JP2001183620A - Solar cell type liquid crystal device - Google Patents

Abstract

(57) [Summary] [Problem] In a solar cell type liquid crystal device, a coin-type primary battery was used as a power source in order to reduce the size and weight, but there is an inconvenience that the battery needs to be replaced. In addition, there is a difficulty in positioning so as not to cause poor contact of liquid crystal when assembling a solar cell type liquid crystal device. SOLUTION: In order to solve these problems, a solar cell 11 is used as a power supply in a circuit including a booster circuit 20, or a solar cell 11 and a primary cell, or a solar cell 11 and a secondary cell are used as a power supply. By combining them, they can be used semi-permanently, eliminating the inconvenience of replacing batteries. Also, by using a liquid crystal fixed silicone rubber which also has a switch, positioning of the liquid crystal and connection of terminals can be facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell type liquid crystal device using a solar cell as a power source.

[0002]

2. Description of the Related Art Conventionally, as a solar cell type liquid crystal device, a simple portable solar cell type calculator is known. Since the liquid crystal display unit is small and does not require a large current and a large voltage, these circuits use, for example, a solar cell of 29 mm × 11 mm size (power generation capacity is 1.5 V, 10 μA), and simply use the electric power. Was operated and the liquid crystal display was displayed.

On the other hand, a portable liquid crystal game device, which is one of the portable devices, uses a coin-type lithium primary battery, a dry battery, or the like as a power source in order to reduce the size and weight. The biggest drawback of using this primary battery can be said to be battery replacement. Although the battery duration has been greatly increased compared to the past due to the recent reduction in power consumption of semiconductor devices, on the other hand, due to the increase in the amount of information, the complexity of functions, and the acceleration of arithmetic processing, etc.
It is a fact that it is difficult to save power above a certain level. Therefore, the user must replace the battery as a consumable every time, and the user is inconvenienced while maintaining the maintenance cost.

In a portable liquid crystal game device, as long as a primary battery is used, a replacement operation by a user is inevitable. An easy solution is to use a rechargeable rechargeable battery, but this method simply replaces the battery replacement with charging using an AC adapter or charger. Convenience is not always improved.

As a means for reducing the battery replacement, it is conceivable to use the above-described solar cell as described in Japanese Patent Application Laid-Open No. 5-261180.

[0006]

However, the configuration described in Japanese Patent Application Laid-Open No. 5-261180 has a problem that it is driven only by the electric power generated by the solar cell, so that it can be used only for equipment with low power consumption. .

SUMMARY OF THE INVENTION The present invention solves this first problem, and is capable of forming a self-contained power supply or increasing the duration thereof, such as a solar cell type liquid crystal device such as a portable liquid crystal game device. The purpose is to provide equipment.

Further, in a liquid crystal device comprising a liquid crystal, a conductive zebra rubber, a liquid crystal control circuit board, and a housing case for fixing them, in order to accurately conduct the liquid crystal, the conductive zebra rubber and the control circuit board, the housing case is required. Each part must be fixed in the correct position. However, the liquid crystal may not be displayed correctly due to a dimensional error of the case or the component itself.

The present invention solves the second problem, and since the positioning and fixing of the case case and the liquid crystal can be easily performed, it is possible to prevent poor contact between the zebra rubber and the liquid crystal control circuit board. With the goal.

[0010]

According to one aspect of the present invention, a solar cell as a power source is provided.
A step-up circuit for operating only the voltage of the solar cell as a power supply to convert the voltage to a device operating voltage, an operation unit for performing various operations by a user, a control circuit for performing control in accordance with an operation in the operation unit, And a display section made of liquid crystal for performing display in accordance with an output from the control circuit. On this occasion,
A solar cell that generates power by outdoor light or indoor light under fluorescent light or electric light and a booster circuit that operates using only the solar cell as a power source may cover all of the driving power source of the solar cell type liquid crystal device, or the solar cell It is also conceivable to additionally provide a rechargeable secondary battery, electric double layer capacitor, primary battery, or the like as a power source other than the above.

As a result, it is possible to provide a solar cell type liquid crystal device capable of reliably supplying necessary electric power to the drive circuit.

According to a second aspect of the present invention, there is provided a housing case, a liquid crystal control circuit board accommodated in the housing case for controlling a liquid crystal display, and a conductive portion of the liquid crystal control circuit board. A conductive zebra rubber, a liquid crystal that performs display according to the output of the liquid crystal control circuit board through the conductive zebra rubber, and a liquid crystal fixed frame that regulates three surfaces of the liquid crystal;
The remaining liquid crystal is stored at a predetermined position of the liquid crystal fixing frame.
And a liquid crystal positioning rubber for suppressing and fixing the surface by elasticity.

Thus, when the liquid crystal is assembled into the housing case, it is possible to prevent a defect in conduction with the liquid crystal control circuit board due to a shift in the fixed position, thereby preventing erroneous display of the liquid crystal dots.

Further, by making the liquid crystal positioning rubber and the conductive zebra rubber conductive and making the liquid crystal positioning rubber also have a switch function, the number of parts can be reduced, space can be saved, and
Cost reduction can be achieved.

If the solar cell is a CdS / CdTe solar cell having good sensitivity to both outdoor light and indoor light, a solar cell type liquid crystal device can be used both indoors and outdoors.

[0016]

Embodiments of the present invention will be described below.

1 and 2 show the configuration of a solar cell and a solar cell type liquid crystal device according to an embodiment of the present invention. By using an indoor solar cell suitable for indoor light such as a fluorescent lamp or a light bulb, a device that operates indoors, in a car, on a desk, or the like can be realized as the solar cell 1. The solar cell 1 may be an outdoor solar cell suitable for the wavelength and illuminance of outdoor light. For example,
CdS / CdT with good sensitivity to both outdoor light and indoor light
An e-type solar cell is preferably used.

In the case of using an indoor solar cell for use under the indoor conditions described above, it is desirable that the driving current of the drive circuit 2 is not more than the electric power generated by the indoor solar cell. As a result, the effect of suppressing the consumption of the battery becomes remarkable, and in particular, when the device is driven only by the solar cell, the operation of the device becomes unstable because the generated current changes depending on the intensity of light applied to the solar cell. It is possible to prevent that.

In addition, by constituting a power supply with a solar battery and a secondary battery, it is possible to make battery replacement almost unnecessary. By the way, the combination of a solar cell and a secondary battery is already a well-known fact in a solar cell device, but when the present invention is applied to a device of a portable size as in the present invention, there is a practical limitation in the embodiment. Occurs.
For example, it is not very suitable to combine the above-mentioned indoor solar cell with an existing nickel-cadmium battery or lead-acid battery because of its self-discharge characteristics. Since the amount of electricity that can be generated by a solar cell indoors in the current technology is on the order of microamps, a lithium secondary battery with low self-discharge or an electric double-layer capacitor capable of rapid charging is optimal.

By the way, as shown in FIG. 3, when combined with a lithium secondary battery or an electric double layer capacitor, if the generated current of the solar cell is sufficiently larger than the consumption current of the drive circuit, the secondary battery is protected from overcharge. It is better to configure an overcharging control means. Further, when the lithium secondary battery is over-discharged, the charge / discharge cycle life is deteriorated. Therefore, if the current consumption of the drive circuit exceeds the power generation current of the solar cell, it is better to configure over-discharge prevention control means.

Next, by using only the power generated by the solar cell as a power source and mounting a booster circuit for converting the operating voltage to a different voltage, the power of the solar cell having a low operating voltage is converted to the charging voltage of the secondary battery. To charge the battery or convert it to the discharge voltage of the primary battery or the operating voltage of the drive circuit shown in 2. By this effect, the voltage of the solar cell itself can be reduced, so that the number of serially connected cells of the solar cell can be reduced. Thereby, a smaller solar cell can be used. In an indoor solar cell, both amorphous and CdS / CdTe solar cells have an operating voltage of about 0.4 V per single cell under indoor light of 200 lux, and an operating voltage obtained by series connection of four cells is 1.5 to The current that can be generated by a solar cell having a size of 1.6 V, for example, a 29 mm × 11 mm size used in an applied device such as a calculator is about 10 μA at 1.5 V. A solar cell of this size is small enough for a portable device and considered practical.
For example, in order to obtain an operating voltage of 3 V using only this solar cell, it is necessary to use two solar cells in series or to use eight solar cells. Increasing the number of cells in series in a solar cell having a fixed area increases the dead space on the pattern required for series connection, and accordingly reduces the effective area contributing to power generation and lowers power generation efficiency. In addition, since the output current of the series connection is regulated by the impedance of the single cell, it is easily affected by variations in cells.

According to the booster circuit of the present invention, even when it is difficult to increase the number of series connections such as a solar cell having a small area, or when it is difficult to use a plurality of solar cells themselves, it is possible to drive using only the power of the solar cells themselves. Generating circuit voltage,
It is possible to charge the battery by converting it to a voltage optimal for charging the secondary battery.

According to the second and third aspects of the present invention, the positioning and fixing of the housing case and the liquid crystal of the device can be easily realized. 2. Description of the Related Art Conventionally, as a method for conducting liquid crystal and a liquid crystal control circuit board in a small portable device or the like, there has been known a method in which the liquid crystal is pressed into contact with each other via a conductive zebra rubber. The advantage of this method is that the structure is simple and inexpensive.However, the disadvantage is that the contact between the liquid crystal control circuit board and the conductive zebra rubber due to slight displacement and the displacement of the liquid crystal and the conductive zebra rubber during pressure contact. There is a problem that tends to cause defects. As a solution to this, a groove for fixing the position of the conductive zebra rubber is formed by resin, or the liquid crystal is fixed by a resin frame, etc. However, when it becomes large, there are problems that it becomes difficult to fix to the regulation frame and that the displacement cannot be absorbed after all. According to the present invention, the configuration is such that the end face of the liquid crystal is pressed against the end face (liquid crystal positioning rubber) of the rubber molded product, so that a dimensional error of the liquid crystal can be absorbed and stable fixing can be achieved. The rubber molded product may be formed of, for example, zebra rubber and have a switch function. In this manner, the liquid crystal position adjustment function and the switch function can be realized at the same time.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. First, an embodiment according to the first aspect of the present invention will be described with reference to FIGS. 1 to 7, and embodiments according to the second and third aspects of the invention will be described with reference to FIG. 8.

1 to 3 are power supply circuit diagrams of a solar cell type liquid crystal device.

The power supply circuit of the solar battery type liquid crystal device is a solar battery 1, a driving circuit 2, a primary battery or a secondary battery, a backflow prevention diode 4, an overcharge prevention means 7, an overdischarge prevention means 9.
It is composed of As the solar cell 1, an outdoor solar cell suitable for power generation under outdoor light may be used in addition to an indoor solar cell suitable for power generation under a fluorescent lamp or a light bulb. When the secondary battery 3 is mounted, the electricity generated by the solar battery is charged to the secondary battery 3 via the backflow prevention diode 4, and in the case of the primary battery 3, the electricity is separated via the backflow prevention diode 4, The electricity output from both is mixed at point a and supplied to the drive circuit 2.

In the present embodiment, the primary battery and the secondary battery are used together as described above. As described above, when the indoor solar cell and the outdoor solar cell are used, the use effect of the used battery itself differs. That's why. When using indoor solar cells, the current that can be generated is as small as μA,
Even if a secondary battery is used in combination, the proportion that can contribute to charging is very small, and it may be difficult to design to cover all of the load consumption. Therefore, in such a case, it is more practical to use the battery together with the primary battery so as to prevent the consumption of the primary battery at all.

On the other hand, in a solar cell for outdoor use, a sufficient power generation current can be obtained, so that it is more practical to charge excess electricity exceeding the load consumption, and it is effective because battery replacement is hardly required. Furthermore, a configuration in which the primary battery and the secondary battery are not used and the solar cell 1 alone is directly connected to the drive circuit 2 may be used. In this case, since the operating point of the solar cell fluctuates freely according to the load due to the fluctuation of the current consumption of the load, a smoothing capacitor 6 may be connected in parallel to absorb the fluctuation and smooth the voltage.

If the open voltage of the solar cell is sufficiently high, the driving circuit 2 may be damaged. Therefore, a zener diode 5 may be connected in parallel to prevent application of a voltage higher than a certain value. Note that the Zener diode 5 has the same effect even when a primary battery is used in combination.

Next, the embodiment shown in FIG. 3 will be described. If the current supplied from the solar cell 1 exceeds the current consumed by the drive circuit 2, the secondary battery 3 may be overcharged. In the present embodiment, the overcharge prevention means 7 for detecting the voltage of the secondary battery and stopping the charging if overcharged, and charging ON, OF
An F switch means 8 is provided. As a means of a switch for charging ON / OFF, an element such as a transistor, an FET, or a semiconductor relay may be used. The circuit inside the overcharge prevention means 7 may be configured using a comparator or an IC dedicated to voltage detection as a means for detecting the battery voltage. In addition,
The overcharge prevention means 7 may be formed inside the drive circuit 2 and may be controlled to increase the current consumption of the drive circuit 2 with respect to overcharge. For example, a method of controlling the microcomputer in the drive circuit and increasing the current consumption of the microcomputer itself by software is possible. According to this method, it is possible to control the charging of the secondary battery without increasing the number of components such as the charging ON / OFF switch 8.

Next, an embodiment for overdischarge of the secondary battery will be described with reference to FIG. Overdischarging of the battery is a problem in the case of a secondary battery, and if a state in which the amount of load consumption current is larger than the amount of charge from the solar battery continues, the secondary battery is overdischarged. Generally, a secondary battery is vulnerable to overdischarge, and the overdischarge may significantly shorten the charge / discharge cycle life. In this embodiment, the overdischarge prevention means 9 and the discharge O
An N / OFF switch means 10 is provided. The overdischarge prevention means 9 may be configured as a circuit using a comparator or an IC dedicated to voltage detection as a means for detecting the battery voltage. Note that the overdischarge prevention means 9 may be formed inside the drive circuit 2, and may be controlled so that the current consumption of the drive circuit 2 is reduced or completely eliminated with respect to overdischarge. For example, a method in which the microcomputer is controlled by a microcomputer in the drive circuit and the microcomputer itself is put into a sleep or halt state by software to reduce current consumption is possible. According to this method, the discharge control of the secondary battery can be performed without increasing the components such as the discharge ON / OFF switch 10.

Next, a booster circuit for converting the voltage of the solar cell into a device operating voltage will be described with reference to FIGS.

FIG. 4 is a booster circuit according to the present embodiment, FIG. 5 is a circuit characteristic, FIG. 6 is a diagram of a solar cell operating point, and FIG. 7 is a state transition diagram. This booster circuit includes a solar cell 11, an oscillation circuit 12,
PchMOS transistor 13 for switching, Nc
hMOS transistor 14, charging capacitor 15,
Smoothing capacitor 16, backflow prevention diodes 17, 18
The oscillation circuit 12 has an oscillation control terminal b. According to the present embodiment, the oscillation circuit 12, the switching NchMOS transistor 14, and the backflow prevention diode 17 are all connected to the solar cell 11, so that the power required for the oscillating operation and the boosting itself can be covered only by the solar cell. The oscillation circuit 12 is a MOS type semiconductor element or F
You may comprise by ET. However, if the starting voltage is insufficient for the oscillation circuit 12 to oscillate, the oscillation circuit power supply terminal d and the boost output terminal C are connected so that power is fed back from the secondary battery 19 or the primary battery connected to the boost output terminal C. A circuit configuration may be used. At this time, the solar cell output terminal e and the oscillation circuit power supply terminal d are disconnected. If the operating voltage and the generated current of the solar cell 11 are more than the operating power of the oscillation circuit 12,
This power feedback circuit is unnecessary, and a completely independent power supply source that operates only with solar cells can be realized. According to the circuit of the present embodiment, it is possible to obtain about double voltage output of electricity generated by the solar cell. For example, if a 1.5 V indoor solar cell is connected to the booster circuit 20, about 2.6 V to 2. It is possible to obtain a boosted output of 8V. This makes it possible to charge a lithium secondary battery, an electric double layer capacitor, and the like with a solar cell composed of four cells for 1.5 V, and a small-sized solar cell can be used.

FIG. 5 shows circuit characteristics when the input is a constant current power supply and the output is swept by a constant current sink power supply. The parameter is the suction current value. As can be seen from this characteristic, when the input voltage is 1.55 V, the input current is only 10
It can be seen that the device operates at μA and can be converted to 3 V with an efficiency of 60 to 80%.

Next, the operation of the circuit in this embodiment will be described. When the charging capacitor 15 is discharged in the initial state, the oscillation circuit 12 operates, and when the NchMOS transistor 14 is turned on, the charging capacitor 15 is charged through the backflow prevention diode 17. At this time, the operating point of the solar cell is such that the operating voltage is instantaneously lowered to the point as shown in FIG. 6, and as the charging capacitor 15 is charged, the voltage shifts from the point to the point again and rises.
Next, when the PchMOS transistor 13 is turned on, the negative side of the charging capacitor 15 is added by the operating voltage at the point of the solar cell, and the backflow prevention diode 1 is added.
8 is output. FIG. 7 shows this state transition. In the operation of this circuit, the oscillation circuit 12 must be able to continue operation even when the operating voltage of the solar cell is at a point.
Therefore, it is preferable that the oscillation circuit 12 be constituted by a C-MOS device or the like. Alternatively, as described above, the operation of the oscillation circuit 12 may be stabilized by supplying power from the secondary battery or the primary battery.

By providing the oscillation control terminal b, the operation of the boosting circuit 20 can be controlled by a microcomputer or the like. Further, by connecting a plurality of stages of the entire booster circuit 20 in series, it is possible to boost the voltage by a factor of 2N.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, a liquid crystal 21 is provided.
It comprises a conductive zebra rubber 22, a liquid crystal control circuit board 23, a liquid crystal positioning rubber 24, and a liquid crystal fixing frame 25. By the way, a structural problem according to the present embodiment is a defective lighting of the liquid crystal due to a dimensional deviation of the components. In particular, such a problem occurs because the liquid crystal 21 is a glass material and thus has no stop holes or the like and is a component that is difficult to fix.

According to the present embodiment, the thickness of the conductive zebra rubber 22 in the electrode direction (Y direction) is sufficient for the displacement of the liquid crystal in the Y direction due to the dimensional error of the fixed frame width I of the liquid crystal fixed frame 25. It is absorbed by making it larger. On the other hand, in the X direction, the distance between the electrodes of the conductive zebra rubber 22 is generally as small as 0.4 to 0.6 mm. It is difficult to make the fixing frame 25 a housing case that matches the entire circumference of the liquid crystal in terms of accuracy. Therefore, the three side surfaces of the liquid crystal fixing frame 25 are regulated by the liquid crystal fixing frame 25, that is, the liquid crystal 21 is fixed so that the liquid crystal end face g is applied to the liquid crystal fixing frame end face f, and at the same time, the liquid crystal positioning rubber 24 is fixed to the housing case 25. It is configured to be attached to the pocket of. As a result, the liquid crystal 21 is suppressed and fixed more closely to the liquid crystal fixing frame end face f by the elasticity of the liquid crystal positioning rubber 24, and the position in the X-axis direction can be completely stabilized. The defective lighting of the liquid crystal due to the displacement of the liquid crystal and each component can be eliminated.

The liquid crystal positioning rubber 24 may be made of a conductive zebra rubber and a carbon electrode may be buried in the direction of the circuit board surface so that the liquid crystal positioning rubber 24 also has a switching function, thereby reducing the number of components. Further, as the material of the liquid crystal positioning rubber 24, elastic silicon rubber or urethane may be used in addition to zebra rubber.

FIG. 9 is an external view showing a solar cell type liquid crystal device according to an embodiment of the present invention.

[0041]

According to the present invention, a liquid crystal device is provided with a solar cell and a booster circuit that operates using only the solar cell as a power source, and is driven by a power source using only the solar cell. A solar cell type liquid crystal device which does not require replacement can be provided.

Further, when the solar cell type liquid crystal device is made portable, the size of the solar cell is limited due to its small space. Therefore, the number of solar cells in series is small,
Thus, there is also an effect that a solar cell having a small voltage can be driven by boosting the voltage by a boosting circuit that operates using only the solar cell as a power supply.

In terms of structure, the adoption of the liquid crystal positioning rubber having the function of a switch also has an effect that a solar cell type liquid crystal device can be easily assembled.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a solar cell type liquid crystal device.

FIG. 2 is another circuit diagram of a solar cell type liquid crystal device.

FIG. 3 is another circuit diagram of a solar cell type liquid crystal device.

FIG. 4 is a booster circuit diagram

FIG. 5 is a circuit characteristic diagram of a booster circuit.

FIG. 6 is a diagram of an operating point of a solar cell.

FIG. 7 is a state transition diagram of a solar cell.

FIG. 8 is a diagram showing a method for fixing a liquid crystal.

FIG. 9 is an external view of a solar cell type liquid crystal device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solar cell 2 Drive circuit 3 Primary battery or secondary battery 4 Backflow prevention diode 5 Zener diode 6 Smoothing capacitor 7 Overcharge prevention means 8 Charge ON / OFF switch means 9 Overdischarge prevention means 10 Discharge ON / OFF switch means 11 Solar cell 12 Oscillation circuit 13 Pchmos transistor 14 NchMos transistor 15 Charging capacitor 16 Smoothing capacitor 17 Backflow prevention diode 18 Backflow prevention diode 19 Secondary battery 20 Boost circuit 21 Liquid crystal 22 Conductive zebra rubber 23 Liquid crystal control circuit board 24 Liquid crystal positioning rubber 25 Liquid crystal Fixed frame a Mixing point b Oscillation control terminal c Boost output terminal d Oscillator circuit power terminal e Solar cell output terminal f Liquid crystal fixed frame end face g Liquid crystal end face h Liquid crystal end face i Fixed frame width 26 Solar cell 27 Liquid crystal 8 button switch

Continued on the front page (72) Inventor Shin Arakawa 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F term (reference) 2H093 NC07 NC50 NC62 ND48 ND60 5F051 BA17 JA17 KA05

Claims (4)

[Claims] 1. A solar cell serving as a power supply, a booster circuit for operating only the voltage of the solar cell as a power supply to convert the voltage to a device operating voltage, an operation unit for a user to perform various operations, and a booster circuit A solar cell type liquid crystal, comprising: a driving circuit that receives power supply and performs drive control according to an operation in the operation unit; and a display unit including a liquid crystal that performs display according to an output from the driving circuit. machine. 2. A housing case, a liquid crystal control circuit board accommodated in the housing case for controlling liquid crystal display, a conductive zebra rubber disposed in a conductive portion of the liquid crystal control circuit board, and A liquid crystal for performing display according to the output of the liquid crystal control circuit board through zebra rubber;
A solar cell type liquid crystal device comprising: a liquid crystal fixing frame for regulating a surface; and a liquid crystal positioning rubber which is housed in a predetermined position of the liquid crystal fixing frame and elastically suppresses and fixes one side surface of the remaining liquid crystal. 3. The solar cell type liquid crystal device according to claim 2, wherein the liquid crystal positioning rubber and the conductive zebra rubber are electrically connected, and the liquid crystal positioning rubber has a switching function. 4. The solar cell type liquid crystal device according to claim 1, wherein the solar cell is a CdS / CdTe solar cell having good sensitivity to both outdoor light and indoor light.