CN102012553B

CN102012553B - Imaging lens for mobile reading devices

Info

Publication number: CN102012553B
Application number: CN2009101899930A
Authority: CN
Inventors: 肖业卫; 丁晓云; 张斧
Original assignee: SHENZHEN DINGSHI SCIENCE AND TECHNOLOGY Co Ltd
Current assignee: Shenzhen Dingzhi Technology Co ltd
Priority date: 2009-09-08
Filing date: 2009-09-08
Publication date: 2012-01-11
Anticipated expiration: 2029-09-08
Also published as: CN102012553A

Abstract

The invention discloses an imaging lens which is applied to mobile reading devices, such as mobile phones, PDA (personal digital assistant) and the like. The imaging lens is provided with a hollow cylindrical lens barrel, and five eyeglasses are fixed in the lens barrel. From an object side, the five eyeglasses are a first positive lens, a second positive lens, a third negative lens, a fourth positive lens and a fifth positive lens in sequence. The first positive lens is a concave-convex positive lens, the second positive lens is a convex-flat positive lens, the third negative lens is a double-concave negative lens, the fourth positive lens is a double-convex positive lens, and the fifth positive lens is a convex-concave positive lens. As the five eyeglasses of the imaging lens are in a design of positive, positive, negative, positive and positive arrangement and a design of each lens shape, the imaging quality of the imaging lens is increased.

Description

Be used for moving the imaging lens of reading device

Affiliated technical field

The present invention relates to a kind of imaging lens, particularly relate to a kind of camera lens that is used for the imaging of coded graphics symbols such as bar code, two-dimension code, this imaging lens can be used on the mobile reading devices such as mobile phone, PDA.

Background technology

Along with the development of automatic identification technology, more and more widely in the application of adopting coded graphics symbolic representation information such as bar code or two-dimension code such as industries such as retail, logistics, animal traceabilities.

When reading the information of coded graphics symbolic representation, through reading device the coded graphics symbol is carried out to picture earlier usually, and then the image of coded graphics symbol is handled, decoded, thereby obtain the information of coded graphics symbolic representation with imaging lens.Because when the coded graphics symbol being carried out to picture; Because of reading device nearer with coded graphics symbolic distance (aiming at object plane); Usually regulate the camera lens blur-free imaging at the aligning object plane apart from about lens 25cm; Yet when the aligning object plane departed from 25cm, imaging lens had influenced the recognition rate of reading device to the coded graphics symbol to the image quality variation of coded graphics symbol.

Summary of the invention

The objective of the invention is provides the imaging lens of a kind of raising to coded graphics symbol image quality to the defective that the above-mentioned background technology exists.

For realizing above-mentioned purpose, the invention provides a kind of imaging lens.This imaging lens has the lens barrel of a hollow cylindrical, and this lens barrel internal fixation has five eyeglasses, from the thing side; These five eyeglasses are followed successively by first positive lens, second positive lens, the 3rd negative lens, the 4th positive lens and the 5th positive lens; First positive lens is concavo-convex positive lens, and second positive lens is protruding-straight and even lens, and the 3rd negative lens is a double-concave negative lens; The 4th positive lens is the biconvex positive lens, and the 5th positive lens is the convex-concave positive lens.

This imaging lens is provided with an aperture diaphragm between second positive lens and the 3rd negative lens,

The parameter of each lens and aperture diaphragm is following:

Wherein, r representes radius-of-curvature, and d representes the thickness of lens or the distance between the two lens adjacent surface summits, the refractive index when n is illustrated in wavelength X=632.8nm, and f representes focal length.

Because five eyeglasses of imaging lens of the present invention are positive and negative and just arrange; And first positive lens is concavo-convex positive lens; Second positive lens is protruding-straight and even lens, and the 3rd negative lens is a double-concave negative lens, and the 4th positive lens is the biconvex positive lens; The 5th positive lens is the convex-concave positive lens, thereby has improved the image quality of imaging lens of the present invention.

Description of drawings

In Figure of description:

Fig. 1 is the cut-open view of imaging lens one embodiment of the present invention;

Fig. 2 for imaging lens shown in Figure 1 when object distance is 25cm, the graph of a relation of optical transfer function degree of modulation and spatial frequency;

Fig. 3 has disclosed present embodiment imaging lens 10 when object distance is 25cm, the shape figure of each coordinate position disc of confusion on the imageing sensor;

Fig. 4 has disclosed present embodiment when object distance is 4cm, the shape figure of each coordinate position disc of confusion on the imageing sensor;

Fig. 5 has disclosed present embodiment when object distance is 35cm, the shape figure of each coordinate position disc of confusion on the imageing sensor.

Embodiment

For specifying technology contents of the present invention, architectural feature, the purpose of being reached and effect, will combine embodiment and conjunction with figs. to specify below.

See also Fig. 1, it has disclosed a specific embodiment of imaging lens of the present invention, and in the present embodiment, imaging lens 10 has the lens barrel 100 of a hollow cylindrical, and lens barrel 100 internal fixation have five full glass mirror.From the thing side, these five full glass mirror are positive and negative just to be arranged, and it is defined as first positive lens 200, second positive lens 300, the 3rd negative lens 400, the 4th positive lens 500 and the 5th positive lens 600 successively; Wherein, First positive lens 200 is concavo-convex positive lens, and second positive lens 300 is protruding-straight and even lens, and the 3rd negative lens 400 is a double-concave negative lens; The 4th positive lens 500 is the biconvex positive lens; The 5th positive lens 600 is the convex-concave positive lens, and all is coated with multilayer antireflection plated film on each surface of each lens 200,300,400,500,600, and this multilayer antireflection plated film is all band plated film.In addition, this imaging lens 10 is provided with an aperture diaphragm 700 between second positive lens 300 and the 3rd negative lens 400.

In this enforcement; The concrete Argument List of imaging lens is in table one; Wherein r representes radius-of-curvature, and d representes the thickness of lens or the distance between the two lens adjacent surface summits, the refractive index when n is illustrated in wavelength X=632.8nm; F representes focal length, N each lens surface curvature radius tolerances scope for representing with f-number.

Table one

See also Fig. 2, it has disclosed present embodiment imaging lens 10 when object distance is 25cm, images in 1/3 inch optical transfer function degree of modulation and graph of a relation of spatial frequency on the imageing sensor; Wherein, The longitudinal axis is represented the optical transfer function degree of modulation, transverse axis representation space frequency, T ₀The meridian curve of expression diffraction limit, S ₀The sagitta of arc curve of expression diffraction limit, T ₁Be illustrated in the imageing sensor coordinate (0mm, 0mm) position the meridian curve, S ₁Be illustrated in imageing sensor coordinate (0mm, the 0mm) sagitta of arc curve of position, T ₂Be illustrated in imageing sensor coordinate (0.43mm, 0.68mm) the meridian curve of position, S ₂Be illustrated in imageing sensor coordinate (0.43mm, the 0.68mm) sagitta of arc curve of position, T ₃Be illustrated in imageing sensor coordinate (0.72mm, 1.13mm) the meridian curve of position, S ₃Be illustrated in imageing sensor coordinate (0.72mm, the 1.13mm) sagitta of arc curve of position, T ₄Be illustrated in imageing sensor coordinate (1.02mm, 1.60mm) the meridian curve of position, S ₄Be illustrated in imageing sensor coordinate (1.02mm, the 1.60mm) sagitta of arc curve of position, T ₅Be illustrated in imageing sensor coordinate (1.44mm, 2.25mm) the meridian curve of position, S ₅Be illustrated in imageing sensor coordinate (1.44mm, 2.25mm) sagitta of arc curve of position.Clear this imaging lens 10 that shows can obtain the image of better quality among the figure.

See also Fig. 3, Fig. 4 and Fig. 5; It is 25cm in object distance that Fig. 3 has disclosed present embodiment imaging lens 10; When wavelength is chosen as 632.8nm, 486.0nm, 587.0nm, 660.0nm, 940.0nm; The shape figure of each image height coordinate position disc of confusion on the imageing sensor, wherein the coordinate at imageing sensor center be (0mm, 0mm); Fig. 4 is similar with Fig. 3, and it has disclosed present embodiment when object distance is 4cm, the shape figure of each image height coordinate position disc of confusion on the imageing sensor; Fig. 5 is similar with Fig. 3, and it has disclosed present embodiment when object distance is 35cm, the shape figure of each image height coordinate position disc of confusion on the imageing sensor.Fig. 3 to Fig. 5, the clear present embodiment imaging lens 10 that shows has the bigger depth of field.

The present invention is by the technical scheme of above-mentioned exposure; Can reach said purpose and effect; Yet above the exposure is merely preferred embodiment of the present invention; From not limiting interest field of the present invention with this, modify or variation as for other equivalence of the present invention, all should be encompassed in the claim scope of the present invention.

Claims

1. imaging lens; It is characterized in that: this imaging lens has the lens barrel (100) of a hollow cylindrical, and this lens barrel (100) internal fixation has five eyeglasses, from the thing side; These five eyeglasses are followed successively by first positive lens (200), second positive lens (300), the 3rd negative lens (400), the 4th positive lens (500) and the 5th positive lens (600); First positive lens (200) is concavo-convex positive lens, and second positive lens (300) is protruding-straight and even lens, and the 3rd negative lens (400) is a double-concave negative lens; The 4th positive lens (500) is the biconvex positive lens, and the 5th positive lens (600) is the convex-concave positive lens.

2. imaging lens according to claim 1 is characterized in that: this imaging lens is provided with an aperture diaphragm (700) between second positive lens (300) and the 3rd negative lens (400).

3. imaging lens according to claim 2 is characterized in that: the parameter of said each lens (200,300,400,500,600) and aperture diaphragm (700) is following:

4. imaging lens according to claim 1 is characterized in that: the aperture of said aperture diaphragm (700) more than or equal to 0.8mm smaller or equal to 1.2mm.

5. imaging lens according to claim 4 is characterized in that: the aperture of said aperture diaphragm (700) is 1.0mm.

6. imaging lens according to claim 1 is characterized in that: all be coated with multilayer antireflection plated film on each surface of said each lens (200,300,400,500,600).