JP2001221629A - Method for inspecting shape of plastic body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape inspecting method, capable of simply and highly accurately inspecting the surface shape of a plastic body, even it is a plastic body with a fine surface shape such as a reflecting plate to be used for a reflecting-type liquid crystal display device, and to provide its substrate material. SOLUTION: A resin material is applied to a plastic body (substrate material 1) formed into a prescribed shape, hardened and is integrated under conditions which does not change the shape of the plastic body. Then the plastic body and hardened resin material 2 are cut to prepare a sample piece, and the cross- sectional shape of the plastic body is observed through the use of the sample piece.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting the shape of a molded product, and more particularly to an inspection method suitable for inspecting the surface shape of a reflector for a liquid crystal display device and its base material.

[Prior art]

Recently, a reflection plate having a fine cross section has been developed as a reflection plate used in a reflection type liquid crystal display device. This reflector is formed by forming a substrate 1 having a sawtooth cross section as shown in FIG. 4 using a synthetic resin such as a polycarbonate resin, and depositing a metal reflection film such as aluminum on the surface of the substrate 1. Manufactured. Since such reflectors require high precision in light reflection characteristics, high precision is required in the shape of the surface serving as the reflection surface. Specifically, the surface of the substrate 1 shown in FIG. 4 usually has a pitch (A) of 10 to 40 μm.
Has a very fine sawtooth shape with a height (B) of 3 to 50 μm, so that whether the pitch and height are within a predetermined allowable range, and whether the shape for each pitch appears correctly It is necessary to check whether or not.

The molding of the substrate 1 is usually performed by embossing the surface of a synthetic resin plate. In this case, the substrate 1
Depending on the manufacturing conditions, the surface shape of the substrate 1 may be deformed. Therefore, it is necessary to inspect the surface shape of the substrate 1 before vapor deposition of the metal reflection film. In addition, in the step of depositing the metal reflection film, since the surface of the base material may be deformed by heat during the deposition, it is necessary to inspect the surface shape of the reflection plate even after the deposition of the metal reflection film.

Inspection of a fine surface shape of a molded article or the like is generally performed by a method of observing a shape with a surface observation microscope (laser scan method) or a method of observing a cut surface with a scanning electron microscope. In the former case, the reflected light of the laser is used, so that it may be difficult to obtain the reflected light depending on the surface shape and correct measurement may not be performed. On the other hand, in the latter case, as a preliminary treatment, the molded body is thinly cut with a microtome or the like to prepare a sample piece, but it is very difficult to cut without losing the original shape because it is easily deformed at the time of cutting. Observing the obtained specimen with a scanning electron microscope,
It is difficult to observe the shape accurately.

[0005]

In order to solve the above-mentioned problems, a silicone resin is poured into the surface of the substrate 1 and cured, and then the cured silicone resin is peeled off to produce a so-called silicone replica. Then, it has been proposed to cut the replica and observe the surface shape with a surface observation microscope. However, such a method requires a great deal of time and cost for producing a replica, and also has a problem that the accuracy of inspection is inferior.

Accordingly, an object of the present invention is to provide an inspection method capable of easily and highly accurately inspecting a surface shape even of a molded article having a fine surface shape such as the base material. That is.

[0007]

According to the shape inspection method of the present invention for solving the above-mentioned problems, a resin material is applied to a molded article formed into a predetermined shape under conditions that do not change the shape of the molded article. After being cured and integrated, the molded body and the cured resin material are cut to form a sample piece, and the cross-sectional shape of the molded body is observed using the sample piece. Here, applying and curing the resin material under conditions that do not change the shape of the molded body means that the external force such as thermal deformation, shrinkage, or expansion does not substantially act on the molded body during application and curing of the resin material. Means that

As described above, in the present invention, since the resin material is applied to the surface of the molded body and cured, the surface shape of the molded body is fixed and protected by the cured resin material. Even if the body is cut, there is no possibility that the surface shape of the formed body is deformed, and accurate surface observation is possible.

In the inspection method of the present invention, it is preferable to coat the surface of the molded body with a metal thin film and then apply the resin material. Thereby, the interface between the molded article and the cured resin material becomes clear, and the shape observation of the molded article becomes easy. The inspection method of the present invention is particularly suitable for inspection of a reflection plate used for a reflection type liquid crystal display device and its base material.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. In this embodiment, the inspection method of the present invention is applied to inspection of a reflector used in a reflection type liquid crystal display device. FIG. 1 shows an inspection method according to this embodiment, and FIG. 1A shows a substrate 1 made of a polycarbonate resin.
(Mold). The cross section of the surface 1a of the base material 1 is formed in a sawtooth shape by embossing as described above.

In order to carry out the inspection according to the method of the present invention, first, the substrate 1 is bonded and fixed to the surface of a suitable reinforcing material 3 in order to prevent the substrate 1 from bending during cutting. Examples of the reinforcing material 3 include various hard materials, for example, an acrylic resin plate. Further, as an adhesive for bonding to the reinforcing material 3, for example, a room temperature curing type epoxy resin adhesive or the like can be used.

After bonding the substrate 1 to the reinforcing member 3, a resin material is applied to the surface 1a of the substrate 1. As the resin material, a resin material that is excellent in adhesiveness to the base material 1 and does not change the shape of the base material 1 during application or curing is used. As such a resin material, a non-solvent type material having room-temperature curability is preferable, and when a solvent is contained, the base material 1 may swell. In the case of a heat-curable resin, the substrate 1 may be thermally deformed during curing. Further, those having excellent dimensional stability that do not cause curing shrinkage or the like during curing are preferable. As such a resin material, for example, the same cold-setting epoxy resin adhesive used for bonding to the reinforcing material 3 described above can be used.

The method and amount of application of the resin material are not particularly limited, and the resin material may be applied to an arbitrary thickness by a method such as brushing, pouring, dipping, or the like. After the application, the resin material is cured to obtain a substrate 1 having a cured resin material 2 laminated and adhered to the surface, as shown in FIG. Then, using a cutting tool such as a glass knife and a diamond knife with a microtome,
The base material 1 is sent out together with the cured resin material 2 at a thickness of 0.5 to 5 μm and cut and processed to make the surface smooth and used as a sample. Then, the cross-sectional shape of the sample is observed to check whether the surface shape and dimensions are correctly formed.

The observation can be performed by, for example, a field emission scanning electron microscope (hereinafter referred to as FE-SEM), a thermal electron gun scanning electron microscope, or the like. Observation of substrate shape
In addition to the length and height per pitch (A and B shown in FIG. 4), the shape itself (for example, whether or not the cross-sectional shape per pitch is exactly an isosceles triangle) is also performed. A pass / fail judgment is made based on the result.

According to this embodiment, the back surface of the base material 1 is reinforced by the reinforcing material 3, and the surface shape is fixed and protected by the cured resin material 2 formed by applying and curing a resin material. The substrate 1 is prevented from bending or deforming in the cutting direction or the like. For this reason, cutting can be performed while maintaining the formed shape, and inspection accuracy is improved. In addition, the inspection results serve as a basis for correctly determining whether or not manufacturing such as molding has been appropriately performed, and can greatly contribute to improving the performance of the reflection plate and reducing quality defects.

According to a preferred embodiment of the present invention, FIG.
As shown in (1), a gold (Au) vapor-deposited film 4 (metal thin film) is provided on the surface of a substrate 1, and a resin material is applied and cured on the surface of the Au vapor-deposited film 4 to form a cured resin material 2. By interposing the Au vapor-deposited film 4 between the base material 1 and the cured resin material 2 as described above, the interface between the two becomes clear, the shape observation of the base material 1 is further facilitated, and the inspection accuracy is improved. There is an advantage of doing so.

The Au deposited film 4 can be formed by, for example, a vacuum deposition method, an ion sputtering method or the like.
In order to prevent the substrate 1 from being deformed during the formation of the Au vapor-deposited film 4, the thickness of the Au vapor-deposited film 4 is preferably as thin as possible, and is usually about 20 to 200 °.

After confirming by inspection that the base material 1 is formed in a predetermined shape in this way, as shown in FIG. 3, a metal reflection film 5 is formed on the surface of the base material 1 and a reflection plate 6 is formed.
Get. As the metal reflection film 5, an aluminum evaporation film, a gold evaporation film, a silver evaporation film, or the like is usually used. These deposited films are formed by, for example, a vacuum deposition method, an ion sputtering method, or the like. Further, since the thickness of the metal reflection film 5 is relatively large, usually about 200 to 1000 degrees, the base material 1 may be deformed by heat or the like and may be damaged when the metal reflection film is formed. For this reason, it is necessary to inspect whether or not the shape of the substrate 1 is abnormal due to the formation of the metal reflection film.

Therefore, in the same manner as described above, the condition for not changing the shape of the base material 1 is provided on the surface of the reflecting plate 6 in which the metal reflecting film 5 is formed on the surface of the base material 1 formed of a molded body having a predetermined shape. After applying and curing the resin material below to integrate, the reflector plate 6 and the cured resin material 2 are cut to form a sample, and the shape of the reflector 6 is observed using the sample. Thereby, it is possible to reliably inspect whether or not the base material 1 has been deformed by heat or the like during the formation of the metal reflection film 5 or not. It can be set to an appropriate one.

Although the above embodiment relates to a method for inspecting the shape of a reflection plate for a liquid crystal display device and its base material, the present invention can be similarly applied to other molded products requiring a shape inspection. is there.

[0021]

The inspection method of the present invention will be described in detail below with reference to examples and comparative examples.

Example 1 A back surface of a base material obtained by embossing the surface of a polycarbonate resin molded plate was used as a reinforcing material (polymethyl methacrylate rod) and a quick-curing epoxy resin adhesive ("Araldite Rapid" manufactured by Ciba Geigy). )) At room temperature. Next, the same epoxy resin adhesive was applied to the surface of the substrate with a spatula made of plastic and cured at room temperature.
Next, the base material was sent out with a microtome at a thickness of 1 μm and cut to obtain a sample with a smooth cut surface. Dotite (conductive paint: manufactured by Fujikura Kasei Co., Ltd.) is applied to the reinforcing material on the cut surface of the sample and the side surface of the sample, air-dried, and carbon is vapor-deposited to impart conductivity.
E-SEM (Hitachi: Model S-4500, 5 kV, 10 μ
A, WD (distance between objective lenses) = 15, excitation intensity of condenser lens 5, diaphragm 3). As a result, the base material was cut without impairing the cross-sectional shape, which made it possible to accurately observe and evaluate the cross-sectional shape of the base material.

Example 2 Gold (Au) was applied by ion sputtering to the surface of a substrate whose back surface was the same as that used in Example 1 and was reinforced with epoxy resin.
Was formed in the same manner as in Example 1 except that a Au vapor deposition film having a thickness of 100 ° was formed by vapor deposition for 50 seconds. As a result, by interposing the Au vapor-deposited film between the cured resin material and the base material, their interface becomes clear,
Inspection of the shape of the substrate has become more accurate and easier.

Example 3 Aluminum was vapor-deposited on the surface of a substrate to form a 600-mm-thick aluminum vapor-deposited film, and then the same epoxy resin adhesive as in Example 1 was applied. The cross-sectional shape was observed. As a result, the reflector was cut without impairing the cross-sectional shape, and therefore, it became possible to accurately observe and evaluate the cross-sectional shape of the reflector.

Comparative Example 1 A base material obtained by embossing the surface of a polycarbonate resin molded plate was cut to a thickness of 1 μm by a microtome to obtain a sample. This sample was affixed on a double-sided adhesive tape with the cut surface facing up, and fixed to a sample table. An Ag paste was applied to the substrate surface at the end surface of the sample, air-dried, and Pt-
Pd deposition was performed for 50 seconds. Then, the cross-sectional shape of the sample was observed by FE-SEM under the same conditions as in Examples 1 to 3.

Comparative Example 2 A 600 mm thick aluminum vapor-deposited film was formed on the surface of a substrate obtained by embossing the surface of a polycarbonate resin molded plate to produce a reflector. This reflector was cut with a microtome at a thickness of 1 μm to obtain a sample. This sample was stuck on a double-sided adhesive tape with the cut surface facing up, and fixed to a sample table. A around the substrate surface of the end surface of this sample
g paste was applied, air-dried, and Pt-Pd deposition was performed for 50 seconds. Next, the cross-sectional shape of the sample was observed by FE-SEM under the same conditions as in Examples 1 to 3. As a result of the observation, in Comparative Examples 1 and 2, the surface shapes of the base material and the reflecting plate were deformed in the cutting direction, and an accurate cross-sectional shape could not be observed.

[0027]

According to the present invention, it is possible to easily and accurately inspect the surface shape (cross-sectional shape) of a molded product having a fine surface shape. This has the effect of greatly contributing to the improvement of product quality and the reduction of defective products.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a preferred embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating an example of a reflection plate to be inspected in the present invention.

FIG. 4 is a perspective view including a partially enlarged view of a base material used for a reflection plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base material 2 Cured resin material 3 Reinforcement material 4 Au vapor deposition film (metal thin film) 5 Aluminum vapor deposition film (metal reflection film) 6 Reflector

Claims (3)

[Claims] 1. A molded article formed into a predetermined shape is coated with a resin material under conditions that do not change the shape of the molded article, cured and integrated, and the molded article and the cured resin material are cut to obtain a sample. A method for inspecting the shape of a molded body, comprising: preparing a piece; and observing a cross-sectional shape of the molded body using the sample piece. 2. The shape inspection method according to claim 1, wherein the resin material is applied after covering the surface of the molded body with a metal thin film. 3. A resin material is applied and cured on a surface of a reflector formed by forming a metal reflective film on a surface of a substrate formed in a predetermined shape under conditions that do not change the shape of the substrate. A method for inspecting the surface shape of a reflector, comprising cutting a reflector and a cured resin material to form a sample piece, and observing a cross-sectional shape of the reflector using the sample piece.