Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2000-10-26
2003-09-16
Ton, Toan (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S122000, C349S158000, C349S187000
Reexamination Certificate
active
06621542
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to electro-optic panels having marks, such as alignment marks and marks for process control, and to manufacturing methods therefor. In addition, the present invention relates to electro-optic devices comprising electro-optic panels. Furthermore, the present invention relates to electronic apparatuses comprising the electro-optic devices.
2. Description of the Related Art
Display devices have been widely used for mobile apparatuses and information display terminals at home, in offices and/or at worksites, in cars, and the like. In particular, liquid crystal display panels have features such as being thin and lightweight and using low voltage and having low power consumption. Recently, since the need for even lower power consumption has increased, the use of reflective liquid crystal display devices has increased. A reflective liquid crystal display device is a liquid crystal device provided with a reflective layer so as to utilize incident light thereon from the outside as a light source. The reflective liquid crystal device has a liquid crystal display panel.
Hereinafter, a liquid crystal display panel used for the reflective liquid crystal device will be described.
FIG. 16
is a schematic plan view showing a liquid crystal display panel.
A liquid crystal display panel
600
has a first substrate
610
and a second substrate
620
.
The first substrate
610
and the second substrate
620
oppose each other. At a predetermined side edge portion (lower side in
FIG. 16
) of the liquid crystal display panel
600
, the first substrate
610
is disposed so that an edge portion thereof protrudes toward the outside from an edge portion of the second substrate
620
. That is, the first substrate
610
has a portion (hereinafter referred to as a “protruding portion of the first substrate”)
612
at which the first substrate
610
does not overlap the second substrate
620
.
At a side edge portion (left side in
FIG. 16
) adjacent to the side edge portion of the liquid crystal display panel
600
described above, the second substrate
620
is disposed so that an edge portion thereof protrudes toward the outside from an edge portion of the first substrate
610
. That is, the second substrate
620
has a portion (hereinafter referred to as a “protruding portion of the second substrate”)
622
at which the second substrate
610
does not overlap the first substrate
610
.
At predetermined locations on the first protruding portion
612
and the second protruding portion
622
, alignment marks
670
are formed.
FIG. 17
is a schematic cross-sectional view of the part taken along the line B—B in FIG.
16
.
At the periphery between the first substrate
610
and the second substrate
620
, a sealing member
632
is formed. Since the sealing member
632
is formed, a predetermined gap (hereinafter referred to as a “cell gap”)
630
is maintained between the first substrate
610
and the second substrate
620
. In addition, in the cell gap
630
, liquid crystal is enclosed, whereby a liquid crystal layer
634
is formed.
The surface of the first substrate
610
opposing the second substrate
620
is formed to have an irregular surface
614
. The irregular surface
614
is so formed in order that light for display will be scattered so as to increase the viewing angle. In addition, on the irregular surface
614
, a reflective layer
640
is formed. The shape of the upper surface of the reflective layer
640
conforms to the irregular surface thereunder. On the reflective layer
640
, a layered structure [laminate] (not shown) composed of a transparent electrode, an alignment film, and the like is formed.
On the surface of the second substrate
620
opposite the first substrate
610
, a retardation film
684
and a polarizer
686
are formed. On the surface of the second substrate
620
opposing the first substrate
610
, a layered structure (not shown) composed of a transparent electrode, an alignment film, and the like is formed.
On the irregular surface
614
in the protruding portion
612
of the first substrate
610
, the alignment marks
670
are formed.
FIG. 18
is an enlarged schematic view of B in FIG.
17
.
As shown in
FIG. 18
, when the alignment marks
670
are formed on the irregular surface
614
, the upper surfaces
674
of the alignment marks
670
conforms to the shape of the irregular surface
614
. In the case in which the first substrate
610
and a flexible circuit board (not shown) are aligned with each other, when the upper surfaces
674
of the alignment marks
670
are irregular, problems may occur.
The alignment mentioned above is performed by detecting light emitted from a light source (not shown) by, for example, a CCD camera (not shown). The light source and the CCD camera are disposed at locations opposing the alignment marks
670
. In the case in which the upper surfaces
674
of the alignment masks
670
are irregular, when the alignment is performed, as shown in
FIG. 18
, the light is scattered at the upper surfaces
674
of the alignment marks
670
, and hence, the image detected by the CCD camera is blurred. consequently, the alignment marks
670
are difficult to be visually detected using the CCD camera. As a result, alignment is difficult to perform when the alignment marks
670
are formed as described above.
An object of the present invention is to provide an electro-optic panel in which visual detection of a mark can be performed properly [optically] and to provide a manufacturing method therefor.
Another aspect of the present invention is to provide an electro-optic device and an electronic apparatus, which include the electro-optic panel.
SUMMARY OF THE INVENTION
An electro-optic panel of the present invention comprises, a first substrate and a second substrate opposing each other, in which the first substrate has a protruding portion formed so that an edge portion thereof protrudes toward the outside from an edge portion of the second substrate, and in which a surface of the first substrate opposing the second substrate has an irregular surface, a planarized layer provided on the irregular surface in the protruding portion; and a mark provided on the planarized layer.
In this context, the mark is an alignment mark or a mark for process control.
According to the electro-optic panel of the present invention, the visual [or optical] detection of the mark can e performed properly.
Hereinafter, the reasons for this will be described. In the electro-optic panel of the present invention, the mark is formed on the planarized layer. Accordingly, at the upper surface of the mark, light scattering can be reduced. As a result, the visual detection of the mark can be performed properly. Consequently, according to the electro-optic panel of the present invention, compared to the case of an electro-optic panel in which the mark is formed on an irregular surface, for example, the alignment of the electro-optic panel with a flexible circuit board can be performed with high precision.
In addition, in the electro-optic panel of the present invention, the alignment mark is formed above the protruding portion. Accordingly, the electro-optic panel of the present invention is particularly useful, for example, when the alignment of a circuit board for connection (for example, a flexible circuit board) or a driver IC with the electro-optic panel is performed.
The electro-optic panel described above can be preferably used as a liquid crystal panel. In addition, the electro-optic panel can be more particularly used as a reflective liquid crystal panel and as a transflective liquid crystal panel.
The material for the planarized layer is not specifically limited; however, the material is preferably similar to that for the first substrate in terms of an optical characteristic. The optical characteristic mentioned above is refractive index. In addition, the similarity of the optical characteristic means that the values of the refractive indexes thereof are close to each
Harness & Dickey & Pierce P.L.C.
Schechter Andrew
Seiko Epson Corporation
Ton Toan
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