Autofocus for folded optic array cameras

• US 9,549,107 B2
• Filed: 06/17/2015
• Issued: 01/17/2017
• Est. Priority Date: 06/20/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Georgiev, Todor Georgiev
• Primary Examiner(s): BERARDESCA, PAUL M
• Application Number:
  US14/742,017
• Publication Number:
  US 20150373252A1
• Time in Patent Office: 580 Days
• US Class Current: 1/1
• CPC Class Codes: G03B 13/36 Autofocus systems
• CPC Class Codes: G03B 17/17 with reflectors arranged in beam forming the photographic image, e.g. for reducing dimensions of camera
• CPC Class Codes: G03B 2205/0069 using electromagnetic actuators, e.g. voice coils
• CPC Class Codes: G03B 3/06 using movable reflectors to alter length of light path
• CPC Class Codes: H04N 23/45 for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images
• CPC Class Codes: H04N 23/54 Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/57 Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices
• CPC Class Codes: H04N 23/58 Means for changing the camera field of view without moving the camera body, e.g. nutating or panning of optics or image sensors
• CPC Class Codes: H04N 23/67 Focus control based on electronic image sensor signals
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 23/75 by influencing optical camera components

Abstract

Aspects relate to autofocus systems and techniques for an array camera having a low-profile height, for example approximately 4 mm. A voice coil motor (VCM) can be positioned proximate to a folded optic assembly in the array camera to enable vertical motion of a second light directing surface for changing the focal position of the corresponding sensor. A driving member can be positioned within the coil of the VCM to provide vertical movement, and the driving member can be coupled to the second light directing surface, for example by a lever. Accordingly, the movement of the VCM driving member can be transferred to the second light directing surface across a distance, providing autofocus capabilities without increasing the overall height of the array camera.

Claims

1. An autofocus module for a folded optic array camera, comprising:

a folded optic assembly including

an image sensor mounted to a substrate, the substrate defining a first plane;

a first reflective surface; and

a second reflective surface, the first reflective surface positioned to receive light representing a portion of a scene and reflect the light toward the second reflective surface, and the second reflective surface positioned to receive the light from the first reflective surface and reflect the light toward the image sensor;

an actuator mounted to the substrate and including a driving member positioned for movement in a direction orthogonal to the plane of the substrate;

a lever in contact with the driving member and second reflective surface such that the movement of the driving member is transferred to the second reflective surface via the lever; and

a counterweight coupled to a first end of the lever, wherein the driving member is coupled to a middle portion of the lever and the second reflective surface is coupled to a second end of the lever.

2. The autofocus module of claim 1, wherein the actuator comprises a voice coil motor.

3. The autofocus module of claim 2, wherein the driving member is threaded within a coil of the voice coil motor.

4. The autofocus module of claim 1, wherein the movement in the direction orthogonal to the substantially horizontal plane is within a range of approximately 120 microns to approximately 150 microns.

5. The autofocus module of claim 1, further comprising a lens assembly positioned between the first reflective surface and the second reflective surface.

6. The autofocus module of claim 5, wherein a diameter of the lens assembly is approximately 4 mm.

7. The autofocus module of claim 1, wherein a weight of the counterweight is selected to at least partially balance a weight of the second reflective surface.

8. The autofocus module of claim 7, wherein the second reflective surface comprises one of a reflective mirror and a prism.

11. The autofocus module of claim 1, wherein a first end of the lever is coupled to a structure forming the first reflective surface, and wherein the second reflective surface is coupled to a middle portion of the lever and the driving member is coupled to a second end of the lever.

9. An autofocus module for a folded optic array camera, comprising:

a folded optic assembly including

an image sensor mounted to a substrate, the substrate defining a first plane;

a first reflective surface; and

a second reflective surface, the first reflective surface positioned to receive light representing a portion of a scene and reflect the light toward the second reflective surface, and the second reflective surface positioned to receive the light from the first reflective surface and reflect the light toward the image sensor;

an actuator mounted to the substrate and including a driving member positioned for movement in a direction orthogonal to the plane of the substrate; and

a lever in contact with the driving member and second reflective surface such that the movement of the driving member is transferred to the second reflective surface via the lever, and

a strut coupled to a first end of the lever using a hinge,

wherein the lever comprises a first end coupled to the driving member and a second end coupled to the structure comprising the additional reflective surface via one or both of a strut and a hinge, wherein a middle portion of the lever is coupled to the reflective surface.

10. The autofocus module of claim 9, wherein the strut is coupled to a structure forming the first reflective surface, and wherein the second reflective is coupled to a middle portion of the lever and the driving member is coupled to a second end of the lever.

25. The autofocus module of claim 9, wherein the driving member is coupled to a middle portion of the lever and the second reflective surface is coupled to a second end of the lever.

12. A method for capturing an image of a target image scene using a folded optic array camera comprising a plurality of folded optic assemblies mounted to a substrate defining a first plane and positioned around a structure providing a corresponding plurality of light folding surfaces, the method comprising:

for each of the plurality of folded optic assemblies;

causing movement of a driving member of an actuator in a direction orthogonal to the plane of the substrate;

transferring the movement of the driving member to a second light directing surface, thereby changing a focal distance of light representing a portion of the target image scene, the corresponding light folding surface of the plurality of light folding surfaces positioned to direct the light toward the second light directing surface and the second light directing surface positioned to direct the light toward an image sensor; and

capturing an image representing the portion of the light using the image sensor.

13. The method of claim 12, wherein transferring the movement is accomplished by a lever in contact with the driving member and second light directing surface.

14. The method of claim 12, further comprising keeping each of the plurality of folded optic assemblies focused at approximately the same distance.

15. The method of claim 14, further comprising determining an amount of movement for a selected driver assembly of the plurality of folded optic assemblies and using the amount of movement for the selected driver assembly to determine movement for each of the other of the plurality of folded optic assemblies.

16. The method of claim 15, wherein determining movement for each of the other of the plurality of folded optic assemblies is based at least partly on the amount of movement for the selected driver assembly and at least partly on one or more coefficients defining a relationship between the plurality of folded optic assemblies.

17. The method of claim 12, further comprising performing a stitching operation on the image representing the portion of the light from each of the plurality of folded optic assemblies to form the image of the target image scene.

18. An autofocus module for a folded optic array camera, comprising:

an image sensor defining a first plane, the image sensor configured to receive light representing at least a portion of a target image scene;

a lens assembly configured to focus the light, the lens assembly having an optical axis;

a reflective surface positioned between the lens assembly and the image sensor to reflect the light received from the lens assembly onto the image sensor;

an actuator comprising a driving member positioned for movement in a direction perpendicular to the optical axis of the lens assembly;

a lever coupled to the driving member and the reflective surface to transfer movement of the driving member to the reflective surface in the direction perpendicular to the optical axis for changing an optical path length of the light; and

a counterweight coupled to a first end of the lever, wherein a middle portion of the lever coupled to the driving member and a second end of the lever coupled to the second reflective surface.

19. The autofocus module of claim 18, wherein the lens assembly is positioned so that the optical axis runs substantially parallel to the first plane.

20. The autofocus module of claim 18, further comprising a strut coupled to a first end of the lever, a middle portion of the lever coupled to the driving member and a second end of the lever coupled to the reflective surface.

21. The autofocus module of claim 18, further comprising a plurality of cameras, a first camera of the plurality of cameras comprising the autofocus module comprising the folded optic assembly, the actuator, and the lever.

22. An autofocus module for a folded optic array camera, comprising:

an image sensor mounted to a substrate defining a first plane;

a first light directing surface;

a second light directing surface, the first light directing surface positioned to direct light representing a portion of a target image scene toward second light directing surface, and the second light directing surface positioned to direct the light toward the image sensor;

an actuator mounted to the substrate and including a driving member positioned for movement in a direction orthogonal to the plane of the substrate; and

a lever in contact with the driving member and second light directing surface such that the movement of the driving member is transferred to the second light directing surface via the lever, wherein the movement in the direction orthogonal to the substantially horizontal plane is within a range of approximately 120 microns to approximately 150 microns.

23. The autofocus module of claim 22, further comprising a counterweight coupled to a first end of the lever, wherein the driving member is coupled to a middle portion of the lever and the second light directing surface is coupled to a second end of the lever.

24. The autofocus module of claim 22, further comprising a strut coupled to a first end of the lever using a hinge, wherein the driving member is coupled to a middle portion of the lever and the second light directing surface is coupled to a second end of the lever.

26. An autofocus module for a folded optic array camera, comprising:

an image sensor defining a first plane, the image sensor configured to receive light representing at least a portion of a target image scene;

a lens assembly configured to focus the light, the lens assembly having an optical axis;

reflective surface positioned between the lens assembly and the image sensor to reflect the light received from the lens assembly onto the image sensor;

an actuator comprising a driving member positioned for movement in a direction perpendicular to the optical axis of the lens assembly; and

means for transferring the movement of the driving member to the reflective surface in the direction perpendicular to the optical axis for changing an optical path length of the light,

wherein the lever comprises a first end coupled to the driving member and a second end coupled to the structure comprising the additional reflective surface via one or both of a strut and a hinge, wherein a middle portion of the lever is coupled to the reflective surface.