JP2007070127A - Conductive member and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Pb-free conductive joining material for fixing a spacer in a display panel of an image display device. <P>SOLUTION: The conductive joining material is formed by incorporating metallic particles of silver or copper into a transition metal element-containing phosphate-based glass, wherein one of the transition metal elements has a plurality kinds of valency. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conductive member and an image display device using the conductive member, and includes a self-luminous flat panel type image display device using electron emission into a vacuum, and more particularly, an electron source that emits electrons by field emission. Between a rear panel composed of a rear substrate, and a front panel composed of a front substrate having a plurality of color phosphor layers that emit light by excitation of electrons extracted from the rear panel and an anode serving as an electron acceleration electrode. This is suitable for an image display device including a display panel in which a plurality of spacers (also referred to as interval holding members or partition walls) are provided to hold a predetermined distance.

  Conventionally, a color cathode ray tube has been widely used as an image display device (display device) excellent in high luminance and high definition. However, with the recent improvement in image quality of information processing devices and television broadcasts, there has been an increasing demand for flat (or flat panel) image display devices that have high luminance and high definition characteristics and are lightweight and space-saving. Yes.

  As typical examples, liquid crystal display devices, plasma display devices and the like have been put into practical use. In addition, particularly capable of high brightness, an electron emission type image display device or field emission type image display device using electron emission from an electron source into a vacuum, an organic EL display characterized by low power consumption, etc. Various types of flat-type image display devices are also in practical use. Note that a plasma image display device, an electron emission image display device, or an organic EL image display device that does not require an auxiliary illumination light source is generally referred to as a self-luminous flat image display device.

  Among such self-luminous flat image display devices, field emission image display devices include C.I. A. Spindt et al., Conical electron emission structure, metal-insulator-metal (MIM) type electron emission structure, electron emission structure using electron emission phenomenon due to quantum tunnel effect (surface Also known are those having a conduction electron source, and those utilizing the electron emission phenomenon of diamond films, graphite films, nanotubes typified by carbon nanotubes, and the like.

  A display panel constituting a field emission type image display device which is an example of a self-luminous flat image display device has electrode lines (usually cathode lines, signal lines or data lines, hereinafter) having field emission type electron sources on the inner surface. Signal line) and a control panel electrode line (usually a gate line or a scan line, hereinafter referred to as a scan line) formed on a rear panel, and a multi-color phosphor layer on the inner surface facing the rear panel And a front panel including a front substrate provided with acceleration electrodes (also referred to as anode electrodes or anodes). The front substrate constituting the front panel is formed of a light transmissive material suitable for glass. An insulating material such as glass or alumina is used for the back substrate.

  A sealing frame (usually also referred to as a glass frame or a frame glass) is inserted in the bonding inner periphery of both panels, and is sealed and sealed with a sealing member. The back panel, the front panel, and the sealing The inside formed by the frame is evacuated.

  The electron source is provided in the vicinity of the intersection of the signal line and the scanning line, and the amount of electrons emitted from the electron source (including emission on / off) is controlled by the potential difference between the signal line and the scanning line. The emitted electrons are accelerated by a high voltage applied to the anode included in the front panel, and also hit the phosphor layer included in the front panel and excite this to thereby respond to the emission characteristics of the phosphor layer. Colored with colored light.

  Each electron source is paired with a corresponding phosphor layer to constitute a unit pixel. Usually, one pixel (one unit pixel of three colors of red (R), green (G), and blue (B)) ( In the case of a color pixel, the unit pixel is also referred to as a sub-pixel (sub-pixel).

A frame glass is fixed to the inner peripheral edge of the back panel and the front panel by a sealing member such as frit glass. The degree of vacuum inside the airtight container formed by the back panel, the front panel, and the frame glass is, for example, 10 ⁻⁵ to 10 ⁻⁷ Torr. In a front panel having a large display surface size, a plurality of spacers are interposed between the back panel and the front panel, and are joined and fixed by a joining member, and the two panels are held at a predetermined interval. This spacer is made of a surface of an insulating member such as glass or ceramics coated with a film having a slight conductivity, or a plate-like body formed of a member having a certain degree of conductivity. It is installed in a position that does not interfere with the operation of

  When installing spacers that maintain a predetermined distance between the back panel and the front panel, the structure prevents the electron beam trajectory from being bent by the charge-up of the spacers, and the arrangement of the spacers prevents the loss of partition walls. Various studies have been made on the structure for preventing discharge and the structure for preventing discharge.

As a joining member in the installation of such a spacer, PbO-based glass, Bi ₂ O ₃ -based glass, SiO ₂ —Bi ₂ O ₃ -based glass, soda glass, silica glass, Si, Zn, and the like described in Patent Document 1 are used. A conductive frit glass containing at least one of Al, Sn, Mg and the like is known. Patent Document 2 also discloses a circuit protection glass containing one or more selected from V ₂ O ₅ , ZnO, B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ , MgO, CaO, SrO, and BaO. It is. Patent Document 3 discloses a low-expansion glass in which a fine powder of a conductive material suitable for copper (Cu) is mixed.
JP 2001-338528 A JP-A-2-289445 JP 61-281044 A

The spacer in the display panel of the field emission type image display device has a conductivity of about 10 ^{8 to} 10 ⁹ Ω · cm in order to suppress charge-up. In order to plant and bond such a spacer between the rear panel (the rear substrate, usually a glass substrate) and the front panel (the front substrate, usually a glass substrate), A joining member (glass paste, frit glass) having a conductivity of about 10 ^{3 to} 10 ⁷ Ω · cm is required.

  In addition, this conductive member has a small difference in thermal expansion coefficient between the back substrate and the glass material constituting the front substrate, and has good wettability at a low melting point below the maximum temperature (approximately 450 ° C.) in the manufacturing process. What can be done is required.

  In addition, although what mixed Ag particle | grains widely used as an electroconductive metal particle with the PbO type | system | group glass with a favorable joining characteristic is also considered, PbO containing glass becomes unusable after the Christian year 2006 from the problem of environmental impact. There is a need to develop other alternative materials.

  An object of the present invention is to provide a novel conductive member for fixing a spacer in a display panel of an image display device, and an image display device having a spacer bonded using the conductive member.

In order to achieve the above object, the conductive member of the present invention is configured by mixing phosphate glass containing a transition metal element and silver or copper metal particles, and the transition metal element is the same element having a different valence.
The transition metal element having two or more valences is particularly preferably vanadium, niobium, tungsten, molybdenum, or iron. For example, Au metal particles are mixed in phosphate glass in which tetravalent and pentavalent vanadium are mixed.

Further, the conductive member of the present invention is a glass containing at least 55 to 75 wt% V ₂ O ₅ , 15 to 30 wt% P ₂ O ₅ , ₅ to 25 wt% BaO, and silver or copper in terms of oxide-based weight percentage. The metal particles were mixed and constituted. Another conductive member of the present invention is a glass containing at least ₅ to 50 wt% WO ₃ , 20 to 40 wt% P ₂ O ₅ , or ₅ to 25 wt% BaO in terms of oxide-based weight percentage, and silver or copper. The metal particles were mixed and constituted.

  And it is preferable that the compounding ratio of the metal particle | grains of silver or copper shall be 10 volume% or more and 50 volume% or less.

  Moreover, the image display apparatus of this invention joined and fixed the spacer using the above-mentioned electrically-conductive member.

  The valence of vanadium is mainly +4 or +5, the valence of niobium is mainly between +2 and +5, the valence of tungsten is mainly between +2 and +6, the valence of molybdenum is mainly between +4 and +6, The valence of iron mainly takes a value between +2 and +3, and each is mixed in the glass. A transition metal with a lower valence has more electrons than a transition metal with a higher valence. Since electrons are allowed to exist even in transition metals having a high valence, electrons conduct hopping conduction between an element having a high valence and an element having a low valence. The electric conductivity is determined by the ratio of elements having different valences, but generally good electric conduction is obtained at a ratio of approximately 1: 1, so the ratio of elements is 0.8 to 1.2: 0.8. Preferably it is between -1.2.

  Phosphate-based glasses containing transition metal elements and the same elements with different valences exhibit electronic conduction properties called popping conduction, and by mixing silver or copper metal particles into such glasses, contact between metal particles Even in a small state, electrical conductivity is generated by utilizing the hopping conduction of the glass interposed between the metal particles. For this reason, mixing a relatively small amount of metal particles has an effect of obtaining good electrical conductivity characteristics while maintaining the wettability of the glass. The conductive member of the present invention can also be applied as a wiring material and is free of lead (Pb), so it is environmentally friendly and can comply with RoHS regulations.

  By bonding the spacer using the conductive bonding material of the present invention and planting it between the rear substrate and the front substrate, the charge to be charged up to the spacer is absorbed on the substrate side, and high-quality image display Can be provided.

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

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1A and 1B are diagrams for explaining an example of an image display device according to the present invention. FIG. 1A is a perspective view, and FIG. 1B is cut along a line AA ′ in FIG. It is a schematic sectional drawing. In FIG. 1, a signal line (data line, cathode electrode line) CL and a scanning line (gate electrode line) GL are provided on the inner surface of the rear substrate SUB1 constituting the rear panel PNL1, and the signal line CL and the scanning line GL intersect each other. An electron source ELS is formed in the portion. A scanning line lead line (not shown) is formed at the end of the scanning line GL, and a signal line lead line (not shown) is formed at the end of the signal line CL.

  A light shielding film (black matrix) BM, an anode (metal back, anode) AD, a phosphor layer PH, and the like are formed on the inner surface of the front substrate SUB2 constituting the front panel PNL2. The rear substrate SUB1 constituting the rear panel PNL1 and the front substrate SUB2 constituting the front panel PNL2 are bonded to each other by a sealing member FGM with a sealing frame (frame glass) MFL interposed therebetween. In order to maintain the bonded gap at a predetermined value, the above-described spacer SPC is joined and planted between the back substrate SUB1 and the front substrate PNL2 with a conductive member (not shown).

  The internal space sealed by the back panel PNL1, the front panel PNL2, and the sealing frame MFL is exhausted from an exhaust pipe (not shown) provided in a part of the back panel PNL1, and is maintained in a predetermined vacuum state. These configurations will be described later.

  FIG. 2 is a schematic diagram for explaining a detailed structure of a cross section taken along the line A-A ′ of FIG. 1. FIG. 3 is an enlarged cross-sectional view of the main part of FIG. 2 and 3, FGM is a sealing member that fixes the frame glass MFL, FGS is a conductive member that joins the spacer, and AR is a display area. The same reference numerals as those in FIG. 1 correspond to the same functional parts.

  In such a configuration, the back substrate SUB1 is preferably a glass plate or a ceramic plate such as alumina, and the front substrate SUB2 is preferably a transparent glass plate. A glass substrate is usually used for the back substrate SUB1. The black matrix BM, the phosphor layer PH, and the anode AD are formed on the inner surface.

  Further, the frame glass MFL also serving as an outer frame installed at the peripheral edge between the back substrate SUB1 and the front substrate SUB2 is fixed between the back substrate SUB1 and the front substrate SUB2 via a sealing member FGM, The distance at the periphery between the back substrate SUB1 and the front substrate SUB2 is maintained at a predetermined dimension, for example, about 3 mm.

  The spacer SPC is bonded and fixed by a conductive member FGS between the scanning lines GL formed on the inner surface of the back substrate SUB1 and the anode AD on the black matrix BM formed on the inner surface of the front substrate SUB2.

  FIG. 4 is a partially cutaway perspective view illustrating an example of the overall structure of the image display apparatus of the present invention in more detail. FIG. 5 is a cross-sectional view taken along the line A-A ′ of FIG. 4. As a repetitive description, the inner surface of the rear substrate SUB1 constituting the rear panel PNL1 has a signal line CL and a scanning line GL, and an electron source is formed near the intersection of the signal line CL and the scanning line GL. . A signal line lead line CLT is formed at the end of the signal line CL, and a scan line lead line GLT is formed at the end of the scanning line GL.

  As described above, the anode AD and the phosphor layer PH are formed on the inner surface of the front substrate SUB2 constituting the front panel PNL2. The back substrate SUB1 constituting the back panel PNL1 and the front substrate SUB2 constituting the front panel PNL2 are bonded together with a sealing frame MFL interposed therebetween. As described above, in order to maintain the bonded gap at a predetermined value, a spacer SPC, preferably a glass plate or a ceramic plate, is planted between the back panel SUB1 and the front panel PNL2. FIG. 5 shows a cross section along the spacer SPC. FIG. 5 shows three spacers along the scanning line GL on the scanning line GL, but this is merely an example.

  The internal space sealed by the rear panel PNL1, the front panel PNL2, and the frame glass MFL is exhausted from an exhaust pipe EXC provided in a part of the rear panel PNL1, and is brought into a predetermined vacuum state.

  FIG. 6 is a schematic diagram illustrating a configuration example of one pixel of the image display device of the present invention. A first insulating film comprising a signal line CL constituting a lower electrode of an electron source suitable for an aluminum (Al) film on the main surface (inner surface) of the back substrate SUB1, and an anodized film obtained by anodizing aluminum of the lower electrode INS1, a second insulating film INS2 preferably made of a silicon nitride film SiN, a feeding electrode (connection electrode) ELC, a scan line GL suitable for chromium Cr, and an upper electrode constituting an electron source of a pixel connected to the scan line GL An AED is formed.

  The electron source has a signal line CL as a lower electrode, a thin film portion INS3 that forms a part of the first insulating film INS1 positioned on the lower electrode, a portion of the upper electrode AED that is laminated on the upper layer of the thin film portion INS3, Consists of. The upper electrode AED is formed to cover the scanning line GL and a part of the power supply electrode ELC. The thin film portion INS3 is a so-called tunnel film. With this configuration, a so-called diode electron source is formed.

  On the other hand, the front panel PNL2 is formed with a phosphor PH separated from adjacent pixels by a black matrix BM and an anode AD suitable for an aluminum vapor deposition film on the main surface of the front substrate SUB2 suitable for a transparent glass substrate. . The distance between the back panel PNL1 and the front panel PNL2 is about 3 to 5 mm, and this distance is maintained by the spacer SPC.

In such a configuration, when an acceleration voltage (approximately 2 to 3 kV to 10 kV, about 5 kV in FIG. 6) is applied between the upper electrode AED of the back panel PNL1 and the anode AD of the front panel PNL2, the signal line CL as the lower electrode is applied. Electrons e ⁻ corresponding to the size of the display data supplied to the light are emitted, and are radiated to the phosphor PH by the acceleration voltage, which is excited to emit light L having a predetermined frequency to the outside of the front panel PNL2. In the case of full-color display, this unit pixel is a color sub-pixel (sub-pixel), and usually one color pixel (color) with three sub-pixels of red (R), green (G), and blue (B). Pixel).

  FIG. 7 is a diagram illustrating an example of an equivalent circuit of the image display device of the present invention. A region indicated by a broken line in FIG. 7 is a display region AR. In this display region AR, n signal lines CL and m scanning lines GL are arranged so as to cross each other to form an n × m matrix. ing. Each intersection of the matrix constitutes a sub-pixel, and one unit of color (color pixel) in one group of three unit pixels (or sub-pixels: sub-pixels) “R”, “G”, “B” in the figure. Configure. The signal line CL is connected to the image signal drive circuit DDR at the signal line lead terminal CLT, and the scan line GL is connected to the scan signal drive circuit SDR at the scan line lead terminal GLT. The image signal NS is input from the external signal source to the image signal driving circuit DDR, and the scanning signal SS is similarly input to the scanning signal driving circuit SDR.

  Accordingly, a two-dimensional full-color image can be displayed by supplying an image signal to the signal line CL that intersects the scanning lines GL that are sequentially selected. By using the display panel of this configuration example, a self-luminous planar image display device with a relatively low voltage and high efficiency is realized.

Next, the spacer and its fixing structure will be described. An example of the spacer SPC of the present embodiment described with reference to FIGS. 1 to 6 is mainly composed of SiO ₂ and includes La, Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, and Ho. , Er, Tm, Yb, and a glass material molded body containing 1 to 20% by weight of at least one selected from Lu. Then, a conductive film for preventing charging is formed on the outer peripheral surface of the spacer body. In addition, it can replace with what adheres the electroconductive film for antistatic to the outer peripheral surface of a spacer main body, and can also use the material which has electroconductivity for spacer main body itself.

  The spacer SPC is substantially perpendicular to both the substrate surfaces in the display area AR formed between the back substrate SUB1 and the front substrate SUB2, and the length direction of the spacer SPC is one direction (see FIG. 7). A plurality of lines are aligned at a predetermined pitch interval so as to coincide with each other in the x direction), and the scanning lines GL are arranged at a predetermined pitch interval in a plurality of columns in the other direction intersecting the one direction (y direction in FIG. 7). Are juxtaposed on each other and joined and fixed by a conductive member FGS (see FIG. 3).

  The conductive member FGS is configured by mixing silver or copper metal particles into phosphate glass containing a transition metal element, and at least one valence of the transition metal elements is different from two or more. It was supposed to be. The transition metal element may be at least one of vanadium, niobium, tungsten, molybdenum, and iron.

In addition, the conductive member of the present invention is a glass containing at least 55 to 75 wt% V ₂ O ₅ , 15 to 30 wt% P ₂ O ₅ , ₅ to 25 wt% BaO in terms of oxide weight percentage, and silver or copper. It is configured by mixing metal particles. Another conductive member of the present invention is a glass containing at least ₅ to 50 wt% WO ₃ , 20 to 40 wt% P ₂ O ₅ , or ₅ to 25 wt% BaO in terms of oxide weight percentage, and silver or copper. It is configured by mixing metal particles.

  Then, a conductive member having a compounding ratio of silver or copper metal particles of 10 volume% or more and 50 volume% or less was obtained.

  In the image display device of the present invention, the spacer is bonded and fixed using the above-described conductive member. In this way, by setting the spacer between the back substrate and the front substrate using the conductive member of the present invention, the charge to be charged to the spacer is absorbed on the substrate side, and high quality image display is achieved. A possible image display device can be provided.

  In addition, the silica film is deposited on the entire surface of the spacer body to form a fine uneven surface, and the surface is roughened to adhere and conduct the conductive metal film formed on the outermost surface. Therefore, it is possible to prevent secondary electrons from being emitted due to charging by electron emission from the electron source.

  The conductive film to be deposited on the surface of the spacer can be formed by, for example, depositing the spacer body in a solution in which ATO or PTO and an inorganic binder are mixed by dipping, followed by baking. . The spacer SPC configured in this manner is bonded and fixed to the scanning line and the anode by the above-described conductive member FGS, so that the charge-up portion charged in the spacer SPC can be easily discharged and the influence on the electron flow can be prevented. The

  In the above-described embodiment, the structure using the MIM type as the electron source has been described as an example. However, the present invention is not limited to this, and the self-luminous image display using the various electron sources described above. Needless to say, it can be applied to the apparatus.

It is a figure explaining an example of the image display apparatus by this invention. It is a schematic diagram explaining the detailed structure of the cross section along the A-A 'line of FIG. It is a principal part expanded sectional view of FIG. 1 is a partially broken perspective view illustrating an example of the overall structure of an image display device according to the present invention more specifically. FIG. It is sectional drawing cut | disconnected along the A-A 'line | wire of FIG. It is a schematic diagram explaining the structural example of 1 pixel of the image display apparatus of this invention. It is a figure explaining the example of an equivalent circuit of the image display apparatus of this invention.

Explanation of symbols

PNL1 ... Back panel, PNL2 ... Front panel, SUB1 ... Back substrate, SUB2 ... Front substrate, CL ... Signal line, CLT ... Signal line lead terminal, GL ... Scanning line , GLT ... scanning line lead terminal, SPC ... spacer, PH ... phosphor layer, BM ... black matrix, AD ... anode, MFL ... frame glass, FGS ... conductive member , FGM ... sealing member.

Claims (6)

  A conductive member composed of a phosphate-based glass containing a transition metal element and silver or copper metal particles, wherein there are two or more valences of at least one of the transition metal elements Conductive member. A conductive member containing phosphate glass containing at least one element of vanadium, niobium, tungsten, molybdenum, and iron, and silver or copper metal particles, wherein the one arbitrary element has two kinds of valences Conductive member composed of elements. A conductive member composed of glass containing at least 55 to 75 wt% V ₂ O ₅ , 15 to 30 wt% P ₂ O ₅ , and ₅ to 25 wt% BaO, and silver or copper metal particles by weight percentage. A conductive member composed of glass containing at least ₅ to 50 wt% WO ₃ , 20 to 40 wt% P ₂ O ₅ , and ₅ to 25 wt% BaO by weight percentage, and silver or copper metal particles.   The conductive member according to any one of claims 1 to 4, wherein a mixing ratio of silver or copper metal particles is 10% by volume or more and 50% by volume or less. A number of signal lines extending in a first direction and arranged in parallel in a second direction intersecting the first direction, and the signal lines are insulated from each other and extend in the second direction to A rear substrate on which a display region is formed that includes a large number of scanning lines arranged in parallel in the first direction and a large number of pixels having electron sources provided in the vicinity of intersections of the signal lines and the scanning lines. A back panel consisting of
A front panel comprising a front substrate on which a plurality of color phosphor layers and an anode that emit light by excitation of electrons extracted from the electron source in the display area of the rear panel are formed;
A plurality of spacers that are joined by a conductive member between the back panel and the front panel in the display area and hold the two panels at a predetermined interval;
An image display device comprising a frame glass hermetically sealed by interposing a sealing member around the back panel and the front panel;
An image display device, wherein the conductive member is composed of a phosphate glass containing a transition metal element and the same element having a different valence, and silver or copper metal particles.

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