Confocal optical imaging system with improved signal-to-noise ratio
Patent 4634880 Issued on January 6, 1987. Estimated Expiration Date: 
February 19, 2006. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
February 19, 2006. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3919698 Optical device for projecting a radiation beam onto a data carrier Patent #: 4139263 InventorsAssigneeApplicationNo. 06/830964 filed on 02/19/1986US Classes:250/566, Including coded record359/499Using compensation techniquesExaminersPrimary: LaRoche, Eugene R.Assistant: Pascal, Robert Attorney, Agent or FirmInternational ClassesG01N 21/21 (20060101)G02B 21/00 (20060101) G02B 27/10 (20060101) AbstractA confocal optical imaging system includes a laser for producing a linearly polarized beam which is transmitted through the optical elements of the system, focused on a small spot on the target, and reflected back through the optical elements to a photodetector where the reflectance from the spot is determined. The optical elements include a pinhole plate for restricting the size of the transmitted and reflected beams which plate, along with other of the optical elements, can produce unwanted reflections adding optical noise to the reflected beam from the target. A retardation plate between the pinhole plate and the target alters the polarization of the transmitted beam relative to the reflected beam so that a polarizer will discriminate between the true reflected beam signal and the unwanted reflections to thereby improve the signal-to-noise ratio at the photodetector.Field of SearchIncluding coded record | |
