Patent GB-1207814-A (GB)
Title: Method of producing a fiber-optics image-transmitting device
IPC: C03B37/14
Filed: 1967-11-27
Abstract: 1,207,814. Sealing glass fibres for optical image transmitting devices. CARL ZEISSSTIFTUNG, [trading as CARL ZEISS]. 27 Nov., 1967 [1 Dec., 1966 (2)], No. 53935/67. Heading C1M. In a method of producing a fibre optics imagetransmitting device from a bundle composed of a plurality of light-conducting core-sheath fibres, the fibres in the bundle are held together at one end, the free end of the bundle immersed lengthwise in a wetting liquid and withdrawn in a vertical direction, and the free end of the bundle fixed to cause the fibres to permanently adhere to each other. In one embodiment a bundle of light conducting fibres 1 is held at one end by a ring 4. The bundle is then immersed over substantially the whole of its length in a bath 3 of a wetting liquid, e.g. water, the bundle being lowered through a diaphragm 9 having a hexagonal opening. To assist in aligning the fibres an ultrasonic generator 8 may be immersed in the bath 3, and also the diaphragm 9 may be attached to a vibrator 10. The bundle is vertically drawn out of the bath through the diaphragm 9 (now stationary) and takes the shape of the diaphragm opening. The diaphragm aids in removing the excess wetting liquid. The bundle of fibres is now reversed so that the end previously held in the ring 4 is immersed in the wetting liquid. The ends are then fixed in a resin hardener. It is preferred that the diaphragm comprises a series of spring loaded plates (one to define each side of the opening) positioned by a cam surface to give orifices of given dimensions, and so that as the fibre bundle is withdrawn through the diaphragm, the sides thereof exert a small, but positive pressure on the fibres of the bundle. In another embodiment the alignment of the fibres is achieved by their immersion in a bath in which the wetting liquid is caused to flow along the surface of the fibres in the bundle. Again after wetting, the ends of the bundle are fixed. In further embodiments described (but not shown) the fibres are aligned by being held in a stem, of dimension not substantially greater than that of the fibre bundle, of a wetting vessel, the liquid being caused to flow downwardly through the stem; or they are passed through a multiple grid system whereby the superimposition of the several grids causes each fibre, or a very small number of fibres, to be separate from the adjacent fibre or fibres. Further an inverted frusto-conical diaphragm may be used. In yet a further embodiment the fibre bundle is immersed in a bath of water and withdrawn upwardly through a diaphragm 48 and thence through a cooling tube 49 (Fig. 8) in which the water is caused to freeze thus rigidly separating the fibres. The frozen bundle is then placed in a vacuum vessel and a pressure of 0.1 to 1 torr produced. The ice sublimates and after this has occurred the free end of the bundle is dipped into a resin hardener contained within the vacuum chamber. When that end has been fixed the bundle is held by that end and the process repeated so that the other end may be fixed. Whilst the above only describes the fixing of the ends of the bundle, whereby a light-conducting device having correctly orientated fibres is produced, and which is flexible, the whole of the bundle may be fixed with a hardener if so desired.