Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2001-03-05
2003-06-03
Kim, Robert H. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S106000, C349S110000, C349S187000, C324S701000
Reexamination Certificate
active
06573960
ABSTRACT:
BACKGROUND OF THE INVENTION
Technical Field of the Invention
The present invention relates to a liquid crystal device, its manufacturing method, and an electronic apparatus. More specifically, the invention relates to a liquid crystal device having a color filter layer, its manufacturing method, and an electronic apparatus.
DISCUSSION
Liquid crystal display devices are displays in which a liquid crystal is interposed between a pair of substrates that are opposed to each other, and perform display by modulating light that passes through the liquid crystal in accordance with the orientation of the liquid crystal. The reflection type and the transmission type are known as display modes of liquid crystal display devices.
FIG. 12
shows a reflection display type passive matrix liquid crystal device
500
as an example of those kinds of liquid crystal devices. A liquid crystal layer
160
is interposed between a pair of substrates
120
and
140
that are opposed to each other, and image display or the like is performed by modulating light that passes through the liquid crystal in accordance with the orientation of the liquid crystal layer
160
. Transparent electrodes
240
a
made of indium tin oxide (hereinafter referred to as “ITO”) or the like are provided on a surface, opposed to the substrate
140
, of the substrate
120
. A light-reflective metal film (reflection film)
300
is provided on a surface, opposed to the substrate
120
, of the substrate
140
, and a color filter layer consisting of colored layers
200
a
,
200
b
, and
200
c
of blue, green, and red, respectively, and transparent electrodes
240
b
are provided on the metal film
300
. Pixels are formed at regions where the transparent electrodes
240
a
and
240
b
cross each other, and the colored layers are provided so as to correspond to the respective pixels. A light shield layer
240
to serve as a black matrix is formed between the colored layers. A protective layer
220
is formed on the colored layers and the light shield layer
240
, and the transparent electrodes
240
b
are formed on the protective layer
220
.
In the liquid crystal device
500
, incident light coming from the substrate
120
side is converted by the colored layers
200
a
,
200
b
, and
200
c
into light beams P
1
, P
2
, and P
3
that are colored in blue, green, and red, respectively, which are reflected by the reflection film
300
and outputted from the substrate
140
side. Combined light P of the light beams P
1
, P
2
, and P
3
is recognized as a color image.
Since reflection display type liquid crystal devices of the above kind can perform display by using ambient light such as light of a fluorescent lamp, natural light, or the like without the need for incorporating a light source such as a backlight, they are advantageous in terms of power consumption and hence are widely used in portable display apparatus, etc.
Incidentally, to keep proper display color characteristics of a color image, it is necessary to manage the blue, green, and red color characteristics of the color filter layer individually. Since usually the color filter layer is produced by a dyeing method or a pigment dispersion method in which a resin or the like is applied by spin coating, the thickness subtly varies from one substrate produced to another. As a result, the color characteristics of the color filter layer slightly vary from one substrate to another. For this reason, in managing the color filter layer, it is necessary to measure the color characteristics on a substrate-by-substrate basis.
However, reflection type liquid crystal display devices of the above kind have a problem that if measurement light is made incident from the back surface (outside) of the color filter layer side substrate according to the ordinary color characteristic evaluation method, the measurement light does not reach the color filter layer because it is reflected by the reflection film. Further, if measurement light is made incident from the front surface (color filter layer side) of the substrate, the measurement light that has passed through the color filter layer is reflected by the reflection film and passes through the color filter layer again, that is, reflection light is measured. This results in another problem that the color characteristics of the color filter layer cannot be evaluated with high accuracy. The same is true of a case of measuring the optical density (OD value) that represents a light shield state of the light shield layer. The OD value is given by
OD
=−log
10
(
I/I
0
) (1)
where I
0
is the intensity of input light to the light shield layer and I is the intensity of transmission light. The light shield performance is better when this value is larger.
An object of the present invention is to provide a liquid crystal device that is improved in color characteristics and light shield characteristic, its manufacturing method, and an electronic apparatus by solving the above problems in liquid crystal devices and thereby performing, with high accuracy, evaluation of the color characteristics of the individual colored layers of the color filter layer and measurement of the optical density of the light shield layer.
SUMMARY OF THE INVENTION
To attain the above object, the invention provides a liquid crystal device in which a liquid crystal layer is interposed between a color filter substrate and a counter substrate that is opposed to the color filter substrate, characterized in that the color filter substrate has, on a surface opposed to the counter substrate, a reflection film and a color filter layer including blue, green, and red colored layers and a light shield layer that is provided between the colored layers; that colored layers for color characteristic evaluation and a light shield layer for optical density measurement are provided outside an effective pixel area of the color filter substrate, the colored layers for color characteristic evaluation being provided at least one for each color; and that each region where the colored layers for color characteristic evaluation and the light shield layer for optical density measurement is formed has a portion where the reflection film is not provided.
With this configuration, since light passes through the portions where the reflection film is not formed, color characteristic evaluation of the colored layers and optical density measurement of the light shield layer can be performed with high accuracy by measuring a spectrum of transmitted light.
Since the color filter layer for color characteristic evaluation and the light shield layer for optical density measurement are provided outside the effective pixel area, the color characteristics, etc. can be evaluated at a position close to the color filter layer and the light shield layer in the actual image display area. Therefore, the measurement accuracy is further increased and miniaturization of liquid crystal devices can be attained.
The invention provides a liquid crystal device in which a liquid crystal layer is interposed between a color filter substrate and a counter substrate that is opposed to the color filter substrate, characterized in that the color filter substrate has, on a surface opposed to the counter substrate, a reflection film and a color filter layer including blue, green, and red colored layers and a light shield layer that is provided between the colored layers; that colored layers for color characteristic evaluation and a light shield layer for optical density measurement are provided outside an effective pixel area of the color filter substrate, the colored layers for color characteristic evaluation being provided at least one for each color; and that each region where each of the colored layers for color characteristic evaluation and the light shield layer for optical density measurement is formed has part of the reflection film formed with a window.
With this configuration, since light passes through the windows, color characteristic evaluation of the colored layers and optical density measurement of the light s
Kobayashi Masaki
Takizawa Keiji
Tanaka Chihiro
Yamaguchi Yoshio
Harness & Dickey & Pierce P.L.C.
Kim Robert H.
Schechter Andrew
Seiko Epson Corporation
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