Abstract:
A scanning reflection profilometry system utilizes an objective lens which focuses a beam at the surface under test and measures the profile of the surface (its height variations) in accordance with the amount of defocus of the reflected beam. Surface profile distortion which is focus dependent is reduced through the use of a transparent mask over the aperture of the lens in the path of the beam which is incident on and reflected from the surface under test and which covers a portion but not all of the aperture. A photodetector upon which the reflected beam is incident provides output signals representing the change in profile. The system has height sensitivity characteristic of a small spot size on the surface without signal distortion attributable to the diffraction anomalies associated with small spot sizes. A microprofilometer head having the objective lens and other optics is mounted on flexures and driven to execute reciprocal movement so as to scan the surface under test.
Abstract:
In order to facilitate pathological examination of a lesion in in-vivo tissue, a system and method are provided having a computer system in which both a camera for producing a digital macroscopic picture of the lesion and an imager are coupled to the computer system. The imager is responsive to the computer system and has optics for scanning the lesion to generate images representing microscopic sections of the lesion which provide sufficient information for pathological examination of the lesion. The computer system generates location information, referencing the location in the macroscopic picture of the lesion where the lesion was scanned to the images, and stores data in an electronic file structure which contains at least a representation of the images, a representation of the macroscopic picture, and the location information. The file structure may then be sent to another computer system for viewing the images stored in the file structure to facilitate pathological examination of the lesion by persons trained to interpret such images, adding a diagnostic report about the lesion to the data of the file structure, and sending back the file structure to the computer system that originated it.
Abstract:
A handheld confocal imaging system for in vivo observation of dermal and subdermal tissue allows diagnosis of conditions substantially beneath the surface of the skin. A confocal head has optics which scan the tissue so as to provide images of vertical sections of the tissue. Both two and three dimensional imaging may be provided for diagnosis and location of basal cell carcinomas and melanomas, and so as to enable visualization of tumor borders prior to excision.
Abstract:
A miniature scan engine for scanning a beam of monochromatic (laser) light across a bar code and receiving return light at a detector that provides electrical signals representing the code, utilizes an integral assembly of a laser (laser diode), the detector and a light collector mounted on flexures and rotated so as to scan the beam and receive the return light from the code. The collector is a body of material transmissive at the laser wavelength. The body presents an orientable surface so that the return light is incident at or close to perpendicular to the surface. In the body, parallel to the surface, is a volume hologram grating having Bragg planes arranged in rings around a center region in alignment with the detector. The angles of the Bragg planes vary progressively and decreases in a direction toward the center region so that light incident on the collector at angles of incidence, which vary from perpendicular to the surface by about + or -5.degree., are diffracted and propagate by guided mode propagation, including reflections at the internal surfaces of the body and transmission through the grating (because the light propagating along the paths intersects the grating Bragg planes off Bragg that is at an angle other than the Bragg angle) to the detector. Efficient collection of the light returned from the bar code symbol is obtained. The entire scan engine may occupy a volume of less than 1.25 cubic inch, thereby enabling bar code scanning and reading facilities in devices such as hand-held data collection terminals where space is at a premium.
Abstract:
A robust spectrophotometer (also known as a color spectrometer or colorimeter) is self contained in a housing which is adapted to be held-held and has all of the electrical, optical and electro optic elements mounted on a board captured within the housing at one end of which light from a sample is restricted to an object area and projected after being dispersed spectrally, as with a reflection grating, to an image area at a photodetector via a lens which has an optical axis and converges the dispersed light at the image area. The dispersive element is mounted on an arm having a pivot laterally offset from the dispersive element's surface where a diverging beam of light from the object area is incident and is deflected to the image area. The geometry is such that the dispersive element may be rotated to a position where the beam is specularly deflected (zeroth order diffraction), and the spectrometer calibrated when the dispersive element is in the specular reflection/deflection position. The path from the object area is approximately perpendicular to the optical axis, and then is folded by mirrors to direct the beam to incidence on the dispersive element, from which the beam is deflected and focused by the lens, the focal length of which is such that the image and object areas are in conjugate relationship. Radiant or electroluminescent sources, for example, the screen of a CRT monitor, can directly illuminate the object area. A pivotal foot on the housing having an aperture may be used to facilitate alignment of the sample with the entrance opening to the housing of the spectrophotometer.
Abstract:
Nonlinear optical cavities comprising a single or multiple ring paths for use with diode lasers are presented. In one embodiment, the total internal reflection surface of a monolithic or composite cavity is fabricated into a plurality of nonparallel planes. In another embodiment, a composite cavity with either a single end piece or a plurality of end pieces bound to a nonlinear resonator crystal is used to generate either a single or multiple ring paths. In several of the embodiments, incident laser beams entering one end of the cavity follow the ring paths and transmit from the other end of the cavity as a plurality of second-harmonic beams with a pre-defined spatial layout.
Abstract:
An improved apparatus and method for detecting the polarization state of an optical wavefront is disclosed, which is especially suitable for use in an integrated magneto-optic recording head. An optically transparent waveguide structure transmits TE and TM modes of the wavefront propagated as a beam coupled into the waveguide by a TE/TM grating coupler. In the waveguide structure is a periodic structure comprising a birefringent mode separator that splits the propagating beam into TE and TM modes. The mode separator comprises an array of uniformly spaced volumes of identical configuration. Photosensitive devices detect the intensity of the light contained within each of the separated beams. The signals from these photosensitive devices are used to determine the state of polarization of the optical wavefront. The periodic structure may, if desired, comprise regions of alternating birefringence, such as a Bragg grating, either in a waveguide layer or a cladding layer. Focal power is introduced (1) by providing focal power in the input grating coupler to the waveguide with a curved grating structure, (2) by varying the pitch of the birefringent mode separator extending in a direction transverse to the optical axis of the propagating beam, or (3) by introducing a surface grating with a varying pitch in a direction transverse of the optical axis.
Abstract:
An improved system for confocal imaging within dermal tissue of a patient is provided which minimizes instability in confocal images by reducing the relative motion of the tissue with respect to the confocal imaging optics of the system. The system includes a mechanism for maintaining an area of skin tissue under stress by application of force at the edges of the area, and an imaging head coupled to this mechanism for imaging the stressed skin. The mechanism includes a mechanical structure, such as a platen, brace, or attachment, which both supports the imaging head of the system and applies stress to a limited surface area of the tissue to minimize skin motion during confocal imaging.
Abstract:
A system for macroscopic and confocal imaging of tissue having a macroscopic imager for capturing a macroscopic image of the tissue's surface, a confocal imager for capturing one or more optically formed sectional microscopic images on or within tissue, a computer for receiving images from such imagers, and a tissue attachment device in which the macroscopic imager and confocal imager are each individually presented to the tissue utilizing the tissue attachment device in a predefined alignment, such that imaging locations of the confocal imager with respect to the tissue surface spatially correlate with macroscopic image. A user interface is operable on the computer to enable display of the macroscopic image on a display coupled to the computer, and to indicate a region within the macroscopic image associated with the field of view of the tissue imagable by the confocal imager. The user interface enables graphical tracking and targeting of imaging locations of the confocal imager in macroscopic image, and marking on the macroscopic image of the locations of confocal images with respect to the tissue surface.
Abstract:
An improved system for confocal imaging within dermal tissue of a patient is provided which minimizes instability in confocal images by reducing the relative motion of the tissue with respect to the confocal imaging optics of the system. The system includes a mechanism for maintaining an area of skin tissue under stress by application of force at the edges of the area, and an imaging head coupled to this mechanism for imaging the stressed skin. The mechanism includes a mechanical structure, such as a platen, brace, or attachment, which both supports the imaging head of the system and applies stress to a limited surface area of the tissue to minimize skin motion during confocal imaging.