Optical element, method for producing the same, and display apparatus
An optical element having an anti-reflection function includes a base having a main surface, and a plurality of projecting or recessed structures arranged on the main surface of the base at a fine pitch equal to or less than the wavelength of visible light, wherein the main surface of the base, the main surface having the structures thereon, has hydrophilicity, and a contact angle of the main surface of the base, the main surface having the structures thereon, to pure water is 30° or less.
1. An optical element having an anti-reflection function, comprising:
a base having a main surface; and
a plurality of projecting or recessed structures arranged on the main surface of the base at a fine pitch equal to or less than the wavelength of visible light,
wherein the main surface of the base, the main surface having the structures thereon, has hydrophilicity,
a contact angle of the main surface of the base, the main surface having the structures thereon, to pure water is 30° or less, and
a contact angle of the main surface of the base, the main surface having the structures thereon, to oleic acid is 30° or less.
2. The optical element according to claim 1 ,
wherein the contact angle of the main surface of the base, the main surface having the structures thereon, to pure water is 10.6° or more and 30° or less.
3. The optical element according to claim 1 ,
the contact angle of the main surface of the base, the main surface having the structures thereon, to oleic acid is 5° or more and 30° or less.
4. The optical element according to claim 1 ,
the contact angle of the main surface of the base, the main surface having the structures thereon, to pure water is 10.6° or more and 30° or less, and
the contact angle of the main surface of the base, the main surface having the structures thereon, to oleic acid is 5° or more and 30° or less.
5. The optical element according to claim 1 ,
wherein the structures each have an elliptical cone shape or a truncated elliptical cone shape, the major axis direction of which is a direction in which the tracks extend.
6. The optical element according to claim 1 ,
wherein the structures are arranged so as to form a plurality of rows of tracks on the main surface of the base and form a hexagonal lattice pattern, a quasi-hexagonal lattice pattern, a tetragonal lattice pattern, or a quasi-tetragonal lattice pattern.
7. The optical element according to claim 1 , wherein a filling factor of the structures to the main surface of the base is 65% or more.
8. The optical element according to claim 6 ,
wherein the structures are arranged so as to form a plurality of rows of linear tracks and form a quasi-hexagonal lattice pattern, and
an average difference between a maximum height and a minimum depth between adjacent structures in the direction in which the tracks extend is smaller than an average difference between a maximum height and a minimum depth between adjacent structures in a row direction of the tracks.
9. The optical element according to claim 6 ,
wherein the structures are arranged so as to form a plurality of rows of linear tracks and form a tetragonal lattice pattern or a quasi-tetragonal lattice pattern, and
an average difference between a maximum height and a minimum depth between adjacent structures in an arrangement direction that is slanted with respect to the direction in which the tracks extend is smaller than an average difference between a maximum height and a minimum depth between adjacent structures in the direction in which the tracks extend.
10. The optical element according to claim 6 , wherein an arrangement pitch P 1 of the structures in the same track is longer than an arrangement pitch P 2 of the structures between two adjacent tracks.
11. The optical element according to claim 6 ,
wherein the structures form a hexagonal lattice pattern or a quasi-hexagonal lattice pattern on the main surface of the base, and
when an arrangement pitch of the structures in the same track is represented by P 1 and an arrangement pitch of the structures between two adjacent tracks is represented by P 2 , the ratio P 1 /P 2 satisfies the relationship 1.00≦P 1 /P 2 ≦1.1 or 1.00<P 1 /P 2 ≦1.1.
12. The optical element according to claim 6 ,
wherein the structures form a tetragonal lattice pattern or a quasi-tetragonal lattice pattern on the main surface of the base, and
when an arrangement pitch of the structures in the same track is represented by P 1 and an arrangement pitch of the structures between two adjacent tracks is represented by P 2 , the ratio P 1 /P 2 satisfies the relationship 1.4<P 1 /P 2 ≦1.5.
13. A display apparatus comprising:
an optical element having an anti-reflection function, comprising:
a base having a main surface; and
a plurality of projecting or recessed structures arranged on the main surface of the base at a fine pitch equal to or less than the wavelength of visible light,
wherein the main surface of the base, the main surface having the structures thereon, has hydrophilicity,
a contact angle of the main surface of the base, the main surface having the structures thereon, to pure water is 30° or less, and
a contact angle of the main surface of the base, the main surface having the structures thereon, to oleic acid is 30° or less.
14. A method for producing an optical element having an anti-reflection function, the method comprising:
forming a plurality of projecting or recessed structures arranged on a main surface of a base at a fine pitch equal to or less than the wavelength of visible light by transferring recesses and projections formed on a surface of a master to a transfer material; and
wherein the main surface of the base, the main surface having the structures thereon, has hydrophilicity,
a contact angle of the main surface of the base, the main surface having the structures thereon, to pure water is 30° or less, and
a contact angle of the main surface of the base, the main surface having the structures thereon, to oleic acid is 30° or less.