Distance measuring device

Abstract

To provide a distance measuring device with which a dispersion in mirror face position is suppressible.SOLUTION: The distance measuring device comprises: a spindle 13 for scanning light to the outside and detecting light reflected from an object, thereby measuring the distance to the object, and driven by a shaking motor; a mirror 18 for scanning light to the outside and swing driven by the shaking motor; and a holder 21. The holder 21 includes a press-in part 31 in which a hole 311 is formed for the spindle 13 to be pressed-in, and a mirror holding part 32 formed integrally with the press-in part 31, and to which the mirror 18 is pasted by an adhesive member 29. A mirror contact part 41 protruding to the mirror 18 side and coming into contact with the mirror 18 is formed in the mirror holding part 32.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a distance measuring device. [Background technology]

[0002] Distance measuring devices are known that detect the distance to an object by irradiating a transmission wave and detecting the reflected wave from the object. An optical scanning device is used in distance measuring devices, and for example, the optical scanning device disclosed in Patent Document 1 scans light by rotating a mirror back and forth. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-96295 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, a plate-shaped mirror is attached to one surface of a substrate. When attaching the mirror to a holding member such as a substrate using adhesive or double-sided tape, it is difficult to adjust the thickness of the material used for adhesion, and there is a risk that variations in thickness will affect distance measurement accuracy.

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a distance measuring device capable of suppressing the variation in the mirror surface position. [Means for solving the problem]

[0006] The distance measuring device of the present invention measures the distance to an object by scanning light externally and detecting the light reflected by the object, and is equipped with an oscillating shaft (13) driven by an actuator (50), a mirror (18) that is oscillated by the actuator to scan light externally, and holders (21-28).

[0007] The holder has a shaft holding part (31) in which a hole part (311) into which the oscillating shaft is press-fitted is formed, and a mirror holding part (32, 33) which is formed integrally with the shaft holding part and to which the mirror is attached with an adhesive member (29). The mirror holding part has a mirror abutment part which protrudes toward the mirror and abuts against the mirror. This makes it possible to suppress variation in the position of the mirror surface. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view showing a swing actuator of the distance measuring device according to the first embodiment. [Diagram 2] FIG. 2 is a perspective view showing a spindle, a holder, and a mirror according to the first embodiment. [Diagram 3] FIG. 2 is a plan view showing the holder according to the first embodiment. [Figure 4] 4 is a view taken in the direction of the arrow IV in FIG. 3. [Diagram 5] FIG. 4 is an enlarged view of the fourth V portion. [Figure 6] FIG. 11 is a plan view showing a holder according to a second embodiment. [Figure 7] FIG. 11 is a plan view showing a holder according to a third embodiment. [Figure 8] FIG. 13 is a plan view showing a holder according to a fourth embodiment. [Figure 9] FIG. 13 is a plan view showing a holder according to a fifth embodiment. [Figure 10] 10 is a view taken in the direction of the arrow X in FIG. 9. [Figure 11] FIG. 13 is a plan view showing a holder according to a sixth embodiment. [Figure 12] 12 is a view taken in the direction of the arrow XII in FIG. 11. [Figure 13] FIG. 13 is a plan view showing a holder according to a seventh embodiment. [Figure 14] 14 is a view taken in the direction of the arrow XIV in FIG. 13. [Figure 15] FIG. 13 is a plan view showing a holder according to an eighth embodiment. [Figure 16] FIG. 16 is a view taken in the direction of the arrow XVI in FIG. [Figure 17]FIG. 1 is a schematic diagram showing a distance measuring device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A distance measuring device according to the present invention will now be described with reference to the drawings. In the following, in a number of embodiments, substantially the same components are designated by the same reference numerals, and description thereof will be omitted.

[0010] (First embodiment) The first embodiment is shown in Fig. 1 to Fig. 5. Also, a schematic configuration of a distance measuring device is shown in Fig. 17. As shown in Fig. 17, the distance measuring device 1 is a LiDAR (Light Detection and Ranging) device that measures the distance to an object by irradiating light and detecting reflected light from the object onto which the light is irradiated. The distance measuring device 1 is mounted on, for example, a vehicle and used to detect an object present in front of the vehicle.

[0011] The distance measuring device 1 includes a light emitting unit 91, a light receiving unit 92, and a swing actuator 5, and is housed in a housing 93. The light emitting unit 91 intermittently outputs a light beam B. The output light beam B is reflected by a mirror 18 that is driven to swing, and is emitted to the outside through an optical window 94. The light receiving unit 92 receives the reflected light from an object irradiated with the light beam B. The light detected by the light receiving unit 92 is converted into an electrical signal, and is used to calculate the distance to the object.

[0012] As shown in Fig. 1, the oscillation actuator 5 includes a mirror section 10, an oscillation motor 50, and an encoder 60. The mirror section 10 includes a base 11, a spindle 13, a mirror 18, and a holder 21. The base 11 includes an attachment section 111 and holding walls 112 and 113, and is integrally formed from, for example, metal. The attachment section 111 is attached to a housing by bolts or the like. The holding walls 112 and 113 are provided substantially vertically on both ends of the attachment section 111.

[0013] The spindle 13 is disposed substantially parallel to the mounting portion 111, and is rotatably held on the base 11 by bearings 14, 15 provided on the retaining walls 112, 113. The bearings 14, 15 in this embodiment are ball bearings, but bearings other than ball bearings may be used. The spindle 13 is formed to extend to the swing motor 50 and the encoder 60. Hereinafter, the axis of the spindle 13 is referred to as the swing axis Ax, and the swing axis direction is simply referred to as the "axial direction". In addition, in the configuration of the holder 21, etc., the side closer to the swing axis Ax is referred to as the inner side in the swing direction, and the far side is referred to as the outer side. The E-ring 16 is provided on the outer side of the bearing 14 in the axial direction, and functions as a retainer for the spindle 13.

[0014] 1 and 2, the mirror 18 is formed in a rectangular flat plate shape in a plan view, and is attached to the holder 21 so as to be symmetrical about the oscillation axis Ax. The mirror 18 may have a shape other than a rectangle as long as it is symmetrical about the oscillation axis Ax. The holder 21 and the mirror 18 are disposed inside the base 11 so that the mirror surface 181 faces the opposite side to the mounting portion 111, and are driven to oscillate by the oscillation motor 50. The mirror 18 reflects the light beam B output from the light emitting portion 91 on the mirror surface 181, and emits the light beam B to the outside in a direction according to the oscillation position of the mirror 18, thereby scanning the light beam within a preset scanning range.

[0015] The holder 21 has a press-fit portion 31 and a mirror holding portion 32, and is integrally formed from, for example, metal. A hole 311 through which the spindle 13 is inserted is formed in the press-fit portion 31, and the spindle 13 is press-fitted and fixed. The press-fit portion 31 protrudes further from the mirror holding portion 32 on the opposite side to the mirror 18. In other words, the plate thickness of the mirror holding portion 32 is smaller than that of the press-fit portion 31.

[0016] The mirror 18 is attached to the mirror holding portion 32 by adhesive or the like on a mirror mounting surface, which is the surface opposite to the surface from which the press-fit portion 31 protrudes. The mirror holding portions 32 are formed symmetrically with respect to the swing axis Ax on both sides of the press-fit portion 31. This allows the moment of inertia during swing to be equal in both directions. The axial length of the mirror holding portion 32 is longer than that of the press-fit portion 31, and the holder 21 is formed generally in a substantially H-shape in plan view. By making the axial length of the press-fit portion 31 shorter than that of the mirror holding portion 32, the holder 21 can be made lighter while ensuring a mounting area for the mirror 18. Details of mounting the mirror 18 to the holder 21 will be described later.

[0017] 1, the oscillation motor 50 is provided on one side in the axial direction of the mirror unit 10. The oscillation motor 50 has a stator 51, a rotor magnet 52, a preload spring 54, etc. The stator 51 is fixed to the retaining wall 113 with bolts or the like. The stator 51 is provided with an electromagnetic coil and a fixed magnet (not shown).

[0018] Rotor magnet 52 is formed in a cylindrical shape with an axial hole 521 provided at the center, is inserted into spindle 13, and is fixed to spindle 13 by rotor fixing member 53. One end of preload spring 54 abuts against bearing 15, and the other end abuts against rotor magnet 52.

[0019] The rotor magnet 52 is disposed inside the stator 51, and oscillates around a stationary position when current is applied to the electromagnetic coil. Here, the oscillating motion is a motion that periodically repeats forward and reverse rotations within a predetermined angular range less than 360°. When current is turned off to the electromagnetic coil, the rotor magnet 52 returns to the stationary position and becomes stationary due to the magnetic force of the fixed magnet.

[0020] The encoder 60 has a disk 61 and a detection element 63, and is housed in a case 65. The disk 61 is attached to a disk hub (not shown) that is press-fitted and fixed to the encoder 60 side of the spindle 13, and rotates integrally with the spindle 13. The detection element 63 is mounted on a substrate 64, and detects the rotational position of the disk 61. This enables the encoder 60 to detect the oscillation positions of the oscillation motor 50 and the mirror 18. A through hole 641 is formed in the substrate 64, and the spindle 13 is inserted therethrough.

[0021] In this embodiment, the mirror 18 is attached to the holder 21 using an adhesive member 29 (see FIG. 5) such as an adhesive or double-sided tape. When the mirror 18 is attached using the adhesive member 29, it is difficult to adjust the thickness of the adhesive member 29, and therefore there is a risk that the distance between the mirror surface 181 and the spindle 13 will vary.

[0022] Furthermore, when the spindle 13 is press-fitted into the hole 311 of the holder 21, the press-fit portion 31 may bulge toward the mirror 18. If the holder 21 bulges due to the press-fitting, the surface precision of the mirror mounting surface may deteriorate, which may cause variation in the distance between the mirror surface 181 and the spindle 13. Variation in the distance between the mirror surface 181 and the spindle 13 affects the distance measurement precision.

[0023] In this embodiment, as shown in Figs. 3 to 5, a mirror abutment portion 41 that abuts against the mirror 18 at its tip end is formed on the surface of the holder 21 on the mirror 18 side. In this embodiment, the mirror abutment portion 41 is formed to extend in the axial direction along the end of the press-fit portion 31 side of the mirror holding portion 32. The protruding height of the mirror abutment portion 41 is set to a height (for example, about 0.1 mm) that can ensure the necessary mounting strength when mounting the mirror with the adhesive member 29. The adhesive member 29 is provided on the outside of the mirror abutment portion 41, and the mirror 18 is attached to it. The mirror abutment portion 41 abuts against the mirror 18 to regulate the thickness of the adhesive member 29. In Fig. 5, the adhesive member 29 is shown with a matte finish for the sake of explanation. The same applies to Fig. 10 and the like.

[0024] Moreover, by forming the mirror abutment portion 41 at the end portion on the press-fit portion 31 side, the mirror abutment portion 41 functions as a regulating wall that prevents the adhesive member 29 from flowing out to the press-fit portion 31 side. The holder 21 and the mirror 18 are abutted at the mirror abutment portion 41, and the mirror 18 and the holder 21 are bonded at the mirror holding portion 32 provided on the outside of the press-fit portion 31, so that a gap is formed between the press-fit portion 31 and the mirror 18. As a result, even if the press-fit portion 31 is deformed by the press-fitting of the spindle 13, the expansion is absorbed by the gap, so that the press-fit portion 31 does not interfere with the mirror 18. As a result, it is possible to suppress the variation in the distance between the mirror surface 181 and the spindle 13, and it is possible to ensure the distance measurement accuracy.

[0025] As described above, the distance measuring device 1 measures the distance to an object by scanning light externally and detecting the light reflected by the object, and is equipped with a spindle 13 driven by an oscillating motor 50, a mirror 18 that is oscillated by the oscillating motor 50 to scan light externally, and a holder 21.

[0026] The holder 21 has a press-fitting portion 31 in which a hole 311 into which the spindle 13 is press-fitted is formed, and a mirror holding portion 32 which is formed integrally with the press-fitting portion 31 and to which the mirror 18 is affixed with an adhesive member 29. The mirror holding portion 32 has a mirror abutment portion 41 which protrudes towards the mirror 18 and abuts against the mirror 18.

[0027] In this embodiment, a protruding mirror abutment portion 41 is formed on the mirror mounting surface of the mirror holding portion 32, and the holder 21 and the mirror 18 are abutted at the mirror abutment portion 41 without the adhesive member 29, thereby suppressing variation in the distance between the mirror surface 181 and the oscillation axis Ax. In addition, by providing the mirror abutment portion 41 at a location other than the press-fit portion 31, it is possible to prevent deterioration in the surface accuracy of the mirror surface 181 due to deformation of the press-fit portion 31 caused by press-fitting the spindle 13. This ensures the positional accuracy of the mirror surface and improves distance measurement accuracy.

[0028] The press-fit portion 31 and the mirror holding portion 32 are separated by a mirror abutment portion 41. The mirror 18 is attached to the holder 21 by an adhesive member 29 provided on the mirror holding portion 32, and is separated from the press-fit portion 31. Since the adhesive member 29 is not provided on the press-fit portion 31, there is no need to consider the effect of the thickness of the adhesive member 29, and the press-fit portion 31 does not interfere with the mirror 18 even after press-fitting. This can further improve the distance measurement accuracy.

[0029] The length of the mirror holding portion 32 in the direction of the oscillation axis (that is, for example, the vertical direction on the paper in FIG. 3) is greater than that of the press-fit portion 31. This makes it possible to ensure a sufficient adhesion area with the mirror 18 regardless of the press-fit length.

[0030] Second embodiment The second embodiment is shown in FIG. 6. The second to eighth embodiments are different in the shape of the holder, and this point will be mainly described. In addition to the mirror abutment portion 41 formed on the press-fit portion 31 side, the mirror holding portion 32 of the holder 22 is also provided with a mirror abutment portion 42 on the outer side in the swing direction. The adhesive member 29 is provided between the mirror abutment portions 41 and 42, and the mirror 18 (not shown in FIG. 6 and other figures) is attached to the holder 22. The mirror abutment portions 41 and 42 are formed at the same height, and abut the mirror 18 at the tip surface. By forming the mirror abutment portion 42 on the outer side as well, it is possible to suppress deformation of the mirror 18 due to swing. In addition, it is possible to prevent the adhesive member 29 from protruding outward. In addition, the same effects as those of the above embodiment are achieved.

[0031] Third embodiment The third embodiment is shown in Fig. 7. A mirror abutment portion 43 is provided on the mirror holding portion 32 of the holder 23. The mirror abutment portion 43 is formed along the outer edge of the mirror holding portion 32. The adhesive member 29 is provided in an inner area surrounded by the mirror abutment portion 43, and the mirror 18 is attached to the holder 23. The holder 23 abuts against the mirror 18 at the tip surface of the mirror abutment portion 43. By providing the mirror abutment portion 43 along the outer edge of the mirror holding portion 32, deformation of the mirror 18 due to rocking can be suppressed. Also, protrusion of the adhesive member 29 can be prevented.

[0032] An opening 435 is formed in the mirror contact portion 43. In this embodiment, the opening 435 is formed on the press-fit portion 31 side and functions as an air vent during bonding and as an escape portion when the adhesive member 29 expands due to heat or the like. This makes it possible to suppress a decrease in distance measurement accuracy due to temperature changes or the like. Also, the same effects as those of the above embodiment are achieved.

[0033] (Fourth embodiment) The fourth embodiment is shown in Fig. 8. A mirror abutment portion 44 is provided on the mirror holding portion 32 of the holder 24. The mirror abutment portion 44 is formed along the end of the mirror holding portion 32 on the press-fit portion 31 side and both axial ends, and opens to the outside. The adhesive member 29 is provided in the area surrounded by the mirror abutment portion 44, and the mirror 18 is attached to the holder 24. This makes it possible to prevent the adhesive member 29 from flowing into the press-fit portion 31 side. It is also possible to suppress deformation of the mirror 18 due to rocking. Also, the same effects as those of the above embodiment are achieved.

[0034] Fifth embodiment 9 and 10 show the fifth embodiment. The holder 25 is integrally formed with a press-fit portion 31 and a mirror holding portion 33. The mirror holding portion 33 is formed in a generally rectangular shape in a plan view. The press-fit portion 31 is formed to protrude further toward the opposite side of the mirror 18 than the mirror holding portion 33. As in the above embodiments, the axial length of the press-fit portion 31 is shorter than that of the mirror holding portion 33. A groove portion 312 is formed on the surface of the mirror holding portion 33 opposite the mirror 18 so as not to interfere with the spindle 13 inserted through the hole portion 311.

[0035] A mirror abutment portion 45 is formed protruding from the surface of the holder 25 facing the mirror 18. The mirror abutment portion 45 is formed on the mirror mounting surface, extending in the axial direction along the outer side of the projection area of ​​the press-fit portion 31 in the swing direction. The adhesive member 29 is provided on the outer side of the mirror abutment portion 45, and the mirror 18 is attached to the holder 25. The mirror 18 abuts against the holder 25 at the tip surface of the mirror abutment portion 45. In this embodiment, the mirror 18 and the mirror holding portion 33 are spaced apart in the area where the press-fit portion 31 is formed. Even with this configuration, the same effects as the above embodiment can be achieved.

[0036] Sixth embodiment The sixth embodiment is shown in Figures 11 and 12. In the sixth embodiment, a mirror abutment portion 46 is formed protruding from the holder 26 on the outer side in the swing direction of the mirror mounting surface of the mirror holding portion 33. The adhesive member 29 is provided in an area sandwiched between the mirror abutment portions 46, and the mirror 18 is attached to the holder 26. The mirror 18 abuts against the holder 26 at the tip surface of the mirror abutment portion 46. By providing the mirror abutment portion 46 on the outer side in the swing direction, deformation of the mirror 18 due to swing can be suppressed. In addition, the same effects as those of the above embodiments can be achieved.

[0037] Seventh embodiment As shown in Figs. 13 and 14, the mirror abutment portion 47 in the holder 27 of the seventh embodiment is formed to protrude from the mirror mounting surface of the mirror holding portion 33. The mirror abutment portion 47 is formed along both ends in the axial direction (the upper end and the lower end of the paper surface in Fig. 13) at four locations outside the region in the swing direction from the region in which the press-fit portion 31 is extended in the axial direction. The adhesive member 29 is provided in the region on the mirror mounting surface side where the mirror abutment portion 47 is not formed, and the mirror 18 is attached to the holder 27. The mirror 18 abuts against the holder 27 at the tip surface of the mirror abutment portion 47. By forming the mirror abutment portion 47 on the axial outer side, it is possible to suppress deformation of the mirror 18 due to vibrations caused by swinging. In addition, the same effects as those of the above embodiment are achieved.

[0038] Eighth embodiment As shown in Figures 15 and 16, the mirror abutment portion 48 of the holder 28 in the eighth embodiment is formed outside the rocking direction of the portion where the press-fit portion 31 is formed, and protrudes into the middle region in the axial direction. The adhesive member 29 is provided in the region on the mirror mounting surface side where the mirror abutment portion 48 is not formed, and the mirror 18 is attached to the holder 28. The mirror 18 abuts against the holder 28 at the tip surface of the mirror abutment portion 48. This configuration also achieves the same effects as the above embodiment. Note that the adhesive member 29 is omitted in Figure 16 to avoid complication.

[0039] In the embodiment, the spindle 13 corresponds to the "oscillating shaft", the press-fit portion 31 corresponds to the "shaft holding portion", and the oscillating motor 50 corresponds to the "actuator".

[0040] (Other embodiments) In the above embodiment, the mirror contact portions are formed at two or four locations on the mirror mounting surface side of the holder. In other embodiments, the shape and number of the mirror contact portions may be different from those in the above embodiment.

[0041] In the above embodiment, the press-in portion is formed to protrude on the opposite side to the mirror mounting surface. In other embodiments, the shape of the press-in portion may be any shape, and for example, depending on the spindle diameter and the plate thickness of the holder, the press-in portion may not protrude and the press-in hole may be formed to penetrate the inside of the holder. In such a case, the area obtained by projecting the press-in hole in a direction perpendicular to the oscillation axis is regarded as the "shaft holding portion," and the outer area of ​​the shaft holding portion is regarded as the "mirror holding portion," and the mirror abutment portion may be formed at any point on the mirror holding portion.

[0042] The shapes of the holder and the mirror may be different from those of the above embodiment. It is preferable that the holder and the mirror are formed symmetrically with respect to the oscillation axis in order to equalize the moment of inertia during oscillation. Furthermore, the oscillation motor and the mirror unit may have different configurations and arrangements from those of the above embodiment as long as they can oscillate the mirror.

[0043] As described above, the present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. [Explanation of symbols]

[0044] 1... Distance measuring device 10. Mirror section 13 Spindle (oscillating shaft) 18. Mirror 21~28···Holder 29... Adhesive material 31 Press-fit portion (shaft holding portion) 32, 33: Mirror holder 41~48 Mirror contact part 50···Oscillating motor (actuator)

Claims

1. A distance measuring device that measures a distance to an object by scanning light externally and detecting light reflected by the object, A swing shaft (13) driven by an actuator (50); A mirror (18) that is driven to swing by the actuator and scans light to the outside; a holder (21-28) having a shaft holding portion (31) in which a hole portion (311) into which the oscillating shaft is press-fitted is formed, and a mirror holding portion (32, 33) formed integrally with the shaft holding portion and to which the mirror is attached by an adhesive member (29); Equipped with The distance measuring device has a mirror contact portion (41 to 48) formed on the mirror holding portion, the mirror contact portion protruding toward the mirror and contacting the mirror.

2. The shaft holding portion and the mirror holding portion are divided into regions by the mirror abutment portions (41, 44, 45), 2. The distance measuring device according to claim 1, wherein the mirror is attached to the holder by the adhesive member provided on the mirror holding portion, and is spaced apart from the shaft holding portion.

3. 3. The distance measuring device according to claim 1, wherein the length of the mirror holding portion in the direction of the swing axis is greater than that of the shaft holding portion.

Images