Projection lens

Patent metadata

Field	Value
Publication number	US-11714266-B2
Application number	US-201816644966-A
Country	US
Kind code	B2
Filing date	Nov 8, 2018
Priority date	Mar 9, 2018
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

The disclosure discloses a projection lens, which sequentially includes a first lens, a second lens and a third lens from an image source side to an imaging side along an optical axis. The first lens has a positive refractive power, and a surface near the image source side thereof is a convex surface. The second lens has a positive refractive power or negative refractive power. The third lens has a positive refractive power is a meniscus lens of which a surface near the imaging side is a convex surface. An image source height ImgH of the projection lens and a total effective focal length f of the projection lens meet ImgH/f<0.2.

First claim

What is claimed is:

1. A projection lens, comprising a first lens, a second lens and a third lens which are provided in sequence from an image source side to an imaging side along an optical axis, wherein
the first lens has a positive refractive power, and a surface near the image source side of the first lens is a convex surface;
the second lens has a positive refractive power or a negative refractive power;
the third lens has a positive refractive power and the third lens is a meniscus lens of which a surface near the imaging side is a convex surface; and
an image source height ImgH of the projection lens and a total effective focal length f of the projection lens meet ImgH/f<0.2;
a maximum incident angle CRAmax of a primary ray of the projection lens and a maximum half field of view HFOV of the projection lens meet tan(CRAmax)+tan(HFOV)<0.3.

2. The projection lens as claimed in claim 1 , wherein a radius of curvature R6 of the surface near the imaging side of the third lens and the total effective focal length f of the projection lens meet R6/f>−1.

3. The projection lens as claimed in claim 2 , wherein a radius of curvature R1 of the surface near the image source side of the first lens and the radius of curvature R6 of the surface near the imaging side of the third lens meet −1.2<R1/R6<−0.8.

4. The projection lens as claimed in claim 1 , wherein an effective focal length f3 of the third lens and the total effective focal length f of the projection lens meet 0<f3/f<1.

5. The projection lens as claimed in claim 1 , wherein a spacing distance T12 between the first lens and the second lens on the optical axis, a spacing distance T23 between the second lens and the third lens on the optical axis and a spacing distance Td between the surface near the image source side of the first lens and the surface near the imaging side of the third lens on the optical axis meet 0.3<(T12+T23)/Td<0.7.

6. The projection lens as claimed in claim 1 , wherein a radius of curvature R5 of a surface near the image source side of the third lens and a radius of curvature R6 of the surface near the imaging side of the third lens meet 0<|(R5−R6)/(R5+R6)|<1.

7. The projection lens as claimed in claim 1 , wherein a center thickness CT1 of the first lens on the optical axis and a sum ΣCT of a center thicknesses of the first lens on the optical axis, a center thicknesses of the second lens on the optical axis and a center thicknesses of the third lens on the optical axis meet 0.25<CT1/ΣCT<0.6.

8. The projection lens as claimed in claim 1 , wherein a SAG11 and a SAG32 meet −1.5<SAG11/SAG32<−0.5, the SAG11 is an on-axis distance from an intersection of the surface near the image source side of the first lens and the optical axis to a maximum effective semi-diameter vertex of the surface near the image source side of the first lens, the SAG32 is an from an on-axis distance from an intersection of the surface near the imaging side of the third lens and the optical axis to a maximum effective semi-diameter vertex of the surface near the imaging side of the third lens.

9. The projection lens as claimed in claim 1 , wherein a SAG11 and a SAG32 meet SAG31/SAG32<0.5, the SAG31 is an on-axis distance from an intersection of a surface near an image source side of the third lens and the optical axis to a maximum effective semi-diameter vertex of the surface near the imaging side of the third lens, the SAG32 is an on-axis distance from an intersection of the surface near the imaging side of the third lens and the optical axis to the maximum effective semi-diameter vertex of the surface near the imaging side of the third lens.

10. The projection lens as claimed in claim 1 , wherein a maximum effective semi-diameter DT11 of the surface near the image source side of the first lens and a maximum effective semi-diameter DT21 of a surface near the image source side of the second lens meet 1.2<DT11/DT21<2.

11. The projection lens as claimed in claim 1 , wherein an effective focal length f1 of the first lens, an effective focal length f3 of the third lens and the total effective focal length f of the projection lens meet 0.5<(f1+f3)/f<1.5.

12. The projection lens as claimed in claim 1 , wherein the projection lens meets 0.5<|SAG11/DT11|/|SAG32/DT32|<1.5,
and SAG11 is an on-axis distance from an intersection of the surface near the image source side of the first lens and the optical axis to a maximum effective semi-diameter vertex of the surface near the image source side of the first lens,
DT11 is the maximum effective semi-diameter of the surface near the image source side of the first lens,
SAG32 is an on-axis distance from an intersection of the surface near the imaging side of the third lens and the optical axis to a maximum effective semi-diameter vertex of the surface near the imaging side of the third lens, and
DT32 is the maximum effective semi-diameter of the surface near the imaging side of the third lens.

13. The projection lens as claimed in claim 1 , wherein an object space numerical aperture NA of the projection lens meets 0.18≤NA<0.3.

14. The projection lens as claimed in claim 1 , wherein a minimum wavelength of a practically used wavelength λ of the projection lens is 0 nm to 100 nm less than a minimum wavelength of a used light source, and a maximum wavelength of the practically used wavelength λ of the projection lens is 0 nm to 100 nm greater than a maximum wavelength of the used light source.

15. The projection lens as claimed in claim 1 , wherein a refractive index N2 of the second lens and a refractive index N3 of the third lens meet N2≤N3.

16. A projection lens, comprising a first lens, a second lens and a third lens which are provided in sequence from an image source side to an imaging side along an optical axis, wherein
the first lens has a positive refractive power, and a surface near the image source side of the first lens is a convex surface;
the second lens has a negative refractive power;
the third lens has a positive refractive power and is a meniscus lens of which a surface near an imaging side is a convex surface; and
a radius of curvature R1 of the surface near the image source side of the first lens and a radius of curvature R6 of the surface near the imaging side of the third lens meet −1.2<R1/R6<−0.8;
a maximum incident angle CRAmax of a primary ray of the projection lens and a maximum half field of view HFOV of the projection lens meet tan(CRAmax)+tan(HFOV)<0.3.

17. The projection lens as claimed in claim 16 , wherein a refractive index N2 of the second lens and a refractive index N3 of the third lens meet N2≤N3.

18. The projection lens as claimed in claim 16 , wherein an object space numerical aperture NA of the projection lens meets 0.18≤NA<0.3.

19. The projection lens as claimed in claim 16 ,
wherein the projection lens meets 0.5<|SAG11/DT11|/|SAG32/DT32|<1.5,
and SAG11 is an on-axis distance from an intersection of the surface near the image source side of the first lens and the optical axis to a maximum effective semi-diameter vertex of the surface near the image source side of the first lens,
DT11 is the maximum effective semi-diameter of the surface near the image source side of the first lens,
SAG32 is an on-axis distance from an intersection of the surface near the imaging side of the third lens and the optical axis to a maximum effective semi-diameter vertex of the surface near the imaging side of the third lens, and
DT32 is the maximum effective semi-diameter of the surface near the imaging side of the third lens.

Assignees

• Zhejiang Sunny Optical Co Ltd

Inventors

• Wang Xinquan
• Huang Lin

Classifications

• G02B13/18 Primary

  with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration {(G02B13/002 takes precedence)} · CPC title

• G02B13/0035

  having three lenses · CPC title

• G02B27/4205

  having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant · CPC title

• G03B21/145

  Housing details, e.g. position adjustments thereof · CPC title

• G02B13/22 Primary

  Telecentric objectives or lens systems · CPC title