Provided are an optical cavity 100 for a gas sensor which has a space therein and a gas sensor using the optical cavity, in which in the space of the optical cavity 100, an elliptical reflective surface 133, which constitutes a part of an ellipse (133, 133a) and reflects the light emitted from a position of one focal point F.sub.1 of the ellipse to concentrate the light on the other focal point F.sub.2 of the ellipse, is formed, a hyperbolic reflective surface, which constitutes a part of a hyperbola (135a, 135b) having one focal point that coincides with the other focal point of the ellipse, and reflects the light, which is reflected by the elliptical reflective surface and concentrated on the other focal point of the ellipse, to concentrate the light on the other focal point f.sub.2 of the hyperbola, is formed, and a hyperbola centerline B-B, which connects one focal point of the hyperbola and the other focal point of the hyperbola, is inclined toward a side opposite to the elliptical reflective surface by a predetermined angle with respect to an ellipse centerline A-A which connects one focal point of the ellipse and the other focal point of the ellipse.

A particle detector formed by a body defining a chamber and housing a light source and a photodetector. A reflecting surface is formed by a first reflecting region and a second reflecting region that have a respective curved shape. The curved shapes are chosen from among portions of ellipsoidal, paraboloidal, and spherical surfaces. The first reflecting region faces the light source and the second reflecting region faces the photodetector. The first reflecting region has an own first focus, and the second reflecting region has an own first focus. The first focus of the first reflecting region is arranged in an active volume of the body, designed for detecting particles, and the photodetector is arranged on the first focus of the second reflecting region.

A quality control station (2) for a sheet element processing machine, having at least one camera (6) arranged for capturing images of sheet elements (4) transported through the quality control station (2), and further having an illumination unit (5) with at least one light emitter (16) and two reflectors (12, 14), the illumination unit (5) directing light onto a viewing area of the camera (6) such that the illumination intensity is constant despite changing media thickness. An illumination unit for such quality control station is disclosed.

A spectroscopic measuring device includes a halogen lamp as a light source, a lens of an irradiating system, a mirror, and a spectrometer. The lens of the irradiating optical system emits light from the halogen lamp to a measurement object. The mirror is an optical member, and the mirror is arranged coaxial with the lens and conducts detecting light between the halogen lamp and the measurement object, to the spectrometer. The spectrometer is an analyzing part and analyzes material of the measurement object on the basis of the light received via the mirror. The light from the halogen lamp to the measurement object passes through the peripheral part of the optical axis of the lens, and the light to be received by the spectrometer passes through the center part of the optical axis of the lens, at the position of the mirror.

A small-sized gas detection apparatus with high measurement accuracy is provided. The gas detection apparatus includes a light emitting portion (1); a light receiving portion (2); a first mirror (3) that has a quadric reflective surface and reflects light emitted from the light emitting portion; and a second mirror (4) that has a quadric reflective surface and reflects the light reflected by the first mirror to the first mirror. The quadric surfaces of the first mirror and the second mirror have convex portions facing in a same direction. The first mirror reflects the light reflected by the second mirror to the light receiving portion. When one surface of a substrate on which the light emitting portion and the light receiving portion are mounted is used as a reference plane, the first mirror and the second mirror are provided at positions higher than the reference plane and have different heights.

Certain configurations are described herein of an optical spectrometer and instruments including an optical spectrometer. In some instances, the optical spectrometer is configured to spatially separate provided wavelengths of light to permit detection or imaging of each provided wavelength of light. Improved sensitivities and detection limits may be achieved using the optical spectrometers described herein.

A system and method for monitoring and operating one or more light emitting devices is disclosed. In one example, light intensity within a dual elliptical reflecting chamber is sensed and operation of a fiber curing system is adjusted in response to an amount of sensed light energy.

A container inspection system is described herein. The container inspection system includes a light source that emits a flash of light when a container is detected as being in an inspection region. The container inspection system further includes a light director element that receives a portion of the flash of light and forms a tapering field of light that illuminates an exterior surface of a sidewall of the container when the container is in the inspection region. The container inspection system further comprises a camera that generates an image of the exterior surface when such surface is illuminated by the tapering field of light. A computing system receives the image and outputs an indication as to whether or not the container is defective based upon the image.

Provided are an optical cavity 100 for a gas sensor which has a space therein and a gas sensor using the optical cavity, in which in the space of the optical cavity 100, an elliptical reflective surface 133, which constitutes a part of an ellipse (133, 133a) and reflects the light emitted from a position of one focal point F.sub.1 of the ellipse to concentrate the light on the other focal point F.sub.2 of the ellipse, is formed, a hyperbolic reflective surface, which constitutes a part of a hyperbola (135a, 135b) having one focal point that coincides with the other focal point of the ellipse, and reflects the light, which is reflected by the elliptical reflective surface and concentrated on the other focal point of the ellipse, to concentrate the light on the other focal point f.sub.2 of the hyperbola, is formed, and a hyperbola centerline B-B, which connects one focal point of the hyperbola and the other focal point of the hyperbola, is inclined toward a side opposite to the elliptical reflective surface by a predetermined angle with respect to an ellipse centerline A-A which connects one focal point of the ellipse and the other focal point of the ellipse.

A quality control station (2) for a sheet element processing machine, having at least one camera (6) arranged for capturing images of sheet elements (4) transported through the quality control station (2), and further having an illumination unit (5) with at least one light emitter (16) and two reflectors (12, 14), the illumination unit (5) directing light onto a viewing area of the camera (6) such that the illumination intensity is constant despite changing media thickness. An illumination unit for such quality control station is disclosed.