Information reading apparatus with a light beam scanning technique

An information reading apparatus for reading information from a record medium having an information recording region in which the information is recorded and a synchronizing signal recording region in which synchronizing signals corresponding to the information are recorded, comprising:

• a board havng an optical waveguide and a scanning surface opposite the record medium;
• means for emitting a light into the optical waveguide in a predetermined direction;
• first and second photodetecting means provided at the board;
• means for dividing the light from the emitting means into a first light beam and a second light beam;
• means for scanning the first light beam within a range corresponding to a width of the information recording region;
• a first optical system formed in the board, for conducting the first light beam to the information recording region of the record medium, though the waveguide and the scanning surface, and leading a reflected light beam from the information recording region to the first photodetecting means;
• a second optical system formed in the board, for conducting the second light beam to the synchronizing signal recording region of the record medium, through the waveguide and the scanning surface, and leading a reflected light beam from the synchronizing signal recording region to the second photodetecting means;
• and
• signal processing means for driving the scanning means in accordance with a synchronizing signal detected by the second photodetecting means, and for enabling a signal from the first photodetecting means in accordance with the synchronizing signal.

An information reading apparatus for reading information from a record medium having an information recording region in which the information is recorded, and a synchronizing signal recording region in which synchronizing signals corresponding to the information are recorded, comprising;

• a board having an optical waveguide and a scanning surface opposite the record medium;
• first and second emitting means for emitting light into the waveguide of the board;
• first and second photodetecting means;
• ultrasonic generating means for generating a surface elastic wave in an optical path of the first optical system, to diffract with said elastic wave at least part of the light emitted from the first emitting means;
• and
• a first optical system formed in the board, for conducting the light beam diffracted by the elastic wave to the information recording region of the recording medium, through the waveguide and the scanning surface, and leading a reflected light beam from the information recording region to the first photodetecting means;
• a second optical system formed in the board, for conducting light emitted from the second emitting means to the synchronizing signal recording region of the record medium, through the waveguide and the scanning surface, and leading a reflected light beam from the synchronizing signal recording region to the second photodetecting means;
• and
• signal processing means for driving the ultrasonic generating means in accordance with a synchronizing signal detected by the second photodetecting means to continuously change the frequency of the surface elastic wave during a given time period, and for enabling a signal from the first photodetecting means in accordance with the synchronizing signal.