JPH0676769A - Fluorescent character display device - Google Patents

Abstract

PURPOSE:To realize a high-brightness and uniform fluorescent character display at low power consumption, and achieve compactness of the whole body of a device by setting a distance between a filament and a fluorescent character display part to be small. CONSTITUTION:A fluorescent character display part 26 is formed on a glass substrate 22 composing a lower surface of a flat vacuum container 21 through an anode 25, and a semiconductor chip 28 for driving is mounted on it. The fluorescent character display part 26 is covered with a mesh of a grid 27, and the semiconductor chip 28 is covered with a shield cover 30 provided over the glass substrate 22 to be protected. This shield cover 30 is also provided with function as a filament support electrode by fixing one end of a filament 31 disposed on the grid 27 with it. A fixing position of the filament 30 can thus be a desired position on the same level as an upper surface of the shield cover 30 or lower than that, and the whole tube length can be short.

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 driving semiconductor chip are arranged in a flat vacuum container. It relates to the device.

[0002]

2. Description of the Related Art In a conventional CIG type fluorescent display device, as shown in FIGS. 6 and 7, an anode 12 (see FIG. 7) is provided on an upper surface of a glass substrate 11 which constitutes a lower surface of a flat vacuum container 10. A phosphor display portion 13 (display segment) is formed by printing or the like, and a semiconductor chip 14 for applying a drive signal to the phosphor display portion 13 (anode 12) is formed.
Are mounted on the same glass substrate 11. Filament support electrodes 15 are fixed to both ends of the glass substrate 11 in the longitudinal direction, and filaments 16 that emit thermoelectrons toward the phosphor display unit 13 are fixed to the upper ends of the filament support electrodes 15 by welding or the like. ing.

Below the filament 16, a phosphor display section 13 and a semiconductor chip 14 are located. In order to protect the semiconductor chip 14 from thermoelectrons emitted from the filament 16, the semiconductor chip 14 is It is covered by the shield cover 17. Further, a mesh-shaped grid 18 is arranged between the filament 16 and the phosphor display unit 13, and thermoelectrons emitted from the filament 15 are accelerated by the grid 18 to the phosphor display unit 13. It is configured to collide and excite it to emit light.

[0004]

Generally, in order to efficiently increase the emission intensity (display brightness) of the phosphor display unit 13, it is necessary to make the distance between the filament 16 and the phosphor display unit 13 as small as possible. There is.

However, in the above conventional structure, the shield cover 17 is interposed between the filament 16 and the semiconductor chip 14, and the filament 16 is arranged above the shield cover 17 with a space A (see FIG. 7). Therefore, the distance B between the filament 16 and the phosphor display unit 13 is inevitably large on the semiconductor chip 14 side, and the display brightness decreases near the semiconductor chip 14. Therefore, conventionally, in order to balance the overall brightness, it is necessary to purposely raise the height position of the filament 16 on the side opposite to the semiconductor chip 14, which has a drawback that the overall brightness is reduced. The brightness can be increased by increasing the potential difference between the filament 16 and the phosphor display unit 13, but for this purpose, it is necessary to increase the driving voltage, and as a result, the power supply device is complicated and expensive. Will be invited.

In order to solve such a drawback, a filament supporting electrode 15 is installed between the semiconductor chip 14 and the phosphor display portion 13, and the semiconductor chip 14 and the shield cover 17 are arranged outside the filament 16. A configuration is also conceivable, but in this configuration, the overall pipe length (width dimension) becomes long, which is against the demand for miniaturization.

The present invention has been made in consideration of such circumstances, and an object thereof is to allow a filament to be arranged close to the phosphor display portion and to realize a high-intensity and uniform fluorescent display. The object of the present invention is to provide a fluorescent display device that can contribute to downsizing of the entire device.

[0008]

In order to achieve the above object, the fluorescent display device of the present invention is arranged such that a fluorescent display portion and a filament are arranged to face each other in a flat vacuum container, and the fluorescent display device is driven. Of the semiconductor chip and a shield cover for covering the semiconductor chip, wherein one end of the filament is fixed to the shield cover so that the shield cover has a function as a filament supporting electrode.

[0009]

According to the above construction, since the shield cover has a function as a filament supporting electrode, it is not necessary to dispose the filament above the shield cover with a space, and the fixing position of the filament is fixed to the upper surface of the shield cover. It is possible to set the position to the same as or lower than that. As a result, the distance between the filament and the phosphor display unit can be reduced without being restricted by the CIG structure, and a design for obtaining optimized brightness can be achieved, and at the same time, the entire device can be obtained. It is possible to reduce the thickness. Moreover, since the shield cover also serves as the filament supporting electrode, the conventional space for disposing the filament supporting electrode becomes unnecessary, and the entire tube length can be shortened accordingly.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.
It will be described based on. The flat vacuum container 21 includes a cover glass 24 on a glass substrate 22 via a spacer glass 23.
Are joined together and sealed in a vacuum state. An anode 25 is formed on the glass substrate 22 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 a mesh grid 2 provided on the glass substrate 22.
Covered by 7.

On the other hand, on the right side of the glass substrate 22, a semiconductor chip 28 for driving is located outside the grid 27 and mounted by wire bonding. The semiconductor chip 28 is connected to a wiring pattern (not shown) formed on the glass substrate 22 with a bonding wire 29. The drive signal output from the semiconductor chip 28 is applied to the anode 25 (phosphor display section 26) through the wiring pattern to display characters and the like.

The semiconductor chip 28 has a glass substrate 22.
It is covered by a shield cover 30 made of a conductive member provided on the upper side. The shield cover 30 protects the semiconductor chip 28 from thermoelectrons and the like emitted from the filament 31 arranged on the grid 27, and also functions as a filament support electrode that supports the right end of the filament 31. In this case, the filament 31
The right end of is fixed to the upper side edge of the shield cover 30 by welding or the like. The shield cover 30 is connected to the ground side through the external connection terminal 32 formed integrally with the shield cover 30. On the other hand, the left end of the filament 31 is fixed to the filament supporting electrode 33 provided on the glass substrate 22 by welding or the like as in the conventional case. This filament support electrode 33
A positive voltage of about 2 V, for example, is applied to the.

Also in the first embodiment, the filament 31 is stretched in an inclined shape so that the shield cover 30 side (ground side) is slightly higher. This is because the voltage drop due to the internal resistance of the filament 31. This is because the potential changes depending on the position of the filament 31 and the radiation amount of the thermoelectrons also changes depending on the position of the filament 31. Therefore, by tilting the filament 31, the irradiation amount of the thermoelectrons to the phosphor display unit 26 (display Luminance) of the light source.

As shown in FIG. 2, a plurality of external connection terminals 34 are provided on the side edge portion of the glass substrate 22, and the semiconductor chip 2 is externally supplied through these external connection terminals 34.
A control signal, a power supply voltage, and the like to 8 are supplied.

The operating principle of this CIG type fluorescent display device is as follows.
It is as follows. That is, a positive voltage of, for example, about 2 V is applied between the filament support electrode 33 and the shield cover 30 to cause a current to flow through the filament 31, thereby heating the filament 31 and directing thermoelectrons toward the phosphor display unit 26. While radiating, a positive voltage is applied to the mesh grid 27 to accelerate the thermoelectrons. At this time, each anode 25 is driven by the drive signal output from the semiconductor chip 28.
When a positive voltage is selectively applied to each phosphor display unit 26, the accelerated thermoelectrons collide with the surface of the phosphor display unit 26 to which the positive voltage is applied, causing an excited light emission phenomenon,
Display characters etc.

According to the first embodiment having such a configuration, since the shield cover 30 has a function as a filament supporting electrode on the ground side, the filaments 31 are arranged above the shield cover 30 with a space. It is not necessary, and the fixed position of the filament 31 can be set at the same position as the upper surface of the shield cover 30. As a result, the distance between the filament 31 and the phosphor display unit 26 can be reduced without being restricted by the CIG structure, and a design for obtaining optimized brightness can be achieved. High-luminance and uniform fluorescent display can be realized with power consumption, and the entire device can be thinned. Moreover, since the shield cover 30 also serves as the filament support electrode on the ground side, the conventional space for arranging the filament support electrode on the ground side is unnecessary, and the overall tube length can be shortened by that much, and in combination with the above-described thinning It can also contribute greatly to downsizing of the entire device.

On the other hand, FIGS. 3 and 4 show a second embodiment of the present invention, and only different parts from the first embodiment will be designated by different reference numerals and described. That is, although the filament 31 is fixed to the upper surface of the shield cover 30 in the first embodiment, the welding piece 36 is formed by cutting and raising the side surface of the shield cover 35 in the second embodiment. The filament 31 is welded to. In this way, the height position of the filament 31 is adjusted to the shield cover 35.
Since it can be set at an arbitrary position lower than the upper surface of the shield cover 35, there is an advantage that the distance between the filament 31 and the phosphor display unit 26 can be reduced without being restricted by the height of the shield cover 35. is there.

In the second embodiment, the semiconductor chip 2
A chip component 37 for protecting 8 from input / output signals is mounted on the glass substrate 22, and this chip component 37 is also protected by the shield cover 35.

FIG. 5 shows the third embodiment of the present invention. In this third embodiment, the filament 31 is fixed to the shield cover 38 at the substantially central portion of the upper surface thereof by welding or the like, and the shield cover 38 is formed. Of these, the portion 38a corresponding to the end cool portion C (portion where thermoelectrons are not radiated) of the filament 31 is formed thin. As a result, a space is secured between the end-cooled portion C of the filament 31 and the thin-walled portion 38a of the shield cover 38 to prevent contact between them due to vibration. Moreover, by positioning the end cool portion C of the filament 31 on the shield cover 38, there is an advantage that the tube length can be shortened by the length of the end cool portion C as compared with the first embodiment.
The other points are the same as those of the first embodiment.

The present invention is not limited to the above embodiments, but the number of filaments 31 and the shield covers 30, 3 are not limited to the above.
The shapes and the like of 5, 5 and 38 may be appropriately changed, and a positive voltage may be applied to the shield covers 30, 35 and 38 (the shield covers 30, 35 and 38 are used as the positive electrode side filament supporting electrodes). Various modifications are possible without departing from the spirit of the invention.

[0021]

As is apparent from the above description, in the present invention, the shield cover has a function as a filament supporting electrode, so that the fixed position of the filament is the same as or lower than the upper surface of the shield cover. It is possible to position it, it is possible to reduce the distance between the filament and the phosphor display portion, it is possible to realize high brightness and uniform fluorescence display with low power consumption, and it is also possible to make the entire device thinner. Become. Moreover, since the shield cover also serves as the filament supporting electrode, the space for disposing the conventional filament supporting electrode is unnecessary, and the entire tube length can be shortened accordingly, and in combination with the above-mentioned thinning, the overall size of the device can be reduced. Can also contribute significantly.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a cover glass partially broken away.

FIG. 3 is a vertical sectional front view of a main part showing a second embodiment of the present invention.

FIG. 4 is a plan view showing a cover glass and a shield cover partially broken away.

FIG. 5 is a vertical cross-sectional view of a portion around a shield cover showing a third embodiment of the present invention.

FIG. 6 is a view corresponding to FIG. 2 showing a conventional example.

FIG. 7 is a view corresponding to FIG. 5 showing a conventional example.

[Explanation of symbols]

21 is a vacuum container, 22 is a glass substrate, 24 is a cover glass, 25 is an anode, 26 is a phosphor display unit, 27 is a grid, 28 is a semiconductor chip, 30 is a shield cover (ground side filament support electrode), 31 is A filament, 33 is a positive electrode side filament supporting electrode, 35 is a shield cover, 37 is a chip component, and 38 is a shield cover.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Takei 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd. (72) Inventor Tetsuo Fujii 1-1-cho, Showa-machi, Kariya city, Aichi Nidec (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 2160 Address, Yatsunami Kyushu Noritake Co., Ltd.

Claims (1)

[Claims] 1. A fluorescent display device in which a phosphor display section and a filament are arranged to face each other in a flat vacuum container, and a semiconductor chip for driving and a shield cover for covering the semiconductor chip are built in, A fluorescent display device characterized in that one end of the filament is fixed to the shield cover so that the shield cover has a function as a filament supporting electrode.