LED-based light fixture
First Claim
Patent Images
1. A method, comprising:
- illuminating a first portion of a light guide with a first light that has a first incident time-averaged brightness;
illuminating a second portion of the light guide with a second light that has a second incident time-averaged brightness different from the first incident time-averaged brightness;
extracting a fraction of the first light from the light guide to form first exiting light that has a first exiting time-averaged brightness; and
extracting a fraction of the second light from the light guide to form second exiting light that has a second exiting time-averaged brightness,a ratio of the second exiting time-averaged brightness to the first exiting time-averaged brightness being closer to unity than a ratio of the second incident time-averaged brightness to the first incident time-averaged brightness.
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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.
15 Citations
20 Claims
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1. A method, comprising:
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illuminating a first portion of a light guide with a first light that has a first incident time-averaged brightness; illuminating a second portion of the light guide with a second light that has a second incident time-averaged brightness different from the first incident time-averaged brightness; extracting a fraction of the first light from the light guide to form first exiting light that has a first exiting time-averaged brightness; and extracting a fraction of the second light from the light guide to form second exiting light that has a second exiting time-averaged brightness, a ratio of the second exiting time-averaged brightness to the first exiting time-averaged brightness being closer to unity than a ratio of the second incident time-averaged brightness to the first incident time-averaged brightness. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method, comprising:
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illuminating a first portion of a light guide with a first light that has a first duty cycle and a first incident time-averaged brightness; illuminating a second portion of the light guide with a second light that has a second duty cycle different from the first duty cycle and has a second incident time-averaged brightness; extracting, with a first portion of the light guide having a first density of light extraction features, a fraction of the first light to form first output light that has a first exiting time-averaged brightness; and extracting, with a second portion of the light guide having a second density of light extraction features, a fraction of the second light to form second output light that has a second exiting time-averaged brightness, a ratio of the second exiting time-averaged brightness to the first exiting time-averaged brightness being closer to unity than a ratio of the second incident time-averaged brightness to the first incident time-averaged brightness. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A system, comprising:
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a light guide having a first portion and a second portion, the first portion configured to be illuminated with a first light that has a first incident time-averaged brightness, the second portion configured to be illuminated with a second light that has a second incident time-averaged brightness different from the first incident time-averaged brightness, the first portion configured to extract a fraction of the first light from the light guide to form first exiting light that has a first exiting time-averaged brightness, the second portion configured to extract a fraction of the second light from the light guide to form second exiting light that has a second exiting time-averaged brightness, a ratio of the second exiting time-averaged brightness to the first exiting time-averaged brightness being closer to unity than a ratio of the second incident time-averaged brightness to the first incident time-averaged brightness.
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Specification