Environmental Research Institute of Michigan

Siemens Vdo Automotive Corporation

Veridian Erim International, Inc.

Lauren M Peterson

Charles R Cook, Jr

Dan Reich

Alanna Marie Quail

Hubert Braunwarth

Dan O'Rourke

Mark Clark

Paul Witt

Jeff Clark

A vehicle occupant sensing system includes a laser array that generates three beams. A first beam is directed toward an upper body zone, a second beam is directed toward a middle body zone, and a third beam is directed toward a lower body zone. A first sensor assembly receives reflection beams from the upper body zone and generates a first signal that represents a proportional amount of an occupant present in the upper body zone. A second sensor assembly receives reflection beams from the middle body zone and generates a second signal that represents a proportional amount of the occupant present in the middle body zone. A third sensor assembly receives reflection beams from the lower body zone and generates a third signal that represents a proportional amount of the occupant present in the lower body zone. The laser array and the first, second, and third sensor assemblies are all mounted within a common housing that is mounted to a vehicle structure such as an A-pillar or rear view mirror. A central processor receives the first, second, and third signals and combines the signals to generate a control signal representative of the position of the occupant within the vehicle. The control signal is used to control deployment of an airbag based on the position of the occupant within the vehicle.

Vehicle occupant sensing system

A hand-held instrument provides a simple and elegant approach to determining the presence or absence of a surface condition such as roughening. A light source such as a laser diode illuminates a localized area of the surface to be characterized, and a light-sensitive detector is supported to receive light reflected by the surface and generate an electrical signal representative of the light received. An optical blocking element is placed at a first point along the axis of the reflected light, and a focussing lens is placed at a second point along the axis. If the surface is smooth or not sufficiently roughened, light is reflected substantially along the axis and blocked by the element so it does not reach the detector. If the surface is roughened, however, the reflected light is scattered off-axis and focussed by the lens onto the detector, thereby effectively bypassing the blocking element. Electrical circuitry is connected to receive the output of the detector and activate an indicator to which an operator may refer.

Surface characterization apparatus

An optical gauge for measuring the dimension of a hole in a workpiece employs an interferometric technique using a partially coherent radiation source. A beam of the radiation is directed to a beam splitter positioned a known distance from one of the known surfaces to produce a first sub-beam extending to a mirror and a second sub-beam along the axis of measurement. The mirror is adjustably positioned along the first sub-beam axis by a micrometer head. A radiation detector positioned on the opposite side of the beam splitter from the mirror receives light reflected by the second workpiece surface and light reflected by the mirror. Interference between the numerous wavelengths in the two beams results in a mixture of constructive and destructive interference at all positions of the mirror except that position where the path lengths are exactly equal. When the mirror is adjusted to this position, all wavelengths which make up the beams interfere constructively and a high amplitude signal is generated by the detector. The light at the detector has a speckle pattern and each detector element is approximately the size of a speckle. Three such sensors may be combined in a single gauge suspended in a bore for measuring the distances at 120 degree angles from the gauge to the bore wall and the true diameter is computed from the three distances.

Optical, interferometric hole gauge

A system for detecting minute amounts of water contaminant in semi-conductor microelectronic integrated circuits (MIC) includes two lasers 11,12 producing electromagnetic radiation at two discrete wavelengths. Each laser beam being sent through a chopper 13 and 14 respectively and combined via mirror 16 and beam splitter 17 to form a single two part beam along optical axis 22. The beam passes through a reflective beam splitter 26, a quarter wave plate 28 and lens 29 to be directed to a MIC 31 that is mounted onto drive mechanisms 31 and 32. Diffuse reflections from the bottom of the MIC or specular reflections from metallization layers pass back through MIC 31, lens 29, quarter wave plate 28, beam splitter 27 and through lens 48 to detector 47 which compares the intensity of the radiation at the two wavelengths with the intensities of the wavelengths as detected by detector 21 through a lock-in amplifier 49.

Contamination detection system

The present invention detects the difference in phase between the modulation of a received optical beam and a reference RF signal or a second modulated optical beam. The received optical beam is modulated by the reference signal and by this reference signal phase shifted 90 degrees. The difference cross modulation in these two modulated optical beams is detected. The phase difference to be detected is formed by dividing the difference cross modulation of the modulated second optical beam by the difference cross modulation of the modulated first optical beam. This quotient is proportional to the tangent of the phase difference to be detected. The optical modulation can be achieved by bulk electro-optic modulators operating on split beams, by a bulk electro-optic modulator alternatively modulating a single beam by the reference signal and the phase shifted version of the reference signal, or by changing the coupling between two parallel, matched wave guides in an integrated optic device. This system is useful in elimination of amplitude-phase cross talk in phase shift modulation optical communications systems and in three dimensional optical ranging systems.

Method and apparatus for electro-optical phase detection

A waveguide created by thermo-optically induced changes in the refractive index of a medium resultant from absorption of light focused thereupon. The medium absorbs optical energy of a preselected wavelength to cause a refractive index change in response thereto. A pulsed optical switch beam of the preselected wavelength is focused on the medium. The switch beam has an energy level adapted to create an optically induced focal region waveguide therethrough. An optical probe beam is focused on the medium and angularly offset with respect to the pulsed beam. The probe beam is optically confined within the waveguide to emerge from the medium as a diverging, cone-shaped beam.

Thermo-optically induced waveguide

A method and device for amplitude modulating a high powered beam of infrared radiation at frequencies in the megahertz range are disclosed. A laser is used to generate a beam of 4-40 watts of power and the beam is passed through as acousto-optical crystal having an acoustic transducer on one surface. A standing acoustical wave in the crystal is provided by a low powered drive signal at a frequency of one to ten megahertz. The beam is efficiently modulated by the standing wave at exactly twice the frequency of the drive signal. The device incorporates a heat sinking arrangement which serves to preclude deleterious action of divergent acoustical waves generated in the crystal, as well as to provide excellent removal of thermal energy.

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Ann Arbor, MI, United States of America

Lauren M Peterson