Distance sensor and distance measurement device

Abstract

There is provided a time of flight sensor. The time of flight sensor includes a light receiving element PD, a first signal line TRGO and a second signal line TRG, a first transistor TGA in electrical communication with the light receiving element, the first transistor comprising a first gate in electrical communication with the first signal line TRGO, a second transistor TGB in electrical communication with the light receiving element, the second transistor comprising a second gate in electrical communication with the second signal line TRG, and a control circuit Pcomprising at least one comparatorA,B, wherein the control circuit is in electrical communication with the first and second signal lines TRGO, TRG. The transistors TGA and TGB of the pixel circuit Pare turned on and off so that any one of the transistors TGA and TGB is turned on, and the electric charges generated by the photodiode PD are selectively accumulated at the floating diffusion FDA and the floating diffusion FDB. First and second voltages VSLA, VSLB depending on voltages at first and second floating diffusions FDA, FDB, respectively, are compared to a reference voltage VREF. The first signal TRGO is a logical product of a clock signal SCK and the comparator output QO, and the second signal TRGis the logical product of the inverted clock signal SCK and the comparator output QO. A distance measurement device has an imaging unit including a pixel array of a plurality of imaging pixels P arranged in a matrix. One control circuit Pis provided for one pixel circuit P. The control circuit Pcontrols the exposure time in the pixel circuit P. The pixel circuit Psupplies the voltages VSLA and VSLB to the control circuit P, and the control circuit Pgenerates the signals TRGO and TRGon the basis of the voltages VSLA and VSLB, and supplies these signals TRGO and TRGto the pixel circuit P. Thus, since the exposure time can be individually set in each of the plurality of imaging pixels, the measurement accuracy in distance measurement can be enhanced.