JPH067066B2 - Photo detection circuit - Google Patents
Photo detection circuitInfo
- Publication number
- JPH067066B2 JPH067066B2 JP1050260A JP5026089A JPH067066B2 JP H067066 B2 JPH067066 B2 JP H067066B2 JP 1050260 A JP1050260 A JP 1050260A JP 5026089 A JP5026089 A JP 5026089A JP H067066 B2 JPH067066 B2 JP H067066B2
- Authority
- JP
- Japan
- Prior art keywords
- output
- circuit
- transistor
- receiving element
- light
- 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
- 238000001514 detection method Methods 0.000 title claims description 5
- 230000003287 optical effect Effects 0.000 claims 1
- 230000010354 integration Effects 0.000 description 4
- 230000003321 amplification Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Landscapes
- Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Accessory Devices And Overall Control Thereof (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、プリンター等の出力装置を介して印字された
印字データを光検出により読み取る光検出回路に関する
ものである。Description: TECHNICAL FIELD The present invention relates to a photodetection circuit for reading print data printed by an output device such as a printer by photodetection.
本発明は、印字データを光検出により読み取る光検出回
路において光検出回路の出力を差動増幅回路で制御する
ことにより、外乱光の影響を少なくし、周囲の温度変化
や素子のバラツキに依存しない、安定した光検出をする
ようにしたものである。The present invention reduces the influence of ambient light by controlling the output of the photodetector circuit by the differential amplifier circuit in the photodetector circuit that reads print data by photodetection, and does not depend on ambient temperature changes and element variations. , Stable light detection is performed.
従来、印字データを光検出により読み取るための光検出
回路は第３図に示すように、フォトトランジスタからの
出力は外乱光による影響を考慮することなく、検出信号
を直接出力する回路が知られていた。Conventionally, as a photodetector circuit for reading print data by photodetection, as shown in FIG. 3, a circuit is known in which the output from the phototransistor directly outputs a detection signal without considering the influence of ambient light. It was
しかし、従来の光検出回路は、たとえば赤外線検出のフ
ォトセンサーであっても、屋外や屋内などの光の条件が
異なる場合には、外乱光による影響を受け、同じマーク
を読み取らせても、違うレベルの出力が発生する問題を
有していた。また、周囲の温度変化や素子のバラツキに
対する影響を受けやすかった。However, even if the conventional photodetector circuit is a photosensor for infrared detection, for example, when the conditions of light such as outdoors or indoors are different, it is affected by ambient light and even if the same mark is read, it is different. There was a problem that level output occurred. Also, it was easily affected by ambient temperature changes and element variations.
そこで、本発明の目的は、従来のこのような欠点を解決
するため、外乱光や周囲の温度や素子のバラツキに依存
せず、出力を安定させる事にある。Therefore, an object of the present invention is to stabilize the output without depending on the ambient light, the ambient temperature, and the variation of the element in order to solve such a conventional defect.
上記問題点を解決するために、本発明においては、光検
出回路の出力に積分回路、差動増幅回路、トランジスタ
を接続した構成とし、外乱光や周囲の温度素子のバラツ
キによる影響を無くすようにした。In order to solve the above problems, in the present invention, the output of the photodetector circuit is connected to an integrating circuit, a differential amplifier circuit, and a transistor so as to eliminate the influence of ambient light and variations in surrounding temperature elements. did.
上記の様な構成にすると、例えば外乱光があった場合、
光検出回路の出力に接続されている差動増幅回路により
フォトトランジスタの動作点を変えることができるので
ある。With the above configuration, for example, when there is ambient light,
The operating point of the phototransistor can be changed by the differential amplifier circuit connected to the output of the photodetector circuit.
以下に、この発明の実施例を図面に基づいて説明する。
第１図が光検出回路であり、第２図が該回路の各点にお
けるタイミングチャートである。第１図において、発光
ダイオードＤ１はドライバＱ１によりスイッチグされ光
変調されている。フォトトランジスタＰtrのエミッタ
は、トランジスタＱ２を介して接地され、トランジスタ
Ｑ２に流れる電流により、フォトトランジスタＰtrの動
作点を制御する構成となっている。該光変調信号は、抵
抗Ｒ2，コンデンサＣ１の時定数で積分され、該出力Ｂ
が差動増幅基板の差動入力の端子に接続されている。
一方、差動増幅器の端子は、ボリュームＶＲ１で設定
された電圧ｅ２が入力され、該差動増幅器の出力は、抵
抗Ｒ７を介し、トランジスタＱ２のベースに接続されて
いる。該差動増幅器は、抵抗Ｒ3，Ｒ4，Ｒ5，Ｒ6，オペ
アンプＯＰ１で構成されており、各々の定数は、Ｒ３＝
Ｒ４，Ｒ５＝Ｒ６に設定される。誤差動増幅器の入出力
特性は、オペアンプＯＰ１の増幅度が非常に高い条件で
は、下式(1)で決定され、積分回路出力ｅ１とボリュー
ムＶＲ１で設定されたｅ２の差を出力し、トランジスタ
Ｑ２のベース電流Ｉｂを制御する構成となっている。Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a photodetector circuit, and FIG. 2 is a timing chart at each point of the circuit. In FIG. 1, the light emitting diode D 1 is switched and optically modulated by the driver Q 1 . The emitter of the phototransistor Ptr is grounded through the transistor Q 2, the current flowing through the transistor Q 2, has a configuration for controlling the operating point of the phototransistor Ptr. The light modulation signal is integrated with the time constant of the resistor R 2 and the capacitor C 1, and the output B
Are connected to the differential input terminals of the differential amplifier substrate.
On the other hand, the voltage e 2 set by the volume VR 1 is input to the terminals of the differential amplifier, and the output of the differential amplifier is connected to the base of the transistor Q 2 via the resistor R 7 . Differential amplifier, resistors R 3, R 4, R 5 , R 6, is constituted by an operational amplifier OP 1, each of the constants, R 3 =
R 4 and R 5 = R 6 are set. The input / output characteristic of the error dynamic amplifier is determined by the following equation (1) under the condition that the amplification degree of the operational amplifier OP 1 is very high, and outputs the difference between the integration circuit output e 1 and e 2 set by the volume VR 1. However, the base current Ib of the transistor Q 2 is controlled.
該回路例において、例えば外乱光等により光電流が増加
すると、抵抗Ｒ２，コンデンサＣ１で構成される積分回
路出力ｅ１が上昇し、ボリュームＶＲ１で設定された電
圧ｅ２との差に応じて、差動増幅出力ｅ０が低下し、ト
ランジスタＱ２のベース電流Ｉｂを増加させ、Ｑ２の動
作点を変え、平均出力電圧ｅ１を下げる動作を行う。こ
れにより積分回路出力電圧ｅ１は、ボリュームＶＲ１で
決定された電圧ｅ２に漸近するよう制御される。このよ
うにして、第２図の従来出力Ａにおいては、外乱光の影
響を受けていたが、本発明の光検出回路において第２図
Ａ′に示すように外乱光の影響を受けないで通常の出力
を維持している。 In the circuit example, when the photocurrent increases due to, for example, ambient light, the integration circuit output e 1 formed by the resistor R 2 and the capacitor C 1 rises, and a difference from the voltage e 2 set by the volume VR 1 is generated. Accordingly, the differential amplification output e 0 is lowered, the base current Ib of the transistor Q 2 is increased, the operating point of Q 2 is changed, and the average output voltage e 1 is lowered. As a result, the integration circuit output voltage e 1 is controlled so as to gradually approach the voltage e 2 determined by the volume VR 1 . In this way, the conventional output A of FIG. 2 was affected by the ambient light, but the photodetector circuit of the present invention is not affected by the ambient light as shown in FIG. Maintain the output of.
本発明は、以上説明したように光検出付プリンターの光
検出回路の出力を積分回路、差動増幅回路、トランジス
タにより制御することで、外乱光による影響を少なく
し、周囲の温度変化や素子のバラツキ、暗電流などの変
化に依存しないで安定した光検出回路を構成できる。As described above, the present invention controls the output of the photodetector circuit of the printer with photodetector by the integration circuit, the differential amplifier circuit, and the transistor, thereby reducing the influence of ambient light, and changing the ambient temperature or the elements. A stable photodetector circuit can be configured without depending on variations such as variations and dark currents.
第１図は本発明に係る光検出回路図、第２図は従来の回
路と本発明にかかる光検出回路のタイムチャート、第３
図は従来の光検出回路図である。FIG. 1 is a photodetector circuit diagram according to the present invention, FIG. 2 is a time chart of a conventional circuit and the photodetector circuit according to the present invention, and FIG.
The figure is a conventional photodetector circuit diagram.
Claims (1)
される発光素子と、トランジスタを介して接地され、該
トランジスタに流れる電流により動作点が制御される受
光素子と、該受光素子からの光変調信号を積分する積分
回路と、該積分回路からの出力と予め設定された電圧と
の差を出力して前記トランジスタのベース電流を制御す
る差動増幅器とを有し、外乱光等により受光素子からの
検出出力が変化した時、前記差動増幅回路およびトラン
ジスタを介して前記受光素子の動作点を変化させ、外乱
光による影響を除去して受光素子の出力を所定の出力に
維持することを特徴とする光検出回路。1. A light emitting element which is switched by a driver to be optically modulated, a light receiving element which is grounded through a transistor and whose operating point is controlled by a current flowing through the transistor, and an optical modulation signal from the light receiving element. An integrating circuit for integrating and a differential amplifier for controlling a base current of the transistor by outputting a difference between an output from the integrating circuit and a preset voltage, and detecting from a light receiving element by ambient light or the like. When the output changes, the operating point of the light receiving element is changed via the differential amplifier circuit and the transistor, the influence of ambient light is removed, and the output of the light receiving element is maintained at a predetermined output. Light detection circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1050260A JPH067066B2 (en) | 1989-03-01 | 1989-03-01 | Photo detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1050260A JPH067066B2 (en) | 1989-03-01 | 1989-03-01 | Photo detection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02228526A JPH02228526A (en) | 1990-09-11 |
| JPH067066B2 true JPH067066B2 (en) | 1994-01-26 |
Family
ID=12854009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1050260A Expired - Lifetime JPH067066B2 (en) | 1989-03-01 | 1989-03-01 | Photo detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH067066B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111823736B (en) * | 2020-07-02 | 2025-03-18 | 西安富立叶微电子有限责任公司 | Label paper identification and positioning method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49121581A (en) * | 1973-03-22 | 1974-11-20 | ||
| JPS5510528A (en) * | 1978-07-08 | 1980-01-25 | Omron Tateisi Electronics Co | Photoelectric detector |
-
1989
- 1989-03-01 JP JP1050260A patent/JPH067066B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02228526A (en) | 1990-09-11 |
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