JP3821618B2 - Multi-beam scanning light source device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multi-beam scanning light source device, and more particularly to a multi-beam scanning light source device applicable to an LBP, a digital copying machine, a PPF, and the like.
[0002]
[Prior art]
In recent years, there has been an increasing demand for higher speed optical scanning devices. In order to meet this requirement, in the case of a one-beam scanning optical scanning device, the rotational speed of the deflector must be very high, which requires noise reduction and high light source output. The cost will be high. On the other hand, in the case of the multiple beam scanning method, since a plurality of light beams are scanned at a pitch interval in the sub-scanning direction on the surface to be scanned, high-speed printing is possible without increasing the rotational speed of the deflector.
[0003]
Some conventional multi-beam scanning optical scanning devices combine a plurality of beams using a λ / 2 plate and a polarization combining element and simultaneously scan two light beams. Is expensive, and needs to be arranged with high accuracy, so it is very difficult to reduce the cost of this optical scanning device.
[0004]
[Problems to be solved by the invention]
In view of this, there is a type in which a plurality of light sources are separated from each other in the main scanning direction, and a plurality of light beams emitted toward the deflector have an opening angle, thereby performing optical scanning with a plurality of beams without using a polarization combining element. Although this optical scanning device can be made at a lower cost than an optical scanning device using a polarization beam combining element, conventionally, a lens cell or the like is used to fix the coupling lens. Therefore, there is a problem that the distance cannot be reduced.
[0005]
The present invention has been made to solve the above-described problems of the prior art, and by bonding and fixing the coupling lens to the holder, the distance between the coupling lenses can be reduced and the layout can be reduced. An object of the present invention is to provide a multi-beam scanning light source device capable of performing the above.
The present invention also provides a multi-beam scanning light source device capable of improving the optical characteristics by suppressing fluctuations in the beam pitch in the sub-scanning direction due to environmental fluctuations such as temperature rise with a simple configuration at low cost. The purpose is to provide.
[0006]
[Means for Solving the Problems]
The invention described in claim 1 includes a plurality of light sources, a coupling lens system for coupling divergent light beams from the plurality of light sources, a deflector for deflecting light beams that have passed through the coupling lens system at an equal angular velocity, A scanning optical system that focuses a plurality of light beams deflected by the deflector toward a surface to be scanned and scans the surface to be scanned at a substantially constant speed, and includes at least two light sources among the plurality of light sources. In the optical system in which the light beam emitted from and passing through the coupling lens toward the deflector has an opening angle, each of the light sources is a semiconductor laser, and the semiconductor laser chip and the stem holding the semiconductor laser chip are in the main scanning direction. They are arranged in the same direction.
[0007]
According to a second aspect of the present invention, in the first aspect of the present invention, the portion connected to the electrical system that drives each semiconductor laser is constituted by a harness substrate, and the ground of the harness substrate is common to the ground of each semiconductor laser. It is characterized by connecting.
[0008]
According to a third aspect of the present invention, in the second aspect of the present invention, the conductor portion on the harness substrate that connects the pins other than the grounds of the two semiconductor lasers has the same resistance and capacitance as the pins having the same function of each semiconductor. It is characterized by being equivalent.
[0009]
According to a fourth aspect of the present invention, in the first aspect of the present invention, the semiconductor laser chip is arranged such that the direction in which the divergence angle is large is substantially parallel to the main scanning plane.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a multi-beam scanning light source device according to the present invention will be described below with reference to the drawings. As shown in FIG. 6, reference numerals 1 and 2 indicate two light sources arranged in the main scanning direction among a plurality of light sources applicable to the present invention. The light sources 1 and 2 are constituted by semiconductor lasers. Coupling lens systems 3 for coupling divergent light beams emitted from the light sources 1 and 2 are provided on the emission sides of the light sources 1 and 2, respectively. The coupling lens system 3 includes a coupling lens 3a that converts the divergent light beams emitted from the light sources 1 and 2 into a convergent light beam, a divergent light beam, or a parallel light beam, and an aperture that shapes the light beam transmitted through the coupling lens 3a. 3b.
[0011]
As shown in FIG. 6, this optical system is an optical system in which each light beam emitted from the light sources 1 and 2 and passing through the coupling lens 3a and going to the rotary polygon mirror 5 as a deflector has an opening angle. . Accordingly, the light beams emitted from the light sources 1 and 2 and passed through the coupling lens systems 3 are transmitted through the cylinder lens 4 and are condensed to each other in the vicinity of the polarization reflection surface of the rotary polygon mirror 5, so that the rotary polygon mirror 5 is deflected at a constant angular velocity.
[0012]
Reference numeral 6 denotes a scanning lens as a scanning optical system. The scanning lens 6 focuses a plurality of light beams deflected by the rotary polygon mirror 5 toward the scanned surface 7 and scans the scanned surface 6 at a substantially constant speed. Accordingly, the plurality of light beams deflected by the rotary polygon mirror 5 pass through the scanning lens 6 to scan the surface to be scanned 7 at a substantially constant speed.
[0013]
Next, features of the present invention will be described. In FIG. 1, the emission side front view of the said light sources 1 and 2 is shown. The light source 1 is composed of a semiconductor laser mainly composed of a semiconductor laser chip 1a, a stem 1b, and a holder 1c. A stem 1b is fixed to the holder 1c, and a semiconductor laser chip 1a is held on the stem 1b. Similarly, the light source 2 is composed of a semiconductor laser mainly composed of a semiconductor laser chip 2a, a stem 2b, and a holder 2c. The stem 2b is fixed to the holder 2c, and the semiconductor laser is attached to the stem 2b. The chip 2a is held. As shown in FIG. 7, the semiconductor laser chip 1a and the semiconductor laser chip 2a are arranged so that the one with the larger divergence angle is substantially parallel to the main scanning plane.
[0014]
As described above, the light sources 1 and 2 are provided side by side in the main scanning direction, and the stem 1b of the light source 1 and the stem 2b of the light source 2 are arranged in the same direction in the main scanning direction, and are on the stem 1b. The semiconductor laser chip 1a is held, and the semiconductor laser chip 2a is held on the stem 2b. That is, the semiconductor laser chip 1a and the semiconductor laser chip 2a, and the stem 1b and the stem 2b are arranged in the same direction in the main scanning direction. Note that the stems 1b and 2b shown in FIG. 1 are arranged to the right in the main scanning direction.
[0015]
As shown in FIG. 4, the light sources 1 and 2 are held by an optical holder 8. The optical holder 8 has two holes 11 and 12 arranged in the main scanning direction, and a protrusion 13 extending in the optical axis direction is formed at the center between the holes 11 and 12. This protrusion 13 is formed so as to become thinner toward the tip side. The light source 1 is mounted in the hole 11 along the outer periphery of the protrusion 13, and the light source 2 is mounted in the hole 12 along the outer periphery of the protrusion 13. As described above, the semiconductor laser chip 1 a and the semiconductor laser chip are mounted. 2a, and the stem 1b and the stem 2b are arranged in the same direction in the main scanning direction, and the semiconductor laser chip 1a and the semiconductor laser chip 2a are arranged in the main scanning direction as shown in FIG. It arrange | positions so that it may become substantially parallel to a plane. Note that the light beams emitted from the light sources 1 and 2 form an opening angle due to the inclination of the protrusion 13.
[0016]
Further, as shown in FIGS. 3 and 4, the two coupling lenses 3 a and 3 a are positioned on the outer periphery in the vicinity of the tip of the protruding portion 13 so that the light beams of the light source 1 and the light source 2 can pass through. Each is fixed by an adhesive 14. The two coupling lenses 3a and 3a are fixed to the outer periphery in the vicinity of the distal end portion of the protruding portion 13 by the adhesive 14 after the position is adjusted with high accuracy in the three axial directions.
[0017]
Each semiconductor laser of the light sources 1 and 2 is driven by an electrical system (not shown). As shown in FIG. 5, in each of the semiconductor lasers of the light sources 1 and 2, a portion connected to the electrical system is constituted by a harness substrate 22. On the harness board | substrate 22, the some conducting wire part 17, 18, 19, 20, 21 is formed in order from the left side.
[0018]
The conducting wire portion 19 formed at the center on the harness substrate 22 is formed in a symmetrical T-shape on the left and right, and forms the ground of the harness substrate 22. The ground pin 15 (see FIG. 2) of the semiconductor laser of the light source 1 is connected to the left side of the umbrella part of the conductor 19 and the ground pin 16 of the semiconductor laser of the light source 2 is connected to the right of the umbrella of the conductor 19. (See FIG. 2) are connected. That is, the ground of the harness substrate 22 is commonly connected to the grounds of the semiconductor lasers of the light sources 1 and 2.
[0019]
By doing so, the layout of the conductor portion on the harness substrate 22 can be simplified, and the conductor portion 19 forming the ground of the harness substrate 22 is formed in a symmetrical T-shape. Therefore, it is possible to equalize stress against fluctuations in the semiconductor lasers of the light sources 1 and 2 due to environmental fluctuations such as a temperature rise, and to change the beam pitch in the sub-scanning direction due to environmental fluctuations such as a temperature rise. It is possible to suppress and improve the optical characteristics.
[0020]
Further, the drive pin 23 (see FIG. 2) of the semiconductor laser of the light source 1 is connected to the lead wire portion 17 of the harness substrate 22, and the lead wire portion 18 has functions other than the driving of the semiconductor laser of the light source 1 and the ground. A pin 24 (see FIG. 2) with Further, a drive pin 25 (see FIG. 2) of the semiconductor laser of the light source 2 is connected to the lead wire portion 21 of the harness substrate 22, and the lead wire portion 20 has functions other than the driving of the semiconductor laser of the light source 2 and the ground. A pin 26 (see FIG. 2) with The conducting wire portions 17, 18, 20, and 21 have the same resistance and electric capacity as those of the pins having the same functions of the semiconductors of the light sources 1 and 2. That is, the lead wire portion 17 and the lead wire portion 21 have the same resistance and capacitance, and the lead wire portion 18 and the lead wire portion 20 have the same resistance and capacitance.
[0021]
As described in the section of the problem to be solved by the invention, since the lens cell or the like is conventionally used to fix the coupling lens, the distance between the coupling lenses becomes large, and therefore, the layout. However, according to the above embodiment, since the coupling lens 3a is bonded and fixed to the optical holder 8, the distance between the coupling lenses is reduced, thereby reducing the layout. be able to.
[0022]
Further, since the semiconductor laser chip 1a and the semiconductor laser chip 2a, and the stem 1b and the stem 2b are arranged in the same direction in the main scanning direction, the semiconductor laser chip 1a and the semiconductor laser chip 2a are caused by environmental fluctuations such as a temperature rise. Even if a positional deviation occurs between the stem 1b and the stem 2b, this positional deviation can be made to be a positional deviation in the same direction. The optical characteristics can be improved by suppressing the variation of the beam pitch, and the assembling workability can be improved.
[0023]
Each of the semiconductor lasers of the light sources 1 and 2 includes a harness substrate 22 that is connected to the electrical system, and the ground of the harness substrate 22 is common to the grounds of the semiconductor lasers of the light sources 1 and 2. As a result of the connection, stress can be equalized against fluctuations in the semiconductor lasers of the light sources 1 and 2 due to environmental fluctuations such as temperature rise, and the beam pitch in the sub-scanning direction due to environmental fluctuations such as temperature rise The optical characteristics can be improved by suppressing the fluctuation.
[0024]
Further, the conductor portions 17, 18, 21, and 20 on the harness substrate 22 to which the pins 23, 24, 25, and 26 other than the grounds of the respective semiconductor lasers of the light sources 1 and 2 are connected to each other in terms of resistance and electric capacity. Are equivalent to the same pin, the light emission characteristics of each semiconductor can be improved.
[0025]
Further, since the semiconductor laser chip 1a and the semiconductor laser chip 2a are arranged so that the direction in which the divergence angle is large is substantially parallel to the main scanning plane, the fluctuation of the beam pitch in the sub-scanning direction due to environmental fluctuations such as a temperature rise. It is possible to suppress and improve the optical characteristics.
[0026]
【The invention's effect】
According to the first aspect of the present invention, a plurality of light sources, a coupling lens system for coupling divergent light beams from the plurality of light sources, and a deflector for deflecting light beams that have passed through the coupling lens system at an equiangular velocity. And a scanning optical system that focuses a plurality of light beams deflected by the deflector toward the surface to be scanned and scans the surface to be scanned at a substantially constant speed, and includes at least two of the plurality of light sources. In an optical system in which a light beam emitted from one light source, passing through a coupling lens, and directed toward the deflector has an opening angle, each light source is a semiconductor laser, and a semiconductor laser chip and a stem holding the semiconductor laser chip perform main scanning. Are arranged in the same direction, so that the optical characteristics can be improved with a simple configuration by suppressing fluctuations in the beam pitch in the sub-scanning direction due to environmental fluctuations such as temperature rise. It is, it is possible to improve the assembling workability.
[0027]
According to the invention described in claim 2, in the invention described in claim 1, the portion connected to the electrical system that drives each semiconductor laser is constituted by the harness substrate, and the ground of the harness substrate is connected to the ground of each semiconductor laser. Since it is connected in common, it is possible to equalize stress against fluctuations in each semiconductor laser of the light source due to environmental fluctuations such as temperature rises, and to suppress fluctuations in the beam pitch in the sub-scanning direction due to environmental fluctuations such as temperature rises Thus, the optical characteristics can be improved.
[0028]
According to the invention described in claim 3, in the invention described in claim 2, the conductor portion on the harness substrate for connecting the pins other than the ground of the two semiconductor lasers has the same resistance and electric capacity as the function of each semiconductor. Therefore, the light emission characteristics of each semiconductor can be improved.
[0029]
According to the invention described in claim 4, in the invention described in claim 1, the semiconductor laser chip is arranged so that the direction in which the divergence angle is large is substantially parallel to the main scanning plane. The optical characteristics can be improved by suppressing the fluctuation of the beam pitch in the sub-scanning direction due to the fluctuation.
[Brief description of the drawings]
FIG. 1 is an emission side front view showing an example of a light source applicable to a multi-beam scanning light source apparatus according to the present invention.
FIG. 2 is a front view of the light source on the side opposite to the emission side.
FIG. 3 is a front view showing an example of a coupling lens applicable to the multi-beam scanning light source device according to the present invention.
FIG. 4 is a plan view showing an embodiment of a multi-beam scanning light source device according to the present invention.
FIG. 5 is a front view showing a harness substrate applicable to the embodiment.
FIG. 6 is an optical arrangement diagram showing an optical system applicable to the embodiment.
FIG. 7 is a perspective view showing a divergent light beam of a light source applicable to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Light source 1a Semiconductor laser chip 1b Stem 1c Holder 2 Light source 2a Semiconductor laser chip 2b Stem 2c Holder 3 Coupling lens system 3a Coupling lens 3b Aperture 4 Cylinder lens 5 Rotating polygon mirror 6 Scanning lens 7 Scanned surface 8 Optical holder 11 Hole 12 Hole 13 Projection 14 Adhesive 15 Ground Pin 16 Ground Pin 17 Conductor Part 18 Conductor Part 19 Conductor Part 20 Conductor Part 21 Conductor Part 22 Harness Substrate 23 Drive Pin 24 Other Functions of the Light Source 1 Other than Driving the Semiconductor Laser and Ground Pin 25 having a function of driving the semiconductor laser of the light source 2 and having a function other than the ground

Claims (4)

Multiple light sources;
A coupling lens system for coupling divergent light beams from a plurality of light sources;
A deflector that deflects the light beam that has passed through the coupling lens system at an equal angular velocity;
A scanning optical system that focuses a plurality of light beams deflected by the deflector toward the surface to be scanned and scans the surface to be scanned at substantially constant speed,
Among the plurality of light sources, an optical system that emits light from at least two light sources, passes through a coupling lens, and travels toward the deflector has an opening angle.
A multi-beam scanning light source device, wherein each of the light sources is a semiconductor laser, and the semiconductor laser chip and a stem for holding the semiconductor laser chip are arranged in the same direction in the main scanning direction. 2. The multi-beam scanning light source according to claim 1, wherein a portion connected to an electrical system for driving each semiconductor laser is constituted by a harness substrate, and a ground of the harness substrate is commonly connected to a ground of each semiconductor laser. apparatus. 3. The conductive wire portion on the harness substrate for connecting pins other than the grounds of the two semiconductor lasers is configured such that the resistance and the capacitance are equivalent to those of the same pin in the function of each semiconductor. Multi-beam scanning light source device. 2. The multi-beam scanning light source device according to claim 1, wherein the semiconductor laser chip is arranged so that a direction with a large divergence angle is substantially parallel to the main scanning plane.

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