Abstract: An optical apparatus is configured to introduce light from an object to an image pickup element, and includes first, second, and third retardation plates, a polarizer, and a setter. The first retardation plate, the second retardation plate, and the polarizer are arranged in this order from a side of the object to a side of the image pickup element. The slow axis direction or the fast axis direction of the second retardation plate tilts to the slow axis direction or the fast axis direction of the first retardation plate. The setter sets the retardation of the second retardation plate according to the polarization component of the light from the object.

Abstract: An optical apparatus includes a first retardation plate giving a retardation between polarization components in slow and fast axis directions, a second retardation plate changing a relative retardation between polarization components in slow and fast axis directions, and a polarizer extracting a polarization component guided to the image pickup element. The first and second retardation plates, and the polarizer are disposed in order from an object side. The slow or fast axis direction of the first retardation plate is parallel to a polarization direction of the polarization component extracted by the polarizer. The slow or fast axis direction of the second retardation plate is inclined by 45 degrees with respect to the polarization direction. When a design wavelength is ?, a phase change amount being a difference between maximum and minimum values of the relative retardations is in a range from 2?/5 to 3?/5 both inclusive.

Abstract: The present invention provides a method for producing lithium carbonate, that can shorten the time required in the production of lithium carbonate and has excellent maintenance property and production efficiency without forming fixed matters that require complicated procedures to remove in a reaction apparatus.

Abstract: An optical apparatus is configured to introduce light from an object to an image pickup element, and includes first, second, and third retardation plates, a polarizer, and a setter. The first retardation plate, the second retardation plate, and the polarizer are arranged in this order from a side of the object to a side of the image pickup element. The slow axis direction or the fast axis direction of the second retardation plate tilts to the slow axis direction or the fast axis direction of the first retardation plate. The setter sets the retardation of the second retardation plate according to the polarization component of the light from the object.

Abstract: An optical apparatus includes a first retardation plate giving a retardation between polarization components in slow and fast axis directions, a second retardation plate changing a relative retardation between polarization components in slow and fast axis directions, and a polarizer extracting a polarization component guided to the image pickup element. The first and second retardation plates, and the polarizer are disposed in order from an object side. The slow or fast axis direction of the first retardation plate is parallel to a polarization direction of the polarization component extracted by the polarizer. The slow or fast axis direction of the second retardation plate is inclined by 45 degrees with respect to the polarization direction. When a design wavelength is ?, a phase change amount being a difference between maximum and minimum values of the relative retardations is in a range from 2?/5 to 3?/5 both inclusive.

Abstract: An anti-reflection film includes first through ninth layers. Regarding light having a wavelength of 550 nm, where the refractive indexes of the first through ninth layers are n1 through n9 respectively, the optical film thicknesses d1 through d9 (nm) respectively, and the maximum value of the difference in the refractive index between adjoining layers for layers 1 through 8 is ?n, the following conditions are satisfied. 1.60?n1?1.70, 15 nm?d1?140 nm, 2.00?n2?2.40, 20 nm?d2?120 nm, 1.60?n3?1.70, 11 nm?d3?70 nm, 2.00?n4?2.40, 20 nm?d4?165 nm, 1.60?n5?1.70, 15 nm?d5?45 nm, 2.00?n6?2.40, 90 nm?d6?175 nm, 1.60?n7?1.70, 50 nm?d7?110 nm, 2.00?n8?2.40, 20 nm?d8?50 nm, 1.20?n9?1.28, 140 nm?d9?160 nm, and 0.40??n?0.67.

Abstract: The present invention provides a method for producing lithium carbonate, that can shorten the time required in the production of lithium carbonate and has excellent maintenance property and production efficiency without forming fixed matters that require complicated procedures to remove in a reaction apparatus.

Abstract: The polarization acquisition apparatus is configured to allow an image capturing system including an interchangeable lens and an image capturing apparatus to perform image capturing using polarized light. The polarization acquisition apparatus includes a variable polarization axis element in which a direction of its polarization transmission axis is variable, a driver configured to operate the variable polarization axis element so as to change the direction of the polarization transmission axis, a first mount to which the image capturing apparatus is detachably attachable, and a second mount to which the interchangeable lens is detachably attachable. The driver is configured to operate the variable polarization axis element so as to change the direction of the polarization transmission axis to at least three directions when the image capturing is performed multiple times.

Abstract: An optical low-pass filter is arranged on an object side than an image sensor in an image pickup apparatus and has an unevenness shape. The conditions of 5.0 ?m??z?80.0 ?m and 1.0?Ps/<Pf>?20.0 are satisfied where ?z represents a distance between the optical low-pass filter and the image sensor, Ps represents a pixel pitch of the image sensor, and <Pf> represents an average pitch of the unevenness shape.

Abstract: An optical apparatus includes a first phase plate which gives a fixed relative phase difference by ?/2 between a polarization component in a slow axis direction and a polarization component in a fast axis direction, a second phase plate which gives a relative phase difference between a polarization component in a slow axis direction and a polarization component in a fast axis direction, a polarizer which extracts a polarization component to be guided to the image pickup element, and a setter which sets the relative phase difference of the second phase plate, the slow axis direction of the second phase plate is inclined with respect to each of the slow and fast axes directions of the first phase plate, and the setter sets the relative phase difference of the second phase plate depending on the polarization component of light.

Abstract: An optical element includes an antireflection film. The antireflection film includes an uppermost layer having a refractive index nd of 1.20 to 1.30, a high refractive index layer having a refractive index of 2.00 to 2.40, and at least one of an intermediate refractive index layer having a refractive index of 1.55 to 1.70 and a low refractive index layer having a refractive index of 1.40 to 1.52. The predetermined condition is satisfied.

Abstract: The absorptive wire-grid polarizer includes a periodic structure formed on a substrate surface of a dielectric substrate and constituted by a metal and one or more dielectric materials. The periodic structure has a one-dimensional grating structure in which, in a sectional plane orthogonal to a normal to the substrate surface, grating portions of a metal grating formed of the metal and grating portions of dielectric gratings formed of the one or more dielectric materials are one-dimensionally arranged with a grating period P. The Conditions of nm?1.0, km?2.0, 0.01?FF?0.25, Nb?1.40, and h?250 [nm] are satisfied where h represents an entire height of the metal and dielectric gratings, nm represents a refractive index of a real part of a complex refractive index of the metal, km represents an extinction coefficient of an imaginary part of the complex refractive index, and nb represents an average refractive index of the dielectric grating.

Abstract: A projection display apparatus includes a polarization beam splitter, a first phase compensation plate including two layers, and a light modulator. Each layer has a constant axial angle, and an optical axis of each layer inclines with respect to the x axis in an xz plane. The axial angle of the layer closer to the polarization beam splitter among the two layers is larger than the axial angle of the layer farther from the polarization beam splitter. 20°??max??min?80° is satisfied where ?max is a maximum value of the axial angle and ?min is a minimum value of the axial angle. 40°??ave?70° is satisfied where ?ave is an average value of axial angles of the two layers.

Abstract: An image display apparatus includes an image display element configured to modulate incident light from a light source, a polarization splitting element that has characteristics of transmitting first polarized light and reflecting second polarized light different from the first polarized light and that is configured to synthesize image light from the image display element to be introduced into a projection optical system, and a phase difference plate that is disposed at a side of the projection optical system relative to the polarization splitting element. The phase difference plate has an optic axis in a direction different from a surface normal direction and an in-plane direction of the phase difference plate.

Abstract: An optical element includes an antireflection film. The antireflection film includes an uppermost layer having a refractive index nd of 1.20 to 1.30, a high refractive index layer having a refractive index of 2.00 to 2.40, and at least one of an intermediate refractive index layer having a refractive index of 1.55 to 1.70 and a low refractive index layer having a refractive index of 1.40 to 1.52. The predetermined condition is satisfied.

Abstract: A polarizer includes a first medium disposed at an emission side, a second medium disposed at an incident side, and a plurality of laminated structures provided at a predetermined grating period in a grating period direction, the laminated structure includes, in order from the first medium to the second medium, a first dielectric layer, a metallic layer, and a second dielectric layer between the first medium and the second medium, the polarizer is configured to reflect polarized light oscillating in a direction orthogonal to the grating period direction in a particular wavelength band and to transmit light other than the polarized light, and predetermined expressions are satisfied.

Abstract: A projection-type image display apparatus includes a color separation element including a color separation surface, a light modulation element configured to receive the light divided by the color separation element, a polarizing beam splitter disposed between the color separation element and a projection optical system to separate a light path of a light modulated by the light modulation element according to a polarization direction and guide the resulting light to the projection optical system, and a phase difference plate disposed between the color separation element and the light modulation element. An optic axis of the phase difference plate and the normal of the color separation surface are substantially parallel or perpendicular to each other, in a cross section parallel to a normal of the color separation surface and a normal of the light modulation element.

Abstract: An anti-reflection film includes first through ninth layers. Regarding light having a wavelength of 550 nm, where the refractive indexes of the first through ninth layers are n1 through n9 respectively, the optical film thicknesses d1 through d9 (nm) respectively, and the maximum value of the difference in the refractive index between adjoining layers for layers 1 through 8 is ?n, the following conditions are satisfied. 1.60?n1?1.70, 15 nm?d1?140 nm, 2.00?n2?2.40, 20 nm?d2?120 nm, 1.60?n3?1.70, 11 nm?d3?70 nm, 2.00?n4?2.40, 20 nm?d4?165 nm, 1.60?n5?1.70, 15 nm?d5?45 nm, 2.00?n6?2.40, 90 nm?d6?175 nm, 1.60?n7?1.70, 50 nm?d7?110 nm, 2.00?n8?2.40, 20 nm?d8?50 nm, 1.20?n9?1.28, 140 nm?d9?160 nm, and 0.40??n?0.67.

Abstract: The present invention relates to a method for producing lithium carbonate, the method including: mixing ammonia and carbon dioxide gas (carbonate gas) with an aqueous solution containing lithium chloride to conduct a carbonation reaction; and thereafter, recovering a produced solid by solid-liquid separation, and also relates to a method for producing high purity lithium carbonate.

Abstract: The absorptive wire-grid polarizer includes a periodic structure formed on a substrate surface of a dielectric substrate and constituted by a metal and one or more dielectric materials. The periodic structure has a one-dimensional grating structure in which, in a sectional plane orthogonal to a normal to the substrate surface, grating portions of a metal grating formed of the metal and grating portions of dielectric gratings formed of the one or more dielectric materials are one-dimensionally arranged with a grating period P. The Conditions of nm?1.0, km?2.0, 0.01?FF?0.25, Nb?1.40, and h?250 [nm] are satisfied where h represents an entire height of the metal and dielectric gratings, nm represents a refractive index of a real part of a complex refractive index of the metal, km represents an extinction coefficient of an imaginary part of the complex refractive index, and nb represents an average refractive index of the dielectric grating.