Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Making named article
Reexamination Certificate
2002-07-09
2004-10-12
McPherson, John A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Making named article
C430S319000, C430S325000
Reexamination Certificate
active
06803174
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to methods for manufacturing a reflection type liquid crystal display (LCD) and a reflection and transmission composite type LCD, and more particularly, to methods for forming a photosensitive insulating film pattern and a reflection electrode each having an uneven upper surface, and a method for manufacturing a LCD having the reflection electrode using the same.
2. Description of the Related Art
In an information-oriented society these days, the role of an electronic display is becoming more important. All kinds of electronic displays are widely used in various industrial fields. As techniques of the electronic display field are continuously developed, various electronic displays having new functions are provided corresponding to diverse requirements of the information-oriented society.
Generally, an electronic display is an apparatus for visually transmitting information to a person. That is, an electronic display can be defined as an electronic apparatus, which converts an electrical information signal output from various electronic equipments into a visually recognizable optical information signal. Also, it may be defined as an electronic apparatus serving as a bridge for connecting the person and the electronic equipment.
These electronic displays are classified into an emissive display, in which the optical information signal is displayed by a light-emitting method, and a non-emissive display, in which the signal is displayed by an optical modulation method such as light-reflecting, dispersing and interference phenomena, etc. As the emissive display is called an active display, a CRT (cathode ray tube), a PDP (plasma display panel), an LED (light emitting diode) and an ELD (electroluminescent display), etc. may also be mentioned. As the non-emissive display is called a passive display, an LCD, an EPID (electrophoretic image display), etc. may also be mentioned.
The CRT has been used in an image display device such as a television receiver and a computer monitor, etc., over the longest period of time. The CRT has the highest market share in an aspect of displaying quality and economical efficiency, but it also has many disadvantages such as a heavy weight, a large volume and high power consumption.
Meanwhile, as various kinds of electronic devices are small-sized and lighter in weight, along with the solidification and lower voltage and lower driving power of the electronic devices due to rapid advancement of semiconductor technologies, there is requested a flat panel type display having slimmer and lighter properties as well as lower driving voltage and lower power consumption characteristics according to the novel environment.
Among variously developed flat panel type displays, the LCD is much slimmer and lighter than any other displays and it has lower driving voltage and lower power consumption. Also, the LCD has the displaying quality similar to that of the CRT. Therefore, the LCD is widely used in various electronic devices. Further, since the LCD can be easily manufactured, its application is becoming gradually wider.
The LCD is classified into a transmission type LCD, which displays an image using an external light source and a reflection type LCD, which displays the image using ambient lights instead of the external light source.
The reflection type LCD has an advantage in that it consumes less power and shows an excellent display outdoors as compared with the projection type LCD. Further, the reflection type LCD is thin and light because an additional light source such as a backlight apparatus is not necessary.
However, the current reflection type LCD has a dark screen and fails to show high definition and multicolor images. Therefore, the reflection type LCDs are restrictively employed for a product that requires a simple pattern display, such as numbers or simple characters.
To use a reflection type LCD for various electronic displays, a high definition and a multicolor display together with an enhanced reflection luminance are necessary. In addition, proper brightness, rapid response speed and enhancement of contrast are necessary.
In current reflection type LCDs, two technologies are combined for an enhancement of the brightness. One is enhancing the reflection efficiency of the reflection electrode, and the other is achieving an ultra high aperture ratio. Naofumi Kimura discloses a method of enhancing the reflection efficiency by forming bumps to a reflection electrode in U.S. Pat. No. 5,610,741, issued Mar. 11, 1997, entitled “Reflection Type Liquid Crystal Display Device with Bumps on the Reflector.”
FIG. 1
is a partial plan view of the reflection type LCD device provided in the above U.S. Patent, and
FIG. 2
is a sectional view of the reflection type LCD device of FIG.
1
.
Referring to
FIGS. 1 and 2
, the reflection type LCD device is comprised of a first substrate
10
, a second substrate
15
facing the first substrate
10
and a liquid crystal layer
20
interposed between the first and second substrates
10
and
15
.
The first substrate
10
includes a first insulating substrate
30
on which a plurality of gate bus wirings
25
is formed. Gate electrodes
35
branch off from the gate bus wirings
25
. Additionally, a plurality of source bus wirings
40
are provided so as to be orthogonal with and maintain the insulation from the plurality of gate bus wirings
25
due to an insulating layer between the source bus wirings
40
and the gate bus wirings
25
. Source electrodes
45
branch off from the source bus wirings
40
.
Reflection electrodes
50
are formed between the first substrate
10
and the liquid crystal layer
20
and are disposed in a plurality of rectangular regions formed by crossing the plurality of gate bus wirings
25
and the plurality of source bus wirings
40
.
The reflection electrode
50
is connected with a thin film transistor (TFT) device
55
formed on the first substrate
10
, the TFT device
55
serving as a switching device with the gate bus wiring
25
and the source bus wiring
40
.
A plurality of dents
70
and
71
are provided on the surface of the reflection electrode
50
, whereby the surface is made bumpy. The plurality of dents
70
and
71
are irregularly arranged on the entire surface as depicted in FIG.
1
. The reflection electrode
60
and a drain electrode of the TFT device
55
are connected to each other through a contact hole
65
.
The gate bus wiring
25
and the gate electrode
35
are formed on the first insulating substrate
30
made of, for example, glass by depositing tantalum (Ta) film using a sputtering method and patterning the deposited Ta film using an etching or a photolithography process.
Next, the gate insulating film
75
is formed to cover the gate bus wiring
25
and the gate electrode
35
. The gate insulating film
75
is made, for example, by forming a 4000 Å thick SiNx film by a plasma CVD (Chemical Vapor Deposition) method.
Referring to
FIG. 2
, a semiconductor layer
80
of amorphous silicon (a-Si) is formed on the gate insulating layer
75
on the gate electrode
35
. Contact layers
85
and
90
of n+ type impurities-doped a-Si layer are formed on the semiconductor layer
80
.
Subsequently, molybdenum (Mo) film is formed on the first insulating substrate
30
to cover those members formed in the above-mentioned manner and then the Mo film is patterned to form a source bus wiring
40
, a source electrode
45
and a drain electrode
60
. In such a manner, a TFT device
55
including the gate electrode
35
, the semiconductor layer
80
, the contact layers
85
and
90
, the source electrode
65
and the drain electrode
60
is completed.
On the entire surface of the insulating substrate
30
in which the TFT element
55
was formed, an organic insulating film
95
and a reflection electrode
50
each having a bumpy surface are sequentially formed.
FIGS. 3A and 3B
are sectional views showing the steps of a method for forming bumps in the device shown in FIG.
2
.
Referring to
F
Jang Yong-Kyu
Kim Jae-Hyun
McGuireWoods LLP
McPherson John A.
Samsung Electronics Co,. Ltd.
LandOfFree
METHODS FOR FORMING A PHOTOSENSITIVE INSULATING FILM PATTERN... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with METHODS FOR FORMING A PHOTOSENSITIVE INSULATING FILM PATTERN..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and METHODS FOR FORMING A PHOTOSENSITIVE INSULATING FILM PATTERN... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3279210