Horology: time measuring systems or devices – Displays or display device details – Optical
Reexamination Certificate
2000-09-06
2002-05-07
Miska, Vit (Department: 2859)
Horology: time measuring systems or devices
Displays or display device details
Optical
C349S096000, C349S104000, C349S113000, C359S487030, C359S506000
Reexamination Certificate
active
06385139
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to display devices for displaying characters, numerals, patterns and so forth. In addition, the present invention relates to electronic timepieces, such as wristwatches, stopwatches and so forth using the display devices. More specifically, the present invention relates to a display technology such as a liquid crystal device for displaying information by selecting one of the states of changing and not changing of a transmitted light polarization axis of a trasmitted linearly polarized light component.
2. Description of the Related Art
As a device for effecting display using external light, a digital-display-type timepiece using a liquid crystal device is most common. As such an electronic timepiece, one is conventionally known in which a first polarizer, a trasmitted light polarization axis changing optical element (transmitted light polarization axis changing means), such as a liquid crystal device, capable of selecting one of the states of changing and not changing a transmitted light polarization axis of a transmitted linearly polarized light component, a second polarizer, and a reflector plate are deposited in that order. In the liquid crystal device, for example, a TN (Twisted Nematic) liquid crystal, an STN (Super-Twisted Nematic) liquid crystal, an ECB (Electrically Controlled Birefringence) liquid crystal, or the like is used.
SUMMARY OF THE INVENTION
In the thus-constructed electronic timepiece (display device), both of the first and second polarizers transmit a linearly polarized light component in the direction of the transmitted light polarization axis of incident light, while they absorb a linearly polarized light component in the direction of an absorption axis intersecting perpendicularly to the direction of the transmitted light polarization axis. Accordingly, when the external light enters into the first polarizer and only the linearly polarized light component of the transmitted light polarization axis in a first direction enters into the transmitted light polarization axis changing optical element, one of the linearly polarized light component passing through an area for changing the transmitted light polarization axis, and the linearly polarized light component passing through an area for not changing the transmitted light polarization axis is absorbed by the second polarizer, and the other linearly polarized light component is transmitted by the second polarizer to reach the reflector plate. Therefore, only the light reflected by the reflector plate, that is, only the light passing through one of areas in the area for changing the transmitted light polarization axis and the area for not changing the transmitted light polarization axis of the transmitted light polarization axis changing optical element is transmitted by the transmitted light polarization axis changing optical element and the first polarizer, so that the time can be visually recognized.
In this way, according to the conventional electronic timepiece, only the light transmitted by one of the area for changing the transmitted light polarization axis, and the area for not changing the transmitted light polarization axis in the transmitted light polarization axis changing optical element is reflected by the reflector plate, and is transmitted by the transmitted light polarization axis changing optical element and the polarizer to contribute to display. In contrast, the light transmitted by the other area is absorbed by the second polarizer, or is transmitted by a polarization beam separation element, and does not contribute to display. Accordingly, the conventional electronic timepiece has a problem in that a segment portion or a background portion of the display is dark. In addition, for the same reason, the conventional electronic timepiece has a problem in that it is mechanically difficult to improve the esthetic design function of the electronic timepiece, such that it is difficult to make both the segment portion and the background portion mirrored, satined, or colored.
In view of the foregoing problems, an object of the present invention is to realize a display device which is constructed so that even a linearly polarized light component transmitted by any one of the area for changing a transmitted light polarization axis, and the area for not changing the transmitted light polarization axis is emitted toward a user, thereby effecting high visibility display utilizing external light, and which can effect reflective display with a combination of various textures and color tones, and to realize an electronic timepiece using the same.
In order to solve the above problems, in an exemplar of embodiment the invention, as shown in
FIG. 1
, firstly, a first characteristic of a display device
10
is that a first polarized-light separating member
2
for transmitting a linearly polarized light component polarized in a first direction of incident light and for not transmitting a linearly polarized light component perpendicularly intersecting the linearly polarized light component, a transmitted light polarization axis changing device
3
capable of selecting one of a first state of changing and a second state of not changing a transmitted light polarization axis when the incident linearly polarized light component is transmitted, a second polarized-light separating member
4
for transmitting a linearly polarized light component in a second direction of incident linearly polarized light components and reflecting a linearly polarized light component in a third direction perpendicularly intersecting the second direction, and a reflecting element
5
capable of reflecting the linearly polarized light component transmitted by the second polarized-light beam separating member
4
toward the second polarized-light separating member
4
are disposed in that order. In addition, according to the present invention, a second characteristic is that a modified layer (for example, a back-side coloring layer
71
, a surface-side coloring layer
72
, a back-side light-diffusing layer
91
, and a surface-side light-diffusing layer
92
) for emitting light incident on the second polarized-light separating member
4
by changing optical characteristics is formed on at least one of a surface
41
facing the transmitted light polarization axis changing device
3
of the second polarized-light separating member
4
and a back
42
facing the reflecting element
5
.
In the thus-constructed display device
10
, predetermined information can be displayed by first return light reflected by the reflecting element
5
to be transmitted by the second polarized-light separating member
4
, the transmitted light polarization axis changing means
3
, and the first polarized-light separating member
2
, and second return light reflected by the second polarized-light separating member
4
to be transmitted by the transmitted light polarization axis changing device
3
and the first polarized-light separating member
2
in the light incident on the first polarized-light separating member
2
from the opposite side of the transmitted light polarization axis changing device
3
.
That is, according to the present invention, each light transmitted by an area in the first state of changing the transmitted light polarization axis and transmitted by an area in the second state of not changing the transmitted light polarization axis in the transmitted light polarization changing device
3
is emitted as a linearly polarized light component (first return light) reflected by the reflecting element
5
to be transmitted by the second polarized-light separating member
4
, the transmitted light polarization axis changing device
3
, and the first polarized-light separating member
2
, and as a linearly polarized light component (second return light) reflected by the second polarized-light separating member
4
to be transmitted by the transmitted light polarization axis hanging device
3
and the first polarized-light separating member
2
, and contribute to di
Arikawa Yasuo
Matsui Tsuyoshi
Miska Vit
Seiko Epson Corporation
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