LED-BASED LIGHT FIXTURE
First Claim
1. An illumination system, comprising:
- a driver circuit including a plurality of tap points, the driver circuit being configured to produce a cyclical waveform and switch the tap points on and off in sequence during each cycle of the waveform;
a light guide having a light emitting surface, the light emitting surface having a plurality of portions, each portion having a different light extraction pattern formed thereon, each light extraction pattern including a different plurality of light extraction features, and each light extraction pattern having a different light extraction feature density; and
a plurality of light emitting diodes (LEDs), each LED being electrically coupled to a different respective one of the plurality of tap points and coupled to a different respective one of the plurality of portions of the light guide, such that a length of a period for which the LED is powered on during each cycle of the waveform is inversely proportional to the light extraction feature density of the respective portion'"'"'s light extraction pattern.
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Accused Products
Abstract
An illumination system is disclosed that is arranged to compensate for variations in brightness between different LEDs in the system. The system may include an array of LEDs coupled to a light guide that is provided with a plurality of light extraction patterns. Each light extraction pattern may include a plurality of light extraction features. The light extraction patterns may differ from one another in the density of the features. Light extraction patterns having a greater density may be combined with LEDs in the array that are less bright, whereas light extraction patterns having a lower feature density may be combined with LEDs in the array that are brighter.
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Citations
20 Claims
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1. An illumination system, comprising:
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a driver circuit including a plurality of tap points, the driver circuit being configured to produce a cyclical waveform and switch the tap points on and off in sequence during each cycle of the waveform; a light guide having a light emitting surface, the light emitting surface having a plurality of portions, each portion having a different light extraction pattern formed thereon, each light extraction pattern including a different plurality of light extraction features, and each light extraction pattern having a different light extraction feature density; and a plurality of light emitting diodes (LEDs), each LED being electrically coupled to a different respective one of the plurality of tap points and coupled to a different respective one of the plurality of portions of the light guide, such that a length of a period for which the LED is powered on during each cycle of the waveform is inversely proportional to the light extraction feature density of the respective portion'"'"'s light extraction pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An illumination system, comprising:
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a light guide; a driver circuit including a plurality of tap points, the driver circuit being configured to produce a cyclical waveform and switch the tap points on and off in sequence during each cycle of the waveform; and a plurality of first light emitting diode (LED) groups that are coupled to the light guide and have a same average on-time, each of the first LED groups including a respective first LED and a respective second LED that are disposed adjacently to one another and coupled to different tap points of the driver circuit, the first LED in any given first LED group being coupled in series with one or more other first LEDs that are part of other first LED groups, and the second LED in any given first LED group being coupled in series with one or more other second LEDs that are part of other first LED groups. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An illumination system, comprising:
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a light guide having a plurality of portions; a driver circuit including a plurality of tap points, the driver circuit being configured to produce a cyclical waveform and switch the tap points on and off in sequence during each cycle of the waveform; a plurality of first LEDs coupled in series, each first LED being coupled to a different tap point of the light guide, and each first LED being coupled to a different portion of the light guide, such that each portion of the light guide is coupled to a different respective first LED; a plurality of second LEDs coupled in series, each second LED being coupled to a different tap point of the light guide, and each second LED being coupled to a different portion of the light guide, such that each portion of the light guide is also coupled to a different respective second LED, and an average on-time of all LEDs that are coupled to any given portion of the light guide is substantially the same. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification