JPH11112849A - Imaging device using CCD camera - Google Patents
Imaging device using CCD cameraInfo
- Publication number
- JPH11112849A JPH11112849A JP9276160A JP27616097A JPH11112849A JP H11112849 A JPH11112849 A JP H11112849A JP 9276160 A JP9276160 A JP 9276160A JP 27616097 A JP27616097 A JP 27616097A JP H11112849 A JPH11112849 A JP H11112849A
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- light
- shutter
- scatter
- ccd camera
- 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.)
- Pending
Links
- 238000003384 imaging method Methods 0.000 title claims description 9
- 239000004973 liquid crystal related substance Substances 0.000 claims abstract description 40
- 230000003287 optical effect Effects 0.000 claims abstract description 9
- 230000005540 biological transmission Effects 0.000 claims description 13
- 238000002834 transmittance Methods 0.000 abstract description 8
- 238000010791 quenching Methods 0.000 abstract 1
- 230000000171 quenching effect Effects 0.000 abstract 1
- 230000000007 visual effect Effects 0.000 abstract 1
- 239000005262 ferroelectric liquid crystals (FLCs) Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- WLPATYNQCGVFFH-UHFFFAOYSA-N 2-phenylbenzonitrile Chemical group N#CC1=CC=CC=C1C1=CC=CC=C1 WLPATYNQCGVFFH-UHFFFAOYSA-N 0.000 description 1
- 238000000149 argon plasma sintering Methods 0.000 description 1
- 230000008033 biological extinction Effects 0.000 description 1
- 230000000740 bleeding effect Effects 0.000 description 1
- 239000004815 dispersion polymer Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Landscapes
- Liquid Crystal (AREA)
- Transforming Light Signals Into Electric Signals (AREA)
- Studio Devices (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ＣＣＤイメージセ
ンサを内蔵するＣＣＤカメラを用いた撮像装置に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus using a CCD camera having a built-in CCD image sensor.
【０００２】[0002]
【従来の技術】ＣＣＤカメラとはＣＣＤイメージセンサ
を利用したカメラをいい、ＣＣＤイメージセンサは、通
常、フォトダイオードと、フォトダイオードに発生した
電荷を転送する電荷結合素子（ＣＣＤ）とからなる。2. Description of the Related Art A CCD camera refers to a camera using a CCD image sensor. The CCD image sensor generally includes a photodiode and a charge-coupled device (CCD) for transferring charges generated in the photodiode.
【０００３】[0003]
【発明が解決しようとする課題】ＣＣＤカメラを用いて
撮像するときに、フォトダイオードの信号電荷が垂直転
送路に漏れることによるスミア（高輝度被写体の再生像
の上下に現れる光のにじみ）が原因で高精細な撮像情報
が得られないという問題がある。そこでスミアを低減す
る方策として、機械式シャッターを設けることが知られ
ているが、故障が多く耐久性の点で問題がある。When an image is picked up using a CCD camera, signal charges of a photodiode leak into a vertical transfer path, resulting in smear (light bleeding above and below a reproduced image of a high-luminance object). However, there is a problem that high-definition imaging information cannot be obtained. Therefore, it is known to provide a mechanical shutter as a measure to reduce smear, but there are many failures and there is a problem in durability.
【０００４】最近になって、ＴＮ型液晶、強誘電性液
晶、半強誘電性液晶シャッターを使用することも行われ
ているが、ＴＮ型液晶シャッターは光透過率が低く、カ
メラの感度が低下するという問題がある。強誘電性液晶
や半強誘電性液晶シャッターは、波長帯域が狭く、波長
依存性が大きくカメラ感度が低いという問題がある。そ
こで、本発明は、光透過率が高く、波長帯域幅が広く、
スミアを効率的に低減することができる信頼性の高いＣ
ＣＤカメラを用いた撮像を実現することを目的とする。Recently, a TN type liquid crystal, a ferroelectric liquid crystal, and a semi-ferroelectric liquid crystal shutter have been used. However, the TN type liquid crystal shutter has a low light transmittance and lowers the sensitivity of a camera. There is a problem of doing. Ferroelectric liquid crystal and semi-ferroelectric liquid crystal shutters have a problem that the wavelength band is narrow, the wavelength dependence is large, and the camera sensitivity is low. Therefore, the present invention has a high light transmittance, a wide wavelength bandwidth,
Highly reliable C that can efficiently reduce smear
An object is to realize imaging using a CD camera.
【０００５】[0005]
【課題を解決するための手段】本発明のＣＣＤカメラを
用いた撮像は、ＣＣＤカメラに入射する光をオンオフす
るシャッターとして、ＣＣＤイメージセンサの電子シャ
ッターと同期して作動する透過散乱型の液晶シャッター
を用いている。透過散乱型液晶は、電圧を印加しないと
きには光を散乱し、電圧を印加すると透明になるという
機能を有する。本発明では、この透過散乱型液晶を用い
てシャッターを構成するので、光透過率が高く、波長帯
域幅が広いという透過散乱型液晶の特徴を生かした撮像
装置を実現することができる。In the imaging using the CCD camera of the present invention, a transmission / scattering type liquid crystal shutter which operates in synchronization with an electronic shutter of a CCD image sensor is used as a shutter for turning on / off light incident on the CCD camera. Is used. The transmission scattering type liquid crystal has a function of scattering light when no voltage is applied and becoming transparent when a voltage is applied. In the present invention, since the shutter is formed using the transmission scattering type liquid crystal, it is possible to realize an image pickup apparatus utilizing the characteristics of the transmission scattering type liquid crystal having a high light transmittance and a wide wavelength bandwidth.
【０００６】前記ＣＣＤカメラと液晶シャッターとを、
シュリーレン光学系に配置している場合は、シュリーレ
ン光学系における絞りの開口を調節することによって、
電圧無印加時の散乱状態の散乱率を高くすることができ
る。[0006] The CCD camera and the liquid crystal shutter are
When arranged in the Schlieren optical system, by adjusting the aperture of the stop in the Schlieren optical system,
The scattering rate in the scattering state when no voltage is applied can be increased.
【０００７】[0007]
【発明の実施の形態】以下、本発明の実施の形態を、添
付図面を参照しながら詳細に説明する。図１は、シュリ
ーレン光学系に配置された本発明の撮像装置を示す図で
ある。ＣＣＤカメラ２の前には、絞り４、レンズ３及び
液晶シャッター１がこの順に置かれ、絞り４とレンズ３
との距離及びレンズ３と液晶シャッター１との距離は、
ともにレンズの焦点距離ｆとなっている。Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing an imaging device of the present invention arranged in a Schlieren optical system. In front of the CCD camera 2, an aperture 4, a lens 3 and a liquid crystal shutter 1 are placed in this order.
And the distance between the lens 3 and the liquid crystal shutter 1 are
Both are the focal length f of the lens.
【０００８】液晶シャッター１は、透過散乱型液晶に透
明電極１ａ，１ｂを設けたもので、電圧無印加時には光
を散乱させ、電圧印加時には配向が整って光を透過する
特性を有する。透過散乱型液晶材料には、相移転型、ポ
リマー分散型の２つがあるが、どちらのタイプでも使用
することができる（例えば、特開平４−２７８９１５号
公報参照）。The liquid crystal shutter 1 is provided with transparent electrodes 1a and 1b in a transmission scattering type liquid crystal, and has a characteristic of scattering light when no voltage is applied, and has a property of aligning and transmitting light when a voltage is applied. There are two types of transmission scattering type liquid crystal materials, a phase transfer type and a polymer dispersion type. Either type can be used (for example, see JP-A-4-278915).
【０００９】レンズ３から絞り４の開口を見込む角度を
２θ（受光角という）とすると、液晶シャッター１の光
散乱角がこの受光角２θを越える場合に、当該散乱光は
ＣＣＤカメラ２の視野から外れ、検出されないことにな
る。したがって、このシュリーレン光学系を用いて、受
光角２θを調節することにより、所望の消光比を実現す
ることができる。Assuming that the angle at which the aperture of the diaphragm 4 is viewed from the lens 3 is 2θ (referred to as the light-receiving angle), when the light scattering angle of the liquid crystal shutter 1 exceeds the light-receiving angle 2θ, the scattered light is viewed from the field of view of the CCD camera 2. It will come off and will not be detected. Therefore, a desired extinction ratio can be realized by adjusting the light receiving angle 2θ using this Schlieren optical system.
【００１０】前記の撮像装置の使用方法は次のとおりで
ある。被写体を撮像するときに、ＣＣＤカメラ２の電子
シャッターを作動させ、同時に液晶シャッター１に電圧
を印加して被写体からの光を取り込み液晶シャッター１
を閉じる。これによって、液晶シャッター１を開いてい
るときのみ撮像信号情報を取り込み、それ以外では入射
光を散乱させ、実質的に遮光することができる。The method of using the above-mentioned image pickup device is as follows. When capturing an image of a subject, the electronic shutter of the CCD camera 2 is operated, and at the same time, a voltage is applied to the liquid crystal shutter 1 to capture light from the subject and capture the light from the subject.
Close. Thus, the image signal information can be captured only when the liquid crystal shutter 1 is opened, and otherwise, the incident light can be scattered and substantially shielded.
【００１１】この結果、ＣＣＤカメラの撮像面に回り込
んでくる光を抑制し、スミアを低減することができる。As a result, it is possible to suppress the light that enters the imaging surface of the CCD camera and reduce smear.
【００１２】[0012]
【実施例】図１の構成において、印加電圧１００Ｖ（実
効値）の矩形波を用いて液晶シャッター１（メルクジャ
パン社製のシアノビフェニル系液晶、商品名「Ｅ３１Ｌ
Ｖ」）をオンオフすることにより、散乱率ρ（電圧を印
加しない散乱状態の光透過率のこと。液晶シャッター１
がなく空気だけのときの受光強度をＩ0 、液晶シャッタ
ー１を置いて電圧を印加しないときの受光強度をＩ2 と
すると、ρ＝（Ｉ2／Ｉ0 ）×１００％で表される）を
測定したところ、ρ＝１０％という値が得られた。液晶
の応答時間（立ち上がり、立ち下がり時間）は１ｍ秒、
液晶シャッターが透過状態であるときの光透過率（液晶
シャッター１を置いて電圧５０Ｖを印加したときの受光
強度をＩ1 とすると、（Ｉ1 ／Ｉ0 ）×１００％で表さ
れる）は７５％であった。DESCRIPTION OF THE PREFERRED EMBODIMENTS In the configuration of FIG. 1, a liquid crystal shutter 1 (a cyanobiphenyl liquid crystal manufactured by Merck Japan, trade name "E31L") is used by using a rectangular wave having an applied voltage of 100 V (effective value).
V ”), the scattering rate ρ (light transmittance in a scattering state without applying a voltage. Liquid crystal shutter 1)
Assuming that the received light intensity when there is no air and only air is I 0 and the received light intensity when the liquid crystal shutter 1 is placed and no voltage is applied is I 2 , it is expressed as ρ = (I 2 / I 0 ) × 100%. Was measured, and a value of ρ = 10% was obtained. The response time (rise and fall time) of the liquid crystal is 1 ms,
The light transmittance when the liquid crystal shutter is in a transmission state (expressed as (I 1 / I 0 ) × 100%, where I 1 is the received light intensity when the liquid crystal shutter 1 is placed and a voltage of 50 V is applied) is 75%.
【００１３】液晶の応答時間は、液晶シャッターをごく
短時間駆動したときに、液晶シャッターが開いている時
間（以下「τ」で表す）に等しいと考えられる。したが
って、τ＝１ｍ秒である。ＣＣＤカメラのフレーム１周
期Ｔ（１枚のフレーム画像を得るための露光時間）は６
６ｍ秒である。スミア低減比率Ｓｒは、ＣＣＤフレーム
１周期Ｔにおいて、ＣＣＤカメラに入ったであろう光強
度時間積分値に対する、液晶シャッターを散乱状態から
時間τだけ透過状態にし、その後散乱状態に戻した場合
のＣＣＤカメラに入った光強度時間積分値の比で表され
る。数式を使うと、 Ｓｒ＝τ／100 Ｔ＋( Ｔ−τ）ρ／100 Ｔ となる。したがって、スミア低減の点で透過散乱型液晶
の特性は、高散乱率、高速応答性が望ましい。また、高
画質情報の点では高光透過率が望ましい。The response time of the liquid crystal is considered to be equal to the time during which the liquid crystal shutter is open when the liquid crystal shutter is driven for a very short time (hereinafter represented by "τ"). Therefore, τ = 1 ms. One cycle T of the frame of the CCD camera (exposure time for obtaining one frame image) is 6
6 ms. The smear reduction ratio Sr is the CCD in the case where the liquid crystal shutter is changed from the scattering state to the transmission state for a time τ with respect to the integrated light intensity time that would have entered the CCD camera in one cycle T of the CCD frame, and then returned to the scattering state. It is expressed as the ratio of the light intensity time integration value that enters the camera. Using the equation, Sr = τ / 100T + (T−τ) ρ / 100T. Therefore, in terms of the reduction of smear, the characteristics of the transmission scattering type liquid crystal are desirably a high scattering rate and a high-speed response. A high light transmittance is desirable in terms of high image quality information.
【００１４】ここで、前述したように、ρ ＝１０％，
Ｔ＝６６ｍ秒，τ＝１ｍ秒という値を代入すると、Ｓｒ
＝０．１１４となる。この結果から、液晶シャッターを
使ったことにより、スミアを約１１％まで低減すること
ができたことが分かる。Here, as described above, ρ = 10%,
Substituting the values of T = 66 ms and τ = 1 ms gives Sr
= 0.114. From this result, it can be seen that the smear was reduced to about 11% by using the liquid crystal shutter.
【００１５】[0015]
【発明の効果】以上のように本発明のＣＣＤカメラを用
いた撮像装置によれば、透過散乱型液晶を用いてシャッ
ターを構成するので、光透過率が高く、波長帯域幅が広
いという透過散乱型液晶の特徴を生かした、優れた撮像
装置を実現することができる。また、前記ＣＣＤカメラ
と液晶シャッターとを、シュリーレン光学系に配置すれ
ば、シュリーレン光学系における絞りの開口を調節する
ことによって、電圧無印加時の散乱状態の散乱率をより
高くすることができる。As described above, according to the image pickup apparatus using the CCD camera of the present invention, since the shutter is constituted by using the transmission scattering type liquid crystal, the transmission scattering having a high light transmittance and a wide wavelength bandwidth is achieved. It is possible to realize an excellent imaging device utilizing the characteristics of the liquid crystal display. Further, if the CCD camera and the liquid crystal shutter are arranged in the schlieren optical system, the scatter ratio in the scattered state when no voltage is applied can be further increased by adjusting the aperture of the stop in the schlieren optical system.
【図１】シュリーレン光学系に配置された本発明の撮像
装置を示す図である。FIG. 1 is a diagram showing an imaging apparatus of the present invention arranged in a schlieren optical system.
【図２】液晶シャッターの透過／散乱状態と、カメラの
受光状態との関係を図示するグラフである。FIG. 2 is a graph illustrating a relationship between a transmission / scattering state of a liquid crystal shutter and a light receiving state of a camera.
１ 液晶シャッター ２ ＣＣＤカメラ ３ レンズ ４ 絞り 1 LCD shutter 2 CCD camera 3 Lens 4 Aperture
Claims (2)
メラを用いた撮像装置において、ＣＣＤカメラに入射す
る光をオンオフするシャッターとして、ＣＣＤイメージ
センサの電子シャッターと同期して作動する透過散乱型
の液晶シャッターを用いたことを特徴とするＣＣＤカメ
ラを用いた撮像。In a photographing apparatus using a CCD camera having a built-in CCD image sensor, a transmission / scattering type liquid crystal shutter which operates in synchronization with an electronic shutter of the CCD image sensor as a shutter for turning on / off light incident on the CCD camera. Imaging using a CCD camera, characterized in that a camera is used.
シュリーレン光学系に配置していることを特徴とする請
求項１記載のＣＣＤカメラを用いた撮像。2. The liquid crystal shutter according to claim 2, wherein
2. An image pick-up using a CCD camera according to claim 1, wherein the pick-up is arranged in a Schlieren optical system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9276160A JPH11112849A (en) | 1997-10-08 | 1997-10-08 | Imaging device using CCD camera |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9276160A JPH11112849A (en) | 1997-10-08 | 1997-10-08 | Imaging device using CCD camera |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11112849A true JPH11112849A (en) | 1999-04-23 |
Family
ID=17565582
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9276160A Pending JPH11112849A (en) | 1997-10-08 | 1997-10-08 | Imaging device using CCD camera |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11112849A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001061103A (en) * | 1999-08-23 | 2001-03-06 | Olympus Optical Co Ltd | Imaging device |
| WO2004055578A1 (en) * | 2002-12-16 | 2004-07-01 | Sony Corporation | Dimming device and driving method therefor, and imaging device |
| WO2006114259A1 (en) * | 2005-04-28 | 2006-11-02 | Jenoptik Laser, Optik, Systeme Gmbh | Device and method for reducing a smear effect by using a liquid crystal screen in a digital camera |
| KR100645635B1 (en) | 2004-11-30 | 2006-11-15 | 삼성전기주식회사 | Image pickup module with optical element |
-
1997
- 1997-10-08 JP JP9276160A patent/JPH11112849A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001061103A (en) * | 1999-08-23 | 2001-03-06 | Olympus Optical Co Ltd | Imaging device |
| WO2004055578A1 (en) * | 2002-12-16 | 2004-07-01 | Sony Corporation | Dimming device and driving method therefor, and imaging device |
| US7486349B2 (en) | 2002-12-16 | 2009-02-03 | Sony Corporation | Polymer network liquid crystal element with predetermined gap for dimming device having image processing, temperature detecting and pulse width control units therefor |
| KR100645635B1 (en) | 2004-11-30 | 2006-11-15 | 삼성전기주식회사 | Image pickup module with optical element |
| WO2006114259A1 (en) * | 2005-04-28 | 2006-11-02 | Jenoptik Laser, Optik, Systeme Gmbh | Device and method for reducing a smear effect by using a liquid crystal screen in a digital camera |
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