Abstract: A reusing method of an end mill involves machining a base material of an end mill in advance so as to have coaxiality equal accuracy to coaxiality for a cutting part, and when the cutting part is worn out, cutting off of the cutting part and machining a new cutting part on a shank part while a part of outer peripheral surface of the shank part is left as margin without cutting. The new cutting part has accuracy of coaxiality and an outer diameter identical to those of the cutting part.

Abstract: A reusing method of an end mill 1, in which an end mill (1) has a margin which is a part of a circle having a diameter identical to a diameter of a shank part (3), the margin being provided on an outer edge of a cutting part (2), a base material of the end mill (1) is machined in advance so as to have coaxiality having equal accuracy to coaxiality for the cutting part (2), the shank part (3) is an unmachined part left without cutting the base material, the margin is a part of an outer peripheral surface of the base material left without cutting the base material when the outer edge is formed by cutting the base material, and when the cutting part (2) is worn out, the cutting part (2) is cut off and a new cutting part 2 is machined on the shank part (3) while a part of outer peripheral surface of the shank part is left as the margin without cutting, the new cutting part 2 having accuracy of coaxiality and an outer diameter identical to those of the cutting part (2).

Abstract: An optical article includes: an optical substrate, and a functional layer laminated on the surface of the optical substrate, the functional layer having a thickness T ?m that satisfies the following condition: 6.5dn+4.0?T?100 wherein the thickness T is larger than 5 ?m, and dn is the refractive index difference at the boundary of the optical substrate and the functional layer and satisfies the following condition: 0.06?dn?0.4.

Abstract: An optical article includes: an optical substrate, and a functional layer laminated on the surface of the optical substrate, the functional layer having a thickness T ?m that satisfies the following condition: 6.5dn+4.0?T?100 wherein the thickness T is larger than 5 ?m, and dn is the refractive index difference at the boundary of the optical substrate and the functional layer and satisfies the following condition: 0.06?dn?0.

Abstract: An optical article includes: an optical substrate, and a functional layer laminated on the surface of the optical substrate, the functional layer having a thickness T ?m that satisfies the following condition: 6.5dn+4.0?T?100 wherein the thickness T is larger than 5 ?m, and dn is the refractive index difference at the boundary of the optical substrate and the functional layer and satisfies the following condition: 0.06?dn?0.4.

Abstract: An optical article includes: an optical base material; a primer layer formed on the optical base material; a binder layer; and a hardcoat layer formed on the primer layer via the binder layer, the primer layer having a thickness of at least 700 nm, the binder layer having a lower refractive index than the refractive index of the primer layer and the refractive index of the hardcoat layer, and the binder layer having a thickness of at least 35 nm.

Abstract: An optical article includes: an optical substrate, and a functional layer that is light-transmissive and is laminated to the surface of the optical substrate, the period Pk (nm?1) of reflectance of the functional layer in the k-space being not more than 3.66×10?5.

Abstract: A method of manufacturing a colored lens includes: applying a coating liquid for forming a dyeable hard coat layer over a lens substrate; firstly heating the lens substrate coated with the coating liquid after the coating step at a temperature of T1° C. for t1 hours; dyeing the heated lens substrate by dipping it in a dyeing liquid after the first heating step; and secondly heating the lens substrate which is dyed after the dyeing step at a temperature of T2° C. for t2 hours, wherein the following expression is satisfied when the product of the temperature T1 and the time t1 is a first management value Q1 and the product of the temperature T2 and the time t2 is a second management value Q2: 0.2<Q1/(Q1+Q2)?0.5.

Abstract: An optical article includes: an optical substrate, and a functional layer laminated on the surface of the optical substrate, the functional layer having a thickness T ?m that satisfies the following condition: 6.5dn+4.0?T?100 wherein the thickness T is larger than 5 ?m, and dn is the refractive index difference at the boundary of the optical substrate and the functional layer and satisfies the following condition: 0.06?dn?0.4.

Abstract: An optical article includes: an optical substrate, and a functional layer that is light-transmissive and is laminated to the surface of the optical substrate, the period Pk (nm?1) of reflectance of the functional layer in the k-space being not more than 3.66×10?5.

Abstract: A method of manufacturing a colored lens includes: applying a coating liquid for forming a dyeable hard coat layer over a lens substrate; firstly heating the lens substrate coated with the coating liquid after the coating step at a temperature of T1° C. for t1 hours; dyeing the heated lens substrate by dipping it in a dyeing liquid after the first heating step; and secondly heating the lens substrate which is dyed after the dyeing step at a temperature of T2° C. for t2 hours, wherein the following expression is satisfied when the product of the temperature T1 and the time t1 is a first management value Q1 and the product of the temperature T2 and the time t2 is a second management value Q2: 0.2<Q1/(Q1+Q2)?0.5.

Abstract: The present invention includes a plastic lens having a plastic lens base material, a primer layer formed on the plastic lens base material, and a hard coat layer formed on the primer layer, the hard coat layer being formed from a hard coat composition having (A) an inorganic fine particle having a particle diameter of 1 to 100 millimicrons, (B) an organic silicon compound expressed in terms of a specified Formula (1), (C) a multi-functional epoxy compound, and (D) a curing catalyst. Such a plastic lens is excellent in shock impact resistance by including the primer layer and also shows improvements in scratch resistance, water resistance, and permanence properties while keeping the coloring properties of the hard coat layer of a colorable type.