JPH0315128B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical displacement measuring device, and particularly to an improvement in an optical displacement measuring device for non-contact measuring the thickness of a lens or the like.

[Conventional technology]

Conventionally, a micrometer or the like has been used as a means to measure the thickness of a lens, but since this brings a metal spindle into direct contact with the lens surface, it is easy to damage the lens surface.
There was a problem that it could not be used to measure FE lenses.

Also, there was no other suitable measuring device for measuring the thickness of these lenses.

[Problem that the invention seeks to solve]

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 without contact.

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 for solving problems]

This invention irradiates a light beam from a light source through an indicator such as a slit, a transflective means, and an objective lens onto the surface of a measurement object at a stereoscopic viewing angle, and the light beam that passes through the semitransparent reflective means is reflected on the surface. 2. Reflecting the reflected light generated by the transmissive reflection means, and guiding the reflected light to the same optical axis.
a pair of optical units including a projection reflection optical system and an observation optical system that forms a superimposed image of the target on the same imaging section on the same optical axis;
The pair of first and second optical units are disposed below and above the object to be measured, with the object to be measured in between, so as to share the center line of each of the three-dimensional viewing angles, and Fix the unit and
and unit moving means for holding the second optical unit so as to be relatively movable in the vertical direction along the shared center line; The above object is achieved by providing a measuring object holding means for holding the object in a variable vertical position, and a displacement detecting means for detecting a relative distance along the shared center line of the second optical unit. .

Further, the above object is achieved by aligning the light input paths of the respective observation optical systems in the first and second optical units on the same optical axis in the substantially vertical direction, and using the observation optical systems as one. be.

Further, a second optical unit disposed between the first optical unit and the one observation optical system is disposed on the light input path of the observation optical system, and a second optical unit is disposed between the first optical unit and the one observation optical system. The above object is achieved by providing a superimposing transflective means for superimposing the light rays that reach .

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 provides a stereoscopic viewing angle from below to the upper surface and the lower surface of the object to be measured, and the second optical unit provided above to be movable in the vertical direction provides a stereoscopic viewing angle from above. From the reflected light, the index is
A workpiece holding means for holding the workpiece, which measures the thickness of the workpiece based on the relative distance between both optical units in this state after confirming that the optical units are on both surfaces of the workpiece. is movable in the vertical direction, and fixes and holds the object to be measured at this position by aligning the lower surface of the object to be measured with the vertex of the stereoscopic vision of the irradiated light beam of the first optical unit fixed to the lower side. death,
On the other hand, the upper second optical unit is moved up and down so that the apex of the stereoscopic vision of its projection light beam coincides with the upper 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 lens 16A. ,16
The surface of the object to be measured 18 is irradiated with a stereoscopic viewing angle through B, and the reflected light generated when the light beams that have passed through the transflective means 14A and 14B are reflected on the surface of the object to be measured 18 is reflected by the transflective means 14.
Two projection reflection optical systems 20A, which reflect the reflected light by A and 14B and guide the reflected light to the same optical axis.
20B and the same imaging section 22 on the same optical axis.
a pair of optical units including an observation optical system 24 for forming a superimposed image of the indicators 12A, 12B, and the pair of first and second optical units 26, 27 are connected to the object 18 to be measured. are arranged so as to share the center line 28 of each of the three-dimensional viewing angles 2θ, and the first and second
unit moving means 30, 31 for holding the optical units 26, 27 so as to be relatively movable along the shared center line 28; An optical displacement measuring device is constituted by a measuring object holding means 32 for holding the object to be measured, and a displacement detecting means 34 for detecting the relative distance along the shared center line 28 of the pair of optical units 26 and 27. be.

The two optical units 26 and 27 have the same configuration except that the direction of irradiation of the light beam onto the measurement object 18 is different. Therefore, the configuration of the first optical unit 26 will be explained, and the following description will explain the configuration of the first optical unit 26. By assigning the same reference numerals, a description of the first optical unit 27 will be omitted.

Projection/reflection optical systems 20A and 20B in the first optical unit 26 respectively transmit light rays traveling in opposite directions from the light source 10 to the condenser lens 36.
Right angle prisms 38A, 38B capture the light through A, 36B and reflect it in the right angle direction to make parallel light beams.
Each is equipped with

On the parallel optical axes 39A, 39B of the light beams emitted from the right angle prisms 38A, 38B, the indicators 12A, 12B and the transflective means 14A,
14B are arranged respectively.

The indicators 12A, 12B and the right angle prism 38
Green filters 40A and 4 are installed between A and 38B.
0B are arranged respectively.

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, collimator lenses 42A and 42B are arranged between these indicators 12A and 12B and the transflective means 14A and 14B, 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 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 optical axis 39A,
It is placed at 45 degrees to 39B.

A reflecting prism 44 is disposed on the optical axis 39A, 39B that has passed through the semi-transparent reflecting means 14A, 14B.
A and 44B are arranged respectively.

These reflecting prisms 44A, 44B reflect twice the light beams that have passed through the semi-transmissive reflecting means 14A, 14B, and
The center line 28 is attached to both sides of the measurement object 18 via
The beam is irradiated with a stereoscopic viewing angle of 2θ centered at .

These semi-transparent reflecting means 14A, 14 are located between the pair of semi-transmissive reflecting means 14A, 14B.
A roof beam splitter prism 46 is disposed on the optical axis of the light beam reflected inwardly in the figure at the semi-transmissive reflective surface B.

This roof beam splitter prism 46 superimposes the incident light beams reflected on the semi-transparent reflecting surfaces of the semi-transmissive reflecting means 14A, 14B, so that the optical axes 39A, 39B pass through the indicators 12A, 12B.
an optical axis 4 that is parallel to and intermediate between the two.
7 so as to emit a light beam.

On this optical axis 47, a right-angle prism 48 has a reflective surface on its oblique side intersecting the optical axis 47 at an angle of 45 degrees, and one surface facing the inclined surface is perpendicular to the optical axis 47. It is arranged so that

The observation optical system 24 includes the right angle prism 48
It is composed of a collimator lens 49 disposed on a reflection optical axis 47A, the imaging section 22 which is a parallel plane plate, an 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 the center line 28 of both
The encoder 34A generates a pulse signal according to the amount of movement along the encoder 34A, and the counter 34B counts the pulse signal output from the encoder 34A.

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 as follows: Δx=125×Δγ/α・β・sinθ…(1) (Assume Δγ=30″) In this case, matching accuracy Δx=±0.8μm, α=1.5,
When β=30, θ is 30°, that is, the stereoscopic viewing angle is 60°. Therefore, in order to obtain a measurement accuracy of about ±1 μm, the stereoscopic viewing angle 2θ is preferably set to 50 to 70°.

Next, in the above embodiment, the measurement object 1 which is a lens
The case of measuring the thickness of No. 8 will be explained.

First, the measurement object 18 is held and fixed by the measurement object holding means 32 so that the central optical axis of the lens, which is the measurement object 18, 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 object to be measured 18, and the observation optical system 24 is used to observe the imaging section 22. The first optical unit 26 is moved until the slits 13A and 13B in the slits 12A and 12B are aligned as shown in FIG. Indicator 1
At the point where 2A and 12B coincide, the light rays projected from the projection reflection optical systems 20A and 20B of the first optical unit 26 onto the surface 18A of the measurement object 18
They will intersect at A.

Next, similarly to the first optical unit 26,
The second optical unit 27 is moved to the unit moving means 3.
1, the projection/reflection optical systems 20A and 20B project light beams onto the other surface 18B of the measurement object 18.

In this case as well, indicators 12A and 12B
The second optical unit 27 is moved along the center line 28 until they match.

The point where both indicators 12A and 12B coincide is the point where the light beams from the projection reflection optical systems 20A and 20B reach the measurement object 18.
This is the point where they intersect on the other surface 18B.

At this time, from the output of the counter 34B in the displacement detecting means 34, both optical units 26, 27
If the distance between them is read, it becomes the thickness of the object 18 to be measured.

In this case, with the object to be measured 18 removed, the light source 10 in the second optical unit 27 is turned off, and the light beam is transmitted from the light source 10 of the first optical unit 26 by its projection/reflection optical system 20A, 20B. is projected in the direction of the second optical unit 27, the second optical unit 27 is moved along the center line 28, and the observation optical system 24 of the second optical unit 27 projects the index. 12
When adjusting so that A and 12B match, at this point the distance between both optical units 26 and 27 is zero,
That is, it is possible to set a zero point.

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 deployed state shown in FIG. The upper right-angle prism is replaced by two right-angle prisms 48 and 49 that share the reflection optical axes 47A and 47A, and the reflection prisms 44A and 44B are used to irradiate the object to be measured 18 from below in the first optical unit 26. In addition, the second optical unit 27 is arranged so as to irradiate the object 18 from above.

Furthermore, 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 observation optical system 24 is used. This makes it possible to observe multiple images.

Further, in this embodiment, as described above, two optical units are arranged to share one reflection optical axis 47A, and the observation optical system 2 is connected to these units.
4 is one piece, and the distances of both the optical units 26 and 27 to the observation optical system 24 are different. To compensate for this, the roof beam splitter prism 46 and the right angle prism 48 in the first optical unit 26 are different. Relay lenses 54A and 54B are arranged between the two optical elements and between the corresponding right angle prisms 48 and 49 of the first and second optical units 26 and 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.

Furthermore, the observation optical system 24 in this embodiment includes:
Unlike the case of FIG. 1, 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.

A collimator lens 58 for converging parallel light rays is disposed between this right-angle prism 56 and the upper right-angle prism 48B.

Further, in this embodiment, the unit moving means 30, 31, the object holding means 32, and the displacement detecting means 34 are mounted on a base 6, as shown in FIG.
It is installed on 0.

The base 60 is provided with a support 60A, and a unit moving means 31 for the second optical unit 27 is mounted so as to be movable in the vertical direction along one side of the support 60A.

On the other hand, the unit moving means 30 for supporting the first optical unit 26 is mounted on the base 60.
It is fixedly mounted on the top in alignment with the unit moving means 31.

Further, a measuring object holding means 32 serving as a lens holder for holding the measuring object 18 serving as a lens is attached to the supporting column 60A by the unit moving means 30, 3.
The measuring object stage 62 is mounted on a measuring object stage 62 which is aligned with the object stage 1 and is mounted so as to be movable in the vertical direction.

Further, the encoder 34A in the displacement detecting means 34 is installed between the non-fixed unit moving means 31 and the support column 60A, and between the object stage 62 and the support column 60A.

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, since the lower first optical unit 26 is fixed to the base 60, the object to be measured is
8 and the second optical unit 27.

First, prior to measurement, the second optical unit 27
With the light source 10 turned off and the object to be measured 18 removed, the stereoscopic viewing angle 2 projected from the first optical unit 26 is determined as in the first embodiment.
The light beam of θ is received by the second optical unit 27, observed by the observation optical system 24, and then
Indicators 12A and 12B in the optical unit 26 of
Confirm the point that matches as the zero point.

Next, the object 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 18 at a stereoscopic viewing angle 2θ.

At this time, the right angle prism 49 in the second optical unit 27 is placed in advance outside the reflection optical axis 47A.

In this state, move the object stage 62 to the dial 66.
The first optical unit 26 is moved up and down by the
Adjustments are made while observing in the observation optical system 24 so that the indices 12A and 12B match.

The object stage 62 is fixed at the point where the indicators 12A and 12B match.

Next, the second optical unit 27 illuminates the upper surface of the object 18 at a stereoscopic viewing angle 2θ.

At the same time, the right angle prism 48A is reflected by the optical axis 47A.
Return to top.

Next, the unit moving means 31 is driven by the dial 64 to move the second optical unit 27 up and down, and move the indicators 12A and 12B to the observation optical system 2.
While observing at step 4, both indicators 12A and 12B are made to match.

At this point, if the value of the counter 34B in the displacement detecting means 34 is read, this becomes the thickness of the object 18 to be measured.

In the above embodiment, the observation optical system 24 is of a visual type including the eyepiece lens 52.
The present invention is not limited to this, and for example, a photoelectric converter or the like may be used to confirm whether the indicators 12A and 12B match.

In this case, it is preferable that the right-angle prism 56 in the observation optical system 24 is retractable laterally from the reflection optical axis 47A, and a sensor such as a light receiving element is provided on the extension of the reflection optical axis 47A.

Further, in the above embodiment, the measurement object 18 is a lens, 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 a lens barrel, or Naturally, it can also be applied to the measurement of soft objects, etc., which cannot be brought into direct contact with the probe.

[Effect of idea]

Since the present invention is configured as described above, it has an excellent effect in that the thickness of a lens or the like can be easily and accurately measured without contact.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an optical system in an embodiment of the optical displacement measuring device according to the present invention, in a horizontally developed state, and FIGS. 2 and 3 are enlarged views of indicators in the same embodiment. FIG. 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 showing the assembled state of the embodiment. 10... Light source, 12A, 12B... Index, 14
A, 14B...Transflective means, 16A, 16B
...Objective lens, 18...Measurement object, 20A, 20
B... Projection reflection optical system, 22... Imaging section, 24...
...observation optical system, 26... (first) optical unit, 27... (second) optical unit, 28...
Center line, 30, 31...Unit moving means, 32
...Measurement object holding means, 34...Displacement detection means, 4
9... (for superimposition) semi-transparent reflection means, 50... eyepiece.

Claims (1)

[Scope of 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 semi-transmissive reflecting means, and an objective lens, and the light beam passing through the semi-transmissive reflecting means illuminates the surface. Reflecting the reflected light generated by reflection at the semi-transparent reflecting means,
and two projection reflection optical systems that guide the reflected light to the same optical axis, and an observation optical system that forms a superimposed image of the index on the same imaging section on the same optical axis. a pair of first and second optical units are arranged below and above the object to be measured, with the object to be measured in between so as to share the center line of each of the three-dimensional viewing angles; unit moving means for fixing the first optical unit and holding the second optical unit so as to be relatively movable in the vertical direction along the shared center line; a measuring object holding means that holds the object in a vertically variable manner at a position between the first and second optical units; and a relative distance of the second optical unit to the first optical unit along the shared center line. An optical displacement measuring device comprising: displacement detecting means for detecting displacement. 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 the substantially vertical direction, so that there is one observation optical system as described in claim 1. optical displacement measuring device. 3. A second optical unit disposed between the first optical unit and the one observation optical system,
The optical system according to claim 2, further comprising a superimposing transflective means disposed on the light input path of the observation optical system for superimposing light rays from both optical units to the observation optical system. Displacement measuring device. 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. Claim 2, characterized in that the imaging section in the observation optical system is a parallel plane plate, and the observation optical system is equipped with an eyepiece for visually observing the image formed on the parallel plane plate. , the optical displacement measuring device according to item 3 or 4.