JPH05323225A - Rotary polygon mirror - Google Patents

Abstract

PURPOSE:To improve the mass-productivity of a rotary polygon mirror, which is used for a bar code reader to make a scan with beam light and improve the durability of its reflecting surfaces. CONSTITUTION:The rotary polygon mirror is formed by removing the part of a frustum 1B of regular polygonal cone having a regular polygonal base surface, which is similar to and concentric with the regular polygon of the base surface of a regular polygonal prism 1A made of a transparent body, from the regular prism 1A and has plural reflecting surfaces 12 (12a, 12b, 12c...) consisting of total reflecting surfaces formed into slanting internal surfaces on the external surfaces 14a-14c of the prism 1A. Further, the respective surfaces forming the transparent body are convexly or concavely curved to provide the function of an optical lens for converging or diverging the light beam or making an equal-speed linear scan with the light beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary polygon mirror used for scanning a light beam in a bar code reader or the like.

[0002]

2. Description of the Related Art FIG. 6 is a perspective view showing the structure of a conventional light beam scanner using a rotary polygon mirror. In FIG. 6, the rotary polygon mirror 1 is formed of a regular polygonal prism,
Each side surface is provided with a plurality of reflecting surfaces 11 (11a, 11b, 11c, 11d ---) arranged rotationally symmetrically with respect to the axis 2 of the regular polygonal column.

The light source 3 is a laser diode 3a and a condenser lens.
The light beam 4 from the light source 3 is obliquely projected onto one of the reflecting surfaces 11 of the rotating polygon mirror 1, for example, the reflecting surface 11a, and is reflected by the reflecting surface 11a to illuminate the target area 5. To do. Since the rotary polygon mirror 1 is rotated in the direction of arrow P about the axis (hereinafter referred to as the rotation axis) 2 of the regular polygonal column by a driving device (not shown), the reflecting surface 11 is formed by 11a, 11b, 11b.
The light beam 4 is replaced with the target area 5 each time.
In the direction of arrow Q. That is, the target area 5 is scanned.

This type of light beam scanner is used in, for example, a bar code reader, and in this case, the target area 5 is a label attached to an article or a bar code directly printed on the article surface, and the light beam 4 is used. The reflected light is received by a light receiving device (not shown), photoelectrically converted, and the bar code information is read.

[0005]

The above-mentioned rotary polygon mirror is
For example, aluminum is cut into a regular polygonal column, and each side surface is precision finished to form a reflecting surface.However, this precision finishing is performed by machining, which makes mass production difficult and costly. It was On the other hand, a method has been developed in which a regular polygonal prism is manufactured by resin molding, and the side surface of the regular polygonal pillar is finished by metal vapor deposition or plating to form a reflective surface. There is a problem that metal vapor deposition or plating is susceptible to defects such as peeling, discoloration, and cracks under the influence of ambient temperature and humidity.

Further, the action of the above-mentioned rotary polygon mirror is only for the conformal scanning of the light beam, and the action of converging or diverging the light beam or the constant velocity linear scanning of the light beam required for a laser beam printer or the like is as follows. Since it was entrusted to an independent optical lens different from the above-mentioned rotating polygon mirror, it was difficult to reduce the weight and cost of the applied device. The present invention has been made in view of the above points, and an object thereof is to solve the above-mentioned problems, and to provide a rotary polygon mirror which has mass productivity and has improved durability of its reflecting surface. ..

[0007]

In order to achieve the above object, in the present invention, a rotary polygon mirror having a plurality of reflecting surfaces which are rotationally symmetrical with respect to a rotation axis is provided. It is assumed to be a total reflection surface formed on the inner surface of a polygonal tubular transparent body. In addition, the rotary polygon mirror having the above-mentioned configuration is constructed such that a plurality of reflecting surfaces are formed from a cylindrical transparent body having a regular polygonal shape, and have a bottom surface having a shape similar to the bottom surface of the regular polygonal cylinder and concentric with corresponding diagonal lines. The polygonal frustum is removed to form a first total reflection surface formed on each inner side surface inclined with respect to the outer side surface of the regular polygonal cylindrical body.

In the rotary polygon mirror having the above-mentioned structure, a plurality of reflecting surfaces are formed from a cylindrical transparent body having a regular polygonal shape, and a bottom surface of the regular polygonal cylinder having a similar shape and concentric corresponding diagonal lines. A portion of a regular polygonal frustum having a top surface of the regular polygonal cylinder, and a portion of an inverse regular polygonal frustum having a top surface that is similar in shape and concentric with the corresponding diagonal line, and is formed by removing It is assumed that the regular polygonal cylindrical body is composed of first and second total reflection surfaces formed on respective inner side surfaces inclined with respect to the outer side surface.

Further, in the rotary polygon mirror having the above structure, at least one of the first and second total reflection surfaces of the total reflection surface formed on each inner side surface forming the transparent body is replaced with a flat surface. It has a curved surface shape, and this curved surface has a regular polygonal frustum whose bottom surface is a plane in which each side of the regular polygon is convex or concave with respect to the center of the regular polygon, or the curved plane is an upper surface. It is assumed that the curved surface is formed by removing the inverted regular polygon frustum.

In the rotary polygon mirror having the above structure, the outer surface forming the transparent body has a curved surface shape instead of a flat surface,
This curved surface is assumed to be a curved surface formed by the outer surface of a cylindrical body whose bottom surface is a plane in which each side of the regular polygon is convex or concave with respect to the center of the regular polygon. Further, in the rotary polygon mirror having the above-mentioned configuration, the total reflection surface formed on each inner side surface forming the transparent body is at least the first or second
It is assumed that any one of the total reflection surfaces has a curved surface shape instead of a flat surface, and this curved surface has a curved surface of either a peak or a valley on the outer side with respect to the rotation axis.

In the rotary polygon mirror having the above structure, the outer surface forming the transparent body has a curved surface shape instead of a flat surface,
This curved surface has a curved surface of either a peak or a valley on the outer side with respect to the rotation axis.

[0012]

With the above structure, the rotary polygon mirror of the present invention has a reflecting surface which is a total reflection surface formed on the inner surface of the rotary polygon mirror made of a transparent body, and therefore, the rotary polygon mirror of the conventional rotary polygon mirror. The reflective surface does not come into direct contact with the outside world and is always maintained in a stable state, improving its durability. Further, since this transparent body can be manufactured by molding a transparent resin, for example, it is suitable for mass production.

Further, with respect to the rotary polygon mirror having the above structure,
By adding a convex or concave curved surface to each surface forming the transparent body as needed, not only the conformal scanning of the light beam but also the converging / diverging of the light beam, and further the constant velocity straight line of the light beam Allows scanning.

[0014]

1 shows an embodiment of a light beam scanner using a rotating polygon mirror according to the present invention. FIG. 1 (a) is a perspective view and FIG.
A cross-sectional view of the main part is shown in (b). FIG. 2 shows another embodiment of a light beam scanner using a rotating polygon mirror according to the present invention.
FIG. 2 (a) is a perspective view, and FIG. 2 (b) is a sectional view of a main part. 3 to 5
[Fig. 6] is still another embodiment of the rotary polygon mirror, and is an explanatory diagram that defines the concavo-convex relationship when the surface of the rotary polygon mirror has a curved surface shape instead of a flat surface. FIG. 5 shows a concave curved surface, and the same members corresponding to those in FIG. 6 are designated by the same reference numerals.

In FIG. 1, the rotary polygon mirror 1 is made of transparent resin,
For example, from a regular polygonal cylinder 1A made of a transparent material such as PMMA (polymethylmethacrylate), PC (polycarbonate), or glass, to the regular polygonal cylinder
The portion of a regular polygonal truncated pyramid 1B having a regular polygonal bottom face that is similar to the bottom face of 1A and is concentric and has corresponding diagonal lines is removed. Then, the portion of this regular polygonal truncated pyramid 1B is removed and formed, and the total reflection surface formed on each inner side surface inclined with respect to the outer side surface 14 of the regular polygonal cylinder 1A is the first reflection surface 12.
(12a, 12b, 12c ---) are formed.

A light beam 4 from a light source 3 is projected downward from above the rotary polygon mirror 1, and the light beam 4 enters the inside from the upper end of the rotary polygon mirror 1 made of a transparent body and undergoes total reflection. The reflected light is reflected by the reflecting surface 12 (reflecting surface 12a in FIG. 1), and is emitted from the outer surface 14a of the rotary polygon mirror 1 to illuminate the target area 5. Other operations are similar to those of the conventional rotary polygon mirror shown in FIG.

FIG. 2 shows another embodiment of the light beam scanner using the rotating polygon mirror of the present invention. FIG. 2 (a) is a perspective view and FIG.
A cross-sectional view of the main part is shown in (b). In FIG. 2, from a transparent regular polygonal cylinder 1A, a portion of a regular polygonal truncated pyramid 1B having a regular polygonal bottom face similar to the bottom face of the regular polygonal cylinder 1A and concentric with corresponding diagonal lines. The upper surface of the regular polygonal cylindrical body 1A and the portion of the regular polygonal truncated pyramid 1C having a similar polygonal upper surface of a regular polygon whose concentric corresponding diagonal lines coincide with each other are excluded. Then, the portion of the regular polygonal truncated pyramid 1B is removed, and the total reflection surface formed on each inner side surface inclined with respect to the outer side surface 14 of the cylindrical body 1A is the first reflection surface 12 (12a, 12b, 12c ---) is formed. Further, the total reflection surface formed on the inner side surfaces inclined with respect to the outer side surface 14 of the cylindrical body 1A is formed by removing the portion of the inverted regular polygonal truncated pyramid 1C and the second reflection surface 13 (13a, 13b). , 13c ---)
Is formed.

In the embodiment shown in FIG. 2, the light beam 4 from the light source 3 is projected from the outer surface 14 of the rotating polygon mirror 1, and the light beam 4 is emitted from the outer surface 14a of the rotating polygon mirror 1 made of a transparent material. The first reflecting surface 12 (FIG.
Then, the light is reflected by the reflection surface 12a), turned upward, and then reflected by the second reflection surface 13a, which is a total reflection surface,
The light is emitted from the outer surface 14a of the rotary polygon mirror 1 to irradiate the target area 5. Other operations are similar to those of the rotary polygon mirror of the present invention shown in FIG.

FIGS. 3 to 5 show still another embodiment of the rotating polygon mirror, which is a reflecting surface (12 or 13 or both) which is formed on the rotating polygon mirror and which is a total reflection surface of the light beam 4. It is explanatory drawing explaining the unevenness | corrugation relationship when the side surface (14) of the rotary polygonal mirror 1 which consists of a transparent body in the light transmission path | route has comprised the curved surface shape instead of the flat surface. The shapes are shown in FIG. 5, respectively.

FIGS. 3 (a) and 4 (a) are bottom views of the rotary polygon mirror 1 as seen from below. The polygonal cylinder 1A of the rotary polygonal mirror 1 or the regular polygonal frustums 1B, 1C are shown. Figure 3 (b), (c), Figure 4 (d), showing the case where each side of the regular polygon forms a convex outward with respect to the center of the regular polygon. (e) shows a cross-sectional view taken along arrow AB of each example. 3 (b) and 4 (d) show another embodiment corresponding to FIG. 1, and FIGS. 3 (c) and 4 (e) show another embodiment corresponding to FIG.

In the embodiment of FIGS. 3B and 3C, the reflecting surfaces 22 (22a, 22b) corresponding to the first reflecting surface 12 of the rotary polygon mirror 1 of FIG.
---), or the first and second reflecting surfaces of the rotary polygon mirror 1 in FIG.
Reflective surfaces 22 (22a, 22b ---), 23 (23a, 23b--) corresponding to 12 and 13
-) Forms a curved surface instead of a flat surface, and this curved surface is a regular polygonal frustum whose bottom surface is a plane in which each side of the regular polygon is convexly curved with respect to the center of the regular polygon from the regular polygonal cylinder 1A. Or a curved surface formed by removing the inverted regular polygonal frustum having the curved plane as an upper surface. In addition, the side surface 24 (2) of the regular polygonal cylinder corresponding to the side surface 14 of the regular polygonal cylinder 1A of the rotary polygon mirror 1 of FIGS.
4a, 24b ---) forms a curved surface instead of a flat surface, and this curved surface is formed from the outer surface of a cylinder whose bottom surface is a plane in which each side of the regular polygon is convexly curved with respect to the center of the regular polygon. It is a curved surface that is formed. That is, there is no bending in the direction of the rotation axis, and the shape is convex outward with respect to the rotation axis 2.

In the embodiment shown in FIGS. 4 (d) and 4 (e), the reflecting surfaces 32 (32a, 32a, 32a, 32a, 32a, 32a, 32b corresponding to the first or second reflecting surfaces 12, 13 of the rotary polygon mirror 1 of FIG. 1 or 2 are used. 32b ---) and 33 (33a, 33b ---) form a curved surface instead of a flat surface, and the curved surface has a mountain-shaped curved surface on the outer side with respect to the rotation axis. Further, the side surface 34 (34a, 34b ---) of the regular polygonal tube body corresponding to the side surface 14 of the regular polygonal tube body 1A of the rotary polygon mirror 1 of FIGS. 1 and 2 forms a curved surface instead of a flat surface, This curved surface shows a mountain shape on the outer side with respect to the rotating shaft 2.

FIG. 5 shows still another embodiment in which the convex curved surface of FIGS. 3 and 4 is replaced with a concave curved surface, and a case where each side of the regular polygon forms a concave outward with respect to the center of the regular polygon. Shown in Figure 5 (b)
Sections (e) to (e) are cross-sectional views taken along line AB of each example. Figure
5 (b) and 5 (d) are other embodiments corresponding to FIG.
(e) is another embodiment corresponding to FIG. In the embodiment shown in FIGS. 5B and 5C, the reflecting surface 12 of the rotary polygon mirror 1 shown in FIGS.
Reflective surface corresponding to 13 42 (42a, 42b ---), 43 (43a, 43b ---)
Forms a curved surface instead of a flat surface, and this curved surface is a regular polygonal truncated pyramid whose bottom face is a plane in which each side of the regular polygon is concave from the center of the regular polygon from the regular polygonal cylinder 1A, or The curved surface is formed by removing the inverted regular polygonal frustum having the curved plane as an upper surface. Further, the side surface 44 (44a, 44b ---) of the regular polygonal cylinder corresponding to the side surface 14 of the regular polygonal cylinder 1A forms a curved surface instead of a flat surface, and each curved surface has a regular polygonal side. It is a curved surface formed by the outer surface of a cylinder whose bottom surface is a flat surface that is concavely curved with respect to the center of the polygon. That is, there is no bending in the direction of the rotation axis, and the shape is concave outward with respect to the rotation axis 2.

5 (d) and 5 (e), reflecting surfaces corresponding to the first and second reflecting surfaces 12 and 13 of the rotary polygon mirror 1 shown in FIGS.
52 (52a, 52b ---) and 53 (53a, 53b ---) form a curved surface instead of a flat surface, and this curved surface has a valley-shaped curved surface on the outer side with respect to the rotation axis. In addition, a side surface 54 (54a, 54a, 54a, 54a, 54a) of the regular polygonal cylinder corresponding to the side surface 14 of the regular polygonal cylinder 1A of the rotary polygon mirror 1 of FIGS.
b ---) forms a curved surface instead of a flat surface, and this curved surface shows a valley shape on the outside with respect to the rotation axis 2.

Reflecting surfaces 22 (22a, 22b ---), 23 (2) of FIGS.
3a, 23b ---) is a convex curved surface, or the side surface 44 (44a, 44b ---) of FIG. 5 (b), (c) is a concave curved surface, the light beam irradiates the target area 5. The scanning speed at the time of scanning can be controlled. That is, it is possible to realize constant velocity linear scanning and the like. In addition, the side surface 24 (24a, 24b ---) of FIGS. 3 (b) and (c) is a convex curved surface, or the reflecting surface 42 (42a, 42b ---), 43 of FIGS. 5 (b) and (c) is (43a, 43b
If any of ---) is a concave curved surface, the scanning width when the light beam irradiates the target area 5 can be expanded.

When a concave curved surface is added to the reflecting surfaces 52 and 53 in FIGS. 5D and 5E, or a convex curved surface is added to the side surface 34 in FIGS. 4D and 4E,
It is possible to apply a positive power to the light beam 4 and narrow the light beam of the light beam 4. On the contrary, on the other hand, the reflecting surfaces 32, 33 of FIGS.
When a convex curved surface is added to the side surface or a concave curved surface is added to the side surface 54 of FIGS. 5D and 5E, negative power is applied to the light beam 4 and the light beam of the light beam 4 diverges. Therefore, in the embodiment having the mountain-shaped curved surface or the valley-shaped curved surface, the target region 5 located in an arbitrary depth direction can be scanned by selecting these curved surface shapes. Other operations are similar to those of the rotary polygon mirror of the present invention shown in FIG.

Conventionally, the functions of converging and diverging the light beam or the constant velocity linear scanning of the light beam required for a laser beam printer or the like have been entrusted to an optical lens which is independent of the rotating polygon mirror. As in the present invention, among the surfaces forming the transparent body, at least one or more of the surfaces has a convex or concave curved surface shape instead of a flat surface,
The function of the optical lens can be provided, and the same function can be realized without the optical lens.

[0028]

As described above, according to the structure of the present invention, since the reflecting surface of the rotary polygonal mirror is the total reflection surface formed on the inner surface of the rotary polygonal mirror made of a transparent material, Unlike conventional rotary polygon mirrors, the reflective surface does not directly contact the outside world, and a stable state is always maintained, improving its durability. Further, since this transparent body can be manufactured by molding a transparent resin, for example, it is suitable for mass production, has high durability, and can be manufactured at low cost.

If necessary, by adding a convex or concave curved surface to each surface forming the transparent body, the rotary polygon mirror described above can perform not only the conformal scanning of the light beam but also the collection of the light beam. The function of an optical lens such as light / divergence or constant-speed linear scanning of a light beam can be provided, which can contribute to downsizing, weight reduction, and mass productivity of an applied device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a light beam scanner using an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a light beam scanner using another embodiment of the present invention.

FIG. 3 is an explanatory view illustrating a convex curved surface of the rotating polygon mirror of the present invention.

FIG. 4 is an explanatory view illustrating a convex curved surface of the rotary polygon mirror of the present invention.

FIG. 5 is an explanatory view illustrating a concave curved surface of the rotary polygon mirror of the present invention.

FIG. 6 is a perspective view of a prior art light beam scanner.

[Explanation of symbols]

 1 Rotating polygon mirror 1A Regular polygonal cylinder 1B Regular polygonal pyramid 1C Inverse regular polygonal pyramid 12 Reflection surface consisting of total reflection surface 13 Reflection surface consisting of total reflection surface 14 Side surface of regular polygonal cylinder 22, 23, 32 , 33 Convex curved total reflection surface 42, 43, 52, 53 Concave curved total reflection surface 24, 34 Convex curved regular polygonal side surface 44, 54 Concave curved regular surface Side of the rectangular tube

Front page continuation (72) Inventor Tomio Shimizu 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (72) Naoki Kaiho 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Within Fuji Electric Co., Ltd.

Claims (7)

[Claims] 1. A rotary polygonal mirror having a plurality of reflecting surfaces rotationally symmetric with respect to a rotation axis, wherein the plurality of reflecting surfaces are total reflection surfaces formed on an inner surface of a transparent regular polygonal cylinder. A rotating polygon mirror characterized by comprising. 2. The rotating polygon mirror according to claim 1, wherein the plurality of reflecting surfaces are transparent regular polygonal cylindrical bodies, and diagonal lines corresponding to the bottom surface of the regular polygonal cylindrical body in a similar shape and concentric with each other. Is formed by removing a portion of a regular polygonal frustum having a bottom surface corresponding to each other, and includes a first total reflection surface formed on each inner side surface inclined with respect to the outer side surface of the regular polygonal cylinder. Characteristic rotating polygon mirror. 3. The rotating polygon mirror according to claim 1, wherein the plurality of reflecting surfaces are transparent regular polygonal cylindrical bodies, and diagonal lines corresponding to the bottom surface of the regular polygonal cylindrical body in a similar shape and concentric with each other. Except for the portion of the regular polygonal frustum having a bottom surface and the portion of the inverse regular polygonal frustum having a top surface that is similar to the upper surface of the regular polygonal cylinder and has a corresponding diagonal line concentric with each other. A rotary polygon mirror, which is formed of first and second total reflection surfaces formed on each inner surface inclined with respect to the outer surface of the regular polygonal cylindrical body. 4. The rotary polygon mirror according to claim 1, wherein the total reflection surface formed on each inner surface forming the transparent body is at least the first or second total reflection surface. Any one of the reflecting surfaces has a curved surface shape instead of a flat surface, and this curved surface has a plane in which each side of the regular polygon is convex or concave with respect to the center of the regular polygon as a bottom surface. A rotating polygon mirror, which is a curved surface formed by removing the regular polygonal truncated pyramid or the inverted regular polygonal truncated pyramid having the curved plane as an upper surface. 5. The rotating polygon mirror according to claim 1, wherein the outer surface forming the transparent body has a curved surface shape instead of a flat surface, and the curved surface has a regular polygonal shape. Is a curved surface formed by an outer surface of a cylindrical body whose bottom surface is a flat surface that is convex or concave with respect to the center of a regular polygon. 6. The rotary polygon mirror according to claim 1, wherein the total reflection surface formed on each inner surface forming the transparent body is at least the first or second total surface. One of the reflecting surfaces has a curved surface shape instead of a flat surface, and the curved surface has a curved surface of either a peak or a valley on the outer side with respect to the rotation axis. 7. The rotary polygonal mirror according to claim 1, wherein the outer surface forming the transparent body has a curved surface shape instead of a flat surface, and the curved surface is parallel to the rotating shaft. On the other hand, a rotating polygonal mirror having a curved surface of either a mountain or a valley on the outside.