JPH0247020B2 - TEEPUSHISHUTANKENSHUTSUHOHO - Google Patents

TEEPUSHISHUTANKENSHUTSUHOHO

Info

Publication number
JPH0247020B2
JPH0247020B2 JP57229460A JP22946082A JPH0247020B2 JP H0247020 B2 JPH0247020 B2 JP H0247020B2 JP 57229460 A JP57229460 A JP 57229460A JP 22946082 A JP22946082 A JP 22946082A JP H0247020 B2 JPH0247020 B2 JP H0247020B2
Authority
JP
Japan
Prior art keywords
tape
light emitting
light
emitting diode
phototransistor
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
Application number
JP57229460A
Other languages
Japanese (ja)
Other versions
JPS59121640A (en
Inventor
Yasuhiro Yoneda
Mitsunobu Furumoto
Yoshiro Tsuchama
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to JP57229460A priority Critical patent/JPH0247020B2/en
Publication of JPS59121640A publication Critical patent/JPS59121640A/en
Publication of JPH0247020B2 publication Critical patent/JPH0247020B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
    • G11B15/02—Control of operating function, e.g. switching from recording to reproducing
    • G11B15/05—Control of operating function, e.g. switching from recording to reproducing by sensing features present on or derived from record carrier or container
    • G11B15/06—Control of operating function, e.g. switching from recording to reproducing by sensing features present on or derived from record carrier or container by sensing auxiliary features on record carriers or containers, e.g. to stop machine near the end of a tape
    • G11B15/08—Control of operating function, e.g. switching from recording to reproducing by sensing features present on or derived from record carrier or container by sensing auxiliary features on record carriers or containers, e.g. to stop machine near the end of a tape by photoelectric sensing

Description

【発明の詳細な説明】 産業上の利用分野 本発明は、テープ始終端部に設けられた透明テ
ープと磁気テープとの光透過量の差異を利用した
磁気記録再生装置のテープ始終端検出方法に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for detecting the beginning and end of a tape in a magnetic recording/reproducing apparatus using the difference in the amount of light transmitted between a transparent tape and a magnetic tape provided at the beginning and end of the tape. It is something.

従来例の構成とその問題点 第１図に従来のテープ始終端検出の構成を示
す。第１図において、LED1は発光ダイオード、
R1は抵抗器、１はテープ、PQ1は発光ダイオード
LED1から発せられた光をテープ１を通過して受
光できるように設置されたフオトトランジスタ、
R2はフオトトランジスタPQ1のエミツタ端子とア
ースとの間に接続された抵抗器、２は電圧比較
器、３は電圧比較器２の出力信号を入力する装置
のシーケンシヤル制御回路、４は基準電位Vaを
電圧比較器２に与えるための電源である。すなわ
ち、シーケンシヤル制御回路３は、テープ１が走
行中に、電圧比較器２より、透明テープである時
の信号が送られれば、テープ１の走行を停止する
ような動作をする。第２図は基本的なフオトトラ
ンジスタの特性の説明図で、フオトトランジスタ
が受光する照度Ｌと、フオトトランジスタのコレ
クタ−エミツタ間に流れる電流ICEとの関係を示
したものである。Conventional configuration and its problems FIG. 1 shows a conventional configuration for detecting the beginning and end of a tape. In Figure 1, LED 1 is a light emitting diode,
R 1 is resistor, 1 is tape, PQ 1 is light emitting diode
A phototransistor installed so that the light emitted from the LED 1 can pass through the tape 1 and receive it;
R 2 is a resistor connected between the emitter terminal of phototransistor PQ 1 and ground, 2 is a voltage comparator, 3 is a sequential control circuit of a device that inputs the output signal of voltage comparator 2, and 4 is a reference potential. This is a power supply for supplying Va to the voltage comparator 2. That is, the sequential control circuit 3 operates to stop the tape 1 from running if the voltage comparator 2 sends a signal indicating that the tape is a transparent tape while the tape 1 is running. FIG. 2 is an explanatory diagram of the basic characteristics of a phototransistor, showing the relationship between the illuminance L received by the phototransistor and the current ICE flowing between the collector and emitter of the phototransistor.

従来のテープ始終端部検出方法を説明する。発
光ダイオードLED1によつて発せられた光がテー
プ１を透過してフオトトランジスタPQ1へ到達す
る。仮にテープ１が透明テープであれば、フオト
トランジスタPQ1には電流ICEが流れ、フオトトラ
ンジスタPQ1エミツタの電位Vpが高くなる。そ
してこの電位Vpが基準電位Vaよりも高くなり、
電圧比較器２から制御回路３へ信号が発せられ、
テープ走行が停止する。もし仮にテープ１が磁気
テープであれば、発光ダイオードLED1から発せ
られた光がフオトトランジスタPQ1ではほとんど
受光できず、電位Vpは基準電位Vaを越えること
ができないように設計されている。すなわち、透
明テープと磁気テープとの光透過率の差を利用し
て、透明テープと磁気テープとの判別していた。 A conventional method for detecting the beginning and end of a tape will be explained. The light emitted by the light emitting diode LED 1 passes through the tape 1 and reaches the phototransistor PQ 1 . If the tape 1 is a transparent tape, a current ICE flows through the phototransistor PQ1 , and the potential Vp of the emitter of the phototransistor PQ1 increases. Then, this potential V p becomes higher than the reference potential V a ,
A signal is issued from the voltage comparator 2 to the control circuit 3,
Tape running stops. If the tape 1 were a magnetic tape, the phototransistor PQ 1 would hardly be able to receive the light emitted from the light emitting diode LED 1 , and the design is such that the potential V p cannot exceed the reference potential V a . . That is, the difference in light transmittance between the transparent tape and the magnetic tape has been utilized to distinguish between the transparent tape and the magnetic tape.

第３図に第１図に示す始終端検出回路における
発光ダイオードLED1の電流IDとフオトトランジ
スタPQ1のエミツタの電位Vpとの関係の説明図
である。第３図において、実線イはフオトトラン
ジスタPQ1へ発光ダイオードLED1から発せられ
る光以外の外乱光が全く影響を与えない条件下で
の透明テープにおけるIDとVpとの関係を示したも
ので、実線ロは外乱光の影響を最も受ける条件下
での磁気テープにおけるIDとVpとの関係を示した
ものである。基準電位Vaは実線イ，ロで示す特
性を考慮して決定される。即ち、VaをVa1の如く
大きく設定すると外乱光に対しては強くなるが、
発光ダイオードLED1に流す電流を大きくしない
と透明テープを検出することができなくなつてし
まう。逆に、VaをVa2の如く小さく設定すると、
磁気テープにおいても外乱光をフオトトランジス
タPQ1が受光して電位Vpが高くなつてしまい、
透明テープとの区別ができなくなつてしまう。第
３図のようにVaを設定すると、発光ダイオード
LED1には、最低I1以上の電流を流す必要が生じ
る。 FIG. 3 is an explanatory diagram of the relationship between the current ID of the light emitting diode LED 1 and the emitter potential V p of the phototransistor PQ 1 in the start/end detection circuit shown in FIG. 1. In Fig. 3, the solid line A shows the relationship between ID and Vp in the transparent tape under the condition that no disturbance light other than the light emitted from the light emitting diode LED 1 affects the phototransistor PQ 1 . The solid line (b) shows the relationship between ID and V p on the magnetic tape under conditions where it is most affected by disturbance light. The reference potential V a is determined by considering the characteristics shown by solid lines A and B. In other words, if V a is set to a large value such as V a1 , it will be strong against ambient light, but
Unless the current flowing through the light emitting diode LED 1 is increased, it will become impossible to detect the transparent tape. Conversely, if V a is set small like V a2 ,
Even in the case of magnetic tape, the phototransistor PQ 1 receives disturbance light and the potential V p becomes high.
It becomes impossible to distinguish it from transparent tape. When V a is set as shown in Figure 3, the light emitting diode
It becomes necessary to flow a current of at least I 1 or more through LED 1 .

第４図は、第３図と同様に、第１図に示す回路
におけるIDとVpとの関係を示す説明図で、実線
ハ，ニは、第３図に実線イで示す特性を、抵抗器
R2の抵抗値Rpを変えた時の特性を示している。
すなわち実線ハはRpの値が第３図に示す特性よ
り大きいとき、実線ニはRpの値が小さいときの
特性である。同様に、磁気テープの状態での外乱
光の影響のカーブも、Rpの値によつて第３図の
実線ロの傾斜は寝たり、立つたりする。すなわち
Rpの値によつて、フオトトランジスタPQ1の感度
が決まつてくる。 Similar to FIG. 3, FIG. 4 is an explanatory diagram showing the relationship between ID and V p in the circuit shown in FIG. 1, and solid lines C and D represent the characteristics shown by solid line A in FIG. Resistor
It shows the characteristics when the resistance value R p of R 2 is changed.
That is, the solid line C represents the characteristic when the value of R p is larger than the characteristic shown in FIG. 3, and the solid line D represents the characteristic when the value of R p is small. Similarly, in the curve of the influence of disturbance light on a magnetic tape, the slope of the solid line B in FIG. 3 becomes flat or steep depending on the value of R p . i.e.
The sensitivity of phototransistor PQ 1 is determined by the value of R p .

この様に、抵抗値Rpを第４図に実線ニで示す
特性の如く感度を下げたように設定すれば、外乱
光に対する影響は低減できるが、発光ダイオード
LED1に流す電流を大きくする必要が生じるし、
抵抗値Rpを第４図に実線ハで示す特性の如く感
度を上げたように設定すれば、外乱光に対して不
安定な検出回路となる。 In this way, if the resistance value R p is set to lower the sensitivity as shown by the solid line D in Figure 4, the influence of ambient light can be reduced, but the light emitting diode
It becomes necessary to increase the current flowing through LED 1 ,
If the resistance value R p is set so as to increase the sensitivity as shown by the solid line C in FIG. 4, the detection circuit becomes unstable with respect to ambient light.

すなわち、従来は夏の晴天時の直射光の下にお
いても誤動作しないように定数が決定されてい
た。この結果、フオトトランジスタPQ1の感度は
抵抗値Rpを小さくして感度を下げて、電流IDを大
きく流すことにより、安定性を確保していた。こ
のため、IDは数＋mAという大きい電流を流すこ
とになり、実際には電流低減の為に、間欠的に発
光ダイオードLED1に電流を流している。しかし
ながら、このような従来の方法では、室内等外乱
光の影響をあまり受けない時においても、同様に
大電流が流れているので、電力を無駄に消費して
いることになる。 That is, in the past, constants were determined so as not to malfunction even under direct light on a sunny day in summer. As a result, stability of the sensitivity of the phototransistor PQ 1 was ensured by lowering the resistance value R p to lower the sensitivity and allowing a large current ID to flow. Therefore, a large current of several +mA flows through ID , and in reality, current is intermittently passed through the light emitting diode LED 1 in order to reduce the current. However, in such a conventional method, a large current flows even when the device is not affected by ambient light, such as indoors, so power is wasted.

発明の目的 本発明は上記従来の欠点を解消するもので、消
費電力の低減化を図ることのできるテープ始終端
検出方法を得ることを目的とする。OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and an object of the present invention is to provide a tape start/end end detection method that can reduce power consumption.

発明の構成 上記目的を達するため、本発明のテープ始終端
検出方法は、テープ始終端部に設けられた透明テ
ープと磁気テープとの光透過率の差異を利用し、
発光素子とこの発光素子から発せられた光をテー
プを透過して受光するように設けられた受光素子
とでテープ始終端を検出するテープ始終端検出方
法であつて、外乱光レベルを検出してそのレベル
が小さいときには前記受光素子の感度を上げかつ
前記発光素子に流す電流を小さくするよう制御す
る構成である。Structure of the Invention In order to achieve the above object, the tape start/end detection method of the present invention utilizes the difference in light transmittance between a transparent tape and a magnetic tape provided at the tape start/end.
A tape start/end edge detection method that detects the tape start/end edge using a light emitting element and a light receiving element provided to transmit light emitted from the light emitting element through the tape, and detects the level of ambient light. When the level is low, the configuration is such that the sensitivity of the light receiving element is increased and the current flowing through the light emitting element is controlled to be decreased.

実施例の説明 以下、本発明の一実施例について、図面に基づ
いて説明する。DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

第５図はテープ始終端検出回路の回路ブロツク
図であり、第１図に示す構成要素と同一の構成要
素には同一の符号を付してその説明を省略する。
５は第２の電圧比較器、６は第２の電圧比較器５
に第２の基準電位VBを与えるための電源、７は
第１の電圧比較器２の出力ｅと第２の電圧比較器
５の出力６とを入力とするマイクロコンピユー
タ、８はマイクロコンピユータ７の出力端９から
の指令によつて発光ダイオードLED1を点燈させ
るための電流増幅器、Q1，Q2はマイクロコンピ
ユータ７の出力端１０からの指令によつて動作す
るトランジスタ、R3はトランジスタQ1のコレク
タと発光ダイオードLED1との間に接続された抵
抗器、R4はフオトトランジスタPQ1のエミツタと
トランジスタQ2のコレクタとの間に接続された
抵抗器、R5はトランジスタQ2とマイクロコンピ
ユータ７の出力端１１との間に接続された抵抗器
である。 FIG. 5 is a circuit block diagram of the tape start/end detection circuit, and the same components as those shown in FIG. 1 are given the same reference numerals and their explanations will be omitted.
5 is the second voltage comparator, 6 is the second voltage comparator 5
7 is a microcomputer whose inputs are the output e of the first voltage comparator 2 and the output 6 of the second voltage comparator 5; 8 is the microcomputer 7; Q 1 and Q 2 are transistors that operate according to commands from the output terminal 10 of the microcomputer 7, and R 3 is a transistor. A resistor connected between the collector of Q 1 and the light emitting diode LED 1 , R 4 a resistor connected between the emitter of phototransistor PQ 1 and the collector of transistor Q 2 , R 5 a resistor connected between the emitter of phototransistor PQ 1 and the collector of transistor Q 2 and the output terminal 11 of the microcomputer 7.

第６図はマイクロコンピユータ７が行なう始終
端検出を行なう処理手順のフローチヤートであ
る。 FIG. 6 is a flowchart of the processing procedure for detecting the start and end ends performed by the microcomputer 7.

第７図は発光ダイオードLED1に流れる電流ID
とフオトトランジスタPQ1のエミツタの電位Vp
との関係の説明図で、実線ホは外乱光の影響をほ
とんど受けないときでトランジスタQ2をオフし
たときの透明テープの場合、実線ヘは実線ホと同
状態のときの磁気テープの場合、実線トは外乱光
の影響を強く受けたときでトランジスタQ2をオ
ンしたときの透明テープの場合、実線チは実線ト
と同状態のときの磁気テープの場合を示してい
る。 Figure 7 shows the current I D flowing through the light emitting diode LED 1 .
and the potential V p of the emitter of phototransistor PQ 1
In the explanatory diagram of the relationship between The solid line G shows the case of the transparent tape when it is strongly influenced by disturbance light and the transistor Q2 is turned on, and the solid line H shows the case of the magnetic tape in the same state as the solid line G.

第８図は電位Vp及びVbとマイクロコンピユー
タ７の入出力のタイミングとの関係の説明図で、
ａはマイクロコンピユータ７の出力端９からの出
力波形で、この出力がハイレベルの期間だけ発光
ダイオードLED1を点灯する。ｂは第２の電圧比
較器５の出力信号を読込むタイミングを示してお
り、ハイレベルの期間に第２の電圧比較器５の出
力信号がマイクロコンピユータ７の入力端１２に
入力され、その入力信号は次の入力信号が読込ま
れるまでラツチされる。ｃは電位Vpと電位Vbと
の大小関係を示している。ｄはマイクロコンピユ
ータ７の端１０，１１からの出力波形であり、こ
の出力がハイレベルのときにトランジスタQ1，
Q2がオンする。ｅは第１の電圧比較器２の出力
信号を読込むタイミングを示しており、ハイレベ
ルの期間に第１の電圧比較器２の出力信号がマイ
クロコンピユータ７の入力端１３に読込まれる。
この読込みのタイミンは発光ダイオードLED1が
点灯するタイミングと同期されている。 FIG. 8 is an explanatory diagram of the relationship between the potentials V p and V b and the input/output timing of the microcomputer 7.
A is an output waveform from the output terminal 9 of the microcomputer 7, and the light emitting diode LED 1 is turned on only while this output is at a high level. b indicates the timing of reading the output signal of the second voltage comparator 5. During the high level period, the output signal of the second voltage comparator 5 is input to the input terminal 12 of the microcomputer 7, and the input signal is input to the microcomputer 7. The signal is latched until the next input signal is read. c indicates the magnitude relationship between the potential V p and the potential V b . d is the output waveform from the ends 10 and 11 of the microcomputer 7, and when this output is at high level, the transistors Q 1 ,
Q 2 turns on. e indicates the timing of reading the output signal of the first voltage comparator 2, and the output signal of the first voltage comparator 2 is read into the input terminal 13 of the microcomputer 7 during the high level period.
The timing of this reading is synchronized with the timing at which the light emitting diode LED 1 lights up.

テープ終始端検出には、まず外乱光レベルを検
出する。そのためマイクロコンピユータ７出力端
９からローレベルの信号を送り、電流増幅器８を
オフし、発光ダイオードLED1を消灯しておく。
また、マイクロコンピユータ７の出力端１１から
ローレベルの信号を送り、フオトトランジスタ
PQ1の感度を上げておく。このときに第８図ｂに
示したタイミングで第２の電圧比較器５の出力を
マイクロコンピユータ７が入力端１２より読込
む。もし電位Vpが電位Vbより低ければ、マイク
ロコンピユータ７の出力端１０，１１よりローレ
ベルの信号を送り、トランジスタQ1，Q2をオフ
させる。こうしてフオトトランジスタPQ1を高感
度にした状態で、発光ダイオードLED1に小電流
しか流れないようにして、第１の電圧比較器２の
出力を第８図ｅに示したように発光ダイオード
LED1が点灯している期間に同期したタイミング
でマイクロコンピユータ７の入力端１３より読込
む。外乱光の影響をあまり受けないときは、第７
図における実線ホ，ヘの特性を示すので、発光ダ
イオードLED1に流れる電流がI3（第７図）を越え
れば小電流でも磁気テープと透明テープとの区別
が可能である。逆にもし外乱光の影響が強く電位
Vpが電位Vbよりも高いときは、マイクロコンピ
ユータ７の出力端１０，１１からハイレベルの信
号を送り、トランジスタQ1，Q2をオンさせ、フ
オトトランジスタPQ1の感度を落とし、発光ダイ
オードLED1に流す電流を大きくして、第１の電
圧比較器２の出力を発光ダイオードLED1が点灯
している期間に同期したタイミングでマイクロコ
ンピユータ７の入力端１３より読込む。このよう
に、外乱光の影響が強いときは、第７図における
実線ト，チの特性を示すので発光ダイオード
LED1にはI4（第７図）以上の電流を流す様にする
ことが必要で、そうしないと磁気テープと透明テ
ープとの区別ができない。以上、第６図に示した
ように、外乱光の影響の強弱でフオトトランジス
タPQ1の感度、発光ダイオードLED1に流す電流
を変え、透明テープの検出を行う。第１の電圧比
較器２の出力を発光ダイオードLED1が点灯して
いる期間に同期してマイクロコンピユータ７が入
力するようにしておけば、発光ダイオードLED1
が消灯している期間は誤情報が入力されることな
く検出信頼性が高まる。 To detect the beginning and end of the tape, first the level of disturbance light is detected. Therefore, a low level signal is sent from the output terminal 9 of the microcomputer 7, the current amplifier 8 is turned off, and the light emitting diode LED 1 is turned off.
Also, a low level signal is sent from the output terminal 11 of the microcomputer 7, and the phototransistor
Increase the sensitivity of PQ 1 . At this time, the microcomputer 7 reads the output of the second voltage comparator 5 from the input terminal 12 at the timing shown in FIG. 8b. If the potential V p is lower than the potential V b , a low level signal is sent from the output terminals 10 and 11 of the microcomputer 7 to turn off the transistors Q 1 and Q 2 . In this way, with the phototransistor PQ 1 made highly sensitive, only a small current flows through the light emitting diode LED 1 , and the output of the first voltage comparator 2 is applied to the light emitting diode LED 1 as shown in Figure 8e.
It is read from the input terminal 13 of the microcomputer 7 at a timing synchronized with the period during which LED 1 is lit. When the influence of ambient light is not significant, use the 7th
As shown by the solid lines E and F in the figure, if the current flowing through the light emitting diode LED 1 exceeds I 3 (Figure 7), it is possible to distinguish between a magnetic tape and a transparent tape even with a small current. Conversely, if the influence of disturbance light is strong, the potential
When V p is higher than the potential V b , a high level signal is sent from the output terminals 10 and 11 of the microcomputer 7 to turn on the transistors Q 1 and Q 2 , reduce the sensitivity of the phototransistor PQ 1 , and turn on the light emitting diode. The current flowing through the LED 1 is increased, and the output of the first voltage comparator 2 is read from the input terminal 13 of the microcomputer 7 at a timing synchronized with the period in which the light emitting diode LED 1 is lit. In this way, when the influence of disturbance light is strong, the light emitting diode
It is necessary to make LED 1 flow a current greater than I 4 (Figure 7), otherwise it will not be possible to distinguish between magnetic tape and transparent tape. As described above, as shown in FIG. 6, the sensitivity of the phototransistor PQ 1 and the current flowing through the light emitting diode LED 1 are changed depending on the strength of the influence of ambient light to detect the transparent tape. If the output of the first voltage comparator 2 is input to the microcomputer 7 in synchronization with the period when the light emitting diode LED 1 is lit, the light emitting diode LED 1
During the period when the light is off, false information is not input and detection reliability increases.

マイクロコンピユータ７の入力端１３へハイレ
ベルの信号が第１の電圧比較器２より入力される
と、マイクロコンピユータ７から制御回路（図示
せず）へ指令が発せられ、テープ走行が停止され
る。入力端１３へローレベルの信号が入力される
ときは、ひき続いてテープ始終端検出が行なわれ
る。テープ１が透明テープであると、外乱光レベ
ルは磁気テープであるときのそれよりも大きい。
したがつて、テープ１が始終端検索開始より透明
テープであると、それほど強くない外乱光におい
ても電位Vpが電位Vbよりも高くなる可能性があ
り、この場合、発光ダイオードLED1に大電流を
流すことになつてしまうが、第６図の処理手順を
見てもわかるように、すぐに透明テープであるこ
とが検知されるので、発光ダイオードLED1の消
費電流の増大にはほとんど影響を与えない。 When a high level signal is input from the first voltage comparator 2 to the input terminal 13 of the microcomputer 7, a command is issued from the microcomputer 7 to a control circuit (not shown) to stop tape running. When a low level signal is input to the input terminal 13, detection of the beginning and end of the tape is subsequently performed. When the tape 1 is a transparent tape, the level of disturbance light is higher than when it is a magnetic tape.
Therefore, if the tape 1 is a transparent tape than the beginning and end search start, the potential V p may be higher than the potential V b even in the case of not-so-strong disturbance light, and in this case, the light emitting diode LED 1 will have a large impact. However, as you can see from the processing procedure in Figure 6, it is immediately detected that it is a transparent tape, so it has little effect on the increase in current consumption of the light emitting diode LED 1 . not give.

なお上記実施例においては、トランジスタQ1，
Q2を制御するのにマイクロコンピユータ７の２
つの出力端１０，１１を使用する例について説明
したが、この２つの出力のタイミングはまつたく
同一であるので、出力端１０，１１を１つの出力
端として共有しても良い。 Note that in the above embodiment, the transistors Q 1 ,
Microcomputer 7 2 is used to control Q 2.
Although an example in which two output terminals 10 and 11 are used has been described, since the timing of these two outputs is exactly the same, the output terminals 10 and 11 may be shared as one output terminal.

発明の効果 以上説明したように本発明によれば、外乱光の
影響が強いか否かを判断し、影響があまり強くな
いときは発光素子の消費電流を小さくするように
制御するので従来の如く偶発的に生じる外乱光の
影響度まで考慮して外乱光の影響度が小さいとき
でも大きいときと同様に発光素子に大電流を流す
場合と比較して、消費電力の低減化を図り得る。Effects of the Invention As explained above, according to the present invention, it is determined whether the influence of ambient light is strong or not, and when the influence is not so strong, the current consumption of the light emitting element is controlled to be small. Even when the influence of incidentally occurring disturbance light is considered, power consumption can be reduced compared to the case where a large current is passed through the light emitting element even when the influence of the disturbance light is small.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は従来方法に用いるテープ始終端検出回
路の回路ブロツク図、第２図はフオトトランジス
タの受光照度とそのコレクタ−エミツタ間に流れ
る電流との関係の説明図、第３図は従来方法にお
ける外乱光の影響がほとんどない条件下での透明
テープの場合及び外乱光の影響を強く受ける条件
下での磁気テープの場合のIDとVpとの関係の説明
図、第４図はフオトトランジスタの受光感度の大
小によつて変わるIDとVpとの関係の説明図、第５
図は本発明の一実施例に用いたテープ始終端検出
回路の回路ブロツク図、第６図は本発明の一実施
例におけるテープ始終端検出方法のフローチヤー
ト、第７図は外乱光の影響を強く受ける場合及び
そうでない場合のIDとVpとの関係の説明図、第８
図は外乱光レベルとマイクロコンピユータの入出
力のタイミングとの関係の説明図である。 １……テープ、２，５……電圧比較器、７……
マイクロコンピユータ、８……電流増幅器、
LED1……発光ダイオード、PQ1……フオトトラ
ンジスタ。 Fig. 1 is a circuit block diagram of the tape start/end detection circuit used in the conventional method, Fig. 2 is an explanatory diagram of the relationship between the received light intensity of the phototransistor and the current flowing between its collector and emitter, and Fig. 3 is the circuit diagram of the tape start/end detection circuit used in the conventional method. An explanatory diagram of the relationship between ID and V p in the case of transparent tape under conditions where there is almost no influence of disturbance light and in the case of magnetic tape under conditions where it is strongly affected by disturbance light. Figure 4 is for a phototransistor. Explanatory diagram of the relationship between I D and V p , which changes depending on the light receiving sensitivity of
The figure is a circuit block diagram of a tape start/end detection circuit used in an embodiment of the present invention, Figure 6 is a flowchart of a tape start/end detection method in an embodiment of the present invention, and Figure 7 is a circuit block diagram of a tape start/end detection circuit used in an embodiment of the present invention. Explanatory diagram of the relationship between I D and V p when it is strongly affected and when it is not, Part 8
The figure is an explanatory diagram of the relationship between the disturbance light level and the input/output timing of the microcomputer. 1... Tape, 2, 5... Voltage comparator, 7...
Microcomputer, 8...Current amplifier,
LED 1 ...Light emitting diode, PQ 1 ...Phototransistor.

Claims (1)

【特許請求の範囲】 １ テープ始終端部に設けられた透明テープと磁
気テープとの光透過率の差異を利用し、発光素子
とこの発光素子から発せられた光をテープを透過
して受光するように設けられた受光素子とでテー
プ始終端を検出するテープ始終端検出方法であつ
て、外乱光レベルを検出してそのレベルが小さい
ときには前記受光素子の感度を上げかつ前記発光
素子に流す電流を小さくするよう制御するテープ
始終端検出方法。 ２ 発光素子をオフした時に外乱光レベルを受光
素子で検出し、そのレベルが小さければ受光素子
の感度を上げて前記発光素子に流す電流を小さく
するように前記発光素子を間欠点灯させる特許請
求の範囲第１項記載のテープ始終端検出方法。[Claims] 1. Utilizing the difference in light transmittance between a transparent tape and a magnetic tape provided at the beginning and end of the tape, a light emitting element and light emitted from the light emitting element are transmitted through the tape and received. A tape start/end detection method detects the tape start/end using a light receiving element provided as shown in FIG. A method for detecting the beginning and end of a tape to reduce the 2. When the light emitting element is turned off, the level of disturbance light is detected by a light receiving element, and if the level is small, the sensitivity of the light receiving element is increased and the light emitting element is turned on intermittently so as to reduce the current flowing through the light emitting element. The method for detecting the beginning and end of a tape as described in scope 1.
JP57229460A 1982-12-28 1982-12-28 TEEPUSHISHUTANKENSHUTSUHOHO Expired - Lifetime JPH0247020B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP57229460A JPH0247020B2 (en) 1982-12-28 1982-12-28 TEEPUSHISHUTANKENSHUTSUHOHO

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP57229460A JPH0247020B2 (en) 1982-12-28 1982-12-28 TEEPUSHISHUTANKENSHUTSUHOHO

Publications (2)

Publication Number Publication Date
JPS59121640A JPS59121640A (en) 1984-07-13
JPH0247020B2 true JPH0247020B2 (en) 1990-10-18

Family

ID=16892544

Family Applications (1)

Application Number Title Priority Date Filing Date
JP57229460A Expired - Lifetime JPH0247020B2 (en) 1982-12-28 1982-12-28 TEEPUSHISHUTANKENSHUTSUHOHO

Country Status (1)

Country Link
JP (1) JPH0247020B2 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0119568B1 (en) * 1983-03-19 1989-02-08 GRUNDIG E.M.V. Elektro-Mechanische Versuchsanstalt Max Grundig holländ. Stiftung & Co. KG. Optoelectronic tape end switching
JPS6180541A (en) * 1984-09-26 1986-04-24 Sanyo Electric Co Ltd Detector of magnetic tape end
JP2825340B2 (en) * 1990-11-22 1998-11-18 キヤノン株式会社 Tape end detection device

Also Published As

Publication number Publication date
JPS59121640A (en) 1984-07-13

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