JPH09216409A - Light source unit and optical scanner using end-face luminescent semiconductor laser element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light source unit that is long has a high luminescent efficiency and reliability and allows a high speed printing, and an optical scanner using the light source unit. SOLUTION: This light source unit includes two or more end-face luminescent semiconductor laser elements 12a and 12b that are arranged so that the resonance direction becomes horizontal and mirrors 13 facing the end-face luminescent semiconductor laser elements 12a and 12b. The end-face luminescent semiconductor layer elements 12a and 12b are arranged in zigzag across the mirrors 13 on a mounting substrate and the mirrors 13 are inclined so that lights from the end-face luminescent type semiconductor laser elements 12a and 12b are led upward and the output lights are taken out in the vertical direction to the mounting substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device and an optical scanning device using an edge emitting semiconductor laser device, and more particularly, an image is formed by exposing and scanning an image carrier such as a laser beam printer or a laser beam copying machine. The present invention relates to those used for forming devices and the like.

[0002]

2. Description of the Related Art In a laser beam printer or a laser beam copying machine which forms a high density pixel by optical scanning of a modulated laser beam and records and outputs an image by an electrophotographic process, optical scanning is performed on an image carrier. In order to increase the speed, there is a first method of increasing the rotation speed of the polygon mirror used for optical scanning. Further, as a method of speeding up without using a laser, there is a second method of using a plurality of light emitting diodes and performing optical scanning in parallel corresponding to a scanning width.

[0003]

However, in such a conventional apparatus, the increase in the optical scanning speed depends on the mechanical performance such as the rotational speed of the polygon mirror. The increase in mechanical rotation speed deteriorates the life characteristics of the device and at the same time generates noise accompanying the rotation of the motor. Further, since the mechanical performance has a limit, there is a limit to the increase of the optical scanning speed. On the other hand, in the second method, a light emitting diode is used, and there is a problem that the light emitting diode has a lower luminous efficiency than a laser and the light output that can be taken out from each element is small.

When compared with a typical example, the light output on the surface to be scanned is 1/100 or less as compared with the laser. The minimum exposure required to form an image on the image carrier is determined by the product of the light output value and the exposure time. Therefore, if the light output is small, it is necessary to lengthen the exposure time accordingly, and the effect of parallel scanning for speeding up is offset. Further, since the light emission efficiency is low, heat generated during driving is also remarkable, and increasing the optical scanning speed may cause deterioration of the characteristics of the element due to heat.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light source device having a long length, high luminous efficiency, high-speed printing, and high reliability, and an optical scanning device using the same. To do.

[0006]

A feature of the present invention is that a plurality of edge-emitting semiconductor laser elements are arranged so that the resonance direction is horizontal, and the edge-emitting semiconductor laser elements are arranged to face each other. A light source device including a mirror, the edge emitting semiconductor laser elements are arranged on the mounting substrate in a zigzag pattern with the mirrors sandwiched therebetween, and the mirrors also face each other. The light from the die-type semiconductor laser device is guided upward, and the output light is inclined so as to be extracted in a direction perpendicular to the mounting substrate.

Preferably, the edge-emitting semiconductor laser device is composed of a laser array capable of emitting a plurality of laser beams simultaneously or independently.

It is also desirable that the mirror guides the light from the facing laser array upward corresponding to each laser array, and the output light is taken out in a line in a direction perpendicular to the mounting substrate. It is tilted like this.

More preferably, the plurality of edge emitting semiconductor laser devices and the mirror are monolithically arranged on the same substrate.

Further preferably, the plurality of edge emitting semiconductor laser elements include a photodetector on a surface opposite to the mirror, and the edge emitting semiconductor laser elements are output based on the output of the photodetector. And a feedback control means for adjusting the amount of light.

More preferably, the plurality of edge emitting semiconductor laser devices, the mirror and the photodetector are monolithically arranged on the same substrate.

A second feature of the present invention is that a plurality of edge-emitting type semiconductor laser elements configured so that the resonance direction is horizontal and mirrors arranged so as to face the edge-emitting type semiconductor laser elements. The edge emitting semiconductor laser elements are arranged on the mounting substrate in a zigzag pattern with the mirrors sandwiched therebetween, and the light from the edge emitting semiconductor laser elements facing each other is further provided. A light source device that is inclined so that the output light is taken out in a direction perpendicular to the mounting substrate, and a beam compression that compresses the light emitted from the light source device in a sub-scanning direction. An optical system, and a field lens for controlling the chief ray of the light beam from the beam compression optical system in a predetermined direction,
And an image forming optical system for condensing a light beam passing through the field lens onto a surface to be scanned and condensing the light beam, and driving the plurality of semiconductor laser elements simultaneously or independently. .

[0013]

According to the present invention, a plurality of semiconductor lasers having high luminous efficiency can be arranged corresponding to the scanning width, and the optical scanning device and the light source having high reliability while increasing the printing speed of a laser beam printer or the like. The device can be realized.

According to the first aspect of the present invention, since a plurality of semiconductor laser elements are arranged in a zigzag pattern with respect to the mirror,
Even in the case of high-density arrangement, a sufficient space for electrode wiring can be secured. Further, by arranging the mirrors in a zigzag manner, the spot rows of the light emitted from the light source device can be arranged in an arbitrary arrangement.

Further, by configuring the semiconductor laser device with a laser array, the scanning density can be greatly increased, and higher quality image formation can be performed.

Furthermore, by arranging so that the light extraction directions are in a line, it becomes possible to facilitate data processing when forming an image on the image bearing member, and it is long and has a high density. It is possible to provide a light source device.

Further, since the edge emitting semiconductor laser device and the mirror are monolithically arranged on the same substrate, adjustment such as alignment adjustment of the mirror is unnecessary, and the size of the entire apparatus can be reduced. When separating each element in each array, each laser element,
That is, if the high resistance region is formed by implanting ions such as protons into the region corresponding to the space between the laser stripes, each element is thermally connected, so that the variation in output due to the variation in temperature does not occur. Therefore, it is possible to obtain a highly uniformized output, and it is extremely reliable as a printer or a light source for exposing a photoconductor.

Further, the plurality of edge emitting semiconductor laser elements are provided with a photodetector on the surface opposite to the mirror, and the light amount of the edge emitting semiconductor laser elements is determined based on the output of the photodetectors. Since it is equipped with the feedback control means for adjusting, it becomes possible to easily cope with the temporal fluctuation of the light amount or to perform the intensity modulation. In addition, it is possible to satisfactorily adjust the light amount even when the characteristics are varied due to a rise in temperature.

Further, a plurality of edge emitting semiconductor laser devices, the mirror and the photodetector are provided on the same substrate,
Since they are arranged monolithically, adjustments such as alignment adjustment of the mirrors are not necessary, and the size of the entire device can be reduced.

Further, a beam compression optical system for compressing the light emitted from the light source device in correspondence with the sub-scanning direction, and a field lens for controlling the principal ray of the light beam from the beam compression optical system in a predetermined direction, Since the light flux passing through the field lens has an image forming optical system for condensing the light spot on the surface to be scanned, the plurality of semiconductor laser elements are driven simultaneously or independently, It is possible to dramatically improve the printing speed.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. 1 is a perspective view of a main part of a light source device according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view of the device.

This light source device is provided on the base substrate 11 with the first
Edge-emitting semiconductor laser elements 12a and second edge-emitting semiconductor laser elements 12b are arranged in a zigzag pattern, and the first and second mirror surfaces 13a and 13b are arranged in a zigzag pattern respectively corresponding to these. Placed mirror 13
And first and second photodetectors 14a and 14b respectively arranged outside the first and second edge-emitting semiconductor laser elements with respect to the mirror 13 and detecting the optical output of each laser element. The laser light is extracted in a direction perpendicular to the base substrate.

The outputs of the first and second photodetectors 14a and 14b are fed back to the drive circuits of the first and second edge-emitting semiconductor laser devices by control means (not shown). ing. According to this structure, since the semiconductor lasers having high light emission efficiency are arranged corresponding to the scanning width, it is possible to drive at high speed and form a highly reliable optical scanning device. Further, the data density is high and the data processing is easy, and it becomes possible to cope with the temporal change in the light amount or to perform the intensity modulation. In the above-described embodiment, one photodetector is provided for each edge-emitting semiconductor laser device. However, if feedback is not frequently requested, one photodetector is provided for a plurality of laser devices. You may make it correspond to a photo detector.

The mirror may be formed by processing plastic, glass, an insulating material, or a semiconductor substrate.

Furthermore, the edge emitting semiconductor laser device and the photodetector may be formed separately or may be formed monolithically.

Next, a second embodiment of the present invention will be described. FIG. 3 is a perspective view of a main part of this light source device.

This light source device is capable of irradiating the scanning width L corresponding to the width of the original to be irradiated, etc.
A first edge-emitting semiconductor laser device 12a having a laser array having a plurality of edge-emitting semiconductor lasers on one chip, and a plurality of edge-emitting semiconductors on one chip. Second edge-emitting semiconductor laser devices 12b having a laser array having lasers are arranged in a zigzag pattern, and the first and second mirror surfaces 13a and 13b are arranged in a zigzag pattern so as to correspond to them. A mirror 13 composed of micro prism mirrors arranged in a circle,
It is composed of first and second photodetector arrays 14a and 14b which are respectively arranged outside the first and second edge-emitting semiconductor laser devices with respect to the mirror 13 and detect the optical output of each laser device. The laser light is taken out over a width L in a direction perpendicular to the base substrate.

In this case as well, the outputs of the first and second photodetectors 14a and 14b are control means (not shown).
Is fed back to the drive circuits for the first and second semiconductor laser devices.

As shown in the example of one chip in FIG. 4, 6 electrode wirings are provided on both sides of the chip (direction orthogonal to the laser stripe 17) in both the first and second semiconductor laser element arrays. The present invention is characterized in that a lead wire 19 of a book is formed and a total of 12 bonding pads 18 are arranged at the ends so as to be parallel to the stripe. Here, with a resonator length of 500 μm, a bonding pad area of 80 μm square per laser stripe (including a space for separating pads)
, 6 bonding pads can be arranged in the resonator length direction. For example, if 12 laser stripes are formed with a pitch of 20 μm per chip, the chip width is 20 μm × 12 + 80 μm × 2 = 400 μm.

On the other hand, since the existing area of the stripe is 240 μm and the bonding pad areas at both ends are 80 μm, if the stripe areas of the chips on both sides are installed so as to be continuous, the light emitting points are formed continuously. Become.

It should be noted that the laser stripe portion and the bonding pad portion may be connected to each other by using a lead line by a multi-layer wiring technique in consideration of electrical isolation between the laser stripes, and the pitch of the main scanning line is narrow. Even then, it is possible to easily perform electrode wiring.

According to this structure, it is possible to obtain a highly reliable laser light source device having an extremely high density. Furthermore, in the above-described embodiment, the mirrors are arranged so that the number of spot rows is one, but the number of light spot rows is not limited to one and may be arranged in an arbitrary arrangement. In the case of one column, it becomes possible to facilitate data processing when forming an image on the image carrier. In addition, the scanning density can be dramatically increased, and higher quality image formation can be performed.

Next, a third embodiment of the present invention will be described. This light source device has a base substrate 1 as shown in FIG.
1 is processed by using a dry etching technique, a mirror 13 is integrally formed in advance, and a plurality of semiconductor laser elements 12 each composed of an edge emitting semiconductor laser element array are attached so as to face the mirror 13. is there.
With such a configuration, positioning at the time of attaching the mirror is not necessary, the manufacturing process can be simplified, the device can be downsized, and a highly accurate and highly reliable light source device can be provided. It will be possible.

Next, a fourth embodiment of the present invention will be described. This light source device has a base substrate 11 as shown in FIG.
A semiconductor laser device 12 and a mirror 13 each of which is composed of a plurality of edge-emitting laser arrays each having a resonator are monolithically formed on the upper portion.

In production, cleavage cannot be used to form the Fabry-Perot resonator mirror, so reactive ion beam etching (RIBE) using Cl ₂ plasma or ions using Ar ions and Cl ₂ gas. It is formed by using a beam assist etching (IBAE) method or the like. Further, here, a silicon substrate is used as the base substrate 11, and gallium arsenide (Ga
As) process is used to form a semiconductor laser. In addition,
Although a light source device having a large area can be formed inexpensively by using silicon, silicon is an indirect transition semiconductor and is not suitable for manufacturing a semiconductor laser. Therefore, Ga
As semiconductors are formed on silicon substrates having different lattice constants, and a semiconductor laser is formed by a usual method. A semiconductor laser includes, for example, a lower cladding layer made of n-type aluminum gallium arsenide (AlGaAs) on the surface of a silicon substrate,
A quantum well active layer including a gallium arsenide (GaAs) quantum well layer and an AlGaAs confinement layer, an upper clad layer including p-type AlGaAs, and a p-type GaAs cap layer are sequentially laminated. The elements are separated from each other by the high resistance region 20 by ion implantation such as proton implantation.

According to such a structure, it is possible to provide a small-sized light source device having extremely high accuracy and high reliability.

An optical scanning device using this light source device will be described. As shown in FIG. 7, this device includes a light source device 1, a beam compression optical system 2 including a cylindrical lens that compresses light emitted from the light source device 1 in a sub-scanning direction, a half mirror 3, and the beam compression optical system. From the field lens 4 for controlling the principal ray of the light flux from the system in a predetermined direction, the imaging optical system 5 for condensing the light flux passing through the field lens as a light spot on the surface to be scanned, and the folding mirror 6. The half mirror 3 guides the light flux that is reflected by the imaging optical system 5 and passed through the field lens 4 to the photosensitive drum 7. In the light source device, laser arrays are arranged along the main scanning direction, and the sub scanning direction is the moving direction of the surface to be scanned. Further, the “sub-scanning corresponding direction” means a direction parallel to the sub-scanning direction on a virtual optical path in which the optical path from the light source to the surface to be scanned is linearly expanded along the optical axis. The "main scanning corresponding direction" is also defined in the same manner. The light emitted from the light source device 1 is compressed by the beam compression optical system 2 in the sub-scanning corresponding direction. In the edge-emitting laser, the light emitted from the laser end face has an elliptical shape that is wider in the vertical direction (corresponding to the main scanning direction) than in the horizontal direction (corresponding to the main scanning direction). For the purpose of allowing light to reach well, an image is formed only in the sub-scanning corresponding direction by the cylindrical lens.

The field lens 4 guides the principal ray of the light beam from the beam compression optical system 2 in a predetermined direction, that is, in the direction in which the imaging optical system 5 and the folding mirror 6 are arranged.
Works.

The field lens 4, which is a spherical lens or an aspherical lens, has a length corresponding to the light source device in the main scanning corresponding direction, but is narrowed down by the beam compression optical system 2 in the sub scanning corresponding direction. It has a shape that is cut out leaving a sufficient width for the light flux to enter. The laser beam from the light source device 1 is parallel to the optical axis of the field lens 4, and is collected by the field lens 4 at the image side focal position of this lens.

The image forming optical system 5 and the folding mirror 6 play a role of condensing a light spot on the light emitting point and the surface to be scanned.

According to the optical scanning device having such a structure, it is possible to perform simultaneous writing in the entire scanning width or in an extremely short time by a plurality of laser elements which can be independently driven without a mechanical operating part, and therefore, high speed is achieved. However, it is possible to realize a highly reliable optical scanning device which does not generate noise or heat.

As a method of forming a laser element array or a mirror on the base substrate, a method of individually attaching each element as shown in FIG. 3 or a method of attaching each element as shown in FIG. 5 or FIG. There is a method of integrally forming a part or all of the elements. Although the former requires time and effort for mounting, each element can be manufactured individually, the formation of the device can be efficiently advanced, and the yield is good.

On the other hand, in the latter method, although the process is sophisticated, there is no labor for mounting and it is possible to achieve miniaturization and high accuracy.

[0044]

As described above, according to the present invention, it is possible to improve the scanning density and secure the space for the electrode wiring even when the semiconductor lasers are arranged at a high density. By arranging the mirrors in a zigzag manner, the light spot rows can be arranged in an arbitrary arrangement. For example, by arranging them so as to form the main scanning width in one line, it is possible to simplify data processing when forming an image.

Further, by configuring each of the semiconductor lasers with a laser array, the scanning density can be increased. Further, by arranging a photodetector on the rear end side of the semiconductor laser to control the light amount, it becomes possible to perform high-quality optical scanning recording when used as a light source of a recording device. Therefore, higher density and higher accuracy can be achieved.

Furthermore, by using the optical scanning device of the present invention, it becomes possible to drive a plurality of semiconductor lasers at high density and perform light irradiation over the entire scanning width simultaneously or in an extremely short time, without noise. It enables high-speed scanning with high reliability.

[Brief description of drawings]

FIG. 1 is a perspective view of a light source device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is an explanatory view showing one chip of the device.

FIG. 4 is a diagram showing a light source device according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a light source device according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a light source device according to a third embodiment of the present invention.

FIG. 7 is a diagram showing an optical scanning device using the light source device.

[Explanation of symbols]

 1 Light Source Device 2 Beam Compression Optical System 3 Half Mirror 4 Field Lens 5 Imaging Optical System 6 Folding Mirror 7 Photosensitive Drum 11 Base Substrate 12 Semiconductor Laser Element 12a First Edge-Emitting Semiconductor Laser Element 12b Second Edge-Emitting Type Semiconductor laser device 13 Mirror 13a First mirror surface 13b Second mirror surface 14 Photodetector 14a First photodetector 14b Second photodetector 17 Laser stripe 18 Bonding pad 19 Leading wire

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01S 3/133 3/18 (72) Inventor Mario Fuse 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. Ebina Business In-house (72) Inventor Masao Ito 430 Sakai, Nakai-cho, Ashigarakami-gun, Kanagawa Green Tech Naka Fuji Xerox Co., Ltd.

Claims (7)

[Claims] 1. A tilted mirror type having a plurality of edge-emitting semiconductor laser elements configured to have a horizontal resonance direction and a mirror arranged so as to face the edge-emitting semiconductor laser elements. In the light source device, the edge emitting semiconductor laser devices are arranged on the mounting substrate in a zigzag pattern with the mirrors sandwiched therebetween, and the mirrors are opposed to each other. A light source device using an edge emitting semiconductor laser device, characterized in that it is inclined so that light from a laser device is guided upward and output light is taken out in a direction perpendicular to the mounting substrate. 2. The light source device according to claim 1, wherein each of the edge emitting semiconductor laser elements is composed of a laser array capable of emitting a plurality of laser beams simultaneously or independently. 3. The mirror guides light from a facing laser array upward corresponding to the laser array so that output light is taken out in a line in a direction perpendicular to the mounting substrate. The light source device according to claim 2, wherein the light source devices are arranged in a zigzag pattern and are inclined. 4. The light source device according to claim 1, wherein the plurality of edge emitting semiconductor laser devices and the mirror are monolithically arranged on the same substrate. 5. The plurality of edge-emitting type semiconductor laser elements are provided with a photodetector on the surface opposite to the mirror, and the light amount of the edge-emitting type semiconductor laser elements is determined based on the output of the photodetector. The light source device according to claim 1, further comprising feedback control means for adjusting the light source. 6. The plurality of edge emitting semiconductor laser devices, the mirror and the photodetector are formed on the same substrate,
The light source device according to claim 1, wherein the light source device is arranged monolithically. 7. A mounting board comprising: a plurality of edge-emitting semiconductor laser elements configured to have a horizontal resonance direction; and a mirror arranged to face the edge-emitting semiconductor laser elements. The edge-emitting type semiconductor laser elements are arranged on the upper side in a zigzag pattern with the mirrors sandwiched therebetween, and the light from the edge-emitting type semiconductor laser elements facing the mirror is guided upward to output light. And a beam compression optical system that compresses the light emitted from the light source device in correspondence with the sub-scanning direction, and the beam compression device. A field lens for controlling the principal ray of the light flux from the optical system in a predetermined direction, and an imaging optical system for focusing the light flux passing through the field lens on the surface to be scanned and condensing it. And,
An optical scanning device characterized in that the plurality of semiconductor laser elements are driven simultaneously or independently.