Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
1998-04-16
2001-04-03
Dinh, Tan (Department: 2752)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S044230, C385S016000, C359S298000
Reexamination Certificate
active
06212151
ABSTRACT:
BACKGROUND ART
A number of optical switch technologies are currently used for controlling the optical passage of light. With one technology, electric current is applied to a polymer to create a thermal effect that changes a refractive index of a polymer. As the refractive index changes, a light beam passing through the polymer is selectively routed from an input to an output. Although faster than a comparable mechanical optical switch, the switching time of polymer optical switches is limited significantly by the thermal characteristics of the polymer. Additionally, the optical properties of the light transmitted through the polymer are undesirably affected by the optical characteristics of the polymer.
Another optical switch is disclosed by Leslie A. Field et al., in “The 8
th
International Conference on Solid-State Sensors and Actuators, and Eurosensors IX, Stockholm, Sweden, Jun. 25-29, 1995.” The optical switch is micro-machined in silicon and uses a thermally activated actuator to mechanically move a single send optical fiber relative to two receive optical fibers. Field et al. exhibits relatively slow mechanical movement due to inherent thermal effects. Additionally, Field et al. provides only one degree of optical alignment, resulting in inefficient transfer of light between optical fibers due to slight misalignments.
Another micro-machined optical switch is disclosed by Levinson in U.S. Pat. No. 4,626,066. Levinson uses a cantilevered micro-machined mirror that is electrostatically positioned between a stopped and unstopped position. While Levinson's mirror may deflect light between two optical fibers, as with the aforementioned switch designs, it also is capable of optical alignment in only one dimension.
What is needed is an optical switch that provides fast and precise switching of light between one input and a plurality of outputs, or vice versa.
SUMMARY OF THE INVENTION
The present invention includes an optical switch for deflecting a beam of light between an input and an output. The optical switch comprises a first actuator disposed in an optical path of the beam of light between the input and the output and a second actuator disposed in the optical path of the beam of light between the input and the output. In an exemplary embodiment, the first actuator comprises a low-bandwidth voice coil motor. The first actuator further comprises a rotary arm and a reflector. The reflector is coupled to the arm such that the beam of light is deflected by the mirror towards the second actuator. The optical switch further comprises a position sensing detector. In the preferred embodiment, a position of the beam of light is sensed by the position sensing detector, and the deflection of the beam of light by the first actuator is a function of the sensed position of the beam of light. In an exemplary embodiment, the second actuator comprises a hi-bandwidth two-stage voice coil motor and a directing lens, which two dimensionally deflect the beam of light. The optical switch further comprises a quad detector array. In the preferred embodiment, a position of the beam of light is sensed by the quad detector array, and the two dimensional deflection of the beam of light by the second actuator is a function of the sensed position of the beam of light. In the preferred embodiment, the first and the second actuators individually or in combination selectively deflect the beam of light towards the array of lenses. In the preferred embodiment the second actuator is disposed in the optical path between the array of lenses and the first actuator. In one embodiment, the optical switch is used in an optical storage drive to direct the beam of light towards an optical storage location.
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Heanue John F.
Hrinya Stephen J.
Hurst, Jr. Jerry E.
Chu Kim-Kwok
Dinh Tan
Flehr Hohbach Test Albritton & Herbert LLP
Iolon, Inc.
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