JPH0255755B2 - - Google Patents
Info
- Publication number
- JPH0255755B2 JPH0255755B2 JP54159467A JP15946779A JPH0255755B2 JP H0255755 B2 JPH0255755 B2 JP H0255755B2 JP 54159467 A JP54159467 A JP 54159467A JP 15946779 A JP15946779 A JP 15946779A JP H0255755 B2 JPH0255755 B2 JP H0255755B2
- Authority
- JP
- Japan
- Prior art keywords
- optical path
- light
- intensity
- frequency
- phase difference
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000003287 optical effect Effects 0.000 claims description 65
- 230000010287 polarization Effects 0.000 claims description 31
- 238000005259 measurement Methods 0.000 claims description 29
- 238000006243 chemical reaction Methods 0.000 claims description 20
- 238000000926 separation method Methods 0.000 claims description 16
- 238000001514 detection method Methods 0.000 claims description 10
- 230000004907 flux Effects 0.000 claims description 6
- 230000009977 dual effect Effects 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 9
- 241000282326 Felis catus Species 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000011521 glass Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/32—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
- G01S17/36—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated with phase comparison between the received signal and the contemporaneously transmitted signal
Description
【発明の詳細な説明】
(技術分野)
本発明は、光波の速度を利用して遠方に置かれ
た反射体等までの距離を測定する距離測定装置に
関する。DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a distance measuring device that uses the speed of light waves to measure the distance to a reflector placed far away.
(発明の背景)
寸法(距離)を正確に、人手を省いて測定した
いという要求は大きい。(Background of the Invention) There is a strong demand for measuring dimensions (distances) accurately and without manpower.
従来正確な測長法として小さな寸法に対しては
光波干渉計が知られている。 Conventionally, a light wave interferometer is known as an accurate length measurement method for small dimensions.
長い寸法に対しては三角測量が知られているが
多くの人手を必要とする。 Triangulation is known for long dimensions, but requires a lot of manpower.
そこで光を強度変調し、変調波の波長を単位と
して三角測量にかわる測定を行う装置が開発され
ている。 Therefore, a device has been developed that modulates the intensity of light and performs measurement in place of triangulation using the wavelength of the modulated wave as a unit.
このような装置で、変調周波数が30MHzのとき
変調波の波長は10mとなり、数10m程度の中程度
の長さ測定には充分な精度が得がたい。変調周波
数を500MHz程度に高めた装置も発表されている。
しかしこのような高い周波数で光を変調すること
は必ずしも容易ではない。 With such a device, when the modulation frequency is 30 MHz, the wavelength of the modulated wave is 10 m, making it difficult to obtain sufficient accuracy for measuring medium lengths of several tens of meters. Devices with a modulation frequency raised to around 500MHz have also been announced.
However, modulating light at such high frequencies is not always easy.
(発明の目的)
本発明の目的は、簡単な装置で中程度の距離を
高精度に測定することができる距離測定装置を提
供することにある。(Objective of the Invention) An object of the present invention is to provide a distance measuring device that can measure medium distances with high precision using a simple device.
(発明の構成)
前記目的を達成するために、本発明による二周
波直交偏光測距装置は、近接した異なる周波数の
二つの直交偏光を発振するレーザ光源と、前記光
源からの光束を分離し夫々を前記周波数差で強度
変調する分離変調手段と、既知の基準光路を通過
した前記一方の光束を光電変換し、前記差の周波
数の信号を得る第1の光電変換手段と、測定光路
を通過した前記他方の光束を光電変換し、前記差
の周波数の信号を得る第2の光電変換手段と、前
記第1および第2の光電変換手段の出力間の位相
差を検出する位相差検出手段とを含み、前記信号
間の位相差により測定光路長と基準光路長の差を
知ることにより測定光路長を測定するように構成
されている。(Structure of the Invention) In order to achieve the above object, a dual-frequency orthogonal polarization ranging device according to the present invention includes a laser light source that oscillates two orthogonally polarized lights of adjacent different frequencies, and a laser light source that separates the light beams from the light source, respectively. a first photoelectric conversion means for photoelectrically converting one of the light beams that has passed through the known reference optical path to obtain a signal at the frequency of the difference; a second photoelectric conversion means for photoelectrically converting the other luminous flux to obtain a signal of the difference frequency; and a phase difference detection means for detecting a phase difference between the outputs of the first and second photoelectric conversion means. and is configured to measure the measurement optical path length by determining the difference between the measurement optical path length and the reference optical path length from the phase difference between the signals.
(実施例の説明)
以下、図面等を参照して本発明をさらに詳しく
説明する。(Description of Examples) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.
レーザ媒質の利得巾と共振器間隔が適当な関係
にある共振器間隔30cm程度のHe−Ne内部鏡レー
ザ発振器は477THz近辺で500MHzの周波数差をも
つ二つの縦モードで安定に発振させることができ
る。 A He-Ne internal mirror laser oscillator with a cavity spacing of about 30 cm, in which the gain width of the laser medium and the cavity spacing have an appropriate relationship, can stably oscillate in two longitudinal modes with a frequency difference of 500 MHz around 477 THz. .
この二つの縦モードの光は通常互に直交した直
線偏光となつている。 These two longitudinal modes of light are normally linearly polarized light that is orthogonal to each other.
したがつて、これらの位相関係を、偏光光学的
な補償素子を用いて調整することができ、必要に
応じ二つの成分光を直線偏光子を通すことにより
干渉させることができ、光周波数の差周波数で強
度変調された光に変換することができる。 Therefore, these phase relationships can be adjusted using a polarization optical compensation element, and if necessary, two component lights can be caused to interfere by passing through a linear polarizer, and the difference in optical frequency can be adjusted. It can be converted into frequency- and intensity-modulated light.
本発明は二周波直交偏光のこの特徴を積極的に
利用している。 The present invention actively exploits this feature of dual-frequency orthogonal polarization.
第2図は、本発明による二周波直交偏光測距装
置の光路例および基本構成例を示すブロツク図で
ある。 FIG. 2 is a block diagram showing an example of the optical path and basic configuration of a dual-frequency orthogonal polarization distance measuring device according to the present invention.
レーザ光源(STLM)1は近接した異なる周
波数の二つの直交偏光を発振することができる。
変調手段2は分離要素2aと前記分離要素2aに
より分離された光源1からの光束を、それぞれ前
記周波数差で強度変調する変調手段2b,2cに
より構成されている。 A laser light source (STLM) 1 can oscillate two orthogonally polarized lights with different frequencies that are close to each other.
The modulating means 2 is constituted by a separating element 2a and modulating means 2b and 2c which respectively intensity-modulate the luminous flux from the light source 1 separated by the separating element 2a using the frequency difference.
既知の基準光路は前記分離手段2aから反射面
10間に形成されている。説明のために以下この
光路長をl1とする。 A known reference optical path is formed between the separating means 2a and the reflecting surface 10. For the sake of explanation, this optical path length will be referred to as l 1 below.
測定光路は前記分離要素2aから反射面11ま
での光路であり、説明のために以下この光路長を
l2とする。 The measurement optical path is the optical path from the separating element 2a to the reflecting surface 11, and for the sake of explanation, this optical path length will be described below.
Let it be l 2 .
なお第2図に示すブロツク図では光路の理解を
容易にするために分離変調手段を分離要素2aと
変調要素2b,2cに分けて説明している。 In the block diagram shown in FIG. 2, the separation and modulation means is explained separately into a separation element 2a and modulation elements 2b and 2c in order to facilitate understanding of the optical path.
しかしながら後述する実施例においてはレーザ
光源1からの光束を分離する際に基準光路の光束
は分離と同時に強度変調される。 However, in the embodiment described later, when the light beam from the laser light source 1 is separated, the light beam on the reference optical path is intensity-modulated at the same time as the separation.
一方測定光路の光速は分離された後に強度変調
を受ける。 On the other hand, the light velocity in the measurement optical path undergoes intensity modulation after being separated.
このような場合に基準光路の光束に着目すると
分離要素2aと変調要素2bは一体であり要素と
して物理的に分離不能である。 In such a case, when focusing on the light beam of the reference optical path, the separation element 2a and the modulation element 2b are integrated and cannot be physically separated as elements.
また測定光路に関しては分離要素2aと変調要
素2cは別の要素となる。 Furthermore, regarding the measurement optical path, the separation element 2a and the modulation element 2c are separate elements.
この場合、また逆の場合においても前記基準光
路長l1および測定光路l2の開始端は分離要素2a
の表面からである。 In this case, and vice versa, the reference optical path length l 1 and the starting end of the measuring optical path l 2 are separated by the separating element 2a.
from the surface.
第1の光電変換手段5は前記既知の基準光路
(2a→2b→10→5)を通過した前記一方の
光束は光電変換し、前記差の周波数の信号を得
る。 The first photoelectric conversion means 5 photoelectrically converts the one luminous flux that has passed through the known reference optical path (2a→2b→10→5) to obtain a signal of the frequency of the difference.
第2の光電変換手段6は測定光路(2a→2c
→11→6)を通過した前記他方の光束を光電変
換し、前記差の周波数の信号を得る。 The second photoelectric conversion means 6 has a measurement optical path (2a→2c
→11→6) The other luminous flux that has passed through is subjected to photoelectric conversion to obtain a signal with the frequency of the difference.
位相差検出手段7は前記第1および第2の光電
変換手段5,6の出力が接続線8,9を介して接
続されており、出力間の位相差を検出する。 The phase difference detection means 7 is connected to the outputs of the first and second photoelectric conversion means 5 and 6 via connection lines 8 and 9, and detects the phase difference between the outputs.
詳細な実施例の説明の前に、この明細書で使用
する用語を定義する。 Before describing detailed embodiments, terms used in this specification will be defined.
直交偏光とは、偏光状態の極性右まわりか左ま
わりかが逆で、だ円主軸が直交し、だ円率が等し
い一対の偏光をさす(第1図参照)。この代表的
な例として、互に直交した直線偏光の対と左右円
偏光の対とがある。 Orthogonally polarized light refers to a pair of polarized lights whose polarization states are opposite in polarity (clockwise or counterclockwise), the principal axes of the ellipses are orthogonal, and the ellipticity is equal (see Figure 1). Typical examples include a pair of linearly polarized lights that are perpendicular to each other and a pair of left and right circularly polarized lights.
直交偏光光源とは、前記直交偏光発振する光源
を指す。ある状態におけるレーザは直交偏光光源
である。 The orthogonally polarized light source refers to the light source that oscillates orthogonally polarized light. A laser in one state is an orthogonally polarized light source.
また直交偏光の位相差を変化させる位相子と
は、直交直線偏光成分に対するソレイユバビネ補
償子SBC、電気光学効果を利用したポツケルス
セル応力複屈折素子等の他、左右円偏光成分の位
相差を変化させる旋光子、フアラデー効果素子等
を含む。 In addition, retarders that change the phase difference of orthogonally polarized light include a Soleil Babinet compensator SBC for orthogonal linearly polarized light components, a Pockels cell stress birefringence element that uses the electro-optic effect, and a retarder that changes the phase difference of left and right circularly polarized light components. Includes optical rotators, Faraday effect elements, etc.
第3図は本発明による、二周波直交偏光を利用
した測距装置の第1の実施例を示すブロツク図で
ある。 FIG. 3 is a block diagram showing a first embodiment of a distance measuring device using two-frequency orthogonal polarized light according to the present invention.
レーザ光源(STML)1は周波数の差が500M
Hz程度の互に直交した偏りをもつ二つの縦モード
を安定して発振することができるレーザ光源であ
る。 Laser light source (STML) 1 has a frequency difference of 500M
This is a laser light source that can stably oscillate two longitudinal modes with mutually orthogonal polarization on the order of Hz.
理解を容易にするために、二つの発振光成分は
±45°の直線偏光であるとして説明する。 For ease of understanding, the explanation will be given assuming that the two oscillation light components are linearly polarized light of ±45°.
この状態は、左右円偏光を発振するレーザ光源
の光を、主軸方向0°の1/4波長板を通すことによ
つても得ることができる。 This state can also be obtained by passing the light from a laser light source that oscillates left-right circularly polarized light through a quarter-wave plate with a principal axis direction of 0°.
レーザ光源(STML)1の出力は、分離変調
手段2により分離され強度変調されて基準光路
と、測定光路に送出される。 The output of the laser light source (STML) 1 is separated and intensity-modulated by a separation modulation means 2 and sent to a reference optical path and a measurement optical path.
分離変調手段2はブリユースター反射面BR0゜、
第2のブリユースター反射面BR90゜、および他の
反射面2dから構成されている。 Separation modulation means 2 is a Brewstar reflecting surface BR0°,
It is composed of a second Brew Star reflective surface BR90° and another reflective surface 2d.
ブリユースター反射面BR0゜は方位0゜の直線偏
光成分を部分的に反射する。反射により分離され
強度変調を受けた基準光路の光束は、前記他の反
射器2dで径路を変更されて送出される。 The Brew Star reflective surface BR0° partially reflects the linearly polarized light component with an orientation of 0°. The light beam on the reference optical path, which has been separated by reflection and subjected to intensity modulation, is route-changed by the other reflector 2d and then sent out.
このブリユースター反射器BR0゜の透過光の偏
光状態を入射状態に保つよう、90゜の直線偏光成
分を部分的に反射する第2のブリユースター反射
器BR90゜を組合せて使用する。 In order to maintain the polarization state of the light transmitted through this Brewstar reflector BR0° in the incident state, a second Brewstar reflector BR90° that partially reflects the 90° linearly polarized light component is used in combination.
ブリユースター反射器BR0゜で反射された光は
基準光路を通り、基準光路の終点に位置するキヤ
ツツアイ反射器CE1で反射されて第1の光電変
換手段である光ダイオードPh1で光電変換され
る。 The light reflected by the Brew Star reflector BR0° passes through the reference optical path, is reflected by the cat's eye reflector CE1 located at the end point of the reference optical path, and is photoelectrically converted by the photodiode Ph1, which is the first photoelectric conversion means.
偏光素子P0゜(90゜)は、ブリユースター反射器
BR0゜およびBR90゜を直進した光を方位0゜または
90゜に強度変調する。 Polarizing element P0° (90°) is a Brewster reflector
The light that went straight through BR0° and BR90° is set to 0° or
The intensity is modulated at 90°.
測定光路に送りこまれたレーザ光は測定光路の
終端の反射器CE2で反射され、第2の光電変換手
段である光ダイオードPh2に集光されて光電変換
される。 The laser beam sent into the measurement optical path is reflected by a reflector CE 2 at the end of the measurement optical path, and is focused on a photodiode Ph 2 , which is a second photoelectric conversion means, for photoelectric conversion.
レーザ光源(STML)1の共振器間隔をL、
二つの縦モードの次数をq、q+1とすると各縦
モード光の波長は2L/q、2L/(q+1)とな
る。したがつて、この二つの光波の相対位相は、
二つの波長の最小公倍長である2Lごとに初めの
状態にもどる。内部鏡型レーザの縦モードは交互
に直交した直線偏光である。 The cavity spacing of laser light source (STML) 1 is L,
If the orders of the two longitudinal modes are q and q+1, the wavelengths of each longitudinal mode light are 2L/q and 2L/(q+1). Therefore, the relative phase of these two light waves is
It returns to the initial state every 2L, which is the least common length of the two wavelengths. The longitudinal modes of an internal mirror laser are alternating orthogonal linear polarizations.
したがつてこれらの合成はだ円偏光となるが、
光の進行に伴つて直交成分の位相差が変化するか
らだ円状態は2Lを周期に場所的に変化する。 Therefore, the combination of these becomes elliptical polarized light,
Since the phase difference of orthogonal components changes as the light travels, the elliptical state changes locally with a period of 2L.
光はこの状態を保つて光速度で進行する。 Light maintains this state and travels at the speed of light.
この二つの直交成分が共存する状態で両者の相
対位相を偏光光学的に変化させれば、空間的な偏
光状態変化が前後に変化する。 If the relative phase of these two orthogonal components is changed in a polarization optical manner in a state where they coexist, the spatial polarization state changes back and forth.
ここで合成光を直線偏光子に通せば、空間的偏
光状態の変化は、光速度で進行する空間的に強度
変調された直線偏光となる。 If the combined light is passed through a linear polarizer, the spatial polarization state changes to spatially intensity-modulated linear polarized light that travels at the speed of light.
この強度変調波の波長は2L、この光を光電変
換した信号の周波数はC/2L(C:光速度)とな
る。 The wavelength of this intensity modulated wave is 2L, and the frequency of the signal obtained by photoelectrically converting this light is C/2L (C: speed of light).
この値はL=0.3mのばあい500MHzである。 This value is 500MHz when L=0.3m.
ブリユースター反射器BR0゜から反射器CE1,
CE2までの距離l1,l2、空気の屈曲率を1とし、
標準・測定両光束とも往複の光路長が等しいと考
えると、BR0゜から光ダイオードPh1,Ph2までの
光路長は夫々2l1、2l2となる。そして各光ダイオ
ードPh1,Ph2で光電変換される光電信号は、
BR0゜面における強度変調の変化に対して夫々
2l1/2L、2l2/2Lだけ進んでいる。 Brewstar reflector BR0° to reflector CE 1 ,
The distance to CE 2 is l 1 , l 2 , the air curvature is 1,
Considering that the optical path lengths of both the standard and measurement beams are equal, the optical path lengths from BR0° to the photodiodes Ph 1 and Ph 2 are 2l 1 and 2l 2 , respectively. The photoelectric signals photoelectrically converted by each photodiode Ph 1 and Ph 2 are
For changes in intensity modulation on the BR0゜ plane,
It has advanced by 2l 1 /2L and 2l 2 /2L.
したがつてこれら二つの変調信号の位相差は
式のように求められる。 Therefore, the phase difference between these two modulation signals can be obtained as shown in the equation.
(l2−l1)/L=N+p ………
但しNは位相差の整数部、pは端数部である。
このpを位相差検出手段7を形成する二現象オシ
ロスコープまたは位相計により実測し、Nを(l2
−l1)の概略値とLから決定すれば、l2は式の
ように求められる。 (l 2 −l 1 )/L=N+p where N is the integer part of the phase difference and p is the fractional part.
This p is actually measured using a two-phenomenon oscilloscope or a phase meter forming the phase difference detection means 7, and N is (l 2
−l 1 ) and L, l 2 can be obtained as shown in the formula.
l2=l1+NL+pL ………
第3図に示されているように、基準光路と測定
光路に光束を分離するのに、一つの直線偏光成分
だけを一部反射し他を透過させる素子、例えば入
射角をブリユースター角に保つた硝子板を用いる
と、独立の偏光子を用いることなく、反射光を振
巾変調できる。 l 2 = l 1 + NL + pL ...... As shown in Figure 3, in order to separate the light beam into the reference optical path and the measurement optical path, an element that partially reflects only one linearly polarized component and transmits the other, For example, by using a glass plate that maintains the incident angle at the Brewster angle, the amplitude of the reflected light can be modulated without using an independent polarizer.
今、オシロスコープあるいは、二つの光電信号
の位相関係を検出する位相差検出手段7を監視し
つつ基準光路の長さl1を調節し位相関係を同相p
=0(あるいは逆相p=±1/2に設立すれば
式の関係を成立させることができる。 Now, while monitoring the oscilloscope or the phase difference detection means 7 that detects the phase relationship between the two photoelectric signals, adjust the length of the reference optical path l1 to make the phase relationship in-phase p.
= 0 (or by establishing the opposite phase p = ±1/2, the relationship of the formula can be established.
l2=l1+NL
または
l2=l1+(N+1/2)L ………
基準光路の長さl1の調節は光電変換手段である
光ダイオードPh1を移動させることなく、反射鏡
CE1の位置を調整することにより、可能である。 l 2 = l 1 + NL or l 2 = l 1 + (N + 1/2) L ...... The length of the reference optical path l 1 can be adjusted without moving the photodiode Ph 1 , which is the photoelectric conversion means.
It is possible by adjusting the position of CE 1 .
測定光路l2の調整によつても同様な関係を成立
させることができる。 A similar relationship can be established by adjusting the measurement optical path l2 .
第4図は本発明による二周波直交偏光測距装置
の他の実施例を示す図である。 FIG. 4 is a diagram showing another embodiment of the dual-frequency orthogonal polarization distance measuring device according to the present invention.
分離変調手段2の偏光子BR0゜,BR90゜の後に
直交偏光の位相差をΔだけ変化させる素子(例え
ば方位45゜のソレイユバビネ補償子SBC)を挿入
すれば、BR0゜,BR90゜を通つて強度変調された
光の角位相もΔだけ変化する。 If an element that changes the phase difference of orthogonally polarized light by Δ is inserted after the polarizers BR0° and BR90° of the separation modulation means 2 (for example, a Soleil-Babinet compensator SBC with an orientation of 45°), the light will pass through the polarizers BR0° and BR90°. The angular phase of the intensity modulated light also changes by Δ.
このようにして、偏光補償子SBCでリターデ
イシヨン調節を行い二つの光電信号の位相差を合
致させ、偏光補償量から位相差の端数pの測定を
行うことができる。 In this way, the retardation is adjusted by the polarization compensator SBC to match the phase difference between the two photoelectric signals, and the fraction p of the phase difference can be measured from the amount of polarization compensation.
第5図は本発明による二周波直交偏光測距装置
のさらに他の実施例を示す図である。 FIG. 5 is a diagram showing still another embodiment of the dual-frequency orthogonal polarization distance measuring device according to the present invention.
測定光路BR0゜,BR90゜の後に方位0゜の1/4波長
板Q0゜を挿入すると、これを通過した光の偏光状
態は直線偏光方位の回転となる。第5図のように
偏光子を方位の調節できる直線偏光子Pθとし、
この方位を回転させて信号位相子の端数の測定を
行うことができる。 If a quarter-wave plate Q0° with an orientation of 0° is inserted after the measurement optical paths BR0° and BR90°, the polarization state of the light that passes through it will be a rotation of the linear polarization orientation. As shown in Figure 5, the polarizer is a linear polarizer Pθ whose orientation can be adjusted,
By rotating this orientation, it is possible to measure the fraction of the signal phase shifter.
このとき信号位相差の端数pと、偏光子の回転
角αの間にはα=πpの関係がある。 At this time, there is a relationship α=πp between the fraction p of the signal phase difference and the rotation angle α of the polarizer.
第1図のP0゜(90゜)の方位が0゜の場合と90゜の場
合では、測定光路の強度変調の位相が逆になる。 When the orientation of P0° (90°) in FIG. 1 is 0° and 90°, the phase of the intensity modulation of the measurement optical path is opposite.
基準光路1と測定光路2の光電信号の位相差が
±π/2のときには、基準光路1の信号で測定光
路2の信号を同期検波すると検波出力は、測定光
路2の信号の位相が反転しても変化しない。 When the phase difference between the photoelectric signals of the reference optical path 1 and the measurement optical path 2 is ±π/2, when the signal of the measurement optical path 2 is synchronously detected with the signal of the reference optical path 1, the detection output is such that the phase of the signal of the measurement optical path 2 is reversed. It doesn't change even though.
したがつて、P0゜(90゜)のかわりに連続回転す
る偏光子を用い、同期検波の回転に同期した変化
がなくなるよう基準光路の長さを調節して、位相
直交の設定を行い距離測定を正確に行うことがで
きる。 Therefore, a continuously rotating polarizer is used instead of P0° (90°), the length of the reference optical path is adjusted so that there is no change in synchronization with the rotation of the synchronous detection, and the phase quadrature is set to perform distance measurement. can be done accurately.
この測定は、P0゜(90゜)を方位回転させるかわ
りに、BR0゜とP0゜(90゜)の間に直交直線偏光成分
の位相差を動的に変化させる素子、例えばポツケ
ルス素子を置いてリターデイシヨンを正負に振動
的に変調させても行なえる。この方法により、偏
光子を機械的に回転させる必要がなくなる。 In this measurement, instead of rotating P0° (90°), an element that dynamically changes the phase difference of orthogonal linearly polarized light components, such as a Pockels element, is placed between BR0° and P0° (90°). This can also be done by vibrationally modulating the retardation in positive and negative directions. This method eliminates the need to mechanically rotate the polarizer.
(発明の効果)
本発明により簡単な装置で光強度を500MHz以
上の超高周波で変調し、長い距離を電気信号の位
相を測定するか、光路長を光学的に補償し、ある
いは二つの直交偏光成分の位相差を偏光光学的に
補償して高い精度を測定できる。(Effect of the invention) The present invention modulates the optical intensity with a super high frequency of 500 MHz or more using a simple device, measures the phase of an electrical signal over a long distance, optically compensates the optical path length, or generates two orthogonal polarized lights. It is possible to measure with high accuracy by compensating for the phase difference of the components using polarization optics.
レーザ光源としてレーザ共振器間隔L=0.26m
のHe−Ne内部鏡レーザを用い、ソレイユバビネ
補償子で補償測定する方法により、測定用反射器
までの距離7m(=l2)において繰返し、測定値
の標準偏光0.6mmが得られた。 Laser cavity spacing L = 0.26m as a laser light source
By using a He--Ne internal mirror laser and compensating measurement with a Soleil Babinet compensator, a standard polarization value of 0.6 mm was repeatedly obtained at a distance of 7 m (=l 2 ) to the measuring reflector.
測定値の綜合的変動はこの変差とレーザ共振器
間隔Lの変動に基づく測定値変動の和となる。 The total variation of the measured value is the sum of this variation and the measured value variation due to the variation of the laser resonator spacing L.
レーザ共振器間隔Lの変動を半波長の1/10と止
めることは容易であるから、このときの共振器長
の変動による測定値変動は0.7μにすぎない。 Since it is easy to limit the variation in the laser resonator spacing L to 1/10 of a half wavelength, the measurement value variation due to the variation in the resonator length at this time is only 0.7μ.
第1図は直交偏光という用語を説明するための
グラフである。第2図は本発明による二周波直交
偏光測距装置の光路例および基本的構成例を示す
ブロツク図である。第3図は本発明による二周波
直交偏光測距装置の実施例を示すブロツク図であ
る。第4図は本発明による二周波直交偏光測距装
置の他の実施例を示すブロツク図である。第5図
は本発明による二周波直交偏光測距装置のさらに
他の実施例を示すブロツク図である。
1……レーザ光源(STLM)、2……分離変調
手段、5……第1の光電変換手段、6……第2の
光電変換手段、7……位相差検出手段、8,9…
…接続線、10……基準光路終端の反射面、11
……測定光路終端の反射面、BR0゜……方位0゜の
直線偏光を部分的に反射するブリユースター反射
器、BR90゜……方位90゜の直線偏光を部分的に反
射するブリユースター反射器、P0゜……0゜の方位
を主軸とする偏光子、P90゜……90゜の方位を主軸
とする偏光子、Pθ……θ゜の方位を主軸とする偏光
子(θは連続可変)、CE1……基準光路終端のキ
ヤツツアイ反射器、CE2……測定光路終端のキヤ
ツツアイ反射器、Ph1……第1の光電変換手段を
形成する光ダイオード、Ph2……第2の光電変換
手段を形成する光ダイオード、SBC……ソレイ
ユバビネ補償子、Q……1/4波長板。
FIG. 1 is a graph for explaining the term orthogonal polarization. FIG. 2 is a block diagram showing an example of an optical path and a basic configuration of a dual-frequency orthogonal polarization distance measuring device according to the present invention. FIG. 3 is a block diagram showing an embodiment of a dual frequency orthogonal polarization distance measuring device according to the present invention. FIG. 4 is a block diagram showing another embodiment of the dual frequency orthogonal polarization distance measuring device according to the present invention. FIG. 5 is a block diagram showing still another embodiment of the dual frequency orthogonal polarization distance measuring device according to the present invention. DESCRIPTION OF SYMBOLS 1... Laser light source (STLM), 2... Separation modulation means, 5... First photoelectric conversion means, 6... Second photoelectric conversion means, 7... Phase difference detection means, 8, 9...
... Connection line, 10 ... Reflection surface at the end of the reference optical path, 11
...Reflecting surface at the end of the measurement optical path, BR0゜...Brewster reflector that partially reflects linearly polarized light with an azimuth of 0°, BR90゜...Brewster that partially reflects linearly polarized light with an azimuth of 90° Reflector, polarizer whose principal axis is in the direction of P0゜...0゜, polarizer whose main axis is in the direction of P90゜...90゜, polarizer whose main axis is in the direction of Pθ...θ゜ (θ is continuous variable), CE 1 ... cat's eye reflector at the end of the reference optical path, CE 2 ... cat's eye reflector at the end of the measurement optical path, Ph 1 ... photodiode forming the first photoelectric conversion means, Ph 2 ... the second Photodiode forming the photoelectric conversion means, SBC...Soleil Babinet compensator, Q...1/4 wavelength plate.
Claims (1)
振するレーザ光源と、前記光源からの光束を分離
し夫々を前記周波数差で強度変化する光に変換す
る分離変調手段と、既知の基準光路を通過した前
記一方の光束を光電変換し、前記差の周波数の信
号を得る第1の光電変換手段と、測定光路を通過
した前記他方の光束を光電変換し、前記差の周波
数の信号を得る第2の光電変換手段と、前記第1
および第2の光電変換手段の出力間の位相差を検
出する位相差検出手段とを含み、前記信号間の位
相差により測定光路長と基準光路長の差を知るこ
とにより測定光路長を測定するように構成した二
周波直交偏光側距装置。 2 前記分離変調手段は直交直線偏光の一方を部
分的に反射して光束を分離し、同時に分離された
光を強度変調する偏光素子である特許請求の範囲
1項記載の二周波直交偏光測距装置。 3 基準光路あるいは測定光路の光路長は調節可
能であり、前記位相差検出手段は前記各光電変換
手段の信号の間の位相差を、合致または直交状態
にして検出する特許請求の範囲1項記載の二周波
直交偏光測距装置。 4 前記分離変調手段は光束を分離する分離素子
と、光束を強度変調する偏光子と前記分離素子の
間に挿入された直交した偏光成分の光学的位相差
を補償する偏光光学系からなり、偏光光学補償に
よつて分離され光束間の強度変調の相対位相を補
償する特許請求の範囲1項記載の二周波直交偏光
測距装置。 5 前記光源からの光束を分離し夫々を前記周波
数差で強度変調する分離変調手段は、方位を振動
的に回転させるか連続回転させる直線偏光子を含
み、強度変調の位相反転を利用して、前記位相差
検出手段により強度変調の角位相差がπ/2であ
ることを検出する特許請求の範囲1項記載の二周
波直交偏光測距装置。 6 前記光源からの光束を分離し夫々を前記周波
数差で強度変調する分離変調手段は、光束を分離
する素子と光束を強度変調する直線偏光子の間に
直交直線偏光成分の相対位相を変化させる偏光素
子が設けられており、相対位相差を振動的に変調
して基準光路と測定光路の光束の強度変調か逆相
あるいは同位相であることを検出する特許請求の
範囲第1項記載の二周波直交偏光測距装置。[Scope of Claims] 1. A laser light source that oscillates two orthogonally polarized lights with different frequencies that are close to each other, and a separation modulation means that separates the light flux from the light source and converts each light beam into light whose intensity changes depending on the frequency difference. a first photoelectric conversion means that photoelectrically converts the one luminous flux that has passed through the reference optical path of the reference optical path and obtains a signal of the frequency of the difference; a second photoelectric conversion means for obtaining a signal; and a second photoelectric conversion means for obtaining a signal;
and a phase difference detection means for detecting a phase difference between the outputs of the second photoelectric conversion means, and measures the measurement optical path length by determining the difference between the measurement optical path length and the reference optical path length from the phase difference between the signals. A dual frequency orthogonal polarization side range device configured as follows. 2. The dual-frequency orthogonal polarization distance measurement according to claim 1, wherein the separation modulation means is a polarizing element that partially reflects one of the orthogonal linearly polarized lights to separate the light beams, and at the same time modulates the intensity of the separated light. Device. 3. The optical path length of the reference optical path or the measurement optical path is adjustable, and the phase difference detection means detects the phase difference between the signals of the respective photoelectric conversion means in a coincident or orthogonal state. dual-frequency orthogonal polarization ranging device. 4. The separation modulation means includes a separation element that separates the light beam, a polarizer that modulates the intensity of the light beam, and a polarization optical system that compensates for the optical phase difference of orthogonal polarized light components inserted between the separation element, and 2. The dual-frequency orthogonal polarization distance measuring device according to claim 1, which compensates for the relative phase of intensity modulation between the light beams separated by optical compensation. 5. The separation modulation means that separates the light beams from the light source and modulates the intensity of each beam with the frequency difference includes a linear polarizer that vibrably rotates the orientation or continuously rotates the direction, and utilizes phase inversion of the intensity modulation, 2. The dual-frequency orthogonal polarization distance measuring device according to claim 1, wherein said phase difference detection means detects that the angular phase difference of intensity modulation is π/2. 6 The separation modulation means that separates the light beams from the light source and modulates the intensity of each light beam with the frequency difference changes the relative phase of the orthogonal linearly polarized light components between the element that separates the light beams and the linear polarizer that modulates the intensity of the light beams. 2, which is provided with a polarizing element and detects whether the intensity modulation of the light beams in the reference optical path and the measurement optical path is in opposite phase or in phase by vibrationally modulating the relative phase difference; Frequency orthogonal polarization ranging device.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP15946779A JPS5681467A (en) | 1979-12-07 | 1979-12-07 | Measuring device for distance of two frequency- perpendicularly polarized lights |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP15946779A JPS5681467A (en) | 1979-12-07 | 1979-12-07 | Measuring device for distance of two frequency- perpendicularly polarized lights |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5681467A JPS5681467A (en) | 1981-07-03 |
JPH0255755B2 true JPH0255755B2 (en) | 1990-11-28 |
Family
ID=15694398
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP15946779A Granted JPS5681467A (en) | 1979-12-07 | 1979-12-07 | Measuring device for distance of two frequency- perpendicularly polarized lights |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5681467A (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0789147B2 (en) * | 1988-10-31 | 1995-09-27 | シャープ株式会社 | Distance measuring device |
JPH02124581U (en) * | 1989-03-27 | 1990-10-15 | ||
CN101031817B (en) * | 2004-09-30 | 2011-02-09 | Faro科技有限公司 | Absolute distance meter that measures a moving retroreflector |
DE112018007552B4 (en) * | 2018-06-12 | 2022-03-10 | Mitsubishi Electric Corporation | Optical distance measuring device and processing device |
-
1979
- 1979-12-07 JP JP15946779A patent/JPS5681467A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS5681467A (en) | 1981-07-03 |
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