Pulsed L.E.D. illumination
First Claim
1. A method for driving a plurality of light-emitting diodes in a device having an electronic camera, the method comprising:
- providing a device having a camera and a plurality of light-emitting diodes (LEDs), wherein the plurality of light-emitting diodes emits light having a spectrum that is adjustable;
obtaining an image signal;
measuring a color balance of the image signal;
generating electrical pulses and delivering the electrical pulses to the plurality of LEDs; and
adjusting the spectrum of light from the plurality of LEDs based at least in part on the measured color balance.
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Accused Products
Abstract
An illumination source for a camera includes one or more LEDs, and an electrical circuit that selectively applies power from the DC voltage source to the LEDs, wherein the illumination source is suitable for handheld portable operation. In some embodiments, the electrical circuit further includes a control circuit for driving the LEDs with electrical pulses at a frequency high enough that light produced has an appearance to a human user of being continuous rather than pulsed, the control circuit changing a pulse characteristic to adjust a proportion of light output having the first characteristic color spectrum output to that having the second characteristic color spectrum output. Some embodiments provide an illumination source including a housing including one or more LEDs and a control circuit that selectively applies power from a source of electric power to the LEDs, thus controlling a light output color spectrum of the LEDs.
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Citations
20 Claims
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1. A method for driving a plurality of light-emitting diodes in a device having an electronic camera, the method comprising:
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providing a device having a camera and a plurality of light-emitting diodes (LEDs), wherein the plurality of light-emitting diodes emits light having a spectrum that is adjustable; obtaining an image signal; measuring a color balance of the image signal; generating electrical pulses and delivering the electrical pulses to the plurality of LEDs; and adjusting the spectrum of light from the plurality of LEDs based at least in part on the measured color balance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 20)
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11. An apparatus comprising:
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a device that includes an electronic video camera configured to output a video image signal; a measurement unit configured to measure a color balance of the video image signal; a plurality of light-emitting diodes (LEDs) mounted to the device, wherein the plurality of light-emitting diodes includes a first LED having a first characteristic spectrum and a second LED having a second characteristic spectrum, wherein the first characteristic spectrum is different from the second characteristic spectrum; and a control circuit, operably coupled to the measurement unit and to the plurality of LEDs, wherein the control circuit controls generation and delivery of a first pulsed electrical signal to the first LED and generation and delivery of a second pulsed electrical signal to the second LED, wherein the control circuit controls a pulse width of at least the first pulsed electrical signal in order to change a proportion of light output having the first characteristic spectrum to that having the second characteristic spectrum based at least in part on the measured color balance of the video image signal. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. An apparatus comprising:
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a casing; a plurality of light-emitting diodes (LEDs) mounted to the casing, wherein the plurality of LEDs includes a first LED having a first characteristic spectrum and a second LED having a second characteristic spectrum, wherein the first characteristic spectrum is different from the second characteristic spectrum; a user interface that receives input from a user; and a control circuit, operably coupled to the user interface and to the plurality of LEDs, wherein the control circuit controls generation and delivery of a first pulsed electrical signal to the first LED and generation and delivery of a second pulsed electrical signal to the second LED, wherein the control circuit controls a first characteristic of light of at least the first pulsed electrical signal based at least in part on received input from the user while the control circuit maintains an intensity of light from the plurality of LEDs. - View Dependent Claims (19)
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Specification