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US 4,792,931 AGranted
Optical seismic detector
AssigneeSchlumberger Technology Corporation
InventorsKatsuhiko Nishida, Mansanari Shindo, Masaharu Suzuki, Masamichi Kondo
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Abstract
A detector for detecting the acceleration, the velocity or the displacement of a point is described. The detector includes a light source, at least two photoelectric elements spaced apart from each other over a predetermined distance and a focusing optical system disposed between the light source and the photoelectric elements; the combination being particularly suited for use as an optical seismic detector for detecting and mapping an underground stratum structure.
Claims4
A servo accelerometer comprising:
- support member;
- a permanent magnet provided in fixed position on said support member;
- a coil positioned such as to be capable of producing a magnetic field which can magnetically interact with said permanent magnet;
- moveable supporting means including a vertical supporting rod and a horizontal supporting rod carried by said support member for supporting said coil moveably with respect to said permanent magnet;
- a light source provided in fixed position on said support member for emitting a light beam;
- light-receiving means provided in a fixed position on said support member for receiving said light beam from said light source, said light-receiving means being spaced apart from said light source;
- means coupled to said light-receiving means for producing a signal indicative of the position of impingement of said light beam on said light-receiving means;
- an optical system fixedly mounted on said movable supporting means intermediate said light source and said light-receiving means for magnifying the effect of lens displacement on said light-receiving means, said optical system comprising a quater pitch gradient index rod lens, said lens being affixed to said vertical supporting rod;
- and
- a servo amplifier for applying a driving current to said coil in response to said signal produced from said signal producing means.
7 more elements
Dependencies are inferred from the claim text.