Ultraviolet acoustooptic device and optical imaging device

Abstract

The present invention provides an ultraviolet acoustooptic device including: a radio-frequency signal input part; a transducer unit for converting a radio-frequency signal into a mechanical vibration; and an acoustooptic medium whose optical characteristic varies according to the mechanical vibration. In the ultraviolet acoustooptic device, light entering the acoustooptic medium is ultraviolet light having a wavelength of 380 nm or shorter, and the acoustooptic medium is formed of an oxide single crystal containing at least boron as a component of its unit cell, a LiNbO 3 crystal, or a LiNbO 3 crystal doped with MgO. Thus, an acoustooptic device can be obtained in which no laser damage nor optical damage is caused, and an ultraviolet acoustooptic device and an optical imaging apparatus using the same can be provided that do not necessarily require to be water-cooled.

1 - 19 . (canceled)  
   
   
       20 . An ultraviolet acoustooptic device, comprising: 
 a radio-frequency signal input part;    a transducer unit for converting a radio-frequency signal into a mechanical vibration; and    an acoustooptic medium whose optical characteristic varies according to the mechanical vibration,    wherein light entering the acoustooptic medium is ultraviolet light having a wavelength of 380 nm or shorter, and the acoustooptic medium is formed of a LiNbO 3  crystal, and    the acoustooptic medium transmits ultraviolet light therethrough.    
   
   
       21 . The ultraviolet acoustooptic device according to  claim 20 , wherein the LiNbO 3  crystal is doped with MgO.  
   
   
       22 . The ultraviolet acoustooptic device according to  claim 21 , wherein a doping amount of MgO is 7 mol. % or less.  
   
   
       23 . The ultraviolet acoustooptic device according to  claim 22 , wherein the doping amount is 0.5 mol. % to 7 mol. %.  
   
   
       24 . The ultraviolet acoustooptic device according to  claim 20 , wherein at least a part of the acoustooptic medium further is covered with a high thermal conductive sheet.  
   
   
       25 . The ultraviolet acoustooptic device according to  claim 24 , wherein the high thermal conductive sheet is a graphite sheet.  
   
   
       26 . The ultraviolet acoustooptic device according to  claim 20 , wherein the light entering the acoustooptic medium is ultraviolet light having a wavelength in a range of 160 nm to 380 nm.  
   
   
       27 . An optical imaging apparatus, comprising: 
 a light source for emitting light with a wavelength of 380 nm or shorter;    an ultraviolet acoustooptic device for diffracting light emitted from the light source;    a driving circuit; and    an image plane on which light diffracted by the ultraviolet acoustooptic device forms an image,    wherein the ultraviolet acoustooptic device includes an acoustooptic medium formed of a LiNbO 3  crystal, and    the acoustooptic medium transmits ultraviolet light therethrough.    
   
   
       28 . The optical imaging apparatus according to  claim 27 , wherein the LiNbO 3  crystal is doped with MgO.  
   
   
       29 . The optical imaging apparatus according to  claim 27 , further comprising a movable mirror for forming an image on the image plane with the light diffracted by the ultraviolet acoustooptic device, with the movable mirror being disposed between the ultraviolet acoustooptic device and the image plane.  
   
   
       30 . The optical imaging apparatus according to  claim 27 , wherein at least a part of the acoustooptic medium further is covered with a high thermal conductive sheet.  
   
   
       31 . The optical imaging apparatus according to  claim 27 , wherein the high thermal conductive sheet is a graphite sheet.  
   
   
       32 . The optical imaging apparatus according to  claim 29 , further comprising a beam stopper for shielding light transmitted through the ultraviolet acoustooptic device, with the beam stopper being disposed on a side where the light transmitted through the ultraviolet acoustooptic device travels.  
   
   
       33 . The optical imaging apparatus according to  claim 27 , wherein the image plane is a photoreceptor.  
   
   
       34 . The optical imaging apparatus according to  claim 33 , wherein phosphors are used as the photoreceptor for the image plane.  
   
   
       35 . The optical imaging apparatus according to  claim 34 , wherein phosphors corresponding to red, green, and blue are used as the photoreceptor for the image plane.  
   
   
       36 . The optical imaging apparatus according to  claim 27 , wherein the light source emits light with a wavelength in a range of 160 nm to 380 nm.  
   
   
       37 . A method for diffracting ultraviolet light by an ultraviolet acoustooptic device, the device comprising: 
 a radio-frequency signal input part;    a transducer unit for converting a radio-frequency signal into a mechanical vibration; and    an acoustooptic medium whose optical characteristic varies according to the mechanical vibration, the medium being formed of a LiNbO 3  crystal,    wherein the acoustooptic medium transmits ultraviolet light therethrough,    the method comprising the steps of:    allowing ultraviolet light having a wavelength of 380 nm or shorter to enter the acoustooptic medium; and    applying a radio frequency to the radio-frequency signal input part so that the ultraviolet light is diffracted.    
   
   
       38 . The method according to  claim 37 , wherein the LiNbO 3  crystal is doped with MgO.  
   
   
       39 . The method according to  claim 37 , wherein the ultraviolet light has a wavelength in a range of 160 nm to 380 nm.