US 6,661,637 B2 · Apparatus and method to angularly position micro-optical elements

Abstract

A micro-opto-electro-mechanical transducer in which an optical element is angularly positioned by electrical field coupling. Movable electrodes of two orthogonally disposed, differential variable capacitors are coupled to the optical element constrained by structural means to angular displacement around two free-axes of rotation. Cooperating stationary capacitor electrodes with surface contoured regions facing the movable electrodes are affixed to the structural means. A thin dielectric layer of high permittivity material provides a region of fixed spacing between the capacitor electrodes. The surface contoured regions constrain the approach of the movable electrodes with angular displacement of the optical element. Both the open-loop gain and the equilibrium voltage-angle response of the transducer is largely independent of displacement. Electrostatic force feedback maintains the optical element at voltage programmed positions of static equilibrium over a wide angular range of tip and tilt. In simpler embodiments, the optical element is angularly positioned in one direction around one axis of rotation. A preferred method of control allows an electrode of each variable capacitor to be electrically grounded.

Claims19

Dependent claims

An opto-electro-mechanical transducer in which a rigid body is angularly displaced by electric field coupling around at least one free-axis of rotation comprising:

a. at least one variable capacitor with a movable electrode coupled to said rigid body constrained by structural means to angular displacement around said at least one free-axis of rotation;
b. said at least one variable capacitor having a cooperating stationary electrode affixed to said structural means and said stationary electrode having a surfaced contoured region facing said movable electrode;
c. a thin dielectric member sandwiched between the electrodes of said at least one variable capacitor;
d. said surface contoured region formed to constrain the approach of said movable electrode to said stationary electrode, whereby a condition of controlled electrostatic collapse with voltage applied to said at least one variable capacitor is maintained over a range of angular displacement of said rigid body.

1 more element

A method to fabricate an opto-electro-mechanical transducer in which a rigid body is angularly displaced by electric field coupling around at least one free-axis of rotation comprising the steps of:

a. Providing a first substrate with a planar bottom surface and a second substrate with a top portion including at least one stationary capacitor electrode with a surface contoured region;
b. forming in said first substrate a rigid body connected to structural means to constrain said rigid body to angular displacement around said at least one free-axis of rotation;
c. coupling at least one movable cooperating capacitor electrode to said rigid body;
d. affixing a thin dielectric layer to one capacitor electrode;
e. bonding said planar bottom surface of said first substrate to said second substrate in a region surrounding said surface contoured region to form at least one variable capacitor with a region of said dielectric layer in contact with portions of the electrodes of least one variable capacitor, whereby said surface contoured region constrains the approach of said at least one movable cooperating electrode with voltage applied to said at least one variable capacitor to maintain a condition of controlled electrostatic collapse over a range of angular displacement of said rigid body.

2 more elements

A method to angularly displace a rigid body by electric field coupling around at least one free-axis of rotation comprising the steps of:

a. providing at least one differential variable capacitor coupled to opposing portions of said rigid body constrained by structural means to angular displacement around at least one axis of rotation;
b. said at least one differential variable capacitor comprising two cooperating capacitors each having a portion of a thin dielectric member sandwiched between a movable electrode and a stationary cooperating electrode with a surface contoured region;
c. applying a fixed bias voltage of equal magnitude across the cooperating capacitors of said at least one differential variable capacitor;
d. superimposing a control voltage on said bias voltage to couple a corresponding at least one electrostatic torque to said rigid body, whereby said rigid body is angularly displaced to a new position of force balanced equilibrium and a condition of controlled electrostatic collapse is maintained over a range of angular displacement of said rigid body.

1 more element

Dependencies are inferred from the claim text.

Apparatus and method to angularly position micro-optical elements

Life of this patent

Apparatus and method to angularly position micro-optical elements

Life of this patent

Abstract

Claims19