JPH08220463A - Optical scanner mirror - Google Patents

Abstract

PURPOSE: To reduce the moment of inertia at the time of rocking while securing sufficient strength(rigidity). CONSTITUTION: This device possesses a rocking shaft 20 having a shaft center D which is aligned with a reflection surface 16A, and is provided with a mirror main body 14 rocking is the range of a specified angle centering the rocking shaft 20. Plural follow parts are provided on the rear surface side of the reflection surface 16A of the mirror main body 14. Thus, lightening is weight by the portion of the hollow part is attained, and when such a hollow part that the strength(rigidity) is not deteriorated more than needed is provided, a load at the time of high-speed rocking, that means, the moment of the inertia is reduced while securing the sufficient strength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirror for an optical scanning device, and more particularly to a mirror for an optical scanning device which is suitable for a laser repair device or the like which requires high speed scanning of a light beam.

The present invention can be used in all light beam scanning techniques, but among them, the beam scanning technique in the above-described apparatus is highly useful.

[0003]

2. Description of the Related Art As shown in FIG. 7, a mirror main body 50 constituting a conventional mirror for an optical scanning device has a rectangular shape (or a circular shape) having a reflecting surface 50A formed on one surface by vapor deposition of silver, aluminum or the like. ) Is often made of parallel plate glass. The mirror main body 50 is held by a bearing mechanism (not shown) housed in an optical scanning device (optical scanner) body 54 via a shaft 52, and an axis C of the shaft 52 (this axis center is driven by a drive motor, not shown). Is set so as to substantially coincide with the reflecting surface 50A) and is swung within a predetermined angle range. In addition, in FIG. 7, the shaded portion indicates the light diameter.

[0004]

In order to increase the light diameter of the scanning light beam, it is necessary to increase the size of the reflecting surface 50A. In this case, the weight (mass) of the mirror body 50 is increased. As a result, the moment of inertia increases and the load becomes high, and the light beam is scanned at high speed.
It was an obstacle when swinging at high speed.

On the other hand, when the mirror main body 50 is made thin in order to reduce the moment of inertia due to the weight reduction, the rigidity (strength) is lowered, and the light beam is deteriorated due to an increase in the flexural deformation amount of the reflecting surface 50A of the mirror main body 50. There was an inconvenience.

The present invention has been made in view of the inconveniences of the prior art as described above, and an object thereof is to reduce the moment of inertia at the time of rocking while ensuring sufficient strength (rigidity). Another object of the present invention is to provide a mirror for an optical scanning device.

[0007]

SUMMARY OF THE INVENTION The present invention is for an optical scanning device having a mirror body having a swing axis parallel to a reflecting surface and swinging about the swing axis within a predetermined angle range. In the mirror, a plurality of hollow portions are provided on the back surface side of the reflection surface of the mirror body. In this case, since the mirror body is provided with the plurality of hollow portions, the weight can be reduced accordingly. Therefore, if the hollow portion is provided so that the rigidity (strength) does not decrease more than necessary, it is possible to reduce the load during high-speed rocking, that is, the moment of inertia, while ensuring a certain level of strength.

The mirror body may include a flat plate having a reflecting surface formed on one surface thereof and a reinforcing member joined to the flat plate and having a plurality of hollow portions. In this case, since the reinforcing member is included as a constituent member, sufficient strength can be secured by the reinforcing member even if the flat plate (mirror) is made as thin as possible. Since a plurality of hollow portions are provided, the weight can be reduced accordingly. Therefore, it is possible to reduce the load during high-speed rocking, that is, the moment of inertia, while ensuring sufficient strength.

In this case, in order to prevent deformation of the reflecting surface formed on the flat plate, it is desirable that the flat plate and the reinforcing member have approximately the same coefficient of thermal expansion, and the flat plate and the reinforcing member are bonded together. It is desirable to bond with an adhesive having a small time shrinkage (or expansion).

Further, it is preferable that the hollow portion is mainly provided at a position apart from the swing shaft. The moment of inertia about an axis of an object is the sum of the product of the mass of a small part of the object and the square of the distance of the part from the axis, and therefore the hollow part is separated from the swing axis. It is clear that when the main body is provided mainly at the above position, the moment of inertia is significantly smaller than that of the case where the hollow parts are provided with the same mass concentrated at the position close to the swing axis. Therefore, when the hollow portion is mainly provided at a position away from the swing shaft, the moment of inertia during swing can be effectively reduced.

Further, the reinforcing member may be composed of a honeycomb structure. Since the honeycomb structure is mainly used in a part such as an auxiliary wing or a tail of an aircraft which requires a certain amount of strength and needs to be lightweight, when the reinforcing member is formed of the honeycomb structure. In addition, it is possible to effectively reduce the weight while ensuring sufficient strength.

When using this honeycomb structure, it is desirable to adopt a so-called honeycomb sandwich structure in which the honeycomb structure made of a lightweight member is used as a core and the core is sandwiched between two plates. This is because such a laminated structure is light and has high compression rigidity.

[0013]

【Example】

<< First Embodiment >> A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows an optical scanner 10 to which a mirror for an optical scanning device according to the first embodiment is applied. The optical scanner 10 includes a mirror body 14 that swings in a predetermined angle range around a shaft 20 that is a swing shaft. The mirror body 14 includes a mirror 16 made of thin parallel plate glass as a rectangular flat plate having a reflecting surface 16A formed by vapor deposition of silver, aluminum or the like on one surface,
The reinforcing member 18 is formed of a thick member having the same shape and joined to the mirror 16.

The mirror body 14 is held by a bearing mechanism (not shown) housed in the optical scanner body 22 via a shaft 20, and the shaft 2 is driven by a drive motor (not shown).
It swings in a predetermined angle range around the axis D of 0. Here, the axis D is set in the vertical direction within a plane that substantially coincides with the reflecting surface 16A. In addition,
In FIG. 1, the shaded portion indicates the light diameter.

The mirror 16 and the reinforcing member 18 are joined by using an adhesive having a small shrinkage rate (or expansion rate) at the time of bonding.

In this embodiment, as shown in FIG. 2, a plurality of round holes 24 as hollow portions are intensively formed at both ends of the reinforcing member 18 in the longitudinal direction, that is, at positions far from the axis D. Has been done.

Therefore, the mirror body 14 of the present embodiment is
The circular holes 24, 24, ... Are lighter in weight than the structure of the mirror body 50 of the conventional example described above, and the moment of inertia at the time of rocking is reduced accordingly.

Here, the circular holes 24 are concentratedly provided at positions apart from the axis D, as described above, because the moment of inertia with respect to the axis D is a minute portion of the mirror body 14. Since it is the sum of the product of the mass and the square of the distance from the axis of the part, it is possible to effectively reduce the moment of inertia by providing the round hole 24 at a position as far from the axis D as possible. Because you can.

Also, the hollow portion is not a round hole but a round hole (through hole).
The reason for setting 24 is that, if the diameter is the same, the volume of the hollow portion is larger in the through hole, and the weight can be reduced accordingly. For the same reason, the weight can be reduced as the thickness of the mirror 16 is smaller than the thickness of the reinforcing member 18 having the round holes 24.

Inertia is obtained by using the design example of the prior art as shown in FIGS. 3A and 3B and the design example according to the first embodiment as shown in FIGS. 4A and 4B. Comparing the moment and the rigidity, the moment of inertia about the rotation axis is about 84.
%, And the amount of distortion of the reflecting surface due to inertia is about 84%. Here, it is assumed that both are made of the same material.

However, in the example of FIG. 3, the outer shape of the mirror body 50 has a width of 40 mm, a height of 32 mm and a thickness of 5 mm.
In the example of FIG. 4, the outer shape of the mirror 16 has a width of 40 mm, a height of 32 mm, and a thickness of 1 mm. The outer shape of the reinforcing member 18 was 40 mm in width, 32 mm in height, and 4 mm in thickness.
The reinforcing member 18 has round holes 24 having a diameter of 4 mm and two holes at both ends.
A total of 24 holes are drilled for each row. The reinforcing member 1
The inner two rows of round holes 24 of FIG. 8 are arranged with their centers separated by 25 mm, and the outer two rows of round holes 24 are arranged with their centers separated by 35 mm.

As described above, according to the first embodiment, the strength (rigidity) is sufficiently ensured by the reinforcing member 18 while the load at the time of high-speed rocking, that is, the reduction of the moment of inertia and the amount of distortion of the reflecting surface is reduced. It can be reduced.

In the first embodiment, the case where the mirror body 14 is composed of the two members of the mirror 16 and the reinforcing member 18 has been exemplified, but this is because the round hole 24 as the hollow portion is easily formed. Although configured in this way, the present invention is not limited to this, and a reflecting surface may be formed on the surface of a single glass plate, and a round hole or the like that is not a through hole may be provided on the back surface side. . Further, it goes without saying that the hollow portion is not limited to the round hole.

Considering the influence of temperature change based on laser energy on the deformation of the reflecting surface during scanning of laser light, the reinforcing member 18 is preferably made of a member having a coefficient of thermal expansion equivalent to that of the mirror 16. .

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. Here, components that are the same as or equivalent to those in the first embodiment described above will be assigned the same reference numerals and their description will be simplified or omitted.

FIG. 5 shows the structure of an optical scanner 30 to which a mirror for an optical scanning device according to the second embodiment is applied. This optical scanner 30 is characterized in that a mirror body 32 is provided instead of the mirror body 14 in the first embodiment.

The mirror body 32 has a so-called honeycomb sandwich structure composed of the mirror 16, the first reinforcing member 34, and the second reinforcing member 36.

This will be described in more detail. Mirror body 32
As shown in FIG. 6, the first reinforcing member 34 made of a honeycomb structure is sandwiched between the mirror 16 and the second reinforcing member 36 made of a thin and lightweight metal plate as a core, It has a laminated structure in which these three members are joined together. The first reinforcing member 34 can be made of a light material such as plastic, and has a large number of hollow portions, so that it is extremely lightweight as a whole. On the other hand, the honeycomb sandwich structure is used for the tail of an aircraft and the like, and is known to have a very high compression rigidity.

According to the second embodiment constructed as described above, the same effect as that of the first embodiment can be obtained, and the first reinforcing member 34 is composed of the honeycomb structure. It is possible to significantly reduce the weight of the mirror main body 32 while ensuring sufficient rigidity, and thus it is possible to greatly reduce the load during high-speed swing, that is, the moment of inertia.

[0031]

As described above, according to the present invention,
It is possible to reduce the load during high-speed rocking, that is, the moment of inertia, while ensuring sufficient strength (rigidity). There is an excellent effect that has never been seen.

In particular, according to the third aspect of the invention, it becomes possible to effectively reduce the moment of inertia when swinging.

According to the invention described in claim 4, it is possible to effectively reduce the weight while sufficiently securing the strength.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of an optical scanner according to a first embodiment.

FIG. 2 is a rear view showing a mirror body portion of FIG.

3A and 3B are diagrams showing a design example of a conventional mirror body, in which FIG. 3A is a front view and FIG. 3B is a plan view of FIG.

4A and 4B are diagrams showing a design example of the mirror body of the first embodiment, wherein FIG. 4A is a rear view and FIG. 4B is a sectional view taken along line AA of FIG.

FIG. 5 is a perspective view showing a configuration of an optical scanner according to a second embodiment.

6 is a perspective view showing an internal configuration of the mirror body of FIG.

FIG. 7 is a perspective view showing a configuration of a conventional optical scanner.

[Explanation of symbols]

 14 Mirror body 16 Mirror (flat plate) 16A Reflecting surface 18 Reinforcing member 20 Swing shaft 24 Round hole (hollow part) 32 Mirror body 34 First reinforcing member (honeycomb structure) 36 Second reinforcing member

Claims (4)

[Claims] 1. A mirror for an optical scanning device, comprising a mirror body having a swing axis parallel to a reflecting surface and swinging in a predetermined angle range about the swing axis, wherein the reflecting surface of the mirror body is A mirror for an optical scanning device, wherein a plurality of hollow portions are provided on the back surface side of the. 2. The mirror body includes a flat plate having the reflecting surface formed on one surface thereof, and a reinforcing member bonded to the flat plate and having a plurality of hollow portions. The mirror for an optical scanning device according to claim 1. 3. The hollow portion is mainly provided at a position away from the swing shaft.
Alternatively, the mirror for an optical scanning device described in 2. 4. The mirror for an optical scanning device according to claim 2, wherein the reinforcing member is a honeycomb structure.