Abstract A laser pick-up device for an optical disk receives three laser beams to irradiate the optical disk and uses a six-division optical detector to detect the laser beams reflected from the optical disk and to track exactly the optical disk. A reflection type diffraction grating is positioned at a front position in order to divide and reflect the laser beam generated by a laser diode. A holographic element having the function of a toric lens is used as a diffracting device for the reflected beams. The six-division optical detector is positioned to one side and/or behind the diffraction grating. The grid gaps of the holographic element can be larger using the present invention which simplifies the manufacturing the holographic element and thereby provides a laser pick-up device that is suitable for mass production.
Inventors
👤 Seung T. Jung
👤 Soo H. Park
👤 Chun K. Kim
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-24 13:41
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/13
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
81 words
A laser pick-up device, for an optical disk comprising: a laser diode for generating a beam of laser light; a reflection-type diffraction grating that divides and reflects the light from the laser diode; a lens for focusing the light and collecting light from the optical disk; a holographic optical element that functions as a toric lens and as a diffracting device for the reflected light; and a six-division optical detector positioned behind the holographic optical element to receive the reflected light.
Claim 2
Dependent Claim
81 words
A laser pick-up device, for an optical disk comprising: a laser diode for generating a beam of laser light; a reflection-type diffraction grating that divides and reflects the light from the laser diode; a lens for focusing the light and collecting light from the optical disk; a holographic optical element that functions as a toric lens and as a diffracting device for the reflected light; and a six-division optical detector positioned behind the holographic optical element to receive the reflected light.
Claim 3
Dependent Claim
19 words
The laser pick-up device of claim 1 wherein the six-division optical detector is laterally spaced from the diffraction grating.
Claim 4
Dependent Claim
18 words
The laser pick-up device of claim 2 wherein the six-division optical detector is positioned behind the diffraction grating.
Claim 5
Dependent Claim
18 words
The laser pick-up device of claim 1 wherein the six-division optical detector is positioned behind the diffraction grating.