JP7564271B2 - Lens units and camera modules - Google Patents

Description

The present invention relates to a light shield, a lens unit, and a camera module equipped with this lens unit.

In recent years, automobiles have been equipped with on-board cameras to support parking and prevent collisions through image recognition, and further applications to autonomous driving have been attempted. One example of a lens unit used in such on-board cameras is known from Patent Document 1. In this lens unit, four lenses are held in a lens barrel in a state where the optical axis directions of the lenses are aligned in a row. In addition, an aperture member (light shielding plate) is provided between the lenses.
The light blocking plate is formed in an annular plate shape with a circular opening (inner diameter hole) in the center, and limits the range of light passing through, and by arranging the diaphragm member in an appropriate position, flare and ghosting can be appropriately suppressed, and the optical performance of the lens unit can be improved. Therefore, in order to improve the optical performance of the lens unit, it is important to arrange the light blocking plate in an appropriate position.

The light shielding plate disposed between the lenses is sandwiched between flanges provided on the outer periphery of the portion of each lens that has a lens function, and thus its position in the axial direction of the lens barrel is determined. In addition, the light shielding plate is sometimes positioned in the axial direction of the lens barrel by abutting one surface of the light shielding plate against the lens flange and the other surface against a member other than the lens, rather than abutting against the lens on both sides.
Furthermore, the light blocking plate has its outer periphery abutting against the inner periphery of the barrel of the lens unit, thereby determining its position in the radial direction of the barrel.

JP 2008-233512 A

Incidentally, a plurality of light-shielding plates as described above are often provided in the lens barrel of one type of lens unit. In this case, a plurality of light-shielding plates of the same type having the same shape and size may be provided, but more often, a plurality of light-shielding plates of different shapes, sizes, etc. are provided.
Conventional light shielding plates have a simple shape, such as a circular outer edge, and the outer diameters are almost the same. If the diameters of the inner holes are close, it is difficult to distinguish between multiple types of light shielding plates. This has led to problems when installing multiple types of light shielding plates in a lens barrel, such as the wrong type of light shielding plate being installed, or light shielding plates that should be installed in the lens barrel of a different type of lens unit being mistakenly mixed in. In particular, during manual assembly work, the worker must visually distinguish the type of light shielding plate, and a solution to this problem was needed.

In addition, while conventional light shielding plates have different shapes and sizes of notches on their outer periphery, allowing workers to distinguish between the various types of light shielding plates visually or through image processing, the presence of the notches not only makes it difficult to position the light shielding plate in the lens barrel diameter direction, but also, in recent years, light shielding plates have been supplied to lens unit assembly lines using vibration-type parts feeders, in which case the light shielding plates may become entangled with each other through the notches, damaging each other and adversely affecting the light shielding performance. Because the light shielding plate limits the range of light that passes through, if the scratches or notches as described above become large, light may escape from the outer periphery of the light shielding plate, causing ghost and flare problems.

The present invention has been made in consideration of the above circumstances, and aims to provide a light shielding plate that can be fitted to the lens barrel of a lens unit without fail, can be reliably positioned in the radial direction of the lens barrel (the direction perpendicular to the optical axis), and can prevent light from escaping from the outer periphery, a lens unit equipped with such a light shielding plate, and a camera module equipped with this lens unit.

In order to solve the above problems, the light shielding plate of the present invention is a light shielding plate provided in a lens unit,
The outer edge of the light shielding plate is
A plurality of arcuate lines having the same radius with respect to the center of the light shielding plate, the same length in the circumferential direction, and arranged at equal intervals in the circumferential direction;
a connecting line connecting ends of the arc lines adjacent to each other in the circumferential direction,
The connecting line is disposed inside an imaginary circle that is concentric with and has the same diameter as the arc line.

In the present invention, since the outer edge of the light shielding plate has a plurality of arc lines and connecting lines connecting the ends of the arc lines adjacent in the circumferential direction, by changing the number of arc lines and/or connecting lines, the circumferential length, and the circumferential interval for each type of light shielding plate, it is possible to reliably distinguish between multiple types of light shielding plates. Therefore, it is possible to install multiple types of light shielding plates on the lens barrel of the lens unit without any mistakes.
In addition, the outer edge of the light-shielding plate has a plurality of arc lines that have the same radius from the center of the light-shielding plate, are equal in circumferential length, and are arranged at equal intervals in the circumferential direction.Therefore, by abutting the outer edge portion formed by these arc lines against the inner surface of the lens barrel, positioning in the radial direction of the lens barrel (orthogonal to the optical axis) can be reliably achieved.
Furthermore, since the outer edge of the light shielding plate is provided with a plurality of arc lines and connecting lines connecting the ends of adjacent arc lines in the circumferential direction, the light shielding plates are less likely to become entangled when supplied to the lens unit assembly line, and are less likely to damage the light shielding plates or adversely affect the light shielding performance, compared to when the outer edge of the light shielding plate is provided with notches. Therefore, it is possible to suppress the escape of light from the outer periphery of the light shielding plate, compared to when the outer edge of the light shielding plate is provided with notches.

In addition, in the above-mentioned configuration of the present invention, the number of the arc lines may be 3 or more and 6 or less, and more preferably, the number of the arc lines is 5 or 6.

When the number of arc lines is two or less, as the circumferential length of the arc lines increases, the outer edge of the light-blocking plate approaches the circle of the outer edge of conventional light-blocking plates, and even when the number is seven or more, the outer edge of the light-blocking plate approaches the circle of the outer edge of conventional light-blocking plates, making it difficult to distinguish between multiple types of light-blocking plates.
Therefore, by making the number of arc lines three or more and six or less, it is possible to reliably distinguish between multiple types of light-shielding plates, and by making the number of arc lines five or six, the light-shielding plates are less likely to become tangled when supplied to the lens unit assembly line, and the leakage of light from the outer periphery of the light-shielding plate can be further suppressed.

In the above-described configuration of the present invention, the connecting line may be formed of one straight line, a plurality of straight lines, one curved line, a plurality of curved lines, or a combination of the straight lines and the curved lines.
Here, the combination of straight lines and curves includes a combination of one straight line and one curve, a combination of one straight line and multiple curves, a combination of multiple straight lines and one curve, and a combination of multiple straight lines and multiple curves.

This configuration allows for a greater number of different types of connecting lines, making it easier to distinguish between the various types of light shielding plates when they are installed on the telescope barrel.

The light-shielding plate of the present invention may be formed by etching a flat plate, or may be formed by punching out a flat plate.
When the light-shielding plate is formed by etching, the multiple arc lines that make up the outer edge of the light-shielding plate and the connecting lines that connect the ends of adjacent arc lines in the circumferential direction can be formed more easily and accurately than when the light-shielding plate is formed by punching.

The lens unit of the present invention comprises a lens barrel, a lens arranged on the inner circumference side of the lens barrel, and a light shielding plate arranged on the inner circumference side of the lens barrel, and is characterized in that a plurality of the light shielding plates are arranged on the inner circumference side of the lens barrel, and some of the plurality of the light shielding plates are the light shielding plates described above.

In the present invention, some of the multiple light-shielding plates arranged on the inner circumference side of the lens barrel are the light-shielding plates described above, so the light-shielding plates can be arranged on the inner circumference side of the lens barrel without fail, and the remaining light-shielding plates can be arranged as conventional light-shielding plates with circular outer peripheries. Furthermore, by abutting the outer edge portion of the light-shielding plate formed by the arc line with the inner circumference surface of the lens barrel, the light-shielding plate can be reliably positioned in the lens barrel diameter direction (direction perpendicular to the optical axis). Furthermore, it is possible to prevent light from escaping from the outer periphery of the light-shielding plate.

Another lens unit of the present invention includes a lens barrel, a lens arranged on the inner circumference side of the lens barrel, and a light shielding plate arranged on the inner circumference side of the lens barrel, and is characterized in that multiple types of the light shielding plates described above are arranged on the inner circumference side of the lens barrel.

In the present invention, since multiple types of light-shielding plates as described above are arranged on the inner circumference side of the lens barrel, multiple types of light-shielding plates can be arranged on the inner circumference side of the lens barrel without fail. Also, by abutting the outer edge portion formed by the arc line of the light-shielding plate with the inner circumference surface of the lens barrel, the light-shielding plate can be reliably positioned in the lens barrel diameter direction (direction perpendicular to the optical axis). Furthermore, it is possible to suppress the escape of light from the outer circumference of the light-shielding plate.

The camera module of the present invention is characterized by having the above-mentioned lens unit and an imaging element that captures an image formed by the lens unit.

The present invention can achieve the same effects as the lens unit.

The present invention makes it possible to install multiple types of light shielding plates on the lens barrel of a lens unit without fail, and also ensures reliable positioning in the radial direction of the barrel (the direction perpendicular to the optical axis), thereby preventing light from escaping from the outer periphery.

1 is a schematic cross-sectional view showing an embodiment of a lens unit of the present invention. 10 is a plan view showing an irregular light-shielding plate provided on the lens barrel of the lens unit according to the first embodiment. FIG. 2 is a plan view showing a circular light blocking plate provided on the lens barrel of the lens unit according to the first embodiment. FIG. FIG. 3 is an enlarged view of a main part in FIG. 2 . 13A shows a plan view of the main part of the light-shielding plate when the connecting lines are straight, and FIG. 13B shows a plan view of the main part of the light-shielding plate when the connecting lines are curved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a lens unit according to an embodiment of the present invention.
The lens unit 10 of the present embodiment can be used, for example, in an on-vehicle camera, but is not limited to being used in on-vehicle cameras and can also be used in other cameras.
The lens unit 10, together with an imaging element, a wiring board, a signal processing circuit, a flexible wiring sheet, a connector, and the like, constitutes a camera module. Note that the camera module refers to one that includes at least a lens unit and an imaging element. In the camera module of this embodiment, an imaging element (not shown) is disposed on the imaging side of the lens unit 10 (the side on which the lens unit 10 forms an image), and it is possible to capture an image formed by the lens unit 10.

As shown in FIG. 1, the lens unit 10 of this embodiment includes a cylindrical lens barrel 11, five lenses 12, 13, 14, 15, and 16, two light-shielding plates (aperture members) 18 and 19, three spacers 20, 21, and 22, an optical filter 23, and an annular pressing member 24.

The lens barrel 11 is provided with a locking portion 11a formed on the inner circumference of one end, which is the end on the image side, protruding inward so that the inner diameter becomes smaller. In addition, the lens barrel 11 is formed with a male thread on the outer circumference of the other end, which is the end on the object side. The male thread is shaped to screw into a female thread formed on the inner circumference of the holding member 24, and the holding member 24 is fixed to the end on the object side of the lens barrel 11 by screwing the male thread and the female thread. In addition, the holding member 24 is provided with a locking portion 24a formed on the inner circumference protruding inward so that the inner diameter becomes smaller.

On the inner circumference side of the lens barrel 11, the lens 12, the spacer 20, the light shielding plate 18, the lens 13, the spacer 21, the light shielding plate 19, the lens 14, the lens 15, the spacer 22, and the lens 16 are arranged in this order from the object side toward the image side. Adjacent members are in contact with each other. The peripheral portion of the object side surface of the lens 12 is in contact with the locking portion 24a of the pressing member 24, and the peripheral portion of the image side surface of the lens 16 is in contact with the locking portion 11a. In other words, the five lenses 12, 13, 14, 15, and 16, the two light shielding plates 18 and 19, and the three spacers 20, 21, and 22 are arranged in a state sandwiched between the locking portion 24a and the locking portion 11a.
Further, an optical filter 23 is disposed on the outer side of the locking portion 11a of the lens barrel 11 in the optical axis direction.

The five lenses 12, 13, 14, 15, and 16 are disposed on the inner circumference side of the lens barrel 11 with their respective optical axes aligned, and are fixed and supported by the lens barrel 11. That is, the lenses 12, 13, 14, 15, and 16 are aligned along one optical axis, thereby constituting one lens group 25 used for imaging. When simply referring to the optical axis below, this refers to the optical axis of each of the lenses 12, 13, 14, 15, and 16 as well as the optical axis of the lens group 25.
In the lens group 25, the first and second lenses 12 and 13 from the object side are glass lenses (lenses made of glass), and the third, fourth and fifth lenses 14, 15 and 16 are resin lenses (lenses made of resin). Furthermore, each of the lenses 12, 13, 14, 15 and 16 may be either a glass lens or a resin lens.

The light shielding plates 18 and 19 are each formed in the shape of a thin plate from a metal such as austenitic stainless steel (SUS304, etc.) and are blackened to enhance the effect of suppressing flare and ghosts.
As shown in FIG. 2, the light shielding plate 18 is formed such that the outer edge is not circular but is irregularly shaped like an annular shape, and has an inner diameter hole 18a in the radial center for passing light therethrough.
As shown in FIG. 3, the light shielding plate 19 has an outer circumferential edge formed in a circular ring shape, and has an inner diameter hole 19a in the radial center for passing light therethrough.
The inner diameter hole 18a is slightly longer than the inner diameter hole 19a, so that it is difficult to distinguish between the light blocking plates 18 and 19 based on the difference in the diameters of the inner diameter holes 18a and 19a.
In addition, since the outer edges (outer peripheral edges) of both light-shielding plates 18, 19 abut or are close to the same inner peripheral surface of the lens barrel 11, if the outer peripheral edges of both light-shielding plates 18, 19 are made circular, it would be difficult to distinguish between the light-shielding plates 18, 19.

For this reason, in this embodiment, the outer edge of the light blocking plate 18 is not circular but is formed into an irregular shape as described below.
That is, as shown in Fig. 2, the outer edge 31 of the light shielding plate 18 in a plan view (axial view) has six arc lines 32 that have the same radius r with respect to the center O of the light shielding plate 18, are equal in circumferential length, and are arranged at equal intervals in the circumferential direction, and connecting lines 33 that connect ends 32a, 32a of adjacent arc lines 32, 32 in the circumferential direction. The radius r of the arc lines 32 is equal to the radius r of the light shielding plate 19 shown in Fig. 2.

The six arc lines 32 are arranged at 60° intervals in the circumferential direction, and similarly, the six connecting lines 33 are arranged at 60° intervals in the circumferential direction. Therefore, the light blocking plate 18 is point-symmetric about its center O.
The circumferential length of the arc line 32 is set so that the angle between the line segments connecting both ends 32a, 32a of the arc line 32 and the center O is 30 degrees to 50 degrees, preferably 35 degrees to 48 degrees. If the angle exceeds 50 degrees, the arc line 32 is too short, which hinders radial positioning, and if the angle is less than 30 degrees, it becomes difficult to distinguish the arc line 32 from the light shielding plate 19, the outer periphery of which is circular.

In this embodiment, the number of arc lines 32 is six, but it is preferable that the number of arc lines be three or more and six or less.
When the number of arc lines 32 is two or less, as the circumferential length of the arc lines 32 becomes longer, the outer edge 31 of the light-shielding plate 18 approaches the circle on the outer edge of a conventional light-shielding plate, such as the light-shielding plate 19 shown in Figure 2, and even when the number of arc lines 32 is seven or more, the outer edge of the light-shielding plate 31 approaches the circle on the outer edge of a conventional light-shielding plate, such as the light-shielding plate 19 shown in Figure 2, making it difficult to distinguish between the multiple types of light-shielding plates 18, 19.

The outer diameter of the light shielding plate 18, i.e., the radial distance (2r) between the radially opposing arc lines 32, 32, approximately matches the inner diameter of the lens barrel 11, and the outer peripheral surface of the light shielding plate 18 is in close proximity to or in contact with the inner peripheral surface 11b of the lens barrel 11. In other words, no other members are sandwiched between the outer peripheral surface of the light shielding plate 18 and the inner peripheral surface 11b of the lens barrel 11, and only a very small gap is provided, so that the light shielding plate is fitted into the lens barrel 11. This allows the light shielding plate 18 to be positioned in a direction perpendicular to the optical axis (the radial direction of the lens barrel 11).

As shown in FIG. 2, all six connecting lines 33 are arranged inside an imaginary circle 40 that is concentric with and has the same diameter as the arc line 32, and each connecting line 33 is closer to the center O of the imaginary circle 40 as it approaches the center of its length.
4, the connecting line 33 is composed of two straight lines 33a, 33a. The two straight lines 33a, 33a are arranged symmetrically with respect to a line segment L that passes through a central point 33d of the connecting line 33 and the center of the imaginary circle 40.
A predetermined radius of curvature R is imparted to the connection between the straight line 33a and the arc line 32, and a predetermined radius of curvature R is also imparted to the connection between the straight lines 33a, 33a.
Furthermore, the connecting line 33 is not limited to the above. For example, as shown in Fig. 4(a), the connecting line 33 may be formed of a single straight line 33a. In this case, a predetermined radius of curvature R is imparted to the connection between the straight line 33a and the arc lines 32 on both sides. Furthermore, as shown in Fig. 4(b), the connecting line 33 may be formed of a single curved line 33b. In this case as well, a predetermined radius of curvature R is imparted to the connection between the curved line 33b and the arc lines 32 on both sides.

Furthermore, although not shown in the drawings, the connecting line may be formed of a plurality of straight lines, a plurality of curved lines, or a combination of straight lines and curved lines, including a combination of one straight line and one curved line, a combination of one straight line and multiple curved lines, a combination of multiple straight lines and one curved line, and a combination of multiple straight lines and multiple curved lines.
When forming the connecting lines in this manner, it is preferable to give a predetermined radius of curvature R to the connection between straight lines, the connection between curved lines, and the connection between a straight line and a curved line.
Furthermore, the connecting lines arranged at equal intervals in the circumferential direction of the light blocking plate may all be of the same shape, some of them may have different shapes, or even all of them may have different shapes.

The light blocking plate 18 is formed by etching. Note that the light blocking plate 18 in this embodiment is formed by utilizing wet etching.
The light shielding plate 18 is made by etching both sides of a doughnut-shaped (flat) metal plate with a hole in the center and flat on both sides, which serves as the base of the light shielding plate 18. Specifically, the light shielding plate 18 is formed by etching the outer portion of the outer periphery of the metal plate, the portion outside the outer edge 31 described above.

By forming the light-shielding plate 18 by etching processing, the thickness of the light-shielding plate 18, the multiple arc lines 32 that make up the outer edge 31 of the light-shielding plate 18, and the connecting lines 33 that connect the ends 32a, 32a of adjacent arc lines 32, 32 in the circumferential direction can be easily and precisely formed to the micrometer level.
Furthermore, the etching process makes it possible to freely set the surface roughness of the light-shielding plate 18 to a certain degree during processing. By adjusting the surface roughness, the reflectance of the surface of the light-shielding plate 18 can be reduced.
In addition, in the etching process, a plurality of light blocking plates 18 are connected with bridges and etched at one time.
The bridge is a small connecting portion that does not affect the shape of the light shielding plate 18, and is eventually cut off to separate the plate into a single product. The bridge is preferably provided at the center of the connecting line 33, and two or three bridges are preferably provided per light shielding plate 18.
The light blocking plate 18 may be formed by punching instead of by etching.

In a lens unit equipped with such a light shielding plate 18 and a light shielding plate 19 with a circular outer periphery, as shown in FIG. 1, multiple (two) light shielding plates 18, 19 are arranged on the inner periphery side of the lens barrel 11. In other words, of the two light shielding plates 18, 19, some of the light shielding plates 18 have an irregular outer periphery as described above.

Therefore, according to this embodiment, the light shielding plate 18 has an irregular shape, that is, the outer edge 31 of the light shielding plate 18 has multiple arc lines 32 and connecting lines 33 connecting the ends 32a, 32a of adjacent arc lines 32, 32 in the circumferential direction, while the outer edge of the light shielding plate 19 is formed in a circular shape, so that the two types of light shielding plates 18, 19 can be easily and reliably distinguished from each other. Therefore, multiple types of light shielding plates 18, 19 can be provided on the lens barrel 11 of the lens unit without any mistakes.

In addition, the outer edge 31 of the light-shielding plate 18 has multiple (six) arc lines 32 that have the same radius r relative to the center O of the light-shielding plate 18, are equal in circumferential length, and are arranged at equal intervals in the circumferential direction. Therefore, by abutting the outer edge portion formed by these arc lines 32 against the inner surface 11b of the lens barrel 11, positioning in the lens barrel radial direction (direction perpendicular to the optical axis) can be reliably performed.
Furthermore, since the outer edge 31 of the light shielding plate 18 is provided with a plurality of arc lines 32 and connecting lines 33 connecting the ends 32a, 32a of the arc lines 32, 32 adjacent in the circumferential direction, the light shielding plates 18 are less likely to become entangled when supplied to the assembly line of the lens unit 10, and are less likely to damage the light shielding plates 18 or adversely affect the light shielding performance, compared to when a relatively large notch is provided on the outer circumferential edge of the light shielding plate. Therefore, it is possible to suppress the escape of light from the outer periphery of the light shielding plate 18, compared to when a relatively large notch is provided on the outer periphery of the light shielding plate.

In this embodiment, the case where two light shielding plates 18, 19 are provided on the lens barrel 11 has been described as an example, but the present invention is not limited to this. For example, the lens barrel 11 may be provided with a plurality of other light shielding plates or a plurality of types of light shielding plates in addition to or instead of the light shielding plates 18, 19. In this case, the lens barrel 11 may be provided with a combination of the irregularly shaped light shielding plate as described above and a circular light shielding plate, or the lens barrel 11 may be provided with a plurality of types of irregularly shaped light shielding plates.
When multiple types of irregularly shaped light-shielding plates are provided in the lens barrel 11, the number of arc lines, the circumferential length of the arc lines, the number of connecting lines, the length of the connecting lines, the number and shape of the straight lines and/or curves that make up the connecting lines, etc. can be appropriately changed so that the light-shielding plates can be distinguished from one another.

10 Lens unit 11 Lens barrel 11b Inner peripheral surface (inner peripheral surface of the lens barrel)
12, 13, 14, 16 Lens 18 Light shielding plate 31 Outer edge 32 Arc line 32a End of arc line 33 Connecting line 40 Virtual circle

Claims (6)

A lens unit including a lens barrel, a lens disposed on an inner periphery side of the lens barrel, and a light shield disposed on the inner periphery side of the lens barrel,
A plurality of the light blocking plates are disposed on the inner periphery side of the lens barrel,
Some of the plurality of light-shielding plates are first light-shielding plates,
the first light-shielding plate includes a plurality of arcuate lines whose outer edges have the same radius with respect to the center of the light-shielding plate, have equal circumferential lengths, and are arranged at equal intervals in the circumferential direction; and a plurality of connecting lines connecting ends of the arcuate lines adjacent to each other in the circumferential direction,
the connecting line is disposed inside an imaginary circle that is concentric with the arc line,
the plurality of arc lines and the plurality of connecting lines are disposed in the same plane;
the plurality of connecting lines are formed by straight lines or curves extending from one end to the other end of the circumferentially adjacent arc lines,
Another part of the plurality of light-shielding plates is a second light-shielding plate having a circular outer periphery,
A lens unit, wherein the first light-shielding plate and the second light-shielding plate are distinguishable from each other by their outer shapes. The plurality of arc lines of the first light-shielding plate are composed of three to six arc lines arranged at equal intervals in a circumferential direction,
2. The lens unit according to claim 1, wherein the length of the arc line is set so that an angle between the two ends of the arc line and the center of the virtual circle is in the range of 30 degrees to 50 degrees. the connecting line is closer to the center of the imaginary circle as it approaches a central portion in a length direction of the connecting line,
the connecting line is composed of two straight lines, the two straight lines being arranged symmetrically with respect to a line segment passing through a center point of the connecting line and a center of the imaginary circle,
3. The lens unit according to claim 1, wherein a radius of curvature is imparted to a connection portion between the straight line and the arcuate line, and a radius of curvature is imparted to a connection portion between the straight lines. The lens unit according to claim 1 or 2, characterized in that the connecting line is composed of one straight line, multiple straight lines, one curved line, multiple curved lines, or a combination of the straight lines and the curved lines. 5. The lens unit according to claim 1, wherein a plurality of types of the first light-shielding plates are arranged on the inner periphery of the lens barrel. A camera module comprising the lens unit according to any one of claims 1 to 5 and an image sensor for capturing an image formed by the lens unit.

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