Method for producing a sensor assembly

Abstract

The invention relates to a method for producing a sensor assembly (1) comprising at least one printed circuit board (2), an element (3) sensitive to electromagnetic radiation, a sensor head and a housing (4), comprising the following steps: - providing (S1) a printed circuit board panel consisting of a plurality of printed circuit boards (2) for a payload separating process carried out by a separating tool, an element (3) sensitive to electromagnetic radiation being mounted on each printed circuit board (2) of the printed circuit board panel; - providing (S2) a camera system for determining an active surface (3a) of the element (3) sensitive to electromagnetic radiation of the respective printed circuit board (2); - determining (S3) the active surface (3a) and defining a reference point on the active surface (3a); - aligning (S4) the separating tool with the reference point; - separating (S5) a printed circuit board (2) from the printed circuit board panel using the separating tool, the separating tool producing a stop on the printed circuit board (2); - pressing (S6) the printed circuit board (2) in the housing against the stop; - mounting (S7) the sensor head in the housing (4), the centre axis of the sensor head being aligned with the active surface (3a) of the element (3) sensitive to electromagnetic radiation.

Description

[0001] Method for manufacturing a sensor assembly

[0002] The invention relates to a method for producing a sensor assembly comprising at least a circuit board, an image sensor, a lens arrangement and a housing.

[0003] In the state-of-the-art sensor manufacturing processes, the components and tools used are individually aligned to each other in each process step. The resulting tolerance chain can have a negative impact on the entire manufacturing process. Typically, according to the state of the art, for example, an optical system is actively aligned to the imager or imager package.

[0004] It is therefore an object of the present invention to provide a method for producing a sensor assembly, by means of which a precise alignment of the individual components and a reduction of the tolerances is made possible.

[0005] This object is solved by the subject matter of independent claim 1. Further advantageous embodiments are the subject matter of the subclaims.

[0006] Initial considerations were that two of the main factors influencing the tolerance chain are the soldering process of the imager package and the tolerances of the imager package itself. Due to these process requirements, it is difficult to improve the accuracy of the image sensor placement on the circuit board, as well as the reference surfaces. Placing an image sensor more precisely on a circuit board or improving the image sensor package tolerances using currently available methods would result in higher costs.

[0007] According to the invention, a method for producing a sensor assembly comprising at least one circuit board, an image sensor, a lens arrangement and a housing is therefore proposed, comprising the following steps:

[0008] - Providing a printed circuit board panel consisting of a plurality of printed circuit boards for a panel separation process by means of a separation tool, wherein an image sensor is mounted on each printed circuit board of the printed circuit board panel;

[0009] - Providing a camera system for determining an active area of ​​the respective image sensor of the respective circuit board; - Determining the active area and setting a reference point on the active area

[0010] - Aligning the cutting tool to the reference point;

[0011] - Separating a printed circuit board from the printed circuit board panel using the separating tool, whereby the separating tool creates a stop on the printed circuit board;

[0012] - Pressing the circuit board in the housing against the stop;

[0013] - Mounting the lens assembly in the housing, wherein an optical axis of the lens assembly is aligned with the active area of ​​the image sensor.

[0014] The printed circuit board panel is manufactured using a known process. An element sensitive to electromagnetic radiation is attached to each printed circuit board. The panel separation process is carried out using a known separation method and a separation tool. The element sensitive to electromagnetic radiation is preferably an image sensor. The sensor head is preferably a lens or lens arrangement, and the sensor assembly is accordingly a camera. However, it would also be conceivable to produce other types of sensors, such as a lidar sensor, using the process presented here.

[0015] By determining the active area using the provided camera system, the size and orientation of the element sensitive to electromagnetic radiation can be determined and a reference point can be set accordingly. The separation tool is aligned to this reference point and the corresponding circuit board is then separated from the panel. Setting a reference point based on the determined active area is advantageous because it allows potential deviations in the alignment of the element to be taken into account and the circuit board can be separated from the panel accordingly. The stop created in this way enables more precise alignment of the circuit board in the housing and also more precise alignment of a sensor head that is attached later. In contrast, with a previously defined reference point, which is independent of the orientation of the image sensor orof the active surface, deviations can already occur between the stop generated during separation and the alignment of the element, and subsequent installation in the housing as well as the alignment of a sensor head to the element can, in turn, lead to further deviations. In a preferred embodiment, the separation is performed using a laser. The use of a laser as a separation tool is particularly advantageous with regard to the precision of a laser.

[0016] In another preferred embodiment, pressing the circuit board into the housing enables 3-axis alignment of the circuit board. The alignment in the x- and y-directions is directly determined by the generated precise stop. Pressing the circuit board against the stop into the housing also automatically enables roll angle adjustment.

[0017] Particularly preferably, the reference point on the active surface is defined at a center point of the active surface. Defining the reference point at a center point of the active surface is advantageous because, due to the symmetry of the element sensitive to electromagnetic radiation or the symmetry of the circuit board, all distances from the center point to the respective opposite side surfaces of the element and the respective opposite side surfaces of the circuit board should be approximately equal. Accordingly, if the separating tool is aligned to the reference point at the center of the active surface, the circuit board can be separated from the circuit board panel in such a way that the respective opposite edges of the circuit boards have almost the same distance from the reference point. This makes it possible, for example, to compensate for a deviation when placing the element on the circuit board.

[0018] Furthermore, the central axis of the sensor head is preferably aligned to the reference point on the active surface.

[0019] Further advantageous embodiments are shown in the drawings, which show:

[0020] Fig. 1 : a schematic flow diagram of a method according to an embodiment of the invention;

[0021] Fig. 2: a schematic representation of a sensor assembly;

[0022] Fig. 3: another schematic representation of a sensor assembly. Figure 1 shows a schematic flow diagram of a method according to one embodiment of the invention. In the method for producing a sensor assembly comprising at least one printed circuit board 1, an element 2 sensitive to electromagnetic radiation, a sensor head and a housing 4, in step S1 a printed circuit board panel consisting of a plurality of printed circuit boards 1 is provided for a panel separation process, wherein the panel separation process is carried out by means of a separation tool, wherein an element 2 sensitive to electromagnetic radiation is attached to each printed circuit board 1 of the printed circuit board panel. In a step S2, a camera system is provided for determining an active area 3a of the element 3 sensitive to electromagnetic radiation of the respective printed circuit board 2.In a further step S3, the active area 3a is determined and a reference point on the active area is set. In a step S4, the separating tool is aligned to the reference point. In step S5, a printed circuit board 2 is separated from the printed circuit board panel using the separating tool, whereby a stop is created on the printed circuit board 2 by the separating tool. Subsequently, in step S6, the printed circuit board 2 separated from the panel in this way is pressed into a provided housing 4 against the stop A3, B3 of the printed circuit board. In a further step S7, the sensor head is mounted in the housing 4, whereby the central axis of the sensor head is aligned with the active area 3a of the element 3 sensitive to electromagnetic radiation.

[0023] Figure 2 shows a schematic representation of a sensor assembly. The sensor assembly 1 comprises a printed circuit board 2, an element 3 sensitive to electromagnetic radiation with an active surface 3a, and a housing. The reference symbols A1 and B1 each describe the outer surfaces of the housing. The reference symbol B2 describes a horizontal axis of symmetry of the printed circuit board 2 and the reference symbol A2 a vertical axis of symmetry of the printed circuit board 2. These two axes of symmetry A2, B2 intersect at a point M, which is also the center of the printed circuit board 2 and the element 3 sensitive to electromagnetic radiation. The intersection point M can be used, for example, as a reference point for aligning the cutting tool and for later alignment of a sensor head. The reference symbols A4 and B4 each describe an inner surface of the housing 4, against which the printed circuit board 2 is pressed with the surfaces A3 and B3.A stop was created on the outer surfaces A3, B3 of the printed circuit board 2 by the separating tool when it was removed from the panel. This stop enables precise alignment of the printed circuit board 2 in the housing 4. Figure 3 shows a further schematic representation of a sensor assembly. In this representation, the housing 4 with a printed circuit board 2 is shown from a side opposite the element 3 sensitive to electromagnetic radiation. It is also shown that the outer surfaces A3, B3 of the printed circuit board 2 are pressed against the inner surfaces A4 and B4 of the housing 4 in the x-direction Rx and y-direction Ry. This pressing results in alignment in the x- and y-directions as well as a roll angle adjustment.

[0024] List of reference symbols

[0025] 1 sensor assembly

[0026] 2 Circuit board 3 Element sensitive to electromagnetic radiation

[0027] 3a active area of ​​the element

[0028] 4 housings

[0029] A1 , B1 Outer surface housing

[0030] A2, B2 symmetry axes A3, B3 outer surfaces of the circuit board

[0031] A4, B4 interior surfaces housing

Claims

Patent claims 1 . A method for producing a sensor assembly (1) comprising at least one circuit board (2), an element (3) sensitive to electromagnetic radiation, a sensor head and a housing (4), comprising the following steps: - Providing (S1) a printed circuit board panel consisting of a plurality of printed circuit boards (2) for a panel separation process by means of a separation tool, wherein an element (3) sensitive to electromagnetic radiation is attached to each printed circuit board (2) of the printed circuit board panel; - Providing (S2) a camera system for determining an active area (3a) of the element (3) sensitive to electromagnetic radiation of the respective circuit board (2); - determining (S3) the active surface (3a) and defining a reference point on the active surface (3a); - Alignment (S4) of the cutting tool to the reference point; - separating (S5) a printed circuit board (2) from the printed circuit board panel by means of the separating tool, wherein a stop is created on the printed circuit board (2) by the separating tool; - pressing (S6) the circuit board (2) in the housing against the stop; - Mounting (S7) the sensor head in the housing (4), wherein the central axis of the sensor head is aligned with the active surface (3a) of the element (3) sensitive to electromagnetic radiation.

2. Method according to claim 1, characterized in that the separation is carried out by means of a laser.

3. Method according to claim 1, characterized in that when the circuit board (2) is pressed into the housing (4), a 3-axis alignment of the circuit board (2) is made possible.

4. Method according to claim 1, characterized in that the reference point on the active surface is defined at a center point (M) of the active surface (3a).

5. Method according to claim 1, characterized in that the central axis of the sensor head is aligned with the reference point on the active surface (3a).

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