JP3063347B2 - Shape measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring device for measuring the shape of an object to be measured using a laser slit light,
In particular, the present invention relates to a shape measuring device capable of receiving reflected light in a certain wavelength range.

[0002]

2. Description of the Related Art Conventionally, a shape measuring apparatus using laser slit light has been used. This shape measuring device
The shape of the reflected light from the measured object is measured by binarizing the reflected light. This shape measurement device is provided with an interference filter that blocks general light that affects the measurement accuracy,
The reflected light is input to the light receiving means via the interference filter. The interference filter is a long-wavelength band transmission filter that transmits only light of a certain wavelength or more, or an interference filter having a sharp characteristic that transmits only a certain wavelength band.

[0003]

However, since the light transmission characteristics of this conventionally used interference filter are very sharp, the wavelength of the laser slit light changes due to a change in temperature or variation in products. In such a case, it is necessary to reselect an interference filter having characteristics suitable for the wavelength. Further, the long wavelength band transmission type filter has a characteristic that all light having a wavelength equal to or more than the wavelength of the light output from the irradiation unit is transmitted, and thus there is a problem that the S / N ratio is reduced. The present invention has been made in order to solve the conventional problems as described above, and even when a slight change occurs in the wavelength of the laser slit light due to various factors, the wavelength change range thereof. It is an object of the present invention to provide a shape measuring device that allows reflected light in the inside to be surely incident.

[0004]

In order to achieve the above object, the present invention provides an object to be measured by irradiating the object with laser slit light from an irradiating unit and receiving the reflected light by a light receiving unit. In the shape measuring device for measuring the shape of the, a plurality of filters each having a different light wavelength transmission region is arranged in series between the light receiving means and the object to be measured, and only a predetermined wavelength region over a width of 150 nm is arranged. The reflected light can be input to the light receiving means.

[0005]

Each of the plurality of filters provided between the light receiving means and the object to be measured has a different light wavelength transmission region. When these filters are stacked in series,
The respective light wavelength transmission regions are superimposed. Therefore, only light having a wavelength within the light wavelength transmission region formed by these filters is input to the light receiving means. If the light wavelength transmission region is set in consideration of the change region of the wavelength of the laser slit light output from the irradiation unit, S / S can be performed regardless of the wavelength change.
Good measurement of the N ratio becomes possible.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an external view of a shape measuring apparatus according to the present invention, and FIG. 2 is a schematic configuration diagram around a CCD camera of the apparatus shown in FIG. FIG. 3 is a diagram showing the light wavelength transmission characteristics of each filter. In the shape measuring apparatus of the present invention, a laser beam irradiating means 1 is provided as shown in FIG. 1, and a laser slit light L as shown in FIG. The reflected light L ′ of the laser slit light L from the device under test 2 is applied to the bandpass filter 4.
Is input to the CCD camera 3 via the. At this time, CCD
The light reaching the camera 3 is light having any wavelength including not only its reflected light L 'but also general light. A band-pass filter 4 is provided to selectively input only the reflected light L 'out of the light. The band-pass filter 4 is not affected by variations in the product generated when the laser irradiating means 1 is manufactured and a change in the light color (wavelength) of the laser slit light due to a change in the temperature, and does not transmit general light. It has. The reflected light L ′ input to the CCD camera 3 is converted into digital data after being photoelectrically converted, and the shape of the measured object is calculated based on the digital data.

FIG. 2 is a configuration diagram around the CCD camera 3 shown in FIG. The CCD camera 3 includes a CCD element 5 and an imaging lens 6. The CCD element 5 converts the input laser slit light into an electric signal corresponding to the light amount, and the imaging lens 6 is a lens that forms an image of the input laser slit light on the CCD element 5. The bandpass filter 4 is attached to the laser slit light input side of the imaging lens 6. In this embodiment, the band pass filter 4 is provided on the front side of the imaging lens 6, but
If the laser slit light can be imaged on the CCD element 5, the pan-pass filter 4 is connected to the imaging lens 6 and C
You may arrange | position between CD elements 5. This bandpass filter 4 is formed by stacking five filters 4a to 4e having different light transmission characteristics. Each of these five filters has characteristics as shown in FIG. The filter 4a has a light transmission characteristic as shown in FIG. That is, the filter 4b has a characteristic of transmitting light having wavelengths of 300 to 700 nm and 900 nm or more, and the filter 4b has a characteristic of 300 to 900 as shown in FIG.
The filter 4c has a characteristic of transmitting light having a wavelength of 1100 nm or more and a wavelength of 1100 nm or more.
It has the property of transmitting light of wavelengths from 0 to 1000 nm and 1200 nm or more. The filter 4d has a characteristic of transmitting light having a wavelength of 400 nm or less and 600 nm or more as shown in FIG.
Has a characteristic of transmitting light having a wavelength of 500 nm or more as shown in FIG. The band-pass filters 4 have the above-described light transmission characteristics.
Since 4 e is in the connected in series, the combined light transmission properties, 550～700N as in FIG (F)
m and a characteristic of transmitting light having a wavelength of 1250 nm or more.

By using a plurality of filters having different transmission characteristics, it is possible to generate an arbitrary combined light transmission characteristic. In the present embodiment, only the light in such a region is transmitted.While permitting wavelength variation due to product variation of the laser slit light and wavelength change due to temperature change, transmission of other light is suppressed as much as possible. This is to improve the S / N ratio at the time of measurement as much as possible.
When the S / N ratio of the measurement is improved, the irradiation intensity of the laser slit light can be reduced.
For this reason, it is very advantageous in safety measures. Further, since the transmission band is set to have a certain width, it is not necessary to replace the filter with an optimum filter according to the product variation of the laser slit light and the temperature change.

[0009]

As described above, according to the present invention, good shape measurement of S / N can be achieved regardless of wavelength variation due to product variation of laser slit light output from the irradiating means and wavelength change due to temperature change. Can be performed.

[Brief description of the drawings]

FIG. 1 is an external view of a shape measuring apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram around a CCD camera constituting the device shown in FIG. 1;

FIG. 3 is a diagram illustrating light wavelength transmission characteristics of each filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Laser irradiation means (irradiation means) 2 ... Measured object 3 ... CCD camera (light receiving means) 4 ... Band pass filter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-249005 (JP, A) “Optical Measurement Handbook”, first edition, Asakura Shoten Co., Ltd., issued July 25, 1981, p. 85-86 (58) Field surveyed (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 102

Claims (1)

(57) [Claims] 1. A shape measuring apparatus which irradiates a laser slit light from an irradiating means to an object to be measured and receives the reflected light by a light receiving means to measure the shape of the object to be measured. A plurality of filters each having a different light wavelength transmission region are arranged in series between the device and the object to be measured, so that reflected light only in a predetermined wavelength region over a width of 150 nm can be input to the light receiving means. Characteristic shape measuring device.