JPH0283520A - Vibrating body support mechanism - Google Patents

Abstract

PURPOSE:To obtain the vibrating body support mechanism of simple structure which suppresses variation in the center of vibration by supporting a vibrating body through a spring member which is curved in a J-shape. CONSTITUTION:A solenoid 18 as the driving source for a vibration shaft is provided at the upper part in a housing 12 and the prismatic vibration shaft 22 is fitted to the driving shaft 20 of the solenoid 18 which extends downward. Then a mirror 24 with a flat reflecting surface is fitted to the intermediate part of the vibration shaft 22. One-end sides of leaf springs 26a and 26b, and 28a and 28b which are curved in the J shape are fitted nearby both upper and lower end parts of the vibration shaft 22, and the other-end sides are fitted to a support body 16. Thus, the leaf springs 26a and 26b, and 28a and 28b are formed in the J shape to put the mirror 24 close to the vibration shaft 22 and a coupling member is omitted to simplify the structure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vibrating body support mechanism. The present invention relates to a vibrating body support mechanism in a type optical deflector, in which the mirror is fixed to a vibrating shaft, and the vibrating shaft is supported via a spring member curved into a single character shape.

[Background of the Invention] In recent years, optical scanners that process two-dimensional information such as images by vibrating or rotating a mirror at high speed have been widely used.

For example, demand is increasing in laser and infrared applications such as computer output microfilm, laser marking, non-contact printing, communications, and military night vision.

The optical scanner is required to have high precision, high reproducibility, and long-term operability, and is also desirably quick in response and low inertia. Among these optical scanners, one type uses a torsion bar type that uses torsion of a thin metal wire, and the other uses a plate spring type that uses the mechanical resonance phenomenon of a spring member to vibrate the mirror sinusoidally and deflect it. Examples include the Taut band method using torsion, and the flexural bipot method in which a mirror is supported by a leaf spring attached to a vibration shaft.

The main parts of an optical scanner that employs the flexural pivot system are shown in Figure 1a. Reference numeral 2 indicates a mirror vibrating body, and this mirror vibrating body 2 is substantially composed of a vibrating shaft 4, a mirror 6, and plate-shaped spring members 4a to 4d. The vibration shaft 4 is made of a long plate, and a mirror 6 is attached to the central portion of the vibration shaft 4 via a connecting member 6a. The plate-shaped spring members 4a, 4b and 4c, 4d cross each other, and one end is attached to the vibration shaft 4, and the other end is attached to the support 8 shown in FIG. 1bSc. in this case,
The intersection position 0 of the plate-shaped spring members 4a, 4b, 4c, and 4d is between the mirror 6, the vibration shaft 4, and the connecting member 6.
It is set so as to match the position of the center of gravity of the movable part 9 including a. This mirror vibrating body 2 is configured to vibrate in the direction of the arrow around the intersection position 0 by a drive mechanism (not shown).

Here, when the length of the plate-shaped spring members 4a to 4d is 1 and the mirror vibrating body 2 is vibrated by a deflection angle of ±θ, the intersection position 0 is given by the following. Therefore, as understood from equation (1), the intersection position 0 is the length l of the plate spring members 4a to 4d.
Furthermore, as the deflection angle θ of the mirror increases, the variation in the intersection position 0 also increases.

By the way, in the mirror vibrating body 2, in order to perform the deflection operation of the light beam incident on the mirror 6 with high precision,
The movable part 9 is attached to the vibration shaft 4 via a connecting member 6a so that the center of gravity of the movable part 9 coincides with the intersection position O of the plate-shaped spring members 4a to 4d. Therefore, the structure is correspondingly more complicated. In addition, in order to ensure a sufficient deflection angle θ of the mirror 6, the lengths of the plate-shaped spring members 4a to 4d must be adjusted! must be made larger, which also causes the inconvenience of increasing the size of the device.

Furthermore, as described above, since the variation in the intersection position 0 of the mirror vibrating body 2 is proportional to the length l of the plate-shaped spring members 4a to 4d, if the length l of the plate-shaped spring members 4a to 4d is increased, the mirror Fluctuations in the crossing position O of the vibrating body 2 become large.

In this case, there is a risk that the wobble of the light beam scanned by the mirror vibrator 2 cannot be ignored, and non-rotational vibrations caused by the movement of the center of gravity will increase, resulting in a limit on the deflection angle θ of the mirror. becomes. On the other hand, if an attempt is made to shorten the plate-shaped spring members 4a to 4d to suppress the fluctuation of the intersection position 0 and ensure a sufficient deflection angle θ of the mirror, excessive stress will be applied to the plate-shaped spring members 4a to 4d, which will shorten the service life. The inconvenience of being short becomes obvious.

[Object of the Invention] The present invention has been made to overcome the above-mentioned disadvantages, and by supporting the vibrating body through a spring member curved in a three-shape, the structure is simple and the center of vibration can be fixed. It is an object of the present invention to provide a vibrating body support mechanism capable of suppressing fluctuations and ensuring a sufficient vibration amplitude.

[Means for Achieving the Object] In order to achieve the above-mentioned object, the present invention has at least two spring members curved in a three-shape shape, intersecting each other approximately at the center thereof, and having one end of each spring member A vibrating body support mechanism, characterized in that the vibrating body is fixed to a support body, and a vibrating body is attached to the other end of each of the spring members, so that the vibrating body is vibrated by the elasticity of the spring members.

[Embodiments] Next, preferred embodiments of the vibrating body support mechanism according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 2, reference numeral 10 indicates a mirror oscillating optical deflector according to this embodiment, and this mirror oscillating optical deflector I
O includes a cylindrical tube-shaped housing 12.

The housing 12 has an opening 14 cut out approximately 180 degrees along the circumference, and a mirror described later is installed inside the housing 12 so as to face this opening 14.

A support body 16 having an arcuate cross section is fixedly provided within the housing 12 .

Further, a solenoid 18 that is a drive source for a vibration shaft, which will be described later, is provided in the upper part of the housing 12. The drive shaft 20 of the solenoid 18 extending downward has a prismatic vibration shaft 22.
is attached. A mirror 24 with a flat reflective surface is attached to the middle part of the vibration shaft 22 so as to face the opening 14 of the housing 12. In this case, the position of the center of gravity of the movable portion 29 composed of the mirror 24, the vibration shaft 22, and the drive shaft 20 is set to coincide with the center of vibration.

One end portions of plate springs 26a, 26b and 28a, 28b curved in a letter-shape are attached near both upper and lower ends of the vibration shaft 22, and the plate springs 26a, 26b and 2
The other ends of 8a and 28b are attached to the support 16.

In this case, the single-shaped leaf springs 26a, 26b and 28a, 28b are arranged to intersect each other at substantially right angles at their central portions. leaf springs 26a, 26b and 28a,
The intersecting position of 28b is arranged to match the position of the center of gravity of the movable part 29.

Here, the single-shaped leaf springs 26h, 26b and 2
The external shapes of 8a and 28b are shown in FIG. In the figure, the leaf springs 26a, 26b, and 28a128b are curved into a substantially J-shape, and are composed of a short piece 30, a long piece 32, and a connecting portion 38 that connects them. Attachment holes 34a and 34b for attachment to the vibration shaft 22 are bored in the end portion 34 of the short piece 30. Further, an attachment hole 36a136b for attaching to the support body 16 is bored in the end portion 36 of the long piece 32.

The mirror vibrating optical deflector according to this embodiment is basically constructed as described above, and its operation and effects will be explained next.

In this case, an example of an image scanning device to which the mirror vibrating optical deflector according to the present embodiment is applied will be described.

First, in order to scan an object to be scanned, such as a document or a record carrier, with a light beam, an alternating current is supplied to the solenoid 18 from the outside, as shown in FIG. In this case, the solenoid 18 causes the drive shaft 20 to swing, thereby causing the mirror 24 attached to the vibration shaft 22 to vibrate.

Therefore, the light beam L incident on the mirror 24 is reflected and deflected by the mirror 24, and is scanned over an object to be scanned, such as a document, through a scanning lens (not shown), and an image is read or recorded.

Here, both ends of the vibration shaft 220 are connected to the support body 1 through letter-shaped plate springs 26a, 26b and 28a, 28b.
It is attached to 6. Then, the single-shaped leaf spring 2
6a, 26b and 28a, 28b are configured to intersect with each other at intersection position 0 shown in FIG.
a, 26b and 28a, 28b resonate, and the mirror 24
vibrates in the direction of the arrow shown in FIG.

In this case, leaf springs 26a, 26b and 28a128b
When the coordinate system is set as shown in FIG. 4 aSb, the intersection position 0 of is given by the following with respect to the deflection angle θ. Here, f is the leaf spring 26a126b,
28a, 28b indicates the length of the long pieces 32, and 12 indicates the length of the short pieces of the leaf springs 26a, 26b, 28a, 28b.

Therefore, in the conventional support mechanism shown in FIG. 1, the intersection position O of the plate-shaped spring members 4a to 4d is
It varies in proportion to the length l of d (see equation (1)).

On the other hand, the mirror vibrating optical deflector 1 according to the present embodiment
0, the intersection position 0 varies in proportion to the difference between the length 11 of the long piece 32 of the leaf springs 26a, 26b and 28a, 28b and the length 12 of the short piece 30, as shown in equation (2). .

Therefore, as in the prior art, the length l of the plate-shaped spring members 4a to 4d necessary to ensure a sufficient deflection angle θ of the mirror,
Leaf springs 26a, 26b, 28a applied to the mirror vibration type optical deflector 10 according to this embodiment.

When considering the length 11 of the long piece 32 of 28b as being equal, it is easily understood that the variation in the intersection position 0 in the mirror vibrating optical deflector lO according to this embodiment is clearly smaller than that in the conventional case. Good morning. On the other hand, the vibration shaft 22 is substantially the short piece 3 of the leaf springs 26a, 26b, 28a, 28b.
Since it is supported by a spring force of length IB + 12), which is the sum of length 0 and long piece 32, the deflection angle is equivalent to the deflection angle obtained by using a straight leaf spring of length (I!1 + fz). You can secure the corner. As a result, extremely highly accurate image reading or recording can be performed while ensuring a sufficient deflection angle θ.

Further, by forming the leaf springs 26a, 26b, 28a, and 28b into a three-shape, the mirror 24 can be brought close to the vibration shaft 22, thereby omitting the conventional connecting member 6a and simplifying the structure. becomes possible. moreover,
Since the casing 12 that houses the mirror 24 can be made smaller, the device can also be made smaller.

Note that the three-shaped leaf springs 26a, 26b, 28a, 28
When b is made of a material with plate thickness: T = 0.5 mm, material: spring steel, Young's modulus: E = 20.000 kg/mm2, mirror 2 centered at intersection position O
The torque characteristic with respect to the deflection angle θ of No. 4 exhibits a linear characteristic as shown in FIG.

In addition, the spring constant near the rotation angle of 0° is k = 0.04 kgcm/dag = 0.225 Nm.
/rad, and there is nonlinearity such that the spring constant k increases as the deflection angle θ increases.

However, within the range of deflection angle θ of ±15°,
The change in spring constant is within a few percent, and although it depends on the application, it can often be considered linear. The leaf springs 26a, 26b, 2ga.

28b, the moment of inertia J = I Xl0-'
When the vibration shaft 22 of "kgm" is supported and resonated, the resonance frequency f is when the deflection angle θ = 0°, f = 1 / 2 yr \, " ■ 10,000 = 151 H
z, and the resonance characteristics are as shown in FIG. in this case,
Although the resonance frequency f changes as the deflection angle θ increases, it has been found that there is no problem in practical use.

[Effects of the Invention] As described above, according to the present invention, a plurality of spring members curved in a 3-shape are crossed, and one end of the spring member is fixed to a support body, while the other end is provided with vibration. A body is attached to the vibrating body, and the vibrating body is configured to vibrate using a resonance phenomenon. In this case, since the vibrating body can be placed at the center of vibration caused by the spring member, its mounting structure becomes extremely simple. Further, by forming the spring member into a three-shape shape, fluctuations in the center of vibration can be suppressed to a sufficiently small level while ensuring the deflection angle of the vibrating body, so that extremely highly accurate vibration characteristics of the vibrating body can be obtained. Therefore, when this mechanism is applied to an optical scanner, it is possible to suppress vibrations other than rotation caused by high-speed rotation, wobble of the mirror, etc., and highly accurate optical scanning becomes possible. Furthermore, the three-shaped spring member exhibits linear torque characteristics with respect to the deflection angle, and the resonance characteristics of the spring member are very sharp, making it possible to perform stable and highly accurate optical scanning. Become.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an optical scanner using a flexinilar pivot system according to the prior art, and FIG. 2 is a perspective view of a main part configuration of a mirror vibrating optical deflector to which a vibrating body support mechanism according to the present invention is applied. , Fig. 3 is an explanatory diagram of the shape of the 1-shaped spring member in Fig. 2, Fig. 4 is an explanatory diagram of the action of the mirror vibration type optical deflector shown in Fig. 2, and Fig. 5 is an explanatory diagram of the mirror shown in Fig. 2. FIG. 6 is a resonance characteristic diagram of the mirror shown in FIG. 2. 10... Mirror vibration type optical deflector 12... Housing 16
... Support body 18 ... Solenoid 2
0... Drive shaft 22... Vibration shaft 24
...Mirrors 26a, 26b, 28a, 28b=-plate spring 30...
Short piece 32...Long piece FIG, 2

Claims (3)

[Claims] (1) At least two spring members curved into a J-shape are crossed at approximately the center of each spring member, one end of each spring member is fixed to a support body, and a vibrating body is attached to the other end of each spring member. A vibrating body support mechanism, characterized in that the vibrating body support mechanism is configured such that the vibrating body is vibrated by the elasticity of a spring member. (2) The vibrating body support mechanism according to claim 1, wherein the vibrating body is a deflection mirror constituting a mirror vibrating optical deflector. (3) The vibrating body support mechanism according to claim 1, wherein the vibrating body is configured to vibrate resonantly by using a resonance phenomenon of the spring member.