Optical record and reproduction apparatus with liquid crystal panel that rotates light followed by a polarizer or birefringent plate

An optical recording and reproducing apparatus, comprising:

• light source means for generating a light beam;
• means for concentrating the light beam onto an information recording medium;
• light detector means for receiving the light beam reflected by the information recording medium to obtain a tracking error signal;
• a liquid crystal panel arranged between the light source means and the concentrating means, the liquid crystal panel including a first transparent electrode having a striped form;
• a birefringent phase difference plate arranged between the liquid crystal panel and the concentrating means;
• and
• voltage application means for selectively applying a voltage to the first transparent electrode such that the liquid crystal panel rotates the polarizing direction of the light beam when no voltage is applied to the first transparent electrode,
• said birefringent phase difference plate passing the polarizing directionally rotated light beam to the concentrating means when the voltage application means supplies no voltage to the first transparent electrode, and blocking the non-polarizing directionally rotated light beam from the concentrating means when the voltage application means supplies voltage to the first transparent electrode.