Lens holding mechanism, optical device, control system, and moving device

Abstract

To provide a lens holding mechanism capable of pressing a peripheral part of a lens in an optical axis direction while preventing the occurrence of torsion in an elastic member.SOLUTION: Disclosed is a lens holding mechanism for holding a lens, which includes: a lens barrel which houses the lens; a pressing ring which is movable in a direction along an optical axis with respect to the lens barrel; a rotary ring which rotates around the optical axis to move the pressing ring in the direction along the optical axis; and an elastic member which is arranged between the lens and the pressing ring. A rotation regulating part for regulating the rotation of the pressing ring around the optical axis is provided in the lens barrel, and the lens is pressed in the direction along the optical axis by energizing the elastic member to the peripheral part of the lens in the direction along the optical axis by the movement of the pressing ring.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a lens holding mechanism, an optical device, a control system, and a mobile device.

Background Art

[0002] In recent years, as an in-vehicle sensor used for autonomous driving and the like, such as a lidar device that uses laser light to measure the inter-vehicle distance, that is, so-called LIDAR (Laser Imaging And Ranging), the mounting of optical devices on automobiles has been increasing.

[0003] Generally, optical devices used as in-vehicle sensors are exposed to severe environmental changes. On the other hand, as a means for alleviating changes in the position of each lens with respect to environmental changes in the optical device, particularly changes in the ambient temperature, a structure in which an elastic member is disposed between a lens and a retaining ring, as described in Patent Document 1, for example, is known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, a structure is adopted in which an elastic member is disposed between a lens and a retaining ring. In the configuration of this Patent Document 1, due to the contact resistance between the retaining ring and the elastic member, the elastic member may be twisted. When the elastic member is twisted, problems such as the biasing force applied to the lens becoming non-uniform and the elastic member protruding into the effective light beam occur.

[0006] Furthermore, even when using the method of inserting friction damping sheets before and after the elastic member, as described in Patent Document 1, twisting of the elastic member occurs depending on the tightening force of the retaining ring, making it difficult to control the amount of twisting of the elastic member.

[0007] Therefore, the present invention aims to provide a lens holding mechanism that can hold the peripheral portion of the lens in the optical axis direction while preventing twisting in the elastic member. [Means for solving the problem]

[0008] To achieve the above objective, a lens holding mechanism as one aspect of the present invention is a lens holding mechanism for holding a lens, comprising: a lens barrel housing the lens; a retaining ring movable in a direction along the optical axis relative to the lens barrel; a rotating ring that rotates around the optical axis to move the retaining ring in a direction along the optical axis; and an elastic member disposed between the lens and the retaining ring, wherein the lens barrel is provided with a rotation restricting part that restricts the rotation of the retaining ring around the optical axis and a movement restricting part that restricts the movement of the retaining ring in a direction along the optical axis. The retaining ring and the rotating ring are screwed together. The device is characterized in that the movement of the retaining ring biases the elastic member relative to the peripheral portion of the lens in a direction along the optical axis, thereby pressing the lens in a direction along the optical axis. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a lens holding mechanism that can hold the peripheral portion of the lens in the optical axis direction while preventing twisting in the elastic member. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram illustrating an example of the structure of the optical device according to Example 1. [Figure 2] This is a cross-sectional view illustrating the structure of the telescope according to Example 1. [Figure 3]This is a cross-sectional view of the area around the image sensor of the lens unit according to Example 2. [Figure 4] This is a diagram showing the configuration of the in-vehicle system according to Example 3. [Figure 5] This is a schematic diagram of a vehicle as a mobile device including the in-vehicle system according to Example 3. [Figure 6] This flowchart shows an example of the operation of the in-vehicle system according to Example 3. [Modes for carrying out the invention]

[0011] Preferred embodiments of the present invention will be described below with reference to the attached drawings, using examples and figures. In each figure, the same reference numeral is used for the same member or element, and redundant explanations are omitted or simplified.

[0012] <Example 1> Figure 1 is a diagram illustrating the structure of the optical device (optical instrument) 100 according to Example 1. As shown in Figure 1, the optical device 100 of Example 1 is a so-called coaxial LIDAR in which the optical axes of the illumination system that illuminates the object and the receiving system that receives reflected and scattered light from the object are aligned by a perforated mirror 4.

[0013] The optical device 100 according to Example 1 includes a perforated mirror 4, a fixed mirror 5, a movable mirror 6, a condensing lens 7, a light-receiving element 8, a base lens barrel 9, a light source forming unit (light-emitting unit) 10, a control unit 14, and a telescope 20.

[0014] The perforated mirror (light guide) 4 is fixedly held to the base lens barrel 9 and is a mirror having a hole 4a (opening). The perforated mirror 4 can transmit laser light 12 through the hole 4a and reflect it through the reflective surface 4b. The perforated mirror 4 guides the laser light 12 from the light source forming unit 10 to the fixed mirror 5 and guides the reflected light from the fixed mirror 5 to the focusing lens 7. The fixed mirror 5 is a mirror fixedly held to the base lens barrel 9. The fixed mirror 5 guides the laser light 12 from the perforated mirror 4 to the movable mirror 6 and guides the reflected light from the movable mirror 6 to the perforated mirror 4.

[0015] The movable mirror (deflection unit, scanning unit) 6 is fixed and held by the base lens barrel 9 and is a mirror that scans an object using illumination light from a light source. The movable mirror 6 is configured as a two-axis drive mirror that rotates around the Y-axis and the X-axis, which is a direction orthogonal to the Y-axis, in FIG. 1. Examples of the movable mirror 6 include a MEMS (Micro Electro Mechanical System) mirror. The movable mirror 6 irradiates the laser beam 12 from the fixed mirror 5 to the target area through the lens (optical element) of the telescope 20, and guides the reflected light 13 from the obstacle 11 in the target area to the fixed mirror 5 through the lens of the telescope 20.

[0016] The condenser lens 7 is fixed and held by the base lens barrel 9 and is an optical element (condensing optical system) that condenses the laser beam 12 from the perforated mirror 4 and guides the condensed laser beam 12 to the light receiving element 8. The light receiving element 8 is an element for photoelectrically converting the illumination light from the light source forming unit 10 and outputting a signal. As the light receiving element 8, a PD (Photo Diode), APD (Avalanche Photo Diode), SPAD (Singel PHTON Avalanche Diode), etc. are used. The perforated mirror 4, the fixed mirror 5, the movable mirror 6, the condenser lens 7, the light receiving element 8, etc. are incorporated into the base lens barrel 9 and are housed inside the base lens barrel 9.

[0017] The light source forming unit (light projecting unit) 10 includes a light source (semiconductor laser) 1, a converging lens 2, and a fixed aperture 3. The light source 1 is a light source that irradiates a laser beam (irradiation light) 12. The converging lens 2 is an optical element that adjusts the beam shape of the laser beam 12 from the light source 1 in the target irradiation area. The fixed aperture 3 is configured to block unnecessary light included in the laser beam 12 irradiated from the light source 1 through the converging lens 2 and is projected from the aperture 3a.

[0018] The control unit 14 includes a CPU, a memory (storage unit), etc., is composed of at least one computer, and is connected to each component of the optical device 100 via a line. Further, the control unit 14 comprehensively controls the operation adjustment of each component of the entire optical device 100 according to a computer program stored in the memory. Thereby, the operation of the flowchart of FIG. 6 described later is controlled. For example, the control unit 14 is preferably configured integrally with other parts of the optical device 100, but may be configured separately from other parts of the optical device 100.

[0019] In the first embodiment, the control unit 14 controls the light source 1, the movable mirror 6, the light receiving element 8, etc. Specifically, the control unit 14 drives the light source 1 and the movable mirror 6 at predetermined drive voltages and drive frequencies, respectively, and measures the light reception waveform at a specific frequency when receiving light by the light receiving element 8. Then, the control unit 14 measures the difference between the light reception time obtained by the light receiving element 8 and the light emission time of the light source 1, or the difference between the phase of the light reception signal obtained by the light receiving element 8 and the phase of the output signal of the light source 1, and multiplies the difference by the speed of light to determine the distance to the object.

[0020] The telescope (lens holding mechanism) 20 is an optical system that enlarges the diameter of the laser beam 12 from the movable mirror 6 and reduces the diameter of the reflected light 13 from the obstacle 11 (object). Specifically, it is composed of a plurality of optical elements (lenses) having refractive power, and is an optical system (afocal system) that has no refractive power in the entire system. The configuration of the telescope 20 will be described later.

[0021] Here, the laser beam 12 emitted from the light source forming unit 10 of the optical device 100 in the first embodiment is projected into the base barrel 9 from the opening 3a of the fixed aperture 3. The laser beam 12 projected from the opening 3a of the fixed aperture 3 passes through the hole 4a of the perforated mirror 4, is reflected by the fixed mirror 5, and is irradiated to the target area by the movable mirror 6.

[0022] The laser beam 12 emitted from the telescope 20 onto the target area is reflected by an obstacle 11 in the target area, passes through the telescope 20 as reflected light 13, and returns to the movable mirror 6. The reflected light 13 reflected by the movable mirror 6 is then reflected by the fixed mirror 5. Subsequently, the reflected light 13 is reflected by the reflective surface 4b of the perforated mirror 4 and guided to the focusing lens 7. The reflected light 13 that exits the focusing lens 7 is guided to the light-receiving element 8. The light-receiving element 8 converts the reflected light 13 into photoelectric energy and outputs a signal.

[0023] Figure 2 is an example of a cross-sectional view illustrating the configuration of the telescope 20 according to Embodiment 1. The configuration of the telescope 20 will be described below with reference to Figure 2. The telescope 20 of Embodiment 1 includes a lens 21, a lens 22, a spacer 23, a fixed lens barrel (moving lens barrel) 24, a retaining ring 25, a rotating ring 26, and an elastic member 27.

[0024] The outer diameters of lens 21 and spacer 23 are formed to be smaller than the inner diameter 24a of the fixed lens barrel 24. Specifically, the outer diameters of lens 21 and spacer 23 are formed to be about 10 to 20 μm smaller than the inner diameter 24a of the fixed lens barrel 24. In addition, the outer diameter of lens 22 is formed to be smaller than the inner diameter 24b of the fixed lens barrel 24. Specifically, the outer diameter of lens 22 is formed to be about 10 to 20 μm smaller than the inner diameter 24b of the fixed lens barrel 24. As a result, lens 21, lens 22, and spacer 23 can each be housed within the fixed lens barrel 24 in the direction of the optical axis (along the optical axis).

[0025] The spacer 23 has corners 23a and 23b that make line contact with the R2 surface of lens 21 and the R1 surface of lens 22, and regulates the eccentricity of lens 21 and lens 22 in the direction perpendicular to the optical axis (radial direction) and the distance in the direction of the optical axis.

[0026] The optical axis position of the retaining ring 25 relative to the fixed lens barrel 24 is determined by the contact between the annular end face 25d provided on the inner diameter of the retaining ring 25 and the annular projection (movement restricting portion) 24d provided on the fixed lens barrel 24. The projection 24d is formed to protrude by a predetermined amount on the outer circumference in the direction perpendicular to the optical axis. Furthermore, the position of the retaining ring 25 in the direction perpendicular to the optical axis is determined by the fitting of the inner diameter fitting portion 25e of the retaining ring 25 and the outer diameter fitting portion 24e of the fixed lens barrel 24.

[0027] The elastic member 27 is made of a material such as rubber and is integrally formed in an annular shape (ring shape). Because the elastic member 27 is formed in an integral annular shape, it makes contact with the entire circumference when it comes into contact with the peripheral part of the lens 21. While it is preferable that the elastic member 27 is integrally formed in an annular shape as described above, for example, the elastic member 27 may be configured in an annular shape that only a part of the lens 21 comes into contact with. Furthermore, it may be composed of, for example, three separate elastic members that come into contact with the lens 21 at predetermined intervals such as 120-degree intervals.

[0028] The elastic member 27 is positioned between the lens 21 and the retaining ring 25. Specifically, the elastic member 27 is held in place by the retaining ring 25 by being fitted into an annular groove 25a formed on the retaining ring 25. The groove 25a guides the elastic member 27 by sandwiching it, for example, when assembling the optical device 100 or the telescope 20, so that the position of the elastic member 27 does not shift (move) or come off. The groove 25a may be a recess (including concave shape and shapes equivalent to concave shape) or a semicircular shape, and any shape is acceptable as long as the position of the elastic member 27 does not shift when it is positioned. In addition, the groove 25a may also be provided on the R1 surface side of the lens 21, in which case the groove may not be provided on the retaining ring 25.

[0029] Next, the keyway 25b provided in the inner diameter of the retaining ring 25 is fitted with the key portion (rotation restricting portion) 24c of the fixed lens barrel 24. This restricts the rotation of the retaining ring 25 around the optical axis (circumferential direction). At this time, the male threaded portion 25c provided in the outer diameter (outer circumference side in the direction perpendicular to the optical axis) of the retaining ring 25 is screwed into the female threaded portion 26a provided in the inner diameter (inner circumference side in the direction perpendicular to the optical axis) of the rotating ring 26. This results in the retaining ring 25 and the rotating ring 26 being fitted and fixed together. In this state, when the rotating ring 26 is rotated around the optical axis, the retaining ring 25 can be moved only in the direction of the optical axis.

[0030] When manufacturing the configuration of Embodiment 1, the retaining ring 25 and the fixed lens barrel 24 are fitted together, and when the retaining ring 25 and the rotating ring 26 are fitted together, a predetermined gap is formed between the projection 24d of the rotating ring 26 and the end face 25d of the fixed lens barrel 24. The predetermined gap is formed with a predetermined width dimension (spacing B) in the optical axis direction. Furthermore, this width dimension of spacing B is the dimension when the elastic member 27 is in contact with the R1 surface of the lens 21 and the elastic member 27 is not biased against the lens 21. The gap with this width dimension in the optical axis direction, spacing B, is formed such that the following relationship (1) is given with respect to the cross-sectional dimension ΦA of the elastic member 27. (Math 1) ΦA>B (1) As shown in equation (1) above, the spacing B is a width dimension smaller than the cross-sectional dimension ΦA of the elastic member 27 described above. Therefore, the amount of deformation of the elastic member 27 in the optical axis direction is determined by the spacing B, which is the width dimension in the optical axis direction.

[0031] When the rotating ring 26 is rotated around the optical axis, the retaining ring 25 moves in the optical axis direction, biasing the R1 surface of the lens 21 in the optical axis direction with the elastic member 27 in between. The annular stopper 26b provided on the inner diameter of the rotating ring 26 comes into contact with the projection 24d of the fixed lens barrel 24 in the optical axis direction due to the biasing force of the elastic member 27. In addition, when the end face 25d of the retaining ring 25 is moved until it contacts the projection 24d of the fixed lens barrel 24, the elastic member 27 deforms by a distance B, and can bias the lens 21, lens 22, and spacer 23 against the receiving surface 24f of the fixed lens barrel 24.

[0032] Since the spacing B is smaller than the cross-sectional dimension ΦA of the elastic member 27, even if the rotating ring 26 is rotated around the optical axis and the end face 25d of the retaining ring 25 is brought into contact with the projection 24d, the deformation of the elastic member 27 in the optical axis direction can be kept almost constant. Furthermore, the retaining ring 25 is movable only in the optical axis direction. Therefore, when the retaining ring 25 is moved in the optical axis direction and the elastic member 27 is biased against the lens 21, the elastic member 27 does not twist due to rotational force, and it can contact the peripheral part of the lens 21 all around, thereby evenly pressing the lens 21.

[0033] In Example 1, for example, the fixed lens barrel 24, retaining ring 25, rotating ring 26, and spacer 23 are made of an aluminum alloy with a coefficient of thermal expansion of 26 × 10⁻⁶ / °C. In addition, the lenses 21 and 22 are made of glass material with a coefficient of thermal expansion of 7 × 10⁻⁶ / °C.

[0034] Here, as an example, let's assume that the thickness of the aluminum alloy spacer 23 is 5 mm, and the distance from the R1 surface receiving portion of the glass lens 21 to the R2 surface receiving portion of the lens 22 is 15 mm. The R1 surface receiving portion of lens 21 is the part of lens 21 that contacts the elastic member 27, and the R2 surface receiving portion of lens 22 is the part of lens 22 that contacts the receiving surface 24f of the fixed lens barrel 24.

[0035] At this time, a 1°C change in temperature causes a thermal expansion difference of approximately 0.19 μm between the R1 surface receiving portion of lens 21 and the R2 surface receiving portion of lens 22. In other words, a 1°C change in temperature causes a gap of approximately 0.19 μm between the fixed lens barrel 24 and the lenses. For example, if the optical device 100 is placed in an external environment such as outdoors, and the ambient temperature or the temperature inside the device rises by 60°C compared to when the optical device 100 was assembled, a play (amount of play) of approximately 11.4 μm occurs in the optical axis direction. Also, in an environment where the ambient temperature drops by 60°C compared to when the device was assembled, as described above, lens deformation of approximately 11.4 μm occurs in the optical axis direction.

[0036] The optical device 100 in Example 1 is intended for use in LIDAR, a laser irradiation device that uses laser light to measure the distance between vehicles, and is used in applications such as autonomous driving. Therefore, it is often exposed to harsh environmental changes. Consequently, if large temperature changes occur as described above, causing looseness in the optical axis direction, for example, lenses 21 and 22 may shift in a direction perpendicular to the optical axis (i.e., become eccentric). Alternatively, lenses 21 and 22 may deform, worsening aberrations. These can lead to shifts in the projection position and imaging position, potentially reducing the measurement accuracy of the obstacle 11. Furthermore, it may become difficult to measure minute feature points on the surface of the obstacle 11.

[0037] In Example 1, the play in the optical axis direction described above is absorbed by the elastic deformation of an elastic member 27 located in the groove 25a of the retaining ring 25, which contacts the lens 21 and biases the lens in the optical axis direction. That is, in an environment where the ambient temperature rises or falls by 60°C from the time of assembly of the optical device 100, the length of the lens in the optical axis direction changes by approximately 11.4 μm, but the amount of deformation of the lens in this case can be absorbed by the elastic member 27. Furthermore, in response to the play that occurs in the direction perpendicular to the optical axis (radial direction) of the lens 21 and lens 22, when exposed to the above-described environment, the projection 24d of the fixed lens barrel 24 is in contact with the end face 25d of the retaining ring 25. As a result, the relative eccentricity can be mitigated because the lens 21 and lens 22 are pressed against each other by the spacer 23 and the elastic member 27.

[0038] As described above, in the optical device 100 of Example 1, the play in the optical axis direction of lenses 21 and 22 incorporated into the telescope 20 can be absorbed by the elastic member 27. That is, by pressing down on multiple lenses (lenses 21, 22) and spacers 23 with a single annularly formed elastic member 27, the amount of play in multiple lenses and spacers caused by differences in linear expansion due to temperature changes can be absorbed by the elastic member 27. Furthermore, since the pressing ring 25 is movable only in the optical axis direction, the peripheral parts of the lenses can be pressed evenly without causing twisting due to rotational force in the elastic member 27. In addition, since the dimension of the predetermined gap B is smaller than the cross-sectional dimension ΦA of the elastic member 27, the elastic member 27 deforms by at most the dimension of gap B. As a result, the deformation of the elastic member 27 in the optical axis direction can be kept almost constant, and the peripheral parts of the lenses 21 can be pressed evenly.

[0039] In Example 1, a structure in which the telescope 20 is composed of two lenses is described, but the number of lenses is not limited to this; any number of lenses, one or more, is acceptable. Also, in Example 1, it is assumed that the structure will be applied to the telescope of a LIDAR, which is a laser irradiation device (laser radar device), but it is not limited to this and may be applied to other devices other than laser irradiation devices.

[0040] <Example 2> Example 1 describes an example in which an elastic member 27 is used in the fixing part of the front element (lens 21) of the LIDAR telescope. Example 2 describes a lens holding configuration by a sensor holder 35 that holds the image sensor 30 of the imaging lens unit. Matters not mentioned in Example 2 follow those of Example 1.

[0041] Figure 3 is a diagram illustrating the structure of the optical device 100 according to Embodiment 2. Specifically, it is a cross-sectional view of the area around the image sensor 30 of the imaging lens unit (lens holding mechanism) in the optical device 100.

[0042] In Figure 3, lenses 31, 32, and spacer 33 are incorporated into the fixed lens barrel 34 and constitute part of the imaging lens unit. The outer diameter of lens 31 is smaller than the inner diameter 34a of the fixed lens barrel 34. Specifically, the outer diameter of lens 31 is approximately 10 to 20 μm smaller than the inner diameter 34a of the fixed lens barrel 34. Similarly, the outer diameters of lens 32 and spacer 33 are smaller than the inner diameter 34b of the fixed lens barrel 34. Specifically, the outer diameters of lens 32 and spacer 33 are approximately 10 to 20 μm smaller than the inner diameter 34b of the fixed lens barrel 34. This allows lens 31, lens 32, and spacer 33 to be housed within the fixed lens barrel 34 along the optical axis.

[0043] The spacer 33 has corners 33a and 33b that make line contact with the R2 surface of lens 31 and the R1 surface of lens 32, and regulates the eccentricity of lens 31 and lens 32 in the direction perpendicular to the optical axis, and the distance in the direction of the optical axis.

[0044] The image sensor 30 is fixedly held in the sensor holder 35, and its position in the optical axis direction relative to the fixed lens barrel 34 is determined by the contact between an annular end face 35d provided on the sensor holder 35 and an annular projection (movement restricting portion) 34d provided on the inner diameter of the fixed lens barrel 34. The projection 34d is formed to protrude by a predetermined amount on the outer circumference in the direction perpendicular to the optical axis. Furthermore, the position of the sensor holder 35 in the direction perpendicular to the optical axis is determined by the fitting of the inner diameter fitting portion 35e of the sensor holder 35 and the outer diameter fitting portion 34e of the fixed lens barrel 34.

[0045] The elastic member 37 is positioned between the lens 32 and the sensor holder 35. Specifically, the elastic member 37 is held in place by the sensor holder 35 by being fitted into an annular groove 35a formed in the sensor holder 35. The groove 35a guides the elastic member 37 by sandwiching it, for example, when assembling the optical device 100 or the imaging lens unit, so that the installation position of the elastic member 27 does not shift (move) or come loose.

[0046] Furthermore, the keyway 35b provided in the inner diameter of the sensor holder 35 is fitted with the key portion (rotation restricting portion) 34c of the fixed lens barrel 34. This restricts the rotation of the sensor holder 35 around the optical axis. At this time, the male threaded portion 35c provided in the outer diameter of the sensor holder 35 is screwed into the female threaded portion 36a provided in the inner diameter of the rotating ring 36. This causes the sensor holder 35 and the rotating ring 36 to be fitted and fixed together. In this state, when the rotating ring 36 is rotated around the optical axis, the sensor holder 35 can be moved only in the direction of the optical axis.

[0047] Furthermore, when manufacturing the configuration of Embodiment 2, when the sensor holder 35 and the fixed lens barrel 34 are fitted together, and the sensor holder 35 and the rotating ring 36 are fitted together, a predetermined gap is formed between the projection 34d of the fixed lens barrel 34 and the end face 35d of the sensor holder 35. The predetermined gap is formed with a predetermined width dimension (spacing D) in the optical axis direction. The width dimension of this spacing D is the dimension when the elastic member 37 is in contact with the R2 surface of the lens 32 and the elastic member 37 is not biased against the lens 32. The gap with a width dimension of spacing D in the optical axis direction is formed such that the following relationship (2) is given with respect to the cross-sectional dimension ΦC of the elastic member 37. (Math 2) ΦC>D (2) As shown in equation (2) above, the spacing D is a width dimension smaller than the cross-sectional dimension ΦC of the elastic member 37 described above. Therefore, the amount of deformation of the elastic member 37 in the optical axis direction is determined by the spacing D, which is the width dimension in the optical axis direction.

[0048] When the rotating ring 36 is rotated around the optical axis, the sensor holder 35 moves in the optical axis direction, biasing the R2 surface of the lens 32 in the optical axis direction with the elastic member 27 in between. The annular stopper 36b provided on the inner diameter of the rotating ring 36 comes into contact with the projection 34d provided on the fixed lens barrel 34 in the optical axis direction due to the biasing force of the elastic member 37. In addition, when the end face 35d of the sensor holder 35 is moved until it contacts the projection 34d of the fixed lens barrel 34, the elastic member 37 deforms by a distance D, and can bias the lens 32, lens 31, and spacer 33 against the receiving surface 35f of the sensor holder 35.

[0049] Since the spacing D is smaller than the cross-sectional dimension ΦC of the elastic member 37, even if the rotating ring 36 is rotated around the optical axis and the end face 35d of the sensor holder 35 is brought into contact with the projection 34d, the deformation of the elastic member 37 in the optical axis direction can be kept almost constant. Furthermore, the sensor holder 35 is movable only in the optical axis direction. Therefore, when the sensor holder 35 is moved in the optical axis direction and the elastic member 37 is biased against the lens 32, the elastic member 37 does not twist due to rotational force, and it can contact the entire periphery of the lens 32, pressing the lens 32 evenly.

[0050] In Example 2, for example, the fixed lens barrel 34, sensor holder 35, rotating ring 36, and spacer 33 are made of an aluminum alloy with a coefficient of thermal expansion of 26 × 10⁻⁶ / °C. In addition, the lenses 31 and 32 are made of glass material with a coefficient of thermal expansion of 7 × 10⁻⁶ / °C.

[0051] Here, as an example, let's assume that the thickness of the aluminum alloy spacer 33 is 5 mm, and the distance between the R1 surface receiving portion of the glass lens 31 and the R2 surface receiving portion of the lens 32 is 15 mm. The R1 surface receiving portion of lens 31 is the part of lens 31 that contacts the receiving surface 35f of the sensor holder 35, and the R2 surface receiving portion of lens 32 is the part of lens 32 that contacts the elastic member 37.

[0052] At this time, a 1°C change in temperature generates a thermal expansion difference of approximately 0.19 μm between the R1 surface receiving portion of lens 31 and the R2 surface receiving portion of lens 32. That is, a gap of approximately 0.19 μm occurs between the fixed lens barrel 34 and the lenses. For example, if the optical device 100 is placed in an external environment such as outdoors, and the ambient temperature or the temperature inside the device rises by 60°C compared to when the optical device 100 was assembled, a play (amount of play) of approximately 11.4 μm occurs in the optical axis direction. Also, in an environment where the ambient temperature drops by 60°C compared to when it was assembled, as described above, lens deformation of approximately 11.4 μm occurs in the optical axis direction. The optical device 100 in Example 2, like in Example 1, is intended to be applied to a LIDAR, which is a laser irradiation device that uses laser light to measure the distance between vehicles and is used in autonomous driving, etc.

[0053] In Example 2, the play in the optical axis direction described above is absorbed by the elastic deformation of an elastic member 37 located in the groove 35a of the sensor holder 35, which contacts the lens 32 and biases the lens in the optical axis direction. That is, in an environment where the ambient temperature rises or falls by 60°C from the time of assembly of the optical device 100, the length of the lens changes by approximately 11.4 μm in the optical axis direction, but the amount of deformation of the lens in this case can be absorbed by the elastic member 37. Furthermore, in the environment described above, when exposed to play occurring in the direction perpendicular to the optical axis (radial direction) between lens 31 and lens 32, the projection 34d of the fixed lens barrel 34 is in contact with the end face 35d of the sensor holder. As a result, lens 31 and lens 32 are pressed against each other by the spacer 33 and the elastic member 27, thus mitigating relative eccentricity.

[0054] As described above, in the optical device 100 of Example 2, the play in the optical axis direction of lenses 31 and 32 incorporated into the imaging lens unit can be absorbed by the elastic member 27. That is, by pressing down on multiple lenses (lenses 31, 32) and spacers 33 with a single annularly formed elastic member 37, the amount of play in multiple lenses and spacers caused by differences in linear expansion due to temperature changes can be absorbed by the elastic member 37. Furthermore, since the sensor holder 35 is movable only in the optical axis direction, the elastic member 37 can be pressed evenly around the lens without causing twisting due to rotational force, similar to Example 1. Moreover, since the dimension of the predetermined gap D is smaller than the cross-sectional dimension ΦC of the elastic member 37, the elastic member 37 deforms by at most the dimension of the gap D. As a result, the deformation of the elastic member 37 in the optical axis direction can be kept almost constant, and the peripheral part of the lens can be pressed evenly.

[0055] Although Example 2 describes a structure in which the imaging lens unit is composed of two lenses, the number of lenses is not limited to this; any number of lenses, one or more, is acceptable.

[0056] <Example 3> Figure 4 is a configuration diagram of the optical device 100 and the in-vehicle system (driving assistance device) 1000 equipped therewith according to each of the above embodiments. The in-vehicle system 1000 is a control system that is held by a movable mobile body (mobile device) such as an automobile (vehicle) and assists the driving (operation) of the vehicle 500 based on distance information of objects such as obstacles and pedestrians around the vehicle acquired by the optical device 100. Figure 5 is a schematic diagram of the vehicle 500 as a mobile device including the in-vehicle system 1000. In Figure 5, the case in which the distance measurement range (detection range) of the optical device 100 is set to the front of the vehicle 500 is shown, but the distance measurement range may also be set to the rear or side of the vehicle 500.

[0057] As shown in Figure 4, the in-vehicle system 1000 includes an optical device 100, a vehicle information acquisition device 200, a control device (control unit, ECU: electronic control unit) 300, and a warning device (warning unit) 400. In the in-vehicle system 1000, the control unit 14 of the optical device 100 has the functions of a distance acquisition unit (acquisition unit) and a collision determination unit (determination unit). However, if necessary, the in-vehicle system 1000 may have a distance acquisition unit and a collision determination unit separate from the control unit 14, and each may be located outside the optical device 100 (for example, inside the vehicle 500). Alternatively, the control device 300 may be used as the control unit 14.

[0058] Figure 6 is a flowchart showing an example of the operation of the in-vehicle system 1000 according to Example 3. The operation of the in-vehicle system 1000 will be described below in accordance with this flowchart.

[0059] First, in step S1, the light source forming unit 10 of the optical device 100 illuminates the object (obstacle 11) around the vehicle 500 with laser light 12 and receives reflected light 13 from the object. The control unit 14 receives the reflected light 13 and acquires distance information of the object based on the signal output by the light receiving element (light receiving unit) 8. At this time, the distance acquisition unit functions as a distance information acquisition means that acquires distance information of an object based on the signal from the light receiving element 8. Here, the distance information can be any information relating to the distance from the moving device (vehicle 500) to the object, and does not have to be the distance itself. In step S2, the vehicle information acquisition device 200 acquires vehicle information including the vehicle speed, yaw rate, steering angle, etc. of the vehicle 500. Then, in step S3, the control unit 14 uses the distance information acquired in step S1 and the vehicle information acquired in step S2 to determine whether the distance to the object falls within a preset distance range.

[0060] This allows the system to determine whether or not an object exists within a set distance around the vehicle 500 and to determine the possibility of a collision between the vehicle 500 and the object. Steps S1 and S2 may be performed in the reverse order of the above, or they may be processed in parallel. The control unit 14 determines "possibility of collision" if an object exists within the set distance (step S4), and determines "no possibility of collision" if an object does not exist within the set distance (step S5).

[0061] Next, if the control unit 14 determines that there is a possibility of collision, it notifies (transmits) the determination result to the control device 300 and the warning device 400. At this time, the control device 300 controls the vehicle 500 based on the determination result from the control unit 14 (step S6), and the warning device 400 issues a warning to the user (driver, passengers) of the vehicle 500 based on the determination result from the control unit 14 (step S7). At this time, the warning device 400 functions as a warning means that issues a warning according to the distance information of the object. Note that notification of the determination result only needs to be made to at least one of the control device 300 and the warning device 400.

[0062] The control device 300 functions as a control means that can control the driving and movement of the vehicle 500 by outputting control signals to the vehicle's drive unit (engine, motor, etc.). For example, the control device 300 can perform controls such as applying the brakes, releasing the accelerator, turning the steering wheel, and generating control signals to apply braking force to each wheel to suppress the output of the engine or motor. The warning device 400 also provides warnings to the user, such as emitting a warning sound, displaying warning information on a screen such as a car navigation system, or vibrating the seat belt or steering wheel.

[0063] As described above, the in-vehicle system 1000 according to Embodiment 3 enables the detection and measurement of objects through the above processing, making it possible to avoid collisions between the vehicle 500 and objects. In particular, by applying the optical device 100 according to each of the embodiments described above to the in-vehicle system 1000, high distance measurement accuracy can be achieved, making it possible to detect objects and determine collisions with high accuracy.

[0064] In Example 3, the in-vehicle system 1000 was applied to driver assistance (collision damage mitigation), but it is not limited to this, and the in-vehicle system 1000 may also be applied to cruise control (including with full-speed following function) or autonomous driving. Furthermore, the in-vehicle system 1000 is not limited to automobiles and other vehicles, but can be applied to mobile objects such as ships, aircraft, and industrial robots. Moreover, it is not limited to mobile objects, but can be applied to various devices that utilize object recognition, such as intelligent transportation systems (ITS) and surveillance systems.

[0065] Furthermore, the in-vehicle system 1000 and the vehicle 500 may be equipped with a notification device (notification unit) to notify the manufacturer of the in-vehicle system or the dealer of the mobile device in the event that the vehicle 500 collides with an obstacle. For example, the notification device may be one that sends information regarding the collision between the vehicle 500 and the obstacle (collision information) to a pre-set external notification destination via email or the like.

[0066] In this way, by adopting a configuration in which collision information is automatically notified by the notification device, it is possible to promptly take action such as inspection and repair after a collision occurs. The recipients of the collision information may be insurance companies, medical institutions, the police, or any other name set by the user. Furthermore, the notification device may be configured to notify recipients not only of collision information, but also of malfunction information of various parts and information on the wear and tear of consumables. The detection of whether or not a collision has occurred may be performed using distance information acquired based on the output from the light-receiving element 8 described above, or it may be performed by other detection units (sensors).

[0067] Although preferred embodiments of the present invention have been described above using examples, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its essence. Furthermore, the above embodiments may be implemented in combination.

[0068] Furthermore, some or all of the control in each of the above-described embodiments may be performed by supplying a computer program that realizes the functions of each of the above-described embodiments to the optical device 100, etc., via a network or various storage media. The computer (or CPU, MPU, etc.) in the optical device 100, etc., may then read and execute the program. In that case, the program and the storage medium storing the program constitute the present invention. [Explanation of symbols]

[0069] 1. Semiconductor laser 2. Converging lens 4 Perforated mirror 5 Fixed mirror 6. Movable Mirror 7. Focusing lens 8. Photodetector 9 Base tube 10 Light source forming section 14 Control Unit 20 Telescope 21, 22 lenses 23 Spacers 24 Fixed Telescope Tube 25 Presser Ring 26 Rotating Rings 27 Elastic members

Claims

1. A lens holding mechanism for holding a lens, A lens barrel housing the aforementioned lens, A retaining ring that is movable in a direction along the optical axis relative to the lens barrel, A rotating ring that rotates around the optical axis to move the retaining ring in a direction along the optical axis, It has an elastic member disposed between the lens and the retaining ring, The lens barrel is provided with a rotation restricting part that restricts the rotation of the retaining ring around the optical axis, and a movement restricting part that restricts the movement of the retaining ring in the direction along the optical axis. The retaining ring and the rotating ring are screwed together. A lens holding mechanism characterized in that the movement of the retaining ring biases the elastic member relative to the peripheral portion of the lens in a direction along the optical axis, thereby pressing the lens in a direction along the optical axis.

2. The lens holding mechanism according to claim 1, characterized in that the elastic member is held by the retaining ring by being fitted into a recess formed in the retaining ring.

3. A scanning unit that scans an object using illumination light from a light source, The lens holding mechanism is as described in claim 1 or 2, and comprises An optical device characterized by guiding the reflected light from the object illuminated by the scanning unit to a light-receiving element via the lens.

4. The optical device is provided as described in claim 3, A control system characterized by having a distance acquisition unit that acquires distance information of an object based on a signal from the light-receiving element.

5. The control system according to claim 4, further comprising a control device that controls the driving of a moving device based on the distance information.

6. The control system according to claim 4 or 5, further comprising a warning device that issues a warning in accordance with the distance information of the object.

7. The optical device is provided as described in claim 3, A mobile device characterized by being able to hold and move the optical device.

8. The moving device according to claim 7, further comprising control means for controlling the driving of the moving device based on distance information of the object.

9. The mobile device according to claim 7, further comprising warning means that gives a warning according to distance information of the object.

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