JP2001015847A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the electrical stability of a semiconductor laser light source in a simple and inexpensive structure. SOLUTION: In a state where a circuit board 57 is mounted on a laser holder, the seating face of a fixing screw 56 is electrically connected to a grounding pattern 60 coming into contact with it. The stem of a semiconductor laser light source at a potential of 0 V is brought into contact with the flange of a cylinder to allow the laser holder to home the same potential of 0 V, and furthermore the seating face of the fixing screw 56 is in contact with the grounding pattern 60, thereby the laser holder is connected to the grounding pattern 60 of the drive circuit of the semiconductor laser ray source of the circuit board 57. As mentioned above, the metal laser holder is connected to the grounding pattern 60 of the drive circuit of the circuit board 57 with the fixing screw 56, so that the electrical stability of the light source device where a semiconductor laser light source of cathode common type in which a laser holder carries 0 V can be improved.

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 used for an image recording device such as a laser beam printer or a laser facsimile, or a pickup unit of an optical disk using a semiconductor laser light source.

[0002]

2. Description of the Related Art FIG. 6 is a perspective view of a scanning optical device used in an image recording apparatus. A unitized light source device 2 is attached to a side wall of an optical box 1 and is located at a predetermined position on the bottom of the optical box 1. Is a cylindrical lens 3, a polygon mirror 4,
An imaging lens 5 and a folding mirror 6 are arranged, and a detection mirror 7 and a photodetector 8 for detecting a scanning start signal are further arranged. The light source device 2, the cylindrical lens 3, the polygon mirror 4, the imaging lens 5, the return mirror 6, the detection mirror 7, and the photodetector 8 are housed in a housing of the optical box 1. The opening is closed by a lid (not shown).

A laser beam L emitted from a light source device 2 is applied to a polygon mirror 4 through a cylindrical lens 3, scanned and deflected by the polygon mirror 4, reflected by a turning mirror 6 through an imaging lens 5, and exposed to light (not shown). An image is formed on the surface of the drum. The laser beam L formed on the photosensitive drum forms an electrostatic latent image by main scanning by rotation of the polygon mirror 4 and sub-scanning by rotation of the photosensitive drum. A part of the laser light L deflected and scanned by the polygon mirror 4 is introduced into the photodetector 8 by the detection mirror 7, and starts the write modulation of the light source device 2 by the output signal of the photodetector 8.

FIG. 7 shows a sectional view of a conventional light source device.
The light source device 2 includes a semiconductor laser light source 9 that emits laser light L, a collimator lens 10 that collimates the laser light L to have a predetermined cross-sectional shape, and a circuit board 11 on which an IC for driving the semiconductor laser light source 9 is mounted. Are united to form a unit.

The semiconductor laser light source 9 is a laser holder 1
The second cylindrical portion 13 is press-fitted and held on the inner peripheral surface 15 on the flange 14 side, and the other side of the cylindrical portion 13 has a lens holder 16.
The inner peripheral surface 18 of the cylindrical portion 17 and the outer peripheral surface of the cylindrical portion 13 of the laser holder 12 are fitted and fixed. At the tip of the lens holder 16, a mounting hole portion 19 for accommodating the collimator lens 10 and a lens holding portion 21 having an optical stop 20 for shaping the laser beam L into a spot beam of a predetermined shape are integrally formed.

In the laser holder 12, the cylindrical portion 13
A fitting ring 22 provided between the optical box 1 and the flange 14 is inserted into a fitting hole 23 of the optical box 1, and is fixed by a fixing screw 24 at a mounting section 25 provided below the flange 14. It is fixed to. Further, the circuit board 11 is fixed to a screw hole 27 provided in the mounting portion 26 on the upper side of the flange 14 by a fixing screw 28, and the lead pin 29 of the semiconductor laser light source 9 is electrically connected to the circuit board 11 through the through hole 30. It is connected to the.

In such a configuration, the semiconductor laser light source 9 is provided on the inner peripheral surface 15 of the cylindrical portion 13 of the laser holder 12.
And is fixedly held. The circuit board 11 is fastened and fixed to the laser holder 12 by screws 28 in a state where the lead pins 29 of the semiconductor laser light source 9 pass through the through holes 30 provided in the circuit board 11. Lead pin 2
9 is soldered to the circuit board 11 and the collimator lens 1
Reference numeral 0 is fitted into the mounting hole 19 of the lens holding portion 21 and fixedly held by bonding or heat welding.

In the lens holder 16, a radial gap between the circumferential surface 18 of the cylindrical portion 17 for holding the collimator lens 10 and the outer peripheral surface of the cylindrical portion 13 of the laser holder 12 for holding the semiconductor laser light source 9. Then, the optical axis of the laser beam from the semiconductor laser light source 9 and the collimator lens 10 are aligned, and the collimator lens 10 is focused by sliding in the optical axis direction. Thereafter, the light source device 2 in which the lens holder 16 and the laser holder 12 are bonded and fixed to each other is completed.

FIG. 8 shows a front view of a portion where the adjusted and assembled circuit board 11 is attached to the laser holder 12. Since the ground pattern 31 on the circuit board 11 for driving the semiconductor laser light source 9 is not provided, the laser holder 12 is electrically disconnected from the ground pattern 31.

[0010]

However, in the above-mentioned conventional example, electrical noise is generated by a high-frequency signal generated from a drive circuit of the semiconductor laser light source 9 and the like, and the semiconductor laser light source 9 cannot be accurately modulated.
In addition, radiated noise, which radiates electromagnetic waves to the outside of the image forming apparatus and adversely affects surrounding electric devices and the human body, also poses a problem. Further, in the light source device 2 in which the laser holder 12 for holding the semiconductor laser light source 9 is made of a metal conductive material, the potential of the laser holder 12 becomes unstable, and the noise generation situation is further deteriorated. There is a point.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a light source device having a simple and inexpensive configuration and having improved electrical stability of a semiconductor laser light source.

[0012]

A light source device according to the present invention for achieving the above object comprises a laser holder for holding a semiconductor laser light source, and a collimator lens for forming a laser beam into a predetermined beam shape. In a light source device comprising a lens holder for arranging a semiconductor laser light source at a predetermined position and a circuit board unit for driving and controlling the semiconductor laser light source, the laser holder comprises at least a portion in contact with the semiconductor laser light source made of a conductive material. The portion is electrically connected to a ground pattern of a semiconductor laser light source driving circuit on the circuit board portion.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 is a sectional view of a light source device according to a first embodiment. A cathode common type semiconductor laser light source 40 in which a potential of a stem 40a as a structure is OV is provided in a cylindrical portion 42 of a laser holder 41 made of metal.
Is press-fitted and held on the inner peripheral surface 44 on the flange 43 side.
On the distal end side of the cylindrical portion 42, the lens holder 45 has a circumferential surface 47 of the cylindrical portion 46 and the cylindrical portion 42 of the laser holder 41.
Is fitted and fixed to the outer peripheral surface of the. At the tip of the lens holder 45, a mounting hole 49 for accommodating the collimator lens 48 and an optical diaphragm 50 are integrally formed.

The cylindrical part 42 of the laser holder 41 is provided with a fitting ring part 51 for positioning at the joint part with the flange 43. When fitting into an optical box (not shown), this fitting ring part 51 is used. The part 51 is inserted into the fitting hole of the optical box and fitted and fixed. At the lower mounting portion 52 of the flange 43, the fixing screw 53 is screwed into the laser holder 41.
Is fixed to the optical box. A screw hole 55 is provided in the mounting portion 54 on the upper side of the flange 43, and a fixing screw 56 is screwed into the screw hole 55 in the mounting portion 54 so that the circuit board 57 is fixed to the laser holder 41. I have. The lead pins 40b of the semiconductor laser light source 40 are electrically connected to the circuit board 57.

FIG. 2 shows the laser holder 41 of the circuit board 57.
FIG. 3 is a cross-sectional view of a portion to be mounted on the laser holder 41, and FIG. 3 shows a plan view of the circuit board 57.
A ground pattern 60 connected to a ground line is formed on the surface of the device.

In the above-described configuration, the semiconductor laser light source 40 is directly pressed into the inner peripheral surface 44 of the cylindrical portion 42 of the laser holder 41 and fixedly held. The circuit board 57 and the laser holder 41 are fixed by a fixing screw 56 obtained by performing a copper plating process on a steel material in order to improve conductivity. The lead pins 40b of the semiconductor laser light source 40 are
7, whereby the seating surface of the fixing screw 56 comes into contact with the ground pattern 60 to be electrically connected.

The collimator lens 48 includes a lens holder 45
And is fixedly held by bonding or heat welding. The laser holder 41 for holding the semiconductor laser light source 40 and the lens holder 45 for holding the collimator lens 48 have a circumference 47 of the cylindrical portion 46 of the lens holder 45 and a diameter of the outer circumference of the cylindrical portion 42 of the laser holder 41. The fitting is fixed in the gap range in the direction. Here, the optical axis of the laser beam L of the semiconductor laser light source 40 and the collimator lens 48 are aligned, and the collimator lens 48 is focused by sliding the lens holder 45 in the optical axis direction. Thereafter, the lens holder 45 and the laser holder 41 are integrated by bonding or the like to complete the light source device.

In the light source device of this embodiment, the laser holder 41 is brought to the same potential (0 V) by the contact between the stem 40 a of the semiconductor laser light source 40 having a potential of 0 V and the flange 43 of the cylindrical portion 42, and furthermore, the fixing screw When the seating surface of 56 contacts the ground pattern 60, it is electrically connected to the ground pattern 60 of the drive circuit of the semiconductor laser light source 40 on the circuit board 57.

As described above, the metal laser holder 41 is used.
And the ground pattern 60 of the drive circuit of the circuit board 57 are electrically connected by the fixing screw 56. Therefore, the electrical stability of the light source device using the cathode common type semiconductor laser light source 40 in which the laser holder 41 becomes 0V To
It can be improved simply and at low cost. The laser holder 41 may not be made of metal, but may be formed of a conductive material at a portion in contact with the slam 40a of the semiconductor laser light source 40, and may be electrically connected to the ground pattern 60.

FIG. 4 is a sectional view of a portion where the circuit board 57 of the second embodiment is attached to the laser holder 41, and FIG. 5 is a plan view. The ground pattern 61 of the drive circuit for driving the semiconductor laser light source 40 and the pattern 62 provided around the screw hole 55 are connected via a capacitor 63.
Other configurations, adjustments, and assembling methods are the same as those in the first embodiment, and the semiconductor laser light source 40 is of an anode common type in which the stem 40a has the same potential as the applied voltage.

Thus, the metal laser holder 4
2 and the ground pattern 61 of the drive circuit of the semiconductor laser light source 40 are electrically connected via a capacitor 63.
Therefore, the laser holder 42 and the ground pattern 61 are electrically insulated from each other in a DC manner, and the laser holder 4
Since the second and ground patterns 61 are connected, it is possible to achieve both protection of the light source device using the semiconductor laser light source 40 of the anode common type and electrical stability.

[0022]

As described above, in the light source device according to the present invention, the portion in contact with the semiconductor laser light source is made of a conductive material, and this conductive material portion is grounded to the semiconductor laser light source drive circuit on the circuit board portion. By electrically connecting to the pattern, the semiconductor laser light source and its holding member can be improved in electrical stability with a simple and inexpensive configuration, so that noise generation is suppressed and safety and reliability are improved. A highly compact scanning optical device or image recording device can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a light source device according to a first embodiment.

FIG. 2 is a sectional view of a mounting portion of the circuit board.

FIG. 3 is a plan view.

FIG. 4 is a sectional view of a mounting portion of a circuit board according to a second embodiment.

FIG. 5 is a plan view.

FIG. 6 is a perspective view of a conventional scanning optical device.

FIG. 7 is a cross-sectional view of the light source device.

FIG. 8 is a partial front view of a circuit board.

[Explanation of symbols]

 Reference Signs List 40 semiconductor laser light source 41 laser holder 45 lens holder 48 collimator lens 50 optical aperture 52, 54 mounting part 53, 56 fixing screw 55 screw hole 57 circuit board 60, 61 ground pattern 62 pattern 63 capacitor

Claims (3)

[Claims] 1. A laser holder for holding a semiconductor laser light source, a lens holder for holding a collimator lens for shaping a laser beam into a predetermined beam shape and disposing the semiconductor laser light source at a predetermined position, and driving the semiconductor laser light source And a circuit board portion to be controlled. In the light source device, at least a portion of the laser holder in contact with the semiconductor laser light source is made of a conductive material, and the portion is a ground pattern of a semiconductor laser light source driving circuit on the circuit board portion. A light source device electrically connected to the light source. 2. The circuit board portion and the laser holder are fixed by a member made of a conductive material or a screw whose surface has been subjected to a conductive treatment, and around a screw hole of the circuit board portion screwed to the screw. 2. The light source device according to claim 1, wherein the provided pattern is formed integrally with a ground pattern of the semiconductor laser light source drive circuit, and the pattern and the bearing surface of the screw are in contact with each other. 3. The light source device according to claim 2, wherein the pattern and the ground pattern are connected via a capacitor.