Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making named article
Reexamination Certificate
2002-03-06
2004-07-06
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making named article
C430S002000, C430S302000, C430S321000, C430S330000, C264S001600, C264S002200, C264S102000
Reexamination Certificate
active
06759182
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates to manufacturing methods and apparatuses of an optical device and a reflection plate, that include a resin thin film having a micro-asperity pattern.
In this specification, “micro-asperity pattern” is a generic term of asperity shapes that develop one-dimensionally or two-dimensionally and are 0.1 &mgr;m to hundreds of micrometers in depth and arbitrary in width, length and shape.
“Reflection-type liquid crystal display device” is a generic term of devices in which a liquid crystal is sealed between a transparent counter substrate having a transparent electrode and an active matrix substrate having a reflection surface that is provided with a surface micro-asperity pattern.
Nowadays, liquid crystal display devices are increasingly applied to personal computers, TV receivers, word processors and video equipment, etc. On the other hand, to increase the functionality and reduce the size, power consumption, cost, etc. of such electronic equipment, reflection-type liquid crystal display devices that display an image by reflecting external light instead of using a backlight are being developed.
FIG. 17
shows an example of such reflection-type liquid crystal display devices. A reflection plate
1
used in the reflection-type liquid crystal display device is disposed under a counter substrate
28
that is composed of a transparent electrode facing a liquid crystal layer
27
, a color filter layer formed over the transparent electrode, a surface glass substrate disposed over the color filter layer, and other members. The reflection plate
1
is used to increase the viewing angle of the image display of the liquid crystal display device by diffuse-reflecting light coming from the counter substrate
28
.
The reflection plate used in this liquid crystal display device is formed by a melting method in which a photosensitive resin material is coated by spin coating or the like on the surface of a substrate made of glass or resin or the surface of a substrate in which TFT transistors, liquid crystal driving elements, etc. are formed on such a substrate and is patterned through photolithography to form an asperity pattern whose cross section has an almost rectangular shape. A smooth curved surface is then formed by surface tension through heat treatment.
An embossment, in which a micro-asperity pattern stamper is pressed against a resin thin film coated on a substrate, whereby a micro-asperity pattern is formed, is also known.
In the reflection-type liquid crystal display device, as shown in
FIG. 18
, a thin film transistor or a wiring contact
31
is disposed under a resin thin film
4
having a micro-asperity pattern
40
. Thus, a contact hole
37
penetrating the resin thin film
4
needs to be formed in order to obtain electrical contact.
In case where the micro-asperity pattern
40
is formed through the conventional melting method, the contact hole is made through photolithography using a photosensitive resin. This photolithography technique is suitable for forming the contact hole because it can make a through-hole without damaging a layer disposed therebelow as does wet etching using a strong acid or alkali solution or dry etching using reactive plasma does.
However, the melting method has problems that 1) three-dimensional degree of freedom that realizes an acute-angled or plane shape is low because the method makes an application of shape sagging, 2) a shape varies with a variation in melting conditions thus resulting in low processing accuracy, and 3) a large number of processing steps increases cycle time.
On the other hand, the embossment method has a high degree of three-dimensional freedom since a stamper transfers a micro-asperity pattern to the resin thin film. And this method can attain a micro-asperity pattern with high reproducibility. Furthermore, the embossment method can use any resin material if it is melted, leaving a wide range of choices.
However, the embossment method cannot maintain photosensitivity of a photosensitive resin thin film after a micro-asperity pattern of the resin thin film is formed when the photosensitive resin thin film is spin-coated on the surface of a substrate and heated to an appropriate temperature for press-shaping the resin thin film by using a stamper. This results in extinction of the photosensitivity.
SUMMARY OF INVENTION
The present invention provides a manufacturing method and apparatus of an optical device having a micro-asperity pattern, which are able to form various kinds of three-dimensional shapes with satisfactory processing accuracy and realize them as thin films.
The invention further provides manufacturing methods and apparatuses of an optical device and a reflection plate, each of which has liquid crystal driving elements or wiring contacts that are disposed under a micro-asperity pattern and has a conducting passage leading from a reflection plate placed on the top surface of the micro-asperity pattern to the liquid crystal driving elements or the wiring contacts.
The invention provides a manufacturing method of an optical comprising: coating a substrate
5
with a resin thin film
4
made of a photosensitive resin; controlling a temperature of the resin thin film
4
to a temperature that is lower than the photosensitivity extinction temperature so as to soften or melt the resin thin film
4
; and pressing a die having an inverted micro-asperity pattern against the resin thin film
4
in a state that the resin thin film
4
has been softened or melted, whereby a micro-asperity pattern is formed on a surface of the resin thin film
4
.
In this manufacturing method, the die has a member or portion having an inverted shape of that of at least a micro-asperity pattern to be formed on the surface of a resin thin film, and may be either a press male die or a roller-type die.
The optical device means an element whose surface is formed with at least a micro-asperity pattern to perform diffusion, focusing and reflection of light.
In this manufacturing method, the micro-asperity pattern surface of the die is pressed against the resin thin film, whereby a micro-asperity pattern is formed on the surface of the resin thin film. Therefore, the micro-asperity pattern that is left on the resin thin film is given an arbitrary three-dimensional shape. That is, a micro-asperity pattern can be obtained with a high degree of freedom and high reproducibility.
Since the temperature of the resin thin film formed on the substrate is controlled to a temperature that is lower than the photosensitivity extinction temperature of the resin thin film, it is possible to form a through-hole in the resin thin film or easily cut the shape of the resin thin film into an appropriate shape by photolithography, if required, after the temperature is controlled.
The micro-asperity pattern can be laid out regularly or arbitrarily by executing the die pressing step a number of times on the resin thin film.
In the invention, it is an effective measure to make adjustments by causing a relative movement between the substrate and the die so that a substrate-side alignment mark provided on the substrate coincides with a reference position on the die side. Using this technical measure, an error in the position of the substrate with respect to the die can be corrected by causing a relative movement between the substrate and the die so that the substrate-side alignment mark provided on the substrate coincides with the reference position on the die side. As a result, a micro-asperity pattern can be formed with high processing accuracy.
In the invention, it is also an effective measure to form a micro-asperity pattern on the surface of the resin thin film at an inert gas atmosphere or a low-pressure atmosphere having a pressure that is lower than atmospheric pressure. Using this technical measure, the air is exhausted in advance from a chamber that accommodates the manufacturing device for manufacturing an optical device. Therefore, oxygen and impurities contained in the air inside the chamber are exhausted and a micr
Aoyama Shigeru
Funamoto Akihiro
Ikeda Masaaki
Matsushita Motohiko
Chea Thorl
Omron Corporation
Osha & May L.L.P.
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