A multilayer mirror comprises a reflector section including a plurality of alternating layers of a high index material and a low index material, and a filter section over the reflector section. The filter section comprises a first filter layer including a low index material on a layer of high index material of the reflector section; a second filter layer on the first filter layer, the second filter layer comprising a high index material that is different than the high index material in the reflector section; and a third filter layer on the second filter layer, the third filter layer comprising a low index material. Each filter layer has an optical thickness greater than or equal to the optical thickness of each layer of the alternating layers. The filter section substantially blocks ultraviolet (UV) energy, thereby preventing UV energy from substantially impinging on the high index material of the reflector section.

There is provided an optical filter capable of effectively transmitting ultraviolet light in a wavelength range from 220 nm to 225 nm while suppressing the transmission of ultraviolet light in a wavelength range from 240 nm to 320 nm. An optical filter 1 includes a transparent substrate 2 and a dielectric multilayer film 3 provided on the transparent substrate 2 and containing hafnium oxide. A minimum value of spectral transmittance in a wavelength range from 220 nm to 225 nm is 50% or more with an incident angle of 0 degrees, and a maximum value of spectral transmittance in a wavelength range from 240 nm to 320 nm is 5% or less with an incident angle of 0 degrees.

The present disclosure provides an interference filter, a lithography system incorporating an interference filter, and a method of fabricating an interference filter. The interference filter includes a transparent substrate having a front surface and a back surface, a plurality of alternating material layers formed over the front surface of the transparent substrate that form a bandpass filter, and an anti-reflective structure formed over the back surface of the transparent substrate. The alternating material layers alternate between a relatively high refractive index material and a relatively low refractive index material.

An ultraviolet light irradiation device includes an optical filter. The optical filter has a transmission spectrum of zero-degree light including a first transmission band and a second transmission band that transmit the zero-degree light and a first restriction band that restricts transmission of the zero-degree light. The first transmission band is present within the wavelength band of 200 nm or more and less than 240 nm. The second transmission band is present within a wavelength band of more than 300 nm and less than 400 nm. The first restriction band is present over an entire wavelength range of at least 240 nm or more and 300 nm or less, and the first restriction band has an upper limit provided within a range of more than 300 nm and 380 nm or less.

Membranes for EUV lithography are disclosed. In one arrangement, a membrane has a stack having layers in the following order: a first capping layer including an oxide of a first metal; a base layer including a compound having a second metal and an additional element selected from the group consisting of Si, B, C and N; and a second capping layer including an oxide of a third metal, wherein the first metal is different from the second metal and the third metal is the same as or different from the first metal.

Provide is an ultraviolet ray transmissive filter in which a crystal structure of a hafnium oxide layer is controlled to improve the light resistance of an optical interference film, and which can suppress reduction of the transmissivity in a transmission band even under long-term irradiation with ultraviolet rays. The optical interference film includes the hafnium oxide layer, and in the crystal structure of the hafnium oxide layer, spectral peak intensities from X-ray diffraction which are derived from the orthorhombic crystal structure and a tetragonal crystal structure are lower than a spectral peak intensity from X-ray diffraction which is derived from the monoclinic crystal structure.

A display device may include at least one optical control unit including first refractive index layers, second refractive index layers, and an optical compensation layer. The second refractive index layers may be stacked in an alternating manner with the first refractive index layers and may have a refractive index different from that of the first refractive index layers. The optical compensation layer may be disposed at least on the uppermost refractive index layer of the first and second refractive index layers to be in contact with the uppermost refractive index layer or below the lowermost refractive index layer of the first and second refractive index layers to be in contact with the lowermost refractive index layer. The optical compensation layer may have a thickness less than those of the first and second refractive index layers.

A window unit is designed to prevent or reduce bird collisions therewith. The window unit may include first and second substrates (e.g., glass substrates) spaced apart from one another, wherein at least one of the substrates supports an ultraviolet (UV) reflecting coating for reflecting UV radiation so that birds are capable of more easily seeing the window. The UV reflecting coating is preferably patterned so that it is not provided across the entirety of the window unit. By making the window more visible to birds, bird collisions and bird deaths can be reduced. The UV reflecting coating is designed to have high UV reflectance across a large range of viewing angles.

Multilayer optical film comprising at least a plurality of alternating first and second optical layers. Embodiments of the multilayer optical film are useful, for example, in UV-C shield, UV-C light collimator, and UV-C light concentrator applications.

An optical sensor system includes a plurality of sets of optical sensors implemented on a substrate, with a plurality of sets of optical filters, wherein a set of optical filters of the plurality of sets of optical filters is associated with a set of optical sensors and a set of optical filters of the plurality of sets of optical filters includes a plurality of optical filters that are arranged in a pattern, with each optical filter of the plurality of optical filters configured to pass light in a different wavelength range of a predefined spectral range. Each set of optical filters operates to provide a bandpass response corresponding to the predefined spectral range and a set of optical filters is located atop an associated set of optical sensors, where at least two sets of optical filters of the plurality of sets of optical filters are configured to provide different bandpass responses. An optical element is associated with a corresponding set of optical sensors, with each rejection filter configured to pass light wavelengths in a predefined spectral range.