Lens unit, camera module, in-vehicle system and vehicle

Abstract

To provide a lens unit which reduces pressure acting on a lens and can suppress deformation of the lens, a camera module, an on-vehicle system, and a vehicle.SOLUTION: In a lens unit 11, a lens barrel 12 is formed of a resin. Lenses 14, 15, 17 and 18 constituting a lens group L stored in the lens barrel 12 are made of glass, are assembled in the lens barrel 12 by press fitting, and its radial outer peripheral ends 14a, 15a, 17a and 18a in a cross section in the direction of an optical axis O are brought into point contact with the inner surface 12d of the lens barrel 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention particularly relates to a lens unit constituting an on-board camera mounted on a vehicle such as an automobile, a camera module, an on-board system, and a vehicle equipped with the on-board system. [Background technology]

[0002] In recent years, automobiles have been equipped with on-board cameras to assist with parking and prevent collisions through image recognition, and attempts have also been made to apply this to autonomous driving. Camera modules such as these on-board cameras generally include a lens unit having a lens group consisting of multiple lenses arranged along an optical axis, a lens barrel that houses and holds this lens group, and an aperture member arranged between at least one of the lenses in the lens group (see, for example, Patent Document 1).

[0003] In lens units, there have traditionally been various ways of assembling lenses into a lens barrel. For example, depending on the materials of the lens barrel and the lens, the lens may be assembled into the lens barrel via a spacer or the like, or the lens may be lightly press-fit directly into the inner surface of the lens barrel with a predetermined diameter difference, taking advantage of the inner surface shape of the lens barrel, or the lens may be assembled into the lens barrel such that the outer periphery of the lens and the inner periphery of the lens barrel are in point contact in a cross section perpendicular to the optical axis direction. In particular, in the case of assembling the lens and lens barrel in point contact, there is also an assembly method in which a lens with a circular cross section is press-fit into a lens barrel whose inner surface is polygonal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-231993 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, including the aforementioned case in which a lens is press-fitted into a lens barrel to be assembled with the outer periphery of the lens making point contact with the inner periphery of the lens barrel in a cross section perpendicular to the optical axis direction, generally, when a lens is assembled into a lens barrel, the outer periphery of the lens makes line contact with the inner periphery of the lens barrel in a cross section along the optical axis direction, as shown in Fig. 13. That is, in the example of Fig. 13, lenses 102 and 103 are assembled into lens barrel 100 via spacer 110, and each lens 102 and 103 has linear portions 102b and 103b on the side end faces (edges) of its annular outer peripheral flanges 102a and 103a that fit in line contact (linear contact with a certain length) with inner surface 100a of lens barrel 100, which extends linearly along the optical axis O in a cross section along the optical axis O.

[0006] However, when lenses 102, 103 are press-fitted into lens barrel 100 in this assembled state, radially inward compressive stress constantly acts on lenses 102, 103. Therefore, particularly in the above-described configuration in which the lenses are press-fitted into the lens barrel with point contact between the outer periphery of the lens and the inner periphery of the lens barrel in a cross section perpendicular to the optical axis direction, if the lens barrel is formed of resin and the lenses are made of glass, large pressure acts on edges (straight portions) 102b, 103b, which are the press-fit surfaces, causing deformation of lenses 102, 103 and potentially preventing desired optical performance. In today's world where glass is becoming thinner and high assembly precision and high optical performance are required, even slight deformation of lenses has a significant impact on optical performance, and therefore preventing lens deformation due to such compressive stress (large pressure) is an urgent issue in this technical field.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a lens unit, a camera module, an in-vehicle system, and a vehicle that can reduce the pressure acting on the lens and suppress deformation of the lens. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a lens unit including: a cylindrical lens barrel that forms an internal storage space for storing and holding lenses; and a lens group that is incorporated into the internal storage space of the lens barrel and that is made up of a plurality of lenses arranged along an optical axis, the lens barrel is made of resin, At least one lens constituting the lens group is made of glass and is press-fit into the lens barrel, with its radially outer edge in point contact with the inner surface of the lens barrel in a cross section along the optical axis.

[0009] According to the above-described configuration of the present invention, the radially outer edge of the lens is in point contact with the inner surface of the lens barrel in a cross section along the optical axis, so that the pressure acting on the lens can be reduced and lens deformation can be suppressed in the unique press-fit configuration in which a glass lens is press-fitted into a resin lens barrel, thereby making it possible to obtain desired optical characteristics without degrading optical performance.

[0010] Here, "point contact" includes cases where there is a contact area within a certain range, and in this specification, it refers to a contact length between the lens and the lens barrel (length along the optical axis) being 1 / 3 or less of the edge thickness in a cross section along the optical axis.

[0011] In the above configuration, it is also preferable that the lens that makes point contact with the lens barrel has its radially outer edge forming an arc in a cross section along the optical axis, and that the apex of this arc makes point contact with the inner surface of the lens barrel. This makes it possible to achieve a nearly uniform stress distribution without stress concentration in the area of ​​action of the lens where compressive stress acts radially inward from the lens barrel, which can contribute to suppressing lens deformation.

[0012] In the above configuration, the lens that is in point contact with the lens barrel in a cross section along the optical axis direction may also have its radially outer edge in point contact with the inner surface of the lens barrel in a cross section perpendicular to the optical axis direction. This effectively reduces the pressure acting on the lens and reliably suppresses lens deformation in a fitting configuration in which a glass lens is press-fit into a resin lens barrel in point contact in a cross section perpendicular to the optical axis direction, i.e., in a specific press-fit fitting configuration in which lens deformation due to compressive stress is particularly likely to occur.

[0013] Here, "point contact" in a cross section perpendicular to the optical axis includes cases where there is a certain contact area, and in this specification, it refers to a contact length between the lens and the lens barrel that is one-third or less of the edge thickness in a cross section perpendicular to the optical axis. This type of point contact can be achieved, for example, by press-fitting a lens with a circular cross section into a lens barrel with a polygonal inner surface, but is not limited to this.

[0014] In the above configuration, the contact point of the lens that makes point contact with the lens barrel is preferably located at the radially outer edge of the lens closest to the radial centerline, which is the perpendicular bisector of the line segment along the optical axis that defines the lens thickness at the center of the lens, in a cross section along the optical axis. This means that if the radially outer edge of the lens is located on the radial centerline, the contact point will be located on the radial centerline. This can more effectively reduce the pressure acting on the lens from the lens barrel, further improving the effect of suppressing lens deformation.

[0015] Test data demonstrating such a high effect of suppressing lens deformation is shown in FIGS. 9A shows a conventional press-fit configuration of a lens into a lens barrel, i.e., a press-fit configuration in which the outer peripheral surface of lens A and the inner peripheral surface of lens barrel B are in line contact in a cross section along the optical axis O. Specifically, lens A is a meniscus lens that is convex toward the image side, and in the cross section shown along the optical axis O, lens A has a linear portion Aa on the side end face (edge) of its annular outer peripheral flange Ab that is in line contact with the inner surface Ba of lens barrel B, which extends linearly along the optical axis O. In this press-fit configuration, data on the amount of deformation at five measurement points P1, P2, P3, P4, and P5 on the surface Ac of lens A facing the object side (surface R1) is shown in a table in FIG. 9B and a graph in FIG. 9C. Measurement point P1 is a point on the optical axis O (lens center) (deformation amount -3.92E-03), measurement point P2 is a point on surface Ac 0.56 mm radially away from the optical axis O (deformation amount -3.03E-03), measurement point P3 is a point on surface Ac 1.37 mm radially away from the optical axis O (deformation amount -2.66E-03), measurement point P4 is a point on surface Ac 1.86 mm radially away from the optical axis O (deformation amount -2.01E-03), and measurement point P5 is a point on surface Ac 2.29 mm radially away from the optical axis O (deformation amount -1.37E-03). Data on the deformation amounts at five measurement points Q1, Q2, Q3, Q4, and Q5 on the back surface (surface R2) Ad facing the image side of lens A are shown in table (d) of FIG. 9 and as a graph (e) of FIG. Measurement point Q1 is a point on the optical axis O (center of the lens) (deformation amount -3.68E-03), measurement point Q2 is a point on the back surface Ad 0.56 mm radially away from the optical axis O (deformation amount -3.61E-03), measurement point Q3 is a point on the back surface Ad 1.37 mm radially away from the optical axis O (deformation amount -3.25E-03), measurement point Q4 is a point on the back surface Ad 1.86 mm radially away from the optical axis O (deformation amount -2.87E-03), and measurement point Q5 is a point on the back surface Ad 2.29 mm radially away from the optical axis O (deformation amount -2.41E-03). As can be seen from these data, on the front surface Ac, even the radially outermost measurement point P5 has an absolute value of 1.37E-03 (=1.37×10 -3) mm, and the absolute value of the deformation at measurement point P1 on the optical axis O, which is the innermost radial point, is 3.29E-03 mm. On the other hand, the deformation at the back surface Ad increases even more. Here, the minus sign indicates the direction of change.

[0016] In contrast, Figure 10(a) shows the press-fit configuration of the present invention for a lens in a lens barrel, i.e., a press-fit configuration in which, in a cross section along the optical axis O, the radially outer edge AA of lens A is in point contact with the inner surface Ba of lens barrel B, and the contact point AAa is located at the portion of the radially outer edge AA closest to the radial centerline L1, which is the perpendicular bisector of a line segment MN along the optical axis O that defines the lens thickness dimension D at the center of lens A. In particular, in this example, the contact point AAa is located on the radial centerline L1. In this press-fit configuration, data on the deformation amount at five measurement points P1, P2, P3, P4, and P5 on the surface Ac of lens A facing the object side (surface R1) are shown in a table in Figure 10(b) and a graph in Figure 10(c). Measurement point P1 is a point on the optical axis O (lens center) (deformation amount 4.96E-04), measurement point P2 is a point on surface Ac 0.83 mm radially away from the optical axis O (deformation amount 5.60E-04), measurement point P3 is a point on surface Ac 1.30 mm radially away from the optical axis O (deformation amount 6.42E-04), measurement point P4 is a point on surface Ac 2.04 mm radially away from the optical axis O (deformation amount 7.49E-04), and measurement point P5 is a point on surface Ac 2.35 mm radially away from the optical axis O (deformation amount 7.42E-04). Data on the deformation amounts at five measurement points Q1, Q2, Q3, Q4, and Q5 on the back surface (surface R2) Ad facing the image side of lens A are shown in table (d) of FIG. 10 and graph (e) of FIG. Measurement point Q1 is a point on the optical axis O (center of the lens) (deformation amount 2.45E-04), measurement point Q2 is a point on the back surface Ad 0.59 mm radially away from the optical axis O (deformation amount 2.59E-04), measurement point Q3 is a point on the back surface Ad 1.38 mm radially away from the optical axis O (deformation amount 3.24E-04), measurement point Q4 is a point on the back surface Ad 1.86 mm radially away from the optical axis O (deformation amount 3.87E-04), and measurement point Q5 is a point on the back surface Ad 2.29 mm radially away from the optical axis O (deformation amount 4.45E-04). As can be seen from these data, with this press-fit fitting configuration, the amount of deformation is significantly reduced overall compared to the conventional press-fit fitting configuration shown in FIG.

[0017] 11(a) shows the press-fit configuration of the present invention of the lens relative to the lens barrel, i.e., in a cross section along the optical axis O, the radially outer edge AA of lens A is in point contact with the inner surface Ba of lens barrel B, and this contact point AAa is located at the portion of radially outer edge AA that is farthest from the radial centerline L1. In this press-fit configuration, data on the amount of deformation at five measurement points P1, P2, P3, P4, and P5 on the surface Ac of lens A facing the object side (surface R1) is shown in a table in FIG. 11(b) and a graph in FIG. 11(c). Measurement point P1 is a point on the optical axis O (lens center) (deformation amount -2.24E-03), measurement point P2 is a point on surface Ac 0.59 mm radially away from the optical axis O (deformation amount -2.20E-03), measurement point P3 is a point on surface Ac 1.30 mm radially away from the optical axis O (deformation amount -2.01E-03), measurement point P4 is a point on surface Ac 1.70 mm radially away from the optical axis O (deformation amount -1.81E-03), and measurement point P5 is a point on surface Ac 2.20 mm radially away from the optical axis O (deformation amount -1.46E-03). Data on the deformation amounts at five measurement points Q1, Q2, Q3, Q4, and Q5 on the back surface (surface R2) Ad facing the image side of lens A are shown in table (d) of FIG. 11 and graph (e). Measurement point Q1 is a point on the optical axis O (center of the lens) (deformation amount -2.24E-03), measurement point Q2 is a point on the back surface Ad 0.59 mm radially away from the optical axis O (deformation amount -2.21E-03), measurement point Q3 is a point on the back surface Ad 1.12 mm radially away from the optical axis O (deformation amount -2.12E-03), measurement point Q4 is a point on the back surface Ad 1.63 mm radially away from the optical axis O (deformation amount -1.98E-03), and measurement point Q5 is a point on the back surface Ad 2.07 mm radially away from the optical axis O (deformation amount -1.80E-03). As can be seen from these data, with this press-fitting configuration, the amount of deformation is generally reduced compared to the conventional press-fitting configuration shown in FIG. 9, but the degree of reduction in the amount of deformation is smaller compared to the press-fitting configuration shown in FIG. 10.

[0018] 12(a) shows the press-fit configuration of the present invention of the lens relative to the lens barrel, i.e., a press-fit configuration in which, in a cross section along the optical axis O, the radially outer peripheral edge AA of lens A is in point contact with the inner surface Ba of lens barrel B, and the contact point AAa is located at a portion of the radially outer peripheral edge AA that is farther from the radial center line L1 than in the case of Fig. 10 and closer to the radial center line L1 than in Fig. 11. In this press-fit configuration, data on the deformation amount at five measurement points P1, P2, P3, P4, and P5 on the surface Ac of lens A facing the object side (surface R1) is shown in a table in Fig. 12(b) and a graph in Fig. 12(c). Measurement point P1 is a point on the optical axis O (lens center) (deformation amount -1.26E-03), measurement point P2 is a point on surface Ac 0.59 mm radially away from the optical axis O (deformation amount -1.21E-03), measurement point P3 is a point on surface Ac 1.07 mm radially away from the optical axis O (deformation amount -1.11E-03), measurement point P4 is a point on surface Ac 1.70 mm radially away from the optical axis O (deformation amount -8.75E-04), and measurement point P5 is a point on surface Ac 2.35 mm radially away from the optical axis O (deformation amount -5.51E-04). Data on the deformation amounts at five measurement points Q1, Q2, Q3, Q4, and Q5 on the back surface (surface R2) Ad facing the image side of lens A are shown in a table in FIG. 12(d) and a graph in FIG. 12(e). Measurement point Q1 is a point on the optical axis O (center of the lens) (deformation amount -1.38E-03), measurement point Q2 is a point on the back surface Ad 0.56 mm radially away from the optical axis O (deformation amount -1.36E-03), measurement point Q3 is a point on the back surface Ad 1.11 mm radially away from the optical axis O (deformation amount -1.28E-03), measurement point Q4 is a point on the back surface Ad 1.86 mm radially away from the optical axis O (deformation amount -1.08E-03), and measurement point Q5 is a point on the back surface Ad 2.29 mm radially away from the optical axis O (deformation amount -9.19E-04). As can be seen from these data, with this press-fit fitting configuration, the amount of deformation is generally reduced compared to the conventional press-fit fitting configuration shown in FIG. 9 and the press-fit fitting configuration shown in FIG. 11, but the degree of reduction in the amount of deformation is smaller compared to the press-fit fitting configuration shown in FIG. 10.

[0019] As can be seen by comparing Figures 10, 11 and 12, the farther the contact point AAa is from the radial center line L1, the smaller the degree of reduction in the amount of deformation compared to the conventional Figure 9 (in other words, the closer the contact point AAa is to the radial center line L1, the greater the degree of reduction in the amount of deformation).Therefore, it can be said that if the contact point AAa of lens A, which is in point contact with the lens barrel B, is positioned at the radial outer edge AA closest to the radial center line L1 in a cross section along the optical axis, the pressure acting on lens A from the lens barrel B can be more effectively reduced, thereby further enhancing the effect of suppressing lens deformation.

[0020] The present invention also provides a camera module having the lens unit described above, an in-vehicle system having the camera module, and a vehicle equipped with the in-vehicle system, which can achieve the same effects as the lens unit described above. [Effects of the Invention]

[0021] According to the present invention, the radially outer edge of the lens is in point contact with the inner surface of the lens barrel in a cross section along the optical axis direction, so that in the unique press-fit configuration in which a glass lens is press-fit into a resin lens barrel, the pressure acting on the lens can be reduced and deformation of the lens can be suppressed. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic cross-sectional view (cross-sectional view along the optical axis) of a lens unit according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the lens unit of FIG. 1 at the position of a second lens, the cross-sectional view being perpendicular to the optical axis direction. [Figure 3] 1A is an enlarged cross-sectional view (cross-sectional view along the optical axis) of the essential part showing the state in which another lens (a lens that makes point contact with the lens barrel) that can constitute the lens group of the lens unit of FIG. 1 is press-fitted into the lens barrel, and FIG. 1B is an enlarged view of the X part of FIG. [Figure 4](a) to (c) show lens press-fit configurations in which the radially outer edge of the lens and the inner surface of the lens barrel are in line contact in a cross section along the optical axis direction, where (a) is an enlarged cross-sectional view of the essential parts of a biconvex lens, (b) is an enlarged cross-sectional view of the essential parts of a meniscus lens, and (c) is an enlarged cross-sectional view of the essential parts of a biconcave lens, (d) is an enlarged cross-sectional view of the essential parts in a point contact state when the present invention is applied to (a), (e) is an enlarged cross-sectional view of the essential parts in a point contact state when the present invention is applied to (b), and (f) is an enlarged cross-sectional view of the essential parts in a point contact state when the present invention is applied to (c). [Figure 5] 10 is an enlarged view of a main part showing another form of contact point of a lens that comes into point contact with a lens barrel. FIG. [Figure 6] 2 is a schematic cross-sectional view of a camera module having the lens unit of FIG. 1. [Figure 7] 1 is a schematic diagram of a vehicle equipped with an in-vehicle system including a camera module according to an embodiment of the present invention. [Figure 8] 8 is a block diagram showing the configuration of an imaging device that constitutes the in-vehicle system of FIG. 7. FIG. [Figure 9] (a) is a schematic diagram showing a conventional press-fit configuration in which the outer peripheral surface of the lens and the inner peripheral surface of the lens barrel are in line contact in a cross section along the optical axis direction; (b) is a table showing data on the amount of deformation at five measurement points on the surface (R1 surface) of the lens facing the object side in the press-fit configuration of (a); (c) is a graph of the table of (b); (d) is a table showing data on the amount of deformation at five measurement points on the back surface (R2 surface) of the lens facing the image side in the press-fit configuration of (a); and (e) is a graph of the table of (d). [Figure 10] 1(a) is a schematic diagram showing a press-fit configuration in which the radially outer edge of the lens is in point contact with the inner surface of the lens barrel in a cross section along the optical axis direction, and the contact point is located at the portion of the radially outer edge that is closest to the radial center line; 1(b) is a table showing data on the amount of deformation at five measurement points on the surface (R1 surface) of the lens facing the object side in the press-fit configuration of 1(a); 1(c) is a graph of the table of 1(b); 1(d) is a table showing data on the amount of deformation at five measurement points on the back surface (R2 surface) of the lens facing the image side in the press-fit configuration of 1(a); and 1(e) is a graph of the table of 1(d). [Figure 11] (a) is a schematic diagram showing a press-fit form in which the radially outer peripheral end of the lens is in point contact with the inner surface of the lens barrel in a cross-section along the optical axis direction, and the contact point is located at a portion of the radially outer peripheral end that is farthest from the radial center line. (b) is a table showing data on the amount of deformation at five measurement points on the surface (R1 surface) facing the object side of the lens in the press-fit form of (a). (c) is a graph of the table in (b). (d) is a table showing data on the amount of deformation at five measurement points on the back surface (R2 surface) facing the image side of the lens in the press-fit form of (a). (e) is a graph of the table in (d). [Figure 12] (a) is a schematic diagram showing a press-fit form in which the radially outer peripheral end of the lens is in point contact with the inner surface of the lens barrel in a cross-section along the optical axis direction, and the contact point is located at a portion of the radially outer peripheral end that is farther from the radial center line than in the case of FIG. 9 and closer to the radial center line than in the case of FIG. 10. (b) is a table showing data on the amount of deformation at five measurement points on the surface (R1 surface) facing the object side of the lens in the press-fit form of (a). (c) is a graph of the table in (b). (d) is a table showing data on the amount of deformation at five measurement points on the back surface (R2 surface) facing the image side of the lens in the press-fit form of (a). (e) is a graph of the table in (d). [Figure 13] (a) is an enlarged cross-sectional view of the main part of a conventional lens unit (cross-sectional view along the optical axis) in which the outer peripheral surface of the lens and the inner peripheral surface of the lens barrel are in line contact. (b) is an enlarged view of part Y in (a).

Embodiments for Carrying Out the Invention

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment can realize a highly reliable system, particularly in a sensing system, and contributes to the development of resilient infrastructure. The target is "9.1 Develop quality, reliable, sustainable and resilient infrastructure, including regional and transborder infrastructure, to support economic development and human well-being, with a focus on affordable and equitable access for all," which is one of the Sustainable Development Goals (SDGs) advocated by the United Nations. The lens unit of the present embodiment described below is particularly for use in a camera module such as an in-vehicle camera, and is fixedly installed on the exterior surface of the vehicle, with wiring drawn into the vehicle and connected to a display or other devices. Furthermore, hatching of the lenses is omitted in Figures 1 to 12.

[0024] 1 shows a lens unit 11 according to one embodiment of the present invention. As shown in the figure, lens unit 11 of this embodiment includes a cylindrical lens barrel 12 made of resin, a plurality of lenses arranged in an internal storage space S of lens barrel 12, for example, six lenses consisting of, from the object side, a first lens 13, a second lens 14, a third lens 15, a fourth lens 16, a fifth lens 17, and a fifth lens 18, and an aperture member 22. These lenses 13 to 18 and aperture member 22 are arranged partially via a spacer 30 that separates lenses 14, 15, 17, and 18 from one another in the optical axis direction.

[0025] In this embodiment, the diaphragm member 22 is located between the third lens 15 and the spacer 30, and serves as an "aperture diaphragm" that limits the amount of transmitted light and determines the F-number, which is an index of brightness, or a "light blocking diaphragm" that blocks light rays that cause ghosts and light rays that cause aberrations. An in-vehicle camera equipped with such a lens unit 11 comprises the lens unit 11, a substrate having an image sensor (not shown), and an installation member (not shown) for installing the substrate on a vehicle such as an automobile.

[0026] The multiple lenses 13, 14, 15, 16, 17, and 18 incorporated and housed within the inner housing space S of the lens barrel 12 are stacked and arranged with their optical axes aligned. The lenses 13, 14, 15, 16, 17, and 18 are aligned along a single optical axis O to form a lens group L used for imaging. In this case, the two lenses, the fourth and fifth lenses 16 and 17, located on the image side form a cemented lens (a laminated lens) 40. The first lens 13, located closest to the object, that constitutes the lens group L is a spherical glass lens having a convex surface facing the object side and a concave surface facing the image side, and at least one of the other lenses 14, 15, 16, 17, and 18 is also a glass lens. In this embodiment, all of the lenses 13, 14, 15, 16, 17, and 18 are glass lenses, but this is not a limitation. At least one of the lenses 13, 14, 15, 16, 17, and 18 may be a resin lens. The surfaces of the lenses 13, 14, 15, 16, 17, and 18 may be provided with an anti-reflection film, a hydrophilic film, a water-repellent film, or the like, as needed.

[0027] A substantially cylindrical cap 23 serving as a fastening member is threadedly attached to the object-side end 12b (the upper end in FIG. 1 ) of the lens barrel 12, and this cap 23 secures the first lens 13 to the object-side end 12b of the lens barrel 12. Specifically, a female thread 23a formed on the inner peripheral surface of the peripheral side wall of the cap 23 is threadedly engaged with a male thread 12a formed on the outer peripheral surface of the object-side end 12b of the lens barrel 12, and a radially inner peripheral edge 23b of the flange-like upper end of the cap 23 is abutted against the outer peripheral edge of the surface of the first lens 13 facing the object side. By tightening this cap 23, the first lens 13 is secured to the object-side end 12b, and the lens group L is held in the optical axis direction within the lens barrel 12. Note that if the lens barrel is made of resin, the first lens 13 may be secured not by the cap 23 but by a caulking portion provided at the image-side end of the lens barrel and caulked radially inward.

[0028] In addition, an inner flange portion 24 having an opening with a diameter smaller than that of the sixth lens 18 is provided at the image side end (the lower end in Figure 1) of the lens barrel 12, and the multiple lenses 13, 14, 15, 16, 17, and 18 that make up the lens group L and the aperture member 22 are sandwiched and held between this inner flange portion 24 and the cap 23 in the optical axis direction.

[0029] Additionally, outer peripheral side surface 13a of first lens 13 is provided with a stepped reduced diameter portion 13aa where the diameter is reduced on the image side of lens 13, and a sealing member such as an O-ring 26 is attached to this reduced diameter portion 13aa. O-ring 26 is compressed radially between outer peripheral side surface 13a of first lens 13 and the inner peripheral surface of object-side end 12b of lens barrel 12, thereby sealing the gap between object-side end 12b of lens barrel 12 and first lens 13, thereby preventing fine particles such as water and dust from entering lens barrel 12 from the object-side end of lens unit 11.

[0030] Two flanges 25A, 25B are provided on the outer peripheral wall surface (hereinafter simply referred to as the side wall) 12c of the lens barrel 12. These flanges 25A, 25B are provided in a brim-like shape so as to protrude radially outward from the lens barrel 12 and can be used to attach the lens unit 11 to other components. In this case, for example, a covering case or the like is attached to the first flange 25A located on the object side, while the second flange 25B located on the image side is used for positioning the lens barrel 12 when installing it in the vehicle-mounted camera. This positioning allows precise control of the distance between a package sensor (image pickup element; image pickup sensor) 304 (described later) located at the imaging position of the lens group L and the lenses 13, 14, 15, 16, 17, and 18. Depending on the configuration of the camera, two flanges are not necessary; only flange 25B, which is used when installing the lens barrel 12 in the vehicle-mounted camera body, may be used.

[0031] Furthermore, in this embodiment, the four glass lenses 14, 15, 17, and 18, excluding first lens 13 and fourth lens 16 that does not contact lens barrel 12, are assembled into lens barrel 12 by press-fitting, and in the cross section shown along the optical axis O, their radially outer edges 14a, 15a, 17a, and 18a are in point contact with inner surface 12d of lens barrel 12. In particular, in this embodiment, the radially outer edges 14a, 15a, 17a, and 18a of these lenses 14, 15, 17, and 18 that are in point contact with lens barrel 12 form arcs in the cross section along the optical axis O, and the vertices of these arcs are in point contact with inner surface 12d of lens barrel 12.

[0032] Furthermore, in this embodiment, lenses 14, 15, 17, and 18, which are in point contact with lens barrel 12 in a cross section along the optical axis O, also have their radially outer ends 14a, 15a, 17a, and 18a in point contact with inner surface 12d of lens barrel 12 (point contact with lens barrel 12 in the circumferential direction) in a cross section perpendicular to the optical axis O, as shown in FIG. 2, thereby forming a gap C between them and inner surface 12d of lens barrel 12 in the radial direction. Note that FIG. 2 shows the point contact state of second lens 14 as an example (showing a cross section perpendicular to the optical axis at the position of second lens 14 of lens unit 11 in FIG. 1). In particular, in this embodiment, such a point contact state is achieved by press-fitting lenses 14, 15, 17, and 18 with circular cross sections into lens barrel 12 whose inner peripheral surface is polygonal, as shown in FIG. 2, but is not limited to this.

[0033] 3(a) is an enlarged cross-sectional view (cross-sectional view along the optical axis) of a main part showing a state in which another lens A (a lens that makes point contact with the lens barrel 12 in a cross section along the optical axis O) that can constitute the lens group L of the lens unit 11 of FIG. 1 is press-fitted into the lens barrel 12, and FIG. 3(b) is an enlarged view of portion X in FIG. 3(a). As shown in the figure, these lenses A are biconvex lenses that have an annular outer peripheral flange Ab on their radially outer sides, and whose arc-shaped radial outer peripheral edge AA makes point contact with the inner surface 12d of the lens barrel 12, with the contact point AAa, which is the vertex of the arc, located on the radial centerline L1, which is the perpendicular bisector of a line segment MN along the optical axis O that defines the lens thickness dimension D at the center of the lens A.

[0034] 4(a) to 4(c) show conventional lens press-fitting configurations in which the radially outer edge of lens A and the inner surface 12d of the lens barrel 12 make line contact in a cross section along the optical axis O. (a) is an enlarged cross-sectional view of a main portion of a biconvex lens, (b) is an enlarged cross-sectional view of a main portion of a meniscus lens, and (c) is an enlarged cross-sectional view of a main portion of a biconcave lens. Each lens A has a linear portion Aa on the side end surface (edge) of its annular outer flange Ab that fits in line contact with the inner surface 12d of the lens barrel 12, which extends linearly along the optical axis O. In contrast, (d) of FIG. 4(a) is an enlarged cross-sectional view of a main portion in a point contact state when the present invention is applied to (a) of FIG. 4(e) is an enlarged cross-sectional view of a main portion in a point contact state when the present invention is applied to (b) of FIG. 4(f) is an enlarged cross-sectional view of a main portion in a point contact state when the present invention is applied to (c) of FIG. 4(c). As in the case of Figure 3, the radially outer edge AA of each lens A, which forms an arc, is in point contact with the inner surface 12d of the lens barrel 12, and the contact point AAa, which is the vertex of the arc, is located on the radial center line L1.

[0035] Figure 5 shows other configurations of the contact point AAa of lens A, which makes point contact with the lens barrel 12 in a cross section along the optical axis O. The lens A shown in Figure 5(a) is a biconvex lens in which the curvature of the object-facing surface Ac is greater than the curvature of the image-facing back surface Ad. The radially outermost edge AA of the outer flange Ab is made up of a combination of straight lines and curves (e.g., arcs), and the radially outermost portion of the radially outer edge AA, i.e., the contact point AAa with the lens barrel 12, is located on the radial centerline L1. In this case, the position of the contact point AAa is biased toward the surface Ac. The lens A shown in Figure 5(b) is a biconcave lens in which the curvature of the object-facing surface Ac is smaller than the curvature of the image-facing back surface Ad. The radially outermost edge AA of the outer flange Ab is made up of a combination of straight lines and curves (e.g., arcs), and the radially outermost portion of the radially outer edge AA, i.e., the contact point AAa with the lens barrel 12, is located on the radial centerline L1. In this case, the position of contact point AAa is biased toward the side of surface Ac. Lens A shown in Figure 5(c) is a meniscus lens in which the curvature of the surface Ac facing the object side is greater than the curvature of the back surface Ad facing the image side, and the radially outermost portion of radially outer peripheral edge AA of outer peripheral flange Ab is arc-shaped, and the contact point AAa with lens barrel 12 is the edge of radially outer peripheral edge AA closest to radial centerline L1.

[0036] 6 is a schematic cross-sectional view of a camera module 300 of this embodiment having a lens unit 11 having the configuration shown in Fig. 1. As shown in the figure, this camera module 300 is configured to have the lens unit 11 according to Fig. 1 to which a filter 99 is attached.

[0037] Camera module 300 includes a front case (camera case) 301, which is an exterior component, and a mount (base) 302 that holds lens unit 11. Camera module 300 also includes a seal member 303 and a package sensor (imaging element; imaging sensor) 304.

[0038] Front case 301 is connected to first flange 25A via seal member (O-ring) 303, and is a member that exposes the object-side end of lens unit 11 while covering the other portions to provide waterproofing. Mount 302 is disposed inside front case 301, with its object-side end 302a abutting and adhering to image-side surface 25Ba of second flange 25B, and its image-side end 302b mounted and fixed on substrate 306. Furthermore, seal member 303 is a member interposed between the inner surface of front case 301 and the object-side surface of first flange 25A of lens barrel 12, and is a member that maintains airtightness inside front case 301.

[0039] Package sensor 304 is disposed on substrate 306 inside mount 302, and is positioned to receive the image of an object formed by lens unit 11. Package sensor 304 also includes a CCD, CMOS, or the like, and converts the light that is collected and reaches it through lens unit 11 into an electrical signal. The converted electrical signal is then converted into analog data or digital data, which are components of the image data captured by the camera.

[0040] FIG. 7 schematically illustrates a vehicle 40 equipped with an in-vehicle system including an imaging device 50 including the camera module 300 of FIG. 6 . As illustrated, the imaging device 50 can be mounted on the vehicle 40, and FIG. 7 illustrates an example of the mounting position of the imaging device 50 on the vehicle 40. The imaging device 50 mounted on the vehicle 40 can also be called an in-vehicle camera and can be installed in various locations on the vehicle 40. For example, the first imaging device 50a may be installed on or near the front bumper as a camera that monitors the front of the vehicle 40 while the vehicle 40 is traveling. The second imaging device 50b that monitors the front may be installed near an inner rearview mirror inside the vehicle 40. The third imaging device 50c may be installed on the dashboard or in the instrument panel as a camera that monitors the driver's driving status. The fourth imaging device 50d may be installed at the rear of the vehicle 40 to monitor the rear of the vehicle 40. The imaging devices 50a and 50b can be called front cameras. The third imaging device 50c can be called an in-camera. The fourth imaging device 50d can be called a rear camera. The imaging device 50 is not limited to these, and can include imaging devices installed in various positions, such as a left side camera that captures images of the left rear side and a right side camera that captures images of the right rear side.

[0041] An image signal of an image captured by the imaging device 50 may be output to an information processing device 42 and / or a display device 43, etc., within the vehicle 40. The information processing device 42 and the display device 43, together with the imaging device 50, constitute an in-vehicle system. The information processing device 42 within the vehicle 40 includes a device that processes the image signal acquired by the imaging device 50, recognizes the image, and assists the driver in driving. The information processing device 42 may include, but is not limited to, a navigation system, a collision damage mitigation braking system, a vehicle-to-vehicle distance control device, and a lane departure warning system. The display device 43 displays the image processed and output by the information processing device 42, but can also receive the image signal directly from the imaging device 50. The display device 43 may be, but is not limited to, a liquid crystal display (LCD), an organic electroluminescence (EL) display, or an inorganic EL display. The display device 43 can display to the driver an image signal output from the imaging device 50, which captures an image from a position difficult for the driver to view, such as a rear camera.

[0042] Fig. 8 shows the configuration of an imaging device that constitutes the in-vehicle system of Fig. 7. As shown in the figure, imaging device 50 according to one embodiment includes control unit 52, storage unit 54, and camera module 300 shown in Fig. 2 described above.

[0043] The control unit 52 controls the camera module 300 and processes the electrical signal output from the image sensor 304 of the camera module 300. The control unit 52 may be configured as, for example, a processor. The control unit 52 may also include one or more processors. The processor may include a general-purpose processor that loads a specific program to execute a specific function, and a dedicated processor specialized for a specific process. The dedicated processor may include an application-specific integrated circuit (IC). An application-specific IC is also called an application-specific integrated circuit (ASIC). The processor may include a programmable logic device. A programmable logic device is also called a programmable logic device (PLD). The PLD may include a field-programmable gate array (FPGA). The control unit 52 may be either a system-on-a-chip (SoC) or a system in a package (SiP) in which one or more processors work together.

[0044] The storage unit 54 stores various information or parameters related to the operation of the imaging device 50. The storage unit 54 may be configured with, for example, a semiconductor memory or the like. The storage unit 54 may function as a work memory for the control unit 52. The storage unit 54 may store captured images. The storage unit 54 may store various parameters, etc., used by the control unit 52 to perform detection processing based on the captured images. The storage unit 54 may be included in the control unit 52.

[0045] As described above, the camera module 300 captures an image of a subject formed via the lens unit 11 with the image sensor 304 and outputs the captured image. The image captured by the camera module 300 is also referred to as a captured image.

[0046] The image sensor 304 may be configured, for example, as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device). The image sensor 304 has an imaging surface on which a plurality of pixels are arranged. Each pixel outputs a signal specified by a current or voltage according to the amount of incident light. The signal output by each pixel is also referred to as imaging data.

[0047] The imaging data may be read by the camera module 300 for all pixels and imported into the control unit 52 as a captured image. A captured image read out for all pixels is also referred to as a maximum captured image. The imaging data may be read by the camera module 300 for some pixels and imported as a captured image. In other words, the imaging data may be read out from pixels in a predetermined capture range. The imaging data read out from pixels in the predetermined capture range may be imported as a captured image. The predetermined capture range may be set by the control unit 52. The camera module 300 may acquire the predetermined capture range from the control unit 52. The imaging element 304 may capture an image of a predetermined capture range from the subject image formed via the lens unit 11.

[0048] As described above, according to this embodiment, in a cross section along the optical axis O, radial outer ends 14a, 15a, 17a, 18a (radial outer ends AA) of lenses 14, 15, 17, 18 (lens A) are in point contact with inner surface 12d of lens barrel 12. This reduces the pressure acting on lenses 14, 15, 17, 18 (lens A) and suppresses deformation of lenses 14, 15, 17, 18 (lens A) in a unique press-fit configuration in which glass lenses 14, 15, 17, 18 (lens A) are press-fitted into resin lens barrel 12. This makes it possible to obtain desired optical characteristics without degrading optical performance.

[0049] The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the shapes of the lenses and lens barrels in the present invention are not limited to those in the above-described embodiments. Furthermore, some or all of the above-described embodiments may be combined, or part of the configuration of one of the above-described embodiments may be omitted, without departing from the spirit of the present invention. [Explanation of symbols]

[0050] 11 Lens unit 12 Telescope tube 12d Inner surface 13, 14, 15, 16, 17, 18 Lenses 14a,15a,17a,18a Radial outer peripheral end 40 vehicles 42 Information processing equipment (processing equipment) 43 Display device 50 Imaging device 52 Control section 300 Camera Module 304 Image sensor A lens AA Radial outer edge AAa contact point L lens group L1 Radial center line S Inner storage space

Claims

1. A lens unit comprising: a cylindrical lens barrel that forms an internal storage space for storing and holding lenses; and a lens group that is incorporated into the internal storage space of the lens barrel and that is composed of a plurality of lenses arranged along an optical axis, the lens barrel is made of resin, a first lens that is positioned closest to the object and that constitutes the lens group is attached without being press-fitted into the lens barrel in a state where the gap between the first lens and the lens barrel is sealed by a seal member that is attached between the outer peripheral side surface of the first lens and the inner peripheral surface of the lens barrel, At least two lenses of the lens group, excluding the first lens, are made of glass, are assembled into the lens barrel by press-fitting, have annular flanges on their radially outer sides, and are in point contact with the inner surface of the lens barrel at one vertex of an arc-shaped radially outer edge of the flange in a cross section along the optical axis direction, The lens unit is characterized in that the point contact is achieved by press-fitting the circular lens into the polygonal inner peripheral surface of the lens barrel in a cross section perpendicular to the optical axis.

2. 2. The lens unit according to claim 1, wherein the contact point of the lens that comes into point contact with the lens barrel is located at the radially outer peripheral end portion closest to the radial center line, which is the perpendicular bisector of a line segment along the optical axis direction that defines the lens thickness dimension at the center of the lens, in a cross section along the optical axis direction.

3. 3. The lens unit according to claim 2, wherein the contact point is located on the radial centerline.

4. 4. A camera module comprising: the lens unit according to claim 1; and an image sensor that converts light collected through a lens group of the lens unit into an electric signal.

5. An in-vehicle system mounted on a vehicle, an imaging device comprising: the camera module according to claim 4; and a control unit that controls the camera module and processes an electrical signal output from the imaging element of the camera module; a processing device that processes an image signal acquired by the imaging device; a display device that displays an image processed and output by the processing device; An in-vehicle system comprising:

6. A vehicle equipped with the on-board system according to claim 5.

Images