CN213582179U - Scanning lens with simple structure - Google Patents

Abstract

The invention provides a scanning lens with a simple structure, which sequentially comprises five parts from an object plane to an image plane: a Stop (STO), a first lens (L1), a second lens (L2), an optical filter (IR), and chip protection glass (CG); wherein the first lens element (L1) is a positive lens element with a concave object-side surface and a convex image-side surface; the second lens element (L2) is a negative lens element with a concave object-side surface and a convex image-side surface. The scanning lens with a simple structure provided by the invention satisfies the following relational expression: 0.52< f1/f < 0.77; -1.2< f2/f < -0.9; wherein f1 is the effective focal length of the first lens (L1), f2 is the effective focal length of the second lens (L2), and f is the effective focal length of the lens. The invention has simple structure, only comprises two optical lenses, has low production cost, easy assembly, mass production and higher imaging quality.

Description

Scanning lens with simple structure

[ technical field ] A method for producing a semiconductor device

The invention relates to a scanning lens with a simple structure.

[ background of the invention ]

In recent years, with the increasing amount of barcode information, more and more image scanning technologies replace the prior laser barcode scanning technologies, a special scanning instrument is often required to be used for accurately and efficiently scanning identification information in a specific occasion, and the market has higher requirements on scanning lenses, including smaller volume, higher imaging quality and lower cost.

The present invention has been made in view of the above market needs.

[ summary of the invention ]

The invention aims to provide a scanning lens with a simple structure, and has the advantages of simple structure, low cost, easy production, small distortion of the lens and higher imaging quality.

In order to achieve the purpose, the invention adopts the following technical scheme:

a scanning lens with a simple structure sequentially comprises five parts from an object plane to an image plane: a Stop (STO), a first lens (L1), a second lens (L2), an optical filter (IR), and chip protection glass (CG); wherein the first lens element (L1) is a positive lens element with a concave object-side surface and a convex image-side surface; the second lens element (L2) is a negative lens element with a concave object-side surface and a convex image-side surface.

The scanning lens with the simple structure meets the following relational expression:

0.52<f1/f<0.77；

-1.2<f2/f<-0.9；

wherein f1 is the effective focal length of the first lens (L1), f2 is the effective focal length of the second lens (L2), and f is the effective focal length of the simple scanning lens.

The scanning lens with the simple structure meets the following relational expression:

10<L/TTL<15；

wherein, TTL is the distance on the optical axis from the object side surface of the first lens (L1) of the scanning lens with simple structure to the image surface, and L is the optimal imaging object distance of the lens.

The scanning lens with the simple structure meets the following relational expression:

0.1<D/f<0.5；

ILL>80％；

wherein, D is the effective diameter of the simple scanning lens diaphragm (STO), f is the effective focal length of the lens, and ILL is the relative illumination of the lens.

The scanning lens with the simple structure meets the following relational expression:

0.72<T1/∑T<0.93；

0.1<T2/∑T<0.33；

t1 and T2 are thicknesses of a first lens (L1) and a second lens (L2) of the scanning lens with the simple structure on an optical axis respectively, and Sigma T is the sum of thicknesses of the first lens (L1) and the second lens (L2) of the scanning lens on the optical axis.

The scanning lens with the simple structure meets the following relational expression:

30<Vd1-Vd2<36；

wherein, Vd1 and Vd2 are abbe numbers of the first lens (L1) and the second lens (L2), respectively, of the scanning lens with the simple structure.

The scanning lens with the simple structure meets the following relational expression:

0.82<f*tan(ω/2)/ImgH<1.2；

where f is the effective focal length of the scanning lens with simple structure, ω is the field angle of the lens, and ImgH is the maximum half-image height of the lens.

[ description of the drawings ]

FIG. 1 is a schematic diagram of an optical system of a scanning lens with a simple structure;

FIG. 2 is a distortion diagram of the optical system of a scanning lens with a simple structure;

fig. 3 is a graph of astigmatism of an optical system of a simple scanning lens.

[ detailed description ] embodiments

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1, the scanning lens with a simple structure provided by the present invention sequentially includes five portions from an object plane to an image plane: a Stop (STO), a first lens (L1), a second lens (L2), an optical filter (IR), and chip protection glass (CG); wherein the first lens element (L1) is a positive lens element with a concave object-side surface and a convex image-side surface; the second lens element (L2) is a negative lens element with a concave object-side surface and a convex image-side surface.

The scanning lens with the simple structure meets the following relational expression:

0.52<f1/f<0.77； (1)

-1.2<f2/f<-0.9； (2)

wherein f1 is the effective focal length of the first lens (L1), f2 is the effective focal length of the second lens (L2), and f is the effective focal length of the simple scanning lens. A simple structure of the scanning lens, only contain two optical lens, use the positive and negative lens way of combining, under satisfying (1), (2) type situation, can shorten the length of the lens effectively, make the lens compact, help correcting astigmatism and controlling the distortion at the same time.

The scanning lens with the simple structure meets the following relational expression:

10<L/TTL<15； (3)

wherein, TTL is the distance on the optical axis from the object side surface of the first lens (L1) of the scanning lens with simple structure to the image surface, and L is the optimal imaging object distance of the lens. The above formula (3) can balance the distant view resolution and the close view resolution of the lens optical system, when the ratio of the optimal object distance to the total lens length is lower than the lower limit, the distant view resolution is deteriorated, and when the ratio is higher than the upper limit, the close view resolution is deteriorated.

The scanning lens with the simple structure meets the following relational expression:

0.1<D/f<0.5； (4)

ILL>80％； (5)

wherein, D is the effective diameter of the simple scanning lens diaphragm (STO), f is the effective focal length of the lens, and ILL is the relative illumination of the lens. The lens diaphragm is a rectangular diaphragm, the diameter of the diaphragm is small, stray light and aberration can be controlled conveniently, incident light flux is increased under the condition that the formulas (4) and (5) are met, and the picture brightness is improved.

The scanning lens with the simple structure meets the following relational expression:

0.72<T1/∑T<0.93； (6)

0.1<T2/∑T<0.33； (7)

t1 and T2 are thicknesses of a first lens (L1) and a second lens (L2) of the scanning lens with the simple structure on an optical axis respectively, and Sigma T is the sum of thicknesses of the first lens (L1) and the second lens (L2) of the scanning lens on the optical axis.

The invention only contains two optical lenses, and under the condition of satisfying the formulas (6) and (7), the thicknesses of the first lens (L1) and the second lens (L2) are moderate, thereby reducing the tolerance sensitivity of the lens optical system and reducing the whole length.

The scanning lens with the simple structure meets the following relational expression:

30<Vd1-Vd2<36； (8)

wherein, Vd1 and Vd2 are abbe numbers of the first lens (L1) and the second lens (L2) of the scanning lens with simple structure respectively. When the lens meets the formula (8), the correction of chromatic aberration and aberration is facilitated, and the conditions of large magnification chromatic aberration and picture color distortion are effectively avoided.

The scanning lens with the simple structure meets the following relational expression:

0.82<f*tan(ω/2)/ImgH<1.2； (9)

where f is the effective focal length of the scanning lens with simple structure, ω is the field angle of the lens, and ImgH is the maximum half-image height of the lens. The formula (9) can be used for restricting the field size of the lens optical system and avoiding that the object height is not met and the optical system is excessively distorted due to overlarge or undersize field angle.

In summary, the scanning lens with a simple structure provided by the invention has the following advantages compared with the prior art:

the invention has simple structure, low cost and mass production, and simultaneously, the rectangular diaphragm is used in the design of the lens, thereby effectively restricting stray light and aberration of the optical system of the lens and leading the lens to have higher imaging quality.

The following table is a table of lens data for specific examples

Table 1 is a simple structure of the scanning lens structure parameter table

Surface	Type	Radius(mm)	Thickness(mm)	Glass
					Object	Sphere	Infinity	99
Stop	Sphere	Infinity	0.02
					2	Asphere	168.178	2.365	1.54:56.2
3	Asphere	-2.224	2.456
					4	Asphere	-3.881	0.430	1.63:23.4
5	Asphere	216.536	0.02
					6	Sphere	Infinity	0.21	1.52:61.2
7	Sphere	Infinity	1.68
					8	Sphere	Infinity	0.3	1.52:61.2
9	Sphere	Infinity	0.13
					Image	Sphere	Infinity	0

Table 2 shows the ratio of rise to radius R of the first lens (L1) of a simple scanning lens

Table 3 shows the ratio of rise to radius R of the second lens (L2) of a simple scanning lens

Claims (7)

1. A scanning lens with a simple structure is characterized by comprising five parts from an object plane to an image plane in sequence: a Stop (STO), a first lens (L1), a second lens (L2), an optical filter (IR), and chip protection glass (CG); wherein the first lens element (L1) is a positive lens element with a concave object-side surface and a convex image-side surface; the second lens element (L2) is a negative lens element with a concave object-side surface and a convex image-side surface.

2. A scanning lens with a simple structure as claimed in claim 1, wherein:

0.52<f1/f<0.77；

-1.2<f2/f<-0.9；

wherein f1 is the effective focal length of the first lens (L1), f2 is the effective focal length of the second lens (L2), and f is the effective focal length of the simple scanning lens.

3. A scanning lens with a simple structure as claimed in claim 1, wherein:

10<L/TTL<15；

wherein, TTL is the distance on the optical axis from the object side surface of the first lens (L1) of the scanning lens with simple structure to the image surface, and L is the optimal imaging object distance of the lens.

4. A scanning lens with a simple structure as claimed in claim 1, wherein:

0.1<D/f<0.5；

ILL>80％；

wherein, D is the effective diameter of the simple scanning lens diaphragm (STO), f is the effective focal length of the lens, and ILL is the relative illumination of the lens.

5. A scanning lens with a simple structure as claimed in claim 1, wherein:

0.72<T1/∑T<0.93；

0.1<T2/∑T<0.33；

t1 and T2 are thicknesses of a first lens (L1) and a second lens (L2) of the scanning lens with the simple structure on an optical axis respectively, and Sigma T is the sum of thicknesses of the first lens (L1) and the second lens (L2) of the scanning lens on the optical axis.

6. A scanning lens with a simple structure as claimed in claim 1, wherein:

30<Vd1-Vd2<36；

wherein, Vd1 and Vd2 are abbe numbers of the first lens (L1) and the second lens (L2) of the scanning lens with simple structure respectively.

7. A scanning lens with a simple structure as claimed in claim 1, wherein:

0.82<f*tan(ω/2)/ImgH<1.2；

where f is the effective focal length of the scanning lens with simple structure, ω is the field angle of the lens, and ImgH is the maximum half-image height of the lens.

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