Loading patent…
AssigneeThe Regents of the University of California
InventorsPaul M. Hagelin, Olay Solgaard
Estimating the term…
A method of operating a micromechanical scanning apparatus includes the steps of identifying a radius of curvature value for a micromechanical mirror and modifying a laser beam to compensate for the radius of curvature value. The identifying step includes the steps of measuring the far-field optical beam radius of a laser beam reflected from the micromechanical mirror. The measured far-field optical beam radius is then divided by a theoretical far-field optical beam radius reflected from an ideal mirror to yield a ratio value M. An analytical expression for M is curve-fitted to experimental data for M with the focal-length as a fitting parameter. The focal-length value determined by this procedure, resulting in a good fit between the analytical curve and the experimental data, is equal to half the radius of curvature of the micromechanical mirror. The micromechanical scanning apparatus is operated by controlling the oscillatory motion of a first micromechanical mirror with a first micromechanical spring and regulating the oscillatory motion of a second micromechanical mirror with a second micromechanical spring.
A micromechanical scanning device, comprising:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
Scanning systems: with one or more pivoting mirrors or galvano-mirrors
Optical: systems and elements: methods
Optical: systems and elements: micromirror
Optical elements, systems or apparatus
Term ended 30 Jun 2019 (estimated)
This invention relates generally to optical scanners and displays. More particularly, this invention relates to an optical raster-scanning microelectromechanical system.
Scanning micromirrors fabricated using surface-micromachining technology are known in the art. As used herein, a micromirror, a microscopic device, a micromachined device, a micromechanical device, or a microelectromechanical device refers to a device with a third dimension above a horizontal substrate that is less than approximately several milli-meters. Such devices are constructed using semiconductor processing techniques.
Scanning micromirrors have numerous advantages over traditional scanning mirrors. For example, they have smaller size, mass, and power consumption, and can be more readily integrated with actuators, electronics, light sources, lenses and other optical elements. More complete integration simplifies packaging, reducing the manufacturing cost. These factors add motivation to the development of microfabricated scanners. In addition to displays, high-speed, high-resolution micro-optical scanners have numerous additional applications in medicine, lithography, printing, data storage and data retrieval.
Like reference numerals refer to corresponding parts throughout the drawings.
FIG. 1 is a simplified representation of an optical raster scanning system 20 constructed in accordance with an embodiment of the invention. The system 20 processes a laser beam 22 with a first mirror 30, implemented as a micromechanical device. The first mirror 30 may be a “fast mirror”, as described below, which pivots about a first axis of rotation 26, causing first rotational motion, as shown with arrow 28. As described below, the first rotational motion is achieved by pushing or pulling the bottom edge of the mirror 30.
FIG. 1 also illustrates a second mirror 24, which is also implemented as a micromechanical device. The second mirror 24 may be a “slow mirror”, as described below, which pivots about a second axis of rotation 32, causing second rotational motion, as shown with arrow 34. As described below, the second rotational motion is achieved by pushing or pulling the left and right sides of the mirror 24. By controlling the motion of the slow mirror 24 and the fast mirror 30, the laser beam 22 is projected onto a screen 36 to establish a predetermined pattern, as will be discussed further below.