Tri-axis close loop feedback controlling module for electromagnetic lens driving device

Patent metadata

Field	Value
Publication number	US-10168506-B2
Application number	US-201615226043-A
Country	US
Kind code	B2
Filing date	Aug 2, 2016
Priority date	May 6, 2013
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

The tri-axis close-loop feedback controlling module for electromagnetic lens driving device includes a 6-pin Hall element. Two pins of the Hall element are coupled to an auto-focus module for providing a current to drive the auto-focus module to conduct auto-focusing operations along the Z-axis; while other four pins of the Hall element are coupled to a control unit. The control unit detects the X-Y axial positions of the auto-focus module relative to an OIS module and generates a control signal which is then sent to the Hall element. Therefore, the Hall element not only can provide its own feedback controlling function according to the Z-axial position of lens, but also can drive the auto-focus module based on the control signal corresponding to the X-Y axial positions of the auto-focus module, so as to achieve the goal of tri-axis close-loop feedback controlling for the electromagnetic lens driving device.

First claim

What is claimed is:

1. An electromagnetic lens driving device, comprising:
a lens holder for holding a lens;
a movable frame for receiving the lens holder in such a manner that the lens holder is movable relative to the movable frame along a Z-axis direction;
a first spring plate having one end connected to the lens holder and the other end connected to the movable frame;
a second spring plate having one end connected to the lens holder and the other end connected to the movable frame, wherein the lens holder is flexibly suspended in a receiving space of the movable frame by the first spring plate and the second spring plate;
an electromagnetic driving module, furnished between the movable frame and the lens holder for driving the lens holder to move within the movable frame along the Z-axis direction;
a first circuit board, wherein the movable frame is suspended above the first circuit board by a plurality of suspension wires;
an optical image stabilization (OIS) module for driving the movable frame together with the lens holder to perform bi-directional movements along a X-axis direction and a Y-axis direction, wherein the X-axis, the Y-axis, and the Z-axis are perpendicular to each other;
the first spring plate includes at least six independent and separated first spring members, wherein each one of the first spring members of the first spring plate comprises: a first outer rim connected to the movable frame, a first inner rim connected to the lens holder, and at least one first inner string extending and connecting between the first outer rim and the first inner rim; and
a Hall element furnished within the movable frame and having at least six pins, wherein two of the pins are coupled with a driving coil of the electromagnetic driving module by two of the first spring members of the first spring plate, and other four of the pins are coupled with other four of the first spring members of the first spring plate and coupled with the first circuit board by a suspension mechanism composed of the suspension wires.

2. The electromagnetic lens driving device as claimed in claim 1 , further comprising:
a control unit furnished on the first circuit board and coupled with the OIS module for detecting and controlling operation of the OIS module as well as for generating a control signal according to the operation of the OIS module, wherein two of the pins of the Hall element supply a current to the driving coil of the electromagnetic driving module in order to control operation of the electromagnetic driving module, and other four pins of the Hall element are further coupled with the control unit on the first circuit board for receiving the control signal from the control unit in order to control the current supplied to the electromagnetic driving module based on the control signal, so as to achieve a function of tri-axis close-loop feedback controlling the electromagnetic driving module.

3. The electromagnetic lens driving device as claimed in claim 2 , further comprising a second circuit board connected to the movable frame, the Hall element being furnished on the second circuit board, and a sensing magnet for Z-axis position furnished on the lens holder at a location corresponding to the Hall element.

4. The electromagnetic lens driving device as claimed in claim 3 , wherein the first spring plate is in the form of hollowed out thin metal plate in addition, the four first spring members of the first spring plate which are coupled with the control unit on the first circuit board by the suspension wires, respectively, further comprise a first contact located on the first outer rim thereof, and each one of the suspension wires has its one end being correspondingly connected to one of the first contacts, coupled to the second circuit board, and further coupled to one of the pins of the Hall element; the other two first spring members of the first spring plate, respectively, is coupled with the driving coil of the electromagnetic driving module by the first inner rim thereof, and the first outer rim of each one of the other two spring members is coupled to the second circuit board and is further coupled to one of the pins of the Hall element in order to supply the current to the electromagnetic driving module so as to control the operation of the electromagnetic driving module.

5. The electromagnetic lens driving device as claimed in claim 2 , wherein the OIS module comprises: at least a first stabilizing coil furnished on first circuit board and coupled to the control unit; at least a second stabilizing coil furnished on the first circuit board and being perpendicular to the first stabilizing coil, and the second stabilizing coil are coupled to the control unit; at least a first stabilizing magnet mounted on the movable frame and corresponding to the first stabilizing coil; at least a second stabilizing magnet mounted on the movable frame and corresponding to the second stabilizing coil; and at least two position sensors mounted on the first circuit board and coupled to the control unit for detecting the position of the movable frame relative to the first circuit board along the X-axis direction and the Y-axis direction.

6. The electromagnetic lens driving device as claimed in claim 5 , wherein the electromagnetic driving module comprises the driving coil furnished on the lens holder and at least two driving magnets mounted on the movable frame and corresponding to the driving coil, and wherein the first and second stabilizing magnets of the OIS module are the same with the driving magnets of the electromagnetic driving module.

Assignees

• Tdk Taiwan Corp

Inventors

• Chen Shu-Shan
• Hu Chao-Chang
• Lin Wen-Chang

Classifications

• H04N23/687

  by shifting the lens or sensor position · CPC title

• G02B13/001 Primary

  Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras (G02B23/243 takes precedence) · CPC title

• G03B13/36

  Autofocus systems · CPC title

• G02B7/08

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

• G02B27/646 Primary

  compensating for small deviations, e.g. due to vibration or shake (movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68) · CPC title