U.S. patent number 3,874,163 [Application Number 05/402,664] was granted by the patent office on 1975-04-01 for liquid crystal display timepiece with variable contrast.
This patent grant is currently assigned to Kabushiki Kaisha Suwa Seikosha. Invention is credited to Osamu Ikeno.
United States Patent |
3,874,163 |
Ikeno |
April 1, 1975 |
Liquid crystal display timepiece with variable contrast
Abstract
Variable contrast in a watch using a liquid crystal display
panel for showing the time is achieved by the use of polarizer
sheets proximate both surfaces of said panel. The outer of said
sheets is mounted for rotation at the discretion of the wearer.
Inventors: |
Ikeno; Osamu (Suwa,
JA) |
Assignee: |
Kabushiki Kaisha Suwa Seikosha
(Tokyo, JA)
|
Family
ID: |
14633350 |
Appl.
No.: |
05/402,664 |
Filed: |
October 2, 1973 |
Foreign Application Priority Data
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|
|
|
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Oct 2, 1972 [JA] |
|
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47-114261 |
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Current U.S.
Class: |
368/242;
359/490.02; 968/931; 968/564; 968/882; 349/96; 349/58 |
Current CPC
Class: |
G02F
1/133528 (20130101); G04G 9/0035 (20130101); G04G
17/08 (20130101); G02F 1/133308 (20130101); G04C
17/00 (20130101) |
Current International
Class: |
G02F
1/13 (20060101); G02F 1/1335 (20060101); G04G
9/00 (20060101); G04G 17/00 (20060101); G04C
17/00 (20060101); G04G 17/08 (20060101); G04b
019/30 (); G02b 005/30 (); G02b 027/28 () |
Field of
Search: |
;58/5R,91R,127R
;350/159,16LC |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Jackmon; Edith Simmons
Attorney, Agent or Firm: Blum Moscovitz Friedman &
Kaplan
Claims
What is claimed is:
1. In an electronic timepiece including a field effect liquid
crystal panel for display of the time, the improvement comprising a
liquid crystal display panel having inner and outer faces, an inner
fixed plane-polarizer sheet proximate the inner face of said panel
and an outer plane-polarizer sheet proximate the outer face of said
panel, said outer sheet being mounted for manual rotation within
its plane whereby the contrast of said liquid crystal display may
be altered.
2. An electronic timepiece including a field effect liquid crystal
panel for display of the time, as defined in claim 1, wherein said
timepiece has an outer transparent crystal, said rotatable outer
sheet is mounted between said crystal and said outer face and
further comprising means for manually rotating said outer sheet
from the exterior of said timepiece.
3. An electronic timepiece including a field effect liquid crystal
panel for display of the time, as defined in claim 1, wherein said
timepiece has an outer transparent crystal and a manually rotatable
bezel and said outer sheet is mounted in said rotatable bezel for
rotation therewith exteriorly of said crystal.
4. An electronic timepiece including a field effect liquid crystal
panel for display of the time, as defined in claim 1, wherein said
timepiece has a manually displaceable transparent outer crystal and
said outer sheet is affixed to said displaceable crystal for
displacement therewith.
5. An electronic timepiece including a field effect liquid crystal
panel for display of the time, as defined in claim 4, wherein said
outer sheet is affixed to the inner face of said crystal.
6. An electronic timepiece including a field effect liquid crystal
panel for display of the time, as defined in claim 1, wherein said
timepiece has a crystal and said outer sheet is mounted for manual
rotation on said timepiece exteriorly of said crystal.
Description
BACKGROUND OF THE INVENTION
In view of the intense competition in the sales of watches, every
feature whether primarily decorative or primarily utilitarian from
the standpoint of use of the watch, has utility with respect to
sales if it can attract the eye of a possible purchaser or if it
can give an appearance of superiority with respect to some
characteristic. With such considerations in view, watch cases in
general and dials in particular were metamorphosed through a myriad
of variations.
Recently, a number of types of illuminated digital displays have
been incorporated into watches to take the place of the usual
dials. Of particular interest are those displays using
light-emitting diodes and liquid crystals. In general, the latter
type of display is preferred because of the fact that it uses less
energy. This problem is sufficiently serious so that most, but not
all, electronic timepieces featuring illuminated digital displays
actually show the time only when deliberately switched into
actuation.
A type of liquid crystal display which has already become part of
the art features a pair of polarizing sheets such as those sold
under the tradename of Polaroid. The amount of light transmitted by
such sheets depends on the angle between the axes of polarization
of the two polarizing sheets as incorporated in a watch. However,
in the prior art constructions the angle between the planes of
polarization of the two sheets has been fixed so that it is not
possible to vary the degree of contrast obtainable by means of such
a device in accordance with the desire or whim of the wearer.
Particularly, it is not possible to adapt the combination of the
two sheets to the level and angle of illumination where the watch
is being used.
SUMMARY OF THE INVENTION
In a timepiece featuring a liquid crystal display panel, polarizing
plates of the plane-polarizing type are placed proximate the inner
and outer surfaces of the liquid crystal display panel. The
polarizing sheet proximate the outer face of the panel is mounted
for rotation, making it possible to vary the contrast with which
the display is shown.
Accordingly, an object of the present invention is a timepiece in
which the time is displayed by a liquid crystal display panel
wherein plane-polarizing sheets are disposed at the inner and outer
faces of the display panel and the outermost sheet is mounted for
rotation.
Another object of the present invention is a timepiece in which a
liquid crystal display panel is used for the display of time
wherein plane-polarizing sheets are mounted proximate the inner and
outer faces of said display panel and the outer sheet can be
rotated for the purpose of varying the degree of contrast of the
display.
A further object of the present invention is a timepiece in which
the time is displayed by a liquid crystal display panel wherein a
pair of plane-polarizing sheets are mounted at the inner and outer
faces of said display panel, the outer most sheet of said pair
being mounted for rotation in its own plane and at the interior
face of a watch crystal, means being provided for rotating said
outermost sheet from the exterior of said watch.
Still other objects and advantages of the invention will in part be
obvious and will in part be apparent from the specification.
The invention accordingly comprises the features of construction,
combination of elements, and arrangement of parts which will be
exemplified in the construction hereinafter set forth, and the
scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the invention, reference is had to
the following description taken in connection with the accompanying
drawings, in which:
FIG. 1 is a sectional view of a timepiece in accordance with the
prior art wherein a pair of plane-polarizing sheets are mounted at
the interior and exterior faces of a liquid crystal panel, the
angle between the axes of said sheets being fixed;
FIG. 2 is a sectional view of a timepiece in accordance with the
present invention wherein the outermost of the two polarizing
sheets is internal to the timepiece and is rotatable by means
operable from the exterior of said timepiece;
FIG. 3 represents the appearance of the display panel when the
planes of polarization of said polarization sheets make an angle of
90.degree. with each other;
FIG. 4 represents the appearance of the display panel when the
planes of polarization of the polarization sheets coincide;
FIG. 5 is a sectional view of a timepiece wherein the outermost of
a pair of polarizing sheets is mounted exterior to the crystal of
said timepiece; and
FIG. 6 is an embodiment of a timepiece in accordance with the
present invention wherein the outermost of the pair of polarizing
sheets is mounted at the interior surface of the crystal of said
timepiece.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In a conventional field effect liquid crystal display timepiece as
shown in FIG. 1, plane-polarizing sheets 2 are secured to the inner
and outer faces of display panel 1 by adhesive or the like. In such
a construction, once the angle between the planes of polarization
of the two polarizing sheets is established as is done during
construction, it becomes difficult if not impossible to vary the
contrast of the display by varying the angle between the planes of
polarization of the two sheets. Consequently, design interest
obtainable from such an arrangement is minimal.
To increase the design interest of such an array, it is desirable
that at least one of the polarizing sheets be mounted in such a way
as to be rotatable in its own plane. An example of such an
embodiment is shown in FIG. 2 wherein polarizing sheets 4a and 4b
are mounted on either side of a liquid crystal display panel 3. The
outermost sheet 4a is joined to a rotatable member 6 within
watchcase 5. The join can be made by adhesive or by a snap fit or
similar means. Rotatable member 6 is in the form of a crown gear
which can be rotated around its axis by rotating crown 7 exterior
to the watch and thereby rotating spur gear 8. By this means, the
angle between the planes of polarization of the outer polarizing
sheet 4a and the inner polarizing sheet 4b can be altered. When the
planes of polarization of the two sheets differ by 90.degree. the
appearance of the display is as shown in FIG. 3. When the planes
coincide, the level of illumination of the background and the
digits is reversed so that the appearance of the display is as
represented in FIG. 4. Moreover, variation of the angle between the
planes of polarization, especially when near 0.degree. and
90.degree. makes it possible to vary the degree of contrast between
the background and the digits.
In the embodiment of FIG. 5, the outermost polarizing sheet 4a is
affixed to a rotatable member 9, such as a bezel, which is on the
outside of case 5. In such an arrangement, the sheet 4a is exterior
to crystal 10. The method of attachment of rotatable member 9 to
watchcase 5 may vary; a snap fit (not shown) is desirable in that
member 9 and sheet 4a may readily be removed from the watch if
desired.
A further embodiment of the invention is shown in FIG. 6 wherein a
polarizing sheet 4a is joined to the interior of the timepiece
crystal 10 as by adhesive. As a general rule, crystal 10 cannot
readily be rotated so that when a particularly desirable
orientation is found by the wearer, it can be maintained. However,
crystal 10 is generally made to be removable with relative ease so
that it is possible without serious difficulty to alter the plane
of polarization of polarizing sheet 4a when the glass is circular,
and even when it is square.
In the embodiments of FIGS. 2, 5 and 6 a projection may be affixed
to one or the other of the rotatable members so that a desirable
location may be restablished if an accidental displacement occurs.
Alternatively, detents may be used to assure exact location and to
prevent accidental displacement.
In summary, the combination of the pair of polarizing sheets with a
field effect liquid crystal display panel where one of the
polarizing sheets is rotatable makes it possible to vary the
appearance of the display and to provide novel effects, thereby
making timepieces incorporating such a construction relatively
attractive.
It will thus be seen that the objects set forth above, among those
made apparent from the preceding description, are efficiently
attained and, since certain changes may be made in the above
constructions without departing from the spirit and scope of the
invention, it is intended that all matter contained in the above
description or shown in the accompanying drawings shall be
interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended
to cover all of the generic and specific features of the invention
herein described, and all statements of the scope of the invention
which, as a matter of language, might be said to fall
therebetween.
* * * * *