CN103048767A

CN103048767A - Lens system

Info

Publication number: CN103048767A
Application number: CN2011103115041A
Authority: CN
Inventors: 柯骏程
Original assignee: Hongfujin Precision Industry Shenzhen Co Ltd; Hon Hai Precision Industry Co Ltd
Current assignee: Hongfujin Precision Industry Shenzhen Co Ltd; Hon Hai Precision Industry Co Ltd
Priority date: 2011-10-14
Filing date: 2011-10-14
Publication date: 2013-04-17
Anticipated expiration: 2031-10-14
Also published as: CN103048767B

Abstract

The invention provides a lens system. The lens system is characterized in that a first negative focal power lens, a second focal power lens, a third positive focal power lens and an imaging surface which are arranged from on object side to an image side in sequence along an optical axis; the first lens comprises a surface with an optical surface close to the image side; light rays are projected on the imaging surface through the first lens, the second lens and the third lens; the lens system meet the following conditions of Y/Z less than 1.10, G1R1/F1 less than -3.10, and G2R2/F2 more than 1.49, wherein Y and Z respectively represent distances between the end point of an optical surface and the center of the optical surface along the direction vertical to an optical axis and along the optical axis; G1R1 is the curve radius of the surface, close to the object side, of the first lens; F1 is the focal distance of the first lens, G2R2 is the curve radius of the surface, close to the object side, of the second lens, and F2 is the focal distance of the second lens.

Description

Lens system

Technical field

The present invention relates to a kind of lens system.

Background technology

Along with touch panel is widely used in the various consumption electronic products, the technology of various different contact panels also in response to and give birth to such as resistance-type, condenser type, infrared-type and surface acoustic wave type etc.

Wherein, the optical multi-touch panel of infrared-type has the simple characteristics of structure and processing procedure, and cost tool competitive edge, therefore be widely used in the part consumption electronic products.The optical multi-touch panel of infrared-type, mainly be to utilize the infrared camera module to take the picture in contact panel zone, come the motion track of interpretation input media (for example hand or pen), accurate and reaction velocity is fast because of the need interpretation, therefore required sampling image lens just need possess the characteristic of large aperture, wide viewing angle, high resolving power and high relative exposure.

Summary of the invention

In view of this, be necessary to provide the lens system of a kind of large aperture, high resolving power and high relative exposure.

A kind of lens system, along optical axis from the object side to image side direction comprise successively the first lens of a negative power, the second lens of a positive light coke, the 3rd lens and the imaging surface of a positive light coke, described first lens comprises the surface near the picture side, described surface comprises optical surface, light is by described first lens, the second lens and the 3rd lens are projecting on the described imaging surface, described lens system satisfies following condition: Y/Z＜1.10, G1R1/F1＜-3.10, G2R2/F2〉1.49, wherein, Y is along the axial distance of vertical light between the center of the end points of optical surface of described first lens and optical surface, Z is along the distance of optical axis direction between the center of the end points of optical surface of described first lens and optical surface, G1R1 is that described first lens is near the radius-of-curvature on the surface of thing side, F1 is the focal length of described first lens, G2R2 is the radius-of-curvature on the surface of the close picture of described the second lens side, and F2 is the focal length of described the second lens.

The lens system of the present embodiment is satisfying above-mentioned Y/Z＜1.10, G1R1/F1＜-3.10, G2R2/F2〉in 1.49 the situation, lens system has the performance of large light source, high resolving power and high relative exposure.

Description of drawings

Fig. 1 is the structural representation of embodiment of the invention lens system.

Fig. 2 is the spherical aberration figure of the lens system of the embodiment of the invention the first embodiment.

Fig. 3 is the curvature of field figure of the lens system of the embodiment of the invention the first embodiment.

Fig. 4 is the distortion figure of the lens system of the embodiment of the invention the first embodiment.

Fig. 5 is the relative exposure curve of the lens system of the embodiment of the invention the first embodiment.

Fig. 6 is lens system modulation transfer function (modulation transfer function, the MTF) performance diagram of the embodiment of the invention the first embodiment.

Fig. 7 is the spherical aberration figure of the lens system of the embodiment of the invention the second embodiment.

Fig. 8 is the curvature of field figure of the lens system of the embodiment of the invention the second embodiment.

Fig. 9 is the distortion figure of the lens system of the embodiment of the invention the second embodiment.

Figure 10 is the relative exposure curve of the lens system of the embodiment of the invention the second embodiment.

Figure 11 is the lens system lens system modulation transfer function performance diagram of the embodiment of the invention the second embodiment.

The main element symbol description

Lens system	10
		First lens	11
The second lens	12
		The 3rd lens	13
Infrared band pass filter	14
		Glass plate	15
Imaging surface	16
		Diaphragm	17
First surface	111
		Second surface	112
The 3rd surface	121
		The 4th surface	122
The 5th surface	131
		The 6th surface	132
The 7th surface	141
		The 8th surface	142
The 9th surface	151
		The tenth surface	152

Following embodiment further specifies the present invention in connection with above-mentioned accompanying drawing.

Embodiment

See also Fig. 1, the lens system 10 that the embodiment of the invention provides is along the optical axis from the object side to image side first lens with negative power 11, the second lens 12 with positive light coke, the diaphragm 17 that set gradually of direction, the 3rd lens 13, infrared band pass filter 14, glass plate 15 and the imaging surface 16 with positive light coke.

The material of first lens 11, the second lens 12 and the 3rd lens 13 can be selected from any in plastics, polymkeric substance and the glass, and preferably, for saving cost, first lens 11, the second lens 12 and the 3rd lens 13 all adopt plastics to make.

First lens 11, the second lens 12 and the 3rd lens 13 are non-spherical lens, and take the lens surface center as initial point, optical axis is the x axle, and first lens 11, the second lens 12 and the 3rd lens 13 each surperficial aspheric surface expression formulas are:

Figure 2011103115041100002DEST_PATH_IMAGE001

, wherein, c is the curvature at specular surface center,

Figure 2011103115041100002DEST_PATH_IMAGE002

Be the height from the optical axis to the lens surface, k is the quadric surface coefficient,

Figure 2011103115041100002DEST_PATH_IMAGE003

It is the aspheric surface coefficient on i rank.

The above-mentioned expression formula of data substitution of the table 1 by will be hereinafter, table 2, table 3, can obtain the aspherical shape of each lens surface in the lens system 10 of first embodiment of the invention, in addition, by the above-mentioned expression formula of data substitution with table 4, table 5, table 6, can know the aspherical shape of each lens surface in the lens system 10 of second embodiment of the invention.

When lens system 10 is used for imaging, light from object also passes through first lens 11, the second lens 12, the 3rd lens 13 and infrared band pass filter 14 successively from thing side direction incident lens system 10, finally converge on the imaging surface 16 by glass plate 15, by the solid imaging devices such as CCD or CMOS being arranged on imaging surface 16 places, can obtain the image of object.

First lens 11 has the first surface 111 of close thing side and near the second surface 112 as side, the radius-of-curvature of first surface 111 is denoted as G1R1, and the radius-of-curvature of second surface 112 is denoted as G1R2.Second surface 112 comprises optical surface 1121 and non-optical 1122, and non-optical 1222 around optical surface 1121.

The 3rd surface 121 and the close radius-of-curvature that looks like 122, the three surfaces 121, the 4th surface of side that the second lens 12 have close thing side are denoted as G2R1, and the radius-of-curvature on the 4th surface 122 is denoted as G2R2.

The 5th surface 131 and the close radius-of-curvature that looks like 132, the five surfaces 131, the 6th surface of side that the 3rd lens 13 have close thing side are denoted as G3R1, and the radius-of-curvature on the 6th surface 132 is denoted as G3R2.

Infrared band pass filter 14 has the 7th surface 141 of close thing side and the 8th surface 142 of close picture side.

Glass plate 15 has the 9th surface 151 of close thing side and the tenth surface 152 of close picture side.

For large aperture, high resolving power and the high relative exposure of realizing lens system 10, lens system 10 formula that satisfies condition:

（1）、Y/Z<1.10；

(2), G1R1/F1＜-3.10; And

（3）、G2R2/F2>1.49。

Wherein, Y is along the distance of vertical optical axis L direction between the center of the end points of optical surface 1121 of first lens 11 and optics section 1121, Z is along the distance of optical axis L direction between the center of the end points of optical surface 1121 of first lens 11 and optics section 1121, F1 is the focal length of first lens 11, and F2 is the focal length of the second lens 12.

Condition (1) makes lens system 10 under the condition of large aperture and wide viewing angle, can also have high relative exposure, keep when being 1.43mm such as the image height of 1.0 visual fields among Fig. 5 greater than 0.73 and Figure 10 in keep greater than 0.77 when image height is 1.43mm during 1.0 visual field.

Condition (2) diminishes the power of first lens 11, and then allows the susceptibility of lens system 10 diminish.

Condition (3) makes the power distribution of lens system 10 suitable, has the poor revisal effect of good receipts, and guarantees that lens system 10 has high-resolution image quality.

The formula in the situation that satisfy condition (1), (2) and (3), lens system 10 has large aperture, high resolving power and high relative exposure.

For further guaranteeing the image quality of lens system 10 under above-mentioned restrictive condition, first lens 11 and the 3rd lens 13 also need to satisfy following condition: G1R2/F1 〉-0.60, G1R2/F1〉G1R1/F1, G3R1/F3〉1.14, G3R2/F3＜-0.68.

Further, in order to eliminate better the aberration of lens system 10, so that energy and infrared band pass filter 14 and glass plate 15 are done compensation, first lens 11, the second lens 12 and the 3rd lens 13 also need to satisfy following condition: Vd1=Vd2=Vd3＜33, Vd1 is the Abbe number of first lens 11, Vd2 is the Abbe number of the second lens 12, and Vd3 is the Abbe number of the 3rd lens 13.

Introduce the performance of lens system 10 below in conjunction with concrete parameter.

The first embodiment (Fig. 2-Fig. 6)

The first lens 11 of lens system 10, the second lens 12, the 3rd lens 13, infrared band pass filter 14 and glass plate 15 satisfy the condition of table 1, table 2 and table 3, thereby so that the focal length of lens system 10 is 1.02mm, angle of visibility (Field Of View, FOV) be that 124.01 degree, aperture are 2.06, the unit of radius-of-curvature and thickness is mm.

Table 1

The surface	Face shape	Radius-of-curvature	Thickness	Refractive index	Abbe number
						Object plane	The plane	Infinitely great	111.8	-	-
First surface 111	Aspheric surface	5.28	1.22	1.58	29.9
						Second surface 112	Aspheric surface	0.73	1.67	-	-
The 3rd surface 121	Aspheric surface	2.02	0.67	1.58	29.9
						The 4th surface 122	Aspheric surface	15.92	0.72	-	-
Diaphragm 17	The plane	Infinitely great	0.33	-	-
						The 5th surface 131	Aspheric surface	2.88	1.20	1.58	29.9
The 6th surface 132	Aspheric surface	-1.53	0.20	-	-
						The 7th surface 141	The plane	Infinitely great	0.30	1.52	64.2
The 8th surface 142	The plane	Infinitely great	1.16	-	-
						The 9th surface 151	The plane	Infinitely great	0.40	1.52	64.2
The tenth surface 152	The plane	Infinitely great	0.10	-	-
						Imaging surface 16	The plane	Infinitely great	-	-	-

Table 2

The surface	A4	A6	A8	K
					First surface 111	-0.0086	0.00035	-0.000008	0
Second surface 112	0.0164	-0.0032	-0.0064	-0.9264
					The 3rd surface 121	0.0397	-0.0149	-	-4.1959
The 4th surface 122	0.0303	-0.0124	0.0072	-1032.5270
					The 5th surface 131	0.0588	-0.0456	0.0103	-20.0887
The 6th surface 132	-0.0054	0.0157	-0.0101	-2.2499

Table 3

Z	Y	F1	F2
				1.42mm	1.41mm	-1.65mm	4.00mm

As seen from Figure 2, when lens system 10 was 840 nanometers, 850 nanometers and 860 nanometers (shown in curve a, b, the c) at wavelength, the image planes spherical aberration all was controlled in (0.05mm, 0.05mm) scope.Found out by Fig. 3, the meridianal curvature of field value of the curvature of field and Sagittal field curvature value all are controlled in (0.1mm, 0.1mm) scope.Learnt by Fig. 4, aberration control is in (20%, 20%) scope.This shows, the aberration of lens system 10, the curvature of field, distortion can both well be proofreaied and correct.

As shown in Figure 6, the 168lp/mm(line right/millimeter) nyquist frequency (Nyquist Frequency) condition under, the MTF(Modulation Transfer Function of visual field, center, modulation transfer function)〉0.6(comprises the sagitta of arc direction of S-Sagittal and the meridian direction of T-Tangential) (shown in the curve A), the MTF of 0.8 visual field, corner〉0.48(comprises S and T direction) (curve C, shown in the E), 0.48＜MTF between visual field, center and 0.8 visual field, corner＜0.6(curve B, shown in the D), the MTF of 1.0 visual fields〉0.43(curve F, shown in the G).

The second embodiment (Fig. 7-Figure 11)

The first lens 11 of lens system 10, the second lens 12, the 3rd lens 13, infrared band pass filter 14 and glass plate 15 satisfy the condition of table 4, table 5 and table 6, thereby so that the focal length of lens system 10 is 1.04mm, angle of visibility is 123.96 degree, aperture is 2.07, the unit of radius-of-curvature and thickness is mm.

Table 4

The surface	Face shape	Radius-of-curvature	Thickness	Refractive index	Abbe number
						Object plane	The plane	Infinitely great	-111.8	-	-
First surface 111	Aspheric surface	9.95	1.40	1.58	29.9
						Second surface 112	Aspheric surface	0.83	1.77	-	-
The 3rd surface 121	Aspheric surface	1.73	0.66	1.58	29.9
						The 4th surface 122	Aspheric surface	6.34	0.61	-	-
Diaphragm 17	The plane	Infinitely great	0.33	-	-
						The 5th surface 131	Aspheric surface	2.47	1.08	1.58	29.9
The 6th surface 132	Aspheric surface	-1.75	0.20	-	-
						The 7th surface 141	The plane	Infinitely great	0.30	1.52	64.2
The 8th surface 142	The plane	Infinitely great	0.15	-	-
						The 9th surface 151	The plane	Infinitely great	0.40	1.52	64.2
The tenth surface 152	The plane	Infinitely great	0.10	-	-
						Imaging surface 16	The plane	Infinitely great	-	-	-

Table 5

The surface	A4	A6	A8	K
					First surface 111	-0.001	0.000014	-0.00000071	0
Second surface 112	0.2127	-0.0522	0.0199	-1.7560
					The 3rd surface 121	-0.009	0.0049	-	-0.5929
The 4th surface 122	-0.0052	0.0101	-0.0065	27.8397
					The 5th surface 131	0.0677	-0.0345	0.0035	-13.4168
The 6th surface 132	-0.0445	0.0540	-0.0213	-4.9394

Table 6

Z	Y	F1	F2
				1.38mm	1.34mm	-1.69mm	3.97mm

As seen from Figure 7, when lens system 10 was 840 nanometers, 850 nanometers and 860 nanometers (shown in curve a, b, the c) at wavelength, the image planes spherical aberration all was controlled in (0.05mm, 0.05mm) scope.Can be learnt by Fig. 8, the meridianal curvature of field value of the curvature of field and Sagittal field curvature value all are controlled in (0.1mm, 0.1mm) scope.Found out by Fig. 9, aberration control is in (20%, 20%) scope.This shows, the aberration of lens system 10, the curvature of field, distortion can both well be proofreaied and correct.

As shown in Figure 11.Under the nyquist frequency condition of 168lp/mm, the MTF of visual field, center〉shown in the 0.6(curve A), the MTF of 0.8 visual field, corner〉shown in the 0.48(curve C, E), shown in 0.48＜MTF between visual field, center and 0.8 visual field, corner＜0.6(curve B, the D), the MTF of 1.0 visual fields〉shown in 0.34(curve F, the G).

Be understandable that, those skilled in the art also can do other variation etc. and be used in design of the present invention in spirit of the present invention, as long as it does not depart from technique effect of the present invention and all can.The variation that these are done according to spirit of the present invention all should be included within the present invention's scope required for protection.

Claims

1. lens system, along optical axis from the object side to image side direction comprise successively the first lens of a negative power, the second lens of a positive light coke, the 3rd lens and the imaging surface of a positive light coke, described first lens comprises the surface near the picture side, described surface comprises optical surface, light is by described first lens, the second lens and the 3rd lens are projecting on the described imaging surface, it is characterized in that, described lens system satisfies following condition: Y/Z＜1.10, G1R1/F1＜-3.10, G2R2/F2〉1.49, wherein, Y is along the axial distance of vertical light between the center of the end points of optical surface of described first lens and optical surface, Z is along the distance of optical axis direction between the center of the end points of optical surface of described first lens and optical surface, G1R1 is that described first lens is near the radius-of-curvature on the surface of thing side, F1 is the focal length of described first lens, and G2R2 is the radius-of-curvature on the surface of the close picture of described the second lens side, and F2 is the focal length of described the second lens.

2. lens system as claimed in claim 1 is characterized in that, the described first lens formula G1R2/F1 that satisfies condition 〉-0.60, G1R2/F1〉G1R1/F1, G1R2 is that described first lens is near the radius-of-curvature on the surface of picture side.

3. lens system as claimed in claim 2, it is characterized in that described the 3rd lens formula G3R1/F3 that satisfies condition〉1.14, G3R2/F3＜-0.68, G3R1 is the radius-of-curvature on the surface of the close thing side of described the 3rd lens, and G3R2 is that described the 3rd lens are near the radius-of-curvature on the surface of picture side.

4. lens system as claimed in claim 3, it is characterized in that, described first lens, the second lens and the 3rd lens satisfy Vd1=Vd2=Vd3＜33, and Vd1 is the Abbe number of described first lens, Vd2 is the Abbe number of described the second lens, and Vd3 is the Abbe number of described the 3rd lens.

5. lens system as claimed in claim 4 is characterized in that, described first lens, the second lens and the 3rd lens are non-spherical lens.

6. lens system as claimed in claim 1 is characterized in that, described lens system further comprises a infrared band pass filter between described the 3rd lens and imaging surface.

7. lens system as claimed in claim 6 is characterized in that, is provided with a glass sheet between described infrared band pass filter and the imaging surface to protect described imaging surface.

8. lens system as claimed in claim 1 is characterized in that, Y is 1.41mm, and Z is 1.42mm, and F1 is-1.65mm that F2 is 4.00mm.

9. lens system as claimed in claim 1 is characterized in that, Y is 1.34mm, and Z is 1.38mm, and F1 is-1.69mm that F2 is 3.97mm.