JPS58135910A - Automatic range controller - Google Patents
Automatic range controllerInfo
- Publication number
- JPS58135910A JPS58135910A JP1933182A JP1933182A JPS58135910A JP S58135910 A JPS58135910 A JP S58135910A JP 1933182 A JP1933182 A JP 1933182A JP 1933182 A JP1933182 A JP 1933182A JP S58135910 A JPS58135910 A JP S58135910A
- Authority
- JP
- Japan
- Prior art keywords
- subtraction
- distance
- light
- output
- measured
- 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.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/026—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by measuring distance between sensor and object
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Measurement Of Optical Distance (AREA)
- Automatic Focus Adjustment (AREA)
Abstract
Description
【発明の詳細な説明】
〔発−の技術分野〕
本発明は、被測定物と基準面とを一定距離に制御する自
動距離合わせ装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an automatic distance adjustment device that controls a distance between an object to be measured and a reference surface to be a constant distance.
近時、半導体ウェーハやマスク等の試料に微細パターン
を形成する技術として、光露光、Ｘ線露光、電子ビーム
露光、その他各種の露光法が開発されているが、このよ
うな分野では試料（被測定物）と対物レンズ主面（基準
面）との距離を高＊＊に定める必要が８る、。被測定物
と・基準面とを一定距離に制御してレンズの焦点合わせ
を行うには、従来被測定物に斜めから光を歯て、その反
射光の位置を２組のアナ冒グ信号を発生する一ジシ雪ン
センサ等で検出している。Recently, light exposure, X-ray exposure, electron beam exposure, and various other exposure methods have been developed as technologies for forming fine patterns on samples such as semiconductor wafers and masks. It is necessary to set the distance between the object to be measured) and the main surface of the objective lens (reference surface) to be high. In order to control the distance between the object to be measured and the reference plane and focus the lens, conventionally, light is directed at the object at an angle and two sets of analog signals are used to determine the position of the reflected light. Any snow that occurs is detected by a sensor, etc.
そして、上記２組のアナログ信号を加算・減算すると共
に、除算器を用いて加算出力で減算出力を正規化し、反
射光の位置、すなわち被測定物と基準面との距離を検出
するようにしていた。Then, the above two sets of analog signals are added and subtracted, and a divider is used to normalize the subtracted output with the addition output to detect the position of the reflected light, that is, the distance between the object to be measured and the reference surface. Ta.
しかしながら、この種の手法にあっては次のような問題
があった。すなわち、被欄★物から反射した反射光の強
さが変化し九場合、その検出位置の１！１ＩＩＬは除算
器の精度により大きく影響される。除算器は非直線−を
利用して構成されているため、温度や構成部品等の影響
を受は易く、その精度を上げること祉極めて国難である
。However, this type of method has the following problems. That is, when the intensity of the light reflected from the object changes, the 1!1IIL of the detected position is greatly affected by the accuracy of the divider. Since the divider is constructed using non-linearity, it is easily affected by temperature, component parts, etc., and increasing its accuracy is an extremely national problem.
この丸め、従来被測定物と基準面とのＩＩｊｉ麟を高精
度に定めることはできなかった。Conventionally, it has not been possible to determine the distance between the object to be measured and the reference plane with high accuracy.
本発明の目的は、除算器を用いることなく被測定物と基
準面との距離を検出することができ、上記距離を高精度
に制御することのできる自動距離合わせ装置を提供する
ことにある。An object of the present invention is to provide an automatic distance adjustment device that can detect the distance between an object to be measured and a reference surface without using a divider, and can control the distance with high precision.
本発明の骨子は、被測定物に斜めに光を当てその反射光
をポノシ嘗ンセンサ等の検出器で検出する際、光の強さ
で検出出力が変化するため、検出出力が一定になるよう
光′の強さをコントロールすることにある。さらに、被
測定物と基準面との距離が所望値と一致した場合に検出
出力が零となるように可変ゲインアンプを調整し、上記
距離のずれ音検出出力の零からの差で求め、この差が零
となるよう駆動回路をコントロールし、前記距離を所望
値に合わせるようにしたことＫある。The gist of the present invention is that when light is applied obliquely to the object to be measured and the reflected light is detected by a detector such as a sensor, the detection output changes depending on the intensity of the light, so the detection output is kept constant. The purpose is to control the intensity of light. Furthermore, the variable gain amplifier is adjusted so that the detection output becomes zero when the distance between the object to be measured and the reference plane matches the desired value, and the difference from the deviation sound detection output at the above distance from zero is calculated. In some cases, the drive circuit is controlled so that the difference becomes zero, and the distance is adjusted to a desired value.
すなわち、本発明は被測定物と基準面との距離を一率距
離に合わせる自動距離合わせ装置において、上記被測定
物に斜めから光を轟てる光照射手段と、この光照射手段
による光をパルス変調するＩｇｌの変調手段と、上記光
照射手段による光を振幅変調する第２の変調手段と、前
記基準面と一対的に移動するよう設けられ前記被測定物
からの反射光を蚊反射光の位置に応じ九２組のアナログ
信号として検出する反射光検出手段と、この反射光検出
手段によｐ得られ危２組の検出出力をそれぞれ増幅する
と共に少なくとも一方は増幅度を可変可能にして増幅す
る増幅手段と、前記第ｌの変調手段と同期させて上記増
幅手段によプ得られた２組の増幅出力をそれぞれ対で積
分する積分手段と、この積分手段により得られた２組の
積分出力の各対の差をそれぞれ演算する第１の減算手段
と、この第１の減算手段により得られ良２組の減算出力
の差を演算するｊｉ２の減算手段と、この＃Ｉ２の減算
手段による減算出力が零になるよう前記被測定物或いは
基準面を移動しこれらの距離を可変する移動手段と、前
記第１の減算手段による２組０減算出力の和を演算する
加算手段と、この加算手段による加算出力が一定となる
よう前記第２の変調手段の変調度を制御する制御手段と
を設け、前記被測定物と基準面との距離が一定距離にあ
るときに前記第１の減算手段による減算出力が零となる
よう予め前記増幅手段による増幅度を設定しておくよう
にしたものである。That is, the present invention provides an automatic distance adjustment device that adjusts the distance between an object to be measured and a reference surface to a constant distance, and includes a light irradiation means for projecting light obliquely onto the object to be measured, and a pulsed light emitting means for emitting light from the light irradiation means. A modulation means for modulating Igl, a second modulation means for amplitude modulating the light emitted by the light irradiation means, and a second modulation means that is provided to move in pair with the reference surface and converts the reflected light from the object to be measured into the mosquito reflected light. A reflected light detection means detects 92 sets of analog signals according to the position, and amplifies the two sets of detection outputs obtained by the reflected light detection means, and at least one of them is amplified by making the amplification degree variable. an amplifying means for integrating the two sets of amplified outputs obtained by the amplifying means in synchronization with the first modulating means, and two sets of integrals obtained by the integrating means. A first subtraction means for calculating the difference between each pair of outputs, a ji2 subtraction means for calculating the difference between the two good sets of subtraction outputs obtained by the first subtraction means, and a subtraction means for #I2. a moving means for moving the object to be measured or the reference plane and varying the distance therebetween so that the subtraction output becomes zero; an addition means for calculating the sum of the two sets of zero subtraction outputs by the first subtraction means; control means for controlling the degree of modulation of the second modulation means so that the addition output by the means is constant; and the first subtraction means when the distance between the object to be measured and the reference plane is a certain distance The degree of amplification by the amplification means is set in advance so that the subtracted output by the amplification means becomes zero.
本発明によれは、除算器を用いることなく被測定物と基
準面との距離を検出することができ、これによシ上記距
離を高精度に制御することができる。さらに、２組のア
ナログ信号の差を零にコントロールするため、反射率の
大きく変化する被測定物に対しても検出精度が低下しな
い等の効果を奏する。According to the present invention, the distance between the object to be measured and the reference plane can be detected without using a divider, and thereby the distance can be controlled with high precision. Furthermore, since the difference between the two sets of analog signals is controlled to zero, there is an effect that the detection accuracy does not deteriorate even for objects to be measured whose reflectance changes greatly.
ｓ１図は本発明の一実施力を示す概略構成図である０図
中１は光学鏡筒で、この鏡筒１の下面（基準面）２には
対物レンズ３が取着されている。また、４はＬＥＤから
なる光源であり、この光源４は光源コントロール回路５
により発光駆動される。光源コントロール回路６は光源
４０発光をパルス変調すると共に振幅変調する機能を有
する。そして、光源４の光はスリット６を介して被測定
物７に照射される。この光照射により被測定物７から反
射した反射光はｄジシ嘗ンセンサ８にて検出される。４
ジシ冒ンセンサ８は光の入射位置に応じた２組のアナロ
グ信号を出力するもので、前記光源４から被測定物１へ
の光の入射方向と平行に前記光学鏡筒１に取着されてい
る。なお、図中９は光学鏡筒１を上下方向に移動せしめ
るための駆動回路である。Figure s1 is a schematic configuration diagram showing one implementation of the present invention. In Figure 1, 1 is an optical lens barrel, and an objective lens 3 is attached to the lower surface (reference surface) 2 of this lens barrel 1. Further, 4 is a light source consisting of an LED, and this light source 4 is connected to a light source control circuit 5.
It is driven to emit light. The light source control circuit 6 has a function of pulse modulating and amplitude modulating the light emitted by the light source 40. The light from the light source 4 is then irradiated onto the object to be measured 7 through the slit 6. The reflected light reflected from the object to be measured 7 due to this light irradiation is detected by the digital sensor 8. 4
The optical sensor 8 outputs two sets of analog signals according to the incident position of light, and is attached to the optical lens barrel 1 parallel to the direction of incidence of light from the light source 4 to the object to be measured 1. There is. Note that 9 in the figure is a drive circuit for moving the optical lens barrel 1 in the vertical direction.
また、前記対物レンズ３の主面は基準面２と同一面内に
あり、このレンズ３の焦点距離をｈとする。Further, the main surface of the objective lens 3 is in the same plane as the reference plane 2, and the focal length of this lens 3 is assumed to be h.
前記ポジシ璽ンセンサ８で検出された２組の検出出力Ａ
１ｍ Ａｘは演算増幅器１１ｍおよび抵抗１１ｂからな
る増幅器１１および演算増幅器１２ｍおよび可変抵抗Ｊ
ｊｂからなる可変利得増幅器１２にそれぞれ供給される
。増幅器１１を介して増幅された増幅出力Ｂ１は、抵抗
１３およびスイッチ１４を介して減算器１５の一方の入
力端に供給されると共に、抵抗１３およびスイッチ１６
を介して減算器１５の他方の入力端に供給される。同様
に可変利得増幅器１２を介して増幅された増幅出力Ｂ、
は抵抗１７およびスイッチ１８を介して減算器１９の一
方の入力端に供給されると共に、抵抗１７およびスイ、
チ２０を介して減算器１９の他方の入力端に供給される
。ここで、減算器１５．１９の各入力端に杖コンデンサ
２１，２２，２３．２４がそれぞれ接続されている。そ
して、抵抗１３とコンデンサ２１或いはコンデンサ２２
と、抵抗１１とコンデンサ２３或いはコン針ンサ２４と
から積分器が形成されるものとなっている。ま良、スイ
ッチ１４．１６．１８．２０はノ臂ルス発生回路２５か
らのパルス信号によｐ ０Ｎ−ＯＦＦされる。つｔシ、
上記パルス信号がＯＮのときスイッチ１４．１ｇがＯＮ
、スイッチ１６．２０がＯＦＦされ、パルス信号がＯＦ
Ｆのときスイッチ１６．２０がＯＮ、スイッチ１４，１
ＢがＯＦＦされるものとなっている。また、パルス発生
回路２５の出力パルス信号は前記光源コントロール回路
５に供給されておシ、このパルス信号によシ光源４０発
光が０Ｎ−ＯＦＦ 、つｔ９パルス変調されるものとな
っている。Two sets of detection outputs A detected by the positive sign sensor 8
1m Ax is an amplifier 11 consisting of an operational amplifier 11m and a resistor 11b, an operational amplifier 12m and a variable resistor J
jb and variable gain amplifiers 12, respectively. The amplified output B1 amplified via the amplifier 11 is supplied to one input terminal of a subtracter 15 via a resistor 13 and a switch 14, and is also supplied to one input terminal of a subtracter 15 via a resistor 13 and a switch 16.
is supplied to the other input terminal of the subtracter 15 via the subtracter 15. Similarly, the amplified output B is amplified via the variable gain amplifier 12,
is supplied to one input terminal of the subtracter 19 via the resistor 17 and the switch 18, and the resistor 17 and the switch
The signal is supplied to the other input terminal of the subtracter 19 via the channel 20. Here, cane capacitors 21, 22, 23, and 24 are connected to each input terminal of the subtractor 15, 19, respectively. Then, resistor 13 and capacitor 21 or capacitor 22
The resistor 11 and the capacitor 23 or capacitor 24 form an integrator. Well, the switches 14, 16, 18, and 20 are turned off by the pulse signal from the arm pulse generating circuit 25. Tsutshi,
When the above pulse signal is ON, switch 14.1g is ON.
, switches 16 and 20 are turned off, and the pulse signal is turned off.
When F, switch 16.20 is ON, switch 14,1
B is turned off. Further, the output pulse signal of the pulse generation circuit 25 is supplied to the light source control circuit 5, and the light emission of the light source 40 is ON-OFF and t9 pulse modulated by this pulse signal.
前記減算器１５．１９の演算出力である２組の減算出力
Ｄ１ｙＤ１はそれぞれ減算器２６および加算器２７に供
給される。減算！６２ｇの減算出力Ｅはスイッチ２８お
よびスイッチ２９を介して可変電圧電源３０に供給され
る。この電源３０は上記減算出力Ｅの大きさによシ出力
電圧が可変するもので、その出力電圧は前記駆動回路９
に供給される。そして、前記光学鏡筒１の上下方向の位
置は電源３０の出力電圧の大きさにより規定されるもの
となっている。一方、前記加算器２７の加算出力Ｆは前
記光源コントロール回路５およびレベル検出回路Ｓ１に
それぞれ供給される。そして、上記加算出力Ｆに応じて
光源コントロール回路５により前記光源４の発光強度が
可変され、すなわち振幅変調されるものとなっている。Two sets of subtraction outputs D1yD1, which are the calculation outputs of the subtracters 15 and 19, are supplied to a subtracter 26 and an adder 27, respectively. Subtraction! The subtracted output E of 62g is supplied to the variable voltage power supply 30 via the switch 28 and the switch 29. This power supply 30 has an output voltage that is variable depending on the magnitude of the subtracted output E, and the output voltage is determined by the drive circuit 9.
supplied to The vertical position of the optical barrel 1 is determined by the magnitude of the output voltage of the power source 30. On the other hand, the addition output F of the adder 27 is supplied to the light source control circuit 5 and the level detection circuit S1, respectively. The light emission intensity of the light source 4 is varied by the light source control circuit 5 in accordance with the addition output F, that is, amplitude modulated.
また、レベル検出回路３１では加算出力Ｆの振幅レベル
が検出され、このレベルが所定値以下或いは以上となる
とき前記スイッチ２８がＯＦＦされる。なお、図中３２
はスイッチ２８がＯＦＦされたときに、それまでの減算
出力Ｅをサンプルホールドするためのコンデンサである
。Further, the level detection circuit 31 detects the amplitude level of the addition output F, and when this level becomes below or above a predetermined value, the switch 28 is turned off. In addition, 32 in the figure
is a capacitor for sampling and holding the subtracted output E up to that point when the switch 28 is turned off.
このように構成された本装置の作用を説明する。まず、
スイッチ２９をＯＦＦ Ｌ、可変電圧電源３０を調整し
て駆動回路９を作動させ、基準面２から被測定物７まで
の距離がレンズ３の焦点距離りとなるようにする０次に
、光源コントロール回路５により光源４の発光をパルス
変調する。パルス変調され九光はスリット６で絞られ被
測定物１に照射され、これにより被測定物７から反射光
がポノシ冒ンセンサ８にて検出される。ポジシ冒ンセン
サ８の一方の検出出力Ａ１は増幅器１１で増幅され、前
記光源４がＯＮのとき抵抗ＩＳおよびコンデンサ２１か
らなる積分器により積分され、光源４がＯＦＦのとき抵
抗１３およびコンデンサ２２からなる積分器によシ積分
される。同様に、ポジ７冒ンセンサ８の他方の検出用カ
ム型は可変利得増幅器１２で増幅され、光源４がＯＮの
とき抵抗１７およびコンデンサ２３からなる積分器によ
り積分され、光源４がＯＦＦのとき抵抗１１およびコン
デンサ２４からなる積分器により積分される。そして、
検出出カムｌをノｆルス発生回路２５からのパルス信号
に同期させて積分した一対の積分出力Ｃ＞＊Ｃ１は減算
器１５によシ減算され、同様に検出出カム富を上記ノ臂
ルス信号に同期させて積分した一対の積分出力ｃ、 ｌ
（、／は減算器１９により減算される。これによｐ１
検出信号Ａｌｅム１から背景光がキャンセルされること
になる０次に減算器１５．１９の各減算出力ＤＩ ｅ
Ｄｓを減算器２６でさらに減算した減算出力′Ｅが零と
なるよう前記可変利得増幅器１２の利得を調整する。な
お、この状態で加算器２７の加算出力Ｆが一定となるよ
うに光源コントロール回路５によｐ光源４の発光強度が
制御されている。The operation of this device configured in this way will be explained. first,
Turn off the switch 29, adjust the variable voltage power supply 30 to operate the drive circuit 9, and adjust the distance from the reference plane 2 to the object 7 to be equal to the focal length of the lens 3. Next, control the light source. The circuit 5 pulse-modulates the light emission from the light source 4. The nine pulse-modulated lights are narrowed down by a slit 6 and irradiated onto the object to be measured 1, and the reflected light from the object to be measured 7 is detected by the sensor 8. One detection output A1 of the positive sensor 8 is amplified by an amplifier 11, and integrated by an integrator consisting of a resistor IS and a capacitor 21 when the light source 4 is ON, and is composed of a resistor 13 and a capacitor 22 when the light source 4 is OFF. It is integrated by an integrator. Similarly, the other detection cam type of the positive 7 air sensor 8 is amplified by a variable gain amplifier 12, integrated by an integrator consisting of a resistor 17 and a capacitor 23 when the light source 4 is ON, and integrated by an integrator consisting of a resistor 17 and a capacitor 23 when the light source 4 is OFF. 11 and a capacitor 24. and,
A pair of integral outputs C>*C1 obtained by integrating the detected output cam l in synchronization with the pulse signal from the nof pulse generation circuit 25 are subtracted by the subtractor 15, and similarly the detected output cam wealth is calculated from the above-mentioned arm pulse. A pair of integral outputs c, l integrated in synchronization with the signal
(, / is subtracted by the subtractor 19. As a result, p1
Each subtraction output DI e of the zero-order subtractor 15.19 from which the background light is canceled from the detection signal Alem 1
The gain of the variable gain amplifier 12 is adjusted so that the subtracted output 'E obtained by further subtracting Ds by the subtracter 26 becomes zero. Note that in this state, the light emission intensity of the P light source 4 is controlled by the light source control circuit 5 so that the addition output F of the adder 27 is constant.
次に、スイッチ２９をＯＮするが、この状態では減算出
力Ｅが零であるため電源３０の電圧は変化せず光学鏡筒
１は移動しない。いま、被測定物１と基準面２との距離
がΔｈだけ変化したとする。この場合、被測定物１から
の反射光がポジ７冒ンセンｔ８上で移動する距離ｌ）は
、ｉｌ２図に示す如く被測定物７に入射する光の入射角
を−とすれは
Δｈ
ノＪ＝−・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・（ｌンｔｘＩｍ＃
で示される。光源４がＯＮのときポジ７冒ンセンサ８の
検出出力Ａ１ ＃ Ａ諺の各電流ｓｌ ＃ ｓｆｉはと
なる。良だし、ｉは光源４がＯＮすることにょる４ジシ
冒ンセン？８の全電流、ｉｌは背景光によるポジ７冒ン
センサ８の全電流、Ｌはポジシ曹ンセ／す８の検出有効
長、）はΔｈ移動する前のポジ７冒ンセンサ８のスポッ
ト位置である。Next, the switch 29 is turned on, but in this state, the subtraction output E is zero, so the voltage of the power source 30 does not change and the optical lens barrel 1 does not move. Suppose now that the distance between the object to be measured 1 and the reference plane 2 changes by Δh. In this case, the distance l) that the reflected light from the object to be measured 1 moves on the positive point 7 and t8 is Δh, assuming the angle of incidence of the light incident on the object to be measured 7 is -, as shown in figure il2. ＝−・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・(Indicated by ntxIm#. When the light source 4 is ON, the detection output A1 of the positive 7 sensor 8. is the total current of the positive sensor 8 due to the light source 4 turning on, il is the total current of the positive sensor 8 due to background light, L is the effective detection length of the positive sensor 8, ) is the movement by Δh This is the spot position of the positive sensor 8 before the positive 7 exposure.
また、光源４がＯＮのときのコンデンサ２１．７３の両
端電圧ｅｌｌｓ・ｌは
となる。ただし、Ｒ１１ｅ Ｒｌｍは前記抵抗１１ｂ、
１２ｂの各抵抗値である。Further, when the light source 4 is ON, the voltage across the capacitor 21.73 is ells·l. However, R11e Rlm is the resistor 11b,
12b.
一方、光源４がＯＦＦのときポジシロンセンサ８の検出
出力Ａｌ ｅ Ａｍの６電ｆＩＬｉｌ’、４Ｂ’はとな
り、このときのコンデンサ２２．２４の両端電圧ｅ１１
ｍ ｅ１４は
となる。On the other hand, when the light source 4 is OFF, the detection output Al e Am of the positron sensor 8 becomes 6 voltages fILil', 4B', and the voltage e11 across the capacitors 22 and 24 at this time is
m e14 becomes.
減算器１５．１９の各減算出力ｅＩＩ ｅ ｅｔａ（Ｄ
Ｉ ｅ Ｄｓ ）は
となシ、減算器２６の減算出力ａＳＳ（ト）は６０”１
＠−６１１
・・・・・・・・・・・・・・・（７）るように調整さ
れているので減算出力ｅ２・はと表わされる。この減算
出力ｅ１・がスイッチ２Ｂ、１９を介して電源３０に供
給され電源電圧を可変させることによシ、駆動回路９に
より光学鏡筒１が上下動され、Δノが零となＦ） ｅｓ
−が零となるように制御される。したがって、基準面２
と被測定物２との距離は常にレンズ３の焦点距離に保持
されることになる。Each subtraction output eII e eta(D
The subtraction output aSS(g) of the subtractor 26 is 60"1
@-611 ・・・・・・・・・・・・・・・(7) Since it is adjusted so that the subtraction output e2 is expressed as. This subtraction output e1 is supplied to the power supply 30 via the switches 2B and 19, and by varying the power supply voltage, the optical lens barrel 1 is moved up and down by the drive circuit 9, and Δ becomes zero.
- is controlled so that it becomes zero. Therefore, reference plane 2
The distance between the object 2 and the object 2 to be measured is always maintained at the focal length of the lens 3.
ところで、前記第８式において電流（が零となっても減
算出力ａＳＳは零となるため、加算器２７の加算出力６
ｍ？（６）が一定となるように光源コントロール回路５
で光源４の発光強度が制御されている。被測定物７の反
射率が変化し、光源コントロール回路６で光源４０発光
強度を制御できなくなる種変化した場合、レベル検出回
路３１によりスイッチ２８がＯＦＦされる。そしてこの
場合、コンデンサ３２に蓄えられた電荷で駆動回路９が
ホールドされ、被測定物７０反射率が復旧するまでこの
状態が保持される。By the way, in the eighth equation, even if the current ( becomes zero, the subtraction output aSS becomes zero, so the addition output 6 of the adder 27
m? The light source control circuit 5
The light emission intensity of the light source 4 is controlled. When the reflectance of the object to be measured 7 changes to the extent that the light source control circuit 6 cannot control the emission intensity of the light source 40, the level detection circuit 31 turns off the switch 28. In this case, the drive circuit 9 is held by the charge stored in the capacitor 32, and this state is maintained until the reflectance of the object to be measured 70 is restored.
かくして本装置によれば、ポジシ１ンセンサ８の検出出
力から背景光をキャンセルした出力ＤＩ ｅ Ｄ＊の差
が零となるように駆動回路９をコントロールしているの
で、反射光の強度に影響され細く、被測定物１の反射率
が大きく変化しても、基準面２と被測定物７との距離を
レンズ３の焦点距離に正確にコントロールすることがで
きる。さらに、除算器を用いることなく減算器１！！、
１９．２６および加算器２７のみで演算回路を実現して
いるので、上記距離を高精度に制御することができる。Thus, according to the present device, the drive circuit 9 is controlled so that the difference between the detection output of the positive sensor 8 and the output DI e D*, which cancels background light, is zero, so that the difference is not affected by the intensity of reflected light. Even if the reflectance of the object 1 to be measured changes greatly, the distance between the reference plane 2 and the object 7 to be measured can be accurately controlled to the focal length of the lens 3. Furthermore, subtractor 1 without using a divider! ! ,
Since the arithmetic circuit is realized only by 19.26 and the adder 27, the distance can be controlled with high precision.
なお、本発明は上述した実施例に限定されるものではな
い０例えば、前記被測定物からの反射光を検出する光検
出器としては、反射光の入射位置に応じて２つのアナ四
グ信号を出力するもので、かつ反射光の強度が一定の場
合その出力の和が一定となるものであればよい。ま次、
基準面と被測定物との距離をレンズの焦点距離に合わせ
るものに限らず、上記距離を所望値に保持する必要のあ
るものに適用することができる。その他、本発明の要旨
を逸脱しない範囲で、種々変形して実施することができ
る。Note that the present invention is not limited to the embodiments described above. For example, the photodetector for detecting the reflected light from the object to be measured may detect two analog signals depending on the incident position of the reflected light. It is sufficient if the output output is constant and the sum of the outputs is constant when the intensity of reflected light is constant. Matsugi,
The present invention is not limited to adjusting the distance between the reference plane and the object to be measured to match the focal length of a lens, and can be applied to any other device in which the distance needs to be maintained at a desired value. In addition, various modifications can be made without departing from the gist of the present invention.
第１図は本発明の一実施例を示す概略構成図、＃１２図
は上記実施例の作用を説明する九めの模式図である。
１・・・光学鏡筒、２・・・基準面、３・・・対物レン
ズ、４・・・光源、５・・・光源コントロール回１ｒ、
ｇ・・・スリ、ト、１・・・被測定物、８・・・ポジシ
嘗ンセンサ、９・・・駆動回路、１１・・・増幅器、１
２・・・可変利得増幅器、１３，１７１・・・抵抗、１
４ 、１６ 、 ｆ ８゜２０．２１１．２９・・・ス
イッチ、１５．１９・・・減算器（第１の減算器）、２
１，２２，２３．２４・・・コンデンｆ、２５・・・パ
ルス発生口ｊＬ ｘ ｇ・・・減算器（第２の減算器）
、２７・・・加算器、３０・・・可変電圧電源、３１・
・・レベル検出回路、３２・・・サンプルホールド用コ
ンデンサ。FIG. 1 is a schematic diagram showing an embodiment of the present invention, and FIG. 12 is a ninth schematic diagram illustrating the operation of the embodiment. DESCRIPTION OF SYMBOLS 1... Optical lens barrel, 2... Reference surface, 3... Objective lens, 4... Light source, 5... Light source control time 1r,
g... pickpocket, g, 1... object to be measured, 8... position sensor, 9... drive circuit, 11... amplifier, 1
2...Variable gain amplifier, 13,171...Resistor, 1
4, 16, f 8゜20.211.29...Switch, 15.19...Subtractor (first subtractor), 2
1, 22, 23.24...Condenser f, 25...Pulse generation port jL x g...Subtractor (second subtractor)
, 27... Adder, 30... Variable voltage power supply, 31.
...Level detection circuit, 32...Sample and hold capacitor.
Claims (1)
離合わせ装置において、上記被測定物に斜めから光を当
てる光照射手段と、この光照射手段による光をパルス変
調する第１の変調手段と、上記光照射手段による光を振
幅変調する第２の変調手段と、前記基準面と一対的に移
動するよう設けられ前記被測定物からの反射光を該反射
光の位置に応じ九２組のアナｐ／信号として検出する反
射光検出手段と、この反射光検出手段によｐ得られた２
組の検出出力をそれぞれ増幅すると共に少なくとも一方
は増幅度を可変可能にして増幅する増幅手段と、前記第
１の変調手段と同期させて上記増幅中ＲＫよｐ得られた
２組の増幅出力をそれぞれ対で積分する積分手段と、こ
の積分手段によや得られた２組の積分出力の各対の差を
それぞれ演算する第１の減算手段と、この第１の減算手
段により得られた２組の減算出力の差を演算する第２の
減算手段と、この第２の減算手段による減算出力が零に
なるよう前記被測定智或いけ基準面を移動しこれらの距
離を可変する移動手段と、前記第１の減算手段による２
組の減算出力の和を演算する加算手段と、この加算手段
による加算出力が一定となるよう前記ｔｓ２の変調手段
の変調度を制御する制御手段とを具備し、前記被測定−
と基準面との距離が一定距離にあるときに前記第１の減
算手段による減算出力が零となるよう予め前記増幅手段
による′増幅度を設定しておくことを特徴とする自動距
離合わせ装置。An automatic distance adjustment device that adjusts the distance between the object to be measured and a reference surface to a constant distance, comprising: a light irradiation means for applying light to the object to be measured obliquely; and a first modulation device for pulse-modulating the light emitted by the light irradiation means. means, a second modulation means for amplitude modulating the light emitted by the light irradiation means, and a second modulation means provided to move in a pair with the reference surface, and which adjusts the reflected light from the object to be measured according to the position of the reflected light. a reflected light detection means for detecting a set of ana p/signals, and a p obtained by the reflected light detection means.
an amplification means for respectively amplifying the detection outputs of the sets and making at least one variable the degree of amplification; an integrating means that integrates in pairs; a first subtracting means that calculates the difference between each pair of the two sets of integral outputs obtained by the integrating means; a second subtraction means for calculating the difference between the subtraction outputs of the sets; and a moving means for moving the tip to be measured or the reference plane and varying the distance thereof so that the subtraction output by the second subtraction means becomes zero. , 2 by the first subtraction means
comprising an adding means for calculating the sum of the subtraction outputs of the set; and a control means for controlling the modulation degree of the modulation means of the ts2 so that the addition output by the adding means is constant;
An automatic distance adjusting device characterized in that the degree of amplification by the amplifying means is set in advance so that the subtracted output by the first subtracting means becomes zero when the distance between the first subtracting means and the reference plane is a constant distance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1933182A JPS58135910A (en) | 1982-02-09 | 1982-02-09 | Automatic range controller |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1933182A JPS58135910A (en) | 1982-02-09 | 1982-02-09 | Automatic range controller |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58135910A true JPS58135910A (en) | 1983-08-12 |
| JPS6316686B2 JPS6316686B2 (en) | 1988-04-11 |
Family
ID=11996419
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1933182A Granted JPS58135910A (en) | 1982-02-09 | 1982-02-09 | Automatic range controller |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58135910A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04204811A (en) * | 1990-11-30 | 1992-07-27 | Fuji Photo Film Co Ltd | Active type distance measuring method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5842411A (en) * | 1981-09-07 | 1983-03-11 | 大塚化学株式会社 | Stabilizing treatment method for size of woody material |
-
1982
- 1982-02-09 JP JP1933182A patent/JPS58135910A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5842411A (en) * | 1981-09-07 | 1983-03-11 | 大塚化学株式会社 | Stabilizing treatment method for size of woody material |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04204811A (en) * | 1990-11-30 | 1992-07-27 | Fuji Photo Film Co Ltd | Active type distance measuring method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6316686B2 (en) | 1988-04-11 |
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