| |
 |
|
|
Inventor: Park; Chan-Kyu
Address: Seoul, KR
No. of patents: 4
Patents:
| Patent Number |
Title Of Patent |
Date Issued |
| 5636189 |
Astigmatic method for detecting a focussing error in an optical pickup system |
June 3, 1997 |
| An optical pickup system for determining a focussing error by utilizing an improved astigmatic method, the system comprising: a light source; an optical detector, including a square light-reception surface formed by arranging four square photoelectric cells; a beam splitter provided with |
| 5568462 |
Knife edge method for use in detecting a focussing error in an optical pickup system |
October 22, 1996 |
| The inventive knife edge method for use in an optical pick-up system capable of detecting a focussing error is comprised of a light source, an optical detector, a knife edge, an objective lens and a differential amplifier. The system is different from the optical pickup system utiliz |
| 5550368 |
Method of detecting focusing error in an optical pickup system employing a reflective knife edge |
August 27, 1996 |
| The optical pick-up system utilizing a knife edge method for a determining focusing error includes a light source, an optical detection unit, a beam splitter, an object lens, a knife edge, a pair of adders and a differential amplifier, wherein the optical detection unit further is pr |
| 5546235 |
Astigmatic lens for use in detecting a focussing error in an optical pickup system |
August 13, 1996 |
| A cylindrical astigmatic lens is used conventionally in detecting focussing errors in an optical pickup system. The inventive astigmatic lens is comprised of an orthorhombic base, made of a refractive material, provided with two parallel surfaces and a centerplane perpendicular thereto, |
|
|
|
