Polygon mirror

Abstract

To provide a polygon mirror appropriately provided with an index indicating a base point of rotation.SOLUTION: The polygon mirror comprises: a mirror surface 2 provided on a side surface for reflecting a laser beam; and an index part 3 provided, as index indicating the base point of rotation, on a convex polygon surface 11 perpendicular to the side surface and including a concave-formed recess.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a polygon mirror. [Background technology]

[0002] It is generally known to use a polygon mirror for scanning a laser (see, for example, Patent Document 1). When attaching a polygon mirror to a motor, an index indicating the base point of rotation may be provided on the motor to perform balance correction to suppress vibration caused by misalignment of parts. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-170049 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the index indicating the base point of rotation is provided in the motor, not in the polygon mirror. The present embodiment aims to provide a polygon mirror in which an index indicating the base point of rotation is appropriately provided. Effect of the Invention

[0005] According to the embodiment, it is possible to provide a polygon mirror in which an index indicating a base point of rotation is appropriately provided. [Means for solving the problem]

[0006] A polygon mirror according to an embodiment of the present invention comprises a mirror surface provided on a side surface to reflect laser light, and an index portion including a concave recess provided on a convex polygonal surface perpendicular to the side surface as an index indicating the base point of rotation. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing a configuration of a polygon mirror according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of the vicinity of an index portion of the surface of the polygon mirror according to the first embodiment. [Diagram 3] 3 is a cross-sectional view of the surface of the polygon mirror according to the first embodiment shown in FIG. 2 in the vicinity of the index portion, taken along line AA. [Figure 4] FIG. 11 is a perspective view showing the configuration of a polygon mirror according to a second embodiment of the present invention. [Diagram 5] FIG. 11 is an enlarged view of the vicinity of an index portion of a surface of a polygon mirror according to a second embodiment. [Figure 6] 6 is a cross-sectional view of the surface of the polygon mirror according to the second embodiment shown in FIG. 5 in the vicinity of the index portion, taken along line BB. [Figure 7] FIG. 11 is an enlarged view of the vicinity of an index portion on a surface of a modified example of the polygon mirror according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (First embodiment) 1 is a perspective view showing the configuration of a polygon mirror 1 according to a first embodiment of the present invention. In the drawings, the same parts are denoted by the same reference numerals.

[0009] The polygon mirror 1 is an optical component that scans a laser by rotating. The polygon mirror 1 is attached to a motor and used. For example, the polygon mirror 1 is used in LiDAR (light detection and ranging). LiDAR is an optical sensor technology that irradiates an object with a laser beam while scanning it, measures the distance and position of the object, and identifies the properties of the object.

[0010] The polygon mirror 1 has a columnar shape with a convex polygonal cross section (or front and back surfaces). The polygon mirror 1 has a circular hole H1 that penetrates from the center of the front surface to the back surface. The rotating shaft of a motor to which the polygon mirror 1 is attached is inserted and fixed in the hole H1. Here, the polygon mirror 1 is mainly described as having a columnar shape with a square cross section (i.e., a rectangular parallelepiped), but any shape may be used as long as the cross section is a columnar shape of any convex polygon. Furthermore, the polygon mirror 1 may have a shape like a tilt mirror. The tilt mirror has a shape of a convex polygon with parallel front and back surfaces, and has trapezoidal side surfaces (mirror surfaces 2) that are inclined with respect to a perpendicular plane to the front and back surfaces. The polygon mirror 1 has a plurality of mirror surfaces 2 and an index unit 3. The mirror surface 2 reflects the laser light emitted from the light source when the polygon mirror 1 rotates. The laser light reflected by the mirror surface 2 is irradiated onto an object in a scanning manner. The mirror surface 2 corresponds to the side surfaces of the polygon mirror 1. Therefore, the number of mirror surfaces 2 is the number of side surfaces of the polygon mirror 1. Here, since the polygon mirror 1 is described as a rectangular parallelepiped, the number of mirror surfaces 2 is four.

[0011] The index unit 3 is an index that indicates the base point of rotation of the polygon mirror 1 (or the multiple mirror surfaces 2) in order to perform balance correction to suppress vibrations caused by misalignment of parts, etc. The index unit 3 is provided near one of the multiple vertices of the convex polygonal (e.g., quadrangular) surface 11 of the polygon mirror 1. Surface 11 is a convex polygonal surface that is perpendicular to the multiple surfaces (side surfaces) on which the multiple mirror surfaces 2 of the polygon mirror 1 are respectively arranged. Surface 11 may be the front surface of the polygon mirror 1 or the back surface of the polygon mirror 1. For example, surface 11 of the polygon mirror 1 is the surface on the side to which a motor is attached.

[0012] The index portion 3 will be described in detail with reference to Figures 2 and 3. Figure 2 is an enlarged view of the vicinity of the index portion 3 on the surface 11 of the polygon mirror 1. Figure 3 is a cross-sectional view taken along line AA of the vicinity of the index portion 3 on the surface 11 shown in Figure 2.

[0013] The index portion 3 is configured such that a concave recess D11 is formed near one vertex of the face 11 and is filled with ink 31.

[0014] Any material may be used as the ink 31 as long as it can function as an index indicating the base point of rotation. For example, when using a sensor that detects the index portion 3 (base point of rotation) by utilizing color contrast (change in light reflectance), the ink 31 has the function of not reflecting light.

[0015] When a sensor capable of detecting a step is used as the sensor for detecting the index portion 3, the ink 31 does not need to be applied, and the recess D11 alone can function as an index. For example, a sensor capable of detecting a step is a laser distance sensor, a capacitive macro sensor, or the like.

[0016] The recess D11 serves as a frame for applying the ink 31. Providing the recess D11 prevents variation in the application (marking) of the ink 31. For example, when applying the ink 31, the ink 31 tends to fit inside the recess D11, and the ink 31 is always applied over a constant area.

[0017] Even if the index portion 3 is rubbed during transportation or packaging of the polygon mirror 1, the provision of the recess D11 makes it difficult for the rubbed ink 31 to spread outside the recess D11. It is also desirable that the ink 31 does not rise higher than the surface 11 on which the recess D11 is provided. This makes it possible to prevent the ink 31 from rubbing against other members (for example, packaging materials).

[0018] According to this embodiment, by providing the recess D11 as the index portion 3 indicating the base point of rotation, the ink 31 can be appropriately applied to the recess D11 and the ink 31 can be prevented from rubbing off.

[0019] For example, a polygon mirror having an index part with ink 31 directly applied to its surface 11, without providing a recess D11, unlike the present embodiment, will be described below. When this polygon mirror is transported in a container such as a plastic tray, the surface 11 comes into contact with the container during transportation, and the ink 31 in the index part also comes into contact with the container. This makes the ink 31 more likely to be rubbed against the container. In contrast, by providing the recess D11 as in the present embodiment, the container can be prevented from coming into contact with the ink 31, and the ink 31 can be prevented from being rubbed. In addition, when a sensor capable of detecting a step is used as a sensor for detecting the base point of rotation of the polygon mirror 1, the index part 3 is formed only with the recess D11, and ink 31 does not need to be applied. This eliminates the need to worry about the ink 31 in the index part 3 being rubbed when the polygon mirror 1 is transported or packed.

[0020] Second embodiment FIG. 4 is a perspective view showing the configuration of a polygon mirror 1A according to the second embodiment of the present invention.

[0021] The polygon mirror 1A is obtained by replacing the surface 11 and the index portion 3 of the polygon mirror 1 according to the first embodiment with a surface 11A and an index portion 3A, respectively. In other respects, the polygon mirror 1A is similar to that of the first embodiment.

[0022] A ring-shaped protrusion P11 is formed on the surface 11A on which the index portion 3A is provided. The ring-shaped protrusion P11 is formed in a protruding shape so as to rise in a ring shape that spreads over the entire surface 11A with the hole H1 as its center.

[0023] For example, the ring-shaped protrusion P11 is provided for the purpose of fixing the polygon mirror 1A, preventing deformation of the mirror surface 2, or serving as a reference for processing the polygon mirror 1A. Note that the ring-shaped protrusion P11 may be provided for any purpose, or may not be provided at all.

[0024] The index portion 3A will be described with reference to Figures 5 and 6. Figure 5 is an enlarged view of the vicinity of the index portion 3A on the surface 11A of the polygon mirror 1A. Figure 6 is a cross-sectional view taken along line BB of the vicinity of the index portion 3A on the surface 11A shown in Figure 5.

[0025] The index section 3A is similar to the index section 3 according to the first embodiment except for the difference in configuration. Here, the differences from the index section 3 according to the first embodiment will be mainly described.

[0026] The index portion 3A includes a recess D11A, a protrusion P12, and ink 31.

[0027] The recess D11A is formed so as to extend linearly from near the vertex of the surface 11A toward the center of the surface 11A to reach the ring-shaped protrusion P11. That is, the recess D11A is provided near the vertex of the surface 11A so as to draw a diagonal line of the surface 11A.

[0028] The protrusion P12 is formed in the center of the width direction inside the recess D11A so as to protrude linearly parallel to the recess D11A. The upper surface of the protrusion P12 is the surface to which the ink 31 is applied. As in the first embodiment, the ink 31 does not necessarily have to be applied.

[0029] For example, when applying ink 31 to flat surface 11A with a marker with a rounded tip, the thickness of the applied ink 31 changes depending on the pressure of the marker. For this reason, it is not easy to apply ink 31 only to a predetermined area of ​​flat surface 11A. In contrast, index part 3A has recesses D11A formed on both sides of protrusion P12, so that ink 31 can always be easily applied only to the predetermined area (the upper surface of protrusion P12).

[0030] The height of the upper surface of the convex portion P12 may be changed as desired. For example, the height of the upper surface of the convex portion P12 can be easily formed by designing the height of the upper surface of the convex portion P12 to be the same height as the surface 11A. Specifically, the portion of the surface 11A to be the convex portion P12 (the portion to which the ink 31 is applied) is determined, and the concave portions D11A are formed on both sides of the convex portion P12 so as to leave the convex portion P12, whereby the convex portion P12 can be easily formed on the surface 11A.

[0031] Furthermore, by making the height of the upper surface of the convex portion P12 lower than the surface 11A, it is possible to prevent the ink 31 applied to the upper surface of the convex portion P12 from rubbing against other members (packaging material, etc.). Furthermore, by making the height of the convex portion P12 plus the height of the ink 31 lower than the surface 11A in a state in which the ink 31 is applied to the convex portion P12, it is possible to further prevent the ink 31 from rubbing against other members (packaging material, etc.).

[0032] In the index portion 3A, the convex portion P12 and the concave portion D11A as shown in Fig. 5 do not have to reach the apex of the surface 11A. For example, as shown in Fig. 7, in the index portion 3Aa, the concave portion D11Aa is formed so that both sides and the apex side of the convex portion P12a are all connected. A ring-shaped convex portion P11 is provided on the side opposite the apex side of the convex portion P12a. This makes it easier to apply the ink 31 to the upper surface of the convex portion P12a.

[0033] According to this embodiment, by providing the concave portion D11A and the convex portion P12 as the index portion 3A, the ink 31 can be appropriately applied to the upper surface of the convex portion P12.

[0034] Furthermore, the index part 3A may be configured only by the shapes of the recessed part D11A and the protruding part P12, without applying the ink 31, as in the first embodiment. This eliminates the need to worry about the ink 31 on the index part 3A being rubbed off during transportation or packaging of the polygon mirror 1A.

[0035] However, additional advantages and modifications may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific detailed representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0036] 1...polygon mirror, 2...mirror surface, 3...index portion, 31...ink, D11...recess, H1...hole.

Claims

1. A mirror surface provided on the side for reflecting the laser light; an index portion including a concave recess formed on a convex polygonal surface different from the side surface as an index indicating a base point of rotation; A polygon mirror comprising:

2. The index portion has an inner surface of the recess coated with ink.

2. The polygon mirror according to claim 1,

3. The index portion includes a protrusion formed in a protruding shape inside the recess.

2. The polygon mirror according to claim 1,

4. Ink is applied to the upper surface of the protrusion.

4. The polygon mirror according to claim 3,

5. The height of the convex portion is equal to or less than the height of the face of the convex polygon.

4. The polygon mirror according to claim 3,

Images