TWI510077B - Method for adjusting position of image pick-up element, camera module, method and device for fabricating the same - Google Patents

Description

Position adjustment method of camera element, camera module, and manufacturing method and manufacturing device thereof

The present invention relates to a method of adjusting a position of an imaging element with respect to a photographic lens, a camera module having a photographic lens and an imaging element, and a manufacturing method and manufacturing apparatus of the camera module.

In mobile phones, automobiles, etc., in order to easily realize the camera function, a general-purpose camera module is employed. This camera module is constructed by combining a lens unit to which a photographic lens is mounted and an element unit to which an image pickup element such as a CCD or a CMOS is mounted (for example, Japanese Patent Laid-Open Publication No. 2010-21985). The element unit is composed of a substrate, an image pickup element mounted on the substrate, a drive circuit, and the like, and is fixed to the lens unit by an ultraviolet curable resin or the like. In the case where the imaging surface of the imaging element is not parallel to the substrate, or the lens unit is not vertically mounted on the substrate, since the imaging surface of the imaging element is inclined with respect to the imaging surface of the lens unit, the entire screen cannot be changed. Have a bright camera image. Therefore, at the time of manufacture of the camera module, the position adjustment of the element unit with respect to the lens unit is performed so that the imaging surface of the imaging element and the imaging surface of the lens unit substantially coincide with each other.

The position adjustment method of the imaging element described in Japanese Laid-Open Patent Publication No. 2010-21985 includes a focus coordinate value acquisition step, an imaging surface calculation step, an adjustment value calculation step, and an adjustment step. The focus coordinate value acquisition step sets the lens unit and the element unit on the Z axis perpendicular to the measurement chart, and causes the element unit to sequentially move toward a plurality of measurement positions set in advance on the Z axis in advance, and to perform imaging. Then, the focus evaluation value indicating the degree of focus of each imaging region is calculated from the imaging signals of the central imaging unit set on the imaging surface of the imaging element and the five imaging regions around it. The in-focus evaluation value of each imaging area is calculated for each measurement position. Then, when a predetermined in-focus evaluation value has been obtained for each imaging region, the position on the Z-axis is taken as the focus coordinate value of the region.

In the imaging plane calculation step, at least five evaluation points indicated by a combination of the XY coordinate value of each imaging region and the focus coordinate value on the Z axis are used, and the XY coordinate values of the imaging regions are such that the imaging surface corresponds to The XY coordinate value of each imaging region when the XY coordinate plane perpendicular to the Z axis corresponds, and the focus coordinate value on the Z axis is obtained for each region of each imaging region. When the five evaluation points are plotted on the three-dimensional coordinate system in which the XY coordinate plane and the Z-axis are combined, an approximate imaging surface which is represented as a plane in the three-dimensional coordinate system is calculated. Actually, the evaluation point is calculated by the least square method, and the approximating plane is used as an approximate imaging plane (refer to [0065] and [0079] of JP-A-2010-21985).

The adjustment value calculation step calculates the coordinate value of the imaging plane as the intersection of the Z-axis and the approximate imaging plane, and the rotation angle around the X-axis and the Y-axis of the approximate imaging plane of the XY coordinate plane. The adjustment step adjusts the position of the imaging element on the Z axis and the rotation angle around the X axis and the Y axis according to the coordinate value of the imaging surface and the rotation angle, so that the imaging surface is aligned with the approximate imaging surface.

In recent years, camera modules have become smaller and lighter, and it is expected that the substrate of the element unit can be made thinner. However, when the thickness of the substrate is thin, For example, in a substrate or the like on which a multilayer film is formed by sputtering or the like, there is a problem that the substrate is subjected to bending deformation due to film stress (compression stress) of the multilayer film.

The method of calculating the approximate imaging surface by the least squares method described in Japanese Laid-Open Patent Publication No. 2010-21985 is a state in which the imaging surface of the imaging element is tilted in the same state and is tilted in the same position at the full evaluation point. The approximated image plane calculated is the surface that has been corrected to be inclined (vertical surface). Further, when the imaging surface is completely deformed in a wave shape and the relative position of the full evaluation point includes a certain error, the approximated imaging surface to be calculated also becomes a surface including a certain error. Therefore, in the case where the substrate is deformed in the same state, there is no problem even in the method of the prior art.

However, in the case where the substrate is locally deformed, it becomes impossible to obtain an approximate image plane in which the deformation has been corrected. For example, as shown in Fig. 26A, one portion 200a of the imaging surface 200 is deformed. In this case, a part of the in-focus evaluation value 201 at a position where the degree of focusing is high includes an abnormal value 201a. In the case where the least square method is used for the objective function, the abnormal value 201a is not reflected on the approximate imaging plane 202, so that the resolution of one portion 200a of the imaging surface 200 is extremely lowered. Further, in Fig. 26A, the horizontal direction is the Z-axis direction, and the vertical direction is the Y-axis direction, and the in-focus evaluation value in the assumed space is expressed by the direction in which the direction is reversed from the direction in which the substrate is deformed.

The object of the present invention is to solve the resolution by local deformation of the substrate. The imaging element that is unevenly adjusted can adjust the resolution of the entire imaging surface with a good balance.

In order to solve the above problems, the method for adjusting the position of the imaging device of the present invention and the method for manufacturing the camera module include an imaging step, a focus coordinate value acquisition step, an interpolation step, a Z-axis coordinate value acquisition step, an approximate plane calculation step, The resolution acquisition step, the specific imaging plane decision step, and the adjustment step are estimated.

The imaging step is performed by moving either one of the photographic lens or the imaging element toward each measurement coordinate value (each measurement position on the Z axis) along the Z axis perpendicular to the measurement chart, and at each measurement coordinate The measurement chart is taken with the imaging element. The focus coordinate value obtaining step calculates the degree of focus indicating the respective imaging regions based on the imaging signals obtained from a plurality of imaging regions set on the imaging surface of the imaging device, for example, the central portion and two or more peripheral portions. Individual focus evaluation values. This focus evaluation value is calculated for each measurement coordinate value. The interpolation step interpolates the in-focus evaluation value of each measurement coordinate value on the Z-axis in each of the imaging regions, and calculates the continuous focus evaluation value data. The Z-axis coordinate value obtaining step is to obtain a Z-axis coordinate value of the peak value of the continuous focus evaluation value data of the imaging region set in the center of the imaging surface. The approximate plane calculation step is to draw at least three or more evaluation points on a three-dimensional coordinate system in which the XY coordinate plane and the Z-axis are combined, and the at least three evaluation points are such that the imaging surface is perpendicular to the Z A combination of the XY coordinate axes of the respective imaging regions when the XY coordinate plane of the axis corresponds, and the measured coordinate values on the Z axis. Based on the relative positions of the evaluation points, an approximate plane which is represented as a plane in the three-dimensional coordinate system is calculated. The estimated resolution obtaining step first moves the approximate plane such that the intersection of the approximate plane and the Z-axis becomes the Z-axis coordinate value. The estimated resolution of each imaging region in each imaging plane is obtained from the intersection of a plurality of imaging planes that are movable around the X and Y axes around the movement position and the successive focus evaluation data. The particular imaging plane decision step determines a particular imaging plane based on a balance evaluation value representative of the deviation of the estimated resolution. The adjusting step calculates an imaging surface coordinate value which is an intersection of the Z axis and the specific imaging plane, and a rotation angle about the X axis and the Y axis with respect to the specific imaging plane of the XY coordinate plane, so that the imaging surface is This particular imaging plane is consistent. The method of manufacturing the camera module further includes the step of fixing the lens unit to the component unit in a state where the position of the imaging element has been adjusted for the photographic lens.

The specific imaging plane determining step includes: a step of calculating a resolution change rate per unit length in the Z-axis direction for each of the continuous focus evaluation data; and determining a range in which the resolution change rate is small as a search range, The step of determining the particular imaging plane within this search range is preferred. It is preferable to adhere the lens unit to the element unit by the fixing step with an ultraviolet curing adhesive.

The camera module manufacturing apparatus of the present invention includes: a measurement chart, a lens unit holding unit, an element unit holding unit, a measurement position moving unit, an imaging element control unit, a focus coordinate value acquisition unit, an interpolation unit, and a Z-axis coordinate value acquisition. Part, approximate plane calculation unit, estimated resolution acquisition unit, specific imaging plane determination unit, adjustment unit, and fixed unit.

A measurement pattern is formed on the measurement chart. The lens unit holding unit holds and sets the lens unit on which the photographic lens is mounted on the Z axis perpendicular to the measurement chart. The element unit holding unit holds and sets the element unit on which the image pickup element is mounted on the Z axis, and changes the position on the Z axis of the element unit and the X axis and the Y axis perpendicular to the Z axis. . The measurement position moving unit moves one of the lens unit holding unit or the element unit holding unit to each measurement coordinate value set in advance on the Z axis in advance. The imaging element control unit is configured to capture a chart image on each value of the measurement coordinate value on the Z axis. The focus coordinate value acquisition unit sets a central portion and two or more peripheral portions set on the imaging surface of the imaging element as an imaging region, and measures the coordinate value for each of the Z-axis based on the imaging signals obtained from the regions. An individual focus evaluation value indicating the degree of focus in each imaging area is calculated. The interpolation unit interpolates the in-focus evaluation value of each measurement coordinate value on the Z axis in each of the imaging regions, and calculates the continuous focus evaluation value data. The Z-axis coordinate value acquisition unit obtains a Z-axis coordinate value of a peak value of the continuous focus evaluation value data set in the imaging region at the center of the imaging surface. The approximate plane calculation unit uses at least three or more evaluation points, and the at least three or more evaluation points are XY coordinate axes of the imaging regions when the imaging surface corresponds to the XY coordinate plane perpendicular to the Z axis, and A combination of measured coordinate values on the Z axis is represented. When at least three or more evaluation points are drawn on a three-dimensional coordinate system in which the XY coordinate plane and the Z-axis are combined, the relative position of the evaluation points is calculated and expressed as a plane in the three-dimensional coordinate system. Approximate plane. The estimated resolution acquisition unit moves the approximate plane such that the intersection of the approximate plane and the Z-axis becomes the Z-axis coordinate value. The estimated resolution of each imaging region in each imaging plane is obtained from the intersection of a plurality of imaging planes that are movable about the X and Y axes around the position and the successive focus evaluation data. The specific imaging plane determining unit determines a specific imaging plane based on a balance evaluation value indicating a deviation of the estimated resolution. The adjustment unit calculates an imaging surface coordinate value which is an intersection of the Z axis and the specific imaging plane, and a rotation angle about the X axis and the Y axis with respect to the specific imaging plane of the XY coordinate plane, so that the imaging surface is This particular imaging plane is consistent. The fixing portion fixes the lens unit and the element unit in a state where the position of the image pickup element has been adjusted with respect to the photographic lens.

The specific imaging plane determining unit calculates a resolution change rate per unit length in the Z-axis direction of each of the continuous focus evaluation data, and determines a range in which the resolution change rate is small as a search range, and the search range is It is appropriate to determine this particular imaging plane. The camera module of the present invention is manufactured by a manufacturing method of a camera module.

The imaging area may be a central portion and two or more peripheral portions, and a central portion and four or more peripheral portions are more preferable. As a method of determining the specific imaging plane, the imaging plane can be determined such that the balance evaluation value satisfies a predetermined specification value, and the imaging plane can be determined such that the balance evaluation value is minimized.

For each imaging area, the position on the Z-axis where the focus evaluation value becomes the largest measurement coordinate value is used as the focus coordinate value. Thereby, the position of the imaging element can be adjusted based on the position on the Z axis where the focus evaluation value becomes the highest.

In addition, in the acquisition of the focus coordinate value, each focus evaluation value calculated by each value of the plurality of measurement coordinate values may be sequentially compared between the measurement positions adjacent to each other in the Z-axis direction. When the focus evaluation value is continuously decreased by a predetermined number of times, the movement of the photographic lens or the imaging element toward the measurement coordinate value is suspended. In this case, the measurement position (the coordinate value on the Z axis) before the focus evaluation value is lowered can be used as the focus coordinate value. Thereby, it is not necessary to obtain the in-focus evaluation value at all measurement coordinate values, so the time required to obtain the focus coordinate value can be shortened.

Further, in the acquisition of the other focus coordinate values, an approximate curve may be generated from the plurality of evaluation points for each imaging region, and the position on the Z-axis corresponding to the maximum focus evaluation value obtained from the approximate curve may be used as the focus. The coordinate value, the plurality of evaluation points are represented by a combination of a plurality of measurement coordinate values and respective in-focus evaluation values corresponding to the plurality of measurement coordinate values. Thereby, it is not necessary to actually measure the maximum value of the in-focus evaluation value of each imaging area, so that the time can be shortened compared with the case where the maximum value is actually measured. In addition, according to the maximum value of the focus evaluation value, the focus coordinate value can be obtained, so the adjustment accuracy can be improved.

Further, in the acquisition of the other focus coordinate values, the difference between the predetermined designated value and each focus evaluation value calculated for each of the plurality of measurement coordinate values may be calculated for each imaging region, and the difference may be calculated. The coordinate value on the Z axis of the smallest measurement position is used as the focus coordinate value. As a result, the in-focus evaluation values of the respective imaging regions can be agreed in a good balance with all aspects, so that the picture quality can be improved.

As the in-focus evaluation value, it is preferable to use the contrast transfer function value. Further, in the acquisition of the focus coordinate value, the first direction set on the XY coordinate plane and the second direction perpendicular to the first direction may be calculated for each of the plurality of measurement positions for each imaging region. The contrast transfer function value in the direction is obtained, and for each of the imaging regions, the respective first focus coordinate value and second focus coordinate value are obtained in each of the first direction and the second direction. In the determination of the specific imaging plane, it is preferable to obtain an evaluation point of at least 10 points from the first focus coordinate value and the second focus coordinate value of each imaging region, and to calculate an approximate plane based on the relative positions of the evaluation points. Thereby, in each imaging region, even if the values of the contrast transfer function in the plurality of directions have deviations, an approximate plane with good balance can be obtained. In addition, by increasing the evaluation point, the calculation accuracy of the approximate plane can be improved.

As the first direction and the second direction for calculating the value of the contrast transfer function, it is preferable to use the horizontal direction and the vertical direction. Alternatively, the value of the contrast transfer function can be obtained in the radial direction of the photographic lens and in the vertical direction perpendicular to the radial direction.

It is preferable to set at least three imaging areas set on the imaging surface, for example, two on the diagonal line set in the center of the imaging surface and the four quadrants of the imaging surface. In the case where five imaging areas are provided, it is preferable to set one of each of the four quadrants set to the center of the imaging surface and the imaging surface. Further, in the acquisition of the focus coordinate value, it is preferable to form the same map pattern for each imaging region.

After adjusting the position, the focus coordinate value can be obtained again, and the focus coordinate value can be confirmed for each imaging area. In addition, the focus coordinate value acquisition step, the interpolation step, the specific imaging plane determination step, and the adjustment step may be performed repeatedly to make the imaging surface coincide with the specific imaging plane. Thereby, the adjustment accuracy can be improved.

The element unit holding portion is constituted by a holding mechanism that holds the element unit, a two-axis rotating table that tilts the holding mechanism about the X-axis and the Y-axis, and a slide table that moves the two-axis rotating table in the Z-axis direction. The element unit holding portion may be provided with an element connection portion electrically connected to the image pickup element and the element control portion. In addition, an AF connecting portion that electrically connects the auto focus mechanism in the mounted lens unit and the AF driver that drives the auto focus mechanism may be disposed in the lens unit holding portion.

The chart pattern has eight regions in which the surface of the rectangle is divided in the X-axis direction, the Y-axis direction, and the two diagonal directions with respect to the center position, and is disposed in two regions of the first to fourth quadrants, respectively. Set a plurality of parallel lines perpendicular to each other. Thereby, there is no need to exchange measurement charts, and it is also applicable to the manufacture of camera modules using image elements of different angles.

The component unit used in the camera module of the present invention is positionally adjusted in the following order. First, the lens unit and the element unit are set on the Z axis perpendicular to the measurement chart, and either the photographic lens or the imaging element is sequentially moved toward the measurement coordinate value (measurement position) on the Z axis to measure the coarse coordinate value. Take a measurement chart. The individual focus evaluation value indicating the degree of focus in each imaging area is calculated for each of the measurement coordinate values on the Z-axis from the imaging signal obtained from the imaging area set on the imaging surface of the imaging element and the four peripheral portions. . The in-focus evaluation value of each measurement coordinate value on the Z axis in each imaging area is interpolated, and the continuous focus evaluation value data is calculated.

Next, the Z-axis coordinate value of the peak value of the continuous focus evaluation value data of the imaging area set in the center of the imaging surface is obtained. When at least five evaluation points are developed on a three-dimensional coordinate system in which the XY coordinate plane and the Z-axis are combined, the approximate plane represented as a plane in the three-dimensional coordinate system is calculated based on the relative positions of the evaluation points, and The at least five evaluation points are represented by a combination of the XY coordinate axes of the respective imaging regions when the imaging surface corresponds to the XY coordinate plane perpendicular to the Z axis, and the measured coordinate values on the Z axis. Moving the approximate plane in such a manner that the intersection of the approximate plane and the Z-axis becomes the Z-axis coordinate value, and the intersection of the plurality of imaging planes that can move around the X and Y axes with the continuous focus evaluation data according to the position. The estimated resolution of each imaging region in each imaging plane is obtained. The specific imaging plane is determined based on the balance evaluation value indicating the deviation of the estimated resolution of each imaging region from each imaging plane. The image plane coordinate value as the intersection of the Z axis and the specific imaging plane, and the rotation angle around the X axis and the Y axis for a specific imaging plane of the XY coordinate plane are calculated. The position of the imaging element on the Z-axis and the tilt around the X-axis and the Y-axis are adjusted so that the imaging surface coincides with the specific imaging plane.

In the present invention, the imaging plane obtained by moving the approximate plane is obtained for each imaging region, and an estimated evaluation value indicating the deviation of the estimated resolution is calculated from the estimated resolution. According to this balance evaluation value from Since a specific imaging plane is determined in each imaging plane, even if there is a portion having a very low resolution in a portion of the imaging surface by deformation or the like of the substrate on which the imaging element is mounted, the resolution of the reduced portion can be improved. The imaging surface can be adjusted to a well-balanced resolution.

In the first and second figures, the camera module 2 is designed to have, for example, a box shape having a size of about 10 mm on one side. A photographing opening 5 is formed in the center of the front surface of the camera module 2. A photographic lens 6 is disposed deep in the photographic opening 5. A positioning recess for positioning the camera module 2 during manufacture is provided at a corner of the front surface of the camera module 2. In the present embodiment, the positioning recesses 7 to 9 are provided at the three corner portions. Positioning holes 7a, 9a are formed in substantially the center of the two positioning recesses 7, 9 located on one diagonal line. Thereby, the absolute position and inclination in space are restricted with high precision.

A rectangular opening 11 is formed on the back surface of the camera module 2. The opening 11 is for exposing a plurality of contacts 13 provided on the back surface of the imaging element 12 built in the camera module 2.

As shown in FIG. 3, the camera module 2 is composed of a lens unit 15 to which the imaging lens 6 is mounted and an element unit 16 to which the imaging element 12 is mounted. The element unit 16 is attached to the back side of the lens unit 15.

As shown in Fig. 4, the lens unit 15 is composed of a unit body 19 designed in a rectangular tube shape, a lens barrel 20 mounted in the unit body 19, and a front cover 21 fixed to the front side of the unit body 19. The front cover 21 is provided with a photographing opening 5, positioning recesses 7 to 9, and the like. The unit body 19, the lens barrel 20, and the front cover 21 are formed of, for example, plastic.

The lens barrel 20 is designed in a cylindrical shape, and for example, three groups of photographic lenses 6 are mounted inside. The lens barrel 20 is held by a metal spring 24 attached to the front surface of the unit body 19, and is formed to be freely movable in the direction of the optical axis S by the elasticity of the spring 24.

A permanent magnet 25 and an electromagnet 26 are attached to the outer circumference of the lens barrel 20 and the inner circumference of the unit body 19 so as to achieve an autofocus function. The electromagnet 26 changes the polarity by switching the direction of the supplied current. The lens barrel 20 is repelled or attracted by the permanent magnet 25 in response to a change in polarity of the electromagnet 26, and is moved in the direction of the optical axis S to adjust the focus. The current is supplied to the contact 26a of the electromagnet 26 so as to be exposed from the lower surface of the unit body 19. Further, as a drive mechanism for moving the lens barrel 20 for the autofocus function, a pulse motor + a feed screw, a piezoelectric vibrator + an inertial mechanism, or the like is used.

The element unit 16 is composed of an element frame 29 formed in a rectangular frame shape and an imaging element 12 mounted in the element frame 29 such that the imaging surface 12a faces the lens unit 15 side. The component frame 29 is formed of, for example, plastic.

Four fitting pieces 32 and concave fitting grooves 33 into which the fitting pieces 32 are fitted are provided at the front side surface of the element frame 29 and the corner between the side surface and the back surface of the unit main body 19. After the fitting piece 32 is fitted to the fitting groove 33, the lens unit 15 and the element unit 16 are adhered by injecting an adhesive into the fitting groove 33.

A pair of notches 36 are provided on the back surface of the unit body 19. As is apparent from Fig. 7, the positions of the notches 36 in the Y direction are different. Further, a pair of concave portions 37 are provided on both side faces of the element frame 29. The notch 36 and the recess 37 are used to position and hold both of the lens unit 15 and the element unit 16 when assembled. The unit body 19 and the element frame 29 are formed by injection molding, and the side surface is designed to have a flat taper for the purpose of demolding. Here, in order to ensure planarity, a notch 36 and a recess 37 are provided. Therefore, in the case of maintaining the surface having no taper at the time of assembly, the notch 36 and the recessed portion 37 may not be provided.

Next, the configuration of the camera module manufacturing apparatus will be described with reference to Fig. 5 . The camera module manufacturing device 40 is for adjusting the position of the component unit 16 with respect to the lens unit 15. After the position is adjusted, the component unit 16 is fixed to the lens unit 15 with an adhesive to complete the camera module. The camera module manufacturing apparatus 40 is controlled by, for example, a chart unit 41, a condensing unit 42, a lens positioning plate 43, a lens holding mechanism 44, a component moving mechanism 45, an adhesive supplier 46, an ultraviolet lamp 47, and control of these components. The department 48 is composed of. These components are disposed on a common work surface 49.

The chart unit 41 is composed of a chart box 41a, a measurement chart 52 housed in the chart box 41a, and a light source 53. The measurement chart 52 is, for example, a translucent plastic plate, and a plastic plate designed to be milky white is suitable. This measurement chart 52 is illuminated from the back side by parallel illumination light from source 53.

As shown in Fig. 6, the measurement chart 52 is designed in a square shape, and a chart pattern is printed on the surface (the surface of the figure). The chart pattern has the first to fifth chart images 56 to 60 at the center 52a and the upper, lower left, upper right, and lower right. The first to fifth chart images 56 to 60 are all the same image, and are rudder-like charts in which black lines are arranged at predetermined intervals, and the images are horizontal chart images 56a arranged in the horizontal direction. ～60a and vertical chart images 56b to 60b arranged in the vertical direction.

The condensing unit 42 is disposed on the Z axis perpendicular to the center 52a of the measurement chart 52 so as to face the chart unit 41. The condensing unit 42 is composed of a holder 42a and a condensing lens 42b that are fixed to the work table 49. The condensing lens 42b condenses the light emitted from the chart unit 41, and enters the lens unit 15 through the opening 42c formed in the holder 42a.

The lens positioning plate 43 is made of, for example, metal in order to obtain rigidity, and is provided with an opening 43a through which light collected by the condensing unit 42 passes.

As shown in Fig. 7, on one surface of the lens positioning plate 43, that is, the surface facing the lens holding mechanism 44, three abutting pins 63 to 65 are provided around the opening 43a. Among the three abutting pins 63 to 65, the front end of the two abutting pins 63, 65 disposed on the diagonal line are provided with small-diameter insertion pins 63a, 65a. When the abutment pins 63 to 65 enter the positioning recesses 7 to 9 of the lens unit 15, the insertion pins 63a, 65a are inserted into the positioning holes 7a, 9a, and the lens unit 15 is positioned.

The lens holding mechanism 44 is constituted by a holding plate 68 that holds the lens unit 15 so as to face the chart unit 41 on the Z axis, and a first slide table 69 that moves the holding plate 68 in the Z-axis direction. As shown in Fig. 7, the holding plate 68 includes a horizontal base portion 68a that is held by the table portion 69a of the first slide table 69, and a pair of holding arms 68b that are protruded upward and horizontally from the horizontal base portion 68a. It is incorporated in one of the pair of lens units 15 in the notch 36.

A first probe unit 70 having a plurality of probes 70a that are in contact with the contact 26a of the electromagnet 26 is attached to the holding plate 68. The first probe unit 70 is for electrically connecting the electromagnet 26 and the AF driver 84 (see Fig. 8).

The first slide table 69 is called a so-called automatic precision stage, and the ball screw is rotated by the rotation of a motor (not shown) to horizontally move the table portion 69a that meshes with the ball screw.

The component moving mechanism 45 is composed of a chuck hand 72, a two-axis rotating table 74, and a second sliding table 76. The chuck 72 is attached to the Z-axis to hold the component unit 16 such that the imaging surface 12a faces the chart unit 41. The 2-axis rotary table 74 holds a crank-shaped bracket 73 on which the chuck 72 is mounted, and is wound around two axes perpendicular to the Z-axis. To adjust the tilt. The second slide table 76 holds the holder 75 to which the two-axis rotary table 74 is attached, and moves the holder in the Z-axis direction.

As shown in Fig. 7, the chuck 72 is composed of one of the gripping members 72a bent in a crank shape and an actuator 72b that moves the gripping members 72a in the X-axis direction perpendicular to the Z-axis. The holding member 72a holds the component unit 16 into the recess 37 of the component frame 29 to hold the component unit 16. Further, the chuck 72 positions the component unit 16 held by the holding member 72a so that the optical axis center of the imaging lens 6 substantially coincides with the center 12b of the imaging surface 12a.

The two-axis rotating table 74 is referred to as a so-called automatic two-axis horn, and the element unit 16 is oriented in the θ direction around the X-axis centering on the center 12b of the imaging surface 12a by rotation of two motors (not shown). And tilting in the Φ direction about the Y axis perpendicular to the Z axis and the X axis. Thereby, when the element unit 16 is tilted in each direction, there is no offset in the positional relationship between the center 12b of the imaging surface 12a and the Z axis.

The second stage 76 is configured to move the measurement position (measurement coordinate value), and the element unit 16 is moved in the Z-axis direction via the two-axis rotary table 74. Further, the second slide table 76 has the same structure as the first slide table 69 in terms of size and the like, and the detailed description thereof is omitted.

A second probe unit 79 for electrically connecting the imaging element 12 and the imaging element driver 85 (see FIG. 8) is mounted on the two-axis rotating table 74. The second probe unit 79 has a plurality of probes 79a that are in contact with the respective contacts 13 of the imaging element 12 through the opening 11 of the element unit 16.

When the position adjustment of the adhesive unit 46 is completed in the element unit 16, and the fitting piece 32 of the element unit 16 is fitted to the fitting portion 33 of the lens unit 15, the ultraviolet curing adhesive is supplied into the fitting portion 33. The ultraviolet lamp 47 is irradiated with ultraviolet rays toward the fitting portion 33 to cure the ultraviolet curable adhesive. In the present embodiment, the lens unit 15 and the element unit 16 are fixed by the adhesive supplier 46 and the ultraviolet lamp 47. Further, as the adhesive, an instant adhesive, a heat-curing adhesive, a natural hardening adhesive, or the like can be used.

In Fig. 8, the control unit 48 includes a microcomputer such as a CPU, a ROM, and a RAM, and controls each unit based on a control program stored in the ROM. Further, the control unit 48 is connected to an input device 81 such as a keyboard or a mouse for performing various settings, and a monitor 82 for displaying setting contents, work contents, work results, and the like.

The AF driver 84 drives a drive circuit of the electromagnet 26, and supplies current to the electromagnet 26 via the first probe unit 70. The imaging element driver 85 drives a driving circuit of the imaging element 12, and inputs a control signal to the imaging element 12 via the second probe unit 79.

The focus coordinate value acquisition circuit 87 obtains a focus at a position where the focus is high in the Z-axis direction of the first to fifth imaging regions 89a to 89e set on the imaging surface 12a of the imaging device 12 shown in Fig. 9 . Coordinate value. The first to fifth imaging regions 89a to 89e are set at the center 12b and the upper left, lower left, upper right, and lower right of the imaging surface 12a, and the first to fifth chart images 56 to 60 of the measurement chart 52 can be captured. Further, since the measurement chart 52 is imaged upside down and left and right by the imaging lens 6, the second to fifth imaging regions 89b to 89e are respectively arranged on the second to fifth graphs arranged on the opposite side of the diagonal line. Shoot like 57~60.

When the focus coordinate values of the first to fifth imaging regions 89a to 89e are obtained, the control unit 48 controls the second slider 76 to sequentially move the component unit 16 to a plurality of measurement positions that are previously dispersedly set on the Z axis. . Moreover, the control unit 48 controls the image sensor driver 85 to cause the image pickup device 12 to capture the image images of the first to fifth chart images 56 to 60 imaged by the image pickup lens 6 at the respective measurement positions.

The focus coordinate value acquisition circuit 87 first extracts signals of pixels corresponding to the first to fifth imaging regions 89a to 89e from the imaging signals input via the second probe unit 79. Then, the in-focus evaluation values for the respective first to fifth imaging regions 89a to 89e are calculated from the pixel signals. This focus evaluation value is calculated for each measurement position. When the in-focus evaluation value within the predetermined range is obtained for each of the first to fifth imaging regions 89a to 89e, the measurement position is taken as the measurement coordinate value on the Z-axis.

In the present embodiment, a contrast transfer function value (hereinafter referred to as a CTF value) is used as the in-focus evaluation value. The CTF value indicates the value of the contrast with respect to the image of the spatial frequency, and when the CTF value is high, it can be considered to be in focus. The CTF value is obtained by dividing the sum of the maximum value and the minimum value of the output values by the difference between the maximum value and the minimum value of the output values of the image pickup signals output from the image pickup device 12. For example, when the maximum value of the output value of the image pickup signal is P and the minimum value is Q, the CTF value is calculated based on the following equation (1).

CTF value=(PQ)/(P+Q) (1) The focus coordinate value acquisition circuit 87 is configured to set a plurality of imaging regions of the first to fifth imaging regions 89a to 89e on the Z axis. The measurement position is calculated for each direction of the plurality of directions set on the XY coordinate plane. The direction in which the CTF value is calculated is an arbitrary first direction and a second direction perpendicular to the first direction. In the present embodiment, the CTF values (H-CTF value and V-CTF value) in the horizontal direction (X-axis direction), that is, the lateral direction of the imaging surface 12a and the vertical direction (Y-axis direction) perpendicular to the direction are calculated. . In addition, the focus coordinate value acquisition circuit 87 acquires the coordinates on the Z-axis of the measurement position where the H-CTF value and the V-CTF value become the maximum for each of the first to fifth imaging regions 89a to 89e as the horizontal focus. Coordinate value and vertical focus coordinate value.

The horizontal focus coordinate value and the vertical focus coordinate value of the first to fifth imaging regions 89a to 89e are input from the focus coordinate value obtaining circuit 87 to the interpolation circuit 92. The interpolation circuit 92 interpolates the in-focus evaluation value of each measurement coordinate value on the Z axis of each of the imaging regions 89a to 89e, and calculates the continuous focus evaluation value data. By calculating the continuous focus evaluation value data by the interpolation circuit 92, for example, the focus evaluation value of each measurement coordinate value on the Z axis among the imaging regions 89a to 89e is interpolated, and the continuous focus evaluation value data is calculated. . Further, the interpolation circuit 92 is not limited to the spline interpolation, and can be interpolated by well-known cubic interpolation, Lagrangian interpolation, and most recent interpolation.

The continuous imaging evaluation value data of each of the imaging regions 89a to 89e is input to the specific imaging plane determining circuit 93. The specific imaging plane determining circuit 93 obtains the Z-axis coordinate value of the peak value of the continuous focus evaluation value data set in the imaging region 89a at the center of the imaging surface 12a. At least five evaluation points are used, and the XY coordinate axes of the imaging regions 89a to 89e when the imaging surface 12a corresponds to the XY coordinate plane perpendicular to the Z axis, and the measurement on the Z axis are used. A combination of coordinate values is represented. When the five evaluation points are plotted on the three-dimensional coordinate system composed of the X-axis, the Y-axis, and the Z-axis, the approximate plane represented as a plane in the three-dimensional coordinate system is calculated based on the relative positions of the evaluation points.

The calculation of the approximate imaging plane by the specific imaging plane determining circuit 93 is, for example, a least squares method expressed by a formula (a to d is an arbitrary constant) of aX+bY+cZ+d=0. The specific imaging plane determining circuit 93 is a coordinate value on the XY coordinate plane of the first to fifth imaging regions 89a to 89e and a horizontal focus coordinate value obtained on the Z-axis obtained by the focus coordinate value obtaining circuit 87. Or the vertical focus coordinate value is substituted into the above equation to calculate the approximate imaging surface.

The specific imaging plane determining circuit 93 arranges the calculated approximate plane on the hypothetical three-dimensional model, and moves the approximation toward the Z-axis coordinate value such that the intersection of the approximate plane and the Z-axis becomes the Z-axis coordinate value, that is, the peak value of the continuous focus evaluation data. flat. Then, based on the intersection of the imaging region of the plurality of imaging planes that can be moved around the X and Y axes around the position and the continuous focus evaluation data, the estimation analysis of each of the imaging regions 89a to 89e in each imaging plane is obtained. degree. Further, there is a fear that the imaging areas 89a to 89e of the respective imaging planes deviate from the respective continuous focus evaluation data. In this case, therefore, the deviation is extremely small, so that it is judged to be within the error range, and the approximated in-focus evaluation value is taken as the estimated resolution.

At this time, the specific imaging plane determining circuit 93 calculates the resolution change rate per unit length in the Z-axis direction for each continuous focus evaluation data, and determines the range in which the resolution change rate is small as the search range to be within the search range. The way determines the specific imaging plane. Further, as a parameter for determining the search range, in addition to the range in which the resolution is less reduced, the search range can be determined in consideration of the predicted change amount of the imaging surface generated after the adhesion and the predetermined resolution allowable value. In this case, for example, it is judged whether or not the estimated resolution of each of the imaging regions 89a to 89e on each imaging plane falls within each search range. In the case of completely falling within each search range, the estimated resolution of each of the imaging regions 89a to 89e in each imaging plane is obtained. When it is not in each search range, for example, parameter change such as making the resolution allowable value loose is performed to expand each search range, and it is determined again whether each imaging plane falls within each search range. Here, the predicted change amount of the imaging surface 12a after adhesion is determined based on the data actually measured in advance.

After determining that each imaging plane falls within each search range, the specific imaging plane determining circuit 93 determines, from each imaging plane, a specific imaging plane in which the deviation of the average value of the estimated resolutions of each of the imaging regions 89a to 89e becomes the smallest. The deviation of the average value of the estimated resolution (hereinafter referred to as [balance evaluation value]) is obtained by the following formula (2). As a method of determining the specific imaging plane, the estimated resolution of each of the imaging regions 89a to 89e in each imaging plane is substituted into the equation (2) to calculate a balance evaluation value, and the imaging plane in which the balance evaluation value is the smallest is determined. Further, an imaging plane that satisfies the specification value in which the balance evaluation value is determined in advance may be determined as a specific imaging plane.

Here, n denotes the number of the imaging region shown in FIG. 9, R _n denotes an estimated resolution in the imaging region n, Rh denotes an estimated resolution average value, and B denotes a balanced evaluation value of the estimated resolution.

The information of the specific imaging plane is input from the specific imaging plane decision circuit 93 toward the adjustment value operation circuit 95. The adjustment value calculation circuit 95 calculates an imaging surface coordinate value on the Z-axis which is the intersection of the Z-axis and the specific imaging plane, and an X-axis and a Y-axis rotation, that is, an XY-direction rotation, for a specific imaging plane of the XY coordinate plane. The angle is input to the control unit 48. The control unit 48 drives the element moving mechanism 45 based on the imaging surface coordinate value and the XY direction rotation angle input from the adjustment value calculation circuit 95, and adjusts the position and posture of the element unit 16 so that the imaging surface 12a coincides with the specific imaging plane.

Next, the action of the above embodiment will be described with reference to the flowcharts of Figs. 10 to 12. First, the holding of the lens unit 15 by the lens holding mechanism 44 will be described (S1). The control unit 48 controls the first slide table 69 to move the holding plate 68, whereby a space into which the lens unit 15 can be inserted is formed between the lens positioning plate 43 and the holding plate 68. The lens unit 15 is held by a robot (not shown) and moves between the lens positioning plate 43 and the holding plate 68.

The control unit 48 detects the movement of the lens unit 15 by an optical sensor or the like, and moves the table portion 69a of the first stage 69 in a direction close to the lens positioning plate 43. The holding plate 68 engages the pair of holding arms 68b in the pair of notches 36 to maintain the lens unit 15. The first probe unit 70 is in electrical contact with the AF driver 84 by contacting the contact 26a.

After the holding of the lens unit 15 by the robot (not shown) is released, the holding plate 68 is further moved in the direction of the lens positioning plate 43. By the movement of the holding plate 68, the positioning recesses 7 to 9 abut against the abutment pins 63 to 65, and the insertion pins 63a, 65a are inserted into the positioning holes 7a, 9a. Thereby, the lens unit 15 is positioned in the Z-axis direction, the X-axis direction, and the Y-axis direction. Further, only three positioning recesses 7 to 9 and the contact pins 63 to 65 are provided, and the positioning holes 7a and 9a and the insertion pins 63a and 65a are provided on only two diagonal lines. Therefore, the lens unit 15 does not have The case where the wrong posture is set.

Next, the holding of the component unit 16 by the component moving mechanism 45 will be described (S2). The control unit 48 controls the second slide table 76 to move the two-axis rotary table 74, thereby forming a space in which the component unit 16 can be inserted between the holding plate 68 and the two-axis rotary table 74. The component unit 16 is held by a robot (not shown) and moves between the holding plate 68 and the two-axis rotating table 74.

The control unit 48 detects the movement of the element unit 16 by an optical sensor or the like, and moves the table portion 76a of the second stage 76 in a direction close to the holding plate 68. Then, the component unit 16 is sandwiched into the recess 37 by the holding member 72a of the chuck 72 to hold the component unit 16. Further, each of the probes 79a of the second probe unit 79 is in contact with each of the contacts 13 of the imaging element 12 to electrically connect the imaging element 12 and the control unit 48. Then, the holding of the component unit 16 by the robot (not shown) is released.

After the holding of the lens unit 15 and the element unit 16, the horizontal focus coordinate value and the vertical focus coordinate value of the first to fifth imaging regions 89a to 89e of the imaging surface 12a are obtained (S3). This step (S3) is composed of the following steps S3-1 to S3-6 shown in Fig. 11. First, the control unit 48 controls the second slide table 76 to move the two-axis rotary table 74 in the direction close to the lens holding mechanism 44, and moves the element unit 16 to the first measurement position of the image pickup device 12 closest to the lens unit 15 ( S3-1).

The control unit 48 causes the light source 53 of the chart unit 41 to emit light. Further, the control unit 48 controls the AF driver 84 to move the imaging lens 6 to a predetermined focus position. After this movement, the image pickup device driver 85 is controlled to capture the first to fifth chart images 56 to 60 imaged by the image pickup lens 6 by the image pickup device 12 (S3-2). The imaging signal output from the imaging element 12 is input to the focus coordinate value acquisition circuit 87 via the second probe unit 79.

The focus coordinate value acquisition circuit 87 extracts signals of pixels corresponding to the first to fifth imaging regions 89a to 89e from the input imaging signals, and calculates H-CTFs for the first to fifth imaging regions 89a to 89e from the pixel signals. Value and V-CTF value (S3-3). The H-CTF value and the V-CTF value are, for example, RAMs stored in the control unit 48.

Then, in order to measure the element unit 16 at the second measurement position set along the Z-axis direction, the control unit 48 executes the following steps S3-1 to S3-6 (S3-4 to S3-5). The measurement chart 52 is taken at the second measurement position, and the H-CTF value and the V-CTF value (S3-2 to S3-3) of the first to fifth imaging regions 89a to 89e are calculated. Hereinafter, the element unit 16 is moved to each measurement position in the same manner, and the H-CTF value and the V-CTF value (S3-2 to S3-5) are calculated.

The graphs of Figs. 13 and 14 show examples of H-CTF values of the first to fifth imaging regions 89a to 89e obtained at the respective measurement positions, that is, Ha1 to Ha5 and V-CTF values, i.e., Va1 to Va5. Further, the measurement position [0] indicates a position which becomes a design image plane with respect to the photographic lens 6. The focus coordinate value acquisition circuit 87 selects the maximum value from the calculated plurality of H-CTF values Ha1 to Ha5 and V-CTF values Va1 to Va5 for each imaging region of the first to fifth imaging regions 89a to 89e, and obtains The Z-axis coordinate at which the measurement position of the maximum value is obtained is used as the horizontal focus coordinate value and the vertical focus coordinate value of the first to fifth imaging regions 89a to 89e (S3-6).

In the example shown in Figs. 13 and 14, the H-CTF values ha1 to ha5 and the V-CTF values va1 to va5 are respectively the maximum values, and the measurement positions Z0 to Z5 and Z0 to Z4 corresponding to the CTF values are obtained. The Z-axis coordinate is used as the horizontal focus coordinate value and the vertical focus coordinate value.

The graphs shown in Figs. 15 and 16 show the state in which the ten evaluation points Hb1 to Hb5 and Vb1 to Vb5 are developed in the three-dimensional coordinate system of XYZ. The ten evaluation values Hb1 to Hb5 and Vb1 to Vb5 are obtained by XY coordinate axes of the respective imaging regions 89a to 89e when the imaging surface 12a corresponds to the XY coordinate plane, and Z obtained for each of the imaging regions 89a to 89e. A combination of the horizontal focus coordinate value and the vertical focus coordinate value on the axis. As can be seen from these curves, the actual image forming surface of the image pickup element 12 indicated by the horizontal evaluation points Hb1 to Hb5 and the vertical direction Vb1 to Vb5 is formed on the Z-axis due to manufacturing errors and assembly errors of the respective components. The imaging surface on the design on [0] is deviated.

The horizontal focus coordinate value and the vertical focus coordinate value acquired in the focus coordinate value acquisition circuit 87 are input to the interpolation circuit 92. The interpolation circuit 92 interpolates the in-focus evaluation value of each measurement coordinate value on the Z axis in each imaging region in a spline manner, and calculates the continuous focus evaluation value data (S5).

The continuous focus evaluation value data of each of the imaging regions 89a to 89e calculated by the interpolation circuit 92 is input to the specific imaging plane determination circuit 93, and the determination of the specific imaging plane is performed (S6). The determination of this particular imaging plane, as shown in Fig. 12, consists of sub-steps S6-1 to S6-8. The specific imaging plane determining circuit 93 obtains the Z-axis coordinate value (S6-1) of the peak value of the continuous focus evaluation data set in the first image region 89a at the center of the imaging surface 12a. Then, based on the respective in-focus evaluation data, an approximate plane approximate to the plane is calculated by the least squares method (S6-2).

The specific imaging plane determining circuit 93 arranges the calculated approximate plane on the assumed three-dimensional model, and makes the approximate plane toward the Z-axis coordinate value such that the intersection of the approximate plane and the Z-axis becomes the Z-axis coordinate value, that is, the peak value of the continuous focus evaluation data. Move (S6-3).

As shown in Fig. 17, the specific imaging plane determining circuit 93 constructs the calculated approximate plane 97 into a hypothetical three-dimensional space, and approximates the intersection of the plane 97 and the Z-axis as the Z-axis coordinate value, that is, the peak value of the continuous focus evaluation data. The approximate plane 97 is moved toward the Z-axis coordinate value. Then, centering on the position after the movement, each of the imaging planes is obtained from the intersection of the imaging regions of the plurality of imaging planes that can be moved around the X-axis and the Y-axis and the respective continuous focus evaluation data. The estimated resolution of the regions 89a to 89e (S6-5).

The specific imaging plane determining circuit 93v calculates the resolution change rate per unit length in the Z-axis direction for each of the continuous focus evaluation data (S6-5) simultaneously with the execution of the above-described processes (S6-1 to S6-4). . Then, the search range is set to each of the imaging areas of the respective imaging planes (S6-6). For example, as shown in Fig. 18, each search range determines a range P in which the resolution is less reduced by a predetermined threshold value with respect to the resolution change rate, and considers the predicted change amount of the imaging surface which is generated after adhesion. The distance allowance Q and the predetermined resolution allowable value R determine the search range M.

The specific imaging plane determining circuit 93 determines whether the estimated resolution of each of the imaging regions 89a to 89e in each imaging plane falls within each search range (S6-7), and if it falls completely within each search range, Determined to be a specific imaging plane (S6-8). When it is not in the range of the search, for example, it is determined in advance that the threshold value for reducing the range in which the resolution is reduced is small, or the parameter allowable value or the combined value of these combinations is loosened. Gradually expand each search range (S6-9) to determine whether each imaging plane falls within the search range.

The specific imaging plane determining circuit 93 determines, from each imaging plane, a specific imaging plane in which the balance evaluation value indicating the deviation of the estimated resolution of each of the imaging regions 89a to 89e is the smallest. The information of the specific imaging plane determined by the specific imaging plane determining circuit 93 is input to the adjustment value computing circuit 95. The adjustment value calculation circuit 95 calculates a Z-axis coordinate value which is an intersection of a specific imaging plane and the Z-axis, and an inclination around the X-axis and the Y-axis, that is, an XY-direction rotation angle with respect to a specific imaging plane of the XY coordinate plane, and is input and controlled. Part 48 (S7).

In the example shown in Fig. 19, for example, the distribution of the equilibrium evaluation values calculated by the equation (2) is constructed into a hypothetical three-dimensional space, and the optimum point Ha at which the balance evaluation value in each imaging plane becomes the smallest is calculated (specific The decision of the imaging plane). Find the angle θ around the X axis and the angle around the Y axis of the best point Ha Φ (refer to Figure 7).

The control unit 48 controls the two-axis rotating table 74 and the second sliding table 76 based on the Z-axis coordinate value and the XY-direction rotation angle, and causes the element unit 16 to face the Z-axis such that the center 12b of the imaging surface 12a coincides with the Z-axis coordinate value. mobile. Then, the angle of the θ direction and the Φ direction of the element unit 16 is adjusted such that the inclination of the imaging surface 12a coincides with the specific imaging plane (S8). After the position of the component unit 16 is adjusted, a step of confirming the in-focus position of the first to fifth imaging regions 89a to 89e is performed (S9). In this confirmation step, each step of the above S3 is performed again.

The graph shown in Fig. 20 shows an example of the result of the resolution of each measurement position of the first to fifth imaging regions 89a to 89e after the confirmation step is confirmed. From this curve, it is understood that after the position of the element unit 16 is adjusted, it has been confirmed in the prior art that the resolution of the substrate is reduced due to local deformation of the substrate. On the other hand, according to the adjustment method of the present invention, since the balance of the resolution is determined to be the smallest imaging plane with respect to the approximate plane, the resolution falls as a whole within a certain range. Therefore, if the degree distribution of the resolution of the resolution reduction portion shown in Fig. 21 is compared, the adjustment method of the present invention can improve the resolution of the falling portion. Further, when the comparison is made with the balance evaluation value of the entire imaging surface shown in Fig. 22, the adjustment method of the present invention can improve the balance of the resolution as a whole as compared with the conventional technique. Therefore, when the comparison is made with the degree distribution of the equilibrium evaluation value, as shown in Fig. 23, it is understood that the adjustment method of the present invention is concentrated in the vicinity of [0]. Thereby, as shown in Fig. 26B, the imaging plane 202 having the smallest deviation of the resolution of the entire imaging surface can be obtained as compared with the adjustment method (Fig. 26A) described in the prior art.

After the completion of the confirmation step (S9) (S4), the control unit 48 moves the element unit 16 in the Z-axis direction so that the center 12b of the imaging surface 12a coincides with the specific imaging plane plane coordinate value (S10). Moreover, the control unit 48 performs control to supply the ultraviolet curable adhesive (S11) from the adhesive supply unit 46 into the fitting portion 33, and illuminates the ultraviolet lamp 47 to cure the ultraviolet curable adhesive (S12). Then, the completed camera module 2 is taken out from the camera module manufacturing apparatus 40 by a robot (not shown) (S12).

In the confirmation step, the Product management value (PMV) is obtained from the estimated resolution and the measured resolution of the specific imaging plane. Here, as the resolution, a CTF value (contrast transfer function) is used. From the estimated CTF value and the measured CTF value, the PMV is obtained from the equation (3). This PMV is calculated for each H-CTF value and V-CTF value.

PMV = measured CTF value × estimated CTF value ... (3) It is preferable to set whether the obtained PMV is below a predetermined threshold value. When it is judged that it is less than a critical value, it is understood that the state of the device 40 is maintained, and if the critical value is exceeded, the state of the device 40 is not maintained. By providing such a judging means, it is possible to grasp the maintenance period of the device 40, and also to secure the resolution of each pixel region secured by the hypothesis space and the magnitude of the deviation of the overall resolution in the real space.

As is apparent from the above description, the element unit 16 performs position adjustment so that the deviation from the overall resolution of the imaging surface 12a is the smallest or the imaging plane that satisfies the specifications, so that the screen can be stabilized even in the case of mass production of the camera module. quality. In addition, considering the range in which the resolution is less reduced, the amount of deformation after adhesion, and the like, the search range is determined for each imaging region, and the specific imaging plane is determined so as to fall within each search range. Therefore, the resolution of the imaging surface 12a is comprehensive. More than a certain value. Further, since the position adjustment is performed in such a manner as to match the imaging plane having the smallest deviation or satisfying the specification, the quality of the camera module 2 can be improved.

In each of the above embodiments, the CTF value is used as the in-focus evaluation value. However, the present invention is not limited to the CTF value, and can be applied to various evaluation methods capable of evaluating the resolution, the MTF value, and the like, and the evaluation value can be used for focusing. Measurement of position.

Further, as the CTF value, the H-CTF value and the V-CTF value in the horizontal direction and the vertical direction are used. As shown in the measurement chart 130 of Fig. 24, the radial direction of the photographic lens can also be calculated by using the line 131a along the radial direction of the photographic lens and the chart image 131 along the line 131b perpendicular to the radial direction. S-CTF value and T-CFT value in the vertical direction. Further, all of the H-CTF value, the V-CTF value, the S-CTF value, and the T-CFT value may be calculated in each imaging region, and the CTF value calculated for each imaging region may be changed. Alternatively, the focus position can be measured by performing an operation using any one of H-CTF value, V-CTF value, S-CTF value, and T-CFT value or any combination thereof.

Further, as shown in the measurement chart 135 of Fig. 25, the surface of the figure may be divided with respect to the center position in the X-axis direction, the Y-axis direction, and the two diagonal directions, and the first to fourth quadrants may be respectively provided. In two areas of 136 to 139, a plurality of parallel lines perpendicular to each other are disposed. According to this measurement chart 135, the chart pattern along the diagonal line is the same regardless of the position, so that it can also serve as the position adjustment for the image pickup elements of different image angles. Moreover, the lines provided in the respective areas may be horizontal lines and vertical lines.

In each of the above embodiments, the position of the measurement chart 52 and the lens unit 15 is fixed, but at least one of them may be moved in the Z-axis direction in advance, and the distance between the measurement chart 52 and the lens barrel 20 by a laser displacement meter or the like is used. The measurement is performed, and the position adjustment is performed such that the distance falls within the predetermined value, and then the position adjustment of the element unit 16 is performed. Thereby, high-precision position adjustment can be performed.

Further, although the position adjustment of the element unit 16 is performed only once, it may be repeated a plurality of times. Further, the position adjustment of the component unit 16 of the camera module has been described as an example, but it is also possible to adjust the position of the imaging element of a general digital camera.

2. . . Camera module

5. . . Photography opening

6. . . Photographic lens

7~9. . . Positioning recess

7a, 9a. . . Positioning hole

11. . . Rectangular opening

12. . . Camera element

12a. . . Camera

13. . . contact

15. . . Lens unit

16. . . Component unit

19. . . Unit body

20. . . Lens barrel

twenty one. . . Front cover

twenty four. . . Reed

25. . . permanent magnet

26. . . Electromagnet

26a. . . contact

29. . . Component frame

32. . . Mating piece

33. . . Mating slot

36. . . gap

37. . . Concave

40. . . Camera module manufacturing device

41. . . Chart unit

41a. . . Chart box

42. . . Concentrating unit

42a. . . support

42b. . . Condenser lens

42c. . . Opening

43. . . Lens positioning plate

43a. . . Opening

44. . . Lens retention mechanism

45. . . Component moving mechanism

46. . . Adhesive feeder

47. . . ultra violet light

48. . . Control department

49. . . Workbench

52. . . Measurement chart

53. . . light source

52a. . . center

56~60. . . 1st to 5th chart images

56a～60a. . . Horizontal chart image

56b~60b. . . Vertical chart image

63~65. . . Abutment pin

63a, 65a. . . Insert pin

68. . . Holding plate

68b. . . Holding arm

69. . . 1st slide

68a. . . Horizontal base

69a. . . Taiwan Department

70a. . . Probe

70. . . First probe unit

72. . . Chuck hand

72a. . . Holding member

72b. . . Actuator

74. . . 2-axis rotary table

76. . . 2nd slide

81. . . Input device

82. . . Monitor

84. . . AF drive

87. . . Focus coordinate value acquisition circuit

89a～89e. . . First to fifth imaging areas

92. . . Interpolation circuit

93. . . Specific imaging plane decision circuit

95. . . Adjustment value operation circuit

Fig. 1 is a perspective view of the camera module of the present invention as seen from the front side.

Fig. 2 is a perspective view of the camera module as viewed from the back side.

Fig. 3 is an exploded perspective view of the lens unit and the element unit.

Figure 4 is a cross-sectional view of the camera module.

Fig. 5 is a schematic view showing the configuration of a camera module manufacturing apparatus.

Figure 6 is a top view of the measurement chart.

Fig. 7 is an explanatory view showing a state in which a lens unit and an element unit are held on a camera module manufacturing apparatus.

Fig. 8 is a block diagram showing the configuration of a camera module manufacturing apparatus.

Fig. 9 is an explanatory view showing each imaging area set on the imaging surface.

Figure 10 is a flow chart showing the manufacturing sequence of the camera module.

Figure 11 is a flow chart showing the steps of obtaining the focus coordinate value.

Figure 12 is a flow chart showing the steps of determining a particular imaging plane.

Fig. 13 is a graph showing the H-CTF value of each imaging region before the component unit adjustment.

Fig. 14 is a graph showing V-CTF values of respective imaging regions before adjustment of the element unit.

Fig. 15 is a three-dimensional graph showing evaluation points of respective imaging regions before adjustment of the element unit from the X-axis side.

Fig. 16 is a three-dimensional graph showing evaluation points of respective imaging regions before adjustment of the element unit from the Y-axis side.

Fig. 17 is an explanatory diagram showing an approximate plane arranged in a hypothetical three-dimensional space.

Fig. 18 is a graph showing a setting example of the search range in the continuous focus evaluation data.

Fig. 19 is a view for explaining the distribution of the balance evaluation values calculated for each imaging plane based on the estimated resolution of each imaging region in the assumed three-dimensional space.

Fig. 20 is a graph showing the resolution of the imaging region confirmed after the adjustment.

Figure 21 is a graph showing the degree distribution of the resolution measured by the adjusted camera modules.

Fig. 22 is a graph showing the balance evaluation values of the respective imaging planes confirmed after the adjustment.

Fig. 23 is a graph showing the degree distribution of the equilibrium evaluation value confirmed after the adjustment.

Fig. 24 is a plan view showing a measurement chart used when calculating the CTF value in the radial direction of the photographic lens and the direction perpendicular to the direction.

Fig. 25 is a plan view of a measurement chart for position adjustment of image pickup elements of different drawing angles.

Fig. 26A is an explanatory view showing a state in which an approximate imaging surface is calculated by a conventional technique in the case where the substrate is locally deformed, and Fig. 26B is an explanatory view showing a state in which an approximate imaging surface is calculated by the present invention.

Claims (6)

A position adjustment method for adjusting a position of an image pickup element with respect to a photographic lens, the position adjustment method comprising the steps of: sequentially aligning the photographic lens or the image pickup element with each other on a Z axis perpendicular to the measurement chart The measurement coordinate value is moved, and the measurement chart is captured by the imaging element on each measurement coordinate value; the central portion and the two or more peripheral portions set on the imaging surface of the imaging device are used as imaging regions, and are obtained from the regions. The image pickup signal acquires an individual focus evaluation value indicating the degree of focus in each imaging area for each of the measurement coordinate values; and interpolates the focus evaluation value of each measurement coordinate value on the Z axis in each of the imaging areas to calculate continuous Focus evaluation value data; obtaining a Z-axis coordinate value of the peak of the continuous focus evaluation value data set in the imaging area at the center of the imaging surface; and expanding at least three or more evaluation points on the combined XY coordinate plane and the Z-axis When the three-dimensional coordinate system is formed, the approximate position expressed as a plane in the three-dimensional coordinate system is calculated based on the relative positions of the evaluation points. And at least three or more evaluation points are represented by a combination of an XY coordinate axis of each imaging region when the imaging surface corresponds to the XY coordinate plane perpendicular to the Z axis, and a measurement coordinate value on the Z axis. Moving the approximate plane in such a manner that the intersection of the approximate plane and the Z-axis becomes the Z-axis coordinate value, and a plurality of imaging planes that are movable about the X-axis and the Y-axis perpendicular to the Z-axis centering on the position With each continuous focus Evaluating the intersection of the data, determining the estimated resolution of each of the imaging regions in each imaging plane; determining a specific imaging plane based on the balance evaluation value indicating the deviation of the estimated resolution; and calculating as the Z-axis and the specific imaging plane The image plane coordinate value of the intersection point, and the rotation angle of the specific imaging plane relative to the X-axis and the Y-axis of the XY coordinate plane, so that the imaging plane coincides with the specific imaging plane. The position adjustment method of claim 1, wherein the specific imaging surface determining step includes: calculating, for each of the continuous focus evaluation data, a resolution change rate per unit length of the Z-axis direction; and changing the resolution The range of low rate is defined as the search range, and the specific imaging plane is determined within this search range. A method of manufacturing a camera module having a lens unit for holding a photographic lens and an element unit for holding an imaging element, the method of manufacturing the camera module having the following steps: on a Z-axis perpendicular to the measurement chart One of the lens unit or the element unit is sequentially moved toward the measurement coordinate value, and the measurement chart is captured by the imaging element on each measurement coordinate value; the central portion and the two or more portions set on the imaging surface of the imaging element are The peripheral portion is used as an imaging region, and based on the imaging signals obtained from the regions, each measurement coordinate value on the Z-axis is obtained and displayed in each imaging An individual focus evaluation value of the focus degree of the region; an in-focus evaluation value of each measurement coordinate value on the Z axis in each of the imaging regions is interpolated, and a continuous focus evaluation value data is calculated; and an image set in the center of the imaging surface is obtained The Z-axis coordinate value of the peak of the continuous focus evaluation value data in the region; when the three or more evaluation points are developed on the three-dimensional coordinate system in which the XY coordinate plane and the Z-axis are combined, the relative position of the evaluation points is determined based on Calculating an approximate plane represented as a plane in the three-dimensional coordinate system, and the at least three or more evaluation points are XY coordinate axes of the respective imaging regions when the imaging surface corresponds to the XY coordinate plane perpendicular to the Z axis And a combination of measured coordinate values on the Z-axis; the approximate plane is moved in such a manner that the intersection of the approximate plane and the Z-axis becomes the Z-axis coordinate value, and is perpendicular to the center according to the position An intersection of a plurality of imaging planes of the X-axis and the Y-axis of the Z-axis and the continuous focus evaluation data, and an estimated resolution of each imaging region in each imaging plane is obtained; The balance evaluation value of the deviation determines a specific imaging plane; and calculates an imaging surface coordinate value as an intersection of the Z axis and the specific imaging plane, and the X-axis and the Y-axis of the specific imaging plane relative to the XY coordinate plane Rotating the angle so that the imaging surface coincides with the specific imaging plane; and the position of the imaging element has been adjusted relative to the photographic lens In the state, the lens unit is fixed to the element unit. The method of manufacturing a camera module according to claim 3, wherein the fixing step adheres the lens unit to the component unit with an ultraviolet curing adhesive. A camera module manufacturing apparatus comprising: a measurement chart provided with a chart graphic; and a lens unit holding unit that holds and sets a lens unit on which a photographic lens is mounted on a Z axis perpendicular to the measurement chart; And maintaining and setting the component unit on which the imaging element is mounted on the Z-axis, and changing the position on the Z-axis of the component unit and the inclination of the X-axis and the Y-axis perpendicular to the Z-axis; The position moving unit moves the lens unit holding unit or the element unit holding unit so that the imaging lens or the imaging element sequentially moves a plurality of measurement coordinate values previously dispersed on the Z axis. The imaging element control unit causes the imaging element to capture a measurement chart for each value of the measurement coordinate value on the Z axis; the focus coordinate value acquisition unit sets a central portion of the imaging surface of the imaging element and Two or more peripheral portions are used as imaging regions, and based on the imaging signals obtained from the regions, the degree of focusing in each imaging region is calculated for each measurement coordinate value on the Z-axis. The individual focus evaluation value; the interpolation unit interpolates the focus evaluation value of each measurement coordinate value on the Z axis in each of the imaging regions, and calculates the continuous focus evaluation value data; The Z-axis coordinate value acquisition unit obtains a Z-axis coordinate value which is a peak value of the continuous focus evaluation value data set in the imaging region at the center of the imaging surface, and the approximate plane calculation unit is configured to have at least three evaluation points. When expanding into a three-dimensional coordinate system in which an XY coordinate plane and a Z-axis are combined, an approximate plane represented as a plane in the three-dimensional coordinate system is calculated based on the relative positions of the evaluation points, wherein the at least three The evaluation point is expressed by a combination of the XY coordinate axis of each imaging region when the imaging surface corresponds to the XY coordinate plane perpendicular to the Z axis, and the measurement coordinate value on the Z axis; the estimated resolution acquisition unit, The approximate plane is moved in such a manner that the intersection of the approximate plane and the Z-axis becomes the Z-axis coordinate value, and a plurality of imaging planes that are movable around the X-axis and the Y-axis based on the position and the continuous The intersection of the focus evaluation data is obtained, and the estimated resolution of each imaging region in each imaging plane is obtained; the specific imaging plane determining unit determines the specificity based on the balance evaluation value indicating the deviation of the estimated resolution. An image plane; an adjustment unit calculates an image plane coordinate value as an intersection of the Z axis and the specific imaging plane, and a rotation angle of the specific imaging plane relative to the XY coordinate plane about the X axis and the Y axis, such that The imaging surface is aligned with the specific imaging plane; and the fixing portion fixes the lens unit and the component unit in a state where the position of the imaging element is adjusted with respect to the photographic lens. The camera module manufacturing apparatus according to claim 5, wherein the specific imaging surface determining unit calculates a resolution change rate per unit length in the Z-axis direction of each of the continuous focus evaluation data, and the resolution is obtained. The range in which the rate of change is small is defined as the search range within which the specific imaging plane is determined.