JPS5919252A - Control method of semiconductor laser array output - Google Patents

Abstract

PURPOSE:To eliminate the effect due to the characteristic variance of each semiconductor laser, by modulating each semiconductor laser of a semiconductor laser array for each main scanning and in a period containing no information signal, then detecting the modulated output through a photodetector, and controlling the output of each semiconductor laser with the output signal of the photodetector. CONSTITUTION:Semiconductor lasers 231, 232 and 233 are modulated by modulating b1, b2 and b3 with the 1st, 2nd and 3rd main scans respectively. Thereafter, the same modulation is repeated. A photodetector 31 detects the outputs of lasers 231-233 and amplifies them through an amplifier 32. Sampling/holding circuits 33-35 sample and hold the output signals of the amplifier 32 synchronously with the signals b1-b3 and by sampling signals produced in a due generating period. The output signals of the circuits 33-35 are compared with the reference voltage through error amplifiers 36-38. Then the error signals are applied to driving circuits 39-41, and these circuits drive the lasers 231-233 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor laser array output suppression method in a news recording method using a semiconductor laser array as a light source.

Conventionally, a single semiconductor laser was used (in optical information recording devices, the output of the semiconductor laser was controlled by detecting the monitor output of the semiconductor laser). However, since this optical information recording device uses a single semiconductor laser, the recording speed cannot be increased. In addition, in an optical information recording device using a semiconductor laser array, one output out of multiple outputs of the semiconductor laser array is detected and the total output of the semiconductor laser array is kept constant.
A method has been adopted to do so. However, in this method, since the semiconductor laser array has variations of 11% from the semiconductor lasers and others, it is difficult to set the outputs of all the semiconductor lasers to a constant value.

The present invention improves the above-mentioned drawbacks and provides a semiconductor racer 1.
The purpose of this invention is to provide a semiconductor laser array output control method that can be implemented using a simple circuit, since the effects of custom-made variations are less than 7'x.

Embodiments of the present invention will be described below with reference to the drawings.

3□ Figure 1 shows an example of an optical information recording device using a single semiconductor laser. The modulation circuit 1 has a half-coupled laser 2 ker ii due to the input from the single child q4
'・'' is output from the semiconductor racer 2.

The laser beam modulated according to the character l'A#; tM is converted into parallel light with a beam diameter of >E by a cut-off lens 3, and is converted into a parallel beam using the diffraction phenomenon of a rotating polygonal sharpness or a porogram)-to an optical system 4. j at a constant speed in the main direction
I feel gravity. During this run, the laser chip from the optical system 4 is formed as a spot on the recording medium 6 by the photoreceptor drum, which is rotated once by the J·θ angle 5.
Character information is recorded on the record body 6.

In order to improve the low speed of the optical information recording device using this +≠- semiconductor laser, a plurality of half-folds were used.
A semi-υ-h body laser array arrayed in a solar cell has been developed.

Figure 4'2 shows an example of a semiconductor laser array.

This one-tally is a 31-layer semiconductor laser array, and is made of n-Ga(% 11 + n-GaAs substrate 12.n-Ga1-y Aly As 13, G
a1-x A7x As (x<y) 14゜P -
Ga1-y AlyAs 15, P 41.6
It is made of 4Q construction (a little more nostalgic for the issue), which is constructed with racer chips laminated with 1 to 1.65', but I will omit that explanation). This laser chip (
In order to improve the aisles of the 13 semiconductor lasers, loads 17 and 18 are provided, and each semiconductor laser emits laser light from light emitting parts] 9 to 21. Then, the racer chip is glued to the surf mount part 22 with In or the like with the yoke facing down.

Each of the semiconductor lasers in this semi-integrated laser array can be independently driven and modulated, and at the same time, information can be transmitted as optical signal 16.

An example of an optical recording device using such a semi-integrated laser array is shown in Fig. 1 ('3.Each semiconductor laser 231 to 233 of the semi-integrated laser array 23 is not shown or is driven by an independent drive circuit). Driven fan 1 and modulation circuit 1
Modulated by Rogo. Semiconductor lasers 231-235
The racer who was a mountain man and -11 are a match! The l/l lens forms parallel lights, but these parallel lights have different angles to the optical axis of the objective lens 24. versus! The focal short shelf of the nose/zu 24 is J-1, each half-fathom body is 231-2
If the 350-degree corner is d, then the angle difference Δθ of the valley parallel light exiting the objective lens 24 is 11. Each parallel beam C from the objective lens 24 is polarized by a scanning optical system 25 consisting of a rotating polygon. In Figure 3, only the reflective surface of the rotary polygon inkstone 25 is shown.

The valley parallel light deflected by the 10-turn multifaceted sharp 25 is imaged as an independent spot by the JO lens 26 on a recording medium 27 consisting of a photosensitive drum which is turned by 1".
l.

Along with the 250 rotations of the rotating multifaceted blade, information is recorded on the optical drum 27 in the vertical direction in FIG. The interval △ of the spots for main running is JO lens 26
When the focal length is f2, it becomes 1, t2 □ d 1 , and the distance between the traveling spots is equal to the distance d between the semiconductor lasers multiplied by h/f+. (f,=l.

mmr h = 200 mm, d = = 10
If it is μm, it becomes 622111m, which is 2 mm
This means that the 161 spots are spaced at intervals of 3 (161 spots in a direction perpendicular to the direction in which they are arranged).If information is recorded in this state, each scanning line will be As a solution to this problem, as shown in Figure 6, it is possible to set an angle θ of about 1, which is about 7 inches in the direction of the sub-stroke force in the arrangement direction of the semiconductor lasers 231 to 230. It's here.

By doing this, a main rectangular tatami with good spacing in the direction of the secondary crucible can be created. If the distance between Rr women's races and races in the sub-race direction is 1, it is good to set φ”'S11 − △. Each semiconductor racer 231 to 235 is not modulated independently with poor line information. Fang 1's first lap was recorded at the same time as the main line for one lap of the semi-conductor racer.

Figures 3 and 4 are examples of the circuit of the present invention, and Figures 5 and 5 are timing charts thereof. In this example, the optical system is configured so that all the output monitor lights from the semiconductor lasers 231 to 23 are directed toward the photodetector 31 at the 4th position. "do. ”・5
Figures (a), (b), and (-) indicate semiconductor racers 231 to 23.
6 output fltll bait 1 and modulation No. 18 a, b1 to b5 for beam position detection, which are generated during the braking/g period when there is no alert signal. The half-containing body racer Z31 is modulated by the modulation signal a in the modulation circuit for each ten-stroke interval, and its output is detected by the optical detector j↓'1 device 31.
So, j! , Bi-width fan 1, and rotary polygon head 25 correspond to the output signal of semiconductor lasers 231 to 236 for modulating with information signals. Further, the semiconductor lasers 2; 31 to 236 are sequentially modulated by the modulation circuit according to the same signals b1 to b3. In other words, at the first stop, the semiconductor laser 231 modulates the modulation signal b1, and at the second stop, the laser 232 modulates the modulation signal b2. From time to time, semiconductor laser 233
is modulation No. 16 b5 (:'!IL@SIL, similar modulations will be repeated thereafter).

Figures 2 and 5 (d), (e), and (f) are modulation signals for 1 o'clock in which the 1 hour signal 1' symbol C is 4, and the semiconductor lasers 231 to 236 are modulated by the modulation circuit. The photodetector 31 detects the outputs of the semiconductor racers 231 to 233 and generates a false signal as shown in Figure 5 (G). and this output signal is sent to amplifier 3.
It is amplified by 2.

The pre-knob hold circuits 33 to 35 receive modulation signals b1 to
Figure 5 of the Zuru that occurs in the period of occurrence in synchronization with b3 (H)
('J) The output signal of the amplifier 32 is held by the Sanoprinog signal as shown in (J). In other words, the output signal from the amplifier 32 is modulated by the modulation signal b1 of the semiconductor laser 231, and the output signal from the amplifier 32 is modulated by the output signal b1.
The modulation signal b of the semiconductor laser 232 is obtained from the output signal of the semiconductor laser 232.
2, sample and hold the part corresponding to the 11 output, and the S/Prifugal bold circuit 35
2 is modulated by the variable W11 signal b3 of the semiconductor laser 235, and the >; ij portion corresponding to the output is held. The 7 pull-hold circuit,
Outputs of 33 to 35 (g is the error for each) 1 stomach 1 suspension, 3
H ~ 38 & Compare with ``Kametsu'' 1 part 4
One piece of Sahakugo is added to Kin circuits 39-41. , 1 time 1-a39~41 is 1 semiconductor laser 2
31-233 Kaoru is driving, but the driving type is 77! i is 1tll @l due to the output signals of the error amplifiers 36 to 38
I'll do it. Therefore, Zanoprinog bold circuits 33-35
The outputs of the semiconductor lasers 231 to 233 are controlled to be constant so that the outputs of the semiconductor lasers 231 to 233 are always controlled to be equal to the reference voltage.

As described above, according to the present invention, the fan 1 is changed one by one for each semiconductor laser in the semiconductor layer array during the absence of the Q, 1, and K signals in the optical information recording device. The output τ light (detected by the volcanic device and the output of this light extractor (
, q controls the output of each semiconductor laser, so
There is no influence from variations in the customization of each semi-conductor racer, and IL is simpler than that of a gift that separately detects and controls the valley output of a semiconductor racer! It can be carried out with lE.

[Brief explanation of the drawing]

Figure 3.1 is a perspective view showing an example of an optical information recording device;
The figure is a perspective view showing part 1j of the semiconductor racer array,
Figure 3.3 is a schematic front view showing another example of optical information recorder, 1
・Figure 4 shows an example of the implementation circuit of the present invention] J-Suz block diagram.
・Figure 5 is a timing chart for the same side, and Figures 1' and 6 are diagrams for explaining the present invention. 231-233...Semiconductor racer, 31...Photodetector. 32...Amplifier, 33-35...S/Griffuge hold circuit, 36-38...Error amplifier, 39-4
1... Drive circuit. The fourth garden is also G darkness

Claims (1)

[Claims] In an optical information recording device that records a news report by placing an Oh laser beam emitted from a semiconductor laser onto a moving recording medium and modulating the laser beam with a news signal, during a period when there is no silver signal, +: The output signal of the semiconductor laser is modulated one by one for each semiconductor laser in the iJ semiconductor laser array, and the output signal of this photodetector is used to detect the output signal of the semiconductor laser. It is special to control the semiconductor laser play output for 1 hour and 1 hour.