CN201096611Y - Aspheric lens eccentric measuring apparatus - Google Patents

Abstract

The utility model relates to the optical element detection technical field, in particular to an eccentricity measuring device for an aspheric lens. The eccentricity measuring device aims to solve the problem of low measurement accuracy found in the prior art. The technical proposal adopted by the eccentricity measuring device is that the eccentricity measuring device for the aspheric lens comprises a laser tube and a measured lens whose single surface is aspheric; the spherical surface of the measured lens is fixed on a four-dimensional adjusting frame which is connected with a precise rotary shaft system; the aspheric surface of the lens is arranged on the same side as the laser tube; a beam waist transformation lens is arranged between the laser tube and the measured lens; an image sensor which is vertical to the peak light intensity axial line of the reflective laser is arranged along the reflective surface direction of the measured lens; a lens, a microscopic objective constructed by a lens, a half-transmission half-reflection lens and an image sensor are sequentially arranged on the spherical surface side of the measured lens; a reticle, a ground glass and a light source are sequentially arranged above the half-transmission half-reflection lens; the reticle is positioned on the focal plane of the lens.

Description

A Decentration Measuring Device of Aspherical Lens

Technical field:

The utility model relates to the technical field of optical element detection, in particular to an eccentricity measuring device of an aspheric lens.

Background technique:

At present, domestic aspheric lens manufacturers mainly use dial gauges for contact measurement when measuring the eccentricity of mass-produced aspheric lenses, which often damages the surface of the parts. If the probe of the dial gauge contacts the aspheric surface Add a protective layer (such as thin paper) in between, and the accuracy of the measurement cannot be guaranteed due to the elasticity of the paper. In order to overcome the above-mentioned shortcomings, non-contact measuring devices have become the direction of research. In JP-A-8-233686, an aspheric lens eccentricity measuring device is described. It is a non-contact measuring device. Its working principle Yes: When the detected lens rotates around the mechanical rotation axis, the displacement measurement device records the two-dimensional coordinate change of the laser spot reflected by the aspheric surface on the CCD, and calculates the corresponding eccentricity according to the change amount and the aspheric surface shape. It exists The problem is: because the distance from the incident point of the laser on the aspheric surface to the CCD is very short, the accuracy of the measurement is limited.

Invention content:

The utility model provides an aspheric lens eccentricity measurement device to overcome the problem of insufficient measurement accuracy in the prior art.

In order to overcome the problems existing in the prior art, the technical solution of the present utility model is: a kind of eccentricity measuring device of an aspheric lens, comprising a laser tube 1 and a detected lens 3 whose single surface is an aspheric surface, the spherical surface of the detected lens 3 is a The side is fixed on the four-dimensional adjustment frame 4, the four-dimensional adjustment frame 4 is connected with the precision rotation shaft system 5, the aspheric surface of the lens 3 is on the same side as the laser tube 1, and its special feature is: between the laser tube 1 and the detected lens 3 A beam waist conversion lens 2 is provided, and an image sensor 13 perpendicular to the peak light intensity axis of the reflected laser light is provided on the reflection surface direction of the detected lens 3; 6, the microscope objective lens that lens 7 forms, half mirror 8 and image sensor 9, are provided with reticle 10, frosted glass 11 and light source 12 sequentially above half mirror 8, reticle 10 is positioned at lens 7 on the focal plane.

The aforementioned image sensor 13 and image sensor 9 are CCDs.

The above-mentioned laser tubes 1 can be provided in multiples, and corresponding beam waist transformation lenses 2 and image sensors 13 can also be provided in multiple sets correspondingly.

Compared with the prior art, the utility model has the advantages of:

High sensitivity and good measurement accuracy: This device allows the laser to pass through the beam waist transformation lens, so that the CCD can still receive a small laser spot at a long enough distance, which improves the detection sensitivity and effectively improves the measurement accuracy.

The device can also use multiple laser beams to be incident on the aspheric surface of the detected lens at the same time, and the received image can be calculated and processed to obtain the deviation direction of the symmetry axis of the aspheric surface, which can guide the coincidence of the symmetry axis of the aspheric surface and the mechanical rotation axis The adjustment direction can effectively improve the detection speed of lens eccentricity.

Description of drawings:

Fig. 1 is the schematic diagram of detected lens;

Fig. 2 is a schematic structural view of the utility model.

The reference signs are explained as follows:

1-laser tube, 2-beam waist conversion lens, 3-lens to be detected, 4-four-dimensional adjustment frame, 5-precision rotating shaft, 6-lens, 7-lens, 8-half-transparent mirror, 9-image Sensor, 10-cross reticle, 11-frosted glass, 12-light source, 13-image sensor, 14-computer.

Detailed ways:

The utility model will be described in detail below in conjunction with the accompanying drawings and embodiments.

Referring to FIG. 1 , the figure shows a lens 3 with an aspheric surface on one side. The first surface 3a of the lens 3 to be tested is an aspheric surface, the second surface 3b is a spherical surface, and ia is the symmetry axis of the aspheric surface 3a. Ideally, the center 3ob of the spherical surface 3b of the inspected lens 3 should fall on the symmetry axis ia of the aspheric surface 3a, where ia is the optical axis of the inspected lens 3. However, it is difficult to manufacture such a lens in practice. Usually there is a deviation t between the spherical center 3ob of the spherical surface 3b and the symmetry axis ia of the aspheric surface 3a as shown in FIG. 1 , and this deviation t represents the inherent decentering of the tested lens 3 itself.

Referring to Fig. 2 , an aspheric lens eccentricity measuring device includes a laser tube 1 and a tested lens 3 with an aspheric surface on one side. The spherical side 3b of the tested lens 3 is fixed on a four-dimensional adjustment frame 4 for four-dimensional adjustment. The frame 4 is connected with the precision rotating shaft system 5, and the aspheric surface 3a of the lens 3 is on the same side as the laser tube 1. A beam waist conversion lens 2 is arranged between the laser tube 1 and the detected lens 3, and an image sensor 13 perpendicular to the peak light intensity axis of the reflected laser light is arranged on the reflection surface direction of the detected lens 3. In this embodiment, the image sensor 13 Sensor 13 selects CCD for use. On the spherical side of the detected lens 3, a microscopic objective lens, a half-transparent mirror 8 and an image sensor 9 receiving the reflected image of the center of the sphere are also arranged in sequence. , Lens 7 is composed of, above the half-mirror 8, a reticle 10, a frosted glass 11 and a light source 12 are arranged, and the reticle 10 is located on the focal plane of the lens 7.

Both the image sensor 9 and the image sensor 13 are connected to a computer 14 .

The working principle of the utility model is: the laser beam sent by the laser tube 1 is incident on the surface of the detected aspheric lens 3 through the beam waist conversion lens 2, reflected by the aspheric surface 3a of the lens 3, and received by the image sensor 13. The beam waist, the function of the lens 2 is to transform the beam waist of the laser light onto the photosensitive surface of the image sensor 13 . The detected lens 3 is rotated around the mechanical rotation axis k of the precision rotating shaft system 5, and the yaw rotation of the center position of the laser spot is detected through computer calculation processing, and the detected lens 3 is adjusted by the four-dimensional adjustment frame 4 The position until the center position of the laser spot does not change with the rotation of the lens, indicating that the symmetry axis ia of the aspheric surface 3a coincides with the mechanical rotation axis k of the precision rotation axis system 5 .

In the utility model, a spherical eccentricity measuring instrument is composed of a lens 6, a lens 7, a half mirror, an image sensor 9, a reticle 10, a frosted glass 11 and a light source 12. When the symmetry axis ia of the aspheric surface 3a coincides with the mechanical rotation axis k of the precision rotation axis system 5, adjust the position of the spherical eccentricity measuring instrument so that the light beam emitted from the cross reticle 10 converges on the spherical surface 3b after passing through the microscope objective lens. Near the center of the sphere 3ob, after the light beam is self-collimated and reflected by the sphere 3b, the reflection image of the center of the sphere 3b is obtained on the CCD9. On the axis ia), the detected lens 3 is rotated by the precision rotating shaft system 5, and the reflection image of the center of the sphere is stationary at this time. If there is a deviation between the spherical center 3ob and the mechanical rotation axis k, the reflected image of the spherical center draws a circle on the photosensitive surface of the image sensor 9, and the image sensor 9 inputs the collected information to the computer 14, and obtains the spherical surface 3b through calculation processing The deviation of the spherical center 3ob from the mechanical rotation axis k, that is, the deviation t of the spherical center 3ob from the symmetry axis ia of the aspheric surface 3a, this deviation is the inherent eccentricity of the detected lens 3 itself.

Multiple laser tubes 1 can be provided, and multiple sets of beam waist transformation lenses 2 and image sensors 13 can be provided correspondingly. Each of the plurality of image sensors 13 is connected to a computer 14 .

Claims (3)

1. An aspheric lens eccentricity measuring device, comprising a laser tube (1) and a detected lens (3) with one aspherical surface, the spherical side of the detected lens (3) is fixed on a four-dimensional adjustment frame (4) Above, the four-dimensional adjustment frame (4) is connected with the precision rotating shaft system (5), and the aspherical surface of the lens (3) is on the same side as the laser tube (1), and it is characterized in that: the laser tube (1) and the detected lens (3) ) is provided with a beam waist conversion lens (2), on the direction of the reflective surface of the detected lens (3) is provided with an image sensor (13) that is perpendicular to the peak light intensity axis of the reflected laser light; in the detected lens (3) One side of the spherical surface of ) is also sequentially provided with a microscopic objective lens, a half-mirror (8) and an image sensor (9) made up of a lens (6), a lens (7), at the half-mirror (8) A reticle (10), a frosted glass (11) and a light source (12) are sequentially arranged on the top, and the reticle (10) is located on the focal plane of the lens (7). 2. An aspherical lens eccentricity measuring device according to claim 1, characterized in that: the image sensor (13) and the image sensor (9) are CCDs. 3. The eccentricity measuring device of an aspheric lens according to claim 1 or 2, characterized in that: said laser tube (1) is provided with a plurality of corresponding beam waist transformation lenses (2) and image sensors ( 13) There are multiple groups of corresponding settings.

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