Ludwig Ceshkovsky

US Patent:

5703847, Dec 30, 1997

Filed:

Jun 7, 1995

Appl. No.:

8/474424

Inventors:

Ludwig Ceshkovsky - Fountain Valley CA

Assignee:

Discovision Associates - Irvine CA

International Classification:

G11B 7085

US Classification:

369 4428

Abstract:

The present invention allows the light beam of an optical disc storage device to radially move between different information tracks of an optical disc while the storage device tracking servo loop remains in a continuous closed loop mode of operation. The invention operates to radially move a light beam from one information track to another during a closed loop mode of operation by activating two control signals introduced into the closed tracking servo loop to create a phantom track center that radially moves across the optical disc. Because the tracking servo loop is in a closed loop mode of operation, the tracking servo operates to keep the light beam centered on the point that the tracking servo considers to be the center of an information track; in this case the phantom track center. Therefore, the tracking servo causes the light beam to radially move across the disc in a closed loop mode of operation by keeping the light beam centered on the moving phantom track center.

US Patent:

6744711, Jun 1, 2004

Filed:

Jun 20, 2000

Appl. No.:

09/597941

Inventors:

Ludwig Ceshkovsky - Irvine CA

Assignee:

Discovision Associates - Irvine CA

International Classification:

G11B 700

US Classification:

369 4428, 369 4429

Abstract:

An apparatus and method conducts a high-speed search on an optical medium having a plurality of tracks on which information is recorded. At least a first light spot and a second light spot are directed by the apparatus onto the optical medium. The light spots traverse across the tracks in one of a first direction and a second direction. A photodetector unit receives a reflected component of the first light spot to form a first electrical signal and a reflected component of the second light spot to form a second electrical signal. Digital shaping circuitry respectively converts the first electrical signal and the second electrical signal into a first digital signal and a second digital signal. A quadrature detector is configured to receive the first digital signal and the second digital signal. The first digital signal and the second digital signal are arranged in a quadrature relationship to each other.

US Patent:

6982935, Jan 3, 2006

Filed:

Feb 1, 2002

Appl. No.:

09/683684

Inventors:

Ludwig Ceshkovsky - Irvine CA, US

Assignee:

Discovision Associates - Irvine CA

International Classification:

G11B 7/085

US Classification:

369 3012, 369 3016, 369 4428, 369 4429

Abstract:

A method and apparatus for suspending the operation of a rotating optical media player that uses simplified and efficient logic circuitry is described. When an operator initiates a pause operation, for example, by pressing a pause key, the current location of an optical pickup (e. g. , a value of the current track ID) is stored. Then, a tracking servo loop is opened and a near zero offset is provided to the input of the tracking actuator. The condition of the optical disk system is then maintained in a “wait” state until the operator decides to end the pause process by selecting an alternate operation, such as “Play”, “Search”, or some other functions. When an alternate operation is received, the tracking servo loop is closed. The system then enters a search mode to reposition the optical head to the position indicated by the track ID, which was previously saved. Finally, the selected function command is activated.

US Patent:

7038979, May 2, 2006

Filed:

Apr 2, 2004

Appl. No.:

10/708963

Inventors:

Ludwig Ceshkovsky - Irvine CA, US

Assignee:

Discovision Associates - Irvine CA

International Classification:

G11B 7/00

US Classification:

369 4428, 369 4429

Abstract:

An apparatus and method for high-speed searching of an optical medium having a plurality of tracks. Light spots are directed by the apparatus onto the optical medium. As the spots traverse across the tracks in one of a first direction and a second direction, a photodetector unit receives reflected components of the light spots, thus forming respective electrical signals. Digital shaping circuitry converts the electrical signals into digital signals. A quadrature detector receives the digital signals which are arranged in quadrature relationship to each other, and produces an up-count signal indicating the light spots are traversing the tracks in the first direction and a down-count signal indicating the light spots are traversing the tracks in the second direction. A counter counts the up-count signal and the down-count signal to determine a number of tracks traversed by the light spots.

US Patent:

7061853, Jun 13, 2006

Filed:

Dec 18, 2001

Appl. No.:

09/683359

Inventors:

Ludwig Ceshkovsky - Irvine CA, US

Assignee:

Discovision Associates - Irvine CA

International Classification:

G11B 7/00

US Classification:

36912412, 26912403, 269 4441

Abstract:

An optical pickup is described with an electronically adjustable beam spot size for reading optical media. Two proximal light sources are impinged on a selected track of the media and the reflected light is registered by photodetector arrays. The electrical signal generated from the leading detector is delayed, based on a distance between beams and the speed of the media, to achieve a desired amount of temporal coincidence with the electrical signal associated with the lagging beam. The electrical signals are combined, such as in a multiplier circuit, to create a third electrical signal whose response to a data bit can be adjusted to a shorter duration than the responses from either first or second beams. Therefore, the effective spot size may be electronically controlled, wherein light sources of longer wavelengths may be utilized, and optical data storage systems may be configured for reading media having different optical characteristics.

US Patent:

7936659, May 3, 2011

Filed:

Jul 3, 2002

Appl. No.:

10/190382

Inventors:

Ludwig Ceshkovsky - Irvine CA, US

Assignee:

Discovision Associates - Irvine CA

International Classification:

G11B 7/00

US Classification:

36912402, 36911216, 369 4441, 369 4426

Abstract:

The present invention uses a stationary medium and a stationary optical pickup unit. The stationary optical pickup unit has a laser, which sends a beam of light through an objective lens, which focuses the beam on a point on the track of the stationary medium. The beam is then reflected toward a re-directing surface (e. g. , prism) which diverts it to a photodiode array. Instead of the entire optical pickup moving to follow the track as in conventional systems, only the objective lens inside of the optical pickup moves. The position of the objective lens determines where on the information track the laser will reach. Depending upon where the laser beam reaches, the reflected light beam received by the photodetector array changes. This, in turn, affects the amount of light sensed by each photodetector in the array, thereby causing the output of each of the four photodetectors to change each time the objective lens moves. To implement the invention, the output of the photodetector array is manipulated wherein the manipulated signal corresponds to the signal that would be received if the photodetector were actually following the track directly above the laser as in prior art systems.

US Patent:

RE325740, Jan 5, 1988

Filed:

Sep 9, 1985

Appl. No.:

6/773770

Inventors:

Ludwig Ceshkovsky - Fountain Valley CA
Wayne R. Dakin - Huntington Beach CA

Assignee:

Discovision Associates - Costa Mesa CA

International Classification:

G11B 700
G11B 1700

US Classification:

369 32

Abstract:

A method and apparatus for selectably retrieving information from any of a plurality of spirally-formed information tracks formed in a video disc by means of controlling a carriage for translating the video disc in a forward or a reverse direction relative to radiant beam information recovery means in a video disc player. Each information track is identified by a unique address and means are provided for selecting the address of a particular track to be retrieved. A prescribed sequence of drive signals is applied to a carriage motor dependent on the distance to be traveled by the carriage to retrieve the selected information, the drive signals being successively stepped downward to intermittently redetermine carriage motor speed as predetermined location thresholds are reached during carriage translation.

US Patent:

61341991, Oct 17, 2000

Filed:

May 29, 1998

Appl. No.:

9/088106

Inventors:

Ludwig Ceshkovsky - Fountain Valley CA

Assignee:

Discovision Associates - Irvine CA

International Classification:

G11B 700

US Classification:

369 4435

Abstract:

An technique is disclosed for focus control of a beam of radiant energy, wherein a detector of the beam has first and second outputs responsive to a position of the beam. A circuit is coupled to the outputs of the detector for producing an error signal representing a displacement of the focus from a predetermined position, wherein the error signal has a periodic characteristic relative to the displacement. A servo responsive to the error signal restores the displaced beam to the predetermined position. A local feedback loop is coupled to the outputs of the detector, and includes first and second periodic function generators, each responsive to the error signal. The second periodic function generator has an output that differs from an output of the first periodic function generator by a phase angle, preferably 90 degrees. A first multiplier multiplies the first output of the detector by the output of the first periodic function generator. A second multiplier multiplies the second output of the detector by the output of the second periodic function generator, wherein the outputs of the first and second multipliers are provided as inputs of the circuit to modify the error signal.