JP2009157279A - Lens unit, imaging apparatus, electronic equipment, and assembly method of lens unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the components of a lens unit from being adversely affected due to the reduction in size and thickness of an imaging apparatus in electronic equipment and to improve the assemblability of the imaging apparatus. <P>SOLUTION: The lens unit includes: a third lens 3 comprising an optical surface part 3c having optical characteristics and edges 3a and 3b surrounding the optical surface part 3c; a cylindrical barrel 4 storing the third lens 3; and a fixing member 5 fixing one end of the third lens 3 in an optical axis direction. The fixing member 5 includes a contact part 5a coming into contact with the edge 3b, avoiding the optical surface part 3c of the third lens 3 and a circumferential part 5b extended over a sidewall 4d of the barrel 4 from the contact part 5a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens unit, an imaging device, an electronic apparatus, and a method for assembling a lens unit.

  In recent years, along with the downsizing and thinning of electronic devices such as mobile phones and digital still cameras, imaging devices (for example, camera modules mounted on mobile phones) mounted on these electronic devices are also downsized and thinned. Is required.

  As an example of a camera module mounted on a mobile phone, in order to achieve a smaller and thinner camera module, the members that make up the camera module can be made smaller, or the thickness of the parts can be reduced. is doing. Therefore, the size and strength of the parts correspond to the limit.

  On the other hand, the optical performance required for the camera module is required to have higher precision, and in order to realize this, a highly accurate assembly technique is required.

  Furthermore, in order to maintain the optical performance, it is important to take measures against stray light that affects the optical performance. In particular, in a miniaturized / thinned camera module, incident light incident on the camera module is easily transmitted or reflected through an effective diameter region (optical surface portion) of the lens or a region other than the effective region (outer edge portion). As a result, stray light is generated in the camera module, which affects the optical performance as a ghost / flare. Therefore, in such a small and thin camera module, it is particularly necessary to take sufficient measures against stray light.

  As a countermeasure against stray light, first, an optical path of incident light that may become stray light is specified in advance by the optical design of the lens. And the light-shielding member which interrupts | blocks the optical path of incident light within a camera module is provided. Examples of such a configuration for countermeasures against stray light include a configuration in which a light shielding plate is provided between a plurality of lenses, or a configuration in which a light shielding member is provided around an effective diameter region of the lens.

  For example, Patent Document 1 discloses an imaging lens intended for forming an image on an imaging device, which includes an aperture stop, a first lens, a second lens, and a third lens, An imaging lens is disclosed in which the first lens, the second lens, and the third lens are disposed in order from the image side to the image side, and the aperture stop is disposed on the object side of the first lens. Yes.

  The imaging lens disclosed in Patent Document 1 has a configuration in which a first lens, a second lens, and a third lens are sequentially incorporated in a cylindrical lens frame (barrel). Has become easier.

Moreover, in the imaging lens disclosed in Patent Document 1, a member that determines the interval between the lenses is provided. And this member is comprised with the same member as a sheet | seat member and a lens frame, and is a light shielding member which cuts reflected light in black etc. In addition, in order to hold each lens inside the lens frame, a fixing member that holds a third lens arranged on the image side is provided. The fixing member is fixed or screwed to the lens frame.
JP 2007-156277 A (published June 21, 2007)

  However, the imaging lens disclosed in Patent Document 1 has a structure in which the lens frame and the fixing member are fixed or screwed together. Therefore, when the camera module is assembled, the thin lens frame is deformed or damaged. Problem arises. Hereinafter, this problem will be specifically described.

  For example, in a camera module mounted on a mobile phone, the size of components constituting the camera module becomes smaller as electronic devices become smaller and thinner. And the thickness of components is also reduced. For this reason, when individual parts are assembled using a conventional method to produce a camera module, the parts are damaged or deformed. As a result, the assembled camera module may not be able to obtain sufficient optical performance.

  In particular, in the lens unit, it is important to secure the optical performance of the camera module by assembling the lens in the barrel and providing a light shielding member for preventing stray light in the unit. However, the imaging lens disclosed in Patent Document 1 is assembled by press-fitting or screwing the fixing member into the barrel. Therefore, there is a possibility that the thinned barrel may be deformed or damaged during press-fitting or screwing. Further, such deformation / breakage may have an effect when the completed lens unit is assembled into a camera module. For example, when adjusting the interval between the image sensor and the lens unit, if the screw portion provided on the side surface of the barrel is deformed, it is impossible to perform adjustment with high accuracy.

  Furthermore, when the lens is inserted into the barrel and assembled, there is almost no flat portion (referred to as an edge) provided around the lens, resulting in poor assembling. In addition, problems such as touching the lens surface with a jig used at the time of lens insertion, or tilting the lens and inserting it into the barrel arise.

  For example, since the barrel and the fixing member are required to reduce the cost by mass production and shorten the manufacturing time, the barrel and the fixing member are often configured by using a generally molded resin material. As a result, manufacturing variation occurs and a uniform member cannot be obtained. Therefore, a tolerance is provided for each dimension of the member to determine an allowable variation. That is, in the method of press-fitting or screwing the fixing member into the barrel as in the invention of Patent Document 1, a gap or deformation of the barrel easily occurs due to variation in the member, and sufficient optical performance is obtained. There are things that can not be done.

  The present invention has been made in view of the above-described problems, and the object thereof is to prevent adverse effects on the components of the lens unit as the imaging apparatus in electronic devices is reduced in size and thickness, and the imaging apparatus is An object of the present invention is to realize a lens unit, an imaging device, an electronic apparatus, and a lens unit assembling method that can improve assembling without impairing optical performance.

  In order to solve the above-described problems, a lens unit of the present invention includes an optical surface portion having optical characteristics, a lens including an outer edge portion surrounding the optical surface portion, a cylindrical barrel that accommodates the lens, and the lens unit. A lens unit including a fixing member that fixes one end in the optical axis direction, wherein the fixing member avoids an optical surface portion of the lens and contacts an outer edge portion, and a side wall of the barrel from the corresponding contact portion. It has the outer peripheral part extended ranging over, It is characterized by the above-mentioned.

  According to the above configuration, even when the lens does not have a sufficient outer edge portion and light shielding by the member becomes difficult, or when the lens cannot be pressed by a jig for inserting the lens into the barrel, the fixing member Has an abutting portion that abuts on the outer edge portion of the lens, and a pressing area can be secured by pressing through the abutting portion. Therefore, according to the above configuration, it is easy to press the lens inserted into the barrel with the jig, and the size of the fixing member can be increased. Thereby, handling of a fixing member becomes easy.

  Further, according to the above configuration, since the fixing member has the outer peripheral portion extending from the corresponding contact portion to the side wall of the barrel, there is no interference between the outer peripheral portion and the side wall of the barrel, and the barrel is deformed. Can be prevented.

  Therefore, according to the above-described configuration, it is possible to avoid adversely affecting the components of the lens unit as the imaging device in the electronic apparatus is reduced in size and thickness, and to improve the assemblability without impairing the optical performance of the imaging device. A lens unit that can be provided can be provided.

  The outer peripheral portion of the fixing member is configured to extend from the contact portion to the side wall of the barrel. This outer peripheral portion can be brought into contact with the barrel side wall during or after pressing the fixing member via the contact portion. When the outer peripheral portion of the fixing member comes into contact with the barrel side wall, the outer peripheral portion makes contact with the barrel side wall perpendicularly, thereby suppressing the deformation of the barrel that occurs when the fixing member is pressed in the optical axis direction. is there.

  In the lens unit of the present invention, it is preferable that the fixing member has an outer periphery having the same size as the barrel.

  According to said structure, since the said fixing member has the outer periphery of the same magnitude | size as the said barrel, when adjusting a lens unit to an optical axis direction, the outer peripheral part of a fixing member does not influence. .

  In the lens unit of the present invention, it is preferable that the outer peripheral portion is separated from the side wall of the barrel in the optical axis direction.

  According to said structure, since the said outer peripheral part is spaced apart in the optical axis direction from the side wall of the said barrel, while being able to suppress the deformation | transformation of the barrel which arises when pressing a fixing member in an optical axis direction, it is required The member to be fixed can be easily provided according to the above. Therefore, according to the above configuration, the optical performance of the lens unit can be maintained.

  In the lens unit of the present invention, it is preferable that a light shielding member is provided between the fixing member and the outer edge portion of the lens.

  Thereby, the light shielding function can be imparted to the fixing member.

  In the lens unit of the present invention, the fixing member may have a light shielding function.

  In this case, compared to a configuration in which a light shielding member is provided between the fixing member and the outer edge portion of the lens, it is possible to reduce the number of members, the member cost, and the tact time.

  In the lens unit of the present invention, it is preferable that the fixing member is formed with an inclined portion that is inclined so as to become wider toward the other end opposite to the one end of the lens.

  According to the above configuration, the fixing member is formed with the inclined portion that is inclined so as to become wider toward the other end opposite to the one end of the lens, so that it passes through the lens group in the lens unit. Thus, the incident light beam and the fixing member do not interfere with each other. Therefore, a lens unit with good optical performance can be obtained without being affected by the fixing member.

  In the lens unit of the present invention, it is preferable that the abutment portion and the outer peripheral portion of the fixing member have different thicknesses in the optical axis direction.

  Since the fixing member needs to have a configuration that does not interfere with incident light, the thickness of the fixing member is limited. As a result, there is a possibility that the strength of the fixing member cannot be obtained sufficiently. According to the above configuration, the abutment portion and the outer peripheral portion of the fixing member have different thicknesses in the optical axis direction, so that the strength of the fixing member can be ensured.

  In the lens unit of the present invention, it is preferable that the fixing member has a fitting region that fits with the outer edge portion of the lens.

  Thereby, when positioning the fixing member, rough adjustment can be easily performed through the fitting region.

  In the lens unit of the present invention, it is preferable that the fixing member is formed integrally with the lens.

  Thereby, the number of parts can be further reduced and the manufacturing time can be shortened.

  In the lens unit of the present invention, the outer peripheral portion of the fixing member is a protruding portion that partially protrudes toward the side wall of the barrel, and the side wall of the barrel is recessed so as to surround the protruding portion. It is preferable that a recess is formed.

  According to said structure, the said outer peripheral part in a fixing member becomes the protrusion part in which the one part protruded to the side wall side of the said barrel, and it was dented so that the said side wall of the said barrel might surround the said protrusion part Since the recess is formed, the lens surface can be prevented from being damaged due to contact with a tray or the like during transportation of the lens unit.

  In the lens unit of the present invention, it is preferable that a groove is formed on the outer peripheral portion of the fixing member.

  The groove portion becomes a clear application region of the adhesive when the side wall of the barrel and the fixing member are fixed with the adhesive. Thereby, in the assembly of the lens unit, the adhesive application time can be shortened and the adhesive curing time can also be shortened.

  The lens unit of the present invention is a lens unit for entering a light beam from an object and forming an image on an image sensor, and the lens includes a plurality of lenses that are in contact with each other in the optical axis direction. Among these, it is preferable that the area of the optical surface portion of the lens disposed on the image surface side is larger than the area of the optical surface portion of the lens disposed on the object side.

  According to the above configuration, among the plurality of lenses, the area of the optical surface portion of the lens disposed on the image plane side is larger than the area of the optical surface portion of the lens disposed on the object side. -It can be a thin lens unit.

  The lens unit of the present invention may be configured such that the contact portion of the fixing member is in contact with the outer edge portion of the lens disposed closest to the image plane among the plurality of lenses.

  The lens unit of the present invention may have a configuration in which the contact portion of the fixing member is in contact with the outer edge portion of the lens disposed closest to the object side among the plurality of lenses.

  In order to solve the above-described problems, an image pickup apparatus according to the present invention includes the lens unit described above and an image pickup element.

  Moreover, in order to solve the above-described problems, an electronic apparatus according to the present invention includes the above-described imaging device.

  As a result, there is no adverse effect on the components of the lens unit with the downsizing / thinning of the image pickup apparatus in the electronic device, and the image pickup apparatus and the electronic that can improve the assemblability without impairing the optical performance of the image pickup apparatus Equipment can be provided.

  Further, in order to solve the above problems, the lens unit assembling method of the present invention includes an insertion step of inserting a lens into a cylindrical barrel, and a fixing member so as to contact one end of the lens in the optical axis direction. And a first pressing step of pressing the fixing member in the optical axis direction, and a fixing step of fixing the barrel and the fixing member.

  According to the above configuration, the fixing member is arranged so as to contact one end of the lens inserted in the cylindrical barrel in the optical axis direction, and the fixing member is pressed in the optical axis direction (first pressing step). Then, since the barrel and the fixing member are fixed (fixing step), the lens units can be assembled together. Therefore, the manufacturing time of the lens unit can be shortened.

  Further, in order to solve the above problems, the lens unit assembling method of the present invention includes a fitting step of fitting a lens to the fixing member, and an outer peripheral portion extending from the lens fitting portion to the outer periphery of the fixing member. It includes an application step of applying an adhesive, a second pressing step of covering the lens with a cylindrical barrel and pressing the barrel in the optical axis direction, and a fixing step of fixing the fixing member and the barrel. Yes.

  Thereby, when positioning the fixing member, rough adjustment can be easily performed via the fitting portion of the lens in the fixing member.

  In the lens unit assembling method of the present invention, the coating step may be performed after the second pressing step.

  In the lens unit of the present invention, as described above, the fixing member includes an abutting portion that abuts on an outer edge portion avoiding the optical surface portion of the lens, and an outer peripheral portion that extends from the corresponding portion to the side wall of the barrel. It is the structure which has.

  Moreover, the imaging device of this invention is the structure provided with the said lens unit and an image pick-up element as mentioned above. Further, as described above, the electronic apparatus of the present invention has a configuration including the imaging device.

  The lens unit assembling method of the present invention, as described above, includes an insertion step of inserting a lens into a cylindrical barrel, and a fixing member disposed so as to abut one end of the lens in the optical axis direction. It is the structure including the 1st press process which presses a fixing member to an optical axis direction, and the adhering process which adheres the said barrel and the said fixing member.

  As described above, the lens unit assembling method of the present invention includes a fitting step of fitting the lens to the fixing member, and a second pressing step of covering the lens with the cylindrical barrel and pressing the barrel in the optical axis direction. And a fixing step for fixing the fixing member and the barrel.

  Therefore, it is possible to prevent the lens unit parts from being adversely affected as the image pickup apparatus in the electronic apparatus is reduced in size and thickness, and to improve the assemblability without impairing the optical performance of the image pickup apparatus.

[Embodiment 1]
An embodiment of the present invention will be described with reference to FIGS. 1 to 5 as follows.

  The configuration of the imaging apparatus of the present embodiment (hereinafter referred to as the present imaging apparatus) will be described with reference to FIG. FIG. 1 is a cross-sectional view illustrating a schematic configuration of the imaging apparatus.

  Here, a camera module mounted on a mobile phone will be described as an example of the imaging apparatus. However, the imaging device may be an imaging device mounted on other electronic devices other than the mobile phone. In particular, a mobile phone is preferable as an electronic device applicable to the present invention. A mobile phone is an electronic device that is significantly reduced in size and thickness. For this reason, the demand for the reduction in size and thickness of the camera module mounted on the mobile phone is the highest.

  On the other hand, there is a limit to reducing the size of the solid-state imaging device. Therefore, when a mobile phone as an electronic device is reduced in size and thickness, light rays enter the camera module at a large incident angle. And in a camera module, reflection of incident light increases except for optical components such as lenses. As a result, the light emitted from the camera module enters the solid-state image sensor as stray light, and the stray light becomes a factor that affects optical performance such as ghost and flare. For this reason, when the mobile phone is reduced in size and thickness, it is important to sufficiently shield the light in the camera module. In particular, light shielding around the lens through which incident light passes is most important.

  As shown in FIG. 1, the camera module 100 includes a lens unit 10, a drive mechanism 11 that drives the lens unit 10, and a sensor 12. The sensor 12 has a solid-state image sensor (image sensor) 12a. Then, the lens unit 10 forms an incident light beam on the solid-state imaging device 12a. In the camera module 100, the drive mechanism 11 finely adjusts the position of the lens unit 10 with respect to the solid-state image sensor 12a, thereby controlling the image formation of the solid-state image sensor 12a.

  When it is necessary to form a high-pixel image on the solid-state imaging device 12a, the camera module is configured to include the drive mechanism 11. Further, the drive mechanism 11 may fix the lens unit 10 at an optimal position with respect to the sensor 12.

  Next, each member constituting the camera module 100 will be described more specifically.

[Sensor 12]
As the solid-state imaging device 12a provided in the sensor 12, a CCD or a CMOS is used according to the required number of pixels. The solid-state image sensor 12a is mounted on a substrate or the like. A transparent region made of glass is provided in a region that faces the solid-state imaging device 12a and through which light passes. The periphery of the translucent region is sealed with black resin or the like. The sensor 12 includes a solid-state imaging device 12a, a substrate on which the solid-state imaging device 12a is mounted, the light-transmitting region, and the resin sealed around the light-transmitting region.

  In addition, an IR cut filter or the like is formed on the glass surface in the translucent region as necessary.

[Lens unit 10]
The lens unit 10 is often composed of a plurality of lenses, and functions as an optical system that forms an incident light beam on the solid-state imaging device 12a.

  The size of the optical system and the solid-state imaging device 12a in the camera module is restricted by the size of an electronic device in which the camera module such as a mobile phone or a digital still camera is mounted. In addition, with respect to the solid-state imaging device 12a, the optical system (lens unit 10) has an optimized lens shape and arrangement so that optical performance is optimized by optical design.

  The lens unit 10 may be a single lens. The number of sheets increases as the performance increases, but the configuration of the lens, the barrel, and the member that blocks stray light is the same.

[Lens constituting the lens unit 10]
The plurality of lenses constituting the optical system (lens unit 10) are made of glass, plastic or the like. And this lens is processed into the shape of a lens by shaving or a mold using a mold. The shape of each lens is optimized by the optical design of the optical system when combined with a plurality of lenses. As the lens material, a glass material or a resin material having necessary transparency and refractive index is selected. This lens is formed as a spherical lens or an aspherical lens, and further, an edge is formed as necessary.

  Plastics are used as a material for this lens in response to demands for smaller, thinner and higher pixel camera modules. In many cases, a plastic lens having an aspheric shape formed by a mold is used as the lens. The plastic lens is suitable for forming a relatively small shape or a complex aspheric surface, and a large number of similar plastic lenses can be produced by molding using a mold. Therefore, by using a plastic lens as a lens constituting the lens unit, camera modules having the same optical performance can be mass-produced.

  Furthermore, the assembly adjustment of the lens unit 10 has become difficult due to the miniaturization of the camera module. In order to facilitate assembly and adjustment of the lens unit 10, an edge (outer edge portion) is provided around the optical surface portion (effective diameter region of the lens) having optical characteristics of each lens constituting the lens unit 10. Then, by setting the edge shape so that the edges of the individual lenses can be fitted to each other, it is not necessary to adjust the lens when the lens unit 10 is assembled. That is, by assembling the lenses through the edge fitting between the individual lenses, the assembly adjustment of the individual lenses becomes highly accurate. In this way, by providing the fitting portion on the lens and fixing the adjacent lenses using the edge fitting, it is possible to obtain a lens unit that suppresses the shift and tilt of the lens.

  Note that the edge here refers to a region that is provided around the effective diameter region of the lens and has a plane perpendicular to the optical axis. For example, the edge is used as a reference surface when fixing the lens to the lens holder 10 or when fitting the lenses. Moreover, when fixing lenses with an adhesive agent, it is utilized as an application | coating surface of this adhesive agent. In addition, the edge may have a configuration in which a fitting portion in which the lenses are fitted is provided as necessary.

  In the lens unit 10 of the present invention, in order to reduce the size and thickness of the lens unit 10, the edge is provided with a flat portion and a fitting portion between adjacent lenses. The lens unit 10 is configured such that adjacent lenses are in contact with each other. In the above configuration, it is desirable to use a lens produced by plastic molding as the lens. The lens obtained by molding measures the outer shape and eccentricity of the lens, and if necessary, feeds back to the mold used for molding and corrects it as necessary to achieve the required lens shape. I will do it.

  In addition, in order to prevent stray light caused by a part of incident light passing through the optical system of the lens unit 10 or light having passed around the effective diameter of the lens, an optical path of the incident light is provided in a spatial region between the lenses. It is good also as a structure which provided the light-shielding member which interrupts | blocks.

  In the case where a stop is provided in the optical system, any one of the light shielding members may function as a stop, or a configuration in which a stop function is provided to a part of the lens barrel may be employed. As a result of optical design of the optical system, it may be appropriately configured depending on the position of the stop.

  By optimizing the position of the aperture of the optical system so that a part of the lens barrel has the function of the aperture, there is no need to provide a new aperture, the light shielding member can be reduced, and the optical axis alignment between the aperture and the lens center can be achieved. However, it can be assembled with high accuracy without adjustment.

[Barrel of lens unit 10]
The lens unit 10 has a configuration in which an optical system having a plurality of lenses is inserted into a barrel and assembled and adjusted. The optical system having a plurality of lenses is appropriately fixed to the barrel with an adhesive or the like. Hereinafter, the barrel will be described.

  The barrel is made of a plastic material having a black color. Examples of the plastic material constituting the barrel include resins such as ABS, polycarbonate, and liquid crystal polymer. The barrel is formed by processing the plastic material described above, such as molding or cutting.

  The resin material used at this time can be appropriately selected according to the application of the camera module on which the barrel is mounted. For example, in the case of a barrel of a camera module mounted on a portable electronic device or the like, the camera module is required to be reduced in size and thickness. And with this request, it is necessary to reduce the thickness of the wall surface constituting the barrel. For this reason, it is desirable to use a resin material having relatively high rigidity as a resin material constituting the barrel so that the shape is not deformed or damaged by an impact at the time of dropping. Further, as a countermeasure against an impact at the time of dropping, by performing an impact analysis of the barrel, a location where deformation is likely to occur or a location where damage is likely to occur may be specified in advance. Then, by increasing the thickness of the specified part or adding a rib, the barrel can be processed into a shape that is resistant to deformation and breakage.

[Drive mechanism 11]
The drive mechanism 11 slides along the optical axis of the optical system (lens unit 10) of the camera module. As such a drive mechanism, for example, a stepping motor is used to slide the lens barrel in the optical axis direction along the cam or shaft axis (hereinafter referred to as a stepping motor method), and is generated by a magnet and a coil. A method of sliding the lens barrel in the direction of the optical axis by thrust generated by the electromagnetic induction phenomenon (hereinafter referred to as VCM method), or a method of sliding the lens barrel in the direction of the optical axis by frictional force generated by a piezoelectric element or the like (Hereinafter referred to as a friction drive system).

  The above-described method of the drive mechanism 11 can be appropriately selected according to the size of the camera module and the range in which the optical system is slid. For example, a VCM system is often used as a drive mechanism employed in a camera module having an autofocus function. The drive mechanism using the VCM method has the following configuration, for example. That is, as a configuration of the drive mechanism 11, a configuration in which a coil is disposed on the outer periphery of the barrel and the barrel is slid in the optical axis direction by a thrust generated in the optical axis direction due to an electromagnetic induction phenomenon.

  In the above description, the configuration in which the drive mechanism 11 is a VCM system has been described as an example. However, the drive mechanism 11 is not limited to this method, and the actuator may be configured using any of the drive mechanisms of a stepping motor method, a VCM method, and a friction drive method. For the drive mechanism 11, an optimal drive system may be selected from the downsizing / thinning of the camera module and the accompanying reduction in component size.

  In order to realize a thin and small camera module, a VCM method or a friction drive method is often adopted. In this case, since the thrust by electromagnetic force and the friction force by friction are not so large, it is desirable that the member to be driven be as light as possible. Therefore, it is possible to reduce the size of the lens unit (reduce the thickness of the barrel) or adopt a plastic material for the lens.

  The drive mechanism 11 is provided with a screw portion that is screwed with a screw portion provided in the lens unit 10. The lens unit 10 can be adjusted in the optical axis direction between the solid-state imaging device 12a and the lens unit 10 by being screwed into a screw portion provided with the drive mechanism 11.

  In particular, this position adjustment ultimately determines the optical performance of the camera module. Therefore, if the screwing with the screw portion of the drive mechanism 11 is deteriorated due to deformation of the barrel or the like, there arises a problem that the position adjustment of the lens unit 10 in the optical axis direction becomes insufficient. Further, there arises a problem that the lens unit 10 is tilted with respect to the solid-state image pickup device 12a (the lens unit 10 is arranged to be inclined with respect to the solid-state image pickup device 12a).

  The lens unit of the present invention can prevent barrel deformation. Therefore, when the camera module is assembled, it is possible to adjust the position of the lens unit 10 and the solid-state imaging device 12a in the optical axis direction with high accuracy. Hereinafter, the configuration of the lens unit 10 that is a feature of the present invention will be described in more detail.

  Here, the drive mechanism has been described. However, when high performance is not required, that is, when the autofocus function is not required, a structure in which a frame body for fixing the lens unit may be provided instead of the drive mechanism. Absent. For example, the frame may be formed by molding or cutting using the same material as that of the barrel, and provided with a screw portion that can be adjusted in position with the barrel. In this configuration, which requires only one or two lenses, further downsizing and thinning are required, and the configuration of the present invention becomes more effective.

[Configuration of Lens Unit 10]
FIG. 2 is a cross-sectional view showing a schematic configuration of the lens unit 10 of the present invention.

  As shown in FIG. 2, the lens unit 10 includes a first lens 1 as a plurality of lenses, a second lens 2, a third lens 3, a cylindrical barrel 4, and a third lens. 3 is provided with a fixing member 5 for fixing one end in the optical axis direction, and light shielding members 6 and 7.

  The first lens 1 and the second lens 2 are fixed so that their optical axes are at optimum positions (positions where eccentricity and tilt are reduced), and the second lens 2 and the second lens 2 are fixed. The third lens 3 is also fixed so that the optical axes thereof are at optimum positions (positions where eccentricity and tilt are reduced).

  The 1st lens 1, the 2nd lens 2, and the 3rd lens 3 are lens groups used as the optical element which has a specific effect | action by combining each. In the present embodiment, a lens unit 10 in which a light beam enters from the first lens 1 and is emitted from the third lens 3 through the second lens 2 will be described. That is, when the lens unit 10 is attached to the imaging device, the first lens 1, the second lens 2, and the third lens 3 are arranged in the order in which they are arranged on the object side that is the subject. In the following description, the side opposite to the object side is the image plane side.

  The first lens 1, the second lens 2, and the third lens 3 are respectively optical surface portions 1c, 2c, and 3c having optical characteristics, and an edge (outer edge portion) 1a that surrounds the optical surface portions 1c, 2c, and 3c. 2a * 2b and 3a * 3b.

  In the present embodiment, edges 1a and 2a (outer edge portions) provided in regions outside the optical surface portions of the first lens 1 and the second lens 2 are fitted to each other so that the first lens 1 and the first lens 1 The eccentricity and tilt adjustment between the two lenses 2 is performed. Similarly, the edges 2b and 3a provided in the regions outside the optical surface portions of the second lens 2 and the third lens 3 are fitted to each other so that the second lens 2 and the third lens 3 Eccentricity and tilt adjustment are performed. In addition, the adjustment between each lens may employ | adopt the method of adjusting while observing the resolution other than the fitting of edge 1a * 2a and edge 2b * 3a.

  The light shielding member 6 is inserted between the first lens 1 and the second lens 2 and is disposed at a position where unnecessary light generated by reflection on the surface of each lens is not incident on other lenses.

  The light shielding member 7 is disposed between the second lens 2 and the third lens 3, and is disposed at a position where unnecessary light is not incident on other lenses, similarly to the light shielding member 6.

  The first lens 1, the second lens 2, and the third lens 3 are accommodated in a cylindrical barrel 4. The barrel 4 is formed with a throttle portion 4c having a first opening 4a and a second opening 4b. The first opening 4a is smaller than the second opening 4b. The first opening 4a may also serve as a diaphragm. Here, the 2nd opening part 4b has shown the side (entrance side) in which the 1st lens 1, the 2nd lens 2, and the 3rd lens 3 are inserted.

  In other words, the barrel 4 has an inner diameter (an inner diameter of the inner wall portion forming the first opening 4 a) at one end (one end on the object side) in the optical axis direction smaller than the outer shape of the first lens 1. The inner diameter of the other end (one end on the image plane side) in the optical axis direction (the inner diameter of the inner wall portion forming the second opening 4 b) is the same as the outer shape of the third lens 3. The barrel 4 is arranged so that the inner wall surface covers the outer periphery of the first lens 1, the second lens 2, and the third lens 3.

  In addition, a screw portion 9 that is screwed with the lens barrel is provided on the outer periphery of the barrel 4, and by the rotation by the screw portion 9, it is possible to adjust the position of the solid-state imaging device and the lens unit 10 in the optical axis direction. Yes.

  The fixing member 5 includes an abutting portion 5 a that abuts on the edge 3 b disposed at one end of the third lens 3 in the optical axis direction, and an outer peripheral portion 5 b that extends from the abutting portion 5 a to the side wall 4 d of the barrel 4. Have. The outer peripheral portion 5b of the fixing member 5 is separated from the barrel 4 side wall 4d in the optical axis direction. In the lens unit 10, the adhesive 8 is injected into the gap between the outer peripheral portion 5b and the side wall 4d.

  Due to the downsizing and thinning of the lens unit, the thickness of the side wall of the barrel has been reduced, and when the fixing member is press-fitted or screwed into the barrel as in the prior art, the barrel is easily deformed. End up. Therefore, the optical performance of the lens unit is greatly affected.

  In the lens unit 10, a contact portion 5 a that contacts the edge 3 b of the third lens 3 is formed on the fixing member 5. Further, an outer peripheral portion 5b extending from the contact portion 5a to the side wall 4d of the barrel 4 (in the outer peripheral direction) is formed. Moreover, the outer peripheral part 5b is spaced apart from the side wall 4d of the barrel 4 in the optical axis direction. With this configuration, the outer peripheral portion 5 b of the fixing member 5 can be increased up to the thickness of the side wall 4 d without interfering with the barrel 4. Therefore, since the fixing member 5 and the barrel 4 are not in contact with each other, the barrel 4 is not deformed when the fixing member 5 is pressed, and the optical performance of the lens unit 10 can be maintained. Furthermore, since the fixing member 5 can be enlarged up to the thickness of the side wall 4d, the fixing member 5 can be easily handled when the lens unit 10 is assembled.

  In addition, as shown in FIG. 2, the outer periphery of the fixing member 5 is substantially the same size as the outer periphery of the barrel 4 or smaller than the outer periphery of the barrel if a sufficient surface can be secured to press the fixing member. It is preferable that That is, the outer peripheral portion 5 b is disposed so as to straddle the one end 4 e and the other end 4 f in the outer peripheral direction of the side wall 4 d of the barrel 4. Accordingly, when the lens unit 10 is adjusted in the optical axis direction by screw fitting, contact between the outer peripheral portion 5b of the fixing member 5 and the drive mechanism can be prevented.

  Further, the lens unit 10 has a configuration in which the end surface in the optical axis direction of the third lens 3 slightly protrudes from the end surface of the side wall 4 d of the barrel 4. Thereby, it is set as the structure which the side wall 4d of the barrel 4 and the fixing member 5 left | separated, ie, the structure which provided the clearance gap. As a result, the outer peripheral portion 5b of the fixing member 5 does not come into contact with the side wall 4d of the barrel 4, so that the barrel 4 is not deformed.

  More specifically, the outer diameter of the barrel 4 of the lens unit 10 is about φ5 mm. The thickness of the side wall 4d of the barrel 4 is about 0.5 mm. Therefore, the lens inserted into the barrel 4 does not have about φ4.5 mm including the edge. Further, each member in the lens unit 10 has a tolerance (variation) of at least about ± 0.01 mm. For this reason, the lens unit 10 is set to determine whether or not the lens and the side wall 4d of the barrel 4 are in contact with each other (a clearance is provided between the lens and the side wall 4d of the barrel 4). This is because such contact with the inner wall 4 d of the barrel 4 causes deformation of the barrel 4 and also leads to deformation of a screw portion provided on the outer periphery of the barrel 4.

  In the method of assembling the lens unit 10, the application amount of the adhesive 8 may be adjusted in consideration of the case where the barrel 4 and the fixing member 5 are in contact with each other. Further, the lens unit 10 may have a configuration in which the barrel 4 or the fixing member 5 is appropriately provided with a groove or the like through which the adhesive 8 escapes.

  Further, in FIG. 2, a gap is provided between the outer periphery of the lens group and the inner periphery of the barrel 4, but the side wall 4 d of the barrel 4 may be provided so as not to be deformed, and the lens group is attached to the barrel 4. A lightly press-fitted configuration (contacting) may be used. If the configuration is lightly press-fitted, the lens group and the barrel 4 are fixed, and it is not necessary to fix them with an adhesive or the like.

[Lens configuration]
The lens in the lens unit 10 shown in FIG. 2 includes three lenses that form an incident light beam on the solid-state imaging device. That is, the lens unit 10 is for entering a light beam from an object and forming an image on an image sensor. The first lens 1 serving as the object side lens is relatively small, and the third lens 3 serving as the image side lens has a relatively large lens configuration.

  The lens configuration of the lens unit 10 is not limited to the configuration shown in FIG. 2, and can be appropriately set from one to several so that the optical performance required by the optical design can be obtained. For example, in the case of a camera module mounted on a mobile phone and having a high performance of 3 million pixels or 5 million pixels that require an autofocus function, a configuration in which about 3 or 4 lenses are provided And often.

  At this time, the effective diameter (of the optical surface portion) of the lens on the object side is relatively small, and the effective diameter (of the optical surface portion) of the lens on the image surface side is often relatively large. Therefore, in the lens on the image plane side, there is a restriction on the edge formation around the optical surface portion, and a sufficient edge area cannot be secured. The reason is that when the edge is formed so as to secure a sufficient area, the outer shape of the lens on the image plane side becomes larger, and the outer shape of the barrel needs to be increased accordingly. This increases the size of the entire lens unit, which is not preferable for an imaging apparatus.

  Accordingly, the edge provided on the lens on the image plane side cannot be sufficiently secured, and it is difficult to secure a sufficient space for providing the light shielding member and the fixing member.

The influence on the optical performance (stray light) becomes more conspicuous against the physical constraints such as the size of the entire lens unit as described above. Therefore, it is necessary to take sufficient measures against the influence on the optical performance (stray light). In other words, as a result of reducing the size and thickness of the imaging device,
(1) The effective diameter region (optical surface portion) of the lens is arranged close to the edge (outer edge portion) and the barrel outer side surface; and
(2) The incident angle of the light beam with respect to the optical axis of the lens increases.
As a result, stray light is likely to be generated, and it is more important to take measures against this stray light.

  On the other hand, in order to reduce the size of the entire lens unit, it is necessary to reduce the thickness of a member such as a barrel. In the conventional method, due to deformation of the barrel or the like, there arises a problem that what has been done to ensure optical performance (stray light) cannot be improved by affecting the entire optical performance.

[Configuration of the fixing member 5]
As described above, the lens unit 10 is formed with the contact portion 5 a that contacts the edge 3 b of the third lens 3. And the outer peripheral part 5b extended in the outer peripheral direction from the contact part 5a is arrange | positioned so that the one end 4e and the other end 4f of the outer peripheral direction in the side wall 4d of the barrel 4 may be straddled. The fixing member 5 is made of metal, resin, or the like. It is preferable that the fixing member 5 has a roughened surface facing the edge 3b of the third lens 3 (surface facing the third lens 3 of the contact portion 5a). Thereby, the light shielding function can be imparted to the fixing member 5. Then, stray light generated in the lens unit 10 can be prevented. In order to give the fixing member 5 a light shielding function, a black paint may be applied to the surface facing the third lens 3. Furthermore, a black resin may be used as the material of the fixing member 5.

  As described above, if the light shielding function is provided to the fixing member 5, it is not necessary to provide a separate light shielding member, and it is possible to reduce the number of members, the member cost, and the tact time.

  Further, the lens unit 10 may have a configuration in which a light shielding member is provided between the edge 3 b of the third lens 3 and the fixing member 5. Examples of the material of the light shielding member include metal and black resin. According to this configuration, the light shielding function can be easily configured.

  Hereinafter, modified examples of the fixing member 5 will be described.

[Modification 1]
The fixing member 5 may have a configuration in which an inclined portion that is inclined so as to become wider toward the other end opposite to one end in the optical axis direction of the third lens 3 may be formed. Thereby, it is possible to prevent the light beam passing through the lens unit from interfering with the fixing member. Hereinafter, the structure of the fixing member 5 as the modified example 1 will be described with reference to FIGS.

  FIG. 3A is a cross-sectional view of the main part for explaining the light beam when the inclined member is not provided with the inclined member, and FIG. 3B is an inclined member provided with the fixed member. It is sectional drawing of the principal part for demonstrating the light of time. Here, in FIG. 3B, the fixing member is separated from the optical surface portion. However, this is for explaining the relationship between the light beam and the inclined portion provided in the fixing member, and the optical surface portion and the fixing member are The arrangement may be close.

  In the imaging apparatus, when the lens unit 10 is incorporated, the first lens 1, the second lens 2, the third lens 3, the fixing member 5, and the solid-state imaging element are sequentially arranged from the object side to the image plane side. It becomes a distributed configuration. That is, the fixing member 5 is arranged between the lens group including the first lens 1, the second lens 2, and the third lens 3 and the solid-state imaging device. In this case, as shown in FIG. 3A, a part of the incident light beam that has passed through the lens group in the lens unit 10 may be shielded by the inner periphery (contact portion 5 a) of the fixing member 5. There is. In particular, as described above, due to the downsizing and thinning of the camera module, the incident angle of light incident on the solid-state imaging device is increased, which may interfere with the inner periphery of the fixing member having a thickness. .

  Therefore, in the lens unit, as shown in FIG. 3B, it is preferable that the fixing member 5 is provided with an inclined portion 5c that becomes wider from the object side toward the image plane side. By adopting such a configuration, the incident light beam that has passed through the lens group in the lens unit 10 and the fixing member 5 do not interfere with each other. Therefore, a lens unit with good optical performance can be obtained without being affected by the fixing member 5.

  The inclination angle of the inclined portion 5c with respect to the optical axis may be appropriately set as long as it is larger than the incident angle θ of the incident light beam. The incident angle θ can be easily set based on the tangent (tan θ) between the diagonal of the light receiving surface of the solid-state imaging device and the focal length of the camera module (or the height from the sensor surface to the object-side lens surface). Or it may be set in more detail by optical design.

  Specific examples of the lens unit of Modification 1 are shown below.

[Example 1]
In the manufactured camera module, when the height from the sensor surface to the lens surface on the object side is about 4 mm, the diagonal of the sensor is about φ4 mm. At this time, the incident angle θ of the light beam with respect to the optical axis is about 27 degrees. Therefore, if the inclination angle θ ′ with respect to the optical axis of the inclined portion 5c is about 30 degrees, the incident light beam is not hindered.

  Note that the inclination angle θ ′ of the inclined portion 5c with respect to the optical axis may be too large. However, if the inclination angle θ ′ is increased, the surface (pressing area A) for pressing the fixing member 5 is lost, and stray light having a large incident angle may be incident on the sensor without being blocked. is there.

  Accordingly, a configuration in which the end of the inclined portion 5c on the image plane side is located from the outer periphery to the inner periphery of the edge is desirable. This is because if there is no area overlapping the contact surface between the pressing surface and the edge, the lens is not sufficiently pressed or the direction is tilted.

  For example, if the thickness of the fixing member 5 is 0.5 mm (a value that takes into account handling, processing availability, size that does not affect the imaging device, etc.), 0.5 × tan30 = If it is 0.3 mm (inclined part area B) and the edge is 0.4 mm or more, an overlapping area of about 0.1 mm can be secured.

[Modification 2]
Further, the fixing member 5 may have a configuration in which the contact portion 5a and the outer peripheral portion 5b have different thicknesses in the optical axis direction. 4 and 5 are cross-sectional views of the main part showing the configuration of the fixing member 5 as the second modification.

  As described above, the fixing member 5 has a configuration in which the fixing member 5 is disposed between the lens group and the solid-state imaging device. Therefore, since the fixing member 5 needs to be configured not to interfere with the incident light beam, the thickness of the fixing member 5 is limited. As a result, there is a possibility that the strength of the fixing member 5 cannot be obtained sufficiently. In order to ensure the strength of the fixing member 5, the contact portion 5 a and the outer peripheral portion 5 b are configured to have different thicknesses in the optical axis direction, and either on the outer periphery or the inner periphery of the fixing member 5. It is preferable to give a little thickness.

  In the fixing member 5 shown in FIG. 4, the thickness of the contact portion 5a in the optical axis direction is smaller than the thickness of the outer peripheral portion 5b. That is, the outer periphery (outer peripheral portion 5 b) of the fixing member 5 has a little thickness. And the deformation | transformation of the side wall 4d of the barrel 4 can be prevented by separating this outer peripheral part 5b and the side wall 4d of the barrel 4 in an optical axis direction.

  Further, in the fixing member 5 shown in FIG. 5, the thickness of the contact portion 5a in the optical axis direction is larger than the thickness of the outer peripheral portion 5b. That is, the inner periphery (contact portion 5a) of the fixing member 5 is slightly thick. In such a configuration, as shown in the figure, the side wall 4d of the barrel 4 projects from the edge 3b of the third lens 3 toward the image plane side in the optical axis direction. And the deformation | transformation of the side wall 4d of the barrel 4 can be prevented by separating the outer peripheral part 5b and the side wall 4d of the barrel 4 in the optical axis direction.

  4 and 5, the strength of the fixing member 5 can be further ensured without causing deformation of the side wall 4d of the barrel 4 by the fixing member 5. Therefore, handling of the fixing member 5 is facilitated.

  Specific examples of the lens unit of Modification 2 are shown below.

[Example 2]
In the present embodiment, as in the first embodiment, the incident angle θ of the light beam with respect to the optical axis is about 27 degrees. Further, the fixing member 5 in the lens unit of the present embodiment has an inclined portion 5c as in the first embodiment, and the inclination angle is 30 degrees.

  In the said Example 1, the thickness of the fixing member was 0.5 mm. On the other hand, in the present embodiment, the thickness of the fixing member 5 is set to 0.3 mm (manufacturable size). In this case, according to the same calculation as in Example 1 (0.3 × tan 30), the inclined region B is about 0.2 mm, which is smaller than that in Example 1. That is, if the inclined portion region B is reduced, the edge can be reduced (in this case, about 0.3 mm is sufficient). Alternatively, the contact area (pressing area A) with the fixing member 5 can be secured by increasing the edge to reduce the influence on production (for example, prevention of tilting and deformation of the fixing member during pressing). it can. However, if the thickness of the fixing member 5 is reduced, deformation may occur easily. Therefore, it is desirable to adopt a configuration as shown in FIG. 4 or FIG. If the thickest portion of the fixing member 5 is configured to be twice as thick as the thinnest portion, the above-described problems can be improved.

[Arrangement of fixing members]
The positional relationship between the third lens 3 and the fixing member 5 is determined by the interference between the optical surface portion 3a of the third lens 3 and the inner periphery (abutting portion 5a) of the fixing member 5. However, depending on the shape of the optical surface portion 3a of the third lens 3, the positional relationship may not be determined due to the interference. For example, there is a case where the boundary between the effective diameter of the optical surface portion 3a and the edges 3a and 3b is not clear because the curvature of the optical surface portion 3a of the third lens 3 is large. In this case, the positional relationship between the third lens 3 and the fixing member 5 is not fixed, and the fixing member 5 is applied to the optical surface portion 3a of the third lens 3 (the contact portion 5a of the fixing member 5 is the third portion). There is a risk of contact with the optical surface portion 3a of the lens 3).

  Therefore, in the lens unit 10, for example, it is preferable that a part of the edge 3 b of the third lens 3 and an abutting part 5 a of the fixing member 5 are provided with an uneven part that fits each other. That is, it is preferable that the fixing member 5 has a fitting region that fits with the edge 3 b of the third lens 3. Thereby, when positioning the fixing member 5, rough adjustment can be easily performed. This configuration is preferable because, for example, in the production of the lens unit 10, it is possible to reduce the time required for positioning the third lens 3 and the fixing member 5.

  As the configuration having the fitting region in which the fixing member 5 is fitted to the edge 3b of the third lens 3 in this way, for example, the configuration shown in FIG. As shown in the figure, in the fixing member 5, the thickness of the contact portion 5a in the optical axis direction is smaller than the thickness of the outer peripheral portion 5b. That is, the fixing member 5 has a configuration in which a step is formed by the contact portion 5a and the outer peripheral portion 5b. Then, the edges 3a and 3b of the third lens 3 are fitted in the stepped portion.

  In the description so far, the fixing member 5 is separate (separate) from the third lens 3. However, the fixing member 5 is not limited to such a configuration, and may be formed by integral molding with the third lens 3. For example, by forming the fixing member 5 simultaneously with the formation of the third lens 3, the positioning time of the third lens 3 and the fixing member 5 can be made zero. Furthermore, the number of parts can be reduced.

  As a method of integrally forming the fixing member 5 and the third lens 3, for example, a method of forming the fixing member 5 by insert molding at the time of molding the third lens 3, or a fixing member 5 and two-color molding by two-color molding There is a method in which the materials of the third lenses 3 are simultaneously formed and integrated. At this time, it is desirable to confirm in advance by optical design so that the region of the fixing member does not interfere with the optical path of the incident light beam. Since the fixing member 5 and the third lens 3 are integrally formed, the number of parts can be reduced and handling can be facilitated, so that the time in the production of the lens unit can be reduced.

  Insert molding and two-color molding are not currently used for lens parts. However, considering that the conventional method of forming a lens unit by press-fitting a lens into a barrel becomes difficult as the imaging device becomes smaller and thinner, insert molding and two-color molding are not Need to be adopted.

  Insert molding and two-color molding not only have an effect on the configuration of the lens unit, but also enable easy positioning of the fixing member 5 and the third lens 3, so that the optical elements required at the same time as miniaturization and thinning are required. This is also an important method for improving performance. For example, in the insert molding, the fixing member 5 may be disposed at the time of lens molding, and in the two-color molding, the fixing member 5 may be molded after the lens is molded. Regardless of the lens and the fixing member molded by any method, the lens unit can be formed without staining the lens surface.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIG. In addition, about the member similar to Embodiment 1, the same referential mark is attached | subjected and the detailed description is abbreviate | omitted.

  In the lens unit of the first embodiment, the outer periphery of the fixing member 5 has the same size as the outer periphery of the barrel 4. The lens unit of the present embodiment has a configuration in which a part of the outer periphery (outer peripheral part 5 b) of the fixing member 5 extends over the side wall of the barrel 4. FIG. 6 is a plan view showing a schematic configuration of the lens unit 10 of the present embodiment. 7 is a cross-sectional view taken along line AB in FIG.

  As shown in FIG. 6, the outer peripheral portion of the fixing member 5 is a protruding portion 5 d partially protruding in the outer peripheral direction. In the side wall of the barrel 4, several recesses 4 g that are recessed in the optical axis direction are formed. As shown in FIG. 7, the recess 4g is formed so as to surround the protrusion 5d. The recess 4g is formed as a notch on the side wall of the barrel 4. This produces an effect of preventing the surface of the third lens 3 on the imaging side in the completed lens unit from being soiled. This effect will be described in detail below.

  In manufacturing the camera module 100, the sensor 12, the lens unit 10, and the drive mechanism 11 are assembled separately, and then the sensor 12 and the lens unit 10 to which the drive mechanism 11 is attached are adjusted in the optical axis direction. As a result, the lens unit 10 is adjusted to an optimal position for optical performance. Thereafter, the camera module 100 is completed by fixing the lens unit 10 to the drive mechanism 11.

  Therefore, in manufacturing the camera module 100, the lens unit 10 is assembled by inserting the lens group including the first lens 1, the second lens 2, and the third lens 3 into the barrel 4. Thereafter, in order to adjust the sensor 12 and the lens unit 10 in the optical axis direction, the lens unit 10 is temporarily stored in a tray. When storing the assembled lens unit 10 in the tray, it is preferable to store the third lens 3 on the image plane side downward in the optical axis direction. This is because the lens unit 10 taken out from the tray can be attached to the drive mechanism 11 as it is by storing in this way. For this reason, it leads to shortening of production time, and specifically, it is a simple operation of taking out the lens unit 10 and attaching it to the drive mechanism 11.

  As described above, from the viewpoint of shortening the production time, when the assembled lens unit 10 is stored in the tray, there is a production restriction that the third lens 3 on the image plane side is stored on the lower side in the optical axis direction. It will be. In this case, when the lens unit 10 is stored in the tray, the optical surface portion 3c of the third lens 3 comes into contact with the surface of the tray, so that there is a problem that the lens unit 10 is scratched or dirty during transportation. Arise.

  In the lens unit 10 shown in FIG. 6, the concave portion 4 g is provided on the side wall of the barrel 4, and the concave portion 4 g is formed so as to surround the protruding portion 5 d of the fixing member 5. For this reason, when storing the lens unit 10 in a tray, the optical surface part 3a of the 3rd lens 3 does not contact a tray, and the above problems do not arise.

  Here, it is desirable that the side wall of the barrel 4 has a configuration that slightly protrudes toward the image plane side from the optical surface portion 3 a of the third lens 3. The recesses 4g may be provided at several locations. However, considering that the lens group is inserted into the barrel 4 and fixed, a configuration that can apply an equal load to the lens group is desirable.

  For example, what is necessary is just the structure by which the recessed part 4g of at least 3 places was provided in the side wall of the barrel 4 at equal intervals. Thereby, after inserting a lens group in the barrel 4, the load of the jig | tool which hold | maintains a lens group is provided with sufficient balance in the plane perpendicular | vertical with respect to an optical axis. Therefore, the tilt between the barrel 4 and the lens group can be suppressed. Therefore, a camera module with better optical performance can be obtained.

  Another configuration example of the lens unit 10 of the present embodiment will be described below. FIG. 8 is a plan view schematically showing a lens unit 10 as another configuration example.

  As shown in FIG. 8, a groove 5 e is formed in the outer peripheral portion 5 b of the fixing member 5. The groove 5e is formed extending in the optical axis direction. The groove 5 e becomes a clear application region of the adhesive 8 when the side wall of the barrel 4 and the fixing member are fixed by the adhesive 8. Thereby, in the assembly of the lens unit 10, the application time of the adhesive 8 can be shortened, and the curing time of the adhesive 8 can be shortened.

  As the adhesive 8 used for fixing the side wall of the barrel 4 and the fixing member, for example, a photocurable material that is cured by ultraviolet irradiation, a thermosetting material that is cured by heating, or a photocurable material and a thermosetting material are used. Any of the combined hybrid materials may be used. By using a photocurable material as the adhesive 8, the production time can be shortened. On the other hand, since the photocurable material is used for fixing the barrel 4 and the fixing member 5, there is a possibility that the ultraviolet irradiation area for photocuring may be limited. For this reason, there exists a possibility that the unhardened part of the adhesive agent 8 may remain. In this case, after temporarily fixing by photocuring using the adhesive 8 made of the hybrid material, the production time is shortened by separately heating and heating by an oven or the like, and at the same time, the uncured part Can be eliminated.

  As described above, by optimizing the relationship between the side wall of the barrel 4 and the fixing member 5, a configuration that improves the productivity of the lens unit 10 can be realized. Here, the configuration shown in FIG. 6 and the configuration shown in FIG. 8 have been described separately. However, the lens unit 10 is not limited to this configuration, and may have a configuration that combines both the characteristic configurations shown in FIGS. 6 and 8. Thereby, a lens unit with improved productivity can be realized. In FIG. 6, the barrel is protruded from the lens surface, but a similar function may be imparted by causing the fixing member to protrude from the lens surface. Which configuration is used is largely related to the size of the lens unit and the like, and considering the thinning of the barrel side wall, when the lens unit is small, it is preferable to have a configuration in which the fixing member protrudes from the lens surface.

[Assembly method of lens unit]
Here, a method for assembling the lens unit of the present invention will be described.

  As described above, in manufacturing the camera module 100, the sensor 12, the lens unit 10, and the drive mechanism 11 are assembled separately, and then the sensor 12 with the drive mechanism 11 attached and the lens unit 10 are adjusted in the optical axis direction. There are many cases. This is because the repair is facilitated by adjusting the camera module after separately assembling to form a camera module. (Replacing a defective part is often performed during production.) Thus, the lens unit 10 is adjusted to an optimal position for optical performance. Thereafter, the camera module 100 is completed by fixing the lens unit 10 to the drive mechanism 11.

  Therefore, in assembling the lens unit 10, it is required to realize the optical performance of the camera module 100 and to produce (assemble) it in a short time. In other words, in the method of assembling the lens unit 10, mutually contradicting conditions are required, that is, improvement in productivity in assembling in a short time and securing of optical performance.

  In order to satisfy both of the above conditions, the lens unit 10 of the present invention includes a contact portion 5a where the fixing member 5 contacts the edge 3b of the third lens 3, and a side wall of the barrel 4 extending from the contact portion 5a. It has the structure which has the outer peripheral part extended. With this configuration, even when the third lens 3 does not have a sufficient edge 3b and cannot be pressed by a jig for inserting the lens group into the barrel 4, a pressing region is secured by the fixing member 5. be able to. Therefore, it is easy to press the lens group inserted into the barrel 4 with a jig, and the size of the fixing member 5 can be increased. Thereby, handling of the fixing member 5 becomes easy, and furthermore, optical performance can be ensured. That is, the mutually conflicting conditions of ensuring optical performance and improving productivity can be achieved.

The assembling method of the lens unit 10 of the present invention includes:
(1) An insertion step of inserting a lens group including the first lens 1, the second lens 2, and the third lens 3 into the cylindrical barrel 4.
(2) a first pressing step in which the fixing member 5 is disposed so as to contact one end (edge 3b) of the third lens 3 in the optical axis direction, and the fixing member 5 is pressed in the optical axis direction;
(3) A configuration including a fixing step of fixing the barrel 4 and the fixing member 5 together.

  After the lens group including the first lens 1, the second lens 2, and the third lens 3 is sequentially inserted as in the above steps (1) to (3), the edge 3b of the third lens 3 is inserted. It is pressed in the direction of the optical axis via the abutting fixing member 5. Thereafter, the lens unit 10 is completed by fixing the barrel 4 and the fixing member 5 together. According to this configuration, it is possible to assemble the lens unit in a lump without fixing the individual lenses to each other. Therefore, the manufacturing time can be shortened.

  In order to secure the optical performance of the lens unit, the first lens 1, the second lens 2, and the third lens 3 are fixed to each other with an adhesive or the like to form a lens group, and then the lens group is mounted on the barrel 4. Is considered ideal. However, in practice, when individual lenses are fixed to each other with an adhesive or the like to form a lens group, the adhesive flows out between the edges of the individual lenses, which may cause the lens group to tilt. understood. Further, when the outer peripheral portions (edges) of the lenses are fixed with an adhesive, the adhesive may be diffused outside the lens edge. As a result, the formed lens group becomes larger than the outer periphery of the plurality of lenses by the amount of the solidified adhesive. Further, it has been found that sufficient optical performance cannot always be obtained due to problems such as interference of the solidified adhesive with the inner wall of the barrel.

  Further, the problems due to interference include (1) poor press-fit that affects the press-fit and causes tilting, etc. (2) reduced optical performance due to solidified material peeled off due to interference becoming dust and adhering to the lens. There is something like this.

  Therefore, after the lens group including the first lens 1, the second lens 2, and the third lens 3 is sequentially inserted, the optical axis is passed through the fixing member 5 that is in contact with the edge 3 b of the third lens 3. It is possible to assemble the lens unit in a batch by pressing in the direction. In addition, it is possible to ensure the fitting accuracy between the individual lenses, and there is no interference of the adhesive between the lens group and the inner wall surface of the barrel 4. Therefore, according to the lens unit assembling method of the present invention, it is possible to obtain a lens unit with good optical performance. In fixing the barrel 4 and the fixing member 5, it is preferable to use an adhesive that does not deteriorate the optical performance of the lens unit. Examples of such an adhesive include an adhesive that does not change with time and an adhesive that is resistant to drop impact resistance. Examples of another method for fixing the barrel 4 and the fixing member 5 include laser welding and heat caulking. Normally, the lens unit is fixed in consideration of damage due to impact during use, degradation of optical performance, etc., but a configuration in which the lens is simply press-fitted into the barrel may be employed.

  In the lens unit 10 described above, the barrel 4 has a first opening 4a having an inner diameter smaller than the outer shape of the first lens 1 at one end on the object side, and a third at the other end on the image plane side. It has the structure which has the 2nd opening part 4b which has the same internal diameter as the external shape of the lens 3 of this. In this configuration, the first lens 1, the second lens 2, and the third lens 3 are sequentially inserted from the image plane side of the barrel 4, and the fixing member 5 is disposed so as to contact the third lens 3. It has been configured. In such a configuration, the first opening 4 a on the object side can be used as the stop of the lens unit 10. Therefore, according to the lens unit 10, it is not necessary to newly provide a diaphragm, and the number of parts can be reduced.

  The position of the stop can be appropriately determined by optical design in order to optimize the optical system of the lens unit. By setting the aperture position closer to the object side, it is possible to further reduce the size and thickness of the camera module.

  Furthermore, the center of the barrel 4 and the optical axis of the lens group may be made to coincide with each other by using the boundary between the optical surface portion and the edge of each lens constituting the lens group and the stop or the first opening 4a. it can.

  Another configuration of the barrel 4 may be a configuration in which the first opening 4a is formed at one end on the image plane side and the second opening 4b is formed at the other end on the object side. . In this case, since the area of the planar portion of the fixing member 5 can be increased, the lens unit 10 can be assembled with higher stability.

As shown in FIG. 4B, when the edge 3a, 3b of the third lens 3 and the fixing member 5 are fitted, the assembly includes the following steps (i) to (iii). The method can also be adopted.
(i) a step of fitting the third lens 3, the second lens 2, and the first lens 1 in this order with the fixing member 5 on the reference plane, and assembling a lens group held by the fixing member;
(ii) A step of inserting the lens group into the barrel 2 by placing the barrel 2 on the lens group and pressing the end of the barrel 2 in the optical axis direction with a jig (second pressing step);
(iii) A step of fixing the fixing member 5 and the barrel 2 with an adhesive or the like.

  Here, the adhesive used in the step (iii) may be applied after the step (i). After that, step (ii) may be performed, and the barrel 2 and the fixing member 5 may be bonded and fixed by pressing.

  As described above, the assembly method in which the adhesive used in the step (iii) is applied after the previous step (i) (the reverse of the previous assembly procedure) is effective in the following points.

(1) When the reference plane of the lens unit 10 is on the image plane side Here, the reference plane of the lens unit 10 is a plane that is used as a reference when assembling a plurality of lenses. By using the lens (A) having a large influence as a reference surface, even if other lenses are assembled, the lens unit can have a small error with respect to the lens A (a highly accurate lens unit). be able to).

(2) When the tilt between the lens unit 10 and the image sensor is minimized When the lens unit 10 is assembled with respect to the barrel surface on the object side, if the barrel 2 is adjusted, the assembly will inevitably occur due to screw variations. An error occurs. Therefore, the lens is optimized by simulation so that the lens unit 10 allows the error. However, when miniaturization / thinning like a camera module and high-precision optical performance are required, it is difficult to allow an error in lens optimization. Therefore, in order to suppress the allowable error range, the accuracy of parts and assembly is improved.

  Improving the accuracy of a component leads to an increase in component cost and cannot be employed. Therefore, it is necessary to take measures by reviewing the assembly method.

  In this configuration, since the reference plane and the image sensor can be closest, a highly accurate lens unit can be obtained by a simple assembly method.

  In addition, it can be moved to a tray and packed as it is in production, and can also be used in that state when assembling the imaging device, so it is possible to reduce extra tact time. is there. In other words, the structure in which the fixing member is pressed during production is in the reverse state, and a process of reversing the top and bottom is required when assembling the imaging device.

  Furthermore, since the performance of the lens unit can be evaluated in the state after the lens unit is completed, the yield of the lens unit and the imaging apparatus using the lens unit can be improved.

[Imaging device having lens unit 10 and electronic apparatus equipped with imaging device]
So far, the configuration of the lens unit 10 of the present invention and the assembling method thereof have been described. The present invention includes a camera module (imaging device) 100 in which the lens unit 10 is mounted, and an electronic device in which the camera module 100 is mounted. A mobile phone can be used as the electronic apparatus of the present invention. However, the electronic device of the present invention is not limited to a mobile phone, and includes other electronic devices such as a digital still camera and a video camera. The imaging device of the present invention includes the imaging device mounted on the electronic device exemplified above.

  In particular, in recent years, there is a high demand for downsizing and thinning of electronic devices, so that by mounting an imaging device using the lens unit of the present invention, a new application in which the imaging device is installed in an electronic device is realized. Can do.

  Furthermore, in recent years, in order to realize safe driving, an imaging device may be mounted on an automobile, or a camera module (imaging device) for in-vehicle use. Even in the case of a camera module mounted on an automobile, it is effective because there is an increasing demand for a small and thin camera module that can be incorporated in order not to impair the appearance of the automobile.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The lens unit of the present invention can be widely used in electronic devices such as mobile phones, digital still cameras, and video cameras.

It is sectional drawing which shows schematic structure of the imaging device of one Embodiment of this invention. It is sectional drawing which shows schematic structure of the lens unit of one Embodiment of this invention. (A) is sectional drawing of the principal part for demonstrating the light ray when the inclination part is not provided in the fixing member, (b) is the light ray when the inclination part is provided in the fixing member. It is sectional drawing of the principal part for demonstrating. (A) is sectional drawing of the principal part which shows the structure of the fixing member as the modification 2, (b) is a structure shown by (a), and a fixing member fits the edge of a 3rd lens. It is sectional drawing of the principal part which shows the structure which has a fitting area | region to match. FIG. 10 is a cross-sectional view of a main part showing a configuration of a fixing member as a second modification. It is a top view which shows schematic structure of the lens unit of the other form of implementation of this invention. FIG. 7 is a cross-sectional view taken along line AB in FIG. 6. It is a top view which shows the outline of the lens unit as another structural example of FIG.

Explanation of symbols

1 1st lens 1a edge (outer edge part)
1c Optical surface part 2 2nd lens 2a * 2b edge (outer edge part)
2c Optical surface part 3 3rd lens 3a * 3b Edge (outer edge part)
3c Optical surface part 4 Barrel 4a 1st opening part 4b 2nd opening part 4c Aperture part 4d Side wall 4g Recessed part 5 Fixing member 5a Abutting part 5b Outer peripheral part 5c Inclined part 5d Protruding part 5e Groove part 6 Agent 10 Lens unit 11 Drive mechanism 12 Sensor 12a Solid-state imaging device (imaging device)
100 Camera module (imaging device)

Claims (19)

A lens composed of an optical surface portion having optical characteristics, and an outer edge portion surrounding the optical surface portion;
A cylindrical barrel that houses the lens;
A lens unit including a fixing member that fixes one end of the lens in the optical axis direction,
The lens unit, wherein the fixing member has an abutting portion that abuts on an outer edge portion while avoiding an optical surface portion of the lens, and an outer peripheral portion that extends from the corresponding portion to the side wall of the barrel.   The lens unit according to claim 1, wherein the fixing member has an outer periphery having the same size as the barrel.   The lens unit according to claim 1, wherein the outer peripheral portion is separated from a side wall of the barrel in an optical axis direction.   The lens unit according to claim 1, wherein a light shielding member is provided between the fixing member and an outer edge portion of the lens.   The lens unit according to claim 1, wherein the fixing member has a light shielding function.   6. The inclined portion according to claim 1, wherein the fixing member has an inclined portion that is inclined so as to become wider toward the other end opposite to the one end of the lens. Lens unit.   The lens unit according to claim 1, wherein the abutment portion and the outer peripheral portion of the fixing member have different thicknesses in the optical axis direction.   The lens unit according to claim 1, wherein the fixing member has a fitting region that fits with the outer edge portion of the lens.   The lens unit according to claim 1, wherein the fixing member is formed integrally with the lens. The outer peripheral portion of the fixing member is a protruding portion that partially protrudes toward the side wall of the barrel,
The lens unit according to claim 1, wherein a concave portion that is recessed so as to surround the protruding portion is formed on a side wall of the barrel.   The lens unit according to claim 1, wherein a groove portion is formed on an outer peripheral portion of the fixing member. A lens unit for entering a light beam from an object and forming an image on an image sensor;
The lens is composed of a plurality of lenses in contact with each other in the optical axis direction,
The area of the optical surface portion of the lens disposed on the image plane side among the plurality of lenses is larger than the area of the optical surface portion of the lens disposed on the object side. The lens unit according to any one of the above.   The lens unit according to claim 12, wherein the contact portion of the fixing member is in contact with the outer edge portion of the lens disposed closest to the image plane among the plurality of lenses.   The lens unit according to claim 12, wherein the abutting portion of the fixing member abuts on the outer edge portion of the lens arranged closest to the object side among the plurality of lenses. The lens unit according to any one of claims 1 to 14,
An imaging apparatus comprising: an imaging element.   An electronic apparatus comprising the imaging device according to claim 15. An insertion step of inserting a lens into a cylindrical barrel;
A first pressing step of disposing a fixing member so as to abut one end of the lens in the optical axis direction and pressing the fixing member in the optical axis direction;
A method of assembling a lens unit, comprising a fixing step of fixing the barrel and the fixing member. A fitting process for fitting the lens to the fixed member;
An application step of applying an adhesive to the outer peripheral portion extending from the fitting portion of the lens in the fixing member to the outer periphery,
A second pressing step of covering the lens with a cylindrical barrel and pressing the barrel in the optical axis direction;
A lens unit assembling method comprising a fixing step of fixing the fixing member and the barrel.   19. The lens unit assembling method according to claim 18, wherein the coating step is performed after the second pressing step.

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