An optical apparatus includes a diffractive optical element (DOE), having at least one optical surface, a side surface, which is not parallel to the at least one optical surface of the DOE, and a grating, which is formed on the at least one optical surface so as to receive and diffract first radiation from a primary radiation source that is incident on the grating. The apparatus further includes at least one secondary radiation source, which is configured to direct second radiation to impinge on the side surface, causing at least part of the second radiation to propagate within the DOE while diffracting internally from the grating and to exit through the side surface. The apparatus also includes at least one radiation detector, which is positioned so as to receive and sense an intensity of the second radiation that has exited through the side surface.

A method for detecting damage to a converter device of a lighting apparatus is provided. The method may include irradiating the converter device with input light, detecting a useful light portion emitted principally by a first section of the converter device by means of a first sensor element. A first detection signal is obtained, detecting a useful light portion emitted principally by a second section of the converter device, said second section being different than the first section, by means of a second sensor element. A second detection signal is obtained. The method further may include automatically obtaining damage information about the converter device from a ratio or a difference of the first detection signal with respect to either the second detection signal or a comparison signal formed therefrom.

A method for inspecting a spatial light modulator includes: performing such control that in an inspection target area in an array of mirror elements, the mirror elements in a first state in which incident light is given a phase change amount of 0 and the mirror elements in a second state in which incident light is given a phase change amount of 180 () become arrayed in a checkered pattern; guiding light having passed the inspection target area to a projection optical system with a resolution limit coarser than a width of an image of one mirror element, to form a spatial image; and inspecting a characteristic of the spatial light modulator from the spatial image. This method allows us to readily perform the inspection of the characteristic of the spatial light modulator having the array of optical elements.

Methods and apparatus for evaluating the geometric properties of optical fiber preforms, which methods include: providing an optical fiber preform having a longitudinal axis, an outer diameter and a circumference; providing a two-dimensional pattern having a length parallel to the longitudinal axis of the preform and a width greater than the outer diameter of the preform; providing an image capturing device disposed such that the preform is aligned between the pattern and the image capturing device; rotating the preform about its longitudinal axis and acquiring a first plurality of images of the pattern viewed through the preform at at least two different points along the circumference of the preform; and determining at least one geometric property of the preform from the first plurality of images.

In a conductive film, a method of evaluating a pattern in the conductive film, and a display device, thin metal lines of at least one wiring portion of two wiring portions is formed in a wiring pattern where the opening portions, of which angles are maintained and pitches are made to be irregular with respect to rhomboid shapes of a regular rhomboid wiring pattern, have parallelogram shapes. In frequencies of the moirs that are equal to or less than a frequency threshold value and are calculated for each color from two peak frequencies and two peak intensities of 2DFFT spectra of image data of the wiring patterns of the two wiring portions and luminance image data of pixel array patterns of the respective colors at the time of lighting up for each single color, the wiring patterns of the two wiring portions are formed such that an indicator of evaluation of moirs is equal to or less than an evaluation threshold value. The indicator of evaluation is calculated from evaluation values of the moirs of the respective colors obtained by applying human visual response characteristics in accordance with an observation distance to intensities of the moirs equal to or greater than an intensity threshold value.

A laser system includes a nonlinear optical (NLO) crystal, wherein the NLO crystal is annealed within a selected temperature range. The NLO crystal is passivated with at least one of hydrogen, deuterium, a hydrogen-containing compound or a deuterium-containing compound to a selected passivation level. The system further includes at least one light source, wherein at least one light source is configured to generate light of a selected wavelength and at least one light source is configured to transmit light through the NLO crystal. The system further includes a crystal housing unit configured to house the NLO crystal.

A method for inspecting a spatial light modulator includes: performing such control that in an inspection target area in an array of mirror elements, the mirror elements in a first state in which incident light is given a phase change amount of 0 and the mirror elements in a second state in which incident light is given a phase change amount of 180 () become arrayed in a checkered pattern; guiding light having passed the inspection target area to a projection optical system with a resolution limit coarser than a width of an image of one mirror element, to form a spatial image; and inspecting a characteristic of the spatial light modulator from the spatial image. This method allows us to readily perform the inspection of the characteristic of the spatial light modulator having the array of optical elements.

An optical inspection device for an optical performance test of a display device including a lens part configured to transmit external light, a phase film part configured to change a phase difference of the external light and transmit the external light, and an image processor configured to obtain electrical information of the external light, in which a phase difference of the phase film part is at least 7000 nm.

An apparatus includes a lighting unit configured to irradiate a light emitting device package including a light transmitting resin containing a light conversion material with light having a certain color; a camera configured to capture an image of the light emitting device package; and a controller configured to determine color coordinates of the light emitting device package using the image, captured by the camera, to determine whether the light emitting device package is defective.

A device comprises a housing, a detector for receiving solar irradiance and for providing a detector signal providing an indication of an amount of solar irradiance received by the detector and a shield transparent to at least part of the solar irradiance to be detected, the shield and the housing providing a detector space for housing at least part of the detector. The device further comprises a first light source for emitting light to the shield and a first light sensor arranged to receive light from the first light source, arranged to provide a first signal providing an indication for an amount of light received by the first light sensor. Particles will and reflect light back to the detector space. The reflected light is received by the light sensor. Hence, a signal generated by the sensor is an indication for pollution of the shield.