A low infrared absorbing lithium glass includes FeO in the range of 0.0005-0.015 wt %, more preferably 0.001-0.010 wt %, and a redox ratio in the range of 0.005-0.15, more preferably in the range of 0.005-010. The glass can be chemically tempered and used to provide a ballistic viewing cover for night vision goggles or scope. A method is provided to change a glass making process from making a high infrared absorbing lithium glass having FeO in the range of 0.02 to 0.04 wt % and a redox ratio in the range of 0.2 to 0.4 to the low infrared absorbing lithium glass by adding additional oxidizers to the batch materials. A second method is provided to change a glass making process from making a low infrared absorbing lithium glass to the high infrared absorbing lithium glass by adding additional reducers to the batch material. In one embodiment of the invention the oxidizer is CeO.sub.2. An embodiment of the invention covers a glass made according to the method.

A low infrared absorbing lithium glass includes FeO in the range of 0.0005-0.015 wt %, more preferably 0.001-0.010 wt %, and a redox ratio in the range of 0.005-0.15, more preferably in the range of 0.005-010. The glass can be chemically tempered and used to provide a ballistic viewing cover for night vision goggles or scope. A method is provided to change a glass making process from making a high infrared absorbing lithium glass having FeO in the range of 0.02 to 0.04 wt % and a redox ratio in the range of 0.2 to 0.4 to the low infrared absorbing lithium glass by adding additional oxidizers to the batch materials. A second method is provided to change a glass making process from making a low infrared absorbing lithium glass to the high infrared absorbing lithium glass by adding additional reducers to the batch material. In one embodiment of the invention the oxidizer is CeO.sub.2. An embodiment of the invention covers a glass made according to the method.

The disclosure relates in general to illuminated panels resembling windows, and more particularly, to a system containing a light source, a diffuser and a panel combined in such a fashion as to resemble a window, skylight or curtain wall.

An optical element may be fabricated by applying foreign or attenuating material, for example, a copper material or a material that includes copper, to a silicon dioxide thin film to form a layer that exhibits extraordinary optical absorption in the infrared wavelength region of at or about 2500-4700 nanometers. The foreign material may comprise or include a transition metal. The optical element exhibits increased accuracy and sensitivity in the infrared wavelength region of at or about 2500-4700 nanometers. The at or about 2500-4700 nanometers absorption property of the optical element can be selectively tuned to any region within this at or about 2500-4700 nanometers wavelength region. The optical element may comprise multiple layers of varying thicknesses to further tune the optical element to one or more spectral bands. Such an optical element may be utilized in a formation fluid analysis tool or an eye protection device.

Disclosed is a near-infrared filter. The near-infrared filter includes a filter-support-seat body including a quadrangular pillar cell region and a dummy region which surrounds the cell region and which is gradually reduced in size from the cell region, and an optical-filter-subdivision layer covering the cell region and the dummy region at a front side and a rear side of the filter-support-seat body based on the path of a light beam which is incident on the front side and penetrates the rear side in the filter-support-seat body. The dummy region has a chamfered side that is slanted obliquely in at least one side of the front side and the rear side of the filter-support-seat body. Further, a method of manufacturing the near-infrared filter is disclosed for each process step.

An optical filter 1a has a first transmission spectrum satisfying the following requirements (i), (ii), (iii), and (iv) at 25° C. (i) A minimum of a transmittance in a wavelength range of 450 nm to 600 nm is 70% or more. (ii) A maximum of the transmittance in a wavelength range of 300 nm to 370 nm is 5% or less. (iii) A maximum of the transmittance in a wavelength range of 800 nm to 1000 nm is 5% or less. (iv) A minimum of the transmittance in a wavelength range of 1500 nm to 1700 nm is 60% or more.

A glass has a maximum crystallization rate (KG.sub.max) of at most 0.20 μm/min in a temperature range of 700° C. to 1250° C. and a hydrolytic stability according to a hydrolytic class 1 HGA1 according to ISO 720:1985. In the case of a sample thickness of 2 mm of the glass, a ratio of a minimum transmittance in a wavelength range of 850 nm to 950 nm to a maximum transmittance in a wavelength range of 250 nm to 700 nm is in a range of 1.9:1 to 15:1.

A glass includes cations of the following components in the indicated amounts (molar proportion in cat.-%): 30-80 cat.-% silicon; 0-20 cat.-% boron; 0-2 cat.-% aluminum; 5-35 cat.-% sodium; 2-25 cat.-% potassium; 0-0.5 cat.-% nickel; 0-0.5 cat.-% chromium; and 0.03-0.5 cat.-% cobalt. A sum of the molar proportions of cations of sodium and potassium is in a range of from 15 to 50 cat.-%, a sum of the molar proportions of cations of nickel and chromium is in a range of from 0.1 to 0.5 cat.-%, and a ratio of the sum of the molar proportions of cations of sodium and potassium to the sum of the molar proportions of cations of nickel and chromium is in a range of from 70:1 to 200:1.

The invention generally relates to optical filters that provide regulation and/or enhancement of chromatic and luminous aspects of the color appearance of light to human vision, generally to applications of such optical filters, to therapeutic applications of such optical filters, to industrial and safety applications of such optical filters when incorporated, for example, in radiation-protective eyewear, to methods of designing such optical filters, to methods of manufacturing such optical filters, and to designs and methods of incorporating such optical filters into apparatus including, for example, eyewear and illuminants.

A near-infrared absorbing material fine particle dispersion, a near-infrared absorber laminate, and a laminated structure for near-infrared absorption can exhibit higher near-infrared absorption property, compared to near-infrared fine particle dispersions, near-infrared absorber laminates, and laminated structures for near-infrared absorption, containing tungsten oxides or composite tungsten oxides according to the conventional art. Also, a near-infrared absorbing material fine particle dispersion in which composite tungsten oxide fine particles, each particle containing a hexagonal crystal structure, and a polymer compound with maleic anhydride introduced therein are contained in the polypropylene resin, and the near-infrared absorber laminate and the laminated structure for near-infrared absorption using the dispersion.