JP2003084184A - Lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the miniaturization of the whole unit by shortening a length in an optical axis direction. SOLUTION: A diaphragm 22 is formed like a thin plate, and the diaphragm 22 is fixed in the fitting recess 25 of a lens frame 21 while bringing the diaphragm 22 in tight contact with a lens 23. Then, as compared with the conventional case where the diaphragm of a prescribed thickness is integrally formed with the lens frame, the thickness of the diaphragm 22 is satisfactorily reduced, then, the length in the optical axis 6 direction is shortened and the miniaturization of the whole unit is attained. In this case, a flange type holding part 24 for holding the outer peripheral part of the lens 23 is formed on the inner peripheral surface of the lens frame 21, then, the whole unit is prevented from becoming large in size even if the thickness of the holding part 24 is made larger, and the lens 23 is surely and firmly fixed by the holding part 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens unit used in a camera.

[0002]

2. Description of the Related Art For example, in a small camera incorporated in a mobile phone, a holder member 2 is provided on a substrate 1 and an image pickup unit 3 is provided in the holder member 2 as shown in FIG.
And the crystal filter 4 are arranged, and the lens unit 5 is attached to the holder member 2, so that the lens unit 5, the crystal filter 4, and the imaging unit 3 are arranged on the optical axis 6 in order from the subject side. There is.

In this case, as shown in FIG. 3, the image pickup unit 3 is provided in a fixed base 7 provided on the substrate 1 located in the holder member 2 and in a recess 7a of the fixed base 7. A solid-state image sensor 8 such as a CCD, and a cover glass 9 provided on the fixed base 7 to cover the solid-state image sensor 8, and the solid-state image sensor according to the image of the subject captured by the lens unit 5. 8 is configured to output an electrical signal. The crystal filter 4 is an optical low-pass filter, and is provided in the holder member 2 in a state corresponding to the subject side (upper side in FIG. 3) of the imaging unit 3.

The lens unit 5, as shown in FIG.
A lens frame 10 attached to the holder member 2 is provided, and a diaphragm 11 and a lens 12 are sequentially provided in the lens frame 10 from the subject side (upper side in the figure). In this case, the lens frame 10 is formed in a cylindrical shape and has a structure in which a frame-shaped diaphragm 11 is integrally formed at the tip (upper end in the figure), and the male screw 10a formed on the cylindrical outer peripheral surface is attached to the holder member. Two
It is attached to the holder member 2 by being screwed into the female screw 2a formed on the.

The diaphragm 11 is, as shown in FIG. 3, a lens frame 10.
Is integrally formed with a predetermined wall thickness t (for example, about the same thickness as the lens thickness of the lens 12), and a through hole 11a is formed in the center thereof with the optical axis 6 as the center. . In this case, the through hole 11a is formed in a tapered shape with a large diameter on the upper side (subject side) and a small diameter on the lower side (image side). The lens 12 is a meniscus convex lens having a concave surface facing the subject side (the upper surface side in FIG. 3), and the lower surface of the outer periphery of the lens 12 is fixed by the welding portion 13 by heat welding in a state of being arranged in the upper portion of the lens frame 10. Has been done.

[0006]

However, in the lens unit 5 of such a small camera, since the diaphragm 11 is integrally formed with the lens frame 10, a predetermined wall thickness t is required to mold the diaphragm 11. This is necessary, and there is a problem that the entire unit becomes longer in the optical axis 6 direction due to the thickness t, and the entire unit becomes larger accordingly.

An object of the present invention is to reduce the length in the optical axis direction to reduce the size of the entire unit.

[0008]

According to the present invention, in a lens unit having an aperture on the object side of a lens fixed to a lens frame, the aperture is formed in a thin plate shape, and the aperture is in close contact with the lens. It is characterized by being fixed to the frame. According to this invention, the diaphragm is formed in a thin plate shape, and the diaphragm is fixed to the lens frame while being in close contact with the lens, so that the diaphragm is integrally formed with a predetermined thickness in the lens frame as in the conventional example. Compared with the case, the thickness of the diaphragm can be made sufficiently thin, so that the length in the optical axis direction can be shortened, and the size of the entire unit can be reduced.

In this case, the diaphragm is formed to be larger than the outer shape of the lens and is fixed to the lens frame while being positioned, so that the mirror can be seen from the outer peripheral portion of the diaphragm. It is possible to prevent unnecessary external light from entering the inside of the frame. Further, as described in claim 3, a collar-shaped holding portion that holds the image surface side in the outer peripheral portion of the lens is formed in the lens frame, so that the holding portion is made thicker. However, the size of the entire unit does not increase, and the lens can be securely and firmly fixed by the holding portion.

[First Embodiment]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the lens unit of the present invention is applied to a compact camera will be described below with reference to FIG. The same parts as those of the conventional example shown in FIG. In this small camera, the lens unit 20 has a structure different from that of the conventional example, and other than that, the structure is almost the same as that of the conventional example. That is,
The lens unit 20 has a structure in which a diaphragm 22 and a lens 23 are sequentially provided from a subject side (upper side in FIG. 1) in a lens frame 21.

In this case, the lens frame 21 is formed in a cylindrical shape as shown in FIG. 1, and a collar-shaped holding portion 24 for holding the lens 23 is formed in the intermediate portion of the inner peripheral surface thereof. ing. The upper surface (subject side) of the inner peripheral surface of the holding portion 24 is the lens 2 so that the angle of view of the diaphragm 22 is not limited.
It has a larger diameter (smaller diameter) than the lens function portion 3 and a taper shape in which the lower side is larger than this diameter (larger diameter). Further, a mounting recess 25 for mounting the diaphragm 22 and the lens 23 is formed on the upper portion of the holding portion 24 in the lens frame 21. In addition, this lens frame 21
Is a male screw 21 formed on the outer peripheral surface thereof, as in the conventional example.
It is attached to the holder member 2 by screwing a into a female screw 2a formed on the holder member 2.

Further, the lens 23 is a meniscus convex lens with a concave surface facing the subject side (upper surface side in the figure) as in the conventional example, and its outer peripheral portion has the same lens thickness as the central portion,
It is formed in a flat shape thinner than that. This lens 2
3 is inserted into the mounting recess 25 from above, and the flat lower surface of the outer peripheral portion thereof is fixed to the holding recess 24 in the mounting recess 25 by an adhesive or the like. In this case, the lens 23
The optical path length from the central portion to the central portion of the solid-state image pickup device 8 of the image pickup unit 3 is set to the same length as the conventional example.

The diaphragm 22 is, as shown in FIG. 1, a lens frame 21.
It is a component having a different structure from that of the lens 23, and is formed in a thin plate shape that is sufficiently thin relative to the lens thickness of the lens 23, and its outer shape is formed to have substantially the same size as the lens 23, and a circular through hole 22a is formed in the center thereof. The upper and lower sides have the same diameter. The diaphragm 22 is inserted into the mounting recess 25 from above so as to be in close contact with the upper surface of the lens 23, and the upper surface of the diaphragm 22 has the upper surface of the lens frame 21.
The mounting recess 25 while being substantially flush with the upper end surface of the
It is fixed inside with adhesive.

In the lens unit 20 as described above, the diaphragm 22 is formed in a thin plate shape that is sufficiently thin relative to the lens thickness of the lens 23, and the diaphragm 22 is attached to the lens 23 in a mounting recess 25 of the lens frame 21. Since the diaphragm 22 is fixed inside, the thickness of the diaphragm 22 can be made sufficiently thin as compared with the case where the diaphragm 11 is integrally formed with the lens frame 10 with a predetermined thickness t as in the conventional example. The length in the six directions can be shortened, and the size of the entire unit can be reduced.

In this case, the lens 23 is provided on the inner peripheral surface of the lens frame 21.
Collar-shaped holding portion 24 that holds the lower surface (image surface side) of the outer peripheral portion of the
Therefore, even if the thickness of the holding portion 24 is increased,
The whole unit does not increase in size, and the lens 24 is held by the holding unit 24.
3 can be securely and firmly fixed. In particular, the inner peripheral surface of the holding portion 24 is such that the upper side (subject side) is the lens 23.
The diameter of the diaphragm is smaller than that of the lens function portion of the above, and the lower side is formed in a taper shape with a large diameter.
The image of the subject can be captured well without restricting the angle of view by 2.

[Second Embodiment] Next, referring to FIG.
A second embodiment of the lens unit of the present invention will be described. In this case, the same parts as those of the first embodiment shown in FIG. The lens unit 30 has a structure in which a diaphragm 31 is formed to be larger than the outer shape of the lens 23, and a lens mounting recess 32 and a diaphragm mounting recess 33 are formed in the lens frame 21. The rest is the same as in the first embodiment. It is structured.

That is, as in the first embodiment, the diaphragm 31 is formed in a thin plate shape that is sufficiently thinner than the lens thickness of the lens 23, its outer shape is formed larger than that of the lens 23, and its center is circular. The through holes 31a having a shape are formed with the same diameter in the vertical direction. Like the first embodiment, the lens frame 21 has a holding portion 24 formed on its inner peripheral surface,
A lens mounting recess 32 for mounting the lens 23 is formed in the lens frame 21 located above the holding unit 24 with a depth substantially the same as the thickness of the outer peripheral portion of the lens 23. A diaphragm mounting recess 33 for mounting and positioning the diaphragm 31 is formed in the upper portion so as to be larger than the outer shape of the lens mounting recess 32 and to have a depth substantially the same as the thickness of the diaphragm 31.

In such a lens unit 30, the first
In addition to the same effects as the embodiment, the diaphragm 31 is formed to be larger than the outer shape of the lens 23, and the diaphragm 31 is positioned in the diaphragm mounting recess 33 formed in the lens frame 21 and fixed with an adhesive or the like. Therefore, it is possible to prevent unnecessary external light from entering the inside of the lens frame 21 from the outer peripheral portion of the diaphragm 31, which allows the image of the subject to be captured well and a clear image to be obtained. .

[0019]

As described above, according to the present invention, the diaphragm is formed in the shape of a thin plate, and the diaphragm is fixed to the lens frame while being in close contact with the lens. Compared with the case where the frame is integrally formed with a predetermined wall thickness, the thickness of the diaphragm can be made sufficiently thin, which allows the length in the optical axis direction to be shortened and the size of the entire unit can be reduced. be able to.

In this case, the aperture is formed larger than the outer shape of the lens and fixed in a state of being positioned in the lens frame to prevent unwanted external light from entering the inside of the lens frame from the outer peripheral portion of the aperture. This makes it possible to capture a clear image of the subject. Further, by forming the flange-shaped holding portion for holding the outer peripheral portion on the image side of the lens in the lens frame, even if the holding portion is formed thick, the entire unit does not increase in size and The lens can be securely and firmly fixed.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a main part of a first embodiment in which a lens unit of the present invention is applied to a small camera.

FIG. 2 is an enlarged cross-sectional view of an essential part showing a second embodiment of the lens unit of the present invention.

FIG. 3 is an enlarged cross-sectional view of a main part in which a conventional lens unit is applied to a small camera.

[Explanation of symbols]

20, 30 lens unit 21 mirror frame 22, 31 aperture 23 lenses 24 Holder 25 Mounting recess 32 Lens mounting recess 33 Aperture mounting recess

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 9/02 G03B 9/02 Z H04N 5/225 H04N 5/225 D 5/335 5/335 V

Claims (3)

[Claims] 1. A lens unit having an aperture on the object side of a lens fixed to a lens frame, wherein the aperture is formed in a thin plate shape and is fixed to the lens frame in a state of being in close contact with the lens. Characteristic lens unit. 2. The lens unit according to claim 1, wherein the diaphragm is formed larger than the outer shape of the lens, and is fixed to the lens frame while being positioned. 3. The lens unit according to claim 1, wherein the lens frame is provided with a collar-shaped holding portion that holds the image surface side of the outer peripheral portion of the lens.