Optical f i l t e r s Patent 1 206 260 granted to A. P. P r e d r i c k . (Oct. 23, 1969) A wavelength selective light s c r e e n permitting the passage of blue-violet light, but not red light, c o m p r i s e s a thin p e r f o r a t e d sheet sandwiched between strengthening sheets. B e a m splitter
Patent 1 206 461 granted to E l e c t r i c and Musical Industries Ltd. (Jan. 8, 1968) A coil of wire is placed between two p r i s m s of a beam splitter. Cement is introduced between the p r i s m s , but is prevented by the wire f r o m clouding the optical path. Light guides Patent 1208 472 granted to Rank Organisation Ltd. (Feb. 28, 1969) A light guide is f o r m e d by winding a light transmitting filament onto a f o r m e r so that the filament is laid repeatedly over the same endless loop which has at least one c r o s s i n g point. The bundle is cut to give a light guide. Optical cables Patent 1 211 005 granted to Joseph Lucas (Industries) Ltd. (Feb, 9, 1968) An optical cable in a protected shroud is used in a vehicle lighting system. An e l e c t r i c a l conductor extends along the length of the cable. Light modulator Patent 1 211 565 granted to Compagnie Generale d ' E l e c t r i c i t e (Feb, 19, 1968) A monochromatic light beam is amplitude o r phase modulated by passing it through a s e m i - c o n d u c t o r or s e m i - m e t a l l i c crystal. The absorption c h a r a c t e r istic of the c r y s t a l may be v a r i e d by causing the free c a r r i e r s in the c r y s t a l to p e r f o r m absorbent t r a n s i tions between the Landau levels. In the absence of a magnetic field, the c r y s t a l is t r a n s p a r e n t to light.
STORAGE AND R E C O R D I N G Fourier transform recording Patent 1202 552 granted to British A i r c r a f t Corp Ltd. (Aug. 2, 1968) To r e c o r d the F o u r i e r t r a n s f o r m of an object, an image of the object in incoherent light is f i r s t focused at a focal plane. This causes a deformable surface, spaced f r o m the focal plane, to be locally distorted according to the local intensity of light in the image. The surface is illuminated with coherent light which is collected on reflection enabling the F o u r i e r t r a n s form of the object to be r e c o r d e d . Irradiation marking Patent 1 201 543 granted to J . M . Gilchrist. (March 12, 1968) The inner wrap of a packaged article (eg. cigarettes) can be m a r k e d by treating this wrap with a light responsive m a t e r i a l and irradiating the package through a patterned plate or stencil. Holographic recording Patent 1 204 873 granted to Agfa-Gevaert A. G. (Sept. 19, 1967) Holographic images of pictures for recording or r e production a r e r e c o r d e d on a rotatable disc or tape.
No appreciable change of viewpoint is seen when this is moved continuously past a l a s e r beam and scanning device for reproduction of the moving pictures. Hologram reconstruction Patent 1 205 224 granted to Philips Electronic & Associated Industries Ltd. (Dec. 4, 1967) A hologram is r e c o n s t r u c t e d using a polychromatic source, and a device to r e v e r s e the dispersion p r o duced by the hologram. A substantially a c h r o m a t i z e d image is produced. Hologram formation Patent 1 208 586 granted to Texas I n s t r u m e n t s Inc. (Dec. 12, 1967) An information c a r r y i n g beam from the object is split and the partial beams recombined at the r e c o r d ing medium. Hologram reproduction Patent 1 210 486 granted to A g f a - G a e v e r t A . G . (April 14, 1969) To reproduce holograms of low-spatial frequency, a f o c u s e d - i m a g e hologram with an off-axis reference beam is used as the original. I N S T R U M E N T S A N D COMPONENTS
Photographic m a t e r i a l Patent 1 201 396 granted to Eastman Kodak Co. (Jan 3, 1968) Photographic m a t e r i a l s , p a r t i c u l a r l y silver halide emulsions and vacuum deposited silver halide l a y e r s a r e sensitised by a noble metal s e n s i t i s e r and a labile Se compound f o r m e d by activating a nonlabile Se compound. Electro-photographic p r o c e s s Patent 1201 497 granted to Rank Xerox Ltd. (Sept. 28, 1967) The pins in a pin m a t r i x a r e connected to a common point through a common field-effect s e m i - c o n d u c t o r layer. An image-configurated electric field is applied so that the conductivity of the layer and the impedance to the point of the pins v a r i e s accordingly. Photoelectric s p e c t r o m e t e r Patent 1201 504 granted to the C o m m i s s a r i a t a l ' e n e r g i e Atomique. (Nov. 23, 1967) In a device for photoelectrically scanning a spectrum, the d i s p e r s e d beam is reflected by a rotating m i r r o r on to a s e r i e s of fixed m i r r o r s . It is then reflected through a number of slits to a small number of detectors. The device could be used for analysing t r a n s i tory chemical species in rapid reactions by infrared spectrography. Diffraction gratings Patent 1 206 035 granted to D. Rudolph & G. Schmahl. (Feb. 9, 1968) A p h o t o - r e s i s t layer is placed in an interference pattern and after development used directly as a reflection o r t r a n s m i s s i o n grating or as a mask in forming such a grating. Interference f i l t e r s Patent 1206 401 granted to Pavelle Ltd. (Dec. 1, 1967) An interference filter c o m p r i s e s a base-plate on which an interference film has been deposited. This gives coated a r e a s surrounded by uncoated a r e a s and vice versa. The coated a r e a s reflect undesired wavelengths.
optics and L a s e r Technology