Method for producing a camera system, and camera system

Abstract

The invention relates to a method for producing a camera system (10) comprising a housing (2), an image sensor (3) accommodated in the housing (2), and an objective (1) to be aligned with respect to the image sensor (3), wherein the objective (1) is inserted at least in part into the housing (2) and is fixed in the housing (2). According to the invention, after fixing the objective (1) in the housing (2), the position of the objective (1) in relation to the image sensor (3) is specifically altered by applying a weld seam (4) to a housing region (6) accommodating the objective (1). The invention also relates to a camera system (10).

Description

[0001] R.416659

[0002] - 1 -

[0003] Description

[0004] Title:

[0005] Method for manufacturing a camera system, camera system

[0006] The present invention relates to a method for manufacturing a camera system having the features of the preamble of claim 1. The invention further relates to a camera system.

[0007] State of the art

[0008] Camera systems, such as those used in driver assistance systems, typically comprise a housing containing an image sensor and a lens inserted into this housing. To obtain a sharp image, the lens must be correctly positioned relative to the image sensor. The accuracy requirements for this positioning are typically in the micrometer range. To fix the lens in the housing during this assembly step, both material-bonded connections (e.g., adhesive bonds) and form-fit (stapling) or force-fit (clamping, screwing) connections can be used. The main disadvantage of these methods is that once the lens position is fixed during the assembly step, it cannot be further adjusted, and residual manufacturing tolerances must be accepted. These tolerances, such as...Adhesive shrinkage, relaxation during curing processes, and stress input or reduction from subsequent processes are on the order of a few micrometers and cannot be accurately predicted or controlled in individual cases. This results in highly inhomogeneous camera systems with respect to focal lengths and depth of field at the end of the manufacturing process, consequently exhibiting significant differences in image sharpness. Subsequent repositioning of the lens relative to the image sensor is generally not possible.

[0009] Several solutions already exist to overcome this problem. These solutions generally aim for greater control over the final positioning during assembly. For example, publication DE102010047106A1 discloses a camera system in which the lens and housing are connected via an R.416659

[0010] - 2 -

[0011] The integrated adjustment element is connected to each other. Alternatively, German patent DE102021212985A1 proposes ensuring more precise positioning during the joining process using optical measurement. German patent US20110298968A1, in turn, discloses a six-axis lens mounting system with which the joining process can be carried out with higher precision. However, all these proposed solutions address the problem during the joining process and are therefore unable to correct the subsequent changes and settling effects caused by the residual tolerances described above. Thus, it remains the case that once a lens has been joined to its housing and the bond has cured, a subsequent correction of the lens's alignment relative to the image sensor is no longer possible.

[0012] The invention therefore addresses the problem of changing the orientation of a lens of a camera system relative to its image sensor even after joining and curing or solidification of the connection. To solve this problem, a method with the features of claim 1 is proposed. Further preferred embodiments are described in the dependent claims. A camera system is also proposed.

[0013] Disclosure of the invention

[0014] A method for manufacturing a camera system comprising a housing, an image sensor housed in the housing, and a lens that can be aligned with respect to the image sensor is proposed, wherein the lens is inserted at least partially into the housing and fixed within the housing. According to the invention, after fixing the lens in the housing, the position of the lens with respect to the image sensor is selectively changed by applying a weld seam to a housing area that receives the lens. The transverse shrinkage of the weld seam occurring during the welding process causes displacements of the housing parts separated by it relative to each other, which are in the range of a few micrometers. These lead to displacements and / or tilting of the lens relative to the image sensor. The fixing is preferably an adhesive bond, can be R.416659

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[0016] but it can also be a form-fit or force-fit connection such as a screw connection or crimp connection.

[0017] In a further development of the invention, it is proposed that the weld be performed as a blind weld. This eliminates the need for the housing to consist of two parts joined by the weld. By using a blind weld, the housing can be manufactured from a single piece, simplifying the manufacturing process and reducing the number of necessary work steps.

[0018] Furthermore, it is proposed that the housing surrounds an end section of the lens and that the weld be applied circumferentially. With a fully circumferential weld, the lens is shifted along the image axis relative to the image sensor by the lateral shrinkage of the weld, without any tilting. In this way, axial positional deviations can be corrected in the absence of tilting.

[0019] It is also proposed that a tube-shaped section of the housing be used as the housing area. Such a section typically has a smaller radius than the rest of the housing. The transverse shrinkage is on the order of a few micrometers. A smaller radius of the housing area accommodating the weld seam means that the transverse shrinkage can result in a greater tilt of the lens relative to the image sensor than with a larger radius.

[0020] It is further proposed that a material-bonded connection, preferably an adhesive bond, be used to fix the lens in the housing. Material-bonded connections are stable after curing and are generally not affected by subsequent modifications to the housing. For example, with a screw connection or a clamping connection, it would have to be ensured that the transverse shrinkage of the weld seam does not lead to loosening of the connection in the micrometer range.

[0021] Furthermore, it is proposed that, in order to selectively change the position of the lens in relation to the image sensor, the weld thickness and / or the R.416659

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[0023] The welding temperature is varied along the length of the weld. By varying the weld thickness and / or welding temperature, a circumferential weld, which primarily causes a displacement of the lens relative to the image sensor, can simultaneously achieve a tilting effect. Thus, a circumferential weld can simultaneously implement both displacement and tilting.

[0024] It is further proposed that a micro-welding process, preferably a laser welding process, be used to apply the weld. With a micro-welding process, the weld can be even smaller, and more precise control over the dimensions of the weld itself, and consequently its transverse shrinkage, can be exercised than with a conventional welding process.

[0025] Furthermore, a camera system is proposed which is manufactured according to a method according to the invention. Such a camera system has the aforementioned properties and advantages.

[0026] The invention is explained in more detail below with reference to figures. These show:

[0027] Figure 1 shows a schematic representation of a camera system in sectional view, (A) before and (B) after application of a method according to the invention and

[0028] Figure 2 shows an exemplary illustration of two camera systems according to the invention.

[0029] Character description

[0030] Fig. 1A shows a section through a camera system 10. The lens 1 is fixed in a housing 2 in a single assembly step. For this purpose, the housing 2 has a tube-shaped housing section 6 that at least partially surrounds the lens 1. An image sensor 3 is arranged in the housing 2. The focal image plane 5, sometimes also called the focusing plate in technical jargon, is located due to a R.416659

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[0032] Due to inaccurate positioning during assembly or subsequent curing or settling processes, the lens 1 is not in the plane of the image sensor 3, but is shifted by the amount dz and tilted by the amount Rx. In Fig. 1B, a weld seam 4, preferably a blind weld seam, is applied to the same camera system 10 from part A, circumferencing the housing area 6 on the outside. The transverse shrinkage of the weld seam 4 selectively changes the position of the lens 1 relative to the image sensor 3. The focal image plane 5 of the lens 1 is therefore also shifted and tilted, which in this example leads to an approximation of the focal image plane 5 to the image sensor plane.

[0033] Fig. 2 shows two exemplary camera systems 10 according to the invention. These comprise a lens 1 which is fixed in a housing 2. A weld seam 4 runs around a housing area 6 of the housing 2 which at least partially surrounds the lens 1. After the fixation has hardened, a change in the position of the lens 1 relative to an image sensor (not shown in Fig. 2) arranged in the housing 2 is effected by means of this weld seam.

Claims

R.416659 - 6 - Claims 1. Method for manufacturing a camera system (10) comprising a housing (2), an image sensor (3) received in the housing (2) and a lens (1) to be aligned with respect to the image sensor (3), wherein the lens (1) is inserted at least partially into the housing (2) and fixed in the housing (2), characterized in that after fixing the lens (1) in the housing (2) the position of the lens (1) with respect to the image sensor (3) is selectively changed by applying a weld seam (4) to a housing area (6) receiving the lens (1).

2. Method according to claim 1, characterized in that the weld (4) is performed as a blind weld.

3. Method according to claim 1 or 2, characterized in that the housing area (6) surrounds an end section of the lens (1) and the weld seam (4) is applied circumferentially.

4. Method according to one of the preceding claims, characterized in that a housing area (6) designed as a tube is used as the housing area (6) of the housing (2).

5. Method according to one of the preceding claims, characterized in that a material-bonded connection, preferably an adhesive connection, is used to fix the lens (1) in the housing (2).

6. Method according to one of the preceding claims, characterized in that the weld thickness and / or the weld temperature is varied over the length of the weld (4) in order to selectively change the position of the lens (1) in relation to the image sensor (2).

7. A method according to any of the preceding claims, characterized in that a micro-welding process, preferably a laser welding process, is used to apply the weld seam (4). R.416659 - 7 - 8. Camera system (10) manufactured according to a method of claims 1 to 7.

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