JPS63237023A - Optical scanner - Google Patents

Abstract

PURPOSE:To obtain an optical scanner which has a semi-permanent life, is small in size and low in cost by bending both sides of a mirror mounting part of a leaf spring to directions opposite from each other so that both ends of the leaf spring are approximately paralleled and increasing and decreasing the distance between both ends of the leaf spring by an expanding and contracting mechanism thereby rotationally driving a mirror. CONSTITUTION:The mirror 2 for scanning light is mounted to approximately the central part of the leaf spring 1 and both sides of the mirror mounting part of the leaf spring 1 are bent in the directions opposite from each other so that both ends of the leaf spring are approximately paralleled. The expanding and contracting mechanism 3 to increase or decrease the distance between the two ends of the leaf spring 1 is provided so as to generate the motion in the rotating direction in the mirror 2. The leaf spring 1 is deformed and the mirror 2 rotates when compressive force is exerted to both ends of the buckled leaf spring 1 in the direction shown by arrows. The need for providing a sliding part is thereby eliminated and the life is semipermanent since there are no wearing parts. In addition; the scanner is reduced in size and is produced at the lower cost.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an optical scanner for scanning light, and is suitable for scanning laser light or the like.

(Background Art) Conventionally, the following two methods are known as general methods for scanning light. One method is to use a polygon mirror. For example, a 6- to 12-sided polygon mirror (polygon mirror) is rotated by a motor and the direction of reflection of the light irradiated on the mirror surface is changed, thereby scanning the light. This is what we do. This method allows the scanning angle to be increased and provides very good performance, and is widely used.

However, since polygon mirrors are expensive,
Optical scanners using polygon mirrors are generally very expensive. Furthermore, since the polygon mirror is rotationally driven using a motor, there is a limit to its lifespan due to wear of the motor bearings, etc.

Another method is to use a galvanometer mirror,
It scans light using a galvanometer mirror that includes a pair of permanent magnet stator and rotor, and a pair of control coils that control the rotation angle of the rotor. This method is lower in cost than the method using a polygon mirror, but because the galvanometer mirror has a sliding part, its lifespan is not much different from the method using a polygon mirror.

(Object of the invention) The present invention has been made in view of the above points, and
The purpose is to provide an optical scanner that has a semi-permanent life, is small in size, and is low in cost.

(Disclosure of the Invention) In the optical scanner according to the present invention, as shown in the attached drawings, a mirror 2 for scanning light is attached to a substantially central portion of a leaf spring 1, and a mirror 2 for scanning light is attached to both ends of the leaf spring 1. Both sides of the mirror mounting portion of the leaf spring 1 are bent in opposite directions so that the mirrors are substantially parallel, and the distance between both ends of the leaf spring 1 is expanded or contracted so that the mirror 2 moves in the rotational direction. It is equipped with a telescopic fii3 that allows the user to move.

FIG. 1 is a perspective view showing an embodiment of the present invention.

In this embodiment, the mirror 2 is mounted approximately at the center of a leaf spring 1 having the same width as the mirror 2, and both ends of the leaf spring 1 are bent by bending both sides of the mirror mounting part at obtuse angles in opposite directions. The parts are made to be approximately parallel. When a compressive force is applied to both ends of the buckled leaf spring 1 processed in this way in the direction shown by the arrow in FIG. 1, the leaf spring 1 is deformed and the mirror 2 is rotated. FIG. 2 is a diagram for explaining this operation. In FIG. 2, the solid line shows a state in which a displacement of Δy is equally applied from both ends of the leaf spring 1, and the broken line shows a natural state in which the displacement Δy is not applied.

For example, incident light in the form of a spot beam is irradiated approximately at the center of the mirror 2, and in a natural state where no displacement Δy is applied, reflected light is obtained in the direction shown by the broken line in FIG. On the other hand, when the displacement Δy is applied, reflected light in the direction shown by the solid line in FIG. 2 is obtained. This performs light scanning, and the scanning angle changes depending on the displacement Δy. In the example shown in FIG. 2, since the displacement Δy is applied evenly from above and below, the mirror 2 rotates about the mirror center C as an axis.

3(a) and 3(b) are a side view and a front view of another embodiment, in which the width of the leaf spring 1 is made thinner than the width of the mirror 2. The dimensions of each part shown in FIG. For example, the thickness of the leaf spring 1 is t = o, 1 (uncoated), the width b = 1, 6 (+sn+)
, jump distance d between both ends of the leaf spring 1 = 2 (mm), length II in the natural state between both ends of the leaf spring 1 = 22 (
n...], thickness a of mirror 2 = 1 (mm), length 1 =
6 (nn+), width -= 4 (+1), leaf spring 1
When the material of is phosphor bronze, the amount of compressive displacement Δy given to both ends of the leaf spring 1 is 0 and 2 (n+m), respectively.
When this is assumed, the rotation angle θ of the mirror 2 is approximately 9°, and it has been found that this is a practical optical scanner.

In the embodiment, in order to rotate the mirror 2 around the mirror center C, the shape of the leaf spring 1 is vertically symmetrical, and the same amount of compression is applied from both the upper and lower sides. It goes without saying that if it is only necessary, one end of the leaf spring 1 may be fixed and only the other end may be displaced, or the shape of the leaf spring 1 may be shaped like an upper tool.

Next, various methods can be considered as specific means for applying the displacement Δy to the leaf spring 1. For example, an electromagnetic solenoid, a voice coil, a linear motor, etc. can be used, but miniaturization is the easiest. An example of a telescoping mechanism capable of high-speed response is shown in Fig. 4.

The expansion/contraction mechanism 3 shown in the figure is composed of a laminated piezoelectric element 4 that converts an electric signal into an expansion/contraction motion, and a displacement amplification mechanism 5 that magnifies the displacement of the expansion/contraction movement of the laminated piezoelectric element 4. Laminated piezoelectric element 4
is an actuator that utilizes the piezoelectric inverse effect, so by stacking a large number of thin piezoelectric elements and applying an electric field to them, displacement occurs in the stacking direction in proportion to the magnitude of the electric field.

However, the amount of displacement itself of the laminated piezoelectric element 4 is limited to a length of 20
(mm), it is only possible to obtain a displacement of about 10 to 20 μm, so a mechanism for enlarging the displacement is required. The displacement magnifying machine fiM5 shown in FIG. 4 is made of a visible molded product, and includes a substantially U-shaped fixing part 6 that abuts one end of the laminated piezoelectric element 4, and a pair of arms forming an abbreviated letter shape. 7a, 7b, thin fulcrum parts 8a, 8b connecting the fixed part 6 and arms 7a, 7b, and each arm 7a, 7b.
'f?' by connecting the ends near the fulcrum parts 8a and 8b of 'f? It is formed by integrally molding a substantially U-shaped movable part 9 that abuts the other end of the tW1 piezoelectric element 4. When a voltage is applied to the electrodes E, E2 provided on both sides of the laminated piezoelectric element 4 to apply an electric field, the laminated piezoelectric element 4 stretches in the 'ra layer direction, and the movable part 9 is displaced downward in the figure. Therefore, the fulcrum part 8a.

Arms 7a and 7b are displaced in the direction shown by the arrow with 8b as the center. At this time, the displacement of the movable part 9 is magnified by the "lever" principle, and the displacement at the upper ends of the arms 7a, 7b becomes larger.Both ends of the leaf spring 1 are attached to the upper ends of the arms 7a, 7b, respectively. It is fixed, and the arms 7a, 7
By displacing b in the direction indicated by the arrow, the distance between both ends of the leaf spring 1 is compressed.

(Effects of the Invention) As described above, in the present invention, a mirror for scanning light is mounted approximately in the center of a leaf spring, and both sides of the mirror mounting portion of the leaf spring are bent in opposite directions. The two ends of the leaf spring are made substantially parallel, and the mirror is rotated by expanding and contracting the distance between the two ends of the leaf spring using an expansion/contraction Ia mechanism, which makes it possible to drive the mirror rotationally. There is no need to provide sliding parts like in optical scanners, and there are no parts that wear out, so it has the effect of a semi-permanent lifespan.
Further, since the mirror drive R tower can be constructed from a leaf spring processed into a predetermined shape and its extension WJ mechanism, it is possible to manufacture the mirror in a small size and at low cost.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the same operation as above, FIG. 3(a) is a side view of an embodiment of the pond of the present invention, and FIG. The front view and FIG. 1 are perspective views showing an example of the telescoping mechanism used in the present invention. 1 is a leaf spring, 2 is a mirror, and 3 is an expansion/contraction mechanism.

Claims (2)

[Claims] (1) A mirror for scanning light is attached to approximately the center of the leaf spring, and both sides of the mirror-attached portion of the leaf spring are bent in opposite directions so that both ends of the leaf spring are approximately parallel. An optical scanner comprising: an expansion mechanism that expands and contracts the distance between both ends of the leaf spring so that the mirror moves in a rotational direction. (2) The optical scanner according to claim 1, wherein the expansion/contraction mechanism includes a laminated piezoelectric element that generates displacement in response to an electric signal, and a displacement amplification mechanism that magnifies the displacement of the laminated piezoelectric element. .