Plane display device

Abstract

An embodiment of the invention provides a plane display device in which a cathode panel having a plurality of electron emitting areas provided therein, and an anode panel having phosphor layers and an anode electrode provided therein are joined to each other in their peripheral portions, and a space defined between the cathode panel and the anode panel is kept at a vacuum, the plane display device, including: an exhaust tube made of a conductive material, the exhaust tube having one end portion communicating with the space, and the other end portion located outside the plane display device; and an elastic member made of a conductive material; in which the exhaust tube and the anode electrode are electrically connected to each other through the elastic member disposed in the space; and a predetermined voltage is applied to the anode electrode through the exhaust tube and the elastic member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual partial end view of a plane display device according to Embodiment 1 of the present invention;

FIG. 2 is a schematic exploded perspective view when a cathode panel, an anode panel, a getter box and the like are exploded;

FIG. 3 is a schematic plan view explaining an arrangement state of partition walls, spacers, and phosphor layers in the plane display device according to Embodiment 1 of the present invention;

FIG. 4 is a schematic constructional view of a connection portion between an anode electrode controlling circuit and an exhaust tube;

FIGS. 5A and 5B are respectively conceptual partial end views of a change and another change of Embodiment 1 which are different in construction of an elastic member from each other;

FIGS. 6A and 6B are respectively conceptual partial end views of still another change and yet another change of Embodiment 1 which are different in construction of an elastic member from each other;

FIG. 7 is a conceptual partial end view of a plane display device according to Embodiment 2 of the present invention;

FIG. 8 is a conceptual partial end view of a plane display device having spindt field emission elements incorporated therein in the related art; and

FIG. 9 is a partial schematic exploded perspective view of a cathode panel and an anode panel when the cathode panel and the anode panel are exploded.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described in detail hereinafter with reference to the accompanying drawings.

Embodiment 1

FIG. 1 is a conceptual partial end view of a plane display device according to Embodiment 1 of the present invention. A plane display device according to Embodiment 1 or Embodiment 2 which will be described later of the present invention is a cold cathode field electron emission display device (hereinafter referred to as “a display device” for short) similarly to the plane display device which was described in the paragraph of BACKGROUND OF THE INVENTION. Here, a schematic partial exploded perspective view of a cathode panel CP and an anode panel AP when the cathode panel CP and the anode panel AP in the display device according to Embodiment 1 or Embodiment 2 which will be described later of the present invention are exploded is similar to that shown in FIG. 9.

The display device according to Embodiment 1 or Embodiment 2 which will be described later of the present invention is one in which the cathode panel CP, and the anode panel AP are joined to each other in their peripheral portions, and a space defined between the cathode panel CP and the anode panel AP is kept at a vacuum. Here, the cathode panel CP has a plurality of electron emitting areas EA provided therein. Also, the anode panel AP has phosphor layers 22 and an anode electrode 24 provided therein.

Also, the display device of Embodiment 1 includes:

(A) an exhaust tube 150 which is made of a conductive material (more specifically, a nickel alloy in Embodiment 1), one end portion of which communicates with the space, and the other end portion of which is located outside the display device; and

(B) an elastic member 151 made of a conductive material (more specifically, a stainless steel in Embodiment 1).

Here, in Embodiment 1, the exhaust tube 150 and the anode electrode 24 are electrically connected to each other through the elastic member 151 disposed within the space. A predetermined voltage (an anode voltage V_A) is applied to the anode electrode 24 through the exhaust tube 150 and the elastic member 151.

FIG. 2 shows a schematic exploded perspective view when the cathode panel CP, the anode panel AP, a getter box 160 and the like are exploded. In the display device of Embodiment 1, the getter box 160 which communicates with the space is mounted to the cathode panel CP. More specifically, one or plural through holes (one though hole in FIG. 2) 161 are formed in the cathode panel CP. The getter box 160 made of a ceramic material is bonded to a supporting body 10 by using a frit glass (not shown) so as to close up the through hole 161 from the outside of the cathode panel CP. Also, the exhaust tube 150 is mounted to the getter box 160 by using a frit glass 152. The exhaust tube 150 is disposed so that one end portion thereof protrudes from a bottom portion of the getter box 160 to the anode panel side. Thus, the exhaust tube 150 communicates with the space defined between the cathode panel CP and the anode panel AP. On the other hand, the other end portion of the exhaust tube 150 is located outside the display device, is bonded to the getter box 160 by the application of a pressure, and is sealed. Note that, a getter (not shown) is accommodated in the getter box 160.

More specifically, as shown in FIGS. 1 and 2, the elastic member 151 includes an approximately circular engagement portion 151A, an arcuate portion 151B, and a connection portion 151C through which the approximately circular engagement portion 151A and the arcuate portion 151B are connected to each other. Also, one end of the elastic member 151 abuts against the anode electrode 24, and the other end thereof is fixedly fastened to the exhaust tube 150. More specifically, a portion, of the exhaust tube 150, which protrudes from a bottom portion of the getter box 160 is inserted into the approximately circular engagement portion 151A. In addition, the arcuate portion 151B constituting the elastic member 151 is disposed so as to abut against (is pressed to) the anode electrode 24. As a result, the exhaust tube 150 and the anode electrode 24 are electrically and reliably connected to each other through the elastic member 151.

As shown in FIG. 1, an anode electrode controlling circuit 33 applies a predetermined voltage to the anode electrode 24 through the exhaust tube 150 and the elastic member 151. FIG. 4 shows a schematic constructional view of a connection portion 70 between the anode electrode controlling circuit 33 and the exhaust tube 150. The connection portion 70 includes a cable 71 consisting of a covering 71A and a core wire 71B, a clip 72 made of a metal and connected to the core wire 71B and an insulating portion 73 which surrounds an outer circumference of the clip 72. According to this construction, the portion to which the anode voltage is applied is prevented from being exposed to the outside in a state in which the connection portion 70 is mounted to the exhaust tube 150.

As shown in FIG. 1, in the cathode panel CP of the display device of Embodiment 1, each of the cathode electrodes 11 has a strip-like shape extending in a first direction (in a Y direction), and each of the gate electrodes 13 also has a strip-like shape extending in a second direction (in an X direction) different from the first direction. Each of the cathode electrodes 11 and each of the gate electrodes 13 are formed in strip shapes, respectively, in directions along which their projected images intersect perpendicularly each other. Overlap areas in which the strip-like cathode electrodes 11 and the strip-like gate electrodes 13 overlap each other are electron emitting areas EA, respectively. A plurality of field emission elements are provided in one electron emitting area EA corresponding to one sub-pixel. Also, the electron emitting areas EA each corresponding to one sub-pixel are arranged in two-dimensional matrix within an effective area of the cathode panel CP.

An interlayer insulating layer 16 is formed on an insulating layer 12 and each of converging electrodes 17 is provided on the interlayer insulating layer 16. The converging electrodes can exert a common converging effect on a plurality of field emission elements. A third opening portion 14C communicating with a first opening portion 14A is formed in the interlayer insulating layer 16.

In Embodiment 1, the field emission element constituting the electron emitting area EA is constituted by a spindt field emission element. Here, the spindt field emission element includes:

(a) the cathode electrodes 11 formed on the supporting body 10;

(b) the insulating layer 12 formed on the supporting body 10 and each of the cathode electrodes 11;

(c) the gate electrodes 13 each of which is formed on the insulating layer 12;

(d) the opening portion (14) formed in each of the gate electrodes 13 and the insulating layer 12 (including the first opening portion 14A formed in each of the gate electrodes 13, and the second opening portion 14B formed in the insulating layer 12); and

(e) the conical electron emitting portion 15 formed on the cathode electrode 11 located in the bottom portion of the opening portion 14.

In Embodiment 1, the anode panel AP includes the substrate 20, the phosphor layers 22 formed on the substrate 20, and the anode electrode 24 covering the phosphor layers 22. More specifically, the anode panel AP includes the substrate 20, the phosphor layers 22 (red emission phosphor layers 22R, green emission phosphor layers 22G, and blue emission phosphor layers 22B), and the anode electrode 24 formed over the phosphor layer 22. Here, the phosphor layers 22 are made from a large number of phosphor particles, and are formed between the partition walls 21 formed on the substrate 20. The anode electrode 24 has one sheet-like shape so as to cover the effective area, and is formed so as to cover the partition walls 21 and the phosphor layers 22. A light absorbing layer (black matrix) 23 is formed between the adjacent phosphor layers 22 and also between each of the partition walls 21 and the substrate 20 in order to prevent the color turbidity and the optical crosstalk of a displayed image from being generated. Also, a space defined between the cathode panel CP and the anode panel AP is kept at a vacuum (for example, having a pressure of 10⁻³ Pa or less).

FIG. 3 is a schematic plan view explaining the arrangement state of the partition walls 21, the spacers 40 and the phosphor layers 22 in the display device of Embodiment 1. An illustration of the anode electrode 24 is emitted here for the sake of simplicity in FIG. 3. The planar shape of the partition walls 21 is a lattice shape (rub shape), that is, is a shape surrounding all sides of each of the phosphor layers 22, for example, having approximately a rectangle as a planar shape, and corresponding to one sub-pixel. A part of the partition walls 21 functions as a spacer holding portion 25 as well for holding the spacers 40.

One sub-pixel includes the electron emitting area EA on the cathode panel side, and the phosphor layer 22, on the anode panel side, facing a group of field emission elements. The pixels, for example, are arranged on the order of several hundreds of thousands to several millions in the effective area. Note that, in the color display device, one pixel includes a set of red emission sub-pixel, green emission sub-pixel, and blue emission sub-pixel.

In Embodiment 1, the cathode electrode 11 is connected to a cathode electrode controlling circuit 31. Each of the gate electrodes 13 is connected to a gate electrode controlling circuit 32. Also, each of the converging electrodes 7 is connected to a converging electrode controlling circuit (not shown). As described above, the anode electrode 24 is connected to the anode electrode controlling circuit 33 through the elastic member 151 and the exhaust tube 150. These controlling circuits can be structured in the form of the well known circuits, respectively. In the phase of the actual operation of the display device, an anode voltage V_A which is applied from the anode electrode controlling circuit 33 to the anode electrode 24 is normally constant. For example, the anode voltage V_A can be set in the range of 5 to 15 kV, more specifically, for example, can be set to 9 kV (for example, d₀=2.0 mm in this case). On the other hand, in the phase of the actual operation of the display device, any of the following methods may be adopted for a voltage V_C applied to each of the cathode electrodes 11, and a voltage V_G applied to each of the gate electrodes 13:

(1) a method in which the voltage V_C applied to each of the cathode electrodes 11 is made constant, and the voltage V_G applied to each of the gate electrodes 13 is made variable;

(2) a method in which the voltage V_C applied to each of the cathode electrodes 11 is made variable, and the voltage V_G applied to each of the gate electrodes 13 is made constant; and

(3) a method in which the voltage V_C applied to each of the cathode electrodes 11 is made variable, and the voltage V_G applied to each of the gate electrodes 13 is also made variable.

In the phase of the actual operation of the display device, the cathode electrode controlling circuit 31 applies the relatively negative voltage (V_C) to each of the cathode electrodes 11. The gate voltage controlling circuit 32 applies the relatively positive voltage (V_G) to each of the gate electrodes 13. The converging electrode controlling circuit, for example, applies 0 V to each of the converging electrodes 17. Also, the anode electrode controlling circuit 33 applies the higher positive voltage (the anode voltage V_A) than that applied to each of the gate electrodes to the anode electrode 11. When an image is intended to be displayed on such a display device, for example, the cathode electrode controlling circuit 31 inputs a scanning signal to each of the cathode electrodes 11, and the gate electrode controlling circuit 32 inputs a video signal corresponding to the image to each of the gate electrodes 13. It should be noted that the cathode electrode controlling circuit 31 may input a video signal to each of the cathode electrodes 11, and the gate electrode controlling circuit 32 may input a scanning signal to each of the gate electrodes 13. The electrons are emitted from the electron emitting portion 15 in accordance with the quantum tunneling effect caused by the electric field which is generated when a suitable voltage is applied across the corresponding ones of the cathode electrodes 11 and the corresponding ones of the gate electrodes 13. The anode electrode 24 attracts these electrons. Then, these electrons penetrate through the anode electrode 24 to collide with the corresponding ones of the phosphor layers 22. As a result, the corresponding ones of the phosphor layers 22 are excited to emit lights, respectively, thereby enabling a desired image to be obtained on a screen of the display device. In other words, the operation of the display device is basically controlled in accordance with the gate voltage V_G applied to each of the gate electrodes 13, and the cathode voltage V_C applied to each of the cathode electrodes 11.

A detailed description will be given hereinafter with respect to a method of manufacturing the display device according to Embodiment 1 of the present invention.

[Process-100]

Firstly, the getter box 160, the cathode panel CP, and the anode panel AP are prepared. In addition, the spacers 40 are also prepared. Here, the exhaust tube 150 and the elastic member 151 are mounted in a predetermined state to the getter box 160. A plurality of field emission elements each constituting the electron emitting area for emitting the electrons are formed on the supporting body 10 in the cathode panel CP. Also, the phosphor layers 22 with which the electrons emitted from the electron emitting areas collide, respectively, and the anode electrode 24 are formed on the substrate 20 in the anode panel AP.

[Process-110]

The getter box 160 is bonded to the supporting body 10 constituting the cathode panel CP by using a frit glass or the like.

[Process-120]

Also, the display device is assembled. More specifically, the spacers 40 are mounted to the spacer holding portion 25 of the anode panel AP, and the joining member 26 is disposed in a non-effective area of the anode panel AP. Then, the anode panel AP and the cathode panel CP are assembled so that the phosphor layers 22 and the electron emitting areas ED face each other, respectively, and the arcuate portion 151B constituting the elastic member 151 abuts against (is pressed to) the anode electrode 24. Each of the top surface and the bottom surface of the joining member 26 is coated with the frit glass. Here, this frit glass was temporarily fired at 350° C. for 20 minutes.

[Process-130]

After that, the entire assembly body is brought in a firing furnace, and is then subjected to heating processing within the firing furnace, thereby formally firing the entire assembly body at a temperature of about 400° C. for about 30 minutes. A pressure of the ambient atmosphere in the phase of the firing may be either a normal pressure or a reduced pressure. In addition, a gas constituting the ambient atmosphere may be either air or an inactive gas containing therein a nitrogen gas or a gas belonging to a zero group in the periodic series (for example, an Ar gas).

[Process-140]

After that, the entire assembly body is carried out from the firing furnace. The space defined among the cathode panel CP, the anode panel AP, and the joining member 26 is exhausted through the exhaust tube 150. Then, at a time point when the pressure in the space reaches about 10⁻⁴ Pa, the exhaust tube 150 is bonded to the getter box 160 by the application of a pressure to be sealed. Note that, it is suitable that the entire display device is temporarily heated and the temperature thereof is then caused to drop before performing the sealing because the residual gas can be discharged to the space and can be removed to the outside of the space through the exhaust process. The space defined among the cathode panel CP, the anode panel AP, and the joining member 26 can be kept at the vacuum in the manner as described above. After that, wirings are connected to necessary external circuits, thereby completing the display device of Embodiment 1.

FIGS. 5A and 5B respectively show conceptual partial end views of a change and another change of the elastic member 151 of the display device shown in FIG. 1. FIGS. 6A and 6B respectively show conceptual partial end views of still another change and yet another change of the elastic member 151 of the display device shown in FIG. 1. Here, illustrations of the spacers 40, and the phosphor layers 22, the light absorbing layer 23, the partition walls 21, and the like constituting the anode panel AP are omitted in these figures for the sake of simplicity. In addition, illustrations of the insulating layer 12, the gate electrodes 13, and the like constituting the cathode panel CP are also omitted in these figures for the sake of simplicity.

In each of the changes shown in FIGS. 5A and 5B, and FIGS. 6A and 6B, respectively, the elastic member 151 is constituted by a coil spring made of a stainless steel. Also, in the change shown in FIG. 5A, the other end of the elastic member 151 is fixed so as to be engaged with the outer circumference of the exhaust tube 150. In addition, in the change shown in FIG. 5B, the other end of the elastic member 151 is fixed so as to be engaged with an inner wall of the exhaust tube 150. Moreover, in the change shown in FIG. 6A, a washer 153 including an annular-shaped protrusion portion is mounted to the end portion of the exhaust tube 150. The other end of the elastic member 151 is fixedly fastened to the washer 153. Here, in each of the changes described above, the elastic member 151 is disposed so that one end thereof abuts against (is pressed to) the anode electrode 24.

In the change shown in FIG. 6B, the elastic member 151 is constituted by a plate made of a stainless steel similarly to that in Embodiment 1. Also, the other end of the elastic member 151 is fixed so as to contact the anode electrode 24. In addition, one end portion of the elastic member 151 is disposed so as to abut against the inner wall of the exhaust tube 150. Note that, one end portion of the elastic member 151 may be disposed so as to abut against an outer wall of the exhaust tube 150.

Embodiment 2

FIG. 7 shows a conceptual partial end view of a display device according to Embodiment 2 of the present invention. The display device of Embodiment 2 has the same construction and constitution as those of the display device of Embodiment 1 except for the construction and constitution of an exhaust tube portion. Thus, a detailed description of the entire display device is omitted here for the sake of simplicity. Hereinafter, the construction and constitution of the exhaust tube portion will be concretely described with reference to FIG. 7.

An exhaust tube 250 in the display device of Embodiment 2 is made of a conductive material (more specifically, a nickel alloy). One end portion 250A of the exhaust tube 250 communicates with a space (which is defined between the cathode panel CP and the anode panel AP and is kept at a vacuum), and the other end portion thereof is located outside the display device. Also, the one end portion 250A of the exhaust tube 250 directly contacts (that is, abuts against or is pressed to) the anode electrode 24. More specifically, the one end portion 250A of the exhaust tube 250 is constituted by a protrusion piece which has an elasticity and which extends from an exhaust main body 251. In addition, the other end portion of the exhaust tube 250 (an end portion of the exhaust main body 251) is located outside the display device, is bonded to the getter box 160 by the application of a pressure, and is sealed. Also, the anode electrode controlling circuit 33 applies the predetermined voltage (the anode voltage V_A) to the anode electrode 24 through the exhaust tube 250. A connection portion between the anode electrode controlling circuit 33 and the exhaust tube 250 can have the same constitution and construction as those of the connection portion 70 of the display device of Embodiment 1. Note that, the exhaust tube 250 is mounted to the getter box 160 which communicates with the space similarly to the exhaust tube 150 of the display device of Embodiment 1. More specifically, the exhaust main body 251 is mounted to the getter box 160 by using a frit glass 252.

Although the present invention has been described so far based on the preferred embodiments, the present invention is not intended to be limited thereto. That is to say, the constitutions and constructions of the plane display devices, the cathode panels, the anode panels, the exhaust tubes, the elastic members, the cold cathode field electron emission display devices, and the cold cathode field electron emitting elements which have been described in Embodiments 1 and 2 are merely exemplified, and thus can be suitably changed. In addition, the methods of manufacturing the cathode panel, the anode panel, the exhaust tube, the elastic member, the cold cathode field electron emission display device, and the cold cathode field electron emitting element are also merely exemplified, and thus can be suitably changed. Moreover, the various materials used in manufacturing the cathode panel, the anode panel, the exhaust tube, and the elastic member are merely exemplified, and thus can be suitably changed. Although the display device has been described by mainly giving the color display device as the example, the display device can also perform single color display.

The form in which one electron emitting portion exclusively corresponds to one opening portion has been described for the field emission element. However, a form in which a plurality of electron emitting portions correspond to one opening portion, or a form in which a plurality of electron emitting portions correspond to a plurality of opening portions can also be adopted depending on the structures of the field emitting elements. Or, a form can also be adopted in which a plurality of first opening portions are formed in each of the gate electrodes, a second opening portion communicating with corresponding one or ones of the plurality of first opening portions is formed in the insulating layer, and one or plural electron emitting portions are provided.

The electron emitting source can be constituted from the element commonly known as the surface-conduction electron emitting element. In the surface-conduction electron emitting element, pairs of electrodes are formed in matrix on the supporting body, for example, made of a glass. Here, a pair of electrodes are made of a conductive material such as a tin oxide (SnO₂), a gold (Au), an indium oxide (In₂O₃)/a tin oxide (SnO₂), carbon, or a palladium oxide (PdO), and has a minute area. Also, the pairs of electrodes are arranged at predetermined gaps. A carbon thin film is formed on each of the electrodes. Also, a row-direction wiring is connected to one of a pair of electrodes, and a column-direction wiring is connected to the other of the pair of electrons. A suitable voltage is applied each of a pair of electrodes, which result in that an electric field is applied to the carbon thin films facing each other through the given gap, and the carbon thin films emit the electrons. Such electrons are made to collide with the phosphor layers formed on the anode panel, so that the phosphor layers are excited to emit lights, thereby enabling a desired image to be obtained. Or, the electron emitting source can be constituted by the metal/insulating film/metal type element.

It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. A plane display device in which a cathode panel having a plurality of electron emitting areas provided therein, and an anode panel having phosphor layers and an anode electrode provided therein are joined to each other in their peripheral portions, and a space defined between said cathode panel and said anode panel is kept at a vacuum, said plane display device, comprising: an exhaust tube made of a conductive material, said exhaust tube having one end portion communicating with said space, and the other end portion located outside said plane display device; andan elastic member made of a conductive material;wherein said exhaust tube and said anode electrode are electrically connected to each other through said elastic member disposed in said space; anda predetermined voltage is applied to said anode electrode through said exhaust tube and said elastic member.

2. The plane display device according to claim 1, wherein a getter box communicating with said space is mounted to said cathode panel and/or said anode panel; and said exhaust tube is mounted to said getter box.

3. The plane display device according to claim 1, wherein one end of said elastic member abuts against said anode electrode, and the other end of said elastic member is fixedly fastened to said exhaust tube.

4. A plane display device in which a cathode panel having a plurality of electron emitting areas provided therein, and an anode panel having phosphor layers and an anode electrode provided therein are joined to each other in their peripheral portions, and a space defined between said cathode panel and said anode panel is kept at a vacuum, said plane display device, comprising: an exhaust tube made of a conductive material, said exhaust tube having one end portion communicating with said space, and the other end portion located outside said plane display device;wherein one end portion of said exhaust tube directly contacts said anode electrode; anda predetermined voltage is applied to said anode electrode through said exhaust tube.

5. The plane display device according to claim 4, wherein a getter box communicating with said space is mounted to said cathode panel and/or said anode panel; and said exhaust tube is mounted to said getter box.