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Self-Balancing Position-Sensitive Detector (SBPSD).

Porrazzo R, Lydecker L, Gattu S, Bakhru H, Tokranova N, Castracane J - Sensors (Basel) (2015)

Bottom Line: Fabricated prototype devices demonstrate linear, symmetric coordinate characteristics and a spatial resolution of 200 μm for a 74 mm device.PSDs are commercially available only up to a length of 37 mm.Prototype devices were fabricated with various lengths up to 100 mm and can be scaled down to any size below that.

View Article: PubMed Central - PubMed

Affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12222, USA. rporrazzo@albany.edu.

ABSTRACT
Optical position-sensitive detectors (PSDs) are a non-contact method of tracking the location of a light spot. Silicon-based versions of such sensors are fabricated with standard CMOS technology, are inexpensive and provide a real-time, analog signal output corresponding to the position of the light spot. An innovative type of optical position sensor was developed using two back-to-back connected photodiodes. These so called self-balancing position-sensitive detectors (SBPSDs) eliminate the need for external readout circuitry entirely. Fabricated prototype devices demonstrate linear, symmetric coordinate characteristics and a spatial resolution of 200 μm for a 74 mm device. PSDs are commercially available only up to a length of 37 mm. Prototype devices were fabricated with various lengths up to 100 mm and can be scaled down to any size below that.

No MeSH data available.


Related in: MedlinePlus

Output voltage vs. current measurements for various light positions (A = −0.4 mm, B = −0.2 mm, C = 0 mm, D = 0.2 mm, E = 0.4 mm).
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sensors-15-17483-f007: Output voltage vs. current measurements for various light positions (A = −0.4 mm, B = −0.2 mm, C = 0 mm, D = 0.2 mm, E = 0.4 mm).

Mentions: The location of the light spot was changed similarly to Figure 5, by moving the spot position by 0.2 mm and 0.4 mm in the Y and −Y direction and an I-V curve was measured at each spot location. In the resulting I-V curves (Figure 7), the positive saturation current decreased for all measurements that were not in the center of the device. For the negative saturation current, a noticeable difference was observed; depending on which side of the device the light spot was moved, the current changed in response. When the light spot was offset towards the biased line, the saturation current was more negative (lower) than at the center light position. When the light spot was offset towards the floating line the current was less negative (higher) than the center light position. This change in the I-V response led to a corresponding change in the coordinate characteristic for these devices. The performance measurements confirmed the importance of light positioning on the photosensitive surface of the device for accurate coordinate determination.


Self-Balancing Position-Sensitive Detector (SBPSD).

Porrazzo R, Lydecker L, Gattu S, Bakhru H, Tokranova N, Castracane J - Sensors (Basel) (2015)

Output voltage vs. current measurements for various light positions (A = −0.4 mm, B = −0.2 mm, C = 0 mm, D = 0.2 mm, E = 0.4 mm).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541945&req=5

sensors-15-17483-f007: Output voltage vs. current measurements for various light positions (A = −0.4 mm, B = −0.2 mm, C = 0 mm, D = 0.2 mm, E = 0.4 mm).
Mentions: The location of the light spot was changed similarly to Figure 5, by moving the spot position by 0.2 mm and 0.4 mm in the Y and −Y direction and an I-V curve was measured at each spot location. In the resulting I-V curves (Figure 7), the positive saturation current decreased for all measurements that were not in the center of the device. For the negative saturation current, a noticeable difference was observed; depending on which side of the device the light spot was moved, the current changed in response. When the light spot was offset towards the biased line, the saturation current was more negative (lower) than at the center light position. When the light spot was offset towards the floating line the current was less negative (higher) than the center light position. This change in the I-V response led to a corresponding change in the coordinate characteristic for these devices. The performance measurements confirmed the importance of light positioning on the photosensitive surface of the device for accurate coordinate determination.

Bottom Line: Fabricated prototype devices demonstrate linear, symmetric coordinate characteristics and a spatial resolution of 200 μm for a 74 mm device.PSDs are commercially available only up to a length of 37 mm.Prototype devices were fabricated with various lengths up to 100 mm and can be scaled down to any size below that.

View Article: PubMed Central - PubMed

Affiliation: Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12222, USA. rporrazzo@albany.edu.

ABSTRACT
Optical position-sensitive detectors (PSDs) are a non-contact method of tracking the location of a light spot. Silicon-based versions of such sensors are fabricated with standard CMOS technology, are inexpensive and provide a real-time, analog signal output corresponding to the position of the light spot. An innovative type of optical position sensor was developed using two back-to-back connected photodiodes. These so called self-balancing position-sensitive detectors (SBPSDs) eliminate the need for external readout circuitry entirely. Fabricated prototype devices demonstrate linear, symmetric coordinate characteristics and a spatial resolution of 200 μm for a 74 mm device. PSDs are commercially available only up to a length of 37 mm. Prototype devices were fabricated with various lengths up to 100 mm and can be scaled down to any size below that.

No MeSH data available.


Related in: MedlinePlus