Light irradiation apparatus and information rewritable system

Abstract

A light irradiation apparatus includes an irradiation unit including a light source to emit light to a process-target object, a light source driving circuit to drive the light source, a light source controller to control the light source driving circuit to change a light output level of the light source, and a light spot controller to control energy or energy density of a beam spot of the light on the process-target object depending on an operation mode, and a transition mode that one operation mode is being changed to another mode. The light spot controller sets the energy or energy density during the transition mode lower compared to either of the energy or energy density during the one operation mode before the transition mode and the energy or energy density during the another mode after the transition mode.

What is claimed is: 
     
         1 . A light irradiation apparatus comprising:
 an irradiation circuit including a light source to irradiate laser light to a process-target object;   a light source driving circuit to drive the light source;   a light source controller to control the light source driving circuit to change a light output level of the light source; and   a travelling direction controller to control a travelling direction of the light emitted from the light source depending on an operation mode, and a transition mode that one operation mode is being changed to another mode,   wherein the travelling direction controller controls the travelling direction of the light during the transition mode to a direction that the light does not irradiate the process-target object.   
     
     
         2 . The light irradiation apparatus of  claim 1 , wherein the travelling direction controller includes a deflector to deflect the light emitted from the light source. 
     
     
         3 . The light irradiation apparatus of  claim 1 , wherein the irradiation circuit further includes a scanner to scan the process-target object by using the light emitted from the light source, and the travelling direction controller controls the travelling direction by using the scanner. 
     
     
         4 . The light irradiation apparatus of  claim 1 , further comprising:
 a light shield disposed at a position deviated from a light path of the light extending from the light source to the process-target object, and   the travelling direction controller directs the travelling direction to the light shield during the transition mode.   
     
     
         5 . The light irradiation apparatus of  claim 1 , wherein the travelling direction controller directs the travelling direction of the light to a non-effective area where structural transformation the process-target object does not occur during the transition mode. 
     
     
         6 . The light irradiation apparatus of  claim 4 , wherein the light shield performs heat conversion or light dispersion for at least a part of incident light that enters the light shield. 
     
     
         7 . The light irradiation apparatus of  claim 1 ,
 wherein the light source driving circuit includes:   an output filter having an inductive element and a capacitive element;   a power source electrically connectable with the output filter;   a switch to switch electrical conduction and non-conduction between the light source and the output filter;   a light emission controller to control the switch based on the light output level; and   a current control system to control a current supplied from the power source to the light source via the output filter based on a set current value of the light output level.   
     
     
         8 . The light irradiation apparatus of  claim 7 , wherein the process-target object is a reversible thermal recording medium,
 wherein the light source controller changes the light output level between a first light output level and a second light output level, the first light output level is used for the image recording on the reversible thermal recording medium, and the second light output level is used for the image erasing on the reversible thermal recording medium.   
     
     
         9 . An information rewritable system comprising:
 the light irradiation apparatus  claim 8 , and   a transport circuit to transport one or more objects attached with the reversible thermal recording medium on a conveying path while the one or more objects attached with the reversible thermal recording medium faces the light irradiation apparatus at one position the conveying path.   
     
     
         10 . A light irradiation apparatus comprising:
 an irradiation circuit including a light source to irradiate light to a process-target object;   a light source driving circuit to drive the light source;   a light source controller to control the light source driving circuit to change a light output level of the light source;   a light shield moveable between a light block position to block the light emitted from the light source at least partially, and a retraction position retracted from the light block position; and   a position controller to control a position of the light shield at the light block position during a transition mode.   
     
     
         11 . The light irradiation apparatus of  claim 10 , wherein the light shield is an aperture stop. 
     
     
         12 . The light irradiation apparatus of  claim 10 , wherein the light shield performs heat conversion or light dispersion for at least a part of incident light that enters the light shield. 
     
     
         13 . The light irradiation apparatus of  claim 10 ,
 wherein the light source driving circuit includes:   an output filter having an inductive element and a capacitive element;   a power source electrically connectable with the output filter;   a switch to switch electrical conduction and non-conduction between the light source and the output filter;   a light emission controller to control the switch based on the light output level; and   a current control system to control a current supplied from the power source to the light source via the output filter based on a set current value of the light output level.   
     
     
         14 . The light irradiation apparatus of  claim 13 , wherein the process-target object is a reversible thermal recording medium,
 wherein the light source controller changes the light output level between a first light output level and a second light output level, the first light output level is used for an image recording on the reversible thermal recording medium, and the second light output level is used for an image erasing on the reversible thermal recording medium.   
     
     
         15 . An information rewritable system comprising:
 the light irradiation apparatus of  claim 14 , and   a transport circuit to transport one or more objects attached with the reversible thermal recording medium on a conveying path while the one or more objects attached with the reversible thermal recording medium faces the light irradiation apparatus at one position the conveying path.