Bi-directional stiffness for optical image stabilization in a dual-aperture digital camera

• US 10,379,371 B2
• Filed: 06/25/2018
• Issued: 08/13/2019
• Est. Priority Date: 05/28/2015
• Status: Active Grant

• Current Assignee: Corephotonics Ltd. (Samsung Electronics Co. Ltd.)
• Original Assignee: Corephotonics Ltd. (Samsung Electronics Co. Ltd.)
• Inventors: Avivi, Gal, Jerby, Itay
• Primary Examiner(s): Chapel, Derek S.
• Application Number:
  US16/017,144
• Publication Number:
  US 20180307057A1
• Time in Patent Office: 414 Days
• Field of Search: None
• CPC Class Codes: G02B 27/64 Imaging systems using optical elements for stabilisation of the lateral and angular position of the image
• CPC Class Codes: G02B 27/646 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 Class Codes: G02B 7/04 with mechanism for focusing or varying magnification
• CPC Class Codes: G02B 7/08 adapted to co-operate with a remote control mechanism
• CPC Class Codes: G02B 7/09 adapted for automatic focusing or varying magnification
• 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 23/55 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 23/687 by shifting the lens or sensor position

Abstract

Mechanisms for providing optical image stabilization in at least one direction as well as auto-focus in a digital camera comprise a plurality of springs mechanically coupled to at least a lens module carrying a lens of the digital camera, wherein the plurality of springs provides overall low stiffness to movement of the lens in two, first and second directions orthogonal to each other, and provides high stiffness to torsion of the lens module.

Claims

1. A mechanism for providing optical image stabilization (OIS) in a digital camera, comprising:

a first plurality of springs connected at a lower end to a base and at an upper end to a rigid upper frame, the first plurality of springs enabling the rigid upper frame to move with a first stiffness in a first direction and to move with a second stiffness, higher than the first stiffness, in a second direction orthogonal to the first direction; and

a second plurality of springs connected at an upper end to the rigid upper frame and at the lower end to a rigid body that includes a lens having a lens optical axis, the second plurality of springs enabling the lens to move with a third stiffness in the second direction and to move with a fourth stiffness, higher than the third stiffness, in the first direction,

wherein the upper ends and the lower ends of both pluralities of springs define a same direction, wherein the first direction is substantially parallel to the lens optical axis and

wherein the mechanism enables lens movement in the first and second directions and reduces rotation about an axis perpendicular to the first and second direction.

2. The mechanism of claim 1, wherein normalized natural frequencies for the first direction and second direction are of the same first order of magnitude and wherein a normalized natural frequency for rotation has a value which is greater by at least one order of magnitude than the first order of magnitude.

3. The mechanism of claim 1, wherein a ratio between a natural frequency for rotation and either of the natural frequencies for movement in the first direction and the second direction is greater than 2.

4. The mechanism of claim 1, wherein a ratio between a natural frequency for rotation and either of the natural frequencies for movement in the first direction and the second direction is greater than 5.

5. The mechanism of claim 1, wherein a ratio between a natural frequency for rotation and either of the natural frequencies for movement in the first direction and the second direction is greater than 10.

6. The mechanism of claim 5, wherein the lens movements in the first direction and the second direction are characterized by natural frequencies in the range of 30-100 Hz and wherein the lens rotation about an axis perpendicular to the first direction and the second direction is characterized by a natural frequency in the range of 200-4000 Hz.

7. The mechanism of claim 1, dimensioned to accommodate the lens without obstructing an optical path passing through the lens.

8. The mechanism of claim 1, wherein the first plurality of springs or the second plurality of springs includes a pair of cross springs.

9. The mechanism of claim 1, wherein the first plurality of springs and the second plurality of springs includes a mix of leaf springs and cross springs.

10. The mechanism of claim 1, wherein the first plurality of springs includes two pairs of leaf springs and wherein the second plurality of springs includes a pair of cross springs.

11. The mechanism of claim 1, wherein the first plurality of springs includes a pair of leaf springs and one cross spring and wherein the second plurality of springs includes a pair of cross springs.

12. The mechanism of claim 1, wherein each of the first and second pluralities of springs includes a pair of cross springs.

13. The mechanism of claim 1, wherein the digital camera is a dual-optical module camera.

14. The mechanism of claim 13, wherein the second plurality of springs is connected at the upper end to the rigid upper frame and at the lower end through a support structure to two lenses of the dual-optical module camera.

15. The mechanism of claim 1, wherein the lens is a folded lens.

16. The mechanism of claim 1, adapted to perform auto-focus.

17. The mechanism of claim 1, wherein the second stiffness is greater than the first stiffness by at least 4 times and wherein the fourth stiffness is greater than the third stiffness by at least 4 times.

18. The mechanism of claim 1, wherein each spring of the first plurality of springs has a rectangular cross section with 20-60 μ

m thickness in the first direction, and wherein each spring of the second plurality of springs has a rectangular cross section with 20-60 μ

m thickness in the second direction.