JP2014179764A - Position adjustment device for image pickup element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position adjustment device for an image pickup element that is inexpensive, achieves space saving, and can secure a sufficient margin of tilt adjustment of the image pickup element through simple constitution in which the interval between a photographic lens and the image pickup element is widened.SOLUTION: A position adjustment device for an image pickup element includes a tilt adjustment part 20 which adjusts a tilt of the image pickup element on a Z axis and tilts on an X axis and a Y axis crossing the Z axis based upon a chart image of a measurement chart 1 imaged by the imaging element while one of a lens unit holding part 11 and an image pickup unit holding part is moved by a moving mechanism 20 along the Z axis. Here, the distance L between the measurement chart 1 and a photographic lens 72 satisfies a condition of 200 mm≤L≤2,000 mm.

Description

  The present invention relates to an image sensor position adjusting device, and more particularly to an image sensor position adjusting device that adjusts the tilt of the image sensor relative to a photographic lens.

  As a conventional first image sensor position adjustment device, the lens holding mechanism holds the lens unit, the element moving mechanism holds the image pickup unit in which the image pickup element is incorporated, and the slide unit moves the image pickup unit in the Z-axis direction. The chart image formed by the photographing lens is picked up by the image pickup element while being moved to the position, and in-focus coordinate values of at least five image pickup positions set on the image pickup surface are acquired (for example, Japanese Patent Application Laid-Open No. 2010-2010). 21985 publication (patent document 1)). This conventional first image sensor position adjustment device calculates an approximate imaging plane from the relative positions of a plurality of evaluation points obtained by developing in-focus coordinate values obtained for each imaging position in a three-dimensional coordinate system. The position and inclination of the image pickup unit are adjusted by the second slide stage and the biaxial rotation stage so that the image pickup surface coincides with the approximate imaging plane.

  Further, as a conventional second image sensor position adjustment device, there is an apparatus that adjusts the position and angle of an image sensor using two test charts (for example, Japanese Patent Application Laid-Open No. 2006-30256 (Patent Document). 2)). In this conventional second image sensor position adjustment device, first, focus evaluation is performed using the first test chart provided with a black and white pattern (focus), and the peripheral light amount ratio is determined using the second test chart which is a white chart. Measurement is performed to obtain an adjustment angle (sensor tilt amount) of the image sensor. In the conventional second image sensor position adjusting device, the peripheral light amount ratio cannot be said to have a correlation of 100% with the resolution, and the peripheral light amount ratio is a characteristic of the light source (for subject illumination) and the lens. Therefore, the influence of the illuminance distribution can be reduced by using a uniform light source having no variation in the illuminance distribution, but the cost increases. In addition, in the above-described image sensor position adjustment apparatus, if a non-uniform light source having a variation in illuminance distribution is used, the cost can be reduced, but the calculation result of the tilt of the image sensor varies.

JP 2010-21985 JP 2010-21985

  However, in the above-described conventional first and second image sensor position adjustment devices, particularly when the adjustment angle of the image sensor is large in a camera module in which the gap between the imaging lens of the lens unit and the image sensor of the image unit is narrow. However, there is a problem that a sufficient margin for tilt adjustment cannot be secured.

  Accordingly, an object of the present invention is to provide a low-cost and space-saving position adjustment device for an image sensor that can sufficiently secure a margin for adjusting the tilt of the image sensor with a simple configuration that increases the distance between the photographing lens and the image sensor. Is to provide.

In order to solve the above-described problems, an image sensor position adjusting device according to the present invention includes:
A measurement chart in which a plurality of chart patterns are formed;
A lens unit holding unit for holding a lens unit in which a photographing lens arranged on the Z axis orthogonal to the measurement chart is incorporated;
An imaging unit holding unit for holding an imaging unit in which an imaging element arranged on the Z-axis is incorporated so as to capture a chart image of the measurement chart formed by the imaging lens;
A moving mechanism for moving either the lens unit holding unit or the imaging unit holding unit along the Z-axis direction;
Based on the chart image of the measurement chart imaged by the imaging device while moving either the lens unit holding unit or the imaging unit holding unit along the Z-axis direction by the moving mechanism, the imaging device An inclination adjustment unit that adjusts the inclination about the Z axis and the inclination about the X axis and the Y axis perpendicular to the Z axis,
The distance L between the measurement chart and the photographic lens is
200mm ≤ L ≤ 2000mm
It satisfies the following conditions.
The image sensor position adjusting device of the present invention does not include a lens unit and a photographing unit.

In the image sensor position adjustment device of one embodiment,
The distance L between the measurement chart and the photographic lens is
400mm ≤ L ≤ 1000mm
Satisfy the condition of

In the image sensor position adjustment device of one embodiment,
A filling portion for filling an adhesive into at least a part of the gap between the lens unit and the photographing unit is provided.

In the image sensor position adjustment device of one embodiment,
The filling unit is configured to attach an ultraviolet curable adhesive or a thermosetting adhesive to at least a part of the gap before adjusting the angles around the X axis, the Y axis, and the Z axis of the imaging element by the inclination adjusting unit. At least one of the agents is filled.

  According to the above embodiment, before the adjustment by the tilt adjustment unit, at least one of the ultraviolet curable adhesive or the thermosetting adhesive is filled into the gap between the lens unit and the photographing unit by the filling unit. This makes it possible to easily fill the gap between the lens unit and the photographing unit before adjusting the inclination of the image sensor, and to reduce the gap between the lens unit and the photographing unit after adjusting the inclination. Even in such a case, the lens unit and the photographing unit can be reliably and easily adhered by irradiating the heated adhesive or heating the adhesive.

In the image sensor position adjustment device of one embodiment,
Based on the chart image picked up by the image pickup device, the X axis of the image pickup surface of the image pickup device with respect to the image formation surface of the chart image formed by the photographing lens using SFR (spatial frequency response), Y An inclination calculation unit for calculating the inclination about the axis and the Z axis;
The tilt adjustment unit is configured to rotate around the X axis, Y axis, and Z axis of the image sensor based on the tilt around the X axis, Y axis, and Z axis of the imaging surface of the image sensor calculated by the tilt calculation unit. Adjust the tilt.

  According to the embodiment, based on the chart image captured by the image sensor, the X axis of the imaging surface of the image sensor with respect to the imaging surface of the chart image formed by the photographing lens using SFR (spatial frequency response) , Y axis and Z axis inclination is calculated by the inclination calculation unit, so that focusing evaluation can be performed accurately even from a blurred image by SFR (spatial frequency response), and the chart image formed by the photographing lens can be formed. The inclination of the imaging surface of the imaging device with respect to the surface about the X axis, Y axis, and Z axis can be accurately calculated.

  As is clear from the above, according to the present invention, the gap between the photographic lens and the image sensor is widened, so that the margin for adjusting the tilt of the image sensor is sufficiently large with a simple configuration that widens the distance between the photographic lens and the image sensor. Thus, it is possible to realize a low-cost and space-saving position adjustment device for an image sensor.

  Further, by arranging the measurement chart at a short distance with respect to the photographing lens, the apparatus main body can be downsized not only in the optical axis direction but also in the width direction and the depth direction.

  In addition, the position of the image sensor can be adjusted with a measurement chart smaller than the measurement chart arranged near the telephoto end, and manufacturing costs such as material costs and processing costs can be reduced.

  In addition, by securing the distance between the imaging lens and the imaging element when adjusting the position of the imaging element, the imaging lens is less likely to interfere with the imaging lens even when the adjustment angle is large, and can be adjusted in the mass production process. The absolute number of camera modules can be increased.

  In this way, an increase in the number of adjustable camera modules reduces the number of defective products and improves the yield, so that the manufacturing cost can be reduced.

FIG. 1 is a perspective view showing a schematic configuration of an image sensor position adjusting apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the configuration of the lens unit and the imaging unit of the image sensor position adjusting device. FIG. 3 is a plan view of a measurement chart of the position adjusting device for the image sensor. FIG. 4 is a diagram showing the relationship between the subject distance and the focal position movement amount. FIG. 5 is a diagram illustrating the relationship between the gap between the photographic lens and the image sensor and the allowable rotation angle of the image sensor. FIG. 6 is a diagram for explaining the relationship of the focal position with respect to the subject distance of the lens unit and the imaging unit. FIG. 7 is a diagram for explaining the tilt adjustment of the imaging unit. FIG. 8 is a diagram showing the correlation between the subject distance and the SFR value at an image height of 0% of the image sensor position adjusting apparatus according to the second embodiment of the present invention. FIG. 9 is a diagram showing the correlation between the subject distance and the SFR value at an image height of 60% of the image sensor position adjusting device. FIG. 10 is an enlarged view of the main part of FIG. FIG. 11 is an enlarged view of a main part of FIG. FIG. 12 is a diagram showing the correlation between the subject distance and the SFR value at an image height of 90%. FIG. 13 is a diagram for explaining variations in peak coordinates based on the SFR value of the peripheral image height with respect to the image center. FIG. 14 is a block diagram of a control device for an image sensor position adjusting device according to a third embodiment of the present invention.

  Hereinafter, an image sensor position adjusting device according to the present invention will be described in detail with reference to embodiments shown in the drawings.

[First Embodiment]
FIG. 1 is a perspective view showing a schematic configuration of an image sensor position adjusting apparatus according to a first embodiment of the present invention. In the first embodiment, the position of the image sensor of a camera module used for a smart phone or a digital camera is adjusted.

  As shown in FIG. 1, the position adjustment device for the image sensor according to the first embodiment includes a measurement chart 1 and a lens positioning jig having a lens holding mechanism 11 as an example of a lens unit holding unit that holds the lens unit 2. 10 and an inclination adjustment unit 20b for adjusting the inclination of the imaging unit around the Z axis and the inclinations around the X axis and the Y axis perpendicular to the Z axis based on the chart image captured by the imaging unit 3 and the imaging unit holding The moving mechanism 20 including the part 20a is provided.

  The lens unit 2 is disposed on the Z axis orthogonal to the measurement chart 1. The image pickup unit 3 (sensor substrate) is mounted with an image pickup element 82 (shown in FIG. 2) arranged on the Z axis so as to pick up a chart image formed by the lens unit 2.

  As shown in FIG. 2, the lens unit 2 includes a unit main body 71, a photographing lens 72 incorporated in the unit main body, and a VCM (Voice Coil Moto: voice) that moves the photographing lens 72 along the optical axis direction. -Coil motor) 73. The photographing lens 72 is mainly composed of, for example, 3 to 5 plastic lenses or glass lenses (in the first embodiment, it is composed of 3 lenses).

  Further, as shown in FIG. 2, the imaging unit 3 includes a substrate 81 and an imaging element 82 mounted on the substrate 81.

  In addition, the moving mechanism 20 shown in FIG. 1 moves in the Z-axis direction, moves in the X-axis direction perpendicular to the Z-axis, moves in the Y-axis direction perpendicular to the Z-axis and the X-axis, and rotates around the Z-axis. And a 6-axis stage having a function of rotating around the X axis and rotating around the Y axis.

  In addition, the image sensor position adjusting device applies a VCM 73 (shown in FIG. 2) of the lens unit 2 and a control device 30 that controls the moving mechanism 20 and an adhesive for fixing the imaging unit 3 to the lens unit 2. An adhesive application device 40 as an example of a filling unit that performs this process and a UV irradiator 50 that irradiates ultraviolet rays to harden the adhesive are provided.

  Based on the chart image picked up by the image pickup device 82, the control device 30 uses the SFR (spatial frequency response) to image the image pickup surface of the image pickup device 82 with respect to the image formation surface of the chart image formed by the photographing lens 72. An inclination calculating unit 30a that calculates inclinations around the X, Y, and Z axes is provided. The control device 30 may be a personal computer or may be composed of a microcomputer and an input / output circuit.

  The image sensor position adjustment apparatus having the above-described configuration is disposed on, for example, a vibration isolation table.

In addition, the specification of the imaging unit of the camera module that is adjusted using the image sensor position adjusting device of this embodiment is as follows.
Number of pixels: 8 million pixels Image sensor: CMOS sensor Focal length: 4.2 mm

  Further, the measurement chart 1 has a light source (reflection type or transmission type) for chart illumination.

  In addition, the moving mechanism 20 (shown in FIG. 1) is disposed at the lower part of the suction unit holding portion 20a including a suction pad (not shown) that sucks the imaging unit 3 (sensor substrate), and is provided on the control device. And a six-axis stage (not shown) including an inclination adjusting unit 20b controlled by 30 (shown in FIG. 1).

  In FIG. 1, the upper surface of a suction pad (not shown) that sucks the lens unit 2 is used as a reference surface, and the distance L from the reference surface to the measurement chart 1 is 600 mm.

  An air pump (not shown) is connected to the suction pad (not shown) of the lens holding mechanism 11 and the suction pad (not shown) of the moving mechanism 20. The suction force of the air pump attracts and positions the lens unit 2 on the suction pad of the lens holding mechanism 11 and positions the imaging unit 3 on the suction pad of the moving mechanism 20.

  FIG. 3 is a plan view of the measurement chart 1 of the position adjusting device for the image sensor. As shown in FIG. 3, the measurement chart 1 is divided into four quadrants by a perpendicular line and a horizontal line passing through the center of the rectangular chart surface. Black square chart patterns 61 and 61 are printed on the first and second quadrants of the chart surface of the measurement chart 1. In addition, black square chart patterns 62 and 62 are printed on the third and fourth quadrants of the chart surface of the measurement chart 1, and a chart pattern 63 is printed at the center of the chart surface.

  FIG. 4 shows the relationship between the subject distance L and the amount of movement of the focal position movement amount D (the amount of deviation between the imaging surface and the imaging surface of the image sensor 82) in the camera module composed of the lens unit 2 and the imaging unit 3. Yes. In the camera module set so that an image of an object at infinity is focused on the imaging surface of the imaging unit 3 by the lens unit 2, for the measurement chart 1 arranged at a position of 600 mm, By extending the photographic lens 72 to the subject side by 0.029 mm, the chart image of the measurement chart 1 is focused on the imaging surface of the imaging device 82 (the focusing surface is shifted).

  Therefore, by lifting the lens unit 2 in the direction of the measurement chart 1 or lowering the imaging unit 3 (sensor substrate) in the direction opposite to the measurement chart 1 (on the imaging element 82 side) as shown in FIG. Since the gap between the photographic lens 72 and the image sensor 82 can be increased by 0.029 mm as compared with the conventional process (the lens unit and the image sensor unit are brought into mechanical contact with each other), the inclination of the image sensor 82 is increased. The space that can be used for adjustment is expanded.

  For this reason, the margin for adjusting the inclination of the imaging unit 3 is widened with respect to the rotation angle of the imaging unit 3 (sensor substrate) obtained by the focus evaluation value analysis. Then, as shown in FIG. 7, after adjusting the tilt of the imaging unit 3, the lens unit 2 is lowered by 0.029 mm with respect to the Z-axis direction (an infinity lens design position), and the lens unit 2 and the imaging unit 3 are moved. Adhere with an adhesive.

  For example, in the analysis of the focus evaluation value in the measurement chart 1 with a distance of 600 mm from the photographing lens 72, ± 30 ′ (= ± 0) is obtained by securing a stroke of 60 μm to 100 μm in the Z-axis direction of the imaging unit 3. Sensor adjustment (θx, θy) of .5 ° × 60) is possible.

  In the analysis of the focus evaluation value, the chart image formed by the photographing lens 72 of the lens unit 2 is picked up by the image pickup element 82 of the image pickup unit 3 while moving the image pickup unit 3 in the Z-axis direction, The focus evaluation value of each chart pattern of the chart image is acquired using the set evaluation area. An approximate imaging plane is calculated by developing the focusing evaluation value of each chart pattern obtained for each evaluation area in a three-dimensional coordinate system, and imaging is performed so that the imaging plane matches the approximate imaging plane. Adjust the tilt of unit 3.

  Before adjusting the tilt of the image pickup unit 3, UV + heat combination adhesive is applied to a predetermined area on the substrate 81 on which the image pickup element 82 of the image pickup unit 3 is mounted, thereby adjusting the tilt of the image pickup unit 3. After that, ultraviolet rays are irradiated from the UV irradiator 50 through the optical fiber 51. Thus, the adhesive is temporarily cured so that the relative positional relationship between the lens unit 2 and the imaging unit 3 can be maintained, and then the adhesive is fully cured in a high temperature furnace. In this embodiment, the UV + heat combination type adhesive is used. However, the present invention is not limited to this, and an instantaneous adhesive, a thermosetting adhesive, a natural curing adhesive, or the like may be used.

  In this embodiment, after adjusting the angle of the image pickup unit 3, the gap between the lens unit 2 and the image pickup unit 3 is not filled with an adhesive, but is applied in advance before adjusting the angle of the image pickup unit 3.

  When the subject distance (the distance between the measurement chart 1 and the imaging unit 3) is increased, not only the position adjustment apparatus increases in the height direction but also increases in the width direction and the depth direction. Further, regarding the production cost of the measurement chart, it is difficult to print on one large sheet at a time, and one large plate material that does not bend is required, so that the cost is greatly increased.

The rotation system around the X axis and the Y axis of the image pickup unit 3 is an automatic biaxial goniometer stage, and the rotation of the two motors makes the image pickup unit 3 around the X axis around the center of the image pickup surface. The imaging unit 3 is tilted in the θ _X direction and the θ _Y direction around the Y axis orthogonal to the Z axis and the X axis. Thereby, when the imaging unit 3 is tilted in each direction, the positional relationship between the center of the imaging surface and the Z axis is prevented from being shifted.

  In the embodiment described above, the focus evaluation value analysis is performed using a spatial frequency response. In the focus evaluation value analysis, other evaluation values such as an MTF (Modulation Transfer Function) value may be used. For example, since the same items are inspected in the imaging test of the completed camera module composed of the lens unit 2 and the imaging unit 3, the contrast ratio of the chart pattern is calculated and the focus evaluation is performed. Also good.

  Regarding the adjustment angle of the imaging unit 3 when the gap between the photographic lens 72 and the imaging element 82 is widened by 0.029 mm from the design value (back focus), for example, the outer shape of the lens unit 2 and the imaging element 82 of the imaging unit 3. When the outer shape of the board on which is mounted is □ 8.3 mm, there is a margin of ± 24 ′ (= ± 0.4 ° × 60). In this embodiment, the maximum rotation angle of the image pickup unit 3 is assumed to be ± 20 ′ (≈ ± 0.33 ° × 60), and the (design value + 0.029 mm) between the photographing lens 72 and the image pickup device 82 is assumed. ) Is provided with a sufficient gap for adjusting the inclination of the imaging unit 3.

  When the outer shape of the imaging unit 3 is □ 8.3 mm, the relationship between the gap between the photographing lens 72 and the imaging element 82 and the allowable rotation angle of the imaging element 82 is as shown in FIG.

  According to the image sensor position adjusting apparatus of the first embodiment, by arranging the measurement chart 1 at a short distance (600 mm) with respect to the photographing lens 72, not only in the optical axis direction but also in the width direction and the depth direction. In contrast, the position adjusting device main body can be reduced in size, and the manufacturing cost of the measurement chart 1 can be reduced.

  In addition, by securing a sufficient gap between the imaging lens 72 and the imaging element 82 in the tilt adjustment of the imaging element 82, the imaging lens 72 is also connected to the imaging lens 72 with respect to the imaging lens 72 having a large adjustment angle of the imaging unit 3. 82 becomes difficult to interfere, the absolute number of camera modules that can be adjusted in the mass production process can be increased, the number of defective products is reduced, and the yield is improved, so that the manufacturing cost can be reduced.

  Further, the photographic lens 72 is moved to the subject side with respect to the position of the photographic lens 72 that forms an image of the subject at a position corresponding to infinity on the imaging surface of the imaging element 82, so that the photographic lens 72 and the imaging element 82 are moved. The inclination of the image sensor 82 can be adjusted by widening the distance between the image sensor 82 and the margin for adjusting the tilt can be sufficiently secured even if the adjustment angle of the image sensor 82 and the photographing lens 72 by the active alignment is large. Instead of moving the photographic lens 72 to the subject side, the image sensor 82 may be moved to the side opposite to the subject.

  In addition, the imaging unit 3 in which the gap between the lens unit 2 and the lens unit 2 varies after the inclination is adjusted by filling an adhesive into the gap between the lens unit 2 and the imaging unit 3 by the adhesive application device 40 (filling unit). Can be easily fixed to the lens unit 2.

  In addition, before adjustment by the inclination adjusting unit 20b of the moving mechanism 20, at least one of an ultraviolet curable adhesive or a thermosetting adhesive is bonded to at least a part of the gap between the lens unit 2 and the imaging unit 3. By filling with the agent coating device 40, the adhesive between the lens unit 2 and the image pickup unit 3 can be easily filled in the state before adjusting the inclination of the image pickup element 82, and the lens unit 2 and the image pickup after the inclination adjustment. Even if there is a portion where the distance from the unit 3 is narrow, the lens unit 2 and the imaging unit 3 can be securely and easily bonded by irradiating the heated adhesive with ultraviolet rays or heating the adhesive.

  Further, based on the chart image picked up by the image pickup device 82, the X axis of the image pickup surface of the image pickup device 82 with respect to the image formation surface of the chart image formed by the photographing lens 72 using SFR (spatial frequency response), Since the inclination calculation unit 30a calculates the inclination about the Y-axis and the Z-axis, the focus evaluation can be performed with high accuracy even from a blurred image by SFR (spatial frequency response), and the result of the chart image formed by the photographing lens 72 can be obtained. The inclination about the X axis, Y axis, and Z axis of the image pickup surface of the image pickup element 82 with respect to the image plane can be accurately calculated.

[Second Embodiment]
Next, an image sensor position adjusting apparatus according to a second embodiment of the present invention will be described. The image sensor position adjusting apparatus of the second embodiment has the same configuration as the image sensor position adjusting apparatus of the first embodiment except for the subject distance.

  FIG. 8 shows the correlation between the subject distance and the SFR value at an image height of 0% of the image sensor position adjustment device of the second embodiment of the present invention, and FIG. 9 shows the subject at an image height of 60% of the image sensor position adjustment device. It is a figure which shows the correlation of distance and a SFR value.

  As shown in FIGS. 8 and 9, the SFR value representing the resolution is higher as the distance of the subject (measurement chart 1) is longer, and the peripheral image height near the center of the image is SFR relative to the distance of the subject (measurement chart 1). The value becomes higher.

  10 shows an enlarged view of the main part of FIG. 8, and FIG. 11 shows an enlarged view of the main part of FIG. As shown in FIGS. 10 and 11, when the numerical deterioration is 3% with respect to the SFR value of the object at infinity, the equivalent performance is exhibited at the object distance of 100 mm or more at the image height of 0%, and the image height of 0%. With a subject distance of 200 mm or more, the same performance is exhibited.

  Further, in FIG. 12 showing the correlation between the subject distance and the SFR value at 90% of the image height, the same performance is exhibited at the subject distance of 200 mm or more at the image height of 90%.

  Table 1 shows the numerical data of FIG. 10, Table 2 shows the numerical data of FIG. 11, and Table 3 shows the numerical data of FIG. 12 (in Tables 1 to 3, “Inf” represents infinity). .

  FIG. 13 is a diagram for explaining the variation in peak coordinates based on the SFR value of the peripheral image height with respect to the image center. In FIG. 13, the horizontal axis represents the Z-axis coordinate [mm], and the vertical axis represents the SFR value. In FIG. 13, the black diamond (♦) indicates the SFR value of 0% image height (“IH0.0”), and the black square (■) indicates the first image height 60% (“IH0.6− The SFR value of 1 ”) and the black triangle (() are the SFR value of the second image height of 60% (“ IH0.0-2 ”).

  As shown in FIG. 13, in the process of obtaining the adjustment angle of the image sensor 82 from the peak coordinate variation based on the SFR value of the peripheral image height with respect to the image center, if the SFR value is small, the influence of noise is large, and the reproducibility of the peak position is large. (Variation) and an analysis error are caused, and the reliability of the calculation result of the adjustment angle of the image sensor 82 is lowered. Therefore, the SFR value at each image height is preferably equivalent to the SFR value of the object at infinity, and the SFR value deterioration is 3% or less with respect to the SFR value of the object at infinity as a numerical range that does not have a large difference. Up to the characteristic guarantee area.

  By performing tilt adjustment in a region where an SFR value equivalent to the SFR value of an infinite subject can be obtained, the position adjustment device for the image sensor can be reduced in size and cost, and the adjustment accuracy can be improved.

  As shown in FIGS. 8 to 12, the resolution of the same image height decreases as the subject distance decreases. As shown in Tables 1 to 3, assuming that the subject resolution of an infinite subject is 1, the subject distance at which the resolution is degraded by 3% is 100 mm at an image height of 0%, 200 mm at an image height of 60%, and the image height. 90% is 200 mm. When the image height of 3% Less is allowed, the subject distance of the closest image is 200 mm.

  Further, in the region where resolution degradation is almost zero, the subject distance of the closest image is 600 mm.

  The arrangement of the measurement chart at infinity is difficult in practice, and the measurement chart 1 is arranged in an area (ideally 600 mm, 200 mm or more from the simulation result) where an SFR value equivalent to infinity is obtained. By performing the focus evaluation value analysis, it is possible to achieve both downsizing and cost reduction of the apparatus and adjustment accuracy.

  However, setting the lower limit of the subject distance to 200 mm assumes that a resolution degradation of 3% is allowed with respect to the resolution characteristics at infinity. The same resolution characteristics are required. Accordingly, from FIGS. 8 to 11, it is desirable that the subject distance is 400 mm or more.

  In addition, since there is a relationship between the subject distance and the focal position movement amount (the amount of extension of the photographing lens 72) shown in FIG. 4, the closer the subject distance is, the larger the gap between the photographing lens 72 and the image sensor 82 becomes. As for the position of, the one closer to the photographing lens 72 is fed forward than the measurement chart is arranged at infinity.

  As shown in FIG. 4, there is almost no change in the focal position movement amount (the amount by which the photographing lens 72 is extended), and the value is large with an inflection point of 2000 mm up to a subject distance of about 5000 mm. If a gap of at least 10 μm is not obtained with respect to the position of the infinitely far photographing lens 72, the gap is not secured with respect to the position of the infinitely far photographing lens 72. It is necessary to arrange within 2000 mm. From this point, the arrangement of the measurement chart 1 is set within 2000 mm from the photographing lens 72.

  Furthermore, it is more preferable to install the measurement chart 1 at a subject distance of 1000 mm that can effectively widen the gap between the imaging lens 72 and the imaging element 82. This not only reduces the size of the measurement chart and reduces the size of the device, but also contributes to cost reduction of the device.

  Further, when the apparatus is actually introduced, it is desirable that the height of the apparatus is within a maximum of 2 m to 3 m.

  From the above, the upper limit of the subject distance is set to 2000 mm, but is preferably set to 1000 mm or less.

  According to the image sensor position adjusting apparatus of the second embodiment, by setting the subject distance to 200 mm or more, the apparatus body can be downsized with the adjustment angle of the photographing lens 72 within an allowable error, and the measurement system (measurement housing) Body and measurement chart) and the adjustment accuracy can be improved.

In the image sensor position adjusting device of the second embodiment, the distance L between the measurement chart 1 and the photographic lens 72 is set as follows.
200mm ≤ L ≤ 2000mm
further,
400mm ≤ L ≤ 1000mm
More preferably.
By setting it within the range of this condition, it is possible to easily secure the distance between the imaging lens 72 and the imaging element 82 when the position of the imaging element 82 is adjusted while reducing the size of the apparatus main body.

[Third Embodiment]
FIG. 14 is a block diagram of the control device 130 of the image sensor position adjusting device according to the third embodiment of the present invention. The image sensor position adjusting device of the third embodiment has the same configuration as the image sensor position adjusting device of the first embodiment except for the control device, and FIGS.

  As shown in FIG. 14, the control device 130 is based on the chart image picked up by the image pickup device 82 and uses the SFR (spatial frequency response) to image the chart image formed by the photographing lens 72. An inclination calculation unit 130a that calculates inclinations around the X axis, Y axis, and Z axis of the imaging surface of the image sensor 82, and a chart pattern that includes at least a part of an imaging position set in advance on the imaging surface of the image sensor 82 A pattern evaluation unit 130b for recognizing an image and a focus evaluation value calculated using an evaluation region for each chart pattern of a chart image determined with reference to the position of the chart pattern recognized by the chart pattern recognition unit 130b. A focus evaluation value calculation unit 130c.

  When the photographic lens 72 or the image sensor 82 is moved in the Z-axis direction, the relationship between the imaging surface of the image sensor 82 of the imaging unit 3 and the image plane of the chart pattern changes due to the change in magnification. Generally, the closer the distance between the measurement chart 1 and the photographing lens 72 of the lens unit 2 is, the larger the change in magnification due to the movement of the photographing lens 72 is.

  In the method of the third embodiment, for example, the edge of the left side of the rectangular chart pattern is detected by image processing (pattern matching), and processing for analyzing a predetermined area from that point according to each image height is performed. ing.

  According to the image sensor position adjustment apparatus of the third embodiment, stable operation of the apparatus can be realized, and adjustment accuracy can be improved.

  Further, even if the image magnification is changed by moving the lens unit 2 or the imaging unit 3 in the Z-axis direction and the relationship between the imaging surface of the imaging element 82 and the imaging surface of the chart image is changed, a specific imaging region Since the chart pattern is recognized and the evaluation area of each chart pattern is determined based on the position of the chart pattern, the lens unit 2 or the imaging unit 3 is moved in the Z-axis direction as the image magnification changes. In addition, the focus evaluation value calculation unit 130c can calculate the focus evaluation value without any problem.

  In the first to third embodiments described above, the position adjustment device for the imaging device including the measurement chart 1 in which a plurality of black square-shaped chart patterns 61 and 62 are printed on the chart surface has been described. The chart pattern is not limited to this, and may be a ladder-like chart pattern in which straight lines are arranged at a predetermined interval.

  Also, movement in the Z-axis direction, movement in the X-axis direction perpendicular to the Z-axis, movement in the Y-axis direction perpendicular to the Z-axis and the X-axis, rotation around the Z-axis, rotation around the X-axis, Although a 6-axis stage having a function of rotating around the Y axis is used as the moving mechanism 20, the inclination of the image pickup element held by the image pickup unit holding unit around the Z axis is within an allowable range. When the imaging unit can be held by the imaging unit holding unit, the moving mechanism may not have a function of rotating around the Z axis.

  Although specific embodiments of the present invention have been described, the present invention is not limited to the first to third embodiments, and various modifications can be made within the scope of the present invention.

In the prior art described in Patent Document 2 (Japanese Patent Laid-Open No. 2006-30256),
(1) A mechanism for exchanging the measurement chart is required (if the measurement chart is fixed, a moving mechanism is required).
(2) The operation accuracy of the mechanism is required when changing the measurement chart (positioning accuracy).
(3) Cost increases according to the number of measurement charts.
(4) Large equipment space (2 charts).
In contrast, the image sensor position adjustment apparatus of the present invention uses the same subject (measurement chart) for the focus and image sensor adjustment angle, both of which are adjusted with resolution. Since this resolution is substantially correlated with the blur of an actual photograph, a result close to an image seen by human eyes is obtained, and has the following features (a) to (d).
(a) Just adjust during assembly.
(b) There is no need to change the measurement chart.
(c) The cost for one measurement chart is sufficient.
(d) Space for one measurement chart is sufficient.

An image sensor position adjusting device according to the present invention includes:
A measurement chart 1 in which a plurality of chart patterns are formed;
A lens unit holding unit 11 for holding the lens unit 2 in which the taking lens 72 arranged on the Z-axis orthogonal to the measurement chart 1 is incorporated;
An imaging unit holding unit 20a for holding the imaging unit 3 in which the imaging element 82 arranged on the Z-axis is incorporated so as to capture the chart image of the measurement chart 1 formed by the imaging lens 72; ,
A moving mechanism 20 that moves either the lens unit holding unit 11 or the imaging unit holding unit 20a along the Z-axis direction;
Based on the chart image of the measurement chart imaged by the imaging element 82 while moving either the lens unit holding unit 11 or the imaging unit holding unit 20a along the Z-axis direction by the moving mechanism 20. A tilt adjusting unit 20b that adjusts the tilt around the Z-axis of the image sensor 82 and the tilt around the X-axis and the Y-axis intersecting the Z-axis,
The distance L between the measurement chart 1 and the photographic lens 72 is
200mm ≤ L ≤ 2000mm
It satisfies the following conditions.

  According to the above configuration, the measurement chart 1 can be arranged at a short distance from the photographing lens 72, and the apparatus main body can be downsized not only in the optical axis direction but also in the width direction and the depth direction.

  Further, the photographic lens 72 is moved to the subject side with respect to the position of the photographic lens 72 that forms an image of the subject at a position corresponding to infinity on the imaging surface of the imaging device 82, or the imaging device 82 is moved to the subject. The image sensor 82 can be tilted by widening the distance between the photographic lens 72 and the image sensor 82, and the adjustment angle of the image sensor 82 and the photographic lens 72 by active alignment is large. However, a sufficient margin for tilt adjustment can be ensured by a low-cost and space-saving image sensor position adjusting device.

In the image sensor position adjustment device of one embodiment,
The distance L between the measurement chart 1 and the photographic lens 72 is
400mm ≤ L ≤ 1000mm
Satisfy the condition of

In the image sensor position adjustment device of one embodiment,
A filling portion 40 for filling an adhesive into at least a part of the gap between the lens unit 2 and the photographing unit 3 is provided.

  According to the above embodiment, by filling at least a part of the gap between the lens unit 2 and the photographing unit 3 with the filling portion 40, the photographing unit 3 in which the gap between the lens unit 2 and the lens unit 2 varies after the tilt adjustment is obtained. It can be easily fixed to the unit 2.

In the image sensor position adjustment device of one embodiment,
The filling unit 40 is configured such that an ultraviolet curable adhesive or thermosetting is applied to at least a part of the gap before adjusting the angles around the X, Y, and Z axes of the image sensor 82 by the tilt adjusting unit 20b. Fill at least one of the mold adhesives.

  According to the above embodiment, at least a part of the gap between the lens unit 2 and the imaging unit 3 is filled with at least one of an ultraviolet curable adhesive or a thermosetting adhesive before adjustment by the inclination adjusting unit 20b. By filling with the unit 40, the adhesive between the lens unit 2 and the imaging unit 3 can be easily filled before the inclination of the imaging element 82 is adjusted, and the lens unit 2 and the imaging unit 3 are adjusted after the inclination adjustment. Even if there is a portion where the distance between the lens unit 2 and the imaging unit 3 is narrowed, the lens unit 2 and the imaging unit 3 can be reliably and easily bonded to each other by irradiating or heating the filled adhesive with ultraviolet rays.

In the image sensor position adjustment device of one embodiment,
Based on the chart image picked up by the image pickup element 82, X of the image pickup surface of the image pickup element 82 with respect to the image formation surface of the chart image formed by the photographing lens 72 using SFR (spatial frequency response). An inclination calculating unit 130a for calculating inclinations about the axis, the Y axis, and the Z axis;
The tilt adjusting unit 20b is configured to determine the X axis, Y axis, and Y axis of the image sensor 82 based on the tilts around the X axis, Y axis, and Z axis of the imaging surface of the image sensor 82 calculated by the tilt calculator 130a. Adjust the tilt around the Z axis.

  According to the above embodiment, the chart image formed on the imaging surface of the chart image 72 using the SFR (spatial frequency response) based on the chart images captured by the imaging element 82 at a plurality of Z coordinates with respect to the imaging plane. Since the inclination calculation unit 130a calculates the inclination of the image pickup surface of the image pickup element 82 about the X axis, the Y axis, and the Z axis, the focus evaluation can be performed with high accuracy even from a blurred image by SFR (spatial frequency response). The inclination of the imaging surface of the imaging element 82 relative to the imaging surface of the chart image formed by 72 can be accurately calculated around the X, Y, and Z axes.

DESCRIPTION OF SYMBOLS 1 ... Measurement chart 2 ... Lens unit 3 ... Imaging unit 10 ... Lens positioning jig 11 ... Lens holding mechanism 12, 21 ... Adsorption pad 13,14 ... Positioning pin 20 ... Moving mechanism 20a ... Imaging unit holding part 20b ... Inclination adjustment part DESCRIPTION OF SYMBOLS 30,130 ... Control apparatus 30a, 130a ... Inclination calculation part 40 ... Adhesive application apparatus 50 ... UV irradiation machine 61,62,63 ... Chart pattern 71 ... Unit main body 72 ... Shooting lens 73 ... VCM
81 ... Substrate 82 ... Image sensor 130b ... Chart pattern recognition unit 130c ... Focus evaluation value calculation unit

Claims (5)

A measurement chart in which a plurality of chart patterns are formed;
A lens unit holding unit for holding a lens unit in which a photographing lens arranged on the Z axis orthogonal to the measurement chart is incorporated;
An imaging unit holding unit for holding an imaging unit in which an imaging element arranged on the Z-axis is incorporated so as to capture a chart image of the measurement chart formed by the imaging lens;
A moving mechanism for moving either the lens unit holding unit or the imaging unit holding unit along the Z-axis direction;
Based on the chart image of the measurement chart imaged by the imaging device while moving either the lens unit holding unit or the imaging unit holding unit along the Z-axis direction by the moving mechanism, the imaging device An inclination adjustment unit for adjusting the inclination about the Z axis and the inclination about the X axis and the Y axis intersecting with the Z axis,
The distance L between the measurement chart and the photographic lens is
200mm ≤ L ≤ 2000mm
An image sensor position adjusting device characterized by satisfying the following condition. In the image sensor position adjusting device according to claim 1,
The distance L between the measurement chart and the photographic lens is
400mm ≤ L ≤ 1000mm
An image sensor position adjusting device characterized by satisfying the following condition. In the position adjustment device of the image sensor according to claim 1 or 2,
An image sensor position adjusting device comprising: a filling unit that fills at least a part of a gap between the lens unit and the photographing unit. In the position adjustment device of the image sensor according to claim 3,
The filling unit is configured to attach an ultraviolet curable adhesive or a thermosetting adhesive to at least a part of the gap before adjusting the angles around the X axis, the Y axis, and the Z axis of the imaging element by the inclination adjusting unit. An image sensor position adjusting device, wherein at least one of the agents is filled. In the position adjustment device of the image sensor according to any one of claims 1 to 4,
Based on the chart image picked up by the image pickup device, the X axis of the image pickup surface of the image pickup device with respect to the image formation surface of the chart image formed by the photographing lens using SFR (spatial frequency response), Y An inclination calculation unit for calculating the inclination about the axis and the Z axis;
The tilt adjustment unit is configured to rotate around the X axis, Y axis, and Z axis of the image sensor based on the tilt around the X axis, Y axis, and Z axis of the imaging surface of the image sensor calculated by the tilt calculation unit. An apparatus for adjusting the position of an image sensor, characterized by adjusting an inclination.

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