JP2024087936A - LED lighting equipment - Google Patents

Abstract

[Problem] To provide a large number of LED lighting fixtures each consisting of a set of LEDs with a high color temperature and LEDs with a low color temperature, and when some of the LED lighting fixtures are turned on in advance and the remaining other LED lighting fixtures are turned on with a delay, flickering occurs in the other LED lighting fixtures, which is undesirable for the LED lighting fixture as a whole.
[Solution] The color temperature of some of the LED lighting fixtures is raised when a predetermined time has elapsed since the start of lighting, and the other LED lighting fixtures are made to emit light from an off state to the same illuminance as some of the LED lighting fixtures in a time shorter than the predetermined time, and are controlled to have the same color temperature as some of the LED lighting fixtures when the predetermined time has elapsed.
[Selected figure] Figure 2

Description

The present invention relates to an LED lighting device equipped with a power supply unit that supplies power to an LED lighting fixture incorporating multiple types of LED chips that have different color temperatures when lit, so that the illuminance and color temperature can be changed.

It is known that the brightness of an LED is roughly proportional to the current. Therefore, when dimming the LED to increase or decrease its illuminance, constant current control is used to control the current flowing through the LED. On the other hand, there are cases where a single LED fixture contains two types of LED chips with different color temperatures, such as a daylight LED chip and an incandescent LED chip, and color adjustment control is performed to change the color temperature of the entire LED fixture by changing the ratio of illuminance of each LED chip (see, for example, Patent Document 1).

When recreating the fade-in state of a conventional filament light bulb with an LED lighting device, when the light switch is turned on, the illuminance increases stepwise from a low illuminance and low color temperature, and the color temperature also increases.

JP 2016-62881 A (FIG. 1)

The illuminance of an LED is roughly proportional to the current, but no current flows until the applied forward voltage exceeds Vf (forward voltage) determined for each LED. In other words, the LED will not light up until the applied voltage exceeds Vf, so when the applied voltage is increased and Vf is reached, the current value rises sharply and the LED emits bright light from the start.

Since LEDs use constant current control as described above, if a large current flows at Vf, the voltage is lowered to reduce the current. As a result, the illuminance settles to a low level, but even if only for a moment, the illuminance remains high (overshoot).

Therefore, to prevent the discomfort caused by such overshoot, multiple LED fixtures are installed, and some of the LED fixtures are illuminated when the light is turned on, and the remaining LED fixtures are slowly lit up so that the illuminance and color temperature are reached after a specified time.

However, the above-mentioned overshoot phenomenon occurs when these other parts are turned on, causing a problem in which the entire LED lighting device flickers during the initial fade-in state.

In view of the above problems, the present invention aims to provide an LED lighting device equipped with multiple LED lighting fixtures that does not flicker during the initial fade-in state.

In order to solve the above problems, the LED lighting device of the present invention is an LED lighting device equipped with a power supply unit that supplies power to an LED lighting fixture incorporating multiple types of LED chips that have different color temperatures when lit, so that the illuminance and color temperature can be changed. A plurality of LED lighting fixtures are connected to the power supply unit, and the power supply to some of the plurality of LED lighting fixtures and the power supply to the other parts can be controlled separately. When lighting starts, power is supplied to the some of the LED lighting fixtures so that the color temperature and illuminance become predetermined values, and the other LED lighting fixtures are not supplied with power and are in an off state. The color temperature of the some of the LED lighting fixtures is raised when a predetermined time has passed since lighting starts, and the other LED lighting fixtures are made to emit light from an off state to the same illuminance as the some of the LED lighting fixtures in a time shorter than the predetermined time, and are controlled to the same color temperature as the some of the LED lighting fixtures when the predetermined time has passed.

If the other LED lighting fixtures were to be brought from the off state at the start of fade-in to the same illuminance and color temperature as the partial LED lighting fixtures over the specified time, flickering would occur as described above. Therefore, by increasing the illuminance in a time shorter than the specified time, i.e., by increasing the rate at which the illuminance increases, flickering is not noticeable even if it occurs.

If the illuminance and color temperature of the other LED lighting fixtures reach the illuminance and color temperature of the part of the LED lighting fixtures before the specified time has elapsed, the color temperature of the other LED lighting fixtures is then raised to the same level as the color temperature of the part of the LED lighting fixtures, thereby ensuring a smooth fade-in for the entire LED lighting device.

As is clear from the above explanation, the LED lighting device of the present invention increases the rate at which the illuminance of the other LED lighting fixtures rises during the initial fade-in period more quickly than the conventional device, so that even if flicker does occur, the flicker is not noticeable for the entire LED lighting device.

FIG. 1 shows a configuration of an embodiment of the present invention. A graph showing an example of changes in illuminance and color temperature during fade-in Graph showing another example of changes in illuminance and color temperature during fade-in

Referring to FIG. 1, 1 is a power supply unit of an LED lighting device according to the present invention. This power supply unit 1 receives AC power from an external commercial power supply PS, converts the AC power into DC power, and supplies it to each power supply unit 12. Two power supply units 12 form a pair, and an LED 21 with a high color temperature is connected to one power supply unit 12, and an LED 22 with a low color temperature is connected to the other power supply unit 12. These LEDs 21, 22 are housed in one LED lighting fixture 2-1. There are two types of LED lighting fixtures, with some LED lighting fixtures designated 2-1 and the remaining other LED lighting fixtures designated 2-2.

Referring to FIG. 2, when the lighting switch is turned on while the LED lighting devices 2-1 and 2-2 are off, the power supply unit 1 applies current to the LEDs 21 and 22 to gradually increase the illuminance, a process known as fading in. At this time, current is applied to some of the LED lighting devices 2-1 so that the illuminance is immediately set to about 10% and the color temperature is set to 2000K (Kelvin) (A1). The other LED lighting devices 2-2 are left in an off state (B1). The color temperature of some of the LED lighting devices 2-1 is controlled to rise to 2500K and the illuminance is also slightly increased after a predetermined time has passed from the start (A2). The other LED lighting devices 2-2 are turned on before the above-mentioned predetermined time has passed, and after the illuminance and color temperature shown in B2 are set to the same state as the state of some of the LED lighting devices 2-1 (A2) after the predetermined time has passed. After that, the some of the LED lighting devices 2-1 and the other LED lighting devices 2-2 change in sync so that the illuminance is 100% and the color temperature exceeds 6000K. As shown in this diagram, in the past, the other LED lighting fixture 2-2 would change directly from the state shown in B1 to the state shown in A2, causing flickering when this happened. However, by making the change in the other LED lighting fixture 2-2 more abrupt than in the past, as shown in this diagram, flickering is less noticeable.

However, the control is not limited to that shown in FIG. 2. As shown in FIG. 3, the same effect can be achieved by maintaining the off state from B1 to B2, and then changing the state from B2 to A2.

The present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention.

1 Power supply section 12 Power supply unit 21 High color temperature LED
22 Low color temperature LED
2-1 Some LED fixtures 2-2 Other LED fixtures

Claims (2)

An LED lighting device equipped with a power supply unit that supplies power to an LED lighting fixture incorporating multiple types of LED chips with different color temperatures when lit, so that the illuminance and color temperature can be changed. A plurality of LED lighting fixtures are connected to the power supply unit, and the power supply to some of the plurality of LED lighting fixtures and the power supply to the other parts can be controlled separately. When lighting starts, power is supplied to the some of the LED lighting fixtures so that the color temperature and illuminance become predetermined values, and the other LED lighting fixtures are not supplied with power and are in an off state. The color temperature of the some of the LED lighting fixtures is raised when a predetermined time has passed since lighting starts, and the other LED lighting fixtures are made to emit light from an off state to the same illuminance as the some of the LED lighting fixtures in a time shorter than the predetermined time, and the color temperature is controlled to the same as the color temperature of the some of the LED lighting fixtures when the predetermined time has passed. The LED lighting device according to claim 1, characterized in that if the illuminance and color temperature of the other LED lighting fixtures reach the illuminance and color temperature of the part of the LED lighting fixtures before the predetermined time has elapsed, the color temperature of the other LED lighting fixtures is then raised to the same level as the color temperature of the part of the LED lighting fixtures.

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