JPH08139395A - Semiconductor laser and light quantity detection circuit - Google Patents
Semiconductor laser and light quantity detection circuitInfo
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- JPH08139395A JPH08139395A JP30262394A JP30262394A JPH08139395A JP H08139395 A JPH08139395 A JP H08139395A JP 30262394 A JP30262394 A JP 30262394A JP 30262394 A JP30262394 A JP 30262394A JP H08139395 A JPH08139395 A JP H08139395A
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- Prior art keywords
- laser
- temperature
- light
- semiconductor laser
- photodiode
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は半導体レーザと、半導体
レーザの光量を検出してレーザの光量を制御する光量検
出回路に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser and a light amount detecting circuit for detecting the light amount of the semiconductor laser and controlling the light amount of the laser.
【０００２】[0002]
【従来の技術】従来の半導体レーザ１０１は図６示すよ
うに、基板１０２の上に、レーザチップ１０４とレーザ
チップ１０４の照射レーザ光の一部（Ａ１０２）を受光
する受光素子１０３とを備え、キャップ１０６で覆った
ものである。１０５はレーザチップ１０４のヒートシン
クを兼ねたステム、１０７はレーザ光Ａ１０１を外部へ
透過させる透明板である。2. Description of the Related Art As shown in FIG. 6, a conventional semiconductor laser 101 comprises a substrate 102, a laser chip 104, and a light receiving element 103 for receiving a part (A102) of laser light emitted from the laser chip 104. It is covered with a cap 106. Reference numeral 105 is a stem that also serves as a heat sink of the laser chip 104, and 107 is a transparent plate that transmits the laser light A101 to the outside.
【０００３】このような従来の半導体レーザは、レーザ
光量の制御のためにレーザ光の一部を受光素子１０３で
受光してレーザチップ１０４の発光量を検出し、その検
出値に基づいてレーザ光量の制御を行っているものであ
る。In such a conventional semiconductor laser, in order to control the laser light amount, a part of the laser light is received by the light receiving element 103, the light emission amount of the laser chip 104 is detected, and the laser light amount is based on the detected value. Is being controlled.
【０００４】そして、この半導体レーザ１０１にはレー
ザチップ１０４の発光量を検出用する受光素子の温度を
検出する検出手段は設けられてなく、また、光量検出回
路にも受光素子の温度に応じて検出値に補正を加えるよ
うなことは行われていなかった。The semiconductor laser 101 is not provided with detecting means for detecting the temperature of the light receiving element for detecting the amount of light emitted from the laser chip 104, and the light amount detecting circuit also depends on the temperature of the light receiving element. No correction was made to the detected value.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら上記従来
例では、受光素子の温度特性による検出値の補正を行っ
ていなかったために、半導体レーザの自己発熱や周囲温
度の影響によりレーザ光量の検出値が変動してしまい、
レーザ光量の制御を精度良く行うことができなかった。However, in the above-mentioned conventional example, since the detection value is not corrected by the temperature characteristic of the light receiving element, the detection value of the laser light amount fluctuates due to the self-heating of the semiconductor laser and the influence of the ambient temperature. And then
The amount of laser light could not be controlled accurately.
【０００６】本発明は上記従来技術の問題を解決するた
めになされたもので、その目的とするところは、半導体
レーザの自己発熱や周囲温度の影響にかかわらず、受光
素子が正確にレーザ光量の検出を行えるように、温度検
出手段を設けて検出値の温度補正を行うことを目的とす
る。The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to make sure that the light receiving element accurately controls the laser light quantity regardless of the self-heating of the semiconductor laser and the influence of the ambient temperature. An object of the present invention is to provide a temperature detecting means to perform temperature correction of a detected value so that detection can be performed.
【０００７】[0007]
【課題を解決するための手段】上記の目的を達成するた
めに、本発明にあっては、レーザ発光素子とこのレーザ
発光素子から発光されたレーザ光の一部を受光する受光
素子とを備え、レーザ発光量を前記受光素子の光量検出
値を用いて制御する半導体レーザにおいて、前記受光素
子に温度を検出する温度検出手段を設けたことを特徴と
する。In order to achieve the above object, the present invention comprises a laser light emitting element and a light receiving element for receiving a part of laser light emitted from the laser light emitting element. In a semiconductor laser for controlling a laser emission amount using a light amount detection value of the light receiving element, a temperature detecting means for detecting a temperature is provided in the light receiving element.
【０００８】また、光量検出回路は、温度検出手段を設
けた受光素子の光量検出値に、この温度検出手段の検出
温度に応じて前記光量検出値に補正を加えることを特徴
とする。Further, the light quantity detection circuit is characterized in that the light quantity detection value of the light receiving element provided with the temperature detection means is corrected according to the temperature detected by the temperature detection means.
【０００９】さらに、レーザ発光素子とこのレーザ発光
素子から発光されたレーザ光の一部を受光する受光素子
とを備え、レーザ発光量を前記受光素子の受光量を用い
て制御する半導体レーザにおいて、前記受光素子の温度
を検出する温度検出手段を設け、この温度検出手段の検
出温度に応じて光量検出値に補正を加える光量検出回路
によりレーザ発光量を制御することを特徴とする。Further, in a semiconductor laser having a laser light emitting element and a light receiving element for receiving a part of the laser light emitted from the laser light emitting element, and controlling the laser light emission amount using the light receiving amount of the light receiving element, It is characterized in that temperature detecting means for detecting the temperature of the light receiving element is provided, and the laser light emission amount is controlled by a light amount detecting circuit for correcting the light amount detection value according to the temperature detected by the temperature detecting means.
【００１０】[0010]
【作用】上記のように構成された本発明においては、受
光素子に設けた温度検出手段が受光素子の温度を検出
し、この検出温度に応じて光量検出値に補正を加える。
また、光量検出回路は温度検出手段の検出温度に応じて
受光素子の光量検出値に補正を行う。In the present invention constructed as described above, the temperature detecting means provided in the light receiving element detects the temperature of the light receiving element, and the light amount detection value is corrected according to the detected temperature.
Further, the light amount detection circuit corrects the light amount detection value of the light receiving element according to the temperature detected by the temperature detecting means.
【００１１】[0011]
（第１実施例）以下に、本発明を図示の実施例に基づい
て説明する。図１は本実施例の半導体レーザ１の構成図
である。図１において４はレーザ発光素子としてのレー
ザチップ、５はレーザチップ４のヒートシンクを兼ねた
ステム、１１はレーザチップへの端子、３はレーザチッ
プ４のレーザ光量を検出するための受光素子としてのフ
ォトダイオード、１０はフォトダイオード３への端子、
２がフォトダイオード３の温度検出手段としてのフォト
ダイオード３の固定部材３ａに設けられたチップ型のサ
ーミスタ、８，９はサーミスタ２への端子、６はキャッ
プ、７は透明板、１２は各端子と端子間を接続するため
のボンディングワイヤである。(First Embodiment) The present invention will be described below based on the illustrated embodiment. FIG. 1 is a configuration diagram of a semiconductor laser 1 of this embodiment. In FIG. 1, 4 is a laser chip as a laser light emitting element, 5 is a stem that also serves as a heat sink of the laser chip 4, 11 is a terminal to the laser chip, and 3 is a light receiving element for detecting the laser light amount of the laser chip 4. The photodiode 10 is a terminal to the photodiode 3,
2 is a chip-type thermistor provided on the fixing member 3a of the photodiode 3 as a temperature detecting means for the photodiode 3, 8 and 9 are terminals to the thermistor 2, 6 is a cap, 7 is a transparent plate, and 12 is each terminal. And a bonding wire for connecting between the terminal and the terminal.
【００１２】図２は本半導体レーザ１の光量を検出する
ための光量検出回路を含めたレーザ光量制御回路１３で
ある。図中１４，１５は半導体レーザ１内部のチップ型
ＮＴＣサーミスタ２と共にレーザチップ４の光量に応じ
たフォトダイオード３からの電流を電圧に変換するため
のオペアンプと抵抗、１６はオペアンプ１４の出力電圧
をもとにレーザチップ４への駆動電流を制御するための
レーザドライブ回路である。FIG. 2 shows a laser light amount control circuit 13 including a light amount detection circuit for detecting the light amount of the semiconductor laser 1. In the figure, 14 and 15 are operational amplifiers and resistors for converting the current from the photodiode 3 according to the light quantity of the laser chip 4 into a voltage together with the chip type NTC thermistor 2 inside the semiconductor laser 1, and 16 is the output voltage of the operational amplifier 14. Originally, it is a laser drive circuit for controlling the drive current to the laser chip 4.
【００１３】図３，図４はフォトダイオード３の温度特
性を示した図である。3 and 4 are diagrams showing the temperature characteristics of the photodiode 3.
【００１４】図３に示すようにレーザ光量一定の場合に
おいて、フォトダイオード電流の単位温度変化率αは使
用温度範囲内（２５℃−Ｔ≦ｔ≦２５℃＋Ｔ）において
一定である。As shown in FIG. 3, when the laser light amount is constant, the unit temperature change rate α of the photodiode current is constant within the operating temperature range (25 ° C.−T ≦ t ≦ 25 ° C. + T).
【００１５】また、図４に示すようにこの変化率αがレ
ーザ光量にもよらず一定である場合、前記オペアンプ１
４の出力電圧（Ｖｏｕｔ）は以下の数式１，２及び３の
ように表わされる。Further, as shown in FIG. 4, when the change rate α is constant regardless of the laser light amount, the operational amplifier 1
The output voltage (Vout) of No. 4 is expressed by the following equations 1, 2 and 3.
【００１６】[0016]
【数１】 Ｖｏｕｔ＝Ｖｒ−（ｉｄ＋Δｉｄ）×（Ｒ＋ｒ＋Δｒ）## EQU1 ## Vout = Vr- (id + Δid) × (R + r + Δr)
【００１７】[0017]
【数２】Δｉｄ＝ｉｄ×α（ｔ−２５）## EQU2 ## Δid = id × α (t-25)
【００１８】[0018]
【数３】Δｒ＝ｒ×β（ｔ−２５） ここで、Ｖｒはオペアンプ＋入力に入力されている基準
電圧，ｉｄはフォトダイオード温度２５℃でのフォトダ
イオード電流，αはフォトダイオード電流の単位温度変
化率，ｔはフォトダイオード温度，Ｒは抵抗１５の抵抗
値，ｒは２５℃でのチップ型ＮＴＣサーミスタの抵抗
値，βはチップ型ＮＴＣサーミスタ抵抗値の単位温度変
化率である。## EQU3 ## Δr = r × β (t-25) where Vr is the reference voltage input to the operational amplifier + input, id is the photodiode current at the photodiode temperature of 25 ° C., and α is the unit of the photodiode current. Temperature change rate, t is the photodiode temperature, R is the resistance value of the resistor 15, r is the resistance value of the chip type NTC thermistor at 25 ° C., and β is the unit temperature change rate of the chip type NTC thermistor resistance value.
【００１９】次に、Δｉｄ×Δｒ＝０として数式１を展
開するとすると、数式４となる。Next, when Formula 1 is expanded with Δid × Δr = 0, Formula 4 is obtained.
【００２０】[0020]
【数４】Ｖｏｕｔ＝Ｖｒ−ｉｄ×（Ｒ＋ｒ）−Δｉｄ×
（Ｒ＋ｒ）−ｉｄ×Δｒ また、フォトダイオード３の温度によらず出力電圧Ｖｏ
ｕｔを一定にするためには上の数式４より、数式５が得
られる。## EQU00004 ## Vout = Vr-id.times. (R + r)-. DELTA.id.times.
(R + r) −id × Δr Further, the output voltage Vo does not depend on the temperature of the photodiode 3.
In order to keep ut constant, Equation 5 is obtained from Equation 4 above.
【００２１】[0021]
【数５】−Δｉｄ×（Ｒ＋ｒ）−ｉｄ×Δｒ＝０ さらに数式５，数式２，数式３より、数式６となるよう
にチップ型ＮＴＣサーミスタ２の抵抗値と単位温度変化
率と抵抗１５の抵抗値を設定すればよい。## EQU00005 ## -.DELTA.id.times. (R + r) -id.times..DELTA.r = 0 Further, from the formula 5, the formula 2, and the formula 3, the resistance value of the chip-type NTC thermistor 2, the unit temperature change rate, and the resistance 15 The resistance value may be set.
【００２２】[0022]
【数６】β＝−α×（１＋Ｒ／ｒ） この様に半導体レーザ１内のフォトダイオード３にチッ
プ型ＮＴＣサーミスタ２を設け、フォトダイオード電流
を電圧に変換する抵抗１５と前記チップ型ＮＴＣサーミ
スタ２を直列に接続し、フォトダイオード３の温度に応
じて電流−電圧変換効率を変えることにより半導体レー
ザ１の自己発熱や周囲温度の影響によるレーザ光量検出
値の変動を減少させ、精度の良いレーザ光量制御を可能
にする。 （実施例２）本発明の第２の実施例を図面に基づいて説
明する。図５は半導体レーザ１の光量検出するための検
出回路を含めた光量制御回路１３であり、フォトダイオ
ード３からの電流をフォトダイオード３に設けられたチ
ップ型サーミスタ２と抵抗１５によって電圧変換し、変
換された電圧をオペアンプ１４を介してレーザドライブ
回路１６に検出光量値として送られる。[Equation 6] β = −α × (1 + R / r) Thus, the chip NTC thermistor 2 is provided in the photodiode 3 in the semiconductor laser 1, and the resistor 15 for converting the photodiode current into a voltage and the chip NTC thermistor. 2 are connected in series, and the current-voltage conversion efficiency is changed according to the temperature of the photodiode 3 to reduce the fluctuation of the laser light amount detection value due to the self-heating of the semiconductor laser 1 and the influence of the ambient temperature, and the laser with high accuracy can be obtained. Enables light intensity control. (Embodiment 2) A second embodiment of the present invention will be described with reference to the drawings. FIG. 5 shows a light amount control circuit 13 including a detection circuit for detecting the light amount of the semiconductor laser 1. The current from the photodiode 3 is converted into a voltage by a chip type thermistor 2 and a resistor 15 provided in the photodiode 3, The converted voltage is sent as a detected light amount value to the laser drive circuit 16 via the operational amplifier 14.
【００２３】ここで、前記オペアンプ１４の出力電圧
（Ｖｏｕｔ）は以下の数式７，８，９の様に表わされ
る。Here, the output voltage (Vout) of the operational amplifier 14 is expressed by the following equations 7, 8 and 9.
【００２４】[0024]
【数７】 Ｖｏｕｔ＝（ｉｄ＋Δｉｄ）×（Ｒ＋ｒ＋Δｒ）(7) Vout = (id + Δid) × (R + r + Δr)
【００２５】[0025]
【数８】Δｉｄ＝ｉｄ×α（ｔ−２５）## EQU8 ## Δid = id × α (t-25)
【００２６】[0026]
【数９】Δｒ＝ｒ×β（ｔ−２５） ここで、Δｉｄ×Δｒ＝０として数式７を展開すると、
数式１０となる。## EQU9 ## Δr = r × β (t-25) Here, when Formula 7 is expanded with Δid × Δr = 0,
Equation 10 is obtained.
【００２７】[0027]
【数１０】Ｖｏｕｔ＝ｉｄ×（Ｒ＋ｒ）＋Δｉｄ×（Ｒ
＋ｒ）＋ｉｄ×Δｒ また、フォトダイオード３の温度によらず出力電圧Ｖｏ
ｕｔを一定にするためには上の数式７より、数式１１を
得て、[Equation 10] Vout = id × (R + r) + Δid × (R
+ R) + id × Δr Further, the output voltage Vo does not depend on the temperature of the photodiode 3.
In order to make ut constant, Equation 11 is obtained from Equation 7 above,
【００２８】[0028]
【数１１】Δｉｄ×（Ｒ＋ｒ）＋ｉｄ×Δｒ＝０ さらに数式７，８，９より、数式１２となるようにチッ
プ型ＮＴＣサーミスタ２の抵抗値と単位温度変化率と抵
抗１５の抵抗値を設定すればよい。[Expression 11] Δid × (R + r) + id × Δr = 0 Further, from Expressions 7, 8, and 9, the resistance value of the chip-type NTC thermistor 2, the unit temperature change rate, and the resistance value of the resistance 15 are set so as to be Expression 12. do it.
【００２９】[0029]
【数１２】β＝−α×（１＋Ｒ／ｒ） この様に半導体レーザ１内のフォトダイオード３にチッ
プ型ＮＴＣサーミスタ２を設け、フォトダイオード電流
を電圧に変換する抵抗１５と前記チップ型ＮＴＣサーミ
スタ２を直列に接続し、フォトダイオード３の温度に応
じて電流−電圧変換効率を変えることにより半導体レー
ザの自己発熱や周囲温度の影響によるレーザ光量検出値
の変動を減少させ、精度の良いレーザ光量制御を可能に
する。[Equation 12] β = −α × (1 + R / r) As described above, the chip NTC thermistor 2 is provided in the photodiode 3 in the semiconductor laser 1, and the resistor 15 for converting the photodiode current into a voltage and the chip NTC thermistor. 2 are connected in series, and the current-voltage conversion efficiency is changed according to the temperature of the photodiode 3 to reduce the fluctuation of the laser light amount detection value due to the self-heating of the semiconductor laser and the influence of the ambient temperature, and the accurate laser light amount. Allow control.
【００３０】[0030]
【発明の効果】本発明は以上の構成及び作用を有するも
ので、レーザ光量を検出する受光素子に温度検出手段を
設け、受光素子の温度に応じて光量検出値に補正を加え
ることにより半導体レーザの自己発熱や周囲温度の影響
によるレーザ光量検出値の変動を減少させ、精度の良い
レーザ光量の制御を可能とする。According to the present invention having the above-mentioned structure and operation, a semiconductor laser is provided by providing a temperature detecting means in a light receiving element for detecting the amount of laser light, and correcting the light amount detection value according to the temperature of the light receiving element. It is possible to reduce the fluctuation of the laser light amount detection value due to the self-heating of the device and the influence of the ambient temperature, and to control the laser light amount with high accuracy.
【図１】図１は第１実施例の半導体レーザの構成図。FIG. 1 is a configuration diagram of a semiconductor laser according to a first embodiment.
【図２】図２は第１実施例の制御回路図。FIG. 2 is a control circuit diagram of the first embodiment.
【図３】図３はフォトダイオード温度特性図。FIG. 3 is a photodiode temperature characteristic diagram.
【図４】図４はフォトダイオード温度特性図。FIG. 4 is a photodiode temperature characteristic diagram.
【図５】図５は第２実施例制御回路図。FIG. 5 is a control circuit diagram of a second embodiment.
【図６】図６は従来の半導体レーザの構成図。FIG. 6 is a block diagram of a conventional semiconductor laser.
１ 半導体レーザ ２ サーミスタ（温度検出手段） ３ フォトダイオード（受光素子） ４ レーザチップ（レーザ発光素子） １３ レーザ光量制御回路 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Thermistor (temperature detection means) 3 Photodiode (light receiving element) 4 Laser chip (laser light emitting element) 13 Laser light amount control circuit
Claims (3)
ら発光されたレーザ光の一部を受光する受光素子とを備
え、レーザ発光量を前記受光素子の光量検出値を用いて
制御する半導体レーザにおいて、 前記受光素子に温度を検出する温度検出手段を設けたこ
とを特徴とする半導体レーザ。1. A semiconductor laser comprising a laser light emitting element and a light receiving element for receiving a part of laser light emitted from the laser light emitting element, and controlling the laser light emission amount by using a light amount detection value of the light receiving element. A semiconductor laser, wherein the light receiving element is provided with a temperature detecting means for detecting a temperature.
出値に、この温度検出手段の検出温度に応じて前記光量
検出値に補正を加えることを特徴とする光量検出回路。2. A light amount detection circuit for correcting the light amount detection value of a light receiving element provided with temperature detection means, according to the temperature detected by the temperature detection means.
ら発光されたレーザ光の一部を受光する受光素子とを備
え、レーザ発光量を前記受光素子の受光量を用いて制御
する半導体レーザにおいて、 前記受光素子の温度を検出する温度検出手段を設け、こ
の温度検出手段の検出温度に応じて光量検出値に補正を
加える光量検出回路によりレーザ発光量を制御すること
を特徴とする半導体レーザ。3. A semiconductor laser comprising a laser light emitting element and a light receiving element for receiving a part of laser light emitted from the laser light emitting element, wherein the laser light emission amount is controlled by using the light receiving amount of the light receiving element. A semiconductor laser characterized in that temperature detection means for detecting the temperature of the light receiving element is provided, and the laser emission amount is controlled by a light amount detection circuit for correcting the light amount detection value according to the temperature detected by the temperature detection means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30262394A JPH08139395A (en) | 1994-11-14 | 1994-11-14 | Semiconductor laser and light quantity detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30262394A JPH08139395A (en) | 1994-11-14 | 1994-11-14 | Semiconductor laser and light quantity detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08139395A true JPH08139395A (en) | 1996-05-31 |
Family
ID=17911221
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30262394A Withdrawn JPH08139395A (en) | 1994-11-14 | 1994-11-14 | Semiconductor laser and light quantity detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08139395A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7907650B2 (en) | 2005-03-31 | 2011-03-15 | Eudyna Devices Inc. | Laser module, control method of the same, control data of the same, and control data generation method |
| US11067139B2 (en) | 2017-06-30 | 2021-07-20 | Honda Motor Co., Ltd | Vehicle transmission system |
-
1994
- 1994-11-14 JP JP30262394A patent/JPH08139395A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7907650B2 (en) | 2005-03-31 | 2011-03-15 | Eudyna Devices Inc. | Laser module, control method of the same, control data of the same, and control data generation method |
| US11067139B2 (en) | 2017-06-30 | 2021-07-20 | Honda Motor Co., Ltd | Vehicle transmission system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20020115 |