JP2715970B2 - Drive circuit integrated type fluorescent display tube optical head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent display tube optical head integrated with a driving circuit, and more particularly to a fluorescent display tube having a high-definition pixel electrode in an optical head and a display using the fluorescent display tube.

[0002]

2. Description of the Related Art Fluorescent display tubes are widely used as displays for home electric appliances and the like, and are expected to be applied to other products such as optical heads of printers. In particular, since high brightness can be obtained over the entire visible light range at low cost, application as a color light source such as a color optical head is expected. In the conventional fluorescent display, in order to achieve high definition, there are problems such as the number of connection lead lines being enormous, or the need for a high voltage to compensate for the decrease in luminance due to the duty driving with a voltage. there were. In order to solve this problem, a driving circuit integrated type fluorescent display tube in which a driving circuit is formed in a vacuum envelope has been proposed (for example, Japanese Patent Laid-Open No. 3-403).
47).

[0003] The structure of a driving circuit integrated type fluorescent display tube basically includes a cathode, a grid, a phosphor (anode), and a driving circuit. FIG. 3 (a) shows the prior art.
(B) and (c). FIG. 3A is a sectional view of the structure of an optical head using a driving circuit-integrated fluorescent display tube, FIG. 3B is an enlarged sectional view of a phosphor electrode portion, and FIG. In the figure, a conventional optical head using a driving circuit-integrated fluorescent display tube has a cathode (2), a driving circuit board (3), and a grid (4) formed in a vacuum envelope (1). I have.

As the driving circuit substrate (3), a method using a silicon chip and a method using a thin film driving circuit using a glass substrate have been reported. However, the use of a glass substrate is preferred in terms of cost and length. It is advantageous. A drive circuit (6) is formed on the drive circuit board (3), and is electrically connected to the drive circuit (6) by the pixel electrode (5) to form a phosphor (7). Further, a fixing jig (8) fixed to the vacuum envelope (1) so as to be in contact with the drive circuit board (3).
Is installed. As described above, the number of connections can be reduced by integrating the driving circuit, and the definition of the phosphor pixel electrode itself can be improved by a lithography technique using a semiconductor.

[0005]

However, in the prior art, even if the phosphor pixel electrode can be formed with high definition, it is difficult to pattern the phosphor itself formed thereon with high precision. However, there is a problem that a fluorescent display tube cannot be obtained. This is because the phosphor is composed of particles of several tens of μm, so that it is difficult to form a pattern of the same size. At present, at most 100 μm
Only a weak pattern accuracy is obtained, and the pattern edge is not good. When the application to the printer head is simply considered, the resolution is about 8 dots / mm. At present, a resolution twice or more than this is required, and there is a problem that it is difficult to meet this demand with the current technology.

[0006]

According to the present invention, there is provided a vacuum envelope made of glass or the like, a pixel electrode array provided in the vacuum envelope, a phosphor formed thereon, A fluorescent circuit comprising a driving circuit connected to electrodes, a grid electrode, a cathode electrode, and a connection terminal fixed to the vacuum envelope and installed in contact with a part of the driving circuit; A fluorescent display tube comprising: an insulating electron intrusion prevention film that covers the body and has an opening on a phosphor of a desired pixel electrode portion. Further, the present invention is the fluorescent display tube described above, wherein a photosensitive coating film such as an organic resist or a photosensitive polyimide is used as the insulating electron intrusion prevention film.

[0007]

According to the present invention, by providing an insulating electron intrusion prevention film (an insulating film layer serving as an electron prevention film) which covers the fluorescent material and has an opening on the fluorescent material in the pixel electrode portion, a high-resolution fluorescent light is provided. A display tube optical head can be formed, and a resolution higher than the pattern accuracy of the phosphor can be obtained.
A resolution of I can be achieved. In addition, by using a photosensitive coating film such as an organic resist as the insulating electron intrusion prevention film, an electron intrusion prevention film can be easily formed on the phosphor, and the formed insulating electron intrusion prevention film is carbonized. Since it is an organic film that has sufficient insulation, it has better conductivity and thermal conductivity than glass, and has a charge-up prevention and heat dissipation effect.

[0008]

Embodiments of the present invention will be described with reference to the drawings. Embodiment 1 FIG. 1 (a) shows a first embodiment of the present invention.
(B) and (c). 1A is a structural sectional view of the device of the first embodiment, FIG. 1B is an enlarged sectional view of the phosphor electrode portion of FIG. 1A, and FIG. 1C is a plan view of the device of FIG. is there.

As shown in FIGS. 1 (a), 1 (b) and 1 (c), a filamentary cathode (2) and a drive circuit board (3) made of non-alkali glass are placed in a vacuum envelope (1) made of soda glass. ), A grid (4) is installed, and the drive circuit board (3) is installed on a vacuum envelope board.
A drive circuit (6) composed of a thin film transistor is formed on the drive circuit board (3), and is electrically connected to the drive circuit (6) by the pixel electrode (5) to form a phosphor (7). ing. The entire surface of the drive circuit is coated with an insulating film (10), and an opening is provided only in the pixel electrode portion. An insulating electron intrusion prevention film (9) is formed in the upper layer of the phosphor, and only the pixel electrode portion of the phosphor is opened. When a grid is formed on the external connection pad or the drive circuit board, the pad and the grid are also resist openings.

Next, the operation mechanism of the driving circuit integrated type fluorescent display tube shown in FIG. 1 will be described. The thermoelectrons generated at the cathode (2) are accelerated by the grid (4) having a positive potential with respect to the cathode (2), and are emitted toward the drive circuit board (3). When the potential of the phosphor (7) is positive with respect to the cathode (2), the emitted thermoelectrons collide with the phosphor (7) to emit light. By controlling the potential of each phosphor by the drive circuit 6, only the phosphor at a desired position can emit light. Here, only the electrode portion is opened without being covered with the insulating electron intrusion prevention film (9). Electrons are irradiated on the phosphor only at this opening to emit light. The fluorescent material that has protruded outside the electrode is prevented from entering electrons by the insulating electron intrusion prevention film, and thus does not emit light. Therefore, a light source with high resolution can be realized even if the phosphor is not patterned with high resolution.

In the first embodiment, an organic resist is used as the insulating electron penetration preventing film (9). Although any insulating film can be used to achieve the functions of the present invention, it is extremely difficult to form an insulating film on a phosphor by a CVD (chemical vapor deposition) method, a sputtering method, or the like. Further, since the phosphor is deteriorated by moisture or the like, the number of processes after the formation of the phosphor must be reduced as much as possible. Since the resist can be formed only by the development process after the coating, the process is most suitable for the process after the phosphor is formed. Since a photosensitive organic resist used in a normal semiconductor process is used, high-resolution patterning can be performed by a lithography process.

In addition, a resist material having excellent compatibility with the phosphor or a photosensitive insulating material may be used. Since the phosphor is weak to an organic solvent, baking is sufficiently performed before forming and developing a resist. The resist is finally baked and carbonized so as not to cause problems such as outgassing in a vacuum. In this carbonized state, the resist becomes blackish brown, so that multiple reflection on the glass surface is suppressed, and deterioration of contrast is prevented.

Embodiment 2 FIGS. 2 (a), 2 (b) and 2 (c) show a second embodiment of the present invention. In the second embodiment,
Further, an example will be described in which an auxiliary electrode is provided on the outer peripheral portion of the electrode. FIG. 2A is a structural sectional view of the device of the second embodiment, FIG. 2B is an enlarged sectional view of the phosphor electrode portion of FIG.
(C) is a plan view as seen from the upper surface of the device of (b).
As shown in FIGS. 2 (a), 2 (b) and 2 (c), a filamentary cathode (2), a drive circuit board (3) made of non-alkali glass, and a grid are placed in a vacuum envelope (1) made of soda glass. (4) is installed, and the drive circuit board (3) is installed on the vacuum envelope board.

A drive circuit (6) composed of a thin film transistor is formed on the drive circuit board (3), and is electrically connected to the drive circuit (6) by a pixel electrode (5) to form a phosphor (7). Are formed. The entire surface of the drive circuit is coated with an insulating film (10), and an opening is provided only in the pixel electrode portion. An insulating electron intrusion prevention film (9) is formed on the upper layer of the phosphor, and only the center of the pixel electrode of the phosphor (7) is opened. When a grid is formed on the external connection pad or the drive circuit board, the pad and the grid are also resist openings.

A guard ring (11) is formed so as to surround the pixel electrode (5). In this guard ring,
A negative bias voltage is applied to the phosphor electrode. At this time, the incoming electrons are repelled by the guard ring, and are focused only on the central portion of the phosphor electrode as shown in FIG. Since the infiltration preventing film (9) not only prevents the entry of the electrons into the fluorescent material protruding out of the electrode but also repels the electrons by the guard ring (11), the entry of the electrons is prevented. Does not emit light.

Therefore, a light source with high resolution can be realized even if the phosphor is not patterned with high resolution. The guard ring (11) also serves to focus electrons.
As a result, the luminous efficiency can be improved. Further, since entry of electrons into the insulating electron intrusion prevention film can be reduced, the effects of reducing charge-up and reducing damage to the insulative electron intrusion prevention film can be obtained.

The above-described first and second embodiments relate to a thin-film drive circuit made of a thin-film semiconductor on a drive circuit board and a fluorescent display tube made of a phosphor.
The present invention is useful not only for a device in which a drive circuit is integrally formed of a thin film semiconductor, but also for a device in which an IC chip is mounted in a vacuum envelope. In any case, the present invention can be applied to all fluorescent display tubes that require a high-definition phosphor electrode.

[0018]

According to the present invention, a high-resolution fluorescent display tube optical head can be formed in an optical head using a fluorescent display tube integrated with a drive circuit. Further, a resolution higher than the pattern accuracy of the phosphor can be easily obtained, and an optical head using the same can achieve a resolution of 400 DPI. Further, by using a photosensitive coating film such as an organic resist as the insulating electron intrusion prevention film, the electron intrusion prevention film could be easily formed on the phosphor. It was confirmed that the process compatibility with the phosphor was excellent. The formed insulative electron intrusion prevention film is a carbonized organic film, so it has sufficient insulation, but has better conductivity and heat conductivity than glass, and also has the effects of preventing charge-up and improving the heat dissipation effect. Have.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 shows a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum envelope 2 ... Cathode 3 ... Drive circuit board 4 ... Grid 5 ... Pixel electrode 6 ... Drive circuit 7 ... Phosphor 8 ... Fixing jig 9 ... Insulating electron intrusion prevention film layer 10 ... Insulating layer 11 ... Guard ring

Claims (2)

(57) [Claims] 1. A vacuum envelope made of glass or the like, a pixel electrode array installed in the vacuum envelope, a phosphor formed thereon, a driving circuit connected to the pixel electrode, In a fluorescent display tube including a grid electrode, a cathode electrode, and a connection terminal fixed to the vacuum envelope and provided in contact with a part of the drive circuit, the fluorescent display tube covers the phosphor, and includes a desired pixel. A fluorescent display tube having an insulating electron intrusion prevention film having an opening on a phosphor in an electrode portion. 2. The fluorescent display tube according to claim 1, wherein a photosensitive coating film such as an organic resist or photosensitive polyimide is used as the insulating electron intrusion preventing film.