Optical lens with antireflective film, projection lens, and projection lens optical system

Patent metadata

Field	Value
Publication number	US-11846754-B2
Application number	US-202017127332-A
Country	US
Kind code	B2
Filing date	Dec 18, 2020
Priority date	Dec 25, 2019
Publication date	Dec 19, 2023
Grant date	Dec 19, 2023

Abstract

An optical lens with an antireflective film includes: a lens substrate; and an antireflective film disposed on the lens substrate. The antireflective film is formed of layers each having a physical thickness of 140 nm or less. In order from an air side, the antireflective film has: a first layer formed as an MgF2 layer, a second layer, a fourth layer, a sixth layer, an eighth layer, and a tenth layer each having a refractive index of 2.0 or more and 2.3 or less, and a third layer, a fifth layer, a seventh layer, and a ninth layer each formed as an SiO2 layer.

First claim

What is claimed is:

1. An optical lens with an antireflective film, comprising:
a lens substrate; and
an antireflective film disposed on the lens substrate, wherein
the antireflective film is formed of layers each having a physical thickness of 140 nm or less,
in order from an air side, the antireflective film has:
a first layer formed as an MgF 2 layer,
a second layer, a fourth layer, a sixth layer, an eighth layer, and a tenth layer each having a refractive index of 2.0 or more and 2.3 or less, and
a third layer, a fifth layer, a seventh layer, and a ninth layer each formed as an SiO 2 layer, and

quarter wave optical thicknesses Q 1 , Q 2 , Q 3 , Q 4 , Q 5 , Q 6 , Q 7 , Q 8 , Q 9 , and Q 10 of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth layers, respectively, in a design reference wavelength λ 0 of 550 nm satisfy equations (1), (2), (3), (4), (5), (6), (7), (8), (9), and (10), respectively:
Q 1 =0.05× n s +A 1(0.79≤ A 1≤0.91);  Equation (1)

Q 2 =0.09× n s +A 2(1.64≤ A 2≤1.85);  Equation (2)

Q 3 =A 3(0.68≤ A 3≤1.02);  Equation (3)

Q 4 =A 4(0.02≤ A 4≤0.22);  Equation (4)

Q 5 =A 5(0.68≤ A 5≤1.02);  Equation (5)

Q 6 =−0.31× n s +A 6(1.01≤ A 6≤1.29);  Equation (6)

Q 7 =A 7(0.10≤ A 7≤0.35);  Equation (7)

Q 8 =0.79× n s +A 8(−1.64≤ A 8≤0.01);  Equation (8)

Q 9 =−0.64× n s +A 9(1.26≤ A 9≤1.55); and  Equation (9)

Q 10 =0.32× n s +A 10(−0.38≤ A 10≤0.19),  Equation (10)

where n s shows a refractive index of the lens substrate in a wavelength of 587.56 nm,
each of the quarter wave optical thicknesses of the respective layers of the antireflective film in the design reference wavelength is obtained by dividing an optical thickness of each of the layers of the antireflective film by λ 0 /4, and
the optical thickness of each of the layers of the antireflective film is obtained by a product of: the refractive index of each of the layers of the antireflective film in the design reference wavelength and the physical thickness (nm) of each of the layers of the antireflective film.

2. The optical lens with an antireflective film according to claim 1 , wherein each of the second layer, the fourth layer, the sixth layer, the eighth layer, and the tenth layer is one of:
a Ta 2 O 5 layer,
an LaTiO 3 layer,
a layer formed of a mixture of Ti 2 O 3 and ZrO 2 ,
a layer formed of a mixture of ZrTiO 4 and ZrO 2 ,
an Nb 2 O 5 layer, or
a TiO 2 layer.

3. The optical lens with an antireflective film according to claim 1 , wherein a maximum reflectance of the antireflective film in a wavelength range of 430 nm or more and 670 nm or less is 0.2% or less.

4. A projection lens comprising the optical lens according to claim 1 .

5. A projection lens optical system comprising a plurality of optical lenses according to claim 1 .

6. A projection lens optical system comprising:
a first projection lens comprising the optical lens according to claim 1 ;
a second projection lens comprising the optical lens according to claim 1 ; and
a third projection lens comprising the optical lens according to claim 1 , wherein
a first refractive index of a lens substrate of the first projection lens, a second refractive index of a lens substrate of the second projection lens, and a third refractive index of a lens substrate of the third projection lens satisfy a first equation, a second equation, and a third equation, respectively, and
the first equation, the second equation, and the third equation are selected from equations (11), (12), (13), (14), (15), and (16) and are different from each other:
1.35 ≤n s <1.45;  Equation (11)

1.45 ≤n s <1.55;  Equation (12)

1.55 ≤n s <1.65;  Equation (13)

1.65 ≤n s <1.75;  Equation (14)

1.75 ≤n s <1.85; and  Equation (15)

1.85 ≤n s <1.95.  Equation (16)

Assignees

• Konica Minolta Inc

Inventors

• Nakano Yoshihiro
• Takahara Koji

Classifications

• G02B1/115 Primary

  Multilayers · CPC title

• C01F5/28

  Fluorides · CPC title

• C01G23/003

  Titanates (C01G23/001 takes precedence) · CPC title

• C01G23/047

  Titanium dioxide · CPC title

• C01G25/006

  Compounds containing zirconium, with or without oxygen or hydrogen, and containing two or more other elements · CPC title