Image pickup apparatus and image pickup unit having device for removing foreign substance deposited on surface of optical member

Abstract

An image pickup unit integrally includes an optical lowpass filter, a piezoelectric element, and an image pickup element. The optical lowpass filter is separated into a plurality of grouped optical members in an imaging light axis direction. The optical lowpass filter includes first to third grouped optical members. To remove a foreign substance, such as dust or dirt, deposited on the surface of the first grouped optical member, the piezoelectric element vibrates the first grouped optical member. The first grouped optical member has a monocrystalline structure having a Q value indicating the sharpness of resonance higher than that of glass, which is an amorphous material, and a low attenuation characteristic so as to efficiently vibrate the first grouped optical member.

1 . An image pickup apparatus having an image pickup element configured to convert an optical image of an object into an electrical signal, comprising:
 an optical member disposed in front of the image pickup element, the optical member being separated into a plurality of grouped sub-optical members in an imaging light axis direction; and   a vibrating unit configured to vibrate a first grouped sub-optical member disposed at a forefront position in the optical member,   wherein the first grouped sub-optical member is formed from a monocrystalline plate.   
   
   
       2 . The image pickup apparatus according to  claim 1 , wherein the monocrystalline plate is a quartz birefringent plate. 
   
   
       3 . The image pickup apparatus according to  claim 1 , wherein a surface of the monocrystalline plate is coated so as to provide optical functionality. 
   
   
       4 . The image pickup apparatus according to  claim 3 , wherein the optical functionality includes reflection of at least one of an infrared light beam and an ultraviolet light beam. 
   
   
       5 . The image pickup apparatus according to  claim 1 , wherein a second grouped sub-optical member of the optical member is disposed on the side of the first grouped sub-optical member close to the image pickup element, and wherein the second grouped sub-optical member includes at least one of a birefringent plate, a phase plate, and an infrared absorption glass. 
   
   
       6 . The image pickup apparatus according to  claim 1 , wherein a third grouped sub-optical member of the optical member is integrally bonded and secured to the image pickup element. 
   
   
       7 . The image pickup apparatus according to  claim 3 , further comprising a holding member configured to hold the first grouped sub-optical member and the second grouped sub-optical member. 
   
   
       8 . The image pickup apparatus according to  claim 1 , wherein the vibrating unit vibrates the first grouped sub-optical member in a direction perpendicular to the imaging light axis. 
   
   
       9 . An image pickup unit included in an image pickup apparatus, comprising:
 an image pickup element configured to convert an optical image of an object into an electrical signal;   an optical member disposed in front of the image pickup element, the optical member being separated into a plurality of grouped sub-optical members in an imaging light axis direction; and   a vibrating unit configured to vibrate a first grouped sub-optical member disposed at a forefront position in the optical member,   wherein the first grouped sub-optical member is formed from a monocrystalline plate.   
   
   
       10 . The image pickup unit according to  claim 9 , wherein the monocrystalline plate is a quartz birefringent plate. 
   
   
       11 . The image pickup unit according to  claim 9 , wherein a surface of the monocrystalline plate is coated so as to provide optical functionality. 
   
   
       12 . The image pickup unit according to  claim 11 , wherein the optical functionality includes reflection of at least one of an infrared light beam and an ultraviolet light beam. 
   
   
       13 . The image pickup unit according to  claim 9 , wherein a second grouped sub-optical member of the optical member is disposed on the side of the first grouped sub-optical member close to the image pickup element, and wherein the second grouped sub-optical member includes at least one of a birefringent plate, a phase plate, and an infrared absorption glass. 
   
   
       14 . The image pickup unit according to  claim 9 , wherein a third grouped sub-optical member of the optical member is integrally bonded and secured to the image pickup element. 
   
   
       15 . The image pickup unit according to  claim 11 , further comprising a holding member configured to hold the first grouped sub-optical member and the second grouped sub-optical member. 
   
   
       16 . The image pickup unit according to  claim 9 , wherein the vibrating unit vibrates the first grouped sub-optical member in a direction perpendicular to the imaging light axis.