Optical disc apparatus

Abstract

An optical disk apparatus having a high reliability by evading collision between a condensing lens and an optical disk regardless whether the focus control is in the operative state or in the inoperative state, thereby preventing damage to the condensing lens and the optical disk. When the focus control is in the inoperative state, by using a reflection light amount from the optical disk ( 1 ), it is ascertained that the focus of the light beam is in the vicinity of the information surface and the condensing lens ( 15 ) is driven to be apart from the optical disk ( 1 ).

1 - 33 . (canceled)  
   
   
       34 . An optical disk apparatus, comprising: 
 a converging means for converging and irradiating a light beam from a light source toward a rotating information carrier;    a focus displacement signal detection means for generating a signal in accordance with a positional displacement of a focus of the light beam with respect to an information surface of the information carrier; 
 a focus shifting means for shifting the converging means in a direction normal to the information surface of the information carrier;  
   a focus control means for driving the focus shifting means in accordance with the signal from the focus displacement signal detection means, and performing a control such that the focus of the light beam follows the information surface of the information carrier; and    a search means for shifting the converging means such that the light beam is irradiated onto a desired track on the information carrier;    wherein the search means sets the focus control means to an inoperative state if the focus control means is operative and if the number of tracks across which the focus of the light beam is shifted is a predetermined number or greater.    
   
   
       35 . An optical disk apparatus, comprising: 
 a converging means for converging and irradiating a light beam from a light source toward a rotating information carrier;    a focus displacement signal detection means for generating a signal in accordance with a positional displacement of a focus of the light beam with respect to an information surface of the information carrier;    a focus shifting means for shifting the converging means in a direction normal to the information surface of the information carrier;    a focus control means for driving the focus shifting means in accordance with the signal from the focus displacement signal detection means, and performing a control such that the focus of the light beam follows the information surface of the information carrier; and    a search means for shifting the converging means such that the light beam is irradiated onto a desired track on the information carrier;    wherein the search means sets the focus control means to an inoperative state if the focus control means is operative and if the direction in which the focus of the light beam is shifted across the tracks is a direction toward the outer periphery of the information carrier.    
   
   
       36 . An optical disk apparatus, comprising: 
 a converging means for converging and irradiating a light beam from a light source toward a rotating information carrier;    a focus displacement signal detection means for generating a signal in accordance with a positional displacement of a focus of the light beam with respect to an information surface of the information carrier;    a focus shifting means for shifting the converging means in a direction normal to the information surface of the information carrier;    a focus control means for driving the focus shifting means in accordance with the signal from the focus displacement signal detection means, and performing a control such that the focus of the light beam follows the information surface of the information carrier; and    a search means for shifting the converging means such that the light beam is irradiated onto a desired track on the information carrier;    wherein the search means sets the focus control means to an inoperative state if the focus control means is operative and if a target track to which the focus of the light beam is to be shifted transversely is within a range of a predetermined distance from the outermost periphery of the information carrier.