GB907952A - Improvements in method of forming optical image transmitting devices - Google Patents

Abstract

907,952. Optical transfer devices. AMERICAN OPTICAL CO. March 15, 1961, No. 9556/61. Class 97 (1). A method of forming an optical image transfer device comprises the steps of (see Fig. 4) winding from continuous thread-like light conducting fibres a plurality of individually identical hooplike members 32 each in the form of a helix, the convolutes 14 thereof being secured together over a limited area 42, forming a stacked assembly of said hooplike members with parts 42 superimposed and with the respective convolutes parallel, bonding the parts 42 together to form a unitary structure and severing through the joined areas. As shown in Fig. 1 a glass or plastic rod which may consist of a series of fibres is heated at 12 and drawn out into a thin thread 14 which is passed through a bath 22 where it is coated with a substance of lowrefractive index, e.g. tetra-ethyl-ortho-silicate and silica or polyvinyl silicate, and is then wound round a drum 30 to form a hoop 32 which may be several fibres deep. The drum is waxed except for a removable part 34 so that when 34 is removed from the drum the hoop 32 is removed also. The final product can be dipped in the coating bath 22 so that it need not be used at this stage. The width of the hoop 32 is either the width required or the hoop or the assembly of hoops may be cut in a direction parallel to the convolutes to the required width. While the assembly is being formed the hoops 32 may be placed with parts 42 in a holder 44. The holder 44 may be waxed so that it can be removed or it may be stuck on to the hoops and finally'cut with them, in which case it is formed so that it can support lens holders and the like. The assembly may be placed in a bath of, for example, epoxy resin so that the convolutes are stuck together over its entire length and it is therefore relatively rigid.