Capacative auto focus position detection

Patent metadata

Field	Value
Publication number	US-9736345-B1
Application number	US-201514803951-A
Country	US
Kind code	B1
Filing date	Jul 20, 2015
Priority date	Jul 20, 2015
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

Some embodiments include an electrically conductive capacitor plate mounted to a chassis supporting an actuator using one or more suspension wires. In some embodiments, the first electrically conductive capacitor plate is electrically connected with an electrically conductive coil of the actuator. Some embodiments include the electrically conductive coil. In some embodiments, a capacitance between the first electrically conductive capacitor plate and the electrically conductive coil varies as function of the position of the electrically conductive coil relative to the first electrically conductive capacitor plate.

First claim

What is claimed is:

1. A camera of a mobile computing device having a position sensor for a lens of the camera, the sensor comprising:
a first electrically conductive capacitor plate mounted to a yoke, wherein
the yoke supports a lens carriage,
the yoke is attached to a chassis using one or more suspension wires,
the first electrically conductive capacitor plate is electrically connected through the one or more suspension wires, and
an electrically conductive autofocus coil of an autofocus actuator mechanism for moving a lens carriage is electrically connected through the one or more suspension wires; and

the electrically conductive autofocus coil of the autofocus actuator mechanism for moving the lens carriage, wherein
a capacitance between the first electrically conductive capacitor plate and the autofocus coil varies as function of the position of the autofocus coil relative to the first electrically conductive capacitor plate.

2. The camera of claim 1 , further comprising
a voltage source capable of delivering an impulse alternating electrical signal to the autofocus coil, and
a measurement circuit for measuring a resonant frequency of a resonant inductance-capacitance circuit comprising the autofocus coil and the first capacitor plate in response to the impulse.

3. The camera of claim 1 , further comprising
position measurement logic for measuring the position of the lens carriage relative to the chassis by
applying an alternating electrical signal to the autofocus coil, and
measuring a resonant frequency of a resonant inductance-capacitance circuit comprising the autofocus coil and the first capacitor plate.

4. The camera of claim 1 , further comprising
a second electrically conductive capacitor plate is mounted to the yoke, wherein
the second electrically conductive capacitor plate is mounted at a position along an optical axis of the camera different from a position along an optical axis of the camera from the first electrically conductive capacitor plate, and
the second electrically conductive capacitor plate is electrically connected using the one or more suspension wires.

5. The camera of claim 1 , wherein
the first electrically conductive capacitor plate is mounted to the yoke mounted to the chassis of the lens carriage using one or more suspension wires using a plastic isolation component fabricated with laser direct structuring between the first electrically conductive capacitor plate and the chassis of the lens carriage.

6. The camera of claim 1 , wherein
the first electrically conductive capacitor plate is mounted to the yoke mounted to the chassis of the lens carriage using one or more suspension wires using a flexible printed circuit situated between the first electrically conductive capacitor plate and the chassis of the lens carriage.

7. The camera of claim 1 , wherein
the second electrically conductive capacitor plate is mounted to autofocus coil using a flexible printed circuit situated between the second electrically conductive capacitor plate and the autofocus coil.

8. A position sensor, comprising:
a first electrically conductive capacitor plate mounted to an actuator supported by one or more suspension wires, wherein
the first electrically conductive capacitor plate is electrically connected through the one or more suspension wires with an electrically conductive coil of the actuator; and

the electrically conductive coil, wherein
a capacitance between the first electrically conductive capacitor plate and the electrically conductive coil varies as function of the position of the electrically conductive coil relative to the first electrically conductive capacitor plate.

9. The position sensor of claim 8 , further comprising
a voltage source capable of delivering an impulse alternating electrical signal to the coil; and
a second capacitor plate mounted to the electrically conductive coil, wherein the capacitance between the first electrically conductive capacitor plate and the electrically conductive coil comprises a capacitance between the first electrically conductive capacitor plate and the second capacitor plate.

10. The position sensor of claim 8 , further comprising
a measurement circuit for measuring a resonant frequency of a resonant inductance-capacitance circuit comprising the coil and the first capacitor plate in response to the impulse.

11. The position sensor of claim 8 , further comprising
position measurement logic for measuring the position of coil the chassis by
applying an alternating electrical signal to the coil, and
measuring a resonant frequency of a resonant inductance-capacitance circuit comprising the coil and the first capacitor plate.

12. The position sensor of claim 8 , further comprising
a second electrically conductive capacitor plate mounted to the yoke mounted to the chassis of the lens carriage using one or more suspension wires,
wherein
the second electrically conductive capacitor plate is mounted at a position along a z axis through a center of the coil different from a position along the z axis from the first electrically conductive capacitor plate, and
the second electrically conductive capacitor plate is electrically connected in parallel with the coil.

13. The position sensor of claim 8 , wherein
the first electrically conductive capacitor plate is mounted to the chassis using a plastic isolation component fabricated with laser direct structuring between the first electrically conductive capacitor plate and the chassis of the lens carriage.

Assignees

• Apple Inc

Inventors

• Topliss Richard J
• Tsai Richard H

Classifications

• G02B7/08 Primary

  adapted to co-operate with a remote control mechanism · CPC title

• H04N23/687

  by shifting the lens or sensor position · CPC title

• H04N23/54 Primary

  Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils · CPC title

• H04N23/57

  Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices · CPC title

• H04N23/67

  Focus control based on electronic image sensor signals · CPC title