A honeycomb sandwich panel having an absolute value of thermal expansion coefficient smaller than an absolute value of thermal expansion coefficient obtained by using carbon fiber reinforced plastic (CFRP) is provided. The honeycomb sandwich panel includes: a first skin being a plate material made of a low expansion metal being a metal having an absolute value of thermal expansion coefficient smaller than an absolute value of thermal expansion coefficient of CFRP; a second skin being a plate material made of the low expansion metal and arranged to face the first skin; and a core made of CFRP or the low expansion metal, being bonded to the first skin and the second skin and including a plurality of tubular cells each having a hexagonal cross section, the tubular cells being formed adjacently to each other.

An apparatus, system, and computer-implemented method that correct for thermal drift in one or more optical elements in an optical device and maintain high precision accuracy of the optical device during extreme temperature changes. The apparatus includes an optical device having an optical element configured to direct or reflect a light beam, a pivot support configured to hold a portion of the optical element and facilitate motion of the optical element in multidimensional space, a controller configured to determine a displacement of the optical element due to thermal drift and generate an actuator drive signal based on the amount of the displacement, and an actuator configured to receive the actuator drive signal and counteract the thermal drift by moving, in cooperation with the pivot support and in response to the actuator drive signal, the optical element by an inverse amount and direction of the displacement of the optical element.

According to one implementation a mount pad is provided that includes a plurality of arcuate flexure members disposed between and connected to top and bottom plates. According to some implementations a majority or all of the arcuate flexure members have a semi-circular cross-section and are arranged to form a plurality of radially spaced-apart concentric rings. Concave surfaces of the arcuate flexure members face radially inward toward a center of the concentric rings. Circumferential adjacent arcuate flexure members in each of the concentric rings are circumferentially spaced apart from one another so that a gap exists between them. According to some implementations the mount pad further includes a coupling unit prolonging from one of the top and bottom plates, the coupling unit facilitating a connection of the mount pad to a support structure. According to some implementations the mount pad is a monolithic structure. According to some implementations the monolithic structure is made using an additive manufacturing method.

A mirror holding structure includes: a holder; at least one protrusion part provided to one of a mirror body and the holder; at least one reception part provided to the other of the mirror body and the holder and having an insertion hole in which the at least one protrusion part is to be inserted; and at least one elastic part located between an outer peripheral surface of the at least one protrusion part and an inner peripheral surface of the insertion hole and being elastic.

An improved mount for, and method of mounting an, optical structure is provided. The mount has an optical structure comprising at least one mirror panel, the mirror panel comprising a reflective surface and a back surface substantially opposite the reflective surface, a protruding member extending from the back surface of the optical structure, the protruding member having a shape and the shape having an outside surface there-around, a base comprising a mounting element and an upper element extending from the mounting element, the upper element having a cavity for secured receipt therein of at least a portion of the protruding member, wherein the receiving cavity of the upper element has a shape identical to that of the shape of the protruding member, but where the shape of the protruding member is ten thousandths ( 1/10,000) of an inch smaller than the shape of the receiving cavity so that the outside surface of the protruding member is ten thousandths ( 1/10,000) of an inch away from the corresponding parts of the receiving cavity when the protruding member is secured within the cavity.

The disclosure provides an arrangement for the thermal actuation of a mirror, in particular in a microlithographic projection exposure apparatus, as well as related methods and systems.

A fixing structure for fixing a reflector and a device for detecting a display brightness are provided. The fixing structure is configured to fix a reflector to a photosensitive detecting assembly; and the fixing structure includes at least one clamping unit configured to clamp and fix the reflector. Each clamping unit includes: a first support, including a first clamping arm configured to support a first surface of the reflector; and a second support, including a second clamping arm configured to press on a second surface of the reflector facing away from the first surface.

An electro-optic device includes a chip provided with a mirror and a drive element adapted to drive the mirror, a light-transmitting cover adapted to cover the mirror in a planar view, and a spacer having contact with one surface of the chip between the cover and the chip. The entire part of one surface of the chip having contact with the spacer is made of a first material such as silicon oxide film having first thermal conductivity, and the spacer is made of a second material such as a quartz crystal having second thermal conductivity higher than the first thermal conductivity. The cover is made of a third material such as sapphire having third thermal conductivity higher than the second thermal conductivity.

A flexure including a bipod strut pair extending from a base and a titanium-zirconium-niobium alloy, which includes titanium, about 13.5 to about 14.5 wt. % zirconium, and about 18 to about 19 weight % (wt. %) niobium. The titanium-zirconium-niobium alloy has a congruent melting temperature of about 1750 to about 1800° Celsius (° C.).

A mirror mounting member is formed of a ceramic structure with a prismatic or angular cylindrical shape and includes, as outer surfaces, a joining surface configured to join to a to-be-joined surface, and an inclined surface inclined relative to the joining surface. The inclined surface is a mounting surface on which is mounted a reflective film that reflects light emitted from a light source. The joining surface includes a plurality of first grooves extending in a longitudinal direction of the structure and a plurality of second grooves intersecting the first grooves. The first grooves are open at both ends, and the second grooves are sealed at an end portion located on a side where light is reflected by the reflective film.