Radiant energy – Photocells; circuits and apparatus – Photocell controls its own optical systems
Reexamination Certificate
2000-02-23
2003-11-25
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Photocell controls its own optical systems
C250S216000, C369S044260
Reexamination Certificate
active
06653612
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical pickup or an optical disc drive, adapted to write data to, and/or read data from, any of optical discs different in format from each other, such as compact disc (CD), digital video disc or digital versatile disc (DVD), etc. More particularly, the present invention relates to an optical pickup or optical disc drive including an optical integrated device package in which there is provided means for selecting, and providing as an output, one of results of light incidence upon a plurality of photodetectors. According to the present invention, the single optical integrated device permits to write data to, and read data from, any of different types of optical discs without increasing the number of terminals of the optical integrated device package.
2. Description of the Related Art
The conventional optical disc drive or CD player is adapted to irradiate a laser beam from an optical pickup onto an information recording surface of a CD and process a detection result of a return light from the CD surface to read or reproduce a variety of data recorded in the CD.
The conventional optical pickups include a type having a light source and photodetector disposed separately therein, and a type using an optical integrated device consisting integrally of a light source and photodetector. The U.S. Pat. Nos. 4,873,429 and 4,733,067 disclose examples of the optical pickups of the latter type. This type of optical pickup can be designed compact and have an improved reliability.
It is considered that using such an optical integrated device to build the optical pickup also in a an optical disc drive for DVD, a so-called DVD player, for example, the DVD player can be designed compact and simple. A DVD player designed compatible with a CD as well will be very conveniently usable.
In this case, by forming an optical integrated device integrally from a light source and photodetector for DVD and a light source and photodetector for CD, an optical disc player compatible with both CD and DVD can be provided.
However, when one optical integrated device is formed from two different types of light sources and photodetectors, it needs two systems for output of detected light. Namely, many terminals have to be provided on the package of the optical integrated device.
The provision of many terminals on the optical integrated device package will result in a complicate wiring of the terminals, and the package itself will not be usable with a high versatility.
OBJECT AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to overcome the above-mentioned drawbacks of the prior art by providing an optical pickup constructed from a single optical integrated device adapted to write data to, and/or read data from, more than one type of optical disc with no added terminals for the device, and an optical disc drive using the optical pickup.
According to the present invention, there is provided an optical pickup adapted to detect a return light from an optical disc by a light detecting means and provide as output a result of the light detection by the light detecting means, the optical pickup including;
optical means for emitting and converging a light onto an optical disc;
a plurality of light detecting elements forming together the light detecting means;
an optical integrated device housing the plurality of light detecting elements; and
means for selectively providing as output a result of the light detection by the light detecting means according to the type of the optical disc.
According to the present invention, there is also provided an optical disc drive using an optical pickup which detects a return light from an optical disc by a light detecting means and provides as output a result of the light detection by the light detecting means, and adapted to read data from the optical disc by processing the light detection result output from the optical pickup, the optical pickup including:
optical means for emitting and converging a light onto an optical disc;
a plurality of light detecting elements forming together the light detecting means;
an optical integrated device housing the plurality of light detecting elements; and
means for selectively providing as output a result of the light detection by the light detecting means according to the type of the optical disc.
These objects and other objects, features and advantages of the present intention will become more apparent from the following detailed description of the preferred embodiments of the present invention when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 5796701 (1998-08-01), Nishi et al.
patent: 6075659 (2000-06-01), Murayama et al.
patent: 6147941 (2000-11-01), Kumagai
patent: 02000123398 (2000-04-01), None
Le Que T.
Smid Dennis M.
LandOfFree
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