Lens module

Abstract

To provide a lens module capable of adjusting a position of a lens in a direction orthogonal to an optical axis, and capable of suppressing positional deviation of the lens after adjustment.SOLUTION: The lens module includes a first lens, a second lens, a lens holding frame that holds the first lens, and an adjustment member that holds the second lens and adjusts a position orthogonal to an optical axis direction of the second lens, wherein the adjustment member includes a first fitting portion to which the first lens can be fitted and a second fitting portion to which the second lens can be fitted. A center of the second fitting part in an orthogonal plane orthogonal to an optical axis of the second lens is located at a position eccentric with respect to a center of the first fitting part in the orthogonal plane.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a lens module capable of adjusting the eccentricity of a lens. [Background technology]

[0002] In order to reduce the effects of manufacturing errors and assembly variations and improve optical performance, a lens barrel may be provided with an adjustment mechanism that adjusts the position of the lens or lens holding frame in a direction perpendicular to the optical axis.

[0003] A known technique for adjusting the position of a lens in a direction perpendicular to the optical axis is to insert a tool into an opening provided in a lens holder that holds the lens, and press the outer peripheral surface of the lens to move and adjust the lens parallel to the receiving surface (Patent Document 1). Furthermore, after adjustment, the lens is fixed by a pressing member that is fixed to the lens holder and an elastic member that presses the lens against the lens holder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-184352 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology in Patent Document 1 has a configuration in which the lens is fixed by being pressed with a pressing member and an elastic member, so there is a problem in that if a vibration or impact stronger than the pressing force of the pressing member or the elastic member is applied, the lens may shift from its fixed position after adjustment.

[0006] An object of the present invention is to provide a lens module in which the position of the lens in a direction perpendicular to the optical axis can be adjusted, and in which positional deviation of the lens after adjustment can be suppressed. [Means for solving the problem]

[0007] The lens module of the present invention comprises a first lens, a second lens, a lens holding frame that holds the first lens, and an adjustment member that holds the second lens and adjusts the position of the second lens perpendicular to the optical axis direction, wherein the adjustment member has a first fitting portion into which the first lens can be fitted and a second fitting portion into which the second lens can be fitted, and the center of the second fitting portion in an orthogonal plane perpendicular to the optical axis of the second lens is located at a position eccentric to the center of the first fitting portion in the orthogonal plane. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a lens module in which the position of the lens in a direction orthogonal to the optical axis can be adjusted, and in which positional deviation of the lens after adjustment can be suppressed. [Brief explanation of the drawings]

[0009] [Figure 1] Perspective view of the camera module [Figure 2] Exploded perspective view of the camera module [Figure 3] Exploded perspective view of the lens unit [Figure 4] Front and rear views of the eccentricity adjustment member [Figure 5] Cross-section of the lens unit DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. A lens module according to this embodiment will be described below with reference to Figs. 1 to 5. Fig. 1 is an overall view of a camera module equipped with the lens module. Fig. 2 is an exploded perspective view of a camera module equipped with a lens module according to an embodiment.

[0011] The camera module 1 is composed of a lens module 2 and an imaging unit 3.

[0012] The lens module 2 is made up of a lens unit 4 and a lens holder 18. The imaging unit 3 is made up of an imaging element 20 and an imaging board 21. The imaging element 20 is mounted on the imaging board 21. The imaging board 21 is fixed to the lens holder 18 with screws 19.

[0013] The imaging board 21 and the lens holder 18 may be fixed by other means, such as adhesive fixation. Alternatively, the imaging board 21 may be fixed to a plate member, and the imaging board 21 may be fixed to the lens holder 18 via the plate member. Alternatively, a sealing member may be disposed between the imaging board 21 and the lens holder 18 to prevent dust from adhering to the imaging element 20.

[0014] The desired scene can be captured by focusing light rays through the lens group held by the lens unit 4 onto the image sensor 20. The lens holder 18 has a female thread 18a molded into its inner circumferential surface. The lens holder 18 may be made of either a metal such as aluminum or a resin such as polycarbonate.

[0015] The lens unit 4 is attached to the lens holder 18 by threading a male thread portion 11a provided on the outer diameter of the lens unit 4 into a female thread portion 18a of the lens holder 18. By rotating the lens unit 4 relative to the lens holder 18, the lens unit 4 moves forward and backward in the optical axis OO direction relative to the lens holder 18. This makes it possible to change the position of the lens unit 4 in the optical axis OO direction relative to the imaging unit 3 fixed to the lens holder 18, thereby making it possible to adjust the focus.

[0016] Fig. 3(A) is an exploded perspective view of the lens unit 4 as seen from the subject side of the lens unit 4, and Fig. 3(B) is an exploded perspective view of the lens unit 4 as seen from the image side of the lens unit 4. Fig. 4(A) is a view of the decentering adjustment member as seen from the image side, and Fig. 4(B) is a view of the decentering adjustment member as seen from the subject side. Fig. 5 is a cross-sectional view of the lens unit 4. In Fig. 4, the thick dotted line represents the second lens 13, and the thin dotted line represents the first lens 12.

[0017] The lens unit 4 is composed of a lens barrel 11 , a first lens 12 , a second lens 13 , a group of other lenses 14 , an eccentricity adjusting member 15 , a press ring 16 , and an elastic member 17 .

[0018] The lens barrel 11 (lens holding frame) holds the first lens 12 and the other lens group 14. The lens barrel 11 is made of a metal such as aluminum or a resin such as polycarbonate. The lens barrel 11 has a male thread portion 11a, a crimping claw portion 11b, a contact portion 11c, and a female thread portion 11d. The male thread portion 11a screws into the female thread portion 18a of the lens holder 18. The crimping claw portion 11b secures the first lens 12. Multiple crimping claw portions 11b are arranged at equal intervals in the circumferential direction. The contact portion 11c is a portion that the eccentricity adjustment member 15 contacts, and multiple contact portions 11c are arranged alternately with the crimping claw portions 11b in the circumferential direction. The female thread portion 11d screws into a male thread 16a provided on the outer circumferential surface of the press ring 16.

[0019] First lens 12 is a reference lens that serves as a reference when adjusting decentering, and is inserted through an opening provided on the image side of lens barrel 11. One end of first lens 12 in the optical axis direction is fixed by crimping claw portion 11b (crimping portion). Specifically, first lens 12 is fixed to lens barrel 11 by thermal crimping. The other end of first lens 12 in the optical axis direction is fixed to first mating portion 15a of eccentricity adjustment member 15. Specifically, first lens 12 is mated or press-fit into first mating portion 15a of eccentricity adjustment member 15.

[0020] The second lens 13 is a lens for decentering adjustment, which is adjusted for decentering relative to the first lens 12 by decentering its position in a direction perpendicular to the optical axis, and is fixed to an eccentricity adjustment member 15. Specifically, the second lens 13 is mated or press-fitted into the eccentricity adjustment member 15.

[0021] The other lens group 14 is inserted through an opening provided on the subject side of the lens barrel 11 and is fixed in place by a retaining ring (not shown).

[0022] The decentering adjustment member 15 is a member for decentering the second lens 13 with respect to the first lens 12. When viewed from the optical axis direction, the decentering adjustment member 15 positions the second lens 13 and the first lens 12 so that their central positions do not overlap.

[0023] The decentering adjustment member 15 has a first mating portion 15a, a notch 15b, a second mating portion 15c, and a third mating portion 15d. The first mating portion 15a has a peripheral surface extending in the optical axis direction, except for the portion of the notch 15b. The first lens 12 is partially mated or press-fitted into the first mating portion 15a.

[0024] The notch 15b engages with the lens barrel 11 that holds the first lens 12. The crimping claws 11b that secure the first lens 12 are inserted into the notch 15b. The second and third mating portions 15c and 15d are portions for decentering the second lens 13 in a direction perpendicular to the optical axis. The second and third mating portions 15c and 15d have different amounts and directions of decentration. A plurality of the second and third mating portions 15c and 15d are provided along the circumferential direction of the first and second lenses 12 and 13. At least one of the plurality of second mating portions 15c has a different radial thickness than the other second mating portions 15c. At least one of the plurality of third mating portions 15d has a different radial thickness than the other third mating portions 15d.

[0025] Furthermore, decentering adjustment member 15 is inserted from the opening on the image side of lens barrel 11. Decentering adjustment member 15 is inserted into lens barrel 11 with first mating portion 15a and first lens 12 partially mated or press-fitted. Then, decentering adjustment member 15 is inserted and assembled to a position where it abuts against abutting portion 11c provided on lens barrel 11.

[0026] In this way, the position of the eccentricity adjusting member 15 in the direction perpendicular to the optical axis relative to the first lens 12 is determined by engaging or press-fitting the eccentricity adjusting member 15 with the first lens 12 via the first engaging portion 15a.

[0027] Furthermore, the crimping claws 11b that secure the first lens 12 are inserted into the notches 15b of the decentering adjustment member 15. By inserting the crimping claws 11b into the notches 15b in this way, the position of the decentering adjustment member 15 in the rotational direction relative to the optical axis OO is also regulated. Furthermore, since the crimping claws 11b and the notches 15b are formed at positions that are equal intervals of 120°, it is possible to assemble the first lens 122 at three phases every 120° in the rotational direction relative to the optical axis OO. Note that the number of equal intervals is an example and is not limited to this.

[0028] Pressing ring 16 biases second lens 13 in the optical axis direction by pressing elastic member 17. Male thread 16a provided on the outer peripheral surface of pressing ring 16 is threadedly engaged with female thread portion 11d provided on the inner peripheral surface of lens barrel 11. Furthermore, pressing ring 16 presses eccentricity adjustment member 15 by abutting against it.

[0029] The elastic member 17 is disposed on the second lens 13. The elastic member 17 biases the second lens 13 in the optical axis direction.

[0030] Next, the details of the decentering adjustment member 15 will be described. As shown in FIG. 4A, the decentering adjustment member 15 is provided with second joint portions 15c whose centers O-15c are decentered by a distance y1 in the direction perpendicular to the optical axis (+Y direction) with respect to the center O-15a of the first joint portion 15a. The thicknesses of the three second joint portions 15c are varied to allow the centers O-15c to be decentered. Specifically, as shown in FIG. 4A, the upper two second joint portions 15c are thinner than the lower second joint portion 15c. As a result, the second lens 13, indicated by the thick dotted line, is decentered in the +Y direction.

[0031] As a result, the center of the second lens 13 is disposed at a position offset by y1 from the center of the first lens 12. As shown in Fig. 5, the center O-13 of the second lens 13 is eccentric by +y1 in the direction perpendicular to the optical axis relative to the center O-12 of the first lens 12. In other words, the center O-15c of the second fitting portion 15c in the orthogonal plane perpendicular to the optical axis of the second lens 13 is located at a position eccentric to the center O-15a of the first fitting portion 15a in the orthogonal plane.

[0032] In addition, a third joint portion 15d is provided whose center O-15d is eccentric by a distance y2 in the direction perpendicular to the optical axis (-Y direction) from the center O-15a of the first joint portion 15a. By varying the thickness of the three third joint portions 15d, the centers O-15c are made eccentric.

[0033] Specifically, as shown in Figure 4(B), the two upper third joint portions 15d are thicker than the lower third joint portion 15d. As a result, the second lens 13, indicated by the thick dotted line, is decentered in the -Y direction. Note that the amount of decentering y1 in Figure 4(A) is different from the amount of decentering y2 in Figure 4(B). In other words, even when the decentering adjustment member 15 is rotated, the position of the second lens 13 does not match.

[0034] As a result, the center of the second lens 13 is disposed at a position shifted by y2 from the center of the first lens 12. In other words, the center O-13 of the second lens 13 is decentered by −y2 with respect to the center O-12 of the first lens 12 in the direction perpendicular to the optical axis.

[0035] Moreover, the second engagement portion 15c is provided on a first surface in the optical axis direction of the eccentricity adjustment member 15. The third engagement portion 15d is provided on a second surface, which is the surface opposite to the first surface in the optical axis direction of the eccentricity adjustment member 15. Note that the eccentricity direction and eccentricity amount of the second engagement portion 15c and the third engagement portion 15d are merely examples and are not limited thereto.

[0036] Moreover, the decentering direction can be changed by rotating the decentering adjustment member 15 around the optical axis OO relative to the lens barrel 11 and changing the assembly position.

[0037] Furthermore, the shape of the decentering adjustment member 15 is the same except for the second mating portion 15c and the third mating portion 15d. Therefore, the decentering adjustment member 15 can be press-fitted into the first lens 12 without mating by selecting either the second mating portion 15c or the third mating portion 15d.

[0038] After the first lens 12 is fixed to the decentering adjustment member 15, the second lens 13 is engaged or press-fitted into the second engagement portion 15c or the third engagement portion 15d provided on the decentering adjustment member 15. This restricts the position of the second lens 13 in the direction perpendicular to the optical axis.

[0039] Next, elastic member 17 is placed on second lens 13, and female thread portion 11d provided on the inner peripheral surface of lens barrel 11 and male thread 16a provided on the outer peripheral surface of retaining ring 16 are threadedly engaged, causing retaining ring 16 to press elastic member 17. As a result, elastic member 17 biases second lens 13 in the optical axis direction.

[0040] Furthermore, the pressing ring 16 presses the eccentricity adjustment member 15 by abutting against it. By configuring the pressing ring 16 with an internal thread in this way, the eccentricity adjustment member 15 and the pressing ring 16 overlap in the direction perpendicular to the optical axis OO. This makes it possible to prevent the diameter from becoming too large.

[0041] Next, the procedure for adjusting the decentering of the second lens 13 will be described. A lens other than the second lens 13 is inserted into the lens barrel 11. At this time, due to manufacturing variations such as component variations and assembly variations, each lens is misaligned in the direction perpendicular to the optical axis relative to the reference lens (first lens 12). In this state, the amount of misalignment of each lens in the direction perpendicular to the optical axis is measured using an eccentricity measuring device. Based on the measurement results, the position (direction, amount) of the second lens 13 in the direction perpendicular to the optical axis that improves the central resolution performance or the peripheral resolution performance is calculated. Based on the calculation results, the combination of the decentering amount and decentering direction selectable by the decentering adjustment member 15 that is closest to the calculated value is selected, and the lens is assembled. In this embodiment, based on the calculation results, it is selected whether the second lens 13 should be mated with the second mating portion 15c or the third mating portion 15d provided on the decentering adjustment member 15, and then the lens is assembled.

[0042] As described above, this embodiment includes a first lens 12, a second lens 13, and an eccentricity adjustment member 15 having a first fitting portion 15a into which the first lens 12 can be fitted and a second fitting portion 15c into which the second lens 13 can be fitted. Furthermore, the center of the second fitting portion 15c in a plane perpendicular to the optical axis of the second lens 13 is positioned eccentrically relative to the center of the first fitting portion 15a in the plane perpendicular to the optical axis of the second lens 13. In this way, since the second lens 13 is already eccentric relative to the first lens 12 when fixed to the eccentricity adjustment member, there is no need to separately fix the lens position using an adhesive or the like after eccentricity adjustment. This makes it possible to provide a lens module that can suppress lens misalignment after adjustment. [Explanation of symbols]

[0043] 1 camera module 2 Lens Module 3 Imaging unit 4 Lens unit 11 Lens barrel 11a Male thread 11b Crimping claw 11c Contact part 12 First Lens 13 Second Lens 14 Other lenses 15 Eccentricity adjustment member 15a First joint 15b Notch 15c Second joint 15d Third Joint 16 Retaining ring 17 Elastic member 18 Lens holder 19 screws 20 Image sensor 21 Imaging board

Claims

1. The first lens, A second lens, a lens holding frame that holds the first lens; an adjustment member that holds the second lens and adjusts the position of the second lens perpendicular to the optical axis direction, The adjustment member is a first fitting portion into which the first lens can be fitted and a second fitting portion into which the second lens can be fitted, A lens module characterized in that the center of the second fitting portion in an orthogonal plane perpendicular to the optical axis of the second lens is located at a position eccentric to the center of the first fitting portion in the orthogonal plane.

2. 2. The lens module according to claim 1, wherein the second fitting portion is provided in a plurality of positions along a circumferential direction, and at least one of the plurality of second fitting portions has a thickness in a radial direction different from that of the other second fitting portions.

3. the adjustment member includes a third fitting portion into which the second lens can be fitted, The lens module according to claim 1 , wherein the first mating portion is located between the second mating portion and the third mating portion.

4. The lens module according to claim 3, characterized in that the second engagement portion is provided on a first surface of the adjustment member in the optical axis direction, and the third engagement portion is provided on a second surface that is the surface opposite the first surface in the optical axis direction.

5. 4. The lens module according to claim 3, wherein the second lens is fitted into either the second fitting portion or the third fitting portion.

6. The lens module according to claim 3 , wherein the second engagement portion and the third engagement portion have different amounts of eccentricity with respect to the center of the first engagement portion.

7. The lens module according to claim 3, wherein the adjustment member is capable of changing the eccentricity direction of the second mating portion or the third mating portion relative to the center of the first mating portion by rotating it around the optical axis.

8. the adjustment member has a notch, The lens module according to claim 1 , wherein the notch engages with the lens holding frame.

9. 9. The lens module according to claim 8, wherein the first lens is fixed to the lens holding frame by thermal caulking, and a caulked portion is inserted into the notch.

10. 2. The lens module according to claim 1, wherein the first lens is a reference lens, and the second lens is a lens for adjusting decentering.

11. a press ring having a threaded portion formed on an outer peripheral surface thereof, and a threaded portion formed on an inner peripheral surface of the lens holding frame; 2. The lens module according to claim 1, wherein an inner peripheral surface of the lens holding frame and an outer peripheral surface of the pressing ring are screwed together to press the adjustment member in the optical axis direction.

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