Brightness control of a status indicator light
First Claim
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1. A method for varying a luminance of a light, comprising:
- varying an input to the light, the input setting a rate of change in the luminance of the light;
setting a threshold value for the luminance of the light; and
adjusting a rate of change of the input when the luminance is below the threshold to adjust the rate of change in the luminance of the light so that there is a break point below the threshold where the rate of change in the luminance changes, wherein the adjustment to the rate of change in the luminance of light is determined by subtracting an input value from the threshold to determine the distance from the threshold and dividing the distance by an adjustment factor.
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Abstract
An apparatus and method for controlling the brightness and luminance of a light, such as an LED. The embodiment may vary the brightness and luminance of the LED in a variety of ways to achieve a variety of effects. The exemplary embodiment may vary the rate at which the LED'"'"'s luminance changes, such that an observer perceives the change in the LED'"'"'s brightness to be smooth and linear as a function of time, regardless of the ambient light level. Changes to the LED'"'"'s luminance may be time-constrained and/or constrained by a maximum or minimum rate of change.
57 Citations
14 Claims
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1. A method for varying a luminance of a light, comprising:
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varying an input to the light, the input setting a rate of change in the luminance of the light; setting a threshold value for the luminance of the light; and adjusting a rate of change of the input when the luminance is below the threshold to adjust the rate of change in the luminance of the light so that there is a break point below the threshold where the rate of change in the luminance changes, wherein the adjustment to the rate of change in the luminance of light is determined by subtracting an input value from the threshold to determine the distance from the threshold and dividing the distance by an adjustment factor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for varying a luminance of a light, comprising:
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varying an input to the light, the input affecting the luminance; setting a threshold value for the luminance of the light; and adjusting a rate of change of the input when the luminance is below the threshold to gradually and increasingly slow a rate of change in the luminance; wherein the luminance is decreasing; and the operation of adjusting a rate of change of the input comprises decreasing the rate of change of a duty cycle of the pulse-width modulation output relative to a previously-determined rate; wherein the operation of setting a threshold value for the luminance of the light comprises setting a threshold value for the pulse-width modulation output; wherein the operation of adjusting a rate of change of the input when the luminance is below the threshold comprises; in the event the pulse-width modulation output is below the threshold, subtracting the current pulse-width modulation output from the threshold to yield a threshold distance; determining a slope adjustment; determining if an initial rate of change is less than the slope adjustment; and in the event the initial rate is less than the slope adjustment, permitting the pulse-width modulation output to change by a minimum increment. - View Dependent Claims (12, 13, 14)
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Specification