WO2018207254A1

WO2018207254A1 - Capsule-type endoscope

Info

Publication number: WO2018207254A1
Application number: PCT/JP2017/017531
Authority: WO
Inventors: 内田佳宏; 高田圭輔; 市川啓介
Original assignee: オリンパス株式会社
Priority date: 2017-05-09
Filing date: 2017-05-09
Publication date: 2018-11-15

Abstract

Provided is a capsule-type endoscope capable of obtaining an image with little flare and having a small total length. This capsule-type endoscope 1 is provided with: a columnar main body part 2; a transparent cover 3; an imaging part 4 having an imaging optical system; and a light emitting part 5 having a light-emitting region. The transparent cover 3, the imaging part 4, and the light-emitting part 5 are provided on one side of the main body part 2, the transparent cover 3 has a curved surface region, the curved surface region is located so as to cross a central axis AXc of the main body part, one of the intersection lines formed by a plane including the central axis line AXc and the curved surface region is a curved line having two focal points, the light-emitting part 5 is disposed so that a predetermined region does not include two focal points, and the imaging part 4 is disposed at a position satisfying the following conditional equation (1). 0≦(Lc-La3)/La1≦0.5 (1)

Description

Capsule endoscope

The present invention relates to a capsule endoscope.

In recent years, in the field of endoscopes, an inspection using an endoscope having a capsule housing (hereinafter referred to as “capsule endoscope”) has been performed. In this examination, the subject swallows the capsule endoscope from the mouth. In the capsule endoscope, imaging of the body is performed before the capsule endoscope is discharged from the body.

For example, a capsule endoscope has a transparent cover at one end of a housing. Inside the cover, a light source that illuminates the inside of the body and an imaging unit that images the illuminated part are arranged.

As the light source, for example, a light emitting diode (LED) is used. Moreover, it is preferable that a wide range can be photographed in detail when photographing inside the body. For this reason, an optical system having a wide angle and high resolution is used for the imaging unit.

Patent Document 1 discloses a capsule endoscope. The capsule endoscope according to the first embodiment includes a hemispherical transparent cover, one imaging unit, and a light emitting unit. The light emitting unit is disposed around the imaging unit. The imaging unit is arranged so that the center of curvature of the transparent cover and the entrance pupil position of the optical system coincide. With this arrangement, the occurrence of flare incident on the imaging unit can be suppressed.

Further, the capsule endoscope according to the sixth embodiment includes a hemispherical transparent cover, a plurality of imaging units, and a light emitting unit. The light emitting unit is arranged so that the center position of the radius of curvature of the transparent cover coincides with the exit pupil of the illumination optical system. With this arrangement, the occurrence of flare incident on the imaging unit can be suppressed.

Japanese Patent No. 4363843

In the capsule endoscope of the first embodiment, a hemispherical transparent cover is used, and the imaging unit is arranged so that the center of curvature of the transparent cover coincides with the entrance pupil position of the optical system. Therefore, a large space is required between the transparent cover and the imaging unit. As a result, the total length of the capsule endoscope becomes long.

In the capsule endoscope of the sixth embodiment, a hemispherical transparent cover is used, and the light emitting section is arranged so that the center position of the radius of curvature of the transparent cover coincides with the exit pupil of the illumination optical system. Also in this case, a large space is required between the transparent cover and the imaging unit. As a result, the total length of the capsule endoscope becomes long.

In order to shorten the total length of the capsule endoscope, the transparent cover and the imaging unit may be brought close to each other, or the transparent cover and the light emitting unit may be brought close to each other. However, this makes it easier for flare to occur.

The present invention has been made in view of such problems, and an object of the present invention is to provide a capsule endoscope that can obtain an image with little flare and has a short overall length.

In order to solve the above-described problems and achieve the object, a capsule endoscope according to at least some embodiments of the present invention includes:
A columnar body,
A transparent cover,
An imaging unit having an imaging optical system;
A light emitting unit having a light emitting region,
The transparent cover, the imaging unit, and the light emitting unit are provided on one side of the main body unit,
The transparent cover has a curved area,
The curved area is located so as to intersect the central axis of the main body,
One of the intersecting lines formed by the plane including the central axis and the curved region is a curve having two focal points,
The light emitting part is arranged so that the predetermined area does not include two focal points,
The imaging unit is arranged at a position satisfying the following conditional expression (1).
0 ≦ (Lc−La3) /La1≦0.5 (1)
here,
The predetermined region is a region when the light emitting region of the light emitting unit is projected on a plane including two focal points,
Lc is the distance between the first axis and the central axis,
La1 is the radius in a curve with two focal points,
La3 is the distance between the second axis and the central axis,
The first axis passes through the center of the pupil of the imaging optical system and is parallel to the central axis.
The second axis passes through the focal point and is parallel to the central axis;
It is.

According to the present invention, it is possible to provide a capsule endoscope having an image with little flare and a short overall length.

It is a figure which shows schematic structure of the capsule endoscope of this embodiment. It is a figure which shows the mode of the inside of a capsule type | mold endoscope. It is a figure which shows the mode of the inside in the plane orthogonal to a central axis. It is a figure which shows the mode of the inside in the plane containing a central axis. It is a figure which shows the mode of the inside of a capsule type | mold endoscope. It is a figure which shows the mode of the inside in the plane containing a central axis. It is a figure which shows the mode of the inside in the plane orthogonal to a central axis. It is a figure which shows schematic structure of the capsule endoscope of this embodiment. It is a figure which shows schematic structure of the capsule endoscope of this embodiment. 1 is a cross-sectional view of a capsule endoscope according to a first embodiment. It is a figure which shows sectional drawing of the capsule type endoscope of Example 2. FIG. FIG. 6 is a cross-sectional view of a capsule endoscope according to a third embodiment. It is a figure which shows sectional drawing of the capsule type endoscope of Example 4. FIG. It is a figure which shows sectional drawing of the capsule type endoscope of Example 5. FIG. It is a figure which shows sectional drawing of the capsule type endoscope of Example 5. FIG.

Prior to the description of the examples, the operational effects of the embodiment according to an aspect of the present invention will be described. It should be noted that, when the operational effects of the present embodiment are specifically described, a specific example will be shown and described. However, as in the case of the embodiments to be described later, those exemplified aspects are only a part of the aspects included in the present invention, and there are many variations in the aspects. Therefore, the present invention is not limited to the illustrated embodiment.

The capsule endoscope of the present embodiment includes a columnar main body, a transparent cover, an imaging unit having an imaging optical system, and a light emitting unit having a light emitting region. The transparent cover, the imaging unit, and the light emitting unit are The transparent cover is provided on one side of the main body, has a curved surface area, the curved surface area is located so as to intersect the central axis of the main body, and is formed by a plane including the central axis and the curved surface area. One of the intersecting lines is a curve having two focal points, the light emitting unit is arranged so that the predetermined region does not include the two focal points, and the imaging unit satisfies the following conditional expression (1): It is arranged at a satisfactory position.
0 ≦ (Lc−La3) /La1≦0.5 (1)
here,
The predetermined region is a region when the light emitting region of the light emitting unit is projected on a plane including two focal points,
Lc is the distance between the first axis and the central axis,
La1 is the radius in a curve with two focal points,
La3 is the distance between the second axis and the central axis,
The first axis passes through the center of the pupil of the imaging optical system and is parallel to the central axis.
The second axis passes through the focal point and is parallel to the central axis;
It is.

FIG. 1 shows a schematic configuration of the capsule endoscope of the present embodiment. The capsule endoscope 1 includes a main body 2, a transparent cover 3, an imaging unit 4, and a light emitting unit 5.

The main body 2 is composed of a columnar member. The length of the main body 2 in the direction along the central axis AXc is longer than the length in the direction orthogonal to the central axis AXc. A cavity is formed inside the main body 2. Therefore, it can be said that the main body 2 is formed of a cylindrical member.

The imaging unit 4 and the light emitting unit 5 are arranged in the hollow part. Although not shown, a power source, a signal processing unit, a power reception unit, and a transmission unit are arranged in the hollow portion.

A transparent cover 3 is disposed on one side of the main body 2. The transparent cover 3 is provided so as to protrude from the end surface of the main body. A substantially bowl-shaped bottom is formed on the other side of the main body 2. The bottom part may be formed integrally with the main body part 2 or may be formed separately from the main body part 2.

An imaging unit 4 and a light emitting unit 5 are arranged in the main body unit 2. The imaging unit 4 and the light emitting unit 5 are arranged on one side of the main body unit 2, that is, on the side where the transparent cover 3 is arranged. On the end face on one side of the main body 2, the tip of the imaging unit 4 and the tip of the light emitting unit 5 are located.

The imaging unit 4 has an imaging optical system. An image of the subject is formed by the imaging optical system. A transparent cover 3 is located between the subject and the imaging unit 4. Therefore, the image of the subject is formed through the transparent cover 3. For example, an image sensor is arranged at the position of the subject image. Thereby, a subject can be imaged.

The light emitting unit 5 has a light emitting area. Illumination light is emitted from the light emitting area. A transparent cover 3 is located between the subject and the light emitting unit 5. Therefore, the subject is illuminated through the transparent cover 3.

The state inside the capsule endoscope will be described. FIG. 2 shows the inside of the capsule endoscope. FIG. 2A shows an internal state in a plane orthogonal to the central axis. FIG. 2B shows an internal state in a plane including the central axis.

There are countless planes orthogonal to the central axis AXc. FIG. 2A shows an internal state in a plane PL1 (hereinafter referred to as “plane PL1”) including two focal points Pf. The two focal points Pf will be described later.

The transparent cover 3 has a curved surface area. The curved surface area is located so as to intersect the central axis AXc of the main body 2. In the capsule endoscope 1, the entire transparent cover 3 is a curved region.

There are an infinite number of planes including the central axis AXc. Therefore, there are innumerable intersection lines formed between the plane including the central axis AXc and the curved surface area.

In the capsule endoscope 1, one of the innumerable intersection lines is a curve having two focal points Pf. The shape of the curved surface region in the capsule endoscope 1 is such that a curve having two focal points Pf is included in innumerable intersection lines.

FIG. 2B shows an intersection formed by a plane including the central axis AXc and a curved surface area. Here, a curve having two focal points Pf is shown. As described above, the entire transparent cover 3 is a curved region. Therefore, in FIG. 2B, the entire curve showing the transparent cover 3 represents a curve having two focal points Pf.

As the shape of the curved surface area, for example, there is a semi-elliptical surface. The semi-elliptical surface is obtained by rotating the entire curve showing the transparent cover 3 by 180 degrees with a straight line passing through the two focal points Pf as the rotation axis. By making the shape of the curved surface region a semi-elliptical surface, the amount of protrusion of the transparent cover 3 from the surface PL1 can be reduced as compared with the case where the shape of the transparent cover 3 is a semicircular shape. As a result, the overall length of the capsule endoscope 1 can be shortened.

In the capsule endoscope 1, the light emitting unit 5 is disposed in the center of the main body unit 2. However, the light emitting unit 5 is arranged so that the predetermined region does not include two focal points. The predetermined area is an area when the light emitting area of the light emitting unit is projected onto the surface PL1. As described above, the position of the light emitting unit 5 and the size of the light emitting area are set so that the positions of the two focal points Pf are not included in the predetermined area.

In the capsule endoscope 1, a part of the light emitted from the position of one focal point Pf is reflected by the transparent cover 3. The light reflected by the transparent cover 3 reaches the position of the other focal point Pf.

As described above, the position of the light emitting unit 5 and the size of the light emitting area are set so that the positions of the two focal points Pf are not included in the predetermined area. Therefore, there is no illumination light emitted from the position of the focal point Pf or the vicinity of the focal point Pf. As a result, the illumination light emitted from the light emitting unit 5 does not directly enter the imaging unit 4.

In the capsule endoscope 1, the imaging unit 4 is disposed in the periphery of the main body 2. The imaging unit 4 is arranged so that the center Pp of the pupil of the imaging optical system is located on the line connecting the two focal points Pf. However, in FIG. 2B, the imaging unit 4 is arranged so that the pupil center Pp of the imaging optical system does not coincide with the focal point Pf. Furthermore, the imaging unit 4 is arranged so that the center Pp of the pupil of the imaging optical system is located between the focal point Pf and the outer peripheral surface of the main body unit 2.

In this case, as shown in FIG. 2B, the first axis AXp is located between the second axis AXf and the outer peripheral surface of the main body 2. The first axis AXp is an axis that passes through the center Pp of the pupil of the imaging optical system and is parallel to the center axis AXc. The second axis AXf is an axis that passes through the focal point Pf and is parallel to the central axis AXc.

Furthermore, the imaging unit 4 is disposed at a position that satisfies the conditional expression (1).

Conditional expression (1) is a conditional expression regarding a preferable position of the imaging unit. A preferable position of the imaging unit can be determined by the distance Lc between the first axis AXp and the central axis AXc, the radius La1 in the curve having two focal points, and the distance La3 between the second axis AXf and the central axis AXc.

La1 can be obtained from the intersection formed by the plane including the central axis AXc and the curved surface area, but can also be obtained by another method. For example, an intersection line is formed by the surface PL1 and the curved surface region. This intersection line represents the outer periphery of the curved surface area. La1 is the maximum interval among the intervals between the central axis and the points on the outer periphery of the curved surface area.

Further, La2 can be obtained from the outer periphery of the curved surface area. La2 is the smallest interval among the intervals between the central axis and the points on the outer periphery of the curved surface area.

When the shape of the curved surface area is a semi-elliptical surface, La1 corresponds to the major radius of the ellipse, and La2 corresponds to the minor radius of the ellipse.

A part of the illumination light emitted from the light emitting unit 5 is reflected by the transparent cover 3. When the illumination light reflected by the transparent cover 3 enters the imaging unit 4, flare occurs. The occurrence of flare can be suppressed by satisfying conditional expression (1).

The capsule endoscope according to the present embodiment preferably includes a plurality of imaging units, and each of the plurality of imaging units is preferably arranged so as to satisfy the conditional expression (1).

As described above, there is a semi-elliptical surface as the shape of the curved region. The semi-elliptical surface is obtained by rotating the entire curve showing the transparent cover 3 by 180 degrees with a straight line passing through the two focal points Pf as the rotation axis. Therefore, the semi-elliptical surface is not a rotationally symmetric surface with respect to the central axis AXc.

To make the shape of the curved surface area rotationally symmetric with respect to the central axis AXc, the entire curve showing the transparent cover 3 may be rotated 180 degrees with the central axis AXc as the rotational axis. Even if it does in this way, compared with the case where the shape of a transparent cover is semicircle shape, the protrusion amount of the transparent cover from the surface PL1 can be decreased. As a result, the overall length of the capsule endoscope 1 can be shortened.

FIG. 3 shows an internal state in a plane orthogonal to the central axis. FIG. 3 shows a configuration including one light emitting unit and two imaging units. The shape of the curved surface area in the transparent cover 3 ′ is a rotationally symmetric shape with respect to the central axis AXc. In this case, the two focal points Pf are located on the circumference of a circle centered on the central axis AXc.

The light emitting unit 5 is arranged so that the predetermined area does not include two focal points. Therefore, the illumination light emitted from the light emitting unit 5 does not directly enter the imaging unit 4 or the imaging unit 4 '.

In the transparent cover 3 ′, there are at least two curves having two focal points among intersecting lines formed by the plane including the central axis and the curved surface region. FIG. 3 shows an internal state in the plane PL1 including two focal points Pf and two focal points Pf ′.

The imaging unit 4 has the center Pp of the imaging optical system, and the imaging unit 4 'has the center Pp' of the imaging optical system. The imaging unit 4 is arranged so that the center Pp of the pupil of the imaging optical system is located on the line connecting the two focal points Pf. The imaging unit 4 ′ is arranged so that the center Pp ′ of the pupil of the imaging optical system is positioned on a line connecting the two focal points Pf ′. Both the imaging unit 4 and the imaging unit 4 ′ are arranged at positions that satisfy the conditional expression (1). Therefore, the occurrence of flare can be suppressed.

As described above, it is preferable that the capsule endoscope can capture a wide range in the body in detail. When there is one image pickup unit, the shooting range must be shot with one image pickup unit. Therefore, the imaging magnification in the imaging optical system is reduced.

For example, assume that a lesion having the same size is imaged with an optical system having a small imaging magnification and an optical system having a large imaging magnification. In this case, an image of a lesion is smaller in an optical system with a small imaging magnification than in an optical system with a large imaging magnification.

As a method for observing an image of a lesioned part in detail, for example, there is a method of taking an image of a lesioned part and electronically enlarging the obtained image. However, with this method, the resolution of the image deteriorates due to enlargement. Therefore, detailed observation is not possible.

The capsule endoscope of the present embodiment includes a plurality of imaging units. In this case, the imaging magnification of the imaging optical system can be increased in each imaging unit. Thereby, wide range observation and detailed observation can be made compatible. Further, each imaging unit satisfies the conditional expression (1). Therefore, an image with less flare can be obtained.

In the capsule endoscope of the present embodiment, the imaging unit has an incident surface located closest to the transparent cover, and the light emitting unit has an exit surface located closest to the transparent cover. The imaging unit is preferably arranged such that the first axis and the central axis are parallel to each other, and the incident surface is located closer to the transparent cover than the exit surface in the direction along the central axis.

In this way, the distance between the transparent cover and the imaging unit can be reduced. As a result, the total length of the capsule endoscope can be shortened. Moreover, generation | occurrence | production of flare can be suppressed.

In the capsule endoscope of the present embodiment, the imaging unit has an incident surface located closest to the transparent cover, and the light emitting unit has an exit surface located closest to the transparent cover. It is preferable that the following conditional expression (2) is satisfied.
0.01 ≦ (Zc−Zb) /La1≦1.0 (2)
here,
Zc is the distance from the predetermined surface to the incident surface,
Zb is the distance from the predetermined surface to the exit surface,
La1 is the radius in a curve with two focal points,
The predetermined plane is a plane orthogonal to the central axis and including the center of the pupil of the imaging optical system;
The distance is the distance along the central axis,
The sign of the distance is positive in the direction from the predetermined surface to the transparent cover,
It is.

FIG. 4 shows an internal state in a plane including the central axis. The same components as those in FIG. 2B are denoted by the same reference numerals and description thereof is omitted.

FIG. 4 shows a predetermined surface PL2, a distance Zc from the predetermined surface PL2 to the incident surface 6, and a distance Zb from the predetermined surface PL2 to the exit surface 7. The predetermined plane PL2 is a plane that is orthogonal to the central axis AXc and includes the center of the pupil Pp of the imaging optical system.

When the exit surface 7 is not flat, the distance from the predetermined surface PL2 to the exit surface 7 is different at each point on the exit surface 7. In this case, the distance Zb is the maximum distance among the distances from the predetermined plane PL2 to each point on the exit surface 7.

When the conditional expression (2) is satisfied, the distance between the transparent cover and the imaging unit can be reduced. As a result, the total length of the capsule endoscope can be shortened. Moreover, generation | occurrence | production of flare can be suppressed.

In particular, it is preferable that the conditional expression (2) is satisfied in a state where the imaging unit is arranged so that the first axis and the central axis are parallel to each other.

In the capsule endoscope of the present embodiment, it is preferable that the imaging unit has an incident surface located closest to the transparent cover and satisfies the following conditional expression (3).
−0.5 ≦ Zc / La1 ≦ 0.5 (3)
here,
Zc is the distance from the predetermined surface to the incident surface,
La1 is the radius in a curve with two focal points,
The predetermined plane is a plane orthogonal to the central axis and including the center of the pupil of the imaging optical system;
The distance is the distance along the central axis,
The sign of the distance is positive in the direction from the predetermined surface to the transparent cover,
It is.

In the capsule endoscope of the present embodiment, it is preferable that the curve having two focal points is a part of an ellipse, the short axis of the ellipse coincides with the central axis, and the following conditional expression (4) is satisfied. .
0 ≦ 1-rb / ra ≦ 0.9 (4)
here,
ra is the ellipse major radius,
rb is the short radius of the ellipse,
It is.

The total length of the capsule endoscope can be shortened by not exceeding the upper limit value of conditional expression (4). By not falling below the lower limit value of conditional expression (4), it is possible to reduce the diameter of the transparent cover while securing a space for arranging the imaging unit.

In the capsule endoscope of the present embodiment, the light emitting unit has an exit surface located closest to the transparent cover, and the curve having two focal points is a part of an ellipse, and the minor axis of the ellipse Coincides with the central axis, and the light emitting portion is preferably located inside the first predetermined circle and satisfies the following conditional expression (5).
−0.1 ≦ (La3−Lb− | Z′b | × tan θb) /ra≦0.7 (5)
here,
La3 is the distance between the second axis and the central axis,
Lb is the maximum interval among the intervals between the central axis and each point on the outer edge of the light emitting region,
Z′b is the distance from the plane containing the two focal points to the exit plane,
θb is an angle formed by the central axis and a predetermined direction,
ra is the ellipse major radius,
The first predetermined circle is a circle whose center is located on the central axis and whose radius is the distance La3.
The predetermined direction is a direction of 0.1 × LI,
LI is the light intensity in the direction along the central axis,
It is.

FIG. 5 shows the inside of the capsule endoscope. FIG. 5A shows an internal state in a plane orthogonal to the central axis. FIG. 5B shows an internal state in a plane including the central axis. The same components as those in FIGS. 2A and 2B are denoted by the same reference numerals, and description thereof is omitted.

FIG. 5A shows the maximum distance Lb among the distances between the central axis AXc and each point on the outer edge of the light emitting region. The first predetermined circle is a circle whose center is located on the central axis AXc and whose radius is the distance La3. The first predetermined circle is indicated by a two-dot chain line. The light emitting unit 5 is located inside the first predetermined circle.

FIG. 5B shows the distance Z′b from the surface PL1 to the exit surface 7 and the angle θb formed by the central axis AXc and a predetermined direction. The predetermined direction is a direction that becomes 0.1 × LI. LI is the light intensity in the direction along the central axis.

When the exit surface 7 is not flat, the distance from the predetermined surface to the exit surface 7 is different at each point on the exit surface 7. In this case, Z′b is the maximum distance among the distances from the predetermined surface to each point on the exit surface 7.

The intensity of the light emitted from the light emitting unit 5 is different between the direction along the central axis AXc and the direction intersecting the central axis AXc. In the direction intersecting with the central axis AXc, the intensity of light decreases as the angle formed with the central axis AXc increases. The predetermined direction is a direction in which the light intensity with respect to the direction along the central axis AXc is 10%.

In the light emitting part, it is necessary to ensure a certain illuminance in the shooting range. By not exceeding the upper limit value of conditional expression (5), it is possible to secure a sufficiently wide light emitting region. Therefore, the illuminance necessary for imaging can be obtained.

In order to ensure a wide shooting range, the imaging optical system needs to be a wide-angle optical system. In a wide-angle optical system, the diameter of the optical system tends to be large. Therefore, the diameter of the imaging unit is also increased.

By not falling below the lower limit value of the conditional expression (5), it is possible to secure a space necessary for disposing the imaging unit at a position close to the central axis inside the main body unit while suppressing the occurrence of flare. This also leads to a reduction in capsule diameter.

In the capsule endoscope of the present embodiment, the light emitting unit has an exit surface located closest to the transparent cover, and the curve having two focal points is a part of an ellipse, and the minor axis of the ellipse Coincides with the central axis, the light emitting part is located inside the first predetermined circle, satisfies the following conditional expression (6), and part of the light emitted from the light emitting region is blocked: preferable.
(La3-Lb- | Z'b | × tan θb) / ra <0.05 (6)
here,
La3 is the distance between the second axis and the central axis,
Lb is the maximum interval among the intervals between the central axis and each point on the outer edge of the light emitting region,
Z′b is the distance from the plane containing the two focal points to the exit plane,
θb is an angle formed by the central axis and a predetermined direction,
ra is the ellipse major radius,
The first predetermined circle is a circle whose center is located on the central axis and whose radius is the distance La3.
The predetermined direction is a direction of 0.1 × LI,
LI is the light intensity in the direction along the central axis,
It is.

As described above, in the light emitting unit, it is necessary to ensure a certain illuminance in the shooting range. By not exceeding the upper limit value of conditional expression (6), a sufficiently wide light emitting region can be secured. Therefore, the illuminance necessary for imaging can be obtained.

Furthermore, a part of the light emitted from the light emitting area is shielded. Therefore, the occurrence of flare can be suppressed more effectively. The light shielding may be performed by, for example, a light shielding member.

In the capsule endoscope of the present embodiment, it is preferable that the light emitting unit is located inside the second predetermined circle and satisfies the following conditional expression (7).
0 ≦ Lb / Lc ≦ 0.8 (7)
here,
Lb is the maximum interval among the intervals between the central axis and each point on the outer edge of the light emitting region,
Lc is the distance between the first axis and the central axis,
The second predetermined circle is a circle whose center is located on the central axis and whose radius is the distance La3.
It is.

By satisfying conditional expression (7), the light emitting unit and the imaging unit can be efficiently arranged in a limited space. Therefore, the transparent cover can be reduced, that is, the diameter of the capsule endoscope can be reduced. Furthermore, the occurrence of flare can be suppressed.

In the capsule endoscope according to the present embodiment, it is preferable that the light emitting unit is located inside the first predetermined circle and satisfies the following conditional expression (8).
0 ≦ Lb / La3 ≦ 0.9 (8)
here,
La3 is the distance between the second axis and the central axis,
Lb is the maximum interval among the intervals between the central axis and each point on the outer edge of the light emitting region,
The first predetermined circle is a circle whose center is located on the central axis and whose radius is the distance La3.
It is.

By satisfying conditional expression (8), the light emitting unit and the imaging unit can be efficiently arranged in a limited space. Therefore, the transparent cover can be reduced, that is, the diameter of the capsule endoscope can be reduced. Furthermore, the occurrence of flare can be suppressed.

In the capsule endoscope of the present embodiment, it is preferable that the shape of the curved region is point-symmetric with respect to the central axis.

By doing in this way, it is possible to suppress the occurrence of flare caused by the light emitted from the light emitting unit being reflected multiple times inside the transparent cover and entering the imaging unit.

In the capsule endoscope of the present embodiment, it is preferable that the shape of the intersecting line formed by the curved surface region and the surface including the two focal points is a circle.

In this way, the thickness of the transparent cover can be reduced while maintaining the strength required to maintain the shape required for the capsule endoscope. As a result, it is possible to more effectively suppress incidence of reflected light from the transparent cover to the imaging unit while shortening the overall length of the capsule endoscope.

In the capsule endoscope of the present embodiment, it is preferable that the curve having two focal points is a part of an ellipse, the short axis of the ellipse coincides with the central axis, and the following conditional expression (9) is satisfied. .
0.4 ≦ (ra−La3) / (2 × IH) ≦ 12.5 (9)
here,
ra is the ellipse major radius,
La3 is the distance between the second axis and the central axis,
IH is the image height in the imaging optical system,
It is.

¡By maintaining the shape of the transparent cover appropriately, the outer diameter of the capsule endoscope can be reduced. Conditional expression (9) is a condition in the capsule endoscope that can suppress the occurrence of flare while maintaining the space of the imaging unit and the light emitting unit while maintaining a small outer diameter.

By not exceeding the upper limit value of conditional expression (9), it is possible to secure a space for arranging the light emitting unit while reducing the outer diameter of the capsule endoscope. By not falling below the lower limit value of conditional expression (9), it is possible to secure a space for arranging the imaging unit.

In the capsule endoscope of the present embodiment, the imaging unit has an entrance surface located closest to the transparent cover, and the curve having two focal points is a part of an ellipse, and the minor axis of the ellipse Preferably coincides with the central axis and satisfies the following conditional expression (10).
1.0 ≦ (ra−La3) /Φc≦6.0 (10)
here,
ra is the ellipse major radius,
La3 is the distance between the second axis and the central axis,
Φc is the aperture diameter at the entrance surface,
It is.

¡By maintaining the shape of the transparent cover appropriately, the overall length of the capsule type can be shortened and the outer diameter of the capsule endoscope can be reduced. Conditional expression (10) is a condition in the capsule endoscope that can suppress the occurrence of flare while maintaining the space of the imaging unit and the light emitting unit while maintaining a small outer diameter.

By not exceeding the upper limit value of the conditional expression (10), it is possible to reduce the overall length of the capsule and reduce the outer diameter of the capsule endoscope while securing a space for arranging the light emitting unit. By not falling below the lower limit value of conditional expression (10), it is possible to secure a space for arranging the imaging unit.

The capsule endoscope of the present embodiment has a plurality of imaging units, and the plurality of imaging units satisfy a first imaging unit that satisfies the following conditional expression (11) and a conditional expression (12) below. It is preferable that each imaging unit has an imaging range that overlaps with the other imaging units on the object side of the transparent cover.
60 ° ≦ θc_1 ≦ 140 ° (11)
60 ° ≦ θc_2 ≦ 140 ° (12)
here,
θc_1 is the angle of view of the imaging optical system of the first imaging unit,
θc_2 is the angle of view of the imaging optical system of the second imaging unit,
It is.

When there are a plurality of imaging units, the imaging range when imaging with one imaging unit can be captured with a plurality of imaging units. In this case, the imaging range when imaging with one imaging unit is divided by each imaging unit. Then, in each imaging unit, the imaging magnification of the imaging optical system can be increased. Therefore, more detailed observation can be performed.

By providing the first imaging unit that satisfies the conditional expression (11) and the second imaging unit that satisfies the conditional expression (12), it is possible to achieve both wide-range observation and detailed observation.

In the capsule endoscope of the present embodiment, a convex portion is provided on the other side of the main body, and there are a plurality of imaging units. The plurality of imaging units includes a first imaging unit having a first imaging optical system; A second imaging unit having a second imaging optical system, wherein a part of the imaging range of the first imaging unit overlaps with the imaging range of the second imaging unit, and the first imaging unit is configured by the first imaging optical unit. The second imaging unit is arranged so that the optical axis of the second imaging optical system intersects with the central axis, and the optical axis of the first imaging optical system is centered with the optical axis of the first imaging optical system. It is preferable that the intersection point with the axis and the intersection point between the optical axis and the central axis of the second imaging optical system are both located on the convex side of the surface including the two focal points.

FIG. 6 shows an internal state in a plane including the central axis. The same components as those in FIG. 2B are denoted by the same reference numerals and description thereof is omitted.

The capsule endoscope 10 is provided with a convex portion 12 on the other side of the main body portion 2. The capsule endoscope 10 includes a plurality of imaging units. FIG. 6 shows the state of the first imaging unit 11.

The first imaging unit 11 has a first imaging optical system. The first imaging unit 11 is arranged so that the optical axis AXp1 of the first imaging optical system intersects the central axis AXc. The intersection of the optical axis AXp1 and the central axis AXc of the first imaging optical system is located closer to the convex portion 12 than the surface PL1 including the two focal points Pf.
FIG. 7 shows an internal state in a plane orthogonal to the central axis. FIG. 7A shows a case where three imaging units are arranged, and FIG. 7B shows a case where four imaging units are arranged. The shape of the curved region in the transparent cover is a rotationally symmetric shape with respect to the central axis.

7A includes a first imaging unit 21, a second imaging unit 22, a third imaging unit 23, and a light emitting unit 24. The capsule endoscope 20 illustrated in FIG. The light emitting unit 24 is disposed at the center of the main body. The first imaging unit 21, the second imaging unit 22, and the third imaging unit 23 are disposed so as to surround the light emitting unit 24.

The first imaging unit 21, the second imaging unit 22, and the third imaging unit 23 are arranged in the same manner as the first imaging unit 11 shown in FIG. That is, each imaging unit is arranged so that the optical axis of the imaging element intersects the central axis.

The capsule endoscope 30 shown in FIG. 7B includes a first imaging unit 31, a second imaging unit 32, a third imaging unit 33, a fourth imaging unit 34, and a light emitting unit 35. . The light emitting unit 35 is disposed at the center of the main body. The first imaging unit 31, the second imaging unit 32, the third imaging unit 33, and the fourth imaging unit 34 are arranged so as to surround the light emitting unit 35.

The first imaging unit 31, the second imaging unit 32, the third imaging unit 33, and the fourth imaging unit 34 are arranged in the same manner as the first imaging unit 11 shown in FIG. That is, each imaging unit is arranged so that the optical axis of the imaging element intersects the central axis.

By having a plurality of imaging units, the imaging range when imaging with one imaging unit can be divided by each imaging unit. Then, in each imaging unit, the imaging magnification of the imaging optical system can be increased. Therefore, more detailed observation can be performed. Moreover, it is possible to achieve both wide-range observation and detailed observation.

In the capsule endoscope of the present embodiment, the first imaging unit has a first incident surface that is located closest to the transparent cover, and the light emitting unit is an emission that is located closest to the transparent cover. The curve having a surface and having two focal points is preferably a part of an ellipse, the minor axis of the ellipse coincides with the central axis, and the following conditional expression (14) is satisfied.
0.1 ≦ zb / ra ≦ 1.0 (14)
here,
zb is the distance from the virtual surface including the first incident surface to the exit surface, and the distance in the direction along the optical axis of the first imaging optical system;
ra is the ellipse major radius,
It is.

FIG. 6 shows a surface PL3 including the first incident surface 13 (hereinafter referred to as “surface PL3”) and a distance zb from the surface PL3 to the exit surface 7. The distance zb is a distance in the direction along the optical axis AXp1 of the first imaging optical system. In the light emitting unit 5, the emission surface 7 is parallel to the surface PL3.

When the conditional expression (14) is satisfied, the distance between the transparent cover and the imaging unit is shortened. Therefore, the total length of the capsule endoscope can be shortened. Moreover, generation | occurrence | production of flare can be suppressed more effectively.

In the capsule endoscope of the present embodiment, it is preferable that the lens arranged closest to the object side of the imaging optical system is a positive lens.

In this way, the principal point position can be located on the object side. Therefore, the total length of the imaging unit can be shortened. As a result, the total length of the capsule endoscope can be shortened.

In the capsule endoscope of the present embodiment, it is preferable that the lens arranged closest to the object side of the imaging optical system is a negative lens.

In this way, the entrance pupil can be positioned on the object side. Therefore, the area of the opening can be reduced. As a result, the degree of freedom of arrangement of the imaging unit is increased, and furthermore, incidence of reflected light from the transparent cover on the imaging unit can be suppressed.

In the capsule endoscope of the present embodiment, it is preferable that the capsule endoscope has a side light emitting portion, the side light emitting portion is disposed on the side surface of the main body portion, and satisfies the following conditional expression (15).
70 ° ≦ ε ≦ 110 ° (15)
here,
ε is the angle formed by the light axis of the light emitting part and the light axis of the side light emitting part,
It is.

FIG. 8 shows a schematic configuration of the capsule endoscope of the present embodiment. FIG. 8 is a schematic configuration in a plane including the central axis.

The capsule endoscope 40 includes a main body portion 41, a bottom portion 42, a transparent cover 43, a first imaging optical system 44, a first imaging element 45, a second imaging optical system 46, and a second imaging element 47. And a light emitting unit 48, a first side light emitting unit 49a, and a second side light emitting unit 49b.

In the capsule endoscope 40, a transparent cover 43 is disposed on one side of the main body 41. A bottom portion 42 is formed on the other side of the main body portion 41. The shape of the bottom part 42 is a substantially bowl shape. The bottom part 42 may be formed integrally with the main body part 41 or may be formed separately from the main body part 41.

The first imaging optical system 44 and the first imaging element 45 constitute a first imaging unit. The second imaging optical system 46 and the second imaging element 47 constitute a second imaging unit.

The light emitting unit 48 is disposed at a position including the central axis AXc. In the light emitting unit 48, the light emitting area faces the direction of the transparent cover 43. When the axis indicating the direction in which the light emitting area is directed is the lamp axis of the light emitting unit 48, the lamp axis of the light emitting unit 48 is a direction substantially parallel to the central axis AXc.

1st side light emission part 49a and 2nd side light emission part 49b are arrange | positioned at the outer peripheral surface of the main-body part 41. As shown in FIG. Both the lamp axis AXi1 of the first side light emitting unit 49a and the lamp axis AXi2 of the second side light emitting unit 49b are substantially perpendicular to the central axis AXc. Therefore, in the capsule endoscope 40, the conditional expression (15) is satisfied.

Satisfying conditional expression (15) can ensure sufficient brightness for the imaging range.

In the capsule endoscope of the present embodiment, it is preferable that the curve having two focal points is a part of an ellipse, the short axis of the ellipse coincides with the central axis, and the following conditional expression (16) is satisfied. .
0.01 ≦ Dt / ra ≦ 0.2 (16)
here,
Dt is the thickness on the central axis of the transparent cover,
ra is the ellipse major radius,
It is.

In the capsule endoscope of the present embodiment, the imaging unit is arranged so that the center of the pupil of the imaging optical system is located between the focal point and the outer peripheral surface of the main body unit. On the other hand, the central axis of the transparent cover substantially coincides with the central axis of the main body. For this reason, the central axis of the transparent cover is decentered with respect to the optical axis of the imaging optical system.

The occurrence of decentration aberrations can be suppressed by not exceeding the upper limit value of conditional expression (16). Therefore, good resolution performance can be ensured even in detailed observation.

¡Flare occurs when the transparent cover is deformed. By not falling below the lower limit value of conditional expression (16), it is possible to suppress degradation of resolution performance due to such flare.

The capsule endoscope of the present embodiment preferably satisfies the following conditional expression (17).
ndc ≦ 1.7 (17)
here,
ndc is the refractive index at the d-line of the material of the transparent cover,
It is.

Satisfying conditional expression (17) makes it possible to suppress reflection of illumination light on the transparent cover. As a result, the occurrence of flare can be suppressed.

In the capsule endoscope of the present embodiment, it is preferable that the thickness of the transparent cover is uniform within the effective diameter.

As described above, in the capsule endoscope of this embodiment, the central axis of the transparent cover is decentered with respect to the optical axis of the imaging optical system. Therefore, the occurrence of decentration aberration can be suppressed by making the thickness of the transparent cover uniform within the effective diameter. Therefore, good resolution performance can be ensured even in detailed observation.

In the capsule endoscope of the present embodiment, it is preferable that the thickness of the transparent cover increases with increasing distance from the central axis within the effective beam diameter.

By doing so, it is possible to widen the angle of view of the imaging optical system and widen the illumination area of the light emitting unit.

The capsule endoscope of the present embodiment preferably includes a plurality of lenses and performs imaging using all of the plurality of lenses or performs imaging using a part of the plurality of lenses.

In this way, stereo shooting can be performed. As a result, more detailed observation is possible.

The capsule endoscope of the present embodiment includes a transparent cover different from the transparent cover, an imaging unit different from the imaging unit, and a light emitting unit different from the light emitting unit on the other side of the main body unit. It is preferable to have.

FIG. 9 shows a schematic configuration of the capsule endoscope of the present embodiment. FIG. 9 is a schematic configuration in a plane including the central axis. The same components as those in FIG.

The capsule endoscope 50 includes a transparent cover 51, a third imaging optical system 52, a third imaging element 53, a fourth imaging optical system 54, a fourth imaging element 55, and a light emitting unit 56. .

In the capsule endoscope 50, not only the transparent cover 43 is disposed on one side of the main body 41, but also the transparent cover 51 is disposed on the other side of the main body 41.

The third imaging optical system 52 and the third imaging element 53 constitute a third imaging unit. The fourth imaging optical system 54 and the fourth imaging element 55 constitute a fourth imaging unit.

In the capsule endoscope 50, an imaging unit different from the imaging unit arranged on one side is arranged on the other side. In addition, a light emitting unit different from the light emitting unit arranged on one side is arranged on the other side. Therefore, a wider range can be photographed.

The capsule endoscope of the present embodiment may have a plurality of light emitting units, and each light emitting unit may have a different wavelength spectrum.

In the capsule endoscope of the present embodiment, the light emitting unit may have an illumination optical system.

Hereinafter, examples of the capsule endoscope according to the present embodiment will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

FIG. 10 shows a cross-sectional view of the capsule endoscope of the first embodiment. FIG. 10A shows an internal state in a plane including the central axis. FIG. 10B shows an internal state in a plane orthogonal to the central axis.

The capsule endoscope of Example 1 includes a transparent cover C, an imaging optical system OBJ, and a light emitting unit ILL.

Both sides of the transparent cover C are semi-elliptical surfaces. The number of imaging optical systems OBJ and the number of light emitting units ILL are one each. The light emitting unit ILL is disposed at the center of the main body, and the imaging optical system OBJ is disposed at the periphery of the main body.

The light emitting part ILL is arranged so that the lamp axis is parallel to the central axis AXc. The imaging optical system OBJ is arranged so that the optical axis AXp is parallel to the central axis AXc.

The imaging optical system OBJ includes, in order from the object side, a negative meniscus lens L1 having a convex surface facing the object side, a biconvex positive lens L2, a biconvex positive lens L3, and a positive meniscus lens L4 having a convex surface facing the object side. Have. The aperture stop S is disposed between the biconvex positive lens L2 and the biconvex positive lens L3.

The aspheric surfaces are provided on a total of five surfaces including the image side surface of the negative meniscus lens L1, the object side surface of the biconvex positive lens L2, the image side surface of the biconvex positive lens L3, and both surfaces of the positive meniscus lens L4. .

FIG. 11 shows a cross-sectional view of the capsule endoscope of the second embodiment. FIG. 11 shows an internal state in a plane including the central axis.

The capsule endoscope of the second embodiment includes a transparent cover C, an imaging optical system OBJ1, an imaging optical system OBJ2, and a light emitting unit ILL.

Both sides of the transparent cover C are semi-elliptical surfaces. The number of imaging optical systems OBJ is two, and the number of light emitting units ILL is one. The light emitting unit ILL is disposed at the center of the main body, and the imaging optical system OBJ1 and the imaging optical system OBJ2 are both disposed around the main body.

The light emitting part ILL is arranged so that the lamp axis is parallel to the central axis AXc. The imaging optical system OBJ1 and the imaging optical system OBJ2 are both arranged so that the optical axis AXp is parallel to the central axis AXc.

The imaging optical system OBJ1 and the imaging optical system OBJ2 are the same as the imaging optical system OBJ of the first embodiment.

FIG. 12 shows a cross-sectional view of the capsule endoscope of the third embodiment. FIG. 12A shows an internal state in a plane including the central axis. FIG. 12B shows an internal state in a plane orthogonal to the central axis.

The capsule endoscope of Example 3 has a transparent cover C, an imaging optical system OBJ, and a light emitting unit ILL.

The imaging optical system OBJ includes, in order from the object side, a negative meniscus lens L1 having a convex surface facing the object side, a biconvex positive lens L2, and a negative meniscus lens L3 having a convex surface facing the image side. The aperture stop S is disposed between the negative meniscus lens L1 and the biconvex positive lens L2.

The aspheric surfaces are provided on a total of four surfaces including the image side surface of the negative meniscus lens L1, both surfaces of the biconvex positive lens L2, and the image side surface of the negative meniscus lens L3.

FIG. 13 shows a cross-sectional view of the capsule endoscope of the fourth embodiment. FIG. 13 shows an internal state in a plane including the central axis.

The capsule endoscope of Example 4 includes a transparent cover C, an imaging optical system OBJ, and a light emitting unit ILL.

The imaging optical system OBJ includes, in order from the object side, a negative meniscus lens L1 having a convex surface facing the object side, a biconvex positive lens L2, a positive meniscus lens L3 having a convex surface facing the image side, and a convex surface facing the object side. Negative meniscus lens L4. The aperture stop S is disposed between the biconvex positive lens L2 and the positive meniscus lens L3.

The aspheric surfaces are provided on a total of four surfaces including the image side surface of the negative meniscus lens L1, the image side surface of the positive meniscus lens L3, and both surfaces of the negative meniscus lens L4.

FIG. 14 and FIG. 15 show cross-sectional views of the capsule endoscope of the fifth embodiment. FIG. 14 shows an internal state in a plane including the central axis. FIG. 15 is an enlarged view of the imaging optical system.

The capsule endoscope of Example 5 includes a transparent cover C1, an imaging optical system OBJ1, an imaging optical system OBJ2, and a light emitting unit ILL.

Both sides of the transparent cover C are semi-elliptical surfaces. The number of imaging optical systems OBJ and the number of light emitting units ILL are both two. The light emitting unit ILL is disposed at the center of the main body, and the imaging optical system OBJ1 and the imaging optical system OBJ2 are both disposed around the main body.

The light emitting part ILL is arranged so that the lamp axis intersects the central axis AXc. The imaging optical system OBJ1 and the imaging optical system OBJ2 are both arranged so that the optical axis AXp intersects the central axis AXc.

The imaging optical system OBJ includes, in order from the object side, a biconvex positive lens L1, a planoconcave negative lens L2, a positive meniscus lens L3 having a convex surface facing the image side, and a planoconcave negative lens L4. The aperture stop S is disposed on the object side of the biconvex positive lens L1. A cover glass C2 is disposed between the plano-concave negative lens L4 and the image plane I.

The numerical data of each of the above examples is shown below. In the surface data, r is the radius of curvature of each lens surface, d is the distance between the lens surfaces, nd is the refractive index of the d-line of each lens, νd is the Abbe number of each lens, and * is an aspherical surface.

In the various data, f is the focal length of the entire system, ω is the half angle of view, IH is the image height, FNO. Is the F number.

The aspherical shape is expressed by the following equation when the optical axis direction is z, the direction orthogonal to the optical axis is y, the cone coefficient is k, and the aspherical coefficients are A4, A6, A8, A10, A12. expressed.
z = (y ² / r) / [1+ {1− (1 + k) (y / r) ² } ^1/2 ]
+ A4y ⁴ + A6y ⁶ + A8y ⁸ + A10y ¹⁰ + A12y ¹² +
In the aspheric coefficient, “E−n” (n is an integer) indicates “10 ⁻ⁿ ”. The symbols of these specification values are common to the numerical data of the examples described later.

Numerical examples 1, 2
Unit mm

Surface data surface number r d nd νd
Object ∞ ∞
1 * 7.446 0.371 1.585 30
2 * 7.001 5.838
3 61.844 0.47 1.5311 56
4 * 0.742 0.633
5 * 2.117 1.042 1.635 23.9
6 -3.546 0.049
7 ∞ (Aperture) 0.116
8 15.633 0.63 1.5311 56
9 * -1.049 0.14
10 * 2.752 0.618 1.5311 56
11 * 3.144 1.051
Image plane ∞

Aspheric data first surface
k = 0.2
Second side
k = 0.2
4th page
k = -0.732
5th page
k = 0.000, A4 = -0.247
9th page
k = 0.000, A4 = -0.061, A6 = 0.506
10th page
k = 0.000, A4 = -0.228, A6 = 0.033
11th page
k = 0.000, A4 = -0.169, A6 = -0.019, A8 = -0.016

Various data f 1
2ω 130
IH 1.12
FNO. 4.5

Numerical Example 3
Unit mm

Surface data surface number r d nd νd
Object ∞ ∞
1 * 8.131 0.624 1.585 30
2 * 7.256 4.371
3 49.957 0.437 1.5311 56
4 * 0.826 0.901
5 ∞ (Aperture) 0.092
6 * 2.595 0.59 1.635 23.9
7 * -0.868 0.062
8 -7.323 0.5 1.5311 56
9 * -8.423 1.4
Image plane ∞

Aspheric data first surface
k = 0.4
Second side
k = 0.4
4th page
k = 0.000, A4 = -0.234, A6 = 0.077
6th page
k = 0.000, A4 = 0.435, A6 = -1.875
7th page
k = 0.000, A4 = 0.487
9th page
k = 0.000, A4 = 0.037, A6 = 0.063

Various data f 1
2ω 120
IH 1.07
FNO. 4.3

Numerical Example 4
Unit mm

Surface data surface number r d nd νd
Object ∞ ∞
1 * 7.452 0.364 1.585 30
2 * 6.864 5.5
3 60.637 0.441 1.5311 56
4 * 0.728 0.588
5 * 15.781 0.882 1.635 23.9
6 -1.896 0.049
7 ∞ (Aperture) 0.098
8 -29.543 0.618 1.5311 56
9 * -0.824 0.137
10 * 1.382 0.608 1.5311 56
11 * 0.705 0.985
Image plane ∞

Aspheric data first surface
k = 0.2
Second side
k = 0.2
4th page
k = 0.987
5th page
k = 0.000, A4 = 0.109
9th page
k = 0.000, A4 = -0.295, A6 = 0.11
10th page
k = 0.000, A4 = -0.505, A6 = -0.076
11th page
k = 0.000, A4 = -0.988, A6 = -0.1, A8 = 2.89E-03

Various data f 1
2ω 130
IH 0.91
FNO. 4.9

Numerical Example 5
Unit mm

Surface data surface number r d nd νd
Object ∞ ∞
1 * 7.91 0.2 1.59 30
2 * 7.69 4
3 ∞ (Aperture) -0.809
4 * 0.901 0.383 1.5305 55.7
5 * -2.493 0.023
6 * ∞ 0.174 1.634 24
7 * 1.44 0.249
8 * -1.131 0.342 1.5305 55.7
9 * -0.375 0.031
10 * ∞ 0.264 1.5305 55.7
11 * 0.488 0.425
12 ∞ 0.18 1.51633 64.1
13 ∞ 0.343
Image plane ∞

Aspheric data first surface
k = 0.1
Second side
k = 0.1
4th page
k = 0.114, A4 = -0.29151396, A6 = 2.3581128, A8 = -48.569499,
A10 = 314.37057, A12 = -863.95816
5th page
k = -59.568, A4 = -0.58501645, A6 = -9.5685171, A8 = 48.402206,
A10 = 151.47177, A12 = -938.08007
6th page
k = 0.000, A4 = 0.094848455, A6 = -11.893684, A8 = 58.185908,
A10 = 148.00698, A12 = -755.63172
7th page
k = -3.194, A4 = 0.59870838, A6 = -3.6506976, A8 = 11.160053,
A10 = -14.830006, A12 = 141.4102
8th page
k = -4.557, A4 = -0.46819278, A6 = 2.4717458, A8 = -2.4978831,
A10 = -2.2760385, A12 = -72.294739
9th page
k = -3.126, A4 = -1.0401939, A6 = 2.0588846, A8 = 0.37197606,
A10 = 21.235709, A12 = -44.214973
10th page
k = 0.000, A4 = -0.67695487, A6 = 0.53465864, A8 = 1.0518579,
A10 = -1.4108677, A12 = 0.28622263, A14 = 0.13521064
11th page
k = -8.223, A4 = -0.76835953, A6 = 1.2955772, A8 = -2.0585815,
A10 = 2.0984017, A12 = -1.2869036, A14 = 0.36112621

Various data f 1.8
2ω 37
IH 1.4
FNO. 5.5

Next, the values of conditional expressions in each example are listed below. In addition,-(hyphen) indicates that there is no corresponding configuration.

Example 1 Example 2 Example 3
(1) (Lc-La3) / La1 0.03 0.03 0.07
(2) (Zc-Zb) / La1 0.04 0.07 0.12
(3) Zc / La1 0.00 0.00 0.12
(4) 1-rb / ra 0.09 0.09 0.15
(5), (6) (La3-Lb-
| Z'b | × tanθb) / ra 0.72 0.36 1.17
(7) Lb / Lc 0.63 0.67 0.61
(8) Lb / La3 0.68 0.72 0.68
(9) (ra-La3) / (2 × IH) 1.81 1.81 1.50
(10) (ra-La3) / Φc 1.26 1.26 2.13
(11) θc_1 130.0 130.0 120.0
(12) θc_2-130.0-
(14) zb / ra---
(16) Dt / ra 0.05 0.05 0.09

Example 4 Example 5
(1) (Lc-La3) / La1 0.10 0.23
(2) (Zc-Zb) / La1--
(3) Zc / La1 0.03-
(4) 1-rb / ra 0.09 0.05
(5), (6) (La3-Lb-
| Z'b | × tanθb) / ra--0.33
(7) Lb / Lc-0.38
(8) Lb / La3-0.66
(9) (ra-La3) / (2 × IH) 2.20 1.88
(10) (ra-La3) / Φc 2.68 5.27
(11) θc_1 130.0 70.0
(12) θc_2-70.0
(14) zb / ra-0.20
(16) Dt / ra 0.05 0.03

Next, the parameter values in each example are listed below. In addition,-(hyphen) indicates that there is no corresponding configuration.
Example 1 Example 2 Example 3
La1 (ra) 6.8 6.8 6.9
La2 (rb) 6.2 6.2 5.8
La3 2.8 2.8 3.7
Lb 1.9 2.0 2.5
Lc 3.0 3.0 4.1
Zb -0.3 -0.5 0.0
| Z'b | 0.3 0.5 0.0
Zc 0.0 0.0 0.8
tanθb 75.0 80.0 70.0
IH 1.1 1.1 1.1
θc_1 130.0 130.0 120.0
θc_2-130.0-
Dt 0.4 0.4 0.6
ndc 1.585 1.585 1.585
Φc 3.2 3.2 1.5
zb---

Example 4 Example 5
La1 (ra) 6.8 7.5
La2 (rb) 6.2 7.2
La3 2.8 2.3
Lb-1.5
Lc 3.4 4.0
Zb--
| Z'b |-1.5
Zc 0.2-
tanθb-80.0
IH 0.9 1.4
θc_1 130.0 70.0
θc_2-70.0
Dt 0.4 0.2
ndc 1.585 1.585
Φc 1.5 1.0
zb-1.5

It should be noted that the present invention can take various modifications without departing from the spirit of the present invention.

As described above, the present invention is suitable for a capsule endoscope that can obtain an image with less flare and has a short overall length.

DESCRIPTION OF SYMBOLS 1 Capsule type endoscope 2 Main-body part 3, 3 'Transparent cover 4, 4' imaging part 5 Light emission part 6 Incident surface 7 Outgoing surface 10 Capsule type endoscope 11 1st imaging part 12 Convex part 20 Capsule type endoscope 21 First imaging unit 22 Second imaging unit 23 Third imaging unit 24 Light emitting unit 30 Capsule endoscope 31 First imaging unit 32 Second imaging unit 33 Third imaging unit 34 Fourth imaging unit 35 Light emitting unit 40 Capsule type Endoscope 41 Body 42 Bottom 43 Transparent cover 44 First imaging optical system 45 First imaging element 46 Second imaging optical system 47 Second imaging element 48 Light emitting part 49a First side light emitting part 49b Second side light emitting part 50 Capsule Type Endoscope 51 Transparent Cover 52 Third Imaging Optical System 53 Third Imaging Element 54 Fourth Imaging Optical System 55 Fourth Imaging Element 56 Light Emitting Unit AXc Central Axis AXp First Axis, Optical Axis AXf Second Axis AX p1 Optical axis of the first imaging optical system AXi1 Lamp axis of the first side light emitting unit AXi2 Lamp axis of the second side light emitting unit Pf focal point Pf ′ position Pp Center of the pupil of the imaging optical system PL1 Surface including two focal points PL2 Predetermined Surface PL3 surface including the first incident surface La1 radius La2 in the curve having two focal points La2 the minimum interval among the distances between the central axis and the points on the outer periphery of the curved surface area La3 between the second axis and the central axis Interval Lb The maximum interval among the intervals between the central axis and each point on the outer edge of the light emitting region Lc The interval between the first axis and the central axis Zb The distance from the predetermined plane to the exit plane Z′b From the plane PL1 Distance from the exit surface Zc Distance from the predetermined surface to the entrance surface zb Distance from the surface PL3 to the exit surface θb Angle formed by the central axis and the predetermined direction OBJ, OBJ1, OBJ2 Imaging optical systems L1, L2, L3, L4 Lens I LL Light emitting part I Image surface S Aperture stop C, C1 Transparent cover C2 Cover glass

Claims

A columnar body,
A transparent cover,
An imaging unit having an imaging optical system;
A light emitting unit having a light emitting region,
The transparent cover, the imaging unit, and the light emitting unit are provided on one side of the main body unit,
The transparent cover has a curved region,
The curved surface region is located so as to intersect the central axis of the main body portion,
One of the intersection lines formed by the plane including the central axis and the curved region is a curve having two focal points,
The light emitting unit is arranged so that a predetermined area does not include the two focal points,
The capsule endoscope is characterized in that the imaging unit is disposed at a position that satisfies the following conditional expression (1).
0 ≦ (Lc−La3) /La1≦0.5 (1)
here,
The predetermined region is a region when a light emitting region of the light emitting unit is projected on a plane including the two focal points,
Lc is the distance between the first axis and the central axis,
La1 is the radius in the curve with the two focal points,
La3 is the distance between the second axis and the central axis,
The first axis passes through the center of the pupil of the imaging optical system and is parallel to the central axis;
The second axis passes through the focal point and is parallel to the central axis;
It is.
A plurality of the imaging unit;
2. The capsule endoscope according to claim 1, wherein each of the plurality of imaging units is arranged so as to satisfy the conditional expression (1).
The imaging unit has an incident surface located closest to the transparent cover,
The light emitting unit has an exit surface located closest to the transparent cover;
The imaging unit is arranged so that the first axis and the central axis are parallel to each other,
2. The capsule endoscope according to claim 1, wherein the incident surface is located closer to the transparent cover than the exit surface in a direction along the central axis.
The imaging unit has an incident surface located closest to the transparent cover,
The light emitting unit has an exit surface located closest to the transparent cover;
The capsule endoscope according to claim 1, wherein the following conditional expression (2) is satisfied.
0.01 ≦ (Zc−Zb) /La1≦1.0 (2)
here,
Zc is the distance from the predetermined surface to the incident surface,
Zb is the distance from the predetermined surface to the exit surface,
La1 is the radius in the curve with the two focal points,
The predetermined plane is a plane orthogonal to the central axis and including the center of the pupil of the imaging optical system;
The distance is a distance along the central axis,
The sign of the distance is plus in the direction from the predetermined surface toward the transparent cover,
It is.
The imaging unit has an incident surface located closest to the transparent cover,
The capsule endoscope according to claim 1, wherein the following conditional expression (3) is satisfied.
−0.5 ≦ Zc / La1 ≦ 0.5 (3)
here,
Zc is the distance from the predetermined surface to the incident surface,
La1 is the radius in the curve with the two focal points,
The predetermined plane is a plane orthogonal to the central axis and including the center of the pupil of the imaging optical system;
The distance is a distance along the central axis,
The sign of the distance is plus in the direction from the predetermined surface toward the transparent cover,
It is.
The curve having the two focal points is part of an ellipse;
The minor axis of the ellipse coincides with the central axis;
The capsule endoscope according to claim 1, wherein the following conditional expression (4) is satisfied.
0 ≦ 1-rb / ra ≦ 0.9 (4)
here,
ra is the major radius of the ellipse,
rb is the short radius of the ellipse,
It is.
The light emitting unit has an exit surface located closest to the transparent cover;
The curve having the two focal points is part of an ellipse;
The minor axis of the ellipse coincides with the central axis;
2. The capsule endoscope according to claim 1, wherein the light emitting unit is located inside a first predetermined circle and satisfies the following conditional expression (5):
−0.1 ≦ (La3−Lb− | Z′b | × tan θb) /ra≦0.7 (5)
here,
La3 is the distance between the second axis and the central axis,
Lb is the maximum interval among the intervals between the central axis and each point on the outer edge of the light emitting region,
Z′b is the distance from the plane including the two focal points to the exit surface,
θb is an angle formed by the central axis and a predetermined direction,
ra is the major radius of the ellipse,
The first predetermined circle is a circle whose center is located on the central axis and whose radius is the distance La3.
The predetermined direction is a direction of 0.1 × LI,
LI is the light intensity in the direction along the central axis,
It is.
The light emitting unit has an exit surface located closest to the transparent cover;
The curve having the two focal points is part of an ellipse;
The minor axis of the ellipse coincides with the central axis;
The light emitting unit is located inside the first predetermined circle and satisfies the following conditional expression (6):
The capsule endoscope according to claim 1, wherein a part of the light emitted from the light emitting region is shielded.
(La3-Lb- | Z'b | × tan θb) / ra <0.05 (6)
here,
La3 is the distance between the second axis and the central axis,
Lb is the maximum interval among the intervals between the central axis and each point on the outer edge of the light emitting region,
Z′b is the distance from the plane including the two focal points to the exit surface,
θb is an angle formed by the central axis and a predetermined direction,
ra is the major radius of the ellipse,
The first predetermined circle is a circle whose center is located on the central axis and whose radius is the distance La3.
The predetermined direction is a direction of 0.1 × LI,
LI is the light intensity in the direction along the central axis,
It is.
2. The capsule endoscope according to claim 1, wherein the light emitting unit is located inside a second predetermined circle and satisfies the following conditional expression (7).
0 ≦ Lb / Lc ≦ 0.8 (7)
here,
Lb is the maximum interval among the intervals between the central axis and each point on the outer edge of the light emitting region,
Lc is the distance between the first axis and the central axis,
The second predetermined circle is a circle whose center is located on the central axis and whose radius is the distance La3.
It is.
2. The capsule endoscope according to claim 1, wherein the light emitting unit is located inside a first predetermined circle and satisfies the following conditional expression (8):
0 ≦ Lb / La3 ≦ 0.9 (8)
here,
La3 is the distance between the second axis and the central axis,
Lb is the maximum interval among the intervals between the central axis and each point on the outer edge of the light emitting region,
The first predetermined circle is a circle whose center is located on the central axis and whose radius is the distance La3.
It is.
The capsule endoscope according to claim 1, wherein a shape of the curved region is a point-symmetric shape with respect to the central axis.
The capsule endoscope according to claim 1, wherein a shape of an intersecting line formed by the curved surface area and the surface including the two focal points is a circle.
The curve having the two focal points is part of an ellipse;
The minor axis of the ellipse coincides with the central axis;
The capsule endoscope according to claim 1, wherein the following conditional expression (9) is satisfied.
0.4 ≦ (ra−La3) / (2 × IH) ≦ 12.5 (9)
here,
ra is the major radius of the ellipse,
La3 is the distance between the second axis and the central axis,
IH is the image height in the imaging optical system,
It is.
The imaging unit has an incident surface located closest to the transparent cover,
The curve having the two focal points is part of an ellipse;
The minor axis of the ellipse coincides with the central axis;
The capsule endoscope according to claim 1, wherein the following conditional expression (10) is satisfied.
1.0 ≦ (ra−La3) /Φc≦6.0 (10)
here,
ra is the major radius of the ellipse,
La3 is the distance between the second axis and the central axis,
Φc is the aperture diameter at the entrance surface,
It is.
A plurality of the imaging units;
The plurality of imaging units include a first imaging unit that satisfies the following conditional expression (11), and a second imaging unit that satisfies the following conditional expression (12):
The capsule endoscope according to claim 1, wherein each of the imaging units has an imaging range that overlaps with another imaging unit on the object side of the transparent cover.
60 ° ≦ θc_1 ≦ 140 ° (11)
60 ° ≦ θc_2 ≦ 140 ° (12)
here,
Θc_1 is the angle of view of the imaging optical system of the first imaging unit,
Θc_2 is an angle of view of the imaging optical system of the second imaging unit,
It is.
A convex part is provided on the other side of the main body part,
A plurality of the imaging units;
The plurality of imaging units include a first imaging unit having a first imaging optical system and a second imaging unit having a second imaging optical system,
A part of the imaging range of the first imaging unit overlaps with the imaging range of the second imaging unit,
The first imaging unit is arranged so that an optical axis of the first imaging optical system intersects the central axis,
The second imaging unit is arranged so that an optical axis of the second imaging optical system intersects the central axis,
Both the intersection of the optical axis of the first imaging optical system and the central axis, and the intersection of the optical axis of the second imaging optical system and the central axis are both more convex than the plane including the two focal points. The capsule endoscope according to claim 1, wherein the capsule endoscope is located on a side of a portion.
The first imaging unit has a first incident surface located closest to the transparent cover,
The light emitting unit has an exit surface located closest to the transparent cover;
The curve having the two focal points is part of an ellipse;
The minor axis of the ellipse coincides with the central axis;
The capsule endoscope according to claim 16, wherein the following conditional expression (14) is satisfied.
0.1 ≦ zb / ra ≦ 1.0 (14)
here,
zb is a distance from the virtual surface including the first incident surface to the exit surface, and a distance along the optical axis of the first imaging optical system;
ra is the major radius of the ellipse,
It is.
The capsule endoscope according to claim 1, wherein the lens disposed closest to the object side of the imaging optical system is a positive lens.
The capsule endoscope according to claim 1, wherein the lens disposed closest to the object side of the imaging optical system is a negative lens.
Having a side light emitter,
The side light emitting part is disposed on a side surface of the main body part,
The capsule endoscope according to claim 1, wherein the following conditional expression (15) is satisfied.
70 ° ≦ ε ≦ 110 ° (15)
here,
ε is an angle formed by the lamp axis of the light emitting unit and the lamp axis of the side light emitting unit,
It is.
The curve having the two focal points is part of an ellipse;
The minor axis of the ellipse coincides with the central axis;
The capsule endoscope according to claim 1, wherein the following conditional expression (16) is satisfied.
0.01 ≦ Dt / ra ≦ 0.2 (16)
here,
Dt is the thickness of the transparent cover on the central axis,
ra is the major radius of the ellipse,
It is.
The capsule endoscope according to claim 1, wherein the following conditional expression (17) is satisfied.
ndc ≦ 1.7 (17)
here,
ndc is the refractive index at the d-line of the material of the transparent cover,
It is.
The capsule endoscope according to claim 1, wherein the thickness of the transparent cover is uniform within an effective diameter.
2. The capsule endoscope according to claim 1, wherein the thickness of the transparent cover increases with increasing distance from the central axis within the effective light beam diameter.
Having a plurality of lenses,
2. The capsule endoscope according to claim 1, wherein imaging is performed using all of the plurality of lenses, or imaging is performed using a part of the plurality of lenses.
The second side of the main body has a transparent cover different from the transparent cover, an imaging unit different from the imaging unit, and a light emitting unit different from the light emitting unit. Item 2. The capsule endoscope according to Item 1.