Abstract: The object of the invention is a method and an apparatus for optical measurement of a surface profile of a specimen, a series of n images of the specimen being acquired with an image acquisition apparatus in different planes in the z direction of a coordinate system (x, y, z). The image contents of all n images of the resulting image stack are compared to each other in the z direction at each coordinate point (x, y) in order to determine a plane therefrom according to predetermined criteria, assign its plane number (N) to that coordinate point (x, y), and store it in a mask image. The mask image contains all the 3D data of the specimen surface. Processing can be performed using 2D image processing procedures. The 3D information can be quickly and easily retrieved from the mask image. The surface profile can be reconstructed and displayed three-dimensionally.

Abstract: The invention features a fly height measurement system for measuring fly height of a slider over a storage disc. The fly height measuring system includes a source of light, a slider, a detector module and a processor. The source of light produces light along a light path. The slider includes an objective lens positioned such that light from said source hits the objective lens and is directed toward a surface of a disc. Light propagating from the disc is directed to a detector. The processor estimates the fly height of the slider based on detector module output.

Abstract: A measurement system is provided that is capable of analyzing light at the input of an optical waveguide of an optical device under test (DUT) and/or at the output of the waveguide, preferably at both. At the input of the waveguide, light having a particular polarization state generated by a polarization controller is output from the polarization controller and coupled into a proximal end of an optical fiber. The measurement system analyzes the polarization state of the light being launched from the opposite, or distal, end of the optical fiber into the waveguide input of the DUT to determine whether and by how much the polarization state of the light has been changed by the optical fiber. The polarization controller is altered, if necessary, to compensate for any changes in the polarization state caused by the optical fiber so that the polarization state of light being launched into the input of the optical fiber is known and is controllable.

Abstract: An active (laser-illuminated) imaging system is described that is suitable for use in backscatter absorption gas imaging (BAGI). A BAGI imager operates by imaging a scene as it is illuminated with radiation that is absorbed by the gas to be detected. Gases become “visible” in the image when they attenuate the illumination creating a shadow in the image. This disclosure describes a BAGI imager that operates in a linescanned manner using a high repetition rate pulsed laser as its illumination source. The format of this system allows differential imaging, in which the scene is illuminated with light at least 2 wavelengths—one or more absorbed by the gas and one or more not absorbed. The system is designed to accomplish imaging in a manner that is insensitive to motion of the camera, so that it can be held in the hand of an operator or operated from a moving vehicle.

Abstract: Disclosed are mechanisms for selectively filtering spatial portions of light emanating from a sample under inspection within an optical system. In one embodiment, a programmable spatial filter (PSF) is constructed from materials that are compatible with light in a portion of the UV wavelength range. In a specific implementation, the PSF is constructed from a UV compatible material, such as a polymer stabilized liquid crystal material. In a further aspect, the PSF also includes a pair of plates that are formed from a UV grade glass. The PSF may also include a relatively thin first and second ITO layer that results in a sheet resistance between about 100 and about 300 &OHgr; per square. The PSF provides selective filtering in two directions. In other words, the PSF provides two dimensional filtering.

Abstract: A method and apparatus for protecting workers from casualty due to a combustible gas. A portable combustible gas detector is disclosed which is particularly suitable for portable use. The detector generally comprises a circuit, housed in the same chamber as the sensor, for controlling the operation of the gas detector; and operation software for operating the detector through the circuit. The circuit of the detector is encased in armor to protect the circuit from electromagnetic wave disturbance. The detector is particularly suitable for measurement of a combustible gas with a low concentration. Advantageously, the present invention enables a worker to conveniently carry a small and lightweight combustible gas detector into a hazardous worksite to improve the safety of each worker carrying the device.

Abstract: Disclosed are mechanisms for selectively filtering spatial portions of light emanating from a sample under inspection within an optical system. In one embodiment, a programmable spatial filter (PSF) is constructed from materials that are compatible with light in a portion of the UV wavelength range. In a specific implementation, the PSF is constructed from a UV compatible material, such as a polymer stabilized liquid crystal material. In a further aspect, the PSF also includes a pair of plates that are formed from a UV grade glass. The PSF may also include a relatively thin first and second ITO layer that results in a sheet resistance between about 100 and about 300 &OHgr; per square.

Abstract: A method and apparatus for detecting properties of reflective transparent surface coatings on a sheet of transparent material, such as a sheet of glass or a sheet of plastic material. One or more light beams are directed at an angle to the surfaces of the material under test and the energy in surface reflections is sensed. The presence and surface location of a surface coating is determined from the relative magnitudes of surface reflections of the light beam. The type of coating is determined from the magnitudes of reflections from the surface coating of one or more different wavelength light beams. The surface coating may be, for example, a Low-E coating, or a metal or metal oxide coating left on a sheet of float glass.

Abstract: A defect inspection apparatus for detecting defects existing on a surface of a semiconductor sample and/or inside the sample based on light information from the sample obtained by irradiating a light beam onto the sample is provided, which comprises a detecting means for detecting positions in the depth direction where the defects exist and distribution of the defects based on the light information; a setting means for setting a position in the depth direction where defects exist; and a means for displaying the distribution of the defects obtained by the detecting means, the displaying means displaying the distribution of the defects corresponding to the position in the depth direction set by the setting means.

Abstract: There is described method and apparatus to create multi-dimensional non-spatial histograms of surfaces and to compare such histograms to show whether the surfaces substantially conform to one another. This analysis is particularly applicable to comparing die on wafers to determine whether manufactured devices conform to a master or whether one die is like another.

Abstract: An on-line sensor is provided that supplies light to a spectrophotometer to measure the color a product extruded through a conduit having a bypass section. The on-line sensor includes a transparent member with an opaque outer surface and an interior portion extending from a first end to a second end to the transparent member. The interior portion is connected to the bypass section, and the product that flows through the bypass section is supplied to the interior section of the transparent member. A light source connected to the transparent member and provides light to the transparent member inside the opaque outer surface. A light receiver is connected to the transparent member and captures light from the light source in the transparent member that is affected by the product. The captured light is supplied to the spectrophotometer to at least measure the properties of the product supplied to the interior portion of the transparent member.

Abstract: The ability to inspect photomasks for errors or defects in phase-shifters is greatly enhanced using optical techniques based on multiple modified radiation collection techniques. In particular, the apparatus and methods of the invention allows for errors in phase-shifters to be more accurately detected, even in the presence of regular amplitude objects such as grid lines. In one embodiment, the intensities of two slightly defocused images of phase objects corresponding to the same photomask location are compared. In a second embodiment, radiation having two Zernike point spread functions is used to obtain two slightly different phase sensitive images. Data collected and analyzed using this method provides much greater sensitivity to phase objects and errors in phase objects than prior art inspection systems. Embodiments include both scanning-type and projector-type optical architectures and may utilize radiation transmitted or reflected by a sample.

Abstract: The present invention is directed to a method and apparatus for testing a fiber-optic cable. An Optical Time Domain Reflectometer (OTDR) is presented. Test signals are generated from the OTDR and received by the OTDR for processing. The received test signals are sampled and analyzed. The received test signals include reflectance spikes and a slope. A first-order derivative is taken of the received signal. The first-order derivative is then filtered to remove the reflectance spikes and the slope. Discontinuities in the filtered first-order derivative denote a fault in the fiber-optic cable.

Abstract: The present invention relates to a method of determining a thickness of at least one layer on at least one semiconductor wafer (12), comprising the steps of: projecting a first laser pulse (14) on a surface (16) of the at least one layer (10), thereby generating an acoustical wave due to heating of the surface of the at least one layer (10); after a propagation time of the acoustical wave, projecting a series of second laser pulses (18) on the surface (16) of the at least one layer (10); measuring reflected laser pulses (20) of the second laser pulses (18), thereby sensing the times of reflection property changes of the surface (16) of the at least one layer (10); and determining the thickness of the at least one layer (10) by analyzing the times of reflection property changes. The present invention further relates to a system for determining a thickness of a layer (10) on a semiconductor wafer (12).

Abstract: A method and apparatus for measuring a slurry distribution. A slurry solution is doped with a light absorbing dye having an absorptivity sensitive to a physical parameter such as acidity, temperature or pressure. The solution is delivered between a platen and substrate in a first physical state where it absorbs light. A laser beam is generated, transmitted through the slurry layer, reflected off of the substrate, and detected by a photodetector. The thickness of the slurry is measured from its absorptivity and the transmittance of the laser beam. A relative motion between the light source and substrate allows the slurry layer thickness to be measured as a function of distance from the center of the substrate. A final water rinse removes the slurry and brings any residual slurry to a/second physical state where it does not absorb light.

Abstract: A device for analyzing plasma enclosed in a chamber. The device has a lens array which has a plurality of lens array lenses. The lens array lenses are located in a position so that the line of sight for each lens array lens intersects one another at a single point in front of the lens array. Each lens array lens is also located in a position so that each lens array lens is focused near a rear wall of the chamber. Behind each lens array lens is a cable having a first end and a second end. The first end of the cable is located in a position to receive emission elements through the lens array lens. A collimating lens is located at the second end of the cable to couple the emission elements from the second end of the cable through a wavelength selective element. A recording device is located in a position to record the emission elements through the wavelength selective element.

Abstract: A liquid measuring cell for measuring optical properties of liquids, with a measuring chamber (16), which is adjoined on one side by a transparent window (11), and with a reflector (30) disposed on the opposite side of the measuring chamber (16), which reflects the light striking it toward the outside through the measuring chamber (16) and the window (11), is particularly easy to clean and permits favorably reproducible measurements if another transparent window (33) is disposed between the reflector (30) and the measuring chamber (16) and this window (33) adjoins the measuring chamber (16) on the other side.

Abstract: An instrument for analyzing and dispensing objects larger than about 70 &mgr;m in diameter is based on a flow cytometer with a novel fluidic switch arrangement for diverting a portion of a sample stream in response to detector signals in a flow cell. The instrument is particularly adapted for dispensing multicellular test organisms like nematodes or large microspheres for use in screening large libraries of potential pharmaceutical agents. Hydrodynamic focussing is used to center and align the objects in the flow cell. The objects pass through a sensing zone where optical or other characteristics of the objects are detected. The detector signals are processed and used to operate a fluidic switch that is located downstream from the sensing zone. The fluid stream containing the detected objects emerges from the flow cell into air where a fluid stream controlled by the fluidic switch diverts portions of the stream containing no sample objects or sample objects not meeting predetermined characteristics.

Abstract: A device (V) for optical inspection of open beverage cans (D) having a light source (Q, Q′) positioned outside the can, a reflector (R) for reflected light from the inside of the can, arranged between the light source and the opening in the can, a camera (E) which is alighed with the reflector, and an optical device (P) with which the light (11) from the light source (Q, Q′) can be projected from above through the opening (4) in the can directly onto the bottom (B) of the can, whereby the can collar (K) can be illuminated from the bottom (B) of the can on the inside. In this method, the light is bundled and directed through the narrow section of the reflector, then expanded after the reflector and projected directly onto the can bottom (B) centrally as the light spot (13, 13′) displacing the light source (Q, Q′) into the can in order to illuminate the inside wall of the collar from beneath from the light spot and to image it by the reflected light.

Abstract: The surface inspection apparatus according to the present invention obtains images of a test piece by capturing images of the test piece with an image-capturing device while varying at least one apparatus condition (e.g., the wafer tilt angle) through apparatus condition adjustment and determines an optimal setting at which a surface inspection is to be conducted on the test piece based upon the images thus obtained. As a result, the optimal setting for the inspection can be accurately ascertained with ease even when the pitch of a pattern formed at the surface of the test piece is not known, thereby making it possible to perform a surface inspection while sustaining high levels of accuracy and efficiency at all times.