# Patent

## Title
Six-piece optical lens system

## Abstract

A six-piece optical lens system includes, in order from the object side to the image side: a first lens element with a negative refractive power has a concave image-side surface, a second lens element with a positive refractive power has a convex image-side surface, a third lens element with a positive refractive power has a convex object-side surface, a fourth lens element with a negative refractive power has a concave image-side surface, a fifth lens element with a positive refractive power has a convex object-side surface, and a sixth lens element with a negative refractive power has a concave image-side surface. Each of the first, second, fourth and sixth lens elements has at least one aspheric surface, and one of the third and fifth lens elements is made of glass. Thereby, such a system can be applied to a high resolution mobile phone.

## Background
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical lens system, and more particularly to a six-piece optical lens system.
2. Description of the Prior Art
A carrier provided with an optical lens system has become the trend of modern electronic products, and its functions of taking photographs or recording videos can not only increase the additional value of the products but also can get young people's attention. With the development of consumption habits, this trend is the gradual rise in other electronic carrier products, so many kinds of portable products are provided with a lens system, such as, digital camera, mobile phone, NB, game machine, Webcam and so on. However, such products have some limitations, that is, the inner space of the electronic carrier is largely compressed since it has become smaller in size, so the length of the lens system which is disposed on the carrier is limited.
In addition, due to the fierce competition in industry and low profit, the electronic carrier with a higher resolution optical lens system has become the main marketing requirement, that is, the optical lens system should not only reduce the manufacturing and material costs but also provide a wide field of view and big stop.
Current optical lens systems with a wide field of view mostly consist of five lens elements, including one gluing lens element, however, such a design can not meet the requirements of light, thin, short and small, and can not reduce the cost, weight, volume and thickness of the optical lens system.
The present invention mitigates and/or obviates the aforementioned disadvantages.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide a six-piece optical lens system without having an excessively long total track length, the six-piece optical lens system not only can be applied to a high resolution mobile phone, but also has a wide field of view, big stop, high pixel, high resolution and low height.
A six-piece optical lens system in accordance with the present invention comprises, in order from the object side to the image side: a first lens element with a negative refractive power having a concave image-side, at least one of an object-side and the image-side surfaces of the first lens element being aspheric; a second lens element with a positive refractive power having a convex image-side surface, at least one of an object-side and the image-side surfaces of the second lens element being aspheric; a third lens element with a positive refractive power having a convex object-side surface; a fourth lens element with a negative refractive power having a concave image-side surface, at least one of an object-side and the image-side surfaces of the fourth lens element being aspheric; a fifth lens element with a positive refractive power having a convex object-side surface; and a sixth lens element with a negative refractive power having a concave image-side, at least one of an object-side and the image-side surfaces of the sixth lens element being aspheric. One of the third lens element and the fifth lens element is made of glass.
The present six-piece optical lens system further comprises a stop which is located between the first lens element and the second lens element.
The present six-piece optical lens system further comprises a stop which is located between the second lens element and the third lens element.
According to one aspect of the present six-piece optical lens system, the focal length of the first lens element is f1, the focal length of the third lens element is f3, and they satisfy the relation: 0.6<|f1|/|f3|<2.0. If |f1|/|f3| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, If |f1|/|f3| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low.
According to one aspect of the present six-piece optical lens system, the focal length of the third lens element is f3, the focal length of the fourth lens element is f4, and they satisfy the relation: 0.5<|f3|/|f4|<1.8. If |f3|/|f4| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f3|/|f4| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low.
According to one aspect of the present six-piece optical lens system, the focal length of the fourth lens element is f4, the focal length of the fifth lens element is f5, and they satisfy the relation: 0.4<|f4|/|f5|<1.2. If |f4|/|f5| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f4|/|f5| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low.
According to another aspect of the present six-piece optical lens system, the focal length of the first lens element, the second lens element and the third lens element combined is f123, the focal length of the six-piece optical lens system is f, and they satisfy the relation: 0.5<|f123|/|f|<1.0. If |f123|/|f| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f123|/|f| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low.
According to another aspect of the present six-piece optical lens system, the focal length of the fourth lens element, the fifth lens element and the sixth lens element combined is f456, the focal length of the six-piece optical lens system is f, and they satisfy the relation: 2.5<|f456|/|f|<4.8. If |f456|/|f| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f456|/|f| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low.
According to another aspect of the present six-piece optical lens system, the focal length of the first lens element is f1, the focal length of the second lens element and the third lens element combined is f23, and they satisfy the relation: 1.4<|f1|/|f23|<2.1. If |f1|/|f23| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f1|/|f23| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low.
According to another aspect of the present six-piece optical lens system, the focal length of the second lens element and the third lens element combined is f23, the focal length of the fourth lens element and the fifth lens element combined is f45, and they satisfy the relation: |f23|/|f45|<0.3. If |f23|/|f45| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f23|/|f45| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low.
According to another aspect of the present six-piece optical lens system, the focal length of the second lens element and the third lens element combined is f23, the focal length of the fifth lens element and the sixth lens element combined is f56, and they satisfy the relation: 0.3<|f23|/|f56|<0.8. If |f23|/|f56| satisfies the above relation, a wide field of view, big stop, high pixel and low height can be provided and the resolution can be improved evidently. Contrarily, if |f23|/|f56| exceeds the above range, the performance and resolution of the optical lens system will be reduced, and the yield rate will be low.
According to another aspect of the present six-piece optical lens system, the focal length of the six-piece optical lens system is f, the distance from the object-side surface of the first lens element to the image plane along the optical axis is TL, and they satisfy the relation: |f/TL|<0.5. If |f/TL| satisfies the above relation, the total track length of the optical lens system can be relatively short, and the requirement of miniaturization can be satisfied.
According to another aspect of the present six-piece optical lens system, the first lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the first lens element are aspheric. The second lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the second lens element are aspheric. The third lens element is made of plastic and has a convex image-side surface, and the object-side surface and the image-side surface of the third lens element are aspheric. The fourth lens element is made of plastic and has a concave object-side surface, and the object-side surface and the image-side surface of the fourth lens element are aspheric. The fifth lens element is made of glass and has a convex image-side surface, and the object-side surface and the image-side surface of the fifth lens element are aspheric. The sixth lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the sixth lens element are aspheric.
According to another aspect of the present six-piece optical lens system, the first lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the first lens element are aspheric. The second lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the second lens element are aspheric. The third lens element is made of glass and has a convex image-side surface, and the object-side surface and the image-side surface of the third lens element are aspheric. The fourth lens element is made of plastic and has a concave object-side surface, and the object-side surface and the image-side surface of the fourth lens element are aspheric. The fifth lens element is made of plastic and has a convex image-side surface, and the object-side surface and the image-side surface of the fifth lens element are aspheric. The sixth lens element is made of plastic and has a convex object-side surface, and the object-side surface and the image-side surface of the sixth lens element are aspheric.
The present invention will be presented in further details from the following descriptions with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiments in accordance with the present invention.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A shows an optical lens system in accordance with a first embodiment of the present invention;
FIG. 1B shows the longitudinal spherical aberration curve, the astigmatic field curve, and the distortion curve of the first embodiment of the present invention;
FIG. 2A shows an optical lens system in accordance with a second embodiment of the present invention;
FIG. 2B shows the longitudinal spherical aberration curve, the astigmatic field curve, and the distortion curve of the second embodiment of the present invention;



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1A, which shows a six-piece optical lens system in accordance with a first embodiment of the present invention, and FIG. 1B shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the first embodiment of the present invention. A six-piece optical lens system in accordance with the first embodiment of the present invention comprises, in order from the object side to the image side:
A first lens element 110 with a negative refractive power made of plastic has a convex object-side surface 111 and a concave image-side surface 112, and the object-side surface 111 and the image-side surface 112 of the first lens element 110 are aspheric.
A second lens element 120 with a positive refractive power made of plastic has a convex object-side surface 121 and a convex image-side surface 122, and the object-side surface 121 and the image-side surface 122 of the second lens element 120 are aspheric.
A stop 100.
A third lens element 130 with a positive refractive power made of plastic has a convex object-side surface 131 and a convex image-side surface 132, and the object-side surface 131 and the image-side surface 132 of the third lens element 130 are aspheric.
A fourth lens element 140 with a negative refractive power made of plastic has a concave object-side surface 141 and a concave image-side surface 142, and the object-side surface 141 and the image-side surface 142 of the fourth lens element 140 are aspheric.
A fifth lens element 150 with a positive refractive power made of glass has a convex object-side surface 151 and a convex image-side surface 152, and the object-side surface 151 and the image-side surface 152 of the fifth lens element 150 are aspheric.
A sixth lens element 160 with a negative refractive power made of plastic has a convex object-side surface 161 and a concave image-side surface 162, and the object-side surface 161 and the image-side surface 162 of the sixth lens element 160 are aspheric.
An IR cut filter 170 made of glass is located between the image-side surface 162 of the sixth lens element 160 and an image plane 180 and has no influence on the focal length of the six-piece optical lens system.
The equation for the aspheric surface profiles of the first embodiment is expressed as follows:




  z
  =
  
    
      
        ch
        2
      
      
        1
        +
        
          
            [
            
              1
              -
              
                
                  (
                  
                    k
                    +
                    1
                  
                  )
                
                ⁢
                
                  c
                  2
                
                ⁢
                
                  h
                  2
                
              
            
            ]
          
          0.5
        
      
    
    +
    
      Ah
      4
    
    +
    
      Bh
      6
    
    +
    
      Ch
      8
    
    +
    
      Dh
      10
    
    +
    
      Eh
      12
    
    +
    
      Gh
      14
    
    +
    ...
  




wherein:
z represents the value of a reference position with respect to a vertex of the surface of a lens and a position with a height h along the optical axis 190;
k represents the conic constant;
c represents the reciprocal of the radius of curvature;
A, B, C, D, E, G, . . . : represent the high-order aspheric coefficients.
In the first embodiment of the present six-piece optical lens system, the focal length of the six-piece optical lens system is f, and it satisfies the relation:

f=4.27.

In the first embodiment of the present six-piece optical lens system, the f-number of the six-piece optical lens system is Fno, and it satisfies the relation:

Fno=2.6.

In the first embodiment of the present six-piece optical lens system, the field of view of the six-piece optical lens system is 2ω, and it satisfies the relation:

2ω=70°.

In the first embodiment of the present six-piece optical lens system, the focal length of the first lens element 110 is f1, the focal length of the third lens element 130 is f3, and they satisfy the relation:

|f1|/|f3|=1.656.

In the first embodiment of the present six-piece optical lens system, the focal length of the third lens element 130 is f3, the focal length of the fourth lens element 140 is f4, and they satisfy the relation:

|f3|/|f4|=0.774.

In the first embodiment of the present six-piece optical lens system, the focal length of the fourth lens element 140 is f4, the focal length of the fifth lens element 150 is f5, and they satisfy the relation:

|f4|/|f5|=0.923.

In the first embodiment of the present six-piece optical lens system, the focal length of the first lens element 110, the second lens element 120 and the third lens element 130 combined is f123, the focal length of the six-piece optical lens system is f, and they satisfy the relation:

|f123|/|f|=0.769.

In the first embodiment of the present six-piece optical lens system, the focal length of the fourth lens element 140, the fifth lens element 150 and the sixth lens element 160 combined is f456, the focal length of the six-piece optical lens system is f, and they satisfy the relation:

|f456|/|f|=2.974.

In the first embodiment of the present six-piece optical lens system, the focal length of the first lens element 110 is f1, the focal length of the second lens element 120 and the third lens element 130 combined is f23, and they satisfy the relation:

|f1|/|f23|=1.807.

In the first embodiment of the present six-piece optical lens system, the focal length of the second lens element 120 and the third lens element 130 combined is f23, the focal length of the fourth lens element 140 and the fifth lens element 150 combined is f45, and they satisfy the relation:

|f23|/|f45|=0.138.

In the first embodiment of the present six-piece optical lens system, the focal length of the second lens element 120 and the third lens element 130 combined is f23, the focal length of the fifth lens element 150 and the sixth lens element 160 combined is f56, and they satisfy the relation:

|f23|/|f56|=0.489.

In the first embodiment of the present six-piece optical lens system, the focal length of the six-piece optical lens system is f, the distance from the object-side surface 111 of the first lens element 110 to the image plane 180 along the optical axis 190 is TL, and they satisfy the relation:

|f/TL|=0.266.

The detailed optical data of the first embodiment is shown in table 1, and the aspheric surface data is shown in table 2, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm. In the tables 1 and 2, the surfaces 1 and 2 represent the object-side surface 111 and the image-side surface 112 of the first lens element 110, respectively, the surfaces 3 and 4 represent the object-side surface 121 and the image-side surface 122 of the second lens element 120, respectively, the surfaces 6 and 7 represent the object-side surface 131 and the image-side surface 132 of the third lens element 130, respectively, the surfaces 8 and 9 represent the object-side surface 141 and the image-side surface 142 of the fourth lens element 140, respectively, and the surfaces 12 and 13 represent the object-side surface 161 and the image-side surface 162 of the sixth lens element 160, respectively.







TABLE 1







(Embodiment 1)


f(focal length) = 4.27 mm, Fno = 2.6, 2ω = 70°.













Surface

Curvature Radius
Thickness
Material
nd
vd
















0
Object
Infinity
Infinity





1
Lens 1
2.390466(ASP)
0.424625
Plastic
1.535
56


2

0.94691(ASP)
1.173357


3
Lens 2
27.13449(ASP)
0.760859
Plastic
1.634
23.9


4

−10.2075(ASP)
0.077425


5
Stop
Infinity
0.203418


6
Lens 3
3.146663(ASP)
1.014048
Plastic
1.535
56


7

−1.40964(ASP)
0.066544


8
Lens 4
−14.2314(ASP)
0.465062
Plastic
1.634
23.9


9

1.861593(ASP)
0.175693


10
Lens 5
4.452003
1.470815
Glass
1.7292
54.6735


11

−3.16638
0.484929


12
Lens 6
6.571901(ASP)
0.641133
Plastic
1.634
23.9


13

2.079743(ASP)
0.286166


14
IR-filter
Infinity
0.3
Glass
1.5168
64.16734


15

Infinity
0.4565


16
Image
Infinity
















TABLE 2





Aspheric Coefficients

















Surface













1
2
3
4
6





K =
−1.21007
−0.69271
−103.802
78.08349
−13.0111


A =
0.002574
0.06573
−0.02283
0.003542
0.143772


B =
−0.00141
−0.00836
−0.01706
−0.09798
−0.41986


C =
−7.4E−05
0.021619
0.021042
0.210496
0.55819


D =
5.84E−06
−0.00085
−0.00407
−0.11702
−0.28189












Surface













7
8
9
12
13





K =
−1.88673
139.7694
−7.91724
−148.079
−10.0119


A =
0.029929
−0.04391
0.020106
−0.08092
−0.03892


B =
−0.11385
−0.02956
−0.01036
−0.00202
0.002968


C =
0.070151
0.032348
0.004507
0.001816
−0.00038


D =
−0.00588
−0.00586
−0.00094
−0.00049
1.98E−05









Referring to FIG. 2A, which shows a six-piece optical lens system in accordance with a second embodiment of the present invention, and FIG. 2B shows the longitudinal spherical aberration curves, the astigmatic field curves, and the distortion curve of the second embodiment of the present invention. A six-piece optical lens system in accordance with the second embodiment of the present invention comprises, in order from the object side to the image side:
A first lens element 210 with a negative refractive power made of plastic has a convex object-side surface 211 and a concave image-side surface 212, and the object-side surface 211 and the image-side surface 212 of the first lens element 210 are aspheric.
A stop 200.
A second lens element 220 with a positive refractive power made of plastic has a convex object-side surface 221 and a convex image-side surface 222, and the object-side surface 221 and the image-side surface 222 of the second lens element 220 are aspheric.
A third lens element 230 with a positive refractive power made of glass has a convex object-side surface 231 and a convex image-side surface 232, and the object-side surface 231 and the image-side surface 232 of the third lens element 230 are aspheric.
A fourth lens element 240 with a negative refractive power made of plastic has a concave object-side surface 241 and a concave image-side surface 242, and the object-side surface 241 and the image-side surface 242 of the fourth lens element 240 are aspheric.
A fifth lens element 250 with a positive refractive power made of plastic has a convex object-side surface 251 and a convex image-side surface 252, and the object-side surface 251 and the image-side surface 252 of the fifth lens element 250 are aspheric.
A sixth lens element 260 with a negative refractive power made of plastic has a convex object-side surface 261 and a concave image-side surface 262, and the object-side surface 261 and the image-side surface 262 of the sixth lens element 260 are aspheric.
An IR cut filter 270 made of glass is located between the image-side surface 262 of the fifth lens element 260 and an image plane 280 and has no influence on the focal length of the six-piece optical lens system.
The equation for the aspheric surface profiles of the second embodiment is expressed as follows:




  z
  =
  
    
      
        ch
        2
      
      
        1
        +
        
          
            [
            
              1
              -
              
                
                  (
                  
                    k
                    +
                    1
                  
                  )
                
                ⁢
                
                  c
                  2
                
                ⁢
                
                  h
                  2
                
              
            
            ]
          
          0.5
        
      
    
    +
    
      Ah
      4
    
    +
    
      Bh
      6
    
    +
    
      Ch
      8
    
    +
    
      Dh
      10
    
    +
    
      Eh
      12
    
    +
    
      Gh
      14
    
    +
    ...
  




wherein:
z represents the value of a reference position with respect to a vertex of the surface of a lens and a position with a height h along the optical axis 290;
k represents the conic constant;
c represents the reciprocal of the radius of curvature;
A, B, C, D, E, G, . . . : represent the high-order aspheric coefficients.
In the second embodiment of the present six-piece optical lens system, the focal length of the six-piece optical lens system is f, and it satisfies the relation:

f=3.9.

In the second embodiment of the present six-piece optical lens system, the f-number of the six-piece optical lens system is Fno, and it satisfies the relation:

Fno=2.4.

In the second embodiment of the present six-piece optical lens system, the field of view of the six-piece optical lens system is 2ω, and it satisfies the relation:

2ω=74°.

In the second embodiment of the present six-piece optical lens system, the focal length of the first lens element 210 is f1, the focal length of the third lens element 230 is f3, and they satisfy the relation:

|f1|/|f3|=0.977.

In the second embodiment of the present six-piece optical lens system, the focal length of the third lens element 230 is f3, the focal length of the fourth lens element 240 is f4, and they satisfy the relation:

|f3|/|f4|=1.545.

In the second embodiment of the present six-piece optical lens system, the focal length of the fourth lens element 240 is f4, the focal length of the fifth lens element 250 is f5, and they satisfy the relation:

|f4|/|f5|=0.668.

In the second embodiment of the present six-piece optical lens system, the focal length of the first lens element 210, the second lens element 220 and the third lens element 230 combined is f123, the focal length of the six-piece optical lens system is f, and they satisfy the relation:

|f123|/|f|=0.719.

In the second embodiment of the present six-piece optical lens system, the focal length of the fourth lens element 240, the fifth lens element 250 and the sixth lens element 260 combined is f456, the focal length of the six-piece optical lens system is f, and they satisfy the relation:

|f456|/|f|=4.353.

In the second embodiment of the present six-piece optical lens system, the focal length of the first lens element 210 is f1, the focal length of the second lens element 220 and the third lens element 230 combined is f23, and they satisfy the relation:

|f1|/|f23|=1.703.

In the second embodiment of the present six-piece optical lens system, the focal length of the second lens element 220 and the third lens element 230 combined is f23, the focal length of the fourth lens element 240 and the fifth lens element 250 combined is f45, and they satisfy the relation:

|f23|/|f45|=0.079.

In the second embodiment of the present six-piece optical lens system, the focal length of the second lens element 220 and the third lens element 230 combined is f23, the focal length of the fifth lens element 250 and the sixth lens element 260 combined is f56, and they satisfy the relation:

|f23|/|f56|=0.604.

In the second embodiment of the present six-piece optical lens system, the focal length of the six-piece optical lens system is f, the distance from the object-side surface 211 of the first lens element 210 to the image plane 280 along the optical axis 290 is TL, and they satisfy the relation:

|f/TL|=0.266.

The detailed optical data of the second embodiment is shown in table 3, and the aspheric surface data is shown in table 4, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm. In the tables 3 and 4, the surfaces 1 and 2 represent the object-side surface 211 and the image-side surface 212 of the first lens element 210, respectively, the surfaces 4 and 5 represent the object-side surface 221 and the image-side surface 222 of the second lens element 220, respectively, the surfaces 8 and 9 represent the object-side surface 241 and the image-side surface 242 of the fourth lens element 240, respectively, the surfaces 10 and 11 represent the object-side surface 251 and the image-side surface 252 of the fifth lens element 250, respectively, and the surfaces 12 and 13 represent the object-side surface 261 and the image-side surface 262 of the sixth lens element 260, respectively.







TABLE 3







(Embodiment 2)


f(focal length) = 3.9 mm, Fno = 2.4, 2ω = 74°.













Sur-

Curvature






face

Radius
Thickness
Material
nd
vd
















0
Object
Infinity
Infinity





1
Lens 1
4.33095(ASP)
0.399254
Plastic
1.535
56


2

1.147043(ASP)
1.436016


3
Stop
Infinity
0.047929


4
Lens 2
24.43088(ASP)
0.72482
Plastic
1.535
56


5

−1.73003(ASP)
0.205304


6
Lens 3
6.533319
1.312139
Glass
1.6204
60.3439


7

−2.54141
0.144328


8
Lens 4
−2.25137(ASP)
0.502847
Plastic
1.634
23.9


9

3.291223(ASP)
0.059682


10
Lens 5
3.581905(ASP)
1.224091
Plastic
1.535
56


11

−2.59942(ASP)
0.140857


12
Lens 6
1.350809(ASP)
0.398828
Plastic
1.535
56


13

1.094418(ASP)
1.021131


14
IR-filter
Infinity
0.3
Glass
1.5168
64.1674


15

Infinity
0.037


16
Image
Infinity
















TABLE 4





Aspheric Coefficients

















Surface













1
2
4
5
8





K =
3.484695
−0.02167
900.0333
1.329657
0.098966


A =
0.040739
0.106388
0.096257
0.04289
−0.00291


B =
−0.02152
−0.0346
−0.51833
−0.079
0.003155


C =
0.003529
0.020722
0.652999
0.070671
0.000598


D =
−0.0004
−0.008
−0.45356
−0.0355
0.000187












Surface













9
10
11
12
13





K =
−11.7226
−0.12739
−1.47663
−0.87401
−0.86495


A =
0.013874
−0.00084
0.014088
−0.1092
−0.15306


B =
−0.00099
−0.00136
0.004058
−0.0025
0.021411


C =
0.000285
7.03E−04
1.51E−04
0.002312
−0.00236


D =
5.15E−05
−1.12E−04
−6.74E−05
−1.17E−04
8.67E−05



















TABLE 5







Embodiment 1
Embodiment 2




















f
4.27
3.9



Fno
2.6
2.4



2ω
70
74



|f1|/|f3|
1.656
0.977



|f3|/|f4|
0.774
1.545



|f4|/|f5|
0.923
0.668



|f123|/|f|
0.769
0.719



|f456|/|f|
2.974
4.353



|f1|/|f23|
1.807
1.703



|f23|/|f45|
0.138
0.079



|f23|/|f56|
0.489
0.604



|f/TL|
0.266
0.266










It is to be noted that the tables 1-4 show different data from the different embodiments, however, the data of the different embodiments is obtained from experiments. Therefore, any product of the same structure is deemed to be within the scope of the present invention even if it uses different data. Table 5 lists the relevant data for the various embodiments of the present invention.
In the present six-piece optical lens system, if the object-side or the image-side surface of the lens elements is convex, the object-side or the image-side surface of the lens elements in proximity of the optical axis is convex. If the object-side or the image-side surface of the lens elements is concave, the object-side or the image-side surface of the lens elements in proximity of the optical axis is concave.
While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.

## Claims

1. A six-piece optical lens system comprising, in order from an object side to an image side:
a first lens element with a negative refractive power having a concave image-side surface, at least one of an object-side and the image-side surfaces of the first lens element being aspheric;
a second lens element with a positive refractive power having a convex image-side surface, at least one of an object-side and the image-side surfaces of the second lens element being aspheric;
a third lens element with a positive refractive power having a convex object-side surface;
a fourth lens element with a negative refractive power having a concave image-side surface, at least one of an object-side and the image-side surfaces of the fourth lens element being aspheric;
a fifth lens element with a positive refractive power having a convex object-side surface;
a sixth lens element with a negative refractive power having a concave image-side surface, at least one of an object-side and the image-side surfaces of the sixth lens element being aspheric; and
one of the third lens element and the fifth lens element being made of glass;
wherein a focal length of the first lens element is f1, a focal length of the second lens element and the third lens element combined is f23, and they satisfy the relation:


1.4<|f1|/|f23|<2.1.

2. The six-piece optical lens system as claimed in claim 1 further comprising a stop which is located between the first lens element and the second lens element.

3. The six-piece optical lens system as claimed in claim 1 further comprising a stop which is located between the second lens element and the third lens element.

4. The six-piece optical lens system as claimed in claim 1, wherein the focal length of the first lens element is f1, a focal length of the third lens element is f3, and they satisfy the relation:


0.6<|f1|/|f3|<2.0.

5. The six-piece optical lens system as claimed in claim 1, wherein a focal length of the third lens element is f3, a focal length of the fourth lens element is f4, and they satisfy the relation:


0.5<|f3|/|f4|<1.8.

6. The six-piece optical lens system as claimed in claim 1, wherein a focal length of the fourth lens element is f4, a focal length of the fifth lens element is f5, and they satisfy the relation:


0.4<|f4|/|f5|<1.2.

7. The six-piece optical lens system as claimed in claim 1, wherein a focal length of the first lens element, the second lens element and the third lens element combined is f123, a focal length of the six-piece optical lens system is f, and they satisfy the relation:


0.5<|f123|/|f|<1.0.

8. The six-piece optical lens system as claimed in claim 1, wherein a focal length of the fourth lens element, the fifth lens element and the sixth lens element combined is f456, a focal length of the six-piece optical lens system is f, and they satisfy the relation:


2.5<|f456|/|f|<4.8.

9. The six-piece optical lens system as claimed in claim 1, wherein the focal length of the second lens element and the third lens element combined is f23, a focal length of the fourth lens element and the fifth lens element combined is f45, and they satisfy the relation:


|f23|/|f45|<0.3.

10. The six-piece optical lens system as claimed in claim 1, wherein the focal length of the second lens element and the third lens element combined is f23, a focal length of the fifth lens element and the sixth lens element combined is f56, and they satisfy the relation:


0.3<|f23|/|f56|<0.8.

11. The six-piece optical lens system as claimed in claim 1, wherein a focal length of the six-piece optical lens system is f, a distance from the object-side surface of the first lens element to an image plane along an optical axis is TL, and they satisfy the relation:


|f/TL|<0.5.

12. The six-piece optical lens system as claimed in claim 1, wherein the first, second, third, fourth, and sixth lens elements are made of plastic, the fifth lens element is made of glass, the object-side surface of the first lens element is convex, the object-side surface and the image-side surface of the first lens element are aspheric, the object-side surface of the second lens element is convex, the object-side surface and the image-side surface of the second lens element are aspheric, the image-side surface of the third lens element is convex, the object-side surface and the image-side surface of the third lens element are aspheric, the object-side surface of the fourth lens element is concave, the object-side surface and the image-side surface of the fourth lens element are aspheric, the image-side surface of the fifth lens element is convex, the object-side surface and the image-side surface of the fifth lens element are aspheric, the object-side surface of the sixth lens element is convex, and the object-side surface and the image-side surface of the sixth lens element are aspheric.

13. The six-piece optical lens system as claimed in claim 1, wherein the first, second, fourth, fifth and sixth lens elements are made of plastic, the third lens element is made of glass, the object-side surface of the first lens element is convex, the object-side surface and the image-side surface of the first lens element are aspheric, the object-side surface of the second lens element is convex, the object-side surface and the image-side surface of the second lens element are aspheric, the image-side surface of the third lens element is convex, the object-side surface and the image-side surface of the third lens element are aspheric, the object-side surface of the fourth lens element is concave, the object-side surface and the image-side surface of the fourth lens element are aspheric, the image-side surface of the fifth lens element is convex, the object-side surface and the image-side surface of the fifth lens element are aspheric, the object-side surface of the sixth lens element is convex, and the object-side surface and the image-side surface of the sixth lens element are aspheric.