Augmented, virtual, and mixed reality (XR) displays require miniature light engines that can be worn near-theeye. Laser beam scanner (LBS) architectures use light from a hermetically-sealed laser beam module (LBM) and scan the light with a MEMS mirror into a combiner. This paper presents an improved method for packaging a red, green, and blue (RGB) LBM using stamped mirror arrays that fold the light beam, correct beam shape, and redirect beam propagation to a MEMS mirror. The mirror array simplifies the optical path and eliminates passive components like dichroic filters and refractive lenses such as those used for slow-axis and fast-axis correction. This new approach reduces the size, weight, and cost of LBMs for XR applications.
High-power lasers have many applications in diverse fields such as optical communication, material processing (manufacturing), free-space optics, and 3D vision techniques such as LiDAR. These applications require optical components that alter or redirect laser beams to be tolerant to harsh environments, stable to thermal changes, and tolerant of high power levels that might otherwise damage materials or surfaces. It is common to use processes like machining, grinding, or polishing to achieve both form and finish requirements in either refractive or reflective materials. In this paper, we present a new alternative process for reflective freeform optical components suited to high-power assemblies that are made of aluminum for its thermal properties but manufactured by ultra-high precision stamping. The aluminum freeform mirrors can be used in air for free-space applications external to the laser module, or they can be assembled inside a laser diode package to provide beam shaping and redirection of the high-power beams very near the laser diode. This paper presents an exemplary optical design and thermal analyses for two cases: continuous wave (stead-state) lasers and pulsed (transient) lasers. The analyses demonstrate distinct benefits in thermal aberrations and lower operating temperatures for aluminum relative to a similar component made of a common polymer used in molded optics.
Germicidal irradiation with a dose of UV-C light is an effective method for disinfecting surfaces, water, and air. New commercial devices are abandoning mercury gas-arc lamps in favor of UV-C LEDs, but UV-C LEDs are less efficient. This requires optical designs that use lenses to deliver UV-C light with high irradiance values to the target. This paper presents metallic optical reflectors (MORs), made with stamping processes, as a new lens for UV-C LEDs. Designs are described, tested, and validated for applications in SMD packages and chip-on- board (COB) modules. Aspherical mirror surface in MORs narrow the beam and achieve viewing angles as small as 15° FWHM with high efficiency. Simulations and tests conducted with a gonio-spectroradiometer agree sufficiently well so that the optical model can be used to design germicidal irradiation systems for surfaces or air in upper-room applications.
Metallic optical benches that are useful in photonics packaging and optical interconnects can be manufactured with ultra-high precision stamping processes. They contain microscale features suitable for passive alignment of optical components. A recent innovation is the ability to stamp micro mirrors into metallic optical benches. These mirrors have finishes better than Sa = 5 nm without any secondary processes. Micro mirrors expand the utility of metallic optical benches by enabling light beams to be folded or shaped using aspherical micro mirrors that focus or expand the light beams. This is accomplished without any additional cost of refractive for diffractive lenses, and the mirrors are aligned to other bench features by the stamping process. We present exemplary metallic optical benches with micro mirror arrays for connecting optical fibers to photonic devices such as photonic integrated circuits and discrete photodiodes.
Aerostatic spindles are used in precision grinding applications requiring high stiffness and very low error motions (5 to 25 nm). Forces generated during precision grinding are small and present challenges for accurate and reliable process monitoring. These challenges are met by incorporating non-contact displacement sensors into an aerostatic spindle that are calibrated to measure grinding forces from rotor motion. Four experiments compare this force-sensing approach to acoustic emission (AE) in detecting workpiece contact, process monitoring with small depths of cut, detecting workpiece defects, and evaluating abrasive wheel wear/loading. Results indicate that force measurements are preferable to acoustic emission in precision grinding since the force sensor offers improved contact sensitivity, higher resolution, and is capable of detecting events occurring within a single revolution of the grinding wheel.
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