JP2002270381A - Street light - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce power consumption, running cost and installation cost. SOLUTION: A power supply unit 5 having a solar cell 21 and a secondary battery 23 charged by a direct current generated by the solar cell 21; a light / dark detection circuit 3 for detecting outdoor light / dark; It includes a diode unit 4 having a light emitting surface formed in an array, a switching element 5a connected between the secondary battery 23 and the diode unit 4, and a switching control circuit 5b for controlling switching of the switching element 5a. The switching control circuit 5b controls the switching element 5a to be in a switching on state when the light / dark detection circuit 3 detects a dark state outside, so that the power supply unit turns on the diode unit 4.
To supply power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a street light.

[0002]

2. Description of the Related Art A conventional street lamp generally uses an incandescent bulb, a fluorescent lamp or a mercury lamp as a light source, and turns on the light source using a power supply of 100 volts AC.

[0003]

However, this conventional street light has the following problems. That is, first,
Since an incandescent bulb or the like is used as a light source, there is a problem that power consumption is large. Secondly, there is a problem that the running cost is increased as a result of the necessity of regular replacement work in order to avoid the non-lighting state due to the burnout of the bulb.
Third, to use 100 volts AC as the power source,
There is a problem that construction work for laying electric wires to the street light is required, and the installation cost is soaring.

[0004] The present invention has been made in view of the above problems, and has as its main object to provide a street light that consumes less power and can reduce running costs and installation costs.

[0005]

According to one aspect of the present invention, there is provided a street lamp, comprising: a power supply unit having a solar cell and a secondary battery charged by a direct current generated by the solar cell; A light / dark detection circuit for detecting outdoor light / dark, a diode unit having a light emitting surface formed by arranging a plurality of light emitting diodes, a switching element connected between the secondary battery and the diode unit, A switching control circuit for controlling switching of a switching element, wherein the switching control circuit controls the switching element to a switching on state when the outdoor dark state is detected by the light / dark detection circuit, and the power supply unit And supplying power to the diode unit.

According to a second aspect of the present invention, in the street light of the first aspect, the power supply unit includes a capacitor charged by a DC current generated by the solar cell;
A charge control circuit that supplies the stored energy of the capacitor when the voltage of the capacitor exceeds a predetermined voltage with respect to the voltage of the secondary battery to charge the secondary battery. .

According to a third aspect of the present invention, in the street light according to the first or second aspect, the switching control circuit controls the expansion and contraction of the switching-on period of the switching element to cause the switching from the secondary battery to the diode unit. It is characterized in that the supplied power is controlled to increase or decrease.

[0008] The street light according to the fourth aspect is characterized by the first to third aspects.
Wherein the diode unit is configured by connecting a plurality of unit blocks formed by connecting a plurality of the light emitting diodes and one current limiting resistor in series, in parallel. And

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a street light according to the present invention will be described below with reference to the accompanying drawings.

First, the configuration of the street light 1 will be described with reference to FIGS.
This will be described with reference to FIG.

As shown in FIG. 1, the street light 1 includes a power supply unit 2, a light / dark detection circuit 3, a diode unit 4, and a control unit 5. As shown in FIG. 2, the street light 1 includes a lighting head unit 6 and a support pillar 7 and is installed upright on the ground 8.

As shown in FIG. 1, the power supply section 2 includes a solar cell 21, a charging circuit 22, and a secondary battery 23. As shown in FIG. 2, the solar cell 21 is disposed on the upper surface of the illumination head unit 6, and is configured to be able to receive sunlight during the day. In this case, for example, a single crystal type having an outer shape of about 35 cm square is used as the solar cell 21. In addition, this type of solar cell is about 17V
Of about 0.8 A. For this reason, the solar cell 21 is configured by connecting approximately two solar cells of this type in parallel. The charging circuit 22 is configured using the charging device disclosed in Japanese Patent Application No. 2000-212547 by the present applicant. Specifically, the charging circuit 22 includes a capacitor as a power storage unit and a charging control circuit. In this case, the capacitor is charged by the direct current generated by the solar cell 21. When the voltage of the capacitor exceeds a predetermined voltage with respect to the voltage of the secondary battery 23, the charge control circuit supplies the energy stored in the capacitor to charge the secondary battery 23. The secondary battery 23 is configured by a lithium ion battery or the like. In this case, the rechargeable battery 23 is configured such that a required number of batteries matching the temperature condition and the charging condition are connected in series and parallel, and can output a sufficient current at a required voltage value.

The light / dark detection circuit 3 is configured using a light detection element such as a photodiode, and is installed on the outer peripheral surface of the support column 7. The light / dark detection circuit 3 is connected to the outside (the street light 1).
(When the outside becomes darker than a preset brightness), the detection signal SDK is output.

The diode unit 4 is an ultra-bright light emitting diode (for example, 10 mm in diameter, about 20 mA, 3
0000 mcd (Millicandela)) are arranged in a plane to form about 100 to 200 pieces, and function as a light source.
In this case, the diode unit 4 is disposed on the lower surface of the illumination head unit 6 as shown in FIG.
Of the ground 8 (road surface) below the vehicle. In addition, the diode unit 4 is configured by connecting a plurality of unit blocks formed by connecting a plurality of light emitting diodes and one current limiting resistor in series. With this configuration, the number of current limiting resistors used in the diode unit 4 can be reduced, so that the diode unit 4 can be downsized. The diode unit 4 can be arranged on the head section 6.

The control section 5 has a control function of supplying power from the power supply section 2 to the diode unit 4 when the light / dark detection circuit 3 detects a dark state outside. Specifically, for example, as shown in FIG. 1, the control unit 5 includes a switching element (transistor, FET, or the like) 5 a connected between the secondary battery 23 and the diode unit 4,
A switching (S / W) control circuit 5b for outputting a pulse-like drive signal SDR shown in FIG. 3 to shift the switching element 5a to the on state when the detection signal SDK is output from the light / dark detection circuit 3 Have been. In this case, the switching control circuit 5b outputs the drive signal SDR at a constant cycle T, and controls the pulse width Tw corresponding to the switching-on period of the drive signal SDR in accordance with the operation amount of an operation switch (not shown). Therefore, the pulse width of the luminance and power consumption of the diode unit 4 is controlled by the ratio of the pulse width Tw to the cycle T, that is, the duty ratio of the drive signal SDR. Normally, the duty ratio of the drive signal SDR is set in advance by an operation switch for each installation location in accordance with the use conditions (brightness of the diode unit 4, illumination time, etc.) at the installation location of the street light 1.

The illumination head 6 is mounted on the upper part of the support column 7. The support column 7 houses therein the secondary battery 23, the charging circuit 22, the control unit 5, and the like.
In addition, a configuration in which the secondary battery 23, the charging circuit 22, the control unit 5, and the like are housed in a dedicated container is adopted, and a configuration in which this container is fixed to the support column 7 or buried in the ground 8 is adopted. Can also. Further, a configuration in which the secondary battery 23, the charging circuit 22, the control unit 5, and the like are housed in the illumination head unit 6 can be adopted. The unit 5 may be configured as one lighting unit, and the lighting unit may be configured to be detachable from the support column 7. In this case, the lighting unit can be replaced for each lighting unit, or the mounting work of the lighting unit can be separately performed after the support pillar 7 is installed first.

Next, the overall operation of the street light 1 will be described.

In the daytime, the solar cell 21 receives sunlight and generates electric power, and the charging circuit 22 outputs a direct current generated by the solar cell 21 to charge the secondary battery 23. On the other hand, the light / dark detection circuit 3 maintains the state in which the output of the detection signal SDK is stopped because the outdoors are bright. Therefore, the secondary battery 23 is charged by the charging circuit 22 without discharging. Therefore, the secondary battery 23 is charged efficiently. In the morning and evening,
And when the weather is cloudy even during the daytime,
However, the charging circuit 22 efficiently charges the secondary battery 23 with a small amount of energy. That is, in the charging circuit 22, when the capacitor is gradually charged with the DC current generated by the solar cell 21 and the voltage of the capacitor exceeds a predetermined voltage with respect to the voltage of the secondary battery 23, the charging control circuit The secondary battery 23 is charged by supplying the energy stored in the capacitor at one time. As a result, the secondary battery 23 is more efficiently charged than when it is directly and gradually charged with the direct current generated by the solar cell 21.

On the other hand, in the evening, the light / dark detection circuit 3 detects a dark state outside and outputs a detection signal SDK to the control unit 5.
Output to At this time, in the control unit 5, the switching control circuit 5b outputs the drive signal SDR to drive the switching element 5a. Therefore, the driving signal SDR shown in FIG.
, A DC current based on the stored energy of the secondary battery 23 is supplied to the diode unit 4. Therefore, the diode unit 4 is pulse-driven and lights up intermittently. In this case, when the light emitting diode is turned on and off at high speed, generally, a person perceives the same level of brightness as in continuous light emission due to an afterimage effect. Therefore, it is possible to efficiently illuminate while suppressing the power consumption of the diode unit 4. Thereafter, at dawn, the light / dark detection circuit 3 stops outputting the detection signal SDK. At this time, when the control unit 5 stops outputting the drive signal SDR, the diode unit 4 automatically shifts to the light-off state.

The present invention is not limited to the above embodiments of the present invention. For example, a configuration in which a clock circuit is provided in the control unit 5 and the duty ratio of the drive signal SDR is changed according to the time can be adopted. In this case, the duty ratio is increased to increase the brightness of the diode unit 4 in the evening time when there are many traffic, and conversely, the duty ratio is reduced to increase the brightness of the diode unit 4 in the middle of the night when traffic is little. And at the same time, the secondary battery 2
3 can be efficiently illuminated while reducing power consumption. Further, by adopting a configuration in which a light / dark analog signal having a voltage value corresponding to the outdoor brightness is output as the light / dark detection circuit 3, the duty ratio of the drive signal SDR can be changed according to the outdoor brightness. . Further, the switching element is not limited to a semiconductor element, but may be a mechanical switch element such as a relay. However, from the perspective of downsizing, lower power consumption and lower price of street lights,
It is preferable to use a semiconductor element.

[0021]

As described above, according to the street lamp of the first aspect, the use of the light emitting diode as the light source allows
Unlike an incandescent bulb or the like, maintenance can be made unnecessary for a long period of time without breaking the bulb. Therefore, running costs can be reduced. Also,
By using a light emitting diode as a light source, it is possible to efficiently illuminate while reducing power consumption. further,
Since AC 100 volts is not used as a power source, the laying work of the electric wire becomes unnecessary, so that the laying cost can be reduced.

According to a second aspect of the present invention, there is provided a street light, comprising: a capacitor which is charged by a DC current generated by a solar cell; The power supply unit is composed of a charge control circuit that supplies the energy stored in the capacitor to charge the secondary battery. , The secondary battery can be charged efficiently.

Furthermore, according to the street light of claim 3,
The switching control circuit controls the expansion and contraction of the switching-on period of the switching element to increase or decrease the power supplied from the secondary battery to the diode unit. Since the supplied power can be controlled, the stored energy of the secondary battery can be used efficiently.

According to the fourth aspect of the present invention, a plurality of unit blocks formed by connecting a plurality of light emitting diodes and one current limiting resistor in series are connected in parallel to form a diode unit. As a result, the number of current limiting resistors can be reduced, so that the diode unit can be reduced in size and weight. Further, for example, since the lighting head of the street light can be reduced in weight, the load applied to the support pillar can be reduced, so that the durability of the street light can be improved. At the same time, the number of current limiting resistors can be reduced, so that the manufacturing cost of the street light can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining a configuration of a street light 1 according to an embodiment of the present invention.

FIG. 2 is an external view showing a configuration of a street light 1. FIG.

FIG. 3 is a timing chart for explaining a relationship between a drive signal SDR and a detection signal SDK.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Street light 2 Power supply part 3 Light / dark detection circuit 4 Diode unit 5 Control part 5a Switching element 5b Switching control circuit 21 Solar cell 22 Charging circuit 23 Secondary battery

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02J 7/35 F21S 1 / 10Z // F21Y 101: 02 9/02 Q

Claims (4)

[Claims] 1. A power supply unit having a solar cell and a secondary battery charged by a direct current generated by the solar cell, a light / dark detection circuit for detecting light / darkness outside, and a plurality of light emitting diodes arranged. A diode unit having the formed light-emitting surface, a switching element connected between the secondary battery and the diode unit, and a switching control circuit for controlling switching of the switching element. A street light, wherein the switching element is controlled to be in a switching-on state when the light-dark detection circuit detects the dark state outside, and the power supply unit supplies power to the diode unit. 2. The power supply unit includes: a capacitor charged by a DC current generated by the solar cell; and a capacitor connected when a voltage of the capacitor exceeds a predetermined voltage with respect to a voltage of the secondary battery. The street light according to claim 1, further comprising: a charge control circuit that supplies the stored energy to charge the secondary battery. 3. The switching control circuit according to claim 1, wherein the switching control circuit controls expansion / contraction of a switching-on period of the switching element to increase / decrease power supplied from the secondary battery to the diode unit. Street light. 4. The diode unit according to claim 1, wherein a plurality of unit blocks formed by connecting a plurality of the light emitting diodes and one current limiting resistor in series are connected in parallel. The street light according to any of 1 to 3.