Batteries: thermoelectric and photoelectric – Thermoelectric – Adjuncts
Reexamination Certificate
2000-01-19
2001-04-24
Gorgos, Kathryn (Department: 1741)
Batteries: thermoelectric and photoelectric
Thermoelectric
Adjuncts
C136S205000, C368S203000, C368S281000, C368S285000, C368S286000
Reexamination Certificate
active
06222114
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wrist-portable device having a thermoelectric power generator, such as a wrist watch.
2. Description of the Related Art
Of all wrist-portable devices such as wrist watches, electronic wrist watches are now the leading commodity, and most electronic wrist watches are powered by a silver oxide battery or a lithium battery.
However, these batteries are consumable supplies, and hence they need to be replaced periodically. In addition, the use of natural batteries leads to the consumption of limited natural resources and brings about environmental pollution when they are discarded.
To overcome these problems, wrist watches incorporating a power generation mechanism have been studied to replace battery-powered watches.
Known power generation mechanisms include a solar battery, a mechanical power generation mechanism and a thermoelectric power generation mechanism. The solar battery absorbs and converts the radiant energy of sunlight into electrical energy. The mechanical power generation mechanism utilizes gravitational energy. The thermoelectric power generation mechanism utilizes the Seebeck effect (the Peltier effect) based on a temperature difference. Of those mechanisms, watches powered by the solar battery and mechanical power generation have already been put in practical use.
On the other hand, the thermoelectric power generation mechanism is not yet commercially available although its principle has been known, as disclosed in Japanese Examined Patent Publication No. Hei 2-13279. It is still under study for practical use.
When thermoelectric power generation is utilized in a wrist-portable device, there is utilized a difference between the body temperature transferred to the wrist-portable device through the wrist (the high-temperature section) and the temperature of the air around the wrist-portable device (the low-temperature section).
However, the wrist-portable devices so far available have had problems of heat transfer from the high-temperature section to the heat receiving section of the thermoelectric generator and heat transfer from the radiation section of the thermoelectric generator to the low-temperature section, and these problems have prevented obtaining a temperature difference large enough to generate electric energy required for the thermoelectric generator.
The efficiency of radiation from the wrist-portable device to the outside air (low-temperature section) in particular fluctuates greatly, depending on how the wrist-portable device is worn or the like. For example, if part of the body is in contact with the radiation side of the wrist-portable device, the radiation section of the device does not radiate heat at all, and what is worse is that the radiation section absorbs heat, which is contrary to its purpose. Such problems may easily arise.
SUMMARY OF THE INVENTION
The present invention has been made to overcome the aforementioned problems. An object of the invention is therefore to provide a wrist-portable device with its power generation efficiency increased by eliminating the undesirable infiltration of heat from the radiation section of the thermoelectric generator.
To overcome the aforementioned problems, the following considerations have been given. Success of thermoelectric generation resides on how much heat can be absorbed and how well heat is radiated. When a wrist-portable device is worn, heat is absorbed not necessarily from the back cover but also from the glass, the bezel, the case bands and the like that should serve as a heat sink, due to heat contact or radiation.
According to the present invention, a guard for preventing undesirable heat contact is provided so as to prevent reverse infiltration of heat from the radiation section.
There is provided a wrist-portable device including a heat receiving section and a heat radiating section, and having a thermoelectric generator for generating predetermined electric energy taking advantage of a temperature difference between the heat receiving section and the heat radiating section, comprising:
an inner case band having a hollow portion vertically passing through the inner case band and being made of a material having a low heat conductivity;
a back cover for covering a lower end side of the hollow portion;
a glass for covering an upper end side of the hollow portion;
a bezel for holding a rim of the glass;
a radiation outer case band arranged on an upper surface of the inner case band, either fitted with the bezel so that heat can be transferred to the bezel or unitized with the bezel, and made of a material having a high heat conductivity; and
a radiation guard cover for covering a surface of at least one of the glass, the bezel and the radiation outer case band, the cover having a plurality of radiation holes and made of a material having a low heat conductivity.
According to this invention, the heat from the wrist is transferred to the heat receiving section of the thermoelectric generator through the back cover to thereby generate power, and is thereafter transferred to the glass, the bezel and the outer case band integrated with the bezel.
The transferred heat is radiated into the air from the outer surfaces of the glass, the bezel and the outer case band integrated with the bezel.
However, if a human body or a heat source should touch the bezel and the outer case band accidently, the radiating function is not performed in the conventional device, and what is worse is that heat is absorbed to stop power generation. The present invention employs a radiation guard cover for preventing accidental heat contact.
The heat from the radiation section is radiated into the outside air via meshes, striped slits or radiation holes formed in the radiation guard cover.
Therefore, even if a hand or the like touches the radiation section of the wrist-portable device accidently, the radiation section of the thermoelectric generator still can remove heat away from the generator, thereby allowing power generation to be maintained.
Here, the wrist-portable device includes electronic devices, such as wrist watches and pagers.
For example, plastics having a heat conductivity of 1 W/(m.° C.) or lower are the best low-heat-conductivity materials for the inner case band. However, if mechanical strength is an important factor, metals such as stainless steels and Ti having a heat conductivity of around 20 W/(m.° C.) can also be used as long as other conditions, such as the performance of the generator and the heat radiating performance of the radiation outer case band, are acceptable.
Further, metals such as Au, Ag, Cu and Al whose heat conductivity is as high as around 200 to 400 W/(m.° C.) are the best high-heat-conductivity materials for the radiation outer case band. However, copper alloys, etc., such as Bs whose heat conductivity is 100 W/(m.° C.) or higher can also be used as long as other conditions are acceptable.
Still further, in the present invention, the radiation cover is a plate having meshes or a plurality of holes which are shaped by straight lines or curved lines arranged in a decorative form.
According to this invention, if the radiation holes of the radiation guard cover are arranged effectively, the cover can radiate heat from the meshes or the radiation holes, and its portion other than these holes can prevent a hand or the like from directly touching the radiation section. In addition, an ornamental cover can be made, depending on how the meshes or the holes are arranged.
Here, plastics, e.g., whose heat conductivity is 1 W/(m.° C.) or lower are the best materials for the radiation guard cover. Particularly, high-strength resins such as urethane rubbers and polycarbonates are suitable.
If mechanical strength is an important factor, sheets and nets made of metals having relatively low heat conductivity, such as stainless steels and Ti whose heat conductivity is around 20 W/(m.° C.), may also be used.
Further, according to the present invention, the area totaling the surface areas passing the meshes or the
Adams & Wilks
Gorgos Kathryn
Parsons Thomas H
Seiko Instruments Inc.
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