LED substrate and lighting apparatus

Abstract

To provide a technology that can control the timing of changes in the lighting state of LED elements without using control lines for synchronization.SOLUTION: An LED substrate 155 having a plurality of LED elements 157, 157 powered by a power supply unit, a switch element 165 electrically connected between the power supply unit and the plurality of LED elements, and a microcontroller 160 that switches switch elements on and off based on the timing of changes in the output voltage of the power supply unit, is provided.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to the technology of an LED substrate and a lighting device on which the LED substrate is mounted.

Background Art

[0002] Technologies related to LEDs have been proposed. For example, Japanese Patent Application Laid-Open No. 2008-39354 (Patent Document 1) discloses a lighting device for a refrigerator. In Patent Document 1, in a lighting device for a refrigerator including an LED substrate located inside the refrigerator and having light-emitting diodes mounted thereon as internal lighting, and a control substrate located outside the refrigerator and supplying voltage to the LED substrate according to the operating state of the refrigerator, a current limiting resistor for limiting the current to the light-emitting diodes is divided and mounted on each of the LED substrate and the control substrate, so that the heat generation load of the current limiting resistor can be dispersed to the LED substrate and the control substrate, and the thermal design margin of each substrate can be improved.

[0003] Also, Japanese Patent Application Laid-Open No. 2006-324671 (Patent Document 2) discloses an LED drive circuit having a dimming circuit. In Patent Document 2, the LED drive circuit has a PWM drive unit that provides a switching pulse whose width is adjusted by a voltage detected from a voltage detection resistor to a switch to control the on / off time of the switch, a comparison unit that compares the voltage value detected from the voltage detection resistor with an arbitrary dimming voltage value, and a PWM control unit that generates a control signal for increasing the on-time of the switching pulse output from the PWM drive unit when the comparison voltage value from the comparison unit increases and decreasing the on-time of the switching pulse output from the PWM drive unit when the comparison voltage value from the comparison unit decreases, and adjusts the brightness of the LED by controlling the width of the switching pulse output from the PWM drive unit in accordance with the dimming voltage value.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a technique capable of controlling the change timing of the lighting state of an LED element without using a control line for synchronization.

Means for Solving the Problems

[0006] According to an aspect of the present invention, there is provided an LED substrate including a plurality of LED elements supplied with power from a power supply device, a switch element electrically connected between the power supply device and the plurality of LED elements, and a microcomputer that switches ON / OFF of the switch element based on the timing at which the output voltage of the power supply device changes.

Effects of the Invention

[0007] As described above, according to the present invention, it becomes possible to control the change timing of the lighting state of the LED element without using a control line for synchronization.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. [First Embodiment] [Overall Configuration of Lighting Device 100]

[0010] First, with reference to FIGS. 1 and 2, the overall configuration of the lighting device 100 according to the present embodiment will be described.

[0011] The lighting device 100 according to the present embodiment mainly includes a support column 101, a solar cell 120, a power supply box 130, and a lamp unit 150. The power supply box 130 houses a controller 131, a seismic sensor 132, and a battery 134. More specifically, the controller 131, the seismic sensor 132, and the battery 134 are covered by a housing 136, a lid 137, and an upper lid 138.

[0012] During the day, the power generated by the solar cell 120 is stored in the battery 134. When night falls, or when the surroundings become dark, or in response to an operation command, the controller 131 supplies the power of the battery 134 to the lamp unit 150 to turn on the lamp unit 150.

[0013] More specifically, in the present embodiment, as shown in FIG. 3, the controller 131 of the lighting device 100 includes a microcomputer 1311 and a drive circuit 1312. The drive circuit 1312 is a power supply device using a PWM drive method for supplying power from the battery 134 to the lighting fixture 150. In the present embodiment, the drive circuit 1312 performs a PWM output in which the output voltage repeats ON / OFF, and by adjusting the ON duty of the output voltage, it is possible to switch between full lighting or blinking emission of the lighting fixture 150. As an example, the output voltage of the drive circuit 1312 is 12V and the frequency is 100Hz.

[0014] When it becomes night, the microcomputer 1311 controls the drive circuit 1312 at a predetermined duty. For example, the microcomputer 1311 supplies a large amount of power from the drive circuit 1312 to the lighting fixture 150 by designating a duty of 100% (DC voltage of 12V) during normal times. Also, when the microseismic sensor 132 detects an earthquake, the microcomputer 1311 supplies lower power from the drive circuit 1312 to the lighting fixture 150 by designating a lower duty different from normal times. <Overall Configuration of the LED Substrate 155>

[0015] Hereinafter, the configuration of the lighting fixture 150 and the LED substrate according to the present embodiment will be described. As shown in FIGS. 4 to 6, in the present embodiment, a plurality of LED substrates 155 are provided in the lighting fixture 150.

[0016] Each LED substrate 155 is mainly attached with a plurality of LED elements 157, 157 ···, a microcomputer 160, a smoothing circuit 163, a detection circuit 164, an FET switch 165 (switch element), and a connector 169.

[0017] First, the smoothing circuit 163 supplies a DC voltage (for example, 5V) obtained by rectifying and smoothing the output voltage from the drive circuit 1312 of the controller 131 transmitted through the connector 169 to the microcomputer 160.

[0018] The detection circuit 164 inputs the voltage from the drive circuit 1312 of the controller 131 to the microcomputer 160.

[0019] The FET switch 165 is connected in series between the drive circuit 1312 of the controller 131 and the plurality of LED elements 157, 157 ···. The FET switch 165 turns on or off the power supply to the plurality of LED elements 157, 157 ··· from the drive circuit 1312 according to the ON / OFF switching signal from the microcomputer 160.

[0020] The microcomputer 160 acquires the ON / OFF waveform of the voltage input from the drive circuit 1312 of the controller 131 according to the signal from the detection circuit 164. The microcomputer 160 inputs an ON / OFF switching command to the FET switch 165 based on the voltage waveform from the drive circuit 1312.

[0021] In the present embodiment, in the lighting device 100, each of the plurality of LED substrates 155 lights up or blinks at the same timing.

[0022] As shown in FIG. 7, when the input voltage from the drive circuit 1312 of the controller 131 is turned on based on the signal from the detection circuit 164, the microcomputer 160 of each LED substrate 155 executes the following processing. When the controller 131 lights up the lamp unit 150, first, during the constant voltage output period, it outputs a constant voltage (for example, a DC voltage of 12V). Then, when the controller 131 detects an earthquake with the seismic sensor 132 during the constant voltage output period, it performs a PWM output (the black part in FIG. 7) in which the output voltage repeats ON / OFF at a predetermined duty.

[0023] Based on the signal from the detection circuit 164, when the duty of the output voltage of the controller 131 is equal to or less than a predetermined value (for example, 50% or less), the microcomputer 160 controls the FET switch 165 so that a lighting period in which the FET switch 165 is turned ON and a lighting-off period in which the FET switch 165 is turned OFF repeat in synchronization with the start timing of the PWM output of the controller 131. In the present embodiment, in synchronization with the start timing of the PWM output, a lighting-off period (for example, 1 second) starts, after the lighting-off period, a lighting period (for example, 1 second) starts, and thereafter, the lighting-off period and the lighting period repeat. By blinking the lighting fixture 150, it is possible to notify the surroundings that the seismic sensor 132 has detected an earthquake. The measurement of the lighting-off period and the lighting period by the microcomputer 160 may be performed using a counter that measures the number of ON / OFF switches of the output voltage of the controller 131, or may be performed using a timer that measures time.

[0024] As described above, in the present embodiment, each microcomputer 160 of the plurality of LED substrates 155 blinks the LED elements 157 in synchronization with the timing at which the output voltage of the controller 131 changes. Therefore, the LED elements 157 of the plurality of LED substrates 155 can be blinked simultaneously without connecting between the plurality of LED substrates 155 with a control line or the like for synchronization.

[0025] Note that the form in which the plurality of LED substrates 155 are mounted on one lighting fixture 150 or one lighting device 100 is not limited. One LED substrate 155 may be mounted on one lighting fixture 150 or one lighting device 100, and a plurality of the lighting fixtures 150 or the lighting devices 100 may be arranged side by side on a road or a passage. [Second Embodiment]

[0026] Alternatively, the plurality of LED substrates 155 may be lit or extinguished with a shifted timing.

[0027] In the present embodiment, as shown in FIG. 8, each LED substrate 155 is mainly provided with a plurality of LED elements 157, 157 ···, a microcomputer 160, a smoothing circuit 163, a detection circuit 164, an FET switch 165, and a connector 169.

[0028] For the plurality of LED substrates 155, a waiting time from when the PWM output of the controller 131 starts until the start of the first lighting period is individually assigned. When the PWM output of the controller 131 starts (the black part in FIG. 9), each microcomputer 160 turns off the FET switch 165 during the waiting time assigned to itself. In the present embodiment, as an example, the lengths of the waiting times assigned to the first LED substrate 155, the second LED substrate 155, and the third LED substrate 155 are 0.5 seconds, 1 second, and 1.5 seconds, respectively. The measurement of the waiting time by the microcomputer 160 may be performed using a counter that measures the number of ON / OFF switches of the output voltage of the controller 131, or may be performed using a timer that measures time.

[0029] Then, as shown in FIG. 9, when the constant voltage output period of the controller 131 ends and the PWM output of the controller 131 starts (the black part in FIG. 9), each microcomputer 160 waits in the off state for the waiting time assigned to itself, and then controls the FET switch 165 so that the lighting period and the extinguishing period are repeated. Thereby, the timing at which the LED elements 157 blink on the plurality of LED substrates 155 can be made different. For example, by arranging the plurality of LED substrates 155 side by side, it is possible to produce an effect such that the light of the LED elements 157 moves (flows).

[0030] Thus, in this embodiment, each microcontroller 160 of the plurality of LED substrates 155 causes the LED elements 157 to blink such that the blinking timing is different from that of the LED elements 157 of other LED substrates 155 in synchronization with the timing at which the output voltage of the controller 131 changes. Therefore, the blinking timings of the LED elements 157 of the plurality of LED substrates 155 can be made different without connecting the plurality of LED substrates 155 to each other with a control line or the like for synchronization.

[0031] Further, the controller 131 is not limited to a configuration that performs PWM output after a constant voltage output period, and may output a constant voltage (duty 100%), for example, a DC voltage of 12V, instead of PWM output. In this case, after the constant voltage output period, the controller 131 turns off the output voltage (to 0V) during a predetermined period (output off period), and after the output off period, outputs a constant voltage again. When a constant voltage is output after the output off period, the microcontroller 160 controls the FET switch 165 so that the lighting period and the extinguishing period are repeated in synchronization with the start timing or the end timing of the output off period (the start timing of the constant voltage output). <Summary>

[0032] In the above embodiment, there is provided an LED substrate including a plurality of LED elements supplied with power from a power supply device, a switch element electrically connected between the power supply device and the plurality of LED elements, and a microcontroller that switches ON / OFF of the switch element based on the timing at which the output voltage of the power supply device changes.

[0033] Preferably, the microcontroller controls the switch element so that a lighting period in which the plurality of LED elements are lit and an extinguishing period in which the plurality of LED elements are extinguished are repeated in synchronization with the timing at which the output voltage changes.

[0034] Preferably, the power supply device is configured to perform PWM output after a constant voltage output period in which a constant voltage is output. The microcontroller controls the switch element so that the lighting period and the extinguishing period are repeated in synchronization with the start timing of the PWM output.

[0035] In the above-described embodiment, there is provided a lighting device including the above-described LED substrate and a power supply device.

[0036] In the above-described embodiment, there are provided a plurality of lighting devices each including the above-described LED substrate and a power supply device. The power supply device supplies power to the plurality of LED substrates.

[0037] In the above-described embodiment, there are provided a plurality of lighting devices each including the above-described LED substrate and a power supply device. The power supply device supplies power to the plurality of LED substrates. Each of the plurality of microcontrollers controls a switching element such that at least one of the start timings of the lighting period and the extinguishing period is different from one of the start timings in another LED substrate.

[0038] The disclosed embodiments should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the scope of the claims be included.

Explanation of Reference Numerals

[0039] 100: Lighting device 101: Support column 120: Solar cell 130: Power supply box 131: Controller 1311: Microcontroller 1312: Drive circuit 132: Seismic sensor 134: Battery 136: Housing 137: Lid 138: Upper lid 150: Lighting fixture 155: LED substrate 157: LED element 160: Microcontroller 163: Smoothing circuit 164: Detection circuit 165: FET switch 169: Connector

Claims

1. A plurality of LED elements supplied with power from a power supply device; A switch element electrically connected between the power supply device and the plurality of LED elements; A microcomputer that switches ON / OFF of the switch element based on a timing at which the output voltage of the power supply device changes. An LED substrate comprising the same.

2. The microcomputer controls the switch element so that a lighting period during which the plurality of LED elements light up and a non-lighting period during which the plurality of LED elements are turned off repeat in synchronization with a timing at which the output voltage changes. The LED substrate according to Claim 1.

3. The power supply device is configured to output PWM after a constant voltage output period in which a constant voltage is output. The microcomputer controls the switch element so that the lighting period and the non-lighting period repeat in synchronization with a start timing of the PWM output. The LED substrate according to Claim 2.

4. An LED substrate according to any one of Claims 1 to 3; The power supply device. A lighting device comprising the same.

5. A plurality of LED substrates according to any one of Claims 1 to 3; The power supply device. Comprising the same. The power supply device supplies power to the plurality of LED substrates. A lighting device comprising the same.

6. A plurality of LED substrates according to Claim 3; The power supply device. Comprising the same. The power supply device supplies power to the plurality of LED substrates. Each of the plurality of microcomputers controls the switch element so that at least one start timing of the lighting period and the non-lighting period is different from the start timing of the one in another LED substrate. A lighting device comprising the same.

Images