Abstract: An optical element includes a microlens array and a reflective surface. The microlens array has a focal curve and a focal length, and the reflective surface is spaced from the focal curve. When used as an exit-pupil expander, such an optical element can often generate output beamlets that have a more uniform brightness than the output beamlets generated by a diffractive optical element. Furthermore, such an optical element can define an output-beamlet envelope having an aperture that is less wavelength-dependent than the aperture of an output-beamlet envelope defined by an exit-pupil expander that incorporates a diffractive optical element. In addition, such an optical element can often produce an image having less speckle than an exit-pupil expander that incorporates a diffractive optical element when used with one or more coherent light sources.

Abstract: A scan assembly of an image generator sweeps an image beam in a first dimension at a first rate and bi-directionally in a second dimension at a slower rate. Sweeping the beam bi-directionally in the vertical dimension (generally the dimension of the lower sweep rate) can reduce the scanning power by eliminating the flyback period, and, where the scan assembly includes a mechanical reflector, can reduce the error in the beam position without a feedback loop by reducing the number of harmonics in the vertical sweep function. Furthermore, because the image beam is “on” longer due to the elimination of the flyback period, the scanned image is often brighter for a given beam intensity. The scan assembly may also sweep the image beam non-linearly in the vertical dimension, and this sweep may be bi-directional or uni-directional. Sweeping the beam non-linearly can also reduce the error in the beam position by reducing the number of harmonics in the vertical sweep function.

Abstract: A projection system, such as a system suitable for head-up displays in automobiles, includes a laser projection source (101) and a scanner (102). Light from the laser projection source (101) is scanned across a projection surface (104), which can be a car's windshield. The projection surface (104) includes a buried numerical aperture expander (105) capable of reflecting some light and transmitting other light. The system may also include an image projection source (551) capable of presenting high-resolution images on a sub-region (552) of the projection surface (604) that has a optical relay (650) disposed therein.

Abstract: Briefly, in accordance with one or more embodiments, a birefringent layer may be utilized in conjunction with a head-up display (HUD) for a vehicle or the like, for example where the birefringent layer is disposed in or on the windshield. The birefringent layer may impart a change in the polarization of light emerging from a projector of the head-up display in order to reduce or minimize interference between beams from the display and reflecting off of two or more surfaces that are combined at the viewer's eye, and/or to reduce or minimize the effect of polarizing sunglasses on the viewability of the image projected by the display. In one or more embodiments, the birefringent layer alters the polarization of the light reaching the viewer's eye if the user is wearing polarizing glasses or lenses so that less light from the display is blocked.

Abstract: An optical substrate guided relay (300) includes a light homogenizing device (321) coupled to an optical input device (301) in an offset orientation along a first interface (331). The light homogenizing device (321) receives light from an image-producing source (804), which can be a scanned beam source, and creates multiple copies of the received light by way of a light homogenizing device (321). The light and copies are delivered to the optical input device (301). An optical substrate (302) receives light from the optical input device (301) as the light spirals down the optical input device (301) due to the offset coupling with the light homogenizing device (321). An optical output device (303), coupled to the optical substrate (302) distally from the optical input device (301) delivers the light to a user (803) with one or more partially reflective surfaces (304).

Abstract: A scanned beam projection system includes a polarizing beam splitter, a polarization rotating component and a scanning mirror. Light is directed on a first light path to the polarizing beam splitter at a substantially constant angle of incidence. The P-polarized light passes through. The P-polarized light passes through the polarization rotating component, is reflected off the scanning mirror back through the polarization rotating component, and arrives at the polarizing beam splitter as S-polarized light with a non-constant angle of incidence. The S-polarized light is reflected by the polarizing beam splitter, and a scanned image results.

Abstract: A device for driving a plant such as a beam scanner includes a memory, drive-signal generator, and a calibrator. The memory stores data corresponding to the drive signal, and the generator generates the drive signal from the data and couples the drive signal to the plant. The calibrator measures a response of the plant to the drive signal, calculates a difference between the measured response and a corresponding target response, and reduces the difference by altering the drive signal. Such a device can force the output response of the driven plant to equal a target output response, or to be sufficiently close to the target response for a particular application, while the device is operating in an open-loop configuration. Furthermore, while operating in an open-loop configuration, such a device often has a greater stability margin and greater noise immunity than a comparable device that operates in a closed-loop configuration.

Abstract: Methods, apparatuses, and systems for identifying a digital fingerprint. One embodiment compensates for the inaccuracies resulting from the unstable nature of the circuits that yield digital fingerprints and, therefore, allows for reliable identification of these digital fingerprints. According to one embodiment, the digital fingerprint (identification) is divided into a plurality of sections and stored in a database. According to this embodiment, fingerprints are identified by comparing the sections of the fingerprint to be identified with corresponding sections of the fingerprints stored in the database. The matching fingerprint, in one embodiment, is the fingerprint associated with a statistically sufficient number of matching fingerprint sections. Other embodiments of the present invention optimize the section lookup methodology based on the stability of the sections of the fingerprint.

Abstract: A scanning beam assembly includes a beam generator to generate a beam of radiation; at least one reflector configured to deflect the beam across a field of view; and a plurality of multi-mode optical fibers for receiving radiation reflected from the field of view, wherein the optical fibers have end surfaces that face in at least two different directions, or wherein the optical fibers are configured to receive scattered radiation from an angular field of view larger than that determined by their individual numerical apertures.

Abstract: Briefly, in accordance with one or more embodiments, an input device may be utilized in conjunction with a scanned beam display or the like, or may be based on the scanning platform as used in a scanned beam display such as a MEMS based scanner. An input event such as illumination of a photodetector or reflection of a scanned beam off of a retroreflector may be correlated with a timing event of the scanning platform such as a refresh signal, or a horizontal and vertical sync signals. The correlation of the timing event may be representative of an X-Y location, and in some embodiments of a Z location, that may be utilized to provide input data back to a host device.

Abstract: Briefly, in accordance with one or more embodiments, time averaged Moiré patterns may be utilized in a scanned beam display having a Gaussian beam profile or the like in order to tailor uniformity of the image by controlling both the near field and far field regions of the display to result in a stable and uniform scanned beam display image. Consideration is made regarding the light source parameters of focus numerical aperture, profile, shape, and/or wavelength to achieve higher uniformity and stability without resulting in significant visible coherent artifacts such as tiled intensity patterns and/or Moiré.

Abstract: The radiance of a laser diode is a function of laser diode drive current. The radiance is also a function of other factors, such as age and temperature. A laser projection device includes laser diodes to generate light in response to a commanded radiance, and also includes photodetectors to provide a measured radiance. The commanded radiance and measured radiance are compared, and drive currents for the laser diodes are adjusted to provide luminance and color balance tracking.

Abstract: A method for detecting scanner phase error in a bidirectional scanned beam imager includes obtaining first and second images derived from respective first and second scan directions, comparing apparent image feature positions in the first and second images, and calculating a phase error corresponding to a difference between the apparent image feature positions. The comparison may include multiplying frequency domain transformations of the images.

Abstract: The luminance of a laser diode is a function of laser diode drive current. The luminance is also a function of other factors, such as age and temperature. A laser projection device includes laser diodes to generate light in response to a commanded luminance, and also includes photodiodes to provide a measured luminance. The commanded luminance and measured luminance are compared, and drive currents for the laser diodes are adjusted to compensate for changes in laser diode characteristics.

Abstract: Briefly, in accordance with one or more embodiments, an operational state of a MEMS device of a scanner system may be determined. In the event it is determined that the MEMS device is possibly operating in an unsafe mode, the laser may be turned off and/or the MEMS device may be shut down. An operational state of the MEMS device may be determined for example by obtaining a MEMS drive voltage sense signal and/or a MEMS drive current sense signal, and a potentially unsafe mode of operation may be identified if one or more of such signals are not at proper values with respect to predetermined threshold values.

Abstract: Embodiments relate to a MEMS device including a scanner rotatable about at least one rotation axis, with the scanner having a characteristic resonant frequency. According to one embodiment, the MEMS device includes drive electronics operable to generate a drive signal that causes the scanner to oscillate at an operational frequency about the at least one rotation axis. The drive signal has a drive frequency selected to be about equal to the characteristic resonant frequency or a sub-harmonic frequency of the characteristic resonant frequency. According to another embodiment, the drive electronics are operable to generate a drive signal having a plurality of drive-signal pulses that moves the scanner at an operational frequency and sensing electronics are operable to sense a position of the scanner only when the drive-signal pulses of the drive signal are not being transmitted by the drive electronics. The MEMS device embodiments may be incorporated in scanned beam imagers, endoscopes, and displays.

Abstract: An endoscope system and method includes an endoscope tip coupled to a endoscope console for providing images of anatomical features imaged using the endoscope system. The system also includes a calibration device having known optical properties. The calibration device is imaged using the endoscope system, and data corresponding to the image is obtained. This data are compared to data corresponding to the known optical properties of the calibration device. Based on this comparison, calibration data corresponding to imaging errors of the endoscope system are obtained. The calibration data are used to calibrate the endoscope system.

Abstract: Briefly, in accordance with one or more embodiments, a proximity detector is placed proximate to projector to detect an obstruction disposed proximate to the projector. The proximity detector is capable of estimating the distance from an object to the projector. If an object is detected within a minimum distance, the projector operation may be altered, for example to cause the projector to turn off, or to reduce the intensity of emitted light so that the power of the emitted light the minimum distance will be reduced to below a selected range. Furthermore, if an object cannot be detected within or near a maximum distance, the projector operation may likewise be altered, for example the proximity detector may cause the projector to turn off.

Abstract: A MEMS-based projector may be included in various user devices. A selective fold mirror, a MEMS-based projector, and a polarization rotator may be oriented to reflect a beam within the device for external projection. Alternatively, a total internal reflection prism may take the place of a selective fold mirror or a polarization rotator and may reduce the number of necessary components in the user device. Various optical components may be placed in the MEMS-based projector and arranged in different positions to reflect a light beam in a desired direction for external projection. The components that make up the MEMS-based projector may depend on the available footprint in the device and the direction in which the light beam is to be projected. Some optical components may provide multiple functionalities which would otherwise require multiple components and may reduce the size of the projector.

Abstract: A MEMS oscillator, such as a MEMS scanner, has an improved and simplified drive scheme and structure. Drive impulses may be transmitted to an oscillating mass via torque through the support arms. For multi-axis oscillators drive signals for two or more axes may be superimposed by a driver circuit and transmitted to the MEMS oscillator. The oscillator responds in each axis according to its resonance frequency in that axis. The oscillator may be driven resonantly in some or all axes. Improved load distribution results in reduced deformation. A simplified structure offers multi-axis oscillation using a single moving body. Another structure directly drives a plurality of moving bodies. Another structure eliminates actuators from one or more moving bodies, those bodies being driven by their support arms.