JP2018014375A - Blinking control method for led - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blinking control method capable of achieving improvement of visibility and power saving by intermittently gradually making an LED bright or dark or changing brightness at random in a different way from a conventional LED blinking control method of continuously changing brightness formed by pulse-modulating a driving current with a predetermined voltage.SOLUTION: A plurality of pulses with different voltages formed by changing a current peak value are intermittently applied at predetermined time intervals during one blinking period of an LED from turning on to off.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an LED blinking control method that can intermittently greatly change the luminance at the time of LED blinking.

  Recently, LEDs that exhibit high luminance with low power have been developed, and many display devices such as road warning lights and advertisement lights using these have been found. In general, these display devices repeatedly blink LEDs at a constant cycle. Is displayed.

  In the meantime, as shown in FIG. 5, a conventional LED blinking method is one in which a pulse current formed by pulse-modulating a drive current having a predetermined voltage is output by an oscillation circuit and blinked (brightness control PWM (Pulse Width)), and the current value at the time of lighting is constant, but the apparent light emission luminance can be changed by changing the blinking duty ratio (pulse width) of the pulse signal.

  However, in the PWM control, when a constant current is supplied for a certain period of time, a predetermined blinking is repeated with a predetermined brightness. For this reason, there is a problem that the blinking of light appears monotonously without any change in luminance at the time of lighting or afterimage after the light is turned off. In addition, there is a problem that a large amount of current flows through the current limiting resistor during lighting and power consumption during lighting is large.

  Thus, for example, Japanese Patent Application Laid-Open No. 2002-72944 (Patent Document 1), Japanese Patent Application Laid-Open No. 2004-270201 (Patent Document 2), Japanese Patent Application Laid-Open No. 2010-54790 (Patent Document 3), etc. For this reason, the process of turning off the LED that emits light from the set maximum brightness and reducing the brightness to turning it off is longer than the process of turning on and increasing the brightness and reaching the set maximum brightness. LED blinking methods such as “Adjust and display the information in a blinking manner” and “To turn on the energy, the lighting process is performed instantaneously” are presented.

  For example, as shown in FIGS. 5 and 6, the improved blinking method of these LEDs changes the duty ratio of the pulse current by the light of the same intensity formed by pulse-modulating the drive current having a predetermined voltage. The visual effect is enhanced by continuously changing the luminance of the screen.

  Therefore, there is a problem that the amount of light having the same intensity is turned on at a constant interval and the same current peak, and the luminance changes continuously, so that the visual effect is poor and the power consumption is not reduced so much.

JP 2002-72944 A Japanese Patent Laid-Open No. 2004-270201 JP 2010-54790 A

  An object of the present invention is to provide an LED blinking control method capable of solving the problems of the conventional improved LED blinking method and further improving visibility and saving power. It is.

  The present invention, which has been made to solve the above-mentioned problems, intermittently applies a plurality of pulses having different voltages with different current peak values at predetermined times during one blinking period from turning on to turning off an LED. It is characterized by doing.

  In particular, visibility can be further improved by arranging a plurality of pulses having different voltages to be applied intermittently in the order of voltage or randomly.

  According to the present invention, the brightness is changed so that it gradually becomes brighter or gradually darker intermittently rather than continuously, or randomly, that is, the light is moved during lighting, and the visibility is improved. Further, it can be blinked with power saving compared to the conventional brightness control PWM.

The simple block circuit diagram which shows the display apparatus using preferable embodiment of LED light emission control method which concerns on this invention. The graph of the LED light emission control method in this invention. The graph of the different LED light emission control method in this invention. The graph of the further different LED light emission control method in this invention. It is the graph of the conventional brightness control PWM which shows specifically the transition of the pulse signal from a pulse circuit, and light emission luminance. It is a graph of the brightness control PWM of the light extinction process which shows a prior art example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 4 show simplified block circuit diagrams of an LED display device such as a road indicator using the LED light emission control method according to the present invention, and mainly a solar cell 1 for generating electric power and The secondary battery 2 that stores the electric power generated by the solar battery, the lighting pattern control circuit 5 that stores in advance the lighting pattern from lighting to extinguishing, and the voltage control by the control signal from the lighting pattern control circuit 5 A step-up power supply circuit 3 that applies power from the secondary battery 2 to the LED current control circuit 4 to perform PWM (Pulse Width Modulation), and a voltage control PWM (Pulse Width Modulation) determined by the LED current control circuit 4 in advance. It consists of LEDs 6 that flash control. In the drawing, reference numeral 7 denotes a sleep timer.

  In the present embodiment having the above configuration, a plurality of pulses having different voltages whose current peak values are changed are intermittently applied at a predetermined time during one blinking period from turning on to turning off the LED. The lighting pattern is pre-programmed and those control signals are transmitted to the boosting power supply circuit 3, and a current for voltage control pulse control is formed in the LED current control circuit 4 and is made to flow intermittently to the LED 6 sequentially. Voltage control PWM (Pulse Width Modulation) having a waveform pattern as shown in FIG.

  More specifically, as shown in FIG. 2, the voltage control PWM (Pulse Width Modulation) in the present embodiment sets, for example, 1440 ms as one blinking period, and has an interval of 540 ms, for example. Flash continuously.

  Then, for example, six pulses are transmitted in the time direction with a pulse interval of 180 ms and a pulse width of 17 ms during the one blinking period 1440 ms.

  By the way, this pulse is different from brightness control PWM (Pulse Width Modulation) in which the brightness is changed by changing the width of the conventional pulse shown in FIGS. 5 and 6, and both the duty and the current peak value of each pulse. Furthermore, the pulse interval is the interval in which the human eye perceives light continuously like the conventional brightness control PWM (Pulse Width Modulation), while the pulse interval is By setting the interval to be discontinuous to the eyes, it is possible to feel a change in brightness intermittently.

  Therefore, by transmitting pulses with different current values at intervals that are visually felt to be discontinuous to cause the LED 6 to emit light (flash), the viewer can observe a continuous change in luminance as in the past in one flashing period. In contrast, the luminance is changed so that it gradually becomes brighter or darker intermittently, so that the visibility is improved.

  In this embodiment, since the lighting pulse is intermittently transmitted as compared with the conventional brightness control PWM (Pulse Width Modulation) that transmits the lighting pulse almost continuously, the current consumption can be further reduced. Is one of the major advantages.

  Note that the light-emitting device, the blinking interval, the pulse width, and the interval shown in this embodiment are examples, and are not limited to these numbers, and can be changed as appropriate according to the purpose of use and the purpose of use. Yes.

  FIG. 3 shows a different light emission pattern of the present invention. In the embodiment shown in FIG. 2, the pulse current gradually decreases from a low current peak state, that is, from a dark state in one blinking period. It is set so as to be high, that is, intermittently bright, and the viewer first feels strong light compared to the embodiment shown in FIG. To change.

  According to the voltage control PWM (Pulse Width Modulation) of the present embodiment, since a pulse (bright pulse) due to a large current is generated at the same time as lighting, it becomes conspicuous at the time of lighting. It is also effective when installed in a bright place.

  Also, the voltage control PWM (Pulse Width Modulation) pattern shown in FIGS. 2 and 3 may be combined as right justified and left justified as before, and the current peak value may be lowered by shifting the front and back lighting timings. it can.

  Further, FIG. 4 shows the case where the intermittently lit pulse current gradually increases (lightens) as in the pattern shown in FIG. 2, or the intermittently lit pulse current gradually decreases (darkens) as shown in FIG. In contrast, since the brightness changes randomly within one blinking period and lights up intermittently, the movement of light is large and the visibility can be improved.

  1 solar cell, 2 secondary battery, 3 boost power supply circuit, 4 LED current control circuit, 5 lighting pattern control circuit, 6 LED, 7 sleep timer

Claims (2)

  A method for controlling the blinking of an LED, wherein a plurality of pulses having different voltages whose current peak values are changed are intermittently applied at a predetermined time during one blinking period from turning on to turning off the LED.   The LED blinking control method according to claim 1, wherein the visibility is further improved by arranging a plurality of pulses having different voltages to be applied intermittently in order of voltage, or by randomly arranging the pulses.