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US 2026/0177792 A1Published application
Projection lens
AssigneeYoung Optics Inc.
InventorsSHUO-CHIEH CHANG, KUO-CHUAN WANG
Life of this patent
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Abstract
A projection lens includes a first lens group, an aperture stop and a second lens group arranged in order from a magnified side to a minified side. The projection lens satisfies the following conditions: (1) 0.2<BFL/EFL<0.6, where EFL is an effective focal length of the projection lens, and BFL is a back focal length of the projection lens; and (2) an axial distance between any pair of lenses in the projection lens remains constant during operation.
Claims20
A projection lens, comprising:
- a first lens group, an aperture stop and a second lens group arranged in order from a magnified side to a minified side of the projection lens, the first lens group consisting essentially of four or five lenses, the four or five lenses including an aspheric lens disposed at a position corresponding to a first or second lens as counted from the magnified side toward the minified side, the second lens group consisting essentially of five or six lenses, the five or six lenses including a cemented doublet and an aspheric lens, the aspheric lens of the second lens group being located at a position closest to the minified side,
- wherein a total number of aspheric lenses in the projection lens is less than or equal to 3, and the projection lens satisfies the following conditions:
- (1) 0.2<BFL/EFL<0.6, where EFL is an effective focal length of the projection lens, and BFL is a back focal length of the projection lens;
- and
- (2) an axial distance between any pair of lenses in the projection lens remains constant during operation.
2 more elements
A projection lens, comprising:
- a first lens group, an aperture stop and a second lens group arranged in order from a magnified side to a minified side of the projection lens, the first lens group consisting essentially of four or five lenses, a first lens or a second lens as counted from the magnified side toward the minified side being a molded glass aspheric lens, the second lens group consisting essentially of five or six lenses, the five or six lenses including a cemented doublet and a molded glass aspheric lens disposed at a position closest to the minified side, wherein the projection lens satisfies the following conditions:
- (1) 0.02<BFL/D<0.06, where BFL is a back focal length of the projection lens, and D is a distance measured on an optical axis of the projection lens between a lens surface of the projection lens closest to the magnified side and a lens surface of the projection lens closest to the minified side;
- (2) an axial distance between any pair of lenses in the projection lens remains constant during operation;
- and
- (3) a total number of aspheric lenses in the projection lens is less than or equal to 3.
2 more elements
A projection lens, comprising:
- a first lens group, an aperture stop and a second lens group arranged in order from a magnified side to a minified side of the projection lens, the first lens group consisting essentially of four or five lenses, and the four or five lenses including a first aspheric lens disposed at a position corresponding to a first or second lens as counted from the magnified side toward the minified side, the second lens group consisting essentially of five or six lenses, the five or six lenses including a cemented doublet and a second aspheric lens, and the second aspheric lens of the second lens group being located at a position closest to the minified side,
- wherein a total number of aspheric lenses in the projection lens is less than or equal to 3, and the projection lens satisfies the following conditions:
- (1) a depth of field range is defined by EFL/D, where EFL is an effective focal length of the projection lens, and D is a distance measured on an optical axis of the projection lens between a lens surface of the projection lens closest to the magnified side and a lens surface of the projection lens closest to the minified side, and the depth of field range is in a range between 0.075 and 0.19;
- and
- (2) an axial distance between any pair of lenses in the projection lens remains constant during operation.
2 more elements
Dependencies are inferred from the claim text.