阅读说明：本技术 光距离测定装置 (Optical distance measuring device ) 是由 山内隆典 后藤广树 吉田刚 斧原圣史 铃木巨生 于 2019-04-05 设计创作，主要内容包括：光距离测定装置(100、100a)具备：分支部(103),其对激光进行分支,作为测定光及参照光输出；测定光分支部(104),其对测定光进行分支,作为第1测定光及第2测定光输出；参照光分支部(105),其对参照光进行分支,作为第1参照光及第2参照光输出；第1光学系统(131),其具有第1瑞利长度,用于向对象物(20)照射第1测定光；第2光学系统(132),其具有与第1瑞利长度不同的第2瑞利长度,用于向对象物20照射第2测定光；第1接收部(141),其接受第1参照光、和第1测定光在对象物20反射后的光即第1反射光,输出表示第1参照光和第1反射光的第1接收信号；以及第2接收部(142),其接受第2参照光、和第2测定光在对象物20反射后的光即第2反射光,输出表示第2参照光和第2反射光的第2接收信号。(An optical distance measuring device (100, 100a) is provided with: a branching unit (103) that branches the laser light and outputs the laser light as measurement light and reference light; a measurement light branching unit (104) that branches the measurement light and outputs the measurement light as a 1 st measurement light and a 2 nd measurement light; a reference light branching unit (105) that branches the reference light and outputs the reference light as the 1 st reference light and the 2 nd reference light; a 1 st optical system (131) having a 1 st Rayleigh length and configured to irradiate a 1 st measurement light onto the object (20); a 2 nd optical system (132) having a 2 nd Rayleigh length different from the 1 st Rayleigh length and configured to irradiate the 2 nd measurement light onto the object 20; a 1 st receiving unit (141) that receives 1 st reflected light, which is light obtained by reflecting the 1 st reference light and the 1 st measurement light on the object 20, and outputs a 1 st received signal indicating the 1 st reference light and the 1 st reflected light; and a 2 nd receiving unit (142) that receives the 2 nd reference light and the 2 nd reflected light that is the light of the 2 nd measurement light reflected by the object 20, and outputs a 2 nd reception signal indicating the 2 nd reference light and the 2 nd reflected light.)

1. An optical distance measuring device is characterized in that,

the optical distance measuring device includes:

a transmission unit including a branching unit that branches an input continuous wave laser beam and outputs the branched laser beam as measurement light and reference light, a measurement light branching unit that branches the measurement light output from the branching unit and outputs the branched measurement light as 1 st measurement light and 2 nd measurement light, a reference light branching unit that branches the reference light output from the branching unit and outputs the branched reference light as 1 st reference light and 2 nd reference light, a measurement light branching unit that branches the reference light output from the branching unit, and a transmission unit that has a 1 st optical system having a 1 st rayleigh length for irradiating an object with the 1 st measurement light, a 2 nd optical system having a 2 nd rayleigh length different from the 1 st optical length and having a focal length equal to a focal length of the 1 st optical system, for irradiating the object with the 2 nd measurement light;

a 1 st receiving unit that receives 1 st reflected light that is light obtained by reflecting the 1 st reference light and the 1 st measurement light on the object and outputs a 1 st received signal indicating the 1 st reference light and the 1 st reflected light; and

and a 2 nd receiving unit that receives 2 nd reflected light that is light obtained by reflecting the 2 nd reference light and the 2 nd measurement light on the object, and outputs a 2 nd reception signal indicating the 2 nd reference light and the 2 nd reflected light.

2. The optical distance measuring device according to claim 1,

the optical distance measuring device includes:

a frequency measuring unit that measures the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on the 1 st reception signal, outputs 1 st signal information indicating the measured intensity of each frequency component of the 1 st reference light and the 1 st reflected light, measures the intensity of each frequency component of the 2 nd reference light and the 2 nd reflected light based on the 2 nd reception signal, and outputs 2 nd signal information indicating the measured intensity of each frequency component of the 2 nd reference light and the 2 nd reflected light; and

and a distance calculation unit that calculates a distance from the transmission unit to the object based on the 1 st signal information or the 2 nd signal information output from the frequency measurement unit, and outputs distance information indicating the calculated distance from the transmission unit to the object.

3. The optical distance measuring device according to claim 2,

the frequency measuring unit measures the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on a signal obtained by combining the 1 st received signal and the 2 nd received signal, and outputs 1 st signal information indicating the measured intensity of each frequency component of the 1 st reference light and the 1 st reflected light.

4. The optical distance measuring device according to claim 2,

the measurement light branching unit branches the measurement light output from the branching unit by polarization separation, and outputs the branched measurement light as 1 st polarization measurement light and 2 nd polarization measurement light, wherein the 1 st polarization measurement light is the 1 st measurement light and the 2 nd polarization measurement light is the 2 nd measurement light,

the reference light branching unit branches the reference light output from the branching unit by polarization separation, and outputs the branched reference light as 1 st polarized reference light and 2 nd polarized reference light, wherein the 1 st polarized reference light is the 1 st reference light, and the 2 nd polarized reference light is the 2 nd reference light.

5. The optical distance measuring device according to claim 4,

the frequency measuring unit measures the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on the 1 st received signal or the 2 nd received signal by a polarization diversity method, and outputs 1 st signal information indicating the measured intensity of each frequency component of the 1 st reference light and the 1 st reflected light.

6. The optical distance measuring device according to any one of claims 1 to 5,

the transmission unit has a scanning unit that performs wavelength scanning of the input laser light and outputs the scanned laser light as scanning light,

the branching unit branches the scanning light output from the scanning unit and outputs the branched scanning light as the measurement light and the reference light,

the 1 st receiving unit includes:

a 1 st light interference unit configured to cause the 1 st reference light and the 1 st reflected light to interfere with each other, and output an interference light in which the 1 st reference light and the 1 st reflected light interfere with each other as a 1 st interference light;

a 1 st photoelectric conversion unit that photoelectrically converts the 1 st interference light output by the 1 st optical interference unit and outputs a 1 st analog signal representing the 1 st interference light; and

a 1 st digital conversion unit that performs A/D conversion on the 1 st analog signal and outputs the 1 st analog signal after the A/D conversion as the 1 st reception signal, the 1 st reception signal being a digital signal,

the 2 nd receiving unit includes:

a 2 nd light interference unit configured to cause the 2 nd reference light and the 2 nd reflected light to interfere with each other, and output interference light in which the 2 nd reference light and the 2 nd reflected light interfere with each other as 2 nd interference light;

a 2 nd photoelectric conversion unit that photoelectrically converts the 2 nd interference light output by the 2 nd optical interference unit and outputs a 2 nd analog signal representing the 2 nd interference light; and

and a 2 nd digital conversion unit that performs a/D conversion on the 2 nd analog signal and outputs the 2 nd analog signal after the a/D conversion as the 2 nd reception signal, the 2 nd reception signal being a digital signal.

7. The optical distance measuring device according to any one of claims 1 to 5,

the laser light branched by the branch portion is the laser light having a plurality of frequencies,

the 1 st receiving unit includes:

a 1 st combining unit that combines the 1 st reference light and the 1 st reflected light and outputs the combined 1 st reference light and 1 st reflected light as a 1 st combined light;

a 1 st spectroscopic unit that spatially spectrally separates the 1 st combined light output from the 1 st combining unit and irradiates the 1 st combined light after spectral separation as 1 st spectrally separated light; and

a 1 st photoelectric conversion unit having photoelectric elements arranged in an array, receiving the 1 st spectrally separated light irradiated from the 1 st spectroscopic unit, and outputting information indicating the intensity of the 1 st combined light as the 1 st reception signal in association with the position of each of the photoelectric elements arranged in the array,

the 2 nd receiving unit includes:

a 2 nd combining unit that combines the 2 nd reference light and the 2 nd reflected light and outputs the 2 nd reference light and the 2 nd reflected light after the combination as a 2 nd combined light;

a 2 nd spectroscopic unit that spatially spectrally separates the 2 nd synthesized light output from the 2 nd synthesizing unit and irradiates the 2 nd synthesized light after spectral separation as a 2 nd spectrally separated light; and

and a 2 nd photoelectric conversion unit including photoelectric elements arranged in an array, receiving the 2 nd spectrally separated light irradiated from the 2 nd spectroscopic unit, and outputting information indicating an intensity of the 2 nd combined light as the 2 nd reception signal in association with a position of each of the photoelectric elements arranged in the array.

Technical Field

The present invention relates to an optical distance measuring device.

Background

The method for optical ranging comprises the following steps: the distance from the light source to the object is measured by a pulse propagation method, a triangulation method, a confocal method, a white interference method, a wavelength scanning interference method, or the like using the light emitted from the light source. Among these methods, the white interference method, the wavelength scanning interference method, and the like are interference methods using interference phenomena of light.

The interference method is a method in which light emitted from a light source is divided into measurement light and reference light, reflected light that is light reflected by an object is caused to interfere with the reference light, and a distance from the light source to the object is measured on the basis of a condition that the reflected light and the reference light are mutually intensified.

For example, a white interference method such as a spectral domain method uses a light source that emits light in a wide band. The white interference method divides a wide band of light emitted from a light source into measurement light and reference light. The white interference method performs spatial spectral separation by a spectroscope, and measures the distance from a light source to an object based on the interference condition between the reflected light after spectral separation and the reference light after spectral separation.

In addition, for example, the wavelength scanning interference method performs wavelength scanning on light emitted from a light source. The wavelength scanning interference method divides the light after wavelength scanning into measurement light and reference light. The wavelength scanning interference method causes interference between reflected light, which is light obtained by reflecting measurement light obtained by branching light having a scanned wavelength on an object, and reference light obtained by branching light having a scanned wavelength. The wavelength scanning interference method measures the distance from a light source to an object by measuring the frequency of reflected light and the frequency of reference light.

For example, non-patent document 1 discloses a wavelength scanning Optical interference Tomography (SS-OCT) apparatus in which an Optical distance measuring device based on a wavelength scanning interference method is applied to medical use.

Documents of the prior art

Non-patent document

Non-patent document 1: spring name plus, "light コヒーレンストモグラフィ" (OCT) ", [ online ], flat to 22 years, MEDICAL photosonics, [ flat to 31 years, 2 months, 4 days retrieval ], internet < URL: http:// www.medicalphotonics.jp/pdf/mp0001/0001_029.pdf >

Disclosure of Invention

Problems to be solved by the invention

However, the conventional optical distance measuring device has the following problems: the range of the distance from the light source to the object, which can be measured by one measurement, is limited to the range of the focal length of the optical system for irradiating the object with the measurement light.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical distance measuring device capable of measuring a distance to an object with high accuracy while extending the range of distance measurement.

Means for solving the problems

The optical distance measuring device of the present invention includes: a transmission unit having a branching unit, a measurement light branching unit, a reference light branching unit, a 1 st optical system and a 2 nd optical system, wherein the branching section branches the input continuous wave laser light and outputs the branched laser light as measurement light and reference light, the measurement light branching unit branches the measurement light output from the branching unit, outputs the branched measurement light as a 1 st measurement light and a 2 nd measurement light, the reference light branching unit branches the reference light output from the branching unit, outputs the branched reference light as the 1 st reference light and the 2 nd reference light, the 1 st optical system has a 1 st Rayleigh length and irradiates the 1 st measurement light to the object, the 2 nd optical system has a 2 nd Rayleigh length different from the 1 st Rayleigh length, and has a focal length equal to that of the 1 st optical system, for irradiating the 2 nd measurement light to the object; a 1 st receiving unit that receives 1 st reflected light that is light obtained by reflecting the 1 st reference light and the 1 st measurement light on the object and outputs a 1 st received signal indicating the 1 st reference light and the 1 st reflected light; and a 2 nd receiving unit that receives the 2 nd reference light and a 2 nd reflected light that is a light obtained by reflecting the 2 nd measurement light on the object, and outputs a 2 nd reception signal indicating the 2 nd reference light and the 2 nd reflected light.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the range of distance measurement from an object can be extended and the distance can be measured with high accuracy.

Drawings

Fig. 1 is a block diagram showing an example of a configuration of a main part of an optical distance measuring apparatus according to embodiment 1.

Fig. 2 is a diagram showing an example of a processing apparatus to which the optical distance measuring apparatus according to embodiment 1 is applied.

Fig. 3 is a diagram showing an example of a processing apparatus to which the optical distance measuring apparatus according to embodiment 1 is applied.

Fig. 4A is a diagram illustrating an example of a distance between the transmission unit and the object in embodiment 1. Fig. 4B is a diagram illustrating an example of the relationship between the 1 st reference light and the 1 st reflected light input to the 1 st light interference unit in the case where the distance between the transmission unit and the object is X2 in embodiment 1. Fig. 4C is a diagram showing the spectrum of the 1 st interference light measured by the frequency measuring unit based on the 1 st received signal at a certain time point T1 shown in fig. 4B. Fig. 4D is a diagram showing the spectrum of the 1 st interference light measured by the frequency measuring unit based on the 1 st received signal at a certain time point at the position of the object shown in fig. 4A.

Fig. 5A is a diagram showing an example of a relationship between the rayleigh length of the optical system and a range in which the distance calculation unit of embodiment 1 can calculate the distance from the transmission unit to the object. Fig. 5B is a diagram illustrating an example of a relationship between the rayleigh length of the optical system and the intensity of the reflected wave in the case where the distance from the transmission unit to the object is fixed in embodiment 1. Fig. 5C is a diagram showing an example of a relationship between the intensity of the reflected wave and an error included in the distance from the transmission unit to the object calculated by the distance calculation unit according to embodiment 1.

Fig. 6 is a diagram showing an example of paths of the 1 st and 2 nd measurement lights and the 1 st and 2 nd reflected lights which are reflected lights of the 1 st and 2 nd measurement lights reflected on the object in embodiment 1.

Fig. 7 is a block diagram showing an example of the configuration of a main part of the optical distance measuring apparatus according to embodiment 2.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1.

Fig. 1 is a block diagram showing an example of the configuration of a main part of an optical distance measuring apparatus 100 according to embodiment 1.

The optical distance measuring device 100 includes a laser light source 101, a scanning unit 102, a branching unit 103, a measurement optical branching unit 104, a reference optical branching unit 105, a delay adjustment unit 106, a 1 st optical circulator 121, a 2 nd optical circulator 122, a 1 st optical system 131, a 2 nd optical system 132, a 1 st optical interference unit 151, a 2 nd optical interference unit 152, a 1 st photoelectric conversion unit 161, a 2 nd photoelectric conversion unit 162, a 1 st digital conversion unit 171, a 2 nd digital conversion unit 172, a frequency measuring unit 181, a distance calculating unit 182, and an information transmitting unit 190.

The laser light source 101 emits laser light as continuous light. In embodiment 1, the laser light source 101 is a light source that emits laser light of a predetermined frequency, such as a gas laser or a semiconductor laser.

The laser light source 101 is not necessarily configured in the optical distance measuring apparatus 100 according to embodiment 1. For example, the optical distance measuring apparatus 100 may be operated by receiving laser light emitted from an external laser light generating apparatus having the laser light source 101.

The scanner unit 102 receives laser light emitted from the laser light source 101. The scanning unit 102 performs wavelength scanning of the input laser light and outputs the scanned laser light as scanning light. The scanning light output from the scanning unit 102 is a continuous wave laser light.

The branching unit 103 is configured by an optical coupler or the like, branches the input continuous wave laser light, and outputs the branched laser light as measurement light and reference light. More specifically, the branching unit 103 branches the scanning light, which is the laser light emitted from the scanning unit 102, and outputs the branched laser light as the measurement light and the reference light.

The measurement light branching unit 104 branches the measurement light output from the branching unit 103, and outputs the branched measurement light as the 1 st measurement light and the 2 nd measurement light. Specifically, the measurement light branching unit 104 is constituted by a PBS (Polarizing Beam Splitter) or the like, and the measurement light branching unit 104 branches the measurement light output from the branching unit 103 by polarization separation, and outputs the branched measurement light as the 1 st polarized measurement light which is the 1 st measurement light and the 2 nd polarized measurement light which is the 2 nd polarized measurement light. The 1 st polarization measurement light and the 2 nd polarization measurement light are, for example, linearly polarized lights having different vibration directions from each other.

The 1 st optical circulator 121 is composed of, for example, a three-port optical circulator, and guides the 1 st measurement light output from the measurement light splitting unit 104 to the 1 st optical system 131. Specifically, the 1 st optical circulator 121 guides the 1 st polarization measurement light, which is the 1 st measurement light output from the measurement light branching unit 104, to the 1 st optical system 131.

The 1 st optical system 131 irradiates the 1 st measurement light to the object 20. Specifically, for example, the 1 st optical system 131 is configured by a lens such as 1 or more transmission lenses or 1 or more reflection lenses, and the 1 st optical system 131 enlarges the beam diameter of the 1 st polarized measurement light guided to the 1 st optical system 131 by the 1 st optical circulator 121 and irradiates the 1 st polarized measurement light with the enlarged beam diameter to the object 20.

The 1 st optical system 131 has a 1 st rayleigh length. The rayleigh length is 1 value indicating the light condensing characteristic of the optical system in the laser light, and the diameter of the laser light condensed by the optical system is a value indicating a range of lengths in a direction from the optical system toward the focal point, which is considered to be sufficiently small.

The 1 st optical system 131 guides the 1 st reflected light, which is the light of the 1 st polarization measurement light irradiated to the object 20 and reflected on the object 20, to the 1 st optical circulator 121.

The 1 st optical circulator 121 guides the 1 st reflected light to the 1 st optical interference unit 151.

The 2 nd optical circulator 122 is composed of, for example, a three-port optical circulator, and guides the 2 nd measurement light output from the measurement light branching unit 104 to the 2 nd optical system 132. Specifically, the 2 nd optical circulator 122 guides the 2 nd polarization measurement light, which is the 2 nd measurement light output from the measurement light branching unit 104, to the 2 nd optical system 132.

The 2 nd optical system 132 irradiates the 2 nd measurement light to the object 20. Specifically, for example, the 2 nd optical system 132 is configured by a lens such as 1 or more transmission lenses or 1 or more reflection lenses, and the 2 nd optical system 132 enlarges the beam diameter of the 2 nd polarization measurement light guided to the 1 st optical system 131 by the 2 nd optical circulator 122 and irradiates the 2 nd polarization measurement light with the enlarged beam diameter toward the object 20.

The 2 nd optical system 132 has a 2 nd rayleigh length different from the 1 st rayleigh length.

The 2 nd optical system 132 has a focal length equal to that of the 1 st optical system 131. The equal focal lengths are not limited to exactly equal focal lengths, and include approximately equal focal lengths.

The 2 nd optical system 132 guides the 2 nd reflected light, which is the light of the 2 nd polarization measurement light irradiated to the object 20 and reflected on the object 20, to the 2 nd optical circulator 122.

The 2 nd optical circulator 122 guides the 2 nd reflected light to the 2 nd optical interference unit 152.

The reference light branching unit 105 branches the reference light output from the branching unit 103, and outputs the branched reference light as the 1 st reference light and the 2 nd reference light. Specifically, the reference light branching unit 105 is configured by PBS or the like, and the reference light branching unit 105 branches the reference light output from the branching unit 103 by polarization separation, and outputs the branched reference light as the 1 st polarized reference light, which is the 1 st reference light, and the 2 nd polarized reference light, which is the 2 nd reference light. The 1 st polarization reference light and the 2 nd polarization reference light are, for example, linearly polarized lights having different vibration directions from each other.

In the following description, the vibration direction of the 1 st polarized measurement light is the same as the vibration direction of the 1 st polarized reference light, and the vibration direction of the 2 nd polarized measurement light is the same as the vibration direction of the 2 nd polarized reference light.

The 1 st reference light output from the reference light branching unit 105 is guided to the 1 st light interference unit 151.

The 2 nd reference light output from the reference light branching unit 105 is guided to the 2 nd light interference unit 152.

The delay adjustment unit 106 adjusts the path difference between the measurement light output from the branching unit 103 and the reference light.

The optical distance measuring device 100 according to embodiment 1 includes a laser light source 101, a scanning unit 102, a branching unit 103, a measurement optical branching unit 104, a reference optical branching unit 105, a delay adjustment unit 106, a 1 st optical circulator 121, a 2 nd optical circulator 122, a 1 st optical system 131, and a 2 nd optical system 132, and constitutes a transmission unit 110.

The 1 st light interference unit 151 causes the 1 st reference light to interfere with the 1 st reflected light, and outputs interference light in which the 1 st reference light and the 1 st reflected light interfere as 1 st interference light. Specifically, the 1 st light interference unit 151 is composed of, for example, a 90-degree light mixer, and outputs the 1 st interference light by combining the 1 st reference light and the 1 st reflected light.

The 1 st photoelectric conversion unit 161 photoelectrically converts the 1 st interference light output from the 1 st optical interference unit 151 and outputs a 1 st analog signal representing the 1 st interference light.

The 1 st digital converter 171 a/D converts the 1 st analog signal and outputs the 1 st analog signal after the a/D conversion as a 1 st reception signal, the 1 st reception signal being a digital signal.

The optical distance measuring device 100 according to embodiment 1 includes a 1 st light interference unit 151, a 1 st photoelectric conversion unit 161, and a 1 st digital conversion unit 171, thereby constituting a 1 st receiving unit 141.

That is, the 1 st receiving unit 141 receives the 1 st reference light and the 1 st reflected light, which is the light obtained by reflecting the 1 st measurement light on the object 20, and outputs the 1 st reception signal indicating the 1 st reference light and the 1 st reflected light.

The 2 nd light interference unit 152 causes the 2 nd reference light to interfere with the 2 nd reflected light, and outputs interference light in which the 2 nd reference light and the 2 nd reflected light interfere as 2 nd interference light. Specifically, the 2 nd light interference unit 152 is composed of, for example, a 90-degree light mixer, and outputs the 2 nd interference light by combining the 2 nd reference light and the 2 nd reflected light.

The 2 nd photoelectric conversion unit 162 photoelectrically converts the 2 nd interference light output from the 2 nd optical interference unit 152 and outputs a 2 nd analog signal representing the 2 nd interference light.

The 2 nd digital conversion section 172 a/D converts the 2 nd analog signal and outputs the a/D converted 2 nd analog signal as a 2 nd reception signal, the 2 nd reception signal being a digital signal.

The optical distance measuring device 100 according to embodiment 1 includes the 2 nd light interference unit 152, the 2 nd photoelectric conversion unit 162, and the 2 nd digital conversion unit 172, thereby configuring the 2 nd receiving unit 142.

That is, the 2 nd receiving unit 142 receives the 2 nd reference light and the 2 nd reflected light, which is the light obtained by reflecting the 2 nd measurement light on the object 20, and outputs the 2 nd reception signal indicating the 2 nd reference light and the 2 nd reflected light.

The frequency measuring unit 181 measures the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on the 1 st received signal. The frequency measuring unit 181 outputs 1 st signal information indicating the measured intensity of each frequency component of the 1 st reference light and the 1 st reflected light.

The frequency measuring unit 181 measures the intensity of each frequency component of the 2 nd reference light and the 2 nd reflected light based on the 2 nd reception signal. The frequency measuring unit 181 outputs the 2 nd signal information indicating the measured intensity of each frequency component of the 2 nd reference light and the 2 nd reflected light.

More specifically, for example, the frequency measurement unit 181 performs fourier transform on the 1 st received signal to measure the intensity of each frequency component of the 1 st reference light and the 1 st reflected light. The frequency measurement unit 181 performs fourier transform on the 2 nd received signal to measure the intensity of each frequency component of the 2 nd reference light and the 2 nd reflected light.

The distance calculation unit 182 calculates the distance from the transmission unit 110 to the object 20 based on the 1 st signal information or the 2 nd signal information output from the frequency measurement unit 181. The distance calculation unit 182 outputs distance information indicating the distance from the transmission unit 110 to the object 20 calculated by the distance calculation unit 182. The distance from the transmission unit 110 to the object 20 is, for example, the distance from the 1 st optical system 131 or the 2 nd optical system 132 to the object 20. The distance from the transmission unit 110 to the object 20 is not limited to the distance from the 1 st optical system 131 or the 2 nd optical system 132 to the object 20, and may be a distance from the reference structure of the transmission unit 110 to the object 20.

Specifically, for example, the distance calculation unit 182 calculates the distance from the transmission unit 110 to the object 20 based on the 1 st signal information or the 2 nd signal information output from the frequency measurement unit 181 by the polarization diversity method. The distance calculation unit 182 outputs distance information indicating the distance from the transmission unit 110 to the object 20 calculated by the distance calculation unit 182.

The distance calculation unit 182 may calculate the distance from the transmission unit 110 to the object 20 based on the 1 st signal information and the 2 nd signal information output from the frequency measurement unit 181.

The distance from the transmitting unit 110 to the object 20 calculated by the distance calculating unit 182 is, for example, the distance from the 1 st optical circulator 121, the 2 nd optical circulator 122, the 1 st optical system 131, or the 2 nd optical system 132 to the object 20.

For example, when the distance from the transmitting unit 110 to the object 20 calculated by the distance calculating unit 182 is the distance from the 1 st optical circulator 121 to the object 20, the delay adjusting unit 106 adjusts the path difference between the sum of the following two path lengths, each of which is: a path length from the measurement light output from the branching unit 103 to the 1 st measurement light via the measurement light branching unit 104 until the 1 st measurement light is output to the 1 st optical system 131 via the 1 st optical circulator 121; and the path length from the 1 st reflected light input to the 1 st optical circulator 121 to the 1 st optical interference unit 151.

The information transmitting unit 190 performs control for transmitting distance information indicating the distance between the transmitting unit 110 and the object 20, which is output from the distance calculating unit 182, to the outside.

Further, the laser light source 101 and the scanning unit 102, the scanning unit 102 and the branching unit 103, the branching unit 103 and the measurement light branching unit 104, the branching unit 103 and the delay adjustment unit 106, and the delay adjustment unit 106 and the measurement light branching unit 104 are connected by, for example, optical fibers, and the laser light is guided through the optical fibers. Further, between the measurement optical branching unit 104 and the 1 st optical circulator 121, between the 1 st optical circulator 121 and the 1 st optical interference unit 151, between the measurement optical branching unit 104 and the 2 nd optical circulator 122, between the 2 nd optical circulator 122 and the 2 nd optical interference unit 152, between the measurement optical branching unit 104 and the 1 st optical interference unit 151, and between the measurement optical branching unit 104 and the 2 nd optical interference unit 152 are connected by, for example, an optical fiber which is a polarization maintaining optical fiber maintaining an amplitude direction of polarization, and laser light which is polarized light is guided through the optical fiber.

An application example of the optical distance measuring apparatus 100 according to embodiment 1 will be described with reference to fig. 2 and 3.

Fig. 2 and 3 are diagrams showing an example of the processing apparatus 10 to which the optical distance measuring apparatus 100 according to embodiment 1 is applied.

The machining device 10 shown in fig. 2 includes a chuck 12, a machining head 11, a head movement control unit 13, and a head movement mechanism 14.

The object 20 is an object to be processed by the processing apparatus 10.

The chuck 12 is a pedestal for fixing the object 20.

The machining head 11 is a portion for machining the object 20. The machining head 11 may perform machining while contacting the object 20 when machining the object 20, or may perform machining on the object 20 in a non-contact state.

The head movement control unit 13 acquires the distance information output from the optical distance measuring device 100, and generates a control signal for moving the machining head 11 with respect to the chuck 12 based on the distance information. The head movement control unit 13 outputs the generated control signal to the head movement mechanism 14.

The head movement mechanism 14 receives a control signal output from the head movement control unit 13, and moves the machining head 11 relative to the chuck 12 based on the control signal.

The machining device 10 shown in fig. 3 includes a chuck 12, a machining head 11, a chuck movement control unit 15, and a chuck movement mechanism 16.

The chuck 12 and the machining head 11 are the same as the chuck 12 and the machining head 11 shown in fig. 2, and therefore, description thereof is omitted.

The chuck movement control unit 15 acquires the distance information output from the optical distance measuring device 100, and generates a control signal for moving the chuck 12 with respect to the machining head 11 based on the distance information. The chuck movement control unit 15 outputs the generated control signal to the chuck movement mechanism 16.

The chuck movement mechanism 16 receives a control signal output from the chuck movement control unit 15, and moves the chuck 12 relative to the machining head 11 based on the control signal.

In fig. 2 and 3, the 1 st optical circulator 121, the 2 nd optical circulator 122, the 1 st optical system 131, and the 2 nd optical system 132 in the optical distance measuring apparatus 100 are fixed to the machining head 11. The positions of the 1 st optical circulator 121, the 2 nd optical circulator 122, the 1 st optical system 131, and the 2 nd optical system 132 fixed on the processing head 11 are known. That is, the head movement control unit 13 or the chuck movement control unit 15 can calculate the distance between the processing head 11 and the object 20 based on the distance from the transmission unit 110 to the object 20 indicated by the distance information output from the optical distance measuring device 100.

A method for calculating the distance from the transmission unit 110 to the object 20 by the distance calculation unit 182 in embodiment 1 will be described with reference to fig. 4.

Fig. 4A is a diagram illustrating an example of the distance between the transmission unit 110 and the object 20 according to embodiment 1.

As an example, fig. 4A shows the object 20 located at positions separated from the transmitter 110 of embodiment 1 by X1, X2, and X3.

Fig. 4B is a diagram illustrating an example of the relationship between the 1 st reference light and the 1 st reflected light input to the 1 st light interference unit 151 when the distance between the transmission unit 110 and the object 20 in embodiment 1 is X2. In fig. 4B, the horizontal axis represents elapsed time, and the vertical axis represents frequency.

Since the laser light input to the branching unit 103 is scanning light, the reference light and the measurement light output from the branching unit 103, and the reflected light that is the light obtained by reflecting the measurement light on the object 20 become scanning light. That is, the frequencies of the 1 st reference light and the 1 st reflected light input to the 1 st light interference unit 151 change with time in the same manner as the scanning light. In embodiment 1, the value of the frequency change per unit time in the scanning light is known.

The 1 st reflected light is delayed from the 1 st reference light by the 1 st light interference unit 151 according to the distance between the transmission unit 110 and the object 20. Therefore, fig. 4B shows a state in which the 1 st reflected light is shifted to the right side by time Δ T2 from the 1 st reference light.

The frequency measuring unit 181 measures the intensity of each frequency component of the 1 st interference light based on the 1 st interference light at a certain time point T1.

Fig. 4C is a diagram showing the spectrum of the 1 st interference light measured by the frequency measuring unit 181 based on the 1 st received signal at a certain time point T1 shown in fig. 4B. In fig. 4C, the horizontal axis represents frequency, and the vertical axis represents intensity of the 1 st interference light.

In fig. 4C, the intensity of the 1 st interference light becomes strong in 2 bands. In fig. 4C, of 2 frequency bands in which the intensity of the 1 st interference light becomes high, the light with the frequency Fr of the high frequency is the 1 st reference light, and the light with the frequency F2 of the low frequency band is the 1 st reflected light.

The frequency measuring unit 181 generates 1 st signal information indicating that the frequency of the 1 st reference light is Fr and the frequency of the 1 st reflected light is F2, and outputs the 1 st signal information.

The distance calculation unit 182 calculates the delay time Δ T2 of the 1 st reflected light with respect to the 1 st reference light based on the 1 st signal information output from the frequency measurement unit 181 and the known value of the frequency change per unit time in the scanning light.

The distance calculation unit 182 multiplies the calculated time Δ T2 by the known light velocity, and further multiplies 1/2 by it, thereby calculating X2, which is the distance from the transmission unit 110 to the object 20.

Fig. 4D is a diagram showing the spectrum of the 1 st interference light measured by the frequency measuring unit 181 based on the 1 st received signal at a certain time point at the position of the object 20 shown in fig. 4A.

For example, as shown in fig. 4A, when the distance between the transmitter 110 and the object 20 is X1, which is shorter than X2, the difference between the frequency of the 1 st reference light and the frequency of the 1 st reflected light becomes small as shown in fig. 4D. In this case, the time during which the 1 st reflected light obtained by the calculation of the distance calculation unit 182 is delayed from the 1 st reference light is shorter than the time Δ T2 when the distance between the transmission unit 110 and the object 20 is X2.

For example, as shown in fig. 4A, when the distance between the transmitter 110 and the object 20 is X3, which is longer than X2, the difference between the frequency of the 1 st reference light and the frequency of the 1 st reflected light becomes large as shown in fig. 4D. In this case, the time during which the 1 st reflected light obtained by the calculation of the distance calculation unit 182 is delayed from the 1 st reference light is longer than the time Δ T2 when the distance between the transmission unit 110 and the object 20 is X2.

Note that, although the method of calculating the distance from the transmission unit 110 to the object 20 by the distance calculation unit 182 in embodiment 1 has been described above with reference to the 1 st reference light and the 1 st reflected light input to the 1 st optical interference unit 151 as examples, the method of calculating the distance from the transmission unit 110 to the object 20 by the distance calculation unit 182 is the same for the 2 nd reference light and the 2 nd reflected light input to the 2 nd optical interference unit 152, and therefore, the description thereof is omitted.

The distance that the distance calculation unit 182 can calculate the distance from the transmission unit 110 to the object 20 is in the vicinity of the focal length including the focal lengths of the 1 st optical system 131 and the 2 nd optical system 132. As described above, the 1 st optical system 131 and the 2 nd optical system 132 have focal lengths equal to each other.

Referring to fig. 5, a description will be given of a range in which the distance calculation unit 182 can calculate the distance from the transmission unit 110 to the object 20 when the 1 st optical system 131 or the 2 nd optical system 132 is used.

In the following, as an example, the 2 nd rayleigh length of the 2 nd optical system 132 is longer than the 1 st rayleigh length of the 1 st optical system 131.

Fig. 5A is a diagram showing an example of the relationship between the rayleigh length of the optical system and the range within which the distance calculation unit 182 can calculate the distance from the transmission unit 110 to the object 20.

As can be seen from fig. 5A, the longer the rayleigh length of the optical system is, the wider the range in which the distance calculation unit 182 can calculate the distance from the transmission unit 110 to the object 20 is.

That is, since the 2 nd rayleigh length of the 2 nd optical system 132 is longer than the 1 st rayleigh length of the 1 st optical system 131, the range of the distance from the transmitting unit 110 to the object 20 that can be calculated by the distance calculating unit 182 based on the 2 nd reception signal output by the 2 nd receiving unit 142 is wider than the range of the distance from the transmitting unit 110 to the object 20 that can be calculated based on the 1 st reception signal output by the 1 st receiving unit 141.

Fig. 5B is a diagram showing an example of a relationship between the rayleigh length of the optical system and the intensity of the reflected wave in a case where the distance from the transmission unit 110 to the object 20 is fixed.

The longer the rayleigh length, the smaller the spot diameter. Since the object 20 generally has surface roughness on the surface, the reflected light of the measurement light reflected by the object 20 has not only a regular reflection component but also a diffuse reflection component. Therefore, the larger the ratio of the diffuse reflection component, the more attenuated the reflected light returning to the optical system. The larger the spot diameter is, the larger the attenuation of the reflected light is, and the smaller the spot diameter is, the smaller the attenuation of the reflected light is. That is, the longer the rayleigh length is, the weaker the intensity of the reflected wave is, and the shorter the rayleigh length is, the stronger the intensity of the reflected wave is.

As can be seen from fig. 5B, when the distance from the transmission unit 110 to the object 20 is fixed, the longer the rayleigh length of the optical system is, the weaker the intensity of the reflected wave is.

That is, since the 2 nd rayleigh length of the 2 nd optical system 132 is longer than the 1 st rayleigh length of the 1 st optical system 131, the intensity of the 2 nd reflected wave included in the 2 nd received signal output by the 2 nd receiving unit 142 is weaker than the intensity of the 1 st reflected wave included in the 1 st received signal output by the 1 st receiving unit 141 in the distance calculating unit 182.

Fig. 5C is a diagram showing an example of the relationship between the intensity of the reflected wave and the error included in the distance from the transmission unit 110 to the object 20 calculated by the distance calculation unit 182.

As can be seen from fig. 5C, when the distance from the transmission unit 110 to the object 20 is fixed, the stronger the intensity of the reflected wave is, the smaller the error included in the distance from the transmission unit 110 to the object 20 calculated by the distance calculation unit 182 is.

That is, since the intensity of the 2 nd reflected wave included in the 2 nd received signal output by the 2 nd receiving unit 142 is weaker than the intensity of the 1 st reflected wave included in the 1 st received signal output by the 1 st receiving unit 141, the error included in the distance from the transmitting unit 110 to the object 20 calculated by the distance calculating unit 182 based on the 2 nd received signal output by the 2 nd receiving unit 142 is larger than the error included in the distance from the transmitting unit 110 to the object 20 calculated based on the 1 st received signal output by the 1 st receiving unit 141.

As described above, the measurement range is narrower in the case where the distance from the transmission unit 110 to the object 20 is measured using the 1 st optical system 131 than in the case where the distance from the transmission unit 110 to the object 20 is measured using the 2 nd optical system 132, but the measurement error is small.

For example, first, as a step 1, the optical distance measuring apparatus 100 measures a rough distance from the transmitting unit 110 to the object 20 based on the 2 nd reception signal output from the 2 nd receiving unit 142 for the object 20 whose distance from the transmitting unit 110 to the object is unknown.

Next, as a 2 nd step, the machining device 10 moves the machining head 11 or the chuck 12 based on the distance information indicating the rough distance from the transmission unit 110 to the object 20 acquired from the optical distance measuring device 100, and performs rough alignment.

Next, as step 3, the optical distance measuring apparatus 100 calculates an accurate distance from the transmitting unit 110 to the object 20 based on the 1 st received signal output from the 1 st receiving unit 141.

Referring to fig. 6, an effect of the optical distance measuring device 100 in measuring the distance from the transmission unit 110 to the object 20 using the 1 st polarization measurement light, the 2 nd polarization measurement light, and the 1 st polarization reference light and the 2 nd polarization reference light will be described.

Fig. 6 is a diagram showing an example of paths of the 1 st measurement light and the 2 nd measurement light, and the 1 st reflected light and the 2 nd reflected light which are reflected light of the 1 st measurement light and the 2 nd measurement light reflected on the object 20.

The surface of the object 20 irradiated with the 1 st measurement light and the 2 nd measurement light has surface roughness.

Therefore, as shown in fig. 6, the 1 st reflected light and the 2 nd reflected light of the 1 st measurement light and the 2 nd measurement light reflected on the surface have not only a regular reflection component reflected toward the same path as the 1 st measurement light and the 2 nd measurement light but also a diffuse reflection component uniformly spread and reflected at a wide angle. Therefore, the reflected light entering the 1 st optical system 131 has a component of the 1 st reflected light and a component of stray light that is diffusely reflected on the surface of the 2 nd reflected light. The reflected light entering the 2 nd optical system 132 has a component of the 2 nd reflected light and a component of stray light that is diffusely reflected on the surface of the 1 st reflected light.

On the other hand, as described above, the optical distance measuring apparatus 100 according to embodiment 1 measures the distance from the transmitting unit 110 to the object 20 using the 1 st polarized measurement light and the 2 nd polarized measurement light branched by the measurement light branching unit 104 polarizing and separating the measurement light, and the 1 st polarized reference light and the 2 nd polarized reference light branched by the reference light branching unit 105 polarizing and separating the reference light.

2 polarized waves with different vibration directions do not interfere. Therefore, the component of the stray light that is diffusely reflected on the surface of the 2 nd reflected light entering the 1 st optical system 131 does not interfere with the component of the 1 st reflected light in the 1 st light interference portion 151. Therefore, the frequency measuring unit 181 can accurately measure the frequency of the 1 st measurement light in the 1 st reception signal based on the component of the 1 st reflected light. Similarly, the component of the stray light that is diffusely reflected on the surface of the 1 st reflected light incident on the 2 nd optical system 132 does not interfere with the component of the 2 nd reflected light in the 2 nd light interference portion 152. Therefore, the frequency measuring unit 181 can accurately measure the frequency of the 2 nd measurement light in the 2 nd reception signal based on the component of the 2 nd reflected light.

In the above-described step 3, when the optical distance measuring apparatus 100 measures the distance from the transmitter 110 to the object 20, the accurate distance from the transmitter 110 to the object 20 may be calculated based on the 1 st received signal output from the 1 st receiver 141 and the 2 nd received signal output from the 2 nd receiver 142.

More specifically, for example, the frequency measuring unit 181 may measure the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on a signal obtained by combining the 1 st received signal and the 2 nd received signal, and output the 1 st signal information indicating the measured intensity of each frequency component of the 1 st reference light and the 1 st reflected light. The distance calculating unit 182 calculates the distance from the transmitting unit 110 to the object 20 based on the 1 st signal information output from the frequency measuring unit 181.

With this configuration, in step 3, the optical distance measuring apparatus 100 can calculate the distance from the transmission unit 110 to the object 20 more accurately.

In addition, for example, in the 3 rd step, the frequency measuring unit 181 may measure the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on the 1 st received signal or the 2 nd received signal by the polarization diversity method, and output the 1 st signal information indicating the measured intensity of each frequency component of the 1 st reference light and the 1 st reflected light.

For example, the polarization ratio between the 1 st polarization measurement light and the 2 nd polarization measurement light varies depending on the ambient temperature in the optical distance measuring apparatus 100, disturbance generated when propagating through the optical fiber, the material of the object 20, the state of the surface of the object 20, and the like. When the frequency measuring unit 181 measures the frequency using only the 1 st received signal generated by only one of the polarized waves, the 1 st reflected wave reception sensitivity in the 1 st receiving unit 141 may be degraded because 2 polarized waves having different vibration directions do not interfere with each other when the polarization ratio varies.

On the other hand, since the total of the intensities of the 2 polarized waves is fixed, even if the intensity of one polarization decreases, the intensity of the other polarization increases by the amount of the decrease.

Therefore, the frequency measuring unit 181 measures the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on the 1 st received signal or the 2 nd received signal generated by the 2 polarized waves, respectively, by the polarization diversity method, and outputs the 1 st signal information indicating the measured intensity of each frequency component of the 1 st reference light and the 1 st reflected light.

With this configuration, in step 3, the optical distance measuring apparatus 100 increases the resistance to the variation in the polarization ratio between the 1 st polarization measurement light and the 2 nd polarization measurement light, and can calculate the distance from the transmission unit 110 to the object 20 more accurately even when the polarization ratio varies.

As described above, the optical distance measuring apparatus 100 includes: a transmission unit 110 having a branching unit 103, a measurement light branching unit 104, a reference light branching unit 105, a 1 st optical system 131 and a 2 nd optical system 132, the branching unit 103 branching an input continuous wave laser beam and outputting the branched laser beam as measurement light and reference light, the measurement light branching unit 104 branching the measurement light output from the branching unit 103 and outputting the branched measurement light as 1 st measurement light and 2 nd measurement light, the reference light branching unit 105 branching the reference light output from the branching unit 103 and outputting the branched reference light as 1 st reference light and 2 nd reference light, the 1 st optical system 131 having a 1 st rayleigh length for irradiating the 1 st measurement light to the object 20, the 2 nd optical system 132 having a 2 nd rayleigh length different from the 1 st rayleigh length and having a focal length equal to a focal length of the 1 st optical system 131, for irradiating the object 20 with the 2 nd measurement light; a 1 st receiving unit 141 that receives the 1 st reference light and the 1 st reflected light, which is the light of the 1 st measurement light reflected by the object 20, and outputs a 1 st reception signal indicating the 1 st reference light and the 1 st reflected light; and a 2 nd receiving unit 142 that receives the 2 nd reference light and the 2 nd reflected light, which is the light of the 2 nd measurement light reflected by the object 20, and outputs a 2 nd reception signal indicating the 2 nd reference light and the 2 nd reflected light.

With this configuration, the optical distance measuring apparatus 100 can increase the range of distance measurement from the transmission unit 110 to the object 20, and can measure the distance with high accuracy.

In addition to the above configuration, the optical distance measuring apparatus 100 further includes: a frequency measuring unit 181 that measures the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on the 1 st received signal, outputs 1 st signal information indicating the measured intensity of each frequency component of the 1 st reference light and the 1 st reflected light, measures the intensity of each frequency component of the 2 nd reference light and the 2 nd reflected light based on the 2 nd received signal, and outputs 2 nd signal information indicating the measured intensity of each frequency component of the 2 nd reference light and the 2 nd reflected light; and a distance calculation unit 182 that calculates the distance from the transmission unit 110 to the object 20 based on the 1 st signal information or the 2 nd signal information output from the frequency measurement unit 181, and outputs distance information indicating the calculated distance from the transmission unit 110 to the object 20.

With this configuration, the optical distance measuring apparatus 100 can increase the range of distance measurement from the transmission unit 110 to the object 20, and can measure the distance with high accuracy.

The frequency measuring unit 181 is configured to measure the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on a signal obtained by combining the 1 st received signal and the 2 nd received signal, and output 1 st signal information indicating the measured intensity of each frequency component of the 1 st reference light and the 1 st reflected light.

With such a configuration, the optical distance measuring device 100 can measure the distance from the transmitter 110 to the object 20 with higher accuracy.

In addition to the above configuration, the optical distance measuring apparatus 100 is configured such that the measurement light branching unit 104 branches the measurement light output from the branching unit 103 by polarization separation, outputs the branched measurement light as the 1 st measurement light, i.e., the 1 st polarization measurement light, and the 2 nd polarization measurement light, i.e., the 2 nd measurement light, and the reference light branching unit 105 branches the reference light output from the branching unit 103 by polarization separation, and outputs the branched reference light as the 1 st polarization reference light, i.e., the 1 st polarization reference light, and the 2 nd polarization reference light, i.e., the 2 nd polarization reference light.

With this configuration, the optical distance measuring apparatus 100 can increase the range of distance measurement from the transmitter 110 to the object 20, and can measure the distance with higher accuracy.

In addition to the above configuration, the optical distance measuring apparatus 100 is configured such that the frequency measuring unit 181 measures the intensity of each of the frequency components of the 1 st reference light and the 1 st reflected light based on the 1 st received signal or the 2 nd received signal by the polarization diversity method, and outputs the 1 st signal information indicating the measured intensity of each of the frequency components of the 1 st reference light and the 1 st reflected light.

With this configuration, the optical distance measuring apparatus 100 has an increased resistance to the variation in the polarization ratio between the 1 st polarization measurement light and the 2 nd polarization measurement light, and can measure the distance from the transmission unit 110 to the object 20 with higher accuracy even when the polarization ratio varies.

In addition to the above configuration, the optical distance measuring apparatus 100 is configured such that the transmitting unit 110 includes a scanning unit 102 that scans the input laser light with a wavelength and outputs the scanned laser light as scanning light, the branching unit 103 branches the scanning light output by the scanning unit 102 and outputs the branched scanning light as measurement light and reference light, and the 1 st receiving unit 141 includes: a 1 st light interference unit 151 configured to cause the 1 st reference light to interfere with the 1 st reflected light, and output interference light in which the 1 st reference light and the 1 st reflected light interfere with each other as 1 st interference light; a 1 st photoelectric conversion unit 161 that photoelectrically converts the 1 st interference light output from the 1 st optical interference unit 151 and outputs a 1 st analog signal representing the 1 st interference light; and a 1 st digital converter 171 that a/D converts the 1 st analog signal and outputs the a/D converted 1 st analog signal as a 1 st reception signal, the 1 st reception signal being a digital signal, the 2 nd reception unit 142 including: a 2 nd light interference unit 152 that causes the 2 nd reference light to interfere with the 2 nd reflected light, and outputs interference light in which the 2 nd reference light and the 2 nd reflected light interfere as 2 nd interference light; a 2 nd photoelectric conversion unit 162 that photoelectrically converts the 2 nd interference light output from the 2 nd optical interference unit 152 and outputs a 2 nd analog signal representing the 2 nd interference light; and a 2 nd digital conversion unit 172 that a/D converts the 2 nd analog signal and outputs the a/D converted 2 nd analog signal as a 2 nd reception signal, the 2 nd reception signal being a digital signal.

With this configuration, the optical distance measuring apparatus 100 can increase the range of distance measurement from the transmission unit 110 to the object 20, and can measure the distance with high accuracy.

Embodiment 2.

The optical distance measuring apparatus 100a according to embodiment 2 will be described with reference to fig. 7.

The optical distance measuring apparatus 100a is obtained by replacing the laser light source 101 and the scanner unit 102 in the optical distance measuring apparatus 100 of embodiment 1 with the laser light source 101 a. The optical distance measuring device 100a is obtained by replacing the transmitting unit 110, the 1 st receiving unit 141, the 2 nd receiving unit 142, the frequency measuring unit 181, and the distance calculating unit 182 in the optical distance measuring device 100 according to embodiment 1 with the transmitting unit 110a, the 1 st receiving unit 141a, the 2 nd receiving unit 142a, the frequency measuring unit 181a, and the distance calculating unit 182 a.

Fig. 7 is a block diagram showing an example of the configuration of a main part of the optical distance measuring apparatus 100a according to embodiment 2.

The optical distance measuring device 100a includes a laser light source 101a, a branching unit 103a, a measurement optical branching unit 104, a reference optical branching unit 105, a delay adjustment unit 106, a 1 st optical circulator 121, a 2 nd optical circulator 122, a 1 st optical system 131, a 2 nd optical system 132, a 1 st combining unit 153, a 2 nd combining unit 154, a 1 st spectroscopic unit 155, a 2 nd spectroscopic unit 156, a 1 st photoelectric conversion unit 161a, a 2 nd photoelectric conversion unit 162a, a 1 st digital conversion unit 171a, a 2 nd digital conversion unit 172a, a frequency measuring unit 181a, a distance calculating unit 182a, and an information transmitting unit 190.

In the configuration of the optical distance measuring apparatus 100a, the same components as those of the optical distance measuring apparatus 100 are denoted by the same reference numerals, and redundant description thereof is omitted. That is, the description of the structure of fig. 7 to which the same reference numerals as those described in fig. 1 are given is omitted.

The laser light source 101a emits laser light as continuous light. In embodiment 2, the laser light source 101a is a light source that emits laser light having a plurality of frequencies, and is configured by an ASE (Amplified Spontaneous Emission) light source or the like.

The laser light source 101a is not necessarily configured in the optical distance measuring apparatus 100a according to embodiment 2. For example, the optical distance measuring device 100a may operate by receiving laser light emitted from an external laser light generating device having the laser light source 101 a.

The branching portion 103a is configured by an optical coupler or the like, branches the input continuous wave laser light, and outputs the branched laser light as measurement light and reference light. More specifically, the branching unit 103a branches the laser light having a plurality of frequencies emitted from the laser light source 101a, and outputs the branched laser light as the measurement light and the reference light.

The optical distance measuring device 100a according to embodiment 2 includes a laser light source 101a, a branching unit 103a, a measurement optical branching unit 104, a reference optical branching unit 105, a delay adjustment unit 106, a 1 st optical circulator 121, a 2 nd optical circulator 122, a 1 st optical system 131, and a 2 nd optical system 132, and constitutes a transmission unit 110 a.

The 1 st combining unit 153 is configured by an optical coupler or the like, combines the 1 st reference light and the 1 st reflected light, and outputs the combined 1 st reference light and 1 st reflected light as 1 st combined light.

The 1 st spectroscopic unit 155 is configured by a diffraction grating or the like, spatially spectrally separates the 1 st combined light output from the 1 st combining unit 153, and irradiates the 1 st combined light after spectral separation as the 1 st spectrally separated light.

The 1 st photoelectric conversion unit 161a has photoelectric elements arranged in an array, receives the 1 st spectrally separated light irradiated from the 1 st spectroscopic unit 155, and outputs a 1 st analog signal in which information indicating the intensity of the 1 st combined light is associated with the position of each of the photoelectric elements arranged in an array.

The 1 st digital converter 171a performs a/D conversion on the 1 st analog signal, and outputs the 1 st analog signal after the a/D conversion as a 1 st reception signal, the 1 st reception signal being a digital signal.

The optical distance measuring apparatus 100a according to embodiment 2 includes a 1 st receiving unit 141a including a 1 st combining unit 153, a 1 st spectroscopic unit 155, a 1 st photoelectric conversion unit 161a, and a 1 st digital conversion unit 171 a.

That is, the 1 st receiving unit 141a receives the 1 st reflected light that is the light of the 1 st reference light and the 1 st measurement light reflected by the object 20, and outputs the 1 st received signal indicating the 1 st reference light and the 1 st reflected light.

The 2 nd combining unit 154 is configured by an optical coupler or the like, combines the 2 nd reference light and the 2 nd reflected light, and outputs the combined 2 nd reference light and the 2 nd reflected light as the 2 nd combined light.

The 2 nd splitting unit 156 is configured by a diffraction grating or the like, spatially spectrally separates the 2 nd combined light output from the 2 nd combining unit 154, and irradiates the spectrally separated 2 nd combined light as the 2 nd spectrally separated light.

The 2 nd photoelectric conversion unit 162a has photoelectric elements arranged in an array, receives the 2 nd spectrally separated light irradiated from the 2 nd spectroscopic unit 156, and outputs a 2 nd analog signal in which information indicating the intensity of the 2 nd combined light is associated with the position of each of the photoelectric elements arranged in an array.

The 2 nd digital converter 172 a/D converts the 2 nd analog signal, and outputs the a/D converted 2 nd analog signal as a 2 nd reception signal, where the 2 nd reception signal is a digital signal.

The optical distance measuring apparatus 100a according to embodiment 2 includes a 2 nd receiving unit 142a including a 2 nd combining unit 154, a 2 nd spectroscopic unit 156, a 2 nd photoelectric conversion unit 162a, and a 2 nd digital conversion unit 172 a.

That is, the 2 nd receiving unit 142a receives the 2 nd reflected light, which is the light obtained by reflecting the 2 nd reference light and the 2 nd measurement light on the object 20, and outputs the 2 nd received signal indicating the 2 nd reference light and the 2 nd reflected light.

The frequency measuring unit 181a measures the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on the 1 st received signal. The frequency measuring unit 181a outputs 1 st signal information indicating the measured intensity of each frequency component of the 1 st reference light and the 1 st reflected light.

The frequency measuring unit 181a measures the intensity of each frequency component of the 2 nd reference light and the 2 nd reflected light based on the 2 nd reception signal. The frequency measuring unit 181a outputs the 2 nd signal information indicating the measured intensity of each frequency component of the 2 nd reference light and the 2 nd reflected light.

More specifically, for example, the frequency measuring unit 181a measures the intensity of each frequency component of the 1 st reference light and the 1 st reflected light based on information in which the frequency is associated with the position of each of the arrayed photoelectric elements in the 1 st photoelectric conversion unit 161a and information indicating the intensity of the 1 st combined light in the 1 st received signal associated with the position of each of the arrayed photoelectric elements. In addition, it is assumed that information in the 1 st photoelectric conversion portion 161a, which associates a frequency with the position of each photoelectric element arranged in an array, is known. Similarly, the frequency measuring unit 181a measures the intensity of each frequency component of the 2 nd reference light and the 2 nd reflected light based on information in which the frequency is associated with the position of each of the photoelectric elements arranged in an array in the 2 nd photoelectric conversion unit 162a and information indicating the intensity of the 2 nd synthesized light corresponding to the position of each of the photoelectric elements arranged in an array in the 2 nd received signal. In addition, it is assumed that information in the 2 nd photoelectric conversion portion 162a, which associates a frequency with the position of each photoelectric element arranged in an array, is known.

The distance calculation unit 182a calculates the distance from the transmission unit 110a to the object 20 based on the 1 st signal information or the 2 nd signal information output from the frequency measurement unit 181 a. The distance calculation unit 182a outputs distance information indicating the calculated distance from the transmission unit 110a to the object 20.

More specifically, the distance calculating unit 182a calculates the distance from the transmitting unit 110a to the object 20 based on the 1 st signal information or the 2 nd signal information by the same method as that based on the spectral domain type optical interference tomograph which is a known technique. Since a distance measuring method using a spectral domain optical interference tomographic apparatus is well known, a description thereof will be omitted.

As described above, the optical distance measuring apparatus 100a includes: a transmission unit 110a having a branching unit 103a, a measurement light branching unit 104, a reference light branching unit 105, a 1 st optical system 131 and a 2 nd optical system 132, wherein the branching unit 103a branches an input continuous wave laser beam having a plurality of frequencies, outputs the branched laser beam as measurement light and reference light, the measurement light branching unit 104 branches the measurement light output from the branching unit 103a, outputs the branched measurement light as 1 st measurement light and 2 nd measurement light, the reference light branching unit 105 branches the reference light output from the branching unit 103a, and outputs the branched reference light as 1 st reference light and 2 nd reference light, the 1 st optical system 131 has a 1 st rayleigh length and irradiates the 1 st measurement light on the object 20, and the 2 nd optical system 132 has a 2 nd rayleigh length different from the 1 st rayleigh length and has a focal length equal to a focal length of the 1 st optical system 131, for irradiating the object 20 with the 2 nd measurement light; a 1 st receiving unit 141a that receives 1 st reflected light that is light obtained by reflecting the 1 st reference light and the 1 st measurement light on the object 20 and outputs a 1 st received signal indicating the 1 st reference light and the 1 st reflected light; and a 2 nd receiving unit 142a that receives 2 nd reflected light that is light obtained by reflecting the 2 nd reference light and the 2 nd measurement light on the object 20 and outputs a 2 nd reception signal indicating the 2 nd reference light and the 2 nd reflected light, the 1 st receiving unit 141a including: a 1 st combining unit 153 that combines the 1 st reference light and the 1 st reflected light and outputs the combined 1 st reference light and 1 st reflected light as 1 st combined light; a 1 st spectroscopic unit 155 that spatially spectrally separates the 1 st combined light output from the 1 st combining unit 153 and irradiates the 1 st combined light after spectral separation as 1 st spectrally separated light; and a 1 st photoelectric conversion unit 161a which has photoelectric elements arranged in an array, receives the 1 st spectrally separated light irradiated from the 1 st spectroscopic unit 155, and outputs information indicating the intensity of the 1 st combined light as a 1 st reception signal in association with the position of each of the photoelectric elements arranged in an array, and the 2 nd reception unit 142a has: a 2 nd combining unit 154 that combines the 2 nd reference light and the 2 nd reflected light and outputs the combined 2 nd reference light and the 2 nd reflected light as a 2 nd combined light; a 2 nd spectroscopic unit 156 that spatially spectrally separates the 2 nd synthesized light output from the 2 nd synthesizing unit 154 and irradiates the 2 nd synthesized light after spectral separation as 2 nd spectrally separated light; and a 2 nd photoelectric conversion unit 162a having photoelectric elements arranged in an array, receiving the 2 nd spectrally separated light irradiated from the 2 nd spectroscopic unit 156, and outputting information indicating the intensity of the 2 nd combined light as a 2 nd reception signal in association with the position of each of the photoelectric elements arranged in an array.

With this configuration, the optical distance measuring apparatus 100a can extend the range of measuring the distance from the transmission unit 110a to the object 20, and can measure the distance with high accuracy.

The present invention can freely combine the respective embodiments, change arbitrary components of the respective embodiments, or omit arbitrary components of the respective embodiments within the scope of the present invention.

Industrial applicability

The optical distance measuring device of the present invention can be applied to a processing device.

Description of the reference symbols

10 processing device, 11 chuck, 12 processing head, 13 processing head movement control section, 14 processing head movement mechanism, 15 chuck movement control section, 16 chuck movement mechanism, 20 object, 100a optical distance measuring device, 101 laser light source, 101a broadband laser light source, 102 scanning section, 103a branching section, 104 measuring light branching section, 105 reference light branching section, 106 delay adjusting section, 110a transmitting section, 121 1 st optical circulator, 122 nd 2 optical circulator, 131 st 1 optical system, 132 nd 2 optical system, 141a 1 st receiving section, 142a 2 nd receiving section, 151 th 1 st optical interference section, 152 nd 2 optical interference section, 153 th 1 combining section, 154 nd 2 combining section, 155 th 1 spectroscopic section, 156 nd spectroscopic section, 161a 1 st photoelectric conversion section, 162a 2 nd photoelectric conversion section, 171a 1 st digital conversion section, 172. 172a 2 nd digital converter, 181 and 181a frequency measuring units, 182 and 182a distance calculating unit, and 190 information transmitting unit.