Lens module and image apparatus

Abstract

A lens module for capturing an object light-beam from an object-side is provided. The lens module includes a first lens group, a second lens group, a third lens group, a fourth lens group and a fifth lens group sequentially-arranged from the object-side to an image-side. The five lens groups respectively have at least one lens with positive refractive-power and at least one lens with negative refractive-power. The first, third and fifth lens groups are fixed groups, while the second and fourth lens groups are movable groups. An image apparatus including the lens module is also provided.

What is claimed is: 
     
         1 . A lens, having an object-side and an image-side for capturing an object light-beam from the object-side, the lens disposed on a transmission path of the object light-beam and comprising five lens groups:
 a first lens group with positive refractive-power;   a second lens group with negative refractive-power;   a third lens group with positive refractive-power, wherein the third lens group comprises a cemented lens formed of three lenses, where the cemented lens comprises at least one lens with negative refractive-power and at least one lens with positive refractive power;   a fourth lens group with positive refractive-power; and   a fifth lens group with positive refractive-power,   wherein the first lens group, the third lens group, and the fifth lens group are fixed groups, the second lens group and the fourth lens group are movable groups.   
     
     
         2 . The lens as claimed in  claim 1 , wherein each of the said lenses in the third group is a sphere lens respectively. 
     
     
         3 . The lens as claimed in  claim 1 , wherein focal length of the second lens group is f 2 , focal length of the lens at a wide-end is fW, focal length of the lens at a tele-end is fT and the lens satisfies a following condition expression:
   0.4<( f 2/√{square root over (( fW×fT )))}<0.6.
   
     
     
         4 . The lens as claimed in  claim 1 , wherein focal length of the fourth lens group is f 4 , focal length of the fifth lens group is f 5  and the lens satisfies a following condition expression: 
       
         
           
             
               0.25 
               < 
               
                 ( 
                 
                   
                     f 
                      
                     
                         
                     
                      
                     4 
                   
                   
                     f 
                      
                     
                         
                     
                      
                     5 
                   
                 
                 ) 
               
               < 
               
                 0.65 
                 . 
               
             
           
         
       
     
     
         5 . The lens as claimed in  claim 1 , wherein the fourth lens group and the fifth lens group respectively comprise at least one aspheric lens. 
     
     
         6 . The lens as claimed in  claim 1 , wherein the third lens group further comprises a fourth lens with positive refractive-power located between the cemented lens and the second lens group. 
     
     
         7 . The lens as claimed in  claim 1 , further comprising an aperture stop located between the second lens group and the third lens group. 
     
     
         8 . A lens, comprising, arranged in sequence, from magnifying side to minifying side:
 a first lens group with refractive-power;   a second lens group with refractive-power;   a third lens group with refractive-power, wherein the third lens group comprises a cemented lens formed of three lenses;   a fourth lens group with refractive-power; and   a fifth lens group with refractive-power,   wherein the third lens group and the fifth lens group are fixed groups, the fourth lens group are movable groups, an aperture stop is located between the first lens group and the fifth lens group.   
     
     
         9 . The lens as claimed in  claim 8 , wherein each of the said lenses in the third group is a sphere lens respectively. 
     
     
         10 . The lens as claimed in  claim 8 , wherein the forth lens group with a refractive-power of positive. 
     
     
         11 . The lens as claimed in  claim 8 , wherein the first lens group is a fixed group, and the second lens group is a movable group. 
     
     
         12 . The lens as claimed in  claim 8 , wherein the aperture stop is located between the second lens group and the third lens group. 
     
     
         13 . The lens as claimed in  claim 8 , wherein the first lens group has refractive power of positive, the second lens group has refractive power of negative, the third lens group has refractive power of positive, and the fifth lens group has refractive power of positive. 
     
     
         14 . The lens as claimed in  claim 8 , further comprising a light-filtering component for blocking light with a first wavelength range, wherein the light-filtering component is disposed on an optical axis of the lens. 
     
     
         15 . The lens as claimed in  claim 8 , wherein the light-filtering component is movable, so as to be moved in or out from the optical axis of the lens. 
     
     
         16 . The lens as claimed in  claim 8 , wherein the first wavelength range is referred to a wavelength range of infrared light. 
     
     
         17 . A lens module, having an object-side and an image-side for capturing an object light-beam from the object-side, the lens module disposed on a transmission path of the object light-beam and comprising five lens groups from the object-side to the image-side:
 a first lens group with positive refractive-power, having at least two lenses, each of the said two lenses having refractive powers of positive and negative respectively;   a second lens group with negative refractive-power, having at least two lenses, each of the said two lenses having refractive powers of positive and negative respectively;   a third lens group with positive refractive-power, having at least three lenses, the three lenses being connected mutually with substantially no space therebetween, one of the three lenses having refractive power of positive, one of the three lenses having refractive power of negative;   a fourth lens group with refractive-power, having at least two lenses, each of the said two lenses having refractive powers of positive and negative respectively; and   a fifth lens group, having at least one lens;   wherein the first lens group, the third lens group, and the fifth lens group are fixed groups, the second lens group and the fourth lens group are movable groups.   
     
     
         18 . The lens module of  claim 17 , wherein each of the said lenses in the third group is sphere lens respectively.