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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

Schematic drawing of light spot position.
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sensors-15-17483-f005: Schematic drawing of light spot position.

Mentions: To investigate this effect, 37 mm-long devices fabricated with a metal line connecting the contact pads for doped lines while bare silicon connected the other doped lines were used for testing (Figure 5). Testing was performed by moving the light spot incrementally by an offset in the vertical direction by 0.2 mm from the center, and the same measurement was performed. The light spot was further offset 0.2 mm to the left for a total of 0.4 mm from the center light spot and a coordinate plot was measured (Figure 5). The same measurement was then performed on the bottom portion of the device at 0.2 mm and 0.4 mm from the center. In Figure 6, points E and F are positioned identically with reference to the light spot, with the only difference being which line the 0 to 5 V bias was applied to. Point E clearly demonstrates that application of a bias onto the metal line achieved a linear profile compared to the curved profile in point F, where the bias was placed on the side with no metal line connecting the contacts. A metal line connecting the contact pads across the device led to fewer losses when compared to a nonmetal line. Lateral displacement in the light spot from the nonmetal to the metal causes the resistance in the nonmetal to decrease, leading to a more linear coordinate plot.


Self-Balancing Position-Sensitive Detector (SBPSD).

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

Schematic drawing of light spot position.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-17483-f005: Schematic drawing of light spot position.
Mentions: To investigate this effect, 37 mm-long devices fabricated with a metal line connecting the contact pads for doped lines while bare silicon connected the other doped lines were used for testing (Figure 5). Testing was performed by moving the light spot incrementally by an offset in the vertical direction by 0.2 mm from the center, and the same measurement was performed. The light spot was further offset 0.2 mm to the left for a total of 0.4 mm from the center light spot and a coordinate plot was measured (Figure 5). The same measurement was then performed on the bottom portion of the device at 0.2 mm and 0.4 mm from the center. In Figure 6, points E and F are positioned identically with reference to the light spot, with the only difference being which line the 0 to 5 V bias was applied to. Point E clearly demonstrates that application of a bias onto the metal line achieved a linear profile compared to the curved profile in point F, where the bias was placed on the side with no metal line connecting the contacts. A metal line connecting the contact pads across the device led to fewer losses when compared to a nonmetal line. Lateral displacement in the light spot from the nonmetal to the metal causes the resistance in the nonmetal to decrease, leading to a more linear coordinate plot.

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