WO2011021450A1 - Lens unit and capsule endoscope with same - Google Patents

Abstract

A lens unit configured in such a manner that molded lenses which, despite being small-diameter molded lenses, can be inserted and mounted to a lens frame without being obstructed by burrs and can achieve good accuracy in the optical axis direction without adjustment at the time of the mounting. A lens unit provided with molded lenses which comprise flange sections (6), and also with at least one lens frame (4). At least one of the molded lenses has burrs (7) which extend parallel to the optical axis and are located on the flange section of the molded lens in a portion closest to the inner peripheral surface of the lens frame. In order to prevent the interference between the burrs, which extend parallel to the optical axis, and the lens frame or another molded lens which is adjacent to the burrs, a step (6') is formed on the flange section in the portion in which the burrs, which extend parallel to the optical axis, are located.

Description

Lens unit and capsule endoscope provided with the same

The present invention relates to a lens unit incorporating a molded lens, and can be used, for example, in a capsule endoscope apparatus used in the medical field.

In recent years, capsule endoscopes have come to be used in the medical field for diagnosis of places where conventional endoscopes that insert conventional tubes are difficult to reach, such as the small intestine.

Capsule endoscopes are easy to swallow from the mouth, and it is desirable to make them as small as possible so that they can move safely through the body. Desirable for popularization.

Therefore, a plastic lens by injection molding is used for the lens unit of the capsule endoscope. By the way, generation | occurrence | production of a burr | flash is unavoidable on the structure of a shaping | molding lens, and the presence of a burr | flash has a big influence on the assembly process of a lens unit and the lens precision after an assembly. Therefore, several methods have been proposed to avoid the influence of burrs in a lens unit using a molded lens.

For example, Patent Document 1 discloses a configuration in which a concave portion for accommodating burrs of two adjacent lenses is provided in one lens abutting portion, and both burrs are accommodated in the concave portion.

In Patent Document 2, a ring-shaped relief groove is formed at the corner of one lens on the contact surface between the lenses, and a burr generated during resin molding enters the corner portion in the relief groove. It is shown.

Further, Patent Document 3 shows a configuration in which a tapered portion is provided in the lens housing groove of the lens frame so that the burr of the lens does not cover the lens housing groove of the lens frame.

JP 2003-195010 A JP 2005-258329 A JP 2005-309000 A

However, these prior examples have the following problems.
In Patent Documents 1 and 2, the lens flange portion is formed with a recess and relief groove to prevent burrs, so when a plurality of lenses are combined, this recess or relief groove exists in the middle of the lens abutment surface. As a result, the accuracy of the abutting surface is lowered. In addition, the length and area of the abutting surface are reduced by dividing the abutting surface by the recess and the escape groove. Therefore, when assembling the lens unit, adjustment in the optical axis direction is required, and in some cases, sufficient accuracy cannot be obtained due to a shortage of the abutting surface.

Patent Document 3 shows an example of a molded lens in which burrs are formed in the direction perpendicular to the optical axis only on the exit end side. In the case of a molded lens in which burrs are formed in the direction perpendicular to the optical axis only on the exit end side, when assembling a lens unit using these molded lenses, a recess or relief is provided in the middle of the lens abutment surface. Since there is no groove, the accuracy of the abutting surface does not drop and assembly can be performed with high accuracy.

However, as shown in Patent Document 3, if the lens is used for an optical unit of a mobile phone, the lens diameter is at least about 5 mm, so that the burr can be molded only on one side of the molded lens. is there.

However, since the lens unit of the present invention is intended for use in a capsule endoscope, the diameter of the lens is about 2 to 3 mm. In the case of a molded lens having a lens diameter of 2 to 3 mm, it is difficult to mold with high accuracy unless a mold having three or more divisions that generate burrs on both the entrance surface side and the exit surface side of the lens is used.

That is, as shown in FIG. 8 (a), when a plastic lens is molded using a two-part mold as in Patent Document 3, the contact area is large when the mold is released, so the resistance is large and the movable side mold member is used. The shape of the contacting surface is easily deformed, and the distortion and internal stress of the molded lens increase. Therefore, in the case of a molded lens having a lens diameter of 2 to 3 mm that is assumed to be used in the present invention, it is basically unsuitable to use a two-divided mold as shown in Patent Document 3. On the other hand, as shown in FIG. 8B, when a plastic lens is molded using a three-part mold using an insert, the contact area when releasing is small and the resistance is small. Accordingly, the surface of the molded lens is not deformed, and distortion and internal stress are extremely small. Therefore, the molded lens used in the present invention needs to be molded using a mold having three or more divisions.

Although there is a method for preventing deformation by reducing the resistance between the mold and the molded product by using a release agent or the like to improve the releasability, the lens unit of the present invention is used in the medical field. Since it is assumed to be used for a capsule endoscope apparatus, a release agent cannot be easily used.

For the reasons described above, since the molded lens used in the present invention uses a mold of three or more parts, the occurrence of burrs at a plurality of locations is inevitable. Therefore, if the position of the burr is not devised, the burr must grow larger as the mold wears, so the burr gets in the way when fitting with the lens frame or hitting the lens flange parts. Therefore, there is a problem that the accuracy in the axial direction is deteriorated or the lens diameter is increased in order to avoid burrs.

The size of the burr is determined by the assembly accuracy of the mold, but is usually about 0.1 mm to 0.15 mm regardless of the size of the molding. While the mold is new, the burrs may be smaller, but the burrs become larger as the mold wears. Therefore, it is necessary to consider in advance so that the burrs having the above-mentioned size can be dealt with. Furthermore, in the case of a molded lens, as the lens becomes smaller, the assembly accuracy is more likely to be affected by burrs, so how to release the burrs is an important issue.

The present invention has been made in view of the above-described circumstances, and by devising the position of the burr of the molded lens, when the molded lens is inserted into the lens frame and incorporated into the lens frame, the burr is not formed. It is an object of the present invention to provide a lens unit that does not get in the way and that does not need to be adjusted in the optical axis direction during installation.

In order to solve the above problems, a lens unit according to the present invention is a lens unit including a plurality of molded lenses having a flange portion and at least one lens frame, wherein at least one of the molded lenses is the molded lens. A lens frame having a burr extending in a direction parallel to the optical axis in a portion of the flange portion closest to the inner peripheral surface of the lens frame, and adjacent to the burr extending in a direction parallel to the optical axis of the molded lens. A burr extending in a direction parallel to the optical axis in the flange portion of the molded lens is provided so that the molded lens different from the molded lens and a burr extending in a direction parallel to the optical axis of the molded lens do not interfere with each other. A step is provided in the flange portion of the portion to be provided.

The lens unit according to the present invention is a lens unit comprising a plurality of molded lenses having a flange portion and at least one lens frame, wherein at least one of the molded lenses is incident on the flange portion of the molded lens. The lens frame or the molding having a burr extending in a direction parallel to the optical axis at a portion closest to the inner peripheral surface of the lens frame on a side end surface, and adjacent to the burr extending in a direction parallel to the optical axis of the molded lens. The molded lens separate from the lens and a burr extending in the direction parallel to the optical axis of the molded lens extend in a direction parallel to the optical axis on the incident side end surface of the flange portion of the molded lens. A step is provided in the flange portion of the portion having the burr, and the portion of the outer peripheral surface of the flange portion of the molded lens that is closest to the exit side end surface is opposed to the optical axis. The lens frame has a burr extending in a vertical direction, and the lens frame has an inner peripheral surface of the lens frame so that the lens frame and a burr extending in a direction perpendicular to the optical axis of the molded lens do not interfere with each other. A step is provided in a portion near the burr extending in a direction perpendicular to the optical axis of the molded lens.

In the lens unit according to the present invention, it is preferable that the plurality of molded lenses have a larger diameter on the exit side of the molded lens than on the incident side.

In the lens unit according to the present invention, it is preferable that each of the plurality of molded lenses has a cylindrical outer shape of the flange portion and satisfies the following conditional expression (1).
1 <φL / tL <6.17 (1)
Here, tL is the total length (mm) of the molded lens, and φL is the outer diameter (mm) of the molded lens.

In the lens unit according to the present invention, it is preferable that the lens unit is an imaging lens and the angle of view is 130 degrees or more.

Moreover, in the lens unit according to the present invention, the lens unit further includes an aperture stop, and among the plurality of molded lenses, a molded lens that is closer to the entrance side than the brightness stop and located closest to the entrance side. Has a burr extending in a direction parallel to the optical axis at a portion closest to the inner peripheral surface of the lens frame on the incident side end surface of the flange portion of the molded lens, and extends in a direction parallel to the optical axis of the molded lens. A step is provided on the flange portion of the portion having a burr extending in a direction parallel to the optical axis on the incident side end surface of the molded lens so that the burr does not block incident light that can pass through the aperture stop. preferable.

Further, in the lens unit according to the present invention, the lens unit further includes an aperture stop, and among the plurality of molded lenses, a molded lens that is located on the exit side and closest to the entrance side of the brightness stop. Has a burr extending in a direction parallel to the optical axis at a portion closest to the inner peripheral surface of the lens frame on the incident side end surface of the flange portion of the molded lens, and extends in a direction parallel to the optical axis of the molded lens. A step is provided on the flange portion of the portion having a burr extending in a direction parallel to the optical axis on the incident side end surface of the molded lens so that the burr does not block incident light that can pass through the aperture stop. preferable.

Further, a capsule endoscope including the lens unit according to the present invention includes any one of the lens units according to the present invention.

According to the lens unit of the present invention, by devising the position of the burr of the molded lens, when the molded lens is inserted into the lens frame and assembled even though it is a small-diameter molded lens, the burr does not get in the way and It is possible to provide a lens unit that is favorable without adjusting the accuracy of the direction.

It is sectional drawing of Example 1 of the lens unit which concerns on this invention. It is the A section enlarged view of FIG. It is sectional drawing which shows the structure of the metal mold | die used for shaping | molding of the lens of an intermediate part among the three lenses used for the lens unit shown in FIG. It is sectional drawing of Example 2 of the lens unit which concerns on this invention. It is sectional drawing of Example 3 of the lens unit which concerns on this invention. It is sectional drawing of Example 4 of the lens unit which concerns on this invention. It is sectional drawing which shows an example of the capsule endoscope provided with the lens unit which concerns on this invention. It is explanatory drawing which shows the shaping | molding process of a plastic lens, (a) showed the example which uses a two-part type | mold, (b) showed the example of the three-part type | mold using an insert It is. The example of the shaping | molding lens used by this invention is shown, (a) shows the example when exceeding the upper limit of conditional expression (1), (b) shows the example when it falls below a lower limit. It is squeezed.

Prior to the description of the embodiments, the function and effect of the lens unit according to the present invention will be described.
The lens unit according to the present invention includes a plurality of molded lenses having flange portions and at least one lens frame. At least one of the molded lenses has a burr extending in a direction parallel to the optical axis at a position closest to the inner peripheral surface of the lens frame in the flange portion of the molded lens. Then, the molded lens adjacent to the burr extending in the direction parallel to the optical axis of the molded lens and the molded lens different from the lens frame or the molded lens and the burr extending in the direction parallel to the optical axis of the molded lens do not interfere with each other. A step is provided in the flange portion of the flange portion having a burr extending in a direction parallel to the optical axis.

A burr extending in a direction parallel to the optical axis is formed in a portion of the flange portion of the molded lens closest to the inner peripheral surface of the lens frame, and the flange portion is prevented from interfering with the burr and the lens frame or the adjacent molded lens. Providing a step to escape the burr prevents the burr and the lens frame or the adjacent molded lens from interfering when the lens unit is assembled. Further, when the burr is formed in a direction parallel to the optical axis, the diameter of the lens frame can be reduced.

The lens unit according to the present invention includes a plurality of molded lenses having flange portions and at least one lens frame. At least one of the molded lenses has a burr extending in a direction parallel to the optical axis at a position closest to the inner peripheral surface of the lens frame on the incident side end surface of the flange portion of the molded lens. Then, the molded lens is arranged so that the molded frame different from the lens frame or the molded lens adjacent to the burr extending in the direction parallel to the optical axis of the molded lens does not interfere with the burr extending in the direction parallel to the optical axis of the molded lens. A step is provided in the flange portion of the portion having a burr extending in the direction parallel to the optical axis on the incident side end surface of the flange portion.
In addition, a burr extending in a direction perpendicular to the optical axis is provided at a portion of the outer peripheral surface of the flange portion of the molded lens that is closest to the end surface on the emission side. The lens frame extends in a direction perpendicular to the optical axis of the molded lens on the inner peripheral surface of the lens frame so that the lens frame and a burr extending in a direction perpendicular to the optical axis of the molded lens do not interfere with each other. There is a step in the area close to the burr.

When the molded lens has a burr extending in the direction parallel to the optical axis on the incident side end face and a burr extending in the direction perpendicular to the optical axis on the exit side end face, a small diameter molded lens can be molded with high accuracy. If the direction of the burr is made different between the incident side and the exit side, and a step is provided on the flange portion and the lens frame to escape the burr so that it does not interfere, The lens unit does not interfere with each other and does not interfere with the lens frame and the burr. And, since both the incident side end surface and the exit side end surface of the molded lens have no recess such as a recess or a relief groove in the flange portion, a smooth flat surface is formed with high precision, and when two lenses are abutted, The optical axes of the two lenses are exactly matched without any special adjustment.

Further, in the lens unit according to the present invention, it is preferable that the plurality of molded lenses have a larger diameter on the exit side of the molded lens than on the incident side.

The molded lens has burrs extending in the direction parallel to the optical axis on the incident side end face, and burrs extending in the direction perpendicular to the optical axis on the exit side end face. The molded lens on the incident side with a small lens diameter is formed so that the burr on the exit side is perpendicular to the optical axis, and the area on the exit side is formed so that the burr is parallel to the optical axis. It can be made larger than the case. Therefore, when the two lenses are abutted, the optical axes of the two lenses are more accurately matched.

In the lens unit according to the present invention, preferably, the plurality of molded lenses have a cylindrical outer shape of the flange portion of each molded lens,
Each molded lens satisfies the following conditional expression (1).
1 <φL / tL <6.17 (1)
Here, tL is the total length (mm) of the molded lens, and φL is the outer diameter (mm) of the molded lens.

This conditional expression is required because the lens unit is intended for use in a capsule endoscope. When this conditional expression is satisfied, the lens unit has a size suitable for use in a capsule endoscope.

When exceeding the upper limit value of the conditional expression (1), the lens diameter becomes thin (thin and large aperture) as shown in FIG. Therefore, the surface shape undulations and distortions are greatly affected. In addition, because of the thin wall, the resin is not completely filled, and perfect molding may not be possible. FIG. 9A shows an example of φL = 2.1 and tL = 0.21 (φL / tL = 10).
If the lower limit of conditional expression (1) is not reached, the total length of the lens becomes longer as shown in FIG. 9B, and the resistance at the time of mold release also increases. Further, since the surface area of the lens side surface portion is increased, distortion and internal stress are increased. FIG. 9B shows an example of φL = 2.1 and tL = 4.2 (φL / tL = 0.5).

In addition, the lens unit according to the present invention is preferably an imaging lens and has an angle of view of 130 degrees or more. If comprised in this way, when it uses for a capsule endoscope, the visual field which can be satisfied can be ensured.

In addition, the lens unit according to the present invention is preferably further provided with an aperture stop. Of the plurality of molded lenses, the molded lens that is closer to the incident side than the aperture stop and located closest to the incident side is located at a position closest to the inner peripheral surface of the lens frame on the incident side end face of the flange portion of the molded lens. It has a burr extending in a direction parallel to the optical axis. Then, a flange having a burr extending in the direction parallel to the optical axis on the incident side end face of the molded lens so that the burr extending in the direction parallel to the optical axis of the molded lens does not block incident light that can pass through the aperture stop. There is a step to escape the burr.

With this configuration, incident light passing through the aperture stop is not blocked by burrs extending in a direction parallel to the optical axis of the incident side end face.

In addition, the lens unit according to the present invention is preferably further provided with an aperture stop. Of the plurality of molded lenses, the molded lens located on the exit side of the aperture stop and located closest to the incident side is located at a position closest to the inner peripheral surface of the lens frame on the incident side end face of the flange portion of the molded lens. It has a burr extending in a direction parallel to the optical axis. The flange portion of the part having a burr extending in the direction parallel to the optical axis on the incident side end face of the molded lens is so arranged that the burr extending in the direction parallel to the optical axis of the molded lens does not block incident light that can pass through the brightness stop. There is a step to escape the burr.

With this configuration, incident light passing through the aperture stop is not blocked by burrs extending in a direction parallel to the optical axis of the incident side end face.

Also, the capsule endoscope provided with the lens unit according to the present invention includes the lens unit described above. Although it is a lens unit constituted by a small-diameter molded lens, it becomes a capsule endoscope provided with a highly accurate lens unit.

Hereinafter, embodiments of the lens unit according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, the lens unit of Example 1 is incident with the first molded lens 1, the second molded lens 2, the third molded lens 3, and these molded lenses 1, 2, and 3. The lens frame 4 is housed in order from the side toward the emission side, and the brightness stop 5 is provided between the first molded lens 1 and the second molded lens 2.

First, the molded lens will be described.
Each of the first molded lens 1, the second molded lens 2, and the third molded lens 3 has a flange portion 6. In addition, the second molded lens 2 has a larger diameter than the first molded lens 1, and the third molded lens 3 has a larger diameter than the second molded lens 2. That is, the diameter of the molded lens on the exit side is larger than that of the molded lens on the incident side. In the present invention, a portion other than a portion where the lens function is exhibited in the molded lens is referred to as a flange portion, and the diameter of the molded lens is a size including the flange portion.

The first molded lens 1, the second molded lens 2 and the third molded lens 3 each have a parallel burr 7 extending in a direction parallel to the optical axis on the incident side end face. The parallel burr 7 is formed at a portion closest to the inner peripheral surface of the lens frame 4 on the incident side end face of the flange portion 6 of each molded lens 1, 2, 3. A step 6 ′ is provided in the flange portion 6 of the portion having the parallel burr 7 on the incident side end faces of the second molded lens 2 and the third molded lens 3, and the tip of the parallel burr 7 is the flange. It protrudes from the part 6.

Further, each of the first molded lens 1, the second molded lens 2 and the third molded lens 3 has a vertical burr 8 extending in the direction perpendicular to the optical axis on the exit side end face. The vertical burr 8 is formed at a portion of the outer peripheral surface of the flange portion 6 of each molded lens 1, 2, 3 closest to the exit side end surface.

Here, an example of a mold used for molding a molded lens having a parallel burr 7 and a vertical burr 8 will be described with reference to FIG.
FIG. 3 shows a mold used for molding the second molded lens 2 shown in FIG. 1. The first mold member 9 on the fixed side and the movable facing the first mold member 9 are shown. The second mold member 10 on the side and the third mold member 11 on the movable side located on the outer periphery of the second mold member 10 are combined.

And the parallel parting line part 12 in which the parallel direction burr | flash 7 will be formed in the joining location of the 2nd metal mold | die member 10 and the 3rd metal mold | die member 11 as a result is also 1st metal mold | die. At the joint portion between the member 9 and the third mold member 11, a vertical dividing line portion 13 in which the vertical burr 8 is formed as a result is provided. In the illustrated example, the dividing line parts 12 and 13 are shown large for convenience of explanation, but are actually very small. However, it is necessary to provide the dividing line portions 12 and 13 so that the parallel burr 7 and the vertical burr 8 are formed in a desired direction as a result.

Next, the lens frame 4 that houses the molded lenses 1, 2, 3 and the aperture stop 5 will be described.
As described above, since the diameter increases in the order of the first molded lens 1, the second molded lens 2, and the third molded lens 3, the diameter of the inner peripheral surface of the lens frame 4 is also stored in each of the molded lenses stored therein. It increases in order according to the diameter. At least a part of the outer periphery of the flange portion 6 of each molded lens 1, 2, 3 is fitted to the inner peripheral surface of the lens frame 4 so that the molded lenses 1, 2, 3 are held against the lens frame 4. It has become.

In the lens frame 4, a first step 14 is formed to avoid interference between the vertical burr 8 of the first molded lens 1 and the parallel burr 7 of the second molded lens 2. A second step 15 is formed to avoid interference between the vertical burr 8 of the second molded lens 2 and the parallel burr 7 of the third molded lens 3. Further, in order to avoid interference with the vertical burr 8 of the third molded lens 3, the lens frame 4 is shortened instead of being provided with a step. It should be noted that a step 16 may be provided at the rear end of the lens frame 4 as shown in FIGS.

Next, a method for incorporating the molded lenses 1, 2, 3 and the brightness stop 5 into the lens frame 4 will be described.
First, the first molded lens 1 is inserted into the lens frame 4 from the exit end side of the lens frame 4 with the incident side end face first, and the outer periphery of the flange portion 6 of the first molded lens 1 is placed on the lens frame 4. It is made to fit with the inner peripheral surface. Since the burr on the incident-side end face of the first molded lens 1 is a parallel burr 7 parallel to the optical axis, when the first molded lens 1 is inserted into the lens frame 4, The parallel burr 7 does not interfere. On the other hand, the burr on the exit side end face of the first molded lens 1 is a vertical burr 8 perpendicular to the optical axis and protrudes from the outer periphery of the flange portion 6 of the first molded lens 1. Since the first step 14 is formed, the vertical burr 8 does not interfere with the lens frame 4.

Next, the aperture stop 5 is inserted from the exit end side of the lens frame 4, the outer periphery of the aperture stop 5 is fitted to the inner peripheral surface of the lens frame 4, and the exit end surface of the first molded lens 1 is fitted. Push until it touches. Next, the second molded lens 2 is inserted into the lens frame 4 so that the incident side end face comes first from the exit end side of the lens frame 4, and the outer periphery of the flange portion 6 of the second molded lens 2 is placed on the lens frame 4. And the end surface on the incident side of the second molded lens 2 is brought into contact with the brightness stop 5. Since the burr on the incident-side end surface of the second molded lens 2 is a parallel burr 7 parallel to the optical axis, when the second molded lens 2 is inserted into the lens frame 4, The parallel burr 7 does not interfere. Further, since a step 6 ′ is provided in the flange portion 6 of the part having the parallel burr 7 on the incident side end face of the second molded lens 2, the parallel direction between the aperture stop 5 and the second molded lens 2 is provided. The burr 7 does not interfere. On the other hand, the burr on the exit side end face of the second molded lens 2 is a vertical burr 8 perpendicular to the optical axis and protrudes from the outer periphery of the flange portion 6 of the second molded lens 2. Since the second step 15 is formed, the vertical burr 8 does not interfere with the lens frame 4.

Next, the third molded lens 3 is inserted into the lens frame 4 with the incident side end face leading from the exit end side of the lens frame 4, and the outer periphery of the flange portion 6 of the third molded lens 3 is placed on the lens frame. 4, the incident side end surface of the third molded lens 3 is brought into contact with the emission side end surface of the second molded lens 2. Since the burr on the incident side end surface of the third molded lens 3 is a parallel burr 7 parallel to the optical axis, when the third molded lens 3 is inserted into the lens frame 4, The parallel burr 7 does not interfere. On the other hand, the burr on the exit side end surface of the third molded lens 3 is a vertical burr 8 perpendicular to the optical axis and protrudes from the outer periphery of the flange portion 6 of the third molded lens 3. Is shorter than the end surface on the exit side of the third molded lens 3, the vertical burr 8 does not interfere with the lens frame 4. Further, since the step 6 'is provided in the flange portion 6 of the portion having the parallel burr 7 on the incident side end face of the third molded lens 3, the vertical burr 8 and the third burr 8 of the second molded lens 2 are provided. The parallel burrs 7 of the molded lens 3 do not interfere with each other.

That is, as shown in FIG. 2 which is an enlarged view of a contact portion between the second molded lens 2 and the third molded lens 3, the second step 15 has the vertical burr 8 and the lens of the second molded lens 2. The frame 4 serves to prevent interference and the parallel burr 7 of the third molded lens 3 and the lens frame 4 serve to prevent interference. Further, the parallel burr 7 of the third molded lens 3 is not interfered with the flange 6 of the second molded lens 2 and the vertical burr 7 by providing the flange 6 with the step 6 'as described above. It has become. Since the size of the burr is usually 0.15 mm or less, each step may be set to a size that can avoid this size.

The contact surfaces of the molded lenses 1, 2, 3 are smooth surfaces, and there are no recesses such as a burr escape groove on the way, so the contact surfaces are divided on the way. Nor. Further, the burr on the exit side of the molded lens (for example, the second molded lens 2) positioned on the incident side, which has a small diameter with respect to the molded lens (for example, the third molded lens 3) positioned on the exit side, has a flange portion 6. Since the vertical burr 8 extending in the direction perpendicular to the optical axis is formed at a portion of the outer peripheral surface closest to the exit side end surface, the contact area with the molded lens (third molded lens 3) located on the exit side is set. Can be maximized. Therefore, the abutting accuracy of the molded lenses 1, 2, 3 and the brightness diaphragm 5 can be made extremely high by increasing the contact area. Adjustment of the optical axis, which was indispensable with conventional lens units, is no longer necessary. By simply inserting the molded lenses 1, 2, 3 and the aperture stop 5 into the lens frame 4 in order, special optical axis adjustments and the like can be performed. Even if it is not performed, the lens unit has practical accuracy.

Note that the parallel burr 7 formed on the incident side end surface of the first molded lens 1 does not block incident light that can pass through the aperture stop 5 at a site near the inner peripheral surface of the lens frame 4. Is formed. Further, the parallel burr 7 formed on the incident side end surface of the second molded lens 2 does not block incident light that can pass through the aperture stop 5 at a portion close to the inner peripheral surface of the lens frame 4. Is formed. Further, the angle of view of the lens unit of this embodiment is 130 ° C. or more.

As shown in FIG. 4, the lens unit of Example 2 stores the first molded lens 1, the second molded lens 2, and these molded lenses 1 and 2 in order from the incident side to the emission side. And a brightness diaphragm 5 provided between the first molded lens 1 and the second molded lens 2.

The first molded lens 1 and the second molded lens 2 each have a flange portion 6. Each of the first molded lens 1 and the second molded lens 2 has a parallel burr 7 extending in a direction parallel to the optical axis on the incident side end face. The parallel burr 7 is formed at a position closest to the inner peripheral surface of the lens frame 4 on the incident side end face of the flange portion 6 of each molded lens 1, 2. A step 6 ′ is provided in the flange portion 6 of the portion having the parallel burr 7 on the incident side end face of the second molded lens 2, so that the tip of the parallel burr 7 does not protrude beyond the flange portion 6. It has become. The second molded lens 2 has a larger diameter than the first molded lens 1. That is, the diameter of the molded lens on the exit side is larger than that of the molded lens on the incident side. In the present invention, a portion other than a portion where the lens function is exhibited in the molded lens is referred to as a flange portion, and the diameter of the molded lens is a size including the flange portion. In the figure, the incident side end surface of the first molded lens 1 is a flat surface, but the portion outside the range in which the incident light beam can pass through the aperture stop 5 is effectively the flange portion 6.

The first molded lens 1 and the second molded lens 2 each have a vertical burr 8 extending in the direction perpendicular to the optical axis on the exit side end surface. The vertical burrs 8 are formed on the outermost surfaces of the flange portions 6 of the respective molded lenses 1 and 2 at a portion closest to the exit side end surface.

Next, the lens frame 4 that houses the molded lenses 1 and 2 and the aperture stop 5 will be described.
As described above, since the diameter increases in the order of the first molded lens 1 and the second molded lens 2, the diameter of the inner peripheral surface of the lens frame 4 also increases in order according to the diameter of the molded lens to be accommodated. ing. At least a part of the outer periphery of the flange portion 6 of each molded lens 1, 2 is fitted to the inner peripheral surface of the lens frame 4, and the molded lenses 1, 2 are held with respect to the lens frame 4. .

In the lens frame 4, a first step 14 is formed to avoid interference between the vertical burr 8 of the first molded lens 1 and the parallel burr 7 of the second molded lens 2. Further, since a step 6 ′ is provided in the flange portion 6 of the part having the parallel burr 7 on the incident side end face of the second molded lens 2, the parallel direction between the aperture stop 5 and the second molded lens 2 is provided. The burr 7 does not interfere. Further, in order to avoid interference with the vertical burr 8 of the second molded lens 2, the lens frame 4 is shortened instead of being provided with a step.

Note that the parallel burr 7 formed on the incident side end surface of the first molded lens 1 does not block incident light that can pass through the aperture stop 5 at a site near the inner peripheral surface of the lens frame 4. Is formed. Further, the parallel burr 7 formed on the incident side end surface of the second molded lens 2 does not block incident light that can pass through the aperture stop 5 at a portion close to the inner peripheral surface of the lens frame 4. Is formed. Further, the angle of view of the lens unit of this embodiment is 130 ° C. or more.

As shown in FIG. 5, the lens unit of Example 3 stores the first molded lens 1, the second molded lens 2, and these molded lenses 1 and 2 in order from the incident side to the emission side. And an aperture stop 5 provided on the incident side from the incident side end face of the first molded lens 1.

The first molded lens 1 and the second molded lens 2 each have a flange portion 6. Each of the first molded lens 1 and the second molded lens 2 has a parallel burr 7 extending in a direction parallel to the optical axis on the incident side end face. The parallel burr 7 is formed at a position closest to the inner peripheral surface of the lens frame 4 on the incident side end face of the flange portion 6 of each molded lens 1, 2. A step 6 ′ is provided in the flange portion 6 of the portion having the parallel burr 7 on the incident side end faces of the first molded lens 1 and the second molded lens 2, and the tip of the parallel burr 7 is the flange. It protrudes from the part 6.

The first molded lens 1 and the second molded lens 2 each have a vertical burr 8 extending in the direction perpendicular to the optical axis on the exit side end surface. The vertical burrs 8 are formed on the outermost surfaces of the flange portions 6 of the respective molded lenses 1 and 2 at a portion closest to the exit side end surface.

Next, the lens frame 4 that houses the molded lenses 1 and 2 and the aperture stop 5 will be described.
As described above, since the diameter increases in the order of the first molded lens 1 and the second molded lens 2, the diameter of the inner peripheral surface of the lens frame 4 also increases in order according to the diameter of the molded lens to be accommodated. ing. At least a part of the outer periphery of the flange portion 6 of each molded lens 1, 2 is fitted to the inner peripheral surface of the lens frame 4, and the molded lenses 1, 2 are held with respect to the lens frame 4. .

Since the step 6 ′ is provided in the flange portion 6 of the part having the parallel burr 7 on the incident side end face of the first molded lens 1, the parallel burr 7 between the aperture stop 5 and the first molded lens 1 is provided. Will not interfere. A first step 14 is formed in the lens frame 4 to avoid interference between the vertical burrs 8 of the first molded lens 1 and the parallel burrs 7 of the second molded lens 2. Further, since the step 6 ′ is provided in the flange portion 6 of the portion having the parallel burr 7 on the incident side end face of the second molded lens 2, the vertical burr 8 and the second burr 8 of the first molded lens 1 are provided. The burr 7 in the parallel direction of the molded lens 2 does not interfere. Further, a step 16 for avoiding interference with the vertical burr 8 of the second molded lens 2 is formed.

Note that the parallel burr 7 formed on the incident side end surface of the first molded lens 1 does not block incident light that can pass through the aperture stop 5 at a site near the inner peripheral surface of the lens frame 4. Is formed. Further, the angle of view of the lens unit of this embodiment is 130 ° C. or more.

As shown in FIG. 6, the lens unit of Example 4 includes a first molded lens 1, a second molded lens 2, and these molded lenses 1 and 2 from the incident side to the emission side, as in Example 3. And a brightness diaphragm 5 provided on the incident side from the incident side end face of the first molded lens 1.

The first molded lens 1 and the second molded lens 2 each have a flange portion 6. Each of the first molded lens 1 and the second molded lens 2 has a parallel burr 7 extending in a direction parallel to the optical axis on the incident side end face. The parallel burr 7 is formed at a position closest to the inner peripheral surface of the lens frame 4 on the incident side end face of the flange portion 6 of each molded lens 1, 2. A step 6 ′ is provided in the flange portion 6 of the portion having the parallel burr 7 on the incident side end face of the second molded lens 2, so that the tip of the parallel burr 7 does not protrude beyond the flange portion 6. It has become.

The first molded lens 1 and the second molded lens 2 each have a vertical burr 8 extending in the direction perpendicular to the optical axis on the exit side end surface. The vertical burrs 8 are formed on the outermost surfaces of the flange portions 6 of the respective molded lenses 1 and 2 at a portion closest to the exit side end surface.

Next, the lens frame 4 that houses the molded lenses 1 and 2 and the aperture stop 5 will be described.
As described above, since the diameter increases in the order of the first molded lens 1 and the second molded lens 2, the diameter of the inner peripheral surface of the lens frame 4 also increases in order according to the diameter of the molded lens to be accommodated. ing. At least a part of the outer periphery of the flange portion 6 of each molded lens 1, 2 is fitted to the inner peripheral surface of the lens frame 4, and the molded lenses 1, 2 are held with respect to the lens frame 4. .

In the lens frame 4, a first step 14 is formed to avoid interference between the vertical burr 8 of the first molded lens 1 and the parallel burr 7 of the second molded lens 2. Further, since the step 6 ′ is provided in the flange portion 6 of the portion having the parallel burr 7 on the incident side end face of the second molded lens 2, the vertical burr 8 and the second burr 8 of the first molded lens 1 are provided. The burr 7 in the parallel direction of the molded lens 2 does not interfere. Further, a step 16 for avoiding interference with the vertical burr 8 of the second molded lens 2 is formed. Further, the parallel burrs 7 formed on the incident side end face of the first molded lens 1 are fitted to the inner peripheral surface of the lens frame 4 as a part of the flange portion 6.

Note that the parallel burr 7 formed on the incident side end surface of the first molded lens 1 does not block incident light that can pass through the aperture stop 5 at a site near the inner peripheral surface of the lens frame 4. Is formed. Further, the angle of view of the lens unit of this embodiment is 130 ° C. or more.

Next, a capsule endoscope provided with the lens unit of the present invention will be described with reference to FIG.

The illustrated capsule endoscope includes a CCD imager 23 having a lens unit of the present invention in a capsule endoscope housing 22 constituted by a cylindrical cover 20 and a hemispherical transparent cover 21 provided in front and rear thereof. Are provided. In the illustrated example, the example in which the lens unit of Example 1 shown in FIG. 1 is used is shown, but it is also possible to use lens units of other Examples. Since other known internal structures can be used, description thereof is omitted.

The lens unit of the present invention can be used in various fields as long as it can be used for a capsule endoscope and is not limited to its intended use as long as it is a lens unit that combines a plurality of small-diameter molded lenses.

DESCRIPTION OF SYMBOLS 1 1st shaping | molding lens 2 2nd shaping | molding lens 3 3rd shaping lens 4 Lens frame 5 Brightness stop 6 Flange part 6 'Level | step difference 7 Parallel direction burr | flash 8 Vertical direction burr | flash 9 1st metal mold | die member 10 2nd Mold member 11 Third mold member 12 Split line portion in parallel direction 13 Split line portion in vertical direction 14 First step 15 Second step 16 Step 20 Tubular cover 21 Transparent cover 22 Capsule endoscope housing 23 CCD imager

Claims (8)

In a lens unit comprising a plurality of molded lenses having a flange portion and at least one lens frame,
At least one of the molded lenses is
A burr extending in a direction parallel to the optical axis at a portion closest to the inner peripheral surface of the lens frame in the flange portion of the molded lens;
The molded lens different from the lens frame or the molded lens adjacent to the burr extending in the direction parallel to the optical axis of the molded lens does not interfere with the burr extending in the direction parallel to the optical axis of the molded lens. As described above, the lens unit is characterized in that a step is provided in the flange portion of the flange portion of the molded lens having a burr extending in a direction parallel to the optical axis. In a lens unit comprising a plurality of molded lenses having a flange portion and at least one lens frame,
At least one of the molded lenses is
A burr extending in a direction parallel to the optical axis in a portion closest to the inner peripheral surface of the lens frame on the incident side end surface of the flange portion of the molded lens;
The molded lens different from the lens frame or the molded lens adjacent to the burr extending in the direction parallel to the optical axis of the molded lens does not interfere with the burr extending in the direction parallel to the optical axis of the molded lens. As described above, a step is provided on the flange portion of the portion having a burr extending in a direction parallel to the optical axis on the incident side end surface of the flange portion of the molded lens,
Having a burr extending in a direction perpendicular to the optical axis in a portion closest to the exit side end surface of the outer peripheral surface of the flange portion of the molded lens;
The lens frame is arranged with respect to the optical axis of the molded lens on the inner peripheral surface of the lens frame so that the lens frame and a burr extending in a direction perpendicular to the optical axis of the molded lens do not interfere with each other. The lens unit is characterized in that a step is provided near a burr extending in the vertical direction. 3. The lens unit according to claim 1, wherein the plurality of molded lenses have a larger diameter on the exit-side molded lens than on the incident-side molded lens. The lens unit according to any one of claims 1 to 3, wherein each of the plurality of molded lenses has a cylindrical outer shape of the flange portion and satisfies the following conditional expression (1).
1 <φL / tL <6.17 (1)
Here, tL is the total length (mm) of the molded lens, and φL is the outer diameter (mm) of the molded lens. The lens unit according to claim 4, wherein the lens unit is an imaging lens and has an angle of view of 130 degrees or more. The lens unit further has an aperture stop,
Among the plurality of molded lenses, a molded lens that is closer to the incident side than the aperture stop and located closest to the incident side,
A burr extending in a direction parallel to the optical axis in a portion closest to the inner peripheral surface of the lens frame on the incident side end surface of the flange portion of the molded lens;
A portion having a burr extending in the direction parallel to the optical axis on the incident side end face of the molded lens so that the burr extending in a direction parallel to the optical axis of the molded lens does not block incident light that can pass through the aperture stop. The lens unit according to any one of claims 1 to 5, wherein a step is provided in the flange portion. The lens unit further has an aperture stop,
Of the plurality of molded lenses, the molded lens located on the exit side and the most incident side from the aperture stop,
A burr extending in a direction parallel to the optical axis in a portion closest to the inner peripheral surface of the lens frame on the incident side end surface of the flange portion of the molded lens;
A portion having a burr extending in the direction parallel to the optical axis on the incident side end face of the molded lens so that the burr extending in a direction parallel to the optical axis of the molded lens does not block incident light that can pass through the aperture stop. The lens unit according to any one of claims 1 to 5, wherein a step is provided in the flange portion. A capsule endoscope comprising the lens unit according to any one of claims 1 to 8.

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