JP2000162341A - Electronic clock with solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide new structure of an electronic clock with a solar cell that can be manufactured by lower costs than before. SOLUTION: A solar cell 11 that is provided at a light reception part 11 is provided with two generation parts 11a, where the two generation parts 11a are connected in series. Back flow check circuit 12 consisting of a diode or the like is connected to a light reception part 10, the back flow check circut 12 is connected, and then an output terminal 11b and an output terminal piece 11c are provided. A clock movement 20 that is arranged at the reverse side of the light reception part 10 is provided with a chemical secondary battery 21 that is connected to the above output terminal 11b, a clock control circuit 22 that is connected to both the ends of the chemical secondary battery 21, and a clock drive part 24. The clock control circuit 22 is in the same configuration as a normal battery clock and does not include any additional functions for a clock with solar cell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic timepiece with a solar cell.

[0002]

2. Description of the Related Art Conventionally, there has been provided an electronic timepiece with a solar cell in which a solar cell is arranged on a dial surface of a time display section, and light is applied to the solar cell to generate power and drive a clock movement. is there. This electronic timepiece with a solar cell converts external light into electric power, thereby eliminating the need for battery replacement, and is often sold as a wristwatch.

FIG. 8 is a block diagram showing a configuration of a power supply system of the electronic timepiece with a solar cell. However, the configuration block diagram shown in FIG. 8 shows the actual circuit configuration in a greatly simplified manner. The solar cell 81 installed in the light receiving section 80 is composed of a silicon semiconductor layered structure laminated on, for example, a disk-shaped support substrate made of stainless steel, and includes four power generating sections each having a light receiving electrode section on the dial surface. An output terminal 81b is provided on the back side of the circuit board connected to the support board. On the other hand, a clock movement 90 installed on the back side of the light receiving unit 80 includes a large-capacity capacitor 91 for storing the power generated by the solar cell 81, a clock control circuit 92 for controlling the clock operation, and an auxiliary capacitor 93.
And a clock motor 94 including a drive motor for rotating the hands and a liquid crystal display circuit for driving the liquid crystal display panel.

In the above-described circuit configuration, the configuration specific to the electronic timepiece with a solar cell includes a backflow prevention circuit 95 composed of a diode and the like attached to the solar cell 81 with respect to the large-capacity capacitor 91, Output terminal 8
A limiter circuit 96 connected between 1b and 81c, a charge / discharge control circuit 97 connected to a large-capacity capacitor 91,
And a booster circuit 98 provided between the large-capacity capacitor 91 and the clock control circuit 92. Each of these circuits, together with the clock control circuit 92, is configured as a dedicated IC for an electronic timepiece with a solar cell.

In the electronic timepiece with a solar cell, when the charging voltage of the large-capacity capacitor 91 becomes higher than the output voltage of the solar cell 81, the backflow preventing circuit 95 prevents the backflow of the current. When the charging voltage of the large-capacitance capacitor 91 exceeds the withstand voltage, the limiter circuit 96 is a short-circuit between both electrodes of the output terminal of the solar cell 81 to prevent overcharging of the large-capacity capacitor 91 by overcharge prevention means. is there. The charge / discharge control circuit 97 is a circuit for controlling charging and discharging of the large-capacity capacitor 91 in accordance with the storage voltage of the large-capacity capacitor 91, and is used for supplying sufficient power from the solar battery 81 to the clock control circuit 92 and the like. If there is no problem, the large-capacity capacitor 91 is charged, and if the power supply from the solar battery 81 to the clock control circuit 92 and the like is likely to be insufficient, the large-capacity capacitor 91 is discharged. The charge / discharge control circuit 97 includes a large-capacity capacitor 91
When the solar cell 81 has just started to generate power, the start time shortening means for suppressing the charging of the large-capacity capacitor 91 is also configured to make the clock drive start as soon as possible. The booster circuit 98 is a circuit for increasing the voltage on the primary side and supplying it to the clock body.
When the power generation voltage of the solar cell 81 is low and the charging voltage of the large-capacity capacitor 91 is low, the driving time of the clock body is extended by boosting.

[0006]

However, in the above electronic timepiece with a solar cell, it is necessary to construct a special timepiece movement having a built-in exclusive IC having a function necessary only when the electronic timepiece has a solar cell as described above. Because there is not much in comparison with the clock which needs a general battery exchange,
There is a problem that the manufacturing cost increases. In particular, since the light receiving portion near the dial needs to have a special structure in order to incorporate the solar cell, the manufacturing cost as a whole is greatly increased as compared with a normal battery timepiece.

Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an electronic timepiece with a solar cell.
An object of the present invention is to provide a novel structure that can be manufactured at a lower cost than before.

[0008]

Means taken by the present invention to solve the above-mentioned problem is to provide a timepiece movement having a function necessary to operate by receiving power supply from a primary battery. Equipped with a rechargeable power storage means instead of a primary battery, provided with an output terminal connected to the power storage means and having a maximum generated voltage equal to or higher than the minimum operation voltage of the timepiece movement, and a power generation unit connected in two stages. A solar cell having a structure formed by connection and a backflow prevention circuit connected between the solar cell and the power storage means are provided, and the power storage means is a secondary battery and corresponds to the maximum power generation voltage. An electronic timepiece with a solar cell, wherein a maximum charging voltage value to the power storage means is configured to be equal to or lower than a rated voltage value of the power storage means.

According to this means, the timepiece movement for the battery timepiece is provided with the power storage means, and the solar cell having the maximum generated voltage equal to or higher than the minimum operating voltage of the timepiece movement and the backflow prevention circuit are provided, so that the solar cell has A timepiece can be configured, and the solar cell has a structure in which the power generation unit is connected in two stages in series, so that the maximum charging voltage can be reduced and the generated current can be increased. The charging characteristics of the storage means as a battery are improved, the start time from the discharge state can be shortened, and the maximum charging voltage corresponding to the maximum power generation voltage of the solar cell is equal to or less than the rated voltage of the storage means. In addition, it is possible to prevent the characteristics of the power storage means from being deteriorated, thereby achieving cost reduction and long life of the power storage means. Therefore, when configuring a timepiece with a solar cell, it is not necessary to separately manufacture a timepiece movement equipped with a dedicated circuit as in the related art, and some of the components of the dedicated circuit (immediate start circuit, booster circuit, overvoltage This eliminates the need for providing a charge prevention circuit, etc., and allows a general-purpose timepiece movement to be used as it is, thereby significantly reducing manufacturing costs.

[0010] In the first aspect, it is preferable that the power storage means and the timepiece movement have a structure in which a solar cell module having the backflow prevention circuit is connected to the power storage means and the timepiece movement. By having a structure formed by connecting a solar cell and a solar cell module provided with a backflow prevention circuit, it is possible to assemble simply by mounting the solar cell module on a normal watch movement, so that the assembly process can be simplified, and Manufacturing costs can be reduced.

Next, a solar cell, a power storage means for storing power generated by the solar cell, and a clock movement operated by power supplied from the solar cell or the power storage means, wherein the power storage means and the clock movement In contrast, the solar cell module has a structure in which a solar cell module including a solar cell, a backflow prevention circuit connected to the solar cell, and an output terminal connectable to the power storage means is connected. It is an electronic timepiece with a solar cell. Since it can be configured simply by connecting a solar cell module equipped with a solar cell and a backflow prevention circuit to a watch movement, it can be used for various watch movements as a solar cell module, and is not a specially designed watch movement. It is also possible to use a movement having only the functions of a normal battery timepiece, so that the manufacturing cost can be reduced.

[0012] In the second or third aspect, the solar cell module may include a holding member for holding a component thereof, and the holding member may be configured to be engageable with the timepiece movement. preferable. Since the holding member of the solar cell module is configured to engage with the timepiece movement, the connection between the solar cell module and the timepiece movement is facilitated, and each part of the solar cell module is held by the holding member. Therefore, handling in the manufacturing process is also facilitated. In this case, it is particularly preferable that the output terminal is naturally electrically connected to the power storage means when the holding member is engaged with the timepiece movement.

The solar cell according to any one of claims 2 to 4, wherein the solar cell has a laminated structure on an insulating substrate, and the output terminal is drawn out through a through hole formed in the insulating substrate. It is preferable to be provided on the back surface of the insulating substrate so as to be connected to the conductor.
By being connected to the conductor drawn out through the through hole of the insulating substrate and being provided on the back surface of the insulating substrate, the conductive connection to the power storage means is facilitated and the solar cell is insulated separately at the outer periphery. Since there is no need to attach a substrate, the internal structure of the timepiece can be reduced in size.

[0014] In any one of claims 3 to 5, it is preferable that the power storage means is a secondary battery having a flat region in discharge voltage characteristics. By having a flat region in the discharge voltage characteristics, fluctuations in output voltage during discharge are suppressed, so that the timepiece can be directly stored without using a booster circuit, etc., compared to using a capacitor without a flat region. No problem occurs even when driven by means. Here, the flat region refers to a region where the discharge capacity is not proportional to the output voltage, which is generally seen in the discharge characteristics of a chemical secondary battery, and does not necessarily mean that the output voltage is strictly constant. For example, it refers to a region where the ratio of the discharge capacity to the maximum storage capacity is 50% or more, and furthermore, the fluctuation range of the output voltage is 50% or less of the output voltage in the region.

[0015] In claim 6, it is preferable that the maximum generated voltage of the solar cell is substantially equal to the voltage value of the flat region in the secondary battery. By making the maximum generated voltage of the solar cell substantially equal to the voltage value in the flat region, that is, the output voltage value of the secondary battery in the flat region of the discharge characteristics, the secondary battery cannot be completely charged. However, the rechargeable battery can be charged to an extent sufficient for clock operation, and in this case, the generated voltage of the solar cell cannot exceed the withstand voltage of the rechargeable battery. can do. Here, the maximum generated voltage of the solar cell referred to in claims 1 and 7 is a maximum output voltage obtained in a normal use state of the timepiece, and is not a normal use obtained only by artificial light irradiation. Do not consider the voltage value of the case. In this case, in particular,
By making the maximum power generation voltage of the solar cell substantially equal to the highest discharge voltage value in the flat region, the charge rate of the chemical secondary battery can be increased without any trouble.

Preferably, the secondary battery has a characteristic in which the output voltage temporarily increases at the start of charging in a low charge state.
With this characteristic, when the secondary battery is in a low charge state that cannot drive the timepiece movement, power is started from the solar battery and the secondary battery is temporarily charged when the secondary battery starts to be charged. Since the output voltage of the secondary battery rises, it is possible to drive the clock movement by this voltage rise, so that the start time (operation start time) of the clock movement can be shortened. It is no longer necessary to provide a means for shortening the start time that is unique to watches.
Initial movement performance can be improved.

In any one of claims 6 to 8, the secondary battery has a flat region sufficient to be a lithium ion secondary battery and has the characteristics described in claim 8. It is desirable because it has. In particular, a titanium lithium ion secondary battery described below is most desirable.

In each of the above means, the solar cell includes a plurality of power generation units connected in series, and the power generation units are connected in series in order to limit the maximum generated voltage of the solar cell to a withstand voltage of the power storage means or less. It is preferable to set the number of connections. Since the maximum generation voltage of the solar cell is suppressed by setting the number of series connection of the power generation unit, a circuit for lowering the charging voltage to the secondary battery is not required, and the output voltage is large instead of being suppressed. Since the current can be taken out, the fluctuation of the supply voltage can be suppressed, and the charging efficiency of the secondary battery in the low charging state can be improved.

It is preferable that each of the above means does not include an overcharge prevention means for the power storage means. Further, it is preferable that each of the above-mentioned means does not include a start time reducing means for hastening the operation start time of the timepiece movement when the amount of power stored in the power storage means is small. Furthermore, in each of the above means, it is preferable that a booster circuit is not provided between the power storage means and the clock body.

In each of the above means, the number of the power generation units connected in series in the solar cell is preferably two, that is, two stages. As a result, in a solar cell using ordinary amorphous silicon, the maximum power generation voltage is about 1.6 V, and a maximum charging voltage or operating voltage of 1.4 V can be obtained even in consideration of the voltage drop of the backflow prevention circuit. , While being able to fully operate the watch movement in a normal battery watch,
Overcharging of the storage means can be avoided.

The secondary battery of the present invention is preferably a chemical secondary battery such as a lithium ion secondary battery, but may be any other chemical secondary battery or a secondary battery other than a chemical secondary battery. In addition, any rechargeable element having a flat discharge characteristic similar to the discharge characteristics of a lithium ion secondary battery is included.

[0022]

Next, an embodiment according to the present invention will be described in detail. FIG. 1 is a configuration block diagram of a power supply system of the present embodiment, which is an electronic wristwatch with a solar cell.
In this embodiment, the solar cell 1 provided in the light receiving unit 10
One is provided with two power generation units 11a, which are connected in series. A backflow prevention circuit 12 composed of a diode or the like is connected to the light receiving unit 10, and after the backflow prevention circuit 12 is connected, an output terminal 11b and an output terminal strip 11c are provided. The auxiliary capacitor 23 may be connected between the output terminals of the solar cell 11 as shown by the dotted line in the figure.

The timepiece movement 20 arranged on the back side of the light receiving section 10 has a chemical secondary battery 21 connected to the output terminal 11b and the output terminal piece 11c, and a pair of electrodes of the chemical secondary battery 21. A connected clock control circuit 22,
A clock drive unit 24 is provided. Clock control circuit 22
Has the same configuration as a normal battery clock, and does not include any additional functions for a clock with solar batteries.

FIG. 2 shows a specific example of the structure of the solar cell 11, and FIG.
FIG. 2B is a bottom view of the solar cell 11. Solar cell 1
1. A metal electrode layer, a semiconductor layer, an insulating layer, a wiring electrode layer, a light-transmitting sealing resin layer, and the like are laminated on the surface of an insulating base material 11A made of a synthetic resin film, a glass substrate, or the like. It is constituted by doing. Two semicircular light receiving regions 11B are formed on the surface of the solar cell 11, and a wiring region 11F for passing the wiring connected to the wiring electrode layer on the front surface is formed around the periphery of the solar cell 11 around the light receiving region 11B. Is provided.

In this solar cell 11, the insulating base material 1
By using 1A, a through hole is formed in the insulating base material 11A by laser processing or the like, and as shown in FIG. 2B, the insulating base material 11A is formed through the through hole.
1 connected to the metal electrode layer and the wiring electrode layer on the back surface of
1d and 11e are drawn out, an output terminal 11b formed of conductive rubber or the like is conductively connected to the wiring 11d, and protrudes on the back surface of the insulating base material 11A. Conventionally, four fan-shaped light receiving areas are divided and four power generating units having each light receiving area are connected in series. In the case of the present embodiment, as shown in FIG. Is divided into two light receiving regions 11B, and two power generating units are connected in series. Therefore, as described later, the generated voltage is low, but a large amount of current can be obtained.

FIG. 3 is a bottom view of the timepiece when the light receiving unit 10 and the timepiece movement 20 arranged inside the timepiece are connected as viewed from the back cover side of the timepiece. FIG. 4A shows the light receiving unit 10 and the timepiece movement. FIG. 4B is a schematic partial side sectional view showing a state in which the light receiving unit 10 and the timepiece movement 20 are connected to each other. In each of the above drawings, the detailed structure inside the timepiece movement 20 is omitted.

The timepiece movement 20 is provided with a terminal piece 20a having a spring property and connected to a built-in timepiece control circuit 22 (mounted on a circuit board in the movement as a timepiece IC). . This terminal strip 20a
Is mounted on a circuit board provided in the timepiece movement 20, and projects from the circuit board into a recess for incorporating a battery, and the recess accommodates the chemical secondary battery 21 described above. At this time, the terminal piece 20a is in contact with the positive electrode of the chemical secondary battery 21. The terminal piece 20a is exposed toward the light receiving unit 10 together with the positive electrode of the chemical secondary battery 21.

On the other hand, the light receiving unit 10 is provided with the solar cell 11
And a substrate receiving member 13 (corresponding to the above-mentioned holding member) made of a ring-shaped (or frame-shaped) synthetic resin or the like mounted on the outer peripheral portion so as to hold the solar cell 11, and the solar cell 11. A light-transmitting surface plate 14 disposed or adhered to the front side (the lower side in the figure). The light transmitting plate 14 may be a transparent plate made of glass, synthetic resin, or the like, but is formed of a translucent white plate or other translucent material as long as the power generation of the solar cell 11 is not reduced unnecessarily. May be.

Wiring 11 projecting from the back of solar cell 11
One end of the backflow prevention circuit 12 is electrically conductively bonded to the tip of e, and the other terminal of the backflow prevention circuit 12 is conductively bonded to the base of the output terminal piece 11c fixed on the back surface of the solar cell 11. Have been. The output terminal strip 11c has a rising portion configured to come into contact with the outer peripheral surface, which is the negative electrode of the chemical secondary battery 21, with spring pressure. The output terminal 11 b protruding from the back surface of the solar cell 11 is connected to the above-described terminal piece 20 that is in contact with the positive electrode of the chemical secondary battery 21.
a from below. Note that the output terminal 11b may be in direct contact with the positive electrode of the chemical secondary battery 21 avoiding the terminal piece 20a.

The backflow prevention circuit 12 is actually a diode element. This diode element may be mounted directly on the back surface of the solar cell 11 as described above, or may be mounted on an auxiliary circuit board attached to the solar cell. In any case, since the backflow prevention circuit 12 is attached to the solar cell, the backflow prevention circuit 12 can be integrally handled as a solar cell module, and can be easily assembled to a normal watch movement.

The timepiece movement 20 includes the dial receiving member 1.
By lightly pressing against the light receiving member 3, it engages with the engaging portion 13 a of the dial receiving ring 13 and is held by the light receiving portion 10. At this time, the output terminal 11b is in contact with the terminal piece 20a or the positive electrode of the chemical secondary battery 21, and the output terminal piece 11c is held in contact with the negative electrode of the chemical secondary battery 21.

In the present embodiment, the solar cell 11 is formed on the insulating base material 11A, but may be formed on a metal substrate such as stainless steel. In this case, an output can be drawn out to the back side by attaching an insulating substrate to the outer peripheral portion of the solar cell. Further, the solar cell 11 does not need to be completely fixed to another member,
It is sufficient if the insulating base material 11A is flexible such as a synthetic resin film or the like. However, if the insulating base material 11A is flexible such as a synthetic resin film, the insulating base material 11A is attached to the surface plate 14 or the surface of the watch movement 20. You may be comprised so that it may wear.

The chemical secondary battery 21 of the present embodiment is, specifically, a titanium lithium ion secondary battery. A titanium lithium ion secondary battery uses a lithium-manganese composite oxide (Li _X MnO _Y ) for a positive electrode, uses a lithium-titanium composite oxide (Li _X Ti _Y O ₄ ) for a negative electrode, and uses a lithium salt as an electrolyte. An organic solvent was used. FIG. 5 shows the discharge characteristics of the titanium lithium ion secondary batteries A and B (A is MT621 and B is MT920 manufactured by Matsushita Battery) used in the present embodiment. This characteristic is not limited to a titanium lithium ion secondary battery, but is a characteristic common to various chemical secondary batteries using an ion exchange action.
Chemical secondary batteries are shown as capacitors C, D, E (C and E are polyacene capacitors, D is a gold capacitor)
Unlike the case where the voltage and the storage capacity are proportional to each other, the output voltage can be maintained within a relatively narrow fluctuation range in most of the discharging process, and as a result, in the normal use region of the charged state. The fluctuation amount of the output voltage can be suppressed low.

The chemical secondary battery used in the present embodiment has a relatively small flat region S which falls within the output voltage fluctuation range X.
_A and S _B. These flat regions S _A and S _B do not have to be completely flat output voltage characteristics in the discharge characteristics, but are portions having characteristics slightly deviating from the linear discharge characteristics such as the above-mentioned capacitors. . However, a very desirable definition of the flat region S as the present embodiment is as follows.
For example, it is a region corresponding to a discharge capacity of 70% to 80% or more of the total discharge capacity (maximum storage capacity) of the chemical secondary battery, and a fluctuation range X with respect to the output voltage value in the flat region S.
Is in a range where the ratio of the widths is 30% or less. Here, in the case of the secondary battery of this embodiment shown in the figure, the output voltage value is about 1.15 to 1.4 V in the fluctuation range X, and the width of the fluctuation range X is about 0.25 V Therefore, the above ratio is about 17 to 22%.

The practical range of the characteristics of the chemical secondary battery is wider than the above-mentioned very desirable range, and the ratio of the fluctuation width of the fluctuation range X to the output voltage value is 50% or less. The ratio of the discharge capacity corresponding to the flat region S to the capacity may be 50% or more. Since the fluctuation range X is higher than the minimum operating voltage Y of the timepiece movement 20, in the present embodiment, there is no problem in driving the timepiece movement in normal times. Further, in the chemical secondary battery, a region where an output voltage lower than the discharge voltage value in the flat region can be obtained is extremely small as compared with the whole region. Therefore, even if the boosting circuit is not provided, no particularly serious problem occurs.

The rated voltage of the above-mentioned chemical secondary battery used in the present embodiment is about 1.5 V. When the rated voltage is exceeded, the battery is slightly deteriorated due to electrolysis of the positive electrode or decomposition of the electrolytic solution. Be faster. If the maximum allowable applied voltage exceeds 2.6 V, the decomposition reaction of the positive electrode sharply increases, and the deterioration of the electrolytic solution also proceeds rapidly.

Next, FIG. 6 shows the initial charging characteristics of the above-mentioned chemical secondary battery when charging is started at a constant current from a completely discharged state. Here, F is a charge current of 0.1
mA, G is 0.5 mA, H is 1.0 mA, I is 2.0 m
The characteristics at the time of A are shown. This graph shows a case where charging with a constant current is stopped 10 minutes after the start of charging. Incidentally, the voltage value after the lapse of 10 minutes shows a value close to the original discharge voltage of the chemical secondary battery. This chemical secondary battery has a property that the output voltage temporarily increases at the start of charging, and as shown in FIG. 6, the higher the charging current value, the greater the temporary increase in the output voltage. .
Therefore, by using this kind of chemical secondary battery, the output voltage is quickly increased to be higher than the operable voltage Y of the timepiece movement at the initial time when charging is started when the chemical secondary battery is in a completely discharged state. Therefore, it is not necessary to provide a start time reducing means such as an immediate start circuit.

FIG. 7 shows the relationship between the voltage and the current at the time of power generation of the solar cell 11 of the present embodiment in which the number of power generation units connected in series is two, and the conventional solar cell 81 of four stages. It shows the IV characteristics. However, this IV characteristic is measured under an illuminance of 700 lux, which is slightly darker than in a room, and actually generated power becomes larger in the daytime. As can be seen from this graph, in the present embodiment, the maximum value of the voltage is reduced to about 1.4 V by reducing the number of stages of the power generation unit 11a of the solar cell 11 to two, but the current is lower than that of the related art. Can be obtained about twice. Therefore, although the charging voltage is lower than before, the charging current can be increased, so that the effect of increasing the output voltage at the start of charging shown in FIG. 6 can be enhanced.

In the present embodiment, a charging voltage of 1.4 V at the maximum can be ensured even if the output voltage of the solar cell 11 is at most about 1.6 V and the voltage drop in the backflow prevention circuit 12 is about 0.2 V. On the other hand, according to the characteristics of the chemical secondary battery 21, most of the charging capacity can be charged by charging at 1.4V. The maximum charging voltage of 1.4 V is the maximum allowable applied voltage of the chemical secondary battery 21 of 2.6 V.
Overcharge prevention circuit becomes unnecessary, and since the maximum charging voltage is lower than the rated voltage of 1.5 V, the decomposition reaction of the positive electrode and the electrolyte in the secondary battery is suppressed to be low. Degradation can be reduced. Further, since the maximum charging voltage is equal to or lower than the rated voltage, it is not necessary to use a member made of aluminum or special stainless steel on the inner surface of the positive electrode of the secondary battery in order to suppress the decomposition of the positive electrode. As the voltage can be set low, the degree of freedom in the configuration of the secondary battery is increased,
The manufacturing cost of the secondary battery can be reduced, and the selection range of the secondary battery can be expanded.

Here, the difference between the case where solar cells are connected in series in two stages as described above and the case where solar cells are connected in series in three stages will be described. When connected in two stages, the maximum generated voltage is about 1.
6V and the maximum charging voltage are about 1.4V as described above, whereas when connected in three stages, the maximum power generation voltage is about 2.
4V, the maximum charging voltage is about 2.2V. Therefore,
When connected in two stages, the maximum charging voltage is lower than the rated voltage, but when connected in three stages, the maximum charging voltage exceeds the rated voltage, and the deterioration of the secondary battery is accelerated. On the other hand, when connected in two stages, the generated current is about 1.10 compared to when connected in three stages with the same light receiving area.
Since it is five times, the charging current can be increased, so that the charging efficiency is increased and the time for starting the watch from the discharging state is also shortened.

As described above, in the present embodiment, an electronic timepiece with a solar cell can be formed only by attaching the light receiving section 10 to a normal timepiece movement 20, and the conventional electronic timepiece with a solar cell can be formed. Since functions such as an overcharge prevention circuit, an immediate start circuit (start time reducing means), and a booster circuit, which are required for a dedicated circuit, are not required, manufacturing costs can be significantly reduced. Therefore, it is possible to supply an inexpensive electronic timepiece with a solar cell to the market, and it is not necessary to replace the battery, and it is possible to spread the electronic timepiece without disposing of a waste battery. Play.

[0042]

As described above, according to the present invention, when constructing a timepiece with a solar cell, it is not necessary to separately manufacture a timepiece movement having a dedicated circuit as in the prior art. It is not necessary to provide some components (such as an immediate start circuit, a boost circuit, and an overcharge prevention circuit), and a general-purpose watch movement can be used as it is, so that the manufacturing cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a configuration of a power supply system in an embodiment of an electronic timepiece with a solar cell according to the present invention.

FIG. 2 is a plan view (a) and a bottom view (b) showing the structure of the solar cell of the embodiment.

FIG. 3 is a bottom view of an assembly of the light receiving unit and the timepiece movement in the embodiment.

FIG. 4 is a partial side sectional view schematically showing a disassembled state (a) and an assembled state (b) of the light receiving unit and the timepiece movement in the embodiment.

FIG. 5 is a graph showing discharge characteristics of the chemical secondary battery in the same embodiment.

FIG. 6 is a graph showing initial charging start characteristics of the chemical secondary battery in the same embodiment.

FIG. 7 is a graph showing IV characteristics of the solar cell in the same embodiment.

FIG. 8 is a schematic configuration block diagram showing a configuration of a power supply system of a conventional electronic timepiece with a solar cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Light-receiving part 11 Solar cell 11a Power generation part 11b Output terminal 11c Output terminal piece 12 Backflow prevention circuit (diode) 20 Clock movement 20a Terminal piece 21 Chemical secondary battery 22 Clock control circuit 23 Auxiliary capacitor 24 Clock drive part

Claims (9)

[Claims] 1. A watch movement having a function required to operate by receiving power supply from a primary battery,
Equipped with a rechargeable power storage means in place of the primary battery, having a maximum power generation voltage equal to or higher than the minimum operation voltage of the timepiece movement and having an output terminal connected to the power storage means, the power generation unit in two stages A solar cell having a structure connected in series, and a backflow prevention circuit connected between the solar cell and the power storage means are provided, and the power storage means is a secondary battery having a flat region in discharge voltage characteristics. An electronic timepiece with a solar cell, wherein a maximum charging voltage value to the power storage means corresponding to the maximum power generation voltage is equal to or less than a rated voltage value of the power storage means. 2. The device according to claim 1, further comprising a structure in which the solar battery and a solar cell module including the backflow prevention circuit are connected to the power storage means and the timepiece movement. Electronic clock with solar cells. 3. A solar battery, a power storage means for storing power generated by the solar cell, and a clock movement operated by power supplied from the solar cell or the power storage means, wherein the power storage means and the clock movement On the other hand, the solar system has a structure in which a solar cell module having a solar cell, a backflow prevention circuit connected to the solar cell, and an output terminal connectable to the power storage means is connected. Electronic clock with battery. 4. The solar cell module according to claim 2, further comprising a holding member for holding a component of the solar cell module, and the holding member is configured to be engageable with the timepiece movement. An electronic timepiece with a solar cell, characterized in that: 5. One of claims 2 to 4
In the paragraph, the solar cell is constituted by a laminated structure on an insulating substrate, and the output terminal is connected to a conductor drawn out through a through hole formed in the insulating substrate and provided on a back surface of the insulating substrate. An electronic timepiece with a solar cell, comprising: 6. One of claims 3 to 5
9. The electronic timepiece with a solar cell according to item 1, wherein the power storage means is a secondary battery having a flat region in discharge voltage characteristics. 7. The electronic timepiece with a solar cell according to claim 6, wherein a maximum generated voltage of the solar cell is substantially equal to a voltage value of the flat region in the secondary battery. 8. The electronic device with a solar cell according to claim 6, wherein the secondary battery has a characteristic that an output voltage temporarily increases at the time of initial start in a low charge state. clock. 9. Any one of claims 6 to 8
In the paragraph, the secondary battery is a lithium ion secondary battery, wherein the electronic timepiece with a solar cell is provided.