Information recording apparatus and information recording method

Abstract

In the information recording apparatus, by driving the light source by the pulse signal corresponding to the recording signal, the laser pulse corresponding to the recording signal is irradiated onto the recording medium. The recording signal has the mark period to form the recording mark, and the space period in which the recording mark is not formed. In the mark period, the output level of the laser pulse changes between the normal level and the writing level, thereby, the recording mark is formed on the recording medium. On the one hand, over a predetermined period in the space period, the output level of the laser pulse is changed to the low level lower than the normal level. Thereby, the heat accumulation onto the recording medium, due to the transient response of the laser pulse in the mark period, is reduced, and in the mark period after that, the correct recording mark can be formed.

What is claimed is:  
     
         1 . An information recording apparatus in which a laser light is irradiated onto a recording medium and a recording mark corresponding to a recording signal is formed, 
 said information recording apparatus comprising:    a light source to emit the laser light; and    a controller which controls to irradiate a laser pulse onto the recording medium when said light source is driven according to the recording signal, wherein    said controller includes;    a mark controller by which, during a mark-period of the recording signal, an output level of the laser pulse is changed corresponding to the recording signal between a normal level and a writing level higher than the normal level; and    a space controller by which, during at least several space periods in the recording signal, the output level of the laser pulse is changed to a low level lower than the normal level covering over a predetermined period.    
     
     
         2 . The information recording apparatus according to  claim 1 , wherein 
 the low level lower than the normal level is zero level.    
     
     
         3 . The information recording apparatus according to  claim 1 , wherein 
 said space controller changes the output level of the laser pulse to the low level lower than the normal level only in the space period in which the time width is short.    
     
     
         4 . The information recording apparatus according to  claim 3 , wherein 
 the space period in which the time width is short is a space period of 3T or 4T.    
     
     
         5 . The information recording apparatus according to  claim 1 , wherein 
 said space controller changes the output level of the laser pulse to the low level lower than the normal level in all space periods.    
     
     
         6 . The information recording apparatus according to  claim 1 , wherein 
 in the space period in which the time width is long, said space controller changes the output level of the laser pulse to the low level covering over the predetermined first period, and    in the space period in which the time width is short, said space controller changes the output level of the laser pulse to the low level covering over the second period longer than the fist period.    
     
     
         7 . The information recording apparatus according to  claim 6 , wherein 
 the space period in which the time width is short is a space period of 3T or 4T, and    the space period in which the time width is long is a space period of 5T or more.    
     
     
         8 . The information recording apparatus according to  claim 1 , further comprising: 
 a level adjuster which automatically adjusts the output level of the laser pulse covering over the level adjustment period in the predetermined space period, wherein    said space controller changes the output level of the laser pulse to the low level lower than the normal level only in the space period in which the automatic adjustment of the output level is not conducted.    
     
     
         9 . The information recording apparatus according to  claim 1 , further comprising: 
 a level adjuster which automatically adjusts the output level of the laser pulse covering over the level adjustment period in the predetermined space period, wherein    said space controller changes the output level of the laser pulse to the low level lower than the normal level in the period except the level adjustment period in all space periods.    
     
     
         10 . The information recording apparatus according to  claim 1 , further comprising: 
 a level adjuster which automatically adjusts the output level of the laser pulse covering over the level adjustment period in the predetermined space period, wherein    in the space period in which the automatic adjustment of the output level is conducted, said space controller changes the output level of the laser pulse to the low level covering over the predetermined first period which is not overlapped with the level adjustment period, and    in the space period in which the automatic adjustment of the output level is not conducted, said space controller changes the output level of the laser pulse to the low level covering over the second period which is longer than the first period.    
     
     
         11 . The information recording apparatus according to  claim 1 , wherein 
 the recording medium can records only once, and    the normal level is the reading level.    
     
     
         12 . The information recording apparatus according to  claim 1 , wherein 
 the recording medium can write or erase for a plurality of times, and    the normal level is an erasing level.    
     
     
         13 . The information recording apparatus according to  claim 1 , wherein 
 said space controller changes the output level of the laser pulse to the low level lower than the normal level from the top of the space period.    
     
     
         14 . An information recording method in which the laser light is irradiated onto a recording medium and a recording mark corresponding to a recording signal is formed, 
 said information recording method comprising the steps of:    emitting a laser light; and    irradiating a laser pulse onto the recording medium by driving a light source according to the recording signal, wherein the step of irradiating the laser pulse includes the steps of;    during a mark period of the recording signal, changing an output level of the laser pulse between a normal level and a writing level higher than the normal level, corresponding to the recording signal, and    during at least several space periods of the recording signal, changing the output level of the laser pulse to a low level lower than the normal level covering over a predetermined period.