JP2012235821A - Endoscope lateral side illumination optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope lateral side illumination optical system not requiring a light guide which is bent, capable of enhancing operatability by shortening the length of a hard part of the front end part of an endoscope, uniforming light distribution, suppressing the parallax of an illumination field and a visual field even in near observation as much as possible, capable of illuminating in good transmission efficiency, and capable of downsizing as a whole.SOLUTION: The endoscope lateral side illumination optical system has a light source part 11 having an emission opening 11a1 directed to a front end side of an endoscope, a reflecting surface 12a reflecting illumination light emitted from the emission opening of the light source part to a lateral side, and a light transmission optical part 13 which is arranged in an outer periphery of a side view observation optical system 20, in which crosssection is formed in a general U-shape and an outer side surface 13a is formed in a cylindrical shape around a predetermined axis O along a longitudinal direction of the endoscope, and which guides the illumination light reflected by the reflecting surface to an object to be observed in the lateral side, the emission end 13c of the light transmission optical part is formed in an elongate shape along the longitudinal direction of the endoscope and is arranged in the lateral side of the observation window 21 of the lateral view observation optical system.

Description

  The present invention is an endoscope that illuminates an observation object located in the field of view of a side-view observation optical system from a tip portion, which is configured integrally or detachably with a main body of an industrial-use side-view type endoscope. The present invention relates to a side illumination optical system.

  Conventionally, examples of this type of side illumination optical system include those described in Patent Documents 1 to 3 below.

JP 2005-287851 A JP 2010-194191 A Japanese Patent Laid-Open No. 06-138400

  As shown in FIG. 5, the side illumination optical system 51 described in Patent Document 1 includes a light emitter 51a for illuminating an observation target, and an illumination lens 51b provided at the tip of the light emitter 51a. In FIG. 5, 52 is a side-view observation optical system, and 52a and 52b are an objective lens and an image sensor provided in the side-view observation optical system 52, respectively. The light emitter 51a includes a light source (not shown) and a light guide 51a1. The illumination lens 51b is disposed closer to the distal end side of the endoscope than the objective lens 52a. The light guide 51a1 is bent so that the emission end faces the illumination lens 51b1.

Further, as shown in FIG. 6A, the side illumination optical system 61 described in Patent Document 2 includes a light guide fiber bundle 61a and an illumination range conversion unit 61b. In FIG. 6, 62 is a side-view observation optical system, and 62a and 62b are an observation window provided in the side-view observation optical system 62 and a prism that bends the optical path in the side view direction. The light guide fiber bundle 61a is bent so that the emission end faces the illumination range conversion unit 61b. Further, the light guide fiber bundle 61a is disposed on the distal end side of the endoscope with respect to the observation window 62a.
As illustrated in FIG. 6B, the illumination range conversion unit 61b includes a reflection plate 61b1 having a first reflection surface 61b11 and a second reflection surface 61b12, and a conversion unit main body 61b2. The conversion unit main body 61b2 is formed in a transparent cylindrical shape in which the observation window 62a and the light guide fiber bundle 61a of the side-view observation optical system 62 can be arranged, and further has an opening 61b21 for exposing the observation window 62a to the outside. I have.
The side illumination optical system 61 described in Patent Document 2 reflects light emitted from the exit end of the light guide fiber bundle 61a on the first reflecting surface 61b11 in the outer peripheral direction of the conversion unit main body 61b2, and converts the conversion unit main body 61b2. The light traveling inward is further reflected by the second reflecting surface 61b12 toward the outside of the conversion unit main body 61b2.

Moreover, the side illumination optical system 71 as an example described in Patent Document 3 includes a light guide 71a and an optical element 71b as shown in FIG. In FIG. 7, 72a and 72b are prisms and objective lenses that bend the optical path in the side view direction provided in the side view observation optical system 72, and 73 is an image guide.
The light guide 71a is formed in a U-shape (FIG. 7 (c)) or a kamaboko-type (FIG. 7 (d)) that surrounds the side-view observation optical system 72 and the image guide 73. The optical element 71b includes an incident surface 71b1 that is in contact with the emission end of the light guide 71a, a spherical reflection surface 71b2 that reflects light incident from the incident surface 71b1, and an emission surface 71b3 that emits light reflected by the reflection surface 71b2. And is disposed closer to the distal end side of the endoscope than the side-view observation optical system 72.
And the side illumination optical system 71 described in the example described in Patent Document 3 takes in the light emitted from the exit end of the light guide 71a from the incident surface 71b1 of the optical element 71b and reflects it by the spherical reflecting surface 71b2. Thus, the light is once condensed and then diffused and emitted from the emission surface 71b3.

Further, as shown in FIG. 8, a side illumination optical system 71 ′ as another example described in Patent Document 3 includes a light guide 71a ′ and an optical element 71b ′. In FIG. 8, 72a 'and 72b' are prisms and objective lenses that bend the optical path in the side viewing direction provided in the side viewing observation optical system 72 ', and 73' is an image guide.
The optical element 71b ′ is formed by cutting a hollow cylinder covering the outer periphery of the side-view observation optical system 72 ′ by cutting the upper part in parallel with the axial direction of the cylinder, and has a U-shaped cross section. Then, the optical element 71b ′ has an incident surface 71b1 ′ in contact with the exit end of the light guide 71a ′ and the other surface opposite to the incident surface 71b1 ′ as a reflection surface of the prism 72a ′ of the side-view observation optical system 72 ′. It has a reflecting surface 71b2 'inclined along and an exit surface 71b3' perpendicular to the incident surface 71b1 '. The light guide 71a ′ is formed in a U shape in accordance with the incident surface 71b1 ′ of the optical element 71b ′, or is arranged in a U shape as an assembly of light guide bundles.
And the side illumination optical system 71 ′ described in another example described in Patent Document 3 takes in the light emitted from the exit end of the light guide 71a ′ from the entrance surface 71b1 ′ of the optical element 71b ′, and reflects the light. The light is reflected by 71b2 ′ and emitted from the exit surface 71b3 ′.

However, if the light guide is bent and its exit end is arranged closer to the endoscope tip than the observation window of the side-view observation optical system, as in the side illumination optical systems described in Patent Documents 1 and 2, the corresponding amount is reduced. The hard part at the tip of the endoscope becomes long and the operability deteriorates.
Further, if the exit end of the side illumination optical system and the observation window of the side observation optical system are arranged along the longitudinal direction of the endoscope front end portion, the illumination field and the visual field are easily separated. For this reason, uneven light distribution due to parallax between the field of view of the side observation system and the illumination field of the illumination optical system is likely to occur, and in close-up observation, only the field of view on the tip side in the observation image becomes bright and halation occurs. easy.
In order to shorten the length of the endoscope tip, it is desirable to reduce the radius of curvature of the part where the light guide is bent. However, if the light guide is bent with a small radius of curvature, the fiber will be easily broken, causing light leakage and light quantity. Loss occurs and transmission efficiency deteriorates.

On the other hand, the side illumination optical system described in Patent Document 3 does not bend the light guide.
However, like the side illumination optical system 71 in the example of FIG. 7, when the optical element 71 b is disposed closer to the distal end side of the endoscope than the prism 72 a that bends the optical path in the side view direction of the side view observation optical system 72, As in the case of the side illumination optical systems described in Patent Documents 1 and 2, the hard part at the distal end of the endoscope becomes longer and the operability is deteriorated.
7 and 8, the light guides 71a and 71a 'are formed in a U-shape or a semicircular shape, or the light guide bundles are assembled into a U-shape. In the semicircular arrangement, the processing and arrangement of the light guide becomes complicated.

  The present invention has been made in view of such conventional problems, and does not require a bent light guide, and can shorten the length of the hard portion at the endoscope tip to improve operability. To provide an endoscope side illumination optical system that makes light uniform, suppresses parallax between the illumination field and field of view as much as possible even in close-up observations, enables illumination with good transmission efficiency, and enables compactness as a whole. It is an object.

  In order to achieve the above object, an endoscope side illumination optical system according to the present invention includes a side view observation optical system having an observation window for taking in light from an observation object located on the side of an endoscope tip. A side illumination optical system for illuminating an observation object located on the side of the endoscope distal end in an endoscope, the light source having an exit opening facing the distal end of the endoscope, and the light source A reflecting surface that reflects the illumination light emitted from the exit opening of the side to the side, and an outer periphery of the side-view observation optical system, and a cross-section is formed in a substantially U shape or a substantially J shape, The side surface is formed in a cylindrical shape centering on a predetermined axis along the longitudinal direction of the endoscope, and the illumination light reflected by the reflecting surface is placed on the observation object side located on the side of the endoscope distal end portion. An optical transmission optical unit that guides light toward the end, and an exit end of the optical transmission optical unit is an endoscope. In the longitudinal direction is formed in an elongated shape, and is characterized in that it is arranged on the side of the observation window.

  In the endoscope side illumination optical system of the present invention, it is preferable that a scattering surface is provided in the vicinity of the exit end of the light transmission optical unit.

In the endoscope side illumination optical system of the present invention, it is preferable that the following conditional expression is satisfied.
1.45 <n _IN
Here, n _IN is the refractive index of the optical transmission optical unit.

In the endoscope side illumination optical system of the present invention, it is preferable that the following conditional expression is satisfied.
0.4 <r / R
Here, R is a radius of a circular arc having a cylindrical shape on the outer surface of the optical transmission optical unit, and r is a distance from the center of the circular arc to the center of the emission opening of the light source unit.

In the endoscope side illumination optical system of the present invention, it is preferable that the following conditional expression is satisfied.
1.4 <n _IN / n _OUT
Here, n _IN is a refractive index of the optical transmission optical unit, and n _OUT is a refractive index of a substance in contact with the outer surface of the optical transmission optical unit.

  In the endoscope side illumination optical system of the present invention, it is preferable that a reflection film is provided on the outer surface of the light transmission optical unit.

  In the endoscope side illumination optical system according to the present invention, the reflecting surface includes an emission optical axis of the light source unit and a center of a circular arc that forms a cylindrical shape on the outer surface of the light transmission optical unit. An angle formed by a virtual straight line perpendicular to the emission optical axis in the plane and the reflection optical axis of the reflection surface is 90 ° ± 20 °, and the normal of the reflection surface and the emission of the light source unit It is preferable to arrange in an orientation where the angle formed with the optical axis is 45 ° ± 20 °.

  According to the present invention, there is no need for a bent light guide, the length of the hard portion of the endoscope can be shortened to improve operability, the light distribution is uniform, and the illumination field and field of view can be obtained even in close-up observation. Thus, it is possible to obtain an endoscope side illumination optical system that can reduce the parallax as much as possible, perform illumination with good transmission efficiency, and can be made compact as a whole.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which shows the principal part structure of the endoscope side illumination optical system concerning 1st Embodiment of this invention, (a) is the front view which looked at the endoscope side illumination optical system from the light source part side, (b ) Is a side view of (a), (c) is a view of (a) as viewed from above, and (d) is a perspective view of the endoscope side illumination optical system as viewed from the distal end side of the endoscope. It is explanatory drawing which shows the principal part structure of the endoscope side illumination optical system concerning 2nd Embodiment of this invention, (a) is the front view which looked at the endoscope side illumination optical system from the light source part side, (b ) Is a side view of (a), (c) is a view of (a) as viewed from above, and (d) is a perspective view of the endoscope side illumination optical system as viewed from the distal end side of the endoscope. It is explanatory drawing which shows the principal part structure of the endoscope side illumination optical system concerning 3rd Embodiment of this invention, (a) is the front view which looked at the endoscope side illumination optical system from the light source part side, (b ) Is a side view of (a), (c) is a view of (a) as viewed from above, and (d) is a perspective view of the endoscope side illumination optical system as viewed from the distal end side of the endoscope. It is explanatory drawing which shows the external appearance of the endoscope front-end | tip part using the endoscope side illumination optical system of each said embodiment of this invention, (a) is a type with which the front-end | tip part was comprised integrally with the main-body part. The figure which shows the example used for the side type | mold endoscope, (b) is the figure which shows the example used for the endoscope front part for side views of the type by which the front-end | tip part was comprised so that attachment or detachment was possible. It is. It is sectional drawing of the side endoscope front-end | tip part which shows the principal part structure of the side illumination optical system of patent document 1. FIG. It is explanatory drawing which shows the principal part structure of the side illumination optical system of patent document 2, (a) is sectional drawing of a side-view endoscope front-end | tip part, (b) is a perspective view of a side illumination optical system. . It is explanatory drawing which shows the principal part structure of an example of the side illumination optical system described in patent document 3, (a) is sectional drawing in alignment with the optical axis of a side endoscope front-end | tip part, (b) is side view endoscope. FIG. 6 is a plan view of the mirror tip, (c) is a side view of the side illumination optical system viewed from the endoscope tip, and (d) is a side view showing a modification of (c). FIG. 7 is an explanatory diagram showing a configuration of a main part of another example of the side illumination optical system described in Patent Document 3, in which (a) is a cross-sectional view taken along the optical axis of the side endoscope tip, and (b) is a side view. FIG. 4 is a plan view of the endoscope front end portion, (c) is a side view of the side illumination optical system viewed from the endoscope front end side, and (d) is a perspective view of an optical element constituting the side illumination optical system. It is explanatory drawing which shows the basic structural example of the type of side illumination optical system of the type provided with the light guide which bent the front-end | tip part like the side illumination optical systems of patent documents 1, 2. FIG. FIG. 10 is an explanatory view showing a light distribution state of illumination light in the field of view of the side-view observation optical system by the side illumination optical system of the type shown in FIG. 9, wherein (a) shows a light distribution state during normal observation; b) is a diagram showing a light distribution state in the close-up observation. In the side illumination optical system of the example of FIG. 8, it is explanatory drawing which shows a structure at the time of providing one light guide, without adjusting to the shape of entrance plane 71b1 'of optical element 71b', (a) is side illumination. The side view which looked at the optical system from the endoscope front end side, (b) is a cross-sectional view along the optical axis of the distal end portion of the side endoscope. The relationship between the radius of the circular arc which makes the cylindrical shape in the outer surface of the optical transmission optical part which comprises the endoscope side illumination optical system of this invention, and the distance from the center of an arc to the center of the exit opening of a light source part is shown. In the explanatory diagram, (a) is a diagram showing a configuration example in which the emission opening of the light source unit is arranged at a position away from the outer surface, (b) is a configuration in which the emission opening of the light source unit is arranged at a position close to the outer surface It is a figure which shows an example.

Prior to the description of the embodiments, the effects of the present invention will be described while showing the problems of the prior art in detail in the drawings.
FIG. 9 is an explanatory view showing a basic configuration example of a side illumination optical system of a type provided with a light guide having a bent tip portion like the side illumination optical systems described in Patent Documents 1 and 2. . A configuration example similar to this basic configuration is shown as a prior art in FIG.
The endoscope distal end portion 81 is configured integrally with the endoscope main body portion 82 or configured to be detachable in an adapter manner. FIG. 9 shows an example in which the endoscope distal end portion 81 is configured as an adapter type.
The side-view observation optical system 83 includes an objective lens 83a and a prism 83b having a reflecting surface 83b1. In FIG. 9, 83c and 83d are lenses, and 83e is an image sensor. In the example of FIG. 9, the objective lens 83a also serves as an observation window.
The side illumination optical system 84 includes a light source (not shown), a light guide 84a, and an illumination lens 84b. The light guide 84a is bent so that the exit end 84a1 faces the illumination lens 84b, so that light can be transmitted in the viewing direction of the side-view observation optical system 83.
In such a configuration, the objective lens 83a of the side-view observation optical system 83 and the illumination lens 84b of the side illumination optical system 84 each have a predetermined diameter. For this reason, the distance d between the incident optical axis of the side-viewing optical system 83 and the exit optical axis of the side illumination optical system 84 is greatly increased, and accordingly, the length L of the endoscope distal end portion 81 is also increased. become longer.

By the way, in endoscopic observation, in order to observe a narrow space such as the inside of a bent thin tube, it is necessary to shorten the hard portion at the distal end of the endoscope as much as possible to improve operability.
However, when the length L of the endoscope distal end portion 81 is increased, the hard portion at the endoscope distal end is increased correspondingly, and accordingly, the operability is deteriorated, and the portion that can be observed is limited.

  Further, as the distance d between the incident optical axis of the side-view observation optical system 83 and the exit optical axis of the side illumination optical system 84 increases, the field of view of the side-view observation optical system 83 and the illumination of the side illumination optical system 84 increase. The parallax with the field becomes larger. As a result, for example, as shown in FIG. 10A, light distribution unevenness that becomes darker from the near point (the distal end side of the endoscope) to the far point is likely to occur. As shown in b), the distal-end region of the endoscope in the field of view of the side-view observation optical system 83 is too bright, causing halation, while the opposite-side region is darkened and tends to adversely affect the obtained observation image.

  In addition, in order to be able to observe a narrow space in an endoscope, in addition to shortening the length of the distal end portion of the endoscope, it is necessary to reduce the diameter of the distal end portion of the endoscope as much as possible. . For this reason, even if the light guide 84a is bent as shown in the example of FIG. 9, it is desired to bend it with a radius of curvature as small as possible.

  However, it is very difficult to mold the light guide with a small radius of curvature, which results in poor yield. In addition, when attempting to bend and mold with a small radius of curvature, the molded light guide breaks and light leaks, and transmission efficiency tends to decrease. In this regard, in the example of Patent Document 1 shown in FIG. 5, the radius of curvature for bending the light guide 51a1 is increased by arranging straight from the tip surface of the objective system of the observation optical system to the imaging surface. Then, the diameter of the distal end portion of the endoscope becomes large, and a narrow space cannot be observed.

  Further, as shown in FIG. 9, when the endoscope distal end portion 81 is configured as a unit that can be attached to and detached from the endoscope main body portion 82, the endoscope is further provided in the light guide 84 a 1 provided in the endoscope main body portion 81. The light guide 84a2 of the mirror tip 81 is added, and the light transmission efficiency is reduced accordingly.

  Further, as described above, in the side illumination optical system described in Patent Document 3, both of the examples of FIGS. 7 and 8 are adapted to the shapes of the incident surfaces 71b1 and 71b1 ′ of the optical elements 71b and 71b ′. The light guides 71a and 71a 'are formed in a U-shape or a semicircular shape, or the light guide bundles are arranged in a U-shape or a semicircular shape as an aggregate, so that the processing and arrangement of the light guide becomes complicated. Here, for example, in the side illumination optical system of the example of FIG. 8, as shown in FIG. 11, if a single light guide is provided without matching the shape of the incident surface 71 b 1 ′ of the optical element 71 b ′, The light reflected by 71b2 'tends to be biased, the light distribution state is biased, and the transmission efficiency is deteriorated.

  Furthermore, in the side illumination optical system of the example of FIG. 7, as described above, a part of the reflection surface 71b2 and the exit surface 71b3 of the optical element 71b is bent by the prism 72a that bends the optical path in the side view direction of the observation optical system 72. Since the configuration is also arranged at the distal end side of the endoscope, the hard portion at the distal end of the endoscope is lengthened accordingly, and the operability is deteriorated.

However, the endoscope side illumination optical system according to the present invention is an endoscope provided with a side-view observation optical system having an observation window for taking in light from an observation object located on the side of the endoscope tip. A side illumination optical system for illuminating an observation object located on the side of an endoscope front end, and a light source having an exit opening facing the distal end of the endoscope, and emitted from the exit opening of the light source A reflecting surface that reflects the illumination light to the side and an outer periphery of the side-view observation optical system, the cross section is formed in a substantially U shape or a substantially J shape, and the outer surface is in the longitudinal direction of the endoscope A light transmission optical unit that guides the illumination light reflected by the reflecting surface toward the observation target side that is located to the side of the distal end of the endoscope. The exit end of the light transmission optical unit is formed in an elongated shape along the longitudinal direction of the endoscope, and It is disposed on the side of the window.
For this reason, according to the endoscope side illumination optical system of the present invention, a light guide for bending is not required, and bright side illumination can be performed with high transmission efficiency. In addition, since the distance d between the optical axis incident from the side-view observation optical system and the optical axis emitted from the elongated emission end of the optical transmission optical unit can be shortened as much as possible, uneven image distribution and proximity Halation during observation can be reduced as much as possible. Furthermore, the length L of the endoscope distal end can be shortened, the operability is improved, and a narrower space can be observed.

In the endoscope side illumination optical system of the present invention, it is preferable to provide a scattering surface in the vicinity of the exit end of the light transmission optical unit.
In this way, uneven distribution of illumination light can be eliminated.

In the endoscope side illumination optical system of the present invention, it is preferable that the following conditional expression (1) is satisfied.
1.45 <n _IN (1)
Here, n _IN is the refractive index of the optical transmission optical unit.
If the conditional expression (1) is satisfied, the critical angle becomes small and the light incident on the inside of the optical transmission optical part is easily totally reflected on the outer surface, so that the transmission efficiency can be increased.

In the endoscope side illumination optical system of the present invention, it is preferable that the following conditional expression (2) is satisfied.
0.4 <r / R (2)
Here, R is a radius of a circular arc having a cylindrical shape on the outer surface of the optical transmission optical unit, and r is a distance from the center of the circular arc to the center of the emission opening of the light source unit.
In order to save the space of the optical transmission optical unit and transmit the light incident on the optical transmission optical unit, it is desirable that the arrangement is such that the exit opening of the light source unit and the outer surface of the optical transmission optical unit are as close as possible to each other.

FIG. 12 shows the radius of a circular arc that forms a cylindrical shape on the outer surface of the light transmission optical unit constituting the endoscope side illumination optical system of the present invention, and the distance from the center of the circular arc to the center of the exit opening of the light source unit. In the explanatory diagram showing the relationship, (a) is a diagram showing a configuration example in which the emission opening of the light source unit is arranged at a position away from the outer surface, (b) is arranged at a position where the emission opening of the light source unit is close to the outer surface It is a figure which shows the example of a structure made.
As shown in FIG. 12A, when the emission opening A of the light source unit is arranged at a position away from the outer surface B, the space of the inner region C for arranging the side-view observation optical system is reduced accordingly. In addition, since the incident angle of the illumination light emitted from the light source unit and reflected by the reflecting surface (not shown) to the outer surface B is reduced, the outer surface B is not totally reflected by that amount and is transmitted through the outer surface B to the outside. The amount of light that leaks out increases and the transmission efficiency tends to decrease. Further, if a reflection film is provided on the outer surface B, leakage of light to the outside can be prevented, but if the incident angle to the outer surface B is small, the light is reflected in the direction of the inner surface D, and the inner surface D and the outer surface By repeating the reflection with B, the amount of light that is absorbed and lost by the reflective film increases, and the transmission efficiency tends to decrease accordingly.

  On the other hand, as shown in FIG. 12B, when the emission opening A of the light source unit is arranged at a position close to the outer surface B, the space of the inner region C for arranging the side-view observation optical system is correspondingly increased. Widely secured. In addition, since the incident angle of the illumination light emitted from the light source unit and reflected by the reflecting surface (not shown) to the outer surface B is increased, the light is easily totally reflected by the outer surface B, and the outside of the outer surface B is increased accordingly. The amount of light that leaks out decreases, the light beam moves while being totally reflected along the outer surface B, and transmission efficiency is improved. In addition, since most of the region that propagates while totally reflecting the illumination light beam is a region along the outer surface B, the inner surface D can be brought closer to the outer surface B, and a large space in the inner region C can be secured. Further, it is possible to secure the minimum space necessary for arranging the side-view observation optical system in the space of the inner region C and to bring the outer surface B closer to the inner surface D. In this way, the diameter of the endoscope tip can be further reduced.

  However, in the endoscope side illumination optical system of the present invention, if the conditional expression (2) is satisfied, a space for arranging the inner observation optical system can be secured, and the transmission efficiency can be improved. .

In the endoscope side illumination optical system of the present invention, it is preferable that the following conditional expression (3) is satisfied.
1.4 <n _IN / n _OUT (3)
Here, n _IN is the refractive index of the optical transmission optical unit, and n _OUT is the refractive index of the substance in contact with the outer surface of the optical transmission optical unit.
If the conditional expression (3) is satisfied, the ratio of the refractive index of the optical transmission optical unit to the refractive index of the substance in contact with the outer surface of the optical transmission optical unit increases, so that the light emitted from the light source unit and reflected by the reflective surface Can easily be totally reflected on the outer surface, and as a result, transmission efficiency can be increased.

In the endoscope side illumination optical system of the present invention, it is preferable that a reflection film is provided on the outer surface of the light transmission optical unit.
In this way, the optical transmission is such that the refractive index does not satisfy the conditional expression (1), and the light emitted from the light source unit and reflected by the reflecting surface is incident on the outer surface at an angle smaller than the critical angle. Even in the optical part, it is possible to prevent light from leaking to the outside of the reflecting surface and to improve the transmission efficiency.

In the endoscope side illumination optical system of the present invention, the reflecting surface is emitted within a virtual plane including the emission optical axis of the light source unit and the center of a circular arc that forms a cylindrical shape on the outer surface of the light transmission optical unit. The angle formed by the virtual straight line perpendicular to the optical axis and the reflection optical axis of the reflection surface is 90 ° ± 20 °, and the angle formed by the normal line of the reflection surface and the emission optical axis of the light source unit is 45. It is preferable to arrange in the direction of ° ± 20 °.
If the reflecting surface is arranged in such a range, illumination light can be transmitted while maintaining good transmission efficiency via the outer surface of the optical transmission optical unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First Embodiment FIG. 1 is an explanatory diagram showing the configuration of the main part of an endoscope side illumination optical system according to a first embodiment of the present invention. FIG. 1 (a) shows the endoscope side illumination optical system on the light source side. Front view, (b) is a side view of (a), (c) is a view of (a) from above, (d) is a view of the endoscope side illumination optical system from the end of the endoscope It is a perspective view.
The endoscope side illumination optical system 10 according to the present embodiment includes a light source unit 11, a reflection surface 12 a, and a light transmission optical unit 13.
The light source unit 11 includes a light source (not shown) such as halogen, xenon, or LED, and a light guide 11a, and is disposed along the longitudinal direction of the endoscope.
An exit end 11a1 of the light guide 11a forms an exit opening of the light source unit 11 and faces the distal end side of the endoscope.
As shown in FIG. 1C, the reflection surface 12 a is provided on each surface constituting the wedge surface in the wedge-shaped portion 12 cut into a V shape, and is emitted from the emission opening of the light source unit 11. The illuminated light is divided into two and reflected to the sides.

The light transmission optical unit 13 is disposed on the outer periphery of the side-view observation optical system 20. In FIG. 1A, reference numeral 21 denotes an objective lens, and 22 denotes a deflecting member that bends the optical path in the side view direction. In the example of FIG. 1, the incident surface 21 a of the objective lens 21 forms an observation window in the side-view observation optical system 20.
In addition, the optical transmission optical unit 13 is formed in a cylindrical shape centered on the axis O1 along the longitudinal direction of the endoscope, and the outer surface 13a is formed in a substantially U-shaped cross section together with the wedge-shaped unit 12. Has been. And the light transmission optical part 13 guides the illumination light reflected by the reflective surface 12a toward the observation object side located in the side of the endoscope front-end | tip part. The inner side surface 13b of the optical transmission optical unit 13 is formed in a concave shape. The arc of the outer side surface 13a has an angle of 180 degrees or more around the axis O1.
The exit end 13 c of the light transmission optical unit 13 is formed in an elongated shape along the longitudinal direction of the endoscope, and is disposed on the side of the observation window 21 a of the side-view observation optical system 20.
The optical transmission optical unit 13 is formed using a material such as plastic or high refractive index glass having a refractive index of 1.45 or more.

Further, the endoscope side illumination optical system 10 of the first embodiment has a radius of a circular arc that forms a cylindrical shape on the outer side surface 13a of the light transmission optical unit 13 as R, and an emission opening of the light source unit 11 from the center O1 of the circular arc ( When the distance to the center O2 of the exit end 11a1) of the light guide 11a is r, the following conditional expression (2) is satisfied.
0.4 <r / R (2)
The outer surface 13a of the optical transmission optical unit 13 is in contact with air, the refractive index of the optical transmission optical unit 13 is n _IN , and the refractive index of the substance (air) in contact with the outer surface 13a of the optical transmission optical unit 13 is n. _{When OUT} , the following conditional expression (3) is satisfied.
1.4 <n _IN / n _OUT (3)
The optical transmission optical unit 13 may include a reflective film on the outer surface 13a.
Further, as shown in FIG. 1A, the reflection surface 12a is within a virtual plane including the emission optical axis of the light source unit 11 and the center O1 of a circular arc that forms a cylindrical shape on the outer surface 13a of the light transmission optical unit 13. (Not shown), an imaginary straight line perpendicular to the emission optical axis of the light source unit 11 (a straight line connecting the center O1 of the arc in FIG. 1A and the center O2 of the emission opening of the light source unit 11) and the reflecting surface 12a. 1 is 90 ° ± 20 °, and as shown in FIG. 1 (c), the angle β between the normal line of the reflecting surface 12a and the emission optical axis of the light source unit 11 is It is arranged in the direction of 45 ° ± 20 °.
Further, an elongated rectangular optical member 14 having a scattering surface 14 a is provided on the exit optical axis in the vicinity of the exit end 13 c of the light transmission optical unit 13. The scattering surface 14 a is sandwiched between _two optical members 14 ₁ and 14 ₂ that constitute the elongated rectangular optical member 14. Incidentally, the scattering surface 14a are two optical members 14 _1, instead of between 14 ₂ may be provided on the incident surface 14 ₁ a or exit surface 14 ₂ a of the elongated rectangular optical member 14.

  In the side illumination optical system 10 of the present embodiment configured as described above, the illumination light emitted from the exit opening of the light source unit 11 is divided into two by the reflecting surface 12a and reflected to the respective sides, The light enters each outer surface 13a. Each outer surface 13a guides incident illumination light to an emission end 13c formed in an elongated shape while totally reflecting or reflecting. The illumination light emitted from the exit end 13c enters the optical member 14, is scattered by the scattering surface 14a, and exits the optical member 14. The illumination light emitted from the optical member 14 illuminates the visual field range of the side-view observation optical system 20.

  According to the endoscope side illumination optical system 10 of the present embodiment, a light guide for bending is not required, and bright side illumination can be performed with high transmission efficiency. In addition, since the distance d between the optical axis incident on the side-view observation optical system 20 and the optical axis emitted from the exit end of the light guide can be shortened as much as possible, light distribution unevenness of the observation image is reduced as much as possible. Halation during close-up observation can be reduced. Furthermore, since the length L of the distal end portion of the endoscope can be shortened, a narrower space can be observed.

In addition, since the scattering surface 14a is provided in the vicinity of the exit end 13c of the light transmission optical unit 13, uneven distribution of illumination light can be eliminated.
Further, since the conditional expression (1) is satisfied, the critical angle becomes small, and the light incident on the inside of the optical transmission optical unit 13 is easily totally reflected by the outer surface 13a, so that the transmission efficiency can be increased.
Further, since the conditional expression (2) is satisfied, a large space in the inner region in which the side-view observation optical system 20 is disposed can be secured, and the transmission efficiency can be improved.
Further, since the conditional expression (3) is satisfied, the ratio of the refractive index of the light transmission optical unit 13a to the refractive index of the substance in contact with the outer surface 13a of the light transmission optical unit 13 is increased, and the light source unit 11 is emitted and reflected. The light reflected by 12a is easily totally reflected by the outer surface 13a. As a result, transmission efficiency can be increased.
In addition, since the outer surface 13a of the optical transmission optical unit 13 is provided with a reflective film, even if the refractive index of the optical transmission optical unit 13 is small, the light emitted from the light source unit 11 and reflected by the reflective surface 12a It becomes easy to reflect on the side surface 13a, and the transmission efficiency can be improved.
In addition, the light source unit 11 has a reflecting surface 13a of the light transmission optical unit 13 in a virtual plane including the emission optical axis of the light source unit 11 and the center O1 of a circular arc that forms a cylindrical shape on the outer surface 13a of the light transmission optical unit 13. The angle α between the virtual straight line perpendicular to the emission optical axis of the light and the reflection optical axis of the reflection surface 12a is 90 ° ± 20 °, and the normal of the reflection surface 12a and the emission optical axis of the light source unit 11 Therefore, the illumination light can be transmitted while maintaining good transmission efficiency via the outer surface 13a of the optical transmission optical unit 13.

Second Embodiment FIG. 2 is an explanatory diagram showing the configuration of the main part of an endoscope side illumination optical system according to a second embodiment of the present invention. FIG. 2 (a) shows the endoscope side illumination optical system on the light source side. Front view, (b) is a side view of (a), (c) is a view of (a) from above, (d) is a view of the endoscope side illumination optical system from the end of the endoscope It is a perspective view.
In the endoscope side illumination optical system 10 ′ of the present embodiment, the light transmission optical unit 13 ′ is formed on a cylindrical surface in which the outer surface 13a and the inner surface 13b are located on a concentric circle with the axis O1 as the center, The wall thickness is substantially the same as the diameter of the exit opening of the light source section 11 (the exit end 11a1 of the light guide 11a), and the exit opening of the light source section 11 is disposed at a position close to the outer surface 13a. .
Other configurations are substantially the same as those of the endoscope side-view illumination optical system of the first embodiment.

According to the endoscope side illumination optical system 10 ′ of the present embodiment, since the exit opening of the light source unit 1 is disposed at a position close to the outer surface 13a of the light transmission optical unit 13 ′, the side-view observation optical system 20 is arranged. In addition to ensuring a large space in the inner region for placement, the light reflected by the reflecting surface 12a is easily totally reflected over the entire range of the outer surface 13a, and transmission efficiency can be further improved.
Other functions and effects are substantially the same as those of the endoscope side illumination optical system 10 of the first embodiment.

Third Embodiment FIG. 3 is an explanatory view showing the configuration of the main part of an endoscope side illumination optical system according to a third embodiment of the present invention. FIG. 3 (a) shows the endoscope side illumination optical system on the light source side. Front view, (b) is a side view of (a), (c) is a view of (a) from above, (d) is a view of the endoscope side illumination optical system from the end of the endoscope It is a perspective view.
In the endoscope side illumination optical system 10 ″ of the present embodiment, the light transmission optical unit 13 ″ is centered on the first axis O1 ₁ and the second axis O1 ₂ that are different in the outer surface 13a and the inner surface 13b, respectively. Are formed on a cylindrical surface having non-concentric radii R1 and R2, and the thickness decreases from a portion facing the reflecting surface 12a toward the exit surface 13c. Arc of the inner surface 13b is kept at an angle of 180 degrees a second axis O1 ₂ as the center.
The optical member 14 comprises a scattering surface 14a, compared to the first and second embodiments, the thickness from the incident surface 14 ₁ a to the exit surface 14 ₂ a is larger. In addition, a reflective film is provided on the side surfaces around the entrance surface 14 ₁ a and the exit surface 14 ₂ a.
Other configurations are substantially the same as those of the endoscope side illumination optical system according to the first embodiment.

According to the endoscope side illumination optical system 10 ″ of the present embodiment, the optical member disposed on the outer periphery of the side-view observation optical system 20 while ensuring a space in the inner region where the side-view observation optical system 20 is disposed. Since the outer diameter can be made as small as possible, a narrower space can be observed, and the radius of curvature of the arc of the outer surface 13a can be increased if the overall compactness is not achieved. The light reflected by the surface 12a is easily totally reflected by the outer surface 13a over the entire range, and the transmission efficiency can be further improved.
Other functions and effects are substantially the same as those of the endoscope side illumination optical system according to the first embodiment.

As shown in FIG. 4, the endoscope side illumination optical system according to each of the above embodiments configured as described above has an endoscope whose tip is integrated with the main body, and whose endoscope tip is The present invention can be applied to any endoscope that can be attached to and detached from the main body.
FIG. 4 is an explanatory view showing the appearance of the distal end portion of the endoscope using the endoscope side illumination optical system according to each of the embodiments of the present invention. FIG. 4A is a view showing that the distal end portion is integrally formed with the main body portion. The figure which shows the example used for the type of side-view type endoscope which was used, (b) is the example used for the endoscope front-end part of the type where the tip part was configured to be detachable from the endoscope body part FIG. In FIG. 4, 1 is a side-view endoscope, 1a is a side-view endoscope tip, 1a1 is a side-view endoscope tip, 1a2 is a front-view endoscope tip, and 1b is an endoscope. The mirror main body, 20 ′ is a front observation observation optical system, and 21 ′ is a front observation illumination optical system.

As described above, the endoscope side illumination optical system according to the embodiment of the present invention has been described. In the endoscope side illumination optical system according to each embodiment, the light transmission optical unit is illustrated in FIGS. Such a cross-section is not limited to a U-shape, and for example, a cross-section formed in a J-shape may be used. In that case, the reflection surface 12a may be configured to reflect light from the light source unit 11 to one side.
In the endoscope side illumination optical system of each of the above-described embodiments shown in FIGS. 1 to 3, air is in contact with the outer surface 13a of the light transmission optical unit 13 (13 ′, 13 ″). The side surface 13a may be fixed to the endoscope distal end housing with an adhesive. In that case, the refractive index of the optical transmission optical unit 13 (13 ′, 13 ″) and the refractive index of the adhesive When the conditional expression (3) cannot be satisfied, a reflection film may be provided on the outer surface 13a of the optical transmission optical unit 13 (13 ′, 13 ″). Although the surface 12a is provided on each surface constituting the wedge surface of the V-shaped wedge-shaped portion 12, it may be provided directly without interposing the wedge-shaped portion.
Further, the wedge-shaped part 12 having the reflecting surface 12a and the optical transmission optical part 13 (13 ′, 13 ″) may be integrally molded or joined to each other.
In the endoscope side illumination optical system of each of the above embodiments, the exit end 13c of the light transmission optical unit 13 (13 ′, 13 ″) is formed in an elongated shape along the longitudinal direction of the endoscope. For example, it may be formed in a rectangular shape having a certain width.
In addition, the use of the endoscope side illumination optical system of the present invention is not limited to an industrial side endoscope, and may be used, for example, for a medical side endoscope. .

  The endoscope side illumination optical system according to the present invention is useful in, for example, all fields in which it is required to observe an observation object positioned laterally in a narrow observation space.

DESCRIPTION OF SYMBOLS 1 Side view type | mold endoscope 1a Side view type | mold endoscope front-end | tip part 1a1 Side view endoscope front end part 1a2 Front view endoscope end part 1b Endoscope main body part 10, 10 ', 10 "Endoscope Side illumination optical system 11a Light guide 11a1 Ejection end 12 V-shaped wedge-shaped portion 12a Reflected surfaces 13, 13 ', 13 "Light transmission optical unit 13a Outer side surface 13b Inner side surface 13c Ejection ends 14, 14 ₁ , 14 _second optical member 14a scattering surface 14 ₁ a incident surface 14 ₂ a exit plane 20 side view observation optical system 20 'for observation front observation optical system 21 objective lens 21a incident surface (observation window)
21 'Front observation illumination optical system 22 Deflection member 51 Side illumination optical system 51a Light emitter 51a1 Light guide 51b Illumination lens 52 Side observation optical system 52a Objective lens 61 Side illumination optical system 61a Light guide fiber bundle 61b Illumination range conversion Part 61b1 Reflecting plate 61b11 First reflecting surface 61b12 Second reflecting surface 61b2 Conversion unit main body 61b21 Opening 62 Side viewing optical system 62a Observation window 62b Prism 71 Side illumination optical system 71a Light guide 71b Optical element 71b1 Incident surface 71b2 Reflecting surface 71b3 Exit surface 72 Side-view observation optical system 72a Prism 72b Objective lens 73 Image guide 71 'Side illumination optical system 71a' Light guide 71b 'Optical element 71b1' Incidence surface 71b2 'Reflection surface 72' Side-view observation optical system 72a 'Prism 72b 'Objective Lens 73' Image Guide 1 endoscope tip portion 82 within the endoscope body portion 83 side view observation optical system 83a objective lens 83b prism 83b1 reflecting surfaces 83c, 83d lens 83e imaging device 84 side view observation optical system 84a light guide 84a1 exit end 84b illumination lens

Claims (7)

Illuminating an observation object positioned laterally of the endoscope distal end in an endoscope provided with a side-view observation optical system having an observation window for taking in light from the observation object positioned laterally of the endoscope distal end A side illumination optical system,
A light source unit having an exit opening facing the distal end side of the endoscope;
A reflecting surface that reflects the illumination light emitted from the exit opening of the light source section to the side;
Located on the outer periphery of the side-view observation optical system, the cross section is formed in a substantially U shape or a substantially J shape, and the outer surface is formed in a cylindrical shape centering on a predetermined axis along the longitudinal direction of the endoscope. And an optical transmission optical unit that guides the illumination light reflected by the reflecting surface toward the observation target side positioned on the side of the endoscope distal end,
End illumination of the endoscope, wherein an exit end of the optical transmission optical unit is formed in an elongated shape along a longitudinal direction of the endoscope and is disposed on a side of the observation window. Optical system.   The endoscope side illumination optical system according to claim 1, further comprising a scattering surface in the vicinity of the exit end of the light transmission optical unit. The endoscope side illumination optical system according to claim 1, wherein the following conditional expression is satisfied.
1.45 <n _IN
Here, n _IN is the refractive index of the optical transmission optical unit. The endoscope side illumination optical system according to claim 1, wherein the following conditional expression is satisfied.
0.4 <r / R
Here, R is a radius of a circular arc having a cylindrical shape on the outer surface of the optical transmission optical unit, and r is a distance from the center of the circular arc to the center of the emission opening of the light source unit. The endoscope side illumination optical system according to any one of claims 1 to 4, wherein the following conditional expression is satisfied.
1.4 <n _IN / n _OUT
Here, n _IN is a refractive index of the optical transmission optical unit, and n _OUT is a refractive index of a substance in contact with the outer surface of the optical transmission optical unit.   The endoscope side illumination optical system according to any one of claims 1 to 5, wherein a reflection film is provided on the outer surface of the light transmission optical unit.   The reflection surface is a virtual straight line perpendicular to the emission optical axis in a virtual plane including an emission optical axis of the light source unit and a center of a circular arc forming a cylindrical shape on the outer surface of the light transmission optical unit; The angle formed by the reflection optical axis of the reflection surface is 90 ° ± 20 °, and the angle formed by the normal line of the reflection surface and the emission optical axis of the light source unit is 45 ° ± 20 °. The endoscope side illumination optical system according to claim 1, wherein the endoscope side illumination optical system is disposed.

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