JPH08152550A - Automatic focusing device of microscope - Google Patents
Automatic focusing device of microscopeInfo
- Publication number
- JPH08152550A JPH08152550A JP29284594A JP29284594A JPH08152550A JP H08152550 A JPH08152550 A JP H08152550A JP 29284594 A JP29284594 A JP 29284594A JP 29284594 A JP29284594 A JP 29284594A JP H08152550 A JPH08152550 A JP H08152550A
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- focus
- focusing
- image
- signal
- microscope
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、顕微鏡自動焦点装置に
関し、特に、光学顕微鏡により試料面上のパターンを観
察する際に自動的に焦点を合わせる顕微鏡自動焦点装置
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microscope autofocus device, and more particularly to a microscope autofocus device for automatically focusing when observing a pattern on a sample surface with an optical microscope.
【０００２】[0002]
【従来の技術】従来の技術としては、例えば、特開昭５
３−５０８５１号公報に記載の顕微鏡自動焦点装置があ
る。2. Description of the Related Art As a conventional technique, for example, Japanese Patent Laid-Open No.
There is a microscope automatic focusing device described in Japanese Patent Laid-Open No. 3-50851.
【０００３】従来の顕微鏡自動焦点装置について図面を
参照して詳細に説明する。A conventional microscope autofocus device will be described in detail with reference to the drawings.
【０００４】図６は、従来の一例を示す構成図である。
図６に示す顕微鏡自動焦点装置は、上下ステージ１上に
載せた試料２の像を拡大する対物レンズ３と、光学顕微
鏡の結像光軸を観察光軸４１と２本の焦点検出光軸４２
とに分割する光分割器としての２枚のハーフミラー５
と、２本の各焦点検出光軸４２上にあって、観察対象が
合焦位置から所定量ｚだけ前焦点側および後焦点側にあ
るときの対物レンズ３による実像位置に配置された２個
の撮像手段である、前焦点ラインセンサ６２および後焦
点ラインセンサ６３と、後焦点ラインセンサ６３に検出
光を導くための全反射ミラー７と、各ラインセンサ６
２，６３のそれぞれに接続され、各ラインセンサ６２，
６３から出力される画像信号ａ2 ，ａ3 の合焦度を検出
して合焦度信号ｂ2 ，ｂ3 を出力する２個の合焦度検出
手段９と、２個の合焦度検出手段９からの合焦度信号ｂ
2 ，ｂ3 の差動増幅を行い焦点検出信号ｃを出力する差
動アンプ１０とを含んで構成される。FIG. 6 is a block diagram showing a conventional example.
The microscope auto-focusing device shown in FIG. 6 includes an objective lens 3 for enlarging an image of a sample 2 placed on the upper and lower stages 1, an observation optical axis 41 for forming an optical axis of an optical microscope, and two focus detecting optical axes 42.
Two half mirrors 5 as an optical splitter for splitting into and
And two on the respective focus detection optical axes 42, which are arranged at the real image position by the objective lens 3 when the observation target is on the front focus side and the rear focus side by the predetermined amount z from the in-focus position. The front focus line sensor 62 and the rear focus line sensor 63 which are the image pickup means of the total reflection mirror 7 for guiding the detection light to the rear focus line sensor 63, and each line sensor 6.
2, 63 connected to each of the line sensors 62,
From the two focus degree detecting means 9 for detecting the focus degree of the image signals a2 and a3 outputted from the reference numeral 63 and outputting the focus degree signals b2 and b3, and the two focus degree detecting means 9. Focus signal b
2, a differential amplifier 10 for performing differential amplification on b3 and outputting a focus detection signal c.
【０００５】図２は合焦度検出手段９の内部ブロック図
である。合焦度検出手段９は、微分回路９１と、積分回
路９２とで構成され、画像信号ａ2 ，ａ3 の画像信号波
形について微分回路９１で微分の絶対値を演算し、積分
回路９２でこの微分絶対値を１スキャン分積算して合焦
度信号ｂ2 ，ｂ3 として出力する。FIG. 2 is an internal block diagram of the focus degree detection means 9. The focus degree detecting means 9 is composed of a differentiating circuit 91 and an integrating circuit 92. The differentiating circuit 91 calculates the absolute value of the differential of the image signal waveforms of the image signals a2 and a3, and the integrating circuit 92 calculates the absolute difference. The values are integrated for one scan and output as focusing degree signals b2 and b3.
【０００６】次に、図６に示す顕微鏡自動焦点装置の動
作を説明する。Next, the operation of the microscope autofocus device shown in FIG. 6 will be described.
【０００７】図３は焦点位置による合焦度信号ｂ2 〜ｂ
3 の変化を示す図であり、図４は焦点位置による焦点検
出信号ｃの変化を示す図である。観察系の焦点が＋ｚ
（前焦点側）から−ｚ（後焦点側）まで移動すると、前
焦点ラインセンサ６２は、＋ｚのときに最も焦点の合っ
た画像信号ａ2 を出力し、観察系の合焦点に近づくにつ
れて画像信号ａ2 はぼけてくる。このとき、画像信号に
含まれる高周波成分の量は合焦の程度により変化するこ
とを利用して、合焦度検出部９で画像信号ａ2 の微分絶
対値の積算量を求めて合焦度信号ｂ2 として出力する
と、この合焦度信号ｂ2 は＋ｚのときが最大値で合焦に
近づくにつれて出力が低くなる。また、後焦点ラインセ
ンサ６３では逆の動作となり、合焦度信号ｂ3 は−ｚの
ときが最大値で合焦に近づくにつれて出力が低くなる。
従って、差動アンプ１０でこれら２つの合焦度信号ｂ2
，ｂ3 の差動増幅を行うと、前焦点側が正で後焦点側
が負のいわゆるＳ曲線なる焦点検出信号ｃが得られる。
この信号をフィードバック信号として、サーボ制御によ
りモータなどで上下ステージ１を移動し、焦点検出信号
ｃの値が０になるように制御を行うことで焦点を合わせ
る。FIG. 3 shows focusing degree signals b2 to b depending on the focus position.
3 is a diagram showing a change in 3 and FIG. 4 is a diagram showing a change in the focus detection signal c depending on the focus position. Focus of observation system is + z
When moving from (front focus side) to -z (back focus side), the front focus line sensor 62 outputs the most focused image signal a2 at + z, and the image signal becomes closer to the in-focus point of the observation system. a2 is blurred. At this time, the amount of high-frequency components included in the image signal changes depending on the degree of focusing, and the focusing degree detection unit 9 obtains the integrated amount of the differential absolute value of the image signal a2 to obtain the focusing degree signal. When output as b2, the focus degree signal b2 has the maximum value at + z, and the output decreases as the focus approaches. Further, in the rear focus line sensor 63, the reverse operation is performed, and the focus degree signal b3 has the maximum value at -z, and the output decreases as the focus approaches.
Therefore, in the differential amplifier 10, these two focus degree signals b2
, B3 are differentially amplified, a focus detection signal c which is a so-called S curve having a positive front side and a negative rear side is obtained.
Using this signal as a feedback signal, the upper and lower stages 1 are moved by a motor or the like by servo control, and control is performed so that the value of the focus detection signal c becomes 0, thereby focusing.
【０００８】[0008]
【発明が解決しようとする課題】上述した従来の顕微鏡
自動焦点装置は、合焦位置の前後に配置したラインセン
サからの画像信号の合焦度値を差動増幅した焦点検出信
号をフィードバック信号としてフォーカスサーボをかけ
ている。この際、合焦度値の最大値は観察パターンの高
周波成分量と輝度値により変化するため、焦点検出信号
の最大・最小値も変化する。すなわち、フォーカスサー
ボのフィードバック信号ゲインが観察パターンにより変
化することになる。従って、例えば半導体ウェハ上のロ
ジック配線パターン等のようなパターン配置密度すなわ
ち高周波成分量と輝度差が場所により変化する試料を連
続的に全面観察しようとすると、観察場所により、フィ
ードバック信号ゲインが変化し、過大になって制御系が
発振したり、過小になって位置決め精度が劣化する、と
いう欠点があった。SUMMARY OF THE INVENTION The conventional microscope autofocus device described above uses a focus detection signal obtained by differentially amplifying a focus degree value of an image signal from a line sensor arranged before and after a focus position as a feedback signal. Focus servo is applied. At this time, the maximum focus value changes depending on the amount of high-frequency components of the observation pattern and the brightness value, so the maximum and minimum values of the focus detection signal also change. That is, the feedback signal gain of the focus servo changes depending on the observation pattern. Therefore, when attempting to continuously observe the entire surface of a sample, such as a logic wiring pattern on a semiconductor wafer, where the pattern arrangement density, that is, the amount of high-frequency components and the difference in brightness change depending on the location, the feedback signal gain changes depending on the observation location. However, there is a drawback that the control system oscillates when it becomes too large, or the positioning accuracy deteriorates when it becomes too small.
【０００９】[0009]
【課題を解決するための手段】本発明の顕微鏡自動焦点
装置は、光学顕微鏡の結像光軸を観察光軸と３本の焦点
検出光軸とに分割する光分割器と、前記３本の各焦点検
出光軸上にあって、合焦時の対物レンズによる実像位置
と、観察対象が合焦位置から所定量だけ前焦点側および
後焦点側にずれたときの前記対物レンズによる実像位置
とに配置された３個の撮像手段と、前記撮像手段のそれ
ぞれから出力される画像信号をもとに合焦度を検出して
合焦度信号を出力する３個の合焦度検出手段と、前焦点
側と後焦点側の２つの合焦度信号の差動増幅を行う差動
アンプと、前記３個の合焦度検出手段からそれぞれ出力
される３つの合焦度信号をもとに補正信号を演算して出
力する補正値演算手段と、前記差動アンプと前記補正値
演算手段との出力信号を乗算して焦点検出信号を出力す
る乗算回路とを含むことを特徴とする。SUMMARY OF THE INVENTION A microscope autofocus device according to the present invention comprises an optical splitter for splitting an image forming optical axis of an optical microscope into an observation optical axis and three focus detection optical axes, and the three optical splitters. On each focus detection optical axis, a real image position by the objective lens at the time of focusing, and a real image position by the objective lens when the observation target is deviated from the focus position to the front focus side and the rear focus side by a predetermined amount. And three focusing degree detecting means for detecting a focusing degree based on an image signal output from each of the imaging means and outputting a focusing degree signal. Correction is performed based on a differential amplifier that differentially amplifies two focus degree signals on the front focus side and the rear focus side, and three focus degree signals respectively output from the three focus degree detecting means. Correction value calculation means for calculating and outputting a signal, and outputs of the differential amplifier and the correction value calculation means Characterized in that it comprises a multiplier circuit for multiplying outputs a focus detection signal No..
【００１０】[0010]
【実施例】次に、本発明について図面を参照して詳細に
説明する。The present invention will be described in detail with reference to the drawings.
【００１１】図１は、本発明の一実施例を示す構成図で
ある。図１に示す顕微鏡自動焦点装置は、上下ステージ
１上に載せた試料２の像を拡大する対物レンズ３と、光
学顕微鏡の結像光軸を観察光軸４１と３本の焦点検出光
軸４２とに分割する光分割器としての３枚のハーフミラ
ー５と、３本の各焦点検出光軸４２上にあって、合焦時
の対物レンズ３による実像位置と、観察対象が合焦位置
から所定量ｚだけ前焦点側および後焦点側にずれたとき
の対物レンズ３による実像位置とに配置された３個の撮
像手段である、合焦点ラインセンサ６１と前焦点ライン
センサ６２と後焦点ラインセンサ６３と、後焦点ライン
センサ６３に検出光を導くための全反射ミラー７と前焦
点ラインセンサ６２の前にあって、他２つのラインセン
サと受光量を合わせるために光量を１／２にする５０％
ＮＤフィルタ８と、各ラインセンサ６１〜６３のそれぞ
れに接続され、各ラインセンサ６１〜６３から出力され
る画像信号ａ1 〜ａ3 の合焦度を検出して合焦度信号ｂ
1 〜ｂ3 を出力する３個の合焦度検出手段９と、前焦点
ラインセンサ６２と後焦点ラインセンサ６３に接続され
た２個の合焦度検出手段９からの合焦度信号ｂ2 ，ｂ3
の差動増幅を行い焦点検出信号ｃを出力する差動アンプ
１０と、３個の合焦度検出手段９に接続され、合焦度信
号ｂ1 〜ｂ3 の値をもとに補正値を演算して補正信号ｄ
を出力する補正値演算手段１１と、差動アンプ１０と補
正値演算手段１１とに接続され、焦点検出信号ｃと補正
信号ｄを乗算して焦点ずれ信号ｅを出力する乗算回路１
２とを含んで構成される。FIG. 1 is a block diagram showing an embodiment of the present invention. The microscope auto-focusing device shown in FIG. 1 includes an objective lens 3 for enlarging an image of a sample 2 placed on an upper and lower stage 1, an observation optical axis 41 for forming an optical axis of an optical microscope, and three focus detection optical axes 42. There are three half mirrors 5 as light splitters for dividing into two, and the real image position by the objective lens 3 at the time of focusing on each of the three focus detection optical axes 42 and the observation target from the focusing position. Focusing line sensor 61, front focus line sensor 62, and rear focus line, which are three imaging means arranged at the real image position by objective lens 3 when they are deviated to the front focus side and the rear focus side by a predetermined amount z. In front of the sensor 63, the total reflection mirror 7 for guiding the detection light to the back focus line sensor 63, and the front focus line sensor 62, the light amount is halved in order to match the received light amount with the other two line sensors. 50%
The ND filter 8 and each of the line sensors 61 to 63 are connected to each other, and the focus degree of the image signals a1 to a3 output from each of the line sensors 61 to 63 is detected to detect the focus degree signal b.
Focusing degree signals b2 and b3 from three focusing degree detecting means 9 for outputting 1 to b3 and two focusing degree detecting means 9 connected to the front focus line sensor 62 and the rear focus line sensor 63.
Is connected to the differential amplifier 10 for performing the differential amplification of the above and outputting the focus detection signal c and the three focus degree detecting means 9, and the correction value is calculated based on the values of the focus degree signals b1 to b3. Correction signal d
A multiplication circuit 1 which is connected to the correction value calculation means 11, which outputs the differential amplifier 10 and the correction value calculation means 11, and which outputs the defocus signal e by multiplying the focus detection signal c and the correction signal d.
2 is included.
【００１２】図２は合焦度検出手段９の内部ブロック図
である。合焦度検出手段９は、微分回路９１と、積分回
路９２とで構成され、画像信号ａ1 〜ａ3 の画像信号波
形について微分回路９１で微分の絶対値を演算し、積分
回路９２でこの微分絶対値を１スキャン分積算し、合焦
度信号ｂ1 〜ｂ3 として出力する。FIG. 2 is an internal block diagram of the focus degree detecting means 9. The focus degree detection means 9 is composed of a differentiating circuit 91 and an integrating circuit 92. The differentiating circuit 91 calculates the absolute value of the differential of the image signal waveforms of the image signals a1 to a3, and the integrating circuit 92 calculates the absolute difference. The values are integrated for one scan and output as focusing degree signals b1 to b3.
【００１３】次に、
図１，図２に示す顕微鏡自動焦点装置の動作を説明す
る。Next,
The operation of the microscope autofocus device shown in FIGS. 1 and 2 will be described.
【００１４】図３は焦点位置による合焦度信号ｂ2 〜ｂ
3 の変化を示す図であり、図４は焦点位置による焦点検
出信号ｃの変化を示す図である。観察系の焦点が＋ｚ
（前焦点側）から−ｚ（後焦点側）まで移動すると、前
焦点ラインセンサ６２は、＋ｚのときに最も焦点の合っ
た画像信号ａ2 を出力し、観察系の合焦点に近づくにつ
れて画像信号ａ2 はぼけてくる。このとき、従来技術で
も利用されているように、画像信号に含まれる高周波成
分の量は合焦の程度により変化する。よって、合焦度検
出部９で画像信号ａ2 の微分絶対値の積算量を求めて合
焦度信号ｂ2 として出力すると、この合焦度信号ｂ2 は
＋ｚのときが最大値で合焦に近づくにつれて出力が低く
なる。また、後焦点ラインセンサ６３では逆の動作とな
り、合焦度信号ｂ3 は−ｚのときが最大値で合焦に近づ
くにつれて出力が低くなる。従って、差動アンプ１０で
これら２つの合焦度信号ｂ2 ，ｂ3 の差動増幅を行う
と、前焦点側が正で後焦点側が負のいわゆるＳ曲線なる
焦点検出信号ｃが得られる。また、当然のことながら合
焦点ラインセンサ６１による合焦度信号ｂ1 は、合焦位
置で最大であり＋ｚおよび−ｚに近づくに従い低くな
る。FIG. 3 shows focusing degree signals b2 to b depending on the focus position.
3 is a diagram showing a change in 3 and FIG. 4 is a diagram showing a change in the focus detection signal c depending on the focus position. Focus of observation system is + z
When moving from (front focus side) to -z (back focus side), the front focus line sensor 62 outputs the most focused image signal a2 at + z, and the image signal becomes closer to the in-focus point of the observation system. a2 is blurred. At this time, the amount of high-frequency components included in the image signal changes depending on the degree of focusing, as is used in the related art. Therefore, when the focus degree detection unit 9 obtains the integrated amount of the differential absolute value of the image signal a2 and outputs it as the focus degree signal b2, the focus degree signal b2 is the maximum value when + z, and as the focus approaches the focus. Output is low. Further, in the rear focus line sensor 63, the reverse operation is performed, and the focus degree signal b3 has the maximum value at -z, and the output decreases as the focus approaches. Therefore, when the differential amplifier 10 differentially amplifies these two focusing degree signals b2 and b3, a focus detection signal c which is a so-called S curve in which the front focus side is positive and the rear focus side is negative is obtained. Further, as a matter of course, the focus degree signal b1 from the focus line sensor 61 is maximum at the focus position and becomes lower as it approaches + z and -z.
【００１５】ここで、各合焦度信号ｂ1 ，ｂ2 ，ｂ3
は、観察系の焦点位置を変数ｘとして、式（１）〜式
（３）の２次関数で近似でき、焦点検出信号ｃはｂ2 と
ｂ3 の差分なので式（４）で表される。ここでｐ，ｑは
試料２のパターンにより決定される係数であり、パター
ンの高周波成分量と輝度差により変化する。Here, each focus degree signal b1, b2, b3
Can be approximated by a quadratic function of the formulas (1) to (3) with the focus position of the observation system as a variable x, and the focus detection signal c is the difference between b2 and b3 and is represented by the formula (4). Here, p and q are coefficients determined by the pattern of the sample 2, and change depending on the high frequency component amount of the pattern and the brightness difference.
【００１６】 ｂ1 ＝−ｐｘ2 ＋ｑ ……… （１） ｂ2 ＝−ｐ（ｘ−ｚ）2 ＋ｑ ……… （２） ｂ3 ＝−ｐ（ｘ＋ｚ）2 ＋ｑ ……… （３） ｃ ＝ｂ2 −ｂ3 ＝４ｐｚｘ ……… （４） 式（４）で示されるように、焦点検出信号ｃには試料２
のパターンにより値が変化する係数ｐが含まれる。その
ため従来技術のようにフォーカスサーボのフィードバッ
ク信号として焦点検出信号ｃを使用すると、フィードバ
ックゲインが観察パターンにより変化し、過大になって
制御系が発振したり、過小になって位置決め精度が劣化
する場合が生じる。B1 = -px2+ Q ......... (1) b2 = -p (x-z)2+ Q ... (2) b3 = -p (x + z)2+ Q ………… (3) c = b2-b3 = 4pzx ………… (4) As shown in the equation (4), the sample 2 is included in the focus detection signal c.
The coefficient p whose value changes depending on the pattern of is included. That
Therefore, the focus servo feedback
If the focus detection signal c is used as the
Clock gain changes depending on the observation pattern and becomes excessive
Positioning accuracy deteriorates because the control system oscillates or becomes too small.
There is a case to do.
【００１７】そこで次に、各合焦度信号ｂ1 ，ｂ2 ，ｂ
3 をもとに補正値演算手段１１で１／ｐを求めて補正信
号ｄとし、乗算回路１２により焦点検出信号ｃと乗算し
て得られる焦点ずれ信号ｅをフィードバック信号として
フォーカスサーボをかけ、図示しない制御・駆動手段に
より上下ステージ１を上下させて自動焦点合わせを行
う。ここで、補正値演算手段１１は、式（１）〜式
（３）より、式（５）で表される演算を行う。よって、
焦点ずれ信号ｅは式（６）で表され、パターンにより変
化する係数ｐ，ｑを含まないため、フィードバックゲイ
ンは一定となる。Then, next, each focus degree signal b1, b2, b
Based on 3, the correction value calculation means 11 calculates 1 / p to obtain the correction signal d, and the focus shift signal e obtained by multiplying the focus detection signal c by the multiplication circuit 12 is used as a feedback signal to apply focus servo, The automatic focusing is performed by moving the upper and lower stages 1 up and down by the control / driving means. Here, the correction value calculation means 11 performs the calculation represented by the equation (5) from the equations (1) to (3). Therefore,
The defocus signal e is expressed by the equation (6) and does not include the coefficients p and q that change depending on the pattern, so that the feedback gain is constant.
【００１８】 ｄ＝１／ｐ＝−２ｚ2 ／（ｂ2 ＋ｂ3 −２ｂ1 ） ……… （５） ｅ＝ｃ・ｄ＝４ｚｘ ……… （６） また、図５は本発明の別の実施例を示す構成図である。
図５に示す顕微鏡自動焦点装置は、無限遠光学系の光学
顕微鏡に本発明を適用したものであり、顕微鏡光軸上に
あって対物レンズ３の次段に配置され実像をつくる結像
レンズ１３を含んで構成される以外は、図１の実施例と
同一構成である。D = 1 / p = -2z 2 / (b 2 + b 3 -2b 1) (5) e = c · d = 4zx (6) FIG. 5 shows another embodiment of the present invention. It is a block diagram which shows.
The microscope auto-focusing device shown in FIG. 5 is obtained by applying the present invention to an optical microscope having an infinity optical system, and is arranged on the optical axis of the microscope at the next stage of the objective lens 3 to form a real image. The configuration is the same as that of the embodiment of FIG.
【００１９】また、撮像手段としては、ラインセンサ以
外に、２次元センサも適用できる。As the image pickup means, a two-dimensional sensor can be applied in addition to the line sensor.
【００２０】また、合焦度検出手段としては、画像信号
の微分値の絶対値を検出する以外に、例えば特開平３−
４４６０８号公報の「自動焦点合わせ方法」に示される
ような画像信号の輝度分散値を検出する方法
が適用できる。これは、像が合焦に近づくほどコントラ
ストが明瞭になって輝度分布が広がり、輝度分散値が大
きくなることを利用したもので、画像信号ａ1 〜ａ3 か
ら輝度分散値を求めてその値を合焦度信号ｂ1 〜ｂ3 と
して出力する。さらには、例えば、１９９３年度精密工
学会春期大会学術講演会講演論文集４２３〜４２４頁の
論文「画像合成による光学式顕微鏡の長焦点深度化」に
示されるような、画像信号の直交変換を行いこの直交変
換像の高次成分量を検出する方法も適用できる。
これは、像が合焦に近づくほど、直交変換後の高次成分
が大きくなることを利用したもので、画像信号ａ1〜ａ3
の直
交変換を行い、その直交変換像に含まれる高次成分量を
求めてその値を合焦度信号ｂ1 〜ｂ3 として出力する。 Further, as the focus degree detecting means, in addition to detecting the absolute value of the differential value of the image signal, for example, Japanese Unexamined Patent Publication No.
Method for detecting luminance dispersion value of image signal as shown in "Automatic focusing method" of Japanese Patent No. 44608
Can be applied. This is because the contra
Stroke becomes clear, brightness distribution spreads, and brightness dispersion value is large
Which was used to be a listening, image or signal a1 ~a3
Then, the brightness dispersion value is obtained from the
And output. Further , for example, the orthogonal transformation of the image signal is performed as shown in the paper “Long focal depth of optical microscope by image synthesis” on pages 423 to 424 of Proceedings of the 1993 Precision Engineering Society Spring Conference. A method of detecting the amount of higher-order components of this orthogonal transformation image can also be applied.
This is because the closer the image is to the focus, the higher order components after orthogonal transformation.
Utilizes the fact that the larger the image signal a1~a3
Directly
Performs alternating transformation, and calculates the amount of higher-order components included in the orthogonal transformation image.
Determined and outputs its value as focus degree signal b1 to b3.
【００２１】[0021]
【発明の効果】本発明の顕微鏡自動焦点装置は、合焦位
置の前後に配置した２つの撮像手段からの画像信号の合
焦度値を差動増幅した焦点検出信号をフィードバック信
号としてフォーカスサーボをかける代わりに、合焦位置
および合焦位置の前後に配置した３つの撮像手段からの
画像信号の合焦度値をもとに算出した補正値で焦点検出
信号のゲインを一定に補正した信号をフィードバック信
号としてフォーカスサーボをかけるため、観察するパタ
ーンに影響されずに制御性のよい自動焦点合わせができ
るという効果を奏する。According to the microscope auto-focusing apparatus of the present invention, the focus servo is performed by using the focus detection signal obtained by differentially amplifying the focus degree values of the image signals from the two image pickup means arranged before and after the focus position as a feedback signal. Instead of multiplying, a signal in which the gain of the focus detection signal is constantly corrected with a correction value calculated based on the in-focus position and the in-focus degree values of the image signals from the three image pickup units arranged before and after the in-focus position is used. for applying the focus servo as a feedback signal, that Sosu the effect that it is good autofocus controllability without being influenced by the pattern observation.
【図１】本発明の一実施例を示す構成図である。FIG. 1 is a configuration diagram showing an embodiment of the present invention.
【図２】図１，図５，図６中の合焦度検出手段の内部ブ
ロック図である。FIG. 2 is an internal block diagram of focusing degree detection means in FIGS . 1 , 5 and 6. FIG.
【図３】図１，図５，図６中の焦点位置による合焦度信
号ｂ2 〜ｂ3 の変化を示す図である。FIG. 3 is a diagram showing changes in focus degree signals b2 to b3 depending on the focus position in FIGS . 1 , 5 and 6;
【図４】図１，図５，図６中の焦点位置による焦点検出
信号ｃの変化を示す図である。FIG. 4 is a diagram showing changes in the focus detection signal c depending on the focus position in FIGS . 1 , 5 and 6.
【図５】本発明の別の実施例を示す構成図である。FIG. 5 is a configuration diagram showing another embodiment of the present invention.
【図６】従来の一例を示す構成図である。FIG. 6 is a configuration diagram showing a conventional example.
１ 上下ステージ ２ 試料 ３ 対物レンズ ４１ 観察光軸 ４２ 焦点検出光軸 ５ ハーフミラー ６１ 合焦点ラインセンサ ６２ 前焦点ラインセンサ ６３ 後焦点ラインセンサ ７ 全反射ミラー ８ ５０％ＮＤフィルタ ９ 合焦度検出手段 ９１ 微分回路 ９２ 積分回路 １０ 差動アンプ １１ 補正値演算手段 １２ 乗算回路 １３ 結像レンズ1 Upper and lower stage 2 Sample 3 Objective lens 41 Observation optical axis 42 Focus detection optical axis 5 Half mirror 61 Focusing line sensor 62 Front focus line sensor 63 Rear focus line sensor 7 Total reflection mirror 8 50% ND filter 9 Focusing degree detecting means 91 Differentiating circuit 92 Integrating circuit 10 Differential Amplifier 11 Correction value calculation means 12 Multiplier circuit 13 Imaging lens
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｇ０３Ｂ 3/00 Ａ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical display location G03B 3/00 A
Claims (7)
の焦点検出光軸とに分割する光分割器と、前記３本の各
焦点検出光軸上にあって、合焦時の対物レンズによる実
像位置と、観察対象が合焦位置から所定量だけ前焦点側
および後焦点側にずれたときの前記対物レンズによる実
像位置とに配置された３個の撮像手段と、前記撮像手段
のそれぞれから出力される画像信号をもとに合焦度を検
出して合焦度信号を出力する３個の合焦度検出手段と、
前焦点側と後焦点側の２つの合焦度信号の差動増幅を行
う差動アンプと、前記３個の合焦度検出手段からそれぞ
れ出力される３つの合焦度信号をもとに補正信号を演算
して出力する補正値演算手段と、前記差動アンプと前記
補正値演算手段との出力信号を乗算して焦点検出信号を
出力する乗算回路とを含むことを特徴とする顕微鏡自動
焦点装置。1. An optical splitter for splitting an image forming optical axis of an optical microscope into an observation optical axis and three focus detecting optical axes, and an optical splitter on each of the three focus detecting optical axes, which is used for focusing. Image pickup means arranged at the real image position by the objective lens and the real image position by the objective lens when the observation target is deviated from the focus position to the front focus side and the rear focus side by a predetermined amount, and the image pickup means. Three focus degree detecting means for detecting the focus degree based on the image signal output from each of the means and outputting the focus degree signal;
Correction is performed based on a differential amplifier that differentially amplifies two focus degree signals on the front focus side and the rear focus side, and three focus degree signals respectively output from the three focus degree detecting means. A microscope automatic focus, comprising: a correction value calculation means for calculating and outputting a signal; and a multiplication circuit for multiplying the output signals of the differential amplifier and the correction value calculation means and outputting a focus detection signal. apparatus.
顕微鏡の光軸上にあって対物レンズの次段に配置されて
実像をつくる結像レンズを含むことを特徴とする、請求
項１記載の顕微鏡自動焦点装置。2. The optical microscope is an infinite optical system,
2. The microscope auto-focusing device according to claim 1, further comprising an image forming lens which is arranged on the optical axis of the microscope and which is arranged next to the objective lens to form a real image.
手段であることを特徴とする、請求項１または請求項２
記載の顕微鏡自動焦点装置。3. The image pickup means is a means using a line sensor, wherein the image pickup means is a means using a line sensor.
The described microscope autofocus device.
手段であることを特徴とする、請求項１または請求項２
記載の顕微鏡自動焦点装置。4. The image pickup means is a means using a two-dimensional sensor, according to claim 1 or 2.
The described microscope autofocus device.
の絶対値を検出する手段であることを特徴とする、請求
項１，請求項２，請求項３，または請求項４記載の顕微
鏡自動焦点装置。5. The focusing degree detecting means is means for detecting an absolute value of a differential value of an image signal, according to claim 1, claim 2, claim 3, or claim 4. Microscope autofocus device.
散値を検出する手段であることを特徴とする、請求項
１，請求項２，請求項３，または請求項４記載の顕微鏡
自動焦点装置。6. The automatic microscope according to claim 1, wherein the focus degree detecting means is means for detecting a luminance dispersion value of an image signal. Focus device.
換像の高次成分量を検出する手段であることを特徴とす
る、請求項１，請求項２，請求項３，または請求項４記
載の顕微鏡自動焦点装置。7. The in-focus degree detecting means is means for detecting a higher-order component amount of an orthogonal transformation image of an image signal, claim 1, claim 2, claim 3, or claim. 4. The automatic microscope focusing device described in 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29284594A JPH08152550A (en) | 1994-11-28 | 1994-11-28 | Automatic focusing device of microscope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29284594A JPH08152550A (en) | 1994-11-28 | 1994-11-28 | Automatic focusing device of microscope |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08152550A true JPH08152550A (en) | 1996-06-11 |
Family
ID=17787114
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29284594A Pending JPH08152550A (en) | 1994-11-28 | 1994-11-28 | Automatic focusing device of microscope |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08152550A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002099497A1 (en) * | 2001-06-04 | 2002-12-12 | Fuji Photo Optical Co., Ltd. | Device for determining focused state of taking lens |
| FR2843809A1 (en) * | 2002-08-23 | 2004-02-27 | Fuji Photo Optical Co Ltd | Picture-taking lens focus controlling system for video camera, has focus evaluation value generation device generating value indicating degree of sharpness of image and corrector correcting sensitivity of evaluation value |
| JP2007264151A (en) * | 2006-03-28 | 2007-10-11 | Sysmex Corp | Sample imaging apparatus and sample analyzing apparatus equipped with the same |
| US7576796B2 (en) | 2002-08-23 | 2009-08-18 | Fujinon Corporation | Auto focus system |
| JP2014085217A (en) * | 2012-10-23 | 2014-05-12 | Nuflare Technology Inc | Focus position detection device, inspection device, focus position detection method and inspection method |
| KR20220008044A (en) * | 2020-07-13 | 2022-01-20 | 주식회사 에타맥스 | Automatic Optical Focus Control Device and Optical Instrument Comprising The Same |
| JP2022071162A (en) * | 2018-03-14 | 2022-05-13 | ナノトロニクス イメージング インコーポレイテッド | System, device, and method for automatic microscopic focus |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS595214A (en) * | 1982-07-02 | 1984-01-12 | Toshiba Corp | Automatic focusing device |
-
1994
- 1994-11-28 JP JP29284594A patent/JPH08152550A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS595214A (en) * | 1982-07-02 | 1984-01-12 | Toshiba Corp | Automatic focusing device |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002099497A1 (en) * | 2001-06-04 | 2002-12-12 | Fuji Photo Optical Co., Ltd. | Device for determining focused state of taking lens |
| US6833538B2 (en) | 2001-06-04 | 2004-12-21 | Fuji Photo Optical Co., Ltd. | Device for determining focused state of taking lens |
| FR2843809A1 (en) * | 2002-08-23 | 2004-02-27 | Fuji Photo Optical Co Ltd | Picture-taking lens focus controlling system for video camera, has focus evaluation value generation device generating value indicating degree of sharpness of image and corrector correcting sensitivity of evaluation value |
| US7345706B2 (en) | 2002-08-23 | 2008-03-18 | Fuji Photo Optical Co., Ltd. | Auto focus system |
| US7576796B2 (en) | 2002-08-23 | 2009-08-18 | Fujinon Corporation | Auto focus system |
| DE10338249B4 (en) * | 2002-08-23 | 2014-01-23 | Fujifilm Corporation | Autofocus device using the ratio of two focus evaluation values at positions of different optical path lengths |
| JP2007264151A (en) * | 2006-03-28 | 2007-10-11 | Sysmex Corp | Sample imaging apparatus and sample analyzing apparatus equipped with the same |
| JP2014085217A (en) * | 2012-10-23 | 2014-05-12 | Nuflare Technology Inc | Focus position detection device, inspection device, focus position detection method and inspection method |
| US9557277B2 (en) | 2012-10-23 | 2017-01-31 | Nuflare Technology, Inc. | Inspection apparatus and inspection method |
| JP2022071162A (en) * | 2018-03-14 | 2022-05-13 | ナノトロニクス イメージング インコーポレイテッド | System, device, and method for automatic microscopic focus |
| KR20220008044A (en) * | 2020-07-13 | 2022-01-20 | 주식회사 에타맥스 | Automatic Optical Focus Control Device and Optical Instrument Comprising The Same |
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