Method and device for scanning light

• US 9,304,316 B2
• Filed: 06/08/2014
• Issued: 04/05/2016
• Est. Priority Date: 11/15/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Weiss, Yizhar, Velger, Mordekhai, Natan-Knaz, Sivan, Erlich, Raviv, Sromin, Alexander
• Primary Examiner(s): CHERRY, EUNCHA P
• Application Number:
  US14/298,925
• Publication Number:
  US 20140327945A1
• Time in Patent Office: 667 Days
• Field of Search: 3592161-2181
• US Class Current: 1/1
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G02B 26/121 Mechanical drive devices for polygonal mirrors
• CPC Class Codes: H04N 3/08 having a moving reflector
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine
• CPC Class Codes: Y10T 29/49012 Rotor

Abstract

A method of scanning a light beam is disclosed. The method comprises scanning the light beam along a first axis and scanning the light beam along a second axis, such that a functional dependence of the scanning along the first axis is substantially a step-wave, and a functional dependence of the scanning along the second axis is other than a step-wave.

Claims

1. A scanning device, comprising:

a micromirror;

a rotor, which comprises a magnetic material attached to the micromirror; and

a stator assembly, which comprises;

a core having an air gap, which contains at least a portion of the micromirror and the magnetic material; and

a coil arrangement comprising a conductive wire wound on the core so as to cause the core to form a magnetic circuit through the air gap in response to an electrical current flowing in the conductive wire, so that the rotor and the micromirror move in response to the magnetic circuit.

2. The device according to claim 1, wherein the core with the air gap defines a closed shape with two opposing poles respectively positioned on a first side and a second side of the air gap.

3. the device according to claim 2, wherein the closed shape comprises at least four sides, of which one side is interrupted by the air gap.

4. The device according to claim 3, wherein the conductive wire is wound on two of the sides of the core, thereby defining two coils on the core.

5. The device according to claim 4, wherein the micromirror comprises a reflective surface and elongated wings connected thereto, such that the magnetic circuit applies a predetermined moment to the elongated wings, thereby causing the reflective surface to rotate about the axis.

6. The device according to claim 5, wherein the magnetic material is attached to the elongated wings, and at least one of the elongated wings is positioned between the two opposing poles.

7. The device according to claim 1, wherein the magnetic material has a magnetization vector having a component that is perpendicular to a magnetic field of the magnetic circuit in the air gap, thereby causing the rotor to rotate about an axis perpendicular to both the component of the magnetic field and the magnetization vector.

8. The device according to claim 7, wherein the micromirror has a shape selected so as to minimize a moment of inertia of the micromirror with respect to the axis.

9. The device according to claim 1, and comprising a substrate formed with at least one cavity, wherein the stator assembly is positioned in the at least one cavity.

10. The device according to claim 1, wherein the micromirror comprises a plurality of ribs.

11. The device according to claim 1, wherein the electrical current is configured so as to cause the micromirror to scan a light beam a raster pattern.

12. the device according to claim 11, wherein the raster pattern comprises an interlaced scan along a first axis.

13. A LIDAR system, comprising a scanning device according to claim 1.

14. A display system, comprising a scanning device according to claim 1 for projecting a light beam onto a displaying object.

15. A method for manufacturing a scanning device, comprising:

patterning and etching a substrate so as to provide a micromirror;

attaching a permanent magnetic material to the micromirror;

providing a core having an air gap;

winding a conductive coil around the core so as to cause the core to form a magnetic circuit through the air gap in response to an electrical current flowing in the conductive coil; and

positioning at least a portion of the micromirror and the permanent magnetic material in the air gap so that the micromirror moves in response to the electrical current.

16. The method according to claim 15, wherein the micromirror comprises a reflective surface and elongated wings connected thereto, wherein the magnetic material is attached to the elongated wings, and at least one of the elongated wings is positioned in the air gap.

17. The method according to claim 16, wherein the core with the air gap defines a closed shape with two opposing poles respectively positioned on a first side and a second side of the air gap, and wherein the at least one of the elongated wings is positioned between the two opposing poles.

18. The method according to claim 17, wherein the forming the coil comprises winding a conductive wire so as to define two coils on the core.

19. The method according to claim 15, wherein the magnetic material has a magnetization vector having a component that is perpendicular to a magnetic field of the magnetic circuit in the air gap, and wherein the method comprises providing the electrical current so as to cause the micromirror to rotate about an axis perpendicular to both the magnetic field and the component of the magnetization vector.

20. The method according to claim 15, wherein providing the electrical current comprises driving the micromirror to scan a light beam a raster pattern.