Method for producing a camera module, camera module

Abstract

The invention relates to a method for producing a camera module (12), in which a housing (11), in which an image sensor is accommodated, and a lens (10) are joined and glued together, wherein the lens (10) is aligned with the image sensor during the joining process and wherein, for the purpose of gluing, an adhesive (3) is introduced into an adhesive gap (1) which is delimited by adhesive surfaces (2) formed on the housing (11) and on the lens (10). According to the invention, at least one of the adhesive surfaces (2) is provided with a positive profile (4) which is spaced from at least one edge (6) of the adhesive surface (2), and which locally reduces the adhesive gap (1). During the joining and alignment process, excess adhesive (3) is displaced from an area of ​​smaller gap height to an area of ​​larger gap height. The invention further relates to a camera module (12) comprising a housing (11) in which an image sensor is accommodated, and a lens (10) which are adhesively bonded to one another, wherein an adhesive (3) is introduced into an adhesive gap (1) which is delimited by adhesive surfaces (2) formed on the housing (11) and on the lens (10). According to the invention, at least one of the adhesive surfaces (2) has a positive profile (4) spaced from at least one edge (6) of the adhesive surface (2).

Description

[0001] The present invention relates to a method for producing a camera module according to the preamble of claim 1. Furthermore, the invention relates to a camera module. State of the art

[0002] To support safety, comfort, and autonomous systems, camera modules are often installed in vehicles. These have a modular design and usually comprise a housing and a lens, along with other components. The housing usually contains a circuit board to which an image sensor is attached. The image sensor and circuit board are rigidly connected to the housing. The lens is inserted into the housing and usually secured using an adhesive bond. To form the adhesive bond, both the lens and the housing have adhesive surfaces that define an adhesive gap into which the adhesive is applied. Since the interior of the housing must also be airtight and watertight, the adhesive surfaces are usually designed to extend all the way around.

[0003] Camera modules typically do not have active focusing. To achieve a sharp image, the lens's image plane must be aligned with the camera's image sensor during production. This usually occurs after the adhesive bond is applied but before the adhesive cures. This alignment process is also known as active alignment.

[0004] The precision with which Active Alignment must be performed means that all mechanical tolerances in the tolerance chain between the lens and image sensor must be compensated for in this step. Two options are available for performing Active Alignment. One is varying the height of the adhesive gap, and the other is tilting the lens and housing against each other. Since a large number of individual tolerances affect the final position of the lens relative to the housing, the compensation for these tolerances performed during Active Alignment leads to a large variance in the adhesive gap height, which in individual cases is not known in advance during design and application of the adhesive. If the adhesive gap height has to be reduced during Active Alignment, the volume of adhesive applied during the manufacturing process often no longer fits completely into the adhesive gap. The result is the formation of overhangs.These are undesirable for cosmetic reasons and also represent a waste of material.

[0005] Conversely, to avoid overhangs, the adhesive surfaces are often widened during design. This provides more volume for the intended adhesive and overhangs can be avoided. However, this approach significantly limits the ability to use tilting during active alignment. Furthermore, it is accompanied by a restriction on the mechanical dimensions of the camera, which restricts the lens diameter and / or the housing width. The wider the adhesive surfaces and thus the adhesive gap, the more sensitive the adhesive gap height at the outer edges of the adhesive bond is to tilting. To ensure a reliable and tight adhesive bond, however, a minimum adhesive gap height must be maintained across the entire adhesive bond. The wider the adhesive surfaces, the smaller the available tilt angle resulting from this boundary condition.

[0006] The present invention is concerned with the task of ensuring a reliable and tight adhesive bond with the smallest possible adhesive surface width. To achieve this task, the method with the features of claim 1 is proposed. Advantageous further developments of the invention are set forth in the subclaims. Furthermore, a camera module is specified. Disclosure of the invention

[0007] A method for producing a camera module is proposed, in which a housing, in which an image sensor is accommodated, and a lens are joined and glued together, wherein the lens is aligned with the image sensor during the joining process, and wherein, for the purpose of bonding, an adhesive is introduced into an adhesive gap defined by adhesive surfaces formed on the housing and on the lens. According to the invention, at least one of the adhesive surfaces is provided with a positive profile spaced from at least one edge of the adhesive surface, which profile locally reduces the adhesive gap, and during the joining and alignment process, excess adhesive is displaced from an area of ​​smaller gap height to an area of ​​larger gap height.

[0008] Adding a positive profile to an adhesive surface, spaced from at least one edge of the adhesive surface, results in the adhesive gap no longer having a uniform height. Specifically, the height of the adhesive gap is greater in at least one edge area than further in. The resulting clearance provides an escape route for adhesive displaced during the joining or alignment process. This prevents overhangs.

[0009] Without the positive profile of at least one bonding surface, the escape volume for the adhesive would have to be provided differently to avoid overhangs, which is typically achieved by widening the bonding surfaces during design. The invention thus also enables a reduction in dimensions and opens up the possibility of further downscaling of components and saving installation space.

[0010] Spacing the positive profile from both edges of at least one adhesive surface is advantageous because the adhesive gap is always at its smallest between the profile and the opposite adhesive surface. When adhesive is applied to the profile, it can spread to both sides. Spacing the profile from both edges of the adhesive surface creates space on both sides of the profile for the adhesive to spread.

[0011] It is further proposed that the adhesive gap be designed as an axial gap. A radial gap would not maintain a uniform adhesive gap height in the event of radial displacement of the lens relative to the housing. On the contrary, such a displacement would risk both a local undershoot of the minimum adhesive gap height required for a reliable adhesive bond and a local overshoot of the maximum permissible adhesive gap height elsewhere. This disadvantage does not arise when aligning the lens to the image sensor using an axial gap for the adhesive bond. With this preferred embodiment, alignment by means of both radial and axial displacement is therefore possible without any problems.

[0012] Furthermore, it is proposed that the adhesive be applied primarily, preferably only, to the positive profile of the at least one adhesive surface. The advantage of this preferred embodiment is lower adhesive consumption compared to applying the adhesive in the edge regions. In the case of a maximum gap height, the adhesive bond can be achieved solely by the adhesive located between the profile and the opposing side. Significantly more adhesive would be required if the adhesive gap height had to be bridged via one of the free spaces instead of the adhesive gap height between the profile and the opposite adhesive surface.

[0013] It is further proposed that the alignment be carried out by varying the gap height and / or tilting the lens and the housing relative to each other. Varying the gap height is subject to the constraints of a minimum bonding gap height and a maximum bonding gap height, but is generally feasible. Particularly with the preferred design of the bonding gap as an axial gap, the bonding gap height changes evenly over the entire circumference. Reaching the limit values ​​is therefore easy to determine and rectify. Due to the free space created by the profile, the bonding gap height is increased by the amount of the profile height. Tilting the lens relative to the housing entails the risk of falling below the required minimum bonding gap height in the areas remote from the tilt axis.Due to the increase in adhesive gap height in the area of ​​the free space, the maximum permissible tilt angle is increased, so that more scope is available for alignment without jeopardizing the reliability of the adhesive bond.

[0014] Furthermore, a camera module is proposed, comprising a housing in which an image sensor is accommodated, and a lens, which are bonded together, wherein an adhesive is introduced into an adhesive gap defined by adhesive surfaces formed on the housing and the lens. According to the invention, at least one of the adhesive surfaces has a positive profile spaced from at least one edge of the adhesive surface.

[0015] In a further development of the invention, it is proposed that the positive profile of the at least one adhesive surface has a cross-sectional shape that protrudes into the adhesive gap and is at least partially angular, in particular triangular, square, or trapezoidal, and / or rounded. In the case of a trapezoidal shape, the cross-sectional shape can, in particular, be uniformly trapezoidal or ramp-shaped. Different cross-sectional geometries for individual sections are conceivable. Different cross-sectional geometries can offer different advantages.

[0016] It is further proposed that the positive profile of the at least one adhesive surface forms at least one plateau, which is preferably bordered on one or both sides by a slope. The slope creates a continuously expanding free space for accommodating excess adhesive, so that the adhesive displaced into the free space is more likely to maintain contact with both adhesive surfaces.

[0017] It is further proposed that the housing and / or the lens be made of aluminum, at least in the area of ​​the respective adhesive surface. Aluminum has special adhesive properties that create a special surface tension in the adhesive, further reducing the risk of protrusions despite the clearance created by the profile.

[0018] An exemplary embodiment of the invention is described in more detail below with reference to the figures. The figures illustrate the following content: Fig. 1 a cross-section through a first camera module according to the invention in the area of ​​an adhesive gap at maximum adhesive gap height, Fig. 2 a cross-section through the camera module of the Fig. 1 with minimum adhesive gap height, Fig. 3 a cross-section through a camera module not according to the invention in the region of an adhesive gap, Fig. 4 a cross-section through a second camera module according to the invention in the region of an adhesive gap, Fig. 5 a cross section through a third camera module according to the invention in the region of an adhesive gap and Fig. 6 a schematic representation of the sequence of a method according to the invention. Character description

[0019] Fig. 1 shows a cross section through a camera module 12 according to the invention in the region of an adhesive gap 1, which connects a lens 10 and a housing 11 of the camera module 12. The adhesive gap 1 is delimited on both sides by adhesive surfaces 2, between which adhesive 3 is applied. One of the adhesive surfaces 2 is provided with a positive profile 4 spaced from at least one edge 6 of the adhesive surface 2. In the Fig. In the preferred embodiment depicted in Figure 1, the profile 4 has a rectangular cross-section. Other cross-sectional geometries are possible. The adhesive 3 is preferably applied to the profile 4. Due to the spacing from at least one edge 6 of the adhesive surface 2, there is a free space 5 between the profile 4 and the edge 6 of the adhesive surface 2, into which space excess adhesive 3 can escape when the adhesive gap 1 is reduced. The height of the adhesive gap 1 is maximum in the configuration depicted. It allows the lens 10 to be tilted relative to the housing 11 in order to align the lens 10 with respect to an image sensor housed in the housing 11.

[0020] Fig. 2 shows a cross section of the camera module 12 of the Fig. 1 in the area of ​​the adhesive gap 1 after minimizing the adhesive gap 1, whereby n minimum distance was maintained between the profile 4 and the opposite adhesive surface 2. Since the adhesive gap height is greater towards the edge 6, excess adhesive 3 was displaced into this area.

[0021] Fig. 3 shows a cross-section through a camera module 13 not according to the invention in the region of an adhesive gap 1 between a lens 10 and a housing 11. The adhesive gap 1 is delimited on both sides by adhesive surfaces 2, between which adhesive 3 is applied. In this case, none of the adhesive surfaces 2 is profiled. Excess adhesive 3, which is displaced from the adhesive gap 1 when the adhesive gap height is reduced, thus forms a projection 7.

[0022] Fig. 4 shows a cross section through a second camera module 12 according to the invention in the region of an adhesive gap 1. The lower adhesive surface 2 has a positive profile 4 which forms a plateau 8 which is delimited towards the edge 6 by a bevel 9.

[0023] Fig. 5 shows a cross section through a third camera module 12 according to the invention in the region of an adhesive gap 1. The lower adhesive surface 2 has a positive profile 4 which forms a plateau 8 which is delimited towards both edges 6 by a bevel 9.

[0024] Fig. 6 shows a schematic representation of the method steps of a method according to the invention. The subject of this method is the production of a camera module 12 with a lens 10 and a housing 11, wherein an image sensor is accommodated in the housing 11. In a first method step S1, an adhesive surface 2 on the lens 10, or alternatively on the housing 11, designated to receive a subsequently inserted adhesive connection is provided with a positive profile 4 spaced from an edge 6 of the adhesive surface 2. The structural dimensioning of this profile 4 is based on the design of the adhesive connection to be inserted in a later method step and the adhesive volume estimated within the scope of the design.

[0025] Process step S1 preferably takes place during the manufacture of the lens 10 or the housing 11. In a subsequent process step S2, adhesive 3 is applied to one of the adhesive surfaces 2, preferably the profiled one and in this case preferably to the profile 4. The thickness of the adhesive bead is designed in advance based on design factors. In a subsequent process step S3, the housing 11 and the lens 10 are joined such that the adhesive surfaces 2 form an adhesive gap 1. In a subsequent process step S4, which takes place before the adhesive bond cures, the lens 10 is aligned with the image plane of the image sensor. Alignment is achieved by varying the height of the adhesive gap 1 and by tilting the lens 10 and the housing 11 relative to one another.The height of the adhesive gap 1 is limited by a maximum height, which in the illustrated embodiment corresponds to the sum of the profile height and the adhesive bead thickness, and a minimum height that must be met to ensure the reliability of the bond and which must not be exceeded locally. A configuration having the maximum adhesive gap height is shown in . Fig. 1. When the height of the adhesive gap 1 is reduced, excess adhesive 3 is pressed into a free space 5, which extends from the profile 4 to the edge 6 of the adhesive surface 2 (analogous Fig. 2). This ensures that the distance between the profile 4 and the opposite adhesive surface 2 maintains the minimum adhesive gap height. By displacing adhesive 3 into the free space 5, the formation of a projection 7, typical for bonding of housing 11 and lens 10 carried out in methods not according to the invention, as exemplified in Fig. 3 shown, avoided.

[0026] When tilting the lens 10, it must also be ensured that the maximum and minimum adhesive gap heights are maintained, especially in the edge areas remote from the tilt axis. After alignment, the adhesive bond cures in a final process step S5.

Claims

[1] Method for producing a camera module (12), in which a housing (11), in which an image sensor is accommodated, and a lens (10) are joined and glued together, wherein the lens (10) is aligned with the image sensor during the joining process and wherein, for the purpose of gluing, an adhesive (3) is introduced into an adhesive gap (1) which is delimited by adhesive surfaces (2) formed on the housing (11) and on the lens (10), characterized by that at least one of the adhesive surfaces (2) is provided with a positive profile (4) spaced from at least one edge (6) of the adhesive surface (2), which profile locally reduces the adhesive gap (1), and during joining and alignment, excess adhesive (3) is displaced from an area of ​​smaller gap height to an area of ​​larger gap height. [2] Method according to claim 1, characterized by that the adhesive gap (1) is designed as an axial gap. [3] Method according to one of the preceding claims, characterized bythat the adhesive (3) is applied primarily, preferably only, to the positive profile (4) of the at least one adhesive surface (2). [4] Method according to one of the preceding claims, characterized by that the alignment is carried out by varying the gap height and / or tilting the lens (10) and the housing (11) against each other. [5] Camera module (12) comprising a housing (11) in which an image sensor is accommodated, and a lens (10) which are glued together, wherein an adhesive (3) is introduced into an adhesive gap (1) which is delimited by adhesive surfaces (2) formed on the housing (11) and on the lens (10), characterized by that at least one of the adhesive surfaces (2) has a positive profile (4) spaced from at least one edge (6) of the adhesive surface (2). [6] Camera module (12) according to claim 5, characterized bythat the positive profile (4) of the at least one adhesive surface (2) has a cross-sectional shape which projects into the adhesive gap (1) and is at least partially angular, in particular triangular, quadrangular, or trapezoidal, and / or rounded. [7] Camera module (12) according to one of claims 5 or 6, characterized by that the positive profile (4) of the at least one adhesive surface (2) forms at least one plateau (8) which is preferably delimited on one or both sides by a slope (9). [8] Camera module (12) according to one of claims 5 to 7, characterized by that the housing (11) and / or the lens (10) is / are made of aluminum at least in the area of ​​the respective adhesive surface (2).

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