JP2001215436A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner suitable for downsizing. SOLUTION: This optical scanner has an annular semiconductor laser 1 which emits laser beam excited by resonance when receiving a laser beam, a columnar body 11 which is arranged with its outer peripheral surface 12 in a hollow part of the semiconductor laser 1 so as to face the inner peripheral surface 4 of the semiconductor laser 1 and is rotated at a prescribed speed around the central axis and a resonator 13 which is disposed integrally at the columnar body 11 and is arranged with a reflection end face 14 for reflecting the laser beam from the semiconductor laser 1 and making the laser beam incident on the inner peripheral surface 4 of the semiconductor laser 1 at the outer peripheral surface 12 of the columnar body 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device used for a laser printer, a facsimile, a digital copier, and the like.

[0002]

2. Description of the Related Art Conventionally, an optical scanning device has been used as a writing optical system of an electrophotographic image forming apparatus such as a laser printer, a facsimile, and a digital copying machine. As this type of optical scanning device, there is known an optical scanning device described in Japanese Utility Model Laid-Open No. 2-21620. As shown in FIG. 4, the conventional optical scanning device includes a rotating disk 101 provided apart from a surface to be scanned and rotating around an axis at a predetermined speed.
A semiconductor laser 10 fixed on the rotating disk 101 and serving as a laser light source for irradiating the scanning surface with laser light.
And 2. In this conventional optical scanning device,
By rotating the rotating disk 101, the rotating disk 10
The laser beam is scanned by rotating a semiconductor laser 102 mounted on the laser beam.

[0003]

However, in the conventional optical scanning device, a rotating disk 101 for rotating a semiconductor laser (laser light source) 102 is required to scan a laser beam. There is a problem that it is not suitable for miniaturization because it is large. An object of the present invention is to provide an optical scanning device which does not require a large rotating disk for rotating a laser light source and is suitable for downsizing.

[0004]

In order to solve the above-mentioned problems, the present invention according to claim 1 provides a ring-shaped semiconductor laser that emits excited laser light when receiving laser light. A cylindrical body which is arranged in a hollow portion of the semiconductor laser such that an outer peripheral surface thereof faces the inner peripheral surface of the semiconductor laser and is rotated at a predetermined speed about a central axis; And a resonator disposed on the outer peripheral surface of the cylindrical body to have a reflection end face for reflecting laser light from a laser and entering the inner peripheral surface of the semiconductor laser. According to a second aspect of the present invention, there is provided a substrate, a first cladding layer formed on the substrate, an active layer formed on the first cladding layer, and a first cladding layer formed on the active layer. A ring-shaped semiconductor laser having two cladding layers, voltage applying means for applying a voltage to the first and second cladding layers of the semiconductor laser to flow a current through the active layer, and a hollow portion of the semiconductor laser. A cylindrical body disposed so that an outer peripheral surface thereof faces the inner peripheral surface of the semiconductor laser, and rotated at a predetermined speed around a central axis; and the active layer of the semiconductor laser integrally disposed on the cylindrical body. And a resonator disposed on the outer peripheral surface of the cylindrical body to have a reflection end face for reflecting the laser light from the semiconductor laser and entering the active layer of the semiconductor laser.

[0005]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a main part of an optical scanning device as one embodiment of the present invention,
FIG. 2 is a cross-sectional view showing the semiconductor laser, the cylindrical body, and the resonator of the optical scanning device of FIG. 1 along the line XX. As shown in FIG. 1, a ring-shaped semiconductor laser 1
Is fixed on the heat sink 2. As shown in FIGS. 1 and 2, the semiconductor laser 1 has an outer peripheral surface 3 that is a circumferential surface and an inner peripheral surface 4 that is a circumferential surface. That is, the semiconductor laser 1 has an outer peripheral surface 3 and an inner peripheral surface 4 that are emission surfaces. A semiconductor laser 1 is fixed on a heat sink 2 and is made of a substrate 5 made of GaAs or the like.
And a cladding layer 6 formed on the substrate 5, an active layer 7 formed on the cladding layer 6, and a cladding layer 8 formed on the active layer 7. . That is, the semiconductor laser 1 has a structure in which an active layer 7 is sandwiched between two cladding layers 6 and 8 on a substrate 5. A lead wire 9 is connected to the cladding layer 6. Also,
A lead wire 10 is connected to the cladding layer 8. These cladding layers 6 and 8 are connected to a voltage applying device (not shown) by leads 9 and 10. This voltage application device causes a laser beam to be emitted from the active layer 7 by applying a predetermined voltage to the cladding layers 6 and 8 and causing a current to flow through the active layer 7. In this case, the laser light emitted from the active layer 7 is weak because it is not excited by resonance, and cannot be used as scanning light because of its low energy. The voltage application device can change the current flowing through the active layer 7 by changing the voltage applied to the cladding layers 6 and 8 according to the image data. Therefore, the voltage applying device can easily and accurately modulate the laser light according to the image data.

In the hollow portion of the semiconductor laser 1, a cylindrical body 1 is provided.
1 is arranged so that the outer peripheral surface 12 faces the inner peripheral surface 4 of the semiconductor laser 1. For example, the cylindrical body 11 has an outer peripheral surface 12 and an inner peripheral surface 4
They are arranged to have an interval of micrometers. The cylindrical body 11 is rotated around the central axis at a predetermined speed by a driving device (not shown). This drive is
It is composed of a driving device using electrostatic force or a driving device using electromagnetic force. A resonator 13 is provided integrally with the cylindrical body 11. Reflection end face 14 of resonator 13
Has a predetermined area, and has a peripheral surface obtained by extending the outer peripheral surface 12 of the columnar body 11. The reflection end face 14 of the resonator 13 is
The laser light from the active layer 7 of the semiconductor laser 1 is reflected and made incident on the active layer 7 of the semiconductor laser 1. That is, the voltage applying device applies a predetermined voltage to the cladding layers 6 and 8.
The cavity 13 reflects the weak laser light from the active layer 7 of the semiconductor laser 1 in a state where the weak laser light is emitted from the active layer 7 by applying a current to the active layer 7 to apply a current to the semiconductor laser. The light is incident on the first active layer 7. At this time, the reflection end face 14 of the resonator 13 has a predetermined area, and the active layer 7 is excited by the laser light of only the excitation portion 15 that receives the weak laser light reflected from the reflection end face 14 of the resonator 13. Accordingly, the excited strong laser beam is emitted from the outer peripheral surface of the semiconductor laser 1 in the direction of arrow A. Further, since the reflection end face 14 of the resonator 13 moves with the rotation of the cylindrical body 11, the excitation portion 15 of the semiconductor laser 1 that receives the laser light reflected from the reflection end face 14 of the resonator 13 also moves. Scanned. Thus, in the optical scanning device of the present invention,
By rotating the cylindrical body 11 disposed in the hollow portion of the ring-shaped semiconductor laser 1, the resonator 13 is rotated, and the laser light reflected on the reflection end face 14 of the resonator 13 is rotated to rotate the semiconductor laser 1. Since the laser beam is scanned by rotating the excitation portion 15 of the semiconductor laser 1 by being incident on the inner peripheral surface, a large rotating disk for rotating the laser light source is not required. Is suitable for

FIG. 3 is a schematic plan view showing a main part of an optical scanning device according to an embodiment of the present invention. As shown in FIG. A scanning surface 17 is arranged at a predetermined distance from the light-collecting optical system 16. The condensing optical system 16 condenses a bundle of laser light, which is light emitted from the semiconductor laser 1, on the surface to be scanned 17. It should be noted that the semiconductor laser is not limited to the illustrated embodiment, but may be any laser that emits the excited laser light upon receiving the laser light. The present invention can be applied not only to a writing optical system of an electrophotographic image forming apparatus such as a printer, a digital copying machine, and a facsimile apparatus, but also to any apparatus using an optical scanning device.

[0008]

As described above, according to the first aspect of the present invention, the resonator is rotated by rotating the cylindrical body disposed in the hollow portion of the ring-shaped semiconductor laser, and the light is reflected by the reflection end face of the resonator. Since the laser beam is rotated and the laser beam is scanned by rotating the excitation portion of the semiconductor laser by entering the semiconductor laser, a large rotating disk on which the laser light source is mounted is unnecessary, so that Is suitable for According to a second aspect of the present invention, in the first aspect of the present invention, the semiconductor laser includes a substrate, a first cladding layer formed on the substrate, an active layer formed on the first cladding layer, A second cladding layer formed on the active layer, wherein voltage applying means applies a voltage to the first and second cladding layers to flow a current through the active layer; Since the current flowing through the active layer can be changed by changing the voltage applied according to the image data, a large rotating disk for rotating the laser light source is unnecessary, so that it is suitable for miniaturization, and
Easy modulation of laser light according to image data, and
Can be done accurately.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of an optical scanning device as one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a semiconductor laser, a columnar body, and a resonator of the optical scanning device of FIG. 1 along a line XX.

FIG. 3 is a schematic plan view showing a main part of an optical scanning device as one embodiment of the present invention.

FIG. 4 is a plan view showing a main part of a conventional optical scanning device.

[Explanation of symbols]

1 semiconductor laser, 2 heat sink, 3 outer peripheral surface,
4 inner peripheral surface, 5 substrate, 6 cladding layer, 7 active layer,
8 cladding layer, 9 lead wire, 10 lead wire, 11
Cylindrical body, 12 outer peripheral surface, 13 resonator, 14 reflection end face, 15 excitation part, 16 light-collecting optical system, 17 scanned surface.

Claims (2)

[Claims] 1. A ring-shaped semiconductor laser that emits a laser beam excited by resonance when receiving a laser beam, and a hollow portion of the semiconductor laser having an outer peripheral surface facing an inner peripheral surface of the semiconductor laser. A cylindrical body that is arranged and rotated at a predetermined speed about a central axis, and a reflection that is disposed integrally with the cylindrical body and reflects laser light from the semiconductor laser to be incident on the inner peripheral surface of the semiconductor laser. An optical scanner having an end face disposed on an outer peripheral surface of the cylindrical body. 2. A substrate, a first cladding layer formed on the substrate, an active layer formed on the first cladding layer, and a second cladding layer formed on the active layer. A semiconductor laser having a ring shape, a voltage applying means for applying a voltage to the first and second cladding layers of the semiconductor laser to cause a current to flow through the active layer, and an outer peripheral surface formed in a hollow portion of the semiconductor laser. A cylindrical body that is arranged to face the inner peripheral surface of the semiconductor laser and that is rotated at a predetermined speed about a central axis; and a laser beam from the active layer of the semiconductor laser that is integrally provided with the cylindrical body and is integrated with the cylindrical body. An optical scanning device, comprising: a resonator disposed on an outer peripheral surface of the columnar body so as to have a reflection end face for reflecting light to enter the active layer of the semiconductor laser.