JPH052162B2 - - Google Patents

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 measures the dimensions of an object to be measured using parallel scanning beams.

[Prior Art] Conventionally, a rotating scanning beam (laser beam) formed by a rotating plane mirror or a polygon mirror, or a fan-shaped rotating scanning beam modified by a tuning fork deflector, is transferred between the collimating lens and the condensing lens using a collimator lens. The object to be measured is placed between the collimator lens and the condensing lens, and the length of the dark or bright area that occurs when the parallel scanning beam is blocked by the object to be measured. There was an optical measuring device for measuring the dimensions of objects to be measured. For example, as shown in FIGS. 5 and 6,
A laser beam 12 is oscillated from a laser tube 10 toward a fixed mirror 14, and the laser beam 12 reflected by the fixed mirror 14 is converted into a rotating scanning beam 17 by a polygonal rotating mirror 16. It is converted into a parallel scanning beam 20 by the collimator lens 18, and the object to be measured 24 placed between the collimator lens 18 and the condensing lens 22 is scanned at high speed with this parallel scanning beam 20.
At that time, the scanning direction of the measured object 24 (Y
Direction) dimensions are measured. That is, the brightness and darkness of the parallel scanning beam 20 is detected as a change in the output voltage of the light receiving element 26 located at the focal position of the condensing lens 22, and the signal from the light receiving element 26 is input to the preamplifier 28, where it is After being amplified, it is sent to the segment selection circuit 30. The segment selection circuit 30 generates a voltage V from the output voltage of the light receiving element 26 to open the gate circuit 32 only during the time t during which the object to be measured 24 is being scanned, and outputs it to the gauge circuit 32. has been done. Since the clock pulse CP is inputted to this gate circuit 32 from the clock pulse oscillator 34, the clock pulse P corresponding to the time t corresponding to the scanning direction dimension (for example, the outer diameter) of the object to be measured 24 is output from the gate circuit to the counting circuit. 36. Counting circuit 3
6 counts the clock pulses P and outputs a count signal to the digital display 38, which 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 is connected to the clock pulse oscillator 3.
The output of the clock pulse oscillator 34 is driven by a pulse motor 44 driven by a square wave amplified through a power amplifier 42 from a frequency divider 40 which divides the frequency of four outputs to generate a square wave of about 400 to 800 Hz. It is rotated in synchronization with the clock pulse CP to maintain measurement accuracy. This type of high-speed scanning optical measuring device
It is becoming widely used because it can measure the length, thickness, etc. of moving objects and high-temperature objects with high precision in a non-contact manner. At the same time, the range of objects to be measured has expanded, and what used to be relatively small objects to be measured has come to be used for large objects. On the other hand, it is desirable for the measuring device to be as small as possible due to requirements such as installation space and portability.

[Problems to be solved by the invention]

However, in the conventional optical measuring device as shown in FIGS. 5 and 6, the light receiving section 39 including the condenser lens 22 and the light receiving element 26
Since the light receiving element 26 is located at the focal point of the condensing lens 22, when the effective diameters of the collimator lens 18 and the condensing lens 22 are increased in order to expand the measurement range, the focal length of the condensing lens 22 naturally also increases. It must be increased in proportion to the effective diameter. Here, if the focal length of the condensing lens 22 is shortened, aberrations will increase and measurement errors will occur. Therefore, in the past, when the measurement range was expanded, the distance in the optical axis direction of the light receiving section 40, that is, the distance between the condenser lens 22 and the light receiving element 26 had to be increased, which increased the size of the device. There was a problem with this. On the other hand, it is conceivable to provide a reflecting mirror in the middle of the optical path to make the optical path length substantially longer than the device dimensions. In this case, it is necessary to delicately adjust the reflection angle and tilt angle of the reflector to prevent deviations in the optical axis direction due to installation errors. As such a fine adjustment device, for example,
There is a device for adjusting the fixing position of a galvano mirror disclosed in Japanese Patent No. 60-98119. In the former case, the support member of the reflector is vertically positioned using a support pin to adjust the tilting angle, and the reflection angle is also adjusted by rotating the support member horizontally around the support pin. Therefore, even if you try to fine-tune only one of the reflection angles, the adjustment will always have a slight effect on the other, making it difficult to make adjustments for devices that require high precision. There is. This invention was made in view of the above-mentioned conventional problems, and it is possible to increase the focal length of the condensing lens without increasing the size of the light receiving part, and also to increase the optical path length. It is an object of the present invention to provide an optical measuring device that allows the reflection angle and deflection angle of a reflecting mirror to be adjusted individually and without being influenced by each other, and therefore very delicately and with high precision. shall be.

[Means to solve the problem]

The present invention includes a beam conversion means for reflecting an incident beam from a beam generator into a rotating scanning beam;
A parallel scanning beam generator including a collimator lens that converts the rotating scanning beam into a parallel scanning beam;
a light-receiving device including a condenser lens that condenses the parallel scanning beam that has passed through the object to be measured, and a light-receiving element that is disposed at a beam condensing position by the condenser lens and detects brightness or darkness of the condensed scanning beam; , has
A part of the parallel scanning beam is blocked by the object to be measured placed between the parallel scanning beam generator and the light receiving device, and the length of time of a dark or bright area is detected, and the object to be measured is detected. In an optical measuring device configured to determine a dimension in a scanning direction, a reflecting means including at least one reflective mirror for reflecting the scanning beam is disposed on the optical path of the scanning beam between the condenser lens and the light receiving element. The reflecting means includes a mounting base having a substantially L-shaped cross section that supports the reflecting mirror;
A reflection angle adjustment mechanism for rotating and fixing the base of the L-shape along the substrate and around an axis parallel to the scanning direction of the parallel scanning beam; a tilting angle adjustment mechanism for swinging and fixing the reflecting mirror in a plane; a rotation center axis that is rotatably supported around an axis parallel to the scanning direction; and a rotation center axis that is supported by the substrate so as to be rotatable about the center axis that is parallel to the rotation center axis, and is eccentric with respect to the center axis. an eccentric shaft having an eccentric portion; the eccentric shaft is formed at the bottom of the mount and is slidably engaged with the eccentric portion of the eccentric shaft; It has a long hole that allows rotation, and a clamp that can fix the bottom of the mounting base to the substrate at any rotational position around the rotation center axis, and the tilt angle adjustment mechanism has a base end. , a cantilever support piece fixed to a rising side of the mounting base, having a thin wall part near the base end, and supporting the reflecting mirror on the free end side of the thin wall part; and the cantilever support piece. The above object is achieved by including an adjustment screw that engages with the free end of and adjusts the distance between the rising side and the free end.

[Effect]

In this invention, a reflecting mirror is arranged on the optical path between the condensing lens and the light receiving element, thereby
Since the optical path length between the condensing lens and the light receiving element is made larger than the mechanical distance between the condensing lens and the light receiving element, the focal length of the condensing lens can be increased without increasing the device volume of the light receiving part. I can do it. Further, the reflection angle and tilt angle of the reflecting mirror can be easily and delicately adjusted without adjusting play or using complicated adjustment work or adjustment mechanism. Further, at this time, the reflection angle and the tilting angle can be adjusted subtly and accurately independently of each other, thus making the adjustment work easier.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. Here, in this embodiment, parts that are the same as or equivalent to those of the conventional optical measuring device shown in FIGS. 5 and 6 will be explained by giving the same reference numerals as in FIGS. 5 and 6. It shall be omitted. This embodiment, as shown in FIGS. 1 and 2, reflects an incident beam 12 from a laser tube 10, which is a beam inventor as shown in FIG. Square rotating mirror 1
6. The rotating scanning beam 17 is converted into a parallel scanning beam 20.
a parallel scanning beam generator 41 including a collimator lens 18, and a condenser lens 2 for condensing the parallel scanning beam 20 that has passed through the object to be measured 24.
2. A light receiving device 43 including a light receiving element 26 disposed at the beam focusing position by the focusing lens 22 and detecting the brightness of the focused scanning beam;
A part of the parallel scanning beam 20 is blocked by the object to be measured 24 placed between the parallel scanning beam generator and the light receiving device 43, and the length of time of a dark or bright area is detected and the object to be measured is detected. In an optical measuring device configured to determine the scanning direction (Y direction) dimension of an object 24, the condenser lens 22 and the light receiving element 26
A reflecting mirror 45 for reflecting the scanning beam is provided on the optical path of the scanning beam between the scanning beam and the scanning beam. Here, the light receiving element 26 is arranged between the reflecting mirror 45 and the condensing lens 22 at a position offset from the scanning plane of the parallel scanning beam 20, as shown in FIG. This reflecting mirror 45 is a plane mirror, and is attached to a mounting base 46 having a substantially L-shaped cross section as shown in FIGS. 3 and 4 via a swing angle adjustment mechanism 48. The mounting base 46 is rotatable around an axis parallel to the scanning direction of the parallel scanning beam 20 and fixed by a reflection angle adjustment mechanism 50. Further, the tilt angle adjustment mechanism 48 is configured to swing the reflecting mirror 45 in a plane parallel to the scanning direction of the parallel scanning beam 20 and to fix it. More specifically, the reflection angle adjustment mechanism 50 rotates the L-shaped bottom of the mounting base 46 to the bottom (substrate) 51A of the housing 51 around an axis parallel to the scanning direction of the parallel scanning beam 20. a rotational center shaft 52 that can be supported; an eccentric shaft 54 that is rotatably supported by the bottom portion 51A about a center axis 54A parallel to the rotational center axis and provided with an eccentric portion 54B; and the mounting base 46. an elongated hole 56 that is formed in a shape and slidably engages with the eccentric portion 54B of the eccentric shaft 54, and allows rotation of the mounting base 46 about the rotation center axis 52 in the engaged state; A clamp 58 is provided which can fix the mounting base 46 to the bottom portion 51A at any rotational position about the rotation center axis 52. Further, the tilt angle adjustment mechanism 48 is fixed at the base end (lower end) to the L-shaped rising portion 46A of the mounting base 46 with a bolt 59, and includes a thin wall portion 60A near the base end. A cantilever support plate 60 supporting the reflecting mirror 45 on the free end side is engaged with the free end of the cantilever support plate 60 to adjust the distance between the mounting base 46 and the free end. The adjustment screw 62 is configured to include an adjustment screw 62. Reference numeral 64 in the figure indicates a light-receiving element mounting base for mounting the light-receiving element 26. This light-receiving element mounting base 64 is fixed to the bottom portion 51A of the housing 51 of the light-receiving device 43 with bolts 66. In this embodiment, the optical path length between the light receiving element 26 and the condensing lens 22 is made approximately twice the mechanical distance between the two by the reflecting mirror 45. Therefore, the condenser lens 22 in the light receiving device 43
The dimension of the side opposite to the collimator lens 18 is about half that of the conventional one, assuming that the focal length of the condenser lens 22 is the same. In this embodiment, the angle of the reflecting mirror 45 around the axis parallel to the scanning direction of the parallel scanning beam 20;
That is, the reflection angle adjustment mechanism 50 adjusts the reflection angle.
This is carried out by rotating the eccentric shaft 54 in , pivoting the mount 46 around the rotation center axis 52, and fixing the mount 46 at an appropriate position with a clamp 58. At this time, since the eccentric portion 54B of the eccentric shaft 54 is slidably engaged with the elongated hole 56 formed in the mounting base 46, rattling occurs no matter which direction the eccentric shaft 54 is rotated. Therefore, the reflection angle can be adjusted delicately and reliably. Further, the tilt angle θ of the reflecting mirror 45, that is, the vertical reflection position in the drawing with respect to the light receiving element 26 is adjusted by appropriately rotating the adjustment screw 62 in the tilt angle adjustment mechanism 48. When the adjusting screw 62 is rotated appropriately, the cantilever support plate 60 supporting the reflector 45 moves to its base end (lower end).
Since the cantilever support plate 60 is fixed to the mounting base 46 and has a thin section 60A consisting of a notch formed near the lower end thereof, the cantilever support plate 60 can be elastically bent around the thin section 60A. Therefore, by rotating the adjustment screw 62 to adjust the distance between the free end of the cantilever support plate 60 and the mounting base 46, the tilting angle θ of the reflecting mirror 45 can be adjusted. At this time, as described above, the cantilever support plate 60 elastically bends around the thin wall portion 60A, so that the adjustment screw 62 does not buckle, and therefore no backlash occurs when adjusting the tilting angle. ,
The tilt angle can be adjusted delicately and accurately. In this embodiment, the tilt angle and reflection angle of the reflecting mirror 45 can be easily and reliably adjusted by the tilt angle adjustment mechanism 48 and the reflection angle adjustment mechanism 50, which have simple configurations. Further, since the tilt angle and reflection angle of the reflecting mirror 45 can be adjusted separately and independently by the tilt angle adjustment mechanism 48 and the reflection angle adjustment mechanism 50, adjusting one will adjust the other. The adjustment can be made delicately and accurately, and in a short working time, without causing any misalignment. In the above embodiment, the reflecting mirror 45 is a plane mirror, but it may be a convex mirror or a concave mirror. Further, although there is only one reflecting mirror 45 in the above embodiment, there may be a plurality of reflecting mirrors. In this case, assuming that the focal length of the condenser lens 22 is the same, the dimension of the light receiving device 43 in the parallel scanning beam traveling direction can be further reduced. Further, in the above embodiment, a laser beam is converted into a rotating scanning beam using a polygonal rotating mirror called a polygon mirror, but the present invention converts a laser beam into a rotating scanning beam using, for example, a rotating plane mirror. The same applies to those that convert the laser beam into a fan-shaped scanning beam using a tuning fork deflector.

【Effect of the invention】

Since the present invention is configured as described above, the focal length of the condensing lens can be increased without increasing the dimensions of the light receiving device, and therefore the measurement target range can be expanded without increasing the device volume. It has the excellent effect of being able to Furthermore, since the reflection angle adjustment and tilt angle adjustment of the reflector to increase the focal length can be performed independently of each other, even adjustments that require extremely delicate precision can be performed.
It can be done easily.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged sectional view showing an embodiment of the optical measuring device according to the present invention, FIG. 2 is a plan sectional view showing a light receiving device of the same embodiment, and FIG. 3 is a reflection angle adjustment of the same embodiment. A plan view showing the mechanism, FIG. 4 is a front view showing the tilt angle adjustment mechanism in the same embodiment, FIG. 5 is a block diagram showing conventional optical measurement, and FIG. 6 is a parallel view of the conventional optical measuring device. FIG. 2 is a cross-sectional view showing a scanning beam generator and a light receiving device. 10... Laser tube (beam generator), 12...
Laser beam, 16...Polygonal rotating mirror, 17
... Rotating scanning beam, 18 ... Collimator lens, 20 ... Parallel scanning beam, 24 ... Measured object, 26 ... Light receiving element, 43 ... Light receiving device, 45
...Reflector, 46... Mounting base, 48... Tilt angle adjustment mechanism, 50... Reflection angle adjustment mechanism, 51...
...Bottom (substrate), 52...Rotation center axis, 54...
Eccentric shaft, 54A... Central axis, 54B... Eccentric part,
56...Elongated hole, 58...Clamp, 60...Cantilever support plate, 60A...Thin wall portion, 62...Adjustment screw.

Claims (1)

[Claims] 1. A parallel scanning beam generator including a beam conversion means for reflecting an incident beam from a beam generator into a rotational scanning beam, a collimator lens for converting the rotational scanning beam into a parallel scanning beam, and a light receiving device including a condensing lens that condenses the parallel scanning beam, and a light receiving element that is disposed at a beam condensing position by the condensing lens and detects the brightness or darkness of the condensed scanning beam; The scanning direction of the object is determined by detecting the length of the dark or bright portion that occurs when a part of the parallel scanning beam is blocked by the object placed between the scanning beam generator and the light receiving device. In the optical measuring device for determining dimensions, a reflecting means including at least one reflecting mirror for reflecting the scanning beam is disposed on the optical path of the scanning beam between the condenser lens and the light receiving element. The reflecting means includes a mounting base having a substantially L-shaped cross section that supports the reflecting mirror, and a base of the L-shape of the mounting base along the substrate, and
a reflection angle adjustment mechanism that rotates the reflecting mirror around an axis parallel to the scanning direction of the parallel scanning beam and fixes it; and a tilt angle that swings the reflecting mirror in a plane parallel to the scanning direction and fixes it. an adjustment mechanism;
The reflection angle adjustment mechanism has a rotation center shaft that supports the base of the mounting base rotatably around an axis parallel to the scanning direction of the parallel scanning beam, and an eccentric shaft rotatably supported by the substrate about a central axis parallel to the axis and having an eccentric portion eccentric to the central axis; and an eccentric shaft formed at the bottom of the mount;
an elongated hole that slidably engages with the eccentric portion of the eccentric shaft and allows rotation of the mount around the rotation center axis in the engaged state; a clamp that can be fixed to the substrate at any rotational position, and the swing angle adjustment mechanism is fixed to the rising side of the mounting base at the base end, and has a thin wall portion near the base end. a cantilever support plate supporting the reflecting mirror on the free end side of the thin portion; and engaging with the free end of the cantilever support plate;
An optical measuring device comprising: an adjustment screw for adjusting the distance between the rising side and the free end.