Time of flight sensor capable of compensating temperature deviation and temperature compensation method thereof
AssigneePixart Imaging Inc.
InventorsTso-Sheng TSAI, Yueh-Lin CHUNG, Shin-Lin WANG
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Abstract
There is provided a time of flight sensor including a light source, a first pixel, a second pixel and a processor. The first pixel generates a first output signal without receiving reflected light from an external object illuminated by the light source. The second pixel generates a second output signal by receiving the reflected light from the external object illuminated by the light source. The processor calculates deviation compensation and deviation correction associated with temperature variation according to the first output signal to accordingly calibrate a distance calculated according to the second output signal.
Claims21
A time-of-flight (TOF) sensor, comprising:
- a light source, configured to illuminate light according to a light source driving signal;
- a light sensor, comprising:
- a first pixel, configured to receive a sampling signal,
- generate, at a reference temperature, a first reference output signal when the sampling signal and the light source driving signal have a first time delay therebetween, and generate a second reference output signal when the sampling signal and the light source driving signal have a second time delay therebetween, and
- generate, at an operating temperature, a first operation output signal when the sampling signal and the light source driving signal have the first time delay therebetween, and generate a second operation output signal when the sampling signal and the light source driving signal have the second time delay therebetween;
- and
- a second pixel, configured to receive the sampling signal, and
- generate an operation detected signal at the operating temperature when the sampling signal and the light source driving signal have the first time delay therebetween;
- and
- a processor, configured to
- obtain a first reference phase-distance relationship according to the first reference output signal and the second reference output signal, and obtain an operation phase-distance relationship according to the first operation output signal and the second operation output signal,
- calculate a temperature compensation and a temperature correction according to the first reference phase-distance relationship and the operation phase-distance relationship, and
- calibrate a current phase obtained according to the operation detected signal using the temperature compensation and the temperature correction.
A time-of-flight (TOF) sensor, comprising:
- a light source, configured to illuminate light according to a light source driving signal;
- a light sensor, comprising a first pixel and a second pixel configured to generate output signals according to a sampling signal;
- a memory, configured to previously record
- a first reference phase-distance relationship associated with the first pixel at a reference temperature, and
- a detection compensation and a detection correction that are obtained according to a second reference phase-distance relationship associated with the second pixel at the reference temperature;
- and
- a processor configured to, at an operating temperature,
- calculate an operation phase-distance relationship associated with the first pixel,
- calculate a temperature compensation and a temperature correction according to the first reference phase-distance relationship and the operation phase-distance relationship, and
- calibrate a current distance using the temperature compensation, the temperature correction, the detection compensation and the detection correction.
A temperature compensation method of a time of flight (TOF) sensor, the TOF sensor comprising a time controller, a first delay circuit, a second delay circuit, a first pixel, a second pixel and a light source, the first delay circuit being coupled to the light source, and the second delay circuit being coupled to the first pixel and the second pixel, the temperature compensation method comprising:
- generating, by the time controller, a timing signal to the first delay circuit and the second delay circuit, and setting the first delay circuit and the second delay circuit to sequentially have a first time delay and a second time delay;
- generating a first reference output signal by the first pixel at a reference temperature and the first time delay;
- generating a second reference output signal by the first pixel at the reference temperature and the second time delay;
- obtaining and recording a first reference phase-distance relationship according to the first reference output signal and the second reference output signal;
- generating a first operation output signal by the first pixel at an operating temperature and the first time delay;
- generating a second operation output signal by the first pixel at the operating temperature and the second time delay;
- obtaining an operation phase-distance relationship according to the first operation output signal and the second operation output signal;
- calculating a temperature compensation and a temperature correction according to the first reference phase-distance relationship and the operation phase-distance relationship;
- and
- calibrating a current phase obtained according to an operation detected signal generated by the second pixel at the operating temperature using the temperature compensation and the temperature correction.
A time-of-flight sensor, comprising:
- an encapsulation comprising a first accommodation space and a second accommodation space, wherein the first accommodation space is connected to a first opening and covered by a top cover surrounding the first opening, and the second accommodation space is connected to a second opening;
- a light source arranged in the first accommodation space;
- a first pixel, arranged in the first accommodation space, and configured to receive reflected light projected by the light source to the top cover;
- and
- a second pixel, arranged in the second accommodation space, and configured to receive reflected light formed by emission light projected by the light source to penetrate the first opening of the first accommodation space, reflected by an external object, and then penetrating the second opening of the second accommodation space.
Dependencies are inferred from the claim text.