Disc phonograph record playback by laser generated diffraction pattern
OwnerWilliam K. Heineinventor
Life of this patent
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Abstract
A laser beam is directed at the groove of a conventional disc phonograph record as it rotates, creating a reflected interference/diffraction pattern of the groove walls. The magnitude and rate of displacement of the interference/diffraction pattern is sensed and converted into an audio reproduction signal of the original phonograph recording.
Claims14
Apparatus for the playback of conventional disc phonograph records comprising a spiral recording groove having intersecting groove walls engraved in the disc surface and where flat land separates adjacent portions of the spiral groove, comprising:
- a. a laser for providing a laser beam of light;
- b. means for rotating a disc phonograph record to be played at the required rotational velocity;
- c. means for directing said laser beam to illuminate the record groove to create an interference-diffraction pattern comprising an arc of light of variable radius which is radially displaced along a vector, above and below a middle unmodulated position, and whose maximum-to-minimum radial displacement relative to its unmodulated position is proportional to the actual groove wall displacement relative to its unmodulated position and represents the amplitude of the recorded signal, and wherein the rate of change of the radial displacement of the arc of light corresponds to the frequency of the recorded signal;
- d. tracking means for maintaining said laser beam directed within the record groove as the disc phonograph record rotates;
- e. means positioned to intercept the interference-diffraction pattern for detecting the displacements of the interference-diffraction pattern created by the reflected laser beam;
- and
- f. means responsive to said detecting means for converting said displacement variations of the interference-diffraction pattern into an electrical sound reproduction of the recording.
Sound reproduction apparatus for the playback of conventional disc phonograph records having grooves containing sound signal information recorded therein comprising:
- means for directing a laser beam along and within the grooves of a rotating disc phonograph record to create a dynamic interference-diffraction light pattern comprising an arc of light of variable radius which is radially displaced along a vector, above and below a middle unmodulated position, and whose maximum-to-minimum radial displacement relative to its unmodulated position is proportional to the actual groove wall displacement relative to its unmodulated position and represents the amplitude of the recorded signal, and wherein the rate of change of the radial displacement of the arc of light corresponds to the frequency of the recorded signal;
- and
- means for detecting said radial displacements of said dynamic interference-diffraction light pattern and converting the same to an electrical sound signal reproduction of the original disc phonograph recording.
Apparatus for the playback of conventional disc phonograph records comprising a spiral recording groove having intersecting groove walls engraved in the disc surface and where flat land separates adjacent portions of the spiral groove, comprising:
- (a) a laser for providing a laser beam of light;
- (b) means for rotating a disc phonograph record to be played at the required rotational velocity;
- (c) means for directing said laser beam to illuminate the record groove to create an interference-diffraction pattern comprising an arc of light defined by the groove wall which is positionally related to a vector, above and below a middle unmodulated position, and whose maximum-to-minimum positional variation relative to its unmodulated position is proportional to the actual groove wall displacement relative to its unmodulated position and represents the amplitude of the recorded signal, and wherein the rate of change of the positional variation of the arc of light corresponds to the frequency of the recorded signal;
- (d) tracking means for maintaining said laser beam directed within the record groove as the disc phonograph record rotates;
- (e) means positioned to intercept the interference-diffraction pattern for detecting the positional variations in the interference-diffraction pattern created by the reflected laser beam;
- and,
- (f) means responsive to said detecting means for converting said positional variations of the interference-diffraction pattern into an electrical
- sound reproduction of the recording.
Sound reproduction apparatus for the playback of conventional disc phonograph records having grooves containing sound signal information recorded therein comprising:
- means for directing a laser beam along and within the grooves of a rotating disc phonograph record to create a dynamic interference-diffraction light pattern comprising an arc of light defined by the groove wall which is positionally related to a vector, above and below a middle unmodulated position, and whose maximum-to-minimum positional variations relative to its unmodulated position is proportional to the actual groove wall displacement relative to its unmodulated position and represents the amplitude of the recorded signal, and wherein the rate of change of the positional variations of the arc of light corresponds to the frequency of the recorded signal;
- and
- means for detecting positional variations of said dynamic interference-diffraction pattern and converting same to an electrical sound signal reproduction of the original disc phonograph recording.
Dependencies are inferred from the claim text.