JPH04223450A - Light quantity controller - Google Patents
Light quantity controllerInfo
- Publication number
- JPH04223450A JPH04223450A JP2419082A JP41908290A JPH04223450A JP H04223450 A JPH04223450 A JP H04223450A JP 2419082 A JP2419082 A JP 2419082A JP 41908290 A JP41908290 A JP 41908290A JP H04223450 A JPH04223450 A JP H04223450A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- change
- light amount
- rate
- aperture
- 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
- 238000001514 detection method Methods 0.000 claims description 33
- 230000006698 induction Effects 0.000 abstract 2
- 238000010586 diagram Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 3
- 230000004069 differentiation Effects 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 1
Landscapes
- Exposure Control For Cameras (AREA)
- Diaphragms For Cameras (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、ビデオカメラ等の撮影
装置及び光学機器に搭載される光量制御装置に関するも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light amount control device mounted on a photographing device such as a video camera and an optical device.
【０００２】0002
【従来の技術】従来、光量制御装置として図７乃至図８
に示すような制御計の装置が提案されている。図７は従
来公知の光量制御装置の制御回路の主要構成を示す回路
ブロック図で、光量制御部材を駆動させるためのモータ
部３が、光量制御信号と速度制御信号を比較する差動ア
ンプ１より出力される速度誤差信号をモータ駆動信号に
する電力アンプ２からの出力によりマグネットロータ５
を回転させるための駆動コイル４と、光量制御部材を駆
動させるマグネットロータ５と、該マグネットロータ５
の回転速度を検知する制動コイル６を有し、かつ該マグ
ネットロータ５の位置を検出する磁気感応素子７を備え
ている。該制動コイル６からの出力信号は信号アンプ９
を介して速度制御信号として前記差動アンプ１に入力さ
れ、該磁気感応素子７から出たリニアな位置検出信号を
差動アンプ８を介してリニアな絞り値検出信号にして出
力するようになっていた。[Prior Art] Conventionally, as a light amount control device, FIGS.
A controller device as shown in Figure 1 has been proposed. FIG. 7 is a circuit block diagram showing the main configuration of a control circuit of a conventionally known light amount control device, in which a motor section 3 for driving a light amount control member is connected to a differential amplifier 1 for comparing a light amount control signal and a speed control signal. The output from the power amplifier 2 converts the output speed error signal into a motor drive signal, which drives the magnet rotor 5.
a drive coil 4 for rotating the light amount control member; a magnet rotor 5 for driving the light amount control member;
It has a braking coil 6 that detects the rotational speed of the magnet rotor 5, and a magnetic sensing element 7 that detects the position of the magnet rotor 5. The output signal from the braking coil 6 is sent to a signal amplifier 9.
The linear position detection signal outputted from the magnetic sensing element 7 is input as a speed control signal to the differential amplifier 1 via the differential amplifier 8, and is output as a linear aperture value detection signal. was.
【０００３】図８は本出願人の既に提案している光量制
御装置の制御回路の主要構成を示す回路ブロック図で、
光量制御部材を駆動させるためのモータ部１３が、光量
制御信号と速度制御信号を比較する差動アンプ１１より
出力される速度誤差信号をモータ駆動信号にする電力ア
ンプ１２からの出力によりマグネットロータ１５を回転
させるための駆動コイル１４と、光量制御部材を駆動さ
せる該マグネットロータ１５を有し、かつ該マグネット
ロータ１５の位置を検出する磁気感応素子１７を備えて
いる。該磁気感応素子１７から出力されるリニアな位置
検出信号を差動アンプ１８を介してリニアな絞り値検出
信号にして出力し、該リニアな絞り値検出信号を微分回
路１９によって速度制御信号に変換し、前記差動アンプ
１１に入力されるようになっていた。FIG. 8 is a circuit block diagram showing the main configuration of a control circuit of a light amount control device already proposed by the present applicant.
The motor section 13 for driving the light amount control member drives the magnet rotor 15 by using the output from the power amplifier 12 which converts the speed error signal outputted from the differential amplifier 11, which compares the light amount control signal and the speed control signal, into a motor drive signal. It has a drive coil 14 for rotating the light amount control member, a magnet rotor 15 for driving the light amount control member, and a magnetic sensing element 17 for detecting the position of the magnet rotor 15. The linear position detection signal output from the magnetic sensing element 17 is output as a linear aperture value detection signal via a differential amplifier 18, and the linear aperture value detection signal is converted into a speed control signal by a differentiating circuit 19. However, the signal was input to the differential amplifier 11.
【０００４】0004
【発明が解決しようとする課題】しかしながら、上記従
来例では、速度制御信号はマグネットロータの回転速度
に比例した出力となり、単位時間あたりの開口面積（絞
り値）の変化率に対して比例したものではない。したが
ってマグネットロータの回転速度に対して一定の強さで
速度制御がかかるが、本来の制御の目的である光量の単
位時間あたりの変化率に対して不均一な速度制御となる
。すなわち光量の変化に対して、上記従来例の速度制御
では、光量制御部材の動作は、大口径（開放側）で必要
以上に遅くなり、小口径（小絞り側）では速すぎるもの
となる。このような制御では過大光量時に小絞り側でハ
ンチングが発生しやすく、また開放から小絞りまでの応
答時間が不適切に遅くなる欠点があった。[Problems to be Solved by the Invention] However, in the above conventional example, the speed control signal is an output proportional to the rotational speed of the magnet rotor, and is proportional to the rate of change of the aperture area (aperture value) per unit time. isn't it. Therefore, although the rotational speed of the magnet rotor is controlled with a constant strength, the speed control becomes non-uniform with respect to the rate of change of the amount of light per unit time, which is the original purpose of control. In other words, in the speed control of the conventional example described above, the operation of the light amount control member becomes unnecessarily slow at large apertures (on the open side) and too fast at small apertures (on the small aperture side) with respect to changes in the amount of light. This type of control has the disadvantage that hunting tends to occur on the small aperture side when the amount of light is excessive, and the response time from opening to the small aperture becomes inappropriately slow.
【０００５】また上記従来例では、絞り値検出信号はマ
グネットロータの駆動量に比例したリニアな位置検出信
号であり、開口面積の変化率に比例したものではない。
したがって小絞り側の絞り値検出精度が非常に悪くなる
欠点があった。Furthermore, in the conventional example described above, the aperture value detection signal is a linear position detection signal that is proportional to the amount of drive of the magnet rotor, and is not proportional to the rate of change of the aperture area. Therefore, there is a drawback that the aperture value detection accuracy on the small aperture side becomes extremely poor.
【０００６】本発明はかかる従来の欠点に鑑みてなされ
たもので、光量の変化率に対して常に適切な速度制御を
かけることのできる光量制御装置を提供することを目的
とする。SUMMARY OF THE INVENTION The present invention has been made in view of these conventional drawbacks, and an object of the present invention is to provide a light amount control device that can always perform appropriate speed control on the rate of change in light amount.
【０００７】[0007]
【課題を解決するための手段】本発明の光量制御装置は
請求項１においては単位時間あたりの開口面積の変化率
に比例した速度制御手段を設けたものであり、また、請
求項２においては請求項１に対してさらに開口面積の変
化率に比例した変化率となる絞り値検出手段を設けたも
のである。[Means for Solving the Problems] The light amount control device of the present invention is provided with a speed control means proportional to the rate of change of the aperture area per unit time. The present invention is further provided with an aperture value detection means whose rate of change is proportional to the rate of change of the aperture area.
【０００８】[0008]
【作用】上記手段を設けることにより、光量の変化率に
対して常に適切な速度制御をかけることができ、また、
開口面積の変化率に比例した変化率となるリニアな絞り
値検出手段を設けることにより、絞り値検出精度を均一
化することができる。[Operation] By providing the above means, it is possible to always apply appropriate speed control to the rate of change in the amount of light, and
By providing a linear aperture value detection means whose rate of change is proportional to the rate of change in the aperture area, the aperture value detection accuracy can be made uniform.
【０００９】[0009]
【実施例】以下、本発明の一実施例を図１〜図６に基づ
いて説明する。図１は本実施例の光量制御装置の制御部
の概略構成を示す回路図で、同図において２１は光量制
御信号と速度制御信号を比較する差動アンプ、２２は該
差動アンプ２１から出力された速度誤差信号をマグネッ
トロータ２５を駆動するための信号にする電力アンプ、
２３は駆動コイル２４と該マグネットロータ２５と磁気
感応素子２７とを有し後述の光量制御部材３４、３５を
駆動するためのモータ部、２４は前記電力アンプ２２か
らの出力信号によりマグネットロータ２５を回転させる
駆動コイル、２５は該駆動コイル２４により光量制御部
材３４、３５を駆動するために回転するマグネットロー
タ、２７は該マグネットロータ２５の位置をリニアに検
出する磁気感応素子、２８は該磁気感応素子２７の出力
を決められたリニアな値にアンプ調整する差動アンプ、
２９は関数発生器３０のリニアな出力を速度制御信号に
変換する微分回路、３０は差動アンプ２８のリニアな位
置検出信号を開口面積の変化率に比例した変化率となる
位置検出信号に改善して絞り値検出信号として出力する
関数発生器ある。DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. FIG. 1 is a circuit diagram showing a schematic configuration of the control section of the light amount control device of this embodiment. In the same figure, 21 is a differential amplifier that compares the light amount control signal and the speed control signal, and 22 is the output from the differential amplifier 21. a power amplifier that converts the speed error signal into a signal for driving the magnet rotor 25;
Reference numeral 23 denotes a motor section that includes a drive coil 24, the magnet rotor 25, and a magnetically sensitive element 27, and drives light quantity control members 34 and 35, which will be described later. 25 is a magnet rotor that rotates to drive the light quantity control members 34 and 35 by the drive coil 24; 27 is a magnetic sensing element that linearly detects the position of the magnet rotor 25; 28 is a magnetic sensing element that linearly detects the position of the magnet rotor 25; a differential amplifier that adjusts the output of the element 27 to a predetermined linear value;
29 is a differentiation circuit that converts the linear output of the function generator 30 into a speed control signal, and 30 is a differential amplifier 28 that improves the linear position detection signal to a position detection signal whose rate of change is proportional to the rate of change of the aperture area. There is a function generator that outputs the aperture value detection signal as an aperture value detection signal.
【００１０】図２は、本実施例における光量制御装置の
分解斜視図を示す。同図において、２３は前記モータ部
、３１は該モータ部２３を支持しかつ他面側に光量制御
部材３４、３５を支持する絞り地板で、開口部を有して
いる。３２は該モータ部２３の駆動力を前記光量制御部
材３４、３５に伝達する駆動アーム、３３は光量制御部
材３４、３５を常に閉じ方向に付勢するバネ、３４、３
５は光量を制御する光量制御部材、３６は該光量制御部
材３４、３５を収納するためのカバーであり、開口部３
７を有している。FIG. 2 shows an exploded perspective view of the light amount control device in this embodiment. In the figure, 23 is the motor section, and 31 is an aperture base plate that supports the motor section 23 and supports light amount control members 34 and 35 on the other side, and has an opening. 32 is a drive arm that transmits the driving force of the motor section 23 to the light amount control members 34, 35; 33 is a spring that always biases the light amount control members 34, 35 in the closing direction; 34, 3;
5 is a light amount control member for controlling the amount of light; 36 is a cover for housing the light amount control members 34 and 35;
7.
【００１１】以上の構成において、まず光量制御信号が
差動アンプ２１、電力アンプ２２を通り駆動コイル２４
に通電されてマグネットロータ２５が回転し、光量制御
部材３４、３５を駆動する。このマグネットロータ２５
の回転位置を磁気感応素子２７がリニアに検知し、磁気
感応素子２７の出力信号は差動アンプ２８を通って関数
発生器３０に決められたリニアな位置検出信号として入
力される。関数発生器３０では決められたリニアな位置
検出信号を図３や図４に示すＶ０のような開口面積の変
化率に比例したリニアな位置検出信号に変換し、絞り値
検出信号として出力する。In the above configuration, the light amount control signal first passes through the differential amplifier 21 and the power amplifier 22 to the drive coil 24.
The magnet rotor 25 is energized to rotate and drive the light amount control members 34 and 35. This magnet rotor 25
The magnetically sensitive element 27 linearly detects the rotational position of the magnetically sensitive element 27, and the output signal of the magnetically sensitive element 27 is inputted to the function generator 30 as a determined linear position detection signal through the differential amplifier 28. The function generator 30 converts the determined linear position detection signal into a linear position detection signal proportional to the rate of change of the aperture area, such as V0 shown in FIGS. 3 and 4, and outputs it as an aperture value detection signal.
【００１２】この開口面積の変化率に対してリニアな絞
り値検出信号は微分回路２９に入力され、そのリニアな
絞り値検出信号の傾きに比例した速度制御信号、すなわ
ち、図５や図６に示すような単位時間あたりの開口面積
の変化率に比例して速度制御信号を出力する。この速度
制御信号は、差動アンプ２１に入力され、差動アンプ２
１により光量制御信号と比較され、光量制御信号の急激
な変化を押さえるように速度誤差信号として出力される
。速度誤差信号は電力アンプ２２を通り駆動コイル２４
に通電されてマグネットロータ２５を回転させ、光量制
御部材３４、３５を駆動して、適切な光量にすばやく安
定させる。特に速度制御信号は関数発生器３０と微分回
路２９によりマグネットロータ２５の回転速度ではなく
単位時間あたりの開口面積の変化率すなわち本来の制御
目的である単位時間あたりの光量の変化率に比例した出
力となり、常に適切な速度制御となる。The aperture value detection signal linear with respect to the rate of change of the aperture area is input to a differentiating circuit 29, which generates a speed control signal proportional to the slope of the linear aperture value detection signal, that is, as shown in FIGS. 5 and 6. A speed control signal is output in proportion to the rate of change in the opening area per unit time as shown. This speed control signal is input to the differential amplifier 21, and the differential amplifier 2
1 is compared with the light amount control signal and output as a speed error signal so as to suppress sudden changes in the light amount control signal. The speed error signal passes through the power amplifier 22 and the drive coil 24.
is energized to rotate the magnet rotor 25, drive the light quantity control members 34 and 35, and quickly stabilize the light quantity to an appropriate level. In particular, the speed control signal is output by the function generator 30 and the differentiation circuit 29, which is proportional to the rate of change in the aperture area per unit time, rather than the rotational speed of the magnet rotor 25, which is the original control purpose. Therefore, appropriate speed control is always achieved.
【００１３】図３は光量制御装置の光量制御部材が閉じ
位置から開放まで開口面積変化率ｄｓ／ｓを一定で動い
たときの位置検出信号（絞り値検出信号）を表したもの
で、Ｖ０は本実施例の絞り値検出信号であり、Ｖ１は従
来例の絞り値検出信号である。横軸の開口面積の底２の
対数は、等間隔の目盛りに対して開口面積変化率ｄｓ／
ｓが一定となるものである。ここで、本実施例のＶ０は
開口面積変化率に対して比例した変化率（傾き一定）と
なるように従来例Ｖ１を改善しているのがわかる。FIG. 3 shows the position detection signal (aperture value detection signal) when the light quantity control member of the light quantity control device moves from the closed position to the open position at a constant aperture area change rate ds/s, and V0 is This is the aperture value detection signal of this embodiment, and V1 is the aperture value detection signal of the conventional example. The base 2 logarithm of the aperture area on the horizontal axis is the aperture area change rate ds/ with respect to equally spaced scales.
s is constant. Here, it can be seen that the conventional example V1 is improved so that V0 of this embodiment has a rate of change (constant slope) proportional to the rate of change of the opening area.
【００１４】図４は図３のｄｓ／ｓ一定をマグネットロ
ータ回転角度変化率ｄθ／θ一定とした場合の位置検出
信号（絞り値検出信号）を表したもので、従来例の絞り
値検出信号であるＶ１は回転角度変化率ｄθ／θに対し
て比例した変化率（傾き一定）となっているのがわかる
。FIG. 4 shows a position detection signal (aperture value detection signal) when the constant ds/s shown in FIG. It can be seen that V1 has a rate of change (constant slope) proportional to the rotational angle change rate dθ/θ.
【００１５】図５は図３のｄｓ／ｓ一定から単位時間あ
たりの開口面積変化率ｄｓ／ｓ・ｄ／ｄｔ一定として動
作させた場合の速度制御信号を表したもので、Ｖ１は本
実施例の速度制御信号であり、Ｖ２は従来例の速度制御
信号である。ここで本実施例のＶ１は単位時間あたりの
開口面積変化率ｄｓ／ｓ・ｄ／ｄｔ一定に対して一定の
出力となるように従来例のＶ２を改善していいるのがわ
かる。FIG. 5 shows the speed control signal when operating from constant ds/s in FIG. 3 to constant aperture area change rate ds/s·d/dt per unit time, and V1 is the speed control signal of this embodiment. V2 is the speed control signal of the conventional example. Here, it can be seen that V1 of this embodiment is an improvement over V2 of the conventional example so that the output is constant for a constant aperture area change rate ds/s·d/dt per unit time.
【００１６】図６は図５のｄｓ／ｓ・ｄ／ｄｔ一定をマ
グネットロータの回転速度ｄθ／ｄｔ一定として動作さ
せた場合の速度制御信号であり、従来例のＶ２はマグネ
ットロータの回転速度ｄθ／ｄｔ一定に対して一定の出
力となっているのがわかる。FIG. 6 shows a speed control signal when the constant ds/s・d/dt shown in FIG. 5 is operated with the rotational speed dθ/dt of the magnet rotor constant, and V2 in the conventional example is the rotational speed dθ of the magnet rotor. It can be seen that the output is constant for a constant /dt.
【００１７】[0017]
【発明の効果】以上説明したように、本発明は単位時間
あたりの開口面積の変化率に比例した速度制御を行うこ
とにより、光量の変化に対して常に適切な速度制御をか
けることができるため、過大光量時に起きる小絞り側の
ハンチングをわずかに押さえ、開放から小絞りまでの応
答速度を高速にすることができ、安定で高速・高精度な
光量制御が実現できる効果がある。[Effects of the Invention] As explained above, the present invention can always apply appropriate speed control to changes in the amount of light by performing speed control proportional to the rate of change of the aperture area per unit time. This has the effect of slightly suppressing hunting on the small aperture side that occurs when the amount of light is excessive, increasing the response speed from the aperture to the small aperture, and realizing stable, high-speed, and highly accurate light amount control.
【００１８】また、開口面積の変化率に比例した変化率
となる位置検出信号により、小絞り側の絞り値検出精度
を上げることで、絞り値情報を使用するオートフォーカ
ス精度やインテリジェントオートアイリスの絞り補正精
度に寄与する。特にマニュアル絞りにおいては、小絞り
側の高精度な絞り値検出信号と共に小絞り側の制御の安
定性がマニュアル絞りの小絞り側を高精度に位置決めす
る効果がある。Furthermore, by increasing the aperture value detection accuracy on the small aperture side using a position detection signal whose rate of change is proportional to the rate of change in the aperture area, autofocus accuracy using aperture value information and aperture correction of intelligent auto iris can be improved. Contributes to accuracy. Particularly in a manual aperture, a highly accurate aperture value detection signal on the small aperture side and stability of control on the small aperture side have the effect of positioning the small aperture side of the manual aperture with high precision.
【図１】本実施例の光量制御装置の制御部の概略構成を
示す回路図である。FIG. 1 is a circuit diagram showing a schematic configuration of a control section of a light amount control device according to an embodiment.
【図２】本実施例における光量制御装置の分解斜視図で
ある。FIG. 2 is an exploded perspective view of the light amount control device in this embodiment.
【図３】開口面積変化率を一定とした場合の位置検出信
号グラフである。FIG. 3 is a position detection signal graph when the aperture area change rate is constant.
【図４】マグネットロータの回転角変化率を一定とした
場合の位置検出信号グラフである。FIG. 4 is a position detection signal graph when the rate of change in rotation angle of the magnet rotor is constant.
【図５】単位時間あたりの開口面積変化率を一定とした
場合の速度制御信号グラフである。FIG. 5 is a speed control signal graph when the aperture area change rate per unit time is constant.
【図６】マグネットロータの回転速度を一定とした場合
の速度制御信号グラフである。FIG. 6 is a speed control signal graph when the rotational speed of the magnet rotor is constant.
【図７】従来公知の光量制御装置の制御回路の主要構成
を示す回路ブロック図である。FIG. 7 is a circuit block diagram showing the main configuration of a control circuit of a conventionally known light amount control device.
【図８】本出願人の既に提案している光量制御装置の制
御回路の主要構成を示す回路ブロック図である。FIG. 8 is a circuit block diagram showing the main configuration of a control circuit of a light amount control device already proposed by the present applicant.
２１ 差動アンプ ２２ 電力アンプ ２３ モータ部 ２４ 駆動コイル ２５ マグネットロータ ２７ 磁気感応素子 ２８ 差動アンプ ２９ 微分回路 ３０ 関数発生器 ３４、３５ 光量制御部材 21 Differential amplifier 22 Power amplifier 23 Motor part 24 Drive coil 25 Magnet rotor 27 Magnetic sensing element 28 Differential amplifier 29 Differential circuit 30 Function generator 34, 35 Light amount control member
Claims (2)
率に比例した速度制御手段を設けたことを特徴とする光
量制御装置。1. A light amount control device comprising a speed control means proportional to the rate of change of the aperture area per unit time.
率となる絞り値検出手段を設けたことを特徴とする請求
項１の光量制御装置。2. The light amount control device according to claim 1, further comprising aperture value detection means whose rate of change is proportional to the rate of change of the aperture area.
Priority Applications (9)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2419082A JP2571982B2 (en) | 1990-12-25 | 1990-12-25 | Light amount control device and optical apparatus having light amount control device |
| CA002058396A CA2058396C (en) | 1990-12-25 | 1991-12-23 | Light-quantity control device |
| DE69131039T DE69131039T2 (en) | 1990-12-25 | 1991-12-24 | Device for controlling the amount of light |
| EP91122211A EP0492617B1 (en) | 1990-12-25 | 1991-12-24 | Light-quantity control device |
| EP95118783A EP0708358B1 (en) | 1990-12-25 | 1991-12-24 | Light-quantity control device |
| DE69132075T DE69132075T2 (en) | 1990-12-25 | 1991-12-24 | Device for controlling the amount of light |
| US08/409,541 US5646769A (en) | 1990-12-25 | 1995-03-24 | Light-quantity control device |
| US08/417,826 US5646770A (en) | 1990-12-25 | 1995-04-06 | Light-quantity control device |
| US08/417,829 US5749015A (en) | 1990-12-25 | 1995-04-06 | Light-quantity control device with spring control of light control member |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2419082A JP2571982B2 (en) | 1990-12-25 | 1990-12-25 | Light amount control device and optical apparatus having light amount control device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04223450A true JPH04223450A (en) | 1992-08-13 |
| JP2571982B2 JP2571982B2 (en) | 1997-01-16 |
Family
ID=18526788
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2419082A Expired - Lifetime JP2571982B2 (en) | 1990-12-25 | 1990-12-25 | Light amount control device and optical apparatus having light amount control device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2571982B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7394497B2 (en) | 2003-03-27 | 2008-07-01 | Fujifilm Corporation | Camera with variable aperture member |
| JP2010015137A (en) * | 2008-05-16 | 2010-01-21 | Panasonic Corp | Interchangeable lens, camera body and camera system |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0466921A (en) * | 1990-07-04 | 1992-03-03 | Sony Corp | Video camera |
-
1990
- 1990-12-25 JP JP2419082A patent/JP2571982B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0466921A (en) * | 1990-07-04 | 1992-03-03 | Sony Corp | Video camera |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7394497B2 (en) | 2003-03-27 | 2008-07-01 | Fujifilm Corporation | Camera with variable aperture member |
| JP2010015137A (en) * | 2008-05-16 | 2010-01-21 | Panasonic Corp | Interchangeable lens, camera body and camera system |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2571982B2 (en) | 1997-01-16 |
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