Polygon mirror

Abstract

This polygon mirror has side surface parts (12a-12d) and a support part. The support part has a connection plate part (33), a bearing part (34), attachment parts (35a-35d), and rib parts (37a-37d). The connection plate part (33) is connected to the side surface parts (12a-12d) and is disposed substantially perpendicular to a rotary shaft. The bearing part (34) protrudes to a drive part side with respect to the connection plate part (33) and engages with the rotary shaft. The attachment parts (35a-35d) protrude to the drive part side with respect to the connection plate part (33) and are fixed to a fixing plate. The rib parts (37a-37d) connect the attachment parts (35a-35d). Thus, the polygon mirror is prevented from being damaged.

Description

Polygon mirror

[0001] The present invention relates to a polygon mirror.

[0002] Japanese Patent Application Laid-Open No. 2003-144222 discloses a polygon mirror formed from a resin body.

[0003] Japanese Patent Application Laid-Open No. 2022-182640

[0004] The polygon mirror rotates at high speed, and therefore it is necessary to prevent deformation or breakage due to stress or heat caused by the rotation. The present invention aims to solve such a problem, for example.

[0005] The polygon mirror has a main body integrally formed from synthetic resin and a reflecting portion that reflects light. The main body has a side portion on which the reflecting portion is provided and a support portion that supports the side portion. The support portion is fixed to a fixed plate of a drive unit having a rotation axis and a fixed plate fixed to the rotation axis approximately perpendicular to the rotation axis. The fixed plate rotates with the rotation of the rotation axis, thereby rotating around the rotation axis and rotating the side portion. The support portion has a connecting plate portion connected to the side portion and arranged approximately perpendicular to the rotation axis, a bearing portion that protrudes from the connecting plate portion toward the drive unit and engages with the rotation axis, multiple mounting portions that protrude from the connecting plate portion toward the drive unit and are fixed to the fixed plate, and at least one rib portion connecting the multiple mounting portions.

[0006] In the polygon mirror, the ribs connect the mounting portions, preventing stress from concentrating on the mounting portions and preventing deformation or damage to the polygon mirror.

[0007] 1 is an exploded perspective view showing an example of an optical deflector; a perspective view showing an example of a polygon mirror body; a plan view showing an example of a polygon mirror body; a cross-sectional view taken along line A-B showing an example of a polygon mirror body; a bottom view showing an example of a polygon mirror body; a perspective view cut along line C-D-E showing an example of a polygon mirror body; a bottom view showing another example of a polygon mirror body; a bottom view showing another example of a polygon mirror body; a bottom view showing another example of a polygon mirror body; a bottom view showing another example of a polygon mirror body; a bottom view showing another example of a polygon mirror body; a bottom view showing another example of a polygon mirror body;

[0008] The optical deflector 80 will be described with reference to Fig. 1. The optical deflector 80 includes, for example, a polygon mirror 10, a drive unit 81, and screws 89a to 89d.

[0009] The polygon mirror 10 includes, for example, a main body 11 and reflecting portions 19a to 19d. The main body 11 is integrally formed by injection molding or the like using a synthetic resin such as polycarbonate, acrylic resin, cycloolefin polymer (COP), or cycloolefin copolymer (COC). The reflecting portions 19a to 19d are, for example, planar and reflect light emitted from, for example, a laser light source. The reflecting portions 19a to 19d each include a reflective layer formed by vacuum-depositing a metal such as aluminum, copper, or silver on the surface of the main body 11, and a protective layer formed on the reflective layer to protect the reflective layer. The polygon mirror 10 is attached to the driving unit 81 by fixing means such as screws 89a to 89d.

[0010] The driving unit 81 is, for example, a motor, and rotates the polygon mirror 10. The driving unit 81 has, for example, a driving main body 82, a rotation shaft 83, and a fixed plate 84. The rotation shaft 83 is, for example, cylindrical and has a central axis parallel to the ±Z directions as its center.

[0011] The fixing plate 84 is, for example, a circular plate centered on the central axis of the rotation shaft 83 and perpendicular to the ±Z directions, and is fixed to the rotation shaft 83 by being formed integrally with the rotation shaft 83. The fixing plate 84 has, for example, an upper surface 85 and a plurality of screw holes 86a to 86d. The upper surface 85 is the surface on the +Z side of the fixing plate 84 and is, for example, a circular plane perpendicular to the ±Z directions. The upper surface 85 is an example of a fixing plate abutment plane and abuts against the polygon mirror 10. The screw holes 86a to 86d are, for example, through-holes that pass through the fixing plate 84 perpendicular to the ±Z directions. The screw holes 86a to 86d are, for example, examples of fixing plate screw holes, and have female threads on their inner surfaces that screw into the screws 89a to 89d.

[0012] The drive unit 82 rotates the rotary shaft 83 and the fixed plate 84 around the central axis of the rotary shaft 83. When light emitted from a laser light source or the like is directed onto the reflecting portions 19a-19d of the polygon mirror 10, the reflecting portions 19a-19d reflect the light. Because the drive unit 81 rotates the polygon mirror 10, the direction in which the reflecting portions 19a-19d reflect the light changes depending on the timing, thereby enabling scanning of a predetermined range within a predetermined plane. Furthermore, by changing the angle of the light directed onto the reflecting portions 19a-19d relative to the X-Y plane, the plane scanned by the light reflected by the reflecting portions 19a-19d changes. For example, by simultaneously directing multiple beams of light at different angles relative to the X-Y plane onto the reflecting portions 19a-19d, multiple planes can be scanned simultaneously. By measuring the time it takes for the scanned light to reflect off an object and return, the distance to the object can be measured. This makes it possible to grasp the situation of obstacles, etc., present around a vehicle equipped with the optical deflector 80, for example.

[0013] 2 to 6, the main body 11 of the polygon mirror 10 will be described in more detail. The main body 11 has, for example, side surfaces 12a to 12d and a support portion 13. The side surfaces 12a to 12d are, for example, rectangular plate-like shapes that are substantially parallel to the ±Z directions, and reflecting portions 19a to 19d are provided on the outer surfaces.

[0014] The support portion 13 supports the side surface portions 12a to 12d. The support portion 13 is fixed to a fixed plate 84 of the drive portion 81, and when the fixed plate 84 rotates in conjunction with the rotation of the rotation shaft 83, the support portion 13 rotates around the rotation shaft 83, thereby rotating the side surface portions 12a to 12d. The support portion 13 has, for example, a connection plate portion 33, a bearing portion 34, attachment portions 35a to 35d, and ribs 37a to 37d.

[0015] The connecting plate portion 33 has, for example, a substantially square plate shape and is disposed perpendicular to the ±Z directions. The outer periphery of the connecting plate portion 33 is connected to the side surface portions 12a to 12d. The connecting plate portion 33 has, for example, an upper surface 31 and a lower surface 32. The upper surface 31 is the surface on the +Z side of the connecting plate portion 33 and has, for example, a substantially square outer periphery. The lower surface 32 is the surface on the -Z side of the connecting plate portion 33 and has, for example, a substantially square outer periphery.

[0016] The bearing portion 34 is, for example, substantially cylindrical with its central axis parallel to the ±Z directions, and is disposed in the center of the connecting plate portion 33. The bearing portion 34 protrudes in the −Z direction relative to the connecting plate portion 33 and engages with the rotation shaft 83 of the drive portion 81. The bearing portion 34 has, for example, a shaft hole 41 and a bottom surface 42. The shaft hole 41 is a through-hole that penetrates the bearing portion 34 in the ±Z directions along the central axis of the bearing portion 34, and the rotation shaft 83 of the drive portion 81 is inserted into the shaft hole 41. The bottom surface 42 is the surface on the −Z side of the bearing portion 34 and is, for example, substantially flat and annular. The bottom surface 42 is located on the −Z side of the bottom surface 32 of the connecting plate portion 33.

[0017] The mounting portions 35a to 35d are disposed at positions spaced a predetermined distance from the center of the connecting plate portion 33, and protrude in the −Z direction relative to the connecting plate portion 33. The mounting portions 35a to 35d are fixed to a fixed plate 84 of the driving portion 81. The mounting portions 35a to 35d have, for example, base portions 51a to 51d and end portions 53a to 53d.

[0018] The bases 51a to 51d are, for example, substantially truncated cones with central axes parallel to the ±Z directions, and protrude in the -Z direction relative to the connecting plate 33. The bases 51a to 51d have, for example, recesses 52a to 52d. The recesses 52a to 52d are recessed in the -Z direction from the upper surface 31 of the connecting plate 33 toward the bases 51a to 51d. The recesses 52a to 52d are, for example, substantially truncated cones with central axes parallel to the ±Z directions.

[0019] The end portions 53a to 53d are, for example, generally cylindrical with their central axes parallel to the ±Z directions, and protrude further in the -Z direction from the -Z side surfaces of the base portions 51a to 51d. The end portions 53a to 53d have, for example, screw holes 54a to 54d and bottom surfaces 55a to 55d. The screw holes 54a to 54d are through-holes that penetrate the end portions 53a to 53d in the -Z direction from the bottom surfaces of the recesses 52a to 52d. The screw holes 54a to 54d are an example of mounting screw holes, through which screws 89a to 89d are inserted. The bottom surfaces 55a to 55d are, for example, generally annular flat surfaces, that are located on the -Z side of the end portions 53a to 53d relative to the bottom surface 32 of the connecting plate portion 33 and are located on the -Z side relative to the bottom surface 42 of the bearing portion 34. The lower surfaces 55a to 55d are examples of flat mounting abutment surfaces, and abut against the upper surface 85 of the fixed plate 84.

[0020] The rib portion 37a connects the mounting portion 35a and the mounting portion 35b. The rib portion 37b connects the mounting portion 35b and the mounting portion 35c. The rib portion 37c connects the mounting portion 35c and the mounting portion 35d. The rib portion 37d connects the mounting portion 35d and the mounting portion 35a. The rib portions 37a to 37d are, for example, in the shape of an annular sector column centered on the central axis of the bearing portion 34 (a shape obtained by cutting out a part of a cylinder by two planes passing through the central axis). The +Z side ends of the rib portions 37a to 37d are connected to the lower surface 32 of the connecting plate portion 33. The rib portions 37a to 37d have, for example, lower surfaces 72a to 72d. The lower surfaces 72a to 72d are surfaces on the -Z side of the rib portions 37a to 37d, and have, for example, a circular sector-shaped planar shape (a shape obtained by cutting out a portion of a circle by two straight lines passing through the center). The lower surfaces 72a to 72d are located on the -Z side of the lower surface 32 of the connecting plate portion 33, and are flush with the lower surfaces 55a to 55d of the mounting portions 35a to 35d. The lower surfaces 72a to 72d are an example of a rib abutment plane, and abut against the upper surface 85 of the fixing plate 84.

[0021] When the drive unit 81 rotates the rotary shaft 83 and the fixed plate 84, the rotational motion of the fixed plate 84 is transmitted to the polygon mirror 10 via the screws 89a to 89d. This causes stress to concentrate on the mounting portions 35a to 35d. In particular, when multiple laser beams are simultaneously directed at the reflecting portions 19a to 19d in order to simultaneously scan multiple planes, the lengths of the side portions 12a to 12d in the ±Z directions are lengthened to distribute the areas on which the laser beams are directed, which increases the weight of the main body 11. This increases the force applied to the mounting portions 35a to 35d and the resulting stress, making the mounting portions 35a to 35d more susceptible to deformation or damage.

[0022] The polygon mirror 10 has ribs 37a to 37d connecting the mounting portions 35a to 35d, which prevents stress from concentrating on the mounting portions 35a to 35d, thereby increasing the strength of the support portion 13 and preventing deformation or damage to the polygon mirror 10.

[0023] Because the lower surfaces 72a to 72d of the ribs 37a to 37d are flush with the lower surfaces 55a to 55d of the mounting portions 35a to 35d, the contact area of ​​the support portion 13 with the fixed plate 84 increases, and force can be dispersed. Also, there is no step between the mounting portions 35a to 35d and the ribs 37a to 37d, which prevents stress from concentrating on the step portion, thereby preventing deformation or damage to the polygon mirror 10.

[0024] Since the rib parts 37a to 37d are in the shape of a circular sector column, the resistance caused by the rotation of the polygon mirror 10 is small, and the force applied to the mounting parts 35a to 35d can be reduced, thereby preventing the polygon mirror 10 from being deformed or damaged.

[0025] The main body 11A will be described with reference to FIG. 7. The polygon mirror 10 may have a main body 11A instead of the main body 11. The main body 11A is similar to the main body 11, but differs in that it has ribs 37e to 37h instead of the ribs 37a to 37d. The ribs 37e to 37h connect the mounting portions 35a to 35d, just like the ribs 37a to 37d. However, unlike the ribs 37a to 37d, the ribs 37e to 37h are flat and connect the mounting portions 35a to 35d in a straight line.

[0026] The main body 11B will be described with reference to Figure 8. The polygon mirror 10 may have a main body 11B instead of the main body 11. The main body 11B is similar to the main body 11, but differs in that it has ribs 37i to 37l instead of the ribs 37a to 37d. The ribs 37i to 37l connect the mounting portions 35a to 35d, just like the ribs 37a to 37d. However, unlike the ribs 37a to 37d, the ribs 37i to 37l are curved flat plates, connecting the mounting portions 35a to 35d in a broken line.

[0027] In this way, the shape of the rib portion is not limited to a circular sector columnar shape, and may be other shapes.

[0028] The main body 11C will be described with reference to FIG. 9. The polygon mirror 10 may have the main body 11C instead of the main body 11. The main body 11C is similar to the main body 11, but differs in that it further includes ribs 37m-37p. The ribs 37m-37p are an example of side ribs, and connect the mounting portions 35a-35d to the side portions 12a-12d. In this way, by connecting the mounting portions 35a-35d not only to each other but also to the side portions 12a-12d, the strength of the mounting portions 35a-35d can be further increased.

[0029] The main body 11D will be described with reference to FIG. 10. The polygon mirror 10 may have the main body 11D instead of the main body 11. The main body 11D is similar to the main body 11, but differs in that it further includes ribs 37q to 37t. The ribs 37q to 37t are an example of rib side rib portions, and connect the ribs 37a to 37d to the side surfaces 12a to 12d. In this way, by connecting the mounting portions 35a to 35d with the ribs 37a to 37d, as well as connecting the ribs 37a to 37d to the side surfaces 12a to 12d, the strength of the mounting portions 35a to 35d can be further increased.

[0030] The main body 11E will be described with reference to FIG. 11. The polygon mirror 10 may have the main body 11E instead of the main body 11. The main body 11E is similar to the main body 11, but differs in that it further includes ribs 37u to 37x. The ribs 37u to 37x are an example of bearing ribs, and connect the mounting portions 35a to 35d to the bearing portion 34. In this way, by connecting the mounting portions 35a to 35d with the ribs 37a to 37d, as well as connecting the mounting portions 35a to 35d to the bearing portion 34, the strength of the mounting portions 35a to 35d can be further increased.

[0031] The main body 11F will be described with reference to FIG. 12. The polygon mirror 10 may have a main body 11F instead of the main body 11. The main body 11F is similar to the main body 11, but differs in that it further includes vertical wall portions 38a-38t. The vertical wall portions 38a-38t are flat plates extending in the ±Z direction and protrude from the mounting portions 35a-35d in a direction approximately perpendicular to the ±Z direction. In this way, not only are the mounting portions 35a-35d connected by the ribs 37a-37d, but the vertical wall portions 38a-38t protrude from the mounting portions 35a-35d, thereby further increasing the strength of the mounting portions 35a-35d.

[0032] As described above, by further increasing the strength of the mounting portions 35a to 35d, it is possible to prevent the mounting portions 35a to 35d from being damaged.

[0033] The above-described embodiment is an example for facilitating understanding of the present invention. The present invention is not limited thereto, and includes various modifications, changes, additions, or omissions without departing from the scope defined by the appended claims. This can be easily understood by those skilled in the art from the above description.

[0034] For example, the number of side surfaces is not limited to four and may be three, or five or more. The number of attachment portions is not limited to four and may be three, or five or more, and may be different from the number of side surfaces. Furthermore, the lower surface of the attachment portion may be flush with the lower surface of the bearing portion, rather than being located on the -Z side of the lower surface of the bearing portion.

[0035] 10 Polygon mirror, 11, 11A to 11F Main body, 12a to 12d Side portion, 13 Support portion, 19a to 19d Reflecting portion, 33 Connection plate portion, 34 Bearing portion, 35a to 35d Mounting portion, 37a to 37x Rib portion, 38a to 38t Vertical wall portion, 31, 85 Upper surface, 32, 42, 55a to 55d, 72a to 72d Lower surface, 41 Shaft hole, 51a to 51d Base portion, 52a to 52d Recessed portion, 53a to 53d End portion, 54a to 54d, 86a to 86d Screw hole, 80 Optical deflector, 81 Drive portion, 82 Drive main body, 83 Rotating shaft, 84 Fixing plate, 89a to 89d Screw.

Claims

1. A polygon mirror comprising: a main body integrally formed from synthetic resin; and a reflecting portion that reflects light; wherein the main body has a side portion on which the reflecting portion is provided; and a support portion that supports the side portion; the support portion is fixed to a fixed plate of a drive unit having a rotation axis and a fixed plate fixed to the rotation axis approximately perpendicular to the rotation axis; the fixed plate rotates in conjunction with the rotation of the rotation axis, thereby rotating around the rotation axis and rotating the side portion; and the support portion has: a connecting plate portion connected to the side portion and arranged approximately perpendicular to the rotation axis; a bearing portion that protrudes from the connecting plate portion toward the drive unit and engages with the rotation axis; a plurality of mounting portions that protrude from the connecting plate portion toward the drive unit and are fixed to the fixed plate; and at least one rib portion connecting the plurality of mounting portions.

2. The polygon mirror of claim 1, wherein each of the mounting portions has a mounting screw hole through which a screw that threads into a mounting plate screw hole provided in the mounting plate is inserted, and a mounting abutment plane that abuts against a mounting plate abutment plane of the mounting plate that is approximately perpendicular to the rotation axis, and the rib portion has a rib abutment plane that abuts against the mounting plate, and the rib abutment plane is provided flush with the mounting abutment plane.

3. The polygon mirror according to claim 1 or 2, wherein the rib portion is in the shape of a circular sector column centered on the central axis of the bearing portion.

4. The polygon mirror according to claim 1 or 2, wherein the support portion further has a bearing rib portion connecting the mounting portion and the bearing portion.

5. The polygon mirror according to claim 1 or 2, wherein the support portion further has a side rib portion connecting the mounting portion and the side portion.

6. The polygon mirror according to claim 1 or 2, wherein the support portion further comprises a rib / side rib portion connecting the rib portion and the side portion.

7. The polygon mirror according to claim 1 or 2, wherein the support portion further has a vertical wall portion extending in a direction substantially parallel to the central axis of the bearing portion and protruding from the mounting portion in a direction substantially perpendicular to the central axis.

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