Semiconductor laser drive device and image recording device
AssigneeFuji Xerox Co., Ltd.
InventorChikaho Ikeda
Life of this patent
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Abstract
The present invention relates to a semiconductor laser drive device, and an image recording device whose function includes scanning a predetermined body to be scanned with a laser beam carrying image information in the course of recording an image, and which makes high speed image regeneration while maintaining a high quality of the image, wherein the devices are equipped with a first feedback circuit including a first operational amplifier and a second feedback circuit including a second operational amplifier, so that the double feedback can concurrently be effected to obtain current vs. light output characteristics with a high speed and high accuracy in an analog mode.
Claims6
A semiconductor laser drive device comprising:
- a drive current source supplying a drive current, which is the drive current having a magnitude corresponding to a first set value, and whose gain is adjusted according to a gain control value to a semiconductor laser;
- a bias current source supplying a bias current corresponding to a current control value to said semiconductor laser;
- a monitor value generating circuit generating a monitor value which is obtained by adding a first monitor value, which is the first monitor corresponding to a second set value, and whose gain is adjusted according to said gain control value, to a second monitor value corresponding to said current control value;
- a first feedback circuit supplying a current to said bias current source and to said monitor value generating circuit, wherein a light emission quantity monitor signal, which is obtained by monitoring a light emission quantity of said semiconductor, and a predetermined first reference value are input and said current control value is generated so as to emit a light emission quantity corresponding to the first reference value from the semiconductor laser;
- and
- a second feedback circuit supplying a current to said drive current source and to said monitor generating circuit, wherein a monitor value which is generated in said monitor generating circuit and a predetermined second reference value are input and the gain control value is generated so as to generate the monitor value corresponding to said second reference value.
An image recording device according to the present invention achieving an above-mentioned object is an image recording device whose function includes a step to scan a predetermined body to be scanned with a laser beam carrying image information in the course of recording an image, comprising:
- a semiconductor laser emitting a laser beam;
- a photosensor generating a light emission quantity monitor signal by monitoring a light emission quantity of said semiconductor laser;
- a semiconductor laser drive unit supplying a current to said semiconductor laser;
- a scanning optical system scanning a predetermined body to be scanned by a laser beam emitted from said semiconductor laser, and
- said semiconductor laser drive unit comprising:
- a drive current source supplying a drive current, which is the drive current having a magnitude corresponding to a first set value, and whose gain is adjusted according to a gain control value to a semiconductor laser;
- a bias current source supplying a bias current corresponding to a current control value to said semiconductor laser;
- a monitor value generating circuit generating a monitor value which is obtained by adding a first monitor value, which is the first monitor corresponding to a second set value, and whose gain is adjusted according to said gain control value, to a second monitor value corresponding to said current control value;
- a first feedback circuit supplying a current to said bias current source and to said monitor value generating circuit, wherein alight emission quantity monitor signal, which is obtained by monitoring a light emission quantity of said semiconductor, and a first reference value are input and said current control value is generated so as to emit a light emission quantity corresponding to said first reference value from said semiconductor laser;
- and
- a second feedback circuit supplying a current to said drive current source and to said monitor generating circuit, wherein a monitor value which is generated in said monitor generating circuit and a second reference value are input and said gain control value is generated so as to generate said monitor value corresponding to said second reference value.
Dependencies are inferred from the claim text.