JPS62172207A - Optical measuring apparatus - Google Patents

Abstract

PURPOSE:To prevent lowering in measuring accuracy caused by the thermal expansion and contraction of a collimator lens, by correcting the focus of the collimator lens by forming a lens holding member so as to enable the same to thermally extend and contract along the optical axis of the collimator lens. CONSTITUTION:A laser beam emitter 50 is constituted of a laser beam emitting semiconductor 52, a collimator lens 54 made of a synthetic resin for converting the beam from said semiconductor 52 to parallel beam having a predetermined cross-sectional shape,and a lens holding member 56 supporting said lens and formed so as to be made thermally expandable and contractable along the optical axis of the lens 54 so as to correct the focus of the lens 54 changing with change in temp. The member 56 is constituted of a first cylindrical body 60 and a second cylindrical body 62. The cylindrical body 62 is formed of a material having coefficient of linear expansion smaller than that of the cylindrical body 60 and mounted to the cylindrical body 62 in a thermally pandable and contractable manner on the basis of the leading end side of the cylindrical body 60. By this constitution, even if the lens 54 is made of the synthetic resin, the variation in the focal distance of the lens 54 caused by thermal expansion and contraction can be corrected automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an optical measuring device, and more particularly to an improvement in an optical measuring device that uses a laser beam to measure the dimensions of an object to be measured.

(Prior Art) Conventionally, a rotating scanning beam (laser beam) is converted into a parallel scanning beam passing between this lens and a condensing lens by a lens, and an object to be measured is placed between the lens and the condensing lens. buy,
There is an optical measuring device (d) that measures the dimensions of the object to be measured based on the time of the 11th part or bright area where the parallel scanning beam is blocked by the object to be measured.

For example, as shown in FIG. The scanning beam 17 is converted into a parallel scanning beam 20 by the lens 18, and the object to be measured 2 placed between the lens 18 and the condensing lens 220 is detected by the parallel scanning beam 20.
4 is scanned at high speed, and the dimensions of the object to be measured 240 in the scanning direction and the Y direction are measured from the length of time of dark or bright areas generated by the object to be measured 24 at that time.

That is, the bright part 8 of the parallel scanning beam 20 is the condenser lens 22.
The signal from the light receiving element 26 is input to the preamplifier 28, where it is amplified and then sent to the segment selection circuit 30. This segment selection circuit 30 is
A voltage V for opening the gate circuit 32 only during the time t during which the object to be measured 24 is scanned from the output voltage of the light receiving element 26.
is generated and output to the gate circuit 32. This gate circuit 32 includes a clock pulse oscillator 3
Since the clock pulse CP is input from 4, the gate circuit inputs the clock pulse P corresponding to the time t corresponding to the scanning direction dimension (for example, outer diameter) of the object to be measured 24 to the counting circuit 36.

The counting circuit 36 counts the clock pulses P and outputs a counting signal to the digital display 38, and the digital display 38 digitally displays the dimension in the scanning direction, that is, the outer diameter of the object 24 to be measured. On the other hand, the polygonal rotating mirror 16
The clock pulse oscillator 34 is controlled by a frequency dividing circuit 40 that divides the frequency of the output of the clock pulse oscillator 34 and a pulse motor 44 that is driven based on the clock pulses whose frequency is divided by this and amplified by a power amplifier 42.
It is rotated in synchronization with the output clock pulse CP to maintain a measurement accuracy of N.

By the way, there is an optical measuring device that uses a laser-emitting semiconductor instead of the laser tube 10.

In this case, the laser light generated from the laser-emitting semiconductor must be converted into a parallel beam by a collimator lens in order to be diffused.

This collimator lens is generally made of a plurality of glass lenses, due to its characteristics and convenience in lens processing.

In response to this, in recent years, attempts have been made to make the collimator lens an integrally molded lens made of synthetic resin, from the viewpoint of downsizing the device and improving productivity in the field.

(Problem to be Solved by the Invention 1) However, the synthetic resin-covered lens described above has a larger tensile coefficient of 491 m than a glass lens, so it expands and contracts in the lens diameter direction due to temperature changes. In doing so, the focal length will vary considerably.

Therefore, the diameter of the laser beam that has passed through the collimator lens is expanded at the rotating mirror surface.

As the diameter of the laser beam becomes larger, a problem arises in that the accuracy of detecting edges of the object to be measured when the laser beam scans the object naturally decreases.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems, and includes a collimator lens made of synthetic resin for converting laser light emitted from a laser-emitting semiconductor into a parallel beam, It is an object of the present invention to provide an optical measuring device that absorbs changes in focal point pressure due to thermal expansion and contraction of a lens and prevents a decrease in measurement r+'i.

[Means for Solving the Problems 1] The present invention includes a laser emitter that irradiates a laser beam onto an object to be measured, and receives the laser beam that has passed through or reflected from the object to be measured and converts it into an electrical signal. and an electronic circuit that processes the electric signal from the photoelectric converter to calculate the dimensions of the object to be measured, etc. The device includes a laser-emitting semiconductor, an integrally molded collimator lens made of synthetic resin for converting the light from the laser-emitting semiconductor into a parallel beam with a predetermined cross-sectional shape, and a collimator lens that supports the collimator lens and that The above object is achieved by comprising a lens holding member formed to be thermally expandable and contractible along the optical axis of the collimator lens in order to correct the changing focus of the collimator lens to a predetermined position of the laser light emitting semiconductor. It is something to be achieved.

Further, the above object is achieved by constructing the lens holding member from a plurality of cylindrical bodies made of materials 13+ having different VA expansion coefficients.

Further, the lens holding member is attached to a first cylindrical body attached to a support base from which the laser emitting semiconductor is taken, and the collimator lens is held coaxially inside the first cylindrical body and the first cylinder. The above object is achieved by comprising a second cylindrical body which is fitted into the cylindrical body so that at least a portion of the second cylindrical body is movable in the axial direction.

Furthermore, the second cylindrical body is formed from a material having a coefficient of linear expansion smaller than that of the first cylindrical body, and is attached so as to be thermally expandable and contractible with respect to the distal end side of the first cylindrical body, and the collimator lens is supported near the end of the second cylindrical body on the side of the laser emitting semiconductor, thereby achieving the above object.

[Function] In the present invention, even when the collimator lens expands and contracts due to temperature changes and its focal length changes, the lens holding member also thermally expands and contracts due to temperature changes, correcting the focal length fluctuation of the collimator lens.

[Example 1 Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, this embodiment uses an optical measuring device as shown in FIG. A collimator lens 54 made of synthetic resin is integrally molded to convert the beam into a parallel beam having a predetermined cross-sectional shape. and a lens holding member 56 that is formed to be thermally expandable and contractible along the optical axis of the collimator lens 54 in order to correct the collimator lens 54 to a predetermined position.

The lens holding member 56 coaxially holds the first cylindrical body 60 attached to the support base 58 from which the laser emitting semiconductor 52 is removed, and 1) the collimator lens 54 inside thereof. At the same time, the first article 60
A second cylindrical body 62 is fitted therein such that at least a portion of the second cylindrical body 62 is movable in the axial direction.

The second cylindrical body 62 is made of aluminum, which is a material with a linear expansion coefficient smaller than that of the first cylindrical body 60, which is made of synthetic fat.
It is attached so that it can be expanded and contracted by heat with the tip side as a reference.

Specifically, the second cylindrical body 62 has a small diameter portion 62A near the end opposite to the support base 58, and has a small diameter portion 62A near the end opposite to the support base 58.
The large diameter portion 62B on the 8th side is fitted into the first cylindrical body 62, and its position is regulated in the axial direction by a nut member 64 that abuts on the stepped portion 62C between the two.

The nut member 64 is screwed onto the tip of the first cylindrical body 60.

Additionally, a compression coil spring 68 is installed between the end of the second cylindrical body 62 on the support base 58 side and the inner circumferential flange 66 of the first centrifugal body 60. The conditioner 62 is biased so that its stepped portion 62C comes into pressure contact with the nut member 64.

The collimator lens 54 includes: 1) U2 second cylindrical body 62;
is supported near the end on the side of the laser emitting semiconductor 52 .

Reference numeral 70 in FIG. 1 indicates an inner peripheral groove formed on the inner periphery of the second cylindrical body 62;
The outer circumferential portion is held within the inner circumferential groove 70 in a diametrically retractable state.

Reference numerals 58A and 60Δ in FIG.
~ indicates a hole.

The first cylindrical body 60 is connected to the optical axis of the loser optical semiconductor 52 by a bolt 74A inserted into the bolt holes 58A, 60A with a margin in the radial direction and a nut 74B screwed thereto. 54, the optical axis alignment can be adjusted.

Here, the length of the first cylindrical body 60, the length of the second cylindrical body 60.
The distance from the stepped portion 62G to the inner circumferential groove 70 in the collimator lens 5 and the material of these materials may vary due to temperature changes.
4 expands and contracts in its radial direction, thereby increasing or decreasing the focal length of the collimator lens 54, the first cylindrical body 60
and the inner circumference f+'l'i due to thermal expansion and contraction of the second cylindrical body 62
The distance #i change from the support base 58 of 70 is preselected to correct the focal length change.

Next, the operation of the above embodiment will be explained.

First, when the collimator lens 54 expands in the diametrical direction due to temperature rise from the reference state shown in FIG. 2(B), and its thickness becomes thinner as shown in FIG. 2(A),
As shown by the solid line in the figure, the focal point 54A of the collimator lens 54 is located a distance S behind the laser emitting semiconductor 52.
It will be shifted by 1.

At this time, the first cylindrical body 60 also expands in its axial direction due to thermal expansion, and the 28th cylindrical body 62 extends in the opposite direction to the first cylindrical body 60 with respect to the step portion 62C.

Here, the first cylindrical body 60 is made of synthetic resin, and the second cylindrical body 62 is made of aluminum, and since the thermal expansion coefficient of the former is larger than that of the latter, as a result, the second cylindrical body 62 is made of synthetic resin. 62, that is, the position of the collimator lens 54 is moved by a distance S2 in a direction further away from the support base 58.

As mentioned in Mi'i, this movement S2 is designed to correct the change in the focal length due to the temperature change of the collimator lens 54, so S z =31, and the change in focal length due to thermal expansion is corrected. The focal point 54A of the collimator lens 54 is corrected to the HpB level of the laser light emitting semiconductor 52, as shown by the two-dot chain line in FIG. 2(A).

Contrary to the above, as shown in FIG. 2(C), the group l
(From the +- state, the collimator lens 54 contracts in its radial direction by Il!2 due to the temperature drop, and the lens ρ radius increases by 51
1 larger, the distance of the focal point 54A to the collimator lens 54 side is $
Even when displaced by 3, the inner circumference is in the opposite direction to I) h! i/r
70 moves by a distance of -ts4 (=83) to correct the focal point 54A to the reference position of the laser light emitting semiconductor 52.

d3 In the above embodiment, the lens holding member 5 G(J
5. The first cylindrical body 60 and the second cylindrical body made of materials with different glandular expansion coefficients.
Although the cylindrical body 62 is formed by /v'''c, the present invention is not limited thereto. Good to have.

Therefore, from only one cylindrical body, 474 lens holding members can be assembled.
It is also possible to do so.

However, as in the above embodiment, the first
The lens holding member 5 is held by the cylindrical body 60 and the second cylindrical body 62.
6 is composed of these first cylindrical body 60 and V second@
By appropriately selecting and combining the materials of the shaped body 62,
There is an advantage that the focal length variation based on the thermal change of the collimator lens 54 can be more accurately controlled.

Moreover, in this case, by keeping the tA quality of the first cylindrical body 60 constant and appropriately selecting the length and material of only the second cylindrical body 62, it is possible to easily correct the focal fluctuation of the collimator lens 54. That's a big deal.

In this case, since only the second cylindrical body 62 is replaced, the central axis of the first cylindrical body 60 and the central axis of the laser-emitting semiconductor 52 are aligned in advance and the second filtration body 62 is replaced. This has the advantage that there is no need to align the optical axis each time.

J3, the lens holding member 56 is made of three or more cylindrical bodies (1
It may be configured to have four components.

Effects of the Invention 1 Since the present invention is configured as described above, even if the collimator lens constituting a part of the laser emitter is synthesized in one piece, the focal length of the collimator lens will change due to thermal expansion and contraction. This has the excellent effect of automatically and mechanically correcting the focal point of the collimator lens to match the reference position of the laser emitting semiconductor.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of an optical measuring device according to the present invention, FIG. 2 is a schematic diagram showing the operation of the same embodiment, and FIG. 3 is a sectional view of an optical measuring device to which the present invention is applied. FIG. 2 is a block diagram showing a general configuration. 50... Laser emitter, 52... Laser emitting semiconductor, 54... Collimator lens, 56... Lens holding member, 58... Support base, 60... First cylindrical body, 62... ...Second cylindrical body.

Claims (4)

[Claims] (1) A laser emitter that irradiates a laser beam onto an object to be measured, a photoelectric converter that receives the laser beam that has passed through or reflected from the object to be measured and converts it into an electrical signal, and electricity from the photoelectric converter. An optical measuring device comprising: an electronic circuit that processes signals to calculate the dimensions, etc. of the object to be measured; An integrally molded collimator lens made of synthetic resin for converting into a parallel beam having a cross-sectional shape, supporting this collimator lens, and correcting the focal point of the collimator lens, which changes due to temperature changes, to a predetermined position of the laser light emitting semiconductor. and a lens holding member formed to be thermally expandable and contractible along the optical axis of the collimator lens. (2) The optical measuring device according to claim 1, wherein the lens holding member is constituted by a plurality of cylindrical bodies made of materials having mutually different coefficients of linear expansion. (3) The lens holding member includes a first cylindrical body attached to a support base to which the laser emitting semiconductor is attached;
A second cylindrical body that coaxially holds the collimator lens inside the second cylindrical body, and at least a portion of the second cylindrical body is fitted in the first cylindrical body so as to be movable in the axial direction. 2. The optical measuring device according to item 2. (4) the second cylindrical body is formed from a material with a coefficient of linear expansion smaller than that of the first cylindrical body, and is attached to be able to expand and contract thermally with respect to the distal end side of the first cylindrical body; The collimator lens is supported near the end of the second cylindrical body on the side of the laser emitting semiconductor.
Optical measuring device as described in section.