Abstract: Disclosed is an apparatus and method for heat treating glass sheets, and in particular for heat treating very thing glass sheets arranged in closely spaced stacks. The glass sheets are positioned on a moving belt such that their major surfaces are substantially perpendicular to a direction of belt travel through the apparatus to aid in producing a uniform temperature profile within the glass sheets. The apparatus comprises air curtains positioned at the inlet and outlet of the apparatus to minimize the ingress of particulate into the apparatus. A reduced velocity of heated air flow within a lower portion of the apparatus relative to a velocity of the heated air in an upper portion of the apparatus causes particulate to drop out of the lower portion air flow. A rotating brush and vacuums positioned adjacent a lower portion of the belt assist in removing particulate from the moving belt.

Abstract: Disclosed is an apparatus and method for heat treating glass sheets, and in particular for heat treating very thing glass sheets arranged in closely spaced stacks. The glass sheets are positioned on a moving belt such that their major surfaces are substantially perpendicular to a direction of belt travel through the apparatus to aid in producing a uniform temperature profile within the glass sheets. The apparatus comprises air curtains positioned at the inlet and outlet of the apparatus to minimize the ingress of particulate into the apparatus. A reduced velocity of heated air flow within a lower portion of the apparatus relative to a velocity of the heated air in an upper portion of the apparatus causes particulate to drop out of the lower portion air flow. A rotating brush and vacuums positioned adjacent a lower portion of the belt assist in removing particulate from the moving belt.

Abstract: A method of making below 250-nm UV light transmitting optical fluoride lithography crystals includes applying heat along a shortest path of conduction of a selected optical fluoride crystal, heating the optical fluoride crystal to an annealing temperature, holding the temperature of the optical fluoride crystal at the annealing temperature, and gradually cooling the optical fluoride crystal to provide a low-birefringence optical fluoride crystal for transmitting below 250-nm UV light.

Abstract: A method of making below 250-nm UV light transmitting optical fluoride lithography crystals includes applying heat along a shortest path of conduction of a selected optical fluoride crystal, heating the optical fluoride crystal to an annealing temperature, holding the temperature of the optical fluoride crystal at the annealing temperature, and gradually cooling the optical fluoride crystal to provide a low-birefringence optical fluoride crystal for transmitting below 250-nm UV light.

Abstract: A method of making below 250-nm UV light transmitting optical fluoride lithography crystals includes applying heat along a shortest path of conduction of a selected optical fluoride crystal, heating the optical fluoride crystal to an annealing temperature, holding the temperature of the optical fluoride crystal at the annealing temperature, and gradually cooling the optical fluoride crystal to provide a low-birefringence optical fluoride crystal for transmitting below 250-nm UV light.

Abstract: A method of making below 250-nm UV light transmitting optical fluoride lithography crystals includes applying heat along a shortest path of conduction of a selected optical fluoride crystal, heating the optical fluoride crystal to an annealing temperature, holding the temperature of the optical fluoride crystal at the annealing temperature, and gradually cooling the optical fluoride crystal to provide a low-birefringence optical fluoride crystal for transmitting below 250-nm UV light.