Optics: measuring and testing – Range or remote distance finding – With photodetection
Reexamination Certificate
2000-10-27
2002-06-04
Buczinski, Stephen C. (Department: 3662)
Optics: measuring and testing
Range or remote distance finding
With photodetection
C356S141100, C180S169000
Reexamination Certificate
active
06400448
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a photo detecting device. In addition, this invention relates to a distance measuring apparatus. Furthermore, this invention relates to a distance and image measuring apparatus.
2. Description of the Related Art
There is a conventional distance measuring apparatus mounted on a vehicle. The conventional apparatus intermittently emits a laser beam into a predetermined angular range outside the body of the vehicle. The predetermined angular range is scanned by the laser beam. Thus, the predetermined angular range is also referred to as the scanned range. When an object in the scanned range reflects the laser beam, a portion of the laser beam returns to the apparatus as an echo. The apparatus measures the time difference between the timing of the emission of the laser beam and the timing of the reception of the echo. The apparatus calculates the distance to the object on the basis of the measured time difference. The scanned range corresponds to a detection area. Basically, it is desirable to provide a wide scanned range, that is, a wide detection area.
When the scanned range is excessively wide, the following problems arise. The apparatus on the present vehicle receives a laser beam emitted from an apparatus on another vehicle running on the opposite lane. The received laser beam interferes with a distance measurement by the apparatus on the present vehicle. The apparatus on the present vehicle receives an echo related to an apparatus on another vehicle running on an adjacent lane. The received echo interferes with a distance measurement by the apparatus on the present vehicle.
U.S. Pat. No. 5,760,886 corresponding to Japanese published unexamined patent application 7-98381 discloses a scanning-type distance measurement device which is responsive to selected signals to reduce interference due to stray light. An emitted beam of light is aimed to be reflected from an object toward a photodetector among a plurality of photodetectors which are positioned linearly or in two dimensions. The outputs of the photodetectors are selected based on the position of the emitted beam of light to ignore photodetectors which should not contribute to the reflected beam. The approach in U.S. Pat. No. 5,760,886 reduces the effects of stray noise from other light sources. The selection of the photodetectors is synchronized with a scanning light emitter by a position signal and an angular signal so that the noise component in the output signal can be kept to a minimum.
In the device of U.S. Pat. No. 5,760,886, a switch is provided between a timing circuit and an array of photodetectors. The switch selects one from among the photodetectors, and transmits the output signal of the selected photodetector to the timing circuit. A possible problem in the device of U.S. Pat. No. 5,760,886 is as follows. The output signals of the non-selected photodetectors leak to the timing circuit through the switch. Therefore, in the case where a non-selected photodetector receives stray light, a noise signal leaks therefrom to the timing circuit. In this case, the timing circuit responds to the noise signal.
SUMMARY OF THE INVENTION
It is a first object of this invention to provide an improved photo detecting device.
It is a second object of this invention to provide an improved distance measuring apparatus.
It is a third object of this invention to provide an improved distance and image measuring apparatus.
A first aspect of this invention provides a photo detecting device comprising a processing circuit; an output line leading to the processing circuit; a ground line; an array of pixels including respective photo detecting zones for changing incident light into corresponding electric signals through photoelectric conversion, wherein each of the pixels includes a first switch for selectively connecting and disconnecting a related photo detecting zone to and from the output line, and a second switch for selectively connecting and disconnecting the related photo detecting zone to and from the ground line; means for causing the second switch to disconnect the related photo detecting zone from the ground line when the first switch connects the related photo detecting zone to the output line; and means for causing the second switch to connect the related photo detecting zone to the ground line when the first switch disconnects the related photo detecting zone from the output line.
A second aspect of this invention is based on the first aspect thereof, and provides a photo detecting device wherein the photo detecting zone of each of the pixels comprises a pin photodiode, and the first and second switches are formed in well layers separate from the photo detecting zone.
A third aspect of this invention is based on the first aspect thereof, and provides a photo detecting device further comprising a matrix arrangement of pixels provided in the array of pixels, common lines provided in the output line, wherein pixels in one of one-direction pixel groups in the matrix arrangement are connected to one of the common lines, a third switch for selectively connecting and disconnecting one of the common lines to and from the processing circuit, a fourth switch for selectively connecting and disconnecting one of the common lines to the ground line, means for causing the fourth switch to disconnect the related common line from the ground line when the third switch connects the related common line to the processing circuit, and means for causing the fourth switch to connect the related common line to the ground line when the third switch disconnects the related common line from the processing circuit.
A fourth aspect of this invention is based on the third aspect thereof, and provides a photo detecting device further comprising first control lines each for controlling the first switches in one of row-direction pixel groups in the matrix arrangement, second control lines each for controlling the second switches in one of the row-direction pixel groups in the matrix arrangement, a third control line for controlling the third switch, and a fourth control line for controlling the fourth switch.
A fifth aspect of this invention is based on the first aspect thereof, and provides a photo detecting device further comprising a capacitor provided in each of the pixels for storing electric charges generated by the related photo detecting zone in response to the incident light, an image-signal output line leading to the processing circuit, a fifth switch provided in each of the pixels for selectively connecting and disconnecting the photo detecting zone to and from the capacitor, a sixth switch for selectively connecting and disconnecting the capacitor to and from the image-signal output line, the second switch being for selectively connecting and disconnecting the capacitor to and from the ground line, and means for causing the second switch to connect the capacitor to the ground line during a predetermined time interval after causing the sixth switch to connect the capacitor to the image-signal output line.
A sixth aspect of this invention is based on the fifth aspect thereof, and provides a photo detecting device further comprising a matrix arrangement of pixels provided in the array of pixels, common image-signal lines provided in the image-signal output line, wherein pixels in one of one-direction pixel groups in the matrix arrangement are connected to one of the common image-signal lines, and a seventh switch for selectively connecting and disconnecting one of the common image-signal lines to and from the processing circuit.
A seventh aspect of this invention provides a photo detecting device comprising a processing circuit; a matrix arrangement of pixels including respective photo detecting zones for changing incident light into corresponding electric signals through photoelectric conversion; common output lines leading to the processing circuit and each provided for pixels in one of one-direction pixel groups in the matrix arrangement; a ground line; a first switch
Sano Naoki
Sugawara Ryoichi
Buczinski Stephen C.
Law Offices of David G. Posz
LandOfFree
Photo detecting device, distance measuring apparatus, and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photo detecting device, distance measuring apparatus, and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photo detecting device, distance measuring apparatus, and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2915911