Optical system with wavelength selecting device

Abstract

The object is to provide an optical system with a wavelength selecting device. According to one aspect of the present invention, an optical system with a wavelength selecting device includes, in order from an object along an optical axis, an objective optical system composed of optical elements having refractive power and an aperture stop, a no-power optical group composed of optical elements having no refractive power, and an imaging device. The no-power optical group includes the wavelength selecting device for making short wavelength light be selectively substantially non-transparent. The wavelength selecting device preferably satisfies the predetermined conditional expressions.

1 - 34 . (cancelled)  
   
   
       35 . An optical system comprising: 
 a plurality of lens elements; and    an optical member having wavelength selecting characteristic;    the optical member being composed of an interference film formed on a lens surface of the lens elements; and    the following conditional expressions being satisfied:     0 <|Φ/R |<0.8 0 °≦|B |<13°   where Φ denotes the effective diameter of the lens surface, R denotes the radius of curvature of the lens surface, and B denotes an angle of the principal ray passing through the lens surface relative to the optical axis at the lens surface in the air side.    
   
   
       36 . The optical system according to  claim 35 , wherein the following conditional expression is satisfied: 
       0 °≦|C |<18° where C denotes an angle of the rand ray relative to the optical axis at the lens surface in the air side, and where the rand ray is a ray coming out from an on-axis object passing on the periphery of the aperture stop to form an image.    
   
   
       37 . The optical system according to  claim 35 , wherein the optical member has substantially low transmittance with respect to the infrared light.  
   
   
       38 . The optical system according to  claim 35 , wherein the optical member has substantially low transmittance with respect to the ultraviolet light.  
   
   
       39 . The optical system according to  claim 35 , wherein the optical member has high transmittance with respect to the visible light, and substantially low transmittance with respect to both infrared light and ultraviolet light.  
   
   
       40 . An optical system comprising: 
 a plurality of lens elements; and    an optical member having wavelength selecting characteristic;    the optical member being composed of an interference film formed on a lens surface of the lens elements;    the optical system being composed of a negative lens group and a positive lens group adjoining to the negative lens group;    the negative lens group including three lens elements of a first negative lens element, a second negative lens element, and a positive lens element; and    the optical member being formed on the image side surface of the second negative lens element.    
   
   
       41 . The optical system according to  claim 40 , wherein the following conditional expressions are satisfied: 
       0 <|Φ/R |<0.8 0 °≦|B |<10° 
     where Φ denotes the effective diameter of the lens surface, R denotes the radius of curvature of the lens surface, and B denotes an angle of the principal ray passing through the lens surface relative to the optical axis at the lens surface in the air side.  
   
   
       42 . The optical system according to  claim 40 , wherein the following conditional expression is satisfied: 
       0 °≦|C |<18° where C denotes an angle of the rand ray relative to the optical axis at the lens surface in the air side, and where the rand ray is a ray coming out from an on-axis object passing on the periphery of the aperture stop to form an image.    
   
   
       43 . The optical system according to  claim 40 , wherein the optical member has substantially low transmittance with respect to the infrared light.  
   
   
       44 . The optical system according to  claim 40 , wherein the optical member has substantially low transmittance with respect to the ultraviolet light.  
   
   
       45 . The optical system according to  claim 40 , wherein the optical member has high transmittance with respect to the visible light, and substantially low transmittance with respect to both infrared light and ultraviolet light.  
   
   
       46 . An optical system comprising: 
 a plurality of lens elements; and    an optical member having wavelength selecting characteristic;    the optical member being composed of an interference film formed on a lens surface of the lens elements;    the optical system being composed of a negative lens group and a positive lens group adjoining to the negative lens group;    the positive lens group being composed of a positive lens element locating to the most object side of the positive lens group; and    the optical member being formed on the image side surface of the positive lens element.    
   
   
       47 . The optical system according to  claim 46 , wherein the following conditional expressions are satisfied: 
       0 <|Φ/R |<0.6 0 °≦|B |<13° where Φ denotes the effective diameter of the lens surface, R denotes the radius of curvature of the lens surface, and B denotes an angle of the principal ray passing through the lens surface relative to the optical axis at the lens surface in the air side.    
   
   
       48 . The optical system according to  claim 46 , wherein the following conditional expression is satisfied: 
       0 °≦|C |<18° where C denotes an angle of the rand ray relative to the optical axis at the lens surface in the air side, and where the rand ray is a ray coming out from an on-axis object passing on the periphery of the aperture stop to form an image.    
   
   
       49 . An optical system comprising: 
 a plurality of lens elements; and    an optical member having wavelength selecting characteristic;    the optical member being composed of an interference film formed on a lens surface of the lens elements;    the optical system being composed of a negative lens group, a fist positive lens group adjoining to the negative lens group, and a second positive lens group locating to the most image side of the optical system; and    the optical member being formed on the most image side surface of the second positive lens group.    
   
   
       50 . The optical system according to  claim 49 , wherein the following conditional expressions are satisfied: 
       0 <|Φ/R |<0.6 0 °≦|B |<10° where Φ denotes the effective diameter of the lens surface, R denotes the radius of curvature of the lens surface, and B denotes an angle of the principal ray passing through the lens surface relative to the optical axis at the lens surface in the air side.    
   
   
       51 . The optical system according to  claim 49 , wherein the following conditional expression is satisfied: 
       0 °≦|C |<18° where C denotes an angle of the rand ray relative to the optical axis at the lens surface in the air side, and where the rand ray is a ray coming out from an on-axis object passing on the periphery of the aperture stop to form an image.    
   
   
       52 . The optical system according to  claim 49 , wherein the optical member has substantially low transmittance with respect to the infrared light.  
   
   
       53 . The optical system according to  claim 49 , wherein the optical member has substantially low transmittance with respect to the ultraviolet light.  
   
   
       54 . The optical system according to  claim 49 , wherein the optical member has high transmittance with respect to the visible light, and substantially low transmittance with respect to both infrared light and ultraviolet light.