KR20210125163A - Assembly Structure for Vehicle Camera Module Using Solder Jet and Having Unibody Lens Housing - Google Patents

Abstract

The present invention relates to an assembly structure for a lens-integrated vehicle camera module using solder jet to precisely fix lenses and image sensors in which optical alignment is completed. According to the present invention, the assembly structure comprises: a plurality of lens elements forming a lens of a vehicle camera module; a circuit board including an image sensor; a front housing having a lens barrel structure, in which a plurality of lens elements are assembled, integrally formed on the front side and having a circuit board assembled on the rear side; and a rear housing coupled to the rear side of the front housing to seal the lens and the circuit board. The front housing includes a plurality of posts protruding to the rear side and pins protruding from an end surface of each post with a smaller cross-sectional area than that of the post. The circuit board includes plating through-holes at least partially receiving each of the pins, respectively. The front housing and the circuit board are temporarily assembled so that the pin and the plating through-hole have a predetermined assembly gap, the lens and the image sensor are optically aligned in the tentatively assembled state, the assembly gap is soldered with a laser solder jet bonding process, and thus the vehicle camera module is fixed.

Description

Assembly Structure for Vehicle Camera Module Using Solder Jet and Having Unibody Lens Housing

The present invention relates to an assembly structure of a camera applied to a vehicle. More specifically, it relates to an assembly structure after optical alignment of a lens and an image sensor using a solder jet.

The content described in this section merely provides background information for the present embodiment and does not constitute the prior art.

Recently released cars include at least one camera, and the more advanced the car, the more cameras are used. For example, in the case of a vehicle equipped with a parking assistance system, the number of cameras mounted in order to photograph a wider range around the vehicle is increasing.

Cameras are an essential component of Advanced Driver Assistance Systems (ADAS) and autonomous vehicles. Examples of ADAS include Autonomous Emergency Braking (AEB), Forward Collision Assist (FCA), Forward Collision Warning (FCW), Lane Keep Assist (LKA), and Lane Keep Assist (LKA). Lane Departure Warning (LDW), Lane Following Assist (LFA), Lane Keeping Assistant System (LKAS), Active Blind Spot Detection (ABSD), Around View Monitoring ( There are Around View Monitoring (AVM), Low Beam Assist (LBA), Driver Attention Warning (DAW), and Smart Cruise Control (SCC).

According to the National Highway Traffic Safety Administration (NHTSA), major automakers are planning to introduce the front collision warning function and automatic brake function as basic specifications for new cars from 2022. A camera is a major component of an autonomous driving system along with radar and LiDAR (Light Detection and Ranging). Obstacles, lanes, road signs, traffic signals, etc. are often more advantageous to be detected by a camera than by radar or lidar.

The vehicle camera is supplied in the form of a single module in which an image sensor and a lens are assembled. The optical axis alignment state may be changed in the process of attaching the image sensor to the circuit board or in the process of assembling the plurality of lens elements to the lens barrel. If an inaccurate image is provided due to a misaligned optical axis, the performance of the parking guide or automatic driving is deteriorated. Therefore, each camera module is subjected to 6-axis optical alignment before fixing the lens and the image sensor to each other to ensure optical performance (see Patent Documents 1 and 2).

On the other hand, a polymer adhesive is mainly used for fixing after alignment. The resin adhesive has characteristics such as dimensional change in the curing process, a slow curing rate, and a low glass transition temperature. Dimensional changes and slow cure rates reduce quality and productivity. If the operational temperature of the camera is close to the glass transition temperature of the resin adhesive, the adhesive portion may be deformed and the optical axis alignment precision may be deteriorated. Therefore, in order to provide a high-performance camera module with high reliability, an improved camera assembly structure capable of ensuring accurate optical axis alignment is required.

1 is an exploded perspective view showing an assembly structure of a conventional camera module.

Referring to FIG. 1 , the automotive camera modules 1 and 1 ′ include a lens 10 , a front housing 20 , a circuit board 30 and a rear housing 50 disposed from the front to the rear close to the shooting area. include

The lens 10 is assembled by fixing the plurality of lens elements 100 in the lens barrel 110 , and closing the front of the lens barrel 110 with a retainer 120 . The lens 10 is pre-assembled in the front housing 20 , and the image sensor 40 is mounted on the circuit board 30 . The front housing 20 and the circuit board 30 are assembled after being optically aligned so that an assembly error between the lens 10 and the image sensor 40 is corrected. The camera modules 1 and 1 ′ are accommodated and sealed in the front housing 20 and the rear housing 50 so that the lens 10 and the circuit board 30 are prevented from being contaminated by the external environment.

High-resolution image sensors are so precise that the pixel pitch is only a few microns. On the other hand, the portion in which the plurality of lens elements 100 , the lens barrel 110 , the front housing 20 , the image sensor 40 and the circuit board 30 are assembled with each other is compared with the resolution of the image sensor 40 . It contains a relatively large assembly error. In general, the image sensor 40 forms a BGA (Ball Grid Array, not shown) on the circuit board 30 and is soldered by a reflow process. In this process, non-uniform deformation of the BGA, etc. Due to this, the position of the image sensor 40 may be shifted. Even when it is attached through a conductive adhesive (not shown), the alignment state may be changed as well.

If the lens 10 and the image sensor 40 are not accurately aligned, the camera modules 1 and 1 ′ obtain a distorted image. That is, the optically misaligned camera modules 1 and 1 ′ reduce the reliability of ADAS functions that require accuracy, such as a parking guide or an automatic driving function. Precise optical alignment is preferably performed before the lens 10 and the image sensor 40 are fixed. For accurate optical alignment, a master chart (not shown) including a test pattern for calibration is disposed in front of the lens 10 , and alignment error using the image of the image sensor 40 . 6-axis optical alignment can be performed by identifying

When the resin adhesives 91 and 92 previously applied to the bonding site are cured in a state where the optical alignment is completed, the lens 10 and the image sensor 40 are finally fixed. Figure 1 (a) is a case in which the lens barrel 110 and the front housing 20 are assembled before optical alignment, Figure 1 (b) is the front housing 20 and the circuit board 30 before the optical alignment Each case is shown when assembled in The resin adhesives 91 and 92 may be applied between the rear of the front housing and the circuit board as shown in FIG. 1 (a), or may be applied between the front of the front housing and the rear of the lens barrel as shown in FIG. can

The resin adhesives 91 and 92 may be a material that is UV cured or heat cured. Alternatively, after UV curing first, thermal curing may be performed secondarily. Specifically, after temporary curing by UV curing and fixing, the cameras 1 and 1 ′ are removed from the optical alignment platform (not shown), and then the resin is cured by thermal curing in an oven.

Although UV curing has a fast curing speed, when applied to a narrow assembly gap of opaque parts such as the lens barrel 110, the front housing 20, and the circuit board 30, the UV light is properly irradiated to the inside of the gap It can be difficult to be illuminated. Thermal curing takes a considerable amount of time to cure, and heat is transferred to surrounding parts in addition to the bonding area, causing thermal deformation and may affect the assembly precision of the final assembly. Nevertheless, as a method of fixing the lens 10 and the image sensor 40 after performing 6-axis optical alignment, a method using the resin adhesives 91 and 92 is more advantageous than a mechanical assembly method. This is because the required 6-axis optical alignment precision is so high that stress effects due to mechanical assembly are difficult to exclude.

On the other hand, the UV curable resin and the thermosetting resin undergo polymerization and change in volume to some extent during the curing process. As a result, residual stress may remain at the bonding site, and the optical alignment state may be misaligned. In addition, recent automobile cameras are required to guarantee operation at a high temperature of, for example, 85°C, which is higher than the conventional 75°C level. When the bonding site is close to the glass transition temperature of the resin adhesives 91 and 92, a volume change may occur as the distance between the polymer chains of the resin adhesives 91 and 92 increases, and when exposed to high temperature for a long time, permanent deformation may occur have. That is, when the image sensor 40 becomes high resolution and the operation guarantee temperature increases, the use of the resin adhesives 91 and 92 may not be desirable.

Korean Patent Registration No. 10-1409322 (2014.06.12) Korea Patent Publication No. 10-2018-0000126 (2018.01.02)

Embodiments of the present invention provide an assembly structure of a camera module for a vehicle that can precisely fix a lens and an image sensor with optical alignment completed, and can obtain a high-quality image with small deformation even in a high-temperature operating environment of, for example, 85 ° C. The main purpose is to

In order to solve the above problems, a camera module for a vehicle according to an embodiment of the present invention, a plurality of lens elements constituting the lens of the camera module for a vehicle; a circuit board including an image sensor; a front housing in which a lens barrel structure in which a plurality of lens elements are assembled in the front is integrally formed, and a circuit board is assembled in the rear; and a rear housing coupled to the rear of the front housing to seal the lens and the circuit board, wherein the front housing includes a plurality of posts protruding to the rear, and pins protruding each having a smaller cross-sectional area than the post on the longitudinal surface of each post. The circuit board includes a plating through hole at least partially accommodating each of the pins, and the front housing and the circuit board are temporarily assembled so that the pin and the plating through hole have a predetermined assembly gap, The image sensor is characterized in that optical alignment is performed and fixed by soldering the assembly gap using a laser solder jet bonding process.

In addition, the optical alignment is characterized in that it is performed by finely moving the front housing to which the lens is assembled or the circuit board on which the image sensor is mounted in 6-axis directions.

In addition, the assembly gap is defined as the gap between the end face of the post and the front face of the circuit board and the gap between the pin and the plating through hole, and to allow fine movement in the 6-axis direction required for optical alignment of the lens and the image sensor. characterized in that it is formed.

In addition, the plating through hole is characterized in that the electrolytic gold plating.

In addition, the pin is characterized in that it is nickel-plated.

In addition, the laser solder jet bonding process is characterized in that it is a process using a Sn-Bi-based solder ball.

In addition, the solder ball is characterized in that the Sn-58Bi alloy material.

In addition, the plurality of lens elements include a first lens group disposed in front of the lens and a second lens group disposed at the rear of the lens, wherein the second lens group is assembled to the lens barrel structure, and the first lens group includes the lens of the lens. It is characterized in that it is assembled to a retainer assembled in the front.

In addition, it is characterized in that the angle of view of the lens can be changed by changing the optical configuration of the first lens group with respect to the same second lens group.

After the optical axes of the image sensor and the lens are aligned in the vehicle camera module according to the embodiment of the present invention, a gap between the temporary coupled parts is filled with a solder ball using a laser solder jet bonding process. Fill it with a ball) and fix it. A temporary coupling gap is formed between a plurality of pins formed at the rear of the front housing and plated through-holes of a circuit board for accommodating these pins. The gap is filled with a solder ball, a metal material, and instantly solidified, so that the alignment of the optical axis before and after the assembly process is ensured, and it has the effect of providing a high operation guarantee temperature.

In addition, since the structure corresponding to the lens barrel to which the lens group is coupled is integrally formed in the front housing, the assembly process is shortened and the probability of an assembly error occurring is reduced.

1 is an exploded perspective view showing an assembly structure of a conventional camera module.
2 is an exploded perspective view showing the components of the camera module according to the first embodiment of the present invention.
3 is a perspective view showing the assembly structure of the front housing and the circuit board according to the first embodiment of the present invention.
4 is a conceptual diagram illustrating a laser solder jet bonding process for fixing the camera module assembly structure according to the first embodiment of the present invention.
5 illustrates a pin of the front housing and a plating through hole of a circuit board according to the first embodiment of the present invention.
6 illustrates an assembly tolerance between a pin and a plating through hole in consideration of optical alignment of the camera module according to the first embodiment of the present invention.
7 is a perspective view showing a coupling method of the front housing and the rear housing according to an embodiment of the present invention.
8 is an exploded perspective view showing components of a camera module according to a second embodiment of the present invention.
9 is an exploded perspective view illustrating a front housing in which a structure corresponding to a lens barrel according to a second embodiment of the present invention is integrally formed therein.
10 is a perspective view illustrating embodiments of pin parts separately assembled to a front housing according to a third embodiment of the present invention.
11 illustrates embodiments of a pin component in the form of being inserted and coupled to a boss of a front housing according to a third embodiment of the present invention.
12 illustrates embodiments in which a plating shell is inserted and coupled to a pin protruding from the front housing according to the third embodiment of the present invention.
13 illustrates embodiments of a pin co-injected into a front housing according to a third embodiment of the present invention.
14 illustrates embodiments of a pin having a polygonal head shape according to a fourth embodiment of the present invention.
15 illustrates an embodiment of a pin having a head shape in which the cross-section decreases toward the end according to the fifth embodiment of the present invention.
16 illustrates an assembly structure in which a screw is screwed to a boss of a front housing according to a sixth embodiment of the present invention.
17 illustrates the assembly tolerance of the plating through hole and the screw according to the sixth embodiment of the present invention.
18 is a perspective view illustrating an assembly structure using corners of a circuit board according to a seventh embodiment of the present invention.
19 is a perspective view illustrating an assembly structure using a side portion of a circuit board as a modified example of the seventh embodiment of the present invention.
20 illustrates an assembly structure including a plating through hole formed so that the gap becomes wider as it approaches the solder ball entry part according to the eighth embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and the essence, order, or order of the components are not limited by the terms. Throughout the specification, when a part 'includes' or 'includes' a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated. . In addition, the '... Terms such as 'unit' and 'module' mean a unit that processes at least one function or operation, which may be implemented as hardware or software or a combination of hardware and software.

The present inventors, in the camera module for a vehicle, in order to mutually fix the front housing 20 on which the lens 10 is assembled and the circuit board 30 on which the image sensor 40 is mounted, instead of the resin adhesives 91 and 92 An assembly structure and method using a method of fixing with a solder ball by solder jet was devised. This structure has high assembly precision, productivity and operation guarantee temperature.

2 is an exploded perspective view showing the components of the camera module according to the first embodiment of the present invention.

Referring to FIG. 2 , the camera module 2 according to the first embodiment of the present invention includes a lens 10 , a front housing 21 , a circuit board 30 , and a rear housing 50 . A plurality of pins 200 are included in the rear of the front housing 21 , and a plating through hole 300 accommodating each of the plurality of pins 200 is formed in the circuit board 30 . The pin 200 and the plating through hole 300 are provisionally coupled and formed to provide a sufficient gap for the 6-axis optical alignment to be performed.

3 is a perspective view showing the assembly structure of the front housing and the circuit board according to the first embodiment of the present invention.

Referring to FIG. 3 , the plurality of pins 200 and the plurality of plating through-holes 300 are illustrated in a case in which three are arranged in pairs, but the present invention is not limited thereto and may be four or more, and a smaller number is formed. could be

4 is a conceptual diagram illustrating a laser solder jet bonding process for fixing the camera module assembly structure according to the first embodiment of the present invention.

According to an embodiment of the present invention, the temporary coupling part gap 310 is melted by a laser 944 using a laser solder jet bonding process as shown in FIG. 4 and a solder ball 942 sprayed by a compressed gas 946 . is fixed by Referring to (b) of FIG. 3, the lens 10 and the image sensor 40 are temporarily assembled so that the rear of the circuit board 30 is upward, and can be disposed on a platform (not shown) on which 6-axis optical alignment is performed. have. Laser solder jet bonding equipment (not shown) may be disposed to be spaced apart from the rear of the circuit board 30 . The laser solder jet bonding equipment may be mounted on a drive system (eg, a robot arm, not shown) capable of 5-axis movement so as to spray the solder balls 942 at an arbitrary position at an arbitrary angle. In addition, the laser solder jet bonding equipment is provided with the same number as the plating through-holes 300 to minimize the movement of the drive system, thereby improving productivity.

5 illustrates a pin of the front housing and a plating through hole of a circuit board according to the first embodiment of the present invention.

6 illustrates an assembly tolerance between a pin and a plating through hole in consideration of optical alignment of the camera module according to the first embodiment of the present invention.

5 and 6 , the through hole of the circuit board 30 accommodating the pin 200 is formed as a plating through hole 300 . The plurality of pins 200 are in the form of two-stage cylindrical columns protruding from the rear of the front housing 21 . A pin portion 204 accommodated in the plating through hole 300 of the circuit board 30 is formed at the end of a cylindrical post 202 having a larger diameter than the diameter of the pin portion 204 . , a liquid solder ball 942 that is sprayed from the nozzle 940 at a position spaced apart from the rear of the circuit board 30 and penetrates into the gap between the plating through hole 300 and the pin 200 is the annular shape of the post 202 . Only the gap 312 between the phosphor side 203 and the front of the circuit board 30 and the gap 310 between the pin portion 204 and the inner surface of the plating through hole 300 may be filled.

Since the plating through hole 300 according to an embodiment of the present invention is used for the purpose of structurally coupling the front housing 21 and the circuit board 30, it is preferable to be electrolytic gold-plated with high peel strength. can, but is not limited thereto. In addition, the plurality of pins 200 may be nickel-plated to facilitate soldering.

The height of the post 202 may be selected in consideration of the focal length of the lens 10 , the distance between the lens 10 and the image sensor 40 , and the like. Six-axis optical alignment is accomplished through fine translation in the X, Y, and Z directions, and fine rotation around the X, Y, and Z axes (e.g., roll, yaw, pitch). do. The gaps 310 and 312 between the plating through hole 300 and the pin 200 may be selected in consideration of the required 6-axis fine adjustment amount.

6-axis optical alignment is, for example, by disposing the lens 10 so that the front faces the lower part of the platform for optical alignment, and disposing a master chart including a test pattern for calibration in front of the lens 10, It can be performed by analyzing the image obtained from the image sensor 40 mounted on the circuit board 30 , calculating the amount of position correction, and correcting by moving the circuit board 30 by 6 axes accordingly.

When the optical alignment is completed, the assembly of the front housing and the circuit board is completed by filling the solder balls 942 into the gaps using laser solder jet bonding equipment and solidifying them. The size of the solder ball 942, the temperature before injection of the solder ball 942, the angle of incidence of the solder ball 942, the distance between the nozzle and the gap, etc. may be selected in consideration of the structure and thermodynamic characteristics of the pin and the plating through hole. The diameter of the solder ball 942 injected from the nozzle of the laser solder jet bonding equipment may be, for example, 0.9 to 1 mm.

The solder ball 942 is heated by a laser 944 and sprayed from the nozzle 940 in a liquid state to locally increase the temperature of the area to be soldered between the pin 200 and the plating through hole 300, and the gap 310, 312) and then solidifies at a fast rate. This process is instantaneous in a very short time, and the volume change of the solidified solder ball 942 according to the temperature drop to room temperature is at least 1/3 times smaller than that of the resin adhesives 91 and 92 .

As a material of the solder ball 942, a material having a low melting point is preferred, and a Sn-Bi-based material having a melting point of 139°C may be used. This is a relatively low temperature as a solder material, but is high enough to be applied to an automotive camera module and used at a guaranteed operation temperature, for example, 85°C. Specifically, the material of the solder ball 942 may be a Sn-58Bi alloy. The thermal expansion coefficient of Sn-58Bi is 15x10 ^-6 /℃.

The Sn-Bi-based alloy has a spreading ratio of about 78-80% in the range of 220-250 ℃, and a contact angle of about 18°. Such a high spreading rate and a low contact angle are characteristics suitable for penetration of the solder ball 942 into the gap 310 between the pin 200 and the plating through hole 300 . A solder material having a high melting point, for example, 250 ° C. or higher, is preferable because such a low-melting-point solder may result in a decrease in joint strength and fatigue failure due to disadvantages such as deterioration of the circuit board material and excessive growth of the metal compound layer in the solder joint. can do.

In addition, the Sn-Bi-based solder material has a relatively higher yield strength than the Sn-Pb or Sn-Ag-Cu-based solder material. However, although the elastic deformation region is narrow and brittleness is slightly increased, it may not be a problem in the case of this embodiment used in the form of filling in a narrow gap. Since the Sn-Bi material has a relatively wide solidification range, for example, 139 to 190° C., when the solder solidifies, the time for coexistence of the solid/liquid phase is long and segregation is highly likely to be formed. On the other hand, in the case of the present embodiment, the solder balls 942 filled in the gaps 310 and 312 between the pin 200 and the plating through-hole 300 are thinly spread and cooled relatively rapidly, leaving the solidification temperature range quickly, resulting in may not increase brittleness.

On the other hand, each of the plurality of pins 200 and the plating through hole 300 may have different clearance gaps after 6-axis optical alignment. For example, a larger gap may be formed in a specific direction around the fin 200 . In consideration of this, an inspection camera (not shown) for monitoring the alignment state of the pin 200 and the plating through hole 300 may be additionally disposed at the rear of the circuit board 30 on which the 6-axis optical alignment is made. The inspection camera grasps the state of the gap formed by each of the pin 200 and the plating through hole 300 as a result of the alignment. The laser solder jet bonding equipment may be formed to be capable of 5-axis movement, and the position and angle at which the solder ball 942 will be sprayed may be optimized in consideration of each gap detected by the inspection camera.

The fixing method using the laser solder jet bonding process according to an embodiment of the present invention is advantageous compared to the resin adhesives 91 and 92 in the following points.

When the resin adhesives 91 and 92 are used, the 6-axis optical alignment platform includes a dispenser (not shown) for adhesive application, and a UV irradiator (UV illuminator, not shown) that irradiates ultraviolet rays for UV curing. is composed An oven (not shown) for thermal curing is additionally required in order to secure the required bonding strength. On the other hand, the laser solder jet bonding apparatus according to an embodiment of the present invention can be easily installed on a 6-axis optical alignment platform as long as the nozzle 940 can be located at a position appropriately spaced from the circuit board 30. .

In particular, compared with the time required for adhesive application, UV curing, etc., the solder ball 942 can be instantaneously completed so quickly that the gap injection and solidification are incomparable with the resin adhesives 91 and 92 . Accordingly, the possibility that the alignment state before and after fixing is changed is significantly reduced.

In general, the solder jet applied to the gap is more difficult to secure process quality than the solder jet applied to a flat electrode pad or exposed lead pins. For example, when the assembly gap is narrow as in the case of assembling the camera module according to an embodiment of the present invention, it may not be easy to uniformly fill the solder ball 942 in the gap. In addition, in the case of an embodiment of the present invention applied to a fin 200 having a relatively large heat capacity compared to a small electrode pad on a flat substrate to which a laser solder jet bonding process is mainly applied, there is a possibility that cold soldering occurs. An improved type of assembly structure for securing solder jet quality will be further described with reference to the following examples.

7 is a perspective view showing a coupling method of the front housing and the rear housing according to an embodiment of the present invention.

When the optical axis alignment of the lens 10 and the image sensor 40 is completed, the front housings 21 and 22 and the rear housing 50 are assembled, and the coupling part between the front housings 21 and 22 and the rear housings 50 and 52 is completed. By sealing the (500, 520), the assembly of the vehicle camera module (2, 2') is completed. For example, when the front housings 21 and 22 and the rear housings 50 and 52 are made of metal, the coupling portions 500 and 520, which are the assembly boundaries between the front housings 21 and 22 and the rear housings 50 and 52, are laser welded. Sealing can be completed using

When the coupling part 500 of the front housing 21 is substantially rectangular as shown in FIG. ) according to the rotation of the camera module (2) to correspond to the welding position can be adjusted to the distance to the welding site. On the other hand, the exterior of the front housing 22 and the rear housing 52 may be formed in a cylindrical shape as shown in (b) of FIG. The camera module 2' is rotated about the optical axis 96' and the laser welding can be performed in a fixed state without a separate focus position adjustment, so that the process can be simplified.

8 is an exploded perspective view showing components of a camera module according to a second embodiment of the present invention.

Referring to FIG. 8 , in the front housing 23 according to the second embodiment of the present invention, the lens barrel structure 240 corresponding to the lens barrel 110 is integrally formed. The plurality of lens elements 100 are mounted on the lens barrel structure 240 provided in the front housing 23 , and the retainer 120 is assembled in front of the front housing 23 , so that the front housing 23 and the lens 10 are assembled. ) are integrated into one.

9 is an exploded perspective view illustrating a front housing in which a structure corresponding to a lens barrel according to a second embodiment of the present invention is integrally formed therein.

Referring to FIG. 9 , since the lens 10 is directly assembled to the front housing 23 , the assembly process may be simplified and assembly errors may be reduced compared to the first embodiment of the present invention. In the case of the first embodiment, after the plurality of lens elements 100 are assembled to the lens barrel 110 , the lens barrel 110 is assembled to the front housing 21 and optical axis alignment with the image sensor 40 is performed. In the case of the second embodiment, since the plurality of lens elements 100 are assembled to the lens barrel structure 240 of the front housing 23 and then the optical axis alignment with the image sensor 40 is performed, the assembly area is reduced, resulting in assembly errors. can decrease.

Meanwhile, although not illustrated, the plurality of lens elements 100 may be divided into a first lens group and a second lens group. The first lens group disposed in front of the lens may be configured in various forms so that the angle of view of the lens is changed. The second lens group disposed behind the lens may have the same shape. That is, by changing the first lens group with respect to the same second lens group, the lenses can be configured with various angles of view.

In general, a zoom lens may change an angle of view by moving a plurality of lens elements into different groups and moving inside the lens. Alternatively, the angle of view may be changed by changing the shape of some of the inner lens groups.

On the other hand, in a camera module for a vehicle, which is a generally wide-angle lens, the image is compressed toward the rear of the lens. That is, an assembly error of the lens element disposed at the rear of the lens may have a greater effect on the quality of a photographed image.

In one embodiment of the present invention, a common module is provided by assembling the second lens group to the lens barrel structure 240 of the front housing 23, and by assembling the first lens group of various types to the common module according to the lens angle of view. It is possible to easily manufacture lens modules of various angles of view.

10 is a perspective view illustrating embodiments of pin parts separately assembled to a front housing according to a third embodiment of the present invention.

Referring to FIG. 10 , the front housing 24 according to the third embodiment of the present invention has a structure in which a separately manufactured pin 600 is inserted into a boss 240 of the front housing 24 . The boss 24 has a structure in which a cylindrical column is formed at the rear of the front housing 24 and a hole for assembly with the pin 600 is formed at the end of the cylindrical column.

According to an embodiment of the present invention, the front housing 24 to which the lens 10 is assembled and the circuit board 30 including the image sensor 40 are bonded by a laser solder jet bonding process after optical alignment. In order to ensure the soldering quality, an appropriate temperature rise is required on the surfaces of the two materials in the soldering area. If the surface temperature does not rise to an appropriate level due to excessive heat transfer in the soldering area, cold solder may occur, which may not provide adequate joint strength.

In the coupling portion between the fin 600 and the boss 240 , the area in which heat transfer occurs is substantially narrowed. Even when the front housing 24 is made of a metal material, the coupling portion between the pin 600 and the front housing 24 may have lower thermal conductivity than when the front housing 24 is integrally formed. Accordingly, the coupling portion between the fin 600 and the boss 240 according to the third embodiment of the present invention may delay heat transfer compared to the case where the fin shape is integrally formed with the front housing 24 . Accordingly, the separately inserted pin 600 may substantially reduce the heat capacity of the soldering portion, and the temperature of the soldering portion may be appropriately increased by the solder ball 942 , thereby preventing cold soldering. In addition, the pins 600 may be surface finished differently from the front housing 24 to provide surface properties suitable for solder jet bonding.

Meanwhile, since the pin 600 may be separately inserted, the front housing 24 may not be a metal material suitable for soldering. For example, the front housing 24 may be a non-metallic material such as plastic. When the front housing 24 is formed of a plastic material, heat transfer from the fins 600 during soldering can be made smaller, and as a result, cold soldering can be prevented.

11 illustrates embodiments of a pin component in the form of being inserted and coupled to a boss of a front housing according to a third embodiment of the present invention.

The pin 600 may be in the form of a plunger pin including a boss coupling portion 602 , a flange portion 604 , and a mating portion for plated through-hole 606 . Referring to FIG. 11 , the shape of the pins 600 , 610 , 620 , 630 inserted and coupled to the boss 240 , which is a cylindrical column shape of the front housing 24 , is a boss coupling part 602 that is press-fitted, a screw It may be any one of the boss coupling part 612 to be coupled, the boss coupling part 622 to be ultrasonically coupled, and the boss coupling part 632 press-fitted by elastically deforming the cut-out portion in the axial direction.

12 illustrates embodiments in which a plating shell is inserted and coupled to a pin protruding from the front housing according to the third embodiment of the present invention.

Alternatively, referring to FIG. 12 , as for the pin 640 , a pin portion 644 into which a plated bush 642 can be inserted is formed on the post 646 , and the bush 642 is a pin portion 644 . ) after being inserted on the pin portion 644 may be of a form coupled by caulking (caulking). On the other hand, unlike this, the pin 650 has a shape in which the pin portion 652 is cut in the axial direction to be elastically deformed, and after the bush 642 is inserted into the pin portion 652, the tip of the pin portion 652 is It may be in the form of being fixed by a hook structure (654) of the. In these embodiments, the heat capacity of the plated bush 642 is lower than that of the embodiment of FIG. 11 , which is advantageous for the laser solder jet bonding process.

13 illustrates embodiments of a pin co-injected into a front housing according to a third embodiment of the present invention.

Referring to FIG. 13 , when the front housings 25 and 26 are injection-molded from, for example, a plastic material, the pin members 660 and 670 are pre-fabricated from a metal material and then the front housing 25, 26) can be molded to be included within. The pin member 660 may be formed integrally with a plurality of pins as shown in (a) of FIG. 13, or the pin member 670 may be formed such that a plurality of pins are individually included as shown in (b) of FIG. 13 . have.

14 illustrates embodiments of a pin having a polygonal head shape according to a fourth embodiment of the present invention.

14 (b) to 14 (d), the shape of the plating through-hole coupling portion 606 of the pins 710, 720, 730 separately assembled to the front housing 24 has a polygonal cross section in addition to the cylindrical shape. It may be in the form of branches. Since the plating through-hole coupling portions 716 , 726 , and 736 of the pins 710 , 720 and 730 are formed in polygonal cross-sections, a wide gap can be formed locally while being accommodated in the circular plating through-hole 300 . The laser solder jet bonding equipment may be controlled to inject the liquid solder ball 942 into the gap formed locally as wide.

14(e) to 14(h), plating through-hole coupling parts 746, 756, 766 of pins 740, 750, 760, and 770 that are separately manufactured and assembled to the front housing 24 , 776) shape may be in the form of a cavity (cavity) is formed on the inside. When the volume of the plating through-hole coupling portions 746, 756, 766, 776 of the pins 740, 750, 760, and 770 is reduced using the cavity, the soldered portion of the pins 740, 750, 760, 770 Cold soldering is prevented by reducing the heat capacity, and consequently, soldering quality can be improved. On the other hand, the shape of the cavity may be a shape in which a hex wrench, a star wrench, a Phillips screwdriver, etc. are inserted and a standard tool can be used when assembling the pin.

15 illustrates an embodiment of a pin having a head shape in which the cross-section decreases toward the end according to the fifth embodiment of the present invention.

15, the shape of the plating through-hole coupling portions 816, 826, 836 of the pins 810, 820, and 830 according to the fifth embodiment of the present invention is a pin to facilitate the entry of the liquid solder ball 942. The gap between the 810 , 820 , and 830 and the plating through hole 300 may be widened in the nozzle direction of the laser solder jet bonding equipment or may be formed in a wide nozzle direction.

Referring to (b) of FIG. 15 , the plating through-hole coupling portion 816 of the pin 810 may have a shape substantially similar to a crown. That is, the end of the plating through-hole coupling portion 816 is formed in a concave-convex shape along the outer circumferential surface, so that the area into which the solder ball 942 enters is substantially widened.

Referring to (c) of Figure 15, the plating through-hole coupling portion 826 of the pin 820 has a shape in which two inclined surfaces are gathered at one edge at the end of the plating through-hole coupling portion 826, for example, a flat-head screwdriver. (flat head screwdriver) shape. As another modified form, as shown in (d) of FIG. 15 , the plating through-hole coupling portion 836 of the pin 830 has three inclined surfaces gathered at one point at the end of the plating through-hole coupling portion 836 . can be

Also, although not shown, the end of the plating through-hole coupling portion of the pin may be formed in the shape of a Phillips screwdriver head. In addition to this, the shape of the pin according to the fifth embodiment of the present invention is a liquid solder ball ( 942) should be understood to include other forms that can easily enter the gap.

16 illustrates an assembly structure in which a screw is screwed to a boss of a front housing according to a sixth embodiment of the present invention.

Referring to FIG. 16 , the front housing according to the sixth embodiment of the present invention includes a hole formed in the rear so that a screw can be coupled thereto. A hole may be formed at the end of the cylindrical column protruding from the rear of the front housing. The hole may be threaded in advance, or may be assembled while forming a thread on the inner circumferential surface of the hole when the screw is coupled in a non-threaded state.

To prevent loosening after assembly, for example, a thread locker such as Loctite® may be pre-applied to the threaded portion to be inserted into the screw hole. In order for the solder ball 942 to fill the space between the thread and the plating through hole to achieve proper soldering, it is preferable that Loctite® is not applied to the area to be soldered after optical alignment.

17 illustrates the assembly tolerance of the plating through hole and the screw according to the sixth embodiment of the present invention.

According to the sixth embodiment of the present invention, after the circuit board 30 is disposed at the rear of the front housing 24 , the screw 840 is inserted through the plating through hole to the hole (or screw hole) of the boss 240 . ) and screwed together. Referring to FIG. 17 , the screws 840 are assembled to a level that provides sufficient clearance for optical alignment of the front housing 24 and the circuit board 30 . The screw 840 and the circuit board 30 are firmly fixed to each other by being soldered by a solder ball 942 injected into a gap between the screw head 842 and the rear surface of the circuit board 30 . The screw 840 may be made of a material that is easy to solder, for example, a material of brass.

According to the sixth embodiment of the present invention, since the soldering screw 840 is made of a metal material, the front housing 24 does not necessarily have to be a metal material. In addition, the process of assembling the screw 840 to the boss 240 of the front housing 24 is very easy to automate. That is, the assembly structure according to the sixth embodiment is characterized in that the productivity of the assembly process is very high.

Meanwhile, although the sixth embodiment exemplifies a case in which a screw 840 having a screw head is used, a set screw may also be used. Among the headless bolts, for example, when a socket set screw is used, as described in the fourth embodiment of the present invention, it has a cavity in the head, so that the heat capacity of the soldering area is reduced and cold soldering is prevented. effect can be expected. In addition, the headless bolt can be screwed in advance to the boss 240 of the front housing 24 before the circuit board is temporarily assembled, so that process design can be easy.

18 is a perspective view illustrating an assembly structure using corners of a circuit board according to a seventh embodiment of the present invention.

Referring to FIG. 18 , the camera module assembly structure according to the seventh embodiment of the present invention is formed to solder the outer rim of the circuit board 31 and the inner gap of the front housings 27 and 28 using a laser solder jet bonding process. . The circuit board 31 is formed to be accommodated in a pocket portion formed at the rear of the front housings 27 and 28 with an assembly gap for optical alignment. After disposing the front housings 27 and 28 to which the lens 10 is assembled on the 6-axis optical alignment platform, the circuit board 31 on which the image sensor 40 is mounted is disposed to perform optical alignment. After the optical alignment is completed, the assembly gap is soldered by injecting the solder ball 942 into a plurality of positions.

Referring to FIG. 18A , a plurality of posts 850 having a generally rectangular cross section are formed on the rear of the front housings 27 and 28 . The circuit board 31 is processed so as to have an assembly gap with the plurality of posts 850, and the side of the edge portion forming the assembly gap with the plurality of posts 850 is plated to facilitate soldering, so that the plated sidewall (plated) is plated. side wall, 314) is formed. The assembly gap formed by the plurality of posts 850 and the plating sidewall 314 is soldered by a solder ball 942 after optical alignment.

Referring to FIG. 18B , the plurality of posts 860 may have a cylindrical shape. The outer circumferential surface of the cylindrical post 850 and the two planar plating sidewalls 314 form a minimum assembly clearance at two points, and the assembly clearance increases as the distance from the two points increases.

The laser solder jet bonding process may be input at an oblique angle toward the assembly gap in consideration of the minimum assembly gap, the diameter of the post 850 and the diameter of the solder ball 942 . For example, the injection angle of the solder ball 942 of the nozzle 940 is such that the point where the input solder ball 942 first contacts the post 850 and the plating sidewall 314 has the same distance from the position where the minimum assembly gap is formed. can be adjusted. The solder ball 942 enters a narrow area from a wide area of the assembly gap, uniformly transfers heat to the post 850 and the plating sidewall 314, fills the inside and solidifies, so that soldering quality can be improved.

On the other hand, although not shown, in the case of the seventh embodiment, in order to reduce the heat capacity of the member to be soldered, a cavity in the form of being depressed inward from the ends of the protrusions 850 and 860 may be formed in a manner similar to that of the fourth embodiment. .

19 is a perspective view illustrating an assembly structure using a side portion of a circuit board as a modified example of the seventh embodiment of the present invention.

19 illustrates a case in which a gap between the side edge 324 of the circuit board 32 and the inner wall 290 of the front housing 29 is soldered.

In the seventh embodiment and its modified embodiments, the mechanism portion (not shown) for six-axis movement of the circuit boards 31 and 32 while optical alignment is performed is, for example, the circuit board 31, using a grip. 32) may be formed to hold at least two portions 326 of the side portions. The gap except for the grip portion 326 may be soldered using a solder ball 942 .

According to the seventh embodiment of the present invention, it is possible to simplify the rear structure of the front housings 27 , 28 , and 29 , thereby securing more space for components and circuits in the circuit boards 31 and 32 . In addition, the heat dissipation performance of the circuit boards 31 and 32 is improved by effectively transferring heat generated from the circuit boards 31 and 32 to the front housings 27 , 28 and 29 .

20 illustrates an assembly structure including a plating through hole formed so that the gap becomes wider as it approaches the solder ball entry part according to the eighth embodiment of the present invention.

Referring to (a) of FIG. 20 , the pin 600 having a cylindrical shape and the plating through hole 300 having a cylindrical hole shape may form a uniform gap as a whole. On the other hand, referring to (b) and (c) of Figure 20, the plating through-holes 320 and 330 according to the eighth embodiment of the present invention are, for example, counterbore and countersink. Having a shape, a gap entrance into which the solder ball 942 is inserted may be formed in a wide shape.

A circuit board including an image sensor is generally made of a multi-layered board, and has a structure of at least six or more layers. The non-cylindrical plating through-holes 320 and 330, such as counterbore and countersink shape, may be formed by laminating the multilayer substrate and then processing it with a suitable tool and then plating. Alternatively, similar to the method of forming a buried via or a blind via, it may be formed by forming different diameters of each through hole to be combined into the plating through hole 300 in the single substrate manufacturing step and stacking them. have.

The eighth embodiment of the present invention is characterized by providing the plating through-holes 320 and 330 having a shape in which the solder ball 942 enters the gap is wide and the gap becomes narrower as it goes inside. The liquid solder balls 942 sprayed from the nozzles of the laser solder jet bonding equipment will generally have a droplet shape, and the diameter of the solder balls 942 may be larger than a gap into which the solder balls 942 are injected. By forming the inlet of the gap larger than that of the inner gap, the solder ball 942 can be easily entered into the gap.

The solder balls 942 sprayed by the solder jet method enter the gap with a predetermined speed. Since the volume of the gap decreases as the solder ball 942 filling the opening of the gap enters the inside of the gap, the injected solder ball 942 will spread in the entry direction and to the left and right.

Also, in some cases, when the solder balls 942 are separated from left and right of the pin and filled, a soldering defect corresponding to a cold shut of casting may occur at the innermost side of the gap. Cold shut refers to a casting defect that occurs when the tips of molten materials that have progressed through different paths are cooled prematurely and cannot merge into a liquid phase at the point where they meet. According to this embodiment, since the inlet of the gap has a relatively large volume, solidification is delayed, and the solder ball 942 is filled to the innermost side of the gap in a non-solidified state, cold shut is prevented, and as a result, soldering quality can be improved. have. In addition, since the injection part is wide and a gap is formed in the form of a volume decreasing toward the inside, solidification of the solder ball 942 can be uniformly progressed as a whole, so that the soldering quality can be improved.

The above description is merely illustrative of the technical idea of this embodiment, and various modifications and variations will be possible by those skilled in the art to which this embodiment belongs without departing from the essential characteristics of the present embodiment. Accordingly, the present embodiments are intended to explain rather than limit the technical spirit of the present embodiment, and the scope of the technical spirit of the present embodiment is not limited by these embodiments. The protection scope of this embodiment should be interpreted by the following claims, and all technical ideas within the equivalent range should be interpreted as being included in the scope of the present embodiment.

Claims (9)

a plurality of lens elements constituting a lens of a camera module for a vehicle;
a circuit board including an image sensor;
a front housing in which a lens barrel structure in which the plurality of lens elements are assembled is integrally formed in the front, and the circuit board is assembled in the rear; and
A rear housing coupled to the rear of the front housing to seal the lens and the circuit board,
The front housing includes a plurality of posts protruding backward, and pins each protruding from a longitudinal surface of each of the posts and having a smaller cross-sectional area than the posts,
the circuit board includes a plating through hole at least partially accommodating each of the pins;
The front housing and the circuit board are temporarily assembled so that the pin and the plating through hole have a predetermined assembly gap, and in the temporarily assembled state, the lens and the image sensor are optically aligned, and the laser solder jet bonding process A camera module for automobiles fixed by soldering the assembly gap. According to claim 1,
The optical alignment is
A camera module for a vehicle performed by finely moving the front housing on which the lens is assembled or the circuit board on which the image sensor is mounted in 6-axis directions. 3. The method of claim 2,
The assembly gap is
a gap between the end face of the post and the front face of the circuit board; and
Defined as a gap between the pin and the plating through hole,
A camera module for a vehicle that is formed to allow fine movement in the 6-axis direction required for optical alignment of the lens and the image sensor. According to claim 1,
The plated through hole is an electrolytic gold plated camera module for a vehicle. According to claim 1,
The pin is a nickel-plated camera module for a vehicle. According to claim 1,
The laser solder jet bonding process is a process using a Sn-Bi-based solder ball for an automobile camera module. 7. The method of claim 6,
The solder ball is a Sn-58Bi alloy material for an automobile camera module. According to claim 1,
The plurality of lens elements,
A first lens group disposed in front of the lens and a second lens group disposed behind the lens,
The second lens group is assembled to the lens barrel structure,
The first lens group is a camera module for a vehicle assembled to a retainer assembled in front of the lens. 9. The method of claim 8,
A camera module for a vehicle capable of changing an angle of view of the lens by changing an optical configuration of the first lens group with respect to the same second lens group.

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