Abstract: An optical system includes a reflective polarizer (20), and a display (10), first mirror (30a), and second mirror (30b) disposed on a same side of the reflective polarizer (20). The reflective polarizer (20) transmits an image emitted by the display (10) after the image is reflected by the first and second mirrors (30a, 30b). A mid-plane defined by intersection points between an optical axis of the system and the display (10), reflective polarizer (20), and second mirror (30b) has one-pass through four-pass regions having respective areas, A1 through A4.

Abstract: An optical system, including a reflective polarizer, and a display and a mirror disposed on a same side of, and generally facing, the reflective polarizer. The reflective polarizer may transmit at least 80% of incident light having a first polarization state and may reflect at least 80% of incident light having a second polarization state, and the mirror may reflect at least 80% of the incident light for each of the first and second polarization states. The central locations of the display, reflective polarizer, and mirror may define a midplane which includes first, second, and third regions, such that the first region includes portions of the image rays that pass at least once across the region, the second region includes portions of the image rays that pass at least twice across the region, and the third region includes portions of the image rays that pass three times across the region.

Abstract: A system for use in wirelessly monitoring a pipeline such as a natural gas pipe. The system includes a locator configured to wirelessly transmit power and a subsoil sensor marker located adjacent the pipe and configured to wirelessly communicate with the locator. The sensor marker includes a microcontroller, a memory module, a sensor configured to sense the presence of a gas, and a power module. The power module is configured to harvest a sufficient amount of the power wirelessly transmitted from the locator in order to operate the microcontroller to take a measurement via the sensor, save the measurement in the memory module, and wirelessly transmit the measurement to the locator.

Abstract: Projection subsystems are described. More, particularly, projection subsystems that include a light source and a polarizing beam splitter are described. The polarizing beam splitters of the presently described projection subsystems are capable of avoiding performance degradation even after exposure to large doses of incident light.

Abstract: Magneto-Mechanical Resonator Sensor with Mass Distribution Channel Some aspects of the present disclosure feature a sensing device (e.g. for temperature, moisture or detection of substances) comprising a magnetic bias layer, a resonator, a spacer, and an environmental change receptor. The spacer is disposed between the magnetic bias layer and the resonator. At least one of the resonator surfaces has a predefined channel. The environmental change receptor is disposed proximate to the predefined channel. In response to a change in environment, the environmental change receptor distributes along a part of the channel.

Abstract: Some aspects of the present disclosure feature a sensing device comprising a magnetic bias layer, a resonator, a spacer, and an environmental change receptor. The environmental change receptor is disposed on a surface of the resonator. The mass of the environmental change receptor is changed in response to a change in environment. The resonant frequency of the sensing device shifts in response to the mass change of the environmental change receptor.

Abstract: Resonant acoustic gas sensors and methods for operating acoustic gas sensors that improve detection and reduce power consumption through the use of dynamic thresholds for identifying resonance peaks and optimizing searching for subsequent resonance peaks. The resonant acoustic gas sensors may use one or two separate transducers to produce the electronic signal that is filtered and used to identify the resonance peaks, using either voltage or impedance values to identify resonance peaks and use the resonance peaks to determine the composition of the gas mixture being measured.

Abstract: Some aspects of the present disclosure feature a system for sensing a change in environment comprising a MMR sensor and a reader. The MMR sensor is configured to be disposed in the environment. The MMR sensor comprises a magnetic bias layer, a resonator, a spacer, and an environmental change receptor. The reader is configured to measure a frequency characteristic of the MMR sensor after the environmental variable changes and the change to the environmental variable is evaluated based on the frequency characteristic.

Abstract: A system for use in wirelessly monitoring a pipeline such as a natural gas pipe. The system includes a locator configured to wirelessly transmit power and a subsoil sensor marker located adjacent the pipe and configured to wirelessly communicate with the locator. The sensor marker includes a microcontroller, a memory module, a sensor configured to sense the presence of a gas, and a power module. The power module is configured to harvest a sufficient amount of the power wirelessly transmitted from the locator in order to operate the microcontroller to take a measurement via the sensor, save the measurement in the memory module, and wirelessly transmit the measurement to the locator.

Abstract: The disclosure generally relates to beamsplitters useful in color combiners, and in particular color combiners useful in small size format projectors such as pocket projectors. The disclosed beamsplitters and color combiners include a tilted dichroic reflective polarizer plate having at least two dichroic reflective polarizers tilted at different angles relative to incident light beams, with light collection optics to combine at least two colors of light.

Abstract: Projection subsystems are described. More, particularly, projection subsystems that include a light source and a polarizing beam splitter are described. The polarizing beam splitters of the presently described projection subsystems are capable of avoiding performance degradation even after exposure to large doses of incident light.

Abstract: Projection subsystems are described. More, particularly, projection subsystems that include a light source and a polarizing beam splitter are described. The polarizing beam splitters of the presently described projection subsystems are capable of avoiding performance degradation even after exposure to large doses of incident light.

Abstract: The disclosure generally relates to beamsplitters useful in color combiners, and in particular color combiners useful in small size format projectors such as pocket projectors. The disclosed beamsplitters and color combiners include a tilted dichroic reflective polarizer plate having at least two dichroic reflective polarizers tilted at different angles relative to incident light beams, with light collection optics to combine at least two colors of light.

Abstract: The disclosure generally relates to beamsplitters useful in color combiners, and in particular color combiners useful in small size format projectors such as pocket projectors. The disclosed beamsplitters and color combiners include a tilted dichroic reflective polarizer plate having at least two dichroic reflective polarizers tilted at different angles relative to incident light beams, with light collection optics to combine at least two colors of light.

Abstract: Some aspects of the present disclosure feature a sensing device (e.g. for temperature, moisture or detection of substances) comprising a magnetic bias layer, a resonator, a spacer, and an environmental change receptor. The spacer is disposed between the magnetic bias layer and the resonator. At least one of the resonator surfaces has a predefined channel. The environmental change receptor is disposed proximate to the predefined channel. In response to a change in environment, the environmental change receptor distributes along a part of the channel.

Abstract: Some aspects of the present disclosure feature a sensing device comprising a magnetic bias layer, a resonator, a spacer, and an environmental change receptor. The environmental change receptor is disposed on a surface of the resonator. The mass of the environmental change receptor is changed in response to a change in environment. The resonant frequency of the sensing device shifts in response to the mass change of the environmental change receptor.

Abstract: Some aspects of the present disclosure feature a system for sensing a change in environment comprising a MMR sensor and a reader. The MMR sensor is configured to be disposed in the environment. The MMR sensor comprises a magnetic bias layer, a resonator, a spacer, and an environmental change receptor. The reader is configured to measure a frequency characteristic of the MMR sensor after the environmental variable changes and the change to the environmental variable is evaluated based on the frequency characteristic.

Abstract: Projection subsystems are described. More, particularly, projection subsystems that include a light source and a polarizing beam splitter are described. The polarizing beam splitters of the presently described projection subsystems are capable of avoiding performance degradation even after exposure to large doses of incident light.

Abstract: Projection subsystems are described. More, particularly, projection subsystems that include a light source and a polarizing beam splitter are described. The polarizing beam splitters of the presently described projection subsystems are capable of avoiding performance degradation even after exposure to large doses of incident light.

Abstract: Projection lens having improved properties such as a high throughput are described. In one embodiment, a projection lens is described comprising in sequential order from a screen side a first lens group, a second lens group of positive refractive power, and a third lens group of positive refractive power. At least one lens group has an aspheric surface. The ratio of the focal length of the projection lens (F) to the focal length of each of the lens groups (F1, F2, and F3) is such that |F1/F|>5, 0.5<|F2/F|<0.9, and 1<F3/F<8. In another embodiment, a projection lens is described comprising in sequential order from a screen side a first lens group, a second lens group of positive refractive power, and a third lens group of positive refractive power. At least one lens group has an aspheric surface. The ratio of the focal length of the projection lens (F) to the focal length of each of the lens groups (F1, F2, and F3) is such that |F1/F|>5, 0.5<|F2/F|<2.0, and 1.4<F3/F<8.