LED substrate and lighting apparatus

Abstract

To allow the emission intensity of LED elements to be adjustable for each LED substrate.SOLUTION: An LED substrate 155 having a plurality of LED elements 157, 157 powered by a power supply unit 130 with PWM drive system, 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 during the on period of 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 Unexamined Patent Application Publication 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 for illuminating the inside of the refrigerator, and a control substrate located outside the refrigerator and supplying a 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] Further, Japanese Unexamined Patent Application Publication No. 2006-324671 (Patent Document 2) discloses an LED driving circuit having a dimming circuit. In Patent Document 2, the LED driving circuit has a PWM driving 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 driving unit when the comparison voltage value from the comparison unit increases and decreasing the on-time of the switching pulse output from the PWM driving 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 driving unit according to 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 enable adjustment of the light emission intensity of LED elements for each LED substrate.

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 using a PWM driving method, 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 during the ON period of the output voltage of the power supply device.

Effects of the Invention

[0007] As described above, according to the present invention, it is possible to adjust the light emission intensity of LED elements for each LED substrate.

Brief Description of the Drawings

[0008]

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DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts 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 this embodiment mainly includes a support column 101, a solar cell 120, a power supply box 130, and a lighting fixture 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 electric 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 lights the lighting fixture 150 by supplying the electric power of the battery 134 to the lighting fixture 150.

[0013] More specifically, in this 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 the electric power from the battery 134 to the lighting fixture 150. In this 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, PWM dimming of the lighting fixture 150 is possible. As an example, the output voltage of the drive circuit 1312 is 12V and the frequency is 100 Hz.

[0014] When night falls, the microcomputer 1311 controls the drive circuit 1312 at a predetermined duty for each time period. For example, from 18:00 to 22:00, the microcomputer 1311 supplies a large amount of electric power from the drive circuit 1312 to the lighting fixture 150 by specifying a high duty, from 22:00 to 2:00, supplies a medium amount of electric power from the drive circuit 1312 to the lighting fixture 150 by specifying a medium duty, and from 2:00 to 6:00, supplies a low amount of electric power from the drive circuit 1312 to the lighting fixture 150 by specifying a low duty. <Overall Configuration of 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] On each LED substrate 155, mainly, 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 are attached.

[0017] First, the smoothing circuit 163 supplies a DC voltage (for example, 5V) obtained by rectifying and smoothing the output voltage (PWM 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. For example, the microcomputer 160 sends an ON signal to the FET switch 165 during a predetermined ratio (for example, 62%) of a period of one cycle of the power supply voltage from the controller 131, and sends an OFF signal to the FET switch 165 during the remaining ratio (for example, 38%).

[0021] More specifically, as shown in FIG. 7, the microcomputer 160 calculates the timing at which the voltage from the drive circuit 1312 is turned on and the ratio X (e.g., 89%) of the ON period in one pulse of the power supply voltage based on the ON / OFF waveform of the voltage input from the drive circuit 1312 of the controller 131. Then, the microcomputer 160 calculates the power supply ratio Z (e.g., 62%) that results in a predetermined ratio Y (e.g., 70%) of the ratio.

[0022] Here, the ratio X of the ON period in one cycle of the power supply voltage is a value that the controller 131 should determine. On the other hand, the predetermined ratio Y is defined or set for the LED substrate 155 and is stored in the microcomputer 160 of the LED substrate 155.

[0023] While observing the ON / OFF waveform of the input voltage, the microcomputer 160 turns on the FET switch 165 at the timing when the voltage from the drive circuit 1312 is turned on, and repeats turning off the FET switch 165 at the timing when the power supply ratio Z within one cycle of the power supply voltage has elapsed. As a result, the plurality of LED elements 157, 157... will light up with a brightness corresponding to a predetermined ratio Y (e.g., 70%) of the power input from the controller 131.

[0024] That is, the LED substrate 155 according to the present embodiment lights up with a brightness corresponding to a predetermined ratio Y defined for the LED substrate 155 among the power input from the controller 131 as the power supplied from the outside. By adjusting the predetermined ratio Y stored in the microcomputer 160 of the LED substrate 155, it becomes possible to light up the lighting device 100 and the LED substrate 155 with a brightness suitable for the surroundings or the like, regardless of the manufacturing date or performance differences of the LED elements 157 mounted on the lighting device 100 or the LED substrate 155. [Second Embodiment]

[0025] In the above-described embodiment, the FET switch 165 was turned on in accordance with the timing at which the voltage from the drive circuit 1312 was turned on, and the FET switch 165 was turned off when a predetermined ratio Y in one cycle was reached. However, the form of turning the FET switch 165 on and off in accordance with the ON / OFF waveform of the input voltage from the drive circuit 1312 is not limited.

[0026] In the present embodiment, as shown in FIG. 8, there is no detection circuit for monitoring the ON / OFF waveform of the voltage input from the drive circuit 1312 of the controller 131. In the present embodiment, the microcomputer 160 turns the FET switch 165 on and off at a speed about 100 times the ON / OFF frequency of the drive circuit 1312, for example, 10 KHz or the like.

[0027] More specifically, also in the present embodiment, the ratio X of the ON period in one cycle of the power supply voltage is a numerical value that the controller 131 should determine. The predetermined ratio Y is defined or set for the LED substrate 155 and is stored in the microcomputer 160 of the LED substrate 155.

[0028] Then, as shown in FIG. 9, the microcomputer 160 switches the ON / OFF of the FET switch 165 at 10 KHz. And the FET switch 165 is turned on only for a predetermined ratio Y (for example, 70%) in one cycle of the ON / OFF, and the FET switch 165 is turned off only for a predetermined ratio (1 - Y) (for example, 30%) in one cycle of the ON / OFF. As a result, the plurality of LED elements 157, 157 ··· light up with a brightness corresponding to a predetermined ratio Y (for example, 70%) of the power input from the controller 131. [Third Embodiment]

[0029] 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.

[0030] Note that the form in which a plurality of LED substrates 155 are mounted on one luminaire 150 or one lighting device 100 is not limited. One LED substrate 155 may be mounted on one luminaire 150 or one lighting device 100, and a plurality of such luminaires 150 or lighting devices 100 may be installed side by side on a road or a passage.

[0031] In the present embodiment, as shown in FIG. 10, 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.

[0032] Then, as shown in FIG. 11, 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 on each LED board 155 executes the following processes. When the controller 131 lights the luminaire 150, first, during the constant voltage output period, it outputs a constant voltage (for example, a DC voltage of 12V). Then, after the constant voltage output period, the controller 131 performs a PWM output in which the output voltage repeats ON / OFF at a predetermined duty. Based on the signal from the detection circuit 164, the microcomputer 160 controls the FET switch 165 so that a lighting period in which the ON / OFF of the FET switch 165 is switched during the ON period of the output voltage of the controller 131 and a lighting-off period in which the FET switch 165 is turned off are repeated in synchronization with the start timing of the PWM output of the controller 131. In this embodiment, in synchronization with the start timing of the PWM output, a lighting-off period (for example, 1 second) starts, and after the lighting-off period, a lighting period (for example, 1 second) starts, and then the lighting-off period and the lighting period are repeated. 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. Also, the control of the FET switch 165 during the lighting period may be synchronous control in which the FET switch 165 is turned on in synchronization with the timing when the output voltage of the controller 131 is turned on, as in the first embodiment described above, or the FET switch 165 may be PWM-controlled at a frequency higher than the output voltage of the controller 131, as in the second embodiment.

[0033] Thus, in this embodiment, each microcomputer 160 on the plurality of LED boards 155 blinks the LED elements 157 in synchronization with the output voltage of the controller 131. Therefore, the LED elements 157 on the plurality of LED boards 155 can be blinked simultaneously without connecting the plurality of LED boards 155 to each other with a control line or the like for synchronization. [Fourth Embodiment]

[0034] Alternatively, the plurality of LED boards 155 may be turned on and off with a time shift.

[0035] In the present embodiment, as shown in FIG. 12, 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.

[0036] A waiting time from when the PWM output of the controller 131 starts until the start of the first lighting period is individually assigned to each of the plurality of LED substrates 155. When the PWM output of the controller 131 starts, each microcomputer 160 turns off the FET switch 165 during the assigned waiting time. 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 or OFF switches of the output voltage of the controller 131, or may be performed using a timer that measures time.

[0037] Then, as shown in FIG. 13, when the assigned waiting time elapses, each microcomputer 160 controls the FET switch 165 so that the lighting period and the extinguishing period are repeated. Thereby, it is possible to make the timing at which the LED elements 157 blink different among the plurality of LED substrates 155. 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).

[0038] As described above, in the present embodiment, each microcomputer 160 of the plurality of LED substrates 155 blinks the LED elements 157 so that the blinking timing is different from that of the LED elements 157 of the other LED substrates 155 in synchronization with the output voltage of the controller 131. Therefore, it is possible to make the blinking timings of the LED elements 157 of the plurality of LED substrates 155 different without connecting between the plurality of LED substrates 155 with a control line or the like for synchronization. <Summary>

[0039] In the above embodiment, an LED substrate is provided, which includes a plurality of LED elements supplied with power from a power supply device using a PWM driving method, a switch element electrically connected between the power supply device and the plurality of LED elements, and a microcomputer that switches the ON / OFF of the switch element during the ON period of the output voltage of the power supply device.

[0040] Preferably, the microcomputer turns on the switch element in synchronization with the timing when the output voltage turns on, and turns off the switch element during the ON period of the output voltage.

[0041] Preferably, the microcomputer performs PWM control on the switch element at a frequency higher than the output voltage.

[0042] In the above embodiment, a lighting device is provided, which includes the above LED substrate and a power supply device.

[0043] In the above embodiment, a plurality of lighting devices are provided, each including the above LED substrate and a power supply device. The power supply device supplies power to the plurality of LED substrates.

[0044] Preferably, the power supply device is configured to output PWM after a constant voltage output period in which a constant voltage is output. The plurality of microcomputers of the plurality of LED substrates control the switch element so that a lighting period in which the ON / OFF of the switch element is switched during the ON period of the output voltage of the power supply device and a lighting-off period in which the switch element is turned off are repeated in synchronization with the start timing of the PWM output.

[0045] Preferably, each of the plurality of microcomputers controls the switch element so that at least one of the start timings of the lighting period and the lighting-off period is different from one of the start timings of other LED substrates.

[0046] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims be included.

Explanation of Reference Numerals

[0047] 100: Lighting device 101: Support column 120: Solar cell 130: Power box 131: Controller 1311: Microcomputer 1312: Drive circuit 132: Seismic sensor 134: Battery 136: Housing 137: Cover 138: Upper cover 150: Lamp 155: LED substrate 157: LED element 160: Microcomputer 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 using a PWM drive method, A switch element electrically connected between the power supply device and the plurality of LED elements, A microcomputer that switches the ON / OFF of the switch element during the ON period of the output voltage of the power supply device, and an LED substrate comprising the same.

2. The microcomputer turns on the switch element in synchronization with the timing at which the output voltage turns on, and turns off the switch element during the ON period of the output voltage. The LED substrate according to Claim 1.

3. The microcomputer PWM-controls the switch element at a frequency higher than the output voltage. The LED substrate according to Claim 1.

4. An illumination device comprising the LED substrate according to any one of Claims 1 to 3 and the power supply device.

5. A plurality of LED substrates according to any one of Claims 1 to 3, and the power supply device, wherein the power supply device supplies power to the plurality of LED substrates. An illumination device.

6. The power supply device is configured to output PWM after a constant voltage output period in which a constant voltage is output. The plurality of microcomputers of the plurality of LED substrates synchronize with the start timing of the PWM output, and during the ON period of the output voltage of the power supply device, turn on / off the switch element. The illumination device according to Claim 5, wherein the switch element is controlled so that a lighting period and a non-lighting period in which the switch element is turned off are repeated.

7. Each of the plurality of microcomputers controls the switch element such that at least one of the start timings of the lighting period and the non-lighting period is different from the start timing of the one in another LED substrate. The illumination device according to Claim 6. ​ ​

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