JPH06236741A - Fluorescent character display device - Google Patents

Abstract

PURPOSE:To integrate also a quartz oscillator into the envelop of a fluorescent display display device. CONSTITUTION:A phosphor display part 26 is formed on a glass base 22 constituting the lower surface of an envelop 21 through an anode 25, and a circuit element mounting part 28 is also formed. An IC chip 29 is mounted on the circuit element mounting part 28, and a bare quartz oscillator 30 is directly mounted thereon. These IC chip 29 and quartz oscillator 30 are covered with a shield cover 40 to protect them from the thermions emitted from a filament 39. The periodic pulse signal generated in the quartz oscillator 30 is inputted to the IC chip 29, and used as the clock signal for conducting time display, or as the clock signal for synchronizing the operation of a CUP formed on the IC chip 29. When the phosphor display part 26 is dynamically driven, a one obtained by dividing the clock signal is used as the timing pulse of switching of a lighting segment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called chip-in-glass type (hereinafter abbreviated as "CIG type") fluorescent display in which a phosphor display section and a circuit element mounting section are arranged in a vacuum envelope. It relates to the device.

[0002]

2. Description of the Related Art Generally, in a CIG type fluorescent display device, a driving IC chip that constitutes a driving circuit is mounted on a substrate, and a power source and a control signal are externally applied to the driving IC chip to cause a fluorescent light on the substrate. It is designed to drive the body display unit. This CIG type fluorescent display device displays, for example, time and various information according to an input control signal, and a periodic pulse generated by a crystal oscillator as a clock signal for controlling these displays. Signal is used.

Conventionally, for example, as shown in FIG. 7, a crystal oscillator 11 is enclosed in a nickel-white holder 12, and a lead wire 13 is drawn out from the holder 12, which is used. Was disposed on a control substrate provided outside the fluorescent display device.

[0004]

In recent years, in the CIG type fluorescent display device, in order to reduce the number of leads and the number of external parts, circuit elements such as resistors and capacitors are also mounted on chip parts, thick film printing, etc. Some of them are incorporated in the envelope of the fluorescent display device. Similarly, it is ideal that the crystal unit be incorporated in the envelope of the fluorescent display device, but in the case of the conventional structure as shown in FIG.
However, because the cage 12 made of nickel silver cannot withstand the high temperature treatment in the assembling process, it cannot be incorporated in the envelope of the fluorescent display device. Therefore, at present,
There was no choice but to install a crystal unit outside, which was an obstacle to reducing the number of leads and external parts.

The present invention takes such a situation into consideration,
An object of the invention is to provide a fluorescent display device in which a crystal oscillator is also incorporated in the envelope.

[0006]

In order to achieve the above object, a fluorescent display device of the present invention is provided with a phosphor display portion and a circuit element mounting portion on a substrate, and these are housed in a vacuum envelope. In the above-mentioned one, a crystal resonator is mounted in a bare state on the circuit element mounting portion.

[0007]

[Function] The inside of the envelope of the fluorescent display device is in a vacuum state and is less susceptible to the influence of the external environment (the envelope can also be used as a holder for a crystal unit).
Focusing on, the crystal oscillator is directly mounted on the circuit element mounting portion of the substrate inside the envelope in a bare state without being put in the holder. This greatly contributes to the reduction in the number of leads and the number of external parts, and also allows the crystal oscillator to stably operate under excellent environmental conditions in the envelope.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. The envelope 21 is sealed in a vacuum state by bonding a cover glass 24 to a glass substrate 22, which is a substrate, via a spacer glass 23. The glass substrate 2
2, an anode 25 is formed by, for example, a thin film printing technique, and a phosphor display portion 26 is formed on the upper surface of the anode 25 by printing or the like. This phosphor display unit 26 is
It is covered with a mesh grid 27 provided on the glass substrate 22.

A circuit element mounting portion 28 is formed on the right side of the glass substrate 22, and an IC chip 29 is mounted on the circuit element mounting portion 28 by a wire bonding method. The IC chip 29 has a circuit of a microcomputer having a CPU, a RAM, etc., and the phosphor display unit 2
A driving circuit for driving 6 is collectively formed, and is connected to a wiring pattern (not shown) formed on the glass substrate 22 by a bonding wire 44. Characters and the like are displayed by applying a drive signal output from the IC chip 29 to the anode 25 (phosphor display unit 26) through the wiring pattern.

Further, the crystal unit 30 is mounted on the circuit element mounting portion 28 in a bare state. This crystal unit 3
As shown in FIG. 3, 0 is the electrode film 31, 32 on both upper and lower surfaces.
Are formed by vapor deposition or the like, and both ends of the crystal unit 30 are two spacers 3 provided on the circuit element mounting portion 28.
It is placed on 3, 34. And the crystal unit 30
The terminal portions 31a and 32a of the electrode films 31 and 32 on both surfaces are led out to the same side, and correspondingly, the spacer 33 on one side is formed with connection ports 35 and 36. Through the connection ports 35 and 36, the terminal portions 31 of the electrode films 31 and 32
a and 32a are connected to a wiring pattern (not shown) on the circuit element mounting portion 28 by conductive adhesives 37 and 38 such as silver paste and conductive glass. As a result, the crystal unit 30 is electrically connected, only one end of the crystal unit 30 is fixed, and the other end is in a vibration free state.

The crystal unit 30 and the IC chip 29 are
In order to protect from the thermoelectrons emitted from the filament 39 (see FIGS. 1 and 2), it is covered with a conductive shield cover 40 provided in the circuit element mounting portion 28. The filament 39 is stretched over the shield cover 40 and the grid 27, and both ends thereof are fixed to the supporting electrodes 41 and 42 provided on the glass substrate 22 by welding or the like. As shown in FIG. 2, a plurality of leads 43 are provided on the side edge portion of the glass substrate 22, and the crystal unit 30 and the crystal unit 30 are externally connected through the leads 43.
A power supply voltage, a control signal and the like are given to the C chip 29.

The operating principle of the CIG type fluorescent display device constructed as described above is as follows. That is, by supplying an electric current to the filament 39 through the supporting electrodes 41 and 42, the filament 39 is heated to radiate thermoelectrons toward the phosphor display unit 26, and at the same time, the mesh grid 2
A positive voltage is applied to 7 to accelerate the thermoelectrons. In this state, when a positive voltage is selectively applied to each anode 25 (each phosphor display unit 26) by the drive signal output from the IC chip 29, the surface of the phosphor display unit 26 to which the positive voltage is applied is The accelerated electrons collide with each other to generate an excited light emission phenomenon and display characters and the like.

At this time, the crystal oscillator 30 is applied with an AC voltage through the electrode films 31 and 32 on both sides, oscillates at a predetermined resonance frequency to generate a periodic pulse signal, and the periodic pulse signal is generated by the IC. Input to chip 29. This periodic pulse signal is used as a clock signal for time display, as a clock signal for synchronizing the operation of the CPU formed in the IC chip 29, and R
When it is used as a clock signal for controlling the AM rewriting time or when the phosphor display unit 26 is dynamically driven, a divided frequency of the above clock signal is used as a timing pulse for switching the lighting segment. Become.

According to the first embodiment described above, the inside of the envelope 21 is in a vacuum state and is less susceptible to the influence of the external environment (the envelope 21 is held by the crystal oscillator 30). It can be used also as a container), so that the crystal unit 30 is directly mounted on the circuit element mounting portion 28 of the glass substrate 22 in the envelope 21 in a bare state without being put in the holder. As a result, it can greatly contribute to the reduction of the number of leads and the number of external parts, and can meet the demand for compactness and low cost.

By the way, when the accuracy of the clock signal generated by the crystal unit 30 is lowered, the error of the display time becomes large, the CPU and the RAM malfunction, and the display of the dynamic drive becomes scattered. Therefore, how to improve the oscillation accuracy of the crystal unit 30 is an important technical issue.

In this respect, according to the first embodiment, since the crystal oscillator 30 is mounted in the envelope 21 kept in a vacuum state, the crystal oscillator 30 is placed in the external environment (outside air / humidity). -Stable operation can be performed in an ideal environment that is unlikely to be affected by atmospheric pressure, temperature, and dust. By the way, the density of air changes depending on the environmental conditions such as atmospheric pressure and temperature, and the air resistance during vibration also changes.Therefore, when a quartz oscillator is vibrated in the atmosphere, the air resistance changes due to changes in the environmental conditions. However, since the crystal oscillator 30 is vibrated in a vacuum in the first embodiment, the air resistance during vibration is zero, and the oscillation frequency can be stabilized. . Moreover, the crystal unit 3
By placing 0 in a vacuum, it is possible to prevent the crystal oscillator 30 from being contaminated or corroded by moisture or dust in the atmosphere, contributing to stabilization of oscillation characteristics and improving durability and reliability.

In the first embodiment, the crystal unit 30 is used.
However, the crystal unit 30 may be fixed at both ends as in the second embodiment of the present invention shown in FIG. In the second embodiment, the terminal portions 31a, 3 of the electrode films 31, 32 on both surfaces of the crystal unit 30 are arranged.
2a is led out to the opposite side, and correspondingly, the connection openings 35 and 36 are formed in the spacers 33 and 34 on both sides, respectively. Wiring patterns (not shown) on the circuit element mounting portion 28 are connected to the terminal portions 31a and 32a of the electrode films 31 and 32 through the connection ports 35 and 36 with a conductive adhesive 37 or 38 such as silver paste or conductive glass. ) To fix both ends of the crystal unit 30. Also in this case, the first
As in the embodiment, the crystal resonator 30 is vibrated by utilizing the gap between the spacers 33, 34 on both sides.

In each of the first and second embodiments described above, the crystal resonator 30 is electrically connected and fixed by the conductive adhesives 37 and 38. However, the present invention shown in FIGS. As in the third and fourth embodiments,
The electrical connection of 0 may be made by the bonding wires 50, 51, and the fixing may be made by the adhesives 54, 55. In the third embodiment of FIG. 5, as in the first embodiment, the terminal portions 31a and 32a of the electrode films 31 and 32 of the crystal unit 30 are formed.
Is connected to one end, and the terminal portions 31a and 32a are connected to the wiring patterns 52 and 53 on the circuit element mounting portion 28 by the bonding wires 50 and 51.
One end of is fixed to the spacer 33 on one side by an adhesive 54 such as silver paste.

On the other hand, in the fourth embodiment of FIG. 6, as in the second embodiment, the terminal portions 31a and 32a of the electrode films 31 and 32 of the crystal unit 30 are led out to both ends, and the terminal portions 31a and 3 are formed.
2a and wiring patterns 52 and 53 on the circuit element mounting portion 28
And bonding wires 50 and 51 to connect
Both ends of the crystal unit 30 are provided with adhesives 54, 5 such as silver paste.
It is fixed to the spacers 33 and 34 on both sides by 5.

Besides, the present invention is not limited to the above-mentioned respective embodiments, and for example, the crystal resonator 30 may be electrically connected by a combination of a conductive adhesive and wire bonding, and the spacer 33 may be used. , 34 may be formed by using a lead frame or may be formed by thick film printing or the like.
Further, in the first embodiment, the circuit of the microcomputer and the drive circuit are collectively formed on one IC chip 29, but these circuits are formed on different IC chips to form the circuit element mounting portion 28. Alternatively, a plurality of IC chips may be mounted.

[0021]

As is apparent from the above description, according to the present invention, the inside of the envelope of the fluorescent display device is in a vacuum state, and it can be used as a holder for a crystal oscillator. In order to reduce the number of leads and the number of external parts, the crystal unit was directly mounted directly on the circuit element mounting part of the board inside the envelope without putting it in the holder. In addition to being able to greatly contribute to meeting the demands for compactness and cost reduction, the crystal unit can be operated stably under excellent environmental conditions inside the envelope, improving its characteristics. It can also contribute to improving reliability.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a fluorescent display device showing a first embodiment of the present invention.

FIG. 2 is a plan view showing a fluorescent display device partially broken away.

FIG. 3 is an enlarged perspective view showing a mounted state of a crystal unit.

FIG. 4 is a view corresponding to FIG. 3 showing a second embodiment of the present invention.

FIG. 5 is a view corresponding to FIG. 3 showing a third embodiment of the present invention.

FIG. 6 is a view corresponding to FIG. 3 showing a fourth embodiment of the present invention.

FIG. 7 is a perspective view showing a conventional crystal resonator sealing structure.

[Explanation of symbols]

21 ... Envelope, 22 ... Glass substrate (substrate), 25 ... Anode, 26 ... Phosphor display section, 27 ... Grid, 28 ... Circuit element mounting section, 29 ... IC chip, 30 ... Crystal oscillator,
31, 32 ... Electrode films, 33, 34 ... Spacers, 37, 3
8 ... Conductive adhesive, 39 ... Filament, 40 ... Shield cover, 44, 50, 51 ... Bonding wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Koji Numazaki, 1-1, Showa-cho, Kariya city, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Inventor, Tetsuo Fujii, 1-1, Showa-cho, Kariya city, Aichi prefecture (72) Inventor Masaaki Kobayashi 3-36 Noritake Shinmachi, Nishi-ku, Nagoya-shi Noritake Company Limited Limited (72) Inventor Yasuyuki Kani 3-36 Noritake Shincho, Nishi-ku, Nagoya-shi Noritake Co., Ltd. Company Limited (72) Inventor Shunichi Matsumoto 2160, Yatsunami, Sansu, Yasu-cho, Asakura-gun, Fukuoka 2160 Address, Kyushu Noritake Co., Ltd. 2160 Address, Kyushu Noritake Co., Ltd. (72) Inventor Jun Mohri, Yakusu, Yasu Town, Asakura District, Fukuoka Prefecture Kyushu Noritake Co., Ltd. in

Claims (1)

[Claims] 1. A fluorescent display device in which a substrate is provided with a phosphor display section and a circuit element mounting section, and these are housed in a vacuum envelope, and the circuit element mounting section has a crystal resonator in a bare state. A fluorescent display device characterized by being mounted.