Horology: time measuring systems or devices – Chronological – With electro-optical display
Reexamination Certificate
1999-03-26
2001-09-18
Miska, Vit (Department: 2859)
Horology: time measuring systems or devices
Chronological
With electro-optical display
C368S234000, C368S242000, C368S082000, C349S096000, C349S106000
Reexamination Certificate
active
06292439
ABSTRACT:
TECHNICAL FIELD
The invention relates to a timepiece (watch and clock) for displaying at least time information such as hour, minute, and second, or calendar information such as date, days of the week, month, and year by use of a liquid crystal display panel. The time piece includes not only a timepiece for indicating digital display of time information and calendar information but also a combination timepiece capable of indicating digital display and analog display of time information by hands, and an analog timepiece for displaying time scales and so forth on the dial thereof utilizing a liquid crystal display panel, or for indicating simulated hands for an hour hand, a minute hand, and a second hand.
BACKGROUND TECHNOLOGY
A timepiece for indicating digital display of time information such as hour, minute, and second, and calendar information such as date, days of the week, month, and year, by use of a liquid crystal display panel, has been in widespread use for wrist watches and clocks, provided with a crystal oscillation circuit.
There has also been in use a combination timepiece wherein an analog display indicating time information by the hands of the watch is used in combination with digital display indicating time information and calendar information in numbers and letters.
Further, there has been proposed an analog watch for selectively displaying markers in various patterns, or for displaying simulated hands for an hour hand, a minute hand, and a second hand, by making up the dial thereof based on a liquid crystal display panel (refer to, for example, Japanese Patent Laid-open S 54-153066).
In a conventional liquid crystal display panel for displaying time information and calendar information, as in a watch or clock, a liquid crystal cell filled with liquid crystals is sandwiched between two transparent substrates each having an electrode on an inner facing surface thereof, and an upper polarizing film and a lower polarizing film are disposed, respectively, on the external opposite surface of each transparent substrate. If an electric field is applied to the liquid crystals by applying a voltage to the pair of electrodes on the transparent substrates holding the liquid crystal cell therebetween, the optical property of the liquid crystals is changed, thereby locally controlling transmission and absorption of light falling on the liquid crystal display panel such that a predetermined display is effected.
Each of the upper polarizing film and the lower polarizing film is a polarizing film absorbing the light linearly polarized in the direction orthogonal to the transmission axis thereof.
In the case of a watch using the conventional liquid crystal display panel described above, time information and calendar information are displayed in dark against a white background in the normally white mode that is common.
However, by simply displaying time information and calendar information in dark against the white background as described in the foregoing, neither variation in design nor fun of use can be offered, leading to rapid decline in product popularity among consumers. Probably as a result, consumption of digital watches has recently been on the decline, and neither combination timepieces nor analog watches with liquid crystal display panels have received market acceptance.
The invention has been developed in light of the present situation as described, and an object thereof is to provide a timepiece (watch or clock) capable of providing variation in design while indicating digital display or analog display by use of a liquid crystal display panel.
DISCLOSURE OF THE INVENTION
To this end, the invention provides a timepiece provided with a liquid crystal display panel, capable of displaying at least time information or calendar information, and the liquid crystal display panel is made up as follows.
An absorption-type polarizing film for absorbing the light linearly polarized in the direction orthogonal to the transmission axis thereof is disposed on the visible side of the liquid crystal cell, having a liquid crystal layer sealed in between a pair of transparent substrates, each having an electrode on the inner facing surfaces thereof, while a reflection-type polarizing film for reflecting the light linearly polarized in the direction orthogonal to the transmission axis thereof is disposed on the side of the liquid crystal cell opposite from the visible side thereof.
Further, a color filter is disposed on the visible side of the absorption-type polarizing film, or between the absorption-type polarizing film and the reflection-type polarizing film.
Further, a light absorption film may be disposed on the side of the reflection-type polarizing film, opposite from the visible side thereof. Further, a light scattering film may be disposed on the visible side of the absorption-type polarizing film. Further, a backlight may be disposed on the side of the reflection-type polarizing film, opposite from the visible side thereof. In the latter case, a translucent film may be disposed between the reflection-type polarizing film and the backlight. An absorption-type polarizing film may be used as the translucent film.
In the liquid crystal display panel having the backlight disposed therein, a light scattering film may be disposed on the visible side of the absorption-type polarizing film.
In the aforementioned liquid crystal display panels, the absorption-type polarizing film is, preferably, disposed on the visible side of the liquid crystal cell such that the transmission axis of the absorption-type polarizing film is parallel with the direction of the long axes of liquid crystal molecules located on the visible side of the liquid crystal layer in the liquid crystal cell, while the reflection-type polarizing film is, preferably, disposed such that the transmission axis thereof is parallel with, or orthogonal to the direction of the long axes of liquid crystal molecules located on the side opposite from the visible side of the liquid crystal layer in the liquid crystal cell.
Alternatively, the absorption-type polarizing film is disposed on the visible side of the liquid crystal cell such that the transmission axis of the absorption-type polarizing film may be orthogonal to the direction of the long axes of liquid crystal molecules located on the visible side of the liquid crystal layer in the liquid crystal cell while the reflection-type polarizing film is disposed such that the transmission axis thereof may be in parallel with, or orthogonal to the direction of the long axes of liquid crystal molecules located on the side opposite from the visible side of the liquid crystal layer in the liquid crystal cell.
(These conditions are particularly indicated when using a twisted nematic liquid crystal layer having a twist angle of 90°)
As the color filter of the aforementioned liquid crystal display panel, it is preferable to use the following:
1) a selective transmission color filter for transmitting a light component substantially at a specified wavelength only;
2) a color polarizing film capable of transmitting a component of the light linearly polarized in the direction orthogonal to the transmission axis thereof, at a specified wavelength only, and absorbing light components of the linearly polarized at other wavelengths while transmitting all components of the light linearly polarized light in the direction parallel with the transmission axis thereof;
3) a dielectric multi layer film capable of reflecting a light component of incoming light having a specified wavelength, while transmitting light components of the incoming light at other wavelengths.
The liquid crystal layer of said liquid crystal cell may be composed of any from among a twisted nematic liquid crystal layer, a supertwisted nematic liquid crystal layer, and a guest host liquid crystal layer.
The color filter of the liquid crystal display panel may be disposed between the absorption-type polarizing film and the liquid crystal cell or may be disposed between the liquid crystal cell and the reflection-type polarizing fil
Akiba Yuichi
Akiyama Takashi
Ide Masafumi
Kikuchi Masami
Nakagawa Koji
Armstrong Westerman Hattori McLeland & Naughton LLP
Citizen Watch Co. Ltd.
Goodwin Jeanne-Marguerite
Miska Vit
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