Active tuning of a torsional resonant structure
DCFirst Claim
1. A resonant scanning apparatus having a controllable resonant frequency, comprising:
- a first body;
a second body coupled to the first body, the first and second bodies being sized and configured for relative motion at a first resonant frequency; and
a control member coupled to one of the first and second bodies, the control member being responsive to a control signal to produce a damping force on the first or second body, wherein the first and second bodies are responsive to the damping force to move at a second resonant frequency different from the first resonant frequency.
1 Assignment
Litigations
0 Petitions
Accused Products
Abstract
A MEM s scanning device has a variable resonant frequency. In one embodiment, the MEMs device includes a flexible arm that extends from a oscillatory body. An electrical field applies a force to the flexible arm, thereby bending the flexible arm to shift the moment of inertia of the oscillatory body and a secondary mass carried by the flexible arm. The shifted moment of inertia changes the resonant frequency of the MEMs device. In another embodiment, an absorptive material forms a portion of a torsional arm that supports the oscillatory body. The mechanical properties of the absorptive material can be varied by varying the concentration of a gas surrounding the absorptive material. The varied mechanical properties change the resonant frequency of the scanning device. A display apparatus includes the scanning device and the scanning device scans about two or more axes, typically in a raster pattern. Various approaches to controlling the frequency responses of the scanning device are described, including active control of MEMs scanners and passive frequency tuning.
-
Citations
8 Claims
-
1. A resonant scanning apparatus having a controllable resonant frequency, comprising:
-
a first body;
a second body coupled to the first body, the first and second bodies being sized and configured for relative motion at a first resonant frequency; and
a control member coupled to one of the first and second bodies, the control member being responsive to a control signal to produce a damping force on the first or second body, wherein the first and second bodies are responsive to the damping force to move at a second resonant frequency different from the first resonant frequency. - View Dependent Claims (2, 3, 4)
-
-
5. A resonant scanning system, comprising:
-
a substrate;
a first body coupled for periodic motion relative to the substrate about a rotational axis;
an electrically driven first mass coupled to the first body and responsive to a control signal to move parallel to the rotational axis;
an electrically driven second mass coupled to the first body and responsive to a contrast signal to move parallel to the rotational axis; and
a control circuit coupled to drive the first and second electrically driven masses. - View Dependent Claims (6, 7, 8)
-
Specification