Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
2000-10-04
2003-10-07
Hindi, Nabil (Department: 2655)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S112280, C369S044110
Reexamination Certificate
active
06631113
ABSTRACT:
BACKGROUND
1. Field of the Invention
The present invention relates to a system that connects an optical head to additional electronics in an optical drive.
2. Description of Related Art
A conventional optical drive (e.g., a compact disk player) typically includes a stationary optical unit, a movable optical unit, and an actuator. The stationary optical unit generally includes a laser diode, a half mirror, and a photodetector. The laser diode generates a light beam that is reflected by the half mirror onto the movable optical unit. The movable optical unit typically includes an objective lens that focuses the light beam on a spinning optical disk.
The actuator aligns the movable optical unit with the tracks of the optical disk so that the light beam reflects off the lands and pits of the tracks. The reflected light beam travels back through the movable optical unit and back to the stationary optical unit. The light beam is transmitted through the half mirror onto the photodetector where the varying intensity of the light is changed to electrical signals.
Optical drives are becoming smaller so they can be integrated into portable devices including laptop computers and personal digital assistants (PDAs). Close arrangement and integration of components help to miniaturize optical drives. For example, the stationary and movable optical units described above can be integrated into a single component (an integrated optical head) called “optical pickup unit” or “OPU”. An actuator arm can then be used to place the OPU over the tracks of a spinning medium.
FIG. 1
illustrates an assembly
10
used to connect an OPU
20
to a printed circuit board
60
(or electronics of an optical drive). OPU
20
is mounted atop a copper plate
30
through a cutout of a fiberglass layer
40
. Fiberglass layer
40
includes pad
42
, pad
44
, and trace
46
. Pad
42
of fiberglass layer
40
is coupled to pad
22
of OPU
20
via a bond wire
25
. Plate
30
is mounted atop a flexible circuit
50
(or vice versa). Flexible circuit
50
includes pad
52
, trace
54
, and a connector
56
. Pad
44
of fiberglass layer
40
is coupled to pad
52
of flexible circuit
50
via a solder joint
35
. Flexible circuit
50
is next coupled to a printed circuit board
60
via connector
56
.
Assembly
10
has several disadvantages. Each of the wire bonds and solder joints in assembly
10
forms a point of failure that may break during use. Thus, the many wire bonds and solder joints in assembly
10
create multiple points of failure. Each of the wire bonds and solder joints must be formed during fabrication. Thus, the many wire bonds and solder joints increase fabrication cost. Solder joints also require large pads, thereby increasing the overall size of the fiberglass and flexible circuit layers. Assembly
10
is also constructed from multiple layers of silicon, fiberglass, copper, and flex circuit that increase the overall weight and volume of the optical drive. Accordingly, there is a need for a method and a system to connect the OPU to the remaining electronics of the optical drive while improving reliability and minimizing weight and volume.
SUMMARY
An optical assembly includes an optical head, an actuator an for positioning the optical head, and a flex circuit for carrying signals from the optical head. The flex circuit is coupled to the optical head by at least one wire. In one embodiment, the flex circuit carries signals from the optical head to a printed circuit board. In one implementation, the flex circuit also carries signals from the printed circuit to the optical head.
In one embodiment, the optical head is mounted atop a plate, the plate is mounted atop the flex circuit, and the wire couples a pad on the flex circuit to a pad on the optical head through a cutout in the plate. In another embodiment, the flex circuit is mounted atop a plate and the optical head is mounted atop the plate. In one implementation, the optical head is mounted atop the plate through a cutout of the flex circuit.
The optical assembly described above eliminates the use of an intermediate fiberglass layer, thereby improving reliability by reducing the number of wire bonds and conserving weigh and volume of the optical assembly.
REFERENCES:
patent: 4965684 (1990-10-01), Stefansky
patent: 5010246 (1991-04-01), Tsuyuguchi et al.
patent: 5351229 (1994-09-01), Brezoczky et al.
patent: 5805377 (1998-09-01), Lerdal et al.
patent: 6052357 (2000-04-01), Ogawa et al.
patent: 6104690 (2000-08-01), Feldman et al.
patent: 0 862 168 (1998-09-01), None
Abrahamson Scott D.
Berg Thomas E.
Freeman Robert D.
DPHI Acquisitions, Inc.
Hindi Nabil
MacPherson Kwok & Chen & Heid LLP
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