Optical lens and projection apparatus

Patent metadata

Field	Value
Publication number	US-11899170-B2
Application number	US-202016918265-A
Country	US
Kind code	B2
Filing date	Jul 1, 2020
Priority date	Jul 1, 2019
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

An optical lens includes a first lens with a positive refractive power, a second lens having a diffractive optical surface and a negative refractive power, and a third lens with a positive refractive power arranged in order from a magnified side to a minified side. A total number of lenses with refractive powers in the optical lens is smaller than six, and the first lens, the second lens and the third lens are made of plastic.

First claim

What is claimed is:

1. A projection lens, comprising:
a first lens with a positive refractive power, a second lens having a diffractive optical surface and a negative refractive power, and a third lens with a positive refractive power arranged in order from a magnified side to a minified side, a total number of lenses with refractive powers in the projection lens being smaller than six, and the first lens, the second lens and the third lens of the projection lens being aspheric lenses and made of plastic.

2. The projection lens as claimed in claim 1 , wherein the projection lens further comprises a lens with a negative refractive power disposed between the first lens and the second lens.

3. The projection lens as claimed in claim 1 , wherein a depth of the diffractive optical surface is in the range of 0.29 um-2.5 um.

4. The projection lens as claimed in claim 1 , wherein the projection lens further comprises an aperture stop, and a distance between the aperture stop and the diffractive optical surface is kept fixed.

5. The projection lens as claimed in claim 1 , wherein the projection lens further includes a Fresnel lens with a refractive power.

6. The projection lens as claimed in claim 1 , wherein the first lens and the third lens are made of PMMA, and the second lens is made of EP5000 plastic.

7. The projection lens as claimed in claim 1 , wherein the first lens and the third lens are made of PMMA, and the second lens is made of E48R plastic.

8. The projection lens as claimed in claim 1 , wherein the first lens, the second lens and the third lens are made of PMMA.

9. A projection apparatus, comprising:
a light source;
a light valve disposed downstream from and in a light path of the light source; and
an optical lens disposed downstream from and in a light path of the light valve, the optical lens comprising a first lens with a positive refractive power, a second lens having a diffractive optical surface and a negative refractive power, and a third lens with a positive refractive power arranged in order from a magnified side to a minified side, a total number of lenses with refractive powers in the optical lens being smaller than six, and the first lens, the second lens and the third lens being aspheric lenses and made of plastic.

10. The projection apparatus as claimed in claim 9 , wherein the optical lens further comprises a lens with a negative refractive power disposed between the first lens and the second lens.

11. The projection apparatus as claimed in claim 9 , wherein a depth of the diffractive optical surface is in the range of 0.29 um-2.5 um.

12. The projection apparatus as claimed in claim 9 , wherein the optical lens further comprises an aperture stop, and a distance between the aperture stop and the diffractive optical surface is kept fixed.

13. The projection apparatus as claimed in claim 9 , wherein the optical lens further includes a Fresnel lens with a refractive power.

14. A projection apparatus, comprising:
a light source;
a light valve disposed downstream from and in a light path of the light source; and
an optical lens disposed downstream from and in a light path of the light valve, the optical lens consisting essentially of a first lens, a second lens, and a third lens arranged in order in a direction, the second lens having at least one diffractive optical surface, the first lens, the second lens and the third lens being aspheric lenses and made of plastic, and a total number of lenses with refractive powers in the optical lens being smaller than six, wherein a depth of the at least one diffractive optical surface is in the range of 0.29 um-2.5 um, and the projection apparatus is configured for projecting a real image.

15. The projection apparatus as claimed in claim 14 , wherein the optical lens further comprises an aperture stop, and a distance between the aperture stop and the diffractive optical surface is kept fixed.

16. The projection apparatus as claimed in claim 14 , wherein the optical lens further includes a Fresnel lens with a refractive power.

Assignees

• Young Optics Inc

Inventors

• Lin Yu-Chen
• Wu Chun-Tung

Classifications

• G02B13/004 Primary

  having four lenses · CPC title

• G02B1/041

  Lenses · CPC title

• G02B9/34

  having four components only · CPC title

• G02B13/0055

  employing a special optical element · 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