Search

EP-4412230-B1 - CAMERA MODULE ASSEMBLY

EP4412230B1EP 4412230 B1EP4412230 B1EP 4412230B1EP-4412230-B1

Inventors

  • Keng Yew, SONG
  • YUE, ZHANG

Dates

Publication Date
20260513
Application Date
20240122

Claims (18)

  1. Modules for assembling a camera unit (3), the modules comprising: a circuit board (2) comprising: an image sensor (8), and a solder pad (9) located on an upper surface (12) of the circuit board (2), and a lens holder (1) for holding a camera lens (4), comprising a mounting flange (5) with opposed upper and lower surfaces (10, 11), the circuit board (2) and lens holder (1) configured so that when the lens holder (1) and circuit board (2) are assembled together to form the camera module, the lower surface (11) of the lens holder (1) rests adjacent the upper surface (12) of the circuit board (2), and wherein the lens holder (1) comprises a throughbore (6) extending between the upper and lower surfaces (10, 11) of the mounting flange (5), the throughbore (6) positioned to align with the solder pad (9) when the circuit board (2) and lens holder (1) are assembled together, the throughbore (6) configured to receive and retain a solder ball (13) being partially occluded at an occlusion location (15) proximate the lower surface (11), such that the throughbore (6) has a larger open area proximate the upper surface (10) of the mounting flange (5) than at the occlusion location (15).
  2. The modules of claim 1, wherein the throughbore (6) tapers inwardly from the upper surface (10) of the mounting flange towards the occlusion location (15).
  3. The modules of claim 1, wherein the throughbore (6) comprises an internal barrier (17) at the occlusion location (15).
  4. The modules of claim 1, wherein the mounting flange (5) comprises an optical window (7) provided at a side of the throughbore (6) which is at least partially translucent to light energy.
  5. The modules of claim 4, wherein the optical window (7) comprises an aperture.
  6. The modules of claim 4, wherein the optical window (7) comprises an at least partially translucent material, optionally the optical window (7) comprises glass.
  7. The modules of claim 1, comprising a thermal bridge (16) provided proximate the throughbore (6), the thermal bridge (16) comprising a pathway of relatively high thermal conductivity, relative to the mounting flange (5), extending between the throughbore (6) and a surface of the lens holder (1).
  8. The modules of claim 1, wherein the solder pad (9) has a larger area on the upper surface (12) of the circuit board (2) than the area of the throughbore (6) at the lower surface (11) of the mounting flange (5).
  9. A camera unit (3) comprising the modules of claim 1, wherein the lower surface (11) of the mounting flange (5) is affixed to the upper surface (12) of the circuit board (2) with solder (14) extending between the solder pad (9) and the interior of the throughbore (6).
  10. A camera unit (3) comprising: a circuit board (2) comprising: an image sensor (8), and a solder pad (9) located on an upper surface (12) of the circuit board (2), and a lens holder (1) holding a camera lens (4), the lens holder (1) comprising a mounting flange (5) with opposed upper and lower surfaces (10, 11), the circuit board (2) and lens holder (1) being assembled together with the lower surface (11) of the lens holder (1) adjacent the upper surface (12) of the circuit board (2), wherein the mounting flange (5) comprises a throughbore (6) formed therein and extending between the upper and lower surfaces (10, 11) of the mounting flange (5) in alignment with the solder pad (9), the throughbore (6) configured to receive and retain a solder ball (13) being partially occluded at an occlusion location (15) proximate the lower surface (11) of the mounting flange (5), such that the throughbore (6) has a larger open area proximate the upper surface (10) of the mounting flange (5) than at the occlusion location (15), and a solder joint (14) securing the circuit board (2) to the lens holder (1), the solder joint (14) formed on the solder pad (9) and extending into the throughbore (6).
  11. The camera unit (3) of claim 10, wherein the solder (14) extends into the throughbore (6) at least to the occlusion location (15).
  12. The camera unit (3) of claim 10, wherein the mounting flange (5) comprises an optical window (7) provided at a side of the throughbore (6) which is at least partially translucent to light energy.
  13. A method of assembling a camera unit (3), the camera unit (3) comprising: a circuit board (2) comprising an image sensor (8) and a solder pad (9) located on an upper surface (12) of the circuit board (2), and a lens holder (1) holding a camera lens (4), the lens holder (1) comprising a mounting flange (5) with opposed upper and lower surfaces (10, 11) and a throughbore (6) extending between the upper and lower surfaces (10, 11), the method comprising the steps of: i) inserting a solder ball (13) into the throughbore (6) through the upper surface (10) of the mounting flange (5), wherein the throughbore (6) is partially occluded at an occlusion location (15) proximate the lower surface (11) of the mounting flange (5), such that the throughbore (6) has a larger open area proximate the upper surface (10) of the mounting flange (5) than at the occlusion location (15); ii) aligning the lens holder (1) and circuit board (2) within a plane parallel to the upper surface (12) of the circuit board (2); iii) bring the lower surface (11) of the mounting flange (5) and the upper surface (12) of the circuit board (2) together; and iv) melting the solder ball (13) so that solder (14) at least partially flows out of the throughbore (6) and onto the solder pad (9).
  14. The method of claim 13, wherein in step i) the solder ball (13) has a smaller dimension than the throughbore (6) proximate the upper surface (10) of the mounting flange (5), but a larger dimension than the throughbore (6) at the occlusion location (15).
  15. The method of claim 13, wherein step iv) comprises applying laser energy (18) to melt the solder ball (13).
  16. The method of claim 15, wherein step iv) comprises applying laser energy (18) to the solder ball (13) within the throughbore (6) via an optical window (7) at a side of the throughbore (6).
  17. The method of claim 13, wherein step iv) comprises applying thermal energy to the solder ball (13) via a thermal bridge (16) provided proximate the throughbore (6), the thermal bridge (16) comprising a pathway of relatively high thermal conductivity extending between the throughbore (6) and a surface of the lens holder (1).
  18. The method of claim 13, wherein step iii) is performed before step ii).

Description

This invention relates to modules for assembling a camera unit, camera units and a method of assembling a camera unit. Background and Prior Art There is an increasing trend for automotive vehicles to be provided with camera units that obtain images from the exterior of the vehicle. Such camera units may conveniently be adhered to the windshield of a vehicle for example, pointing forward to obtain images from locations in advance of the vehicle. The basic components of such a camera unit are a camera lens, necessary for focusing the image, and an image sensor for receiving the image and outputting image data accordingly. The image data will require processing, which could be performed within the camera unit itself, or alternatively at a remote location, such as the vehicle's control system. To provide a high-quality image, it is essential that the camera lens and the image sensor are accurately aligned. To achieve this, the camera lens is typically held by a first module referred to as a "lens holder", while the image sensor is located on a second module in the form of a circuit board. These two modules may then be aligned before being assembled together. If processing means are provided in the camera unit, these may also be located on the circuit board, or on a separate module, for which accurate alignment is not so important. Typically, an active alignment ("AA") process is used to align the lens holder and circuit board modules, as is well-known in the art per se. When the modules are assembled together, it is important to preserve the alignment, to ensure that the assembly is robust, and also that the ensuing camera unit is as small as possible, to reduce visual obstruction to the vehicle driver's field of vision. A camera unit assembled by aligning and affixing a lens holder module and circuit board module (referred to as an "imager circuit board") is known from US10946812B2 for example. In that system, the lens holder includes a lens holding portion and an attaching portion. The attaching portion includes pins that, when the attaching portion is located at the imager circuit board, are received at least partially through apertures of the imager circuit board. The pins are then soldered at the imager circuit board so as to attach the lens holder to the imager circuit board, with the soldering energy provided by laser. With the pins received at least partially through the apertures, the lens holder is laterally adjusted relative to the imager circuit board to form an aligned imager assembly. The imager assembly is attached at a camera housing, and a processing circuit board is accommodated at the camera housing and electrically connected to the image circuit board. However, this approach has some drawbacks. For example: i) the volume in the aperture is limited by the pins, so there may be insufficient solder material to fill the gap between an imager circuit board and a lens holder. As a result, the well aligned AA result may not be adequately fixed;ii) the gap between an imager circuit board and a lens holder generally is very small, and therefore the soldering energy importing angle is limited; andiii) the pin must well-aligned with the apertures of the image circuit board and then inserted into the latter, which may limit operation space. Examples of specific prior art documents include US 2009/025972 A1 which discloses a camera module structure that is arranged such that a heat-sensitive camera module is joined to a printed wiring board through solder joint sections, and US 6,351,288 B1 which discloses a sensor package assembly for use with an optical assembly. US 2021/029280 A1 further discloses a camera module having a throughhole with a funnel like structure for retaining soldering material used to couple a lower surface of the lens barrel part to an upper surface of a lens holder. The present invention seeks to overcome these problems, and provide a camera unit assembly which improves efficiency and quality of the soldering affixing the lens holder and circuit board modules. In accordance with the present invention this aim is achieved by providing partially occluded throughbores within a mounting part of the lens holder module, which can accommodate a solder ball, and into which soldering energy can be imparted allowing the solder ball to melt and at least partially flow from the bottom of the throughbore and onto a pad of the circuit board. For purposes of clarity and consistency, the following terms as used throughout this text and the appended claims should be interpreted as follows: Solder ball - a discrete mass of solder which may be approximately spherical, but is not so limited and can encompass other discrete masses of solder material, including solder grains; andThroughbore - an aperture extending through a material block which is open at both ends. Summary of the Invention In accordance with a first aspect of the present invention there are provided modules for assembling a camera unit