DE102009027514A1 - Camera module and method for its production - Google Patents

Abstract

The invention relates to a camera module (1), in particular for a vehicle, the camera module (1) comprising at least: a carrier device (2), an image sensor (3) which is received directly or indirectly on the carrier device (2), a lens holder (5), which is attached to the carrier device (2), and a lens (10) with at least one lens (11), which is received in the lens holder (5) and by means of an adhesive (12) sensitive to UV radiation (16) ) is fixed. According to the invention, UV-transparent areas (14) are formed on the lens holder (5) and at least part of the adhesive (12) is provided in the area of the UV-transparent areas (14).

Description

State of the art

The The invention relates to a camera module or imager module, in particular can be used in a vehicle, as well as a method for its Production.

such Camera modules with fixed focus or fixed focal length and object width especially in vehicles and in the automotive sector Detection of an external space around the vehicle or else one Vehicle interior used. Here is one as a semiconductor device trained image sensor on its circuit carrier or sensor carrier z. B. a circuit board, mounted together with other components, so that subsequently a lens holder on the circuit carrier can be set, which seals the image sensor to the outside and to take the lens. The lens is from the top inserted into the lens holder, positioned and fixed.

Around a permanent mechanical assurance of the distance between the Lens and the image sensor to achieve, the lens in general screwed by a thread in the lens holder and in the appropriate Fixed axial position. In addition to mechanical connections such. B. threadlockers Welding or bonding techniques are also used.

The US 2006/0119730 A1 shows a camera module in which a lens with a lens is screwed from above into a lens holder. Here, the lens is screwed in from above until it reaches the front of a spacer, which is placed on a shoulder of the lens holder. Thus, the focus or the image size is already determined by this geometric design, without a subsequent correction of the focus is possible.

at Threadlockers can punctiform forces act on the lens, thereby the optical performance can be affected. For laser welding is on the one hand a relatively high cost for the plant engineering and safety is required, there is also a risk that the punctual heat stress mechanical stresses in the system enters, which can cause a delay.

disadvantageous At adhesive joints is generally that curing The adhesive takes longer and depending on the adhesive design by a temperature step is to bring. By the handling of the parts between the last optical inspection in the focusing device and also by pressure changes In the heating phase, it can lead to an uncontrollable defocusing come.

in this connection Some of the camera modules require very high optical demands also a subsequent change Focusing is no longer possible. Thus, the Structure very sensitive to a change in position of the lens relative to the image sensor. Already a shift in the order of magnitude of a few 10 μm, the image sharpness can deteriorate, that the camera module does not work for high quality applications can be used.

The DE 103 42 529 A1 shows a camera assembly, which is particularly suitable for use in a motor vehicle, wherein on the underside of the lens and the top of a lens mount grooves and webs are formed such that concentric guideways are formed. The lens in this case has a conical shape with a hemispherical underside, ie in the form of a spherical cap. The fixing takes place via an adhesive connection, which is formed in a downwardly tapering gap between the lens receptacle formed as part of a housing and the upwardly conically tapering objective. In this case, a UV-sensitive adhesive can be used, which can be irradiated from above through the gap.

The CN 1704786 A shows a corresponding camera module, in which a lens is screwed from above into a lens holder. The assembly is performed by first screwing the lens until a suitable position is reached, then introducing the UV-curing adhesive into a plurality of holes of the peripheral wall of the lens holder and curing with UV radiation through the holes. Subsequently, a thermosetting plastic between a circumferential groove of the lens and the upper edge of the lens holder is introduced for final fixation.

The formation of holes in the lens holder allows this while the supply of adhesive and also the UV irradiation for curing; Such holes or recesses in the wall of the lens holder are manufacturing technology but not unproblematic, since burrs or residues can remain in the production, which break in the subsequent assembly, ie screwing the lens from the top, and thus reach the optical path can. The particles introduced in this way increase the risk of deterioration of the optical properties and of losses in yield, since the particles can significantly impair the image quality due to shading or scattered light. Furthermore, such a two-step bond is relatively expensive. The first bond by the UV-curing adhesive he initially follows only in marginal areas of the holes between the threads of the lens and the lens holder and therefore acts only in small areas, so that subsequently takes place the additional bonding by the thermosetting adhesive in the groove provided for this purpose.

Disclosure of the invention

According to the invention a fixation of the lens in the lens holder by a UV-sensitive adhesive or adhesive, d. H. an adhesive during or after UV irradiation at least partially reacted. According to the invention the UV irradiation through a UV-transparent region of the lens holder, d. H. through the material of the lens holder.

in this connection becomes "UV-transparent" according to the invention Area of the lens holder understood, the at least one sufficient large proportion of UV radiation passes through that a reaction of the UV-sensitive adhesive begins, with a certain Proportion of the supplied UV radiation can be absorbed.

According to one inventive design can be a UV-activatable Glue or adhesive can be used after activation by the UV radiation below at corresponding thermal Conditions, e.g. B. room temperature or supplementary Supply of heat, reacted.

Of the Adhesive is preferably between the outside of the Lens and the cylindrical inner surface of a holder area of the lens holder introduced as an adhesive film, which without connection to an outside space, d. H. not over a window or a groove is connected to the outside space.

The UV-transparent areas can be particularly thin-walled be educated. According to the invention is hereby recognized that some such thin-walled areas in Circumferentially distributed on the holder portion of the lens holder sufficient to irradiate the glue, leaving the other thick-walled Ensure adequate stability. Thus, the formation of thin-walled areas for the stability is unproblematic.

The thin-walled areas can thus z. B. as local limited pockets are formed, between which thick-walled Areas are formed. In particular, these thin-walled Areas on the top of the lens holder or its cylindrical Holder area be formed so that between and below These thin-walled areas with a thick-walled training with high strength can be provided. In such a training In particular, there is the possibility of a cost-effective Production of the lens holder as an injection molded part, wherein the lens holder as a substantially cup-shaped or cup-shaped Component with wider mounting area for mounting on the circuit board and one more still adjoining, essentially cylindrical holder area with at its top distributed arranged pockets may be formed.

According to the invention some advantages. So the lens holder in a closed Sleeve wall, d. H. without openings, holes or Breakthroughs are trained and yet a sufficient large-area bonding done. It turns out thus, in particular, not the problems mentioned in the introduction the formation of holes in the sleeve wall can occur by the particular during assembly Particles can get into the optical path. According to the invention a closed, dense education can be achieved, in which the Incorporation of interfering particles and contamination avoided is and still a large-scale bonding can be done. Furthermore, a low-cost training of Lens holder as a component in injection molding of plastic possible. Despite the partially thin-walled Training is still a high according to the invention Stability achieved.

By the use of a UV-activatable adhesive can in this case first the high strength of the adhesive bond to the directly cured thin-walled areas, and a subsequent improvement the adhesive bond by reacting the other areas be reached, to which the UV energy initially insufficient could be introduced.

Another advantage is that according to the invention instead of a conventional thread formation between the lens and lens holder and purely axial displacements are possible, for. B. also with smooth cylindrical surfaces. This z. B. a linear adjustment or a linear drive for axial adjustment and positioning can be used. Thus, an additional degree of freedom in the azimuth angle, ie. in the relative rotation of the lens in the plane perpendicular to the optical axis allows, if necessary, to improve the image quality. According to the invention, an in situ positioning and fixation is possible. Since the UV-curing adhesive reacts quickly in the directly irradiated areas, thus positioning by z. B. a linear drive, z. B. even when the image sensor or image sensor under evaluation of its image signals and upon reaching the appropriate positioning by the UV irradiation curing, the following directly be checked in situ in order to allow final acceptance and, if necessary, rejection as a committee.

The thin-walled areas according to the invention in this case allow a higher power transmission than the z. B. in the CN 1704786 A provided UV adhesive bond in edge areas of holes. In principle, the thin-walled regions can already form a sufficient surface for the formation of high forces, wherein optionally a subsequent curing by UV activation can also take place in the further, thicker-walled regions.

The Location and shape of the UV-permeable areas can According to the invention are designed to be variable to the integration of one or more UV light sources in the focusing distance to allow and absorb the UV light sources in to enable a manufacturing process.

Brief description of the drawings

1 shows the structure of a camera module according to the invention in a partially sectioned representation;

2 shows the camera holder in perspective view;

3 shows a flow chart of the manufacturing method according to the invention.

Description of the embodiments

In 1 is a camera module according to the invention 1 shown in a partially sectioned illustration. On a serving as a carrier device or circuit board circuit board 2 are an image sensor 3 and other components 4 mounted and contacted. The image sensor 3 can be designed in particular as a semiconductor device. As another component 4 can another integrated circuit, for. B. serving as a control device microprocessor 4 , be provided. On the top 2a the circuit board 2 is still a lens holder 5 mounted in the 2 shown in more detail. The lens holder 5 has a lower, widened attachment area 5a and an upwardly adjoining cylindrical holder portion 5b on. The attachment area 5a is in 1 shown cut to the arrangement of the image sensor 3 within this light-tight mounting area 5a to show. At the attachment area 5a are screw receptacles (fastening straps) 6 with holes 7 formed with corresponding holes 8th in the circuit board 2 Align so that screws 9 are passed through it for attachment.

In the holding area 5b is a lens 10 set in the at least one lens not shown here in more detail 11 is included. The setting of the image width b, ie the distance between the lens 11 or - with multiple lenses 11 - The optical reference plane of the plurality of lenses to the sensitive surface of the image sensor 3 along the optical axis A takes place by longitudinal adjustment of the lens 10 in the holder area 5b of the lens holder 5 ,

According to the invention, the position of the lens 10 in the holder area 5b through an adhesive layer 12 Made of UV-curing adhesive. The adhesive layer 12 is here completely between the cylindrical outer surface 10a of the lens 10 and the cylindrical inner surface 5c of the holder area 5b educated.

According to the invention for this purpose in the holder area 5b thin-walled areas, in particular thin-walled pockets 14 arranged distributed in the circumferential direction. How out 2 a second wall thickness d2 of the holder area can be seen 5b in the field of bags 14 smaller than a first wall thickness d1 in the other areas. The bags 14 are circumferentially on the holder area 5b distributed; they can z. B. be arranged at a height. This can be any bag 14 through a recess from the outside 5d of the holder area 5b be formed ago, so that the inner surface 5c of the holder area 5b represents a smooth cylindrical surface into which the cylindrical lens 10 can be used appropriately. In 2 is the adhesive layer 12 on the inner surface 5c in the area of a bag 14 located. The second thickness d2 of the pockets 14 is z. B. in the range of less than 0.2 mm, z. B. from 0.1 to 0.15 mm. The first thickness d1 of the holder area 5b can be significantly higher, z. B. at 0.5 to 1.0 mm. As the holder area 5b not continuous thin-walled, but in the circumferential direction between the pockets 14 and below the pockets 14 thick-walled areas are provided, we the stability of the lens holder 5 through the pockets 14 not impaired.

in this connection can z. B. high quality plastics such as LCP or PPS used which react very viscous in the melt and thus also allow such small wall thicknesses to be produced reliably. Here, different reinforcing materials or reinforcing portions in the plastic for further optimization be used.

Advantageously, the inner surface 5c and the cylindrical outer surface 10a thread-free, in particular cylindrically smooth. Basically, however, is the formation of an internal thread on the inner surface 5c and according to a male thread on the outer surface 10a mög Lich.

In the illustrated design, the entire lens holder 5 be made as an injection molded part of a suitable plastic material, since it represents a substantially pot-shaped component. Also the training of the bags 14 at the upper end or upper edge of the holder area 5b is possible directly by injection molding by the pockets 14 to the top edge 5e of the holder area 5b pass.

The production of the camera module according to the invention from the three modules, ie with the image sensor 3 and optionally other components 4 equipped printed circuit board 2 , furthermore the lens holder 5 and as the third assembly of the lens 10 takes place according to the flowchart of 3 in that, after the start in step St0, the lens holder is subsequently in step St1 5 on the circuit board 2 is mounted, for. B. over the holes 7 . 8th and screws 9 such that the optical axis A, the center through the image sensor 3 runs concentrically and centrally through the holder area 5b runs. In step St2, the objective becomes the lens 10 inserted from above and positioned along the optical axis A. Here, the image sensor 3 be turned on, so that its image signals can be evaluated to verify the appropriate focus. When reaching the desired height or position of the lens 10 Next, in step St3, UV light becomes 16 in the radial direction on the thin-walled pockets 14 irradiated, so that part of the UV radiation 16 through the thin-walled pockets 14 up to the adhesive layer 12 and thus the UV adhesive layer 12 directly cured, or, with UV-activated adhesive 12 by the irradiation with the UV radiation 16 the reaction of the glue 12 is started, which subsequently subsequently reacted by a dual mode of action of heat or possibly even room temperature over a longer time. In principle, the adhesive layer 12 also completely in the circumferential direction on the inner surface 5c are introduced and in the UV irradiation initially only in the area of the pockets 14 cure to ensure first secure positioning and subsequently in the other areas between the pockets 14 cure.

The longitudinal adjustment of the lens 10 in the holder area 5b can in the preferred thread-free training z. B. done by a linear drive in the balancing system. Here, if appropriate, a suitable azimuth orientation, ie angular position of the lens 10 in the lens holder 5 to get voted.

After the UV irradiation and at least partial curing, the correct focusing can subsequently be performed directly in step St4 by the operation of the image sensor 3 be checked.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 2006/0119730 A1 [0004]
• DE 10342529 A1 [0008]
• - CN 1704786A [0009, 0020]

Claims (14)

Camera module ( 1 ), in particular for a vehicle, wherein the camera module ( 1 ) at least comprises: a carrier device ( 2 ), an image sensor ( 3 ) placed on the support ( 2 ) is received directly or indirectly, a lens holder ( 5 ) placed on the support ( 2 ) and a lens ( 10 ) with at least one lens ( 11 ), which in the lens holder ( 5 ) and by means of a UV radiation ( 16 ) sensitive adhesive ( 12 ) is fixed, characterized in that on the lens holder ( 5 ) at least one UV-transparent region ( 14 ) is formed, and at least a part of the adhesive ( 12 ) in the region of the at least one UV-transparent region ( 14 ) is provided. Camera module according to claim 1, characterized in that the UV-sensitive adhesive ( 12 ) by UV radiation ( 16 ) is designed to be activated for subsequent curing. Camera module according to claim 1 or 2, characterized in that the lens holder ( 5 ) a fastening area ( 5a ) for attachment to the support device ( 2 ) and a substantially cylindrical holder area ( 5b ) for receiving the lens ( 10 ) and the at least one UV-transparent region ( 14 ) as a thin-walled region ( 14 ) in the holder area ( 5b ) are formed. Camera module according to claim 3, characterized in that the UV radiation ( 16 ) sensitive adhesives ( 12 ) as an adhesive layer ( 12 ) between an outer surface ( 10a ) of the lens ( 10 ) and an inner surface ( 5c ) of the lens holder ( 5 ) is trained. Camera module according to claim 3 or 4, characterized in that a plurality of thin-walled regions ( 14 ) distributed in the circumferential direction on the holder area ( 5b ) are formed and the holder area ( 5b ) between the thin-walled regions ( 14 ) is formed with a first wall thickness (d1) that is greater than a second wall thickness (d2) of the thin-walled regions (d1). 14 ). Camera module according to one of claims 3 to 5, characterized in that the at least one thin-walled areas than from a top edge ( 5e ) of the holder area ( 5b ) downwardly extending pocket ( 14 ) is trained. Camera module according to one of the preceding claims, characterized in that the lens holder ( 5 ) Is designed as an injection molded part made of plastic. Camera module according to one of the preceding claims, characterized in that an inner surface ( 5c ) of the holder area ( 5b ) and an outer surface ( 10a ) of the lens ( 10 ) thread-free, preferably smooth, are formed. Camera module according to one of the preceding claims, characterized in that the carrier device ( 2 ) a circuit carrier, for. B. a circuit board ( 2 ), the lens holder ( 5 ) on the upper side of the circuit carrier ( 2 ), z. B. is screwed and the image sensor ( 3 ) light-tight within the lens holder ( 5 ) is arranged. Method for producing a camera module ( 1 ), with at least the following steps: Attaching a lens holder ( 5 ) on a support device ( 2 ) on which an image sensor ( 3 ), wherein the lens holder ( 5 ) at least one UV-transparent region ( 14 ), inserting a lens ( 10 ) in the lens holder ( 5 ) and positioning the lens ( 10 ) by axial displacement along an optical axis (A) of the lens holder ( 5 ) and the image sensor ( 3 ), wherein on an outer surface ( 10a ) of the lens ( 10 ) and / or an inner surface ( 5c ) of the lens holder ( 5 ) a UV-sensitive adhesive ( 12 ) and fixing the position of the lens ( 10 ) by irradiating at least a portion of the adhesive ( 12 ) from the outside through the at least one UV-transparent region ( 14 ) of the lens holder ( 5 ). A method according to claim 10, characterized in that during the positioning of the lens in the lens holder an evaluation of the image signals of the image sensor ( 3 ) and the adjustment of the position depending on the evaluation of the image signals of the image sensor ( 3 ) he follows. A method according to claim 10 or 11, characterized in that after fixing the position of the lens ( 10 ) in the lens holder ( 5 ) an in situ check of the camera module ( 1 ) by evaluation of image signals of the image sensor ( 3 ) he follows. Method according to one of claims 10 to 12, characterized in that the positioning of the lens ( 10 ) in the lens holder ( 5 ) by an axial displacement without thread rotation. Method according to one of Claims 10 to 13, characterized in that, during the positioning, an adjustment of the azimuth angle of the objective ( 10 ) in the lens holder ( 5 ) he follows.

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