JP2908652B2 - Light scanning light source device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning light source device used for optical scanning writing in a laser printer, a digital copying machine, or the like.

[0002]

2. Description of the Related Art In recent years, laser technology has been widely used in various fields, and as one of them, a laser light source such as a semiconductor laser has been used for optical writing for image recording. I have. FIG. 6 shows such a semiconductor laser 1
In this figure, a laser chip (light source) 2 as a main component and a photodiode 3 for receiving a back beam thereof as detection light are integrally mounted.

[0003] Since the output of the semiconductor laser generally has such a temperature characteristic as shown in FIG. 7, the detection output of the photodiode 3 is provided as shown in FIG. This is to make the semiconductor laser control board 6 perform feedback correction through the main output setting circuit 5 to stabilize the semiconductor laser output irrespective of the temperature change.

In this type of optical scanning apparatus, for example, optical writing for a plurality of lines is simultaneously performed by one light source,
Recently, for the purpose of further increasing the speed, a semiconductor laser having a plurality of light emitting sources is used, and each light emitting source is individually controlled to emit light.

[0005]

In the case of such a semiconductor laser having a plurality of light emitting points, a temperature change causes
Since the output fluctuates, feedback correction means for the output is required. However, in a semiconductor laser, it is difficult to individually detect a back beam corresponding to each light emitting source with one photodiode as shown in FIG. 6 due to the circuit configuration, and a stable output cannot be obtained. It has become.

[0006]

According to the first aspect of the present invention, there is provided an optical scanning apparatus for performing optical writing using a light beam emitted from a semiconductor laser having a plurality of light emitting sources whose light emission is individually controlled. In the light source device, a half mirror that separates a part of a light beam emitted from the semiconductor laser and a light receiving unit that receives a detection light beam that is separated and reflected by the half mirror are disposed on a base member that supports the semiconductor laser. It was integrated and mounted.

In this case, according to the second aspect of the invention, the light receiving portion is a light receiving surface of an optical sensor.
The light receiving portion was used as an inlet for an optical fiber for guiding the detection light beam to the light receiving element, and a holding portion for holding the inlet for the optical fiber was formed in the base member.

According to the present invention, the detection light beam separated and reflected by the half mirror is focused on the light receiving portion at a position where the light emitting source of the semiconductor laser and the light receiving portion are in an optically conjugate relationship. In a fifth aspect of the present invention, the detection light flux separated and reflected by the half mirror is placed on the light receiving unit at a position where an optical conjugate relationship is established between the light emitting source of the semiconductor laser and the light receiving unit. A concave mirror for focusing is provided.

According to the present invention, the optical axis of the detection light beam incident on the light receiving portion is set to be inclined with respect to the normal line of the light receiving portion.

Further, in the invention according to claim 7, the circuit board on which the optical sensor is mounted and on which a part of the drive circuit for the semiconductor laser is formed is integrated with the base member.

[0011]

According to the first and second aspects of the present invention, a part of a light beam emitted from a semiconductor laser having a plurality of light emitting sources is separated and reflected by a half mirror, and is guided as a detection light beam to a light receiving portion such as an optical sensor. Since it is used for output control, it is possible to obtain a stable light output in the multiple light source type,
At this time, since the half mirror and the light receiving section are integrally mounted on the base member for the semiconductor laser, the light output can be detected even when adjusting the position with the collimator lens, and eventually, the conventional single unit is used. The light source device can be handled in the same manner as a single light source type light source device.

The same effect is obtained in the case of the third aspect of the invention. In particular, since the light receiving portion is integrated with the base member by the holding portion as an optical fiber introduction port, the circuit board is integrated with the base member. If you ca n’t,
The detection light beam is optically transmitted to the light receiving element without being affected by external noise or the like, and reliable detection is possible.

According to the fourth and fifth aspects of the present invention, the detection light beam can be detected efficiently by setting the light emitting source and the light receiving portion at an optically conjugate relationship position using a condenser lens or a concave mirror. In addition, the influence of the arrangement error of the optical element and the deviation of the optical path due to the environmental change can be avoided as much as possible. In particular, in the case of using a concave mirror, the number of parts can be reduced.

In the present invention, the optical axis of the detection light beam incident on the light receiving portion is set to be inclined with respect to the normal line of the light receiving portion, so that the return light from the light receiving portion affects the semiconductor laser output. Can be removed, and stable output control can be performed.

In the invention according to claim 7, the circuit board on which a part of the drive circuit is formed is integrated with the base member,
Since a circuit is configured by mounting not only a semiconductor laser but also an optical sensor, the influence of external noise is reduced, and highly reliable light detection is possible.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. First, a drive circuit corresponding to the output detection unit, the output setting circuit, the semiconductor laser control board, and the like shown in FIG. 8 is formed, and a PC board (circuit board) 12 to which the semiconductor laser 11 is mounted and connected is provided. . The semiconductor laser 11 has a plurality of light sources (not shown) whose light emission is individually controlled.
And a base member 13 having a press-fit portion 13a to which the light-emitting side head is press-fitted and fixed is provided. The base member 13 is provided with the engaging hole 12 of the PC board 12.
a, which has a mounting leg 13b to be engaged with a. Here, the upper part of the press-fitting portion 13a is open, and the writing light flux 14 emitted from the plurality of light emitting sources of the semiconductor laser 11 is formed so as to advance to the collimator lens side as described later. Such a writing light beam 14 is positioned on the optical axis min in a direction perpendicular to a part as the detection light flux 15
A half mirror 16 for separating and reflecting light is provided. A reflection mirror 17 is provided to bend the detection light beam 15 separated and reflected by the half mirror 16 toward the PC board 12 in an L-shape. An optical sensor serving as a light receiving unit is provided at a corresponding position on the PC board 12. 18 is mounted, and an optical sensor mounting recess 13c is formed on the base member 13 side. Thus, not only the semiconductor laser 11 but also the optical sensor 18 and the PC board 12 are integrated with the base member 13.

Further, a condenser lens 19 is provided on the optical path between the mirrors 16 and 17. The condenser lens 19 condenses the light beam 15 detected by the half mirror 16 on the light receiving surface of the optical sensor 18. The light emitting point of each light emitting source of the semiconductor laser 11 and the light receiving surface of the optical sensor 18 are optically coupled. The arrangement is set so as to form a spatially conjugate relationship.

Here, the optical axis of the detection light beam 15 with respect to the optical sensor 18 is set to be inclined at a slight angle θ with respect to the normal to the light receiving surface of the optical sensor 18.

Attachment portions 13d, 13e, 1 for attaching the half mirror 16, the condenser lens 19 and the reflection mirror 17 to the base member 13 at predetermined positions and angles.
3f is formed in the recess wall, and is locked by a leaf spring 20 having legs for pressing each part. This leaf spring 20 is fixed by its locking portion 20a locking to a projection 13g on the side surface of the base member 13.

Further, such a base member 13 is adjusted and fixed to a flange 22 on which a collimator lens 21 is mounted, thereby forming a light source device for emitting a parallel light beam.

According to such a configuration, the writing beam 14 which is the front beam of the semiconductor laser 11 having a plurality of light emitting sources is used, and a part thereof is
6 The separated reflected detect light output by input to the optical sensor 18, so subjected to feedback control, it shall be detected without hindrance by the light emitting sources of the light output of one of the optical sensors 18, the temperature change Light output can be obtained stably. In particular, the semiconductor laser 11, the half mirror 16, and the optical sensor 18, which are optical members for this purpose, are integrated by the base member 13 and are positioned relative to each other. Even so, the light output of the semiconductor laser 11 can be detected and can be handled in the same manner as a conventional single light source type light source device. Further, in addition to the semiconductor laser 11, a drive circuit is formed, and the PC board 12 on which the optical sensor 18 is mounted is also integrated with the base member 13.
Only the plate 12 is required, and the effect of external noise can be reduced as much as possible. Further, a condenser lens 19 for condensing the detection light beam 15 on the light receiving surface of the optical sensor 18 is provided.
Since the light receiving surfaces are set to have an optical conjugate relationship, the light output can be detected efficiently. That is, the arrangement error due to the press-fitting of the semiconductor laser 11 into the base member 13 and the arrangement error of other optical elements, and the influence of the optical path shift due to the environmental change are minimized. Furthermore,
Since the optical axis of the detection light beam 15 with respect to the light receiving surface of the optical sensor 18 is set to be inclined, the return light from the optical sensor 18 does not return to the semiconductor laser 11 side, and the output of the semiconductor laser 11 is unstable due to the return light. Can be suppressed.

Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as the parts shown in the above-mentioned embodiment are denoted by the same reference numerals (the same applies to the following embodiments).
In the present embodiment, a concave mirror 23 having a condensing function is provided instead of the condensing lens 19 and the reflecting mirror 17. That is, the concave mirror 23 focuses the detection light beam 15 separated and reflected by the half mirror 16 on the light receiving surface of the optical sensor 18, and is set so that the light emitting point and the light receiving surface have an optical conjugate relationship. ing.

Therefore, in the case of the present embodiment, the same effect as in the case of the above embodiment can be obtained.
The function of the reflection mirror 17 is one optical member (the concave mirror 2).
3) is sufficient, and the number of parts can be reduced.

In this embodiment, the concave mirror 23 is also used.
May be set so that its optical axis has an inclination with respect to the normal to the light receiving surface of the optical sensor 18.

Further, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, instead of the optical sensor 18, an inlet 24a of the optical fiber 24 is provided as a light receiving section, and the detection light beam 15 is transmitted by the optical fiber 24 and guided to a light receiving element (not shown). It is. Here, a holding claw (holding portion) 13 h for holding the plug portion 25 at the end of the optical fiber 24 to the base member 13 is attached to the base member 1.
3 are formed integrally.

According to this embodiment, the same effects as those of the above-described embodiment can be obtained, but it is particularly effective when the PC board 12 cannot be integrated with the base member 13. That is, in such a case, the light is
When the circuit is guided to the circuit on the C board 12, the lead wire portion between the sensor and the PC board is affected by external noise. However, since the optical transmission by the optical fiber 24 is performed, the lead is strong against external noise.

[0027]

According to the first and second aspects of the present invention, a part of a light beam emitted from a semiconductor laser having a plurality of light emitting sources is separated and reflected by a half mirror, and is used as a detection light beam as a detection light beam. Guide to the light receiving part such as the entrance of the optical fiber,
Since the optical output is detected and used for output control, a stable optical output can be obtained in the case of the multiple light source type, and at this time, these half mirrors and light receiving sections are integrated with the base member for the semiconductor laser. The light source can be detected even at the time of position adjustment with the collimator lens and the like, so that the light source device can be handled in the same manner as the conventional single light source type light source device. In particular, claim 3
In the case of the invention described, since the light receiving portion is integrated with the base member by the holding portion as an optical fiber introduction port, when the circuit board cannot be integrated with the base member, it may be affected by external noise and the like. Thus, the detection light beam is transmitted optically to the light receiving element, and the detection can be reliably performed.

According to the fourth and fifth aspects of the present invention,
Since the light-emitting source and the light-receiving unit are set in an optically conjugate relationship using a condensing lens or concave mirror that focuses the detection light beam on the light-receiving unit, the detection light beam can be detected efficiently and the optical Influences such as an optical path shift due to an element arrangement error and an environmental change can be avoided as much as possible. In particular, when a concave mirror is used, the number of parts can be reduced.

According to the sixth aspect of the present invention, the optical axis of the detection light beam incident on the light receiving portion is set to be inclined with respect to the normal line of the light receiving portion, so that the return light from the light receiving portion to the semiconductor laser output. The influence can be removed and stable output control can be performed.

According to the seventh aspect of the present invention, the circuit board on which a part of the drive circuit is formed is integrated with the base member, and not only the semiconductor laser but also the optical sensor is mounted on the circuit board. The influence is small, and highly reliable light detection becomes possible.

[Brief description of the drawings]

FIG. 1 is a sectional structural view showing a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a part thereof.

FIG. 3 is a sectional structural view showing the vicinity of a light receiving unit.

FIG. 4 is a sectional structural view showing a second embodiment of the present invention.

FIG. 5 is a sectional structural view showing a third embodiment of the present invention.

FIG. 6 is a partially cutaway perspective view of a general semiconductor laser showing a conventional example.

FIG. 7 is a temperature-output characteristic diagram of a semiconductor laser.

FIG. 8 is a block diagram showing the feedback control system.

[Explanation of symbols]

 Reference Signs List 11 semiconductor laser 12 circuit board 13 base member 13h holding unit 15 detection light beam 16 half mirror 18 optical sensor (light receiving unit) 19 condensing lens 23 concave mirror 24 optical fiber 24a inlet

Claims (7)

(57) [Claims] 1. An optical scanning light source device in which optical writing is performed using a light beam emitted from a semiconductor laser having a plurality of light emitting sources whose light emission is individually controlled, the light beam emitted from the semiconductor laser. Optical scanning, wherein a half mirror for separating a part of the semiconductor laser and a light receiving unit for receiving a detection light beam separated and reflected by the half mirror are integrally mounted on a base member supporting the semiconductor laser. Light source device. 2. The light source device for optical scanning according to claim 1, wherein the light receiving section is a light receiving surface of an optical sensor. 3. The light receiving device according to claim 1, wherein the light receiving portion is an inlet of an optical fiber for guiding the detection light beam to the light receiving element, and a holding portion for holding the inlet of the optical fiber is formed on the base member. Light scanning light source device. 4. A semiconductor laser focused to condensing the detection light fluxes separated reaction <br/> Isa by the half mirror on the light receiving unit at a position that forms an optical conjugate relationship between the light-emitting source and the light receiving portion of the The light source device for optical scanning according to claim 1, further comprising a lens. Wherein the concave mirror focusing the detection light fluxes Isa separated reaction <br/> by the half mirror at a position which forms an optically conjugate relationship between the light emitting sources of the semiconductor laser and the light receiving unit on the light receiving portion The light source device for optical scanning according to claim 1, 2, or 3, further comprising: 6. The light source for optical scanning according to claim 1, wherein an optical axis of a detection light beam incident on the light receiving portion is set to be inclined with respect to a normal line of the light receiving portion. apparatus. 7. A circuit board on which an optical sensor is mounted and a part of a driving circuit for a semiconductor laser is formed is integrated with a base member.
7. The light source device for optical scanning according to 4, 5, or 6.