JPH09293470A - Fluorescent character display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb a difference in coefficient of thermal expansion between a single crystal substrate and a vacuum container. SOLUTION: A conductive support 8 is arranged between a cathode substrate 5 comprising a single crystal substrate and an anode substrate 1, and wiring is performed between both substrates. An insulating support 6 is arranged between the cathode substrate 5 and a back plate 4. The cathode substrate 5 is interposed between the insulating support 6 and the conductive support 8, and fixed between the back plate 4 and the anode substrate 1. A gap is formed between the edge part of the cathode substrate 5 and a seal part 3. The expansion and contraction of the cathode substrate 5 to the anode substrate 1 and the back plate 4 can be absorbed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent display device in which a substrate having a flat cathode is housed in a vacuum container.

[0002]

2. Description of the Related Art An electric field applied to a metal or semiconductor surface is 10
^{At a} voltage of about ⁹ [V / m], the tunnel effect allows electrons to pass through the barrier, so that electrons are emitted in a vacuum even at room temperature. This is called field emission, and a cathode that emits electrons based on this principle is called a field emission cathode (hereinafter referred to as FEC).

In recent years, it has become possible to produce a micron-sized FEC by making full use of semiconductor integration technology. As one example, an FEC called a Spindt type is known. This FEC is manufactured in a planar shape by using semiconductor microfabrication technology, and the distance between the cone-shaped emitter, that is, the emitter cone and the gate electrode can be set to submicron.
It becomes possible to emit electrons from the emitter cone by applying a voltage of volt. Since the pitch between the emitter cones can be made to be 5 to 10 microns, tens to hundreds of thousands of FECs can be provided on one substrate. As described above, it is possible to manufacture a planar FEC, and it has been proposed to apply the FEC as a field emission electron source for a fluorescent display device, a CRT, an electron microscope, or an electron beam device.

Such an FEC can also be provided on a silicon substrate, and a conventional fluorescent display device disclosed in Japanese Patent Laid-Open No. 6-111735, in which the FEC is formed on the silicon substrate in FIG. A configuration example is shown. In FIG. 4, the silicon substrate 101 is placed and fixed on the back plate 116. An insulating layer 106 is formed on the surface of the silicon substrate 101, and a gate electrode 105 is formed on the insulating layer 106. Then, a cone-shaped emitter cone 107 for field emission of electrons is formed in an opening provided so as to penetrate the gate electrode 105 and the insulating layer 106. further,
A conductor pattern 108 and the like are formed on the silicon substrate 101, and conductive bumps 109 and bumps 110 are formed on the conductor pattern 108.

Further, an anode substrate 111 is arranged to face the back plate 116 with a small space therebetween, and an anode electrode 113, an anode wiring 118 and a wiring conductor 112 are formed on the anode substrate 111. A fluorescent substance 114 is deposited on the anode electrode 113, and the fluorescent substance 114 is irradiated with electrons emitted from the emitter cone 107 to emit light. Then, the anode wiring 118 and the wiring conductor 118
The bump 109 and the bump 110 are electrically connected to the conductive pattern 10 on which the silicon substrate 101 is formed.
8 is connected. Furthermore, the back plate 116 and the anode substrate 111 are sealed by a seal 117, and the inside of the container formed by the back plate 116, the anode substrate 111, and the seal 117 is evacuated.

In the thus constructed fluorescent display device, the FEC formed on the silicon substrate 101 is
A drive voltage or a signal is applied through the wiring conductor 112 drawn from the anode substrate 111 to bring it into an operating state.
That is, through the bumps 109 and 110, the FEC
Will be driven. The display pattern of the phosphor 114 emitted by the field-emitted electrons by the operation of the FEC on the silicon substrate 101 is observed through the anode substrate 111.

Further, the FEC formed on the silicon substrate described in Japanese Patent Laid-Open No. 6-295689 in FIG.
Another structural example of a conventional fluorescent display device using is shown. A cathode substrate 201 made of a silicon substrate on which a planar cathode is formed is attached to a lead frame 205 by a supporting member 203. The cathode substrate 201 attached to the lead frame 205 is a box-shaped container unit 2
It is stored in 20. On the other hand, the anode substrate 211 is provided with an anode conductor 214 and a phosphor layer 215 formed on the anode conductor 214. The anode substrate 211 is attached to the holding frame 217. Then, the anode substrate 211 is aligned with the cathode substrate 201, and the mounting flange 21 of the holding frame 217 is attached.
9 and the part of the lead frame 205 that abuts on this are fixed.

When placed in a heating furnace in this state, the sealing material 221 provided on the periphery of the anode substrate 211 and the cathode substrate 201 is melted, and the anode substrate 211 and the cathode substrate 201 are sealed. . As a result, an envelope containing the anode substrate 211 and the cathode substrate 201 is completed, and then the inside of the envelope is evacuated and sealed to manufacture a fluorescent display device. Note that reference numeral 213 denotes a getter, which is flashed by being subjected to high-frequency induction heating after the sealing to form a getter mirror in the container part 220. By this getter mirror, the gas remaining in the envelope is adsorbed and the inside of the envelope can be maintained in vacuum.

Further, the lead frame 205 is drawn out from the envelope to form a terminal, and by applying a driving voltage, an image signal or the like to this terminal, the FEC formed on the cathode substrate 201 is removed. A desired display pattern can be displayed on the anode substrate 211 by emitting electrons. The cathode substrate 201 and the terminals of the lead frame 205 are electrically connected by bumps 210.

[0010]

However, in the fluorescent display device shown in FIG. 4, bumps are formed on a silicon substrate on which a planar cathode is formed, and the bumps are used to connect to an anode substrate. The wiring conductor on the anode substrate is pulled out. Therefore, there is a problem that the gap between the anode substrate and the silicon substrate can be formed only to about 100 μm or less. Further, when the bumps are formed by plating, a chemical treatment must be performed on the completed silicon substrate or anode substrate on which the cathode is formed, which causes a problem that the yield is deteriorated. Furthermore, if bumps are formed using wire bonding,
Since it takes time to form the bumps, there is a problem that the number of products to be produced is limited.

Furthermore, in the fluorescent display device shown in FIG. 5, since the cathode substrate made of a silicon substrate is sandwiched between the lead frames, it is possible when the substrate is small, but when it is a large substrate. Has the following problems. 1. Since the lead frame has to be enlarged according to the size of the substrate, the cost is high. 2. It is difficult to make the lead frame because the pad precision for connection is required. 3. Since the gap between the anode substrate and the cathode substrate is secured by the peripheral lead frame, the gap may change between the central portion and the peripheral portion in a large substrate.

Furthermore, the silicon substrate has a different coefficient of thermal expansion from glass generally known as a container material for a fluorescent display tube, and when the silicon substrate is mounted on the glass substrate,
There is a problem that the silicon substrate or the glass substrate may be damaged due to the difference in thermal expansion coefficient. This problem occurs similarly when the silicon substrate is sandwiched between the lead frames, although it is somewhat improved.

Furthermore, in the fluorescent display device shown in FIG. 4, if an active circuit is formed under the pad on which the bump is formed, the active circuit may be damaged when the bump is formed by wire bonding. When forming bumps by plating, a barrier metal is required on the pad, which increases the number of manufacturing processes by one step. Furthermore, when performing multi-layer wiring on the anode substrate or the cathode substrate, it is necessary to form an insulating layer or the like, which causes problems such as an increase in the number of manufacturing steps, insulation failure, and breakdown voltage.

Therefore, it is an object of the present invention to provide a fluorescent display device which can eliminate the need for bumps and lead frames and can solve the problems caused by the difference in thermal expansion coefficient.

[0015]

In order to achieve the above object, a fluorescent display device of the present invention comprises a substrate on which at least a planar cathode is formed, a back plate for accommodating the substrate, and a light emitting portion. A vacuum container composed of a transparent anode substrate, a first insulating pillar disposed between the one surface of the substrate and the back plate, and a first insulating pillar disposed between the other surface of the substrate and the one surface of the anode substrate. A first wiring pattern formed on the other surface of the substrate, and a second wiring pattern formed on one surface of the anode substrate. Is electrically connected, and the substrate is sandwiched and fixed between the back plate and the anode substrate by the first insulating pillar and the conductive pillar and the second insulating pillar. hand That.

Further, in the above-described fluorescent display device of the present invention, a gap is provided between a seal portion that seals between the back plate and the anode substrate and an edge of the substrate, and the anode substrate and the back substrate are provided. The difference in thermal expansion coefficient between the plate and the substrate is absorbed. further,
In the above-described fluorescent display device of the present invention, a getter is incorporated in the space between the back plate and the substrate formed by the insulating pillar.

According to the present invention as described above, since the conductive columns support the conduction between the anode substrate and the cathode substrate, it is possible to eliminate all the defects of the bumps and the lead frame. Therefore, it is possible to sufficiently deal with a large substrate. Further, all the wirings for energizing the cathode substrate can also be drawn out from the anode substrate. Further, since the cathode substrate, which is a silicon substrate, for example, is sandwiched and fixed in the vacuum container by the conductive support, the second insulating support, and the first insulating support,
The cathode substrate can expand and contract with respect to the vacuum container. Therefore, it is possible to absorb the difference in the coefficient of thermal expansion, prevent damage to the container, and prevent cracking of the cathode substrate.

[0018]

FIG. 1 shows the configuration of an embodiment of the fluorescent display device of the present invention. In FIG. 1, 1 is an anode substrate made of transparent glass, 2 is an external extraction electrode formed on one surface of the anode substrate 1, 3 is a sealing portion made of frit glass or the like forming the side surface of a vacuum container, and 4 is glass. The anode plate 1, the seal portion 3, and the back plate 4 form a vacuum container. Further, 5 is a cathode substrate made of, for example, a single crystal silicon substrate, 6 is an insulating support column arranged between the cathode substrate 5 and the back plate 4, and 7 is an FEC array 1.
0 is a driver for driving, 8 is a conductive pillar arranged between the cathode substrate 5 and the anode substrate 1, and 9 is an anode wiring to which a phosphor is adhered, and 9 (G), 9 (R),
Reference numeral 9 (B) is an anode wiring to which phosphors that emit green, red, and blue are respectively deposited.

Further, 10 is an FEC array formed on the cathode substrate 5, and its structure is composed of a large number of Spindt-type FECs as shown in FIG. Reference numeral 11 is a multi-layer wiring formed on the cathode substrate 5 for connecting the anodes 9, 12 is a cathode wiring formed on the cathode substrate 5, and 13 is a wiring pattern formed on the anode substrate 1. The FEC array 10 and the cathode wiring 12 are formed on the cathode substrate 5 as an active matrix, and a large number of conductive columns 8 are planted in a predetermined pad portion on the active surface of the cathode substrate 5.
A large number of insulating struts 6 are planted on the other surface. Although not shown, a large number of insulating columns for maintaining a constant gap between the cathode substrate 5 and the anode substrate 1 are provided between the cathode substrate 5 and the anode substrate 1 as well as the conductive columns 8. Has been done.

The cathode substrate 5 on which the conductive columns 8 and the insulating columns 6 are implanted is incorporated in a glass container constituted by the back plate 4 and the seal portion 3. Further, while aligning with the cathode substrate 5, the anode substrate 1 is opposed to the cathode substrate 5 and sealed. At this time, the other end of the conductive support 8 is connected to a predetermined pad formed on the anode substrate 1. As a result, a fluorescent display tube as shown in FIG. 1 is manufactured.

Next, a method for implanting the insulating support pillars 6 and the conductive support pillars 8 on the cathode substrate 5 will be briefly described. The insulating support 8 is made by filling a support into a jig in which an insulating support is planted at a predetermined position on the cathode substrate 5, and applying an adhesive to the surface of the support on the cathode substrate 5 side.
Next, the insulating support pillars 6 are planted on the cathode substrate 5 by aligning with the cathode substrate 5 and adhering it on the cathode substrate 5. In addition, the conductive support pillars 8 are prepared by filling the support pillars into a jig processed so that the conductive support pillars can be implanted at predetermined positions on the cathode substrate 5, and the conductive paste is applied to the surface of the support pillars on the cathode substrate 5 side. Apply. Next, the jig is turned upside down while performing air suction on the jig, and the cathode substrate 5
The pillars are transferred onto the cathode substrate 5 in alignment with. In this way, the conductive columns 8 are planted on the cathode substrate 5.

Glass, ceramics, etc. can be used as the material of the insulating support column 6, and the support column height is about 1.
mm or less. In addition, as the material of the conductive support 8,
Conductive material (A
g, Au, Ni, Cu, etc.) can be used, and the height of the column is about 20.
0 μm. The conductive support 8 may be made of metal. Furthermore, as the adhesive applied to the insulating support column 6, a glass paste or the like that emits less gas in the tube and does not carbonize during firing is used. As the conductive paste applied to the conductive columns 8, a paste obtained by dispersing a conductive filler in a glass paste is used. Any material may be used as the filler material as long as it has conductivity and can be dispersed in the paste.

By the way, as the wiring pattern formed on the anode substrate 1, anode wirings 9 (G), 9 (R), 9 (B) coated with a phosphor and the conductive support 8 are provided on the cathode side. The external extraction electrode 2 is connected to the external extraction electrode 2 and the end of the external extraction electrode 2 is extracted from the inside of the vacuum container.
This state is shown in the perspective view of FIG.
One surface of the conductive columns 8-1, 8-2, and 8-3 is electrically connected to and planted at the ends of the two, 12-2, and 12-3, respectively. 1,8-2,8-
The other surface of 3 is electrically connected to the external extraction electrodes 2-1, 2-2, 2-3 formed on the anode substrate 1.
In this case, the conductive columns 8-1, 8-2, 8-3 are inside the vacuum container, and the external extraction electrodes 2-1, 2-2, 2-3 are drawn out from the inside of the vacuum container. Note that the cathode wiring also includes wiring to the gate electrode. Further, the external extraction electrodes are not limited to the three shown in the figure,
The number of gate electrodes formed on the cathode substrate 5 and the number required to supply to the cathode electrodes, and the anode substrate 1
It is provided as many as necessary to supply to the side.

As described above, the drive voltage signal and the display signal supplied to the cathode substrate 5 side are supplied to the external extraction electrodes 2-1 and 2-1.
, −2, 2-3, and so on to be supplied from the anode substrate 1 side to the cathode substrate 5 via the conductive columns 8-1, 8-2, 8-3. Therefore, all the wiring of the fluorescent display tube is extracted by the external extraction electrodes 2-1, 2-2, 2-3 ... Formed on the anode substrate 1, so that the bare chip of the driver is directly connected to the anode substrate 1. COG (Chip On Glass) method, FP
It becomes possible to employ a connecting means such as connecting C and TAB with an anisotropic sheet.

Further, the insulating pillar 6 can secure a sufficient space between the cathode substrate 5 and the back plate 4 for disposing the getter 7. In addition, the insulating support 6
A circuit such as the driver 7 for driving the FEC array 10 may be provided in the space formed by. In addition, the conductive columns 8 are the cathode substrate 5 and the anode substrate 1.
Since it can be arranged at any position, the degree of freedom in designing the wiring of the cathode substrate 5 is increased and the cathode substrate 5 can be made smaller.

Next, the multilayer wiring 11 formed on the cathode substrate 5 will be described with reference to FIG. Anode wiring (G), 9 formed on the anode substrate 1
When sequentially switching (R) and 9 (B), it is necessary to cross a part of the anode wiring 9 to perform multilayer wiring. In this cloth, an insulating layer and a conductive layer must be formed on the insulating layer, which increases the number of processing processes and causes problems of the insulating property and the pressure resistance. Therefore, as shown in FIG. 3, for example, the conductive posts 8 are provided on the two anode wirings 9 (G).
And the other ends of the two conductive columns 8 are connected to both ends of the multilayer wiring 11 formed on the cathode substrate 5. As a result, wiring can be performed in the same state as when the anode wiring 9 (G) is crossed. According to this method, problems of insulation and pressure resistance do not occur.

Next, a means for absorbing the difference in thermal expansion coefficient between the cathode substrate 5 made of a single crystal silicon substrate and the back plate 4 and the anode substrate 1 will be described.
A gap is formed between the cathode substrate 5 and the seal portion 3 forming the vacuum container as shown in FIG. 1, and the cathode substrate 5 is arranged between the back plate 4 and the cathode substrate 5. The back plate 4 and the anode substrate 1 are provided by the installed insulating columns 6, the conductive columns 9 and the insulating columns arranged between the anode substrate 1 and the cathode substrate 5.
Even if the temperature of the cathode substrate 5 changes relative to the vacuum container due to the temperature difference between the cathode substrate 5 and the vacuum substrate, the edge of the cathode substrate 5 abuts the seal portion 3 and the seal portion 3 or the cathode. There is no risk of damaging the substrate 5.

Since the insulating column 6 is not fixed to the back plate 4 with an adhesive, the cathode substrate 5
It can be moved according to the expansion and contraction of. However, since the amount of expansion and contraction of the cathode substrate 5 is small and the amount of movement of the insulating support column 5 is also small, there is no other adverse effect. Further, one end of the conductive support column 8 is fixed on the pad of the cathode substrate 5, and the other end of the conductive support column 8 is fixed or temporarily fixed on the pad of the anode substrate 1. When the other end of the conductive support pillar 8 is fixed on the pad of the anode substrate 1, the conductive support pillar 8 is slightly bent in accordance with the expansion and contraction of the cathode substrate 5, and absorbs this. Therefore, no connection failure will occur even if the temperature changes.

Since the insulating support column 6 does not affect the display unlike the conductive support column 8, the diameter of the support column can be increased, and therefore the height can be adjusted arbitrarily. Further, since the space formed by the insulating support column 6 can be provided between the cathode substrate 5 and the back plate 4,
The capacity in the vacuum container can be increased, and the exhaust conductance during exhaust can be improved. In the above description, the cathode substrate 5 is described as a silicon single crystal substrate, but the cathode substrate 5 in the present invention is not limited to this, and any material can be used as long as it can be used as the cathode substrate. Can be used.

[0030]

As described above, according to the present invention, since the conductive substrate supports the conduction between the anode substrate and the cathode substrate, all the defects of the bumps and the lead frame can be eliminated. Therefore, it is possible to sufficiently cope with a large substrate. Further, all the wirings for energizing the cathode substrate can also be drawn out from the anode substrate. Further, since the cathode substrate, which is a single crystal silicon substrate, for example, is sandwiched and fixed in the vacuum container by the conductive columns and the insulating columns, the cathode substrate can expand and contract with respect to the vacuum container. Therefore, it is possible to absorb the difference in the coefficient of thermal expansion, prevent damage to the container, and prevent cracking of the cathode substrate.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a fluorescent display device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship among external extraction electrodes, cathode wirings, and conductive posts in the fluorescent display device according to the embodiment of the present invention.

FIG. 3 is a diagram showing the relationship between the anode wiring, the multilayer wiring, and the conductive support in the fluorescent display device according to the embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a conventional fluorescent display device including a Spindt-type field emission cathode.

FIG. 5 is a diagram showing a structure of a conventional fluorescent display device including a field emission cathode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode substrate 2 External extraction electrode 3 Seal part 4 Back plate 5 Cathode substrate 6 Insulating column 7 Getter 8 Conductive column 9 Anode wiring 10 FEC array 11 Multilayer wiring 12 Cathode wiring 13 Wiring pattern

Claims (3)

[Claims] 1. A vacuum container comprising a substrate on which at least a planar cathode is formed, a back plate accommodating the substrate, a transparent anode substrate on which a light emitting portion is formed, one surface of the substrate and the back plate. A first insulating pillar disposed between the first surface and the second surface of the anode substrate and the second surface of the anode substrate. The first wiring pattern formed on the other surface of the substrate is electrically connected to the second wiring pattern formed on the one surface of the anode substrate, and the substrate is the first insulating pillar. And a conductive pillar and a second insulating pillar that are sandwiched and fixed between the back plate and the anode substrate. 2. A thermal expansion between the anode substrate and the back plate, and the substrate is provided by providing a gap between a seal portion that seals between the back plate and the anode substrate and an edge of the substrate. A fluorescent display device characterized by absorbing a difference in coefficient. 3. A fluorescent display device, characterized in that a getter is incorporated in a space between the back plate and the substrate formed by the insulating support.