JP2014182354A - Lens inclination detection apparatus and lens inclination detection method - Google Patents

Abstract

A lens tilt detection apparatus and a lens tilt detection method capable of accurately detecting the tilt of an optical axis of a lens even in a state of an optical unit in which the lens is incorporated in a holder.
A plurality of point light sources 21 arranged on a plane orthogonal to a reference axis m and spaced from each other and irradiating light to a lens to be measured arranged on the reference axis m, and a plurality of point light sources 21 A plurality of point light sources 21 which are arranged on the side opposite to the lens L1 to be measured and the optical axis coincides with the reference axis m, and are generated by reflected light from a plurality of lens surfaces of the lens L1 to be measured. Based on the relative shift amounts of the center positions of the imaging images 3 of the imaging images 3 and the plurality of imaging images of the plurality of point light sources 21 captured by the imaging camera 3 with respect to the direction of the reference axis m. A lens tilt detector (4, 5, 6) for detecting the tilt angle and tilt direction of the optical axis of the lens L1 to be measured is provided.
[Selection] Figure 1

Description

  The present invention relates to a lens tilt detection apparatus and a lens tilt detection method, and relates to a lens tilt detection apparatus and a lens tilt detection method used for lens tilt adjustment of an optical communication lens, an imaging system lens, an optical disk lens, and the like.

  In a camera module for a mobile phone, due to a compact imaging device and diversification of aspherical lenses, strict positioning adjustment accuracy is required when the lens is incorporated into an optical unit.

  Therefore, as a conventional lens tilt detection device, there is a device that adjusts the tilt by irradiating illumination light to the lens and converting the lens tilt angle with respect to the reference surface of the lens holder from the deviation of the reflected image of the lens surface (for example, a special feature). No. 2010-54677 (see Patent Document 1).

JP 2010-54677 A

  By the way, the lens becomes an optical unit on which an actuator for driving the lens is mounted after being incorporated in the lens unit. At this time, the lens is often tilted and adjusted with respect to the reference plane of the optical unit, and the lens is tilted with respect to the optical axis of the optical unit, and this optical unit is attached to the image sensor without adjustment. However, a camera module having desired performance cannot be obtained. Therefore, it is necessary to measure the tilt of the lens in the state of the optical unit and adjust the generated tilt.

  By using the above-described lens tilt detection technique, the tilt angle of the optical axis of the lens with respect to the holder into which the lens is assembled can be adjusted. The lens tilt reference is set to the lens outer shape or the inner diameter of the holder in contact with the lens. There is a need. For this reason, in the state of the optical unit already incorporated in the holder in which these cannot be seen, there is a problem that the tilt of the lens cannot be measured accurately and the optical unit cannot be incorporated into the image sensor and adjusted.

  In view of the above problems, an object of the present invention is to provide a lens tilt detection device and a lens tilt detection method capable of accurately detecting the tilt of the optical axis of a lens even in a state of an optical unit in which a lens is incorporated in a holder. Is.

In order to solve the above problems, a lens tilt detection device of the present invention is
A plurality of point light sources arranged on the same plane perpendicular to the reference axis and spaced from each other, and irradiating light to the lens to be measured arranged on the reference axis;
It is arranged so that the optical axis coincides with the reference axis on the side opposite to the lens to be measured with respect to the plurality of point light sources, and is generated by reflected light from a plurality of lens surfaces of the lens to be measured. An imaging camera that captures a plurality of formed images of the point light source;
An inclination angle of the optical axis of the lens to be measured with respect to the reference axis direction based on the relative shift amount of the center position of each of the plurality of formed images of the plurality of point light sources captured by the imaging camera; And a lens tilt detection unit for detecting the tilt direction.

Moreover, in the lens tilt detection device of one embodiment,
The plurality of point light sources are arranged at the vertices of a plurality of polygons.

Moreover, in the lens tilt detection device of one embodiment,
A light source controller that controls one or more point light sources among the plurality of point light sources so as to be lit at an arbitrary timing is provided.

In the lens tilt detection method of the present invention,
A plurality of lenses of the measurement target lens are irradiated with light from a plurality of point light sources arranged on a plane orthogonal to the reference axis at intervals from each other, and irradiated to the measurement target lens arranged on the reference axis. Capturing an image of the reflected light of the first surface of the surface by an imaging camera that forms an image with an imaging system in which the optical axis coincides with the reference axis;
Obtaining a center position of the reflected light image of the first surface imaged by the imaging camera by a center position calculation unit;
Forming an image of reflected light from another lens surface different from the first surface of the lens with the imaging system, and imaging with the imaging camera;
Obtaining a center position of an image of reflected light from another lens surface different from the first surface of the lens imaged by the imaging camera by the center position calculating unit;
Based on the center position of the reflected light image on the first surface and the center position of the reflected light image from another lens surface different from the first surface, which is obtained by the center position calculation unit, with respect to the reference axis direction. And a step of calculating a tilt angle and a tilt direction of the optical axis of the lens by a lens tilt calculator.

  As is clear from the above, according to the present invention, the light of the lens to be measured is based on the relative shift amounts of the respective center positions of the plurality of formed images of the plurality of point light sources captured by the imaging camera. Realizing a lens tilt detection device and a lens tilt detection method capable of accurately detecting the tilt of the optical axis of a lens even in the state of an optical unit in which the lens is incorporated in a holder by detecting the tilt angle and tilt direction of the shaft Can do.

FIG. 1 is a diagram showing a schematic configuration of a lens tilt detection apparatus according to a first embodiment of the present invention. FIG. 2A is a schematic view of a light source in which LEDs as an example of a point light source are arranged so as to be at the apex of a quadrangle in the lens tilt detection apparatus. FIG. 2B is a schematic cross-sectional view of an optical unit in which the lens tilt is detected by the lens tilt detection device. FIG. 3A is a diagram showing the relationship between the eccentricity generated when the lens of the optical unit is tilted and the image. FIG. 3B is a diagram showing a virtual image due to light diverging and reflecting from the upper surface of the convex meniscus lens and a virtual image due to light diverging and reflecting from the upper surface of the lens and from the lower surface. FIG. 3C is a diagram showing a real image by light converged and reflected by the upper surface of the concave meniscus lens and a real image by light that has passed through the upper surface of the lens and converged and reflected by the lower surface. FIG. 3D is a diagram showing a real image by light converged and reflected on the upper surface of the biconcave lens, and a virtual image by light diverged and reflected by the lower surface through the upper surface of the lens. FIG. 3E shows an image when the first lens is a biconvex lens and the second lens is a concave meniscus lens. FIG. 4A is a diagram illustrating an image of a light source when the lens is not inclined. FIG. 4B is a diagram illustrating a state of an image of the light source when the lens holder is rotated counterclockwise. FIG. 4C is a diagram showing a state of an image of a light source when the lens holder is rotated clockwise. FIG. 5A is a diagram illustrating a state of an image of a light source when the aperture of the lens holder is formed so as to be shifted from the center of the lens. FIG. 5B is a diagram showing a state of an image of a light source when the lens holder is rotated counterclockwise. FIG. 5C is a diagram showing a state of an image of a light source when the lens holder is rotated clockwise. FIG. 6A is a diagram for explaining the measurement of the tilt amount of the light receiving surface of the image sensor. FIG. 6B is a diagram for explaining the measurement of the tilt amount of the optical unit using the lens tilt detection apparatus. FIG. 6C is a diagram for describing a product inspection in which an imaging chart is captured to confirm imaging characteristics. FIG. 7A is a schematic diagram of a light source in which LEDs of a lens tilt detection apparatus according to a second embodiment of the present invention are arranged so as to be at the apexes of a quadrangular shape and a pentagonal shape. FIG. 7B is a schematic diagram of the light source when only the point light source arranged at the apex of the quadrangular is turned on. FIG. 7C is a schematic diagram of the light source when only the point light source arranged at the vertex of the pentagon is turned on. FIG. 8A is a diagram showing an image of the light source when the lens is not inclined in the configuration of the light source in which the point light sources are arranged in a square shape shown in FIG. 7B. FIG. 8B is a diagram showing a state of an image of the light source when the lens holder is rotated counterclockwise in the light source when only the point light source arranged at the vertex of the rectangle shown in FIG. 7B is turned on. FIG. 8C is a diagram showing a state of an image of the light source when the lens holder is rotated counterclockwise in the light source when only the point light source arranged at the vertex of the pentagon shown in FIG. 7C is turned on. FIG. 9A is a diagram showing a state of an image of the light source of the first example in which only a designated portion of each point light source is turned on. FIG. 9B is a diagram showing a state of an image of the light source of the second example in which only a designated portion of each point light source is turned on. FIG. 9C is a diagram showing a state of an image of the light source of the third example in which only a designated portion of each point light source is turned on. FIG. 9D is a diagram illustrating a state of an image of the light source of the fourth example in which only a designated portion of each point light source is turned on.

  Hereinafter, a lens tilt detection apparatus and a lens tilt detection method according to the present invention will be described in detail with reference to embodiments shown in the drawings.

[First Embodiment]
FIG. 1 shows a schematic configuration of a lens tilt detection apparatus according to a first embodiment of the present invention.

  As shown in FIG. 1, the lens tilt detection apparatus 1 according to the first embodiment includes a light source 2, an imaging camera 3, a signal processing unit 4, an image processing unit 5, an arithmetic processing unit 6, and a display unit 7. And. The signal processing unit 4, the image processing unit 5 and the arithmetic processing unit 6 constitute a lens tilt detection unit.

  As shown in FIG. 2A, the light source 2 is a light source in which a plurality of LEDs (Light Emitting Diodes) 21 as an example of a point light source are arranged, and is orthogonal to the reference axis (the optical axis m of the imaging camera 3). The four LEDs 21 are arranged on the same plane so as to be the apexes of the quadrangle. In addition, the light emitting element used for this light source 2 is not restricted to LED, A fluorescent tube, a light bulb, a laser beam, EL (Electro Luminescence: EL) may be used. Moreover, the number and arrangement of the LEDs may be different.

  Further, as shown in FIG. 2B, the optical unit 10 drives a lens group 41 (three-lens configuration in FIG. 1), a lens holder 42 to which the lens group 41 is attached, and the lens holder 42 up and down. The actuator 43 for this is comprised.

  The light from the light source 2 is applied to the optical unit 10 as shown in FIG. The light from the light source 2 forms an image reflected by the upper surface S1 and an image reflected by the lower surface S2 of the first lens L1 of the lens group 41. The imaging camera 3 causes the lens unit 31 to make this image incident on a CCD (Charge Coupled Device) 32 that is a light receiving element. The lens unit 31 is an imaging system that forms an image of the reflected light of the lens group 41 of the optical unit 10.

  The light source 2 irradiates light to the optical unit 10 side, but does not irradiate light to the imaging camera 3 side.

  On the imaging surface of the CCD 32, an image of the light source 2 reflected by the upper surface S1 and the lower surface S2 of the first lens L1 is captured. The shape of the image of the light source 2 is determined based on the positional relationship among the CCD 32, the lens unit 31, the light source 2, the first lens L 1, and the specification settings of the imaging camera 3.

  The output signal from the CCD 32 is sent to the signal processing unit 4, which generates a video signal corresponding to the light intensity of the received image and transmits it to the image processing unit 5. Then, the image processing unit 5 converts the received video signal into an image signal. The signal processing unit 4 may be provided in the CCD 32 or in the arithmetic processing unit 6. The image signal converted by the image processing unit 5 is output to an arithmetic processing unit 6 composed of a microcomputer, and the arithmetic processing unit 6 obtains the center position of the image.

  The arithmetic processing unit 6 includes a center position calculation unit 6a for determining the center position of the image of the reflected light from the first lens L1 captured by the imaging camera 3, and the image of the reflected light determined by the center position calculation unit 6a. And a lens tilt calculator 6b that calculates the tilt of the first lens L1 based on the center position.

  Note that the center of the image light intensity or the like may be obtained from the positional relationship of the point light sources by the calculation of the image processing unit 5, or a specific position other than the center position or the center of gravity may be obtained.

  When obtaining the center of gravity, a PSD (Position Sensitive Device) may be used instead of the CCD 32. In this case, a signal processing unit that processes an output signal of the PSD is used instead of the image processing unit 5.

  The arithmetic processing unit 6 calculates the inclination (inclination angle and inclination direction) of the first lens L1 by performing arithmetic processing based on the output signal of the CCD 32.

  Then, the image and calculation result obtained by the calculation processing unit 6 are displayed on the display unit 7. The display unit 7 employs a liquid crystal display or a CRT display.

  Further, the lens group 41 composed of a plurality of first to third lenses L1, L2, and L3 is normally assembled with high-precision tilt adjustment. In particular, the first lens L1 is often a lens that greatly affects the optical performance. Therefore, the inclination of the optical axis of the first lens L1 affects the optical performance of the lens group 41.

  Therefore, a lens tilt detection method for detecting the tilt (tilt angle and tilt direction) of the first lens L1 to be used as an index for tilt adjustment of the lens group 41 will be described in detail. This lens tilt detection method obtains the state of eccentricity that occurs when the first lens L1 tilts, and detects the tilt (tilt angle and tilt direction) of the first lens L1.

  The relationship between the decentering of the first lens L1 and the image will be described with reference to FIGS. 3A to 3D.

  First, as shown in FIG. 3A, when the first lens L1 is a biconvex lens, the light emitted from the light source 2 is first divergently reflected by the upper surface S1 of the first lens L1, and the imaging camera is applied to the first lens L1. A virtual image is formed at a point P1 on the opposite side to 3. Next, the light transmitted through the upper surface S1 of the first lens L1 and converged and reflected by the lower surface S2 forms a real image at a point P2 on the imaging camera 3 side with respect to the first lens L1. When images taken at these points P1 and P2 are observed by the imaging camera 3, an image is formed at a point P1 on the opposite side (back side) of the light source 2 with respect to the first lens L1, and the light source with respect to the first lens L1. An image is formed at the point P2 on the second side (near side).

  At this time, it is desirable that the depth of field of the imaging camera 3 is such that only the points P1 to P2 are observed simultaneously. However, even if the depth of field is not sufficient from the point P1 to the point P2, there is no problem as long as an image capable of measuring the center of the image is obtained.

  Further, as shown in FIG. 3B, when the first lens L1 is a convex meniscus lens as viewed from the illumination side, the light emitted from the light source 2 is first divergently reflected by the upper surface S1 of the first lens L1, and is reflected at the point P1. You can make a virtual image. Next, the light transmitted through the upper surface S1 of the first lens L1 is divergently reflected by the lower surface S2 of the first lens L1, and forms a virtual image at the point P2. When images taken at these points P1 and P2 are observed by the imaging camera 3, images are formed at points P1 and P2 on the opposite side (back side) of the light source 2 with respect to the first lens L1.

  The positional relationship between the point P1 and the point P1 in the direction along the optical axis m is determined by the curvature of the lens surfaces (S1, S2) of the first lens L1, but is not important in the present invention.

  Further, as shown in FIG. 3C, when the first lens L1 is a concave meniscus lens as viewed from the illumination side, the light emitted from the light source 2 is first converged and reflected by the upper surface S1 of the first lens L1, and is reflected at the point P1. Real image is possible. Next, the light transmitted through the upper surface S1 of the first lens L1 is converged and reflected by the lower surface S2 of the first lens L1, and forms a real image at the point P2. When images formed at these points P1 and P2 are observed by the imaging camera 3, images are formed at points P1 and P2 on the light source 2 side (near side) with respect to the first lens L1.

  As shown in FIG. 3D, when the first lens L1 is a biconcave lens, the light emitted from the light source 2 is first converged and reflected by the upper surface S1 of the first lens L1, and a real image is formed at the point P1. Next, the light transmitted through the upper surface S1 of the first lens L1 is divergently reflected by the lower surface S2 of the first lens L1, and forms a virtual image at the point P2. When images formed at these points P1 and P2 are observed by the imaging camera 3, an image is formed at a point P1 on the light source 2 side (near side) with respect to the first lens L1, and opposite to the light source 2 with respect to the first lens L1. An image is formed at the point P2 on the back side (back side). In this manner, a reflection elephant from the front and back surfaces of one lens is formed on the optical axis m regardless of the shape of the lens.

  In addition, even when there are a plurality of lenses other than the first lens L1, an image by reflected light from the surface of each lens is generated, and an image within the depth of field can be observed by the imaging camera 3.

  For example, as shown in FIG. 3E, when the first lens L1 is a biconvex lens and the second lens L2 is a concave meniscus lens, an image of the light source 2 is generated at points P1 to P4.

  In FIG. 3E, when the first lens L1 is a convex lens, the light emitted from the light source 2 is first divergently reflected by the upper surface S1 of the first lens L1, and a virtual image is formed at the point P1. Next, the light transmitted through the upper surface S1 of the first lens L1 is converged and reflected by the lower surface S2 of the first lens L1, and forms a real image at the point P2. Further, the light transmitted through the first lens L1 converges and reflects on the upper surface S1 of the second lens L2, passes through the first lens L1, and forms a real image at the point P3. The light transmitted through the second lens L2 is converged and reflected by the lower surface S4 of the second lens L2, passes through the first lens L1, and forms a real image at the point P4.

  At this time, the depth of field W of the imaging camera 3 may be designed so that all images of P1 to P4 can be observed at one time, but a design capable of observing at least two images is desirable (in FIG. 3E, W is Design example in which two points P1 and P2 can be observed at once).

  Further, when the depth of field W is small and two or more points cannot be observed at a time, the imaging camera 3 may focus on each image point sequentially and observe sequentially.

  Next, FIG. 4A, FIG. 4B, and FIG. 4C show the state when these illumination images are lens-tilted. 4A, 4B, and 4C, an image obtained by the CCD 32 (shown in FIG. 1) is shown in the upper part of the drawing, and the inclination state of the optical axes of the lens holder 42 and the first lens L1 is schematically shown in the lower part of the drawing. Shown in the figure.

  FIG. 4A shows a case where the first lens L1 is not tilted. In the image obtained by the CCD 32 at this time, the images R1 and R2 of the light source 2 (points P1 and P2 representing the center position) appear at the vertices of the square.

  From this state, as shown in FIG. 4B, when the lens holder 42 is rotated in the direction W1 (counterclockwise), the points P1 and P2 representing the center positions of the images R1 and R2 of the light source 2 are left and right in the drawing. Observed.

  Next, as shown in FIG. 4C, when the lens holder 42 is rotated in the direction of W2 (clockwise), the points P1 and P2 representing the center positions of the images R1 and R2 of the light source 2 are reversed in the horizontal direction in the figure. Observed.

  As described above, when the first lens L1 is tilted, the optical surfaces (S1, S2) are decentered, and the decentered state is an image obtained by the imaging camera 3 (a point P1 representing the center position of the images R1, R2). , P2) can be detected from the relative positional relationship, and the tilt angle, tilt direction, and the like of the optical axis of the first lens L1 with respect to the optical axis m direction can be obtained by back calculation from the detected eccentric state.

  That is, by detecting the shift direction of the points P1 and P2 representing the center positions of the images R1 and R2 of the light source 2 from the image of the CCD 32, the inclination direction of the optical axis of the first lens L1 with respect to the optical axis m direction can be detected. By detecting the distance between the points P1 and P2 representing the center position of the image of the light source 2, the inclination angle of the optical axis of the first lens L1 with respect to the optical axis m direction can be detected.

  Therefore, the tilt correction of the first lens L1 can be performed by adjusting the images R1 and R2 of the light source 2 so that they are concentric and the points P1 and P2 representing the center position overlap.

  This is because the inclination angle of the optical axis of the first lens L1 is detected by detecting the relative positional relationship between two or more images of the lens, and therefore the first mounted on the optical unit 10 where the lens outer shape cannot be seen. This is effective for the lens L1.

  Further, even when the aperture AP of the lens holder 42 is displaced from the center of the first lens L1 as shown in FIG. 5A, the images R1 and R2 are concentrically centered without being affected by the influence. When the points P1 and P2 representing the position overlap, it can be determined that there is no lens tilt.

  On the other hand, as shown in FIG. 5B, when the lens holder 42 is rotated in the direction W1 (counterclockwise), points P1 and P2 representing the center position of the image of the light source 2 are shown in the figure regardless of the position of the aperture AP. Observed from left to right.

  Next, as shown in FIG. 5C, when the lens holder 42 is rotated in the direction W2 (clockwise), the points P1 and P2 representing the center position of the image of the light source 2 are shifted and observed in the opposite directions in the figure. Is done.

  As described above, when the first lens L1 is tilted, the optical surfaces (S1, S2) are decentered, and the decentered state can be detected from the relative positional relationship of the obtained image. The angle of inclination of the optical axis of the first lens L1 with respect to the optical axis m direction can be obtained by calculating backward from the above state.

  That is, by detecting the shift direction of the points P1 and P2 representing the center positions of the images R1 and R2 of the light source 2 from the image of the CCD 32, the inclination direction of the optical axis of the first lens L1 with respect to the optical axis m direction can be detected. By detecting the distance between the points P1 and P2 representing the center positions of the images R1 and R2 of the light source 2, the inclination angle of the optical axis of the first lens L1 with respect to the optical axis m direction can be detected.

  In the first embodiment, the description is given with the reflected image of only the first lens L1, but the same applies to the case where two or more images are obtained in the optical unit including two or more lenses. The state where the images are concentric is a state where there is no lens tilt. The tilt angle is detected by the sum of the differences between the center positions of the images, and the tilt direction is detected by detecting the direction in which each image is decentered when the tilt occurs. Can be recognized.

  Next, assembling of an imaging camera module that implements the lens tilt detection method of the present invention using the lens tilt detection apparatus shown in FIG. 1 will be described. The assembly flow of the imaging camera module is executed by an instruction from a program in the arithmetic processing unit 6 (shown in FIG. 1). This program is stored in a ROM (Read Only Memory) or RAM (Random Access Memory) (not shown) in the arithmetic processing unit 6.

  As shown in FIG. 6A, first, an imaging sensor 9 for a camera module is set in an assembly device (not shown), and a reference axis (optical axis) is set by a tilt sensor 20 arranged on an assembly reference axis (optical axis m) of the assembly device. The tilt amount (tilt angle) α1 of the light receiving surface of the image sensor 9 with respect to m) is measured.

  Next, as shown in FIG. 6B, the optical unit 10 for the camera module is set in the assembling apparatus, and the lens inclination detecting apparatus 1 of the first embodiment arranged on the assembling reference axis (optical axis m) of the assembling apparatus, The tilt amount (tilt angle) α2 of the lens group 41 with respect to the reference axis (optical axis m) is measured.

According to the above measurement results, (1) As a camera module, the image sensor 9 is corrected from the tilt amount α1 to the tilt amount α2 of the lens group 41, the relative position is adjusted to the optical unit 10, and then the camera module is assembled. Assemble,
Alternatively, (2) the optical unit 10 is corrected from the tilt amount α2 to the tilt amount α1 of the image sensor and the relative position is adjusted to the image sensor 9, and then assembled to assemble the camera module.
Alternatively, (3) the posture of the optical unit 10 is adjusted so that the tilt amount α1 of the imaging sensor 9 is zero with respect to the reference axis (optical axis m) and the tilt amount α2 of the lens group 41 is zero. After the correction and the relative position adjustment between the corrected image sensor 4 and the optical unit 10, the camera module is assembled by assembling.

  With respect to the camera module assembled by any one of the above (1), (2), (3), the reference axis (light) as shown in FIG. 6C (the figure is assembled by the method of (1) above). An imaging chart C arranged perpendicular to the axis m) is imaged to confirm imaging characteristics and perform product inspection.

  In this way, if the tilt amount (tilt angle) of the lens group 41 can be measured in advance, the camera module can be assembled by correcting the tilt amount, and the camera module that becomes defective due to the lens tilt can be assembled. It is possible to reduce the manufacturing cost.

  According to the lens tilt detection device and the lens tilt detection method of the first embodiment, based on the relative shift amounts of the center positions of the plurality of formed images of the plurality of LEDs 21 captured by the imaging camera 3, By detecting the tilt angle and the tilt direction of the optical axis of the first lens L1 to be measured with respect to the reference axis m direction, even if the first lens L1 to be measured is tilted, the light of the first lens L1 to be measured The inclination of the axis can be detected accurately.

[Second Embodiment]
7A to 7C show the light source 2 in which the LEDs 21 of the lens tilt detection apparatus according to the second embodiment of the present invention are arranged so as to be at the apexes of the quadrangular shape and the pentagonal shape. The lens tilt detection device of the second embodiment has the same configuration as the lens tilt detection device of the first embodiment except for the light source 102, and FIG.

  In the lens tilt detection device of the second embodiment, as shown in FIG. 7A, in the light source 102 in which the LEDs 21 are arranged to be the apexes of the quadrangular and pentagon, a plurality of LEDs 21 are arranged at the apexes of the quadrangular. The LED group and the LED group in which a plurality of LEDs 21 are arranged at the apex of the pentagon can be turned on separately. Here, the on / off of the LED 21 of the light source 102 is controlled by the arithmetic processing unit 6 (shown in FIG. 1) including a light source control unit, but a control unit having a function of controlling the light source may be provided separately.

  Note that the light-emitting element used for the light source 102 is not limited to the LED, and may be a fluorescent tube, a light bulb, a laser beam, an EL, or the like. Further, the number and arrangement of the respective LEDs may be different.

  In the configuration in which only the LED group in which the LEDs 21 are arranged at the apexes of the square is turned on as in the light source 102 shown in FIG. 7B, the image is formed by reflecting the light on the upper surface of the lens and the light is reflected on the lower surface. When the formed images are extremely close to each other or when the images partially overlap, the coordinates of the images may not be detected accurately. On the other hand, as shown in FIG. 7C, by changing to a configuration in which only the LED group in which the LEDs 21 are arranged at the vertices of the pentagon is turned on, overlapping can be prevented and accurate detection can be performed.

  In the light source 102, the LEDs 21 are arranged on the same plane orthogonal to the reference axis (optical axis m) so as to be the apexes of the quadrangular and pentagonal shapes.

  As described above, according to the lens tilt detection apparatus of the second embodiment, it is possible to prevent a decrease in detection accuracy due to approaching or overlapping of images by using a plurality of lighting shapes of point light sources.

  FIG. 8A shows an illumination image when the first lens L1 is not tilted in the configuration of the light source 102 shown in FIG. 7B. FIG. 8B shows the lens holder 42 in the configuration of the light source 102 shown in FIG. The state of the illumination image when rotated clockwise is shown.

  As shown in FIG. 8A, in the light source 102 in the lit state shown in FIG. 7B, the image obtained by the CCD 32 (shown in FIG. 1) has images R1 and R2 of the light source 102 at square positions with respect to the lens holder 42. (Points P1 and P2 representing the center position) appear.

  From this state, as shown in FIG. 8B, when the lens holder 42 is rotated in the direction W1 (counterclockwise), the points P1 and P2 representing the center positions of the images R1 and R2 of the light source 102 are left and right in the figure. Observed.

  FIG. 8C shows an illumination image when the lens holder 42 is rotated counterclockwise in the light source 102 in the lit state shown in FIG. 7C.

  As shown in FIG. 8C, when the lens holder 42 is rotated in the direction of W1 (counterclockwise), the points P1 and P2 representing the center positions of the images R1 and R2 of the light source 102 are observed shifted to the left and right in the drawing. The

  As described above, when the first lens L1 is tilted, the optical surface is decentered, and the decentered state is relative to the images (points P1, P2 representing the center positions of the images R1, R2) obtained by the imaging camera 3. Since it can be detected from the positional relationship, it is possible to calculate the tilt angle, tilt direction, and the like of the optical axis of the first lens L1 with respect to the optical axis m direction by performing backward calculation from the detected eccentric state.

  That is, by detecting the shift direction of the points P1 and P2 representing the center positions of the images R1 and R2 of the light source 102 from the image of the CCD 32, the inclination direction of the optical axis of the first lens L1 with respect to the optical axis m direction can be detected. By detecting the distance between the points P1 and P2 representing the center position of the image of the light source 102, the tilt angle of the optical axis of the first lens L1 with respect to the optical axis m direction can be detected.

  Therefore, the inclination correction of the first lens L1 can be performed by adjusting the images R1 and R2 of the light source 102 so that they are concentric and the points P1 and P2 representing the respective center positions overlap.

  The lens tilt detection device of the second embodiment has the same effect as the lens tilt detection device of the first embodiment.

  Further, by arranging the plurality of LEDs 21 at the vertices of a plurality of polygons, two or more images necessary for detecting the lens tilt can be detected, and by using a plurality of LED groups as imaging targets. Even when some images of the light source cannot be detected accurately, the center position can be obtained (estimated) from the positional relationship of the other polygonal LED groups, and the detection accuracy of the lens tilt can be improved.

[Third Embodiment]
Next, a lens tilt detection apparatus according to a third embodiment of the invention will be described. In addition, the lens inclination detection apparatus of this 2nd Embodiment has the structure same as the lens inclination detection apparatus of 1st Embodiment except the lighting control of the light source 2, and uses FIG. Here, for easy understanding, the lens configuration of the optical unit 10 is a single lens configuration of the first lens L1.

  In the third embodiment, the light source 2 is a light source in which LEDs are arranged as point light sources so as to form a quadrangular shape, and individual LEDs can be controlled to be lit separately. The light emitting element used for this light source is not limited to the LED, but may be a fluorescent tube, a light bulb, a laser beam, an EL, or the like. Further, the number and arrangement of the respective LEDs may be different.

  As shown in FIGS. 9A to 9D, the lens tilt detection apparatus of the third embodiment turns on each LED individually or only at a designated location, and detects the coordinates of the image in each case. Here, the on / off of the LED of the light source 2 is controlled by the arithmetic processing unit 6 (shown in FIG. 1) including the light source control unit, but a control unit having a function of controlling the light source may be provided separately.

  In FIG. 9A, one of the four LEDs of the light source 2 is turned on, and an image R1 formed by the upper surface S1 of the first lens L1 appears at the right apex of the small square (dotted line) in FIG. 9A. An image R2 formed by the lower surface S2 of the first lens L1 appears at the left apex of the large rectangle (dotted line).

  In FIG. 9B, one of the four LEDs of the light source 2 (the LED on the opposite side of the LED lit in FIG. 9A) is turned on, and the second vertex of the small square (dotted line) in FIG. An image R1 formed on the upper surface S1 of one lens L1 appears, and an image R2 formed on the lower surface S2 of the first lens L1 appears at the right apex of the large square (dotted line) in FIG. 9B.

  In FIG. 9C, one of the four LEDs of the light source 2 (one of the other LEDs excluding the LED lit in FIGS. 9A and 9B) is lit, and the small square (dotted line) in FIG. An image R1 formed by the upper surface S1 of the first lens L1 appears at the lower vertex, and an image R2 formed by the lower surface S2 of the first lens L1 appears at the upper vertex of the large square (dotted line) in FIG. 9C.

  Further, in FIG. 9D, one of the four LEDs of the light source 2 (the LED on the opposite side of the LED lit in FIG. 9A) is lit, and the second top of the small square (dotted line) in FIG. An image R1 formed on the upper surface S1 of one lens L1 appears, and an image R2 formed on the lower surface S2 of the first lens L1 appears at the lower vertex of the large square (dotted line) in FIG. 9D.

  9A to 9D, the images R1 and R2 formed by the upper surface S1 and the lower surface S2 of the first lens L1 are rotated by 180 ° and moved in the opposite direction to the lens tilt. Except for a large case, the coordinates can be detected without the two images R1 and R2 overlapping.

  The lens tilt detection device of the third embodiment has the same effect as the lens tilt detection device of the first embodiment.

  Moreover, according to the lens inclination detection apparatus of the said 3rd Embodiment, it is possible to prevent the fall of the detection accuracy by the approach of an image or an overlap by controlling lighting of several LED which comprises the light source 2 separately. Become.

  The point light source lighting control technique of the lens tilt detection device of the third embodiment may be applied to the point light source of the lens tilt detection device of the second embodiment.

  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.

The lens tilt detection device of the present invention is
A plurality of point light sources 21 arranged on the same plane perpendicular to the reference axis m and spaced from each other, and irradiating light to the lens to be measured arranged on the reference axis m;
Reflected light from a plurality of lens surfaces of the measurement target lens L1, which is disposed on the side opposite to the measurement target lens L1 with respect to the plurality of point light sources 21 and so as to coincide with the reference axis m. An imaging camera 3 that captures a plurality of formed images of the point light source 21 generated by
The optical axis of the lens L1 to be measured with respect to the direction of the reference axis m based on the relative shift amounts of the center positions of the plurality of formed images of the plurality of point light sources 21 imaged by the imaging camera 3. And a lens inclination detecting section (4, 5, 6) for detecting the inclination angle and the inclination direction.

  According to the above configuration, the lens L1 to be measured with respect to the reference axis m direction is based on the relative shift amounts of the center positions of the plurality of formed images of the plurality of point light sources 21 imaged by the imaging camera 3. By detecting the tilt angle and tilt direction of the optical axis, the tilt of the optical axis of the lens L1 to be measured can be accurately detected even if the lens L1 to be measured is tilted with respect to the direction of the reference axis m. it can.

Moreover, in the lens tilt detection device of one embodiment,
The plurality of point light sources 21 are arranged at the vertices of a plurality of polygons.

  According to the above embodiment, by arranging the plurality of point light sources 21 at the vertices of a plurality of polygons, two or more images necessary for detecting the lens tilt can be detected, and a plurality of point light sources are to be imaged. By using a group, even if some images of the light source cannot be detected accurately, the center position can be obtained (estimated) from the positional relationship of other polygonal point light sources, and the lens tilt Detection accuracy can be improved.

Moreover, in the lens tilt detection device of one embodiment,
A light source controller 6 that controls one or more point light sources 21 of the plurality of point light sources 21 to be lit at an arbitrary timing is provided.

  According to the above-described embodiment, two light sources that are necessary for detecting the lens tilt by the light source control unit 6 that controls one or two or more point light sources 21 of the plurality of point light sources 21 so that they can be turned on at an arbitrary timing. The above images can be detected, and by appropriately selecting the lighting locations of the plurality of point light sources 21, a characteristic image can be projected onto the lens surface, and the detection accuracy of the lens tilt can be improved.

In the lens tilt detection method of the present invention,
Light from a plurality of point light sources 21 arranged at intervals on a plane perpendicular to the reference axis is irradiated to the lens L1 to be measured arranged on the reference axis m, and the lens L1 to be measured is measured. Imaging a reflected light image of the first surface of the plurality of lens surfaces with an imaging camera 3 that forms an image with an imaging system in which the optical axis coincides with the reference axis m;
Obtaining a center position of the reflected light image of the first surface imaged by the imaging camera 3 by a center position calculation unit 6a;
Forming an image of reflected light from another lens surface different from the first surface of the lens L1 by the imaging system, and capturing the image by the imaging camera;
Obtaining a center position of an image of reflected light from another lens surface different from the first surface of the lens imaged by the imaging camera 3 by the center position calculation unit 6a;
The reference axis m is based on the center position of the reflected light image on the first surface obtained by the center position calculation unit 6a and the center position of the reflected light image from another lens surface different from the first surface. And a step of calculating a tilt angle and a tilt direction of the optical axis of the lens L1 with respect to a direction by a lens tilt calculation unit 6b.

  According to the above configuration, the tilt angle of the optical axis of the lens L1 to be measured based on the relative shift amounts of the center positions of the plurality of formed images of the plurality of point light sources 21 captured by the imaging camera 3. By detecting the tilt direction, the tilt of the optical axis of the measurement target lens L1 can be accurately detected even if the measurement target lens L1 is tilted with respect to the reference axis m direction.

DESCRIPTION OF SYMBOLS 1 ... Lens inclination detection apparatus 2,102 ... Light source 3 ... Imaging camera 4 ... Signal processing part 5 ... Image processing part 6 ... Calculation processing part 6a ... Center position calculation part 6b ... Lens inclination calculation part 7 ... Display part 9 ... Imaging sensor DESCRIPTION OF SYMBOLS 10 ... Optical unit 20 ... Tilt sensor 21 ... LED
31 ... Lens unit 32 ... CCD
41 ... lens group 42 ... lens holder 43 ... actuator

Claims (4)

A plurality of point light sources arranged on the same plane perpendicular to the reference axis and spaced from each other, and irradiating light to the lens to be measured arranged on the reference axis;
It is arranged so that the optical axis coincides with the reference axis on the side opposite to the lens to be measured with respect to the plurality of point light sources, and is generated by reflected light from a plurality of lens surfaces of the lens to be measured. An imaging camera that captures a plurality of formed images of the point light source;
An inclination angle of the optical axis of the lens to be measured with respect to the reference axis direction based on the relative shift amount of the center position of each of the plurality of formed images of the plurality of point light sources captured by the imaging camera; A lens tilt detection apparatus comprising: a lens tilt detection unit that detects a tilt direction. The lens tilt detection apparatus according to claim 1,
The lens tilt detection apparatus, wherein the plurality of point light sources are arranged at vertices of a plurality of polygons. In the lens inclination detection apparatus according to claim 1 or 2,
A lens tilt detection apparatus comprising: a light source control unit configured to control one or two or more point light sources among the plurality of point light sources so as to be lit at an arbitrary timing. A plurality of lenses of the measurement target lens are irradiated with light from a plurality of point light sources arranged on a plane orthogonal to the reference axis at intervals from each other, and irradiated to the measurement target lens arranged on the reference axis. Capturing an image of the reflected light of the first surface of the surface by an imaging camera that forms an image with an imaging system in which the optical axis coincides with the reference axis;
Obtaining a center position of the reflected light image of the first surface imaged by the imaging camera by a center position calculation unit;
Forming an image of reflected light from another lens surface different from the first surface of the lens with the imaging system, and imaging with the imaging camera;
Obtaining a center position of an image of reflected light from another lens surface different from the first surface of the lens imaged by the imaging camera by the center position calculating unit;
Based on the center position of the reflected light image on the first surface and the center position of the reflected light image from another lens surface different from the first surface, which is obtained by the center position calculation unit, with respect to the reference axis direction. A lens tilt detection method comprising: calculating a tilt angle and a tilt direction of the optical axis of the lens by a lens tilt calculator.

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