Patent GB-883517-A (GB)
Title: Improvements in or relating to recording apparatus
IPC: G01D15/14
Filed: 1957-12-20
Abstract: 883,517. Recording-apparatus. MINNEAPOLIS - HONEYWELL REGULATOR CO. Dec. 20, 1957 [Dec. 28, 1956; Feb. 7, 1957 (2)], No. 37585/60. Divided out of 883,516. Class 106 (4). [Also in Group XX] Apparatus for recording on a film F sensitive to ultra-violet radiation the variations with time of an observed phenomenon, comprises a lamp 128 emitting a large proportion of ultraviolet radiation and an optical system, Figs. 14, 17, including a converging lens 134 close to the lamp 128 for collecting its rays in a beam, the system bringing the beam to a focus as it impinges on the film F and including a galvanometer mirror 136 deflecting the beam in accordance with variations in the observed phenomenon. The lamp. A high pressure, mercury-vapour lamp 128 having a point-shaped arc is used comprising a quartz envelope containing an inert gas and some mercury. The anode is tungsten and an ignition electrode projects from the side of the envelope. The brightness of the arc is about 100,000 stilb. per square centimetre and a high percentage of the radiation is ultraviolet. In order to compensate for expansion and stress due to the high temperature and pressure within the lamp, it is mounted on double-armed spring terminals and can be adjusted vertically by screw 107, accessible through a hole in the cover 3 when a plug 16 is removed. To prevent harmful radiation affecting the user, the lamp is enclosed in a housing preventing escape except in the desired direction through the lens 134, the screw 107 carries a baffle plate 108 and the access door 15 is shielded by a wall 200. The optical system. Rays falling on the segmental cylindrical lens 134 about half an inch from the lamp 128 are collected and directed as a diverging wedge-beam with parallel sides 143 to a cylindrical lens 135 with its axis just out of parallel with the galvanometer mirror 136 to prevent the formation of a " ghost " image. The lens 135 concentrates as much as possible of the radiant energy in the horizontal plane on to the mirror 136 which reflects it as a converging wedge-beam with parallel sides 145. The beam is reflected by a mirror 137 on to another segmental cylindrical lens 138 which focuses it on to a small spot of high intensity on the surface of the film F where it produces a latent image and can also be observed through a transparent part of the case against a transverse scale. The lenses 134, 135 and 138 may all be quartz coated with magnesium fluoride of thickness one-fourth wavelength at 3600 angstrom units to protect the surfaces and reduce reflection. The mirror 136 is optically flat, coated with aluminium and overcoated with magnesium fluoride of thickness of halfwavelength at 3600 angstroms to reinforce reflections. The lens 134 can be adjusted relative to the lamp 128 and secured by a screw 155. Galvanometers. The beam may be de-   flected independently by each of a plurality of galvanometers 158 supported on the base 2, Fig. 4, with a permanent magnet 159 having stationary polepieces 160 with which co-operate polepieces 161 of the galvanometer bodies 158. Each galvanometer body 158 has elongated hollow parts 162, Fig. 3, supporting a quartz filament carrying a mirror 136 and a coil located between the polepieces 161. Film supply, loading and driving. To load film into the recorder, the top 3 is lifted about hinge 4, to give access to a housing 79, 80, 82 closed by a guide plate 96 and cover 99. These are also lifted and a roll of film F mounted on a shaft 84 is placed with the ends of the shaft in slots 83 in the housing side walls and resting on the upper arms 85 of U-shaped springs. When the top 3 is closed the drive roller 76, which is lowered thereby engages the stock roll and compresses the springs 85. The shaft 84 moves down the slots 83 and a pointer 94 held by springs 89 in contact with the shaft 84 indicates against a scale that the supply roll is full. A spring 102 can now close the cover 99, the guide plate 96 is rotated downwardly until the spring 98 engages the wall 79 and the top 3 descends until a part thereof depresses the guide plate 96 into horizontal position beneath the outgoing film F, thus locating the drive roller 76 in relation to the film. The drive roller 76 is driven from a motor 21 by a belt and sprocket arrangement through a four-speed gear and clutch device. The motor 21 is of constant speed, shaded pole, rotating field type. Power supply and cooling. The power switch for a fan motor 174 is interlocked with switches for energizing the drive motor 21 and starter circuit of the lamp 128. The motor 174 drives a fan 190 drawing air through the recorder, the case having screened openings in its sides. The apparatus may be used to produce the latent image forming one step in the process described in Specification 883,516.