Abstract: Provided is an optical system including, in order from an object side to an image side, a front lens unit, an aperture stop, and a rear lens unit. The front lens unit consists of a positive lens and a diffractive optical element, which are arranged in order from the object side to the image side. The diffractive optical element consists of a plurality of lenses that are cemented to each other, and at least one of cemented surfaces of the plurality of lenses is a diffractive surface. An interval on an optical axis between the positive lens and the diffractive optical element is the largest among intervals on the optical axis between two lenses that are adjacent in the optical system.

Abstract: Provided is an optical system including a front unit, an aperture stop and a rear unit which are arranged in order from an object side to an image side. The front unit includes a diffractive optical element, at least one first refractive optical element having a power in the same sign as a sign of a power at a diffractive surface of the diffractive optical element, and at least one second refractive optical element having a power in a different sign from the sign of the power at the diffractive surface. A partial dispersion ratio between a d-line and a C-line and a partial dispersion ratio between a g-line and the d-line of the at least one first refractive optical element and the at least one second refractive optical element are appropriately set.

Abstract: Provided is an optical system including, in order from an object side to an image side, a front lens unit, an aperture stop, and a rear lens unit. The front lens unit consists of a positive lens and a diffractive optical element, which are arranged in order from the object side to the image side. The diffractive optical element consists of a plurality of lenses that are cemented to each other, and at least one of cemented surfaces of the plurality of lenses is a diffractive surface. An interval on an optical axis between the positive lens and the diffractive optical element is the largest among intervals on the optical axis between two lenses that are adjacent in the optical system.

Abstract: An optical system includes a diffractive surface and at least one aspherical surface, an aspherical surface of at least one aspherical surface closest to the diffractive surface is referred to as a first aspherical surface, a phase function ?(r) and an aspherical function X(r) of the first aspherical surface increase with different signs from each other in a height direction with increasing a distance from an optical axis, and a condition below is satisfied: - 0.10 ? ? i = 1 p ? ( Ci ? ( f / Fno ) 2 ? i - 1 ) / ? j = 1 q ? ( Aj ? ( f / Fno ) 2 ? j + 1 ) ? - 0.01 where f is a focal length of the optical system when focusing on an infinite object, and Fno is an F number of the optical system.

Abstract: Provided is an optical system including a front unit, an aperture stop and a rear unit which are arranged in order from an object side to an image side. The front unit includes a diffractive optical element, at least one first refractive optical element having a power in the same sign as a sign of a power at a diffractive surface of the diffractive optical element, and at least one second refractive optical element having a power in a different sign from the sign of the power at the diffractive surface. A partial dispersion ratio between a d-line and a C-line and a partial dispersion ratio between a g-line and the d-line of the at least one first refractive optical element and the at least one second refractive optical element are appropriately set.

Abstract: An optical system includes a diffractive surface and at least one aspherical surface, an aspherical surface of at least one aspherical surface closest to the diffractive surface is referred to as a first aspherical surface, a phase function ?(r) and an aspherical function X(r) of the first aspherical surface increase with different signs from each other in a height direction with increasing a distance from an optical axis, and a condition below is satisfied: - 0.10 ? ? i = 1 p ? ( Ci ? ( f / Fno ) 2 ? i - 1 ) / ? j = 1 q ? ( Aj ? ( f / Fno ) 2 ? j + 1 ) ? - 0.01 where f is a focal length of the optical system when focusing on an infinite object, and Fno is an F number of the optical system.

Abstract: It is an object of the present invention to provide adhesive compositions having excellent flexibility, rubber elasticity, mechanical properties, heat resistance and low-temperature properties. An adhesive composition of the invention includes 10 to 70 parts by weight of a soft polypropylene resin composition (X) which includes 40 to 98 wt % of a propylene copolymer (A) satisfying the following requirements (A1) to (A8) and 2 to 60 wt % of a crystalline isotactic polypropylene (B) satisfying the following requirements (B1) to (B3), and 30 to 90 parts by weight of a tackifier (C) (wherein the total of the component (X) and the component (C) is 100 parts by weight), wherein (A1) Shore A hardness: 20 to 90; (A2) the copolymer comprises a copolymer with C3 units at 51 to 90 mol %, C2 units at 7 to 24 mol % and C4-20 ?-olefin units at 3 to 25 mol %; (A3) Mw/Mn: 1.2 to 3.5; (A4) mm: 85 to 99.9%; (A5) value B: 0.8 to 1.3; (A6) 2,1-insertion ratio: less than 1%; (A7) Tg: ?10° C. to ?50° C.; (A8) MFR (230° C.): 0.

Abstract: The optical system includes, in order from an object side, a front lens unit LF, an aperture stop S, a rear lens unit LR. The front lens unit includes a diffraction optical element Ldoe. A stop side positive lens Lsp disposed closest to the aperture stop among the rear lens unit satisfies 1.55?Ndsp?1.70, 30.0??dsp?50.0, and 5.0×10?4???dCsp?5.0×10?3. Ndsp and ?dsp repectively represent a refractive index and an Abbe number of the stop side positive lens for a d-line, and ??dCsp is represents a value defined by ??dCsp=?dCsp?(?0.17041×?gdsp+0.513577) where Ngsp, NCsp and NFsp respectively represent refractive indices of the stop side positive lens for a g-line, a C-line and an F-line. ?dCsp and ?gdsp are respectively defined by ?dCsp=(Ndsp?NCsp)/(NFsp?NCsp) and ?gdsp=(Ngsp?Ndsp)/(NFsp?NCsp).

Abstract: The optical system includes, in order from an object side, a front lens unit LF, an aperture stop S, a rear lens unit LR. The front lens unit includes a diffraction optical element Ldoe. A stop side positive lens Lsp disposed closest to the aperture stop among the rear lens unit satisfies 1.55?Ndsp?1.70, 30.0??dsp?50.0, and 5.0×10?4???dCsp?5.0×10?3. Ndsp and ?dsp repectively represent a refractive index and an Abbe number of the stop side positive lens for a d-line, and ??dCsp is represents a value defined by ??dCsp=?dCsp?(?0.17041×?gdsp+0.513577) where Ngsp, NCsp and NFsp respectively represent refractive indices of the stop side positive lens for a g-line, a C-line and an F-line. ?dCsp and ?gdsp are respectively defined by ?dCsp=(Ndsp?NCsp)/(NFsp?NCsp) and ?gdsp=(Ngsp?Ndsp)/(NFsp?NCsp).

Abstract: Provided is an adhesive resin composition having improved heat resistance without deteriorations in adhesive strength and flexibility. The adhesive resin composition comprises 30 to 98 wt % of an ethylene/vinyl acetate copolymer (a) and 70 to 2 wt % of a propylene resin composition (P), wherein the total of the component (a) and the component (P) is 100 wt %. The propylene resin composition (P) comprises 60 to 0 wt % of a propylene polymer (b) having a melting point of 120 to 170° C. and a melt flow rate of 0.1 to 500 g/10 min, and 40 to 100 wt % of a propylene polymer (c) having a melting point of less than 120° C. or showing no melting points and having a melt flow rate of 0.1 to 500 g/10 min, wherein the total of the component (b) and the component (c) is 100 wt %.

Abstract: The optical system includes plural lens groups, a negative lens included in one lens group among the plural lens groups and formed of a first medium, a diffractive grating formed on at least one lens surface of the negative lens and being in contact with a second medium different from the first medium, and a positive lens included in the one lens group and formed of a third medium different from the first medium and the second medium. The first medium satisfies ndA?1.7 and 40??dA?55 where ndA represents a refractive index of the first medium for a d-line, and ?dA represents an Abbe number of the first medium for the d-line. The third medium satisfies ndC?1.55 and ?dC?60 where ndC represents a refractive index of the third medium for the d-line, and ?dC represents an Abbe number of the third medium for the d-line.

Abstract: Object: To provide adhesive resin compositions improved in heat resistance without deteriorations in adhesive strength and flexibility. Solution: An adhesive resin composition comprises 30 to 98 wt % of an ethylene/vinyl acetate copolymer (a) and 70 to 2 wt % of a propylene resin composition (P) described below (wherein the total of the component (a) and the component (P) is 100 wt %). The propylene resin composition (P) comprises 60 to 0 wt % of a propylene polymer (b) having a melting point of 120 to 170° C. and a melt flow rate of 0.1 to 500 g/10 min, and 40 to 100 wt % of a propylene polymer (c) having a melting point of less than 120° C. or showing no melting points and having a melt flow rate of 0.1 to 500 g/10 min (wherein the total of the component (b) and the component (c) is 100 wt %).

Abstract: There is provided a thermoplastic polymer composition excellent in the balance among mechanical strength, elongation at break, flexibility and heat resistance, and an article including the composition, and an electric wire and electric cable having an insulator and/or a sheath including the composition. The thermoplastic polymer composition includes 1 to 350 parts by mass of a filler (D) with respect to 100 parts by mass of polymer components that comprise 50 to 90% by mass of an ethylene/unsaturated ester copolymer (A); 1 to 40% by mass of a propylene-based polymer (B) having a melting point as measured by differential scanning calorimetry (DSC) of from 120 to 170° C.; and 1 to 49% by mass of a propylene-based polymer (C) having a melting point as measured by differential scanning calorimetry (DSC) of lower than 120° C. or not being observed, provided that the total amount of (A), (B) and (C) is 100% by mass.

Abstract: Provided are an optical element in which a thickness of a refractive optical portion having an extraordinary partial dispersion characteristic is suitably specified to minimize flare generated by a diffraction optical portion, to thereby sufficiently correct chromatic aberrations to obtain excellent optical performance, and an optical system including the optical element. The optical system includes a cemented portion in which the refractive optical portion made of a solid material and has a refractive action is brought into intimate contact with at least one of light incident and exiting surfaces of the diffraction optical portion having a plurality of diffraction gratings which are layered. An Abbe (?d), a partial dispersion ratio (?gF), and an extraordinary partial dispersion ratio (??gF) of the solid material are suitably set.

Abstract: The optical system includes plural lens groups, a negative lens included in one lens group among the plural lens groups and formed of a first medium, a diffractive grating formed on at least one lens surface of the negative lens and being in contact with a second medium different from the first medium, and a positive lens included in the one lens group and formed of a third medium different from the first medium and the second medium. The first medium satisfies ndA?1.7 and 40??dA?55 where ndA represents a refractive index of the first medium for a d-line, and ?dA represents an Abbe number of the first medium for the d-line. The third medium satisfies ndC?1.55 and ?dC?60 where ndC represents a refractive index of the third medium for the d-line, and ?dC represents an Abbe number of the third medium for the d-line.

Abstract: An optical system includes a front lens group, a stop, and a rear lens group arranged successively in order from the object side toward the image side. The front lens group includes a solid material element having a refractive action. The rear lens group includes a diffractive optical element. The solid material element is formed on at least one transmissive surface of a refractive optical element. An Abbe number of a solid material of the solid material element with respect to the d line, a partial dispersion ratio of the solid material with respect to the g line and the F line, respective thicknesses of the solid material element and the refractive optical element when measured on the optical axis, and respective focal lengths of the diffractive optical portion of the diffractive optical element and the solid material element in air satisfy predetermined conditional expressions.

Abstract: It is an object of the present invention to provide adhesive compositions having excellent flexibility, rubber elasticity, mechanical properties, heat resistance and low-temperature properties. An adhesive composition of the invention includes 10 to 70 parts by weight of a soft polypropylene resin composition (X) which includes 40 to 98 wt % of a propylene copolymer (A) satisfying the following requirements (A1) to (A8) and 2 to 60 wt % of a crystalline isotactic polypropylene (B) satisfying the following requirements (B1) to (B3), and 30 to 90 parts by weight of a tackifier (C) (wherein the total of the component (X) and the component (C) is 100 parts by weight), wherein (A1) Shore A hardness: 20 to 90; (A2) the copolymer comprises a copolymer with C3 units at 51 to 90 mol %, C2 units at 7 to 24 mol % and C4-20 ?-olefin units at 3 to 25 mol %; (A3) Mw/Mn: 1.2 to 3.5; (A4) mm: 85 to 99.9%; (A5) value B: 0.8 to 1.3; (A6) 2,1-insertion ratio: less than 1%; (A7) Tg: ?10° C. to ?50° C.; (A8) MFR (230° C.): 0.

Abstract: Provided are an optical element in which a thickness of a refractive optical portion having an extraordinary partial dispersion characteristic is suitably specified to minimize flare generated by a diffraction optical portion, to thereby sufficiently correct chromatic aberrations to obtain excellent optical performance, and an optical system including the optical element. The optical system includes a cemented portion in which the refractive optical portion made of a solid material and has a refractive action is brought into intimate contact with at least one of light incident and exiting surfaces of the diffraction optical portion having a plurality of diffraction gratings which are layered. An Abbe (?d), a partial dispersion ratio (?gF), and an extraordinary partial dispersion ratio (??gF) of the solid material are suitably set.

Abstract: The diffractive optical element includes two diffraction gratings made of different materials and being in contact with each other at their grating surfaces. The materials satisfy the following conditions, and the second material is obtained by mixing a resin material with a particulate material satisfying the following conditions: nd1?1.48, ?d1?40, (?1.665E?07×?d13+5.213E?05×?d12?5.656E?03×?d1+0.675)??g,F1?(?1.665E?07×?d13+5.213E?05×?d12?5.656E?03×?d1+0.825), (?1.687E?07×?d13+5.702E?05×?d12?6.603E?03×?d1+1.400)??g,d1?(?1.687E?07×?d13+5.702E?05×?d12?6.603E?03×?d1+1.580), nd2?1.6, ?d2?30, ?g,F2?(?1.665E?07×?d23+5.213E?05×?d22?5.656E?03×?d2+0.675), ?g,d2?(?1.687E?07×?d23+5.702E?05×?d22?6.603E?03×?d2+1.400), nd1?nd2>0, ndb2?1.70, ?db2?20. The element achieves a high diffraction efficiency in a specific diffraction order over a wide wavelength range.

Abstract: An optical system includes a front lens group, a stop, and a rear lens group arranged successively in order from the object side toward the image side. The front lens group includes a solid material element having a refractive action. The rear lens group includes a diffractive optical element. The solid material element is formed on at least one transmissive surface of a refractive optical element. An Abbe number of a solid material of the solid material element with respect to the d line, a partial dispersion ratio of the solid material with respect to the g line and the F line, respective thicknesses of the solid material element and the refractive optical element when measured on the optical axis, and respective focal lengths of the diffractive optical portion of the diffractive optical element and the solid material element in air satisfy predetermined conditional expressions.