Auto-collimation laser triangular lens thickness measuring device and method

Abstract

The invention provides an auto-collimation laser triangular lens thickness measuring device. The auto-collimation laser triangular lens thickness measuring device comprises a laser light source, a spectroscope, an emergent lens, a plane mirror, a light spot acquisition mechanism, a receiving lens and a light spot position detection mechanism, the spectroscope and the emergent lens are sequentially arranged on an emitting light path of the laser light source; the plane mirror and the light spot acquisition mechanism are respectively arranged on two sides of the spectroscope; a laser beam emitted by the laser light source irradiates the spectroscope, passes through the spectroscope and the emergent lens, then irradiates the surface of a measured object, sequentially passes through the emergent lens and the spectroscope after being reflected, and is refracted on the light spot acquisition mechanism through the spectroscope to form a first light spot; a laser beam emitted by the laser light source irradiates the spectroscope, vertically irradiates the plane mirror through refraction, and passes through the spectroscope again through reflection to form a second light spot on the light spot acquisition mechanism. According to the invention, auto-collimation can be realized, the debugging process is reduced, and the measurement precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical measurement, and particularly relates to a self-collimating laser triangulation lens thickness measurement device and method. Background Art

[0002] Optical lenses are made of glass or polymeric materials, and high-quality optical lenses have strict tolerance limits. The central thickness of a lens is an important parameter of an optical system, and the quality of its processing will have a great impact on the imaging quality of the optical system, directly affecting parameters such as the focal length and radius of curvature of the lens. Therefore, the central thickness of the lens is a very important parameter for the optical system. The installation and debugging process of existing detection instruments is very complex and requires a lot of time and energy for collimation adjustment. The present invention provides a high-precision, high-efficiency, non-contact lens central thickness detection system and method. Summary of the Invention

[0003] The present invention solves the defects of the complex debugging process, poor accuracy and low efficiency in the existing lens thickness measurement, and provides a self-collimating laser triangulation lens thickness measurement device and method.

[0004] The technical solution of the present invention is as follows:

[0005] A self-collimating laser triangulation lens thickness measurement device includes a laser light source, a beam splitter, an exit lens, a plane mirror, a spot collection mechanism, a receiving lens, and a spot position detection mechanism;

[0006] The beam splitter and the exit lens are sequentially arranged on the light path emitted by the laser light source; the plane mirror and the spot collection mechanism are respectively arranged on both sides of the beam splitter;

[0007] The laser beam emitted by the laser light source irradiates the beam splitter, passes through the beam splitter to form a first path of light, passes through the exit lens and then irradiates the surface of the object to be measured, and after reflection, passes through the exit lens and the beam splitter in sequence, and forms a first spot on the spot collection mechanism through the refraction of the beam splitter;

[0008] The laser beam emitted by the laser light source irradiates the beam splitter, is refracted and vertically irradiates the plane mirror, and after reflection, passes through the beam splitter again to form a second spot on the spot collection mechanism;

[0009] The receiving lens is arranged on the diffuse reflection light path of the object to be measured, and the spot position detection mechanism is arranged behind the receiving lens for detecting the position of the spot converged by the receiving lens.

[0010] Preferably, the spot collection mechanism is a CCD camera.

[0011] Preferably, the spot position detection mechanism is a CCD camera.

[0012] Preferably, the spot position detection mechanism is a PSD (Position Sensitive Detector) optical position sensitive device.

[0013] An auto - collimation laser triangulation lens thickness measurement method includes the following steps:

[0014] Step 1: Use the above - mentioned auto - collimation laser triangulation lens thickness measurement device, arrange two sets of auto - collimation laser triangulation lens thickness measurement devices symmetrically, and make the optical paths emitted by the laser light sources in the two sets of measurement devices coincide.

[0015] Step 2: Place a standard gauge block at the detection position, and the upper and lower surfaces of the standard gauge block are parallel; by adjusting the position and angle of the standard gauge block, make the two spots collected by the spot collection mechanism in one set of auto - collimation laser triangulation lens thickness measurement devices coincide; at this time, record the spot position measured by the spot position detection mechanism.

[0016] Step 3: Remove the standard gauge block and place the lens to be measured at the detection position, adjust the angle and position of the lens to be measured, make the two spots collected by the spot collection mechanism in one set of auto - collimation laser triangulation lens thickness measurement devices coincide; at this time, record the spot position measured by the spot position detection mechanism.

[0017] Step 4: By comparing and analyzing the changes in the spot positions measured by the spot position detection mechanism in Step 2 and Step 3, calculate the central thickness of the lens to be measured.

[0018] Preferably, compare the spot positions measured by the spot position detection mechanism in Step 2 and Step 3, record the displacement of one of the spots as δ, and calculate the displacement Δ1 between the measurement point on one side of the lens to be measured and the same - side measurement point of the standard gauge block as:

[0019]

[0020] Where:

[0021] a - The distance from the intersection of the optical axis of the laser beam and the optical axis of the receiving lens to the front principal point of the objective lens;

[0022] b - The distance from the rear principal point of the receiving lens to the center point of the spot position detection mechanism;

[0023] θ - The angle between the optical axis of the laser beam and the optical axis of the receiving transparent;

[0024] α - The angle between the receiving lens and the photosensitive surface of the spot position detection mechanism;

[0025] Similarly, calculate the displacement Δ2 between the measurement point on the other side of the lens to be measured and the same - side measurement point of the standard gauge block;

[0026] L = D-(Δ1 + Δ2)

[0027] Where D is the thickness of the standard gauge block.

[0028] The beneficial effects of the present invention are as follows: The self-aligning laser triangulation lens thickness measurement device and method provided by the present invention have high imaging quality and sensitivity, and can improve the alignment and measurement accuracy. The present invention has the characteristics of simple structure, high precision, high efficiency, non-contact, etc., and is mainly applied to the field of optical lens parameter detection. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of a self-aligning laser triangulation lens thickness measurement device.

[0030] Figure 2 It is a schematic diagram of the self-aligning principle of a self-aligning laser triangulation lens thickness measurement device.

[0031] Figure 3 It is a schematic diagram of the measurement principle of a self-aligning laser triangulation lens thickness measurement device.

[0032] Figure 4 It is a schematic diagram of the standard gauge block measurement.

[0033] Figure 5 It is a schematic diagram of the measured lens measurement. Detailed Embodiments

[0034] The following further detailed description of the present invention is provided to enable those skilled in the art to implement it according to the text of the specification.

[0035] The present invention provides a self-aligning laser triangulation lens thickness measurement device 100, as Figure 1 shown, which includes a laser light source 1, a beam splitter 2, an exit lens 3, a plane mirror 4, a spot collection mechanism 5, a receiving lens 6, and a spot position detection mechanism 7 provided in a housing 10.

[0036] Refer to Figure 2, the beam splitter 2 and the exit lens 3 are sequentially arranged on the light path emitted by the laser light source 1. A plane mirror 4 is arranged on the right side of the beam splitter 2, and a spot acquisition mechanism 5 is arranged on the left side of the beam splitter 2. The laser beam emitted by the laser light source 1 irradiates on the beam splitter 2, and after beam splitting, a first path of light that passes straight through the beam splitter 2 and a second path of light perpendicular to the first path of light are formed. The first path of light irradiates on the surface of the object to be measured 8 after passing through the exit lens 3, and the second path of light irradiates vertically on the plane mirror 4. The exit lens 3 is used to collimate the received laser. After the first path of light irradiates on the surface of the object to be measured 8, it is reflected and then passes through the exit lens 3 and the beam splitter 2 in sequence, and a first spot is formed on the spot acquisition mechanism 5 on the left side through the beam splitting action of the beam splitter 2. After the second path of light irradiates vertically on the plane mirror 4, it is reflected and passes through the beam splitter 2 again, and a second spot is formed on the spot acquisition mechanism 5 after passing straight through the beam splitter 2. The spot acquisition mechanism 5 can acquire the positions of the first spot and the second spot.

[0037] The spot acquisition mechanism 5 can be set as a CCD camera, and the position of the spot can be acquired by recording the image of the spot through the CCD camera.

[0038] If the object to be measured 8 is a flat lens, when the upper surface of the object to be measured 8 is perpendicular to the first path of light, the first path of light irradiates on the upper surface of the object to be measured 8 and is reflected vertically back along the original path. At this time, the first spot formed on the spot acquisition mechanism 5 will coincide with the second spot. Therefore, in the self-collimation type laser triangular lens thickness measuring device 100 provided by the present invention, before measurement, by adjusting the angle of the flat lens object to be measured 8, the first spot will coincide with the second spot, thereby ensuring that the upper surface of the object to be measured 8 is perpendicular to the optical axis of the laser light source 1, preventing the object to be measured 8 from being placed crooked, and further affecting the measurement result.

[0039] If the object to be measured 8 is a curved lens, when the first path of light irradiates on the vertex of the curved lens and the central optical axis of the curved lens coincides with the first path of light, the first path of light is reflected vertically back along the original path. At this time, the first spot formed on the spot acquisition mechanism 5 will coincide with the second spot. Therefore, in the self-collimation type laser triangular measuring device provided by the present invention, before measurement, by adjusting the position and angle of the curved lens object to be measured 8, the first spot will coincide with the second spot, thereby ensuring that the first path of light is reflected vertically back along the original path, that is, the measurement position is the vertex of the curved lens at this time, and the curved lens is not placed crooked.

[0040] Through the setting of the above structure, self-collimation is achieved, the object to be measured 8 is placed in the correct position, which is convenient for the subsequent accurate measurement of the central thickness of the lens.

[0041] The present invention further includes a receiving lens 6 and a spot position detection mechanism 7. When the first path of light irradiates the upper surface of the object to be measured 8, the formed diffuse reflection light is displayed on the spot position detection mechanism 7 after passing through the receiving lens 6. The spot position detection mechanism 7 employs a CCD camera or a PSD (Position Sensitive Detector) device, which can accurately detect the position of the spot. When the position of the upper surface of the object to be measured 8 changes, the position of the spot on the spot position detection mechanism 7 also changes accordingly. By detecting the change amount of the spot position on the spot position detection mechanism 7, the change amount of the upper surface position of the object to be measured 8 can be calculated. By symmetrically arranging two sets of autocollimation laser triangular lens thickness measurement devices 100, the measurement of the thickness of the object to be measured 8, i.e., the lens, can be achieved.

[0042] As Figure 3 shown, the present invention also provides an autocollimation laser triangular lens thickness measurement method. The specific measurement principle and method are as follows:

[0043] Symmetrically arrange two sets of autocollimation laser triangular lens thickness measurement devices 100 so that the optical paths emitted by the laser light sources 1 in the two sets of measurement devices 100 coincide. Place a standard gauge block 81 at the detection position. The standard gauge block 81 is a plane lens with parallel upper and lower surfaces. By adjusting the position and angle of the standard gauge block 81, make the two spots collected by the spot collection mechanism 5 in the autocollimation laser triangular lens thickness measurement device 100 coincide. At this time, it indicates that the upper and lower surfaces of the standard gauge block 81 are perpendicular to the optical axis of the laser light source 1. At this time, the position adjustment work of the standard gauge block 81 is completed.

[0044] As Figure 4 shown, taking the measurement of the upper surface of the standard gauge block 81 as an example, the laser beam emitted by the laser light source 1 linearly passes through the beam splitter 2 and the exit lens 3 and vertically irradiates the upper surface of the standard gauge block 81. The formed scattered light is converged by the receiving lens 6 and imaged on the spot position detection mechanism 7. Record the imaging center point at this time as position A.

[0045] As Figure 5As shown, remove the standard gauge block 81 and replace it with the lens under test 82. Taking the lens under test 82 as an arc lens as an example, by adjusting the angle and position of the lens under test 82, make the two light spots collected by the light spot acquisition mechanism 5 in the self-collimation laser triangular lens thickness measurement device 100 coincide. At this time, it indicates that the axis of the lens under test 82 coincides with the optical axis of the laser light source 1. The first light path irradiates the vertex of the arc surface of the lens under test 82. At this time, the scattered light formed passes through the convergence of the receiving lens 6 and is imaged on the light spot position detection mechanism 7, and record this time as position B. At this time, the leftward movement of position B relative to position A indicates that the upper measurement point of the lens under test 82 moves downward relative to the upper measurement point of the standard gauge block 81. By comparing position A and position B, the distance between position A and position B is obtained as δ, and δ is a positive number. If position B moves to the right relative to position A, then δ is taken as a negative number. Through analysis and calculation, the displacement Δ1 between the upper measurement point of the lens under test 82 and the upper measurement point of the standard gauge block 81 can be obtained as:

[0046]

[0047] Since θ + α = 90° in the formula, the above formula can be simplified to:

[0048]

[0049] a——The distance from the intersection of the optical axis of the laser beam and the optical axis of the receiving lens to the front principal point of the objective lens;

[0050] b——The distance from the rear principal point of the receiving lens to the center point of the light spot position detection mechanism;

[0051] θ——The angle between the optical axis of the laser beam and the optical axis of the receiving transparent lens;

[0052] α——The angle between the receiving lens and the photosensitive surface of the light spot position detection mechanism.

[0053] Similarly, through another set of self-collimation laser triangular lens thickness measurement devices 100, repeat the above steps to measure the displacement Δ2 between the lower measurement point of the lens under test 82 and the lower measurement point of the standard gauge block 81.

[0054] Finally, the thickness L of the lens under test 82 is obtained as:

[0055] L = D - (Δ1 + Δ2), where D is the thickness of the standard gauge block 81.

[0056] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. A self-aligning laser triangulation lens thickness measuring device, characterized in that, It includes a laser light source, a beam splitter, an exit lens, a plane mirror, a spot collection mechanism, a receiving lens, and a spot position detection mechanism; The beam splitter and the exit lens are sequentially arranged on the light path emitted by the laser light source; the plane mirror and the spot collection mechanism are respectively arranged on both sides of the beam splitter; The laser beam emitted by the laser light source irradiates the beam splitter, passes through the beam splitter to form a first path of light, irradiates the surface of the object to be measured after passing through the exit lens, and after reflection, sequentially passes through the exit lens and the beam splitter, and forms a first spot on the spot collection mechanism through the refraction of the beam splitter; The laser beam emitted by the laser light source irradiates the beam splitter, is refracted and vertically irradiates the plane mirror, and after reflection, passes through the beam splitter again to form a second spot on the spot collection mechanism; The receiving lens is arranged at the diffuse reflection light path of the object to be measured, and the spot position detection mechanism is arranged behind the receiving lens to detect the spot position converged by the receiving lens.

2. The self-aligning laser triangle lens thickness measuring device according to claim 1, characterized in that The spot collection mechanism is a CCD camera.

3. The self-aligning laser triangulation lens thickness measuring device according to claim 1, wherein The spot position detection mechanism is a CCD camera.

4. The self-aligning laser triangulation lens thickness measuring device according to claim 1, characterized in that, The spot position detection mechanism is a PSD (Position Sensitive Detector) optical position sensitive device.

5. A method for measuring the thickness of a self-aligning laser triangular lens, characterized in that, It includes the following steps: Step 1: Use the self-aligning laser triangulation lens thickness measurement device as described in claims 1-4, arrange two sets of self-aligning laser triangulation lens thickness measurement devices symmetrically, and make the light paths emitted by the laser light sources in the two sets of measurement devices coincide; Step 2: Place the standard gauge block at the detection position, and the upper and lower surfaces of the standard gauge block are parallel; by adjusting the position and angle of the standard gauge block, make the two spots collected by the spot collection mechanism in one set of self-aligning laser triangulation lens thickness measurement devices coincide; at this time, record the spot position measured by the spot position detection mechanism; Step 3: Remove the standard gauge block and place the lens to be measured at the detection position, adjust the angle and position of the lens to be measured, and make the two spots collected by the spot collection mechanism in one set of self-aligning laser triangulation lens thickness measurement devices coincide; at this time, record the spot position measured by the spot position detection mechanism; Step 4: By comparing and analyzing the changes in the spot positions measured by the spot position detection mechanism in Step 2 and Step 3, calculate the central thickness of the lens to be measured.

6. The self-aligning laser triangulation lens thickness measurement method according to claim 5, characterized in that, Compare the spot positions measured by the spot position detection mechanism in Step 2 and Step 3, record the displacement of one of the spots as δ, and calculate the displacement Δ1 between the measurement point on one side of the lens to be measured and the same-side measurement point of the standard gauge block as: Where: a - The distance from the intersection of the optical axis of the laser beam and the optical axis of the receiving lens to the front principal point of the objective lens; b - The distance from the rear principal point of the receiving lens to the center point of the spot position detection mechanism; θ - The angle between the optical axis of the laser beam and the optical axis of the receiving lens; α - The angle between the receiving lens and the photosensitive surface of the spot position detection mechanism; Similarly, calculate the displacement Δ2 between the measurement point on the other side of the lens to be measured and the same-side measurement point of the standard gauge block; L = D - (Δ1 + Δ2) Where D is the thickness of the standard gauge block.

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