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Binary Pattern Test Reticle

IP.com Disclosure Number: IPCOM000091949D
Original Publication Date: 1968-Jul-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 29K

Publishing Venue

IBM

Related People

Ett, AH: AUTHOR [+2]

Abstract

This reticle test pattern measures the accuracy of digitally controlled light deflectors such as cathode ray tubes or electro-optic crystal deflectors. The test pattern consists of a set of fiducial marks. Their locations provide a check on the positional accuracy of a light spot deflected by each of a set of binary bits in two axes.

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Binary Pattern Test Reticle

This reticle test pattern measures the accuracy of digitally controlled light deflectors such as cathode ray tubes or electro-optic crystal deflectors. The test pattern consists of a set of fiducial marks. Their locations provide a check on the positional accuracy of a light spot deflected by each of a set of binary bits in two axes.

A reticle for a 12-bit by 12-bit deflector, 4096 x 4096 addressable locations, is shown. The basic arrangement applies to any number of bits. Short vertical and horizontal fiducial marks are located near the X and Y axes of symmetry for the square outline. The square patterns 1, 2, and 3, which coincide over a portion of their boundaries with three of these X and Y fiducial marks, are for checking scaling and distortion in the matrix of addressable locations. The four sets 5, 6, 7, and 8 of three fiducial marks near the center of each quadrant are also used to check distortion and alignment. They are useful for identifying any hysteresis or nonlinearity in CRT distortion correction techniques such as used with flat face tubes.

The linear scale of the test reticle can be chosen to suit the application. For example, the outer boundary of the pattern can be chosen to be an inch square. Since this is a line center-to-line center dimension from row or column 1 to row or column 4096, the one inch dimension spans 4095 matrix elements. Each bit in the binary sequence doubles the amount of deflection caused by the previous bit. Thus, to check twelve bits, independent fiducial marks are required at locations corresponding to the following X and Y address locations. Bit No. Matrix Address Bit No. Matrix Address

0 0 7 64

1 1 8 128

2 2 9 256

3 4 10 512

4 8 11 1024

5 16 12 2048

6 32. Fiducial marks corresponding to these bits are shown by...