WO2013058469A1 - Lens assembly that can be miniaturized and cleaned using liquid, and method for manufacturing same - Google Patents

Abstract

The present invention relates to a lens assembly that configures a camera module mounted on a portable communication terminal, a camera module for a portable communication terminal including the lens assembly, and a method for manufacturing the lens assembly. The lens assembly comprises: a lens unit including lenses for capturing a subject; and a lens barrel for housing the lens unit, wherein the lens having the greatest diameter of the lenses is exposed outside the barrel. According to the present invention, miniaturization of the lens assembly is possible, and in particular, even when foreign substances infiltrate the camera module, water or other liquid can be used to remove the foreign substances and clean the lens assembly.

Description

Lens assembly capable of miniaturization and liquid cleaning and its manufacturing method

The present invention relates to a lens assembly, and more particularly, to a lens assembly constituting a camera module mounted on a mobile communication terminal, a camera module including the lens assembly, and a manufacturing method thereof.

As the multimedia environment is integrated, a camera module for digitally capturing a subject is mounted on a mobile communication terminal. Accordingly, mobile communication terminals such as feature phones, PDAs and smart phones, which are called feature phones, go beyond simple communication functions and function as devices for capturing an image of a subject, that is, a small optical device. In order to capture an image of a subject, a lens assembly is provided at the center of a camera module mounted in a mobile communication terminal. FIG. 1 is a cross-sectional view schematically illustrating a lens assembly constituting a camera module mounted in a conventional mobile communication terminal. 2 is an exploded perspective view schematically illustrating a process of assembling a lens assembly according to the related art.

As shown, the lens assembly 1 according to the prior art is usually accommodated in a lens unit 10 consisting of a plurality of lenses (L1 ~ L4), the lens unit 10 is stacked in the form It consists of a lens barrel 20. When viewed from the subject side, the lens unit 10 is composed of a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. It is manufactured to have proper diameter and curvature for imaging. In addition, spacers 32, 34, and 36 made of a material such as a film are provided to prevent the lenses from being separated from the optical axis and to block unnecessary light, and thus, the first lens L1 and the second lens L2. Is interposed between the second lens L2 and the third lens L3, and between the third lens L3 and the fourth lens L4.

 The subject side of the lens barrel 20 has a hollow portion 22 through which light is transmitted, and the imaging side has a larger hollow portion than the hollow portion 22 at the top to accommodate the lens unit 10 therein. 23 is formed through. As shown in FIG. 2, the plurality of lenses L1 to L4 and the spacers 32, 34, and 36 constituting the lens unit 10 pass through the lens barrel 20 through the hollow 23 at the bottom of the lens barrel 20. When sequentially stacked inside the lens unit 20, the lens unit 10 may be stably assembled into the lens barrel 20 through proper bonding.

Meanwhile, in addition to the lens assembly 1 described above, the camera module for a mobile communication terminal may move the lens assembly 1 in the optical axis direction to perform zooming or auto-focusing of a subject. A drive actuator (not shown) for activating with the lens is disposed along the outer periphery of the lens assembly 1. Also, an image sensor (not shown) having an image forming surface, which is an image forming part of a subject, is used to convert an optical-image of a subject passing through the lens assembly 1 into an electrical signal. Is placed.

The plurality of lenses L1 to L4 disposed inside the lens assembly 1 described above are generally manufactured to have a predetermined curvature through injection molding. The lens unit 10 including the plurality of lenses L1 to L4 and the spacers 32, 36, 38 is housed inside the lens barrel 20 having an inner circumferential surface 24 corresponding to the outer diameter of each lens. . Specifically, the lens unit 10 is housed in the lens barrel 20 as a separate component, which is sequentially stacked into the lens barrel 20 through the hollow 23 at the bottom of the lens barrel 20. do. In this way, the lens units 10 accommodated in the lens barrel 20 are sequentially stacked in a direction perpendicular to the optical axis. A plurality of lenses constituting the lens unit 10 are arranged so that the optical axes of the respective lenses coincide. It is accommodated in the 20, and is assembled stably by applying an adhesive to the outside of the lens unit 10.

In this case, the plurality of lenses L1 to L4 are manufactured to have different curvatures and diameters, and in general, lenses L1 positioned on the subject side have the smallest diameter and gradually larger lenses toward the image plane. . By the way, the lens barrel 20 constituting the conventional lens assembly 1 accommodates the entire lens unit 10 including the plurality of lenses L1 to L4 therein. Therefore, in the case of the conventional lens assembly 1, as a result of assembling the entire lens unit 10 including a plurality of lenses in the state accommodated into the lens barrel 20, the conventional lens assembly 1 is made out of a plurality of lenses. The diameter (R ₁ ) of the fourth lens (L4) of the largest size is bound to have a minimum diameter (D) of the sum of the side width (W) of the lens barrel (20).

However, in response to the trend of mobile communication devices, which are gradually pursuing miniaturization and light weight, the camera module needs to be miniaturized and reduced in weight, and the lens assembly constituting the camera module needs to be manufactured small and light. The structure of the assembly 1 has a limitation in size reduction and weight reduction. In addition, with the development of integrated technology, camera modules mounted in mobile communication terminals are equipped with millions of pixel image sensors. In particular, recently, mobile communication terminals such as smart phones adopting 8 million pixel image sensors have been widely used in the market. have.

As such, as the performance of the image sensor as the image sensor constituting the camera module mounted in the mobile communication terminal increases, that is, a large number of pixels are arranged in the same area, in order to realize a high quality image, By increasing the effective field of view of light incident toward the image plane, more light-images to the subject must be incident on the image sensor. To this end, the effective angle of view through the plurality of lenses L1 to L4 accommodated in the lens barrel 20 must be increased, and thus, the diameters of these lenses L1 to L4 need to be increased.

However, in accordance with the requirements of the mobile communication terminal manufacturers aiming for miniaturization and weight reduction, the diameter of the entire camera module including the drive actuator and the housing disposed around the lens assembly 1 should be downsized to 8.5 mm or less, In particular, the lens assembly 1 should be assembled with a diameter D of 6.5 mm or less. However, in the case of the prior art lens assembly 1 having a diameter D equal to the maximum diameter R ₁ of the lens plus the width W of the lens barrel 20, it is difficult to meet the trend of miniaturization and weight reduction. Do.

In addition, in order to achieve high quality images by adopting an 8 million pixel image sensor, the effective angle of view of the lens should be increased. To this end, the maximum diameter (R ₁ ) of the lens and the diameter (D) of the lens assembly are thus increased. Should be increased. As such, a method of increasing the diameter of the lens assembly 1 and reducing the size of the driving actuator disposed around the outer side of the lens assembly 1 may be considered. However, in this case, it is difficult to achieve a desired driving force. There is concern.

That is, the effective angle of view of the lens must be increased to achieve good image quality by adopting an image sensor of 8 million pixels or more, and for this purpose, the maximum diameter R ₁ of the lens must be larger than the present. However, when the maximum diameter (R ₁ ) of the lens is larger than the present, the diameter (D) of the lens assembly plus the thickness of the lens barrel (W) also increases. Therefore, as long as the diameter of the entire camera module is set, the size of the driving actuator is reduced, so that the desired driving force cannot be obtained. In other words, since it is not possible to reduce the size of the drive actuator to obtain the desired driving force, the diameter D of the conventional lens assembly 1 must also be set to a certain level. Accordingly, the maximum diameter R ₁ of the lens accommodated in the lens assembly ₁ is also fixed to a certain level, and the effective angle of view of the lens cannot be increased. Even if the above image sensor is adopted, it is difficult to realize high quality images.

In addition, when assembling a conventional camera module for a mobile communication terminal, fine foreign matter is generated in the form of particles in the assembly process of the lens assembly 1 or the fastening process of the driving actuator and the housing member formed outside thereof. When such particles are formed in the image capturing region, since the focusing error occurs during the image conversion error in the image sensor and the focus adjustment process on the subject, it is necessary to remove such particles.

As a method for removing foreign substances generated inside the camera module adopted in the conventional mobile communication terminal, the inspector has adopted a method for removing particles checked visually through a microscope. However, the particle removal process is complicated and time-consuming, and it is impossible to remove the generated particles one by one.

Adopting the 'air cleaning' method by the air injection method is also seeking to remove the particles. However, many parts are finely assembled at the bottom of the camera module where the image sensor and the like are arranged. Therefore, if a strong air cleaning to remove the particles completely, there is a risk that many parts are damaged. In order to prevent damage to these parts, only weak air cleaning can be performed, so that the particles cannot be completely removed.

As an alternative to this, a method of removing particles through 'liquid cleaning' using a liquid such as water may be considered. However, in the case of the conventional lens assembly 1, the lens unit 10 is not completely sealed. Water penetrates between the inner circumferential surface of the lens barrel 20 and the outer circumferences of the lenses L1 to L4. As such, when water penetrates into the lens, there is a problem that it is not only possible to adjust the focus of the subject through the lens but also to form an image of the subject accurately with the image sensor, which leads to a defect of the entire camera module. Failed to remove particles through.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a mobile communication terminal having a lens having an effective angle of view enlarged to provide a high quality optical-image with a multi-million-pixel image sensor. To provide a lens assembly, a camera module including the lens assembly and a method of manufacturing the lens assembly.

Another object of the present invention is to provide a lens assembly, a camera module, and a method for manufacturing the lens assembly, which can be miniaturized in response to the trend of miniaturization and light weight of a mobile communication terminal.

Still another object of the present invention is to provide a lens assembly for a mobile communication terminal, which is completely sealed to prevent liquid from penetrating into the lens assembly and is capable of removing particle-shaped foreign substances generated inside the camera module through liquid cleaning, the lens assembly including the lens assembly. To provide a camera module and a method for manufacturing a lens assembly.

Other objects and advantages of the present invention will become more apparent from the following detailed description of the invention.

According to the present invention having the above object, a lens assembly constituting a camera module mounted on a mobile communication terminal, comprising: a lens unit including a lens for photographing an object; And a lens barrel for accommodating the lens unit, wherein a lens having a maximum diameter among the lenses is disposed at a lower end of the lens barrel such that an outer circumferential surface of the lens having the maximum diameter is exposed to the outside of the lens barrel. It provides a lens assembly characterized in.

In this case, preferably, a sealing means is interposed between the upper peripheral portion of the lens having the maximum diameter and the lower peripheral portion of the barrel, the lens having the maximum diameter is coupled to the lower end of the barrel, and the sealing means has an adhesive force. Characterized in that there is a sealing material.

In addition, according to another embodiment, the second sealing means is formed by a groove formed in the inner circumference of the lens barrel adjacent to the outer side of the first lens disposed closest to the subject of the lens.

In addition, the present invention and the lens assembly described above; A housing in which the lens assembly is received; And an image sensor assembled to a lower end of the housing, the image sensor having an imaging area for receiving light passing through the lens assembly.

Preferably, the carrier is fastened to the outer periphery of the lens barrel of the lens assembly; The actuator may further include an actuator disposed at an outer periphery of the carrier to drive the carrier and the lens assembly in an optical axis direction. The actuator may be configured to interact with the lens by a magnetic field generated from a magnet and a driving coil to which power is applied. It may include a voice-coil motor for driving the actuator in the optical axis direction or a piezo actuator for driving the lens actuator in the optical axis direction by deformation of the piezoelectric body when power is applied.

In addition, the present invention provides a method for manufacturing a lens assembly constituting a camera module mounted on a mobile communication device, comprising the steps of: sequentially stacking a lens unit including a lens for imaging the subject in the assembly jig; Integrally coupling the lens units stacked on the assembly jig; Separating the integrally coupled lens unit from the assembly jig; And inserting an integrally coupled lens unit separated from the assembly jig into the lens barrel, wherein a lens having the largest diameter among the lenses constituting the lens unit is disposed at a lower end of the lens barrel to have the maximum diameter. And inserting the lens unit into the lens barrel such that the outer circumferential surface of the lens is exposed to the outside of the lens barrel.

In this case, the step of coupling the lens unit integrally, may include applying an adhesive to the outer peripheral surface of the lens unit exposed through the open side of the assembly jig.

Preferably, after the step of inserting the lens unit into the lens barrel, it may further comprise a step of sealing with the sealing means between the lower end of the lens barrel and the upper end of the lens having the maximum diameter, particularly preferred Preferably, the sealing means is a waterproof adhesive or a sealing material.

In addition, before the step of inserting the lens unit into the lens barrel, it may further comprise the step of forming a second sealing means with a groove formed in the upper inner circumference of the lens barrel.

In the present invention, since the lens having the largest diameter is exposed to the outside of the lens barrel, the entire diameter of the lens assembly can be reduced to the outer diameter of the lens having the largest diameter. Therefore, the overall size of the lens assembly can be reduced as compared with the conventional one, and thus the trend of miniaturization and light weight can be met.

In addition, since it is possible to include a lens having the same lens barrel size and an effective angle of view increased compared with the conventional art, it is possible to provide more light-images with an image sensor having an 8 million or more pixel-class image pickup device currently on the market. Because of this, high quality image reproduction is possible.

In addition, in the present invention, since the lens assembly is completely sealed to the outside, liquid cleaning such as water may be used during the assembly of the lens assembly and the camera module, in particular, to remove foreign particles in the form of particles formed in the image pickup area of the camera module. In addition, the cleaning liquid does not penetrate into the lens inner region even by liquid cleaning, thereby preventing product defects.

Accordingly, due to the formation of particles, it is possible to prevent an error in the image capturing process and to stabilize the focusing on the subject, and to realize a high quality image by avoiding the deterioration of the image quality during the capturing of the subject. .

As a result, a manufacturer of a lens assembly can supply a lens assembly manufactured according to the present invention, thereby manufacturing a camera module employing a miniaturized and high-end image sensor. In addition, the camera module manufacturer can use a method called liquid cleaning to remove particles such as foreign matter that may remain in the image capturing area of the camera module having the lens assembly of the present invention, so that the image capturing by the camera module finally manufactured In this case, it is possible to prevent a problem of poor image quality or poor focus due to particles remaining in the image capturing area.

1 is a schematic cross-sectional view of a lens assembly constituting a camera module mounted in a mobile communication terminal of the prior art.

2 is an exploded perspective view illustrating a process of assembling the lens unit constituting the lens assembly of the prior art into the lens barrel.

3 is a perspective view illustrating a state in which a lens assembly constituting a camera module mounted on a mobile communication terminal according to the present invention is assembled;

4A and 4B are views taken along the line IV-IV of FIG. 3 according to the first embodiment of the present invention. FIG. 4A is a sectional view and FIG. 4B is a sectional perspective view.

5 is a cross-sectional view of the lens assembly according to the second embodiment of the present invention.

6A to 6F are perspective views schematically illustrating an assembly state of a lens assembly according to a process of manufacturing a lens assembly according to the present invention.

FIG. 7 is a cross-sectional view schematically illustrating a camera module mounted on a mobile communication terminal, including a lens assembly according to a first embodiment of the present invention. As an example, a particle inside a camera module including an actuator of a VCM method. This is a cross-sectional view showing the generated state.

8 is a cross-sectional view illustrating a state in which liquid cleaning is possible in a camera module having a lens assembly according to a first exemplary embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating a state in which liquid cleaning is possible at a top and a bottom of a camera module having a lens assembly according to a second exemplary embodiment of the present invention.

The present inventor has studied the method for solving the above-mentioned problems of the prior art, and thus can be miniaturized even in a camera module employing an image sensor with an image sensor of 8 million pixels or more capable of high-definition image quality. In addition, a lens assembly for a mobile communication terminal and a camera module including such a lens assembly and a lens module capable of high-quality image reproduction, and in particular, liquid cleaning to remove foreign substances as particles formed in an image pickup area, are provided. A method of preparation has been proposed.

For convenience of description, in the present specification, terms such as 'top' and 'top' refer to the subject side, and 'bottom' and 'bottom' refer to the imaging surface side of the image sensor or the substrate side on which the image sensor is mounted. it means. In addition, when the lens assembly is 'sealed' or 'sealed', it should be understood that liquid such as water cannot penetrate into the space between the lens and the lens constituting the lens unit constituting the lens assembly. Preferred embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a perspective view schematically illustrating a state in which a lens assembly constituting a camera module mounted and mounted on a mobile communication terminal is assembled according to an embodiment of the present invention, and FIGS. 4A and 4B are a first embodiment of the present invention. 3 is a cross-sectional view taken along line IV-IV of FIG. 3, and FIG. 4A is a cross-sectional view and FIG. 4B is a cross-sectional perspective view. As shown, the lens assembly 100 according to the present invention can accommodate the lens unit 110 (see FIG. 6D) including the plurality of lenses L1, L2, L3, and L4, and the lens unit 110. It includes a substantially cylindrical lens barrel 120 so as to be hollow. The lens assembly 100 is disposed at the center of the camera module 300 (see FIGS. 7 to 9) to define an image capturing area for the subject.

The lens unit 110 includes a lens for adjusting the focus on the subject, and the lenses L1 to L4 may be made of optical glass or plastic material. Typically, the lens unit 110 is generally composed of a plurality of lenses in combination with an aspherical convex lens and a concave lens having a suitable and various curvature for collecting or dispersing light. Each lens is manufactured to have a predetermined curvature through, for example, injection molding, and is coupled with the spacers 132, 134, and 136 interposed therebetween, and is integrated into the lens barrel 120 as an integrated lens unit 110. Are accepted.

In this case, the diameter of the lens at the position closest to the side of the subject is smallest according to the optical element, and the diameter of the lens gradually increases toward the image plane. In the drawing, the lens unit 110 including four lenses L1 to L4 whose diameters gradually increase from the image side toward the image side toward the image side is shown as an example only. Rather, one of ordinary skill in the art will be able to arbitrarily adjust the number of lenses constituting the lens unit 100, the curvature or the diameter of each lens, etc. as necessary. For example, the number of lenses constituting the lens unit 110 may be at least one, and generally includes two to six lenses, but the present invention is not limited thereto. In particular, in the lens assembly 100 according to the present invention, the fourth lens L4 having the largest diameter is not accommodated in the lens barrel 120 to increase the effective angle of view.

On the other hand, by supporting each lens constituting the lens unit 110 to prevent it from tilting, the lens is assembled and arranged stably, while adjusting the distance between each lens, while shielding the transmitted light or if the light is emitted One or more spacers 132, 134, and 136 may be provided at an outer portion between the plurality of lenses L1 to L4 in order to prevent the reflection. These spacers may be made of a transparent material or an opaque material, for example, the first spacer 132 having a hollow area between the bottom of the outer edge of the first lens L1 and the top of the outer edge of the second lens L2. Is disposed, and a second spacer 134 having a hollow area is interposed between the lower edge of the outer edge of the second lens L2 and the upper edge of the outer edge of the third lens L3. In addition, a third spacer having a relatively large width and a hollow area between the lower end of the outer portion of the third lens L3 and the upper end of the outer portion of the fourth lens L4 so as to stably support the third lens L3 ( 136 is formed.

As described above, since the number or size of the lenses constituting the lens unit 110 may be changed as necessary, the number or size of these spacers disposed between the lenses may also be changed according to the number of lenses. to be. In addition, although not shown separately, a light shielding plate having a shape covering the upper end of the first lens L1 may be formed on the upper inner circumferential surface of the lens barrel 120 so that the light transmitting region of the lens unit 110 may be non- It may be configured to distinguish the transmission region.

On the other hand, the upper end of the lens barrel 120 of the hollow cylindrical body which is aligned in the optical axis direction, and accommodates a plurality of lenses (L1 to L4) constituting the lens unit 100 integrally coupled in advance as described below A hollow portion 122 is formed as a lens inlet for transmitting, and a lower portion thereof forms a hollow portion 123 (see FIG. 6D) that is much larger than the upper portion so that the lens unit 110 formed as a single body can be fitted in advance. Doing. Since the lens barrel 120 accommodates the lens unit 110 therein, the inner circumferential surface 124 of the lens barrel 120 is configured to correspond to the outer diameters of the lenses L1 to L3 accommodated therein. As shown in the drawing, the inner circumferential surface 124 of the lens barrel 120 is formed to have a step shape according to the diameters and curvatures of the lenses L1 to L3 to accommodate the lens unit 110 as an accommodation space therein. can do. A thread 126 is formed on the outer circumferential surface of the lens barrel 120, so that the lens barrel 120 accommodating the lens unit 110 is formed on the inner circumference of the carrier 310 constituting the camera module (see FIG. 6). Can be combined with the corresponding thread.

In this case, the lens unit 110 and the lens barrel 120 for accommodating the lens unit may be manufactured by injection molding using materials made of glass or plastic, which are well known to those skilled in the art. Can be. For example, the material of the first lens L1 is a cyclo olefin polymer (COP), a Zeonex E48R optical plastic (Nippon Zenon Co., Ltd.), and the material of the second lens (L2) is a polycarbonate having a high refractive index. Planetary SP1516 optical plastic (Deijin Kasei Co., Ltd.), a third resin (L3) and a fourth lens (L4), which are resins, may be selected from APEL optical plastic (Mitsui Chemical Co., Ltd.), a cyclic olefin polymer. Can be. In addition, as the material of the first spacer 132 and the second spacer 134 may be used a film plastic of Japan KIMOTO Co., Ltd., the lead-free brass (lead-free brass) as the material of the third spacer 136 ) Can be adopted. In addition, the lens barrel 120 may be integrally injection-molded using heavy polycarbonate (PC + GF30%) having excellent corrosion resistance.

However, unlike the conventional lens assembly, at least one of the lenses constituting the lens unit 110 in the center of the lens assembly 100 of the present invention is not housed inside the lens barrel 120 and the outside of the lens barrel 120. Exposed to In this case, the fourth lens L4, which is a lens having a maximum diameter among the plurality of lenses, is preferably arranged to be coupled to and connected to the lower end of the lens barrel 120, so that the outer circumferential surface of the fourth lens L4 is the lens barrel. It is exposed outside of 120.

Accordingly, the conventional lens assembly 1 has a diameter D plus the maximum diameter R ₁ of the lens plus the width W of the lens barrel (see FIG. 1), whereas the lens assembly 100 according to the present invention is provided. ) Has substantially the same size as the maximum lens diameter (R ₂ ). That is, the lens assembly 100 according to the present invention may reduce its size as much as the width W of the lens barrel, as compared with the diameter D of the conventional lens assembly. As such, if the diameter of the lens assembly 100 can be reduced, the size of the entire camera module 300 in which the lens assembly 100 is disposed in the center can also be reduced. Can be responded to.

In addition, it is necessary to adopt a lens having a large effective field of view, that is, a large area lens in order to realize a high quality image. However, in order to implement a desired driving force in the conventional camera module for a mobile communication terminal, the lens assembly 1 should have a diameter D plus the width W of the lens barrel to the maximum diameter R ₁ of the lens. Since the diameter D of the lens assembly can no longer be increased, the diameter R _{1 of the} lens having the maximum effective angle of view in the conventional lens assembly 1 cannot also be increased. As described above, in the case of the conventional lens assembly, since the lens having an increased effective angle of view cannot be adopted, even if an image sensor of 8 million pixels or more is adopted, high quality image is virtually impossible.

However, the lens assembly 100 according to the present invention has a size substantially corresponding to the maximum diameter R ₂ of the lens. Therefore, if the diameter of the lens assembly 100 of the present invention is set equal to the diameter D of the conventional lens assembly 1, the size of the lens having the maximum effective angle of view, that is, the maximum diameter (R ₂ ) of the lens is conventional Can be set equal to the diameter (D) of the lens assembly (1). In other words, even if the diameter D of the entire lens assembly is set equal, the maximum diameter R ₁ of the lens in the conventional lens assembly 1 is equal to the width W of the lens barrel at the diameter D of this lens assembly. There is a limit to the effective angle of view of the lens because it is the size except. However, since the maximum diameter R ₂ of the lens in the lens assembly 100 of the present invention is substantially the same as the diameter D of the entire lens assembly (ie, in this case the maximum diameter R ₂ of the lens of the present invention is Larger than the maximum diameter (R ₁ ) of the conventional lens, it is possible to increase the effective field of view. While the lens having an increased effective angle of view can be adopted, the size of the actuator does not decrease because the overall size of the lens barrel does not increase. Therefore, even if the image sensor of 8 million pixels or more is adopted, it is possible not only to realize the desired driving force, but also to realize high quality images.

In addition, in the lens assembly 100 of the present invention, a sealing is provided between the upper peripheral portion of the lower end of the third spacer 136, that is, the upper edge of the periphery, which is the outer edge of the fourth lens L4 having the largest diameter, and the lower end of the lens barrel 120. The means 150 is interposed to completely seal the inside of the lens unit 110 from the outside. In particular, according to the present invention, since the fourth lens L4 is exposed to the outside of the lens barrel 120, and preferably the fourth lens L4 is disposed below the lens barrel 120, the lens assembly In the state where the 100 is finally assembled, it is very easy to form the sealing means between the upper end of the periphery of the fourth lens L4 and the lower end of the lens barrel 120.

Sealing means 150 that can be used in accordance with the present invention include a separate member such as a packing member if it can be interposed with a gap between the periphery of the fourth lens L4, ie the top of the outer periphery and the bottom of the lens barrel 120. Can be used. However, in terms of minimizing parts, simplifying the assembly and manufacturing process, a waterproof adhesive and / or an adhesive and waterproof sealing material or a waterproofing liquid may be used.

 In this case, as an adhesive that may be used, a heat curable adhesive, a photocurable adhesive, or the like may be considered as any adhesive that can penetrate into a gap between fine electronic components. Especially preferably, it is a photocurable adhesive agent which does not contain the organic solvent which may adversely affect between fine electronic components. Examples of the photocurable adhesives include ultraviolet (UV) curable adhesives cured by ultraviolet rays, electron beam curable adhesives cured by artificial electron beams, and visible light curable adhesives curable by natural rays such as the sun.

UV curable adhesives include 1) polyester, polyether, urethane, epoxy and silicone reactive oligomers, 2) reactive diluents as crosslinkers of reactive oligomers, 3) photopolymerization initiators that absorb the energy of ultraviolet rays to initiate photopolymerization reactions, 4) As other components, it is composed of a photosensitizer, a colorant, a thickener, and a polymerization inhibitor, because the curing speed is high, the adhesive can be applied during the assembly process, and the coating effect of obtaining the sealing effect according to the present invention can be achieved. Particularly preferred.

On the other hand, components of the visible light curable adhesive include 1) acrylic (urethane acrylate, polyester acrylate, epoxy acrylate, polyfunctional (meth) acrylate) or polyene / polythiol-based (triaryl isocyanurate / Cured resin components such as diaryl maleate, etc.) 2) photopolymerization initiators such as camphor-quinone, alpha-naphthol, 3) sensitizers, 4) fillers (fillers), 5) other (elastomeric, silane coupling agents) Although it consists of etc., since it is favorable compared with a UV curable adhesive from the viewpoint of safety, light transmittance, or the diversity of the material to be deposited, it can be used instead of a UV curable adhesive.

As the sealing material that can be used, a silicone-based sealing material, a polyurethane-based sealing material and the like having good adhesive strength can be used in particular, and if necessary, it can be used in combination with the adhesive described above. In addition, in addition to the above-described adhesive and / or sealing material components or separately from the above-described adhesive and / or sealing material, a waterproofing solution such as acrylic or urethane may be used as the sealing means 150, and the sealing means ( 150 may be considered a spray method.

On the other hand, according to the first embodiment of the present invention described above, in particular, the liquid cleaning is shown in the form toward the lower end of the lens assembly 100, it can be considered a form in which the liquid can be cleaned also toward the top. 5 is a schematic cross-sectional view of the lens assembly 100 according to the second embodiment of the present invention. As shown, according to the second embodiment, a groove is formed in the upper end of the inner circumferential surface of the lens barrel 120 in contact with the outer portion of the first lens L1 positioned closest to the subject from among the lenses accommodated in the lens barrel 120. 125 is formed, and the second sealing means 160 is formed in the groove 125. Preferably, the second sealing means 160 is suitable for the groove 125 formed on the inner circumferential surface of the upper end of the lens barrel 120 by using the same waterproof adhesive and / or adhesive sealing material as the first sealing means 150. Can be applied.

Subsequently, a process of manufacturing the lens assembly 100 according to the present invention will be described with reference to FIGS. 6A to 6F, which schematically show a coupling relationship of components according to the process. As shown in FIG. 6A, the lens unit 110 including the plurality of lenses L1 to L4 and the spacers 132, 134, and 136 is stacked in the assembly jig 200. According to the present invention, the assembly jig 100 for sequentially stacking the lens unit 110 according to the stacking order of the final lens assembly 100 preferably has a hexahedron or cylindrical shape, and as shown, the bottom surface 202. And at least a portion of the side 204 is open. In addition, the inner circumferential surface 210 of the assembly jig 200 may include a plurality of lenses L1 to L4 and spacers 132 and 134 constituting the lens unit 110 so that the lens unit 110 may be sequentially stacked therein. , 136, and has a shape in which a stepped step is formed like the inner circumferential surface 124 of the lens barrel 120. The assembly jig 200 may be made of, for example, a plastic material having a high softening point, preferably a thermosetting plastic material or a metal material, and may be integrally formed through injection molding.

Through the open bottom surface 202 of the assembling jig 200, the plurality of lenses L1 to L4 and the spacers 132, 134, and 136 constituting the lens unit are sequentially arranged in an appropriate order. The stacked state is shown in FIG. 6B. Subsequently, a process of integrally combining the lens units including the plurality of lenses L1 to L4 and the spacers 132, 134, and 136 sequentially stacked on the assembly jig 200 is performed. Preferably, as shown in FIG. 6C, a method of coating a suitable bonding agent on the outer circumferential surface of these lens units may be considered by integrally coupling the lens units stacked in the assembly jig 200. In this case, as a bonding agent, a bonding agent used in the process of assembling the lens unit in the conventional lens assembly, for example, an epoxy bonding agent may be used. In addition, as an alternative method for integrally forming the lens unit, for example, by heating above the curing temperature of the polymer plastic, which is a material of the lens and the spacer, a method of bonding the sequentially stacked lenses and the spacer may be considered. will be.

In the above-described method, when a plurality of lenses and spacers are integrally coupled to each other, the lens unit 110 integrally coupled from the assembly jig 200 is separated through the open bottom 202 of the assembly jig 200. 6D, the integrated lens unit 110 is inserted into the lens barrel 120 through the hollow part 123 at the bottom of the lens barrel 120.

In particular, according to the present invention, since the fourth lens L4 having the largest diameter is not accommodated in the lens barrel 120, as shown in FIG. 6E, the fourth lens L4 has a lower end of the lens barrel 120. The outer circumferential surface of the fourth lens L4 is exposed to the outside of the lens barrel 120. At this time, if the case according to the second embodiment, the groove formed in the upper end of the inner peripheral surface of the lens barrel 120 corresponding to the outer side of the first lens (L1) disposed closest to the subject side of the integrally formed lens unit 110 ( 125, see FIG. 5), the second sealing means 160 may be applied in advance. Accordingly, when the lens unit 110 is accommodated in the lens barrel 120, the upper surface of the outer surface of the first lens L1, which forms the upper end of the lens unit 110, is formed at the top of the inner circumferential surface of the lens barrel 120. ), And the second sealing means 160 formed in the groove 125 has a gap between the inner circumferential surface of the lens barrel 120 and the upper surface of the outer portion of the first lens L1 and / or the outside thereof. It can be filled.

Subsequently, as shown in FIG. 6F, the sealing means 150 is treated between the upper end of the periphery of the fourth lens L4 and the lower end of the lens barrel 120 to completely seal the inside of the lens unit with the outside. If necessary, an additional bonding process is performed on the outer circumferential surface of the lens unit 110 so that the lens unit 110 constituting the lens assembly 100 sealed by the sealing means 150 can be stably assembled along the optical axis. Could be.

Subsequently, a camera module for a mobile communication terminal having a lens assembly 100 according to the present invention will be described with reference to FIGS. 7 and 8, which are cross-sectional views thereof. The camera module 300 according to the present invention includes a lens assembly 100 having an image capturing region through a photo-image of a subject in the center thereof, and an outer side of the lens barrel 120 forming an outline of the lens assembly 100. A substantially cylindrical carrier 310 which is fastened through thread coupling, etc., an actuator 320 for driving the carrier 310 and the lens assembly 100 accommodated therein in the optical axis direction, and in particular, the carrier 310. It includes a housing 340 that supports the lower end and extends to the outside of the driving actuator 320 to form an outline of the camera module 300. In addition, the image sensor 510 disposed on the substrate 350 so as to convert the optical image passing through the lens assembly 100 into an electrical signal, and the light-image in the state of blocking the light of a specific wavelength A filter 354 may be further provided for sending to the sensor 352.

The inner circumferential surface of the carrier 310 having a hollow cylindrical shape to accommodate the lens assembly 100 has a thread corresponding to the thread 126 formed on the outer circumference of the lens barrel 120. In addition, the outer circumference of the lower end of the carrier 310 forms a support portion 312 protruding outward to some extent to support the driving coil 326 constituting the actuator 300, whereby the driving coil 326 of the carrier 310 is formed. It can be stably arranged along the outer periphery.

In the drawing, although the actuator 310 is shown along the outer periphery of the carrier 310 coupled to the outer circumferential surface of the lens barrel 120 to perform the auto focus function on the subject, the actuator 310 does not have a focus adjustment function. Is not included in the camera module 300. In this case, a screw thread corresponding to a screw thread formed on the outer peripheral surface 126 of the lens barrel 120 is formed on the inner peripheral surface of the housing 340 without separately providing the carrier 310 toward the outer peripheral side of the lens barrel 120. The housing 320 may be directly coupled to the outer circumference of the barrel 120. In other words, as a member for accommodating the lens assembly 100, the carrier 310 coupled to the outside of the lens assembly 100 and the housing 340 surrounding the outside while supporting the lower end of the carrier 310 are separately shown in the drawing. However, in order to directly accommodate the lens assembly 100, a housing thread 340 formed on an inner circumferential surface of the thread 126 corresponding to the thread 126 formed on the outer periphery of the lens barrel 120 may be integrally formed.

In general, the carrier 310 or the housing 340 may be integrally manufactured by a press molding process using an insulating resin, for example, a plastic material of an insulating resin such as polycarbonate containing glass. At this time, the housing 340 is disposed in the form of supporting the lower end of the carrier 310 for receiving the lens assembly 100, the housing 340 having a hollow enough to surround the lower end of the carrier 310 The lower center forms an image capturing area A, and is implemented to transmit an optical image of a subject to a filter 354 or an image sensor 352 in which an image forming surface is formed.

On the other hand, to adjust the distance between the lens (L1 to L4) and the image sensor 352 to adjust the focus on the subject, the carrier 310 and the lens assembly 100 accommodated inside the carrier 310 optical axis An actuator 320 moving in the direction may be disposed outside the carrier 310. In the drawings, an actuator 320 of a voice coil motor (VCM) type is illustrated. Specifically, the actuator 320 of the VCM method for controlling the auto-focusing (AF) process for the subject includes a magnet 322 for generating a magnetic field, and a magnet for controlling the flow of the magnetic field generated from the magnet. A yoke 324 disposed around the periphery 322 and a drive coil 326 that receives a predetermined electric power from the outer power source.

The magnet 322 may use, for example, a neodymium-based permanent magnet, and is substantially ring-shaped with a hollow portion so as to be spaced apart from the top outer circumferential surface of the carrier 310. On the other hand, for example, a substantially hollow cylindrical yoke 324 made of a conductive material such as iron, cold rolled steel or nickel having excellent magnetic permeability is formed to surround the upper and inner circumferential surfaces of the magnet 322. . In order to efficiently control the flow of the magnetic field generated from the magnet 322, that is, the magnetic flux, the yoke 322 is disposed to have a cross-section having an approximately "A" shape. In addition, the driving coil 326 is electrically connected to an external power source to interact with the magnetic field generated by the magnet 322 to generate the Lorentz force, that is, the driving force due to the electromagnetic force. It is arrange | positioned in the form seated in the support part 312. Accordingly, the driving coil 326 is disposed in the form of a winding along the outer periphery of the carrier 310, and the position thereof may be changed in the optical axis direction together with the carrier 310 and the lens assembly 100 accommodated therein. It is configured to.

In addition, the upper spring 332 and the lower spring 334 are formed to provide a restoring force as the lens assembly 100 moves by the driving force of the actuator 320 and to provide a feeding path to the driving coil 326. do. At this time, the top spring 332 is disposed to the top of the carrier 310 and the yoke 324, the bottom spring 334 is between the outer bottom of the carrier 310 and the top protruding inward from the lower inner peripheral surface of the housing 340 Is placed on. The upper spring 332 and the lower spring 334 support the actuator 320 and provide a repulsive force to the driving force to prevent the lens assembly 100 and the carrier 310 from moving rapidly in the optical axis direction during the focusing process. do.

On the other hand, the image sensor 352 is disposed adjacent to the image capturing region A, which is a hollow region of the lower inner circumference of the housing 310. The image sensor 352 is preferably formed on an image forming surface of the lens, and is typically mounted to be electrically connected to the substrate 350 and accommodated in the lower end of the housing 340. In the image sensor, an imaging surface for image forming a subject incident through the lens assembly constituting the camera module is provided to receive a light-image of the subject incident through the lens assembly 100, and receive the light. The converted photo-image is converted into an electrical signal. The converted photo-image is converted into an electrical signal and stored as digital data, and then displayed as an image through a display medium. To this end, the image sensor 352 typically includes a pixel region composed of a plurality of pixel arrays, a photoelectric converter and a plurality of electrodes. In this case, the pixel array accumulates electric charges in response to the light passing through the lens actuator 100, and the photoelectric conversion unit converts the electric charges accumulated in the pixel array as light receiving elements into usable electrical signals.

In general, a chip module is mounted on the substrate 350 around the image sensor 352 by using surface mount technology (SMT), and after the image sensor 352 is bonded with an epoxy bond, the image sensor 352 is formed. The plurality of electrodes are subjected to a 'wire bonding' process that is electrically connected to the electrodes of the substrate 350 using wire bonding equipment. As a method of electrically connecting the image sensor 352 to the substrate 350, other methods besides wire bonding may be adopted. As the image sensor 352, a well-known device such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) may be used. The image signal electrically converted through the image sensor 352 is transmitted to the controller (not shown) through the substrate 350 and digitally processed.

In addition, since the image sensor 352, which is an image pickup device, detects infrared wavelengths and the screen color tone tends to be red during imaging, the image sensor 352 forms an optical-image in a state in which light in the wavelength band is blocked. Preferably, an infrared cut filter (IR filter, IR cut-off filter) 354 is disposed between the lens L4 at the bottom and the image sensor 3520 at the lower inner circumferential surface of the housing 340.

The VCM driving module may adjust the focus of the subject. Specifically, the image sensor in a state in which the light-image of the subject passing through the lens assembly 100, in which the lenses L1 to L4 are aligned in the optical axis direction, is blocked through the filter 354, and the light of the ultraviolet wavelength range is blocked. When transferred to 352, the image sensor 352 converts the signal into an electrical signal and transmits it to a controller (not shown) in the camera module 100 connected through the substrate 350. When the image signal of the subject is blurry, the controller recognizes a focusing error and applies a predetermined current to the driving coil 326. Accordingly, when a magnetic field is generated in the driving coil 326, the control unit mutually interacts with the magnetic flux generated by the magnet 322. As a result, the Lorentz force is generated to move the carrier 310 and the lens assembly 100 accommodated therein in the optical axis direction to adjust the focusing.

In the present specification, as an example of the actuator, an electric field generated by applying power to the drive coil 326 and a magnetic field generated by the magnet 322 interact with each other to generate an electromagnetic force generated in a vertical direction, that is, a Lorentz force as a driving force. An actuator 300 of a voice coil motor (VCM) type that drives the lens assembly 100 and the lens aligned therein in the optical axis direction is illustrated. However, in addition to this, it is also possible to adopt an actuator using any other method well known to those skilled in the art, in accordance with a mechanical method such as a linear motor or a step motor, or by applying power. Various types of actuators, such as piezo actuators using piezoelectric elements, which perform deformation of the piezoelectric body and correspond to the deformation of the piezoelectric body, drive the lens assembly and the lens accommodated therein in the optical axis direction may be adopted. Such actuators are well known to those skilled in the art, and thus detailed descriptions thereof will be omitted.

On the other hand, during the process of assembling and fastening the lens assembly 100 and the camera module 300 described above, fine foreign matter is generated in the form of particles P due to friction between components. Particularly, in view of the widespread popularity of mobile communication terminals equipped with a camera module 300 to which an image sensor 352 of 8 million pixels or more is applied, the shape of particles P remaining in the image capturing area A is obtained. It is necessary to remove foreign substances. That is, even if very fine particles P are formed in the image capturing area A, the image sensor 352, in which one pixel size is gradually decreasing, may not only cause a large error in image conversion of the subject, An error in focusing may cause a problem of poor image quality due to the inability to sharpen an image of a subject. However, it is inefficient for the inspector to remove the particles P one by one, and since there is a risk of component damage, it is not possible to completely remove the particles P remaining in the image pickup area A, even through air cleaning. In particular, in the prior art, it is impossible to clean the liquid because a problem such as water penetrating into the lens occurs and this causes a defect of the product.

However, according to the present invention, the lens assembly 100 is disposed close to the image capturing region A, and the upper end of the peripheral portion of the fourth lens L4 exposed to the outside of the lens barrel 120 and the lens barrel 120. The inside of the lens assembly 100 was completely sealed from its outer region by treating with the sealing means 150 between the lower ends of the) and sealing the gap between the components constituting the lens assembly 100. Accordingly, according to the present invention, since the lower end of the lens assembly 100, particularly the lens assembly 100 is completely sealed from the outside, liquid cannot penetrate into the area between the lens and the lens inside the lens assembly 100. . Accordingly, as shown, even when the actuator 320 is fastened and assembled to the outside of the lens assembly 100, particles such as foreign matters that may occur at the bottom of the lens assembly 100 using a liquid such as water ( P) can be removed.

As a result, according to the present invention, liquid cleaning is possible in order to remove particles remaining in the camera module 300 adopted in the lens assembly 100 and the mobile communication device using the lens assembly 100 as a constituent member. Particularly, the particles P remaining in the image capturing area A can be completely removed through the liquid cleaning, so that a focusing error due to the particles P can be prevented even when the camera module 300 is driven. The problem of deterioration of image quality can be solved.

In addition, referring to FIG. 9, which illustrates a camera module 300 employing a lens assembly (see FIG. 5) according to a second embodiment of the present invention, as well as the lower end of the lens assembly 100 in which an image capturing region is formed. In addition, since the lens assembly 100 of the upper portion close to the subject is also sealed from the outside, liquid cannot penetrate between the lenses inside the lens assembly 100. Therefore, in order to remove particles remaining near the upper end and the lower end of the camera module 300 employing the lens assembly 100 according to the second embodiment, liquid cleaning is possible at both the upper and lower ends.

In the above, the present invention has been described based on the preferred embodiments of the present invention, but the present invention is not limited thereto. Rather, one of ordinary skill in the art to which the present invention pertains can easily make various modifications and changes based on the above-described embodiments, and the fact that all such modifications and changes belong to the scope of the present invention. Will be evident in the claims.

Claims (15)

A lens assembly constituting a camera module mounted on a mobile communication terminal, A lens unit including a lens for photographing an object; And A lens barrel for accommodating the lens unit, The lens assembly of claim 1, wherein a lens having the largest diameter is disposed at a lower end of the lens barrel, and an outer circumferential surface of the lens having the maximum diameter is exposed to the outside of the lens barrel. 2. A lens assembly according to claim 1, wherein sealing means is interposed between the upper peripheral portion of the lens having the maximum diameter and the lower peripheral portion of the lens barrel. The lens assembly of claim 2, wherein the lens having the largest diameter is coupled to a lower end of the lens barrel, and the sealing means is an adhesive sealing material. The method of claim 2, And a second sealing means is formed by a groove formed in the inner circumference of the lens barrel adjacent to the outer side of the first lens disposed closest to the subject side among the lenses. A lens unit including a lens for capturing an object, and a lens barrel for accommodating the lens unit, wherein a lens having a maximum diameter among the lenses is disposed at a lower end of the lens barrel to have the maximum diameter A lens assembly whose outer circumferential surface thereof is exposed to the outside of the lens barrel; A housing in which the lens assembly is received; And And an image sensor assembled at a lower end of the housing and having an image forming area for receiving light passing through the lens assembly. The camera module according to claim 5, wherein a sealing means is interposed between the upper peripheral portion of the lens having the maximum diameter and the lower peripheral portion of the lens barrel. The camera module of claim 6, wherein the lens having the largest diameter is coupled to a lower end of the lens barrel, and the sealing means is an adhesive sealing material. The camera module according to claim 6, wherein the second sealing means is formed by a groove formed in the inner circumference of the lens barrel adjacent to the outer side of the first lens disposed closest to the subject among the lenses. The lens assembly of claim 5, further comprising: a carrier fastened to an outer periphery of the lens barrel of the lens assembly; And an actuator disposed at an outer periphery of the carrier to drive the carrier and the lens assembly in an optical axis direction. The piezoelectric element of claim 9, wherein the actuator is a voice coil motor or a piezoelectric element for driving the lens actuator in an optical axis direction by an interaction of a driving coil to which power is applied and a magnetic field generated in a magnet. Camera module comprising a piezo actuator for driving the lens actuator in the optical axis direction by the modification of. A method of manufacturing a lens assembly constituting a camera module mounted on a mobile communication terminal, Sequentially stacking lens units including a lens for photographing an object in an assembly jig; Integrally coupling the lens units stacked inside the assembly jig; Separating the integrally coupled lens unit from the assembly jig; And Inserting an integrally coupled lens unit separated from the assembly jig into the lens barrel, wherein a lens having the largest diameter among the lenses constituting the lens unit is disposed at a lower end of the lens barrel to have the maximum diameter; And inserting the lens unit into the lens barrel such that an outer circumferential surface of the lens barrel is exposed to the outside of the lens barrel. 12. The method of claim 11, wherein integrally coupling the lens unit comprises applying an adhesive to an outer circumferential surface of the lens unit exposed through the open side of the assembly jig. 12. The lens assembly of claim 11, further comprising after sealing the lens unit into the lens barrel, sealing between a lower end of the lens barrel and an upper end of the lens having the largest diameter with sealing means. How to manufacture. The method of claim 13, wherein the sealing means is a waterproof adhesive or a sealing material. 12. The method of claim 11, further comprising forming a second sealing means with grooves formed in the upper inner circumference of the lens barrel prior to inserting the lens unit into the lens barrel.

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