SHAPE MEASURING INSTRUMENT WITH LIGHT SOURCE CONTROL
An optical system of a shape measuring instrument includes a laser diode, a first optical system irradiating an object to be measured with laser beam, a second optical system focusing reflected light from the object to be measured, and a CCD line sensor portion for detecting a laser beam from the second optical system, where the first optical system includes an optical path displacing unit for displacing an optical path for laser beam, the optical path displacing unit includes a glass plate rotating about a rotating axis extending in a direction perpendicular to a displacement plane of the optical path, a rotating unit for the glass plate, and a rotating unit controller, and the rotating unit controller causes a rotation angle of the rotating unit to coincide with a rotation angle of the rotating unit obtained when the maximum value of an amount of light received by the CCD line sensor according to rotation of the rotating unit is measured by the rotating unit controller.
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The present invention relates to a shape measuring instrument utilizing a non-contact sensor.
BACKGROUNDA conventional shape measuring instrument utilizing a non-contact sensor includes a shape measuring device which utilizes a non-contact sensor to measure a shape of a surface of an object and outputs measurement data of the shape, a computer main body which processes the measurement data outputted from the shape measuring device, and a display device which is controlled by the computer main body to display an image of the object.
In the shape measuring device, the position of the surface of the object to be measured is measured by measuring a displacement amount of the image location of returning light on the line sensor 118a of the CCD line sensor portion 118, but when the image location of the returning light is focused at a position deviated from the line sensor 118a (a position in a direction forming an angle of 90° to an extending direction of the line sensor 118a), the amount of light which can be received by the line sensor 118a lowers, which results in impossibility of measurement. The deviation of the image location of returning light is caused by deviation of an optical axis of the optical system of the shape measuring device.
When such optical axis deviation occurs, maintenance for performing position adjustment of the abovementioned respective members configuring the optical system of the shape measuring device or the CCD line sensor portion 118 is required.
However, since the maintenance work must be performed by a skilled Operator or worker precisely, which results in such a problem that much cost and time are required for the maintenance work.
SUMMARYIn view of these circumstances, an object of the present invention is to provide a shape measuring instrument, particularly a three dimensional shape measuring instrument, having a shape measuring device which allows correction of optical axis deviation without conducting maintenance work.
According to an aspect of the present invention, there is provided a shape measuring instrument comprising: a laser diode for emitting laser beam; a first optical system irradiating a surface of an object to be measured with laser beam emitted from the laser diode; a second optical system for focusing laser beam which is reflected from the surface of the object to be measured; and a CCD line sensor portion for detecting an image location of the laser beam from the second optical system, wherein the first optical system has an optical path displacing unit for displacing an optical path of laser beam such that laser beam from the second optical system is properly focused on the CCD line sensor portion; the optical path displacing unit includes a glass plate rotating about a rotating axis extending in a direction perpendicular to a displacement plane of the optical path, a rotating unit for rotating the glass plate, and a rotating unit controller for controlling the rotating unit; and the rotating unit controller measures change of the amount of light received by the CCD line sensor portion according to rotation of the rotating unit and causes a rotation angle of the rotating unit to coincide with a rotation angle of the rotating unit obtained when the maximum value of the amount of light received by the CCD line sensor portion is measured.
It is further preferable in the shape measuring instrument according to the present invention that the rotating unit is driven by a motor, preferably an ultrasonic transducer. Rotation is a general expression and therefore including pivoting movements relative to an axis of rotation.
The shape measuring instrument, particularly the three dimensional shape measuring instrument, according to the present invention described in claim 1 is configured such that the first optical system includes the optical path displacing unit, and change of the amount of light received by the CCD line sensor portion according to rotation of the rotating unit is measured by the rotating unit controller, so that a rotation angle of the rotating unit is caused to coincide with a rotation angle of the rotating unit obtained when the maximum value of the amount of light received by the CCD line sensor portion is measured. Accordingly, since an optical axis deviation of the optical system of the shape measuring device can be corrected, it is unnecessary to conduct maintenance work for performing position adjustment of the CCD line sensor portion conducted conventionally.
The shape measuring instrument according to the present invention is driven by the ultrasonic transducer. Accordingly, a stopping state of the rotating unit can be maintained at a vibration stopping time of the ultrasonic transducer.
An embodiment of the present invention will be explained in detail below with reference to
The shape measuring instrument according to the present embodiment mainly includes a shape measuring device which uses the CCD line sensor portion 12 to measure a shape of a surface of an object to be measured, particularly a three dimensional shape, and output data of the measurement, a computer main body which processes the data of measurement outputted from the shape measuring device, and a display device which displays an image of the object to be measured, particularly a three dimensional image, under control of the computer main body. Incidentally, the computer main body stores a software configuring the rotating unit controller described later therein.
DETAILED DESCRIPTION
The second mirror 5 is provided at one end of a rotating shaft of a swinging motor 6, and it is rotated about Y axis shown in
In the second optical system for focusing laser beam which is reflected from a surface of an object to be measured, the third mirror 7, the fourth mirror 8, the fifth mirror 9, and sixth mirror 11 are provided for changing the direction of the laser beam which is returning light, and the imaging lens portion 10 is disposed so as to concentrate returning light and focus the same on the line sensor 12a of the CCD line sensor portion 12. As described above, the third mirror 7 is rotated about Y axis shown in
When current is fed to the oscillator 27, the oscillator 27b vibrates. Vibration of the oscillator 27 vibrates the vibration shaft 26 so that the sliding piece 25 moves along the vibration shaft 26 according to vibration of the vibration shaft 26. Incidentally, when current feeding to the oscillator 27 is stopped, movement of the sliding piece 25 is stopped, and the vibration shaft 26 is maintained at its stopped position. Control of current feeding to the oscillator 27 is performed by the rotating unit controller described later.
The arm 23 rotates the fulcrum 22 by the protrusions 24 according to movement of the sliding piece 25. The glass plate 21 rotates about the fulcrum portion 22 in an arrow direction shown in
As shown in
Control of rotation of the glass plate 21 of the rotating unit is performed by the rotating unit controller. In the present embodiment, the rotating unit controller is software stored in the computer main body configuring the shape measuring instrument. The computer main body includes two main Operation modes, one thereof being a shape measuring mode performing shape measurement and the other thereof being an optical axis correcting mode. When a user operates the computer main body to select the optical axis correcting mode, the rotating unit controller measures change of an amount of light received by the CCD line sensor portion 12 according to rotation of the rotating unit and causes a rotation angle of the rotating unit to coincide with a rotation angle of the rotating unit obtained when the maximum value of the amount of light received by the CCD line sensor portion 12 is measured.
Operation effect of the present embodiment will be explained below.
In the shape measuring instrument according to the present embodiment, the optical path displacing unit 20 is provided in the first optical system, and when a user operates the computer main body to select the optical axis correcting mode, the rotating unit controller measures the change of an amount of light received by the CCD line sensor portion 12 according to rotation of the rotating unit and causes a rotation angle of the rotating unit to coincide with a rotation angle of the rotating unit obtained when the maximum value of the amount of light received by the CCD line sensor portion 12 is measure. Accordingly, since an optical axis deviation of the optical system 1 of the shape measuring device can be corrected, maintenance work for performing position adjustment of the CCD line sensor portion performed conventionally becomes unnecessary.
Further, in the shape measuring device according to the present embodiment, the rotating unit is driven by the oscillator 27 which is the ultrasonic transducer. Accordingly, the sliding piece comes in close contact with the vibration shaft 26 at a vibration stopping time so that a stopping state can be maintained. Instead of an ultrasonic transducer any other motor or driving device for positioning the glass plate under defined rotational angles can be used.
BRIEF DESCRIPTION OF THE DRAWINGS
- 1: optical system of shape measuring device
- 2, 11: laser diode
- 3: beam expander
- 4: first mirror
- 5: second mirror
- 6: swinging motor
- 7: third mirror
- 8: fourth mirror
- 9: fifth mirror
- 10, 117: imaging lens portion
- 10a, 117a: imaging lens
- 11: sixth mirror
- 12, 118: CCD line sensor portion
- 12a, 118a: line sensor
- 20: optical path displacing means
- 21: glass plate
- 22: fulcrum portion
- 23: arm
- 24: protrusion
- 25: sliding piece
- 26: vibration shaft
- 27: oscillator
- 112: beam expander
- 113: first mirror
- 114: second mirror
- 115: third mirror
- 116: fourth mirror
Claims
1.-5. (canceled)
6. A shape measuring instrument comprising:
- a laser diode for emitting a laser beam;
- a first optical system irradiating a surface of an object to be measured with laser beam emitted from the laser diode;
- a second optical system for focusing the laser beam reflected from the surface of the object to be measured; and
- a line sensor for detecting the laser beam from the second optical system, wherein the first optical system includes: an optical path displacing unit for displacing an optical path of the laser beam such that the laser beam from the second optical system is properly focused on the line sensor, wherein the optical path displacing unit includes: a glass plate rotatable about an axis of rotation wherein rotation causes a parallel displacement of the laser beam at the displacing unit and a displacement of the laser beam in a direction forming an angle of 90° to the line sensor at the line sensor; a rotating unit for rotating the glass plate; and a rotating unit controller for controlling the rotating unit, wherein the rotating unit controller measures an amount of light received by the line sensor corresponding to an angle of rotation of the rotating unit and causes an angle of rotation of the rotating unit to coincide with the angle of rotation of the rotating unit obtained when the maximum value of an amount of light received by the line sensor was measured.
7. The shape measuring instrument according to claim 6, wherein the rotating unit is driven by a motor.
8. The shape measuring instrument according to claim 6, wherein the rotating unit is driven by an ultrasonic transducer.
9. The shape measuring instrument according to claim 6, wherein the line sensor for detecting the laser beam is a CCD line sensor.
10. The shape measuring instrument according to claim 6, wherein the rotating unit comprises:
- a fulcrum portion supporting the glass plate and configuring the axis of rotation;
- an arm fixed to the fulcrum portion; and
- a moving piece for rotating the fulcrum portion, wherein said moving piece is coupled to the arm and driven by a driving unit.
11. The shape measuring instrument according to claim 10, wherein driving unit includes an ultrasonic transducer.
Type: Application
Filed: Jul 29, 2008
Publication Date: Mar 31, 2011
Patent Grant number: 8174682
Applicants: Leica Geosystems AG (Heerbrugg), Hexagon Metrology Kabushiki Kaisha (Sagamihara-shi, Kanagawa-ken)
Inventors: Satoshi SUZUKI (Kita-ku, Hamamatsu-shi, Shizuoka-ken), Katsuhiro SATO (Kita-ku, Hamamatsu-shi, Shizuoka-ken), Yoichi SANO (Kita-ku, Hamamatsu-shi, Shizuoka-ken)
Application Number: 12/738,691
International Classification: G01C 3/08 (20060101);