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METHOD TO LENGTHEN THE TOTAL CONJUGATE OF FAST GRADIENT INDEX ARRAYS

IP.com Disclosure Number: IPCOM000025706D
Original Publication Date: 1987-Jun-30
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 73K

Publishing Venue

Xerox Disclosure Journal

Abstract

It is well known that rays within a gradient-index lens array travel sinusoidally with a period of 2n/dA where A is the gradient constant defined by the radial gradient equation, where r is the radial distance from the axis of the rod lens and no is the axial refractive index.

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XEROX DISCLOSURE JOURNAL

METHOD TO LENGTHEN THE TOTAL CONJUGATE OF FAST GRADIENT INDEX ARRAYS James D. Rees

Proposed Classification US. C1.350/96.25
Int. C1. G02b 6/06

It is well known that rays within a gradient-index lens array travel sinusoidally with a period of 2n/dA where A is the gradient constant defined by the radial gradient equation,

where r is the radial distance from the axis of the rod lens and no is the axial refractive index.

The total conjugate of such a lens array is typically given as:

(2)

TC = n dA +L, [n<d*L<2nj

where L is the length of the rod lens. Clearly from the constraint dAL < 2n, rays within the rod lens do not complete one period because L<2n / dAL. Present commercial gradient index lens arrays, manufactured by Nippon Sheet Glass Co., Ltd. use the trade name of SELFOC Lens Arrays such that L< 2n / dAL

The radiometric speed3 of a SELFOC lens array is proportional to the value of
A. Increasing A is the principal method used by Nippon Sheet Glass Co. to produce radiometrically fast SELFOC lens arrays for printing and scanning purposes (SLA12,20,25). In producing these lenses it is advisable to keep the AL about constant for efficiency and image quality reasons. Then, from Equation (21, as dA increases and the radiometric speed increases, the total conjugate decreases. This is seen in the TC values of SLA 12, 20, 25 lens arrays. Their total conjugates are typically about 31 mm, 18 mm, and 14 mm, respectively.

When high radiometric speed...