WO2007124994A1

WO2007124994A1 - Optical module, and method for the production of an optical module

Info

Publication number: WO2007124994A1
Application number: PCT/EP2007/053065
Authority: WO
Inventors: Oliver Menke; Christian Meyer; Harald Schmidt; Andreas Winterl
Original assignee: Continental Automotive Gmbh
Priority date: 2006-04-27
Filing date: 2007-03-30
Publication date: 2007-11-08
Also published as: DE102006019717A1

Abstract

The invention relates to an optical module (1, 14, 23) comprising a lens device (3) for projecting electromagnetic radiation (13), an image sensor (7) with a sensitive area, a sensor support (6) with an opening (6a) and a support area (6c) on which the image sensor (7) is mounted in the zone of the opening, and a sensor support holder (5, 10, 15, 17, 30) for mounting the sensor support (6) such that the support area (6c) faces away from the lens device (3) and the lens device (3) projects the electromagnetic radiation (13) onto the sensitive area of the image sensor (7). The sensor support holder (5, 10, 15, 17, 30) is embodied in such a way that the support area (6c) of the sensor support (6), which faces away from the lens device (3), is disposed at a predefined distance from the lens device (3). The invention further relates to a method for producing such an optical module (1, 14, 23).

Description

description

Optical module and method for manufacturing an optical module

The invention relates to an optical module and a method for producing an optical module

DE 102 26 135 A1 discloses an optical module which has a lens device for projecting electromagnetic radiation, an image sensor and a sensor carrier with an opening and a support surface on which the image sensor is attached by flip-chip technology in the region of the opening , having. The sensor carrier is attached to the optical module such that the carrier surface is remote from the lens device and the lens device projects the electromagnetic radiation onto the sensitive surface of the image sensor. In order to achieve a sufficient image sharpness with the optical module, the components of the optical module must be geometrically relatively precisely matched to each other. The tolerance range for the distance from the image sensor to the lens device in the direction of that axis which is aligned at right angles to the sensitive area of the image sensor should be kept as accurately as possible and preferably be within a range ≦ 0.5 mm. In particular, if the sensor carrier has a not significant thickness tolerance or if different sensor carriers are used for the optical module, then it may be necessary to adjust the optical module, for example, with a thread on the housing of the optical module. Such an adjustment is relatively expensive, especially in mass production of optical modules.

The object of the present invention is therefore to design an optical module such that sensor carriers of different thickness can be used without readjusting the lens device for the optical module. The task It is also an object of the invention to provide a corresponding method for producing such an optical module.

The invention is achieved by an optical module, comprising a lens device for projecting electromagnetic radiation, an image sensor with a sensitive surface, a sensor carrier with an opening and a support surface, on which the image sensor in particular by means of flip-chip technology in the Opening is fixed, and a sensor holder holder for mounting the sensor carrier such that the support surface facing away from the lens device and the lens device projects the electromagnetic radiation on the sensitive surface of the image sensor, characterized in that the sensor holder holder is designed such that the lens device facing away from Carrier surface of the sensor carrier is aligned relative to the lens device in a fixed predetermined distance. The electromagnetic radiation is, in particular, visible light which impinges on the sensitive surface of the image sensor, so that the image sensor converts it into electrical signals in a generally known manner, whereby an image data record assigned to an image is produced. The image sensor is for example a CMOS or CCD image sensor and is in particular in flip-chip technology on the sensor carrier, which is for example a printed circuit board attached. The image sensor is fastened in the region of the opening of the sensor carrier on the support surface facing away from the lens device, and the lens device projects the electromagnetic radiation into the region of the opening so that the electromagnetic radiation falls on the sensitive surface. The optical module further comprises the sensor holder holder with which the sensor carrier is mounted. This is designed such that the lens device facing away Tragerflache the sensor carrier regardless of its thickness always has the fixed predetermined distance. The image sensor is preferably attached to the sensor carrier by flip-chip technology, whereby high tolerances due to the attachment, for example by solders, remain within relatively narrow tolerances. Thus, the sensitive surface is substantially in the plane determined by the carrier surface of the sensor carrier facing away from the lens device, ie the sensitive surface of the image sensor, has the predetermined distance to the lens device, regardless of the thickness of the sensor carrier used.

In order to achieve a sufficient depth of field of the optical module, the focusing of the lens device should be aligned as possible on the sensitive surface of the image sensor. Since, however, the distance between the lens device and the support surface facing away from the lens device of the sensor carrier is always the same regardless of the thickness of the sensor carrier, the lens device can be pre-set to this distance without an adjustment is necessary during the assembly of the optical module. As a result, the optical module can be produced relatively quickly and therefore cost-effectively.

According to a variant of the optical module, this comprises a housing in which the lens device is mounted, and the sensor holder holder is part of the housing. Thus, it is possible to produce the housing with integrated sensor holder, for example by injection molding, relatively simple, but also relatively accurate tolerance.

According to one embodiment of the optical module whose sensor support holder is designed such that the assembly of the optical module facing away from the lens device carrier surface of the sensor carrier self-aligning reference lent to the lens device in the fixed predetermined distance aligns. In particular, according to a variant, the optical module of the sensor holder is designed such that aligns the opening of the sensor sensor self-aligning in a predetermined position relative to the lens device when assembling the optical module, the optical module is not only relatively simple and fast and therefore cost but there are also advantages statements for a relatively consistently high quality of the optical module given.

The sensor carrier holder of the module comprises z. B. holding means on which the lens device facing away from the support surface of the sensor carrier and which ensure that the distance between the lens device remote from the carrier surface of the sensor carrier and the lens device does not exceed the fixed predetermined distance. In particular, if according to a variant of the optical module whose sensor carrier holder comprises at least one compression spring which presses the sensor carrier against the holding means, it can be achieved with relatively simple means that the lens surface facing away from the carrier device self-adjusting occupies the fixed predetermined distance.

The compression spring is, for example, collar-shaped and / or annular and / or is made of an elastomeric material. Such a compression spring not only presses the sensor holder against the holding means, but can additionally protect the image sensor or the lens device against environmental influences, such as dust or moisture.

According to one embodiment of the optical module, the holding means also prevent a displacement of the circuit carrier in the plane defined by the sensor carrier. Thus, the image sensor not only has the predetermined distance to the lens device, but the lens device always projects the electromagnetic radiation to the sensitive surface of the image sensor.

According to embodiments of the optical module, the holding means have at least one snap-action hook in which the sensor carrier snaps, a screw, a pin and / or a bolt and / or the sensor carrier holder has a partial surface which forms a common surface with the carrier surface of the sensor carrier facing away from the lens device forms a flat surface and the holding means are fixed to the part surface. The object of the invention is also achieved by a method for producing an optical module, comprising the following method steps: attaching a lens device for projecting electromagnetic radiation in a housing such that the lens device focuses the electromagnetic radiation to a predetermined location at a predetermined distance from the lens device and attaching a sensor carrier having an opening and a support surface to which an image sensor in the region of the opening is preferably secured by flip-chip technology such that the support surface facing away from the lens device and the lens device facing away from the support surface the predetermined distance to the lens device Has.

According to a variant of the method, the sensor carrier is attached to the housing by applying the sensor carrier to the housing such that the carrier surface is remote from the lens device. Subsequently, a stop member is applied to the housing and the sensor wearer such that the stop member against the image sensor and / or the lens device facing away from carrier surface prints such that the lens device facing away Tragerflache has the predetermined distance to the lens device. Finally, the sensor carrier is attached to the housing with an adhesive. By the stop member is ensured that the lens device facing away from Tragerflache regardless of the thickness of the sensor carrier has the fixed predetermined distance to the lens device.

If the abutment part according to a variant is also designed such that it holds the opening in a predetermined position relative to the lens device, then the opening of the sensor carrier and thus the sensitive surface of the image sensor is always at a predetermined position relative to the lens device, so that the Focusing the lens device does not need to be readjusted. According to a further embodiment of the method, the sensor carrier is fastened to the housing on a sensor carrier holder of the housing. The sensor carrier holder preferably comprises holding means, which align the sensor carrier self-aligning with respect to the lens device in the fixed predetermined distance.

With such an optical module or method it is possible to achieve a relatively accurate positioning of the image sensor or its sensitive surface in the case of a positioning in the Z direction, ie. Focusing on the lens device to obtain. Further advantages are a permanent focus and a relatively reliable adjustment of the optical module. By the holding means and a relatively accurate positioning of the image sensor in the lens device facing away from the carrier surface is possible.

Embodiments of the invention are illustrated by way of example in the schematic accompanying drawings. Show it:

FIG. 1 is a sectional view of a first embodiment of an optical module;

FIG. 2 shows the optical module of FIG. 1 in an exploded view;

FIG. 3 is a sectional view of a second embodiment of an optical module;

FIG. 4 shows the optical module shown in FIG. 3 in an exploded view;

Figure 5 shows a third embodiment of an optical module in a sectional view and

6 shows the optical module of Figure 5 in an exploded view. FIG. 1 shows an optical module 1 in a sectional representation and FIG. 2 shows the optical module 1 in an exploded view. The optical module 1 comprises a housing 2, in which optical lenses 3 are firmly anchored during assembly of the optical module 1, so that no further optical adjustment is possible. Furthermore, the lenses 3 are focused during assembly to a point at a fixed predetermined distance from the lenses 3.

The housing 2 comprises in the case of the present exemplary embodiment, three snap hooks 5, of which only two snap hooks 5 are visible in Figures 1 and 2. The snap hooks 5 are intended to receive a printed circuit board 6 with a thickness d and an opening 6a.

The printed circuit board 6 has a first board surface 6c and a second board surface 6c. On the second board surface 6b of the circuit board 6, an image sensor 7 with a photosensitive surface in flip-chip technology is soldered in the region of the opening 6a such that the photosensitive surface is accessible through the opening 6a. By the flip-chip technique, it is possible that the photosensitive surface of the image sensor 7 and the second support surface 6c of the printed circuit board 6 are substantially in the same plane.

In the mounted state, the second board surface 6b faces away from the lenses 3, so that a light bundle 13 passing through the lenses 3 and focused by the lenses 3 is directed onto the opening 6a of the printed circuit board 6 and thus strikes the photosensitive surface of the image sensor 7 , In a generally known manner, the sensor 7 converts this light into corresponding electrical signals which are further processed by electronic components 12 located on the printed circuit board 6, whereby an image data record is generated whose associated image is displayed, for example, with a screen, not shown in the figures can be. Before the printed circuit board 6 is snapped into the snap hooks 5, an annular spring element 10 made of an elastomer, in the case of the present exemplary embodiment of silicone rubber, is placed in an annular groove 9 of the housing 2. The annular spring element 10 is so thick that, when the printed circuit board 6 is snapped into the snap hooks 5, it is printed together and thus the printed circuit board 6 against bearing surfaces 4 of the snap hooks 5 prints. This ensures that the lenses 3 remote from the second support surface 6c of the printed circuit board 6 regardless of the thickness d in a fixed by the bearing surfaces 4 of the snap hook 5 level relative to the lenses 3 runs. In the case of the present exemplary embodiment, the annular spring element 10 not only prints the printed circuit board 6 against the bearing surfaces 4 of the snap hooks 5, but also seals the printed circuit board 6 and the housing 2, for example against moisture, dust or other environmental influences.

In the case of the present exemplary embodiment, the housing 2 of the optical module 1 further comprises two centering pins 11, which engage in corresponding bores 8 of the printed circuit board 6 in the attached state of the printed circuit board 6. By the centering pins 11, the printed circuit board 6 is automatically adjusted when attaching the circuit board 6 to the housing 2 such that the opening 6a a predetermined position relative to the plane defined by the lenses 3 second support surface 6c plane is aligned relative to the lenses 3. In addition, since the image sensor 7 is angelotet at a fixed predetermined location on the lenses 3 remote from the second support surface 6c of the printed circuit board 6, and the sensitive surface of the image sensor 7 has set in the plane facing away from the lenses 3 second support surface 6c certain level Position.

By the snap hook 5 thus results in a relatively simple mounting of the optical module 1, since during assembly, only the circuit board 6 with the already angelote- th image sensor 7 needs to be snapped. In addition, it is ensured in combination with the spring element 10 that the lens carrier 3 facing away from the second support surface 6c regardless of the thickness d of the printed circuit board 6 used in a fixed predetermined distance to the lenses 3 is aligned, which is already known and prior to assembly the support surfaces 4 of the snap hook is determined. This distance is also the distance with which the lenses 3 are focused during assembly.

FIG. 3 shows a sectional view of a further optical module 14 and FIG. 4 shows the optical module 14 in an exploded view. Unless otherwise described below, components of the optical module 14 shown in FIGS. 3 and 4, which are substantially identical in construction and function to components of the optical module 1 shown in FIGS. 1 and 2, are given the same reference numerals.

The optical module 14 shown in FIGS. 3 and 4 differs substantially from the optical module 1 shown in FIGS. 1 and 2 in that the printed circuit board 6 only has two snap hooks 5, of which only one of the snap hooks in FIGS 5 is shown, in addition to a screw 15 is attached to the housing 2. For the attachment of the screw 15, the housing 2 comprises a threaded bore 16 into which the screw 15 is screwed during assembly of the optical module 14. The bore 16 is in the case of the present exemplary embodiment in a socket 17 of the housing 2. The nozzle 17 in turn comprises at its end facing away from the housing 2 a taper 21 with a support surface 18, to which the screw contact surface 19 of the screw head 20 of Screw 15 in the assembled state of the optical see module 14 firmly. Furthermore, the printed circuit board 6 has a further opening 22, in which the taper 21 of the nozzle 17 is inserted when the optical module 14 is assembled. The support surface 18 of the nozzle 17 is der- aligned art that it lies in the same plane, which is defined by the support surfaces 4 of the two snap hooks 5.

When assembling the optical module 14, in turn, first the spring element 10 is placed in the groove 9 of the housing 2. Subsequently, the printed circuit board 6 is pushed with the image sensor 7 laterally into the snap hooks 5 and inserted with its further opening 22 in the taper 21 of the nozzle 17. Thereafter, the screw 15 is tightened. As a result, the opening 6a and thus the photosensitive surface of the image sensor 7 are in a fixed predetermined position relative to the lenses 3.

FIG. 5 shows a further optical module 23 in a sectional illustration and FIG. 6 shows the optical module 23 in an exploded view. Unless otherwise described below, components of the optical module 23 shown in FIGS. 5 and 6, which are substantially identical in construction and function to components of the optical module 1 shown in FIGS. 1 and 2, are given the same reference numerals.

The optical module 23, in turn, comprises a housing 2, in which lenses 3 fixedly mounted fixedly at a fixed distance. For the assembly of the optical module 23, however, the printed circuit board 6 provided with the image sensor 7 is first held with a stop member 24 against abutment surfaces 25 of the housing 2. In order to achieve this, the stopper part 24 has position cams 26 which can be pushed through corresponding openings 27 in the printed circuit board 6.

The stop member 24 also includes stop cams 28, which rest on the rear side of the optical sensor 7 and thereby limit the maximum distance of the lens 3 remote from the carrier surface 6c of the printed circuit board 6. If the printed circuit board 6 or the image sensor 7 prints against the stop cam 28 of the stop member 24, then a gap arises between the printed circuit board 6 and a lower boundary surface 29 of the housing 2. The gap is filled with an adhesive 30. After the adhesive 30 has cured, the circuit board 6 is fixed to the housing 2, so that the abutment member 24 can be removed. During the curing of the adhesive 30, the stop member 24 prints the image sensor 7 against the housing 2, so that the lens 3 remote from the carrier surface 6c of the board 6 is aligned after curing of the adhesive 30 at a fixed predetermined distance from the lenses 3. In the case of the present exemplary embodiment, the adhesive 30 also protects the image sensor 7 from dust, moisture or other environmental influences.

By the position cam 26 and the corresponding openings 27 of the printed circuit board 6, this is also aligned automatically so that the opening 6a for the image sensor 7 are again in a fixed position predetermined relative to the lenses 3.

LIST OF REFERENCE NUMBERS

1 optical module

2 housings

3 lenses

4 support surfaces

5 snap hooks

6 printed circuit board

6a opening

6b first carrier surface

6c second support surface

7 image sensor

8 holes

9 groove

10 spring element

11 stop cam

12 electronic components

13 bundles of light

14 optical module

15 screw

16 hole

17 nozzles

18 bearing surface

19 screw contact surface

20 screw head

21 rejuvenation

22 opening

23 optical module

24 stop part

25 bearing surfaces

26 position cams

27 openings

28 stop cam

29 lower boundary surface

30 Adhesive d Thickness

Claims

claims

1. An optical module comprising a lens device (3) for projecting electromagnetic radiation (13), an image sensor (7) having a sensitive surface, a sensor carrier (6) having an opening (6a) and a support surface (6c), on which the image sensor (7) is fixed in the region of the opening (6a), and - a sensor carrier holder (5, 10, 15, 17, 30) for fastening the sensor carrier (6) such that the carrier surface (6c) of the lens device (3) and the lens device (3) projecting the electromagnetic radiation (13) onto the sensitive surface of the image sensor (7), characterized in that the sensor holder holder (5, 10, 15, 17, 29) is designed in this way in that the carrier surface (6c) of the sensor carrier (6) facing away from the lens device (3) is aligned at a fixed predetermined distance relative to the lens device (3).

2. An optical module according to claim 1, comprising a housing (2) in which the lens device (3) is fastened, and the sensor holder holder is part of the housing (2).

3. An optical module according to claim 1 or 2, the sensor carrier holder (5, 10, 15, 17) is designed such that when assembling the optical module (1, 14) of the lens device (3) facing away Tragerflache (6 c) the sensor carrier (6) self-aligning posted relative to the lens device (3) in the fixed predetermined distance.

4. Optical module according to one of claims 1 to 3, the sensor carrier holder (5, 10, 15, 17) is designed such that when assembling the optical module (1, 14), the opening (6 a) of the sensor carrier (6) self-adjusting in a Aligns predetermined position relative to the lens device (3).

5. Optical module according to one of claims 1 to 4, the sensor carrier holder holding means (5, 15, 17), on which the lens device (3) facing away from support surface (6c) of the sensor carrier (6) and ensure that the Distance between the lens device (3) facing away from the carrier surface (6b) of the sensor carrier (6) and the lens device (3) does not exceed the fixed predetermined distance.

6. An optical module according to claim 5, wherein the holding means (5, 15, 17) prevent a displacement of the sensor carrier (6) in the plane defined by the sensor carrier (6).

7. An optical module according to claim 5 or 6, the holding means comprise at least one snap hook (5) in which the sensor carrier (6) snaps.

8. Optical module according to one of claims 5 to 7, the sensor carrier holder (5, 10, 15, 17) comprises a partial surface (18) facing away from the lens device (3) support surface (6c) of the sensor carrier (6) common flat surface forms and the holding means (15) are fixed to the partial surface (18).

9. An optical module according to claim 8, wherein the holding means comprise a screw (15), a pin and / or a bolt.

10. Optical module according to one of claims 5 to 9, the sensor carrier holder (5, 15, 17) comprises at least one compression spring (10) which presses the sensor carrier (6) against the holding means (5, 15, 17).

11. An optical module according to claim 10, wherein the compression spring (10) is collar-shaped and / or annular and / or is made of an elastomeric material.

12. An optical module according to any one of claims 2 to 11, the sensor carrier (6) is glued to the housing (2).

13. A method for producing an optical module (1, 14, 23), comprising the following method steps:

Mounting a lens device (3) for projecting electromagnetic radiation (13) into a housing (2) such that the lens device (3) focuses the electromagnetic radiation (13) to a predetermined location at a predetermined distance from the lens device (3) - siert, and

Fixing a sensor carrier (6) having an opening (6a) and a support surface (6c), to which an image sensor (7) in the region of the opening (6a) is fastened such that the

Carrier surface (6c) facing away from the lens device (3) and the lens device (3) facing away Tragerflache (6c) has the predetermined distance to the lens device (3).

14. The method of claim 13, wherein the image sensor (7) on the sensor carrier (6) is attached by flip-chip technology.

A method according to claim 13 or 14, wherein the step of attaching the sensor carrier (6) to the housing (2) is performed as follows:

Applying the sensor carrier (6) to the housing (2) such that the carrier surface (6c) is remote from the lens device (3), - applying a stop member (24) to the housing (2) and the sensor carrier (6) in that the abutment part (24) prints against the image sensor (7) and / or the carrier surface (6b) facing away from the lens device (3) such that the carrier surface (6b) facing away from the lens device (3) has the predetermined distance from the lens device (3) , and

Attaching the sensor carrier (6) with an adhesive (30) on the housing (2).

16. The method of claim 15, wherein the stop member (24) is adapted to hold the opening (6a) in a predetermined position relative to the lens device (3).

A method according to claim 13 or 14, wherein the step of attaching the sensor carrier (6) to the housing (2) is performed as follows: attaching the sensor carrier (6) to a sensor carrier holder (5, 10, 15, 17) of the housing ( 2).

18. The method of claim 17, wherein the sensor holder holder comprises holding means (5, 15, 17) which align the sensor carrier (6) self-aligned with respect to the lens device (3) in the fixed predetermined distance.