Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2002-12-09
2004-07-20
Kim, Robert H. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S114000
Reexamination Certificate
active
06765637
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a translucent reflection type electro-optic device, an electronic instrument therewith, and a method of fabricating a translucent reflection type electro-optic device. In particular, the present invention relates to a pixel configuration of a translucent reflection type electro-optic device.
2. Description of Related Art
Electro-optic devices, such as liquid crystal devices, are used as direct-viewing display devices of various instruments. Among the electro-optic devices, for instance, in an active matrix type liquid crystal device that uses a thin film transistor (TFT) as a pixel switching non-linear element, as shown in
FIGS. 16 and 17
, of a TFT array substrate
10
and an opposite substrate
20
that interpose a liquid crystal
50
as an electro-optic material, on the TFT array substrate
10
, a pixel switching TFT
30
and a pixel electrode
9
a
that is made of a transparent conductive film such as an ITO film electrically connected to the TFT
30
can be formed.
Furthermore, of the liquid crystal devices in a reflective type, in order to reflect an ambient light incident from a side of the opposite substrate
20
toward the opposite substrate
20
, a light reflection film
8
a
is formed on a bottom layer side of the transparent pixel electrode
9
a
. As shown with an arrow mark LA in
FIGS. 17 and 18
, the light that enters from the opposite substrate
20
side is reflected by the TFT array substrate
10
side, and a light that exits from the opposite substrate
20
side displays an image (reflection mode).
However, in the reflective type liquid crystal device, when directionality of the light reflected from the light reflection film
8
a
is strong, remarkable dependency on an angle of field, such as brightness, is different depending on an angle of viewing an image is caused. Accordingly, at the fabrication of a liquid crystal device, on a surface of an interlayer insulating film
4
or of a surface protection film (not shown) formed thereon, a photosensitive resin, such as acrylic resin, is coated in a thickness of 800 to 1500 nm. Thereafter, by use of photolithography of a bottom layer side of the light reflection film
8
a
in a region that overlaps with the light reflection film
8
a
in plane, a convexity and concavity formation layer
13
a
made of the photosensitive resin is selectively left with a predetermined pattern. Thereby, a surface of the light reflection film
8
a
is endowed with a concavity and convexity pattern
8
g
. In addition, since, in this state as it is, edges of the concavity and convexity formation layer
13
a
appear as it is in the concavity and convexity pattern
8
g
, another layer, a top layer insulating film
7
a
made of a photosensitive resin layer higher in fluidity, is coated and formed on a top layer of the concavity and convexity formation layer
13
a
, and thereby the surface of the light reflection film
8
a
is endowed with a concavity and convexity pattern
8
g
that is edgeless and formed in a smooth shape.
Furthermore, among the reflective liquid crystal devices in a translucent reflection type liquid crystal device that can display even in transmission mode, in the light reflection film
8
a
, in a region that overlaps with the pixel electrode
9
a
in plane, a light transmission window
8
d
is formed. So far, for instance, as shown in
FIG. 16
, one light transmission window
8
d
has been formed in rectangle for each pixel. In a region corresponding to the light transmission window
8
d
, the concavity and convexity formation layer
13
a
is either entirely formed or not at all formed, resulting in a flat surface.
In the translucent reflection type liquid crystal device thus configured, when a backlight device (not shown) is disposed on a side of the TFT array substrate
10
and a light exited from the backlight device is entered from the side of the TFT array substrate
10
, as shown with arrow marks LB
1
and LB
2
in
FIG. 18
, a light proceeding to the light reflection film
8
a
is intercepted with the light reflection film
8
a
and does not contribute in the display. By contrast, the light proceeding to the light transmission window
8
d
where the light reflection film
8
a
is not formed, as shown with an arrow mark LB
0
in
FIGS. 17 and 18
, transmits through the light transmission window
8
d
to the opposite substrate
20
side, resulting in contributing in the display (transmission mode).
SUMMARY OF THE INVENTION
However, in the existing translucent reflection type liquid crystal device, a display light amount in the reflection mode and that in the transmission mode are completely provided by areas of the light reflection film
8
a
and the light transmission window
8
d
. Accordingly, when the brightness of one display mode is heightened, that of the other display mode is sacrificed, resulting in a problem of difficulty in improving the brightness in both modes.
In view of the above problems, the present invention intends to provide a translucent reflection type electro-optic device that can increase a display light amount in both reflection mode and transmission mode, an electronic instrument therewith, and a method for fabricating a translucent reflection type electro-optic device.
In order to overcome the problems, the present invention can provide, a translucent reflection type electro-optic device including, on a substrate that holds an electro-optic material, a concavity and convexity formation layer made of a first light transmitting material formed in a predetermined pattern, a top layer insulating film made of a second light transmitting material formed on a top layer side of the concavity and convexity formation layer, a light reflection film formed on a top layer side of the top layer insulating film, and a light transmitting electrode formed on a top layer or a bottom layer of the light reflection film at a top layer side of the top layer insulating film. Further, a light transmission window can be partially formed in the light reflection film, and wherein the light transmission window is plurally formed at positions each of which overlaps with at least part of a plurality of convexities that forms the concavity and convexity formation layer, or with at least part of plurality of concavities. Additionally, each of the first light transmitting material and the second light transmitting material has a refractive index that endows an interface between the concavity and convexity formation layer and the top layer insulating film with a lens function that refracts a light entered from a back surface side of the substrate toward the light transmission window.
Furthermore, in the present invention, a method of fabricating a translucent reflection type electro-optic device that includes, on a substrate that holds an electro-optic material, a concavity and convexity formation layer made of a first light transmitting material formed in a predetermined pattern, a top layer insulating film made of a second light transmitting material formed on a top layer side of the concavity and convexity formation layer, a light reflection film formed on a top layer side of the top layer insulating film, and a light transmitting electrode formed on a top layer or a bottom layer of the light reflection film at a top layer side of the top layer insulating film. Further, a light transmission window is partially formed in the light reflection film. The method including plurally forming the light transmission window at positions each of which overlaps with at least part of a plurality of convexities that forms the concavity and convexity formation layer, or with at least part of a plurality of concavities. Further, the method can include using, as the first light transmitting material and the second light transmitting material, transparent materials having different refractive indices, and thereby endowing an interface between the concavity and convexity formation layer and the top layer insulating film with a lens function that refracts
Kim Richard H
Kim Robert H.
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