阅读说明：本技术 一种投影物镜 (Projection objective ) 是由 陈超 于 2019-01-30 设计创作，主要内容包括：本发明公开了一种投影物镜,包括从物侧至像侧依次设置在同一光轴上的第一透镜、第二透镜、第三透镜、第四透镜、第五透镜及第六透镜,且满足以下关系式：-3.6<f1/f<-2.9,-1.6<f2/f<-1.0,2.0<f3/f<2.5,-3.1<f4/f<2.5,2.8<f5/f<3.5,3.2<f6/f<3.9,TTL<25mm,FOV<55°。其中,fn为第n透镜的焦距,f为整个投影物镜的焦距,TTL为第一透镜的物侧面到像面的距离,FOV为投影物镜的最大视场角范围；第三透镜与第四透镜之间设置有光阑。通过在光学系统中引入正场曲来使弧型像面放大成像于一平面,使用较少的镜片,校正多种像差,实现清晰成像。(The invention discloses a projection objective which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged on the same optical axis from an object side to an image side, and the following relational expressions are satisfied, wherein 3.6< f1/f < -2.9, -1.6< f2/f < -1.0, 2.0< f3/f <2.5, -3.1< f4/f <2.5, 2.8< f5/f <3.5, 3.2< f6/f <3.9, TT L <25mm and FOV <55 degrees, wherein fn is the focal length of the nth lens, f is the focal length of the whole projection objective, TT L is the distance from the object side surface to the image surface of the first lens, the FOV is the maximum field angle of the projection objective, a diaphragm is arranged between the third lens and the fourth lens, a positive field curvature is introduced into an optical system, the image is clearly corrected by using a plurality of enlarging curved surfaces, and the image is formed by a plurality of planar images.)

1. A projection objective lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are arranged on the same optical axis in sequence from an object side to an image side, and the following relational expressions are satisfied:

-3.6<f1/f<-2.9，

-1.6<f2/f<-1.0，

2.0<f3/f<2.5，

-3.1<f4/f<2.5，

2.8<f5/f<3.5，

3.2<f6/f<3.9，

TTL<25mm，

FOV<55°，

wherein f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f is the focal length of the whole projection objective lens, TT L is the distance from the object side surface of the first lens to the image surface of the projection objective lens, and FOV is the maximum field angle range of the projection objective lens;

and a diaphragm is arranged between the third lens and the fourth lens.

2. A projection objective as claimed in claim 1, characterized in that the first lens element is a meniscus lens element, the object-side surface of the first lens element being convex and the image-side surface of the first lens element being concave; the second lens is a biconcave lens; the third lens is a plano-convex lens, the object side surface of the third lens is a plane, and the image side surface of the third lens is a convex surface; the fourth lens is a biconcave lens; the fifth lens is a plano-convex lens, the object side surface of the fifth lens is a plane, and the image side surface of the fifth lens is a convex surface; the sixth lens is a biconvex lens.

3. A projection objective as claimed in claim 1 or 2, characterized in that the following relationship is also satisfied:

1.89<n1<0.95，

1.70<n2<1.76，

1.80<n3<1.86，

1.89<n4<0.95，

1.70<n5<1.76，

1.70<n6<1.76，

where n1 is a refractive index of the first lens, n2 is a refractive index of the second lens, n3 is a refractive index of the third lens, n4 is a refractive index of the fourth lens, n5 is a refractive index of the fifth lens, and n6 is a refractive index of the sixth lens.

4. A projection objective as claimed in any one of claims 1 to 3, characterized in that the following relationship is also satisfied:

15.9<v1<21.9，

51.7<v2<57.7，

39.7<v3<45.7，

15.9<v4<21.9，

51.7<v5<57.7，

51.7<v6<57.7，

wherein v1 is the abbe number of the first lens, v2 is the abbe number of the second lens, v3 is the abbe number of the third lens, v4 is the abbe number of the fourth lens, v5 is the abbe number of the fifth lens, and v6 is the abbe number of the sixth lens.

5. Projection objective according to claim 1, characterized in that the material of the first lens and the fourth lens is the same.

6. A projection objective as claimed in claim 1, characterized in that the second lens, the fifth lens and the sixth lens are of the same material.

Technical Field

The present invention relates to projection optical systems, and more particularly to a projection objective.

Background

The optical fiber scanner generally comprises a driver and an optical fiber mounted on the driver in a cantilever supporting manner, the optical fiber cantilever is driven by the driver to perform two-dimensional scanning, and since the optical fiber cantilever and the driver are both vibrating, an image plane scanned by the optical fiber scanner is an arc surface, and the light direction is perpendicular to a section of a light emitting surface.

The projection objective is used for imaging an arc-shaped pattern on an image plane of the projection objective onto an object plane of the projection objective, but the image plane (namely the image plane of an image source) of the existing projection objective is generally a plane, but because the image plane scanned by the optical fiber scanner is an arc surface and the light direction is perpendicular to a tangent plane of a light-emitting surface, the existing projection objective cannot solve the imaging problem of the optical fiber scanner, and the image scanned by the optical fiber scanner is difficult to be clearly magnified and imaged on the plane.

Disclosure of Invention

The embodiment of the invention provides a projection objective lens which is used for solving the problem of arc image surface imaging.

To achieve the above object, a first aspect of the embodiments of the present invention provides a projection objective for imaging an arc-shaped pattern on an image plane of the projection objective onto an object plane of the projection objective, the arc-shaped pattern being an arc-shaped image plane scanned by a fiber-optic scanner or emitted from another image source.

The projection objective comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are arranged on the same optical axis in sequence from an object side to an image side, and the following relational expressions are satisfied:

-3.6<f1/f<-2.9，

-1.6<f2/f<-1.0，

2.0<f3/f<2.5，

-3.1<f4/f<2.5，

2.8<f5/f<3.5，

3.2<f6/f<3.9，

TTL<25mm，

FOV<55°，

wherein f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f is the focal length of the whole projection objective lens, TT L is the distance from the object side surface of the first lens to the image surface of the projection objective lens, and FOV is the maximum field angle range of the projection objective lens;

and a diaphragm is arranged between the third lens and the fourth lens.

Preferably, the first lens element is a meniscus lens element, the object-side surface of which is convex and the image-side surface of which is concave; the second lens is a biconcave lens, and both the object side surface and the image side surface of the second lens are concave surfaces; the third lens is a plano-convex lens, the object side surface of the third lens is a plane, and the image side surface of the third lens is a convex surface; the fourth lens is a biconcave lens, and the object side surface and the image side surface of the fourth lens are both concave surfaces; the fifth lens is a plano-convex lens, the object side surface of the fifth lens is a plane, and the image side surface of the fifth lens is a convex surface; the sixth lens element is a biconvex lens element, and both the object-side surface and the image-side surface are convex.

The object side surface is convex, which means that the object side surface faces the object surface to form a convex shape; the object side surface is a concave surface, which means that the object side surface faces the object surface to form a concave shape; the image side surface is convex, namely the image side surface is convex towards the image surface; the image side surface is concave, which is a shape in which the image side surface is recessed toward the image plane.

Preferably, the projection objective further satisfies the following relation:

1.89<n1<0.95，

1.70<n2<1.76，

1.80<n3<1.86，

1.89<n4<0.95，

1.70<n5<1.76，

1.70<n6<1.76，

where n1 is a refractive index of the first lens, n2 is a refractive index of the second lens, n3 is a refractive index of the third lens, n4 is a refractive index of the fourth lens, n5 is a refractive index of the fifth lens, and n6 is a refractive index of the sixth lens.

Preferably, the projection objective further satisfies the following relation:

15.9<v1<21.9，

51.7<v2<57.7，

39.7<v3<45.7，

15.9<v4<21.9，

51.7<v5<57.7，

51.7<v6<57.7，

wherein v1 is the abbe number of the first lens, v2 is the abbe number of the second lens, v3 is the abbe number of the third lens, v4 is the abbe number of the fourth lens, v5 is the abbe number of the fifth lens, and v6 is the abbe number of the sixth lens.

Further preferably, the first lens and the fourth lens are made of the same material.

Further preferably, the second lens, the fifth lens and the sixth lens are made of the same material. Preferably, the wavelength range of the light beam emitted by the image source to which the projection objective of the present invention is applied is 380-780 nm.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages: the positive curvature of field is introduced into an optical system to enable an arc-shaped image surface of an image source (such as an optical fiber scanner) to be magnified and imaged on a plane, the surface type is reasonably optimized, the focal power is reasonably distributed, fewer lenses and fewer glass materials are used, various aberrations are corrected, and clear imaging is realized.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a field curvature diagram of an embodiment of the projection objective according to the invention;

FIG. 3 is a distortion diagram of an embodiment of the projection objective according to the invention;

fig. 4 is a diagram of a transfer function of an embodiment of the projection objective according to the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention provides a projection objective lens which is used for solving the problem of arc-shaped image surface imaging. As shown in fig. 1, for imaging an arc-shaped pattern on the image plane 8 of a projection objective onto the object plane 9 of the projection objective, the arc-shaped pattern being an arc-shaped image plane scanned by a fiber-optic scanner or emitted by another image source.

As shown in fig. 1, the projection objective includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6, which are arranged on the same optical axis in order from an object side to an image side, and satisfy the following relations:

-3.6<f1/f<-2.9，

-1.6<f2/f<-1.0，

2.0<f3/f<2.5，

-3.1<f4/f<2.5，

2.8<f5/f<3.5，

3.2<f6/f<3.9，

TTL<25mm，

FOV<55°，

wherein f1 is the focal length of the first lens 1, f2 is the focal length of the second lens 2, f3 is the focal length of the third lens 3, f4 is the focal length of the fourth lens 4, f5 is the focal length of the fifth lens 5, f6 is the focal length of the sixth lens 6, f is the focal length of the entire projection objective lens, TT L is the distance from the object side 11 of the first lens 1 to the image plane 8 of the projection objective lens, and FOV is the maximum field angle range of the projection objective lens;

a diaphragm 7 is arranged between the third lens 3 and the fourth lens 4.

The specific value of f is not limited and can be selected to be any value according to specific working conditions. When the pattern placed on the image plane 8 is an image scanned by a fiber scanner, the preferred value range of f is 0.5mm-2 mm.

Preferably, the first lens element 1 is a meniscus lens element, and the object-side surface 11 is a convex surface and the image-side surface 12 is a concave surface; the second lens 2 is a biconcave lens, and both the object side surface 21 and the image side surface 22 are concave surfaces; the third lens 3 is a plano-convex lens, an object side surface 31 of the third lens 3 is a plane, and an image side surface 32 of the third lens 3 is a convex surface; the fourth lens element 4 is a biconcave lens element, and both the object-side surface 41 and the image-side surface 42 are concave; the fifth lens 5 is a plano-convex lens, the object-side surface 51 of the fifth lens 5 is a plane, and the image-side surface 52 of the fifth lens 5 is a convex surface; the sixth lens element 6 is a biconvex lens element, and has a convex object-side surface 61 and a convex image-side surface 62.

The object side surface is a convex surface, which means that the object side surface faces the object surface 9 of the projection objective to form a convex shape; the object side surface is a concave surface, which means that the object side surface faces the object surface 9 to form a concave shape; the image side surface is convex, namely the image side surface faces the image surface 8 of the projection objective and is in a convex shape; the image side surface is concave, and is recessed toward the image plane 8.

More preferably, the refractive index of each lens should satisfy the following relation,

1.89<n1<0.95，

1.70<n2<1.76，

1.80<n3<1.86，

1.89<n4<0.95，

1.70<n5<1.76，

1.70<n6<1.76，

where n1 is a refractive index of the first lens 1, n2 is a refractive index of the second lens 2, n3 is a refractive index of the third lens 3, n4 is a refractive index of the fourth lens 4, n5 is a refractive index of the fifth lens 5, and n6 is a refractive index of the sixth lens 6.

More preferably, the abbe number of each lens material satisfies the following relational expression,

15.9<v1<21.9，

51.7<v2<57.7，

39.7<v3<45.7，

15.9<v4<21.9，

51.7<v5<57.7，

51.7<v6<57.7，

where v1 is the abbe number of the first lens 1, v2 is the abbe number of the second lens 2, v3 is the abbe number of the third lens 3, v4 is the abbe number of the fourth lens 4, v5 is the abbe number of the fifth lens 5, and v6 is the abbe number of the sixth lens 6.

Further preferably, the first lens 1 and the fourth lens 4 are made of the same material.

Further preferably, the second lens 2, the fifth lens 5 and the sixth lens 6 are made of the same material.

Preferably, the wavelength range of the light beam emitted by the image source to which the projection objective of the present invention is applied is 380-780 nm.

In one embodiment of the present invention, each lens of the projection objective is made of glass, the focal length of the entire projection objective is 1.218mm, and the focal length, refractive index and abbe number of each lens are shown in the following table:

further, the thickness parameters and the pitch parameters of each optical device in this embodiment are shown in the following table:

noodle	Radius of curvature (mm)	Distance number	Thickness/spacing (mm)
				Article surface	Infinity(s)	TW	1000.000
11	4.414	T1	1.993
				12	1.600	T12	0.800
21	-2.612	T2	1.288
				22	2.612	T23	0.300
31	Infinity(s)	T3	1.857
				32	-2.331	T30	3.812
Diaphragm	Infinity(s)	T04	3.219
				41	-12.904	T4	1.313
42	4.514	T45	0.289
				51	Infinity(s)	T5	1.126
52	-2.840	T56	1.381
				61	3.641	T6	1.270
62	-22.666	TX	3.000
				Image plane	2.700

Where Tw is an axial distance between the object plane 9 of the projection objective and the object-side surface 11 of the first lens element 1, T1 is a thickness of the first lens element 1, T12 is an axial distance between the image-side surface 12 of the first lens element 1 and the object-side surface 21 of the second lens element 2, T2 is a thickness of the second lens element 2, T23 is an axial distance between the image-side surface 22 of the second lens element 2 and the object-side surface 31 of the third lens element 3, T3 is a thickness of the third lens element 3, T30 is an axial distance between the image-side surface 31 of the third lens element 3 and the stop 7, T04 is an axial distance between the stop 7 and the object-side surface 41 of the fourth lens element 4, T4 is a thickness of the fourth lens element 4, T45 is an axial distance between the image-side surface 42 of the fourth lens element 4 and the object-side surface 51 of the fifth lens element 5, T5 is a thickness of the fifth lens element 5, and T56 is an axial distance between the image-side surface 52 of the fifth lens element 5 and the object-side surface 61 of the sixth lens element 6, t6 is the thickness of the sixth lens 6, and TX is the distance from the image side surface 62 of the sixth lens 6 to the image plane 8 of the projection objective on the optical axis. The projection objective of this embodiment has a magnification of 830 at 1 meter.

Fig. 2 is a graph of the field curvature of the projection objective shown in fig. 1, fig. 3 is a graph of the distortion of the projection objective shown in fig. 1, and fig. 4 is a graph of the transfer function of the projection objective shown in fig. 1. As can be seen from fig. 2 and 3, the distortion is good over the full field of view. From the graph shown in fig. 4, the imaging resolution is good.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" or "comprises" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The use of the words first, second, third, etc. do not denote any order, but rather the words are to be construed as names.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages: the positive curvature of field is introduced into an optical system to enable an arc-shaped image surface of an image source (such as an optical fiber scanner) to be magnified and imaged on a plane, the surface type is reasonably optimized, the focal power is reasonably distributed, fewer lenses and fewer glass materials are used, various aberrations are corrected, and clear imaging is realized.

All features disclosed in this specification, except features that are mutually exclusive, may be combined in any way.

Any feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.