JP2003015111A - Manufacturing method for planar display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a planar display device wherein the thickness precision can be highly accurately controlled and no minute pit is generated. SOLUTION: A minute pit generating factor layer on at least one surface of insulation substrates 21 and 22 is removed. At least one insulation substrate 22 is made to be a thin plate having a desired substrate thickness by a chemical polishing method. The number of the minute pits on the surface of the insulation substrate 22 after polishing can be suppressed and the planar display device having high quality can be formed in a short time and at a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a flat panel display device with improved yield.

[0002]

2. Description of the Related Art Generally, a so-called flat display device in which a display element is formed by a liquid crystal or the like between a pair of insulating substrates is used for a high-definition projection display device or a display device which is required to be lightweight. In order to improve efficiency in manufacturing the flat panel display device, first, a large plate for multi-chambering is used as a pair of insulating substrates, and a plurality of display elements are formed between the pair of insulating substrates. After that, the insulating substrate is polished to a desired substrate thickness by either mechanical polishing or chemical polishing in order to reduce the weight.

Further, in the case of manufacturing a high-definition projection display device, at least one insulating substrate on the light incident side of the pair of insulating substrates forming the flat display device is polished. It is necessary to control the thickness accuracy with high accuracy. This is because the microlens substrate is attached after this. That is, in order to improve the light utilization efficiency of the microlens substrate, reduce the color mixture ratio, and control,
The thickness accuracy of the insulating substrate on the light incident side is ± 10 μm to 2
It is necessary to keep it at 0 μm, and thickness control is important.

In this case, it is difficult to control the thickness by mechanical polishing, and it is difficult to control the thickness accuracy with high accuracy.
In addition, since the polishing amount is several 100 μm, in the case of mechanical polishing, two-step polishing of rough cutting and mirror polishing is required, which takes a lot of time and cost, and it is difficult to maintain uniformity in the insulating substrate. .

On the other hand, in the case of chemical polishing, since a hydrofluoric acid type etching solution is used, the substrate thickness can be controlled uniformly. However, as shown in FIG. 5, if there are microcracks 12 or alteration on the surface of the insulating substrate 11, a circular pit or a minute pit having a diameter of about 20 μm to 100 μm is generated due to the progress of chemical polishing indicated by the arrow due to the influence. 13 is generated and is visually recognized to be defective.

[0006] Usually, microcracks 12 are apt to be generated or deteriorated on each surface of the insulating substrate 11 due to each process during manufacturing, and the generation of minute pits 13 is inevitable by chemical polishing.

[0007]

As described above, in the prior art, when polishing an insulating substrate, mechanical polishing makes it difficult to control the thickness accuracy with high precision, and requires two-step polishing of roughing and mirror polishing. It takes time and cost, and the uniformity is difficult. On the other hand, if chemical polishing is used,
Although it is possible to uniformly control the substrate thickness, there is a problem in that minute pits due to microcracks or the like may be generated and defective.

The present invention has been made in view of the above problems, and provides a method for manufacturing a flat display device capable of controlling the thickness accuracy with high accuracy and polishing an insulating substrate without producing minute pits. With the goal.

[0009]

The present invention is a method for manufacturing a flat display device, which comprises forming a display element between a pair of insulating substrates and then thinning at least one of the insulating substrates.
A removing step of removing the minute pit generation factor layer on the surface of the at least one insulating substrate, and a thinning step of thinning the at least one insulating substrate to a desired substrate thickness by a chemical polishing method after the removing step And
A thinning step of thinning the at least one insulating substrate to a desired substrate thickness by a chemical polishing method, and mechanically removing fine pits on the surface of the at least one insulating substrate after the thinning step And the like, the fine pits on the surface of the insulating substrate are suppressed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below.
The process of manufacturing the flat panel display device will be described with reference to the drawings.

FIG. 1 shows a flat panel display device formed in a large-panel, multi-cavity state. In FIG. 1, reference numerals 21 and 22 denote a pair of insulating substrates, for example, the insulating substrate 21 is a display element side substrate. It serves as an array substrate, and the insulating substrate 22 serves as a counter substrate of the light incident side substrate. The pair of insulating substrates 21 and 22 each have an area for a plurality of flat display devices, and a plurality of display elements are formed between the insulating substrates 21 and 22.
In addition, 23 is a sealing material for each display element, and in the separation step of the subsequent process, the large insulating substrates 21 and 22 are cut by the sealing material 23 for each display element to provide an individual flat display. Separated as a device. In addition, a pair of these insulating substrates 2
The periphery between 1 and 22 is sealed by a single or double substrate end sealing material 24 so that the liquid does not enter during the chemical polishing in the subsequent process.

As shown in FIG. 2, the surfaces of the pair of insulating substrates 21 and 22 formed in such a large plate and multi-chamfered state are subjected to mechanical polishing A to a mirror surface of 1 μm to 100 μm, preferably 3 μm to 30 μm. Grind. This mechanical polishing step is a removal step of removing the fine pit generation factor layer that causes microcracks or the like generated on the surfaces of the insulating substrates 21 and 22.

Next, the pair of insulating substrates 21 and 22 whose surfaces are mirror-polished are dipped in a hydrofluoric acid-based liquid bath, and then, as shown in FIG.
As shown in, chemical polishing B is performed and the original insulating substrate 21,
The thickness of 22, eg about 0.7 mm, is ground to the desired thickness, eg 0.38 mm. In the case of this chemical polishing B, it is necessary to select the insulating substrate 22 on the light incident side, which has a uniform thickness, by measurement, and to simultaneously process these in order to reduce the variation in thickness. Is.

The large plate and the pair of insulating substrates 21 and 22 in the multi-cavity state, which have undergone the process of FIG. 3, are cut by the sealing material 23 for each display element and separated into individual flat display devices.
Then, after a liquid crystal injecting step of injecting the liquid crystal 25 between the separated insulating substrates 21 and 22, and a sealing step, the microlens substrate 26 is assembled as shown in FIG. That is,
The microlens substrate 26 is aligned with a predetermined position on the insulating substrate 22 which is the light incident side substrate via the sealing material 27,
The sealing material 27 is fixed by being cured. After that, a low refractive index material 28 is injected between the microlens substrate 26 and the insulating substrate 22 to seal the microlens substrate 26 and the insulating substrate 22, thereby forming a projection type high-definition flat display device.

Here, in the state in which the large plate shown in FIG. 1 and the flat panel display having multiple surfaces are formed, a pair of insulating substrates 21,
The surface of 22 has a long manufacturing process until then, as shown in FIG.
As indicated by, the microcracks 12 are generated or the quality is changed. If this is subjected to chemical polishing B by dipping it into a hydrofluoric acid-based liquid tank as in the conventional case, the diameter is 20 μm due to the influence of microcracks 12 and surface alteration.
Or, a large number of minute pits 13 which are circular depressions of 100 μm are generated, resulting in a defect.

However, in this embodiment, as shown in FIG. 2, the surfaces of the pair of insulating substrates 21 and 22 are mirror-polished by mechanical polishing A, and micro pits are formed due to the microcracks 12 and altered portions. The factor layer is removed. Therefore, even if the chemical polishing B shown in FIG.
Almost no 13 occurs, so that it is possible to suppress the occurrence of defects and improve the yield.

Although mechanical polishing A is shown as the polishing method used in the step of removing the fine pit generation factor layer, it is not limited to this mechanical polishing A, and other polishing methods may be used.

Further, in the above embodiment, the mechanical polishing step was performed before the chemical polishing step. However, the polishing order is reversed, and the fine pit generation factor layer in which the fine pits 13 have already formed after chemical polishing is machined. The fine pits 13 themselves may be removed by polishing by polishing.

Further, in the above-described embodiment, the microlens substrate 26 shown in FIG. 4 is used as a flat display device to be manufactured.
The projection-type high-definition flat display device in which the
Other flat display devices can be similarly applied. For example, in order to reduce the weight of the flat panel display device, a pair of insulating substrates forming the direct-view flat panel display device may be thinned to reduce the weight, but the invention can also be applied to this case.

Generally, the small pits 13 such as circular depressions are
In the projection type flat display device, the light-incident side microlens substrate is used because it is long in the process and more likely to occur on the insulating substrate side where the display device is formed through many heat steps.
It is important to thin the insulating substrate 22 on the side where the 26 is bonded. On the other hand, it is not always necessary to thin the display element side insulating substrate 21 on the opposite side.

In this case, it is advisable to attach a protective film to the surface of the insulating substrate 21 on the display element side, which does not necessarily need to be thinned, in the step before the chemical polishing B, and peel the protective film after the chemical polishing B. If you do this,
Only the insulating substrate 22 on the light incident side, which is important to be thin, can be thinned by chemical polishing B.

[0022]

According to the present invention, even if a chemical polishing method is used for thinning an insulating substrate, it is possible to suppress the yield reduction due to the generation of minute pits, and it is possible to efficiently manufacture high quality.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a step of an embodiment of a method for manufacturing a flat panel display device of the present invention.

FIG. 2 is an explanatory diagram showing the next step of FIG. 1 above.

FIG. 3 is an explanatory view showing the next step of FIG. 2 above.

FIG. 4 is a sectional view showing the above flat display device.

FIG. 5 is an explanatory diagram showing a problem of the conventional example.

[Explanation of symbols]

21, 22 Insulating substrate

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H090 HD01 JB02 JC01 JC07 JC18                       JC19 JD01 JD14 JD15 LA12                 2K009 BB02 DD12 DD16 EE00                 5C094 AA10 AA15 AA42 AA43 AA46                       BA16 BA43 CA19 DA11 EA05                       EB02 ED01 FA02 GB10 JA08                 5G435 AA03 AA17 AA18 BB13 CC09                       DD04 EE12 GG02 KK05

Claims (4)

[Claims] 1. A method for manufacturing a flat display device, comprising forming a display element between a pair of insulating substrates and then thinning at least one of the insulating substrates. A flat panel display comprising: a removing step of removing the generation factor layer; and a thinning step of thinning the at least one insulating substrate to a desired substrate thickness by a chemical polishing method after the removing step. Device manufacturing method. 2. The method for manufacturing a flat panel display device according to claim 1, wherein the removal amount in the removal step of removing the fine pit generation factor layer is 1 μm to 100 μm. 3. A method of manufacturing a flat display device, comprising forming a display element between a pair of insulating substrates and then thinning at least one of the insulating substrates, wherein the at least one insulating substrate is chemically polished. And a thinning step of thinning the substrate to a desired substrate thickness by the step of: and a removing step of mechanically removing the minute pits on the surface of the at least one insulating substrate after the thinning step. Manufacturing method of display device. 4. A bonding step of bonding a protective film to an insulating substrate that is not thinned out of a pair of insulating substrates, and a peeling step of peeling the protective film after the thinning step. A method for manufacturing a flat panel display device according to claim 1.