Abstract: An optical element includes a separation section that can separate incident light according to a wavelength. The separation section has an optical characteristic in which incident light in a first wavelength band is reflected, incident light in a second wavelength band is transmitted, and incident light in a third wavelength band is partially transmitted and partially reflected.

Abstract: A film of aluminum 2 is formed on a glass substrate (BK7) 1 by vacuum evaporation, and a multilayer optical thin film 3 is formed by an ion sputtering method on this aluminum film 2. Afterwards, such a member is cut into small pieces by means of dicing, and the aluminum 2 is then etched by a sodium hydroxide solution, so that the glass substrate 1 and the multilayer optical thin film 3 are separated. When the aluminum thickness exceeds 90 nm, clouding occurs in the multilayer optical thin film 3, and when the aluminum thickness is less than 10 nm, the separation of the glass substrate and multilayer optical thin film cannot be performed cleanly. Accordingly, the aluminum thickness is set in a range of 10 to 90 nm.

Abstract: A multilayer optical thin film 4 is formed on the surface of a substrate 1 made of quartz having a thickness of 0.8 mm or less by alternately laminating SiO2 thin films 2 and Nb2O5 thin films 3 for a total of approximately 100 layers. The linear expansion coefficient of the substrate 1 is small, and the difference from that of the multilayer optical thin film 4 is large. Therefore, when the substrate 1 is lowered to ordinary temperature from the film formation state that is normally at approximately 200° C., the compressive stress of the multilayer optical thin film 4 and the thermal stress that is generated as a result of the temperature drop cancel each other out, so that deformation (warpage) of the substrate 1 is alleviated. Accordingly, when the substrate 1 is cut by a dicing saw or the like, working is easy, there is little damage, and the surface precision of the cut-out optical elements is improved.

Abstract: A film of aluminum 2 is formed on a glass substrate (BK7) 1 by vacuum evaporation, and a multilayer optical thin film 3 is formed by an ion sputtering method on this aluminum film 2. Afterwards, such a member is cut into small pieces by means of dicing, and the aluminum 2 is then etched by a sodium hydroxide solution, so that the glass substrate 1 and the multilayer optical thin film 3 are separated. When the aluminum thickness exceeds 90 nm, clouding occurs in the multilayer optical thin film 3, and when the aluminum thickness is less than 10 nm, the separation of the glass substrate and multilayer optical thin film cannot be performed cleanly. Accordingly, the aluminum thickness is set in a range of 10 to 90 nm.

Abstract: A film of aluminum 2 is formed on a glass substrate (BK7) 1 by vacuum evaporation, and a multilayer optical thin film 3 is formed by an ion sputtering method on this aluminum film 2. Afterwards, such a member is cut into small pieces by means of dicing, and the aluminum 2 is then etched by a sodium hydroxide solution, so that the glass substrate 1 and the multilayer optical thin film 3 are separated. When the aluminum thickness exceeds 90 nm, clouding occurs in the multilayer optical thin film 3, and when the aluminum thickness is less than 10 nm, the separation of the glass substrate and multilayer optical thin film cannot be performed cleanly. Accordingly, the aluminum thickness is set in a range of 10 to 90 nm.

Abstract: The present invention relates to optical apparatus provided with an optical element for outputting polarized light beams separated generally in parallel. The optical apparatus according to this invention comprises an optical element having a pair of optical members being prisms cross sections of which are right-angled triangles similar to each other, each having a vertex angle of less than 45 degrees, and being constructed in a unitary double prism structure in which the optical members are cemented to each other between side faces thereof, each side face being between the right angle and the vertex angle of less than 45 degrees out of two orthogonal side faces of each optical member, and a polarization splitting portion comprising an optical thin film group formed on the cemented faces of the double prism structure to polarization-split light incident thereto.

Abstract: The invention provides an electrostatic copier having a smoothing member at an upstream side in the developer conveying direction in the vicinity of a developing area between a developer conveyer and an image-forming member in order to smooth a developer layer on the conveyor prior to transfer of the image forming member. Further, one surface of the smoothing member is so arranged as to come in contact with the image-forming member and another surface smoothes the developer layer. The developer conveyer has a magnet member therein and the magnet member is positioned to face the smoothing portion of the smoothing member.