Abstract: A carbon material for a non-aqueous secondary battery containing a graphite capable of occluding and releasing lithium ions, and having a cumulative pore volume at pore diameters in a range of 0.01 ?m to 1 ?m of 0.08 mL/g or more, a roundness, as determined by flow-type particle image analysis, of 0.88 or greater, and a pore diameter to particle diameter ratio (PD/d50 (%)) of 1.8 or less, the ratio being given by equation (1A): PD/d50 (%)=mode pore diameter (PD) in a pore diameter range of 0.01 ?m to 1 ?m in a pore distribution determined by mercury intrusion/volume-based average particle diameter (d50)×100 is provided.

Abstract: An imaging lens includes, in order from an object side to an image side, a first lens including a negative meniscus lens having a convex shape facing the object, a second lens including a positive meniscus lens having a convex shape facing the image, at least one lens including a third lens, a fourth lens, a fifth lens, and a sixth lens including a positive lens having a convex image side surface, and Expression (1) is satisfied as follows. Further, an imaging apparatus including the imaging lens is provided. 1.2<D2/f??(1) where D2 is a thickness of the second lens on the optical axis, and f is a focal length of the imaging lens.

Abstract: A condensing objective optical system includes a first lens group having negative refractive power, a second lens group being a focus group having positive refractive power, and a photoacoustic element disposed closest to an object in this order. The photoacoustic element reflects an optical wave from the second lens group toward an object to transmit a photoacoustic wave from the object side. The condensing objective optical system satisfies a specific conditional expression that defines the conditions of the included lens and the condition regarding focusing.

Abstract: A correction lens is used in an optical system in which a light-transmissive cover member having radii of curvature different from each other in a predetermined first direction and a second direction perpendicular to the first direction is disposed on an object side. Radii of curvature of an image-side surface of the correction lens are different in the first direction and the second direction, and satisfy a predetermined condition.

Abstract: A correction lens is used in an optical system in which a light-transmissive cover member having radii of curvature different from each other in a predetermined first direction and a second direction perpendicular to the first direction is disposed on an object side. Radii of curvature of an image-side surface of the correction lens are different in the first direction and the second direction, and satisfy a predetermined condition.

Abstract: An object of the present invention is to provide an optical system for an infrared ray which can provide a bright image, and can be applied to fixed focal length lenses among wide-angle to medium-telephoto. To achieve the object, the optical system for an infrared ray is constituted by a first lens having negative refractive power and a second lens having positive refractive power, these are arranged sequentially from an object side, wherein both the first lens and the second lens are made of an infrared transmitting material that transmits a light beam in an infrared wavelength range of 3 micron-meters or more to 14 micron-meters or less, and at least one of the lenses is made of an infrared transmitting material excluding germanium.

Abstract: The invention provides an infrared fixed-focus lens of which component lens pieces are made of germanium characterized by low chromatic dispersion, and have no surface processed to serve as diffraction optics. The infrared fixed-focus lens comprises a first lens piece disposed closer to an object and of negative power, and a second lens piece disposed closer to the image plane and of positive power. Both the first and second lens pieces are made of germanium.

Abstract: An object of the present invention is to provide an optical system for an infrared ray which can provide a bright image, and can be applied to fixed focal length lenses among wide-angle to medium-telephoto. To achieve the object, the optical system for an infrared ray is constituted by a first lens having negative refractive power and a second lens having positive refractive power, these are arranged sequentially from an object side, wherein both the first lens and the second lens are made of an infrared transmitting material that transmits a light beam in an infrared wavelength range of 3 micron-meters or more to 14 micron-meters or less, and at least one of the lenses is made of an infrared transmitting material excluding germanium.