Range image acquisition device

1 . A range image acquisition device comprising:

a light source generating a pulsed light;

a light source control unit controlling the light source to repeatedly generate the pulsed light within a periodic frame period;

a pixel array including a plurality of pixel circuit units arranged in N rows and M columns (N and M are integers of 2 or more) and generating electric charges corresponding to a received light; and

a peripheral circuit arranged in a peripheral portion of the pixel array and supplying a control signal controlling an operation of the pixel array to the pixel array,

wherein the pixel circuit unit has: a photoelectric conversion region converting a light into electric charges; first to X-th (X is an integer of 2 or more) charge reading regions provided to be close to the photoelectric conversion region and separated from each other and having a capacitance component for accumulating the electric charges generated in the photoelectric conversion region; a charge discharging region provided to be close to the photoelectric conversion region and for discharging the electric charges generated in the photoelectric conversion region without passing through the charge reading regions; first to X-th control electrodes provided corresponding to the photoelectric conversion region and the first to X-th charge reading regions, respectively, and for applying a transfer control pulse for transfer of the electric charges between the photoelectric conversion region and the first to X-th charge reading regions; and an (X+1)-th control electrode for applying the transfer control pulse for direct transfer of the electric charges between the photoelectric conversion region and the charge discharging region,

wherein the light source control unit repeatedly performs an operation of generating the pulsed light so that a returned light based on the pulsed light is incident on a sensitive region in the pixel array while moving in the sensitive region,

wherein the peripheral circuit supplies the control signal to the pixel array so that the transfer control pulse is applied,

wherein the transfer control pulse transfers the electric charges generated in the photoelectric conversion region in the pixel circuit units constituting the sensitive region to the charge reading region and transfers the electric charges generated in the photoelectric conversion region in the pixel circuit units constituting the insensitive region not included in the sensitive region to the charge discharging region,

wherein the peripheral circuit includes a distribution circuit distributing a control pulse and a pixel switching circuit outputting a logic pulse for setting the pixel circuit unit to be sensitive or insensitive, and

wherein the pixel circuit unit includes first to (X+1)-th driver circuits that perform a logic operation on the control pulse and the logic pulse to generate the transfer control pulse applied to each of the first to (X+1)-th control electrodes.

2 . The range image acquisition device according to claim 1 ,

wherein the light source control unit performs an operation of emitting the pulsed light from the light source so as to expose the sensitive regions of all the pixel circuit units included in a j-th row (j is an integer of 1 or more and N or less), and

wherein the peripheral circuit performs:

an operation of supplying the control signal to the pixel array so that the transfer control pulse permitting the movement of the electric charges from the photoelectric conversion region to the charge reading regions is applied to the first to X-th control electrodes of all the pixel circuit units included in the j-th row; and

an operation of supplying the control signal to the pixel array so that the transfer control pulse permitting the movement of the electric charges from the photoelectric conversion region to the charge discharging region is applied to the (X+1)-th control electrodes of all the pixel circuit units included in the insensitive region.

3 . The range image acquisition device according to claim 1 ,

wherein the light source control unit performs an operation of emitting the pulsed light from the light source so as to expose the sensitive region of a portion of the pixel circuit units included in a j-th row (j is an integer of 1 or more and N or less), and

wherein the peripheral circuit performs:

an operation of supplying the control signal to the pixel array so that the transfer control pulse permitting the movement of the electric charges from the photoelectric conversion region to the charge reading regions is applied to the first to X-th control electrodes included in a portion of the pixel circuit units included in the j-th row; and

an operation of supplying the control signal to the pixel array so that the transfer control pulse permitting the movement of the electric charges from the photoelectric conversion region to the charge discharging region is applied to all the (X+1)-th control electrodes of the pixel circuit units included in the insensitive region.

4 . The range image acquisition device according to claim 1

wherein the peripheral circuit and the light source control unit perform a read operation of outputting a voltage based on the electric charges accumulated in the charge reading regions after performing an exposure operation on the plurality of sensitive regions several times.

5 . The range image acquisition device according to claim 1 ,

wherein the peripheral circuit and the light source control unit repeatedly perform an exposure operation on the selected sensitive region and a read operation outputting a voltage based on the electric charges accumulated in the charge reading regions for the pixel circuit units constituting the selected sensitive region while changing the sensitive region to be selected.

6 . The range image acquisition device according to claim 1 ,

wherein the peripheral circuit and the light source control unit concurrently perform the exposure operation for the sensitive region and the read operation for outputting the voltage based on the electric charges accumulated in the charge reading regions.

7 . The range image acquisition device according to claim 4 , wherein, in the exposure operation, the light source control unit generates the pulsed light only once for the sensitive region.

8 . The range image acquisition device according to claim 4 , wherein, in the exposure operation, the light source control unit generates the pulsed light several times for the sensitive region.

9 . The range image acquisition device according to claim 1 ,

wherein the pixel circuit unit has:

the photoelectric conversion region having a function of converting an incident pulsed light into the electric charges; and

a read circuit receiving the electric charges from the photoelectric conversion region and outputting a voltage based on the electric charges,

wherein the pixel circuit unit is configured to include a plurality of n-type MOS transistors, and

wherein the pixel circuit unit does not include a p-type MOS transistor.

10 . The range image acquisition device according to claim 3 ,

wherein the light source control unit performs an operation of emitting the pulsed light from the light source so as to expose the sensitive region of a portion of the pixel circuit units included in the j-th row (j is an integer of 1 or more and N/R or less (R is the array division number in the row direction)) in the divided pixel array regions obtained by dividing the pixel array into the plurality of regions,

wherein the light source is divided in illumination so as to simultaneously expose the sensitive regions included in all the divided pixel array regions, and

wherein the peripheral circuit performs:

an operation of supplying the control signal to the pixel array so that the transfer control pulse permitting the movement of the electric charges from the photoelectric conversion region to the charge reading regions is applied to the first to X-th control electrodes included in a portion of the pixel circuit units included in the j-th row of all the divided pixel array regions; and

an operation of supplying the control signal to the pixel array so that the transfer control pulse permitting the movement of the electric charges from the photoelectric conversion region to the charge discharging region is applied to all the (X+1)-th control electrodes of the pixel circuit units included in the insensitive regions of all the divided pixel array regions.