JP2000098118A5 - - Google Patents

Description

0013
[Means for solving problems]
The diffractive optical element of the invention of claim 1 is a diffractive optical element in which a plurality of diffraction gratings having different Abbe numbers are laminated, and at least one diffraction grating uses a plastic material or an ultraviolet curable resin having an Abbe number of 25 or less. The other at least one diffraction grating is characterized in that a material having an Abbe number of 40 or more is used.

0014.
The diffractive optical element of the invention of claim 2 is a diffractive optical element in which the diffraction efficiency of diffracted light of a specific order is increased over the entire wavelength region of use by having a lattice structure in which a plurality of diffraction gratings having different abbe numbers are laminated. together in at least one of the diffraction gratings using the Abbe number 25 less plastic material or an ultraviolet curable resin is characterized in Rukoto using an Abbe number of 40 or more materials to another of the at least one diffraction grating.

0015.
The diffractive optical element of the invention of claim 3 is a diffractive optical element in which a plurality of diffraction gratings having different numbers of abbets are laminated, and each of the plurality of diffraction gratings has a lattice thickness of 10 μm or less, and at least one diffraction grating is used. It is characterized in that a plastic material having an abbe number of 25 or less or an ultraviolet curable resin is used, and a material having an abbe number of 40 or more is used for at least one other diffraction grating.

0016.
The diffraction optical element of the invention of claim 4 is a diffraction optical element in which the diffraction efficiency of diffracted light of a specific order is increased over the entire wavelength region of use by having a lattice structure in which a plurality of diffraction gratings having different abbe numbers are laminated. The lattice thickness of each of the plurality of diffraction gratings is 10 μm or less, and a plastic material or an ultraviolet curable resin having an Abbe number of 25 or less is used for at least one diffraction grating, and an Abbe number of 40 or more is used for the other at least one diffraction grating. It is characterized by using the material of.

[0017]
The invention of claim 5 is characterized in that, in the invention of claim 1, 2, 3 or 4, the lattice thickness of each of the plurality of diffraction gratings is 7.5 μm or less.

0018
In the invention of claim 6, the diffraction grating using the material having an Abbe number of 25 or less in the invention of any one of claims 1 to 5 is a diffraction grating using the material having an Abbe number of 40 or more via an air layer. It is characterized by being laminated with.

0019
The invention of claim 7 sets d / P <1/6 when each of the plurality of diffraction gratings has a lattice pitch of P and a lattice thickness of d in the invention of any one of claims 1 to 6. It is characterized by satisfying.

0020
The invention of claim 8 is characterized in that, in the invention of any one of claims 1 to 7, each of the plurality of diffraction gratings satisfies 1 <d <6 when the lattice thickness is d (μm). It is supposed to be.

0021.
The invention of claim 9 is characterized in that the wavelength region used in the invention of any one of claims 1 to 8 is a visible region.

0022.
The invention of claim 10 is the invention of any one of claims 1 to 9, wherein the plurality of diffraction gratings are formed on a transparent substrate, and are closest to the transparent substrate among the plurality of diffraction gratings. The diffraction grating is characterized in that it is made of the same material as the transparent substrate.

[0023]
The invention of claim 11 is characterized in that, in the invention of any one of claims 1 to 10, the diffraction efficiency is designed to be 97% or more over the entire wavelength region used.

0024
The invention of claim 12 is characterized in that the invention of any one of claims 1 to 10 is designed so that the diffraction efficiency of each of the d-line, F-line, and C-line is 99% or more. ..

0025
The optical system of the invention of claim 13 is characterized by having the diffractive optical element according to any one of claims 1 to 12 and a lens.

0026
The imaging optical system of the invention of claim 14 is characterized by having the diffractive optical element according to any one of claims 1 to 12 and a lens.

[0027]
The imaging optical system of the invention of claim 15 is characterized by having the diffractive optical element according to any one of claims 1 to 12 and a lens.

[0028]
The observation optical system of the invention of claim 16 is characterized by having the diffractive optical element according to any one of claims 1 to 12 and a lens.

Claims (16)

In a diffractive optical element in which a plurality of diffraction gratings having different Abbe numbers are stacked, a plastic material or an ultraviolet curing resin having an Abbe number of 25 or less is used for at least one diffraction grating, and an Abbe number is used for another at least one diffraction grating. A diffractive optical element characterized by using 40 or more materials . In a diffractive optical element having a grating structure in which a plurality of diffraction gratings having different Abbe numbers are stacked, the diffraction efficiency of diffracted light of a specific order is increased over the entire use wavelength region , the Abbe number 25 or less in at least one diffraction grating. A diffractive optical element comprising: a plastic material or an ultraviolet curable resin according to claim 1; and a material having an Abbe number of 40 or more for at least one other diffraction grating . In a diffractive optical element in which a plurality of diffraction gratings having different Abbe numbers are stacked, the grating thickness of each of the plurality of diffraction gratings is 10 μm or less, and a plastic material or an ultraviolet curing resin having an Abbe number 25 or less for at least one diffraction grating And a material having an Abbe number of 40 or more for at least one other diffraction grating . In a diffractive optical element having a grating structure in which a plurality of diffraction gratings having different Abbe numbers are stacked to increase the diffraction efficiency of diffracted light of a specific order in the entire used wavelength region, the grating thickness of each of the plurality of diffraction gratings is A diffractive optical system characterized by using a plastic material or an ultraviolet curable resin having an Abbe number of 25 or less for at least one diffraction grating at 10 μm or less, and using an Abbe number of 40 or more for the other at least one diffraction grating. element. The diffractive optical element according to claim 1, 2, 3 or 4, characterized in that each of the grating thickness of said plurality of diffraction gratings is less than 7.5 [mu] m. A diffraction grating using the Abbe number 25 following material through an air layer, any one of claims 1 to 5, characterized in that are laminated with a diffraction grating using the Abbe number of 40 or more materials The diffractive optical element according to claim 1. The diffraction according to any one of claims 1 to 6 , wherein each of the plurality of diffraction gratings satisfies d / P <1/6, where P is a grating pitch and d is a grating thickness. Optical element. The diffractive optical element according to any one of claims 1 to 7 , wherein each of the plurality of diffraction gratings satisfies 1 <d <6 when the grating thickness is d (μm). The diffractive optical element according to any one of claims 1 to 8, wherein a used wavelength range is a visible range. The plurality of diffraction gratings are formed on a transparent substrate, and the diffraction grating closest to the transparent substrate among the plurality of diffraction gratings is made of the same material as the transparent substrate. The diffractive optical element according to any one of claims 9 to 10. The diffractive optical element according to any one of claims 1 to 10 , wherein the diffractive optical element is designed to have a diffraction efficiency of 97% or more over the entire use wavelength range. The diffractive optical element according to any one of claims 1 to 10 , wherein the diffraction efficiency is designed to be 99% or more for each of the d line, the F line and the C line. An optical system comprising the diffractive optical element according to any one of claims 1 to 12 and a lens. An imaging optical system comprising the diffractive optical element according to any one of claims 1 to 12 and a lens. An imaging optical system comprising the diffractive optical element according to any one of claims 1 to 12 and a lens. An observation optical system comprising the diffractive optical element according to any one of claims 1 to 12 and a lens.