Imaging devices with optical shutters and low-power drivers therefor

Abstract

An imaging device includes at least a first group of pixels. A driver block is configured to generate at least two shutter signals, each having on-phases periodically alternating with off-phases. The shutter signals might not be in phase. The imaging device may have an optical shutter that is partitioned in two or more parts, or a set of two or more optical shutters. The shutter parts, or the shutters, may receive the shutter signals, and accordingly open and close. A design of the driver block requires reduced power, which is highly desirable for mobile applications. Moreover, 3D imaging may be implemented that uses various time-of-flight configurations.

1 . An imaging device comprising:
 a casing with an opening;   a driver block configured to generate a first shutter signal having on-phases periodically alternating with off-phases, and a second shutter signal having on-phases periodically alternating with off-phases, the on-phases of the first shutter signal not in phase with the on-phases of the second shutter signal;   an optical shutter within the casing, the optical shutter having a first shutter part and a second shutter part distinct from the first shutter part, the first shutter part being driven by the first shutter signal to alternatingly open and close responsive to the on-phases and to the off-phases respectively of the first shutter signal, the second shutter part being driven by the second shutter signal to alternatingly open and close responsive to the on-phases and to the off-phases respectively of the second shutter signal; and   a first group of pixels positioned within the casing so as to start receiving light through the opening responsive to the first shutter part opening.   
     
     
         2 . The imaging device of  claim 1 , further comprising:
 a second group of pixels positioned within the casing so as to start receiving light through the opening responsive to the second shutter part opening.   
     
     
         3 . The imaging device of  claim 2 , in which
 the first group of pixels and the second group of pixels are arranged within a single pixel array.   
     
     
         4 . The imaging device of  claim 2 , in which
 the first group of pixels and the second group of pixels are arranged within different respective pixel arrays.   
     
     
         5 . The imaging device of  claim 1 , in which
 the on-phases of the first shutter signal are substantially out of phase from the on-phases of the second shutter signal.   
     
     
         6 . The imaging device of  claim 1 , in which
 the driver block includes bias circuits arranged together as a latch.   
     
     
         7 . The imaging device of  claim 1 , in which
 the driver block generates the first shutter signal and the second shutter signal at a first and at a second nodes, and   the driver block includes an inductor coupled between the first and the second nodes.   
     
     
         8 . The imaging device of  claim 1 , further comprising:
 support components in a locked loop configuration such that a voltage control signal is generated responsive to a version of the first shutter signal, and   in which the driver block is configured to receive the voltage control signal.   
     
     
         9 . The imaging device of  claim 8 , in which
 the locked loop configuration is a phase locked loop.   
     
     
         10 . The imaging device of  claim 8 , in which
 the driver block includes a voltage-controlled inductor that is configured to receive the voltage control signal.   
     
     
         11 . The imaging device of  claim 8 , in which
 the driver block includes a voltage-controlled capacitor configured to receive the voltage control signal.   
     
     
         12 . The imaging device of  claim 8 , further comprising:
 a light driver configured to generate a light clock signal responsive to the first shutter signal; and   a light source on the casing configured to transmit, responsive to the light clock signal, modulated light towards an object outside the casing, and   in which the first group of pixels are configured to image reflections of the modulated light from the object.   
     
     
         13 . The imaging device of  claim 12 , in which
 the first group of pixels includes time-of-flight pixels.   
     
     
         14 . The imaging device of  claim 1 , further comprising:
 a light driver configured to generate a light clock signal responsive to the first shutter signal; and   a light source on the casing configured to transmit, responsive to the light clock signal, modulated light towards an object outside the casing, and   in which the first group of pixels are configured to image reflections of the modulated light from the object.   
     
     
         15 . The imaging device of  claim 14 , in which
 the first group of pixels includes time-of-flight pixels.   
     
     
         16 . The imaging device of  claim 15 , in which
 the second group of pixels includes time-of-flight pixels.   
     
     
         17 . The imaging device of  claim 14 , in which
 an operation of the light driver is supported by a delay locked loop.   
     
     
         18 . The imaging device of  claim 14 , further comprising:
 a buffer configured to output a certain clock signal responsive to the first shutter signal, and   in which the light driver generates the light clock signal responsive to the certain clock signal.   
     
     
         19 . The imaging device of  claim 14 , further comprising:
 a phase calibration module configured to generate a phase select signal, and   in which the light driver includes a multiplexer configured to operate responsive to the phase select signal.   
     
     
         20 . The imaging device of  claim 1 , in which
 the driver block is further configured to generate a third shutter signal having on-phases periodically alternating with off-phases, the on-phases of the third shutter signal not in phase with the on-phases of the first shutter signal or with the on-phases of the second shutter signal,   the optical shutter also has a third shutter part distinct from the first shutter part and the second shutter part, the third shutter part being configured to alternatingly open and close responsive to the alternating phases of the third shutter signal.   
     
     
         21 . The imaging device of  claim 20 , in which
 the driver block is further configured to generate a fourth shutter signal having on-phases periodically alternating with off-phases, the on-phases of the fourth shutter signal not in phase with the on-phases of the second shutter signal or with the on-phases of the second shutter signal or with the on-phases of the third shutter signal,   the optical shutter also has a fourth shutter part distinct from the first shutter part, the second shutter part, and the third shutter part, the fourth shutter part being configured to alternatingly open and close responsive to the alternating phases of the fourth shutter signal.   
     
     
         22 . The imaging device of  claim 21 , in which
 the driver block includes at least a first driver unit and a second driver unit distinct from the first driver unit,   the first driver unit generates the first and the third shutter signals in response to receiving the second and the fourth shutter signals, and   the second driver unit generates the second and the fourth shutter signals in response to receiving the first and the third shutter signals.   
     
     
         23 - 27 . (canceled) 
     
     
         28 . An imaging device comprising:
 a casing with an opening;   a driver block configured to generate a first shutter signal having on-phases periodically alternating with off-phases, and a second shutter signal having on-phases periodically alternating with off-phases, the on-phases of the first shutter signal not in phase with the on-phases of the second shutter signal;   a first optical shutter within the casing, the first optical shutter being driven by the first shutter signal to alternatingly open and close responsive to the on-phases and to the off-phases respectively of the first shutter signal; and   a second optical shutter within the casing distinct from the first optical shutter, the second optical shutter being driven by the second shutter signal to alternatingly open and close responsive to the on-phases and to the off-phases respectively of the second shutter signal; and   a first group of pixels positioned within the casing so as to start receiving light through the opening responsive to the first optical shutter opening.   
     
     
         29 - 54 . (canceled)