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Optical Two-Dimensional Position Sensor

IP.com Disclosure Number: IPCOM000039444D
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Strand, T: AUTHOR [+3]

Abstract

A two-dimensional position sensor is described in which a sheet of collimated laser light is incident on the object of interest. The reflection is split by an encoded beam splitter, and collected by two sets of cylindrical lenses and linear charge-coupled devices (CCD). The two-dimensional position sensor comprises (see Fig. 1) a line illumination beam 1 of laser light which is incident on the surface 2 of interest. The light reflected from the surface is imaged along the vertical displacement axis Y' by cylindrical lens 3 onto an encoded beamsplitter, such as a linear wedge neutral density filter (LWNDF) 5. The two relating beams are imaged along the X axis by cylindrical lens 4 onto the two linear CCD systems 7 and 8.

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Optical Two-Dimensional Position Sensor

A two-dimensional position sensor is described in which a sheet of collimated laser light is incident on the object of interest. The reflection is split by an encoded beam splitter, and collected by two sets of cylindrical lenses and linear charge-coupled devices (CCD). The two-dimensional position sensor comprises (see Fig. 1) a line illumination beam 1 of laser light which is incident on the surface 2 of interest. The light reflected from the surface is imaged along the vertical displacement axis Y' by cylindrical lens 3 onto an encoded beamsplitter, such as a linear wedge neutral density filter (LWNDF) 5. The two relating beams are imaged along the X axis by cylindrical lens 4 onto the two linear CCD systems 7 and 8. Since the position of the light at the wedge beam splitter 5 determines the intensity rates reaching the corresponding pixels, the data reduction algorithm is expressed by the following algebraic expression:

(Image Omitted)

where i is the position of the beam on the x-axis in terms of pixel number,

Y is the position of the beam at the y-axis in terms of the

intensity ratio,

V1,i is the voltage output at the ith pixel of array #1,

V2,i is the voltage output at the ith pixel of array #2, and

K2 is the correction factor to compensate for the gain

difference, for the ith pixel, between array #1 and #2. The data reduction algorithm is implemented at the hardware level by the circuit that is shown in block diagram...