JP3024651U - Fluorescent display tube - Google Patents

Abstract

(57) An object of the present invention is to reliably prevent generation of luminance unevenness due to conduction by a through hole between a phosphor screen and a wiring pattern passing thereunder, thereby improving display quality. A wiring pattern (2) having an anode pad (3) deposited on a glass substrate (1), a wiring pattern (2 ') deposited on the glass substrate (1) and having a different potential from the wiring pattern (2), and a glass substrate 1 has an insulating layer 5 deposited on the surface excluding the anode pad 3 and a phosphor layer 6 deposited on the anode pad 3, and the wiring pattern 2 ′ intersects with the phosphor layer 6. It is arranged in a position not to.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a fluorescent display tube in which a wiring pattern formed on an insulating substrate is covered with an insulating layer formed as a thin film by a photolithography method, and more particularly to an arrangement structure of a wiring pattern and a phosphor layer. Is.

[0002]

[Prior art]

 Conventionally, as a method of forming an insulating layer of an anode substrate used for a fluorescent display tube by using a photolithography method, as shown in the cross-sectional view of the main part of FIG. 3, it is formed of Al or the like on a glass substrate 1 as an insulating substrate. An insulating paste, which is a mixture of a low melting point frit glass powder, a photosensitive liquid and a pigment, is printed and formed on the wiring pattern 2 and the anode pad 3, and the insulating layer is exposed to ultraviolet light through a photomask having a predetermined pattern. Then, the insulating layer 5 having the through holes 4 is formed by the photolithography method for development.

Next, the glass substrate 1 on which the insulating layer 5 is formed is baked at about 560 ° C. for about 30 minutes to 1 hour to thermally decompose and volatilize the photosensitive liquid material in the insulating layer 5, At the same time, the low melting point frit glass powder is melted and fixed to form an insulating layer. Next, the phosphor screen 6 on the positive electrode pad 3 in the through hole 4 is formed to prepare an anode substrate. A method of manufacturing such an anode substrate is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-40472.

[0004]

[Problems to be solved by the device]

 However, the fluorescent display tube configured as described above has the following problems. The insulating layer 5 is formed by a printing method, and there is no problem if the film thickness is as thick as about 20 μm or more. However, when the insulating layer 5 is manufactured by the photolithography method, the film thickness is as thin as 8 to 12 μm. Therefore, pinholes are likely to occur. The generation of the pinholes facilitates electrical contact between the phosphor screen 6 formed on the insulating layer 5 and the lower wiring pattern 2. In other words, the fluorescent screen 6 normally has conductivity, and when the fluorescent display tube is driven, if the wiring pattern 2 passes below the fluorescent screen 6, the fluorescent screen 6 will end up at the end of the fluorescent screen 6 due to the energized state. Brightness spots are more likely to occur and display quality is degraded.

The reason why the insulating layer 5 is made thin is that the through hole 4 formed in the insulating layer 5 has a diameter of 200 to 300 μm and a depth of 20 μm. However, if the insulating layer 5 is made thick, the phosphor coating for forming the phosphor screen 6 does not reach the deep part of the through hole 4, and the anode coating 3 does not come into contact with the phosphor coating. In some cases, this is to prevent defective emission of the fluorescent surface 6. That is, the thin insulating layer 5 is formed in order to form a fine phosphor pattern.

Therefore, the present invention has been made in order to solve the above-mentioned conventional problems, and its purpose is to provide a luminance unevenness due to conduction due to a pinhole between a phosphor screen and a wiring pattern passing thereunder. An object of the present invention is to provide a fluorescent display tube capable of reliably preventing the occurrence of the above and improving the display quality.

[0007]

[Means for Solving the Problems]

 In order to achieve such an object, the fluorescent display according to the present invention includes a first wiring pattern having an anode pad deposited on an insulating substrate and a first wiring pattern deposited on the insulating substrate. A second wiring pattern having a potential different from that of the wiring pattern, an insulating layer deposited on the surface of the insulating substrate except the anode pad, and a phosphor layer deposited on the anode pad. However, the second wiring pattern is arranged in a position where it does not intersect the phosphor layer.

[0008]

[Mode for Carrying Out the Invention]

 Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view illustrating one embodiment of a fluorescent display tube according to the present invention based on a manufacturing method, and the same parts as those in FIG. 3 are denoted by the same reference numerals. In FIG. 1, first, a thin film of Al having a thickness of about 0.8 to 1.3 μm is formed on a glass substrate 1 by a sputtering method. Next, the Al thin film is etched by a photolithography method using a photomask (not shown) on which a wiring pattern portion and an anode pad portion having predetermined dimensions are formed, and the wiring pattern 2, the anode pad 3 and this anode pad 3 are formed in the same manner. Adjacent wiring patterns 2'having no potential are simultaneously formed.

The wiring patterns 2 and 2 ′ thus formed have a line width of 30 μm and a pitch of 60 μm, and the anode pads 3 are 200 to 300 μm square. In this case, as shown in the plan view of the main part of FIG. 2, the anode pad 3 and the wiring pattern 2'having a different potential difference adjacent to each other are formed with a certain space therebetween, and the upper layer of this vacant portion is formed. The phosphor layer 6 described below is formed so that the end portion of the phosphor layer 6 is located. In FIG. 2, reference numeral 3'denotes an adjacent anode pad having a different potential difference, and 6'denotes a phosphor layer thereof.

Next, an insulating paste for thick film printing, which is a mixture of low-melting frit glass (components PbO, B ₂ O _3, etc.) powder, a photosensitive liquid, and a pigment (components are mainly metal oxides), is made into glass. After printing on the entire surface of the substrate 1 and drying, the upper surface of the glass substrate 1 is exposed using a photomask having an opening pattern on the anode pad 3, and development is performed to expose the anode pad 3.

Here, when the photosensitive liquid material in the above-mentioned insulating paste is a negative type photosensitive material, the exposed portion becomes insoluble in the developing solution, and the unexposed portion melts in the developing solution to spread on the anode pad 3. An insulating layer 5 having a through hole 4 is formed. On the other hand, when the photosensitive liquid material is a positive type, the exposed portion is melted in the developing solution, and the insulating layer 5 having the through hole 4 is similarly formed on the anode pad 3. The insulating layer 5 thus formed has a structure that covers most of the glass substrate 1 and the wiring patterns 2 and 2 ′ with a dark black color having a thickness of about 10 to 15 μm.

Next, when the glass substrate 1 on which the insulating layer 5 is formed is baked in air at about 560 ° C. for about 30 minutes to 1 hour, the photosensitive liquid material in the insulating layer 5 is thermally decomposed, It is volatilized and dissipated in the air, and at the same time, the low melting point glass is melted and fixed to form a mechanically strong insulating layer 5. At this time, the thickness of the insulating layer 5 is about 8 to 12 μm, and a pattern faithful to the photomask is formed.

Next, the phosphor layer 6 is directly formed on most of the anode pad 3 to complete the production of the anode substrate. There are various methods for forming the phosphor layer 6, which differ depending on the emission color, the composition of the phosphor matrix or the color classification (which part of the substrate is used for which color). The three methods of electrodeposition, photolithography or printing described can be used. As another method, a deposition method, a pre-exposure method, an electrostatic coating method, a slurry method, or the like may be used.

According to this structure, since the adjacent wiring patterns 2 ′ are formed below the phosphor layer 6 so as not to intersect with each other, the phosphor layer due to the occurrence of pinholes in the insulating layer 5 is formed. No contact between the wiring pattern 6 and the adjacent wiring pattern 2'is made, and when the fluorescent display tube is driven, no brightness unevenness is generated at the end portion of the phosphor layer 6 due to the conduction state.

[0015]

[Effect of device]

 As described above, according to the present invention, since the wiring pattern connected to the phosphor layer and the adjacent wiring pattern having a different potential difference are arranged so as not to intersect each other, the wiring pattern is adjacent to the phosphor layer. Continuity failure due to pinholes in the insulating layer between the wiring pattern and the wiring pattern can be avoided, and it is possible to reliably prevent the occurrence of luminance unevenness at the end of the phosphor layer due to the conduction state when the fluorescent display tube is driven. And a fluorescent display tube of high quality and high reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an anode substrate illustrating a structure of a fluorescent display tube according to an embodiment of the present invention.

FIG. 2 is a plan view of relevant parts of the anode substrate shown in FIG.

FIG. 3 is a cross-sectional view of an anode substrate for explaining the configuration of a conventional fluorescent display tube.

[Explanation of symbols]

1 ... Glass substrate, 2, 2 '... Wiring pattern, 3 ... Anode pad, 4 ... Through hole, 5 ... Insulating layer, 6 ... Phosphor layer.

Claims (1)

[Scope of utility model registration request] 1. A first wiring pattern having an anode pad deposited on an insulating substrate, and a second wiring pattern deposited on the insulating substrate and having a potential difference different from that of the first wiring pattern. A wiring pattern, an insulating layer deposited on a surface of the insulating substrate excluding the anode pad, and a phosphor layer deposited on the anode pad, the second wiring The fluorescent display tube, wherein the pattern is arranged at a position not intersecting with the phosphor layer.