JPS63213983A - Device for controlling output of semiconductor laser - Google Patents
Device for controlling output of semiconductor laserInfo
- Publication number
- JPS63213983A JPS63213983A JP4819587A JP4819587A JPS63213983A JP S63213983 A JPS63213983 A JP S63213983A JP 4819587 A JP4819587 A JP 4819587A JP 4819587 A JP4819587 A JP 4819587A JP S63213983 A JPS63213983 A JP S63213983A
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor laser
- output
- circuit
- correction
- currents
- 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.)
- Granted
Links
- 239000004065 semiconductor Substances 0.000 title claims abstract description 93
- 230000003287 optical effect Effects 0.000 claims description 15
- 239000003990 capacitor Substances 0.000 abstract description 8
- 239000000872 buffer Substances 0.000 abstract description 7
- 238000010586 diagram Methods 0.000 description 11
- 108091008695 photoreceptors Proteins 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 238000003708 edge detection Methods 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 3
- 230000004069 differentiation Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/062—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes
- H01S5/06209—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium by varying the potential of the electrodes in single-section lasers
- H01S5/06216—Pulse modulation or generation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
- H01S5/042—Electrical excitation ; Circuits therefor
- H01S5/0427—Electrical excitation ; Circuits therefor for applying modulation to the laser
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
- H01S5/042—Electrical excitation ; Circuits therefor
- H01S5/0428—Electrical excitation ; Circuits therefor for applying pulses to the laser
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
- H01S5/06808—Stabilisation of laser output parameters by monitoring the electrical laser parameters, e.g. voltage or current
Abstract
Description
【発明の詳細な説明】
（技術分野）
本発明はレーザプリンタ、レーザファックス等に用いら
れる半導体レーザ出力制御装置に関する。DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a semiconductor laser output control device used in laser printers, laser fax machines, and the like.
（従来技術）
従来、半導体レーザ出力制御装置としては半導体レーザ
の光出力を光検出回路で検出してコンパレータで基準値
と比較し、この結果によりアップダウンカウンタをアシ
プカウン１〜又はダウンカウントさせてそのカウント値
に応じた電流を半導体レーザに流すものが知られている
。(Prior art) Conventionally, as a semiconductor laser output control device, the optical output of the semiconductor laser is detected by a photodetection circuit, and compared with a reference value by a comparator, and based on this result, the up/down counter is caused to count down to 1 or more. A device is known in which a current is passed through a semiconductor laser according to a count value.
しかしこのような半導体レーザ出力制御装置では半導体
レーザはその熱結合により光出力が変動するので、半導
体レーザの光出力を検出して半導体レーザの駆動電流を
調整しその駆動電流を一定に保っても半導体レーザの発
光時（立上り時）の光出力が半導体レーザの駆ｗＪ電流
値によって定まる光出力より大きくなっである時定数で
設定値に落ち着く。例えば半導体レーザを第・１図に示
すような変調信号でオン／オフさせた場合半導体レーザ
の光出力は第４図に示すように変動する。この半導体レ
ーザの出力変動は半導体レーザ使用のレーザプリンタ等
において画像の濃度ムラとなって現われたり、画像のハ
ーフト−ンを忠実に再現できなくなったりする原因とな
る。However, in such a semiconductor laser output control device, the optical output of the semiconductor laser fluctuates due to its thermal coupling, so even if the optical output of the semiconductor laser is detected and the driving current of the semiconductor laser is adjusted to keep the driving current constant. When the optical output of the semiconductor laser at the time of emission (rise) becomes larger than the optical output determined by the driving current value of the semiconductor laser, it settles to a set value with a certain time constant. For example, when a semiconductor laser is turned on/off using a modulation signal as shown in FIG. 1, the optical output of the semiconductor laser changes as shown in FIG. 4. This fluctuation in the output of the semiconductor laser causes uneven density of images in laser printers using semiconductor lasers, and the inability to faithfully reproduce halftones of images.
（目 的）
本発明は上記欠点を改善し、半導体レーザの出力変動を
抑えることができる半導体レーザ出力制御装置を提供す
ることを目的とする。(Objective) It is an object of the present invention to provide a semiconductor laser output control device that can improve the above-mentioned drawbacks and suppress output fluctuations of a semiconductor laser.
（構 成）
本発明は変調信号により半導体レーザをオン／オフさせ
てこの半導体レーザの光出力が一定になるようにこの半
導体レーザの駆動？！流を制御する半導体レーザ出力制
御装置において、補正手段を設けたものであり、この補
正手段は上記半導体レーザのオン時に上記半導体レーザ
に所定の時定数の補正電流を供給して上記半導体レーザ
の出力変動を補正する。(Structure) The present invention turns the semiconductor laser on and off using a modulation signal to drive the semiconductor laser so that the optical output of the semiconductor laser is constant. ! A semiconductor laser output control device for controlling a current, which is provided with a correction means, which supplies a correction current with a predetermined time constant to the semiconductor laser when the semiconductor laser is turned on, thereby adjusting the output of the semiconductor laser. Correct for fluctuations.
次に図面を参照しながら本発明の実施例について説明す
る。Next, embodiments of the present invention will be described with reference to the drawings.
まず、第３図に示す半導体レーザ出力制御装置の一例に
ついて説明する。First, an example of the semiconductor laser output control device shown in FIG. 3 will be described.
半導体レーザ１はレーザプリンタに光源として用いられ
るもので、その後方に出射した光出力がフォトダイオー
ドからなる光検出器２で検出される。フォトダイオード
２は半導体レーザ１の光出力に比例した電流を発生し、
この電流が増幅器３により電圧に変換されて比較器４で
基準電圧Ｖｒｅｆと比較される。比１Ｉ１２器４の出力
電圧は比較器４の両入力電圧の大小関係により高レベル
又は低レベルとなり、アップダウンカウンタ５のカウン
トモードを制御する６例えば半導体レーザ１の光出力が
基準値より小さい時には比較器４の出力が低レベルにな
り、アップダウンカウンタ５がアップカウントモードに
なる。非感光体走査信号はレーザプリンタにおいて半導
体レーザ１の光出力が感光体を走査していない時に発生
し半導体レーザ１の光出力で感光体を走査して画像記録
を行う時には消滅する（ご号であり、その立上りでフリ
ップフロップ６をセットする。このフリップフロップ６
の出力信号によりアンドゲート７が開いて非感光体走査
信号がアップダウンカウンタ５に送られ、アップダウン
カウンタ５がディスエーブル状態を解除されてクロック
をアップカウントする。このアップダウンカウンタ５の
出力はデジタル／アナログ変換器８によりアナログ量に
変換され、半導体レーザ駆動回路１０に加えられる。半
導体レーザ駆動回路１０はビデオ信号を含む変調信号が
入力され、この変調信号により半導体レーザｌをオン／
オフさせて変調すると共に入力信号に応じた電流を半導
体レーザ１に供給する。したがってアップダウンカウン
タ５のカウント値が徐々に増加することにより半導体レ
ーザ１の光出力が徐々に増大し、増幅器３の出力電圧が
上昇する。感光体走査時には非感光体走査信号が無くな
ってアップダウンカウンタ５がディスエーブル状態とな
り、半導体レーザ１の出カニＡ整が未了なら中断される
。そして非感光体走査時には非感光体走査信号が発生し
てアップダウンカウンタ５がイネーブル状態となり、半
導体レーザｌの出力調整が再開される。この後比較器４
の出力が低レベルから高レベルに反転すると、エツジ検
出回路１２が比較器４の出力の立上りエツジを検出して
ブリップフロップ６をリセットし、アンドゲート７を閉
じさせてアップダウンカウンタ５をディスエーブル状態
に復帰させる。A semiconductor laser 1 is used as a light source in a laser printer, and the light output emitted to the rear thereof is detected by a photodetector 2 made of a photodiode. The photodiode 2 generates a current proportional to the optical output of the semiconductor laser 1,
This current is converted into a voltage by an amplifier 3 and compared with a reference voltage Vref by a comparator 4. The output voltage of the ratio 1I12 device 4 becomes a high level or a low level depending on the magnitude relationship between both input voltages of the comparator 4, and controls the count mode of the up/down counter 56. For example, when the optical output of the semiconductor laser 1 is smaller than the reference value, The output of the comparator 4 becomes low level, and the up/down counter 5 enters the up-count mode. The non-photoreceptor scanning signal is generated in a laser printer when the optical output of the semiconductor laser 1 is not scanning the photoreceptor, and disappears when the optical output of the semiconductor laser 1 is used to scan the photoreceptor and record an image. Yes, the flip-flop 6 is set at the rising edge.
The output signal opens the AND gate 7 and sends the non-photoreceptor scanning signal to the up/down counter 5, and the up/down counter 5 is released from the disabled state and counts up the clock. The output of the up/down counter 5 is converted into an analog quantity by a digital/analog converter 8 and applied to a semiconductor laser drive circuit 10. The semiconductor laser drive circuit 10 receives a modulation signal including a video signal, and turns on/off the semiconductor laser l using this modulation signal.
The semiconductor laser 1 is turned off and modulated, and a current corresponding to the input signal is supplied to the semiconductor laser 1. Therefore, as the count value of the up/down counter 5 gradually increases, the optical output of the semiconductor laser 1 gradually increases, and the output voltage of the amplifier 3 increases. During photoconductor scanning, there is no non-photoconductor scanning signal and the up/down counter 5 becomes disabled, and if the output adjustment of the semiconductor laser 1 is not completed, the process is interrupted. During non-photoreceptor scanning, a non-photoreceptor scanning signal is generated, the up/down counter 5 is enabled, and the output adjustment of the semiconductor laser 1 is restarted. After this comparator 4
When the output of is inverted from low level to high level, the edge detection circuit 12 detects the rising edge of the output of the comparator 4 and resets the flip-flop 6, causing the AND gate 7 to close and disabling the up/down counter 5. restore the condition.
よってアンプダウンカウンタ５はカウント値を保持し、
従って半導体レーザ１の駆動電流の大きさがそのまま保
持される。Therefore, the amplifier down counter 5 holds the count value,
Therefore, the magnitude of the drive current of the semiconductor laser 1 is maintained as it is.
また、アップダウンカウンタ５のディスエーブル状態が
解除された際に比較器４の出力が高レベルであればアッ
プダウンカウンタ５はダウンカウントモードになってク
ロックをダウンカウントする。よって半導体レーザ１の
駆動電流が減少し。Furthermore, if the output of the comparator 4 is at a high level when the disable state of the up/down counter 5 is released, the up/down counter 5 enters a down count mode and counts down the clock. Therefore, the driving current of the semiconductor laser 1 decreases.
増幅器３の出力が減少する。そして増幅器１１の出力が
基準電圧Ｖｒｅｆより小さくなって比較器４の出力が高
レベルから低レベルに反転すると、エツジ検出回路１２
が比較器４の出力の立上りエツジを検出してブリップフ
ロップ６をリセットし、アンドゲート７を閉じさせてア
ップダウンカウンタ５をディスエーブル状態に復帰させ
る。したがってアップダウンカウンタ５はカウント値を
保持し、半導体レーザ１の駆動電流の大きさがそのまま
保持される。ここにエツジ検出回路１２は比較器４の出
力が低レベルから高レベルに反転した時にのみフリップ
フロップ６をリセットするように構成してもよい。The output of amplifier 3 decreases. When the output of the amplifier 11 becomes smaller than the reference voltage Vref and the output of the comparator 4 is reversed from high level to low level, the edge detection circuit 12
detects the rising edge of the output of comparator 4 and resets flip-flop 6, causing AND gate 7 to close and returning up/down counter 5 to the disabled state. Therefore, the up/down counter 5 holds the count value, and the magnitude of the driving current of the semiconductor laser 1 is maintained as it is. Here, the edge detection circuit 12 may be configured to reset the flip-flop 6 only when the output of the comparator 4 is inverted from a low level to a high level.
第４図はこの半導体レーザ出力制御装置における半導体
レーザの出力状態を示し、半導体レーザの光出力が変動
している。FIG. 4 shows the output state of the semiconductor laser in this semiconductor laser output control device, and the optical output of the semiconductor laser is fluctuating.
第５図は上記半導体レーザ出力制御装置において補正手
段を設けた本発明の実施例における半導体レーザの出力
状態を示し、半導体レーザの光出力変動が補正される。FIG. 5 shows the output state of the semiconductor laser in an embodiment of the present invention in which a correction means is provided in the semiconductor laser output control device, and fluctuations in the optical output of the semiconductor laser are corrected.
第６図〜第８図は本発明の各実施例における補正手段を
示す。6 to 8 show correction means in each embodiment of the present invention.
第６図に示す補正手段は位相補正回路２１と微分回路２
２からなり、位相補正回路２１は半導体レーザ１の発光
（光出力）に対して補正を加えるタイミングを調整する
ものであってこのタイミング調整を必、要とする場合に
のみ設けられる。微分回路２２は半導体レーザ駆動回路
１０に入力される変調信号を微分することによって半導
体レーザ１のオン時に所定の時定数の補正電流を半導体
レーザｌに供給して半導体レーザ１の出力変動を補正す
る。The correction means shown in FIG. 6 includes a phase correction circuit 21 and a differentiation circuit 2.
2, the phase correction circuit 21 adjusts the timing of correcting the light emission (light output) of the semiconductor laser 1, and is provided only when this timing adjustment is necessary. The differentiating circuit 22 differentiates the modulation signal input to the semiconductor laser drive circuit 10 and supplies a correction current with a predetermined time constant to the semiconductor laser l when the semiconductor laser 1 is turned on, thereby correcting output fluctuations of the semiconductor laser 1. .
補正すべき半導体レーザ出力特性が１種ｍ（ｎ〉１）の
時定数をもつときには第７図、第８図に示すようにそれ
らの時定数及び補正量の合致した複数の微分回路２２．
２２１〜２２ｎを並列に設けるようにすればよい。When the semiconductor laser output characteristic to be corrected has a time constant of type 1 m (n>1), as shown in FIGS. 7 and 8, a plurality of differentiating circuits 22 whose time constants and correction amounts match are used.
221 to 22n may be provided in parallel.
上記微分回路２２．２２１〜２２ｎは第９図に示すよう
にコンデンサ２３及び抵抗２４からなるもの、第１Ｏ図
に示すようにコンデンサ２５及び抵抗２６．２７からな
るもの、第１１図に示すようにコンデンサ２８．演算増
幅器２９、抵抗３０〜３２からなるもの等を用いること
ができる。The differentiating circuits 22, 221 to 22n are composed of a capacitor 23 and a resistor 24 as shown in FIG. 9, a capacitor 25 and a resistor 26, 27 as shown in FIG. 1O, and a circuit as shown in FIG. Capacitor 28. An operational amplifier 29, resistors 30 to 32, etc. can be used.
本発明の実施例は変調信号を微分回路２２．２２１〜２
２ｎで微分して補正電流を作り半導体レーザの出力変動
を補正すると共に変調信号により半導体レーザ１をオン
／オフさせており、半導体レーザ出力変動を補正する系
Ａと、半導体レーザをオン／オフさせる系Ｂとが別々で
あって半導体レーザの点灯タイミングと出力変動の補正
タイミングとがずれてしまう。このずれ量が大きくなる
と、適性な半導体レーザ出力変動の補正がなされなくな
るので、半導体レーザ出力変動の補正開始と半導体レー
ザ点灯との適性タイミングを位相補正回路２１で調整す
る。この位相補正回路２１は例えば第１２図に示すよう
に変調信号をディレィライン３３で遅延させて上記系Ａ
の入力信号（位相遅れ信号）とし、かつ変′！Ａ信号を
そのまま上記系Ｂの入力信号（元信号）としてもよい。The embodiment of the present invention converts the modulated signal into differentiating circuits 22, 221 to 2.
A correction current is generated by differentiating by 2n, and the output fluctuation of the semiconductor laser is corrected, and the semiconductor laser 1 is turned on/off by a modulation signal, and the system A that corrects the semiconductor laser output fluctuation and the semiconductor laser are turned on/off Since the system B is separate from the system B, the lighting timing of the semiconductor laser and the timing for correcting output fluctuations are different from each other. If this amount of deviation becomes large, appropriate correction of the semiconductor laser output fluctuation cannot be performed, so the phase correction circuit 21 adjusts the appropriate timing between the start of correction of the semiconductor laser output fluctuation and the lighting of the semiconductor laser. This phase correction circuit 21 delays the modulation signal with a delay line 33 as shown in FIG.
input signal (phase delayed signal), and change ′! The A signal may be used as the input signal (original signal) of the system B as it is.
また位相補正回路２１は第１３図に示すようにバッファ
３４．抵抗３５、コンデンサ３６．シュミット回路３７
（又はバッファ３８）で構成してもよく、第１４図に示
すようにバッファ３９、抵抗４０、コンデンサ４１．コ
ンパＬ／−５４２ｙ＠抗４３゜４４で構成してもよく、
さらに第１５図に示すように複数のバッファ４５１〜４
５ｎで構成してもよい。Further, the phase correction circuit 21 includes a buffer 34. as shown in FIG. Resistor 35, capacitor 36. Schmitt circuit 37
(or a buffer 38), as shown in FIG. 14, a buffer 39, a resistor 40, a capacitor 41 . Compa L/-542y @ anti-43°44 may be configured,
Furthermore, as shown in FIG. 15, a plurality of buffers 451 to 4
It may be composed of 5n.
第１図は本発明の第１実施例における補正手段を示し、
第２図はその各部波形を示す。FIG. 1 shows a correction means in a first embodiment of the present invention,
FIG. 2 shows the waveforms of each part.
この第１実施例は上記半導体レーザ出力制御装置におい
て１位相補正回路２１、微分回路２２１〜２２３を設け
たものであり、トランジスタ４６〜４８．バッファ４９
．演算増幅器５０、抵抗５１〜５７は半導体レーザ駆動
回路を構成している。微分回路２２１〜２２３はそれぞ
れコンデンサ５８〜６０．トランジスタ６１〜６３゜抵
抗６４〜６９により構成され、変調信号が位相補正回路
２１により半導体レーザ駆動回路１０と微分回路２２１
〜２２３へ適当な位相関係に調整されて供給される。微
分回路２２１〜２２３は位相補正回路２１からの変調信
号を微分して互いに異なる時定数の補正信号を作り、半
導体レーザ駆動回路１０へ供給する。半導体レーザ駆動
回路１０では位相補正回路２１からの変調信号がバッフ
ァ４９を介してトランジスタ４８のベースに加えられて
半導体レーザ１をオン／オフさせると共に半導体レーザ
ｌへそのオン時にトランジスタ４６．４７により駆動電
流を供給し、この駆Ｉ電流が微分回路２２１〜２２３か
らトランジスタ４７のベースへの補正電流により補正さ
れる。In this first embodiment, a 1-phase correction circuit 21 and differentiating circuits 221 to 223 are provided in the semiconductor laser output control device described above, and transistors 46 to 48 . buffer 49
．． The operational amplifier 50 and the resistors 51 to 57 constitute a semiconductor laser drive circuit. Differentiating circuits 221-223 are connected to capacitors 58-60, respectively. It is composed of transistors 61 to 63 degrees and resistors 64 to 69, and the modulation signal is sent to the semiconductor laser drive circuit 10 and the differentiation circuit 221 by the phase correction circuit 21.
~223 are adjusted to have an appropriate phase relationship and supplied. The differentiating circuits 221 to 223 differentiate the modulation signal from the phase correction circuit 21 to create correction signals having mutually different time constants, and supply the correction signals to the semiconductor laser drive circuit 10. In the semiconductor laser drive circuit 10, the modulation signal from the phase correction circuit 21 is applied to the base of the transistor 48 via the buffer 49 to turn the semiconductor laser 1 on and off, and when the semiconductor laser l is on, it is driven by the transistors 46 and 47. A current is supplied, and this drive I current is corrected by a correction current from differentiating circuits 221 to 223 to the base of transistor 47.
この第１実施例では半導体レーザ１の駆動電流Ｉｏｐは
電源電圧をＶ、抵抗５１の値をＲ２とすればｔ＜４
で与えられ、ａ、ａｔａ位は抵抗５７の値をＲい抵抗５
７を流れる電流をＩｏとすれば（Ｆ点電位＋ＥｏＲ，＋
ｔＥＧ間電圧）で与えられる。Ａ点の変調信号によりＢ
。In this first embodiment, the drive current Iop of the semiconductor laser 1 is given by t<4, where the power supply voltage is V and the value of the resistor 51 is R2, and the values of the resistor 57 are R and the resistor 5 at positions a and ata is
If the current flowing through 7 is Io, then (F point potential +EoR, +
tEG voltage). B due to the modulation signal at point A
.
Ｃ，Ｄ点に各微分回路２２１〜２２３の抵抗６４．６６
、６８゜コンデンサ５８〜６０で決まる時定数の微分波
形が生ずる。これらのうち（−）方向に発生した波形に
よりトランジスタ６１〜６３はその波形に比例した電流
Ｉ、〜■ツをＥ点に流し、（＋）方向に発生した波形は
トランジスタ６１〜６３をカットオフにして何ら作用を
及ぼさない。Ｅ点に流れ込んだ電流■、〜工、はＩ。Resistance 64.66 of each differentiating circuit 221 to 223 at points C and D
, a differential waveform with a time constant determined by the 68° capacitors 58-60 is generated. Among these, the waveforms generated in the (-) direction cause the transistors 61 to 63 to flow currents I, ~■, proportional to the waveforms to point E, and the waveforms generated in the (+) direction cut off the transistors 61 to 63. It has no effect. The current flowing into point E is I.
を増加させてＧ点電位を上昇させ、Ｉｏｐを減少させる
。各工、〜工、は第２図の半導体レーザ出力波形から分
るように、半導体レーザ１の無補正時出力変動分■、■
、■をそれぞれ補正するように時定数及び電流量が設定
され、半導体レーザ１の出力変動が抑えられる。increases the G point potential and decreases Iop. As can be seen from the semiconductor laser output waveform in Fig. 2, each step, ~ step, is the uncorrected output fluctuation of the semiconductor laser 1 ■, ■
The time constant and the amount of current are set so as to correct , (2), respectively, and output fluctuations of the semiconductor laser 1 are suppressed.
第１６図は本発明の第２実施例における補正手段を示す
。FIG. 16 shows a correction means in a second embodiment of the present invention.
この第２実施例では上記第１実施例において。This second embodiment is similar to the first embodiment described above.
微分回路２２１〜２２３からの補正電流工、〜Ｉ、がＥ
点に流れ込んで抵抗５３の電流１４が増加し、Ｈ，Ｆ、
Ｇ点の電位が上昇してＩｏｐが減少する。各工、〜Ｉ、
は半導体レーザ１の無補正時出力変動分■〜■をそれぞ
れ補正するように時定数及び電流量が設定される。The correction currents, ~I, from the differentiating circuits 221 to 223 are E
The current 14 flowing into the resistor 53 increases, H, F,
The potential at point G increases and Iop decreases. Each work, ~I,
The time constant and current amount are set so as to respectively correct the uncorrected output fluctuations (1) to (2) of the semiconductor laser 1.
第１７図は本発明の第３実施例の補正手段を示す。FIG. 17 shows a correction means according to a third embodiment of the present invention.
この第３実施例は第１実施例において微分回路２２１〜
２２３からの補正電流１．〜１ちが１４点に流れ込んで
抵抗５５の電流ＩＳが増加し、Ｆ、Ｇ点の電位が上昇し
てＩｏｐが減少する。各Ｉ、〜■３は半導体レーザ１の
無補正時出力変動分■〜■をそれぞれ補正するように時
定数及び電流量が設定される。This third embodiment is different from the differentiating circuits 221 to 221 in the first embodiment.
Correction current from 223 1. ~1 flows into point 14, the current IS of the resistor 55 increases, the potentials at points F and G rise, and Iop decreases. The time constants and current amounts of each of I, .about.3, are set so as to correct the uncorrected output fluctuations of the semiconductor laser 1, .about.3, respectively.
（効 果）
以上のように本発明によれば半導体レーザのオン時に半
導体レーザに所定の時定数の補正電流を供給して半導体
レーザの出力変動を補正するので、半導体レーザの熱結
合による出力変動を安価で簡単な回路にて抑制すること
ができる。(Effects) As described above, according to the present invention, when the semiconductor laser is turned on, a correction current with a predetermined time constant is supplied to the semiconductor laser to correct output fluctuations of the semiconductor laser. can be suppressed with an inexpensive and simple circuit.
第１図は本発明の第１実施例の補正手段を示す回路図、
第２図は同第１実施例の各部波形を示す波形図、第３＠
は半導体レーザ出力制御装置の一例を示すブロック図、
第４図は同装置の半導体レーザ出力状態を示す波形図、
第５図は本発明の実施例の半導体レーザ出力状態を示す
波形図、第６図〜第８図は本発明の各実施例の補正手段
を示すブロック図、第９図〜第１１図は微分回路の各側
を示す回路図、第１２〜第１５図は位相補正回路の各側
を示す回路図、第１６図及び第１７図は本発明の第２実
施例及び第３実施例を示す回路図である。
２２、２２１〜２２ｎ・・・・微分回路や第６０FIG. 1 is a circuit diagram showing a correction means according to a first embodiment of the present invention;
Figure 2 is a waveform diagram showing the waveforms of each part of the first embodiment, and Figure 3
is a block diagram showing an example of a semiconductor laser output control device,
Figure 4 is a waveform diagram showing the semiconductor laser output state of the same device.
FIG. 5 is a waveform diagram showing the output state of a semiconductor laser according to an embodiment of the present invention, FIGS. 6 to 8 are block diagrams showing correction means in each embodiment of the present invention, and FIGS. 9 to 11 are differential diagrams. A circuit diagram showing each side of the circuit, FIGS. 12 to 15 are circuit diagrams showing each side of the phase correction circuit, and FIGS. 16 and 17 are circuit diagrams showing the second and third embodiments of the present invention. It is a diagram. 22, 221-22n... Differential circuit and 60th
Claims (1)
導体レーザの光出力が一定になるようにこの半導体レー
ザの駆動電流を制御する半導体レーザ出力制御装置にお
いて、上記半導体レーザのオン時に上記半導体レーザに
所定の時定数の補正電流を供給して上記半導体レーザの
出力変動を補正する補正手段を設けたことを特徴とする
半導体レーザ出力制御装置。In a semiconductor laser output control device that turns on/off a semiconductor laser using a modulation signal and controls a drive current of the semiconductor laser so that the optical output of the semiconductor laser is constant, 1. A semiconductor laser output control device comprising a correction means for correcting output fluctuations of the semiconductor laser by supplying a correction current with a time constant of .
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62048195A JP2612856B2 (en) | 1987-03-03 | 1987-03-03 | Semiconductor laser output control device |
| US07/243,119 US4835780A (en) | 1986-12-08 | 1988-09-07 | Semiconductor laser output control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62048195A JP2612856B2 (en) | 1987-03-03 | 1987-03-03 | Semiconductor laser output control device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63213983A true JPS63213983A (en) | 1988-09-06 |
| JP2612856B2 JP2612856B2 (en) | 1997-05-21 |
Family
ID=12796601
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62048195A Expired - Lifetime JP2612856B2 (en) | 1986-12-08 | 1987-03-03 | Semiconductor laser output control device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2612856B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014111354A (en) * | 2012-10-29 | 2014-06-19 | Canon Inc | Image formation apparatus |
| US10126675B2 (en) | 2014-05-16 | 2018-11-13 | Canon Kabushiki Kaisha | Image forming apparatus |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5961193A (en) * | 1982-09-30 | 1984-04-07 | Fujitsu Ltd | Drive circuit for laser diode |
| JPS6064853A (en) * | 1983-09-21 | 1985-04-13 | Hitachi Ltd | Driving system for laser diode |
| JPS62118590A (en) * | 1985-11-18 | 1987-05-29 | Fujitsu Ltd | Driving method for semiconductor laser |
| JPS6386589A (en) * | 1986-09-30 | 1988-04-16 | Ricoh Co Ltd | Output control equipment for semiconductor laser |
| JPS63209270A (en) * | 1987-02-25 | 1988-08-30 | Fuji Photo Film Co Ltd | Droop corrector for semiconductor laser |
-
1987
- 1987-03-03 JP JP62048195A patent/JP2612856B2/en not_active Expired - Lifetime
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5961193A (en) * | 1982-09-30 | 1984-04-07 | Fujitsu Ltd | Drive circuit for laser diode |
| JPS6064853A (en) * | 1983-09-21 | 1985-04-13 | Hitachi Ltd | Driving system for laser diode |
| JPS62118590A (en) * | 1985-11-18 | 1987-05-29 | Fujitsu Ltd | Driving method for semiconductor laser |
| JPS6386589A (en) * | 1986-09-30 | 1988-04-16 | Ricoh Co Ltd | Output control equipment for semiconductor laser |
| JPS63209270A (en) * | 1987-02-25 | 1988-08-30 | Fuji Photo Film Co Ltd | Droop corrector for semiconductor laser |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014111354A (en) * | 2012-10-29 | 2014-06-19 | Canon Inc | Image formation apparatus |
| US9482984B2 (en) | 2012-10-29 | 2016-11-01 | Canon Kabushiki Kaisha | Image forming apparatus for supplying and/or controlling correction current(s) to a laser |
| US10126675B2 (en) | 2014-05-16 | 2018-11-13 | Canon Kabushiki Kaisha | Image forming apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2612856B2 (en) | 1997-05-21 |
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