JP2012058138A - Measuring object holding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify operation for attaching/detaching a lens to be inspected to/from a lens mount while utilizing a feedback control system and a mechanical stopper in order to regulate and control a rotation area of the rotary lens mount, and to prevent application of excessive load to a rotation control part of the lens mount.SOLUTION: A mount gear 30 is provided integrally with a lens mount 6 and a spindle gear 33 is engaged with a sensor gear 36. Immediately before abutting a stopper pin 39 on the edges 38a, 38b of a restriction blade 38, the lens mount 6 is stopped on a measurement start position and a measurement end position by a motor control circuit 43. A gap is formed between the stopper pin 39 and the edges 38a, 38b within a range of allowance between the teeth of the spindle gear 33 and the teeth of the mount gear 30.

Description

  The present invention is a measurement object used in an optical inspection machine that irradiates a measurement object, which is an optical component, with measurement light and images reflected light or transmitted light from the measurement object to inspect the performance and quality of the measurement object. The present invention relates to a holding device.

  In order to inspect the performance of a lens built in or used in a camera, for example, a lens inspection machine capable of measuring digitized data based on MTF (Modulation Transfer Function) is used. As such a lens inspection machine, a test chart facing a certain distance from a test lens is imaged in the air with the test lens, and the aerial image of the test chart is magnified with a magnifying optical system, and then CCD or CMOS For example, Japanese Patent Application Laid-Open No. 2004-133867 discloses a method of capturing numerical values using a type image sensor and analyzing the obtained imaging data to collect numerical data.

  The lens inspection machine described above can move both the test chart and the imaging unit within a plane perpendicular to the optical axis of the test lens, and can also measure the imaging performance of the test lens with respect to off-axis light. I am doing so. For example, when the wide-angle lens is a test lens, the measurement light is incident from an off-axis direction inclined from the optical axis of the test lens, and based on the imaging state of the test light transmitted through the test lens. It is also possible to measure the field curvature.

JP 2004-163207 A

  The conventional lens inspection machines including the lens inspection machine described in Patent Document 1 are based on the premise that the test lens is axially symmetric, and do not have a function of rotating the test lens around its optical axis during measurement. Many. However, a lens molded by plastic or glass, for example, may not always be axially symmetric depending on the surface shape of the mold and various molding conditions. In order to accurately evaluate the imaging performance of such a lens, it is necessary to accurately rotate the lens to be measured around the optical axis so that the imaging state can be measured for each rotational position. Necessary.

  To rotate the test lens held by the lens mount from the measurement start position to the measurement end position in an accurate angular step, monitor the lens mount rotation position with a rotation sensor such as a potentiometer and turn the mount rotation motor on. A feedback system for driving control may be used. In order to reproduce the rotational position of the lens mount repeatedly and accurately using such a feedback system, mechanical displacement and damage to the motor and rotation sensor link when an excessive load is inadvertently applied to the lens mount. It is necessary to make sure that no overcurrent flows to the motor for a long time. For this reason, it is effective to provide a mechanical stopper that prohibits the lens mount from rotating more than necessary, and to always utilize the feedback system in a situation where the lens mount can be rotated by an external force or motor drive.

  By the way, at the time of actual inspection / measurement work, a plurality of test lenses having the same optical specifications are prepared, and each time the test / measurement is completed according to a predetermined sequence, the test lenses are sequentially placed on the lens mount. The inspection is usually repeated while desorbing. The lens to be examined is first fixed to the lens holder, and in this state, the lens holder is attached to and detached from the mount by the bayonet method or screw method. However, if the lens mount is driven and rotated during the attachment or removal operation, the operability is poor. Therefore, it is easy to apply a mechanical stopper to the lens mount at the position where the lens holder is attached and detached so that the lens mount does not follow and rotate in the same direction when the lens holder is rotated. This is also necessary in order to prevent the lens mount driving mechanism from running out of control for some reason, and letting the lens mount rotation mechanism that requires high accuracy suffer fatal damage.

  When restricting the rotation of the lens mount at the position where the lens holder is attached / removed as described above, for example, the configuration in which the stopper of the electromagnetic drive system is engaged / disengaged with the lens mount increases the number of parts including the actuator and its control circuit, thereby increasing the cost. become. In addition, when the lens mount is abutted against a stationary stopper, the rotation is stopped when the lens holder is attached, and the mount is rotated counterclockwise when the lens holder is removed. It is necessary to set a stop position of the lens mount that is prevented from rotating by contact with these stoppers beyond the rotation range at the time of measurement. Therefore, under the state where the feedback system is utilized, the lens mount cannot be rotated to the attachment / detachment position of the lens holder only by the rotation control sequence for inspection / measurement.

  In addition, it is the simplest configuration if the measurement start position and the lens holder mounting position, and the measurement end position and the lens holder removal position can be matched exactly, but the rotation control is electrically controlled by a feedback system. It is extremely difficult to make the rotation stop position of the motor to be exactly the same as the stop position of the mount that is mechanically positioned by contact with the mechanical stopper. For example, in order to position the lens mount at the measurement start position, measurement is performed when the rotation of the lens mount is prevented by contact with the stopper even though the motor is driven by receiving a signal from the feedback system. Until the measurement at the start position is completed, the overcurrent remains supplied to the motor, and the motor may generate heat and be damaged.

  The present invention has been made in consideration of the above circumstances. In an optical inspection machine such as the lens inspection machine described above, measurement is performed by irradiating a measurement object with the measurement light and imaging the inspection light obtained by reflection or transmission. When inspecting the reflection and transmission characteristics of an object, it is possible to measure under various conditions by holding the object to be rotated, and to load the rotation mechanism for rotating the object to be measured. It is an object of the present invention to provide a measurement object holding device that allows a measurement object to be easily attached to and detached from the holding member without giving.

  In order to achieve the above object, the measurement object holding device of the present invention is configured such that the measurement object is attached by a mounting operation involving rotation in one direction of the measurement object and is removed by a removal operation involving rotation in the other direction. The object is removed, and is rotatably supported by the base and meshes with a rotation holding member that rotates the attached measurement object integrally around a certain axis, and a ring gear fixed to the rotation holding member. A rotation sensor having a spindle gear and rotating the rotation holding member, a sensor gear meshing with the ring gear and outputting a detection signal corresponding to the rotation of the rotation holding member, and the rotation holding member starting measurement A drive signal corresponding to a target rotation position of the rotation holding member is supplied to the motor when the rotation angle is within a predetermined measurement angle range from the position to the measurement end position; The first position exceeding the measurement start position and the measurement end position are determined by engaging the motor holding circuit and the rotation holding member while monitoring the detection signal obtained from the rotation sensor. A stopper for mechanically limiting the rotation range of the rotation holding member between the second position and the second position, and between the measurement start position and the first position and between the measurement end position and the second position. The amount of rotation of the rotation holding member is within the range of engagement play between the ring gear and the spindle gear.

  The present invention can be suitably used for a lens mount of a lens inspection machine that evaluates and measures the imaging performance of a lens. In this case, the test lens that is the measurement object is attached to the lens mount that is the rotation holding member, and the lens mount is configured so that the test lens can rotate about the center of its optical axis. When sequentially inspecting mass-produced lenses as test lenses, instead of attaching the test lens directly to the lens mount, attach the test lens to the dedicated lens holder and then attach the lens holder. It is easy to attach to the lens mount by screwing. In order to be able to evaluate the axial symmetry of the test lens, the measurement light can be made incident at a rotationally symmetric position of 180 ° with respect to the optical axis of the test lens, and the lens mount is centered on the optical axis. It is desirable to be able to rotate up to 180 °, and in order to reduce the impact when the lens mount and the stopper come into contact with each other, the motor control circuit is informed according to the difference between the current position and the target rotational position. It is effective to provide a function of driving the motor so that the rotational force is different.

  According to the present invention, an excessive burden is imposed on the rotation mechanism that performs high-precision rotation control of the rotation holding member that holds the measurement object during measurement without complicating the mechanical or electrical configuration of the optical inspection machine. In addition, it is possible to easily remove the measured measurement object from the rotation holding member and attach a new measurement object.

It is a schematic plan view of the lens inspection machine using this invention. It is principal part sectional drawing of the lens inspection machine shown in FIG. It is a principal part top view of a lens mount. It is a principal part front view of a lens mount. It is a functional block diagram which shows the outline | summary of the rotation control part of a lens mount. It is a flowchart which shows the measurement sequence of a lens inspection machine. It is operation | movement explanatory drawing by the rotation control part of a lens mount.

  The present invention can be suitably used for a lens inspection machine that measures the imaging performance of a lens using MTF or the like. In this case, for example, the measurement light from the collimator is incident on the test lens, and the imaging performance of the test lens is measured by imaging the imaging state of the test light transmitted through the test lens. In FIG. 1 and FIG. 2 showing an example of a lens inspection machine using the present invention, a surface plate 2 is used as a base having a horizontal upper surface, and a mount base 3 is fixed to the upper surface of the surface plate 2. A bracket 4 fixed to the base 3 holds a cylindrical mount holder 5. A cylindrical lens mount 6 is rotatably incorporated in the mount holder 5 via a bearing incorporated in its inner wall. A lens holder 8 holding a test lens 7 is attached to the front end portion of the lens mount 6. The lens mount 6 functions as a rotation holding member that rotatably holds the test lens 7 to be measured around the optical axis P. The test lens 7 rotates around the optical axis P as the lens mount 6 rotates. Rotate together.

  In order to fix the lens holder 8 to the lens mount 6, screws are cut on the inner peripheral wall of the front end portion of the lens mount 6 and the outer peripheral wall of the rear end of the lens holder 8, and these are screwed together to fix the lens holder 8. Done. Since these screws are composed of ordinary right-hand screws, the lens holder 8 can be easily attached by turning it clockwise, and can be removed by turning it counterclockwise. The lens holder 8 is formed with a lens holding portion precisely processed according to the shape and size of the test lens 7 so that the test lens 7 can always be fixed to the lens holder 8 in a fixed state. . In addition, the lens mount 6 and the lens holder 8 can be attached / detached using a bayonet method with a rotation operation. For example, the lens mount 6 and the lens holder 8 are attached by rotating in a clockwise direction at a predetermined angle after being pushed in the axial direction. It is also possible to adopt a mode in which the shaft is extracted in the axial direction after rotating counterclockwise.

  An on-axis collimator 10 is provided on the optical axis P, and off-axis collimators are provided on both sides of the optical axis P so that measurement light can be incident on the lens 7 held by the lens mount 6 from various directions. 11 and 12 are provided. The on-axis collimator 10 causes measurement light to enter the lens 7 to be tested along the optical axis P, and the off-axis collimators 11 and 12 allow measurement light to enter from both sides of the optical axis P from the off-axis.

One of the off-axis collimators 11 and 12 can be omitted if the test lens 7 can be rotated in the range of 360 ° together with the lens mount 6. However, in this lens inspection machine, the test lens 7 Each time the rotation position of the lens 7 is changed, the measurement light is incident from both off-axis collimators 11 and 12 and the measurement is sequentially performed. Therefore, the rotation range of the lens 7 to be measured is basically 180 °. It has become.

  Each of the off-axis collimators 11 and 12 is supported on swing stages 15 and 16 that are movable along rectilinear guides 13 and 14 that are inclined symmetrically about ± 30 ° with respect to the optical axis P. Each of the swing stages 15 and 16 supports the off-axis collimators 11 and 12 so as to be swingable in a horizontal plane parallel to the upper surface of the surface plate 2. Therefore, as shown in the figure, the measurement light can be incident on the lens 7 to be examined from any direction by using the off-axis collimators 11 and 12.

Since the rectilinear guides 13 and 14 are inclined so as to move away from the optical axis P as they are closer to the lens mount 6, even if the off-axis collimators 11 and 12 are brought closer to each other, the front ends thereof are not brought into contact with the test lens 7. Measurement light can be incident on the lens 7 at a large angle. Thereby, even if the test lens 7 is of a super wide angle or fisheye type, it is possible to perform a wide range of measurement in consideration of the maximum angle of view.

  The on-axis collimator 10 faces the lens 7 to be examined and allows measurement light to enter from the optical axis P parallel to the upper surface of the surface plate 2. As exemplified by the on-axis collimator 10, each collimator 10, 11, 12 includes a white LED 18 serving as an illumination light source, an illumination optical system 19 including a diffusion plate and a condenser lens, and a chart plate provided in a turret manner. 20 is illuminated. The chart plate 20 is provided with a different chart design depending on its rotational position. For example, an appropriate one selected according to the magnification of the lens 7 to be examined and the measurement conditions is set in the optical path of the illumination optical system 19. Is done. Since the chart plate 20 is located on the focal plane of the collimating lens 21, the measurement light from the chart pattern is emitted from the collimating lens 21 as a parallel light beam in any collimator 10, 11, 12.

  The movement and swing of the off-axis collimators 11 and 12 are basically automatically executed by a dedicated actuator in accordance with the initial setting of measurement conditions. That is, when the imaging performance of the lens 7 to be measured is measured, the measurement conditions are initially set, and a measurement sequence is automatically created under the measurement conditions thus initialized. The operation of each collimator 10, 11, 12 is automatically controlled based on the sequence. Further, after the measurement is started, the test lens 7 is rotated around the optical axis together with the lens mount 6 as necessary, and the rotation angle, the timing of the rotation, and the like are automatically performed according to the measurement sequence.

  A three-dimensional stage 22 is provided behind the mount base 3, and a camera unit 24 is supported by a bracket 23 fixed to the three-dimensional stage 22. The three-dimensional stage 22 receives a driving force from the drive unit 22a, and is in the horizontal X-axis direction in the plane perpendicular to the optical axis P, in the Y-axis direction perpendicular to the X-axis in the same plane, and in the optical axis P. The camera unit 24 is moved in three parallel Z-axis directions.

  The camera unit 24 has a microscope 26 with a built-in magnifying optical system, a lens barrel unit 27 containing an imaging optical system that forms an image of a light beam emitted from the microscope 26, and an image obtained by the imaging optical system. The microscope 26 and a part of the lens barrel part 27 enter the hollow part of the lens mount 6. The microscope 26 enlarges a chart pattern image (hereinafter referred to as a chart image) imaged in the air by the test lens 7 and transmits the image to the imaging optical system of the lens barrel portion 27, and the image sensor in the camera portion 28. An enlarged chart image is formed. Since both the on-axis collimator 10 and the off-axis collimators 11 and 12 receive a parallel light beam from the chart design, the image plane of the chart image coincides with the focal plane of the lens 7 to be examined.

  By performing image processing on the imaging signal obtained by imaging the chart image, numerical data based on the MTF can be obtained, and the imaging performance of the test lens 7 can be objectively evaluated. The test lens 7 is not limited to a single lens as shown in the figure, and may be a combination of a plurality of lenses.

When measuring the MTF of the test lens 7, the camera unit 24 is first moved in a plane perpendicular to the optical axis P to adjust the position of the microscope 26 according to the position of the chart image formed in the air by the test lens 7. To do. Thereafter, a chart image is taken while the camera unit 24 is moved finely in the direction of the optical axis P, and the MTF value at the best focus position is calculated. By calculating the MTF value while moving the camera unit 24 in the direction of the optical axis P, the best focus position and its MTF value are interpolated without necessarily measuring the camera unit 24 by moving it to the best focus position. Can be obtained.

  In the measurement using the on-axis collimator 10, the camera unit 24 is moved in the X and Y axis directions in a plane perpendicular to the optical axis P, so that the digitized data at a position off the optical axis P is obtained. Can also be imported. On the other hand, when the measurement light is incident from the direction greatly inclined from the optical axis P using the off-axis collimators 11 and 12, the measurement light is incident on the horizontal plane passing through the center of the lens 7 to be measured. Therefore, in order to evaluate the axial symmetry of the test lens 7 as well, it is necessary to perform measurement while rotating the test lens 7 together with the lens mount 6.

  As shown in FIG. 3, a mount gear 30 is fixed to the rear end of the lens mount 6 and protrudes from the rear end edge of the mount holder 5. A motor 32 is fixed to the bracket 4 that holds and holds the mount holder 5, and a spindle gear 33 fixed to the shaft is meshed with the mount gear 30. Then, the lens mount 6 rotates in the hollow portion of the mount holder 5 by driving the motor 32. A potentiometer 35 is fixed to the bracket 4, and the sensor gear 36 fixed to the shaft of the potentiometer 35 is engaged with the mount gear 30. The potentiometer 35 functions as a rotation sensor that detects the rotation angle of the lens mount 6.

  On the outer periphery of the lens mount 6, an arc-shaped limiting plate 38 extending in an arc shape along substantially half of the circumference is integrally formed. Correspondingly, a stopper pin 39 is implanted on the front end surface of the mount holder 5. It is installed. When one end edge 38a of the limiting plate abuts against the stopper pin 39 as shown in the process in which the lens mount 6 rotates counterclockwise, the lens mount 6 is prevented from rotating counterclockwise. Similarly, when the other edge 38b of the limiting plate comes into contact with the stopper pin 39 in the process of rotating the lens mount 6 in the clockwise direction, the lens mount 6 is prevented from rotating in the clockwise direction at that time. The mechanical stopper which restrict | limits the rotation range of 6 is comprised.

  As shown in FIG. 5, the motor 32 is rotated by a drive signal from the motor driver 42. A drive signal from the motor driver 42 is controlled by a motor control circuit 43 so that the rotational speed of the motor 32 can be adjusted by, for example, a PWM (pulse width control) method. The potentiometer 35 inputs a detection signal corresponding to the rotation amount of the lens mount 6 to the motor control circuit 43 via the sensor gear 36. The motor control circuit 43 controls the drive signal supplied from the motor driver 42 to the motor 32 while monitoring the detection signal from the potentiometer 35. As a result, the motor 32 for driving the lens mount 6 is controlled by a feedback method, and the rotation speed is increased as the required rotation angle increases, and the rotation speed decreases as the required rotation angle decreases. To be controlled.

  The operation of this lens inspection machine is entirely controlled by the system controller 45, and depends on various measurement conditions input from the measurement condition setting unit 46 prior to the start of measurement, optical specification data of the lens 7 to be measured, and the like. The measurement sequence is automatically executed. For example, whether or not the off-axis collimators 11 and 12 are used, the rotation step angle when the measurement is performed while rotating the test lens 7, and the incidence when the measurement light is incident from the off-axis of the test lens 7. If a variable range of the angle is input, the collimators 10, 11, and 12 of the lens inspection machine are automatically operated under the measurement sequence suitable for these conditions to perform measurement.

  This lens inspection machine includes off-axis collimators 11 and 12 in addition to the on-axis collimator 10 at symmetrical positions with respect to the optical axis P, and rotates the lens mount 6 within a range of 180 ° to rotate 360 ° around the optical axis. It enables measurement light to enter from an angle range. The outer diameters of the end edges 38a and 38b of the limiting plate 38 and the stopper pin 39 are determined so that the lens mount 6 can be rotated within a measurement angle range of 180 °.

However, a characteristic point here is that a measurement sequence is executed by the system controller 45, and a rotation command signal is input from the system controller 45 to the motor control circuit 43. In response to this, the motor control circuit 43 and the motor driver 42 When the motor 32 is driven normally, the end edges 38a and 38b of the limiting plate 38 do not come into contact with the stopper pin 39 regardless of whether the lens mount 6 is rotated to the measurement start position or the measurement end position. Yes. When the lens mount 6 is stopped by stopping the driving of the motor 32, the gap left between the stopper pin 39 and the end edges 38a and 38b is the mount gear 30 and the spindle at each of the measurement start position and the measurement end position. It is set within the range of the engagement play between the teeth generated at the engagement portion with the gear 32.

  Hereinafter, the operation of the above configuration will be described with reference to the flowchart of FIG. When the power-on operation is performed, the motor control circuit 43 is activated in response to the initial setting command from the system controller 45, and the rotation control feedback system of the lens mount 6 is turned on. Subsequently, the motor control circuit 43 controls the drive of the motor 32 so as to stop the lens mount 6 at the measurement start position (0 ° position) while monitoring the detection signal from the potentiometer 35.

Basically, the lens mount 6 should have stopped at the measurement start position when the previous measurement operation is completed. However, if the lens mount 6 has deviated from the measurement start position by some external force, the lens mount 6 Is automatically rotated clockwise. Then, as shown in FIG. 7A, the end edge 38b of the limiting plate 38 integrated with the lens mount 6 approaches the lower side of the stopper pin 39, and stops with a gap D1 remaining therebetween. In addition, the enlarged view of the part enclosed by area | region X and Y is typically shown in each double circle.

  The lens mount 6 is rotated clockwise by the rotation of the motor 32 driven under the control of the motor control circuit 43, and is stopped at the measurement start position. Then, since the counterclockwise rotation of the spindle gear 33 rotates the mount gear 30 in the clockwise direction, play (backlash) D2 is generated on the rear side in the rotation direction of the teeth of the spindle gear 33 on the drive side. ing. With respect to this play D2, the above-described gap D1 is determined so as to satisfy a relationship of D2 ≧ D1.

  As described above, after the lens mount 6 automatically stops at the measurement start position, measurement conditions are set according to the performance and optical specifications of the lens 7 to be measured. For example, when the test lens 7 is a fish-eye lens, the measurement light is incident at a maximum incident angle from the off-axis collimators 11 and 12, and the measurement is performed while rotating the test lens 7 around the optical axis. Set conditions such as how much the rotation pitch angle is to be performed. In addition, by inputting the optical data of the lens 7 to be examined, the position of the entrance pupil when the measurement light is incident from outside the optical axis P is automatically calculated. After the measurement sequence is executed, the straight guide The off-axis collimators 11 and 12 are automatically positioned by the positions 13 and 14 and the swing stages 15 and 16 at positions where the measurement light is incident toward the entrance pupil position.

  A lens holder 8 holding the test lens 7 is attached to the lens mount 6 stopped at the measurement start position. The lens holder 8 is screwed onto the inner peripheral wall of the front end of the lens mount 6 with a right screw. However, as described above, the end edge 38b of the limiting plate 38 stops at a position close to the lower side of the stopper pin 39. When the lens holder 8 is rotated clockwise, the lens mount 6 is also rotated in the clockwise direction following the mounting operation. When the mount gear 30 is rotated clockwise, the play D2 is left on the front side of the teeth of the mount gear 30 as shown in FIG. 7A. Therefore, the lens mount 6 is almost unloaded by the play D2. To rotate clockwise.

  The clockwise rotation of the lens mount 6 is prevented when the end edge 38b of the limiting plate 38 contacts the lower edge of the stopper pin 39 as shown in FIG. Therefore, the spindle motor 33 and the motor 32 do not rotate counterclockwise because the clearance D1 is equal to or less than the play D2 between the teeth of the spindle gear 33 and the teeth of the spindle gear 33. However, since the engagement between the mount gear 30 and the sensor gear 36 is such that there is little play, the sensor gear 36 rotates counterclockwise as the mount gear 30 rotates, and the potentiometer A detection signal is input from 35 to the motor control circuit 43.

  Upon receiving this detection signal, the motor control circuit 43 tries to drive the motor 32 to return the spindle gear 33 in the clockwise direction in order to return the lens mount 6 in the counterclockwise direction, but the detection signal itself is very slight. Since it corresponds to the amount of rotation, the level of the drive signal supplied to the motor 32 is also very small. Further, as shown in FIG. 7B, since the rotation of the spindle gear 33 in the clockwise direction is mechanically blocked by the mount gear 30 without play, the motor 32 is moved from the position corresponding to the initial measurement start position. It does not rotate. As a result, the drive signal is supplied to the motor 32 with the rotation of the spindle gear 33 mechanically locked, but the level of the drive signal is sufficiently small so that the motor 32 is not damaged.

  When the mounting operation of the test lens 7 is completed and the clockwise rotational force applied to the lens mount 6 is released, the motor 32 is rotated by the drive signal from the motor control circuit 43, and the spindle gear 33 is slightly changed. Rotate clockwise. In conjunction with this, the lens mount 6 rotates counterclockwise, and the sensor gear 36 also rotates with this. Then, as shown in FIG. 7C, when the gap D1 is formed between the lower edge of the stopper pin 39, the detection signal from the potentiometer 35 is also zero, and the motor 32 is stopped. As a result, as shown in FIG. 7C, the lens mount 6 returns to the original measurement start position and enters a state of waiting for execution of the measurement sequence.

The play D2 between the teeth of the mount gear 30 and the teeth of the spindle gear 33 occurs on the opposite side to that in the case of FIG. 7A, but at the start of the measurement sequence, the play of the spindle gear 33 is caused by the play D2. Rotate towards the non-occurring side. Since the spindle gear 33 only rotates in the same direction toward the measurement end position until a series of measurement sequences is completed, the rotation control of the lens mount 6 is accurately performed without being affected by the play D2. Will come to be.

  After the test lens 7 is attached as described above, when a measurement start operation is performed and a measurement sequence is executed, basically, the measurement light from the on-axis collimator 10 is first applied to the test lens 7. Incident along axis P. Since the optical specification data of the lens 7 to be examined has already been input, the focal plane in the optical design is known in advance, and the measurement light is parallel light from the chart design on the chart plate 20, so that the standard Specifically, the chart design is formed as an aerial image on the focal plane of the lens 7 to be examined. The camera unit 24 is positioned in advance by adjusting the three-dimensional stage 22 so that the front focal point of the microscope 26 comes to the focal plane of the lens 7 to be examined on the optical axis P. Measurement data is collected by sequentially capturing images while sending the camera unit 24 in the Z-axis direction at regular intervals.

  Measurement using the on-axis collimator 10 is sufficient for measurement on the optical axis P or in the paraxial range, but off-axis collimators 11 and 12 are used for performance inspection with respect to off-axis light. Parallel light from the chart design on the chart plate 20 is used as measurement light in exactly the same way from the off-axis collimators 11 and 12. Therefore, basically, the focal plane of the lens 7 to be tested becomes the planned imaging plane, but the measurement light from the off-axis is imaged at a position off the optical axis P according to the incident angle. When performing a performance test on the off-axis light of the lens 7 to be tested, the measurement conditions are input in advance, and the setting of the incident angle of the measurement light on the lens 7 to be tested and the optical axis symmetry test are performed. Whether or not, and when the optical axis symmetry is inspected, a step angle is set when the lens 7 to be tested is rotated around the optical axis.

  For example, when the incident angle of the measurement light is set to 45 ° and the optical performance is measured over the entire circumference while rotating the test lens 7 by 10 ° around the optical axis, the measurement by the on-axis collimator 10 is completed. Thereafter, the two off-axis collimators 11 and 12 move symmetrically on the linear guides 13 and 14, and the swing stages 15 and 16 operate to move the off-axis collimators 11 and 12 at a predetermined position and at a predetermined position. Automatically adjust to posture. Note that in an ultra wide-angle lens such as a fish-eye lens, the incident pupil position may move on the optical axis P as the incident angle increases. Since these conditions can be grasped in advance based on the original data, each of the off-axis collimators 11 and 12 is automatically set at an optimum position where the measurement light can be incident on the lens 7 to be examined at an incident angle of 45 °. It is possible to move to.

  In the measurement using the measurement light from the off-axis, first, the measurement light is incident from the off-axis collimators 11 and 12 with the lens mount 6 at the measurement start position (0 ° position). From the off-axis collimators 11 and 12, the measurement light is incident on the lens 7 to be examined at an incident angle of ± 45 ° in the horizontal direction with respect to the optical axis P. The positions at which the respective chart symbols are imaged are known in advance. . Therefore, as in the measurement process using the on-axis collimator 10, the chart unit images are sequentially taken by the off-axis collimators 11 and 12 while moving the camera unit 24 in the X, Y, and Z axis directions. Collect measurement data. When the measurement using the off-axis collimators 11 and 12 is completed at the measurement start position (0 ° position), the lens mount 6 automatically rotates counterclockwise by 10 ° from the measurement start position shown in FIG. To do.

  Thereafter, the measurement is performed at the 10 ° rotation position in the same procedure, and further measurement is performed at the 20 ° rotation position, the 30 ° rotation position,..., And the measurement at the 180 ° rotation position is completed. Measurement of the lens 7 is completed. However, in the normal measurement, it is necessary to sequentially inspect a plurality of test lenses 7 manufactured in the same lot, and the measured sample is removed from the lens mount 6 and the next sample is attached to the lens mount 6. Operation is required. When the measurement of the first sample is completed, the lens mount 6 is stopped at the measurement end position (180 ° rotation position) shown in FIG.

  Since the lens mount 6 is stopped by driving the motor 32 under the control of the motor control circuit 43, the measurement end position is not shown between the end edge 38a of the limiting plate 38 and the upper edge of the stopper pin 39. The gap D1 described in 7 (A) remains. Then, the lens holder 8 is rotated counterclockwise in order to remove the lens 7 to be examined. Then, the lens mount 6 is also driven to rotate counterclockwise within a range not exceeding the play D2 between the teeth of the spindle gear 33 and the teeth of the mount gear 30, and the rotation of the lens mount 6 is caused by the stopper pin 39 and the edge 38 a of the limiting plate 38. Is blocked at the point of contact.

  However, due to the rotation, a detection signal is output from the potentiometer 35 via the sensor gear 36, whereby the motor control circuit 43 sends a drive signal to the motor 32 to rotate the mount gear 30 clockwise via the spindle gear 33. Try to. However, while the removal operation of the lens 7 is being performed, the removal operation of the lens holder 8 is resumed even if the undo gear 30 is rotated clockwise even when the hand is released during the removal operation. Each time it is forced to rotate counterclockwise. In the process of such an operation, as in the case of the mounting operation of the lens 7 to be examined, the drive signal is supplied to the motor 32 with the rotation of the spindle gear 33 being mechanically locked. The motor 32 is sufficiently small and will not be damaged.

  When the removal operation of the test lens 7 is completed and the counterclockwise rotational force applied to the lens mount 6 is released, the motor 32 is rotated by the drive signal from the motor control circuit 43 and the spindle gear 33 is moved. Slightly turns counterclockwise. In conjunction with this, the lens mount 6 rotates in the clockwise direction, and the sensor gear 36 also rotates with it. When the gap D1 is generated between the end edge 38a of the limiting plate 38 and the upper edge of the stopper pin 39, the detection signal from the potentiometer 35 is also zero and the motor 32 is stopped. As a result, the lens mount 6 returns to the original measurement end position (180 ° rotation position) and waits for the measurement sequence to resume.

  In this way, the lens 7 to be tested is detached from the lens mount 6 together with the lens holder 8 to complete the measurement of the first sample. If there is no sample to be measured next, the measurement completion operation is performed. Upon receiving this measurement completion operation, the motor control circuit 43 is activated, and the lens mount 6 is automatically returned to the measurement start position shown in FIG. When the next sample is prepared, an initial position return operation is performed. When the initial position return operation is performed, the lens mount 6 is automatically returned to the measurement start position under the control of the motor control circuit 43. Then, the next sample is attached as the test lens 7 to the lens mount 6 that has returned to the measurement start position, and the operation thereof is as described with reference to FIG.

  As described above, the present invention has been described according to the illustrated embodiment. However, the present invention does not necessarily have a function of allowing measurement light to be incident on the test lens from both on-axis and off-axis. As long as it has a lens mount that holds the lens rotatably, it can be equally applied. In addition, it is possible to adopt various modes as the measurement sequence. For example, the attachment / detachment of the lens to be examined is electrically identified, and the lens mount is automatically returned to the measurement start position using the identification signal. It is also possible to create a sequence.

  Furthermore, in the illustrated example, parallel light is used as measurement light incident on the test lens. For example, the test lens is attached to a lens mount provided at a certain distance from the test chart, and The present invention can also be used for an inspection machine in which object light is directly imaged on a screen or formed as an aerial image, and the image is taken to collect measurement data. In addition, a mechanical stopper is configured by contacting either end of the limit plate 38 integrated with the lens mount 6 in an arc shape with a single stopper pin. A piece-like protrusion may be provided so that both ends of the rotation area are regulated by individually provided stoppers.

  In the embodiment of the present invention described above, the optical component that is the measurement object is the lens to be measured, and the rotatable lens mount that holds the measurement object corresponds to the rotation holding member that rotatably holds the measurement object. However, the present invention can be applied not only to such a lens inspection machine but also to a measuring machine for optical components such as a mirror and a prism. Even with these measuring instruments, when the measurement light from the light source is incident on the measurement object, it is measured how the position and amount of reflected or transmitted light change depending on the rotational position of the measurement object. By doing so, it becomes possible to evaluate the optical performance of a mirror, a prism or the like.

4 Bracket 5 Mount holder 6 Lens mount 7 Test lens 8 Lens holder 10 On-axis collimator 11, 12 Off-axis collimator 20 Chart plate 22 Collimator lens 24 Camera unit 30 Mount gear 32 Motor 33 Spindle gear 35 Potentiometer 36 Sensor gear 38 Limit plate 39 Stopper pin 43 Motor control circuit

Claims (6)

Provided in an optical measuring machine that measures the optical performance of the measurement object by making the measurement light incident on the measurement object, imaging the inspection light reflected or transmitted from the measurement object, and in the irradiation light path of the measurement light In the measurement object holding device that holds the measurement object,
The measurement object is attached by a mounting operation with rotation in one direction of the measurement object, and the measurement object is removed by a removal operation with rotation in another direction, and is rotatably supported and attached to the base. A rotation holding member that rotates the measured object integrally around a certain axis;
A motor having a spindle gear meshing with a ring gear fixed to the rotation holding member, and rotating the rotation holding member around the fixed axis;
A rotation sensor that has a sensor gear meshing with the ring gear and detects a detection signal according to the rotation of the rotation holding member;
When the ring gear is located within the measurement angle range from the measurement start position to the measurement end position, a drive signal corresponding to the target rotation position of the rotation holding member is supplied to the motor, and detection obtained from the rotation sensor A motor control circuit for controlling the driving of the motor while monitoring signals;
Due to the engagement with the rotation holding member, the rotation region of the rotation holding member is mechanically moved between a first position exceeding the measurement start position and a second position exceeding the measurement end position from the measurement angle range. And a stopper that restricts to
The amount of rotation of the rotation holding member between the measurement start position and the first position and between the measurement end position and the second position is within a range of engagement play between the ring gear and the spindle gear. A measuring object holding device.   2. The rotation holding member is a lens mount to which a test lens to be measured is attached, and holds the attached test lens so as to be rotatable around its optical axis. Measuring object holding device.   The test lens held by the lens mount receives a parallel light beam as a measurement light from a collimator in which a test chart is incorporated, and measures the test chart image formed by the test lens. The measurement object holding device according to claim 2, wherein the measurement object holding device is used in a lens inspection machine that performs the above. The measurement object holding device according to claim 3, wherein the lens mount has a mounting screw to which a lens holder holding the lens to be tested is integrally connected by screwing.   The measurement object holding device according to claim 4, wherein a rotation angle from a measurement start position to a measurement end position of the lens mount is 180 °. The measurement object holding device according to claim 1, wherein the motor control circuit drives the motor with a drive signal having a different rotational force according to a difference between a current position and a target rotation position. .

Images