Diffraction element and optical pick-up apparatus having the same
AssigneeSamsung Electronics Co., Ltd.
InventorBong-gi Kim
Life of this patent
Estimating the term…
Abstract
A diffraction element for use in an optical pick-up is capable of calculating a TE signal more stably irrespective of any assembly error in optical elements. The diffraction element of the invention is divided into three areas, a first, a second, and a third area. Each area comprises a diffraction grating with a predetermined period, and the second area is provided between the first area and the third area. The diffraction grating of the first area is substantially parallel to the diffraction grating of the third area, and the diffraction grating of the second area is substantially perpendicular to the diffraction gratings of the first and the third area.
Claims7
A diffraction element for use in an optical pick-up apparatus, comprising
- a first diffraction grating area with a first predetermined period;
- a second diffraction grating area with a second predetermined period;
- and
- a third diffraction grating area with a third predetermined period,
- wherein the diffraction grating of the first area is substantially parallel to the diffraction grating of the third area, and the diffraction grating of the second area is substantially perpendicular to the diffraction gratings of the first and the third area, wherein the first predetermined period is equal to the third predetermined period and are dislocated one-half pitch from each other, and the diffraction gratings of the first and the third area are offset by 180 degrees from each other.
An optical pick-up apparatus, comprising:
- a light source;
- a diffraction element divided into three areas, a first, a second and a third area, each comprising a diffraction grating with a predetermined period, and the second area being disposed between the first area and the third area, for diffracting a light beam emitted from the light source into three beams;
- an optical system for irradiating the beams diffracted by the diffraction element onto an optical recording medium, and guiding light reflected from the optical recording medium;
- and
- a photo diode integrated circuit (PDIC) for receiving light guided by the optical system, and detecting an RF signal, an FE signal, and a TE signal,
- wherein the diffraction grating of the first area is substantially parallel to the diffraction grating of the third area, and the diffraction grating of the second area is substantially perpendicular to the diffraction gratings of the first and the third area, and
- wherein the predetermined period of the diffraction grating of the first area is equal to the predetermined period of the diffraction grating of the third area and are dislocated one-half pitch from each other, and the diffraction gratings of the first and the third area are offset by 180 degrees from each other.
Dependencies are inferred from the claim text.