A frost-prevention film system of a large-aperture reflecting optic infrared telescope used in an extremely low temperature environment and a preparation method thereof is disclosed. The frost-prevention film system has the following structure: a transparent conducting film layer, an intermediate insulation layer, a reflecting film layer and an outermost medium protection layer in sequence from a main telescope mirror surface, wherein both sides of the transparent conducting film layer are provided with conducting electrodes. The steps are as follows: (1) a preparation step; (2) a step of plating a conducting film; (3) a step of plating an intermediate insulation layer; (4) a step of plating a reflecting film layer; (5) a step of plating an outermost medium protection layer; and (6) a step of plating conducting electrodes.

A hermetic seal between an optical element and a metal mount or housing using a fluoropolymer. The fluoropolymer is dispersed along the interior edge of the metal mount. The metal mount and fluoropolymer are then heated to a temperature exceeding the melting point of the fluoropolymer. Once heated the optical element is pressed into the metal mount and allowed to cool. The metal mount, optical element and thickness of fluoropolymer are sized to provide an interference fit between the metal mount and optical element.

A scanner for scanning a dental site comprises a base, a detector mounted to the base, and an optical element to redirect light reflected off of the dental site towards the detector along a detection axis in a first direction. Two or more flexures couple the optical element to the base, wherein the two or more flexures maintain an alignment of the optical element to the detector with changes in temperature.

An athermal compound lens includes a plano-concave lens and a plano-convex lens. The plano-concave lens has a first focal length, a first refractive index n.sub.1, and planar object-side surface opposite a concave image-side surface. The plano-convex lens is axially aligned with the plano-concave lens and has (i) a second focal length, (ii) a second refractive index n.sub.2, (iii) a planar image-side surface, and (iv) a convex object-side surface between the planar image-side surface and the concave image-side surface. In a free-space wavelength range and temperature range: (a) the first focal length divided by the second focal length is less than 0.68, and (b) first and second refractive indices n.sub.1 and n.sub.2 have respective temperature dependences $\frac{n_1}{T}\mathrm{and}\frac{n_2}{T}$
that satisfy

An optical cap that protects a camera lens of the inspection assembly is disclosed herein. The disclosed optical cap for an inspection assembly may include an optically clear dome-shaped window element and a metal collar attached to the window element, the collar including means for securing the optical cap to said inspection assembly, wherein the collar is bonded to the window element by means of brazing or welding.

A lightfield otoscope includes a housing with a tip configured to receive a disposable speculum. The otoscope also includes a microlens array, a sensor array and an optical train contained within the housing. The optical train includes an objective lens and a relay lens. The objective lens is positioned at least partially within the tip. The relay lens is used to relay an image plane of the objective lens to the microlens array and to relay a pupil plane of the objective lens to the sensor array. An active heating element is also contained within the housing and positioned to heat the front surface, thereby reducing fogging and/or condensation on the front surface.

Systems, apparatus and methods for performing laser operations in boreholes and other remote locations, such operations including laser drilling of a borehole in the earth, and laser workover and completion operations. Systems, apparatus and methods for generating and delivering high power laser energy below the surface of the earth and within a borehole. Laser operations using such down hole generated laser beams.

A self-locking plug assembly is provided that includes a plug, a lower clutch disposed around the plug and defining engagement features, an upper clutch disposed around the plug and defining mating engagement features, a resilient member and a cap surrounding the resilient member and disposed around a proximal end portion of the plug. The mating engagement features are configured to apply higher torque to the engagement features in one direction than in an opposite direction. In one form, the engagement features of the lower clutch and upper clutch comprise a plurality of teeth arranged around a central aperture.

An imaging system includes a lighting controller for independently controlling emission of illumination light to be emitted by a light source in: (i) a non-all-line exposure period, which contains a reading period in which electrical signals are sequentially read out on a horizontal-line basis from an image sensor for one frame or one field period, and in which at least one horizontal line of the horizontal lines for the one frame or the one field period is not exposed to light, and (ii) in an all-line exposure period, in which all of the horizontal lines for the one frame or the one field period are exposed to light.

A hermetic seal between an optical element and a metal mount or housing using a fluoropolymer. The fluoropolymer is dispersed along the interior edge of the metal mount. The metal mount and fluoropolymer are then heated to a temperature exceeding the melting point of the fluoropolymer. Once heated the optical element is pressed into the metal mount and allowed to cool. The metal mount, optical element and thickness of fluoropolymer are sized to provide an interference fit between the metal mount and optical element.