Method and device for detecting eccentricity of lens

Abstract

The present invention relates to a method and device for detecting the eccentricity of a lens, the device comprising an eccentricity detector (1) and a turntable (2), a support device (4) and a distance meter (5) movably arranged on the support device (4), wherein the light of the distance meter (5) is irradiated onto the outer circle of the lens to be detected. The present invention uses the distance meter to measure the horizontal offset of the lens to be detected, so that the horizontal offset can be deducted when calculating the actual eccentricity, thereby eliminating the need to set a centering device, thereby reducing the wear on the lens and improving the detection efficiency.

Description

Technical Field

[0001] The present invention relates to the field of optical device detection, and in particular to an eccentricity detection method and an eccentricity detection device for detecting the eccentricity of a lens. Background Art

[0002] As an important part of the lens, the lens plays a key role in the imaging quality of the entire lens. In the prior art, the eccentricity detection method is to fix the lens on a rotating platform, fix the lens on the rotating platform by a tooling, set an eccentricity detector above the rotating platform, and rotate the rotating platform to perform eccentricity detection. This method requires the lens to be coaxial with the rotating platform during detection, and the lens of different sizes needs to be adjusted again when replaced, and the detection efficiency is low. Summary of the invention

[0003] The object of the present invention is to provide a method and device for detecting eccentricity without the need for lens centering.

[0004] To achieve the above object, the present invention provides a method for detecting the eccentricity of a lens, comprising the following steps:

[0005] a. Make the light of the eccentricity detection device shine on the tested mirror surface of the lens to be tested, and make the light of the distance measuring device shine on the outer circle of the lens to be tested;

[0006] b. Rotate the lens to be tested, and calculate the eccentricity measurement value of the tested mirror surface and the horizontal offset of the lens to be tested based on the light reflected from the tested mirror surface and the outer circle of the lens;

[0007] c. Calculate the actual eccentricity of the measured mirror using the eccentricity measurement value and the horizontal offset.

[0008] According to one aspect of the present invention, in step (a), the light irradiated on the measured mirror surface is convergent light, and the extended line of the convergent light irradiates the center of the lens.

[0009] According to one aspect of the present invention, in step (b), the image formed by the light reflected from the measured mirror surface can rotate as the lens rotates, and the calculation formula of the measured value of the eccentricity is:

[0010] Eccentricity measurement value = radius / magnification;

[0011] Among them, the radius refers to the radius of the rotation trajectory circle of the image formed by the light reflected from the measured mirror surface, and the magnification refers to the magnification of the optical system used to converge the light irradiated onto the measured mirror surface.

[0012] According to one aspect of the present invention, in step (b), the calculation formula of the horizontal offset is:

[0013] Horizontal offset = (maximum value of horizontal distance measurement - minimum value of horizontal distance measurement) / 2

[0014] The maximum value of the horizontal distance measurement and the minimum value of the horizontal distance measurement refer to the distance measurement values ​​when the device for receiving the light reflected from the outer circle of the lens is farthest and closest to the outer circle of the lens, respectively.

[0015] According to one aspect of the present invention, the calculation formula of the actual eccentricity in step (c) is:

[0016] Actual eccentricity = measured eccentricity - horizontal offset.

[0017] The eccentricity detection device for lenses comprises an eccentricity detector and a turntable, a supporting device and a distance meter movably arranged on the supporting device, and the light of the distance meter is irradiated onto the outer circle of the lens to be tested.

[0018] According to one aspect of the present invention, the supporting device is a three-axis adjustment platform or a three-dimensional adjustment platform, and the rangefinder can be adjusted by it to emit light that can illuminate the outer circle of the lens to be tested.

[0019] According to one aspect of the present invention, the eccentricity detector comprises a detector body and a column;

[0020] The detector body includes a detection end, a connection end, and a dual-axis adjustment platform for driving the detection end to move;

[0021] The connecting end is connected to the column via a guide rail.

[0022] According to one aspect of the present invention, the turntable is provided with an air passage and an air pump connected to the air passage.

[0023] According to one aspect of the present invention, it also includes a base for supporting the column, the turntable and the supporting device;

[0024] The turntable is an air-floating turntable.

[0025] According to one solution of the present invention, a rangefinder is added to detect the horizontal offset of the lens. In the subsequent calculation process, the horizontal offset can be deducted from the eccentricity measurement value measured by the eccentricity detector to obtain the actual eccentricity of the side mirror. In this way, there is no need to set a centering device on the air-floating turntable, and there is no need to perform centering during the detection process. This will not cause wear to the outer circle of the lens, and the centering step is omitted, thereby improving the detection efficiency.

[0026] According to one solution of the present invention, an air pump is added to form negative pressure in the air passage of the air floating turntable, thereby adsorbing the lens on the turntable, so that the lens is not easily moved relative to each other and thus worn when the turntable of the turntable rotates. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a structural diagram schematically showing an eccentricity detection device according to an embodiment of the present invention;

[0028] Figure 2 FIG. 1 is a detection flow chart schematically showing an eccentricity detection device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or positional relationship shown in the relevant drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0031] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not therefore limited to the following embodiments.

[0032] Figure 1 Schematically shows the structure of an eccentricity detection device according to an embodiment of the present invention. Figure 1 As shown in FIG. 1 , the eccentricity detection device of the present invention comprises an eccentricity detector 1, a turntable 2, a support device 4, a distance meter 5 and a base 6. Of course, the base 6 is not a necessary component, and its function is to support other devices. The eccentricity detector 1 is divided into a detector body 1a and a column 1b, and the column 1b is fixed to the base 6 by a set screw. The detector body 1a is divided into a detection end and a connection end (i.e. Figure 1The left and right ends of the detector are connected to the column 1b, wherein the connecting end is connected to the column 1b, and the detecting end is equipped with a light source, a cross target, an optical system and an image sensor (i.e., a camera). The light emitted by the light source can be transformed into a cross light after passing through the cross target, and then converged through the optical system. Since the light needs to be converged at the center of curvature of the upper mirror surface of each lens (i.e., the center of the lens sphere) when detecting the eccentricity of the lens, and the present invention can detect the upper and lower mirror surfaces of the lens separately when detecting the lens, the convergence point corresponds to the center of curvature of the surface to be detected when detecting different surfaces. Therefore, the detector body 1a needs to be able to move on the column 1b, so the present invention sets a guide rail on the column 1b, and the connecting end of the detector body 1a is connected to the guide rail. As a result, the detector body 1a can make a straight line movement up and down on the column 1b, and is tightened by a knob after moving into place. However, since the eccentricity detection device of the present invention is not provided with a centering device, the lens may be offset in the horizontal direction when placed on the turntable 2. Therefore, the light emitted by the detection end of the detector body 1a cannot accurately locate the above-mentioned curvature center only by moving up and down. Therefore, a dual-axis adjustment platform should be provided to drive the detection end to move forward, backward, left and right in the horizontal direction.

[0033] The turntable 2 is also supported on the base 6, which is arranged below the detection end of the detector body 1a. The turntable 2 of the present invention is an air-floating turntable. The air-floating turntables in the prior art can achieve this function. Therefore, the present invention will not repeat the structure of the turntable 2, but it should at least have a shell, a turntable, and a motor or other driving device for driving the turntable to rotate, and the lens B to be detected is placed on the turntable. An air duct is provided on the shell of the turntable 2, one end of the air duct passes through the turntable of the turntable 2, and the other end passes through any surface on the shell. This end is connected to an air pump to form a negative pressure in the air duct, thereby sucking the lens B to be detected. This fixing method of using air pressure to absorb the lens ensures that when the turntable of the turntable 2 rotates, there will be no relative movement between the lens B to be detected and the turntable, so that the lens B to be detected will not be worn. Of course, it is also possible to directly place the lens on the turntable of the turntable 2 without using the adsorption method, and by setting an appropriate surface roughness and a suitable starting torque, the lens B to be detected will not move relative to each other when the turntable rotates.

[0034] In the present invention, a rangefinder 5 is added to detect the horizontal offset of the lens B to be tested due to placement reasons. Therefore, in subsequent calculations, the actual eccentricity can be obtained by directly deducting the horizontal offset from the eccentricity measurement value detected by the eccentricity detector 1. Therefore, each time a new lens is deployed on the turntable 2, there is no need to center the lens, nor is there a need to set a centering device such as a three-jaw clamp or a V-block, which improves the detection efficiency and does not cause wear to the lens due to the clamp itself. Of course, even so, since the detection area of ​​the camera in the eccentricity detector 1 is limited, the horizontal offset should not be too large when placing the lens, and should be adapted to the detection area of ​​the camera used. Figure 1As shown, the turntable 2 is supported on a base 6, which has a certain height. In order to ensure that the light emitted by the rangefinder 5 can be horizontally irradiated on the outer circle of the lens B to be tested, so as to sample points on the outer circle of the lens, and then calculate the horizontal offset through software, the present invention also provides a support device 4 to support the rangefinder 5. In order to enable the support device 4 to adjust the height of the rangefinder 5, the support device 4 of the present invention is a three-axis (three-dimensional) adjustment platform, and the three-axis adjustment platform can be adjusted to make the rangefinder 5 aim at the outer circle of the lens to emit light.

[0035] In the present invention, the eccentricity detector 1 and the rangefinder 5 are both connected to the computer A. The cross light irradiated on the lens by the light source of the eccentricity detector 1 is reflected by the lens (the present invention uses the spherical center reflection principle), and the reflected light converges again to form a spherical center image, which is received by the camera and transmitted to the computer A, and the display of the computer A still displays the cross light.

[0036] Figure 2 FIG. 2 is a schematic diagram showing a detection flow chart of an eccentricity detection device according to an embodiment of the present invention. Figure 1 and Figure 2 When the eccentricity detection device of the present invention is used to detect the eccentricity, the upper and lower mirror surfaces of the lens can be detected separately, or one mirror surface can be detected separately. First, place the lens on the turntable of the turntable. The mirror surface on the upper side is always the mirror surface to be measured. Due to the existence of the horizontal offset, it is necessary to adjust the eccentricity detector 1 so that the light emitted by it converges at the center of curvature of the mirror surface on this side (that is, the extension line of the converged light shines on the center of the lens). During the adjustment process, the display on the computer A can be observed until a cross light appears. As is known to all, lens reflection is divided into mirror reflection and spherical center reflection. The present invention utilizes spherical center reflection, but mirror reflection will also cause a cross light to appear on the display. The difference is that the cross light that appears from mirror reflection is fixed and will not rotate with the rotation of the lens. Therefore, after the cross light appears on the display, the turntable can be rotated to observe whether the cross light moves. If it moves, it can be proved that the cross light is a spherical center image, otherwise it should continue to be adjusted. Then the three-axis adjustment platform (ie, the supporting device 4) is adjusted so that the light emitted by the rangefinder 5 can irradiate the outer circle of the lens, and the reflected light is also received to complete the distance measurement.

[0037] After the above work is completed, the turntable of the turntable 2 can be controlled to rotate (at least one circle). At this time, if the lens has a certain degree of eccentricity, the optical axis of the lens will deviate from the rotation axis of the turntable. Therefore, as the turntable rotates, the cross light on the display of computer A will make a circular motion along a certain radius. The cross light on the display represents the convergence point of the light after being reflected by the lens. Then, the rotation radius can be converted into the eccentricity measurement value through the geometric relationship conversion formula. The specific conversion formula is:

[0038] Eccentricity measurement value = radius / magnification;

[0039] Among them, the radius refers to the radius of the moving track circle of the cross light in the display, and the magnification refers to the magnification of the optical system in the eccentricity detector. It should be noted that since the length of the column 1b is limited, if the radius of curvature of the lens B to be tested is too large, the optical system needs to be replaced to converge the light to the curvature center of the lens. During the rotation of the turntable, the light of the rangefinder 5 is always irradiated on the outer circle of the lens B to be tested. The horizontal offset can be calculated based on the measured value. The calculation formula is:

[0040] Horizontal offset = (maximum value of horizontal distance measurement - minimum value of horizontal distance measurement) / 2;

[0041] The maximum value of the horizontal distance measurement and the minimum value of the horizontal distance measurement refer to the distance measurement values ​​when the distance meter is farthest and closest to the outer circle of the lens to be tested, respectively. The horizontal direction here means that the light emitted by the distance meter 5 is vertically and horizontally irradiated on the outer circle of the lens to be tested. The horizontal offset will be directly transmitted to the computer A (no need to display it), and the computer A will deduct the horizontal offset from the eccentricity measurement to obtain the actual eccentricity of the side mirror, and the calculation formula is:

[0042] Actual eccentricity = measured eccentricity - horizontal offset;

[0043] After the side mirror surface detection is completed, the lens can be turned over, and then the above steps can be repeated to detect the other side. Therefore, the present invention introduces a rangefinder 5 for measuring the horizontal offset of the lens due to placement in the lens eccentricity detection, so that there is no need to set up a separate centering device, thus avoiding wear on the lens, and also eliminating the lens centering process, thereby improving the detection efficiency.

[0044] The above is only one embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for detecting the decentration of a lens, comprising the following steps: a. The eccentricity detection device illuminates the light of the lens to be tested, and the distance measuring device illuminates the outer circle of the lens to be tested; b. Rotate the lens to be tested, and calculate the eccentricity measurement value of the tested mirror surface and the horizontal offset of the lens to be tested based on the light reflected from the tested mirror surface and the outer circle of the lens; c. Calculate the actual eccentricity of the measured mirror using the eccentricity measurement value and the horizontal offset.

2. The eccentricity detection method according to claim 1, characterized in that: In step a, the light irradiated on the measured mirror surface is convergent light, and the extended line of the convergent light irradiates the center of the lens.

3. The eccentricity detection method according to claim 2, characterized in that: In step b, the image formed by the light reflected from the measured mirror surface can rotate as the lens rotates, and the calculation formula of the measured value of the eccentricity is: Eccentricity measurement value = radius / magnification; Among them, the radius refers to the radius of the rotation trajectory circle of the image formed by the light reflected from the measured mirror surface, and the magnification refers to the magnification of the optical system used to converge the light irradiated onto the measured mirror surface.

4. The eccentricity detection method according to claim 3, characterized in that: In step b, the calculation formula of the horizontal offset is: Horizontal offset = (maximum value of horizontal distance measurement - minimum value of horizontal distance measurement) / 2 The maximum value of the horizontal distance measurement and the minimum value of the horizontal distance measurement refer to the distance measurement values ​​when the device for receiving the light reflected from the outer circle of the lens is farthest and closest to the outer circle of the lens, respectively.

5. The eccentricity detection method according to claim 4, characterized in that: The calculation formula of the actual eccentricity in step c is: Actual eccentricity = measured eccentricity - horizontal offset.

6. An eccentricity detection device for a lens, used to implement the eccentricity detection method according to any one of claims 1 to 5, comprising an eccentricity detector (1) and a turntable (2), characterized in that: It also comprises a supporting device (4) and a rangefinder (5) movably arranged on the supporting device (4), wherein light from the rangefinder (5) is irradiated onto the outer circle of the lens to be tested.

7. The eccentricity detection device according to claim 6, characterized in that: The support device (4) is a three-axis adjustment platform or a three-dimensional adjustment platform, and the rangefinder (5) can be adjusted by it so that the emitted light can illuminate the outer circle of the lens to be tested.

8. The eccentricity detection device according to claim 7, characterized in that: The eccentricity detector (1) comprises a detector body (1a) and a column (1b); The detector body (1a) comprises a detection end, a connection end and a dual-axis adjustment platform for driving the detection end to move; The connecting end is connected to the upright column (1b) via a guide rail.

9. The eccentricity detection device according to any one of claims 6 to 8, characterized in that: The turntable (2) is provided with an air passage and an air pump connected to the air passage.

10. The eccentricity detection device according to claim 8, characterized in that: It also includes a base (6) for supporting the column (1b), the turntable (2) and the supporting device (4); The turntable (2) is an air-floating turntable.

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