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US 10,380,445 B2Granted
Optical encoder capable of identifying absolute positions and operating method thereof
AssigneePixart Imaging Inc.
InventorsWai-Lian Teo, Yen-Min Chang
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Abstract
The present disclosure is related to an optical encoder which is configured to provide precise coding reference data by feature recognition technology. To apply the present disclosure, it is not necessary to provide particular dense patterns on a working surface. The precise coding reference data can be generated by detecting surface features of the working surface.
Claims20
An optical encoder, comprising:
- an optical navigation chip, comprising:
- a light sensing unit having a plurality of pixels arranged in a matrix, the plurality of pixels configured to detect a marker at a reference position on a detection surface arranged opposite to the light sensing unit, to capture an image, wherein the marker has patterned lines each formed between a first blackness region and a second blackness region of the marker;
- and
- a processing unit connected to the light sensing unit to receive the image, and configured to generate a pulse width modulated (PWM) signal corresponding to the marker at the reference position on the detection surface, wherein the PWM signal has two signal levels each has a pulse width corresponding to a pixel distance between two detected lines in the captured image or between an edge of the captured image and one detected line in the captured image;
- and
- a pin arranged outside the optical navigation chip and connected to the processing unit, the pin configured to output the PWM signal to a back-end circuit for determining a current angle of the marker with respect to the detection surface.
3 more elements
An optical encoder, comprising:
- a displacement generating unit having a detection surface formed with a plurality of markers at different reference positions, each of the markers having patterned lines each formed between a first blackness region and a second blackness region of the marker;
- an optical navigation module comprising:
- a light sensing unit configured to detect the markers to capture an image;
- and
- a processing unit configured to output, in a comparison mode, a pulse width modulated (PWM) signal corresponding to the markers at the different reference positions on the detection surface, wherein the PWM signal has two signal levels each has a pulse width corresponding to a pixel distance between two detected lines in the captured image or between an edge of the captured image and one detected line in the captured image;
- and
- a back-end circuit comprising:
- a memory configured to store predetermined PWM signals corresponding to the plurality of markers at the different reference positions;
- and
- a microcontroller configured to compare the outputted PWM signal with the predetermined PWM signal to determine a current position of the optical navigation module with respect to the detection surface.
7 more elements
An operating method of an optical encoder, the optical encoder comprising a light sensing unit for capturing an image of a marker, the operating method comprising:
- storing, in a registration mode, a predetermined pulse width modulated (PWM) signal corresponding to the marker at a reference position on a detection surface in a memory;
- and
- comparing, in a comparison mode, a current PWM signal with the predetermined PWM signal to determine a current position with respect to the detection surface,
- wherein the predetermined PWM signal and the current PWM signal have two signal levels each has a pulse width corresponding to a pixel distance between two detected lines, each of which is associated with a patterned line which is formed between a first blackness region and a second blackness region of the marker, in a captured image from the light sensing unit or between an edge of the captured image and one detected line in the captured image.
1 more element
Dependencies are inferred from the claim text.