JP3231968B2 - Height 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 height measuring apparatus for scanning a surface to be measured with, for example, a laser beam and measuring the height of the surface to be measured based on the timing of receiving the reflected light.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram of a height measuring device by laser scanning. A rotating mirror 2 is arranged on the optical path of the laser light output from the laser oscillator 1.

[0003] The rotating mirror 2 scans the surface to be measured 3 with the laser light output from the laser oscillator 1 by rotating in the direction of the arrow (a). On the other hand, on the optical path of each reflected laser beam from the surface 3 to be measured, a photoelectric converter 6 is arranged via a condenser lens 4 and a slit plate 5.

As shown in FIG. 7, the slit plate 5 has a plurality of slits 5a to 5e formed in parallel with each other. The surface of the slit plate 5 is reflected from each of the scanning positions A to E on a flat reference surface. The laser light is arranged to pass through each of the slits 5a to 5e.

[0005] A start pulse generator 7 is arranged at the first scanning position among the scanning positions of the rotating mirror 2. The start pulse generator 7 has a function of receiving a laser beam for starting scanning and transmitting the laser beam to the signal processing circuit 8 as a start pulse signal s indicating the start of scanning of the laser beam.

This signal processing circuit inputs detection signals of the respective reflected laser beams output from the photoelectric converter 6, and receives signals based on the time difference between the detection timing of the reflected laser beams and the input of the start pulse signal s. It has a function of determining the height of the measurement surface 3.

With such a configuration, the laser oscillator 1
When the laser light is output from the laser beam, the laser light is scanned on the surface to be measured 3 in a straight line by the rotation of the rotating mirror 2. At this time, if the laser light is incident on the start pulse generator 7 before the laser light is irradiated on the surface 3 to be measured,
The start pulse generator 7 outputs a high-level start pulse signal s indicating the start of laser scanning to a signal processing circuit 8.
To send to.

When a laser beam is scanned on the surface 3 to be measured,
Reflected laser light is generated from the surface 3 to be measured. Of the reflected laser light, the reflected laser light on each optical path connecting the scanning positions A to E on the reference surface and the slits 5a to 5e of the slit plate 5 correspondingly. The laser light passes through each of the slits 5a to 5e and enters the photoelectric converter 6.

For example, first, the reflected laser light from the scanning position a on the surface 3 to be measured passes through the slit 5a and enters the photoelectric converter 6, and then the reflected laser light from the scanning position b passes through the slit 5b. Then, the reflected laser light from each of the scanning positions c to e is incident on the photoelectric converter 6, and then the respective reflected laser light from each of the slits 5 c to 5 c
5e, and sequentially enter the photoelectric converter 6.

The photoelectric converter 6, as shown in FIG. 8, outputs a detection signal which goes to a high level each time each reflected laser beam from each of the scanning positions a to e is incident. Signal processing circuit 8
Inputs the detection signal from the photoelectric converter 6 and obtains the height of the measured surface 3 based on the time difference between the detection timing of each reflected light and the input time of the start pulse signal s.

That is, the signal processing circuit 8 determines in advance the time difference between the time when the start pulse signal s shown in FIG. 8 is input and the detection signal when each reflected laser beam from each of the scanning positions A to E on the reference plane is received. For example, in the case of a detection signal of the scanning position A, the time difference T is stored.

Therefore, when the signal processing circuit 8 receives the detection signals of the scanning positions a to e of the surface 3 to be measured, the signal processing circuit 8 receives the signals of the start pulse signal s and the detection signals of the scanning positions a to e. The time difference, for example, the time difference T if the device position is a
And the height of the surface 3 to be measured is determined from the difference t = TT−T ′ between the time difference T ′ and the previously stored time difference T.

The time difference t becomes larger when the position of the measured surface 3 is higher than the reference surface, and becomes smaller when the position of the measured surface 3 is lower than the reference surface. As described above, since there is a correlation between the time difference t and the height of the measured surface 3, the height of the measured surface 3 is obtained from this relationship.

However, if the width of the surface 3 to be measured is narrow with respect to the laser scanning position, or if the surface 3 to be measured is shifted laterally, reflected laser light passing through the slits 5a to 5e cannot be obtained.

For example, if the surface to be measured 3 is narrow as shown in FIG. 9 and the surface to be measured 3 does not exist at the scanning position a, the reflected laser beam from the surface to be measured 3 as shown in FIG. The reflected laser light from the scanning position a out of the light cannot be obtained.

In an extreme example, the reflected laser beam may pass through only one of the slits 5a to 5e. For this reason, if the reflected laser beam at the scanning position a cannot be obtained, the height of the surface to be measured 3 is obtained from the time difference between the scanning position A of the reference surface and the scanning position b of the surface 3 to be measured. This makes it impossible to measure the height of the surface 3 to be measured.

[0017]

As described above, when the width of the surface 3 to be measured is narrow with respect to the laser scanning position or when the surface 3 to be measured is laterally displaced, the reflected laser beam is applied to all the slits 5a to 5e. Since the light does not pass, reflected laser light at the scanning position cannot be obtained, and the height measurement of the surface 3 to be measured cannot be performed.

Therefore, the present invention measures the height of the surface to be measured reliably even if the width of the surface to be measured is narrow with respect to the laser scanning position or the reflected light passing through all the slits due to lateral displacement is not obtained. It is an object of the present invention to provide a height measuring device that can be used.

[0019]

According to the first aspect of the present invention, the measuring light is scanned on the surface to be measured, and the reflected light is applied to each of the scanning directions on the reference surface corresponding to each of the reflecting directions. In a height measuring device that measures the height of the surface to be measured based on the time difference between the detection timing of each reflected light that has passed through the slit and the start of scanning of the measurement light, each of the slits is provided with each slit. A height measuring apparatus comprising: filters having different transmission wavelengths; and wavelength control means for variably controlling the wavelength of measurement light to each transmission wavelength of each filter.

According to a second aspect of the present invention, there is provided a height measuring apparatus for variably controlling a laser oscillation wavelength of a laser oscillator for outputting a laser beam to each transmission wavelength of each filter. According to the third aspect, the wavelength control means is a height measuring device that sequentially variably controls the wavelength of the measurement light to each transmission wavelength of each filter in synchronization with each scanning cycle of the measurement light on the surface to be measured. is there.

According to the fourth aspect, the wavelength control means adjusts the wavelength of the measuring light in synchronization with the detection of each reflected light transmitted through each filter from the first detection of the reflected light transmitted through the filter. This is a height measuring device that sequentially variably controls each transmission wavelength of the filter.

[0022]

According to the first aspect, when the measuring light is scanned on the surface to be measured and the reflected light passes through the slits, filters having different transmission wavelengths are provided in the slits, and the wavelength of the measuring light is changed. Is variably controlled to each transmission wavelength of each filter, the measurement light is transmitted only through the slit where the transmission wavelengths of the measurement light and the filter match, so that the surface to be measured is moved with respect to the scanning position of the measurement light. If the reflected light is not obtained when the measurement light of a certain wavelength is scanned because the width is narrow or laterally shifted, the height measurement by scanning at this time is not performed, and the measurement is switched to another wavelength. If the reflected light is obtained when scanning the light, the height of the surface to be measured is measured based on the time difference between the detection timing of the reflected light and the start of the scanning of the measuring light at this time.

According to the present invention, when the laser beam is scanned on the surface to be measured and the reflected laser beam is passed through the slits, filters having different transmission wavelengths are provided in the slits, and the laser oscillation of the laser oscillator is performed. When the wavelength is variably controlled to each of the transmission wavelengths of these filters, the laser light is transmitted only through the slits where the transmission wavelengths of the laser light and the filter match, so that the surface to be measured is moved relative to the scanning position of the laser light. If the width is narrow or misaligned and the reflected laser light is not obtained when scanning a laser beam of a certain wavelength, the height measurement by scanning at this time is not performed, switching to another wavelength and scanning the laser beam If the reflected laser light is obtained at the same time, the height of the surface to be measured is measured based on the time difference between the detection timing of the reflected laser light and the start of the scanning of the laser light at this time. It is.

According to the third aspect, the wavelength of the measuring light is sequentially variably controlled to each transmission wavelength of each filter in synchronization with each scanning cycle of the measuring light on the surface to be measured. Is narrow or laterally displaced with respect to the scanning position of the measuring light, and if the reflected light is not obtained when scanning the wavelength of the measuring light in the first scanning cycle, the height by the scanning at this time is used. No measurement is made. If the reflected light is obtained when the measurement light is scanned by switching to another wavelength in the next scanning cycle, based on the time difference between the start of the scanning of the measurement light and the detection timing of the reflected light in this scanning cycle. Thus, the height of the surface to be measured is measured.

According to the fourth aspect, during one scanning cycle of the measuring light, the surface to be measured is narrow or laterally shifted with respect to the scanning position of the measuring light, and the measuring surface is moved to the first scanning position. If no reflected light is obtained when scanning the light, no height measurement is performed. Subsequently, if the reflected light is obtained by scanning the measuring light, the wavelength of the measuring light is sequentially changed in synchronization with the detection of the reflected light from this time, so that the scanning of the measuring light and the detection of each reflected light are started. The height of the surface to be measured is measured based on the time difference from the timing.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The same parts as those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 is a configuration diagram of a height measuring device by laser scanning.

As shown in FIG. 2, the slit plate 10 has a plurality of slits 10a to 10e formed in parallel with each other.
The reflection laser beams from the scanning positions A to E on the reference plane are arranged so as to pass through the slits 10a to 10e.

The slits 10a to 10e are provided with filters 11a to 11e having different transmission wavelengths. The transmission wavelengths of these filters 11a to 11e are, for example, 600 nm, 630 nm, 660 nm, and 6 nm.
It has 90 nm and 720 nm.

On the other hand, the tunable laser oscillator 12 adjusts the laser oscillation wavelength to the same wavelength as each of the transmission wavelengths of the filters 10a to 10e at 600 nm, 630 nm, 660 nm, and 69.
It has a function of outputting each laser light of 0 nm and 720 nm. Note that the laser oscillator 12 is arranged so that the output laser light is applied to the rotating mirror 2.

An oscillation wavelength control circuit 13 is connected to the laser oscillator 12. This oscillation wavelength control circuit 13
Sets the laser oscillation wavelength fn of the laser oscillator 12 every time the start pulse signal s for each scan of the laser light is input,
The same wavelength f as each transmission wavelength of each of the filters 10a to 10e.
1 = 600 nm, f2 = 630 nm, f3 = 660 n
It has a function of sequentially switching m, f4 = 690 nm, and f5 = 720 nm.

The signal processing circuit 14 inputs a start pulse signal s for each scan of the laser beam, and inputs a detection signal of the reflected laser beam output from the photoelectric converter 6. It has a function of obtaining the height of the measured surface 3 based on the time difference from the time when the pulse signal s is input.

Next, the operation of the above-configured device will be described. When laser light is output from the laser oscillator 1, the laser light is scanned on the surface to be measured 3 by rotation of the rotating mirror 2.

If the laser light is incident on the start pulse generator 7 before the surface to be measured 3 is irradiated with the laser light,
The start pulse generator 7 sends a high-level start pulse signal s indicating the start of laser scanning to the oscillation wavelength control circuit 13 and the signal processing circuit 14.

The oscillation wavelength control circuit 13 switches the laser oscillation wavelength fn of the laser oscillator 12 to f1 = 600 nm in response to the input of the start pulse signal s. This laser oscillator 12 has a laser oscillation wavelength f as shown in FIG.
1 = outputs a laser beam of 600 nm.

When the laser light having a wavelength of 600 nm is scanned on the surface 3 to be measured in this way, reflected laser light is generated from the surface 3 to be measured. Of the reflected laser light, the reflected laser light on each optical path connecting the scanning positions A to E on the reference surface and the slits 10a to 10e correspondingly, that is, the scanning positions a to e on the measured surface 3 The reflected laser light from each of the filters passes through the filters 11a to 11e of the slits 10a to 10e and enters the photoelectric converter 6.

However, if the surface 3 to be measured is narrow or laterally displaced with respect to the scanning range of the laser beam, the reflected laser beam cannot be obtained even if the scanning position a is irradiated with the laser beam. .

Therefore, when a laser beam having a wavelength of 600 nm is scanned on the surface 3 to be measured and the reflected laser beam is not obtained when the laser beam is applied to the scanning position a, the other scanning positions b to e, these scanning positions b to
Since the transmission wavelength of each of the filters 11b to 11e corresponding to e is different from the wavelength of 600 nm, the reflected laser light does not pass through the filters 11b to 11e and does not enter the photoelectric converter 6.

As a result, during the first scanning of the laser beam, the photoelectric converter 6 does not output a detection signal that goes high when the reflected laser beam is received as shown in FIG. Subsequently, scanning of the laser light in the second cycle is performed, and when this laser light enters the start pulse generator 7, the start pulse generator 7 outputs a high-level start pulse signal s indicating the start of laser light scanning. Is sent to the oscillation wavelength control circuit 13 and the signal processing circuit 14.

Here, the oscillation wavelength control circuit 13 switches the laser oscillation wavelength fn of the laser oscillator 12 to f2 = 630 nm by inputting the start pulse signal s, so that the laser oscillator 12 has the laser oscillation wavelength f2 = 630.
Outputs a laser beam of nm.

When the laser light having a wavelength of 600 nm is scanned on the surface 3 to be measured and reaches a scanning position b on the surface 3 to be measured,
The reflected laser light is transmitted through a filter 1 having a transmission wavelength of 630 nm.
The light passes through 1b and enters the photoelectric converter 6.

It should be noted that even if the laser beam is scanned at the subsequent scanning positions c to e, the transmission wavelength of each of the filters 11c to 11e corresponding to these scanning positions c to e is different from the wavelength of 630 nm. Are the filters 11c ~
The light does not pass through the photoelectric converter 6 without passing through 11e.

The photoelectric converter 6 receives the reflected laser beam and outputs a detection signal which becomes high level at this time. Here, the signal processing circuit 14 determines in advance the start pulse signal s
, And the time difference between the detection signal when each reflected laser beam from each of the scanning positions A to E on the reference plane is received, for example, the time difference T for the detection signal at the scanning position A.

Therefore, the signal processing circuit 14 controls the surface 3 to be measured.
Is input, the respective time differences Tb between the input of the start pulse signal s and the detection signal of the scanning position b are obtained, and the difference t = Tb between this time difference Tb and the previously stored time difference T = The height of the measured surface 3 is determined from T-Tb.

That is, the time difference t becomes larger when the position of the measured surface 3 is higher than the reference surface as described above, and becomes smaller when the position of the measured surface 3 is lower than the reference surface.
As described above, since there is a correlation between the time difference t and the height of the measured surface 3, the height of the measured surface 3 is obtained from this relationship.

Thereafter, in each laser beam scanning in the third to fifth periods, when these laser beams enter the start pulse generator 7, each high-level start pulse signal s indicating the start of the laser scanning is controlled by the oscillation wavelength control. The signal is sent to the circuit 13 and the signal processing circuit 14.

As a result, the oscillation wavelength control circuit 13
The laser oscillation wavelength fn of the laser oscillator 12 is changed to f by the input of each start pulse signal s of the laser beam scanning of the fifth to fifth cycles.
3 = 660 nm, f4 = 690 nm, f5 = 720 nm
Switch sequentially.

When the laser light having these wavelengths is scanned on the surface to be measured 3 in each laser light scanning in the third to fifth cycles, the laser light having a wavelength of 660 nm reaches the scanning position c on the surface to be measured 3. The reflected laser light is transmitted through the filter 11c having a transmission wavelength of 660 nm and is incident on the photoelectric converter 6. Similarly, when the laser light having a wavelength of 690 nm reaches the scanning position d, the reflected laser light is converted into a filter 11d having a transmission wavelength of 690 nm. And the laser beam having a wavelength of 720 nm reaches the scanning position e, and the reflected laser beam passes through the filter 11e having a transmission wavelength of 720 nm and enters the photoelectric converter 6.

Therefore, the signal processing circuit 14 controls the surface to be measured 3
When the detection signals of the respective scanning positions c to d are input, when the respective start pulse signals s are input for each scanning period, and when the scanning positions c to d are input.
The respective time differences Tc to Te with respect to the detection signal d are obtained, and the height of the measured surface 3 is obtained from the difference between the time differences Tc to Te and the previously stored time difference T.

As described above, according to the first embodiment, the width of the surface 3 to be measured is narrow or laterally shifted with respect to the scanning range of the laser light, and reflected light is obtained when the laser light of a certain wavelength is scanned. Even if it is not possible, the height is not measured by scanning at this time, and if the reflected laser light is obtained when the laser light is scanned by switching to another wavelength, the detection timing of the reflected laser light at this time and the laser light The height of the measured surface 3 can be measured based on the time difference from the start of scanning.

In this case, the height of the surface 3 to be measured can be measured even if the reflected laser light is not obtained in the first laser scanning, for example, the first laser scanning, but the present invention is not limited to this.
The surface to be measured 3 is determined based on the time difference between the detection timing of the reflected laser beam and the start of scanning of the laser beam for each laser scanning cycle.
Is measured, the height of the measured surface 3 can be measured even if the measured surface 3 is broken in the middle.

In the first embodiment, the laser scanning positions a to e are set to five points.
The height position may be measured at the zero point. In this case, the filter may be prepared for 20 wavelengths.

Next, a second embodiment of the present invention will be described. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 4 is a configuration diagram of a height measuring device by laser scanning.

The oscillation wavelength control circuit 20 sets the laser oscillation wavelength fn of the laser oscillator 12 to f1 = 600 nm and f1 every time the start pulse signal s for each scanning of the laser beam is input.
2 = 630 nm, f3 = 660 nm, f4 = 690 n
It has a function of sequentially switching m and f5 to 720 nm.

When the oscillation wavelength control circuit 20 first detects the reflected laser light transmitted through each of the filters 11a to 11e, it synchronizes with the detection of each reflected laser light transmitted through each of the filters 11a to 11e. Laser oscillator 1
2 has a function of sequentially variably controlling the laser oscillation wavelength to each transmission wavelength of each of the filters 11a to 11e.

The signal processing circuit 21 receives the start pulse signal s, and receives a high-level detection signal of each reflected laser beam output from the photoelectric converter 6 during one scanning of the laser beam. It has a function of obtaining the height of the measured surface 3 based on the time difference between each detection timing of the laser light and the time when the start pulse signal s is input.

Next, the operation of the device configured as described above will be described. When a laser beam is output from the laser oscillator 1 and its start pulse signal s is generated, the laser oscillator 12 generates a laser oscillation wavelength f1 = 6 as shown in FIG.
A laser beam of 00 nm is output.

When the laser light having a wavelength of 600 nm is scanned on the surface 3 to be measured, reflected laser light is generated from the surface 3 to be measured. However, the width of the surface 3 to be measured is narrow or laterally shifted with respect to the laser scanning range. In this case, the reflected laser light cannot be obtained at the scanning position a as described above.

Therefore, during the first laser beam scanning, the photoelectric converter 6 does not output a detection signal which becomes high when the reflected laser beam is received as shown in FIG. Subsequently, scanning of the laser beam in the second cycle is performed, and when the start pulse signal s is generated, the laser oscillator 12
Is switched to f2 = 630 nm.

When the laser beam having the wavelength of 630 nm is scanned on the surface 3 to be measured and reaches the scanning position b on the surface 3 to be measured,
The reflected laser light is transmitted through a filter 1 having a transmission wavelength of 630 nm.
The light passes through 1b and enters the photoelectric converter 6.

The photoelectric converter 6 receives the reflected laser beam and outputs a high-level detection signal at this time. When the high-level detection signal is output, the oscillation wavelength control circuit 20 variably controls the laser oscillation wavelength of the laser oscillator 12 to the transmission wavelength of 660 nm of the next filter 11c when the detection signal is input.

When the laser light having the wavelength of 660 nm is scanned on the surface 3 to be measured and reaches the scanning position c on the surface 3 to be measured,
The reflected laser light is transmitted through a filter 1 having a transmission wavelength of 660 nm.
The light passes through 1 c and enters the photoelectric converter 6.

Then, again, the photoelectric converter 6 receives the reflected laser light and outputs a detection signal which becomes high level at this time, so that the oscillation wavelength control circuit 20 sets the laser oscillator 12 when the detection signal is input. Is variably controlled to a transmission wavelength of 690 nm of the next filter 11d.

Thereafter, as described above, when the laser beam reaches each of the scanning positions d and e on the surface 3 to be measured, the reflected laser beam is transmitted to each of the filters 11 having transmission wavelengths of 690 nm and 720 nm.
Since the laser beam passes through d and 11e and enters the photoelectric converter 6, the laser oscillation wavelength of the laser oscillator 12 is variably controlled to 690 nm and 720 nm each time these reflected laser beams are generated.

When the signal processing circuit 21 receives the detection signal of the scanning position b of the surface 3 to be measured as described above, the signal processing circuit 21 detects the input of the start pulse signal s in the second cycle and the detection of the scanning position b as shown in FIG. Each time difference Tb from the signal is obtained, and this time difference Tb is calculated.
The height of the surface to be measured 3 is determined from the difference t = T−Tb between b and the previously stored time difference T.

Subsequently, when the signal processing circuit 21 inputs a detection signal which becomes high level corresponding to each of the scanning positions c to e of the surface 3 to be measured as described above, the input of the start pulse signal s of the second cycle is performed. The respective time differences Tc to Te between the time and the detection signals of the respective scanning positions c to e are obtained, and the height of the measured surface 3 is obtained from the difference between the time differences Tc to Te and the previously stored time difference T.

As described above, according to the second embodiment, the laser oscillation wavelength is adjusted in synchronization with the detection of each reflected laser beam transmitted through each of the filters 11a to 11e.
e, the height of the surface to be measured 3 can be obtained within one cycle of laser scanning for detecting the reflected laser light at first, and the height of the surface to be measured 3 can be measured at high speed. Can be For example, even if there are 20 points for height measurement, the height of the surface 3 to be measured can be measured at high speed without performing laser scanning 20 times.

The present invention is not limited to the above embodiments, but may be modified as follows. For example, when the amount of lateral shaking of the surface to be measured 3 is small or changes gradually with time even if it is large, scanning is performed with a laser beam having a wavelength that matches the transmission wavelength 600 nm of the slit 10a corresponding to the scanning position a. Instead, the laser beam may be scanned with a laser beam having a wavelength coincident with the transmission wavelength 630 nm of the slit 11b corresponding to the scanning position b, so as to eliminate laser scanning dead time.

The slit 10a through which the reflected laser light is transmitted first depends on the amount of roll of the surface 3 to be measured and its roll frequency.
The ratio of oscillating laser light at a wavelength that matches the transmission wavelength of 600 nm and the ratio of oscillating laser light at a wavelength that matches the transmission wavelength of the first slit of the laser light obtained by the previous laser scanning are calculated. If laser scanning is performed from a laser beam having a large laser oscillation wavelength,
In addition, the height measurement of the surface to be measured 3 can be speeded up. Further, laser scanning is not performed at a wavelength coincident with the transmission wavelength 600 nm of the slit 10a, and one of the leading positions of the transmission portion of the slit obtained by the previous laser scanning is performed. If the laser scanning is performed at the laser oscillation wavelength corresponding to the preceding portion, the speed of the height measurement of the surface 3 to be measured can be increased without wasting the laser scanning.
The measuring light is not limited to the laser oscillator, but may be any light source that can output light having different wavelengths.

[0069]

As described above in detail, according to the present invention, even if the width of the surface to be measured is narrow with respect to the laser scanning position, or if the reflected light passing through all the slits is not obtained due to lateral displacement. And a height measuring device capable of measuring the height of the surface to be measured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a height measuring apparatus by laser scanning according to the present invention.

FIG. 2 is a configuration diagram of a slit plate provided with filters having different transmission wavelengths.

FIG. 3 is a timing chart of switching a laser oscillation wavelength in height measurement.

FIG. 4 is a configuration diagram showing a second embodiment of the height measuring apparatus by laser scanning according to the present invention.

FIG. 5 is a timing chart of switching a laser oscillation wavelength in height measurement.

FIG. 6 is a configuration diagram of a conventional device.

FIG. 7 is a configuration diagram of a slit plate.

FIG. 8 is a view showing the operation of height measurement.

FIG. 9 is a diagram showing a case where the width of a surface to be measured is narrow or laterally shifted with respect to a laser scanning position.

FIG. 10 is a view showing the operation of height measurement when the width of the surface to be measured is narrow or laterally shifted with respect to the laser scanning position.

[Explanation of symbols]

2 ... rotating mirror, 3 ... measured surface, 6 ... photoelectric converter, 7 ...
Start pulse generator, 10 ... Slit plate, 10a-1
0e: slit, 11a to 11e: filter, 12: laser oscillator, 13, 20: oscillation wavelength control circuit, 14, 2
1 ... Signal processing circuit.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masamitsu Nishikawa 1-1-1, Shibaura, Minato-ku, Tokyo Inside the Toshiba head office (72) Inventor Masato Nozawa 1 Toshiba-cho, Fuchu-shi, Tokyo Higashi Corporation In the Shiba Fuchu Plant (72) Inventor Yoshitomi Sameda 1 Toshiba-cho, Fuchu-shi, Tokyo Investigator in the Toshiba Fuchu Plant Inc. Kenichi Kamiya (56) References JP-A-6-207821 (JP, A) JP JP-A-3-180710 (JP, A) JP-A-61-11684 (JP, A) JP-A-6-147869 (JP, A) JP-A-3-180710 (JP, A) JP-A-6-313825 (JP) JP-A-5-332741 (JP, A) JP-A-60-134105 (JP, U) JP-A-1-117787 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB G01S 7/48-7/50 G01S 17/00-17/95 G01B 11/00-11/30

Claims (4)

(57) [Claims] 1. A measuring light is scanned on a surface to be measured, and the reflected light is passed through slits provided corresponding to respective reflection directions at respective scanning positions on the reference surface. In a height measurement device that measures the height of the surface to be measured based on a time difference between a light detection timing and a start of scanning of the measurement light, each filter having a different transmission wavelength provided in each slit, And a wavelength control means for variably controlling the wavelength of the measurement light to each transmission wavelength of each of the filters. 2. The height measuring apparatus according to claim 1, wherein a laser oscillation wavelength of a laser oscillator that outputs laser light is variably controlled to each transmission wavelength of each filter. 3. The wavelength control means sequentially variably controls the wavelength of the measurement light to each transmission wavelength of each filter in synchronization with each scanning cycle of the measurement light on the surface to be measured. Item 1. A height measuring device according to Item 1. 4. The wavelength control means, when detecting reflected light transmitted through the filters first, synchronizes the wavelength of the measuring light with each transmitted light of each filter in synchronization with detection of each reflected light transmitted through each filter. 2. The height measuring device according to claim 1, wherein the height is sequentially variably controlled.