JPH0815321B2 - Photoelectric conversion device - Google Patents
Photoelectric conversion deviceInfo
- Publication number
- JPH0815321B2 JPH0815321B2 JP61300803A JP30080386A JPH0815321B2 JP H0815321 B2 JPH0815321 B2 JP H0815321B2 JP 61300803 A JP61300803 A JP 61300803A JP 30080386 A JP30080386 A JP 30080386A JP H0815321 B2 JPH0815321 B2 JP H0815321B2
- Authority
- JP
- Japan
- Prior art keywords
- photoelectric conversion
- signal
- drive
- dot
- conversion element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は光電変換素子を利用した光電変換装置に関す
るものである。The present invention relates to a photoelectric conversion device using a photoelectric conversion element.
従来、複数の光電変換素子を一列に配置したラインセ
ンサや、あるいは行列状に配置したエリアセンサを用い
た光電変換装置がある。Conventionally, there is a photoelectric conversion device using a line sensor in which a plurality of photoelectric conversion elements are arranged in a line, or an area sensor in which a plurality of photoelectric conversion elements are arranged in a matrix.
この様な光電変換装置では光電変換素子を駆動する駆
動素子の持つ駆動容量や光電変換素子の容量のバラツキ
が結果的に駆動パルスのリーク成分のバラツキとなっ
て、このバラツキ成分が本来情報信号として必要な光電
変換信号に重畳されて読出されてしまうという問題点が
あった。In such a photoelectric conversion device, variations in the drive capacity of the drive element that drives the photoelectric conversion element and variations in the capacity of the photoelectric conversion element result in variations in the leak component of the drive pulse, and this variation component is originally the information signal. There has been a problem that the necessary photoelectrically converted signal is read and superposed.
この駆動ノイズの発生について述べる。 The generation of this drive noise will be described.
第５−Ａ図は特開昭60−12764号に示される光電変換
素子の概略図、第５−Ｂ図は駆動パルス波形図、第５−
Ｃ図は光電変換素子のベース電位図である。FIG. 5-A is a schematic diagram of the photoelectric conversion element disclosed in JP-A-60-12764, FIG. 5-B is a drive pulse waveform diagram, and FIG.
FIG. 6C is a base potential diagram of the photoelectric conversion element.
第５−Ａ図において、Trはベース蓄積型トランジスタ
（以後Ｂ−Trと略す）、Coxは駆動パルスφＲによりＢ
−Trを逆バイアスあるいは正バイアスにする駆動用容量
である。Ｃ−Trはリフレツシユ用トランジスタである。
またCbcとCbeはＢ−Trのジヤンクシヨン容量で上述各容
量Cox,Cbc,Cbeを加算したものが電荷蓄積容量Ctotとな
る。In FIG. 5-A, Tr is a base storage type transistor (hereinafter abbreviated as B-Tr), Cox is B due to a driving pulse φ R.
-Tr is a drive capacitor that reverse biases or positive biases. C-Tr is a refresh transistor.
Further, Cbc and Cbe are junction capacitances of B-Tr, and the sum of the above-mentioned capacitances Cox, Cbc, and Cbe becomes the charge storage capacitance Ctot.
次に概略動作を述べる。 Next, the general operation will be described.
まずベース電位VBは初期電位がV0とする。時刻T1にお
いて、駆動パルスφＲがVOR電位になるとベースには駆
動容量Coxを通じてVaなる電圧が印加される。ここでVa
は次式で表わされる。First, the base potential V B has an initial potential V 0 . At time T 1 , when the drive pulse φ R becomes the V OR potential, the voltage Va is applied to the base through the drive capacitor Cox. Where Va
Is expressed by the following equation.
次に時刻T2において駆動パルスφUCがハイ電位になる
とＣ−Trは導通状態になる。従ってＢ−Trは順方向バイ
アスされた事により、ベース電位VBは急激に低下する。
この時刻T2からT3の期間TCがいわゆるリフレツシユ期間
である。 Next, at time T 2 , the drive pulse φ UC becomes high potential, and the C-Tr becomes conductive. Therefore, the B-Tr is forward-biased, so that the base potential V B rapidly decreases.
This period T C from time T 2 to T 3 is the so-called refresh period.
次に時刻T3においてベース電位VBはφＲがゼロ電位に
なるので、結局−Vaの電圧が印加された事になりV2の電
位におちつく。この逆バイアスされた状態が蓄積動作中
となる。Then the base potential V B is phi R is at time T 3 becomes zero potential, eventually settle down to the the result V 2 potential that voltage is applied -Va. This reverse-biased state is the accumulation operation.
ところで上述の動作説明は一つの光電変換素子につい
て述べたが、ラインセンサーあるいはエリアセンサーで
は多数の光電変換素子で構成されている。これら多数の
光電変換素子間では、Cox,Cbc,Cbeの容量値はコンマ数
％程度バラついてる。例えばCox＝Cbc＝Cbe0.014PF、
ＶφＲ＝5V,容量バラツキ0.2％とすると、容量分割電圧
VaのバラツキΔVaは約3mVとなる。By the way, the above description of the operation has described one photoelectric conversion element, but a line sensor or an area sensor is composed of a large number of photoelectric conversion elements. The capacitance values of Cox, Cbc, and Cbe vary among the many photoelectric conversion elements by a comma percentage. For example Cox = Cbc = Cbe0.014 PF ,
If Vφ R = 5V and capacitance variation is 0.2%, the capacitance division voltage is
The variation ΔVa of Va is about 3 mV.
このΔVaはリフレツシユ動作により軽減されてしまう
が、リフレツシユ動作モードから蓄積動作モード変移時
（時刻T3）、再びバラついてΔVbとなる。このバラツキ
ΔVbはΔVb＝−ΔVaではなく、実験結果から相関性は小
さい事が分った。その原因はCbc,Cbeがバイアス電圧依
存性が異なる事によるものと思われる。This ΔVa is reduced by the refresh operation, but when the refresh operation mode changes to the accumulation operation mode (time T 3 ), it again varies and becomes ΔVb. This variation ΔVb is not ΔVb = −ΔVa, and the experimental results show that the correlation is small. The cause seems to be that Cbc and Cbe have different bias voltage dependences.
従って次の読出しモードでＢ−Trを順方向にバイアス
したとき、ベース電位のバラツキは近似的に ΔV2ΔVa2＋ΔVb2＋2KΔVaΔｂ ……（２） （２）式で表わされＫは−１より大きい。Therefore, when the B-Tr is forward biased in the next read mode, the variation of the base potential is approximately ΔV 2 ΔVa 2 + ΔVb 2 + 2K ΔVaΔb (2) large.
その結果ΔＶは約４〜5mVの固定的な駆動ノイズとな
る。As a result, ΔV becomes a fixed drive noise of about 4 to 5 mV.
この様な駆動パルスのリーク成分のバラツキ（以後駆
動ノイズと呼ぶ）に対して、従来は上記駆動ノイズをメ
モリ手段に記憶させておき、後でセンサーからの読出し
信号からメモリ手段の駆動ノイズを減算する事により真
の情報信号を得ていた。With respect to such a variation in the leak component of the drive pulse (hereinafter referred to as drive noise), the drive noise is conventionally stored in the memory means, and the drive noise of the memory means is subtracted from the read signal from the sensor later. The true information signal was obtained by doing.
この様な駆動ノイズの補正方法は光電変換装置を大型
で高価格な魅力のないものとしてしまう。Such a method for correcting drive noise makes the photoelectric conversion device large and expensive and unattractive.
特にエリアセンサーになると、例えば水平と垂直素子
数がともに約500ケとすると全部で約25万素子となり、
さらに分解能を考慮すると数メガビツトのメモリが必要
となってしまう。Especially when it comes to area sensors, for example, if the number of horizontal and vertical elements is about 500, the total number is about 250,000.
Furthermore, considering the resolution, a memory of several megabits is required.
本発明は従来技術の欠点を除去するために光電変換素
子と、該光電変換素子を複数回読み出し駆動したときの
夫々の読出し信号を蓄積する複数の蓄積用キヤパシタ
と、該蓄積用キヤパシタの信号を点順次化する点順次手
段と、該点順次化手段の信号の一部をクランプするクラ
ンプ手段とを備えている。In order to eliminate the drawbacks of the prior art, the present invention provides a photoelectric conversion element, a plurality of storage capacitors that store respective read signals when the photoelectric conversion element is read and driven a plurality of times, and a signal of the storage capacitor. It is provided with a dot-sequential means for dot-sequentializing and a clamping means for clamping a part of the signal of the dot-sequentializing means.
本発明は駆動ノイズが光電変換素子のリフレツシユモ
ード，電荷蓄積モード，読出しモードによって発生する
各ノイズの加算によって発生し、同一動作モードであれ
ばその駆動ノイズはほとんど同じであると仮定し、まず
露光後読出した光電変換信号とその後同一動作モードで
読出した駆動ノイズとを点順次化し、そして駆動ノイズ
成分をクランプする事により結果的に光電変換信号成分
に含まれている駆動ノイズを除去するものである。According to the present invention, it is assumed that drive noise is generated by adding noises generated in the refresh mode, charge storage mode, and read mode of the photoelectric conversion element, and that the drive noises are almost the same in the same operation mode. A method that removes the drive noise contained in the photoelectric conversion signal component by dot-sequencing the photoelectric conversion signal read after exposure and the drive noise read in the same operation mode after that, and clamping the drive noise component. Is.
第１図は上述駆動ノイズを独立に読出す本発明の実施
例図である。この図はラインセンサー及びエリアセンサ
ーの一部を示している。FIG. 1 is a diagram showing an embodiment of the present invention in which the driving noise is read out independently. This figure shows a part of the line sensor and the area sensor.
蓄積容量CT1には光電変換信号を、CT2には駆動ノイズ
を一時的に蓄え水平信号線Ｓにそれぞれを点順次信号と
して読出す事が出来る。Tr1〜Tr6,S−Tr3はスイツチト
ランジスタ、Ｓ−Tr1,S−Tr2,STr4,STr5はトランジスタ
である。The photoelectric conversion signal can be temporarily stored in the storage capacitor CT 1 , and the driving noise can be temporarily stored in the CT 2 and can be read out to the horizontal signal line S as dot-sequential signals. Tr 1 to Tr 6 and S-Tr 3 are switch transistors, and S-Tr 1 , S-Tr 2 , STr 4 and STr 5 are transistors.
第２図においてタイミング図を示す。 A timing diagram is shown in FIG.
図示において、各駆動パルスはレベル“H"が各スイツ
チトランジスタを導通、レベル“L"が非導通状態を示す
ものとする。In the figure, it is assumed that each drive pulse has a level “H” that conducts each switch transistor and a level “L” that does not conduct.
TS期間はＢ−Trが逆バイアスされていて蓄積動作中で
ある。蓄積が終了すると、Tvc期間内に光電変換信号を
転送する前に垂直転送ラインＶと蓄積容量CT1上の不要
電荷を除去する。そしてTT1期間に光電変換信号を蓄積
容量CT1に転送する。T S period is during the accumulation operation B-Tr is being reverse biased. When the storage is completed, unnecessary charges on the vertical transfer line V and the storage capacitor C T1 are removed before the photoelectric conversion signal is transferred within the Tvc period. Then, in the T T1 period, the photoelectric conversion signal is transferred to the storage capacitor C T1 .
次に、再びTC1期間にリフレツシユ動作を行い、TT2期
間に駆動ノイズを蓄積容量CT2に転送する。その後Ｂ−T
rはTC2期間にリフレツシユ動作を行い次の蓄積を開始す
る。これで光電変換信号と駆動ノイズをそれぞれ独立に
得られた事になる。蓄積容量CT1とCT2に蓄積された信号
は駆動パルスφS1とφS2により同一の信号線Ｓ上に点順
次化されるべく転送される。それが図示TR1とTR2期間で
ある。駆動パルスφHCは信号線を基準電位にリセツトす
るためにある。上述の読出し動作により得られた信号が
図示Ｓの波形である。図においてμが駆動ノイズ、Ｓ′
が光電変換信号である。Next, the refresh operation is performed again in the T C1 period, and the drive noise is transferred to the storage capacitor C T2 in the T T2 period. Then BT
r performs the refresh operation during the T C2 period and starts the next accumulation. This means that the photoelectric conversion signal and the drive noise are obtained independently. The signals stored in the storage capacitors C T1 and C T2 are transferred on the same signal line S by the drive pulses φ S1 and φ S2 so as to be dot-sequential. These are the periods T R1 and T R2 shown. The drive pulse φ HC is for resetting the signal line to the reference potential. The signal obtained by the above read operation is the waveform S in the figure. In the figure, μ is drive noise and S '
Is a photoelectric conversion signal.
次に点順次信号Ｓは次段のクランプ回路CPCへ入力さ
れ、駆動パルスφS1により駆動ノイズＮの部分をクラン
プされる。その結果駆動ノイズは除去されて第２図示の
如く真の情報信号のみを得る事が出来る。Next, the dot-sequential signal S is input to the clamp circuit CPC in the next stage, and the portion of the drive noise N is clamped by the drive pulse φ S1 . As a result, drive noise is removed and only a true information signal can be obtained as shown in FIG.
クランプ回路CPCはトランジスタＳ−Tr1,S−Tr2から
構成されたバツフアアンプと結合容量し、およびクラン
パ用トランジスタＳ−Tr5,トランジスタＳ−Tr4,S−Tr5
から構成されたバツフアアンプ等で構成されている。The clamp circuit CPC couples with a buffer amplifier composed of transistors S-Tr 1 and S-Tr 2 , and a clamper transistor S-Tr 5 , transistors S-Tr 4 and S-Tr 5
It is composed of a buffer amplifier and the like.
次に第３図は第１図実施例の光電変換素子をエリアセ
ンサーに応用した模式図である。図示Ｖ−SRは垂直シフ
トレジスタ、Ｈ−SRは水平シフトレジスタ、Trmnはｍ行
ｎ列のベース蓄積型トランジスタである。該エリアセン
サーの動作は第１図実施例の光電変換素子と基本的に同
じであり、ただ異なるのは水平走査と垂直走査であるの
で詳細な説明を省略し、本発明の主旨である第３図実施
例の読出し信号のクランプについて説明する。Next, FIG. 3 is a schematic diagram in which the photoelectric conversion element of the embodiment of FIG. 1 is applied to an area sensor. In the figure, V-SR is a vertical shift register, H-SR is a horizontal shift register, and Trmn is a base storage transistor of m rows and n columns. The operation of the area sensor is basically the same as that of the photoelectric conversion element of the embodiment shown in FIG. 1, and the only difference is the horizontal scanning and the vertical scanning. Therefore, detailed description thereof will be omitted, and the third aspect of the present invention will be described. The clamp of the read signal in the illustrated embodiment will be described.
読出し信号の概略波形を第４図に示す。図示Ｓ′は読
出し信号線Ｓ上の信号で、φS1は駆動パルスである。図
においてＢ−Tr,Tr1の駆動ノイズと光電変換信号はそれ
ぞれN1,N2に対応する。同様に他のＢ−Trに対してもN2,
S2はTr12の出力、N3,S3はTr13、N4,S4はTr14…の出力に
対応している。上述の点順次信号は駆動パルスφS1によ
って駆動ノイズの部分をクランプされる。その結果駆動
ノイズは除去されて、真の情報信号のみが得られる。A schematic waveform of the read signal is shown in FIG. In the figure, S'is a signal on the read signal line S, and φ S1 is a drive pulse. B-Tr, the drive noise and the photoelectric conversion signal Tr 1 is corresponding to N1, N2 in FIG. Similarly, for other B-Tr, N2,
S2 corresponds to the output of Tr 12 , N3 and S3 correspond to the output of Tr 13 , N4 and S4 correspond to the output of Tr 14 ... The dot-sequential signal described above is clamped at the drive noise portion by the drive pulse φ S1 . As a result, drive noise is removed and only a true information signal is obtained.
〔その他の実施例〕 上述の実施例では１水平線信号読出し方式について述
べたが、本発明の主旨は１水平線信号の分割読み出し方
式あるいは多水平線信号同時読み出し方式にも適用でき
る。[Other Embodiments] In the above embodiments, the one-horizontal line signal reading method has been described, but the gist of the present invention can also be applied to the one-horizontal signal dividing reading method or the multi-horizontal signal simultaneous reading method.
また光電変換素子としてベース蓄積型トランジスタを
例にとり説明したが、MOS型やSIT型と呼ばれる撮像素子
にも適用できる。Further, although the base accumulation type transistor has been described as an example of the photoelectric conversion element, it can be applied to an image pickup element called a MOS type or a SIT type.
本発明は上述の様に駆動ノイズを光電変換信号と点順
次化したので、クランプ処理が可能となり、簡単な方法
で駆動ノイズを除去する事が出来る。According to the present invention, since the drive noise is dot-sequentially converted to the photoelectric conversion signal as described above, the clamp processing can be performed and the drive noise can be removed by a simple method.
第１図は本発明の第１の実施例図、 第２図は第１図実施例のタイミング図、 第３図は第１図実施例をエリアセンサーに応用した概略
図、 第４図はエリアセンサー信号波形の説明図、 第５−Ａ図〜第５−Ｃ図は光電変換素子の駆動説明図で
ある。 図において、 CT1,CT2は蓄積容量、 ＣとＳ−Tr3はクランパである。FIG. 1 is a first embodiment diagram of the present invention, FIG. 2 is a timing diagram of the FIG. 1 embodiment, FIG. 3 is a schematic diagram in which the FIG. 1 embodiment is applied to an area sensor, and FIG. FIGS. 5A to 5C are explanatory diagrams of sensor signal waveforms, and FIGS. 5A to 5C are driving explanatory diagrams of the photoelectric conversion element. In the figure, CT 1 and CT 2 are storage capacitors, and C and S-Tr 3 are clampers.
Claims (1)
み出し駆動したときの夫々の読出し信号を蓄積する複数
の蓄積用キヤパシタと、 該蓄積用キヤパシタの信号を点順次化する点順次化手段
と、 該点順次信号の一部をクランプするクランプ手段とを備
えた光電変換装置。1. A photoelectric conversion element, a plurality of storage capacitors that store respective read signals when the photoelectric conversion element is read out and driven a plurality of times, and dot-sequentializing means that dot-sequentially converts the signals of the storage capacitors. And a clamp means for clamping a part of the dot-sequential signal.
Priority Applications (14)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61300803A JPH0815321B2 (en) | 1986-12-16 | 1986-12-16 | Photoelectric conversion device |
| US07/096,534 US4914519A (en) | 1986-09-19 | 1987-09-14 | Apparatus for eliminating noise in a solid-state image pickup device |
| DE3752385T DE3752385T2 (en) | 1986-09-19 | 1987-09-16 | The solid state imaging device |
| EP01202926A EP1178673B1 (en) | 1986-09-19 | 1987-09-16 | Solid state image pickup apparatus |
| DE3752018T DE3752018T2 (en) | 1986-09-19 | 1987-09-16 | Solid state imaging device |
| EP87308199A EP0260954B1 (en) | 1986-09-19 | 1987-09-16 | Solid state image pickup apparatus |
| DE3752354T DE3752354T2 (en) | 1986-09-19 | 1987-09-16 | The solid state imaging device |
| EP96201979A EP0741493B1 (en) | 1986-09-19 | 1987-09-16 | Solid state image pickup apparatus |
| US07/547,996 US5331421A (en) | 1985-11-15 | 1990-06-13 | Solid state image pickup apparatus |
| US08/512,017 US5737016A (en) | 1985-11-15 | 1995-08-07 | Solid state image pickup apparatus for reducing noise |
| US08/705,002 US5771070A (en) | 1985-11-15 | 1996-08-29 | Solid state image pickup apparatus removing noise from the photoelectric converted signal |
| US09/040,275 US6747699B2 (en) | 1985-11-15 | 1998-03-18 | Solid state image pickup apparatus |
| US10/122,722 US20020167601A1 (en) | 1985-11-15 | 2002-04-16 | Solid state image pickup apparatus |
| US10/656,825 US20040046879A1 (en) | 1985-11-15 | 2003-09-08 | Solid state image pickup apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61300803A JPH0815321B2 (en) | 1986-12-16 | 1986-12-16 | Photoelectric conversion device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63152281A JPS63152281A (en) | 1988-06-24 |
| JPH0815321B2 true JPH0815321B2 (en) | 1996-02-14 |
Family
ID=17889286
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61300803A Expired - Lifetime JPH0815321B2 (en) | 1985-11-15 | 1986-12-16 | Photoelectric conversion device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0815321B2 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3781574A (en) * | 1972-10-20 | 1973-12-25 | Westinghouse Electric Corp | Coherent sampled readout circuit and signal processor for a charge coupled device array |
| JPS5544226A (en) * | 1978-09-25 | 1980-03-28 | Hitachi Ltd | Solidstate pick up unit |
| JPS5923675A (en) * | 1982-07-29 | 1984-02-07 | Nec Corp | Removing method of noise in mos type image sensor |
-
1986
- 1986-12-16 JP JP61300803A patent/JPH0815321B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3781574A (en) * | 1972-10-20 | 1973-12-25 | Westinghouse Electric Corp | Coherent sampled readout circuit and signal processor for a charge coupled device array |
| JPS5544226A (en) * | 1978-09-25 | 1980-03-28 | Hitachi Ltd | Solidstate pick up unit |
| JPS5923675A (en) * | 1982-07-29 | 1984-02-07 | Nec Corp | Removing method of noise in mos type image sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63152281A (en) | 1988-06-24 |
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