JP2004192936A - Flash lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple and low cost flash lamp which does not require a special light receiving element for distinguishing between light and darkness. <P>SOLUTION: The flash lamp has a LED 5 as a light emitting means and as a light receiving means. A light receiving circuit 8 which outputs a light and darkness detecting signal corresponding to the light and darkness of circumference based on a light receiving state of the LED 5 or a driving circuit 9 which makes the LED 5 emit the light is connected to the LED 5 with an analog switch 6. A one chip computer 4 controls a flashing as follows. The analog switch 6 is switched to connect the light receiving circuit 8 and the light and darkness detecting signal is obtained. By using the signal, a control loop judging the light and darkness of the circumference is carried out. While carrying out the control loop, the analog switch 6 is switched to connect the driving circuit 9 during a prescribed lighting time for making the LED 5 emit the light when the circumference is dark. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flash lamp that performs flashing light emission.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a self-luminous flash lamp embedded in a road, a device that stores power in a solar cell when the sun is bright and bright in the daytime and blinks and emits light when the surroundings become dark after sunset is known. In this type of conventional flash lamp, the distinction between light and dark is performed using a dedicated light receiving element.
[0003]
[Problems to be solved by the invention]
As described above, in this type of conventional flash lamp, it is necessary to provide a dedicated light receiving element for distinguishing between light and dark separately from the light emitting element.
[0004]
It is important that flash lamps for road embedding and the like can be mass-produced easily and inexpensively, and in that sense, it is desirable to have as few parts as possible. For example, if the above-described light receiving element dedicated to the distinction between light and dark can be eliminated, it can greatly contribute to simplification of the apparatus and cost reduction.
[0005]
In view of the above problems, an object of the present invention is to provide a flash lamp which can be configured simply and inexpensively without requiring a light receiving element dedicated to distinguishing light and dark.
[0006]
[Means for Solving the Problems]
According to an embodiment of the present invention, there is provided an LED that functions as a light emitting unit and a light receiving unit, a light receiving circuit that outputs a light / dark detection signal according to surrounding light / dark based on a light receiving state of the LED, A drive circuit that emits light, switch means for connecting either the light receiving circuit or the drive circuit to the LED, and switching the switch means to the light receiving circuit side to obtain a light / dark detection signal from the light receiving circuit, A control loop for judging light and dark is executed, and during the execution of the control loop, when the surroundings are dark, the control means is switched to the drive circuit side for a predetermined lighting time for a predetermined lighting time to cause the LED to emit light. .
[0007]
Alternatively, a configuration is adopted in which a waiting time corresponding to the predetermined lighting time is inserted when the surroundings are bright so that the cycle of the control loop is substantially constant both when the surroundings are bright and when the surroundings are dark. .
[0008]
Alternatively, a configuration in which a solar cell is used for a power supply unit that supplies power to each unit is employed.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0010]
FIG. 1 shows the configuration of a self-luminous flash lamp according to the present invention. In FIG. 1, reference numeral 1 denotes a solar cell. Electricity generated by the solar cell 1 is stored in an electric double layer capacitor 2 of a charging circuit 7, stabilized by a regulator 3, and supplied to each unit of the device described later. Do. The electric double layer capacitor 2 may be composed of another type of storage battery.
[0011]
By this power supply, the control circuit 10 is driven, and the light emission of the LED (light emitting diode) 5 is controlled. The control circuit 10 includes a one-chip microcomputer 4 having an AD conversion function.
[0012]
In the present embodiment, the LED 5 functions as a light emitting unit, and also functions as a light receiving unit for determining brightness.
[0013]
Therefore, the LED 5 can be connected to the light receiving circuit 8 or the light emitting drive circuit 9 via the analog switch 6. Of course, since the LED 5 is also used as a light receiving means for determining brightness, the LED 5 is arranged in a portion around the device where the brightness can be determined.
[0014]
The light receiving circuit 8 is configured to generate a voltage signal corresponding to the light receiving intensity of the LED 5 from the LED 5 and input the voltage signal to an AD conversion input terminal of the control circuit 10. The LED 5 is made of a semiconductor as is well known, and emits light by applying a current and generates current by receiving the light. The light receiving circuit 8 inputs the light receiving current of the LED 5 to the control circuit 10 as a light / dark detection voltage signal using a fixed resistor for current detection or the like.
[0015]
The drive circuit 9 uses the electric power stored in the electric double layer capacitor 2 of the charging circuit 7 to turn on and off the LED 5 in accordance with a command from the control circuit 10.
[0016]
The analog switch 6 connects either the light receiving circuit 8 or the driving circuit 9 to the LED 5 according to a command from the control circuit 10.
[0017]
In the above configuration, a voltage signal corresponding to the received light intensity is input from the LED 5 to the control circuit 10 and A / D converted, and the brightness is determined by comparing the magnitude with a preset threshold value. When the one-chip microcomputer 4 of the control circuit 10 determines from the output of the LED 5 connected to the light receiving circuit 8 by the analog switch 6 that the surroundings are bright, the one-chip microcomputer 4 directly connects the LED 5 to the light receiving circuit 8 via the analog switch 6. Conversely, when it is determined that the surroundings are dark, the analog switch 6 connects the LED 5 to the drive circuit 9 for light emission for a predetermined time. Thereafter, a series of operations of switching the connection to the light receiving circuit 8 again and performing the light / dark determination is repeated.
[0018]
FIG. 2 shows an example of a control procedure of such a control circuit 10. The procedure in FIG. 2 can be stored in the ROM 4a of the one-chip microcomputer 4 as a control program for the one-chip microcomputer 4. At the start of the processing in FIG. 2, the analog switch 6 is connected to the light receiving circuit 8 side.
[0019]
In steps S1 and S2, the control circuit 10 inputs the light / dark detection voltage signal of the light receiving circuit 8 as digital data.
[0020]
Then, in step S3, a comparison is made with a preset threshold value. When the surroundings are bright enough to generate enough power by the solar cell 1, the process proceeds to step S4, and when dark, the process proceeds to step S6.
[0021]
When the surroundings are bright, in steps S4 and S5, a predetermined time (0.1 sec in step S4, 0.9 sec in step S5) is waited while the LED 5 is connected to the light receiving circuit, and the process returns to step S1 again.
[0022]
On the other hand, if the surroundings are dark, such as after sunset, the analog switch 6 is switched to the drive circuit 9 in step S6, the LED 5 emits light for a predetermined time (0.1 sec in this case) in step S7, and the analog switch 6 is turned on in step S8. After returning to the light receiving circuit 8, the process proceeds to step S5, waits for a predetermined time (0.9 sec in this case) with the LED 5 connected to the light receiving circuit, and returns to step S1 again.
[0023]
That is, when the surroundings are bright, a loop is executed in approximately one second (steps S4 and S5) to detect the light receiving state of the LEDs 5 and determine the surrounding brightness without turning on the LEDs 5. On the other hand, when the surroundings are dark, the LED 5 emits light for 0.1 sec (step S7), and after waiting for 0.9 sec (step S5), a loop is executed to detect the light receiving state of the LED 5 and determine the brightness of the surroundings. The entire processing cycle is substantially constant, one second, as in the bright case. As shown in FIG. 2, steps S4 and S5 are divided, and when the surroundings are bright, the process passes through step S4 in which a dummy waiting time corresponding to the lighting time of the LED 5 is inserted. Can be eliminated.
[0024]
As described above, according to the present embodiment, the LED is used as the light emitting unit, and the configuration that functions as the light receiving unit for determining the brightness is adopted. There is an excellent effect that the number of parts can be reduced and the apparatus can be simply and inexpensively configured.
[0025]
In the above description, the configuration using the solar cell 1 and the charging circuit 7 as the power source is adopted. However, the configuration of the power source is arbitrary, and a commercial AC power source or a battery (regardless of whether it is a rechargeable type or a dry battery) is used as the power source. Also in the case of using the LED, it is needless to say that the same effect as described above can be obtained by using the LED as the light emitting means and the light receiving means for determining the brightness.
[0026]
【The invention's effect】
As is apparent from the above description, according to the present invention, an LED that functions as a light emitting unit and a light receiving unit is used, a light / dark detection signal corresponding to the surrounding light / dark is obtained based on the light receiving state of the LED, and the surrounding light / dark is determined. When the surroundings are dark during execution of the control loop, a configuration is adopted in which the LED is illuminated for a predetermined lighting time. Therefore, a light receiving element dedicated to light / dark determination is not required, and the surroundings are dark. It is possible to provide an excellent flash lamp which can blink the LED only during the period and can be configured simply and inexpensively.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a flash lamp employing the present invention.
FIG. 2 is a flowchart illustrating a control procedure of a control circuit of FIG. 1;
[Explanation of symbols]
1 solar cell 2 electric double layer capacitor 4 1 chip microcomputer 5 LED
6 Analog switch 7 Charging circuit 8 Light receiving circuit 9 Drive circuit 10 Control circuit

Claims (3)

An LED functioning as a light emitting unit and a light receiving unit;
A light receiving circuit that outputs a light / dark detection signal according to the surrounding light / dark based on the light receiving state of the LED;
A drive circuit for causing the LED to emit light,
Switch means for connecting either the light receiving circuit or the drive circuit to the LED,
By switching the switch means to the light receiving circuit side, a light / dark detection signal is obtained from the light receiving circuit, and a control loop for judging surrounding light / dark is executed. A flash lamp comprising control means for switching to the drive circuit for the lighting time to emit the LED. A waiting time corresponding to the predetermined lighting time is inserted when the surroundings are bright so that the cycle of the control loop is substantially constant both when the surroundings are bright and when the surroundings are dark. 2. The flash lamp according to 1. The flash lamp according to claim 1, wherein a power supply unit that supplies power to each unit is configured by a solar cell.

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