Light emitting device for AC power operation
First Claim
1. A light emitting device, comprising:
- a light emitting diode (LED) chip comprising a plurality of light emitting cells electrically connected in series, in parallel, or in series-parallel; and
a transparent member covering the LED chip, the transparent member comprising a first phosphor and a second phosphor,wherein the first phosphor is a delay phosphor configured to be excited by light emitted from the light emitting cells to emit light in a visible light range,wherein the first phosphor has a longer decay time than the decay time of the second phosphor,wherein the light emitting cells are configured to be periodically turned on and off during an operation of the light emitting device,and wherein the first phosphor is configured to emit light for a first period of time after the light emitting cells are turned off, and wherein the second phosphor is configured to emit light for a second period of time after the light emitting cells are turned off, the first period being longer than the second period.
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Accused Products
Abstract
Disclosed is an improved light-emitting device for an AC power operation. An AC light-emitting device according to the present invention employs a variety of means by which light emission time is prolonged during a ½ cycle in response to a phase change of an AC power source and a flicker effect can be reduced. For example, the means may be switching blocks respectively connected to nodes between the light emitting cells, switching blocks connected to a plurality of arrays, or a delay phosphor. Further, there is provided an AC light-emitting device, wherein a plurality of arrays having the different numbers of light emitting cells are employed to increase light emission time and to reduce a flicker effect.
37 Citations
12 Claims
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1. A light emitting device, comprising:
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a light emitting diode (LED) chip comprising a plurality of light emitting cells electrically connected in series, in parallel, or in series-parallel; and a transparent member covering the LED chip, the transparent member comprising a first phosphor and a second phosphor, wherein the first phosphor is a delay phosphor configured to be excited by light emitted from the light emitting cells to emit light in a visible light range, wherein the first phosphor has a longer decay time than the decay time of the second phosphor, wherein the light emitting cells are configured to be periodically turned on and off during an operation of the light emitting device, and wherein the first phosphor is configured to emit light for a first period of time after the light emitting cells are turned off, and wherein the second phosphor is configured to emit light for a second period of time after the light emitting cells are turned off, the first period being longer than the second period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification