Ranging sensor, method for driving the same, and ranging module
Ranging sensors with reduced cyclic errors and drive current dispersion are disclosed. In one example, a ranging sensor includes a phase shift circuit that generates a phase-shifted drive pulse signal by shifting a drive pulse signal to a plurality of phases in a time division manner within one frame period, with the drive pulse signal being generated in response to a light emission control signal indicating an irradiation timing of a light emission source. A pixel accumulates electric charges on the basis of the phase-shifted drive pulse signal and outputs a detection signal corresponding to the accumulated electric charges, with the electric charges being obtained by photoelectrically converting reflected light by a predetermined object. The technology can be applied to a ranging module or the like that measures a distance to a predetermined object, for example.
1 . A ranging sensor comprising:
a pixel array including pixels two-dimensionally arranged in a matrix, wherein the pixels respectively include:
a photoelectric conversion portion that photoelectrically converts reflected light,
a first charge storage portion that accumulates electric charges on a basis of a phase-shifted drive pulse signal, and
a second charge storage portion that accumulates the electric charges on a basis of a signal obtained by reversing a phase with respect to the phase-shifted drive pulse signal;
a phase shift circuit that generates the phase-shifted drive pulse signal by shifting a drive pulse signal to at least three phases in a time division manner within one frame period, the drive pulse signal being generated in response to a light emission control signal indicating an irradiation timing of a light emission source; and
wherein the pixels respectively accumulate the electric charges on a basis of the phase-shifted drive pulse signal and output a detection signal corresponding to the accumulated electric charges, the electric charges being obtained by photoelectrically converting reflected light that is reflected by a target object reflecting light emitted from the light emission source.
2 . The ranging sensor according to claim 1 , wherein the phase shift circuit shifts the drive pulse signal to a first phase at a first timing within one frame period, and shifts the drive pulse signal to a second phase at a second timing.
3 . The ranging sensor according to claim 2 , wherein a first period during which the phase-shifted drive pulse signal shifted to the first phase is generated differs from a second period during which the phase-shifted drive pulse signal shifted to the second phase is generated.
4 . The ranging sensor according to claim 1 , wherein
the phase shift circuit is one of at least two phase shift circuits, including a first phase shift circuit and a second phase shift circuit,
wherein the first phase shift circuit generates the phase-shifted drive pulse signal to be supplied to a respective pixel in a first region of the pixel array, and
the second phase shift circuit generates the phase-shifted drive pulse signal to be supplied to the respective pixel in a second region different from the first region of the pixel array.
5 . The ranging sensor according to claim 4 , wherein a phase to be shifted by the first phase shift circuit and a phase to be shifted by the second phase shift circuit differ from each other at least during part of one frame period.
6 . The ranging sensor according to claim 4 , wherein a phase to be shifted by the first phase shift circuit and a phase to be shifted by the second phase shift circuit differ from each other during one entire frame period.
7 . The ranging sensor according to claim 4 , wherein each of the first region and the second region includes at least one pixel column.
8 . The ranging sensor according to claim 4 , wherein each of the first region and the second region includes a plurality of pixel columns.
9 . The ranging sensor according to claim 4 , wherein the first region and the second region are located to divide the pixel array in a vertical direction.
10 . The ranging sensor according to claim 4 , wherein the first region and the second region are arranged in a checkered pattern.
11 . The ranging sensor according to claim 4 , wherein a phase to be shifted by the first phase shift circuit and a phase to be shifted by the second phase shift circuit are in an orthogonal relation.
12 . The ranging sensor according to claim 1 , further comprising a pulse generation circuit that generates the drive pulse signal on a basis of the light emission control signal, and supplies the drive pulse signal to the phase shift circuit.
13 . The ranging sensor according to claim 1 , further comprising a control circuit that controls a timing at which the phase shift circuit changes a phase of the phase-shifted drive pulse signal.
14 . The ranging sensor according to claim 1 , further comprising
a light emission control unit that generates the light emission control signal, and supplies the light emission control signal to the light emission source.
15 . The ranging sensor according to claim 1 , which is formed with one chip in which a plurality of dies is stacked.
16 . A ranging module comprising:
a light emission source that emits light onto a target object at an irradiation timing based on a light emission control signal; and
a ranging sensor that receives reflected light that is reflected by the target object reflecting the light emitted from the light emission source,
wherein the ranging sensor includes:
a pixel array including pixels two-dimensionally arranged in a matrix, wherein the pixels respectively include:
a photoelectric conversion portion that photoelectrically converts reflected light,
a first charge storage portion that accumulates electric charges on a basis of a phase-shifted drive pulse signal, and
a second charge storage portion that accumulates the electric charges on a basis of a signal obtained by reversing a phase with respect to the phase-shifted drive pulse signal;
a phase shift circuit that generates the phase-shifted drive pulse signal by shifting a drive pulse signal to at least three phases in a time division manner within one frame period, the drive pulse signal being generated in response to a light emission control signal indicating an irradiation timing of the light emission source; and
wherein the pixels respectively accumulate electric charges on a basis of the phase-shifted drive pulse signal and output a detection signal corresponding to the accumulated electric charges, the electric charges being obtained by photoelectrically converting the reflected light.
17 . The ranging module according to claim 16 , wherein the phase shift circuit shifts the drive pulse signal to a first phase at a first timing within one frame period, and shifts the drive pulse signal to a second phase at a second timing.
18 . The ranging module according to claim 17 , wherein a first period during which the phase-shifted drive pulse signal shifted to the first phase is generated differs from a second period during which the phase-shifted drive pulse signal shifted to the second phase is generated.