Dynamic range control for optical encoders
First Claim
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1. A method for dynamically adjusting output of a light source of an optical encoder that is operable to detect movement of a watch crown, the method comprising:
- receiving a first output voltage from a first photodiode of a plurality of photodiodes, wherein the first output voltage is associated with a first input current that was applied to the light source at a first time period;
receiving a second output voltage from a second photodiode of the plurality of photodiodes, wherein the second output voltage is associated with the first input current that was applied to the light source at the first time period;
comparing the first output voltage to the second output voltage to obtain a dynamic range;
comparing the dynamic range to a target range to determine whether an alignment of the watch crown with respect to the plurality of photodiodes or the light source is changed; and
estimating, using the comparison between the dynamic range and the target range, an input current for the light source, the estimated input current offsetting the alignment of the watch crown when the alignment of the watch crown is determined to impact a signal-to-noise ratio of the optical encoder, wherein the estimated input current is applied to the light source at a second time period.
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Abstract
Embodiments of the present disclosure provide a method and system for dynamically controlling a current that is applied to a light source of an optical encoder.
139 Citations
20 Claims
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1. A method for dynamically adjusting output of a light source of an optical encoder that is operable to detect movement of a watch crown, the method comprising:
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receiving a first output voltage from a first photodiode of a plurality of photodiodes, wherein the first output voltage is associated with a first input current that was applied to the light source at a first time period; receiving a second output voltage from a second photodiode of the plurality of photodiodes, wherein the second output voltage is associated with the first input current that was applied to the light source at the first time period; comparing the first output voltage to the second output voltage to obtain a dynamic range; comparing the dynamic range to a target range to determine whether an alignment of the watch crown with respect to the plurality of photodiodes or the light source is changed; and estimating, using the comparison between the dynamic range and the target range, an input current for the light source, the estimated input current offsetting the alignment of the watch crown when the alignment of the watch crown is determined to impact a signal-to-noise ratio of the optical encoder, wherein the estimated input current is applied to the light source at a second time period. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A non-transitory computer-readable storage medium encoding computer executable instructions which, when executed by a processor, perform a method for dynamically adjusting a light source of an optical encoder that is operable to detect movement of a watch crown, the method comprising:
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receiving a first output voltage from a first photodiode of a plurality of photodiodes, wherein the first output voltage is associated with a first input current that was applied to the light source at a first time period; receiving a second output voltage from a second photodiode of the plurality of photodiodes, wherein the second output voltage is associated with the first input current that was applied to the light source at the first time period; comparing the first output voltage to the second output voltage to obtain a dynamic range; comparing the dynamic range to a target range to determine whether an alignment of the watch crown with respect to the plurality of photodiodes or the light source is changed; and estimating, using the comparison between the dynamic range and the target range, an input current for the light source, the estimated input current offsetting the alignment of the watch crown when the alignment of the watch crown is determined to impact a signal-to-noise ratio of the optical encoder, wherein the estimated input current is applied to the light source at a second time period. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A watch crown, comprising:
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an optical encoder comprising; a light source; a plurality of photodiodes; a shaft having an encoding pattern disposed thereon, wherein the shaft is configured to reflect light from the light source into the plurality of photodiodes; and a dynamic range module; a cap affixed to the shaft and operative to receive an input, the input changing an alignment of the shaft;
whereinthe dynamic range module is configured to; receive a first output voltage from a first photodiode of the plurality of photodiodes; receive a second output voltage from a second photodiode of the plurality of photodiodes; compare the first output voltage to the second output voltage to obtain a dynamic range; compare the dynamic range to a target range to determine whether the dynamic range exceeds the target range; and estimate an input current for the light source, wherein the input current is based, at least in part, on the comparison between the dynamic range and the target range and wherein the input current is applied to the light source to dynamically adjust an intensity of the light source to offset the alignment of the shaft when the alignment of the shaft is determined to impact a signal-to-noise ratio of the optical encoder. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification