JPS61142407A - Optical displacement measuring device - Google Patents

Abstract

PURPOSE:To enable non-contactig measurement of lens, by arranging a pair of 1st and 2nd optical units at the bottom and on the top of a specimen with the specimen located in-between in such a way than each center line of 3-dimensional optic angle is possessed incommon and installing a means for detecting relative distance along the common center line of the 2nd unit relative to the 1st unit. CONSTITUTION:A pair of 1st and 2nd optical unit 26, 27 are arranged on the and bottom of a specimen with the specimen 18 located in-between in such a way that a center 28 of the 3-dimentional optic angle is possessed in common. And, an optical axis of the specimen 18 is oriented in the proper order on a line 28 for fastening, and by allowing the unit 26 to displace forward and backward relative to the surface 18A, an image developing unit 22 is observed with an observation optical system 24 and slits 13A, 13B of indicating marks 12A, 12B are brought coincidence on the unit 22. Then, a beam of light from projecting and reflecting optical systems 20A, 20B of the unit 26 intersects the surface 18A. Similarly, by allowing the unit 27 to dispalce by a displacing means 31, the beam of light is mode to intersect the surface 18B. At this moment, when a distance between the both units 26,27 is read out from output of a counter 34B in a displacement detecting means 34, the result represents non other than thickness of the specimen 18.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an optical displacement measuring device, and more particularly to an improvement in an optical displacement measuring device for non-contactly measuring the thickness of a lens or the like. I Conventional Technique v/i Conventionally, a micrometer or the like has been used as a means to measure the thickness of a lens. There was a problem that the lens surface was easily damaged, and it could not be used for measuring f and lenses. Also, there were no other suitable measuring instruments for measuring the thickness of these lenses.

[Problems to be solved by the invention]

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide an optical displacement measuring device that can measure the thickness of a lens or the like in a non-contact manner. This invention also applies to objects that cannot be contacted with the probe of a measuring device, such as soft objects, or objects with complex shapes that make it impossible for the probe of a measuring device to reach the measuring point. It is an object of the present invention to provide an optical displacement measuring device that can measure the following in a non-contact manner.

[Means to solve the problem]

In this invention, light rays from a light source are irradiated onto the surface of a measurement object through an index such as a slit, a transflective means, and an objective lens at a stereoscopic viewing angle, and the light rays that have passed through the semi-transmissive reflective means are reflected on the surface. two projection reflection optical systems that reflect the reflected light by the semi-transparent reflection means and guide the reflected light to the same optical axis; a pair of optical units including an observation optical system for forming a superimposed image, and the pair of first and second optical units are used to measure the center line of each of the three-dimensional viewing angles with the object to be measured between them. The first optical unit is disposed below and above the measurement object so as to be shared, and the first optical unit is fixed, and the second optical unit is relatively moved in the vertical direction along the shared center line. unit moving means for holding the object to be measured;
and a measuring object holding means for holding the object in a vertically variable manner at a position between the second optical unit and a displacement detecting means for detecting a relative distance along the shared center line of the second optical unit. The above objective can be achieved regardless of the provision of the above. Further, the above object is achieved by aligning the light input paths of each of the observation optical systems in the first and second optical units on the same optical axis in a substantially vertical direction so that the observation optical systems become one. be. Further, a second optical unit disposed between the first optical unit and the one observation optical system is disposed on the light entrance path of the observation optical system, and the observation optical system The above object is achieved by providing a superimposing transflective means for superimposing the light rays reaching . Further, the above object is achieved by making the superimposing transflective means retractable laterally from the light entrance path. Further, the imaging section in the observation optical system is a parallel plane plate, and the observation optical system achieves the above object by being provided with an eyepiece for viewing the image formed on the parallel plane plate.

[Effect]

In this invention, the first optical unit fixed on the lower side is viewed from below, and the second optical unit provided upwardly and movably in the vertical direction is viewed from above with a stereoscopic viewing angle of the upper and lower surfaces of the object. Irradiates a light beam, confirms from the reflected light that the index is on both surfaces of the object to be measured, and measures the thickness of the object based on the relative distance between both optical units in this state. The measuring object holding means for holding the measuring object is vertically movable,
The lower surface of the object to be measured is aligned with the vertex of the stereoscopic visual field of the irradiated light beam of the first optical unit fixed to the lower side, and the object to be measured is fixedly held at this position. The optical unit is moved up and down so that the apex of the stereoscopic vision of the irradiated light coincides with the top surface of the object to be measured.

【Example】

For convenience of explanation, FIG. 1 shows an embodiment in which the optical system is developed horizontally, and the light rays from the light source 10 are reflected by indicators 12A and 12B consisting of slits, transflective means 14A and 14B, and objective lenses 16A and 16B. The surface of the measurement object 18 is irradiated with a stereoscopic viewing angle through the transmissive reflection means 14A.
, 14B is reflected by the surface of the measuring object 18, and the reflected light is reflected by the semi-transparent reflecting means 14A.
114B and guide the reflected light to the same optical axis, and the indicators 12A, 1 to the same imaging section 22 on the same optical axis.
an observation optical system 24 that forms a superimposed image of 2B;
and the pair of first and second optical units 26 and 27 are connected to the object to be measured 18.
are arranged so as to share the center line 28 of each of the three-dimensional viewing angles 2θ, and the first and second optical units 26 and 27 are moved relative to each other along the shared center line 28. Unit moving means 3o, 31 that can hold the unit
and the object to be measured 18 is connected to the pair of optical units 26.2.
an optical displacement measuring device comprising: a measuring object holding means 32 held at a position between 7 and 7; and a displacement detecting means 34 detecting a relative distance along the shared center 128 of the pair of optical units 26 and 27. It is composed of The two optical units 26 and 27 have the following configurations:
The structure of the first optical unit 26 will be explained and the same reference numerals will be used to describe the structure of the first optical unit 26 since the first optical unit 26 is the same except that the direction of irradiation of the light beam to the measurement object 18 is different. 27 will be omitted. Projection reflection optical system 2OA in first optical unit 26
, 20B are each equipped with right-angle prisms 38A and 38B that capture light rays traveling in opposite directions from the light source 10 via condenser lenses 36A and 136B, and reflect the light in the right angle direction to make parallel light rays. On the parallel optical axes 39A, 39B of the light beams emitted from the right angle prisms 38A, 38B, there are the indicators 12A, 12B.
and the semi-transparent reflection means 14A, 14B are respectively arranged. The indicators 12A, 12B and the right angle prism 38A138B
Green filters 40A and 40B are arranged between them. The indicators 12A and 12B have one slit 13A and two slits 13B formed in parallel on their centers, as shown enlarged in FIGS. 2 and 3, respectively. Furthermore, these indicators 12A, 12B and the semi-transparent reflection means 1
Collimator lenses 42A and 42 are provided between 4A and 14B.
B are arranged respectively. The transflective means 14A and 14B are each formed by attaching two right-angled prisms at their inclined surfaces, and the mating surfaces serve as transflective surfaces. Half of the incident light rays passing through the indicators 12A, 12B and the collimator lenses 42A, 42B pass straight through the semi-transmissive reflective surface, and half of the light rays are directed outward in the width direction in the figure, that is, in a direction away from the other semi-transmissive reflective means. The light is disposed at an angle of 45° with respect to the optical axis 39A139B so that the light is reflected by the light beam. Optical axis 39 passing through the transflective means 14A and 14B
Reflection prisms 44A and 44B are arranged on A and 39B, respectively. -These reflective prisms 4
4A and 44B reflect the incident light beam twice after passing through the transflective means 14A and 14B, and
A and 16B are used to irradiate both surfaces of the measurement object 18 at a stereoscopic viewing angle 2θ centered on the center line 28. A roof beam splitter prism is located between the pair of transflective means 14A, 14B on the optical axis of the light beam reflected inward in the figure on the transflective surface of these transflective means 14A, 14B. 46 are arranged. This roof beam splitter prism 46 superimposes the incident light beams reflected on the semi-transparent reflecting surfaces of the front two semi-transmissive reflecting means 14A and 14B, and
The optical axis 47 is parallel to the optical axes 39A and 39B passing through the optical axis 47, and is arranged so as to emit a light beam onto an optical axis 47 at an intermediate position between the two. A right-angle prism 48 is disposed on the front axis 47 so that the reflective surface on the oblique side thereof intersects the optical axis 47 at an angle of 45°, and one surface facing the inclined surface is perpendicular to the optical axis 47. It is located. The 11 optical measuring system 24 includes a collimator lens 49 disposed on the optical axis 47A reflected by the right angle prism 48;
The imaging section 22 is a parallel plane plate, and the observation system objective lens 50
and an eyepiece lens 52. The above is the configuration of the first optical unit 26. Here, the displacement detecting means 34 includes a unit moving means 30 for reciprocating the first optical unit 26 along the center line 28 and a unit moving means for moving the second optical unit 27 along the center line 28. 31 and an encoder 34A for generating a pulse signal according to the amount of movement along the center line 28 of both;
It is provided with a counter 34B that counts the pulse signal output from 4A. Further, the stereoscopic viewing angle 2θ when the measurement object 18 is irradiated stereoscopically in the optical units 26 and 27 is determined as follows. That is, when the magnification of the objective system is α and the magnification of the eyepiece system is β, the matching accuracy (depth of focus) ΔX in each optical unit 26, 27 is: ΔX −125XΔγ/α・β・sinθ (1)
(Assume Δγ-3o°°) In this case, the matching accuracy ΔX-±0.8μ■, α-1,5,
If β-30, θ is 30°, that is, the stereoscopic viewing angle is 60°. Therefore, in order to obtain a measurement accuracy of about ±1 μ-, the stereoscopic viewing angle is preferably set to 2θ-50 to 70°. Next, a case will be described in which the thickness of the object to be measured 18, which is a lens, is measured in the above embodiment. First, the object to be measured 18 is held and identified by the object holding means 32 so that the central optical axis of the lens, which is the object to be measured, is aligned with the center line 28 . Next, the first optical unit 26 is moved forward and backward with respect to one surface 18A of the measurement object 18, and the imaging section 22 is observed by the observation optical system 24, and the index 1 is placed on the imaging section 22.
The first optical unit 26 is moved until the slits 13A and 13B in 2A and 12B are aligned as shown in FIG. At the point where the indices 12A and 12B coincide, the light beams projected onto the surface 18A of the measurement object 18 from the projection reflection optical systems 2OA and 20B of the first optical unit 26 intersect at the surface 18A. Next, similarly to the first optical unit 26, the second optical unit 27 is moved by the unit moving means 31 and projects light beams from the projection/reflection optical systems 2OA and 20B onto the other surface 18B of the measurement object 18. do. In this case as well, the second optical unit 27 is moved along the center line 28 until the indices 12A and 12B match. The point where the dual-use marks 12A and 12B coincide is the point at which the light beams from the projection reflection optical systems 2OA and 20B reach the other surface 1 of the measurement object 18.
This is the point where they intersect at 8B. At this time, the counter 34B in the displacement detection means 34
If the distance between both optical units 26 and 27 is read from the output of -1, it becomes the thickness of the object 18 to be measured. In this case, with the measurement object 18 removed, for example, the light source 10 in the second optical unit 27 is turned off,
A light beam is projected from the light source 10 of the first optical unit 26 in the direction of the second optical unit 27 by its projection/reflection optical systems 2OA and 20B, and in accordance with this, the second optical unit 27 is directed along the center 1128. In the observation optical system 24 of the second optical unit 27, the index 12A,
12B so that they match, at this point the distance between both optical units 26 and 27 can be set to zero, that is, the zero point can be set. Next, an embodiment of the present invention in an assembled state shown in FIGS. 5 and 6 will be described. In this embodiment, the first optical unit 26 and the second optical unit 27 in the horizontally developed state shown in FIG.
The right angle prism on the optical axis 47 in the reflection optical axis 47A
, 47A are two right-angled prisms 48 and 49 that share the reflecting prisms 44A and 44B. The units 27 are arranged so that the object 18 to be measured is irradiated from above. Further, in this embodiment, since the first optical unit 26 and the second optical unit 27 have a common reflection optical axis 47A, one observation optical system is omitted and only one v
It is possible to observe multiple images using only the A optical measuring system 24. Further, in this embodiment, as described above, two optical units are arranged to share one reflection optical axis 47A, and there is only one observation optical system 24 for these units, and both optical units are arranged to share one reflection optical axis 47A. Since the distances of the units 26 and 27 to the observation optical system 24 are different, in order to compensate for this, distances between the roof beam splitter prism 46 and the right angle prism 48 in the first optical unit 26 and between the first and second optical units are Relay lenses 54A, 54B are arranged between corresponding right angle prisms 48, 49 of 26, 27, respectively. Here, the right angle prism 49 in the second optical unit 27 is slidably attached so that it can be retracted laterally with respect to the reflection optical axis 47A. In addition, the observation optical system 24 in this embodiment includes the first
Unlike the case shown in the figure, the eyepiece lens 52 is arranged perpendicular to the reflection optical axis 47A, and therefore a right-angle prism 56 is arranged on the reflection optical axis. Also, this right angle prism 56 and the upper right angle prism 4
A frimeter lens 58 for converging parallel light rays is arranged between the light beam 8B and the light beam 8B. Further, in this embodiment, the unit moving means 30.
31, the measuring object holding means 32 and the displacement detecting means 34 are mounted on a base 60, as shown in FIG. The base 60 includes a support 60A, and the unit moving means 31 for the second optical unit 27 is attached to be movable in the vertical direction along one side of the support 60A. On the other hand, a unit moving means 30 for supporting the first optical unit 26 is mounted on the base 60 in alignment with and fixed to the unit moving means 31. Further, the measurement object holding means 32, which is a lens holder for holding the measurement object 18, which is a lens, is moved vertically to the support column 60A in alignment with the unit movement means 30131! Ilj is mounted on a freely mounted measuring object stage 62. Further, the encoder 34A at J5 is included in the displacement detecting means 34.
are attached between the non-fixed unit moving means 31 and the support column 60A, and to the object stage 62 and the support column 60AII, respectively. Reference numeral 64 in the figure is a dial for driving the unit moving means 31, 66 is a dial for driving the object stage 62, and 68A and 68B are the respective light sources 10 in the first and second optical units 26 and 27. The lamp house for each is shown. Next, a case will be described in which the thickness of the object to be measured 18, which is a lens, is measured using the apparatus of the above embodiment. In this embodiment, the lower first optical unit 26
is fixed to the base 60, the object to be measured 18 and the second optical unit 27 are moved with this first optical unit 26 as a reference. First, prior to measurement, the light source 1 of the second optical unit 27
0 is turned OFF and the object to be measured 18 is removed, the first optical unit 26 is turned off as in the first embodiment.
The second optical unit 27 receives the light beam projected from the stereoscopic viewing angle 2θ, and the observation optical system 24 observes it.
Confirm the point where 2B matches as the zero point. Next, the object to be measured 18 is placed on the object stage 62, and a light beam is projected from the first optical unit 26 onto the lower surface of the object to be measured 18 at a stereoscopic viewing angle of 2θ. At this time, the right angle prism 49 in the second optical unit I.27 is placed in advance outside the reflection optical axis 47A. indicator 12A of unit 26;
I! in the observation optical system 24 so that 12B matches.
Adjust while measuring. At the point where the indicators 12A and 12B match, the object stage 6
Fix 2. Next, the M2 optical unit 27 illuminates the upper surface of the measurement object 18 at a stereoscopic viewing angle of 2θ. At the same time, the right angle prism 48A is returned to the reflection optical axis 47A,
vinegar. Next, the unit moving means 31 is driven by the dial 64 to move the second optical unit 27 up and down, and while observing with the index 12A, 12Berjl optical measuring system 24, the two indexes 12A, 12B are brought into alignment. . At this point, the counter 34 in the displacement detecting means 34
If the value of B is read, this becomes the thickness of the object 18 to be measured. In the above embodiment, the vAsAAs system 24 is of a visual type including the eyepiece lens 52, but the present invention is not limited to this, and for example, the coincidence of the indicators 12A and 12B can be confirmed using a photoelectric converter or the like. It may be something like that. In this case, the right angle prism 5 in the observation optical system 24
6 can be retracted laterally from the reflection optical axis 47A, and a sensor such as a light receiving element may be provided on an extension of the reflection optical axis 47A. Further, in the above embodiment, the measurement object 18 is a lens-bound 7, but the measurement object can be used, for example, when measuring the sum of the lens thicknesses and distances between lenses of a plurality of lenses attached to lln, or Naturally, it can also be applied to the measurement of soft objects, etc., which cannot be brought into direct contact with the probe.
[Effects of the Invention] Since the present invention is constructed as described above, it has an excellent effect in that the thickness of a lens, etc. can be easily and accurately measured in a non-contact manner.゛・

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the optical system in Embodiment □ of the optical displacement measuring device according to the present invention when it is expanded in the horizontal direction, and Figs. 2 and 3 are enlarged indicators of the same embodiment. 4 is a plan view showing a state in which the indicators match, FIG. 5 is a perspective view showing an embodiment of the present invention, and FIG. 6 is a front view of the same embodiment, not showing the assembled state. It is. 10... Light source, 12A112B... Index, 14A, 14B... Transflective means, 16A, 16B
...Objective lens, 18...Measurement object, 2OA, 20B...Projection reflection optical system, 22...Imaging section, 24...Observation optical system, 26...(first) optics unit, 27... (second) optical unit, 28... center line, 30.31... unit moving means, 32... measuring object holding means, 34... displacement detecting means, 49. ... (for superimposition) transflective means, 50... eyepiece.

Claims (5)

[Claims] (1) A light beam from a light source is irradiated onto the surface of the object to be measured at a stereoscopic viewing angle through an index such as a slit, a transflective means, and an objective lens, and the light beam that has passed through the transflective means is reflected on the surface. two projection reflection optical systems that reflect the generated reflected light by the semi-transmissive reflection means and guide the reflected light to the same optical axis; an observation optical system for forming a multiple image;
The first optical unit is arranged below and above the measurement object so as to share the center line of each of the three-dimensional viewing angles, and the first optical unit is fixed, and the second optical unit is arranged so as to share the center line of each of the stereoscopic viewing angles. unit moving means for holding the object so as to be relatively movable in the vertical direction along the first and second
a measuring object holding means for holding the object in a vertically variable manner at a position between the optical units; and a displacement detection unit for detecting a relative distance of the second optical unit to the first optical unit along the shared center line. An optical displacement measuring device comprising: means. (2) The light input paths of the respective observation optical systems in the first and second optical units are aligned on the same optical axis in a substantially vertical direction, so that there is one observation optical system. Optical displacement measuring device described in Section 2. (3) A second optical unit disposed between the first optical unit and the one observation optical system is disposed on the light entrance path of the observation optical system, and the second optical unit is disposed between the first optical unit and the one observation optical system. 3. The optical displacement measuring device according to claim 2, comprising a superimposing transflective means for superimposing the light beams reaching the system. (4) The optical displacement measuring device according to claim 3, wherein the superimposing semi-transparent reflection means can be retracted laterally from the light entrance path. (5) The imaging section in the observation optical system is a parallel plane plate, and the observation optical system is provided with an eyepiece for visually observing the image formed on the parallel plane plate. The optical displacement measuring device according to item 2, 3, or 4.