JPH0628509A - Multipattern optical scanning device - Google Patents

Abstract

PURPOSE:To miniaturize and lighten a multipattern optical scanning device. CONSTITUTION:The multipattern optical scanning device scans a light beam in multiple directions and generates multiple patterns. A polygon mirror 6 generating plane scan light beams 63 and 64 deflected by one or plural planes is provided. Plane scan light beams 63 and 64 are bent/reflected by a first mirror member 1 and a second mirror member 2 and the multiple patterns are projected on a screen. The first mirror member 1 has a rotary axis 5 following the direction of the screen and it is provided with a reflecting surface which is almost parallel to the rotary axis 5. Then, the first mirror member turns around the rotary axis 5. On the other hand, the second mirror member 2 turns the outer periphery of the first mirror member 1 in the same direction at angular velocity twice as much as that of the first mirror member 1 and it is provided with a reflecting surface arranged at an angle with which the plane scan light beams 63 and 64 reflected by the first mirror member 1 are deflected in the direction of the screen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-pattern optical scanning device for scanning an incident light beam in multiple directions to generate a multi-pattern. More specifically, it relates to a technique for rotating a raster pattern of plane scanning light formed by a polygon mirror or the like in multiple directions to generate a multi pattern. Such a multi-pattern optical scanning device is incorporated in, for example, a bar code reader or the like and used for optically reading a bar code attached to an article.

[0002]

2. Description of the Related Art A method of generating a multi-pattern using a polygon mirror is disclosed in, for example, US Pat. No. 3,889,102, and its outline is shown in FIG. The polygon mirror PM has a reflective multifacet having different inclination angles with respect to the rotation axis R, and reflects incident light from the laser diode LD to generate a so-called raster pattern. The light reflected from one reflecting surface is angularly deflected along a plane and becomes so-called plane scan light PS. An image inverting element or image rotating element DP called a Dove prism is arranged in the emitting direction of the polygon mirror. In addition to the Dove prism, a Pechan prism, a Porro prism, or an element in which the above Dove prism is configured by a mirror can be used as the image rotating element. As indicated by the arrow, the image rotator DP is rotating, and the incident plane scan light P
It has the function of rotating S by refracting and internally reflecting S. For example, when the image rotation element DP rotates by θ, the fixed scan line SL formed by the plane scan light PS rotates by 2θ and is enlarged and projected on the screen SC.
The projected scan line PSL rotates with the rotation of the image rotation element DP. That is, the static raster pattern composed of a plurality of scan lines SL is rotated in multiple directions to obtain a multi pattern composed of innumerable projection scan lines PSL.

[0003]

Since the image rotator rotates relative to each other when the plane scan light passes through the inside, the optical axis sectional area of the image rotator has the maximum scan angle of the plane scan light as the solid angle. It should be large enough to contain the cone. Therefore, if you set the scan angle of the incident plane scan light and the cross-sectional area of the return light beam from the target to a practical level,
There is a problem in that the size of the image rotation element becomes abnormally large and it is difficult to reduce the size and weight of the apparatus.

[0004]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, it is an object of the present invention to reduce the size and weight of a multi-pattern optical scanning device. The following measures have been taken in order to achieve this object. That is, a multi-pattern optical scanning device that scans light rays in multiple directions to generate a multi-pattern includes, as a basic component, a line scanning unit that generates a plane scan light deflected in one or a plurality of planes. There is. As a feature of the present invention, a first mirror member having a rotation axis along a target direction and having a reflecting surface substantially parallel to the rotation axis and rotating around the rotation axis; and the first mirror member. Arranged at an angle such that the outer periphery of the first mirror member is rotated in the same direction at an angular velocity that is twice the angular velocity of the member, and the plane scan light reflected by the first mirror member is deflected toward the target. And a second mirror member having a reflected surface. Further, a first driving means for rotating the first mirror member around the rotation axis and a second driving means for rotating the second mirror member around the first mirror member are provided. There is. With this configuration, the plane scan light is rotated around the rotation axis to obtain a multi-pattern.

Preferably, each of the first mirror member and the second mirror member is composed of one plane mirror. Alternatively, the first mirror member is composed of one roof mirror and the second mirror member is composed of one plane mirror. Alternatively, the first mirror member may be composed of one plane mirror, and the second mirror member may be composed of a plurality of plane mirrors angularly arranged around the rotation axis along the circumferential direction.

More preferably, the first mirror member is a multi-sided inner mirror member having N reflecting surfaces substantially parallel to the rotation axis, and the second mirror member is a reflection surface of the multi-sided inner mirror member. It is composed of a multi-faced outer mirror member having M reflecting surfaces arranged at equal intervals in the circumferential direction at an angle such that the plane scan light reflected by the surface is deflected toward the target. For example, the polyhedral inner mirror member has N = 4 reflecting surfaces arranged at 90 ° intervals, and the polyhedral outer mirror member has M = 2 reflecting surfaces arranged at 180 ° intervals.

[0007]

According to the present invention, the static raster pattern generated by the line scanning means is rotated by the combination of the first mirror member and the second mirror member to obtain a multi-pattern. The first mirror member can be composed of, for example, a single rotating plane mirror having an area sufficient to reflect a stationary raster pattern, and can be made compact and lightweight. Further, the second mirror member is rotationally driven so as to be aligned with the reflection direction of the first mirror member, and it is sufficient that the second mirror member also has an area sufficient to reflect the raster pattern, and it is possible to reduce the size and weight. .

If the first mirror member is composed of a single rotating flat mirror, a rotating area where the reflection of the raster pattern is impossible, that is, a dead zone occurs. In order to remove this dead zone, the first mirror member may be composed of an inner mirror member made of a rotating polyhedron. In this case, the second mirror member also needs to be divided and arranged along the circumferential direction.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic sectional view showing a first embodiment of a multi-pattern optical scanning device according to the present invention. As shown in the figure, this apparatus is provided with a polygon mirror 6 which is driven to rotate, and constitutes a line scanning means for generating plane scanning lights 63 and 64 which are deflected in a plurality of planes. The polygon mirror 6 has a plurality of reflecting surfaces having different inclination angles. Therefore, the plurality of plane scan lights 63, 64, etc. are deflected so as to have different scan angles. Further, the first mirror member 1 and the second mirror member 2 are provided. In this example, the first mirror member 1
Consists of one plane mirror. The first mirror member 1 is
The rotary shaft 5 has a rotary shaft 5 along the direction of the target or screen, and is provided with a reflecting surface substantially parallel to the rotary shaft 5.
Rotate around. On the other hand, the second mirror member 2 is also composed of a single plane mirror, and rotates the outer periphery of the first mirror member 1 in the same direction at an angular velocity twice that of the first mirror member 1. The second mirror member 2 has a reflecting surface arranged at an angle such that the plane scan lights 63 and 64 reflected by the first mirror member 1 are deflected toward the screen.

The first mirror member 1 is connected to the first driving means 3 via a shaft 31 and is rotationally driven or rotationally vibrated. The second mirror member 2 is rotated around the first mirror member 1 by the second driving means. In this example, the second drive means is the train wheel gears 41, 4
It is composed of 2 and 43. The gear 41 is attached to the shaft 31 of the driving body 3 including a pulse motor or the like, and is connected to the third gear 43 via the idling gear 42 having the pin 46 as an axis. The gear 43 is arranged around the shaft 31 via a bearing 45.
The second mirror member 2 is fixedly supported via a mounting member 44 provided on the surface of the gear 43. The gear ratio of the train wheel is set so that when the motor shaft 31 rotates, the third gear 43 rotates in the same direction at a double angular velocity. Although the first mirror member 1 and the second mirror member 2 are coaxially rotated around the motor shaft 31 in this example, the invention is not necessarily limited to this. Even if it is not coaxial, the relative angular relationship between the first mirror member 1 and the second mirror member 2 may be maintained.

FIG. 2 shows a planar structure of the multi-pattern optical scanning device shown in FIG. The light beam 62 emitted from the laser light source 61 is angularly deflected by the polygon mirror 6 to form plane scan light 63. The "planar scanning light" is a term defined for convenience, and does not necessarily have to be a perfect plane and may be a curved surface. The reflection surface of the first mirror member 1 is attached in a posture substantially parallel to the rotation axis 5 (perpendicular to the paper surface). The plane scanning light 63 is bent and reflected by the first mirror member 1 and the second mirror member 2, and projects a scan line 65 on a screen (not shown) placed perpendicular to the rotation axis 5. In addition, again in FIG.
Referring to, the plane scanning light 64 deflected by the other reflecting surface of the polygon mirror 6 is also projected on the screen in parallel with the above-mentioned scan line 65. First mirror member 1
Is rotated by an angle θ, the reflected plane scan light 6
Although 3 rotates by the angle 2θ, the second mirror member 2 also rotates by 2θ at the same time, so that the relative angular relationship between the reflected plane scan light 63 and the second mirror member 2 is always kept constant. As a result, the scan line 65 projected on the screen rotates around the rotation axis 5 as the second mirror member 2 rotates. In this way, by rotating the second mirror member 2 at an angular velocity twice that of the first mirror member 1, relative rotation is generated between the plane scan light 63 incident on the second mirror member 2. do not do. Therefore, the second mirror member 2 may be provided with a reflecting surface having a dimension in one dimension sufficient to cover the scan angle and an area sufficient to cover the return light from the target or screen. In the example shown in FIG. 2, the plane scan light 63
Is deflected in parallel to the paper surface, but the same is true even if a plane scan light perpendicular to the paper surface is used instead.

FIG. 3 shows an example of the multi-pattern projected on the screen. As described above, the raster pattern formed by the plurality of plane scan lights formed by the polygon mirror 6 is rotated by the first mirror member 1 and the second mirror member 2 to obtain a multi-directional multi-pattern.

FIG. 4 shows the effective rotation area of the first mirror member. As shown in the figure, the first mirror member 1 has a purpose of -45.
It has practicality in the range of ° to + 45 °, and if it exceeds this range, the first mirror member 1 cannot cover the plane scan light 63, and the effective light receiving area of the return light also decreases. That is, at the position 11A where the reflection surface of the first mirror member is shown by the solid line.
From 90 to the position 11B indicated by the dotted line is a practical range. Within this rotation angle, the second mirror member rotates ± 90 ° from the position 2A shown by the solid line to the position 2B shown by the dotted line, so that the scan pattern is 65A to 65B.
It is possible to rotate by 80 ° and cover all directions.

However, when the first mirror member is continuously rotated in a fixed direction, the remaining 27 excluding the effective angle region of 90 °.
0 ° minute is a dead zone. Therefore, when the first mirror member is continuously rotated in a fixed direction, a dead time of 3/4 cycle occurs in one cycle.
In order to remove this dead time, it is preferable that the first mirror member is reciprocally rotated within a range of ± 45 ° to perform vibration drive. By using both surfaces of the first mirror member as reflecting surfaces, it is possible to add a practical area for 90 °.

FIG. 5 shows a modification of the embodiment shown in FIG. Parts corresponding to those of the embodiment shown in FIG. 1 are designated by corresponding reference numerals to facilitate understanding. In this example, the positional relationship among the first mirror member 1, the second mirror member 2, and the plane scan light 63 among the three is different from that of the embodiment shown in FIG. 1, but basically the same principle is used for driving. To do.

FIG. 6 shows still another modification, in which parts corresponding to those of the embodiment of FIG. 1 are designated by corresponding reference numerals to facilitate understanding. In this example, the first mirror member 1 is composed of a roof mirror.

FIG. 7 is a schematic plan view showing a second embodiment of the multi-pattern optical scanning device according to the present invention. The shape is viewed from the end of the rotation axis. In the present embodiment, the second mirror members are mutually rotated about the rotation axis 5 by 90 degrees.
It is composed of two plane mirrors 201 and 202 arranged apart from each other. Both of them rotate together at an angular velocity twice that of the first mirror member 1. One scan light portion 6 obtained when the plane scan light 63 is divided by the center line
After being reflected by the first mirror member 1, reference numeral 31 is bent by one of the plane mirrors 201 and projects a scan line 651 on a screen placed perpendicular to the rotation axis 5. Similarly, the scan light component 632 corresponding to the other half forms another scan line 652 which is orthogonal to the above-mentioned scan line 651. When the first mirror member 1 and the second mirror member 2 rotate, the scan lines 651 and 652 rotate around the rotation axis 5. In this embodiment, the raster pattern is composed of 90 ° intersection lines. Therefore, all directions can be covered by rotating the entire raster pattern by 90 °. Therefore, the pulse motor may be provided with a ± 22.5 ° reciprocating rotary drive. In this example, the two plane mirrors 201 and 202 compose the second mirror member, but it is possible to divide the second mirror member further. Further, by dividing the first mirror member 1 at the same time, it is possible to generate more diverse multi-patterns.

Incidentally, there are cases in which rotational vibration driving is not preferable from a practical point of view in terms of durability, heat generation of a driving source, vibration and the like. Therefore, FIG. 8 shows a third embodiment in which dead time does not occur in continuous rotation driving. The inner mirror member 1 rotating about the rotation axis 5 has a quadrangular prism shape, and has four reflection surfaces 101, 102, 103 and 1 parallel to the rotation axis 5.
04, and is attached to the shaft 31 of the motor 3. On the other hand, the outer mirror member 2 includes two reflecting surfaces 201, 201 which are arranged 180 ° apart from each other about the rotation axis 5.
02, which is attached to the turntable 44 and has a bearing 45.
To rotate around the shaft 31. Shaft 31
The outer mirror member 2 is rotated around the rotary shaft 5 in the same direction at twice the angular velocity of the inner mirror member 1 by the gear 41 fixed to the idler gear 42 having the shaft 46 and the gear 43 provided on the rotary base 44. Rotate. Incident light from a laser light source (not shown) is deflected by the polygon mirror 6 rotating at high speed to become plane scan light 63, for example, on the first reflecting surface 101 of the inner mirror member 1 and the first reflecting surface 201 of the outer mirror member 2. It is reflected and folded and projected in the direction of the screen. The plane scanning light 64 deflected by the other reflecting surface of the polygon mirror 6 similarly goes to the screen.

FIG. 9 shows a plan view of the third embodiment shown in FIG. 8 as seen from the end of the rotary shaft. The light beam 62 emitted from the laser light source 61 is deflected by the polygon mirror 6 to form plane scan light 63. The plane scanning light 63 is reflected by the reflecting surface of the inner mirror member 1 having a rectangular prism shape, then is bent in the axial direction by the reflecting surface 201 of the outer mirror member 2, and is reflected by a screen placed perpendicular to the rotation axis 5. The scan line 65 is projected. When the inner mirror member 1 rotates by an angle θ, the reflected scan light 63 rotates 2θ, but at the same time, the outer mirror member 2 also rotates 2θ, so that the relative angular relationship between the scan light 63 and the outer mirror member 2 always changes. As a result, the scan line 65 rotates around the rotation axis 5 as the outer mirror member 2 rotates.

Finally, the operation of the third embodiment will be described in detail with reference to FIGS. In the case of the positional relationship shown in FIG. 10, the reflecting surface 101 of the inner mirror member 1,
104 is 4 with respect to the center line of the plane scan light 63.
It is inclined by 5 °. At this time, scan lines 651 and 654 are projected on the screen, respectively. The lengths of these scan lines are each halved because the plane scan light 63 is divided into two. Also, scan lines 651 and 6
Both 54 are parallel to the center line of the plane scan light 63.

FIG. 11 shows the reflecting surface 10 of the inner mirror member.
1 represents a state in which it is angularly displaced by 22.5 ° from the position shown in FIG. 10 in the direction of the arrow. At this time, the other reflecting surface 104 can no longer cover the plane scanning light. On the other hand, the reflecting surface 201 of the outer mirror member rotates by 45 ° to form a full scan line 651.

FIG. 12 shows the case where the inner mirror member is displaced by 95 ° from the state of FIG. 10 as the rotation further progresses. The scan line 651 formed by the reflection surface 101 and the reflection surface 201 becomes half or less of the length of the full scan line, and disappears when the angular displacement further progresses. On the other hand, the reflective surface 10
The length of the scan line 652 formed by 2 and the reflecting surface 202 is more than half the length of the full scan line, and reaches the length of the full scan line when the angular displacement further proceeds.

As described above, the scan line is generated over the entire range of the rotation cycle of the inner mirror member 1, and the dead time can be eliminated. In the state shown in FIG. 10, the scan line length is reduced to half, but there is no problem in practical use. Rather, the advantage is that the number of scan lines is doubled. In addition, the rotation angular velocity of the multi-pattern is 1
When set to 80 ° / 50 ms, the rotation speed of the outer mirror member is 600 rpm, and the rotation speed of the inner mirror member is 30 rpm.
It will be 0 rpm. Further, the polygon mirror rotates at 4000 rpm when it has an octagonal facet, for example.
Eight scan lines can be formed per rotation. In particular,
In the state shown in FIG. 10, the number increases to 16.

[0024]

As described above, according to the present invention, there is provided a first rotary shaft having a rotary shaft extending in the direction of the target and having a reflecting surface substantially parallel to the rotary shaft. And the outer peripheral surface of the first mirror member is rotated in the same direction at an angular velocity that is twice the angular velocity of the first mirror member, and the plane scan light reflected by the first mirror member is the target. It has a configuration in which a second mirror member having a reflecting surface arranged at an angle so as to be deflected in a direction is combined. By rotating the second mirror member at an angular velocity twice as fast as that of the first mirror member, relative rotation does not occur between the plane scan light incident on the second mirror member. Therefore, a mirror member having a dimension in the one-dimensional direction sufficient to cover the scan angle and an area sufficient to cover the return light from the target is sufficient, and the structure using the conventional image rotation element is sufficient. In comparison, there is an effect that the size and weight of the device can be remarkably reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a multi-pattern optical scanning device according to the present invention.

FIG. 2 is also a plan view of the first embodiment.

FIG. 3 is a schematic view showing a multi-pattern drawn by the first embodiment.

FIG. 4 is a schematic diagram for explaining the operation of the first embodiment.

FIG. 5 is a schematic diagram showing a modified example of the first embodiment.

FIG. 6 is a schematic view showing another modification of the first embodiment.

FIG. 7 is a plan view showing a second embodiment of a multi-pattern optical scanning device according to the present invention.

FIG. 8 is a sectional view showing a third embodiment of a multi-pattern optical scanning device according to the present invention.

FIG. 9 is likewise a plan view of the third embodiment.

FIG. 10 is an operation explanatory diagram of the third embodiment.

FIG. 11 is an explanatory diagram of an operation of the third embodiment.

FIG. 12 is an explanatory diagram of an operation of the third embodiment.

FIG. 13 is a perspective view showing a conventional multi-pattern optical scanning device.

[Explanation of symbols]

 1 First Mirror Member 2 Second Mirror Member 3 Motor 5 Rotating Shaft 6 Polygon Mirror 31 Shaft 41 Gear 42 Idling Gear 43 Gear 45 Bearing 61 Laser Light Source 63 Planar Scan Light 64 Planar Scan Light 65 Scan Line

Claims (6)

[Claims] 1. A multi-pattern optical scanning device for scanning a light beam in multiple directions to generate a multi-pattern, a line scanning means for generating a plane scanning light deflected in one or a plurality of planes, and a line scanning means in the direction of a target. A first mirror member having a reflecting axis parallel to the rotary axis and rotating about the rotary axis; and a same direction at an angular velocity twice the angular velocity of the first mirror member. A second mirror having a reflecting surface arranged at an angle such that the outer periphery of the first mirror member is rotated and the plane scan light reflected by the first mirror member is deflected toward the target. A member, first driving means for rotating the first mirror member around the rotation axis, and second driving means for rotating the second mirror member around the first mirror member. Becomes the plane A multi-pattern optical scanning device characterized by rotating scan light around a rotation axis to obtain a multi-pattern. 2. The multi-pattern optical scanning device according to claim 1, wherein each of the first mirror member and the second mirror member comprises a single plane mirror. 3. The multi-pattern optical scanning device according to claim 1, wherein the first mirror member comprises one roof mirror and the second mirror member comprises one plane mirror. 4. The first mirror member is composed of one plane mirror, and the second mirror member is composed of a plurality of plane mirrors angularly arranged around the rotation axis along the circumferential direction. The multi-pattern optical scanning device according to claim 1, which is characterized in that. 5. The first mirror member is a multi-faced inner mirror member having N reflecting surfaces substantially parallel to the rotation axis, and the second mirror member is reflected by each reflecting face of the multi-faced inner mirror member. 2. A multi-faced outer mirror member having M reflecting surfaces arranged at equal intervals in a circumferential direction at an angle such that the flattened scan light thus generated is deflected toward a target. The described multi-pattern optical scanning device. 6. The polyhedral inner mirror member has N = 4 reflecting surfaces arranged at 90 ° intervals, and the polyhedral outer mirror member has M = 2 reflecting surfaces arranged at 180 ° intervals. The multi-pattern optical scanning device according to claim 5.