Horology: time measuring systems or devices – Power supply details – Electrical
Patent
1997-04-18
2000-02-01
Roskoski, Bernard
Horology: time measuring systems or devices
Power supply details
Electrical
368232, G04B 100
Patent
active
060210990
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a dial for use in a solar-cell watch.
PRIOR ART
The solar cell has long been used as a power source in, for example, watches, electronic calculators and portable radios. The solar cell is commonly formed of amorphous silicon or the like and converts light energy to electric energy. For accomplishing its function, the solar cell must be disposed in a light receiving area, namely, a surface area which is directly sighted from outside. However, the solar cell is generally brown or dark-blue, so that, for example, the dial also must be brown or dark-blue. Therefore, a watch having a power source which relies on the solar cell has very limited freedom in the design including the tone of the watch.
A watch in which an interference filter or the like is provided on the frontal surface of a solar cell so that directly sighting of the solar cell is prevented has been proposed for coping with the above problem. However, the proposed watch has encountered the problems that the supply of light energy to the solar cell is hindered and that the watch dial has poor appearance quality.
In the efforts toward solving these problems, for example, Japanese Patent Publication No. 5(1993)-38464 discloses a colored solar cell comprising a solar cell and a color diffusion layer, this color diffusion layer comprising a color filter provided on the frontal surface of the solar cell and capable of transmitting radiations of the wavelength range contributory to the power generation of the solar cell and a scattering layer provided between the solar cell and the color filter and capable of transmitting part of the light having passed through the color filter while scattering the rest of the light in all directions. It is described that, in the preparation of a white diffusion plate, the scattering layer is formed of a milky acrylic plate, a half mirror coated with a delustering clear lacquer, a one-side roughened glass or plastic having a mirror of, for example, aluminum provided on the other side or the like. However, the milky acrylic plate not only suffers from burring at the time of working to thereby necessitate deburring with the result that a cost increase is caused but also has a drawback in that a thermal deformation is caused by the exposure thereof to direct sunlight for a prolonged period of time. Further, the half mirror coated with a delustering clear lacquer and the one-side roughened glass or plastic having a mirror of, for example, aluminum provided on the other side encounter the problem that the film thickness is so irregular that the light transmission is dispersed to thereby invite color shading. Moreover, all of the above materials disadvantageously have poor appearance quality in the use as a watch dial.
In Japanese Patent Application No. 6(1994)-32463, the same inventor proposed a watch equipped with a dial comprising a solar cell and a covering member having level differences and recessed channels on its back. In this covering member, level differences and recessed channels of minute pitches are formed at equal intervals on one side of a ceramic plate so that light is irregularly reflected to thereby make it difficult to sight the solar cell arranged on the lower side of the covering member. However, this covering member can be fabricated only with the use of high precision working jigs.
The present invention has been made taking the above current situation into account. Thus, an object of the present invention is to provide a solar-cell watch dial which can prevent the solar cell from being sighted from outside and which does not hinder the supply of light energy to the solar cell. Another object of the present invention is to provide a solar-cell watch dial which can diversify the design of the solar-cell watch.
SUMMARY OF THE INVENTION
The solar-cell watch dial of the present invention is disposed on or above a solar cell housed in a watch, comprises an alumina of the formula Al.sub.2 O.sub.3 whose purity is at least 99.90% and exhibits a light
REFERENCES:
patent: 5761158 (1998-06-01), Azuma et al.
Japanese Patent Publication No. 56163266 Abstract, Dec. 15, 1981, 1 p., English-language.
Swiss Patent No. 522 247, Nov. 30, 1971, p. 1 only, Swiss language.
Aoki Akio
Azuma Akira
Kobayashi Ikuo
Murata Toshio
Saito Takao
Cimeo Precision Co., Ltd.
Citizen Watch Co. Ltd.
Roskoski Bernard
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