JPH06203198A - Optical scanner - Google Patents

Abstract

PURPOSE:To provide a compact optical scanner of a simple structure which can two-dimensionally scan the light beam by means of a single plane mirror. CONSTITUTION:An optical scanner is provided with a plane mirror 7, a pair of cantilever type vibration arms 8L and 8R which elastically support both ends of the mirror 7 via a flexible coupling part 8a, and a pair of oscillators 10L and 10R which vertically oscillate both arms 8L and 8R independently of each other. Then the arms 8L and 8R are relatively driven in vibrations of different frequencies via the oscillators 10L and 10R. Thus the reflecting surface of the mirror 7 tilts back and forth and right and left in terms of change with time. Thus the light beam 6 projected onto the mirror 7 from a light source 1 and the reflected beam 6 is two-dimensionally scanned on the illuminating surface of a bar code label, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanner applied to a hand scanner of a bar code reader or the like.

[0002]

2. Description of the Related Art Recently, most bar code readers employ a system in which a light beam is two-dimensionally scanned with respect to a bar code label in order to correctly read bar code data regardless of the direction of the bar code label. Has been done.
Here, a conventional optical scanner that two-dimensionally scans a light beam is shown in FIG. In the figure, 1 is a light source such as a laser diode, 2 is a polygon mirror, 2a is a drive motor for the polygon mirror 2, 3 is a polygonal (triangular) prismatic mirror, 3a is a prismatic mirror rotation drive motor, and 4 is a light receiver. 5 is a bar code label to be read.

With this structure, the light beam 6 emitted from the light source 1 toward the polygon mirror 2 is reflected by the reflecting surface of the polygon mirror 2, and then further reflected by the prism mirror 3 to scan the bar code label 5. The reflected light is collected by the light receiver 4. Here, polygon mirror 2 and prism mirror 3
And are rotated about rotation axes orthogonal to each other, and the light reflected by the prismatic mirror 3 is two-dimensionally scanned with respect to the barcode label 5.

[0004]

By the way, in the conventional structure of the above-mentioned two-dimensional scanning type optical scanner, the optical system requires two mirrors and a drive motor for each mirror, which complicates the structure. Moreover, the diameter of the polygon mirror 2 is several tens.
The prismatic mirror 3 which has a size of mm and receives the reflected light from the polygon mirror 2 needs to have a length dimension at least corresponding to the size of the bar code label. For this reason, an optical scanner device incorporating these two mirrors has a large size. Becomes

The present invention has been made in view of the above points, and an object thereof is an optical scanner having a small size, a light weight, and a simple structure in which a light beam is two-dimensionally scanned by using one plane mirror. To provide.

[0006]

In order to achieve the above object, an optical scanner according to the present invention comprises a plane mirror, a pair of cantilever type vibrating arms flexibly supporting both left and right ends of the mirror, and A pair of exciters for individually vibrating the vibrating arms in the vertical direction are provided, and by driving the vibrating arms with different vibrations via the exciters, the light beam projected from the light source to the mirror is projected. The irradiation surface is configured to be two-dimensionally scanned with the reflected light.

Further, as a method for driving the pair of vibrating arms with different vibrations in the above configuration, the following embodiments can be applied. (1) Driving is performed by changing the vibration frequency relatively between the exciters. (2) Driving is performed by changing the amplitude of vibration relatively between the exciters. (3) Driving is performed by changing the phase of vibration between the exciters relatively.

[0008]

When the pair of cantilever type vibrating arms supporting the left and right ends of the plane mirror are driven by the exciter so as to be swung up and down, the vibrating arm is armed with the fixed end on the root side as a fulcrum. The mirror support point at the tip is displaced along an arc whose radius is the arm length. Further, when the vibration exciter is driven with relatively different vibrations with respect to the left and right vibration arms, for example, with different frequencies, a relative vertical displacement difference is generated between the left and right mirror support points in addition to the above-mentioned movement. Join. Therefore, the mirror supported between the pair of left and right vibrating arms has various tilts in the X direction and the Y direction with respect to the virtual X, Y coordinate axes in the front, rear, left, and right on the reflecting surface. It becomes a movement. As a result, the direction of the reflected light of the light beam projected from the light source toward the plane mirror is deflected in accordance with the movement of the mirror, and the reflected light is two-dimensionally reflected on the irradiation surface such as a bar code label. To be scanned. Such movement of the mirror can be performed by changing the vibration frequency of the vibration exciter, or by relatively changing the amplitude and phase of the vibration.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In the figure, the same parts as those in FIG. 5 are designated by the same reference numerals. First, FIG. 1 shows the overall configuration of an optical scanner. In the figure, 7 is a disk-shaped plane mirror, 8L,
Reference numeral 8R is made of an elastic metal material, a base portion of one end of which is cantileveredly fixed to a support body 9, and a pair of vibrating arms in which free ends of arm ends are connected to left and right ends of the mirror 6, and 8a is a vibrating arm A flexible connecting portion formed by zigzag bending at the tip of 8L, 8R, 10L, 10R is a vibrating arm 8L,
A vibration element such as a piezoelectric element or a voice coil disposed opposite to the intermediate portion of 8R, and 11 is a driver of the vibration elements 10L and 10R. The plane mirror 7 is held horizontally between the left and right vibrating arms 8L and 8R in a stationary state.

With such a configuration, the light beam 6 emitted from the light source 1 is projected obliquely from above toward the center of the plane mirror 7, and the reflected light of the mirror 7 irradiates the bar code label 5 (see FIG. 5) and the like. . Here, the left and right shakers 10L, 1
0R is vibrated by the output from the driver 11, and the vibration arm 8
By driving the L and 8R with different vibrations as described below, the reflected light of the mirror 7 is two-dimensionally scanned on the irradiation surface on which the barcode label is placed.

Next, the operation of the above configuration will be described with reference to FIGS. First, FIGS. 2 (a) and 2 (b) are vibration waveform diagrams of the arm tips (supporting points at both ends of the mirror 7) of the vibrating arms 8L and 8R driven by the exciters 10L and 10R.
The vertical axis represents the vertical displacement. In addition, FIG.
FIG. 2 is a diagram showing the movement (posture) of the mirror 7 corresponding to each time t0 to t6 on the time axis of 1 by dividing it into virtual X and Y axis directions on the reflecting surface of the plane mirror 7 in FIG. 1. In FIG. 3, the X-axis direction is a cross-section in the left-right direction that passes through the center of the plane mirror 7 that connects the support points connecting the vibrating arms 8L and 8R, and the Y-axis direction is the right-angled section. The cross section in the front-rear direction passing through the center of is shown.

That is, when the vibrating arms 8L and 8R are driven so as to be swung in the vertical direction by driving the vibrating units 10L and 10R, the vibrating arms 8L and 8R follow this movement.
The connecting point between R and the mirror 7 is displaced along an arc whose radius is the length of the vibrating arm, and this displacement causes the reflecting surface of the plane mirror 7 coupled and supported between the vibrating arms 8L and 8R. It tilts so as to repeat forward and backward tilts with respect to the horizontal plane in the Y-axis direction. Further, in this case, when a relative displacement difference in the height direction is given between the left and right vibrating arms 8L and 8R, the reflecting surface of the mirror 7 corresponds to the relative displacement difference in the X-axis direction with respect to the horizontal plane. Tilt to the left and right (up to the right or up to the left). In this case, the bending and twisting stresses due to the relative displacement difference between the vibrating arms are absorbed by the flexible connecting portion 8a formed at the tip of the arms.

Therefore, the left and right vibrating arms 8L, 8R
On the other hand, as shown in FIGS. 2 (a) and 2 (b), if the vibration frequency is relatively changed and driven by the vibrators 10L and 10R, the reflecting surface of the mirror 7 is moved in the X-axis direction as shown in FIG. The tilt angle in the Y-axis direction changes with time, and the reflection direction and the deflection angle of the reflected light change in accordance with the transition of this tilt movement. here,
With the flat mirror 7 having a diameter of 1 mm and the vibrating arms 8L and 8R having a length of 10 mm in the above-mentioned configuration, the flat mirror 2 is
The scanning locus of the reflected light on the irradiation surface at a distance of 0 mm is shown in FIG. In the figure, the scale numbers are in units of mm, P is the starting point of the scanning locus, and the arrow is the moving direction of the light spot. As is clear from this figure, the scanning locus of the light spot on the irradiation surface is two-dimensional, which allows the bar code data to be accurately recorded even when the direction of the bar code label placed on the irradiation surface is different from the direction of the canner. Can be read.

Incidentally, FIG. 4 shows an example of the scanning locus pattern. By changing the arm lengths of the vibrating arms 8L and 8R and the vibration frequencies of the vibrators 10L and 10R, scanning different from that of FIG. A trajectory pattern is obtained. Also, instead of changing the vibration frequency between the shakers 10L and 10R, the amplitude of the vibration is relatively changed with time, or the phase angle of the vibration is changed, so that the two-dimensional scanning similar to the above is performed. You can do it.

[0015]

As described above, according to the optical scanner of the present invention, one plane mirror can be adopted to two-dimensionally scan the irradiation surface with the reflected light. The structure is simple compared to the structure that combined two mirrors in
Moreover, advantages such as reduction in size and weight of the entire device can be obtained.

[Brief description of drawings]

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

2A and 2B are vibration waveform diagrams by driving the vibrating arm in FIG. 1, where FIG. 2A is a vibration waveform diagram of a pair of left and right vibrating arms, and FIG. 2B is a vibration waveform diagram of the other vibrating arm.

3 is an X-axis of a plane mirror corresponding to the vibration waveform of FIG.
Operation explanatory diagram showing movement over time in the Y-axis direction

FIG. 4 is a diagram showing a scanning trajectory pattern of reflected light corresponding to the movement of the plane mirror in FIG.

FIG. 5 is a schematic configuration diagram of a conventional two-dimensional scanning optical scanner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 light source 5 bar code label 6 light beam 7 plane mirror 8L, 8R vibrating arm 8a flexible connecting portion 9 vibrating arm support 10L, 10R exciter 11 exciter driver

Claims (4)

[Claims] 1. A flat mirror, a pair of cantilever type vibrating arms flexibly supporting both left and right ends of the mirror, and a pair of exciters for individually vibrating the vibrating arms in the vertical direction.
By driving each vibrating arm with different vibrations via the vibrator, the reflected light of the light beam projected from the light source to the mirror is two-dimensionally scanned on the irradiation surface. . 2. The optical scanner according to claim 1, wherein the vibration arm is driven by relatively changing the frequency of vibration between the vibration exciters. 3. The optical scanner according to claim 1, wherein the vibration arm is driven by relatively changing the amplitude of vibration between the vibration exciters. 4. The optical scanner according to claim 1, wherein the vibration arm is driven by relatively changing the phase of vibration between the vibration exciters.