JPH0414842Y2 - - Google Patents

Description

[Detailed description of the invention] (1) Description of the field to which the invention pertains The present invention relates to a fluorescent display tube, in which a display part and a driving circuit part consisting of semiconductor elements are integrally formed on the same glass substrate, and the display part and the driving circuit part are integrally formed on the same glass substrate. This invention relates to a fluorescent display tube having a so-called "Chip on Glass" (hereinafter referred to as COG) structure in which a circuit section and a circuit section are provided in the same vacuum envelope.

(2) Description of conventional technology As a fluorescent display tube having a conventional COG structure, a structure as shown in the partially cutaway perspective view of FIG. 1 and the cutaway plan view of the main part of FIG. 2 has been provided. .

In the figure, a plurality of wiring films 2, an insulating film 3, and segment electrodes 4 are laminated and deposited on a glass substrate 1.
and an anode substrate 6 which also serves as a drive circuit section (hereinafter referred to as pad section) 5, and a pad section 5 on this anode substrate.
An external extraction lead 7 as an input terminal, and a so-called frame electrode group having a filament cathode 9 arranged at an appropriate distance from the grid 8 integrated with the external extraction lead 7 are placed, and the pad portion 5 is further provided with a frame electrode group. The IC chip 11 is mounted by a bonding method or the like, the entire board is sealed with low melting point glass in a light-transmitting vacuum-tight container 10, and the terminals of the external lead leads 7 are energized, and the IC chip 11 is mounted.
A structure is provided that drives a COG fluorescent display tube through the COG.

However, in conventional fluorescent display tubes having such a COG structure, malfunctions of the driving circuit sometimes occur during operation. The cause of this malfunction was malfunction of the IC chip 11 due to external light 20 entering from the light-transmitting vacuum-tight container 10 (hereinafter referred to as a cover glass).

Since the cover glass has no special treatment for this light incident, it is easy for the external light 2 to enter.
0 reaches the surface of the IC chip 11. In CMOS LSI chips, where leakage current caused by light is a problem, the electrical characteristics change due to this external light, which sometimes causes malfunctions.

Therefore, in a fluorescent display tube having a conventional COG structure, it is necessary to perform some kind of treatment to surround the IC chip 11 to protect it from external light in order to improve reliability.

(3) Purpose of the invention The present invention aims to provide a fluorescent display tube having a COG structure that eliminates the conventional problems as described above. The main feature is that a metal cover is provided to cover the entire IC chip 11, and this cover is bonded and held to the metal frame electrode group.

Hereinafter, the present invention will be explained in detail using examples.

(4) Description of structure and function of the invention FIG. 3 is a partially cutaway perspective view showing an embodiment of a fluorescent display tube having a COG structure according to the invention.

In the figures, the same members as in FIGS. 1 and 2 are denoted by the same reference numerals, and their basic roles are no different from those in the conventional method.

In the figure, a segment electrode 4 having a phosphor layer and a pad portion 5 electrically connected to a driving circuit IC chip 11 by a wire bonding method are provided on a glass substrate 1. IC chip 11
is die-boarded with heat-resistant polyimide resin, and is further connected to pad 5 by ultrasonic bonding using aluminum wire. On the other hand, a metal cover 30 is provided so as to completely cover the entire IC chip 11, and this cover 30 is welded to a metal support 35 that supports the filament cathode 9. This metallic cover 30 is provided to prevent external light from entering the IC chip 11 of the present invention. In this embodiment, a stainless steel cover was used and welded to a metal support 35 made of 426 alloy.

(5) Explanation of effects In the fluorescent display tube of the present invention manufactured in this way, the provision of the metal cover 30 prevents external light 20 entering from the surface of the cover glass 10 from reaching the surface of the IC chip 11. never reach,
It has now become possible to obtain a COG fluorescent display tube that has excellent features that prevent IC malfunctions from occurring due to external light.

In this embodiment, the metal cover 30 is bonded and fixed to the filament cathode support 35, but it is clear that the same effect can be obtained even if it is bonded to other frame electrode groups.

Furthermore, although this embodiment describes only the case where one IC element is mounted on a segment-type fluorescent display tube, it is also effective when mounting multiple chips on a dot-type fluorescent display tube. is clear.

[Brief explanation of the drawing]

1 and 2 are a partially cutaway perspective view and a cutaway plan view of essential parts showing an example of a conventional fluorescent display tube with a COG structure, and FIG. 3 is a fluorescent display tube with a COG structure according to the present invention. FIG. 2 is a partially cutaway perspective view showing one embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Glass substrate, 2... Wiring film, 3... Insulating layer, 4... Segment electrode, 5... Pad part,
6... Anode substrate, 7... External lead lead, 8
... Grid, 9 ... Filament cathode, 10 ...
...Cover glass (vacuum-tight container), 11...IC chip, 20...External light, 30...Metal cover,
35...Metal support.

Claims (1)

[Scope of utility model registration request] In a fluorescent display tube having a structure in which a display section having a phosphor layer and a circuit section for driving the display section are integrally formed on the same substrate, and the display section and the circuit section are provided in the same envelope. A fluorescent display tube characterized in that a metal cover covering the entire circuit portion is connected and fixed to an electrode member disposed within the envelope.