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US 2023/0411928 A1Published application
Optical element displacement detection circuit
AssigneeSTMicroelectronics (Research & Development) Limited
InventorsSteven COLLINS, Graeme STORM, Supriya Raveendra HEGDE
Life of this patent
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Abstract
An optical element is positioned in a holder over a laser light source. The optical element includes an electrical trace that is coupled between first and second pads. A sensing circuit that is also coupled to the first and second pads performs a voltage/current sensing operation to detect displacement of the optical element and control enablement of the laser light source.
Claims31
An optical device, comprising:
- an optical element positioned over a laser light source;
- a driver circuit configured to drive said laser light source in response to an enable signal;
- a conductive trace provided at said optical element, where the conductive trace is coupled between a first pad and a second pad;
- and
- a sensing circuit comprising:
- a first current source configured to source a first current to a first resistive divider circuit which includes said conductive trace;
- a second current source configured to source a second current to a second resistive divider circuit configured to output a high reference voltage and a low reference voltage;
- a first comparator circuit having a first input coupled to receive a voltage at the first pad and a second input coupled to receive the high reference voltage;
- a second comparator circuit having a first input coupled to receive a voltage at the second pad and a second input coupled to receive the low reference voltage;
- and
- a combinational logic circuit configured to logically combine digital signals output from the first and second comparator circuits to generate said enable signal.
8 more elements
An optical device, comprising:
- an optical element positioned over a laser light source;
- a driver circuit configured to drive said laser light source in response to an enable signal;
- a conductive trace provided at said optical element, where the conductive trace is coupled between a first pad and a second pad;
- and
- a sensing circuit comprising:
- a current source configured to source a current to the first pad;
- a current comparator circuit configured to compare a sensed current output from the second pad to at least one reference current;
- a differential amplifier configured to a sense a difference in voltage between the first and second pads;
- a voltage comparator circuit configured to compare the sensed difference in voltage to at least one reference voltage;
- and
- a combinational logic circuit configured to logically combine digital signals output from the current and voltage comparator circuits to generate said enable signal.
8 more elements
A sensing circuit, comprising:
- a first current source configured to source a first current to a first resistive divider circuit which includes a first pad and a second pad configured for connection to a conductive trace provided at an optical element;
- a second current source configured to source a second current to a second resistive divider circuit configured to output a high reference voltage and a low reference voltage;
- a first comparator circuit having a first input coupled to receive a voltage at the first pad and a second input coupled to receive the high reference voltage;
- a second comparator circuit having a first input coupled to receive a voltage at the second pad and a second input coupled to receive the low reference voltage;
- and
- a combinational logic circuit configured to logically combine digital signals output from the first and second comparator circuits to generate an enable signal for controlling actuation of a light source that outputs a light beam passing through said optical element.
3 more elements
A sensing circuit, comprising:
- a current source configured to source a current to a first pad configured for connection to a conductive trace provided at an optical element;
- a current comparator circuit configured to receive a sensed current generated from a second pad configured for connection to said conductive trace provided at the optical element and compare the sensed current to at least one reference current;
- a differential amplifier configured to a sense a difference in voltage between the first and second pads;
- a voltage comparator circuit configured to compare the sensed difference in voltage to at least one reference voltage;
- and
- a combinational logic circuit configured to logically combine digital signals output from the current and voltage comparator circuits to generate an enable signal for controlling actuation of a light source that outputs a light beam passing through said optical element.
3 more elements
Dependencies are inferred from the claim text.