JP2011133509A - Method for assembling camera module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the assembling time by shortening the time required for optical axis alignment, and to simplify the brightness control of chart imaging illumination, thereby contributing to reduction in the cost. <P>SOLUTION: For an imaging unit for assembling, a chart with an alignment mark irradiated from a light source is imaged by an imaging device through a reference lens adjusted to a required optical axis position and then, the attitude of the imaging unit is controlled so as to perform alignment to the optical axis position, based on the mark position information of the imaged image. Meanwhile, for a lens unit for assembling, the chart with the mark is imaged by a reference imaging device adjusted to the optical axis position through the lens and then, the attitude of the lens unit is controlled so as to perform alignment to the optical axis position, based on the mark position information of the imaged image. The lens unit whose attitude is controlled and the imaging unit whose attitude is controlled are joined to each other and fixed by an adhesive (completion of the assembling of a camera module). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for assembling a camera module, and more particularly to a method for assembling a camera module in which optical axes of a lens unit and an imaging unit are aligned.

  Many recent portable information terminals such as cellular phones and PDAs are provided with built-in image processing functions, and one of them includes an imaging device. The imaging apparatus includes a lens, a lens barrel that holds the lens, an imaging element that captures a subject image formed through the lens and outputs an imaging signal, a signal processing unit that inputs the imaging signal and performs signal processing, and the like. It has a configured camera module.

  In a camera module having high resolution, when mounting a lens unit (a lens and a lens barrel holding the lens) on a substrate, it is generally performed while adjusting the mounting angle of the lens unit. This is because there is an attachment angle error in each of the lens unit and the image pickup unit (the image pickup element and the holder for fixing and holding it) mounted on the substrate. This is called “tilting”, and the optical axis direction of the lens unit does not match the normal direction of the image sensor (that is, the light receiving surface of the image sensor is tilted with respect to the optical axis of the lens). In addition, light from the imaging target is incident in an oblique direction, aberration occurs in the light beam formed on the imaging element, blurring occurs in the captured image, and image quality is degraded. In addition, this “tilting” causes problems such as a shallower depth of focus, which hinders the increase in the number of pixels.

  Therefore, when assembling the camera module, it is necessary to perform positioning (hereinafter, also referred to as “optical axis alignment”) so that the light receiving surface of the imaging device is accurately orthogonal to the optical axis of the lens. In addition, as the lens and the image sensor become smaller, the influence of the inclination of the light receiving surface of the image sensor on the image quality with respect to the optical axis of the lens becomes larger, so that strict optical axis alignment is required.

  As a conventional method, there is a method of performing optical axis alignment using resolution and contrast information of an image captured from an image sensor. An image captured from the imaging device is obtained by imaging a chart in which a predetermined pattern (for example, a black and white check pattern) is arranged, and a light source (illumination) for illuminating the chart at the time of imaging. Is used.

  Judgment whether or not the optical axis is in the ideal position is calculated by calculating the above resolution and contrast information as evaluation numerical information, and using the evaluation numerical value obtained based on the image data previously captured by a precise camera as the reference data. A method of approaching this reference value, a method of searching for a peak position of an evaluation numerical value obtained from image data, and the like are employed.

  If the above method is used to detect the optical axis position, the information of one captured image indicates the current direction (for example, if the Z-axis direction is parallel to the optical axis, the direction is upward or downward) Since it is impossible to predict how much the optical axis is shifted (if it is tilted with respect to the XY plane orthogonal to the axis, whether it is in the right direction or the left direction), it is necessary to capture image information at least at several points. In other words, from the evaluation numerical value obtained based on the image information captured for each point, search by moving the lens or the image sensor a plurality of times until the peak position of the evaluation numerical value comes out, or until the reference numerical value is reached It is necessary to align the optical axis by moving the image sensor multiple times and searching for it.

  As a technique related to the optical axis alignment described above, for example, there is a camera module production method described in Patent Document 1 below. In this method, the lens barrel is positioned so that the optical axis of the lens is orthogonal to the light receiving surface of the imaging device, and a predetermined test pattern is positioned in front of the positioned lens barrel so that the test pattern is formed on the imaging device. An image is picked up, and the position of the image pickup unit with respect to the lens barrel is adjusted based on the picked-up image of the test pattern.

  Further, as another technique related to this, the following Patent Document 2 discloses that a part of a plurality of lenses constituting a lens system is a fixed lens, and an adjustment lens that is another lens is an optical axis of the fixed lens. A technique is disclosed in which the optical axes of the fixed lens and the adjustment lens are made to coincide with each other by moving in the vertical direction. In the lens optical axis adjustment device disclosed herein, an adjustment lens support member movable in a direction orthogonal to the optical axis is further provided with respect to the fixed lens, and the adjustment is performed in the opening of the end portion of the support member. A cylindrical elastic chuck member that supports the lens by fitting is provided.

  As another technique, there is a camera module manufacturing method described in Patent Document 3 below. In this method, the housing of the autofocus motor and the carrier are fixed on the imaging holder, and the lens unit is housed in a state where it can be rotated in the carrier, and then the lens unit is taken in from the imaging device while being rotated in the carrier. Based on the image data information, the fixed position of the lens unit is determined so that the tilt angle of the image sensor and the tilt angle of the lens unit are offset, and the lens unit is bonded to the carrier at the fixed position.

JP 2005-86659 A JP 2003-66302 A JP 2007-333987 A

  As described above, the method of performing optical axis alignment using the resolution and contrast information of the image captured from the image sensor requires multiple image captures by the image sensor and multiple movements of the lens or image sensor position. Since image processing performed when an image is captured and calculation for obtaining a required movement amount are required, considerable time is required to perform optical axis alignment. Therefore, there has been a problem that it takes a long time to combine the lens unit and the imaging unit after completing the optical axis alignment and complete the assembly as a camera module.

  In addition, if the brightness of the light source (illumination) for imaging the chart used for optical axis alignment changes, the resolution and contrast of the captured image will be affected, and the calculated evaluation value will vary greatly. Therefore, it is necessary to perform management for keeping the image constant or correction such as brightness adjustment. For this reason, there has been a problem that the luminance management of illumination is complicated and complicated, and the cost required for this is increased.

  The present invention was created in view of the problems in the prior art, and shortens the time required for optical axis alignment, thereby shortening the assembly time, simplifying the luminance management of the chart imaging illumination, and reducing the cost. It is an object to provide a method for assembling a camera module that can contribute to the above.

  In order to solve the above-described problems of the prior art, according to one aspect of the present invention, a lens unit having a lens and a lens barrel holding the lens, and an imaging unit having an imaging element and a holder for holding the imaging element are provided. A method for assembling a camera module, wherein a reference lens in which a mark chart in which a plurality of alignment marks illuminated by light from a light source are arranged is adjusted to a required optical axis position with respect to the imaging unit Then, based on the mark position information of the captured image, the orientation of the imaging unit is controlled so as to match the optical axis position, and the mark unit is After the attached chart is imaged with the reference imaging device adjusted to the optical axis position via the lens, based on the mark position information of the captured image, A camera module characterized in that the attitude of the lens unit is controlled so as to match the optical axis position, and the lens unit barrel and the holder of the imaging unit, each of which is attitude-controlled, are fixed by bonding. An assembly method is provided.

  According to the method for assembling a camera module according to one aspect of the present invention, a predetermined chart (with a plurality of alignment marks arranged) is attached to the imaging unit for assembly via the reference lens. Then, based on the information (mark position information) of the captured one image, attitude control of the imaging unit is performed so as to match the optical axis position of the reference lens. Similarly, also for the lens unit for assembly, the marked chart is imaged by the reference imaging element through the lens, and the reference imaging element is based on the information (mark position information) of the captured one image. The attitude of the lens unit is controlled so as to match the optical axis position.

  As described above, according to the present invention, since the image capturing by the imaging device (or the reference imaging device) is performed once for each of the imaging unit and the lens unit, the time required for optical axis alignment can be shortened. As a result, it is possible to shorten the time (assembly time) required for combining the lens unit and the imaging unit after completing the optical axis and completing the assembly as a camera module.

  In addition, since a chart in which a plurality of alignment marks are arranged is used for the chart imaged by the image sensor (or the reference image sensor), even if the luminance of the light source (illumination) for chart imaging changes. The evaluation value to be obtained does not fluctuate greatly without being influenced by the resolution and contrast of the captured image. This eliminates the need for management to keep the illumination brightness constant and correction such as brightness adjustment as required in the prior art, thus simplifying the brightness management of the lighting and reducing costs. Can contribute.

It is a figure which shows schematically the structure of the assembly apparatus for enforcing the assembly method of the camera module which concerns on one Embodiment of this invention. It is a figure which shows an example of the chart with an alignment mark used in the assembly apparatus of FIG. It is a flowchart which shows an example of the assembly method of the camera module performed using the assembly apparatus of FIG. FIG. 4 is a diagram for supplementarily explaining processing (steps S11 to S17) related to “attitude control of the imaging unit” shown in FIG. 3, and (a) is a diagram illustrating a device configuration when the processing is performed; ) Is an explanatory diagram of posture control. FIG. 4 is a diagram for supplementary explanation of processing (steps S21 to S27) related to “lens unit attitude control” shown in FIG. 3, and is a diagram showing an apparatus configuration when the processing is performed. FIG. 4 is a diagram for supplementarily explaining a process (S31 to S37) related to “assembly” shown in FIG. 3, and a diagram showing a device configuration when the process is performed. FIG. 4 is a diagram for supplementarily explaining processing (S12, S13, S22, S23) related to “imaging chart with alignment mark and measurement of mark position” shown in FIG. 3;

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a schematic configuration of an assembling apparatus for carrying out a camera module assembling method according to an embodiment of the present invention when viewed from the side.

  A camera module assembling method and an assembling apparatus using the same according to the present embodiment include a center position of a lens optical axis (a position in an XY plane orthogonal to the optical axis), a tilt (tilt of the lens with respect to the XY plane), and a focus. The position (position in the Z-axis direction), the center position of the image sensor (position in the XY plane), the tilt (tilt of the image sensor with respect to the XY plane), and the imaging position (position in the Z-axis direction) are mounted together. Applies to products that need to be. However, it may not be necessary to perform alignment in the Z-axis direction for products having an autofocus function.

  First, the camera module 10 assembled by the assembly apparatus 50 of this embodiment will be described. As shown in FIG. 6, the camera module 10 to be assembled basically includes a lens 11, a lens barrel 12 (lens unit 13) that fixes and holds the lens 11, an image sensor 14, and the lens element 13. A holder 15 (imaging unit 16) that is fixedly held is provided. Furthermore, a signal processing unit (not shown) such as a DSP (digital signal processor) that receives an image signal output from the image sensor 14 and performs predetermined signal processing is provided.

  The lens barrel 12 is formed in a cylindrical shape, and the lens 11 is fixedly held inside the cylindrical portion so that the optical axis of the lens 11 coincides with the axis of the cylindrical portion. The holder 15 is configured in a rectangular plate shape, and a rectangular recess is formed on the surface facing the lens barrel 12 (lens 11), and the image sensor 14 is accommodated and held in the recess. The image sensor 14 is composed of a CCD sensor, a CMOS sensor, or the like, and is sealed with a transparent glass incorporated in a recess. The signal processing unit that is electrically connected to the image sensor 14 is provided on the surface of the holder 15 opposite to the side where the recess is formed.

  Although not particularly illustrated, the end surface of the lens barrel 12 in the lens unit 13 (the surface facing the imaging unit 16 side) and the end surface of the holder 15 in the imaging unit 16 (the side facing the lens unit 13 side). In this state, an adhesive is filled in the gap in a state where a slight gap is secured, so that the lens unit 13 and the imaging unit 16 are fixed, and the camera module 10 is configured. It has become.

  Next, the assembling apparatus 50 for assembling the camera module 10 will be described. As shown in FIG. 1, the assembling apparatus 50 basically includes an actuator 20 for the lens unit 13, an actuator 25 for the imaging unit 16, and a plurality of alignment marks to be described later. A chart 30 and a light source 32 for irradiating the chart 30 and a control device 40 operatively connected to the actuators 20 and 25 and the imaging unit 16 are provided.

  The actuators 20 and 25 each have a function of mechanically supporting the assembling lens unit 13 and the imaging unit 16 and moving or rotating the supported positions (postures) in a plurality of directions. . In this embodiment, the plurality of directions are six directions (see FIG. 4B), the Z-axis direction parallel to the optical axis of the lens, the X-axis direction and the Y-axis orthogonal to each other in a plane orthogonal to the optical axis. Direction, Z-axis, X-axis, and Y-axis, respectively, θ direction, ψ direction, and φ direction that rotate about the center.

  The actuator 20 for the lens unit 13 includes a base 22 disposed on a rail 21 fixed in a plane parallel to the X-axis direction and the Y-axis direction, and an attitude adjustment connected to the base 22. A mechanism 23 (mechanism for adjusting the posture of the lens unit 13 in the six-axis direction) and a holding unit 24 that is mechanically coupled to the posture adjustment mechanism 23 and holds the lens unit 13 in a detachable manner. . Similarly, the actuator 25 for the image pickup unit 16 includes a base 26 disposed on the rail 21 and a posture adjusting mechanism 27 connected to the base 26 (the posture of the image pickup unit 16 in the six axis directions described above). And a holding portion 28 that is mechanically coupled to the upper end portion of the posture adjusting mechanism 27 and holds the imaging unit 16 in a detachable manner.

  The actuators 20 and 25 are arranged so as to be movable on the rails 21. That is, the bases 22 and 26 of the actuators 20 and 25 are moved along the rails 21, so that the stations (adjustment positions) for adjusting the postures of the lens unit 13 and the imaging unit 16 are adjusted. , 16 can be reciprocated between stations (assembly positions) for assembling.

  A master lens unit 13M (FIG. 4), which will be described later, is disposed at the adjustment position where the imaging unit 16 is positioned, instead of the lens unit 13 for assembly. The form and arrangement of the master lens unit 13M will be described later. On the other hand, a master imaging unit 16M (FIG. 5), which will be described later, is disposed at the adjustment position where the lens unit 13 is positioned, instead of the imaging unit 16 for assembly. The form and arrangement of the master imaging unit 16M will be described later.

  The light source 32 is positioned above the imaging unit 16 and the lens unit 13 as shown in the figure, and is arranged so as to irradiate the chart 30 disposed on the light emitting surface side thereof. The chart 30 is arranged in parallel with the light emitting surface of the light source 32 so that the relative positional relationship with the light source 32 is fixed. The light source 32 and the chart 30 whose positional relationship is fixed may be arranged at three positions, that is, the adjustment position of the lens unit 13, the adjustment position of the imaging unit 16, and the assembly position, or each actuator. You may make it arrange | position so that a movement is interlocked with the reciprocation of 20 and 25 (movement between an adjustment position and an assembly position). In the latter case, only one set of the light source 32 and the chart 30 is required, which is advantageous in terms of cost.

  As shown in FIG. 2 as an example, the chart 30 illuminated with light from the light source 32 has alignment marks A, B, C, D, and E arranged at five points. More specifically, A, B, D, and C marks are arranged in the clockwise direction near each corner on one surface of a square (square or rectangular as shown) substrate. The mark E is arranged at the center (the position where the diagonal connecting A and D intersects with the diagonal connecting B and C). As shown in the figure, the chart 30 with alignment marks is arranged such that the direction from the mark A to B coincides with the X axis in the left-handed orthogonal coordinates, and the direction from the mark A to C coincides with the Y axis.

  A light transmissive material is used for the base material of the chart 30. As a result, the alignment marks A, B, C, D, and E of the chart 30 illuminated with light from the light source 32 (FIG. 1) pass through the base material and pass through the imaging unit 16 (the light receiving surface of the imaging element 14). ).

  The control device 40 cooperates with the actuators 20 and 25 and the imaging unit 16 for assembly (or the master imaging unit 16M) to control processes necessary for optical axis alignment and various processes associated therewith. Is to do. Since it is necessary to process the captured image of the chart 30 with alignment marks when performing optical axis alignment, the control device 40 is equipped with a required image processing function. As the control device 40 equipped with such an image processing function, for example, a personal computer (PC) can be used. Such a PC includes an input device (such as a keyboard and a mouse) and an output device (such as a display) as well as a recording medium (storage unit) such as an HDD.

  In the storage unit (not shown) of the control device 40, the marks A, B, C, D, and E in the XY plane obtained based on the image data of the chart 30 with alignment marks previously captured by a precise camera are stored. Information on the position at (hereinafter referred to as “reference data”) is stored. As will be described later, the reference data is appropriately referred to when the optical axes of the lens unit 13 for assembly and the imaging unit 16 for assembly are aligned.

  The control device 40 compares the image data (imaging information of the chart 30 with the alignment mark) captured from the imaging device 14 (or the imaging device of the master imaging unit 16M) and the reference data stored in the storage unit, Based on the comparison result, it is determined whether the position (posture) of the lens unit 13 and the position (posture) of the image pickup unit 16 match the required optical axis position. When it is determined that it does not match the required optical axis position, the actuators 20 and 25 are controlled so as to correct the positions of the lens unit 13 and the imaging unit 16, respectively, as will be described later. That is, control is performed so as to move or rotate in the directions of the six axes (X, Y, Z, θ, ψ, φ shown in FIG. 4B).

  Hereinafter, an assembling method of the camera module 10 according to the present embodiment will be described with reference to FIG. In addition, a supplementary explanation will be given with reference to FIGS.

  Of the processing steps shown in FIG. 3, the processing performed in steps S11 to S17 and the processing performed in steps S21 to S27 are not performed in parallel. That is, the other process is performed after the end of one process, and the subsequent order is not particularly limited.

<Attitude control of imaging unit 16 ... steps S11 to S17>
FIG. 4A schematically shows a device configuration when processing related to attitude control of the imaging unit 16 is performed. This device configuration corresponds to the configuration when the six-axis actuator 25 for the imaging unit 16 moves to the “adjustment position” based on the control from the control device 40 and supports the imaging unit 16 at that position. Yes.

  In this apparatus configuration, the master lens unit 13M is used. Similar to the assembling lens unit 13, the master lens unit 13M includes a master lens 11M and a lens barrel 12M that fixes and holds the master lens 11M. However, the master lens 11M is adjusted in advance so as to coincide with a required optical axis position. The master lens unit 13M is fixed and held at the same position as the position where the lens unit 13 for assembly is held by a support mechanism (not shown) fixed in a plane parallel to the X-axis direction and the Y-axis direction. ing.

  In this apparatus configuration, an imaging unit 16 for assembly is supplied in the first step S11. This is performed by attaching the imaging unit 16 to the holding portion 28 (FIG. 1) of the actuator 25 via an attachment mechanism (not shown).

  In the next step S <b> 12, the image of the alignment mark added chart 30 is taken into the image pickup device 14 of the image pickup unit 16. That is, the image of the chart 30 with the alignment mark illuminated by the light from the light source 32 is formed on the light receiving surface of the image sensor 14 via the master lens 11M, and the chart 30 is imaged.

  In the next step S13, the positions of a plurality of marks A, B, C, D, and E (FIG. 2) on the chart 30 are measured from the information of the image captured by the image sensor 14. That is, the X coordinate and Y coordinate of each mark are obtained.

  In the next step S14, the measured positions of the marks A, B, C, D, E (X coordinate, Y coordinate) and the respective reference positions (reference data stored in the storage unit of the control device 40) To find the difference. That is, the amount of deviation of each mark position from the respective reference position (the amount of positional deviation in the six-axis directions (X, Y, Z, θ, ψ, φ) of the image sensor 14) is calculated.

  This calculation process is desirably performed using the normalized correlation method for the following reason. The conventional method of performing optical axis alignment using the resolution and contrast information of the image captured from the image sensor is extremely sensitive to changes in the density of the captured image. This is because inconvenience that the range cannot be defined may occur. However, when the normalized correlation method is used, the range is normalized even if a change in density occurs, and thus the calculated evaluation value can be easily determined.

  In this step, when calculating the deviation amount, the distance and angle between the marks (A, B, C, D, E), the center coordinates of a circle passing through each mark, and the like are also calculated, thereby obtaining a captured image. Distortion (tilting), expansion / contraction (Z-axis direction), and center deviation (in the XY plane) can be recognized.

  For example, when a measurement result as shown in FIG. 7A is obtained, the distance between the marks AB and the distance between the marks CD, the distance between the marks AC and the distance between the marks BD, and the distance between the marks AD. The distance between the mark BC and the mark BC is compared, and the calculated values are compared with the reference value, whereby the expansion and contraction (Z-axis direction) of the image can be detected.

  When the measurement results as shown in FIGS. 7B and 7C are obtained, the distance between the marks AB and the distance between the marks CD, the distance between the marks AC and the distance between the marks BD, By obtaining ACD and ∠ABD, ∠BAC and ∠BDC, and comparing each obtained value with a reference value, it is possible to detect image distortion (in this case, the tilt of the image sensor 14: tilt).

  Further, the center coordinates of a circle passing through marks A, B, and C, the center coordinates of a circle passing through marks B, C, and D, the center coordinates of a circle passing through marks C, D, and A, and a circle passing through marks D, A, and B By detecting the center coordinates of the image and comparing each of the obtained values with a reference value, it is detected in which direction the displacement (in this case, the displacement of the center position of the image sensor 14) occurs on the XY plane. Can do.

  Alternatively, it is also possible to detect the center deviation by obtaining the difference between the coordinate of the intersection point between the line connecting the marks AD and the line connecting the marks BC and the position coordinate of the mark E and comparing it with the reference value.

  In the next step S15, the position of the image sensor 14 is corrected so as to cancel out the calculated shift amounts (X, Y, Z, θ, ψ, φ). That is, based on the calculated amount of deviation, the amount of movement of the position of the image sensor 14 required to match the optical axis position of the master lens 11M is calculated and obtained. Then, the control device 40 drives the 6-axis actuator 25 based on the obtained movement amount to correct the position of the image pickup device 14 (attitude control of the image pickup unit 16).

  In the next step S16, the position (X coordinate, Y coordinate) of each mark A, B, C, D, E is measured from the information of the image captured by the image sensor 14 in the same manner as the processing performed in step S13. To do.

  In the next step S17, it is determined whether the error (shift amount between the mark position and the reference position) obtained in the same manner as the processing performed in step S14 in the control device 40 is very small (YES) or not (NO). To do. If the determination result is YES, the process proceeds to step S31 (end of “posture control of the imaging unit 16”), and if the determination result is NO, the process returns to step S14 and the above processing is repeated.

<Attitude control of lens unit 13 ... steps S21 to S27>
FIG. 5 schematically shows an apparatus configuration when processing related to posture control of the lens unit 13 is performed. This device configuration corresponds to the configuration when the 6-axis actuator 20 for the lens unit 13 is moved to the “adjustment position” based on the control from the control device 40 and the lens unit 13 is supported at that position. Yes.

  In this apparatus configuration, the master imaging unit 16M is used. Similar to the imaging unit 16 for assembly, the master imaging unit 16M includes a master imaging device 14M and a holder 15M that fixes and holds the master imaging device 14M. However, the master image pickup device 14M is adjusted in advance so as to coincide with a required optical axis position (a light receiving surface whose surface direction is orthogonal to the lens optical axis). The master imaging element 14M is fixed and held at the same position as the position where the imaging unit 16 for assembly is held by a master imaging unit support mechanism 29 fixed in a plane parallel to the X-axis direction and the Y-axis direction. Yes.

  In this apparatus configuration, in the first step S21, the lens unit 13 for assembly is supplied. This is performed by attaching the lens unit 13 to the holding portion 24 (FIG. 1) of the actuator 20 via an attachment mechanism (not shown).

  In the next step S22, the image of the chart 30 with the alignment mark is taken into the fixed master imaging device 14M. That is, the image of the chart 30 with the alignment mark illuminated by the light from the light source 32 is formed on the light receiving surface of the master imaging element 14M via the lens 11, and the chart 30 is imaged.

  In the next step S23, the positions (X coordinate, Y coordinate) of a plurality of marks A, B, C, D, and E (FIG. 2) on the chart 30 are measured from the information of the image captured by the master image sensor 14M. To do.

  In the next step S24, in the same way as the processing performed in the above step S14, the deviation amounts of the positions of the marks A, B, C, D, E from the respective reference positions (in this case, the six axes of the lens 11). The direction (the amount of positional deviation in X, Y, Z, θ, ψ, φ) is calculated. This calculation process is performed using the normalized correlation method as in the above case.

  In addition, recognition of distortion (tilt), expansion / contraction (Z-axis direction), and center shift (in the XY plane) of the captured image is the same as in the above case.

  In the next step S25, the position of the lens 11 is corrected so as to cancel the calculated shift amounts (X, Y, Z, θ, ψ, φ). That is, based on the calculated amount of deviation, the amount of movement of the position of the lens 11 necessary to match the optical axis position of the master image sensor 14M is calculated and obtained. Based on the obtained movement amount, the control device 40 drives the 6-axis actuator 20 to correct the position of the lens 11 (attitude control of the lens unit 13).

  In the next step S26, the position (X coordinate, Y coordinate) of each mark A, B, C, D, E is determined from the information of the image picked up by the master image pickup device 14M in the same manner as the processing performed in step S23. measure.

  In the next step S27, it is determined whether the error (shift amount between the mark position and the reference position) obtained in the same manner as the process performed in step S24 in the control device 40 is very small (YES) or not (NO). To do. If the determination result is YES, the process proceeds to step S31 (end of “posture control of the lens unit 13”), and if the determination result is NO, the process returns to step S24 and the above processing is repeated.

<Assembly of Lens Unit 13 and Imaging Unit 16 ... Steps S31 to S37>
FIG. 6 schematically shows an apparatus configuration when processing relating to the assembly of the lens unit 13 and the imaging unit 16 is performed. In this device configuration, the 6-axis actuator 20 for the lens unit 13 and the 6-axis actuator 25 for the imaging unit 16 are moved from the “adjustment position” to the “assembly position” based on the control from the control device 40. This corresponds to the configuration in which the lens unit 13 and the imaging unit 16 are supported at the assembly position.

  In this apparatus configuration, in the first step S31, the lens unit 13 and the image pickup unit 16 whose postures are controlled at positions where the optical axes are aligned are combined. That is, the actuators 20 and 25 are driven based on the control from the control device 40, and the lens unit 13 and the imaging unit 16 that are fixedly held are moved slightly in the Z-axis direction so as to approach each other.

  At this time, between the end surface of the lens barrel 12 in the lens unit 13 (surface facing the imaging unit 16 side) and the end surface of the holder 15 in the imaging unit 16 (surface facing the lens unit 13 side). An ultraviolet (UV) curable adhesive is allowed to adhere to both sides in an uncured state while ensuring a slight gap.

  In the next step S32, the position of each mark A, B, C, D, E (X coordinate, Y coordinate) from the information of the image captured by the image sensor 14 in the same manner as the processing performed in step S13. Measure.

  In the next step S33, in the same manner as the processing performed in step S14, it is determined in the control device 40 whether the error (shift amount between the mark position and the reference position) is very small (YES) or not (NO). To do. If the determination result is YES, the process proceeds to step S34, and if the determination result is NO, the process proceeds to step S35.

  In step S34, the uncured adhesive interposed between the lens unit 13 and the imaging unit 16 is UV cured, and the units 13 and 16 are fixed (assembled as the camera module 10). Then, this processing flow is “end”.

  On the other hand, in step S35, in the same manner as the processing performed in step S14, the amount of deviation of each mark A, B, C, D, E from the respective reference position (in this case, the position of the image sensor 14). The deviation amount and the positional deviation amount of the lens 11 are calculated. This calculation process is performed using the normalized correlation method as in the above case. The same applies to the recognition of distortion (tilting), expansion / contraction (Z-axis direction), and center deviation (in the XY plane) of the captured image.

  In the next step S36, in the same manner as the processing performed in the above steps S15 and S25, the image sensor 14 or the lens 11 so as to cancel the calculated deviation amount (X, Y, Z, θ, ψ, φ). Correct the position of.

  In the next step S37, the position (X coordinate, Y coordinate) of each mark A, B, C, D, E is measured from the information of the image captured by the image sensor 14 in the same manner as the processing performed in step S32. To do. Then, it returns to step S33 and repeats said process.

  As described above, according to the camera module assembling method (FIG. 3) and the assembling apparatus 50 using the method according to the present embodiment, the chart 30 with alignment marks (FIG. 2) with respect to the assembling imaging unit 16. ) Is captured by the image sensor 14 via the master lens 11M, and the required optical axis position is based on the information (position information of each mark A, B, C, D, E) of the captured image. The posture control of the imaging unit 16 is performed so as to match the above. Similarly, also for the lens unit 13 for assembly, the chart 30 with alignment marks is imaged by the master imaging element 14M via the lens 11, and information of the captured one image (each mark A, B, C) , D and E position information), the attitude of the lens unit 13 is controlled so as to match the required optical axis position.

  As described above, according to the present embodiment, the image pickup by the image pickup device 14 (or the master image pickup device 14M) is performed once for each of the image pickup unit 16 for assembly and the lens unit 13 for assembly. The time required can be shortened. Thereby, it is possible to shorten the time required for combining the lens unit 13 and the imaging unit 16 after the optical axis alignment and completing the assembly as the camera module 10.

  The chart 30 imaged by the image sensor 14 (or the master image sensor 14M) uses a plurality of alignment marks A, B, C, D, and E (FIG. 2) arranged. The normalized correlation method is used when calculating the deviation amount of each mark position from the reference position based on the information of the captured image. Thereby, even if the illumination brightness of the light source 32 for chart imaging changes, it is not affected by the resolution and contrast of the captured image, and the obtained evaluation numerical value does not fluctuate greatly. As a result, it is no longer necessary to make corrections such as management and brightness adjustment to keep the illumination brightness constant, as required in the prior art, and it is possible to simplify illumination brightness management and reduce costs. Can be planned.

10 ... Camera module,
13 (11, 12) ... lens unit (lens, lens barrel),
13M (11M, 12M) ... Master lens unit (master lens, lens barrel),
16 (14, 15) ... imaging unit (imaging device, holder),
16M (14M, 15M) ... Master imaging unit (master imaging device, holder),
20, 25 ... 6-axis actuator (for lens unit, imaging unit),
21 ... Rail,
23, 27 ... posture adjustment mechanism,
24, 28 ... holding part,
30 ... chart with alignment marks,
32 ... light source,
40. Control device,
50. Assembly device,
A, B, C, D, E ... marks for alignment.

Claims (5)

A method of assembling a camera module comprising a lens and a lens unit having a lens barrel for holding the lens, and an image pickup unit having an image pickup element and a holder for holding the image pickup element,
The imaging unit is caused to capture an image of a marked chart in which a plurality of alignment marks illuminated by light from a light source are arranged with the imaging element via a reference lens adjusted to a required optical axis position. After that, based on the mark position information of the captured image, to perform the attitude control of the imaging unit to match the optical axis position,
After causing the lens unit to image the marked chart with the reference image sensor adjusted to the optical axis position through the lens, the optical axis is based on the mark position information of the captured image. Control the posture of the lens unit to match the position,
An assembling method of a camera module, wherein the lens barrel of the lens unit and the holder of the imaging unit, each of which is controlled in posture, are fixed by adhesion.   The posture control of the image pickup unit and the posture control of the lens unit are respectively a process of measuring a plurality of mark positions from information of the picked-up image and a deviation of the measured mark positions from the respective reference positions. The camera module assembling method according to claim 1, further comprising: a process of calculating the amount; and a process of correcting the position of the imaging element or the lens so as to cancel the calculated shift amount.   The camera module assembling method according to claim 2, wherein the process of calculating the deviation amount of each mark position from the reference position is performed using a normalized correlation method.   The process of calculating the amount of deviation of each mark position from the respective reference position is performed by obtaining a relative positional relationship between the respective marks and comparing each obtained value with the reference value, thereby causing distortion, expansion / contraction, or centering of the captured image. The method of assembling a camera module according to claim 3, further comprising a process of detecting a positional shift.   The orientation control of the imaging unit and the orientation control of the lens unit are respectively performed in a Z-axis direction parallel to the optical axis, an X-axis direction and a Y-axis direction orthogonal to each other in a plane orthogonal to the optical axis, and Z 5. The camera module assembling method according to claim 4, wherein the assembling method is performed in at least one of a [theta] direction, a [psi] direction, and a [phi] direction that rotate about an axis, an X axis, and a Y axis, respectively.

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