according to claim 2, wherein the main component of the electron emission material is any one of carbon nanotubes, fine carbon fibers, diamond, and diamond-like carbon.

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