JPH0821350B2 - Fluorescent display tube - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fluorescent display tube, and more particularly, to a fluorescent display equipped with a driving IC chip for driving a display portion by a fluorescent body inside a vacuum container. The present invention relates to a tube, a so-called chip-in-glass type fluorescent display tube.

[Conventional technology]

Conventionally, this type of fluorescent display tube has been the driving IC on the substrate.
As shown in FIGS. 5 and 6, the chip arrangement structure is
Display unit 2 including display segments 2a to 2e having a predetermined pattern
And the glass substrate 1 on which the conductor wiring is formed is used as an anode substrate, and a driving IC chip 4 for driving the display unit 2, that is, a silicon chip 4 is die-bonded to a part of the glass substrate 1. Then, the bonding pad 5 as an electrode terminal on the silicon chip 4 and the conductor wiring 3 connected to each display segment or the grid electrode of the display unit 2 are electrically connected by wire bonding or the like using the wire wire 6. Then, an ordinary grid electrode and filament cathode (not shown) are provided above the fluorescent surface on the glass substrate 1.
By arranging, the electrons emitted from this filament cathode are controlled by the grid electrode and each display segment is controlled.
2a to 2e are made to emit light by making them incident. In this case, a metal cap 7 is attached to the silicon chip 4 on the glass substrate 1 via a metal frame 8 in order to block the incidence of an electron beam or light to the chip, as shown in FIG. ing.

[Problems to be solved by the invention]

However, in the conventional fluorescent display tube having such a structure, the maximum number of bonding wires is limited by the number of bonding pads 5 that can be arranged around the silicon chip. Further, since the silicon chip is die-bonded on the same substrate on which the display segments 2a to 2e are formed, the space becomes a dead space for display. Further, since external light or the like is directly incident on the silicon chip 4, it is necessary to shield the light with the metal cap 7 or the like.

The present invention has been made in view of the above point, and an object thereof is to provide a chip-in-glass type fluorescent display tube which solves the above-mentioned conventional problems by arranging an anode substrate and a driving IC chip in three dimensions. To provide.

[Means for solving problems]

In order to achieve such an object, a fluorescent display tube according to the present invention includes a vacuum container including a substrate such as glass and an envelope sealed on the substrate, and an inside of the envelope. An anode substrate, which is disposed opposite to the substrate and in which a display portion composed of display segments made of a fluorescent material is formed, and a grid electrode and filament which are sequentially disposed above the fluorescent surface on the anode substrate. A cathode and a driving IC chip mounted on the substrate on the back side of the anode substrate and electrically connected to drive the display unit, and the anode substrate is provided with each display segment of the display unit on its back surface. Correspondingly formed conductor wiring pads, these pads and drive IC
It is characterized in that it is electrically connected to a connection pad formed in the central portion of the surface of the chip by a connection pin.

[Action]

Therefore, in the present invention, the anode substrate is provided inside the envelope, the driving IC chip is arranged on the back side opposite to the fluorescent surface of the anode substrate, and electrically connected by the connection pin. As a result, the anode substrate and the driving IC chip can be arranged three-dimensionally in the vertical direction, and furthermore, the incidence of electron beams and external light on the driving IC chip can be blocked by the anode substrate.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a sectional view showing a schematic structure of a chip-in glass type fluorescent display tube according to an embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a chip mounting substrate made of glass or the like, and the central portion of the surface of the substrate 11 is a driving IC chip to be described later.
21 is die-bonded, and the IC chip driving conductor wiring 12 is formed on the peripheral surface thereof with a predetermined pattern. Further, on the substrate 11, an envelope 15 composed of a translucent windshield 13 and a spacer 14 formed to surround the peripheral side surface thereof is sealed, and the substrate 11 and the envelope are enclosed. A vacuum container is formed by 15. An anode substrate (also referred to as a segment substrate) 16 is attached to the central portion of the side surface of the spacer 14 that constitutes the envelope 15 so as to face the substrate 11 with a predetermined space. This anode substrate
Reference numeral 16 is made of ceramics or glass, and a dot-shaped display segment 17 made of a fluorescent substance is arranged in a matrix on the surface thereof to form a dot matrix display portion 18, and the display portion 18 is formed on a part of the back surface thereof. Conductor wiring 19 from each display segment 17 as an anode constituting the is formed by gathering using a multilayer wiring technology or the like, these conductor wiring 19 of the driving IC chip 21 via the connection pin described later. It is supposed to be conductively connected to each output band.

Further, on the anode substrate 16, a normal grid electrode 42 and a filament cathode 41 are arranged with a predetermined interval corresponding to the pattern of the dot matrix display portion 18, and emitted from the filament cathode 41. The generated electrons are accelerated, diffused, or selectively controlled by the grid electrode 42 to be incident on the fluorescent surface of the dot matrix display portion 18, so that the fluorescent surface side is used as a display surface and is similar to a conventional fluorescent display tube. It is supposed to do a dot matrix display. Note that 43 and 44 are a pair of filament supports, each of which comprises a support for supporting the filament cathode 41 and an anchor.

On the other hand, the driving IC chip 21 or silicon chip 21 die-bonded on the substrate 11 is basically the same as that of the conventional example shown in FIG. 6, but its pad structure is different, and the chip is different. An input bonding pad 22 is formed in the peripheral portion, and an output bonding pad 23 to each of the display segments 17 is formed in the central portion of the chip. Then, the input bonding pad 22 on the silicon chip 21 and the conductor wiring 12 thereof are connected by wire bonding or the like using the wire wire 24, and the ends of the conductor wiring 12 are passed through the lead pins 25 as external terminals to form a vacuum container. It has been pulled out. Further, the output bonding pad 23 for each display segment on the silicon chip 21 and the conductor wiring pad 26 (FIG. 2) from each display segment 17 formed on the back surface of the anode substrate 16 are accurately positioned. The connection pins 27 are electrically connected to each other. At this time, the connection pin 27 is made of a thin wire made of a material such as tungsten, stainless steel, carbon, gold, aluminum (Al), and has a predetermined elasticity.

Next, an example of a method of connecting the anode substrate 16 and the silicon chip 21 using the connection pins 27 will be described with reference to FIGS. Here, first, the connection pin 27 and the anode substrate
As shown in FIG. 2 (a), the connection with the insulating base 32 is made of ceramics and the connecting pins 27 are connected to the base 32. As shown in FIG.
For a pin guide including a guide hole 33 formed corresponding to each of the above and a fixing member 34 having a hole portion 35 formed integrally with the back surface of the base body 32 and formed corresponding to each connecting pin 27 thereof. Using the plate 36, the fixing member
One end of each connecting pin 27 is inserted through each hole 35 of 34 to penetrate the guide hole 33 and project a part thereof, and these connecting pins 27 are connected to the pin guide plate.
Fix to 36 at once. Then, by fixing this plate 32 to the back surface of the anode substrate 16 with an adhesive 37 such as a glass frit, one end of each connection pin 27 is provided with a conductor wiring from each display segment 17 formed on the back surface of the anode substrate 16. The pads 26 can be brought into contact with each other and electrically connected. As another means, as shown in FIG. 2B, one end of each connection pin 27 is brazed to a conductor wiring pad 26 from each display segment 17 formed on the back surface of the anode substrate 16. Alternatively, the conductive paste 38 may be fixed and directly connected. In FIG. 2 (b), 39 is an intermediate pad provided on each of the conductor wiring pads 26.

Next, when the silicon chip 21 and the connection pin 27 are connected, it is very difficult to realize with the conventional pad structure of the silicon chip. The reason is that the conventional pad structure of the silicon chip 4 has a very thin passivation film 28a of about 1 μm and its through holes 2 as shown in FIG.
The passivation film 28a is made of an inorganic material such as a glassy film called PSG or a SiN film, as shown in FIG. 1. This is because if the connection pin 27 or the like comes into contact with the passivation film 28a, cracking or the like occurs, which causes chip defects. The embodiment according to the present invention is realized by improving this point, and the pad structure of the silicon chip 21 is shown in FIG.

In FIG. 3, the passivation film on the silicon chip 21 is coated with, for example, PIQ-L100 (trade name) as a low thermal expansion polyimide layer 28 in place of the PSG or SiN film, or further thereon. Conventional polyimide is several μm
Although the limit stress was reached between silicon and the PIQ-L100, the coating was possible with a thickness of about 50 μm. Further, its thermal decomposition temperature is 450 ° C. or higher, which is sufficiently higher than the sealing temperature of the fluorescent display tube, and gas generation or the like due to decomposition does not occur. Then, on this polyimide layer 28,
An aluminum pad 30 having a film thickness of 2 to 3 .mu.m is adhered and formed through the through hole 29 as shown in FIG. Even if the aluminum pad 30 is left as it is, there is no problem if all the connection pins 27 come into contact with each other, but if there is even one connection pin 27 that does not reach the aluminum pad 30, as shown in FIG. In order to solve this point, in this embodiment, as shown in FIG. 3, a conductive powder such as ZnO: Zn or carbon or a paste layer 31 was formed on the aluminum pad 30 by an electrodeposition method or the like. As a result, even if there are connection pins 27 that are not in contact with the aluminum pad 30, all the connection pins 27 can be electrically connected to the aluminum pad 30 through the conductive powder or paste layer 31 of the connection pad 27, which results in good electrical continuity. Can be obtained.

In FIG. 1, for convenience of explanation, the anode substrate 16 is shown as being provided with only conductor wirings corresponding to the respective display segments 17, but grid conductor wirings connected to the grid electrodes 42 are also formed at the same time. Then, the conductor wiring pads and the output pads 23 on the silicon chip 21 can be conductively connected by using the connection pins 27 in the same manner as described above.

As described above, according to the chip-in-glass type fluorescent display tube of the above-mentioned embodiment, since the silicon chip 21 is arranged below the anode substrate 16, there is no restriction on the display space factor. This makes it possible, for example, to drive a dot matrix display of equal pitch by dividing it into several chips. Further, by arranging the output pad 23 in the central portion on the silicon chip 21, the number of outputs from one chip is dramatically increased, and moreover, a large number of connecting pins 27 are once connected to the pin guide plate 36. Since it can be conductively connected to, the time required for bonding can be greatly reduced. further,
Since the silicon chip 21 is arranged on the back surface of the anode substrate 16 opposite to the fluorescent surface, it becomes easy to prevent irradiation of electron beams and incidence of external light, and the metal cap 7 for shielding as shown in FIG. Etc. can be omitted.

〔The invention's effect〕

As described above, according to the chip-in-glass type fluorescent display tube of the present invention, the anode substrate on which the display portion of the fluorescent body is formed and the driving IC chip are separated, and these are vertically arranged three-dimensionally. With the structure in which the connection pins are electrically connected, there is no restriction on the display space factor, and the number of outputs from one chip can be increased. Further, since the anode substrate can prevent the electron beam and the external light from entering the driving IC chip, the shielding member for the shield becomes unnecessary. Also, by using the structure in which the connection pins are electrically connected, it is possible to obtain good electrical continuity between the anode substrate and the driving IC chip without any defective electrical continuity, thus ensuring reliable electrical connection. It has the effect of making it possible.

[Brief description of drawings]

FIG. 1 is a sectional view of a schematic structure showing an embodiment of a fluorescent display tube according to the present invention, and FIGS. 2 (a) and 2 (b) are connection states of an anode substrate and connection pins in a dotted line portion A of FIG. FIG. 3 is a partial detailed sectional view showing a connection state between the silicon chip and a connecting pin in a dotted line portion B of FIG. 1, and FIG. 4 is a pad on a silicon chip according to a conventional example. FIG. 5 is a partial cross-sectional view showing the structure, FIG. 5 is a plan view showing an arrangement structure of a silicon chip on a glass substrate according to a conventional example, and FIG. 6 shows a bonding state of the silicon chip at the one-dot chain line A in FIG. FIG. 7 and FIG. 7 are cross-sectional views of a metal cap portion for blocking the incidence of an electron beam or light on a silicon chip according to a conventional example. 11 …… Chip mounting board, 12 …… IC chip drive conductor wiring, 13 …… Windshield, 14 …… Spacer, 15 …… Envelope, 16 …… Anode board, 17 …… Display segment, 18… …
Display, 19 …… Segment conductor wiring, 21 …… Drive IC
Chip (silicone chip), 22 ... Input bonding pad, 23 ... Output bonding pad, 24 ... Wire wire, 25 ... Lead pin, 26 ... Conductor wiring pad, 27
...... Connecting pin, 28 …… Polyimide layer, 29 …… Through hole, 30 …… Aluminum pad, 31 …… Conductive powder or paste layer, 36 …… Connecting pin guide plate, 37 …… Adhesive material, 41 …… Filament cathode, 42 ... Grid electrode.

Claims (3)

[Claims] 1. A vacuum container comprising a substrate such as glass and an envelope sealed on the substrate; a fluorescent container disposed inside the envelope so as to face the substrate; An anode substrate on which a display section composed of display segments is formed, a grid electrode and a filament cathode sequentially arranged above the fluorescent surface on the anode substrate, and mounted on the substrate on the back side of the anode substrate. And a driving IC chip electrically connected to drive the display unit, and the anode substrate has conductor wiring pads formed on the back surface thereof in correspondence with the display segments of the display unit. Then
A fluorescent display tube characterized in that these pads and a connecting pad formed in the central portion of the surface of the driving IC chip are electrically connected by connecting pins. 2. The connection pin is made of tungsten, stainless steel,
The fluorescent display tube according to claim 1, characterized in that the fluorescent display tube is composed of thin wires such as gold wires and aluminum wires, and has a structure in which they are collectively fixed to the pin guide plate. 3. The driving IC includes a silicon chip as a chip, and a connection pad formed on the silicon chip has a low thermal expansion polyimide layer for protecting the surface of the silicon chip and a metal such as aluminum. 3. The fluorescent display tube according to claim 1 or 2, wherein the connecting pad is formed of a conductive powder or a paste layer such as ZnO: Zn or graphite formed thereon. .