Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2001-07-06
2003-12-02
Kim, Robert H. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S113000, C349S122000, C349S160000
Reexamination Certificate
active
06657687
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a liquid crystal display, a manufacturing method thereof, and an electronic appliance.
2. Description of the Related Art
Hitherto, so-called transflective liquid crystal displays have been used, which can, as required, switch between the reflective display mode in which the external light including natural light and artificial indoor light is incident from the obverse side and reflected to achieve the display, and the transmissive display mode in which light from a light source is incident from the back side to achieve the display.
FIG. 9
is a cross-sectional view schematically representing the configuration of the above transflective liquid crystal display. As shown in the figure, the transflective liquid crystal display substantially comprises a front substrate
501
and a back substrate
502
, a liquid crystal
503
sealed in the space between these substrates, a light guide plate
505
to guide the light emitted from a light source
504
to the entire back substrate
502
, and a transflector
506
interposed between the light guide plate
505
and the back substrate
502
. The transflector
506
is a sheet with pearl pigment beads diffused in a resin which was disclosed in, for example, Japanese Unexamined Patent Application Publication No. 55-84975, and has the characteristic that a part of the incident light is reflected thereby; while the remaining part is transmitted therethrough. A polarizer
507
is bonded on the outer side (the side opposite to the liquid crystal
503
) of the front substrate
501
, and a color filter
508
, a transparent electrode
509
, etc. are formed on the inner side thereof. On the other hand, a polarizer
510
is bonded on the outer side (the side opposite to the liquid crystal
503
) of the back substrate
502
, and a transparent electrode
511
, etc. is formed on the inner side thereof.
In such a configuration, during reflective display mode, the external light such as the sunlight and artificial indoor light is incident from the front substrate
501
side, is transmitted via the polarizer
507
→the front substrate
501
→the color filter
508
→the transparent electrode
509
→the liquid crystal
503
→the transparent electrode
511
→the back substrate
502
→the polarizer
510
→the transflector
506
, is reflected by the transflector
506
, is transmitted along the same path in the reverse direction, and is then emitted from the front substrate
501
side, and observed by a user.
On the other hand, during transmissive display mode, the light emitted from the light source
504
is guided to the entire panel by the light guide plate
505
, a part of the light is transmitted through the transflector
506
and emitted from the front substrate
501
side via the polarizer
510
→the back substrate
502
→the transparent electrode
511
→the liquid crystal
503
→the transparent electrode
509
→the color filter
508
→the front substrate
501
→the polarizer
507
, and is observed by the user.
As described above, during reflective display mode, the light observed by the user (hereinafter, simply referred to as the “emitted light”) is transmitted through the color filter
508
twice. On the other hand, during transmissive display mode, the emitted light is transmitted through the color filter
508
only once. Assuming that the intensity of the light incident from the front substrate
501
is equal to the intensity of the light irradiated from the light source at the back substrate
502
, the color purity (the degree of coloring of the light) of the emitted light during transmissive display mode is substantially one half of the color purity of the emitted light during reflective display mode. If the color purity of the color filter
508
is improved, the color purity of the emitted light during transmissive display mode can be improved; however, under such conditions, a problem of reduced brightness during reflective display mode occurs. Thus, in the conventional transflective liquid crystal display, there is a problem in that color reproducibility during reflective display mode cannot be set to be the same as the color reproducibility during transmissive display mode.
Accordingly, the present invention has been made in light of the above problems, and an object of the present invention is to provide a liquid crystal display which can set the color reproducibility during reflective display mode to be the same as the color reproducibility during transmissive display mode, a manufacturing method thereof, and an electronic appliance.
SUMMARY OF THE INVENTION
In the present invention, there is provided a liquid crystal display having a liquid crystal held between a first substrate and a second substrate comprising a plurality of spacer units which are formed on a surface of the second substrate facing the first substrate and which have apertures, a plurality of reflectors which are formed on a surface of each of the spacer units, which reflect light transmitted through the first substrate, and which have apertures corresponding to the apertures of the spacer units, and a plurality of color filters having flat portions formed on a surface of each of the reflectors and a projected portion reaching the second substrate through the apertures in each reflector and each spacer unit.
Also in the present invention, there is provided a liquid crystal display having a liquid crystal held between a first substrate and a second substrate comprising a plurality of reflectors reflecting light transmitted through the first substrate which are formed on a surface of the second substrate facing the first substrate and which have apertures, a plurality of spacer units which are formed on a surface of each of the reflectors and have apertures corresponding to the apertures in the reflectors, and a plurality of color filters having a flat portion formed on a surface of each of the spacer units and a projected portion reaching the second substrate through the apertures in each of the reflectors and each of the spacer units.
In the present invention, during reflective display mode, the light incident from the first substrate is emitted after being transmitted through the flat portion of the color filter twice, and thus, the color reproducibility during reflective display mode is dependent on the thickness of the flat portion of the color filter. On the other hand, during transmissive display mode, the light irradiated from a light source (a backlight) is incident from the second substrate side, and emitted after being transmitted through the projected portion and the flat portion of the color filter, i.e., the apertures in the spacer unit and the reflector, and thus, the color reproducibility during transmissive display mode is dependent on the thickness of the projected portion and the flat portion of the color filter. Thus, the color reproducibility during reflective display mode and the color reproducibility during transmissive display mode can be independently set by individually selecting a thickness of the flat portion of the color filter and a thickness of the projected portion. Therefore, the color reproducibility during reflective display mode can be set to be the same as the color reproducibility during transmissive display mode.
The desired color reproducibility during transmissive display mode can be realized by adjusting a thickness of the projected portion, and a thickness of the projected portion can be easily adjusted by adjusting the thickness of the spacer unit. Even when the projected portion must be relatively thick in order to obtain the desired color reproducibility during transmissive display mode, there is an advantage in that the thickness of the projected portion sufficient for obtaining the desired color reproducibility can be ensured by forming the spacer unit of a predetermined thickness.
The second substrate may have a groove corresponding to each of the apertures, and the projected
Duong Tai
Harness & Dickey & Pierce P.L.C.
Kim Robert H.
Seiko Epson Corporation
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