JPH09292851A - Solar battery type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device for storing power from a solar battery on an accumulator and driving a display by the discharge power from the accumulator at night, capable of effective power accumulation and driving the display. SOLUTION: Generated power of a solar battery 10 is rectified by means of a rectifier 14, the rectified voltage is converted into a different voltage by means of a DC converter 12, the converted power is accumulated in an accumulator 18 being a capacitor, the discharge voltage of the accumulator 18 is variably controlled by means of a second DC converter 20 when necessary such as at night, and the quantity of power supply to a display 24 can be adjusted according to the accumulated quantity of the accumulator 18 to expand the display time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device in which an electromotive force of a solar cell is stored in a battery and a display device is driven by using the stored power.

[0002]

2. Description of the Related Art Conventionally, an LED (light emitting diode) has been used in a display device such as an electric road indicator, an electric signboard or a gate light.
Is known.

Generally, a display device using a solar cell is
The power generated by the solar cell is stored in a storage battery during the day, and the power is taken out at night to be used as a display power source. FIG. 4 shows a circuit configuration example of this type of display device.

In FIG. 4, the electric power generated by the solar cell 1 is stored in the storage battery 3 via the rectifier 2. L at night
The drive control signal from the ED drive control circuit 4 is transmitted to the transistor 7
When turned on, the transistor 7 turns on and the LED
A drive current flows to the group 5 via the load resistor 6, and the LED group 5
Lights up.

[0005]

In the conventional display device described above, as shown in FIG. 5, the amount of power generated by the solar cell is sufficient in fine weather, but insufficient in bad weather. Therefore, in order to obtain the required brightness, it is necessary to employ a storage battery having a sufficient capacity in consideration of the power generation amount in bad weather. Therefore, in the related art, as shown in FIG. 6, several times or more (for example, 30
A storage battery having a capacity capable of storing about twice as much power (for 30 days) is used.

[0006] In fine weather (including light cloudiness), the amount of power generated by the solar cell exceeds the amount of power required for one night, so the daily power storage balance of the power storage site increases, and the amount of power storage gradually increases. In bad weather such as full-scale cloudy weather, rainy weather or snowy days, the amount of stored electricity will be less than the required amount of electricity overnight,
It is designed to cover this shortage with the discharge power from the storage battery. The reason for such a configuration is that the solar cell itself is expensive, and therefore the smallest possible solar cell is used efficiently to obtain the necessary electric power. As a storage battery, a chemical secondary battery or the like having a large capacity and a low price is often used.

However, the chemical storage battery has a short life, and the number of times of charge and discharge is about several hundred times. Further, the chemical storage battery does not have good performance at low temperatures, and there is a case where the operating temperature is limited or an extremely small current is allowed. Therefore,
In a low temperature area, sufficient electricity could not be stored and it was difficult to spread.

An object of the present invention is to provide a display device in which a small solar cell and a small capacitor (capacitor) can efficiently store and discharge efficiently to drive the display stably.

[0009]

According to a first aspect of the present invention, there is provided a solar cell, a rectifier for rectifying power generated by the solar cell, and a first DC converter for performing voltage conversion of the rectified power. A power storage device that stores the voltage-converted power, a display device that emits light by receiving the discharge power supplied from the power storage device, and a second DC converter that performs the voltage conversion of the discharge power supplied to the display device. It is configured with.

Here, in a specific mode, the electric storage device has a storage capacity that is at least four times as much as the electric power required for one night, and can display for 6 hours at an illuminance of 10,000 Lx as the capacity of the solar cell. It is preferable that the electric storage device can supply a possible amount of electric power.

According to the first aspect of the present invention, the storage battery having a short life and having a problem in storing electricity at a low temperature is used as a storage battery (for example, an electric double layer type capacitor).
The storage battery has a long life because it does not involve a chemical reaction like a storage battery such as a conventional chemical secondary battery, and can be used even at low temperatures, and the influence of weather can be eliminated as much as possible. However, since a large capacity is required to enable storage of the same amount of electric power as a conventional storage battery, it is preferable to set the storage capacity to at least 1.5 to 4 times the required amount of power for one night.
In addition, it is preferable to combine a solar cell because it has sufficient power generation capacity even in bad weather. Further, since the first DC converter is capable of converting and adjusting the voltage generated by the solar cell, it is possible to store electricity according to the weather and improve the utilization efficiency of the solar cell. Can be converted. In the past, when electricity was stored in a display element from a storage battery, the electricity generated by the solar cell was directly driven by the battery voltage or constant current drive only through the rectifier. The efficiency is low if the conventional method is used because the voltage changes in accordance with the above. Therefore, in the present invention, by controlling the voltage and current supplied to the display device according to the remaining power amount of the electric storage device by the second DC converter,
It is possible to supply the minimum power required for the display device, reduce the loss for the supply, and efficiently perform the discharge.

According to a second aspect of the present invention, a solar cell, a rectifier that rectifies the power generated by the solar cell, a first DC converter that converts the voltage of the rectified power, and the voltage-converted power. A storage device for storing electricity, a display device that emits light by receiving discharge power supplied from the storage device, and an O display
And a second DC converter capable of variably controlling the ON drive time ratio. According to the invention described in claim 2, the second DC converter drives the display on / off and variably controls the ratio of the ON drive time. That is, the display device cannot display when the storage amount of the storage battery is insufficient. Therefore, the amount of stored electricity is detected by the electricity storage device voltage, and when the electricity storage amount is reduced, the power consumption can be reduced by reducing the ratio of the ON time of the display device, and the displayable time can be extended.

A third aspect of the present invention is a solar cell,
A rectifier that rectifies the power generated by the solar cell, a first DC converter that converts the voltage of the rectified power, a capacitor that stores the voltage-converted power, and a discharge power that is supplied from the capacitor. And a second DC converter capable of variably controlling the amount of drive current supplied to the display. According to the third aspect of the present invention, the second DC converter controls the drive current amount according to the degree of decrease in the amount of stored electricity, and reduces the power consumption by reducing the amount of drive current. The displayable time can be extended.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. This embodiment is characterized by using a solar cell having relatively high power generation efficiency as compared with the conventional display device (see FIG. 4), and using a capacitor 18 such as an electric double layer type capacitor.
To store electricity by interposing a DC-DC converter (first DC converter) 16 in the electricity storage circuit,
The point is that the LED group 24 is driven by interposing the DC-DC converter (21st DC converter) 20 in the ED drive circuit).

In FIG. 1, the output from the solar cell 10 is supplied to the storage circuit. The storage circuit 12 includes a rectifier 14 and a DC-DC converter 16, and stores the electric power generated from the solar cell 10 in the storage device 18. In this way, the storage circuit 1
2 is provided with the DC-DC converter 16, it is possible to improve the utilization efficiency of the solar cell 10 and store electricity.
The solar cell 10 can be covered by a small one.

As shown in FIG. 2, according to the display device according to the embodiment of the present invention, compared with the conventional device (see FIG. 5), the amount of stored electricity with respect to the sunshine duration is both in fine weather and in rainy weather. Both show that the storage efficiency is good.

The discharge power from the storage battery 18 is supplied to the drive circuit 20.
Is supplied to. The drive circuit 20 includes a DC-DC converter (second DC converter) 22, and drives and controls the LED group 24 according to the discharge voltage from the electric storage device 18. This DC
-The DC converter 22 turns the display to O by
It is a converter that can be driven N / OFF, and the ratio of ON time can be variably controlled. Reference numeral 26 indicates a resistance element. Although the storage capacity of the storage battery 18 is more than the required power for overnight, it is preferably about 3 to 4 times the power capacity (see the solid line in FIG. 3).

In the embodiment of the present invention, the amount of stored electricity is detected by the voltage of the storage device 18, and when the stored amount of electricity is reduced, the ratio of the ON time of the LED group 24 is reduced,
Alternatively, by reducing the current to the LED group 24,
The displayable time of the LED group 24 can be extended. In this way, an example in which the remaining charge amount is used as long as possible and the displayable time of the LED group 24 is lengthened when the charge amount decreases is shown by the broken line in the graph of FIG.

[0020]

As described above, according to the present invention,
While using the first DC converter as a storage circuit,
Since the second converter is used as the drive circuit, it is possible to efficiently store electricity in the electricity storage device and drive the display device efficiently and stably.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a display device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a stored power amount with respect to a sunshine duration in the display device according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a residual power storage amount with respect to the number of days without sunlight in the display device according to the embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a conventional display device.

FIG. 5 is an explanatory diagram showing a stored power amount with respect to a sunshine duration in a conventional display device.

FIG. 6 is an explanatory diagram showing a residual power amount with respect to the number of days without sunlight in a conventional display device.

[Explanation of symbols]

 10 Solar Cell 12 Storage Circuit 14 Rectifier 16 DC-DC Converter 18 Storage Battery 20 Drive Circuit 22 DC-DC Converter 24 LED Group

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masashi Takazawa 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Akira Kokonoki 2-chome, Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd.

Claims (2)

[Claims] 1. A solar cell, a rectifier that rectifies the power generated by the solar cell, a first DC converter that converts the voltage of the rectified power, a storage device that stores the voltage-converted power, and A solar cell type display comprising: a display which emits light by receiving discharge power supplied from a storage battery; and a second DC converter which converts the voltage of the discharge power supplied to the display. . 2. A solar cell, a rectifier that rectifies the power generated by the solar cell, a first DC converter that converts the voltage of the rectified power, and a storage device that stores the voltage-converted power. A display device that emits light by receiving discharge power supplied from a power storage device, and a second DC converter that is capable of ON / OFF driving the display device and variably controlling the ratio of the ON driving time And solar cell type display.