METHOD FOR ADJUSTING POSITION OF IMAGE SENSOR, METHOD AND APPARATUS FOR MANUFACTURING A CAMERA MODULE, AND CAMERA MODULE
First Claim
1. A method for adjusting position of an image sensor comprising:
- (A) an in-focus coordinate value obtaining step including steps of;
placing a taking lens and an image sensor for capturing a chart image formed by said taking lens on a Z axis orthogonal to a measurement chart;
capturing said chart image while moving said taking lens or said image sensor sequentially to a plurality of discrete measurement positions previously established on said Z axis;
calculating a focus evaluation value indicating a degree of focus at each said measurement positions in plural imaging positions based on image signals obtained in at least five said imaging positions on an imaging surface of said image sensor; and
obtaining a Z axis coordinate of the measurement position providing a predetermined focus evaluation value as an in-focus coordinate value for each of said imaging positions;
(B) an imaging plane calculating step including steps of;
transforming at least five evaluation points in a three dimensional coordinate system composed of an XY coordinate plane orthogonal to said Z axis, each of said evaluation points being expressed by a combination of XY coordinate values of said imaging positions, obtained when said imaging surface overlaps with said XY coordinate plane, and said in-focus coordinate values on said Z axis of said imaging positions; and
calculating an approximate imaging plane defined as a single plane in said three dimensional coordinate system based on the relative position of said evaluation points;
(C) an adjustment value calculating step for calculating an imaging plane coordinate value representing an intersection point between said approximate imaging plane and said Z axis, and rotation angles of said approximate imaging plane around an X axis and an Y axis with respect to said XY coordinate plane; and
(D) an adjusting step for adjusting position on said Z axis and tilt around said X and Y axes of said image sensor based on said imaging plane coordinate value and said rotation angles so that said imaging surface overlaps with said approximate imaging plane.
1 Assignment
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Accused Products
Abstract
A lens unit and a sensor unit are held by a lens holding mechanism and a sensor shift mechanism. As the sensor unit is moved in a Z axis direction on a second slide stage, a chart image is captured with an image sensor through a taking lens so as to obtain in-focus coordinate values in at least five imaging positions on an imaging surface. An approximate imaging plane is calculated from the relative position of plural evaluation points which are defined by transforming the in-focus coordinate value of each imaging position in a three dimensional coordinate system. The second slide stage and a biaxial rotation stage adjust the position and tilt of the sensor unit so that the imaging surface overlaps with the approximate imaging plane.
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Citations
26 Claims
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1. A method for adjusting position of an image sensor comprising:
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(A) an in-focus coordinate value obtaining step including steps of; placing a taking lens and an image sensor for capturing a chart image formed by said taking lens on a Z axis orthogonal to a measurement chart; capturing said chart image while moving said taking lens or said image sensor sequentially to a plurality of discrete measurement positions previously established on said Z axis; calculating a focus evaluation value indicating a degree of focus at each said measurement positions in plural imaging positions based on image signals obtained in at least five said imaging positions on an imaging surface of said image sensor; and obtaining a Z axis coordinate of the measurement position providing a predetermined focus evaluation value as an in-focus coordinate value for each of said imaging positions; (B) an imaging plane calculating step including steps of; transforming at least five evaluation points in a three dimensional coordinate system composed of an XY coordinate plane orthogonal to said Z axis, each of said evaluation points being expressed by a combination of XY coordinate values of said imaging positions, obtained when said imaging surface overlaps with said XY coordinate plane, and said in-focus coordinate values on said Z axis of said imaging positions; and calculating an approximate imaging plane defined as a single plane in said three dimensional coordinate system based on the relative position of said evaluation points; (C) an adjustment value calculating step for calculating an imaging plane coordinate value representing an intersection point between said approximate imaging plane and said Z axis, and rotation angles of said approximate imaging plane around an X axis and an Y axis with respect to said XY coordinate plane; and (D) an adjusting step for adjusting position on said Z axis and tilt around said X and Y axes of said image sensor based on said imaging plane coordinate value and said rotation angles so that said imaging surface overlaps with said approximate imaging plane. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus for manufacturing a camera module comprising:
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a measurement chart having a chart pattern; a lens unit holder for holding a lens unit having a taking lens and for placing said lens unit on a Z axis orthogonal to said measurement chart; a sensor unit holder for holding a sensor unit having an image sensor so as to place said sensor unit on said Z axis, and for changing position of said sensor unit on said Z axis and tilt of said sensor unit around X and Y axes orthogonal to said Z axis; a measurement position changer for moving said lens unit holder or said sensor unit holder so that said taking lens or said sensor unit is placed sequentially to a plurality of discrete measurement positions previously established on said Z axis; a sensor controller for controlling said image sensor to capture a chart image formed by said taking lens at each of said measurement positions; an in-focus coordinate obtaining device for calculating a focus evaluation value indicating a degree of focus at each said measurement positions in plural imaging positions based on image signals obtained in at least five said imaging positions on an imaging surface of said image sensor, and for obtaining a Z axis coordinate of the measurement position providing a predetermined focus evaluation value as an in-focus coordinate value for each of said imaging positions; an imaging plane calculating device for transforming at least five evaluation points in a three dimensional coordinate system composed of an XY coordinate plane orthogonal to said Z axis, each of said evaluation points being expressed by a combination of XY coordinate values of said imaging positions, obtained when said imaging surface overlaps with said XY coordinate plane, and said in-focus coordinate values on said Z axis of said imaging positions, and for calculating an approximate imaging plane defined as a single plane in said three dimensional coordinate system based on the relative position of said evaluation points; an adjustment value calculating device for calculating an imaging plane coordinate value representing an intersection point between said approximate imaging plane and said Z axis, and rotation angles of said approximate imaging plane around an X axis and an Y axis with respect to said XY coordinate plane; and an adjuster for driving said sensor unit holder based on said a imaging plane coordinate value and said rotation angles around said X and Y axes so as to adjust position of said image sensor on said Z axis and tilt of said image sensor around said X and Y axes until said imaging surface overlaps said approximate imaging plane. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A camera module including a lens unit having a taking lens and a sensor unit having an image sensor for capturing an object image formed through said taking lens, said sensor unit being fixed to said lens unit after being adjusted in position to said lens unit, position adjustment of said sensor unit comprising:
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(A) an in-focus coordinate value obtaining step including steps of; placing a taking lens and an image sensor for capturing a chart image formed by said taking lens on a Z axis orthogonal to a measurement chart; capturing said chart image while moving said taking lens or said image sensor sequentially to a plurality of discrete measurement positions previously established on said Z axis; calculating a focus evaluation value indicating a degree of focus at each said measurement positions in plural imaging positions based on image signals obtained in at least five said imaging positions on an imaging surface of said image sensor; and obtaining a Z axis coordinate of the measurement position providing a predetermined focus evaluation value as an in-focus coordinate value for each of said imaging positions; (B) an imaging plane calculating step including steps of; transforming at least five evaluation points in a three dimensional coordinate system composed of an XY coordinate plane orthogonal to said Z axis, each of said evaluation points being expressed by a combination of XY coordinate values of said imaging positions, obtained when said imaging surface overlaps with said XY coordinate plane, and said in-focus coordinate values on said Z axis of said imaging positions; and calculating an approximate imaging plane defined as a single plane in said three dimensional coordinate system based on the relative position of said evaluation points; (C) an adjustment value calculating step for calculating an imaging plane coordinate value representing an intersection point between said approximate imaging plane and said Z axis, and rotation angles of said approximate imaging plane around an X axis and an Y axis with respect to said XY coordinate plane; and (D) an adjusting step for adjusting position on said z axis and tilt around said X and Y axes of said image sensor based on said imaging plane coordinate value and said rotation angles so that said imaging surface overlaps with said approximate imaging plane. - View Dependent Claims (22, 23, 24, 25, 26)
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Specification