Methods and devices for thin camera focusing alignment

Patent metadata

Field	Value
Publication number	US-2016356978-A1
Application number	US-201514731303-A
Country	US
Kind code	A1
Filing date	Jun 4, 2015
Priority date	Jun 4, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

Methods and devices are disclosed for aligning a lens assembly and a sensor assembly of an optical system during assembly of the optical system. For example, one method includes positioning the sensor assembly, having at least an image sensor, at the focal plane of the lens assembly and directing light through an alignment optic and lens assembly onto the image sensor. The method further includes producing multiple images from the light received through the lens assembly and alignment optic, the images having multiple alignment features based on the light received through the alignment optic, and the alignment features having multiple sections. The method then measures at least one performance indicator corresponding to each of multiple sections, and adjusts the position of the image sensor based on an optimization of the performance indicators, while the sensor assembly is being attached to the lens assembly.

First claim

What is claimed is:

1 . A method for aligning an optical system during assembly, the optical system having at least a lens assembly and a sensor assembly, the method comprising:
positioning a sensor assembly at the focal plane of a lens assembly, the sensor assembly including an image sensor; directing light through an alignment optic and lens assembly onto the image sensor; producing a plurality of images from the light received through the lens assembly and alignment optic, the images having a plurality of alignment features based on the light received through the alignment optic, and the alignment features having a plurality of sections; measuring at least one performance indicator corresponding to each of the plurality of sections; and adjusting the position of the image sensor, based on an optimization of the performance indicators, while the sensor assembly is being attached to the lens assembly.

2 . The method of claim 1 , wherein the sensor assembly includes the image sensor and a sensor cover, and at least one surface of the lens assembly is attached to the sensor cover.

3 . The method of claim 1 , wherein the performance indicator is a sharpness value corresponding to the intensity of the light along the sections of the alignment features detected by a portion of the image sensor.

4 . The method of claim 1 , wherein the light directed through the lens assembly and alignment optic is collimated light.

5 . The method claim 1 , wherein the alignment optic is a multi-zone flat top axicon lens.

6 . The method of claim 1 , wherein light directed through the alignment optic is segmented by the alignment optic into alignment features depicted as a plurality of concentric rings, wherein each alignment feature corresponds to at least one ring of the plurality of concentric rings.

7 . The method of claim 6 , wherein the plurality of concentric rings includes at least a first concentric ring and at least a second concentric ring, wherein the first concentric ring has a radius that is smaller than the second concentric ring.

8 . The method of claim 7 , wherein the performance indicators corresponding to sections of the first concentric ring relate to the translational position of the sensor assembly along the optical axis.

9 . The method of claim 7 , wherein the performance indicators corresponding to sections of at least one concentric ring relate to the rotational position of the image sensor in relation to the focal plane of the lens assembly.

10 . The method of claim 1 , wherein each of the plurality of alignment images corresponds to a different position of the image sensor relative to the lens assembly.

11 . The method of claim 7 , wherein said adjusting the sensor assembly further comprises, maximizing the at least one performance indicator based on a translational position adjustment of the sensor assembly, wherein the performance indicator is maximized when the performance indicator of at all sections of the first alignment feature are at a maximum.

12 . The method of claim 7 , wherein said adjusting the sensor assembly further comprises, balancing the at least one performance indicator based on the rotational position adjustment of the sensor assembly, wherein the performance indicator is balanced when the at least one performance indicator of at least a first section of at least one alignment feature is substantially similar to the at least one performance indicator of at least a second section of the same alignment feature.

13 . The method of claim 7 , wherein said adjusting the sensor assembly further comprises, optimizing the at least one performance indicator based on the rotational position adjustment of the sensor assembly, wherein the at least one performance indicator is optimized when the at least one performance indicator of the at least one section of at least one alignment feature is substantially similar to the performance indicator of the sections of alignment features positioned within the at least one alignment feature, and vice versa.

14 . A device for aligning an optical system, having a lens assembly and a sensor assembly, during attachment, comprising:
a lens assembly holder, configured to move the lens assembly and support an alignment optic, wherein the alignment optic is orientated along the optical axis of the lens assembly; a sensor assembly holder, configured to move the sensor assembly, the sensor assembly having an image sensor; an attachment mechanism, configured to attach the lens assembly to the sensor assembly when substantially aligned with respect to each other; a light source, configured to direct light through the alignment optic and lens assembly onto the image sensor; a processor, operably coupled to the lens assembly holder and sensor assembly holder; and a memory component, operably coupled to the processor, the processor and the memory component collectively configured to:
capture a plurality of images from the light received by the sensor assembly through the lens assembly and alignment optic;
determine a plurality of alignment features based on the light received through the alignment optic;
determine a plurality of substantially linear sections for each alignment feature;
measure at least one performance indicator corresponding to each of the plurality of substantially linear sections; and
determine an adjustment of the sensor assembly, relative to the lens assembly, based on optimizing the performance indicators.

15 . The device of claim 14 , wherein the sensor assembly includes the image sensor and a sensor cover and at least one surface of the lens assembly is attached to the sensor cover.

16 . The device of claim 14 , wherein the performance indicator is a sharpness value corresponding to the intensity of the light along the substantially linear sections of the alignment features detected by a portion of the image sensor.

17 . The device of claim 14 , wherein the light directed through the lens assembly and alignment optic is collimated light.

18 . The device claim 14 , wherein the alignment optic is a multi-zone flat top axicon lens.

19 . The device claim 14 , wherein the light is segmented by the alignment optic into alignment features depicted as a plurality of concentric rings, wherein each alignment feature corresponds to at least one ring of the plurality of concentric rings.

20 . The device of claim 19 , wherein the plurality of concentric rings includes at least an first concentric ring and at least a second concentric ring, wherein the first concentric ring has a radius that is smaller than the second concentric ring.

21 . The device of claim 20 , wherein the performance indicators corresponding to substantially linear sections of the first concentric ring relate to the translational position of the sensor assembly along the optical axis.

22 . The device of claim 20 , wherein the performance indicators corresponding to substantially linear sections of at least one concentric ring relate to the rotational position of the image sensor in relation to the focal plane of the lens assembly.

23 . The device claim 14 , wherein each of the plurality of alignment images corresponds to a different position of the image sensor relative to the lens assembly.

24 . The device of claim 20 , wherein the sensor assembly holder is further configured to:
adjust the position of the sensor assembly; and maximize the at least one perfor

Assignees

• Qualcomm Inc

Inventors

• Osborne Thomas Wesley

Classifications

• H04N23/673

  based on contrast or high frequency components of image signals, e.g. hill climbing method · CPC title

• G02B27/62

  Optical apparatus specially adapted for adjusting optical elements during the assembly of optical systems · CPC title

• G02B7/004 Primary

  Manual alignment, e.g. micromanipulators · CPC title

• G02B7/025

  using glue · CPC title

• G06T7/0004

  Industrial image inspection · CPC title