Abstract: An electronic device may have a pixel array. A light source may illuminate the pixel array to produce image light. The image light may pass through a multi-element lens and may be coupled into a waveguide using an input coupler such as a prism. An output coupler such as a diffraction grating may couple the image light out of the waveguide and towards a user. The user may view the image light and may observe real-world objects through the waveguide. The waveguide may have locally modified portions that define an aperture stop at a distance from an exit surface of the multi-element lens. The multi-element lens may have first and second achromatic doublets and first and second singlets between the first and second achromatic doublets. The lens elements of the multi-element lens may include lens elements with aspheric surfaces.

Abstract: An electronic device may have a pixel array. A light source may illuminate the pixel array to produce image light. The image light may pass through a multi-element lens and may be coupled into a waveguide using an input coupler such as a prism. An output coupler such as a diffraction grating may couple the image light out of the waveguide and towards a user. The user may view the image light and may observe real-world objects through the waveguide. The waveguide may have locally modified portions that define an aperture stop at a distance from an exit surface of the multi-element lens. The multi-element lens may have first and second achromatic doublets and first and second singlets between the first and second achromatic doublets. The lens elements of the multi-element lens may include lens elements with aspheric surfaces.

Abstract: An electronic device may have a pixel array. A light source may illuminate the pixel array to produce image light. The image light may pass through a multi-element lens and may be coupled into a waveguide using an input coupler such as a prism. An output coupler such as a diffraction grating may couple the image light out of the waveguide and towards a user. The user may view the image light and may observe real-world objects through the waveguide. The waveguide may have locally modified portions that define an aperture stop at a distance from an exit surface of the multi-element lens. The multi-element lens may have first and second achromatic doublets and first and second singlets between the first and second achromatic doublets. The lens elements of the multi-element lens may include lens elements with aspheric surfaces.

Abstract: An electronic device may have a pixel array. A light source may illuminate the pixel array to produce image light. The image light may pass through a multi-element lens and may be coupled into a waveguide using an input coupler such as a prism. An output coupler such as a diffraction grating may couple the image light out of the waveguide and towards a user. The user may view the image light and may observe real-world objects through the waveguide. The waveguide may have locally modified portions that define an aperture stop at a distance from an exit surface of the multi-element lens. The multi-element lens may have first and second achromatic doublets and first and second singlets between the first and second achromatic doublets. The lens elements of the multi-element lens may include lens elements with aspheric surfaces.

Abstract: A stylus can be provided with an on-board display that indicates to a user a color that will be applied when operating the stylus with an external device. The display on the stylus can be positioned to conveniently provide an indication of the color. For example, the display can be provided at or near a tip that is used to contact the external device. The stylus can further provide an ability for the user to manually select a color, which can then be shown on the display of the stylus and transmitted to the external device for application. The stylus can further include an ability to scan a color from a physical object, with the color being shown on the display of the stylus and transmitted to the external device for application.

Abstract: A system and method to obtain correct gas density and flux measurements using (i) gas analyzer (open-path, or closed-path gas analyzers with short intake tube, or any combination of the two); (ii) fast temperature or sensible heat flux measurement device (such as, fine-wire thermocouple, sonic anemometer, or any other device providing fast accurate gas temperature measurements); (iii) fast air water content or latent heat flux measurement device (such as, hygrometer, NDIR analyzer, any other device providing fast accurate gas water content measurements); (iv) vertical wind or sampling device (such as sonic anemometer, scintillometer, or fast solenoid valve, etc.) and (v) algorithms in accordance with the present invention to compute the corrected gas flux, compensated for T-P effects. In case when water factor in T-P effects is negligible, the fast air water content or latent heat flux measurement device (item iii in last paragraph) can be excluded.

Abstract: A multi-pass optical cell with an actuator for actuating a reflective surface is provided. In one preferred embodiment, an apparatus is provided comprising a first reflective surface, a second reflective surface, and a support structure supporting the first and second reflective surfaces. The support structure positions the first and second reflective surfaces to create an optical cell. The apparatus also comprises a source and a detector, which are positioned such that light emitted from the source is reflected in the optical cell at least one time between the first and second reflective surfaces before reaching the detector. The apparatus further comprises an actuator coupled with and operative to actuate the first reflective surface. In some embodiments, the actuator rotates the first reflective surface. Also, in some embodiments, the multi-pass optical cell is an open path multi-pass optical cell, while, in other embodiments, the multi-pass optical cell is a closed path multi-pass optical cell.

Abstract: Disclosed embodiments of the present invention provide means to obtain correct gas density and flux measurements using (i) gas analyzer (open-path, or closed-path gas analyzers with short intake tube, for example 1 m long, or any combination of the two); (ii) fast temperature or sensible heat flux measurement device (such as, fine-wire thermocouple, sonic anemometer, or any other device providing fast accurate gas temperature measurements); (iii) fast air water content or latent heat flux measurement device (such as, hygrometer, NDIR analyzer, any other device providing fast accurate gas water content measurements); (iv) vertical wind or sampling device (such as sonic anemometer, scintillometer, or fast solenoid valve, etc.) and (v) algorithms in accordance with the present invention to compute the corrected gas flux, compensated for T-P effects.

Abstract: A multi-pass optical cell with an actuator for actuating a reflective surface is provided. In one preferred embodiment, an apparatus is provided comprising a first reflective surface, a second reflective surface, and a support structure supporting the first and second reflective surfaces. The support structure positions the first and second reflective surfaces to create an optical cell. The apparatus also comprises a source and a detector, which are positioned such that light emitted from the source is reflected in the optical cell at least one time between the first and second reflective surfaces before reaching the detector. The apparatus further comprises an actuator coupled with and operative to actuate the first reflective surface. In some embodiments, the actuator rotates the first reflective surface. Also, in some embodiments, the multi-pass optical cell is an open path multi-pass optical cell, while, in other embodiments, the multi-pass optical cell is a closed path multi-pass optical cell.

Abstract: A multi-pass optical cell with an actuator for actuating a reflective surface is provided. In one preferred embodiment, an apparatus is provided comprising a first reflective surface, a second reflective surface, and a support structure supporting the first and second reflective surfaces. The support structure positions the first and second reflective surfaces to create an optical cell. The apparatus also comprises a source and a detector, which are positioned such that light emitted from the source is reflected in the optical cell at least one time between the first and second reflective surfaces before reaching the detector. The apparatus further comprises an actuator coupled with and operative to actuate the first reflective surface. In some embodiments, the actuator rotates the first reflective surface. Also, in some embodiments, the multi-pass optical cell is an open path multi-pass optical cell, while, in other embodiments, the multi-pass optical cell is a closed path multi-pass optical cell.

Abstract: Disclosed embodiments of the present invention provide means to obtain correct gas density and flux measurements using (i) gas analyzer (open-path, or closed-path gas analyzers with short intake tube, for example 1 m long, or any combination of the two); (ii) fast temperature or sensible heat flux measurement device (such as, fine-wire thermocouple, sonic anemometer, or any other device providing fast accurate gas temperature measurements); (iii) fast air water content or latent heat flux measurement device (such as, hygrometer, NDIR analyzer, any other device providing fast accurate gas water content measurements); (iv) vertical wind or sampling device (such as sonic anemometer, scintillometer, or fast solenoid valve, etc.) and (v) algorithms in accordance with the present invention to compute the corrected gas flux, compensated for T-P effects.

Abstract: Disclosed embodiments of the present invention provide means to obtain correct gas density and flux measurements using (i) gas analyzer (open-path, or closed-path gas analyzers with short intake tube, for example 1 m long, or any combination of the two); (ii) fast temperature or sensible heat flux measurement device (such as, fine-wire thermocouple, sonic anemometer, or any other device providing fast accurate gas temperature measurements); (iii) fast air water content or latent heat flux measurement device (such as, hygrometer, NDIR analyzer, any other device providing fast accurate gas water content measurements); (iv) vertical wind or sampling device (such as sonic anemometer, scintillometer, or fast solenoid valve, etc.) and (v) algorithms in accordance with the present invention to compute the corrected gas flux, compensated for T-P effects.