WO2012161802A2

WO2012161802A2 - Autofocus camera module packaging with circuitry-integrated actuator system

Info

Publication number: WO2012161802A2
Application number: PCT/US2012/026585
Authority: WO
Inventors: Prebesh PAVITHRAN; Yeow Thiam Ooi; Hung Khin WONG; Haw Chyn Cheng; Khen Ming GOH
Original assignee: Flextronics AP LLC
Current assignee: Flextronics AP LLC
Priority date: 2011-02-24
Filing date: 2012-02-24
Publication date: 2012-11-29
Anticipated expiration: 2013-08-24
Also published as: US10009528B2; WO2012161802A3; US20120218449A1

Abstract

A camera module with no PCB that instead has a lens actuator/housing that has circuitry on a bottom surface thereof for direct electrical connection to a mobile electronic device. The housing further has a recess formed in the bottom surface thereof to receive an image sensor. The circuitry is three-dimensional in that it includes a first set of contact pads on one planar surface for connection to the mobile electronic device, a second set of contact pads on a planar surface within the recess for connection to the image sensor, and conductive traces that connect each of the contact pads of the first set with an associated one of the contact pads of the second set by having the trace follow a path from the first planar surface, along a intersecting third planar surface to the second planar surface.

Description

AUTOFOCUS CAMERA MODULE PACKAGING WITH CIRCUITRY- INTEGRATED ACTUATOR SYSTEM

Cross Reference

[0001] This application is the non-provisional of U.S. Provisional Pat. Appl. No.

61/446,156, filed February 24, 2011 , entitled "AUTOFOCUS CAMERA MODULE PACKAGING WITH CIRCUITRY-INTEGRATED ACTUATOR SYSTEM," which is hereby incorporated by reference into this application.

Background

[0002] Digital camera modules are currently being incorporated into a variety of host devices such as, for example, cellular telephones, personal data assistants (PDSs), computers, etc. Such host devices are becoming increasingly more compact and, therefore, permitting less and less space for camera module form factors. Accordingly, host device manufacturers prefer digital camera modules to be small, so that they can be incorporated into the host device without increasing the overall size of the host device. Of course, host device manufacturers also prefer camera modules that capture images of the highest possible quality.

Therefore, the goal in designing and manufacturing camera modules is to minimize size and maximize image quality capabilities.

[0003] A conventional digital camera module generally includes an integrated image capture device (ICD), passive components, a printed circuit board (PCB), an autofocus actuator, a lens, and a housing. Typically, the ICD, passive

components, and autofocus actuator are mounted on the top of PCB. Further, the lens is coupled to the autofocus actuator and the housing is attached to the PCB so that ICD, passive components, and autofocus actuator are covered by the bottom of the housing. The top of the housing typically includes an optical opening that exposes the lens. The bottom surface of the PCB typically includes a plurality of electrical contacts that provide a means for electrically connecting the camera module to a host device.

[0004] One problem with conventional camera module designs is that they have a relatively large footprint and, therefore, occupy a significant amount of real-estate area on the host device. This is because the housing has to be large enough to cover the image sensor, the electrical components, the autofocus actuator, and the lens,

[0005] Another problem is that conventional camera modules have an overall complex assembly and mechanical stack-up of components which, consequently, lead to other problems. For example, the high overall height of conventional camera modules limits how thin the host devices can be made. As another example, the lens is indirectly coupled to the image sensor through a stack-up of several intermediate components such that an undesirable amount of optical tilt may exist in the camera module. Of course, optical tilt between the Sens and the image sensor is a well known problem that is extremely difficult to minimize and can substantially reduce the image quality of a camera module. As another example, the design stage for conventional camera modules is long because it requires arranging multiple electrical components (e.g., IC chips, resistors, capacitors, etc.) on a substrate that has limited available real estate,

[0006] It is against this background that a simplified camera module design has been developed, specifically a shorter camera module that reduces optical tilt.

Summary

[0007] A camera module for attachment to a mobile electronic device includes a housing having a bottom surface on which electrical circuitry is formed thereon, the circuitry including a first set of contact pads for direct electrical connection to the mobile electronic device and also including a second set of contact pads; a lens received within the housing; and an image sensor electrically and mechanically connected to the housing via the second set of contact pads.

[0008] The electrical circuitry on the bottom surface may include three-dimensional circuitry. The electrical circuitry on the bottom surface may include circuitry located on multiple different planes. The multiple planes may include three different planes. The three different planes may include a pair of planes that are

substantially parallel to each other and a third plane that intersects the two substantially parallel planes. The electrical circuitry may further include a plurality of conductive traces, each of which interconnects one of the first set of contact pads with one of the second set of contact pads, each conductive trace having a portion on each of the three different planes. The electrical circuitry may further include a plurality of conductive traces, each of which interconnects one of the first set of contact pads with one of the second set of contact pads.

[0009] The housing may include a recess formed in the bottom surface thereof that receives the image sensor. The camera module may further include a filter positioned within the housing to reduce the amount of infrared light reaching the image sensor. The lens may be received with the housing in a manner that allows the lens to be selectably moved within the housing within a range of positions to position the lens at selectable distances from the image sensor. The image sensor may be connected to the second set of contact pads via solder bumps. The camera module may not include a separate circuit board located between the image sensor and the mobile electronic device. The interface between the camera module and the mobile electronic device may be via a solder connection between the first set of contact pads and contact pads on the mobile electronic device.

[0010] A camera module for attachment to a mobile electronic device includes a housing having a bottom surface on which electrical circuitry is formed thereon, the circuitry including a first set of contact pads for electrical connection to the mobile electronic device and also including a second set of contact pads; a lens received within the housing; and an image sensor electrically and mechanically connected to the housing via the second set of contact pads. The electrical circuitry on the bottom surface includes circuitry Iocated on three different planes, including a pair of planes that are substantially parallel to each other and a third plane that intersects the two substantially parallel planes. The electrical circuitry further includes a plurality of conductive traces, each of which interconnects one of the first set of contact pads with one of the second set of contact pads, each conductive trace having a portion on each of the three different planes. The housing includes a recess formed in the bottom surface thereof that receives the image sensor.

[0011] The camera module further includes a filter positioned within the housing to reduce the amount of infrared light reaching the image sensor. The tens may be received with the housing in a manner that allows the lens to be selectably moved within the housing within a range of positions to position the lens at selectable distances from the image sensor. The image sensor may be connected to the second set of contact pads via solder bumps. The camera module may not include a separate circuit board Iocated between the image sensor and the mobile electronic device. The interface between the camera module and the mobile electronic device may be via a solder connection between the first set of contact pads and contact pads on the mobile electronic device.

[0012] A camera module for attachment to a mobile electronic device includes a housing having a bottom surface on which electrical circuitry is formed thereon, the circuitry including a first set of contact pads that directly interface with and provide direct electrical connection to the mobile electronic device and also including a second set of contact pads; a lens received within the housing; and an image sensor electrically and mechanically connected to the housing via the second set of contact pads. [0013] There may not be a separate circuit board at the interface between the camera module and the mobiie electronic device.

[0014] The interface between the camera module and the mobiie electronic device is via a solder connection between the first set of contact pads and contact pads on the mobile electronic device.

Brief Description of the Drawings

[0015] Figure 1 is an exploded view of a camera module.

[0016] Figure 2 is a lower perspective view of the camera module of Figure 1.

[0017] Figure 3 is an upper perspective view of the camera module of Figure 1.

[0018] Figure 4 is a bottom view of an actuator housing of the camera module of Figure 1.

[0019] Figures 5a, 5b, and 5c are a top view, side view, and bottom view, respectively, of the camera module of Figure 1.

[0020] Figure 6 is a close-up cross-sectional view of the camera module of Figure 1.

Detailed Description

[0021] While the embodiments disclosed herein are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that it is not intended to limit the invention to the particular form disclosed, but rather, the invention is to cover all modifications, equivalents, and alternatives of embodiments of the invention as defined by the claims. The disclosure is described with reference to the drawings, wherein like reference numbers denote substantially similar elements:

[0Q22J FIG. 1 shows a perspective view of a camera module 100 according to one embodiment of the present invention. The camera module 100 includes a lens system 102, an actuator system 104, an infrared (IR) filter 106, and an image sensor 108. As shown, the camera module 100 is exploded along a 2-axis that is optically aligned with the lens system 102 and perpendicularly centered with respect to a planar image sensor surface (not visible) on the top surface of the image sensor 108.

[0023] The Sens system 102 includes an assembly of lenses (not visible) housed therein and is movabiy mounted in the actuator system 104. Accordingly, the lens system 102 and the actuator system 104, together, cooperate as part of an autofocus system of the camera module 100. That is, the lens system 102 is responsive to move along the Z-axis when actuated by the actuator system 104 such that the relative distance between the iens system 102 and the image sensor 108 can be controlled.

[0024] The actuator system 104 includes a top portion 110 and an opposite bottom portion 112. The top portion 110 is adapted to receive the lens system 102. The bottom portion 112 is adapted to receive the IR filter 106 and the image sensor 108. The bottom portion 112 includes three-dimensional (3D) circuitry formed therefore. Further, 3D circuitry 114 is adapted to be electrically connected to image sensor 108 and facilities electrically connecting camera module 100 to the circuitry of a host define (e.g., cell phone). Most electronic circuitry exists in generally planar form. The 3D circuitry 114 herein lies in more than one plane, and thus is called 3D circuitry.

[0025] The IR filter 108 mounts on the actuator system 104, between the bottom portion 112 and the image sensor 108. As shown, the IR filter is aligned with an optical opening formed through the actuator system 104. Not only does the IR filter 108 function as an infrared light filter, but also as a protective shield that prevents debris from accumulating on the image sensor 108. Optionally, an IR filter could be included in the lens system 102 and in such case the IR filter 108 could be replaced by a transparent substrate that functions only as a protective shield.

[0026] The image sensor 108 is adapted to be flip-chip mounted on the bottom portion 112 of the actuator system 104. Although not visible, the image sensor 108 includes a top surface whereon a plurality of electrical contact pads are formed around an image sensor array. The contact pads formed on the image sensor 108 are adapted to be electrically coupled to the 3D circuitry 114 of the actuator system 104.

[0027] FIG. 2 is a top perspective view of the camera module 100 shown assembled. The lens system 102 is movably mounted in an opening formed on the top portion 110 of the actuator system 104.

[0028] FIG. 3 is a bottom perspective view of the camera module 100 shown assembled. The image sensor 108 is flip-chip mounted to the bottom portion 112 and is electrically connected to the 3D circuitry 114.

[002S] FIG. 4 is a bottom view of the actuator system 104 showing some additional details of the bottom portion 112. The 3D circuitry 114 includes a set of flip-chip pads 400 located on a planar surface 408 recessed within the actuator system 104, an associated set of contact pads 402 located on a planar surface 406 peripherally outside of the recess on the bottom portion 112 of the actuator system 104, and an associated set of traces 404 formed therebetween on a wall 410 that connects the two planar surfaces 406 and 408. As can be appreciated, the two planar surfaces 406 and 408 do not lie in the same plane and are vertically-offset from each other. The flip-chip pads 400 are adapted to be electrically connected to the associated set of contact pads formed on the top surface of image sensor 108. The contact pads 402 are adapted to be electrically connected to an associated set of contacts of a host device so as to facilitate the electrically connection of camera module 100 to the host device. Each of the traces 404 electrically connects an associated one of the flip-chip pads 400 to an associated one of the contact pads 402.

[0030] Figures 5a, 5b, and 5c are a fop view, a side view, and a bottom view, respectively, of the camera module 100. As shown in the side view, the camera module 100 does not include a PCB and, therefore, has a lower Z- ejght (height along Z-axis) than conventional camera modules. Indeed, the camera module 100 need not employ a PCB because the 3D circuitry 114 is formed directly on the actuator system 104. The reduced height of the camera module 100 provides more room to optimize lens parameters. Not only is the camera module 100 shorter than conventional camera modules, but also has a lower mechanical stack- up of components and is, therefore, less complex. Due to the lower component stack-up, lower optical tilt can be achieved. For example, optical tilt often results where the glue used to mount the housing on the PCB has an uneven thickness and/or the PCB has poor planarity. In contrast to conventional camera modules, the camera module 100 fits smaller form factors, can be manufactured and designed faster and simpler, can achieve an overall higher image quality, and relaxes host device design constraints.

[0031] FIG. 6 shows a cross-sectional view side view of the camera module 100 taken along section x-x of the engineering drawings of FIG. 5. As shown, bottom portion 112 of actuator system 104 further includes a base/bottom frame 800. In this particular embodiment, the contacts of image sensor 108 are electrically connected to the flip-chip pads 400 of 3D circuitry 114 via flip-chip stud bumps 802 (only one shown). Although stud bumps are discussed, other suitable means for attaching the image sensor to the pads 400 could also be used, such as

conductive epoxy, ACF tape, and so forth. [0032] The disclosed camera module overcomes the problems associated with the prior art by providing a novel design that includes circuitry formed directiy on the actuator. Accordingly, the present invention eliminates the need for a printed circuit board (PCB) located at the point (or interface) where the camera module connects to the mobile electronic device, thus, reducing complexity, time required for design and manufacturing, size, component stack-up, and optica! tilt, and design constraints imparted on host devices. Further, there is no separate circuit board located between the image sensor and the mobile electronic device. The camera module design also improves image quality by providing more space to optimize optical parameters.

[0033J While the embodiments of the invention have been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered as examples and not restrictive in character. For example, certain embodiments described hereinabove may be combinab!e with other described embodiments and/or arranged in other ways (e.g., process elements may be performed in other sequences). Accordingly, it should be understood that only example embodiments and variants thereof have been shown and described.

Claims

WE CLAIfVf :

1. A camera module for attachment to a mobile electronic device, composing:

a housing having a bottom surface on which electrical circuitry is formed thereon, the circuitry including a first set of contact pads for direct electrica! connection to the mobile electronic device and also including a second set of contact pads;

a lens received within the housing; and

an image sensor electrically and mechanically connected to the housing via the second set of contact pads,

2. A camera module as defined in claim 1 , wherein the electrical circuitry on the bottom surface includes three-dimensional circuitry.

3. A camera module as defined in claim 1 , wherein the electrical circuitry on the bottom surface includes circuitry located on multiple different planes.

4. A camera module as defined in claim 3, wherein the multiple planes include three different planes.

5. A camera module as defined in claim 4, wherein the three different planes include a pair of planes that are substantially paraHel to each other and a third plane that intersects the two substantially parallel planes.

6. A camera module as defined in claim 5, wherein the electrical circuitry further includes a plurality of conductive traces, each of which interconnects one of the first set of contact pads with one of the second set of contact pads, each conductive trace having a portion on each of the three different pianes.

7. A camera module as defined in claim 1 , wherein the electrical circuitry further includes a plurality of conductive traces, each of which interconnects one of the first set of contact pads with one of the second set of contact pads.

8. A camera module as defined in claim 1 , wherein the housing includes a recess formed in the bottom surface thereof that receives the image sensor.

9. A camera module as defined in claim 1 , further including a filter positioned within the housing to reduce the amount of infrared light reaching the image sensor,

10. A camera module as defined in claim 1 , wherein the lens is received with the housing in a manner that allows the lens to be selectably moved within the housing within a range of positions to position the lens at selectable distances from the image sensor.

11. A camera module as defined in claim 1 , wherein the image sensor is connected to the second set of contact pads via solder bumps.

12. A camera module as defined in claim 1 , wherein the camera module does not include a separate circuit board located between the image sensor and the mobile electronic device.

13. A camera module as defined in claim 1 , wherein the interface between the camera module and the mobile electronic device is via a solder connection between the first set of contact pads and contact pads on the mobile electronic device.

14. A camera module for attachment to a mobile electronic device, comprising:

a housing having a bottom surface on which electrical circuitry is formed thereon, the circuitry including a first set of contact pads for electrical connection to the mobile electronic device and also including a second set of contact pads; a lens received within the housing; and

an image sensor electrically and mechanically connected to the housing via the second set of contact pads;

wherein the electrical circuitry on the bottom surface includes circuitry located on three different planes, including a pair of planes that are substantially parallel to each other and a third plane that intersects the two substantially parallel planes;

wherein the electrical circuitry further includes a plurality of conductive traces, each of which interconnects one of the first set of contact pads with one of the second set of contact pads, each conductive trace having a portion on each of the three different planes;

wherein the housing includes a recess formed in the bottom surface thereof that receives the image sensor.

15. A camera module as defined in claim 14, further including a filter positioned within the housing to reduce the amount of infrared light reaching the image sensor.

16. A camera module as defined in claim 14, wherein the lens is received with the housing in a manner that allows the lens to be selectably moved within the housing within a range of positions to position the lens at selectable distances from the image sensor.

17. A camera module as defined in claim 14, wherein the image sensor is connected to the second set of contact pads via solder bumps.

18. A camera module as defined in claim 14, wherein the camera module does not include a separate circuit board located between the image sensor and the mobile electronic device.

19. A camera module as defined in claim 14, wherein the interface between the camera module and the mobile electronic device is via a solder connection between the first set of contact pads and contact pads on the mobile electronic device.

20. A camera module for attachment to a mobile electronic device, comprising:

a housing having a bottom surface on which electrical circuitry is formed thereon, the circuitry including a first set of contact pads that directly interface with and provide direct electrical connection to the mobile electronic device and also including a second set of contact pads; a lens received within the housing; and

an image sensor electrically and mechanically connected to the housing via the second set of contact pads.

21 , A camera module as defined in claim 20, wherein there is not a separate circuit board at the interface between the camera module and the mobile electronic device.

22, A camera module as defined in claim 20, wherein the interface between the camera module and the mobile electronic device is via a solder connection between the first set of contact pads and contact pads on the mobile electronic device.