A droplet sensor includes an optical cover having a curved surface that forms a part of a spheroid, a protective film that covers the curved surface of the optical cover, a light source provided at a first focal point of an ellipse facing the curved surface, and a photodetector provided at a second focal point of the ellipse. The refractive index of the protective film is greater than the refractive index of a liquid to be detected. A sensing region is determined by a range of an incident angle at which a light beam emitted from the light source and incident onto the curved surface is totally reflected at the interface between the protective film and a gas, and is not totally reflected at the interface between the protective film and the liquid to be detected.

Provided are a diffusion plate that diffuses light emitted from a light source, and a prism having a first surface to receive the light transmitted through the diffusion plate, a second surface to reflect the light in contact with a measurement target liquid, and a third surface to extract the reflected light. The light source, the diffusion plate, a light receiving lens, and an imaging element are accommodated in a holder that presses the prism from the inner side to the outer side.

A prism for measuring liquid concentration includes: an accommodating space for accommodating a liquid; an interface formed on a bottom surface of the accommodating space; a first light transmission surface and a second light transmission surface respectively formed on two side surfaces of the accommodating space; a third light transmission surface and a light emitting surface respectively formed relative to the interface. When a first incident light beam enters the prism, the first incident light beam is reflected to the light emitting surface by the interface, and exits the prism from the light emitting surface. When a second incident light beam enters the prism to the first light transmission surface, the second incident light beam exits the prism to the accommodating space from the second incident light beam, passes through the liquid and the second light to the prism, and exits the prism from the third light transmission surface.

A prism for measuring liquid concentration includes: an accommodating space for accommodating a liquid; an interface formed on a bottom surface of the accommodating space; a first light transmission surface and a second light transmission surface respectively formed on two side surfaces of the accommodating space; a third light transmission surface and a light emitting surface respectively formed relative to the interface. When a first incident light beam enters the prism, the first incident light beam is reflected to the light emitting surface by the interface, and exits the prism from the light emitting surface. When a second incident light beam enters the prism to the first light transmission surface, the second incident light beam exits the prism to the accommodating space from the second incident light beam, passes through the liquid and the second light to the prism, and exits the prism from the third light transmission surface.

The disclosure proposes a portable fiber optic measurement device (100) for physical, chemical, and biological sensing applications that facilitates real-time monitoring. The device (100) includes a fiber optic probe cartridge (120) that is removably attached to a measuring device (110). The device (110) includes a light source, a detector, and the associated electronic measurement and control unit along with a display. The device (100) is configured to measure the real-time changes in the light intensity on the fiber probe cartridge side (130). With a U-bent fiber optic probe cartridge (138) as an example, the device (100) is configured to measure the bulk solution refractive index changes, effective refractive index change, or characteristic optical property of analytes including ions, chemical and bio molecules, polymers, compounds, microorganisms present on the fiber core surface (138). The key facets of this device include high sensitivity, real-time and rapid analysis, handheld, and portable instrumentation at meager operational cost.

Methods and apparatus for obtaining a corrected digital mode spectrum for a chemically strengthened (CS) substrate having a curved surface are disclosed. The methods include digitally capturing transverse magnetic (TM) and transverse electric (TE) mode spectra of the CS substrate to form a digital mode spectrum image using an evanescent prism coupling system having a system calibration for measuring flat CS substrates. The method further includes establishing a calibration correction based on the difference in the digitally captured TM and TE mode spectra as compared to a reference TM and TE mode spectra for a reference CS substrate. The calibration correction is applied to the digital mode spectrum image to form the corrected digital mode spectrum image, which can be processed using the system calibration for measuring flat CS substrates to determine a refractive index profile and stress characteristics for the curved CS substrate.

A method for determining a residual retardance of an LCOS (Liquid Crystal on Silicon) panel includes transmitting a light beam to the LCOS panel at an angle of incidence and measuring an intensity of a reflected light beam. The method includes biasing the LCOS panel in a dark state and measuring a dark state intensity of the reflected light beam. The method also includes biasing the LCOS panel in a bright state, and measuring a bright state intensity of the reflected light beam. A residual retardance of the LCOS panel is determined based on a contrast ratio of the bright state intensity and the dark state intensity. The method can also include selecting a compensator for the LCOS panel based on the residual retardance.

A method for determining a residual retardance of an LCOS (Liquid Crystal on Silicon) panel includes transmitting a light beam to the LCOS panel at an angle of incidence and measuring an intensity of a reflected light beam. The method includes biasing the LCOS panel in a dark state and measuring a dark state intensity of the reflected light beam. The method also includes biasing the LCOS panel in a bright state, and measuring a bright state intensity of the reflected light beam. A residual retardance of the LCOS panel is determined based on a contrast ratio of the bright state intensity and the dark state intensity. The method can also include selecting a compensator for the LCOS panel based on the residual retardance.

The invention concerns an apparatus for determining a secondary image angle (20) of a light source (11) on a transparent object (14). To achieve the objective of building a simple apparatus and to determine the secondary image angle (20) with higher measuring point densities even on transparent objects (14) with large surfaces in a quick, reliable manner with few movements, the apparatus includes an illuminating device (10), which has multiple, simultaneously illuminating, punctiform light sources (11), a two-dimensional target (16a) with at least one camera (16), whereby at least one camera (16) is set up to capture the positions of a primary image (21a) and a secondary image (21b) of multiple simultaneously illuminating light sources (11) at the same time, whereby the primary image (21) and the secondary image (21b) of one light source (11) are generated on the target by one of the volume elements (14a) of the transparent object illuminated by the light source (11), and an evaluation device (18) is set up to determine the secondary image angle (20) of the respective volume element (14a) of the transparent object (14) based on the positions of the primary image (21a) and the secondary image (21b). Furthermore, a method for determining the secondary image angle is also specified.

The invention concerns an apparatus for determining a secondary image angle (20) of a light source (11) on a transparent object (14). To achieve the objective of building a simple apparatus and to determine the secondary image angle (20) with higher measuring point densities even on transparent objects (14) with large surfaces in a quick, reliable manner with few movements, the apparatus includes an illuminating device (10), which has multiple, simultaneously illuminating, punctiform light sources (11), a two-dimensional target (16a) with at least one camera (16), whereby at least one camera (16) is set up to capture the positions of a primary image (21a) and a secondary image (21b) of multiple simultaneously illuminating light sources (11) at the same time, whereby the primary image (21) and the secondary image (21b) of one light source (11) are generated on the target by one of the volume elements (14a) of the transparent object illuminated by the light source (11), and an evaluation device (18) is set up to determine the secondary image angle (20) of the respective volume element (14a) of the transparent object (14) based on the positions of the primary image (21a) and the secondary image (21b). Furthermore, a method for determining the secondary image angle is also specified.