JPH03180079A - Light-emitting device - Google Patents
Light-emitting deviceInfo
- Publication number
- JPH03180079A JPH03180079A JP1319523A JP31952389A JPH03180079A JP H03180079 A JPH03180079 A JP H03180079A JP 1319523 A JP1319523 A JP 1319523A JP 31952389 A JP31952389 A JP 31952389A JP H03180079 A JPH03180079 A JP H03180079A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- current
- linearity
- characteristic
- conversion
- 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
- 238000006243 chemical reaction Methods 0.000 claims abstract description 39
- 230000003287 optical effect Effects 0.000 claims description 10
- 230000005540 biological transmission Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 1
Landscapes
- Led Devices (AREA)
- Optical Communication System (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明はＬＥＤ装置等の電気信号を光信号に変換する
発光装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light emitting device such as an LED device that converts an electrical signal into an optical signal.
第３図は従来のＬＥＤ装置を示す回路構成図である。同
図に示すように、入力電圧信号ｖＩＮが入力端子１を介
してＶ（電圧）−！（電流）変換アンプ２の人力に取込
まれている。Ｖ−１変換アンプ２は、入力端子信号ｖＩ
Ｎを所定のＶ−Ｉ変換特性で電流信号に変換しており、
この電流信号により可変電流源３を流れる電流信号ＩＩ
Ｎを決定している。この可変電流源３と電源Ｖ。Ｃとの
間に、アノード側を電源Ｖ。０に接続したＬＥＤ４を介
挿している。ＬＥＤ４は電流信号’ＩＮに応じて、所定
の発光効率で光信号を出力する。このように構成するこ
とにより、ＬＥＤ４は入力電圧信号ｖＩＮに応じた光強
度で発光することができる。FIG. 3 is a circuit diagram showing a conventional LED device. As shown in the figure, the input voltage signal vIN is applied via input terminal 1 to V (voltage) -! (Current) is taken into the human power of the conversion amplifier 2. The V-1 conversion amplifier 2 receives an input terminal signal vI
N is converted into a current signal with predetermined V-I conversion characteristics,
A current signal II flowing through the variable current source 3 due to this current signal
N is determined. This variable current source 3 and power supply V. C and power supply V on the anode side. An LED 4 connected to 0 is inserted. The LED 4 outputs a light signal with a predetermined luminous efficiency according to the current signal 'IN. With this configuration, the LED 4 can emit light with a light intensity that corresponds to the input voltage signal vIN.
上記した構成のＬＥＤ装置は、光通信用の送信器として
広く使用されている。送信器として用いる場合、伝送す
る信号が２値のディジタル信号の場合は、ＬＥＤ４の発
光状態は２つの状態が識別可能であればよい。したがっ
て、Ｖ−１変換アンプ２の入力端子信号ｖＩＮと電流信
号！ＩＮとのＶ−■変換特性は、第４図に示すように、
電圧Ｖ１の場合に電流１１．電圧ｖ２の場合に電流■２
という具合に２つの条件を満足すれば、Ｖ−■変換特性
は、必ずしも１１のように線形でなくてもよく、１２．
１３のように非線形であってもよい。一方、例えば動画
の転送のように、限られた時間内に大容量の情報を送り
たい場合、伝送する信号として情報量が多いアナログ信
号が適している。The LED device having the above configuration is widely used as a transmitter for optical communication. When used as a transmitter, if the signal to be transmitted is a binary digital signal, the light emitting state of the LED 4 only needs to be distinguishable between two states. Therefore, the input terminal signal vIN of the V-1 conversion amplifier 2 and the current signal! The V-■ conversion characteristics with IN are as shown in Figure 4.
When the voltage is V1, the current is 11. When voltage v2, current ■2
As long as the two conditions are satisfied, the V-■ conversion characteristic does not necessarily have to be linear as in 11, and 12.
It may be non-linear as shown in 13. On the other hand, when it is desired to send a large amount of information within a limited time, such as when transferring a moving image, an analog signal with a large amount of information is suitable as a signal to be transmitted.
伝送する信号がアナログ信号である場合、入力電圧信号
ｖＩＮの波形の再現性を保つ必要性から、Ｖ−１変換ア
ンプ２のＶ−１変換特性はアナログ伝送に利用される電
流区間１１〜Ｉ２において、第４図の９１に示す如く、
線形性が要求される。When the signal to be transmitted is an analog signal, it is necessary to maintain the reproducibility of the waveform of the input voltage signal vIN, so the V-1 conversion characteristics of the V-1 conversion amplifier 2 are set in the current section 11 to I2 used for analog transmission. , as shown at 91 in FIG.
Linearity is required.
しかしながら、Ｖ−１変換特性が線形性を保ったＶ−１
変換アンプ２を構成するには、回路が複雑化するという
問題点があった。しかも、アナログ信号の伝送に用いる
場合、周波数特性も１００ＭＨｚ程度の帯域を必要とす
るため、さらに回路が複雑化しコストがかかるという問
題点があった。However, the V-1 conversion characteristic maintains linearity.
There is a problem in configuring the conversion amplifier 2 that the circuit becomes complicated. Furthermore, when used for transmitting analog signals, the frequency characteristic requires a band of about 100 MHz, which poses a problem of further complicating the circuit and increasing cost.
また、仮にＶ−１変換アンプ２のＶ−１変換特性の線形
性を良くしても、ＬＥＤ４の発光効率特性の非線形性が
問題となる。第５図はＬＥＤ４の発光効率特性を示すグ
ラフである。同図に示すように、ＬＥＤの発光効率特性
Ｌ１は、大電流を流す程、その発光効率が上昇し、上向
きのカーブを怖く。このため、アナログ伝送に利用され
る電流区間１１〜■２において、十方向に約２％のリニ
アリティエラーＬＥＩが生じる。つまり、ＬＥＤ４等の
発光部の発光効率特性の非線形具合によっても、入力端
子信号ＶＩＮの波形の再現性が維持できず、アナログ伝
送に支障を与えてしまうという問題点があった。また、
発光効率特性が線形なＬＥＤ４を用いることも、コスト
がかかりすぎるという問題点があった。Moreover, even if the linearity of the V-1 conversion characteristic of the V-1 conversion amplifier 2 is improved, the nonlinearity of the luminous efficiency characteristic of the LED 4 poses a problem. FIG. 5 is a graph showing the luminous efficiency characteristics of the LED 4. As shown in the figure, the luminous efficiency characteristic L1 of the LED is such that the larger the current flows, the higher the luminous efficiency becomes, and the upward curve becomes scary. Therefore, a linearity error LEI of about 2% occurs in the ten directions in the current sections 11 to 2 used for analog transmission. In other words, there is a problem in that the reproducibility of the waveform of the input terminal signal VIN cannot be maintained due to the non-linearity of the luminous efficiency characteristics of the light emitting section such as the LED 4, which may impede analog transmission. Also,
The use of the LED 4 with linear luminous efficiency characteristics also had the problem of being too costly.
この発明は、上記のような問題点を解決するためになさ
れたもので、入力端子信号から光信号への変換特性の線
形性を高めた発光装置を簡単な回路構成で得ることを目
的とする。This invention was made to solve the above-mentioned problems, and aims to provide a light emitting device with improved linearity of conversion characteristics from an input terminal signal to an optical signal with a simple circuit configuration. .
この発明にかかる発光装置は、入力端子信号を電流信号
に変換する電圧・電流変換手段と、前記電流信号を光信
号に変換する発光手段とを備え、前記電圧・電流変換手
段の電圧電流変換特性は、前記電流信号の所定の電流範
囲において、前記発光効手段の発光効率特性のリニアリ
ティエラーと逆特性のリニアリティエラーを有している
。A light emitting device according to the present invention includes a voltage/current conversion means for converting an input terminal signal into a current signal, and a light emitting means for converting the current signal into an optical signal, and the voltage/current conversion characteristics of the voltage/current conversion means. has a linearity error that is opposite to the linearity error of the luminous efficiency characteristic of the luminous effect means in a predetermined current range of the current signal.
この発明における電圧・電流変換手段の電圧電流変換特
性は、電流信号の所定の電流範囲において、発光手段の
発光効率特性のリニアリティエラーと逆特性のリニアリ
ティエラーを有しているため、両者のリニアリティーエ
ラーは互いに打消し合い、その結果、入力端子信号に対
する光信号の変換率のリニアリティエラーは小さくなる
。The voltage-to-current conversion characteristic of the voltage/current conversion means in this invention has a linearity error of the luminous efficiency characteristic of the light emitting means and a linearity error of the opposite characteristic in a predetermined current range of the current signal, so the linearity error of both cancel each other out, and as a result, the linearity error of the conversion rate of the optical signal to the input terminal signal becomes small.
第１図はこの発明の一実施例であるＬＥＤ装置を示す回
路構成図である。同図に示すように、入力電圧信号ＶＩ
Ｎは前置アンプ９の人力に取込まれている。前置アンプ
９の利得Ａ、オフセット出力ＳＯは、外部に設けられた
利得・オフセット調整手段１５により、任意に設定可能
である。この前置アンプ９の入力電圧信号ｖＩＮを利得
Ａで増幅した増幅出力Ｓ１及びオフセット出力ＳＯがそ
れぞれ互いに差動対を形成するＮＰＮ ）ランジスタ１
０及び１１のベース人力となる。FIG. 1 is a circuit diagram showing an LED device as an embodiment of the present invention. As shown in the figure, the input voltage signal VI
N is taken into the human power of the preamplifier 9. The gain A and offset output SO of the preamplifier 9 can be arbitrarily set by an externally provided gain/offset adjustment means 15. An NPN transistor 1 in which the amplified output S1 obtained by amplifying the input voltage signal vIN of the preamplifier 9 with a gain A and the offset output SO each form a differential pair.
0 and 11 base manpower.
トランジスタ１０のコレクタと電源Ｖ２Ｃ間に、アノー
ドを電源Ｖ。。側に接続したＬＥＤ４が介押されており
、トランジスタ１０のエミッタは抵抗１２を介して定電
流源１４に接続されている。The anode is connected between the collector of the transistor 10 and the power supply V2C. . An LED 4 connected to the side is inserted, and the emitter of the transistor 10 is connected to a constant current source 14 via a resistor 12.
方、トランジスタ１１のコレクタは電源Ｖ。０に接続さ
れ、エミッタは抵抗１３を介して定電流源１４に接続さ
れている。定電流源１４は、外部に設けられた電流調整
手段１６により、トランジスタ１０．１１から成る差動
回路が飽和する電流Ｉ。On the other hand, the collector of transistor 11 is connected to power supply V. 0, and its emitter is connected to a constant current source 14 via a resistor 13. The constant current source 14 generates a current I, which saturates the differential circuit including the transistors 10 and 11, by means of an externally provided current adjusting means 16.
をイモ意に変更可能である。can be changed at will.
上記したトランジスタ１０．’１１より構成される差動
回路のＶ−１変換特性１４を第２図に示す。Transistor 10 described above. FIG. 2 shows the V-1 conversion characteristic 14 of the differential circuit constructed from the circuit shown in FIG.
なお、同図において、ΔｖＳは、入力端子信号Ｖ１Ｎが
その利用範囲Ｖｌ〜ｖ２間を変化した時の、トランジス
タ１０．１１から成る差動回路の入力端子ＶＳ （−３
ｌ−８ｏ）の変化範囲を示している。同図に示すように
、Ｖ−Ｉ変換特性ｆＩ４は人力電圧ＶＳが上昇するにつ
れ、傾きがゆるやかになるため、電流区間■１〜Ｉ２に
おいて、一方向にリニアリティーエラーＬＥ２を有する
。これは、入力端子ｖＳの上昇時に、定電流源１４によ
り決定°する電流量Ｉ。でトランジスタ１０．１１から
成る差動回路が飽和することに起因している。したがっ
て、トランジスタ１０．１１から成る差動回路は、電流
１ｏを上げると、リニアリティエラーＬＥ２が小さくな
り、電流Ｉｏを下げると、リニアリティエラーＬＥ２が
大きくなる。このように、Ｖ−Ｉ変換特性１１４は、ア
ナログ伝送に利用される電流区間１１〜■２において、
一方向にリニアリティエラーＬＥ２を有しており、第５
図で示したＬＥＤ４の発光効率特性Ｌ１のリニアリティ
ーエラーＬＥＩと逆特性のリニアリティエラーを有して
いることになる。In the figure, ΔvS is the input terminal VS (-3
1-8o) shows the range of change. As shown in the figure, the V-I conversion characteristic fI4 has a linearity error LE2 in one direction in the current section 1 to I2 because the slope becomes gentler as the human power voltage VS increases. This is the current amount I determined by the constant current source 14 when the input terminal vS rises. This is due to the fact that the differential circuit made up of transistors 10 and 11 becomes saturated. Therefore, in the differential circuit composed of transistors 10 and 11, when the current Io is increased, the linearity error LE2 becomes smaller, and when the current Io is reduced, the linearity error LE2 becomes larger. In this way, the V-I conversion characteristic 114 is such that in the current section 11 to ■2 used for analog transmission,
It has a linearity error LE2 in one direction, and the fifth
This means that it has a linearity error that is opposite to the linearity error LEI of the luminous efficiency characteristic L1 of the LED 4 shown in the figure.
このような構成において、電流調整手段１６により電流
区間■１〜Ｉ２におけるＶ−１変換特性１４のリニアリ
ティエラーＬＥ２が発光効率特性Ｌ１のリニアリティエ
ラーＬＥＩと同程度になるように、定電流源１４の電流
■。を調整すると、２つのりニアリティエラーＬＥＩ、
ＬＥ２が互いに打消し合う。その結果、電圧区間ｖ１〜
Ｖ２において、入力端子信号ｖＩＮ応答してＬＥＤ４よ
り出力される光信号の発光強度のリニアリティエラーが
ほとんどなくなるため、入力端子信号”ＩＮを再現性良
＜ＬＥＤ４の光信号に変換して出力することができる。In such a configuration, the constant current source 14 is adjusted by the current adjusting means 16 so that the linearity error LE2 of the V-1 conversion characteristic 14 in the current section 1 to I2 becomes approximately the same as the linearity error LEI of the luminous efficiency characteristic L1. Current ■. When adjusting, two linearity errors LEI,
LE2 cancel each other out. As a result, the voltage section v1~
In V2, there is almost no linearity error in the light emission intensity of the optical signal output from LED4 in response to the input terminal signal vIN, so it is possible to convert the input terminal signal "IN" into an optical signal of LED4 with good reproducibility and output it. can.
また、第１図に示すように、その回路構成は簡単で済む
。Furthermore, as shown in FIG. 1, the circuit configuration is simple.
ところで、入力電圧信号ＶＩＮの利用範囲Ｖ１〜Ｖ２は
通常固定されているが、ＬＥＤ４の利用電流範囲１１〜
■２は、ＬＥＤの種類、ユーザの要望等により変更する
場合がある。このような場合でも、利得・オフセット調
整手段１５により前置アンプ９の利得Ａ、オフセット出
力ＳＯを適当に変更し、トランジスタ１０．１１から成
る差動回路への入力端子ｖＳの変化範囲ΔｖＳを変える
ことにより、入力端子信号ｖＩＮの利用範囲ｖ１〜Ｖ２
は同じであっても、様々なＬＥＤ４の利用電流範囲に適
合した電圧・電流変換を行うことができ、その汎用性は
増す。By the way, the usable range V1 to V2 of the input voltage signal VIN is usually fixed, but the usable current range 11 to V2 of the LED 4 is
(2) may be changed depending on the type of LED, user's request, etc. Even in such a case, the gain A and offset output SO of the preamplifier 9 are appropriately changed by the gain/offset adjusting means 15, and the range of change ΔvS of the input terminal vS to the differential circuit consisting of the transistors 10 and 11 is changed. By this, the usage range v1 to V2 of the input terminal signal vIN
Even if they are the same, voltage/current conversion can be performed that is suitable for the current range used by various LEDs 4, increasing its versatility.
以上説明したように、この発明によれば、電圧・電流変
換手段の電圧電流変換特性は、電流信号の所定の電流範
囲において、発光手段の発光効率特性のリニアリティエ
ラーと逆特性のリニアリティエラーを有しているため、
両者のリニアリティーエラーは互いに打消し合い、その
結果、入力端子信号に対する光信号の変換率のリニアリ
ティエラーは小さくなる。したがって、人力信号に対す
る光信号の変換率のリニアリティエラーは改善され、線
形性は高まる。しかも、電圧・電流変換手段の電圧電流
変換特性及び発光手段の発光効率特性それぞれは正確に
線形性を有する必要がないため、簡単な回路構成で実現
できる効果がある。As explained above, according to the present invention, the voltage-to-current conversion characteristic of the voltage/current conversion means has a linearity error that is opposite to the linearity error of the luminous efficiency characteristic of the light emitting means in a predetermined current range of the current signal. Because of this,
Both linearity errors cancel each other out, and as a result, the linearity error in the conversion rate of the optical signal with respect to the input terminal signal becomes small. Therefore, the linearity error in the conversion rate of the optical signal to the human signal is improved and the linearity is increased. Moreover, since the voltage-current conversion characteristic of the voltage-current conversion means and the luminous efficiency characteristic of the light-emitting means do not need to have accurate linearity, the effect can be achieved with a simple circuit configuration.
第１図はこの発明の一実施例であるＬＥＤ装置を示す回
路構成図、第２図は第１図の差動回路の出力特性を示す
グラフ、第３図は従来のＬＥＤ装置を示す回路構成図、
第４図は従来のＶ−１変換アンプの変換特性を示すグラ
フ、第５図は従来のＬＥＤの発光効率特性を示すグラフ
である。
図において、４はＬＥＤ、９は前置アンプ、１０．１１
はＮＰＮ ）ランジスタ、１４は定電流源である。
なお、各図中同一符号は同一または相当部分を示す。FIG. 1 is a circuit configuration diagram showing an LED device that is an embodiment of the present invention, FIG. 2 is a graph showing the output characteristics of the differential circuit in FIG. 1, and FIG. 3 is a circuit configuration diagram showing a conventional LED device. figure,
FIG. 4 is a graph showing the conversion characteristics of a conventional V-1 conversion amplifier, and FIG. 5 is a graph showing the luminous efficiency characteristics of a conventional LED. In the figure, 4 is an LED, 9 is a preamplifier, 10.11
is an NPN) transistor, and 14 is a constant current source. Note that the same reference numerals in each figure indicate the same or corresponding parts.
Claims (1)
換手段と、 前記電流信号を光信号に変換する発光手段とを備え、 前記電圧・電流変換手段の電圧電流変換特性は、前記電
流信号の所定の電流範囲において、前記発光手段の発光
効率特性のリニアリティエラーと逆特性のリニアリティ
エラーを有することを特徴とする発光装置。(1) Voltage/current conversion means for converting an input voltage signal into a current signal; and light emitting means for converting the current signal into an optical signal; the voltage/current conversion characteristic of the voltage/current conversion means is such that the current signal A light emitting device having a linearity error having a characteristic opposite to a linearity error of the luminous efficiency characteristic of the light emitting means in a predetermined current range.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1319523A JPH03180079A (en) | 1989-12-08 | 1989-12-08 | Light-emitting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1319523A JPH03180079A (en) | 1989-12-08 | 1989-12-08 | Light-emitting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03180079A true JPH03180079A (en) | 1991-08-06 |
Family
ID=18111183
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1319523A Pending JPH03180079A (en) | 1989-12-08 | 1989-12-08 | Light-emitting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03180079A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002077958A1 (en) * | 2001-03-22 | 2002-10-03 | Canon Kabushiki Kaisha | Circuit for driving active-matrix light-emitting element |
-
1989
- 1989-12-08 JP JP1319523A patent/JPH03180079A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002077958A1 (en) * | 2001-03-22 | 2002-10-03 | Canon Kabushiki Kaisha | Circuit for driving active-matrix light-emitting element |
| JPWO2002077958A1 (en) * | 2001-03-22 | 2004-07-15 | キヤノン株式会社 | Driver circuit for active matrix light emitting device |
| US6992663B2 (en) | 2001-03-22 | 2006-01-31 | Canon Kabushiki Kaisha | Driving circuit of active matrix type light-emitting element |
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