JP2009276542A - Light source apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source apparatus which is made compact and in which the position of a collimator lens is easily adjustable. <P>SOLUTION: The light source apparatus 1 is used for an optical scanner. A laser diode 2 emits a beam B. A circuit substrate 32 drives the laser diode 2. A light source holder 34 holds the laser diode 2 and the circuit substrate 32. The collimator lens 7 condenses the beam B. A base 30 holds the collimator lens 7. Male screws 36a and 36b are mounted on mounting arm parts 30a and 30b via mounting parts 34a and 34b, and fix the base 30 and the light source holder 34. The mounting arm parts 30a and 30b are located between the mounting parts 34a and 34b and the circuit substrate 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light source device, and more particularly to a light source device used in an optical scanning device.

  As a conventional light source device, for example, a multi-beam light source device described in Patent Document 1 is known. The multi-beam light source device includes an optical box, a semiconductor laser, a laser holder, and a drive substrate. The semiconductor laser is fixed to the laser holder and connected to the drive substrate. The drive substrate is screwed to the laser holder, and the laser holder is screwed to the optical box. Thereby, the optical box, the laser holder, and the drive substrate are arranged in this order.

  In the multi-beam optical apparatus, as will be described below, since an internal thread is formed in the optical box, the position of the semiconductor laser is difficult to shift during screwing. More specifically, for example, when an internal thread is formed in the laser holder instead of the optical box, the optical box is attached to the laser holder by being pressed against the laser holder by a screw. . Therefore, when screwing the optical box to the laser holder, the screw is screwed into the female screw of the laser holder through the screw hole of the optical box. At this time, the tip of the screw collides with the laser holder and an impact is applied, or a force is applied during the rotation of the screw, so that the position of the laser holder may be shifted.

  On the other hand, in the multi-beam optical device, the laser holder is attached to the optical box by being pressed against the optical box with a screw. Therefore, when screwing the laser holder to the optical box, the laser holder is held in a state where the laser holder is aligned with the optical box, and the screw is attached to the female screw of the optical box through the screw hole of the laser holder. Screw together. At this time, the tip of the screw collides with the optical box and an impact is applied, or a force during rotation of the screw is applied. However, since the optical box is fixed with respect to the main body or the adjusting device, no shift occurs even if an impact or force is applied.

  However, in the multi-beam optical device described in Patent Document 1, it is necessary to form a relief hole in the drive substrate, as described below, and there is a problem that the degree of freedom in the arrangement of the light source driving IC and the wiring becomes low. is there. More specifically, it is preferable that the semiconductor laser is directly connected to the drive substrate without a wiring or the like from the viewpoint of noise reduction. As described above, when the semiconductor laser is directly attached to the drive substrate, the laser holder and the drive substrate are arranged in parallel through a slight gap. Therefore, there is no space for screwing the laser holder and the optical box. Therefore, like the multi-beam optical apparatus described in Patent Document 1, it is necessary to form a relief hole in the drive substrate and screw the laser holder and the optical box through the relief hole.

However, when a relief hole is formed in the drive substrate, a light source driving IC and wiring cannot be provided in the relief hole, so that the degree of freedom of arrangement of the light source driving IC and wiring becomes low.
Japanese Patent Laid-Open No. 10-319336

  SUMMARY OF THE INVENTION An object of the present invention is to provide a light source device that is less likely to be displaced when a light source holder is attached to a base, and that can design a circuit board of a laser diode with a high degree of freedom.

  A light source device according to an aspect of the present invention is a light source device used in an optical scanning device, a light source that emits a beam, a circuit board that drives the light source, and a first holder that holds the light source and the circuit board. A collimator lens for condensing the beam, a second holder for holding the collimator lens, and the first holder and the second holder by being attached to the second holder via the first holder. A fixing member that fixes the second holder, wherein the second holder is formed at a portion where the first holder and the second holder are joined to each other. It is located between the circuit boards.

  In the light source device, when the first holder is attached to the second holder, deviation hardly occurs, and the circuit board of the light source can be designed with a high degree of freedom.

  Embodiments of a light source device according to the present invention will be described below with reference to the accompanying drawings.

(Outline of optical scanning device)
First, an outline of an optical scanning device to which a light source device according to the present invention is applied will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an outline of an optical scanning device. In FIG. 1, the optical scanning device generally includes a light source device 1, a cylindrical lens 11, a polygon mirror 12, three fθ lenses 13, 14 and 15, a cylindrical lens 16, and a plane mirror 17.

  The light source device 1 includes a laser diode 2 as a light source that emits a beam B, a mirror 5 that bends the optical path of the beam B, and a collimator lens 7 as a condensing unit. The beam B radiated from the laser diode 2 is reflected by the mirror 5, the optical path is bent by 90 degrees, and further collected by the collimator lens 7 into parallel light (or convergent light).

  The beam B that has passed through the collimator lens 7 reaches the polygon mirror 12 via the cylindrical lens 11. The cylindrical lens 11 condenses the beam B in the form of a long line in the main scanning direction near the reflecting surface of the polygon mirror 12. The polygon mirror 12 is rotationally driven at a constant angular velocity in the direction of arrow a. The beam B is deflected and scanned at an equal angular velocity on each reflecting surface based on the rotation of the polygon mirror 12, passes through the fθ lenses 13, 14, 15 and the cylindrical lens 16, and is reflected downward by the plane mirror 17. Thereafter, the beam B forms an image on the photosensitive drum 25 and scans in the arrow b direction.

  The fθ lenses 13, 14, and 15 have a function of correcting the main scanning speed on the photosensitive drum 25 at a constant speed (distortion aberration correction) for the beam B deflected at a constant angular speed by the polygon mirror 12. Similar to the cylindrical lens 11, the cylindrical lens 16 has power only in the sub-scanning direction, and the two cylindrical lenses 11 and 16 cooperate to correct the surface tilt error of the polygon mirror 12.

  The photosensitive drum 25 is driven to rotate at a constant speed in the direction of arrow c, and is subjected to main scanning in the direction of arrow b by the polygon mirror 12 and the fθ lenses 13, 14, and 15, and sub scanning in the direction of arrow c of the photosensitive drum 25. An image (electrostatic latent image) is written on the photosensitive drum 25.

(Configuration of light source device)
Next, the structure of the light source device 1 will be described with reference to the drawings. 2 to 4 are configuration diagrams of the light source device 1. More specifically, FIG. 2A is a front view of the light source device 1, and FIG. 2B is a side view of the light source device 1. FIG. 3 is a top view of the light source device 1, and FIG. 4 is a bottom view of the light source device 1. In the following description, the x-axis direction is a direction parallel to the optical axis of the beam B that has passed through the collimator lens 7, the y-axis direction is a direction orthogonal to the x-axis direction on the horizontal plane, and the z-axis direction. Means a direction parallel to the optical axis of the beam B emitted by the laser diode 2.

  The light source device 1 includes a laser diode 2, a mirror 5, a collimator lens 7, a base base 30, a circuit board 32, a light source holder 34, male screws 36 a and 36 b, a lens barrel 38, and a leaf spring 40. Since the laser diode 2, the mirror 5, and the collimator lens 7 have already been described, further description will be omitted.

  The circuit board 32 is a circuit for driving the laser diode 2 to which the laser diode 2 is electrically connected. The circuit board 32 is arranged to be perpendicular to the optical axis of the beam B emitted from the laser diode 2 (that is, parallel to the x-axis direction and the y-axis direction). The circuit board 32 is formed with holes hc, hd, and he for attaching the light source holder 34.

  The light source holder 34 is a holder for holding the laser diode 2 and the circuit board 32, and is manufactured by bending a metal plate. The light source holder 34 is attached to the circuit board 32 so as to be parallel to the circuit board 32. More specifically, the light source holder 34 has attachment portions 34c, 34d, and 34e formed by being bent perpendicularly to the xy plane. The light source holder 34 has the mounting portions 34c, 34d, 34e inserted into holes hc, hd, he formed in the circuit board 32, so that the circuit board 32 is parallel to the circuit board 32. Is attached. As a result, the optical axis of the beam B emitted from the laser diode 2 is perpendicular to the light source holder 34.

  As shown in FIGS. 2 to 4, the light source holder 34 has attachment portions 34 a and 34 b that project in both the positive and negative directions in the y-axis direction. The mounting portions 34a and 34b are formed with holes for allowing the male screws 36a and 36b to pass therethrough.

  The lens barrel 38 is a holder that holds the collimator lens 7 and has a cylindrical shape.

  The base table 30 is a holder that holds the mirror 5, the light source holder 34, and the lens barrel 38. For example, the base table 30 is a table manufactured by a casting method. As shown in FIG. 2B, the base 30 has mounting arm portions 30a and 30b that extend in the z-axis direction and bend and extend in the x-axis direction at the tip thereof. . The male screws 36a and 36b are attached to the attachment arm portions 30a and 30b via the attachment portions 34a and 34b, thereby fixing the attachment portions 34a and 34b and the attachment arm portions 30a and 30b.

  More specifically, in FIG. 2B, a female screw (not shown in FIG. 2) extending in the z-axis direction is formed on the lower side of the mounting arm portions 30a and 30b in the z-axis direction. . The mounting portions 34a and 34b of the light source holder 34 are arranged on the lower side in the z-axis direction of the mounting arm portions 30a and 30b, and the male screws 36a and 36b are changed from the lower side in the z-axis direction to the female screw with the mounting portions 34a and 34b interposed therebetween. Screw together. Thereby, the light source holder 34 is fixed on the base table 30, and the laser diode 2 and the circuit board 32 are also fixed on the base table 30. Further, the attachment arm portions 30a and 30b of the base table 30 are respectively provided between the attachment portions 34a and 34b and the circuit board 32 at portions where the attachment arm portions 30a and 30b are joined to the attachment portions 34a and 34b. Come to be located.

  Further, in the base table 30, a mirror 5 is attached to the lower side of the laser diode 2 in the z-axis direction. In FIG. 2B, the mirror 5 needs to reflect the beam B incident from the upper side in the z-axis direction in the x-axis direction, so that the base 5 is rotated 45 degrees from the xy plane around the y-axis. It is attached to the base 30.

  The lens barrel 38 is attached to the base 30 on the left side in the x-axis direction with respect to the mirror 5 as shown in FIG. More specifically, as shown in FIG. 4, the base table 30 is formed with a mounting groove 30 c that extends in the x-axis direction and faces the negative direction side in the z-axis direction. As shown in FIG. 2A, the lens barrel 38 is attached to the base 30 so that the circuit board 32 side (that is, the upper side in the z-axis direction) contacts the attachment groove 30c. The leaf spring 40 has one end attached to the base table 30 and the other end contacting the lens barrel 38, thereby pressing the lens barrel 38 against the attachment groove 30c.

  According to the light source device 1, as will be described below, when the light source holder 34 is attached to the base base 30, it is difficult for deviation to occur, and the circuit board 32 of the laser diode 2 can be designed with a high degree of freedom.

  More specifically, in the multi-beam optical apparatus described in Patent Document 1, since the female screw is formed in the optical box, the position of the semiconductor laser is difficult to shift when screwing. However, in the multi-beam optical device described in Patent Document 1, it is necessary to form a relief hole in the drive substrate, and there is a problem in that the degree of freedom in the arrangement of the light source drive IC and the wiring becomes low. The semiconductor laser is preferably connected directly to the drive substrate without a wiring or the like from the viewpoint of noise reduction. As described above, when the semiconductor laser is directly attached to the drive substrate, the laser holder and the drive substrate are arranged in parallel through a slight gap. Therefore, there is no space for screwing the laser holder and the optical box. Therefore, like the multi-beam optical apparatus described in Patent Document 1, it is necessary to form a relief hole in the drive substrate and screw the laser holder and the optical box through the relief hole. Such a relief hole has caused a low degree of freedom in designing the drive substrate.

  On the other hand, in the light source device 1, the mounting arm portions 30 a and 30 b of the base table 30 are positioned between the mounting portions 34 a and 34 b of the light source holder 34 and the circuit board 32, respectively. That is, the light source holder 34, the base table 30, and the circuit board 32 are arranged in this order at the joint between the attachment arm portions 30a and 30b and the attachment portions 34a and 34b. As a result, without making a hole in the circuit board 32, a female screw can be formed in the base table 30, and the male screws 36 a and 36 b can be screwed into the female screw of the base table 30 via the light source holder 34. Therefore, in the light source device 1, the light source holder 34 is not easily displaced when attached to the base table 30, and the circuit board 32 of the laser diode 2 can be designed with a high degree of freedom. Thereby, for example, the driving IC for the laser diode 2 can be arranged in the vicinity of the laser diode 2 in order to reduce noise.

  Moreover, in the light source device 1, as will be described below, it is easy to form a female screw to which the male screws 36a and 36b are attached. More specifically, in the light source device 1, a female screw is formed on the base table 30. Since the base 30 is a member to which the light source holder 34, the mirror 5 and the like are attached and is fixed to the optical scanning device, it is larger and more robust than the light source holder 34. Therefore, it is easier to form the female screw in the light source device 1 than in the light source holder 34 formed by bending the metal plate.

  Next, the operation of attaching the light source holder 34 to the base table 30 will be described with reference to the drawings. FIG. 5 is a configuration diagram of the light source device 1 in a state before the light source holder 34 is attached to the base table 30. FIG. 5A is a side view, and FIG. 5B is a bottom view.

  As shown in FIG. 5A, the light source holder 34 is translated from the negative direction in the x-axis direction to the positive direction, and the attachment arm portions 30a and 30b are provided between the attachment portions 34a and 34b and the circuit board 32. Insert. Thereby, the attachment parts 34a and 34b come in contact with the attachment arm parts 30a and 30b, respectively. Thereafter, male screws 36 a and 36 b are attached from the lower side in the z-axis direction of FIG. 5A to fix the light source holder 34 to the base table 30. As a result, the light source holder 34 is attached to the base table 30.

  By the way, when the light source holder 34 is attached to the base table 30, relative to the main surface of the circuit board 32 with the attachment arm portions 30 a and 30 b being close to the circuit board 32 as shown in FIG. Moving. Therefore, as shown in FIG. 5B, when the light source holder 34 is attached to the base base 30, the average height of the electronic components mounted on the circuit board 32 in the region α through which the attachment arm portions 30a and 30b pass is provided. The height is preferably lower than the average height of the electronic components mounted in other regions. This will be described in detail below.

  The laser diode 2 is preferably mounted directly on the circuit board 32 in order to reduce the influence of noise. Therefore, the distance between the laser diode 2 and the circuit board 32 depends on the length of the terminal of the laser diode 2 and is relatively small. For this reason, the distance between the light source holder 34 holding the laser diode 2 shown in FIG. 5B and the circuit board 32 is also relatively small.

  Here, the attachment arm portions 30 a and 30 b are inserted between the circuit board 32 and the attachment portions 34 a and 34 b while being translated on the circuit board 32. At this time, since the distance between the circuit board 32 and the attachment portions 34 a and 34 b is relatively small, the attachment arm portions 30 a and 30 b relatively move near the circuit board 32. Therefore, if a relatively high electronic component is mounted in the region α of the circuit board 32, the electronic component collides with the circuit board 32.

  Therefore, in the light source device 1, as shown in FIG. 5B, the light source device 1 is mounted on the region α on the circuit board 32 on the positive direction side in the x-axis direction from the mounting portions 34 a and 34 b when viewed in plan from the z-axis direction. The average height of the electronic components is made lower than the average height of the electronic components mounted in other areas. This prevents the attachment arm portions 30 a and 30 b from colliding with the electronic components on the circuit board 32 when the light source holder 34 is attached to the base table 30.

(Other embodiments)
The light source device according to the embodiment of the present invention is not limited to the light source device 1. Therefore, the light source device 1 can be appropriately changed within the scope of the gist thereof. FIG. 6 is a configuration diagram of a light source device 1a according to another embodiment. Fig.6 (a) is a front view of the light source device 1a, and FIG.6 (b) is a side view of the light source device 1a.

  In the light source device 1 illustrated in FIG. 2, the circuit board 32 is provided on the upper side of the base table 30, but the mounting position of the circuit board 32 is not limited thereto. For example, as shown in FIG. 5, a circuit board 32 may be provided on the negative direction side in the x-axis direction. In this case, since it is not necessary to bend the optical path of the beam B, the mirror 5 is unnecessary.

It is the block diagram which showed the outline | summary of the optical scanning device. It is a block diagram of the light source device which concerns on one Embodiment of this invention. It is a block diagram of the light source device which concerns on one Embodiment of this invention. It is a block diagram of the light source device which concerns on one Embodiment of this invention. It is a block diagram of the light source device of the state before a light source holder is attached to a base stand. It is a block diagram of the light source device which concerns on other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a Light source device 2 Laser diode 5 Mirror 7 Collimator lens 11 Cylindrical lens 30 Base stand 30a, 30b Mounting arm part 30c Mounting groove 32 Circuit board 34 Light source holder 34a-34e Mounting part 36a, 36b Male screw 38 Lens barrel

Claims (4)

In the light source device used in the optical scanning device,
A light source that emits a beam;
A circuit board for driving the light source;
A first holder for holding the light source and the circuit board;
A collimator lens for condensing the beam;
A second holder for holding the collimator lens;
A fixing member that fixes the first holder and the second holder by being attached to the second holder via the first holder;
With
The second holder is located between the first holder and the circuit board at a portion where the first holder and the second holder are joined;
A light source device characterized by the above. The second holder is formed with a female screw,
The fixing member is a male screw and is screwed into the female screw with the first holder interposed therebetween;
The light source device according to claim 1. In the portion where the first holder and the second holder are joined, the second holder is inserted between the first holder and the circuit board from a direction parallel to the circuit board. thing,
The light source device according to claim 1, wherein: The circuit board is disposed parallel to the beam that has passed through the collimator lens;
The light source device according to any one of claims 1 to 3, wherein:

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