Rotating mirror, method for manufacturing a rotating mirror

Abstract

The present invention provides a rotating mirror and a method for manufacturing the same that can improve productivity, reduce costs, and ensure the accuracy of the reflective surface through improved rigidity. [Solution] A polygonal mirror 3 that rotates or oscillates around a rotation axis AX and scans by reflecting incident light 7i, comprising: a resin part 17 made of a resin material having an outer surface 17a into which light 7i is incident, and an inner surface 17b located on the opposite side of the outer surface 17a in the direction of incidence of light 7i and into which light 7i is not incident; a glass film 21 made of a glass material formed on both the outer surface 17a and the inner surface 17b; and a metal film 19 made of a metal material formed between the resin part 17 and the glass film 21 on both the outer surface 17a and the inner surface 17b.

Description

Technical Field

[0006] ,

[0001] The present invention relates to a rotating mirror that rotates or swings about a rotation axis and reflects incident light for scanning, and a method for manufacturing the same.

Background Art

[0002] Conventionally, a rotating mirror that rotates or swings about a rotation axis and reflects incident light for scanning is known. The rotating mirror is used, for example, in a LiDAR device, a laser scanner, a laser marker, a laser printer, etc. to scan light emitted from a light source. As the rotating mirror, for example, a polygonal mirror, a cylindrical mirror, a flat mirror, etc. are known.

[0003] For example, Patent Document 1 describes a polygon mirror which is an example of a polygonal mirror. This polygon mirror forms a reflective surface by vapor-depositing aluminum on each side surface portion of a hexagonal columnar body formed of resin.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The reflective surface of the rotating mirror is required to have high accuracy in order to accurately reflect incident light in a desired direction. The required accuracy includes, for example, the surface accuracy of the reflective surface, the angular accuracy of the reflective surface, and the runout accuracy during rotation.

[0006] The conventional polygon mirror described above is used by being rotated by a drive device, so centrifugal force acts on each side. However, since resin polygon mirrors have lower rigidity than metal ones, there is a risk that slight deformation such as bending may occur on the reflective surface due to centrifugal force. In addition, since the reflective surface is formed by depositing a metal film such as aluminum on the resin, there is a risk that slight deformation such as bending may occur on the reflective surface due to temperature changes caused by the difference in thermal expansion coefficients between the resin and the metal film. Thus, the conventional polygon mirror described above has the problem that the accuracy of the reflective surface may decrease.

[0007] The object of the present invention is to provide a rotating mirror and a method for manufacturing the same that can improve productivity, reduce costs, and ensure accuracy of the reflective surface by improving rigidity. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides a rotating mirror that rotates or oscillates about a rotation axis and scans by reflecting incident light, comprising: a resin portion made of a resin material having a first surface into which the light is incident and a second surface located on the opposite side of the first surface in the direction of the incident light and into which the light is not incident; a glass film made of a glass material formed on both the first surface and the second surface; and a metal film made of a metal material formed between the resin portion and the glass film on at least the first surface of the first and second surfaces.

[0009] Furthermore, in order to achieve the above objective, the present invention provides a method for manufacturing a rotating mirror that rotates or oscillates around a rotation axis and scans by reflecting incident light, comprising: a first step of injecting molten resin material into a mold to form a resin part having a first surface on which the light is incident and a second surface located on the opposite side of the first surface in the direction of the incident light and on which the light is not incident; a second step of forming a metal film made of a metal material on at least the first surface of the first and second surfaces; and a third step of forming a glass film made of a glass material on both surfaces of the first and second surfaces.

[0010] The rotating mirror of the present invention comprises a resin portion, a metal film, and a glass film, and is rotated or oscillated around a rotation axis. A metal film is formed on at least the first surface of the resin portion, and incident light is reflected by the metal film and scanned. Since the base resin portion of the rotating mirror of the present invention can be formed by injection molding or compression molding, precision machining by cutting, as is required when using metal materials for the base shape, is unnecessary, and the time required for manufacturing can be significantly reduced. Therefore, productivity can be improved and costs can be reduced. Furthermore, in this invention, glass films are formed on both the first and second surfaces of the resin part. This allows the glass films on both sides to suppress deflection and twisting of the resin part due to external forces such as centrifugal force, thereby preventing deformation of the resin part. Also, deformation such as deflection due to temperature changes caused by the difference in thermal expansion coefficients between the resin and the glass film can be suppressed by the glass films on both sides, thus preventing deformation of the resin part. In this way, the rigidity of the rotating mirror can be improved, and the shape stability against temperature changes can be improved, thereby ensuring the accuracy of the reflective surface. Furthermore, covering the entire resin and metal film with a glass film also has the effect of improving heat resistance, the insulating and corrosion-resistant properties of the metal film, and the chemical resistance of the resin part to gases such as chlorine and hydrogen sulfide. [Effects of the Invention]

[0011] According to the present invention, productivity can be improved, costs can be reduced, and the accuracy of the reflective surface can be ensured by improving rigidity. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view showing an example of the overall configuration of a polygonal mirror unit equipped with a polygonal mirror and a motor according to the first embodiment. [Figure 2] This is a cross-sectional view corresponding to the II-II section in Figure 1, showing an example of the overall configuration of the polygonal mirror unit according to the first embodiment. [Figure 3]It is a perspective view seen from above showing an example of the configuration of a polygonal mirror according to the first embodiment. [Figure 4] It is a perspective view seen from below showing an example of the configuration of a polygonal mirror according to the first embodiment. [Figure 5] It is a cross-sectional view corresponding to region A of FIG. 2, showing an example of the film configuration of a polygonal mirror according to the first embodiment. [Figure 6] It is a cross-sectional view corresponding to region B of FIG. 2, showing an example of the film configuration of a polygonal mirror according to the first embodiment. [Figure 7] It is a flowchart showing an example of the manufacturing procedure of a polygonal mirror according to the first embodiment. [Figure 8] It is an explanatory diagram showing that when a metal film and a glass film are formed only on the outer surface of the resin part, deflection occurs according to temperature change due to the difference in the thermal expansion coefficients of the resin part and the glass film. [Figure 9] It is a cross-sectional view showing an example of the film configuration of a polygonal mirror according to the first embodiment. [Figure 10] It is a cross-sectional view corresponding to region A of FIG. 2, showing an example of the film configuration of a polygonal mirror according to a modified example of the first embodiment. [Figure 11] It is a perspective view showing an example of the overall configuration of a cylindrical mirror unit including a cylindrical mirror and a motor according to the second embodiment. [Figure 12] It is a cross-sectional view corresponding to the XII-XII cross-section of FIG. 1, showing an example of the cross-sectional configuration and film configuration of a cylindrical mirror according to the second embodiment. [Figure 13] It is a perspective view showing an example of the overall configuration of a flat mirror unit including a flat mirror and a motor according to the third embodiment. [Figure 14] It is a cross-sectional view corresponding to the XIV-XIV cross-section of FIG. 13, showing an example of the cross-sectional configuration and film configuration of a flat mirror according to the third embodiment.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The rotating mirror according to this embodiment is used to scan light emitted from a light source, for example, in a LiDAR device, a laser scanner, a laser marker, a laser printer, or the like. The rotating mirror is classified into a polygonal mirror, a cylindrical mirror, and a flat mirror according to the shape of the mirror.

[0014] <First Embodiment> The first embodiment is an embodiment in the case where the rotating mirror is a polygonal mirror. The polygonal mirror is also referred to as a polygon mirror or a polyhedron mirror. The first embodiment will be described with reference to FIGS. 1 to 10.

[0015] (Configuration of Polygonal Mirror Unit and Polygonal Mirror) FIG. 1 is a perspective view showing an example of the overall configuration of a polygonal mirror unit including a polygonal mirror and a motor according to the first embodiment. FIG. 2 is a cross-sectional view corresponding to the II-II cross-section of FIG. 1, showing an example of the overall configuration of the polygonal mirror unit according to the first embodiment. FIG. 3 is a perspective view seen from above showing an example of the configuration of the polygonal mirror according to the first embodiment. FIG. 4 is a perspective view seen from below showing an example of the configuration of the polygonal mirror according to the first embodiment. In FIG. 2, the illustration of the internal structure of the motor is omitted.

[0016] As shown in FIGS. 1 and 2, the polygonal mirror unit 1 includes a polygonal mirror 3 that is rotated about the rotation axis AX and reflects the incident light 7i for scanning, and a motor 5 that rotationally drives the polygonal mirror 3 about the rotation axis AX. The polygonal mirror 3 is formed in a substantially quadrangular shape when viewed from the direction of the rotation axis AX. Note that the shape of the polygonal mirror 3 is not limited to a quadrangle, and may be a polygon such as a triangle, a pentagon, a hexagon, an octagon, or the like.

[0017] The polygonal mirror 3 (an example of a rotating mirror) has a connection part 3A to the motor 5 and four reflective parts 3B arranged to surround the connection part 3A, and is formed in a roughly box shape with an open bottom. Each of the four reflective parts 3B is a roughly square plate-like member and is connected to each other at roughly right angles. The outer surfaces of the four reflective parts 3B constitute a reflective surface 3Ba that reflects incident light 7i. As shown in Figure 1, light 7i emitted from a light source (not shown) is incident on the reflective surface 3Ba of the polygonal mirror 3. When the polygonal mirror 3 rotates around the rotation axis AX, the reflective surface 3Ba of each reflective part 3B sequentially reaches the incident position of the light 7i, and the light 7i is reflected by each reflective surface 3Ba. As a result, the direction of propagation of the reflected light 7o changes with time in accordance with the rotation of the reflective surface 3Ba, and the reflected light 7o is sequentially scanned over a predetermined area.

[0018] As a light source, for example, a semiconductor laser, LED, or other light-emitting element can be used. The light emitted from the light source is, for example, laser light, visible light, or infrared light.

[0019] The connecting portion 3A is a plate-like member with a roughly rectangular shape and is connected to each of the four reflecting portions 3B at roughly right angles. As shown in Figures 3 and 4, the connecting portion 3A has a shaft hole 3a for which the output shaft 5A of the motor 5 is fixed, and a number of (e.g., three) through holes 3b through which screws 9 for fixing the polygonal mirror 3 to the motor 5 pass. The shaft hole 3a is located approximately in the center of the connecting portion 3A, and the through holes 3b are arranged at roughly equal intervals in the circumferential direction centered on the shaft hole 3a. Below the connecting portion 3A, a recess 11 is formed, which is the inner space of the polygonal mirror 3 surrounded by the four reflecting portions 3B.

[0020] As shown in Figures 1 and 2, the motor 5 (an example of a drive device) is positioned at the bottom of the polygonal mirror 3 and rotates the polygonal mirror 3 around the rotation axis AX. The motor 5 may continuously rotate the polygonal mirror 3 in a predetermined rotation direction (for example, arrow 13 in Figure 1), change the rotation direction and rotate it back and forth, or oscillate it within a predetermined angular range. As shown in Figure 2, the motor 5 has an output shaft 5A that rotates around the rotation axis AX, a bearing part 5B that rotatably supports the output shaft 5A, and an electromagnetic part 5C that generates a driving force to rotate the output shaft 5A. The output shaft 5A and the bearing part 5B of the motor 5 are housed in the recess 11 of the polygonal mirror 3. A disc-shaped or rectangular plate-shaped support member 15 is fixed to the output shaft 5A. The support member 15 rotates together with the output shaft 5A. The support member 15 has a screw hole 15a formed in it at a position corresponding to the through hole 3b of the connecting part 3A of the polygonal mirror 3. Multiple screws (for example, three) 9 are fastened through the through-holes 3b of the connecting portion 3A of the polygonal mirror 3 into the screw holes 15a of the support member 15, thereby fixing the polygonal mirror 3 to the support member 15.

[0021] (Membrane structure of polygonal mirrors) Figure 5 is a cross-sectional view corresponding to region A in Figure 2, showing an example of the film structure of the polygonal mirror 3 according to the first embodiment. Figure 6 is a cross-sectional view corresponding to region B in Figure 2, showing an example of the film structure of the polygonal mirror 3 according to the first embodiment.

[0022] As shown in Figures 5 and 6, the polygonal mirror 3 comprises a resin part 17, a metal film 19, and a glass film 21. The resin part 17 is made of a resin material and constitutes the base shape of the polygonal mirror 3. The resin part 17 has an outer surface 17a (an example of a first surface) to which light 7i is incident, and an inner surface 17b (an example of a second surface) located on the opposite side of the outer surface 17a in the direction of incidence of light 7i, and to which light 7i is not incident. As the resin material, for example, COC (cycloolefin copolymer), COP (cycloolefin polymer), etc., which have excellent dimensional stability even in high temperature and high humidity environments may be used, or PC (polycarbonate), PMMA (polymethyl methacrylate), etc., may be used depending on the required precision. In addition, resin materials other than those mentioned above may be used. The surface of the resin part 17 is subjected to surface modification treatments such as plasma treatment, corona discharge treatment, ultraviolet treatment, or chemical etching treatment in order to improve adhesion with the metal film 19.

[0023] The metal film 19 is made of a metal material and is formed between the resin part 17 and the glass film 21 on both the outer surface 17a and the inner surface 17b of the resin part 17. The metal film 19 is formed, for example, by sputtering using a highly reflective metal material such as aluminum, gold, silver, or copper. In addition to the above metals, alloys with improved durability and secondary processability may also be used. Sputtering is also called the sputtering method. In sputtering, the metal material and the resin part 17 are placed in a container, the container is evacuated, and an inert gas (such as argon) is introduced. When a high voltage is applied between the resin part 17 and the metal material, electrons and ions of argon move at high speed and collide with the metal material, causing a sputtering phenomenon, which blasts away particles of the metal material, and they adhere to the surface of the resin part 17. In this way, a thin film of metal material is formed on the surface of the resin part 17. In the four reflective sections 3B of the polygonal mirror 3, the metal film 19 formed on the outer surface 17a of the resin section 17 constitutes the reflective surface 3Ba that reflects light.

[0024] The glass film 21 is made of glass material and is formed on the surface of the metal film 19 on both the outer surface 17a and the inner surface 17b of the resin part 17. The glass film 21 has the function of increasing the rigidity (strength) of the resin part 17 by appropriately adjusting its thickness and hardness. The glass film 21 also functions as a protective film to improve heat resistance, abrasion resistance, chemical resistance, insulation, corrosion resistance, etc. The glass film 21 is an oxide glass mainly composed of SiO2, and may contain oxides such as Al2O3, TiO2, and ZrO2 as needed. The glass film 21 is formed, for example, by vapor deposition. In vapor deposition, the glass material and the resin part 17 on which the metal film 19 is formed are placed in a container, the container is evaporated, and the glass material is heated. The glass material that evaporates (vaporizes) due to heating adheres to the surface of the metal film 19 on the resin part 17, forming the glass film 21. Methods for heating glass materials include, for example, resistance heating, electron beam heating, high-frequency induction heating, and laser heating.

[0025] The metal film 19 and the glass film 21 are formed on all surfaces of the resin part 17. That is, as shown in Figure 5, the metal film 19 and the glass film 21 are formed not only on the outer surface 17a and the inner surface 17b of the resin part 17 in the reflective part 3B, but also on the lower end surface 17c of the resin part 17 in the reflective part 3B. Furthermore, as shown in Figure 6, the metal film 19 and the glass film 21 are also formed on the surface of the connecting part 3A of the polygonal mirror 3. That is, the metal film 19 and the glass film 21 are formed on the outer (upper) surface, the inner (lower) surface, the inner circumferential surface of the shaft hole 3a, and the inner circumferential surface of the through hole 3b of the resin part 17 in the connecting part 3A.

[0026] Furthermore, the thickness of the glass film 21 may be varied depending on the part of the resin part 17, depending on factors such as the shape of the resin part 17, the thickness of the resin part 17 or the metal film 19, the material (composition, etc.) of the resin part 17 or the metal film 19, the operating environment of the polygonal mirror 3 (temperature changes, etc.), the external forces acting on the polygonal mirror 3 (centrifugal force, torsional force, bending force, etc.), and the specifications required for the polygonal mirror 3 (required precision, etc.). For example, the thickness of the glass film 21 may be different on the outer surface 17a and the inner surface 17b of the resin part 17 in the reflective part 3B. For example, if it is preferable to increase the rigidity of the outer surface 17a side compared to the inner surface 17b side due to the factors mentioned above, the deformation of the resin part 17 can be better prevented by making the thickness of the glass film 21 on the outer surface 17a side thicker than that on the inner surface 17b side. Conversely, if it is preferable to increase the rigidity of the inner surface 17b side compared to the outer surface 17a side, the deformation of the resin part 17 can be better prevented by making the thickness of the glass film 21 on the inner surface 17b side thicker than that on the outer surface 17a side. In this way, by varying the thickness of the glass film 21 depending on the part, the rigidity (strength) of the resin part 17 can be appropriately adjusted according to the required specifications.

[0027] The thickness of the glass film 21 can be adjusted, for example, by changing the film deposition time during vapor deposition. Alternatively, it may be adjusted by changing the deposition rate per unit time, for example, by adjusting the power applied to the metal film or the heating temperature of the glass material.

[0028] Furthermore, glass films are generally strong in compression but weak in tension, bending, and twisting. For this reason, it is preferable to increase the density and hardness of areas where external forces act and strain occurs to improve rigidity. However, if the hardness is increased in areas where tensile, bending, or twisting forces act, cracks may occur and the film may break easily. Therefore, it is preferable to adjust the hardness appropriately to improve flexibility. Accordingly, for example, the hardness of the glass film 21 may be made different depending on the area of ​​the resin part 17, depending on the factors described above. For example, the hardness of the glass film 21 may be made different on the outer surface 17a and the inner surface 17b of the resin part 17 in the reflective part 3B. In the box-shaped polygonal mirror 3 of this embodiment, due to the centrifugal force acting on each reflective part 3B, a tensile force acts on the outer surface 17a side and a compressive force acts on the inner surface 17b side of the resin part 17 in the reflective part 3B. In such cases, by adjusting the hardness of the glass film 21 on the outer surface 17a and the inner surface 17b of the resin part 17 to balance the tensile and compressive forces, the rigidity (strength) of the resin part 17 can be improved while preventing damage to the glass film 21. In this way, by changing the hardness of the glass film 21 according to the part, the rigidity (strength) of the resin part 17 can be appropriately adjusted according to the required specifications.

[0029] The hardness of the glass film 21 can be adjusted by its composition. For example, increasing the content of network-forming oxides such as SiO2 and Al2O3 strengthens the network structure of the glass film 21 and increases its hardness. Conversely, increasing the content of network-modifying oxides such as Na2O, K2O, and CaO relaxes the network structure of the glass film 21 and decreases its hardness.

[0030] (Manufacturing procedure for polygonal mirrors) Figure 7 is a flowchart showing an example of the manufacturing procedure for the polygonal mirror 3 according to the first embodiment.

[0031] As shown in Figure 7, in step S10, molten resin material is injected into a mold and a resin part 17 is formed by injection molding or compression molding, which has a connection part 3A with the motor 5 and a reflective part 3B having an outer surface 17a into which light 7i is incident and an inner surface 17b into which light 7i is not incident. Step S10 is an example of the first step.

[0032] In step S20, a metal film 19 made of a metallic material is formed on all surfaces of the resin portion 17 formed in step S10, including both the outer surface 17a and the inner surface 17b of the reflective portion 3B, by film deposition. Step S20 is an example of the second step.

[0033] In step S30, a glass film 21 made of glass material is formed on all surfaces of the metal film 19 formed in step S20, including the surface of the connecting portion 3A and both the outer surface 17a and the inner surface 17b of the reflective portion 3B. In step S30, the glass film 21 may be formed with different thicknesses on the outer surface 17a side and the inner surface 17b side of the reflective portion 3B. In step S30, the glass film 21 may be formed with different hardnesses on the outer surface 17a side and the inner surface 17b side of the reflective portion 3B. Step S30 is an example of the third step.

[0034] (Effects of the first embodiment) As described above, the polygonal mirror 3 according to the first embodiment has a resin part 17, a metal film 19, and a glass film 21, and is rotated or oscillated around the rotation axis AX. The metal film 19 is formed on the outer surface 17a of the resin part 17, and the incident light 7i is reflected by the metal film 19 and scanned. Since the base resin part 17 of the polygonal mirror 3 can be formed by injection molding or compression molding, precision machining by cutting, as is required when using metal materials for the base shape, is unnecessary, and the time required for manufacturing can be significantly reduced. Therefore, productivity can be improved and costs can be reduced.

[0035] Furthermore, in the first embodiment, glass films 21 are formed on both the outer surface 17a and the inner surface 17b of the resin part 17. This allows the glass films 21 on both sides to suppress bending and twisting of the resin part 17 due to external forces such as centrifugal force, thereby preventing deformation of the resin part 17. Also, for example, as shown in Figure 8(a), if a metal film 19 and a glass film 21 are formed on the outer surface 17a of the resin part 17, but not on the inner surface 17b, then due to the difference in thermal expansion coefficients between the resin part 17 and the glass film 21, bending occurs at high temperatures as the resin part 17 expands more than the glass film 21, as shown in Figure 8(b), and bending occurs at low temperatures as the resin part 17 contracts more than the glass film 21, as shown in Figure 8(c). In contrast, in the first embodiment, as shown in Figure 9, since the glass film 21 is formed on both the outer surface 17a and the inner surface 17b of the resin part 17, deformation such as deflection due to temperature changes caused by the difference in thermal expansion coefficients between the resin part 17 and the glass film 21 can be suppressed by the glass films 21 on both sides, thereby preventing deformation of the resin part 17. In this way, the rigidity of the polygonal mirror 3 can be improved, and the shape stability against temperature changes can be improved, so that the accuracy of the reflective surface 3Ba can be ensured. The accuracy of the reflective surface 3Ba includes, for example, the surface accuracy of the reflective surface 3Ba, the angular accuracy of the reflective surface 3Ba, and the runout accuracy during rotation.

[0036] Furthermore, by covering the entire resin part 17 and metal film 19 with the glass film 21, it is possible to improve heat resistance, the insulating and corrosion-resistant properties of the metal film 19, and the chemical resistance of the resin part 17 to gases such as chlorine and hydrogen sulfide.

[0037] Furthermore, since light does not normally enter the inner surface 17b of the resin part 17, there is no need to form a metal film 19 on the inner surface 17b. However, if a metal film 19 is formed only on the outer surface 17a where light 7i enters, the force generated by the difference in thermal expansion coefficients between the resin part 17 and the metal film 19 will be unbalanced between the outer surface 17a and the inner surface 17b. In the first embodiment, since the metal film 19 is formed on both the outer surface 17a and the inner surface 17b of the resin part 17, the force generated by the difference in thermal expansion coefficients can be balanced between the outer surface 17a and the inner surface 17b of the resin part 17. As a result, in synergy with the strength improvement provided by the glass film 21, minute deformation can be further prevented, and the accuracy of the reflective surface 3Ba can be further improved.

[0038] Furthermore, since the polygonal mirror 3 is rotationally driven by the motor 5, external forces such as torsional force (torque) and bending force act on the connection part 3A with the motor 5, in addition to centrifugal force. If deformation such as deflection or twisting occurs in the connection part 3A, it may affect the reflective surface 3Ba. In the first embodiment, since the glass film 21 is also formed on the surface of the connecting portion 3A, the rigidity of the entire resin portion 17, including the connecting portion 3A, can be improved. Therefore, the accuracy of the reflective surface 3Ba can be further improved.

[0039] (Modification of the first embodiment) The present invention is not limited to the first embodiment described above, and various modifications are possible without departing from its spirit and technical concept.

[0040] In the first embodiment described above, the metal film 19 and the glass film 21 were formed on both the outer surface 17a and the inner surface 17b of the resin part 17. However, as shown in Figure 10, for example, the metal film 19 may be formed only on the outer surface 17a of the resin part 17 into which the light 7i is incident, and not on the inner surface 17b or the lower end surface 17c. Furthermore, the metal film 19 may not be formed on the surface of the connecting part 3A. In other words, in this modified example, the metal film 19 may be formed only on the outer surface (reflective surface 3Ba) of the reflective part 3B into which the light 7i is incident. In this modified example, the glass film 21 is formed on the entire surface of the resin part 17, but it may be formed only on the surface of the metal film 19. Furthermore, the glass film 21 may be formed only on both the outer surface 17a and the inner surface 17b of the resin part 17 in the reflective part 3B.

[0041] <Second Embodiment> The second embodiment is an embodiment in which the rotating mirror is a cylindrical mirror. A cylindrical mirror is a mirror whose reflective surface is an inclined plane formed on a cylindrical rotating body. The second embodiment will be described with reference to Figures 11 and 12.

[0042] (Construction of cylindrical mirror unit and cylindrical mirror) Figure 11 is a perspective view showing an example of the overall configuration of a cylindrical mirror unit comprising a cylindrical mirror and a motor according to the second embodiment.

[0043] As shown in Figure 11, the cylindrical mirror unit 23 includes a cylindrical mirror 25 that rotates around a rotation axis AX and scans by reflecting incident light 7i, and a motor 27 that rotates the cylindrical mirror 25 around the rotation axis AX. The cylindrical mirror 25 is formed in a cylindrical shape with an inclined plane at its upper end.

[0044] The cylindrical mirror 25 (an example of a rotating mirror) has a cylindrical portion 25A (an example of a connecting portion) that constitutes the connection portion with the motor 27, and a reflective portion 25B formed at the upper end of the cylindrical portion 25A and inclined with respect to the rotation axis AX, and is formed in a substantially cylindrical shape with an open bottom. The reflective portion 25B is a substantially elliptical plate-like member and is connected to the upper end of the cylindrical portion 25A. The outer (upper) surface of the reflective portion 25B constitutes a reflective surface 25Ba that reflects incident light 7i. Light 7i emitted from a light source (not shown) is incident on the reflective surface 25Ba of the cylindrical mirror 25 and reflected. When the cylindrical mirror 25 rotates around the rotation axis AX, the direction of propagation of the reflected light 7o rotates around the rotation axis AX over time in accordance with the rotation of the reflective surface 25Ba, and the reflected light 7o is scanned over a predetermined area. Note that while Figure 11 illustrates the case where light 7i is incident at a position and direction that coincides with the rotation axis AX, light 7i may also be incident at a position that does not coincide with the rotation axis AX, and it does not have to be parallel to the rotation axis AX.

[0045] A motor 27 (an example of a drive device) is positioned below the cylindrical mirror 25 and rotates the cylindrical mirror 25 around the rotation axis AX. The motor 27 may continuously rotate the cylindrical mirror 25 in a predetermined rotational direction (for example, arrow 13 in Figure 11), change the rotational direction and rotate it back and forth, or oscillate it within a predetermined angular range. A disc-shaped support member 29 is fixed to the output shaft (not shown) of the motor 27. The support member 29 rotates together with the output shaft. The cylindrical mirror 25 is fixed to the upper part of the support member 29.

[0046] (Membrane structure of cylindrical mirrors) Figure 12 is a cross-sectional view corresponding to the XII-XII section in Figure 11, showing an example of the cross-sectional and film configuration of a cylindrical mirror according to the second embodiment. As shown in Figure 12, the cylindrical mirror 25 has a resin part 31, a metal film 33, and a glass film 35. The resin part 31 is made of a resin material and constitutes the base shape of the cylindrical mirror 25. The resin part 31 has an outer (upper) surface 31a (an example of a first surface) into which light 7i is incident, and an inner (lower) surface 31b (an example of a second surface) located on the opposite side of the outer surface 31a in the direction of incidence of light 7i, and into which light 7i is not incident. The resin material is the same as in the first embodiment described above. The surface of the resin part 31 is subjected to a surface modification treatment to improve adhesion with the metal film 33.

[0047] The metal film 33 is made of a metal material and is formed between the resin part 31 and the glass film 35 on both the outer surface 31a and the inner surface 31b of the resin part 31. The metal material and formation method of the metal film 33 are the same as in the first embodiment described above. In the reflective part 25B of the cylindrical mirror 25, the metal film 33 formed on the outer surface 31a of the resin part 31 constitutes the reflective surface 25Ba that reflects light.

[0048] The glass film 35 is made of glass material and is formed on the surface of the metal film 33 on both the outer surface 31a and the inner surface 31b of the resin part 31. The glass film 35 has the function of increasing the rigidity (strength) of the resin part 31 by appropriately adjusting its thickness and hardness. The glass material and formation method of the glass film 35 are the same as those of the first embodiment described above.

[0049] The metal film 33 and the glass film 35 are formed on all surfaces of the resin portion 31. That is, as shown in Figure 12, the metal film 33 and the glass film 35 are formed not only on the outer surface 31a and the inner surface 31b of the resin portion 31 in the reflective portion 25B of the cylindrical mirror 25, but also on the surface of the cylindrical portion 25A of the cylindrical mirror 25. Specifically, the metal film 33 and the glass film 35 are also formed on the outer surface 31c, the inner surface 31d, and the lower end surface 31e of the resin portion 31 in the cylindrical portion 25A.

[0050] In the second embodiment, as in the first embodiment described above, the thickness of the glass film 35 may be varied depending on the part of the resin part 31, depending on factors such as the shape of the resin part 31, the thickness of the resin part 31 or the metal film 33, the material (composition, etc.) of the resin part 31 or the metal film 33, the operating environment of the cylindrical mirror 25 (temperature changes, etc.), the external forces acting on the cylindrical mirror 25 (centrifugal force, torsional force, bending force, etc.), and the specifications required for the cylindrical mirror 25 (required precision, etc.). For example, the thickness of the glass film 35 may be different on the outer surface 31a and the inner surface 31b of the resin part 31 in the reflective part 25B. By varying the thickness of the glass film 35 depending on the part, the rigidity (strength) of the resin part 31 can be appropriately adjusted according to the required specifications, etc.

[0051] Furthermore, depending on the factors mentioned above, the hardness of the glass film 35 may be varied depending on the location of the resin part 31. For example, the hardness of the glass film 35 may be different on the outer surface 31a and the inner surface 31b of the resin part 31 in the reflective part 25B. By changing the hardness of the glass film 35 according to the location, the rigidity (strength) of the resin part 31 can be appropriately adjusted according to the required specifications.

[0052] The manufacturing procedure for the cylindrical mirror 25 is the same as that of the first embodiment described above, so a description will be omitted. The same effects as those of the first embodiment can be obtained in the second embodiment as well.

[0053] In the second embodiment described above, the metal film 33 and the glass film 35 were formed on both the outer surface 31a and the inner surface 31b of the resin part 31. However, the metal film 33 may be formed only on the outer surface 31a of the resin part 31 into which the light 7i is incident, and not on the inner surface 31b. Furthermore, the metal film 33 may not be formed on the surface of the cylindrical part 25A. In other words, in this modified example, the metal film 33 may be formed only on the outer surface of the reflective part 25B into which the light 7i is incident. In this modified example, the glass film 35 is formed on the entire surface of the resin part 31, but it may be formed only on the surface of the metal film 33. Furthermore, the glass film 35 may be formed only on both the outer surface 31a and the inner surface 31b of the resin part 31 in the reflective part 25B.

[0054] <Third Embodiment> The third embodiment is an embodiment in which the rotating mirror is a flat-plate type mirror. Examples of flat-plate type mirrors include, for example, galvanometer mirrors. The third embodiment will be described with reference to Figures 13 and 14.

[0055] (Configuration of flat-panel mirror unit and flat-panel mirror) Figure 13 is a perspective view showing an example of the overall configuration of a flat-plate mirror unit equipped with a flat-plate mirror and a motor according to the third embodiment.

[0056] As shown in Figure 13, the flat-plate mirror unit 37 includes a flat-plate mirror 39 that rotates around a rotation axis AX and scans by reflecting incident light, and a motor 41 that rotates the flat-plate mirror 39 around the rotation axis AX. The flat-plate mirror 39 is formed in a roughly rectangular flat shape.

[0057] The flat-plate mirror 39 (an example of a rotating mirror) is connected to the output shaft 41A of the motor 41 and also serves as the connection point to the motor 41. One side (upper side) of the flat-plate mirror 39 forms a reflective surface 39a that reflects incident light 7i. Light 7i emitted from a light source (not shown) is incident on the reflective surface 39a of the flat-plate mirror 39 and reflected. As the flat-plate mirror 39 rotates around the rotation axis AX, the direction of propagation of the reflected light 7o rotates around the rotation axis AX over time in accordance with the rotation of the reflective surface 39a, and the reflected light 7o is scanned over a predetermined area.

[0058] A motor 41 (an example of a drive device) is positioned to the side of the flat-plate mirror 39 and rotates the flat-plate mirror 39 around the rotation axis AX. The motor 41 may continuously rotate the flat-plate mirror 39 in a predetermined rotational direction (for example, arrow 13 in Figure 13), change the rotational direction and rotate it back and forth, or oscillate it within a predetermined angular range. The flat-plate mirror 39 is fixed to the tip of the output shaft 41A of the motor 41, and the flat-plate mirror 39 rotates together with the output shaft 41A.

[0059] (Film composition of a flat mirror) Figure 14 is a cross-sectional view corresponding to the XIV-XIV section in Figure 13, showing an example of the cross-sectional and film configuration of a flat-plate mirror according to the third embodiment. As shown in Figure 14, the flat mirror 39 has a resin part 43, a metal film 45, and a glass film 47. The resin part 43 is made of a resin material and constitutes the base shape of the flat mirror 39. The resin part 43 has a surface 43a (an example of a first surface) on one side (upper side) into which light 7i is incident, and a surface 43b (an example of a second surface) on the other side (lower side) located opposite the surface 43a in the direction of incidence of light 7i, and into which light 7i is not incident. The resin material is the same as in the first embodiment described above. The surface of the resin part 43 is subjected to a surface modification treatment to improve adhesion with the metal film 45.

[0060] The metal film 45 is made of a metal material and is formed between the resin part 43 and the glass film 47 on both surfaces 43a and 43b of the resin part 43. The metal material and formation method of the metal film 45 are the same as in the first embodiment described above. In the flat mirror 39, the metal film 45 formed on the surface 43a of the resin part 43 constitutes the reflective surface 39a that reflects light.

[0061] The glass film 47 is made of glass material and is formed on the surface of the metal film 45 on both the surface 43a and the surface 43b of the resin part 43. The glass film 47 has the function of increasing the rigidity (strength) of the resin part 43 by appropriately adjusting its thickness and hardness. The glass material and formation method of the glass film 47 are the same as those of the first embodiment described above.

[0062] The metal film 45 and the glass film 47 are formed on all surfaces of the resin portion 43. That is, as shown in Figure 14, the metal film 45 and the glass film 47 are formed not only on the outer surface 43a and the inner surface 43b of the resin portion 43 of the flat mirror 39, but also on the lateral (edge) end surface 43c.

[0063] In the third embodiment, as with the first and second embodiments described above, the thickness of the glass film 47 may be varied depending on the part of the resin part 43, depending on factors such as the shape of the resin part 43, the thickness of the resin part 43 or the metal film 45, the material (composition, etc.) of the resin part 43 or the metal film 45, the operating environment of the flat mirror 39 (temperature changes, etc.), external forces acting on the flat mirror 39 (centrifugal force, torsional force, bending force, etc.), and the specifications required for the flat mirror 39 (required precision, etc.). For example, the thickness of the glass film 47 may be different on one side surface 43a and the other side surface 43b of the resin part 43. By varying the thickness of the glass film 47 depending on the part, the rigidity (strength) of the resin part 43 can be appropriately adjusted according to the required specifications, etc.

[0064] Furthermore, depending on the factors mentioned above, the hardness of the glass film 47 may be varied depending on the location on the resin part 43. For example, the hardness of the glass film 47 may be different on one surface 43a and the other surface 43b of the resin part 43. By varying the hardness of the glass film 47 depending on the location, the rigidity (strength) of the resin part 43 can be appropriately adjusted according to the required specifications.

[0065] The manufacturing procedure for the flat-plate mirror 39 is the same as that of the first embodiment described above, so a description will be omitted. The same effects as those of the first embodiment described above can be obtained in the third embodiment as well.

[0066] In the third embodiment described above, the metal film 45 and the glass film 47 were formed on both surfaces 43a and 43b of the resin part 43. However, the metal film 45 may be formed only on the surface 43a of the resin part 43 into which the light 7i is incident, and not on the other surface 43b or the end face 43c. In other words, in this modified example, the metal film 45 may be formed only on the surface 43a of the flat mirror 39 into which the light 7i is incident. In this modified example as well, the glass film 47 is formed on the entire surface of the resin part 43, but it may be formed only on the surface of the metal film 45. Alternatively, the glass film 47 may be formed only on both surfaces 43a and 43b of the resin part 43.

[0067] In addition to what has already been described above, the methods according to each embodiment and the methods according to the modified versions may be used in appropriate combinations.

[0068] Furthermore, although not to be exemplified individually, the present invention may be implemented with various modifications without departing from its spirit. [Explanation of Symbols]

[0069] 1. Polygonal mirror unit 3. Polygonal mirror (an example of a rotating mirror) 3A connection part 3B Reflector 3Ba reflective surface 5. Motor (an example of a drive device) 7i light 7o reflected light 17 Resin part 17a Outer surface (an example of the first surface) 17b Inner surface (an example of the second surface) 19 Metal film 21 Glass film 23 Cylindrical Mirror Unit 25. Cylindrical mirror (an example of a rotating mirror) 25A Cylindrical section (an example of a connecting section) 25B Reflector 25Ba reflective surface 27. Motor (an example of a drive device) 31 Resin part 31a Outer surface (an example of the first surface) 31b Inner surface (an example of the second surface) 33 Metal film 35 Glass film 37 Flat-plate mirror unit 39. Flat-type mirror (rotating mirror, example of a connecting part) 39a Reflective surface 41. Motor (an example of a drive device) 43 Resin part 43a One side surface (an example of the first surface) 43b The other side surface (an example of the second surface) 45 Metal film 47 Glass film AX rotation axis

Claims

1. A rotating mirror that rotates or oscillates around a rotation axis and scans by reflecting incident light, A resin part made of a resin material, having a first surface onto which the light is incident, and a second surface located on the opposite side of the first surface in the direction of light incidence and not onto which the light is incident, A glass material is used, and glass films are formed on both the first and second surfaces, A metal film is formed between the resin portion and the glass film on at least the first of the first and second surfaces, which is made of a metal material. A rotating mirror having

2. The aforementioned metal film is On both the first and second surfaces, a layer is formed between the resin portion and the glass film. The rotating mirror according to claim 1.

3. The aforementioned resin part is It is equipped with a connection to a drive device that rotates the aforementioned rotating mirror, The aforementioned glass film is The surface of the aforementioned connecting portion is also formed, The rotating mirror according to claim 1.

4. The aforementioned glass film is The thickness differs between the first surface and the second surface. A rotating mirror according to any one of claims 1 to 3.

5. The aforementioned glass film is The hardness differs between the first surface and the second surface. A rotating mirror according to any one of claims 1 to 3.

6. A method for manufacturing a rotating mirror that rotates or oscillates around a rotation axis and scans by reflecting incident light, A first step involves injecting molten resin material into a mold to form a resin portion having a first surface onto which the light is incident, and a second surface located on the opposite side of the first surface in the direction of light incidence and not onto which the light is incident. A second step of forming a metal film made of a metallic material on at least the first of the first and second surfaces, A third step involves forming a glass film made of glass material on both the first and second surfaces, A method for manufacturing a rotating mirror, comprising:

7. In the second step described above, The metal film is formed on both the first and second surfaces. A method for manufacturing a rotating mirror according to claim 6.

8. In the first step described above, The resin part is formed to include a connection portion with a drive device that rotates the aforementioned rotating mirror, In the above third step, The glass film is also formed on the surface of the connecting portion. A method for manufacturing a rotating mirror according to claim 6.

9. In the above third step, The glass film is formed such that the thickness differs between the first surface and the second surface. A method for manufacturing a rotating mirror according to any one of claims 6 to 8.

10. In the above third step, The glass film is formed such that the hardness differs between the first surface and the second surface. A method for manufacturing a rotating mirror according to any one of claims 6 to 8.

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