Abstract: Ceramic is molded to produce a molded ceramic product, using a mold that has a portion for forming the trough of a first thread formed on the molded ceramic product. The trough of the first thread is higher than the crest of a second thread formed on a mating component to be engaged with the first thread. Subsequently, the molded ceramic is fired. The trough of the first thread formed on the molded ceramic product thus produced has a depth that allows the trough of the first thread to avoid interference with the crest of the second thread of the mating component.

Abstract: The present invention relates to an optical part holding member made of ceramic and a production method thereof, and provides an optical part holding member made of ceramic such that a sintered body after processes of degreasing and sintering has small dimensional changes over dimensions of a mold, and a production method thereof. An example includes a lens holder to hold an optical part, made of a silicon nitride ceramic base composite material produced through a process in which silicon and nitrogen are reacted to be nitrided and contains silicon carbide and an iron compound.

Abstract: A lens assembly has: optical members including lenses and spacing rings; and a ceramic lens frame into which the optical members are inserted. A solid lubricant is applied to at least one of a part of the inner peripheral surface of the ceramic lens frame, which part is to be in contact with at least the outer peripheral surfaces of the optical members, and the outer peripheral surfaces of the optical members. Subsequently, the lenses and spacing rings are alternately inserted into the ceramic lens frame and then pressed by a pressing ring.

Abstract: A lens assembly made of porous ceramic is provided with concave sections into which an adhesive for fixing lenses inserted into a lens frame is injected. Each of the concave sections has an outward opening and a spacing wall provided between a hollow part of the lens frame and the opening. The adhesive injected into the concave sections passes through multiple pores in the lens frame made of porous ceramic, and reaches the periphery of each of the lenses, thereby fixing the lenses to an inner wall of the hollow part of the lens frame.

Abstract: A lens assembly includes a barrel having an object-side opening and an image-forming-side opening. The barrel further has a positioning section that positions an image-forming-side surface of a lens by having line contact around an optical axis at a center. The positioning section is disposed at a position that is closer to an object side than the image-forming-side opening of the barrel is. The barrel also has an image-forming section that extends from the positioning section to a center of the optical axis along the image-forming-side surface of the lens and forms an edge of the image-forming-side opening of the barrel.

Abstract: The present invention relates to an optical part holding member made of ceramic and a production method thereof, and provides an effective permeability to prevent dew condensation. The optical part holding member is made of a silicon nitride ceramic base composite material to hold an optical part, which is produced through a process of nitriding in which silicon is caused to react with nitrogen. By using the silicon nitride ceramic base composite material containing silicon carbide and an iron compound, an airflow volume of 50 ml or more per minute is achieved in an effective airflow area of 1.5 cm2 when an air pressure is added with a pressure difference of 0.4 MPa between both surfaces of a sample of the silicon nitride ceramic base composite material having 1 mm thickness, and the optical part holding member having effective permeability to prevent dew condensation is obtained.

Abstract: The present invention relates to an optical part holding member made of ceramic and a production method thereof, and provides an effective permeability to prevent dew condensation. The optical part holding member is made of a silicon nitride ceramic base composite material to hold an optical part, which is produced through a process of nitriding in which silicon is caused to react with nitrogen. By using the silicon nitride ceramic base composite material containing silicon carbide and an iron compound, an airflow volume of 50 ml or more per minute is achieved in an effective airflow area of 1.5 cm2 when an air pressure is added with a pressure difference of 0.4 MPa between both surfaces of a sample of the silicon nitride ceramic base composite material having 1 mm thickness, and the optical part holding member having effective permeability to prevent dew condensation is obtained.

Abstract: The present invention relates to an optical part holding member made of ceramic and a production method thereof, and provides an optical part holding member made of ceramic such that a sintered body after processes of degreasing and sintering has small dimensional changes over dimensions of a mold, and a production method thereof. An example includes a lens holder to hold an optical part, made of a silicon nitride ceramic base composite material produced through a process in which silicon and nitrogen are reacted to be nitrided and contains silicon carbide and an iron compound.

Abstract: Ceramic is molded to produce a molded ceramic product, using a mold that has a portion for forming the trough of a first thread formed on the molded ceramic product. The trough of the first thread is higher than the crest of a second thread formed on a mating component to be engaged with the first thread. Subsequently, the molded ceramic is fired. The trough of the first thread formed on the molded ceramic product thus produced has a depth that allows the trough of the first thread to avoid interference with the crest of the second thread of the mating component.

Abstract: A lens assembly made of porous ceramic is provided with concave sections into which an adhesive for fixing lenses inserted into a lens frame is injected. Each of the concave sections has an outward opening and a spacing wall provided between a hollow part of the lens frame and the opening. The adhesive injected into the concave sections passes through multiple pores in the lens frame made of porous ceramic, and reaches the periphery of each of the lenses, thereby fixing the lenses to an inner wall of the hollow part of the lens frame.

Abstract: A lens frame is made of ceramic having a linear expansion coefficient that is about the same as the linear expansion coefficient (5 to 10×10?6) of glass lenses. Preferably, a pressing ring and spacing rings are also made of ceramic. A lens assembly produced by using the lens frame, the pressing ring and the spacing rings is installed in an automobile or the like.

Abstract: A lens assembly includes a barrel having an object-side opening and an image-forming-side opening. The barrel further has a positioning section that positions an image-forming-side surface of a lens by having line contact around an optical axis at a center. The positioning section is disposed at a position that is closer to an object side than the image-forming-side opening of the barrel is. The barrel also has an image-forming section that extends from the positioning section to a center of the optical axis along the image-forming-side surface of the lens and forms an edge of the image-forming-side opening of the barrel.

Abstract: A lens assembly has: optical members including lenses and spacing rings; and a ceramic lens frame into which the optical members are inserted. A solid lubricant is applied to at least one of a part of the inner peripheral surface of the ceramic lens frame, which part is to be in contact with at least the outer peripheral surfaces of the optical members, and the outer peripheral surfaces of the optical members. Subsequently, the lenses and spacing rings are alternately inserted into the ceramic lens frame and then pressed by a pressing ring.

Abstract: A cartridge including a cartridge case having a disc-shaped recording medium received therein so as to allow predetermined information signals to be recorded and reproduced, and a shutter and method for producing the shutter which is molded of a synthetic resin to slidably open and close an opening portion formed on the cartridge case so as to allow at least a part of the disc-shaped recording medium to be exposed to the outside. The shutter includes an upper main plate, a lower main plate and a coupling plate which connects the upper main plate to the lower main plate via the coupling plate in an integrally molded state while having a U-shaped cross-sectional contour to hold the cartridge case in a clamped state. A gate used for performing a molding operation is formed on the outer surface of the side plate, with the position of the gate being determined such that it always remains within an effective opening region corresponding to the opening portion.

Abstract: A cartridge including a cartridge case having a disc-shaped recording medium received therein so as to allow predetermined information signals to be recorded and reproduced, and a shutter molded of a synthetic resin to slidably open and close an opening portion formed on the cartridge case so as to allow at least a part of the disc-shaped recording medium to be exposed to the outside. In accordance with the present invention, the shutter is composed of an upper main plate, a lower main plate and a coupling plate which connects the upper main plate to the lower main plate via the coupling plate in an integrally molded state while having an U-shaped cross-sectional contour to hold the cartridge case in a clamped state. A gate used for performing a molding operation is formed on the outer surface of the side plate, with the position of the gate being determined such that it always remains within an effective opening region corresponding to the opening portion.