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US 6,134,010 AGranted
Imaging system using polarization effects to enhance image quality
AssigneeLucid, Inc.
InventorJames M. Zavislan
Life of this patent
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AssigneeLucid, Inc.
InventorJames M. Zavislan
Estimating the term…
The quality of images produced by confocal microscopy, and especially scanning laser confocal microscopy, is enhanced especially for images obtained in turbid mediums such as many biological tissue specimens, by reducing speckle from scatterers that exist outside (above and below) the section which is being imaged by utilizing sheared beams, both of which are focused to laterally or vertically offset spots and polarizing the beams to have opposite senses of circular polarization (right and left handed circular polarization). The return light from the section of certain polarization is detected after passing through the confocal aperture of the confocal microscope. Images can be formed using optical coherence detection of the return light. Light from scatterers outside the section of interest, which are illuminated by both of the sheared beams, interfere thereby reducing speckle due to such scatterers, and particularly scatters which are adjacent to the section being imaged. Sheared beams having orthogonal linear polarization, as may be obtained from a Wollaston or Nomarski prism are converted into circularly polarized beams of opposite polarization sense by a quarter wave plate and focused into laterally displaced spot. A Dyson type lens is used to obtain sheared beams which when focused form vertically displaced spots. The optical signals representing reflections from the section are derived by polarizing optics which may either be a polarizing beamsplitter in the incident beam path or a retarder and analyzer. The retarder may be selected to provide different polarization phase shifts of the return light, and with the analyzer, detects the degree of elliptical polarization representing the optical activity and circular dichroism producing the optical signal representing the image.
A system for viewing of a section of a medium which receives and returns light both from the section and from sites adjacent to the section that reduces the quality of an image formed from said return light from said section, said system comprising a polarization separator and the polarization retarder, which are disposed successively in the path of the light received by the medium for processing the light said medium receives into light which is polarized generally orthogonally and is incident on said medium at spots spaced from each other, thereby providing interference of light returned from said sites and enabling construction of said image in response to a polarization parameter of said return light.
Scanning confocal microscope which comprises a laser providing an incident beam, a beam splitter, a scanner for scanning an image plane in a specimen section and generally orthogonal X-Y direction in said plane, a polarization separator which shears said beam into two beams along a direction along said incident beam, a polarization retarder providing said shear beams of generally orthogonal polarizations, and an objective for focusing said sheared beams at spots spaced in said direction in the vicinity of said image plane and which beams overlap outside the vicinity of said image plane and which beams overlap outside the vicinity of said image plane, a confocal aperture, a photo detector behind said aperture, and optics for focusing return light deflected by said beam splitter at said aperture.
An optical coherence imaging system which comprises a source providing light which is of low coherence, a beam splitter which deflects the light from said source into a reference arm and a sample arm to an image plane in a specimen section, a scanner in said sample arm for scanning said specimen in a generally orthogonal X-Y directions in said plane,, a polarization separator which shears said light into two beams, a polarization retarder providing said sheared beams each with an optical sense of generally orthogonal polarization, an objective having an optical axis for focusing said two beams at spots offset from each other in a direction generally along said axis which beams overlap outside the vicinity of said image plane, a detection arm into which light is directed by said beam splitter from said reference and sample arms, and means for providing images in response to interference of light in said detection arm.
Dependencies are inferred from the claim text.