Method and apparatus for measuring radiation from a plurality of light sources
First Claim
1. An apparatus for measuring the intensity of radiation from a source of radiation in the presence of ambient radiation having a periodic component comprising:
- means for generating a first plurality of discrete signals, each of said signals having a magnitude protional to the intensity of said periodic component at a different predetermined time in a cycle of said component in the absence of radiation from said source and a second plurality of corresponding discrete signals, each of said second plurality of signals having a magnitude proportional to the combined intensity of said periodic component and radiation from said source at the same times in a subsequent cycle of said periodic component; and
means for processing said first and said second signals for indicating the intensity of said radiation from said source.
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Abstract
An apparatus for testing the optical output of light-emitting devices in the presence of ambient light, with means for compensating for said ambient light, is described. The d.c. and periodic components of the ambient light are measured and stored during a time when the apparatus is not being subjected to radiation from the device under test (DUT). When radiation from the DUT is received, the resulting signal is processed with the stored ambient light intensity data, and an output proportional to the intensity of the radiation from the DUT and compensated for the ambient light is provided.
34 Citations
19 Claims
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1. An apparatus for measuring the intensity of radiation from a source of radiation in the presence of ambient radiation having a periodic component comprising:
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means for generating a first plurality of discrete signals, each of said signals having a magnitude protional to the intensity of said periodic component at a different predetermined time in a cycle of said component in the absence of radiation from said source and a second plurality of corresponding discrete signals, each of said second plurality of signals having a magnitude proportional to the combined intensity of said periodic component and radiation from said source at the same times in a subsequent cycle of said periodic component; and means for processing said first and said second signals for indicating the intensity of said radiation from said source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for testing the optical output of a multi-segmented light-emitting device, each of said segments being a source of radiation, in the presence of ambient light having a periodic component comprising:
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means for generating a plurality of first signals in the absence of radiation from said source, each of said first signals being proportional to the intensity of said periodic component at a predetermined time in the cycle of said periodic component; means for generating a plurality of second signals, each of said second signals being associated with a particular one of said first signals and proportional to the combined intensity of said periodic component and the radiation from one of said segments during said corresponding predetermined time in the cycle of said periodic component; and means for processing associated first and second signals for providing an indication of the intensity of the radiation from each of said segments. - View Dependent Claims (11, 12)
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13. An apparatus for measuring the intensity of radiation from a light-emitting device in the presence of ambient radiation having a periodic componet comprising:
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means for detecting said radiation; means for amplifying the output of said detecting means; means for integrating the output of said amplifying means; means for sampling and holding the output of said integrating means; control means for selevtively providing a first plurality of discrete outputs, each of said outputs corresponding to the intensity of said ambient radiation from said light-emitting device at a different predetermined time in a cycle of said periodic component and a second plurality of discrete outputs corresponding to the intensity of said ambient radiation and said radiation from said light-emitting device combined at corresponding times in a subsequent cycle of said periodic component; and means for providing an output corresponding to the difference between said first and said second outputs, said difference being the intensity of said radiation from said light-emitting device. - View Dependent Claims (14, 15, 16, 17)
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18. A method of measuring the intensity of light from a light-emitting device in the presence of ambient light having a periodic component comprising the steps of:
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measuring the intensity of said periodic ambient light at a plurality of predetermined times in a cycle of said ambient light in the absence of light from said light-emitting device for providing a first plurality of signals; measuring the intensity of said ambient light and the light from said light-emitting device combined, at corresponding times in a subsequent cycle of said periodic ambient light, for providing a second plurality of signals; generating an output corresponding to the difference between said first and said second signals for providing an indication of the intensity of the radiation from said device. - View Dependent Claims (19)
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Specification