JP2022028601A - Illumination optical system for endoscope, optical adapter for endoscope, and optical element - Google Patents

Abstract

To provide an illumination optical system for endoscope that can diffuse illumination light only in a predetermined direction with less light distribution unevenness without reducing a light amount of the illumination light in a visual field.SOLUTION: A light transmission optical member 51 for endoscope includes: an incident surface 51c provided at a distal end portion 11 of an insertion section 5, on which light is made incident as incident light from a proximal end side of the insertion section 5; and emission surfaces 51a and 51b for emitting the light as illumination light. The emission surfaces 51a and 51b each include a diffusing section DS which diffuses the emitted light. The diffusing section DS includes a plurality of convex-shaped sections UF extending in a predetermined direction OC on the emission surfaces 51a and 51b. Each of the convex-shaped sections UF includes: a slope section IP1 having an angle θa with respect to the emission surfaces 51a and 51b, and totally reflecting the incident light; and a slope section IP2 having an angle θb smaller than the angle θa with respect to the emission surfaces 51a and 51b and transmitting and emitting reflected light totally reflected on the slope section IP1 and the incident light.SELECTED DRAWING: Figure 15

Description

The present invention relates to an illumination optical system for an endoscope, an optical adapter for an endoscope, and an optical element, and more particularly to an illumination optical system for an endoscope that diffuses emitted light, an optical adapter for an endoscope, and an optical element.

Endoscopes are widely used in the industrial and medical fields. The endoscope has an insertion portion and emits illumination light from the tip of the insertion portion. The reflected light of the illumination light from the subject is received by the observation window, and the subject image in the subject is obtained by acquiring the subject image.

Endoscopes include endoscopes for direct vision and endoscopes for lateral vision. In order to uniformly irradiate the subject with the illumination light, a diffusion element having a diffusion surface for diffusing the light is often provided in the illumination optical system.

For example, Japanese Patent Application Laid-Open No. 2019-69043 uses a U-shaped prism to reduce the amount of light leaking to the outside without total internal reflection, and to improve the transmission efficiency of illumination light. Illumination optics have been proposed. In the endoscope according to the proposal, a diffusion element having a diffusion surface is provided in order to evenly diffuse the illumination light emitted from the U-shaped prism in all directions, that is, in the two-dimensional direction.

JP-A-2019-69043

However, if a diffuser element that diffuses the light evenly in the two-dimensional direction is used, the illumination light is diffused outside the field of view of the endoscopic image displayed on the monitor, for example, and the amount of light in the field of light is reduced. There is a problem that it will end up.

For example, the above-mentioned U-shaped prism has a reflecting surface inclined so as to direct light toward the emitting surface side. Since the light distribution of the illumination light reflected by the reflecting surface is not isotropic, if the diffusion element is arranged on the emission side of the U-shaped prism, the total amount of light in the visual field is reduced.

Further, in order to diffuse the light in the one-dimensional direction corresponding to the horizontal direction of the screen according to the shape of the horizontally long monitor screen on which the endoscopic image is displayed, a diffusion element having an uneven surface having a triangular cross-sectional shape, for example, is used. It can also be provided on the emission surface side of the illumination light. However, simply adopting a diffusing element having a concavo-convex surface having a triangular cross-sectional shape has a problem that the amount of return light reflected by the concavo-convex surface of the diffusing element increases and the amount of light decreases.

FIG. 27 is a diagram for explaining a decrease in the amount of light in a diffusion element having an uneven surface having a trapezoidal cross-sectional shape. FIG. 27 shows a partial cross section of the uneven surface. As shown in FIG. 27, the incident light R1 shown by the alternate long and short dash line is refracted on the slope of the uneven surface of the diffuser element DE and emitted as the emitted light R1E. It is totally reflected on the uneven surface of the surface and becomes the return light R2E.

Therefore, the present invention presents an illumination optical system for an endoscope, an optical adapter for an endoscope, and an optical system capable of diffusing only in a predetermined direction with a small amount of light distribution unevenness without reducing the amount of illumination light in the visual field. It is intended to provide an element.

The illumination optical system for an endoscope according to one aspect of the present invention is an illumination optical system for an endoscope having an insertion portion to be inserted into a subject, and is provided at the tip of the insertion portion and has the insertion portion. It has an optical element having an incident surface on which light is incident as incident light from the proximal end side of the The diffuser portion has a plurality of convex portions extending along a predetermined direction on the emission surface, and each convex portion has a first angle with respect to the emission surface and the incident light. The total reflection surface has a second angle smaller than the first angle with respect to the emission surface, and the reflected light totally reflected by the total reflection surface and the incident light are transmitted and emitted. It has a transparent surface and a transparent surface.

The optical adapter for an endoscope according to one aspect of the present invention is an optical adapter that can be attached to the tip of an insertion portion of an endoscope having an insertion portion to be inserted into a subject, and is provided at the tip. An optical element having an incident surface on which light is incident as incident light from the proximal end side of the insertion portion, an emitting surface for emitting the light as illumination light, and the illumination light from the emitting surface of the optical element. It has an illuminating window that emits light, the emitting surface has a diffusing portion that diffuses the emitted light, and the diffusing portion has a plurality of convex portions extending along a predetermined direction on the emitting surface. Each convex portion has a first angle with respect to the emission surface and a total reflection surface that totally reflects the incident light, and a second surface smaller than the first angle with respect to the emission surface. It has an angle of the above and has a reflected light that is totally reflected by the total reflecting surface and a transmitting surface that transmits and emits the incident light.

The optical element according to one aspect of the present invention is an optical element having an incident surface on which light is incident as incident light from the proximal end side and an emitting surface on which the light is emitted as emitted light. It has a diffusing portion that diffuses the emitted light, the diffusing portion has a plurality of convex portions extending along a predetermined direction on the emitting surface, and each convex portion has a position with respect to the emitting surface. A total reflection surface having an angle of 1 and totally reflecting the incident light, and a second angle having a second angle smaller than the first angle with respect to the emission surface and being totally reflected by the total reflection surface. It also has a transmission surface that transmits and emits the incident light.

According to the present invention, an illumination optical system for an endoscope, an optical adapter for an endoscope, and an optical system capable of diffusing only in a predetermined direction with a small amount of light distribution unevenness without reducing the amount of illumination light in the visual field. The element can be realized.

It is a block diagram which shows the structure of the endoscope apparatus which concerns on 1st Embodiment of this invention. It is a perspective view of the optical adapter which concerns on 1st Embodiment of this invention. It is a top view of the optical adapter seen from the subject side which concerns on 1st Embodiment of this invention. It is sectional drawing of the optical adapter along the IV-IV line of FIG. It is sectional drawing of the optical adapter along the VV line of FIG. It is sectional drawing of the optical adapter along the VI-VI line of FIG. It is a perspective view of the image pickup optical system and the illumination optical system in the optical adapter which concerns on 1st Embodiment of this invention. It is a front view of the image pickup optical system and the illumination optical system in the optical adapter which concerns on 1st Embodiment of this invention. It is a right side view of the image pickup optical system and the illumination optical system in the optical adapter which concerns on 1st Embodiment of this invention. It is a perspective view of the optical transmission optical member which concerns on 1st Embodiment of this invention. It is a perspective view of one of the two extension portions of the optical transmission optical member according to the first embodiment of the present invention. It is a perspective view of the diffusion part of each extension part of the optical transmission optical member which concerns on 1st Embodiment of this invention, and the optical member arranged above the diffusion surface. It is a side view of the diffusion part of each extension part of the optical transmission optical member which concerns on 1st Embodiment of this invention, and two optical members arranged above the diffusion surface. It is an enlarged side view of the diffusion part of each extension part of the optical transmission optical member which concerns on 1st Embodiment of this invention, and a part of the optical member arranged above the diffusion surface. It is sectional drawing which shows the shape of the cross section of the plurality of convex portions which concerns on 1st Embodiment of this invention. It is sectional drawing of the triangular prism member of the smallest unit which defines the shape of the two slopes of each convex part which concerns on 1st Embodiment of this invention. It is a figure for demonstrating the cross-sectional shape of each convex part which concerns on 1st Embodiment of this invention. It is a figure for demonstrating the optical path in the diffusion part which concerns on 1st Embodiment of this invention. It is a figure which shows the light distribution of the illumination light when the angle θa of a convex part is 75 degrees, and the angle θb is 20 degrees by the simulation performed by the applicant which concerns on the 1st Embodiment of this invention. It is a figure which shows the light distribution of the illumination light when the angle θa of a convex part is 80 degrees, and the angle θb is 20 degrees by the simulation performed by the applicant which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the shape of the cross section of the diffusion part which has a plurality of convex parts which concerns on the 1st Embodiment 1 of this invention. It is sectional drawing which shows the shape of the cross section of the diffusion part which has a plurality of convex parts which concerns on the 1st Embodiment 2 of this invention. It is sectional drawing which shows the shape of the cross section of the diffusion part which has a plurality of convex parts which concerns on the 1st Embodiment 4 of this invention. It is a perspective view of the tip part of the endoscope which concerns on the 2nd Embodiment of this invention. It is a top view which shows the arrangement of two optical elements and a rod lens in the tip part which concerns on 2nd Embodiment of this invention. It is a top view which shows the arrangement of two optical elements and a rod lens in the tip part which concerns on the modification 4 of the 2nd Embodiment of this invention. It is a figure for demonstrating the decrease in the amount of light in the diffusion element which has a concave-convex surface having a trapezoidal cross-sectional shape.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First Embodiment)
(Configuration of endoscope device)

FIG. 1 is a configuration diagram showing a configuration of an endoscope device according to the present embodiment.

As shown in FIG. 1, the endoscope device 1 includes a device main body 2 having a function such as a video processor and an endoscope 3 connected to the device main body 2. The apparatus main body 2 has a display unit 4 such as a liquid crystal panel (LCD) on which an endoscope image, an operation menu, and the like are displayed. The display unit 4 may be provided with a touch panel.

The endoscope 3 has an insertion unit 5 as an endoscope insertion unit inserted into a subject, an operation unit 6 connected to the base end of the insertion unit 5, and a universal cord extending from the operation unit 6. It is configured to have 7. The endoscope 3 can be attached to and detached from the apparatus main body 2 via the universal cord 7.

The insertion portion 5 is configured to include a tip portion 11, a curved portion 12, and a long flexible portion 13 in order from the tip side. The curved portion 12 is continuously provided at the base end of the tip portion 11, and is configured to be bendable in the vertical and horizontal directions, for example. The flexible portion 13 is connected to the curved portion 12 at the base end and has flexibility.

An image pickup element 11x (FIG. 4) such as a CMOS image sensor is built in the tip portion 11 of the insertion portion 5. The image pickup device 11x receives incident light incident on an observation window (not shown) provided at the tip end portion 11 of the insertion portion 5.

As shown by the arrow, the optical adapter 10 for lateral viewing can be detachably attached to the tip portion 11. By attaching the optical adapter 10 for side view to the tip portion 11, the endoscope 3 becomes a side view endoscope. That is, the optical adapter 10 can be attached to the tip portion 11 of the insertion portion 5 of the endoscope 3.

The operation unit 6 is provided with a curved joystick 6a that curves the curved portion 12 in the vertical and horizontal directions. The user can bend the curved portion 12 in a desired direction by tilting the curved joystick 6a. Further, in addition to the curved joystick 6a, the operation unit 6 is provided with buttons for instructing the endoscope function, for example, various operation buttons such as a freeze button, a curved lock button, and a recording instruction button.

When the display unit 4 is provided with a touch panel, the user may operate the touch panel to instruct various operations of the endoscope device 1.

The display unit 4 of the apparatus main body 2 displays an endoscopic image captured by the image pickup element 11x (FIG. 4) of the image pickup unit provided in the tip end portion 11. Further, inside the apparatus main body 2, various circuits such as a control unit (not shown) for performing image processing and various controls, a recording device for recording processed images in a memory (not shown), and the like are provided.
(Optical adapter configuration)

FIG. 2 is a perspective view of the optical adapter 10. FIG. 3 is a plan view of the optical adapter 10 as seen from the subject. FIG. 4 is a cross-sectional view of the optical adapter 10 along the IV-IV line of FIG. FIG. 5 is a cross-sectional view of the optical adapter 10 along the VV line of FIG. FIG. 6 is a cross-sectional view of the optical adapter 10 along the VI-VI line of FIG. FIG. 7 is a perspective view of the imaging optical system and the illumination optical system in the optical adapter 10. FIG. 8 is a front view of the imaging optical system and the illumination optical system in the optical adapter 10. FIG. 9 is a right side view of the imaging optical system and the illumination optical system in the optical adapter 10.

As shown by the alternate long and short dash line in FIG. 4, the tip portion 11 of the insertion portion 5 has a tip rigid member 11a having a cylindrical shape, and a male screw is formed in a part region R1 of the outer peripheral surface of the tip rigid member 11a. The portion 11b is formed.

The side-view optical adapter 10 has a cylindrical shape, and has a cylindrical stop ring 10a on the proximal end side. The stop ring 10a is rotatable around the central axis of the insertion portion 5 (here, the central axis of the tip portion 11) O (hereinafter referred to as the axis O), and is formed on the inner peripheral surface of the base end portion of the stop ring 10a. Is formed with a female screw portion 10b that can be screwed into the male screw portion 11b. The axis O coincides with the central axis of the cylindrical optical adapter 10 when the optical adapter 10 is attached to the tip portion 11.

The tip rigid member 11a is inserted inside the stop ring 10a, and the stop ring 10a is rotated in a predetermined direction to screw the male screw portion 11b and the female screw portion 10b, whereby the optical adapter 10 is attached to the tip portion 11. Can be attached and fixed. When the stop ring 10a is rotated in a predetermined direction, the inward flange portion 10c provided at the tip of the stop ring 10a presses the stepped portion of the adapter body 31 of the optical adapter 10. As a result, the optical adapter 10 is firmly fixed to the tip portion 11.

Further, the optical adapter 10 can be removed from the tip portion 11 by rotating the stop ring 10a in a direction opposite to a predetermined direction.

As shown in FIGS. 2 and 3, on the side surface of the optical adapter 10 on the distal end side, an observation window 22 for lateral viewing and two illumination windows 23a and 23b provided so as to sandwich the observation window 22 are arranged. Has been done.

As shown in FIG. 3, the observation window 22 has a partial circular shape having two straight line portions 22a cut on both sides along the axis O direction when viewed face-to-face. Two illumination windows 23a and 23b are arranged adjacent to the two straight lines 22a of the observation window 22. The observation window 22 takes in light from the side of the tip portion 11 of the insertion portion 5.

Each of the illumination windows 23a and 23b has an elongated shape extending parallel to the axis O when viewed face-to-face, and is a substantially quadrangle with chamfered corners at the four corners of the rectangle as shown in FIG.

As shown in FIG. 4, the cover member 32 is fixed to the adapter main body 31 so as to cover the tip surface of the adapter main body 31 of the optical adapter 10. The cover member 32 has a cylindrical shape with the tip side closed. The cylindrical adapter body 31 is arranged so as to fit inside the cylindrical member 33. The cylindrical member 33 is fixed to the adapter main body 31 by a fixing means such as a screw (not shown). The cylindrical member 33 is arranged so as to fit inside the cylindrical cover member 32. The cover member 32 is fixed to the cylindrical member 33 by a fixing means such as a screw (not shown).

The cover member 32 and the cylindrical member 33 each have openings 32a and 33a formed by being cut off along the axis O direction so as to pass a position separated from the axis O by a predetermined distance in the outer diameter direction. ing. The observation window 22 and the two illumination windows 23a and 23b are arranged in the two openings 32a and 33a formed in the cover member 32 and the cylindrical member 33.

In the observation window 22, the plano-concave lens 41 is positioned by the positioning portion 42 and fixed to the adapter main body 31, the cover member 32, and the cylindrical member 33 with an adhesive. The front surface of the plano-concave lens 41 is a flat surface, and the back surface is a concave surface. The positioning portion 42 is formed by a part of the adapter main body 31.

A prism portion 43 composed of two prisms 43a and 43b is arranged on the back surface of the plano-concave lens 41.

The adapter body 31 is formed with a hole 31a having a cylindrical shape parallel to the axis O. A lens portion 44 composed of two lenses 44a and 44b arranged along the central axis O1 of the hole 31a is disposed on the proximal end side of the prism portion 43, and is fixed in the hole 31a of the adapter main body 31 with an adhesive. ing. The cover glass 45 is arranged on the base end side of the lens portion 44, and is fixed in the hole 31a of the adapter main body 31 with an adhesive.

The joint surface of the two prisms 43a and 43b constitutes a reflective surface that reflects the light from the plano-concave lens 41 toward the lens portion 44. This reflective surface can be formed of a metal film or a multilayer film. Specifically, the reflective surface can be formed by coating with a metal such as aluminum. Further, the reflective surface may be configured so that the total reflected light is simply directed to the lens portion 44 without any treatment such as coating. Therefore, the prism portion 43 is fixed to the adapter main body 31 with an adhesive so that the traveling direction of the light from the plano-concave lens 41 is changed by 90 degrees and emitted toward the lens portion 44. The plano-concave lens 41, the prism portion 43, the lens portion 44, the cover glass 45, and the lens group in the tip portion 11 (not shown) constitute the observation optical system of the endoscope 3. The optical axes of the prism portion 43 and the lens portion 44 do not coincide with the axis O.

As described above, the plano-concave lens 41, the prism portion 43, the lens portion 44, and the cover glass 45 of the optical adapter 10 receive the light taken in from the observation window 22 from the tip side to the base end side along the longitudinal axis of the tip portion 11. It constitutes an observation optical system that emits light toward. The brightness diaphragm 47 is arranged on the base end side of the prism portion 43.

As shown in FIGS. 6 to 9, in the illumination window 23a, two optical members 23a1 and 23a2 stacked in a direction orthogonal to the axis O are positioned by a positioning portion 42, and an adapter main body 31 and a cover are provided by an adhesive. It is fixed to the member 32 and the cylindrical member 33. The two optical members 23a1 and 23a2 are bonded together with an optical adhesive. As the optical adhesive, for example, a resin adhesive of a type that is cured by exposing it to ultraviolet rays may be used.

Similarly to the illumination window 23a, the two optical members 23b1 and 23b2 stacked in the direction orthogonal to the axis O are positioned by the positioning portion 42 in the illumination window 23b, and the adapter main body 31, the cover member 32 and the cover member 32 are formed by the adhesive. It is fixed to the cylindrical member 33. The two optical members 23b1 and 23b2 are bonded together with an optical adhesive. The illumination windows 23a and 23b emit illumination light to the side of the tip portion 11.

The optical members 23a1 and 23b1 are elongated and plate-shaped glass members. The optical members 23a2 and 23b2 have a diffusion surface (shown by a dotted line in FIGS. 6, 8 and 9) which is a grain surface processed into a ground glass shape on the surfaces on the optical members 23a1 and 23b1 sides, respectively. There is. Light is diffused isotropically (randomly) on the diffusion surface, which is a grain surface. This makes it possible to further eliminate the uneven light distribution. The optical members 23a2 and 23b2 are adhered to the optical members 23a1 and 23b1 on the diffusion surface side with an optical adhesive having a refractive index different from that of the optical members 23a1 and 23b1 and the optical members 23a2 and 23b2, respectively. Light is scattered at.

It should be noted that the grain surface of the glass member has a large difference in refractive index and too large diffusivity on the contact surface with air, so that the light distribution spreads too much. For this reason, in order to reduce the diffusion angle of the grain to the extent of spotting, the glass members are joined to each other with an optical adhesive having a refractive index of 1.52 or 1.56 (in this example). , The refractive index of glass is 1.8).

Furthermore, if the above-mentioned grain surface and the later-described diffusion structure are exposed to the air, the grain surface and the like may be scratched when the endoscope 3 is used, or droplets may adhere to the optical characteristics. Since it changes, it is possible to prevent scratches and the like by providing the optical members 23a1 and 23b1 as a cover glass.

Since the surfaces of the openings 32a and 33a of the cover member 32 and the cylindrical member 33, the plano-concave lens 41 and the two optical members 23a1 and 23b1 are flat surfaces, the optical adapter 10 has a shaft formed by these planes. It has a flat surface portion 10p parallel to O.

The illumination light is emitted from the illumination windows 23a and 23b in the direction LD (hereinafter referred to as the illumination direction LD) orthogonal to the axis O.

The adapter body 31 is formed with a hole 31b for the rod lens 46 along the axis O direction. The center of the hole 31b does not coincide with the shaft O, and the hole 31b is formed in the adapter main body 31 so as to be displaced in the outer diameter direction from the shaft O. The rod lens 46 is inserted into the hole 31b and fixed to the adapter main body 31 with an adhesive or the like. Therefore, the cross-sectional shape of the hole 31b substantially matches the outer diameter shape of the rod lens 46. As shown in FIG. 5, the cross-sectional shape of the rod lens 46 orthogonal to the axis O is flat, the surface 46a on the axis O side is a flat surface, and the surface 46b on the outer diameter direction side is in the outer diameter direction. It has a protruding partial cylindrical shape.

As shown in FIG. 4, a light guide 11y for illumination light is inserted in the insertion portion 5. The front end surface of the light guide 11y is arranged so as to face the back surface of the illumination window (not shown) of the tip end portion 11. When the optical adapter 10 is attached to the tip portion 11, the rod lens 46 is placed in the optical adapter 10 so that the illumination window (not shown) of the tip portion 11 faces the proximal end surface of the rod lens 46. It is arranged in.

An optical transmission optical member 51 is disposed on the tip end side of the tip end surface of the rod lens 46, and is fixed to the adapter main body 31 with an adhesive or the like.

The illumination windows 23a and 23b, the optical transmission optical member 51, and the rod lens 46 constitute an endoscope illumination optical system for the endoscope 3 having an insertion portion 5 inserted into the subject.

As shown in FIG. 7, the light L1 from the subject is incident on the observation window 22 from the side of the optical adapter 10. The light L1 is incident on the plano-concave lens 41, reflected by the prism portion 43, passes through the lens portion 44 and the cover glass 45, and is emitted toward the image pickup optical system of the tip portion 11.

The light L2 emitted from the tip surface of the light guide 11y of the tip portion 11 is incident on the proximal end surface of the rod lens 46, and is incident on the incident surface which is the proximal end surface of the optical transmission optical member 51 from the distal end surface of the rod lens 46. , Is emitted from the exit surface of the optical transmission optical member 51, and is emitted from the two illumination windows 23a and 23b to the side of the optical adapter 10.
(Structure of Optical Transmission Optical Member 51)

Next, the configuration of the optical transmission optical member 51 of the illumination optical system will be described.

FIG. 10 is a perspective view of the optical transmission optical member 51. FIG. 11 is a perspective view of one of the two extension portions of the optical transmission optical member 51. The configuration and operation of the optical transmission optical member 51 of the present embodiment are substantially the same as the configuration disclosed in Japanese Patent Application Laid-Open No. 2019-69043. Only the different configurations will be briefly described.

As shown in FIG. 9, the optical transmission optical member 51 is an optical member made of transparent glass or plastic having a substantially U-shape when viewed from the axis O direction of the optical adapter 10.

The optical transmission optical member 51 has a partial cylindrical portion 51X and two extending portions 51A and 51B extending from both ends in the circumferential direction of the partial cylindrical portion 51X. The above-mentioned prism portion 43 is arranged in a substantially U-shaped optical transmission optical member 51 so as to be surrounded by the partial cylindrical portion 51X and the two extending portions 51A and 51B.

That is, the optical transmission optical member 51 is formed so that the observation optical system is arranged inside the optical transmission optical member 51 so that the cross-sectional shape seen from the tip end side of the longitudinal axis is a substantially U-shape or a part of the substantially U-shape. It is a prism.

An exit surface 51a is formed on the end surface of the extension portion 51A, and an exit surface 51b is formed on the end surface of the extension portion 51B. Hereinafter, in the optical transmission optical member 51, the direction in which the exit surfaces 51a and 51b of the extending portions 51A and 51B are present is also referred to as an upper direction.

Each of the emission surfaces 51a and 51b is provided with a diffusion unit DS for diffusing light in a predetermined direction (in the present embodiment, in a direction parallel to the axis O). The diffuser DS is formed here using a molding technique. The diffusion portion DS has a plurality of convex portions UF (FIGS. 12 and 13). The plurality of convex portions UF are formed so as to extend along the direction orthogonal to the axis O on the exit surfaces 51a and 51b. The diffuser DS is formed at the same time when the optical transmission optical member 51 is manufactured by molding using a mold. Therefore, the diffuser DS can be formed by molding when the optical transmission optical member 51 is manufactured, so that the workability is good.

A plate-shaped member having a diffusion portion DS may be attached to each of the exit surfaces 51a and 51b with an optical adhesive so that the diffusion portion DS is provided on each of the extension portions 51A and 51B.

A flat surface portion 51a1 is formed on the tip end side of the extension portion 51A, and a flat surface portion 51b1 is formed on the tip end side of the extension portion 51B. Further, a flat surface portion 51c having a substantially U-shape is formed on the base end side of the optical transmission optical member 51. A part of the flat surface portion 51c, that is, a region facing the tip surface of the rod lens 46 is an incident surface of light.

That is, the optical transmission optical member 51 is an illumination optical system and is provided at the tip end portion 11 of the insertion portion 5. The optical transmission optical member 51 is an optical element having a flat surface portion 51c as an incident surface and exit surfaces 51a and 51b that emit light as illumination light. The flat surface portion 51c is an incident surface on which light is incident on the proximal end side of the tip portion 11 along the longitudinal axis direction of the insertion portion 5. The emission surfaces 51a and 51b emit light as illumination light.

A recess 51U is formed on the tip end side of the partial cylindrical portion 51X. The recess 51U is formed in a substantially V shape when the optical transmission optical member 51 is viewed from the subject to which the illumination light is applied. Two reflective surfaces CS1 and CS2, which are curved surfaces, are formed in the recess 51U of the optical transmission optical member 51.

Two reflective surfaces CS1 and CS2 are provided symmetrically with respect to a plane passing through the central axis of the tip portion 11. The two reflective surfaces CS1 and CS2 are curved surfaces that have been subjected to reflection processing such as aluminum coating. It should be noted that the CS1 and CS2 may be configured so that the total reflected light is simply directed to the emission surfaces 51a and 51b without performing a reflection processing such as coating.

By providing the two reflecting surfaces CS1 and CS2 in the recess 51U, the light reflected by the two reflecting surfaces CS1 and CS2 has an incident angle equal to or higher than the critical angle when it is incident on the outer peripheral surface of the optical transmission optical member 51. Therefore, almost all the light from the light guide is totally reflected and reflected toward the two illumination windows to proceed, so that the light transmission efficiency can be improved.
(Structure of diffuser DS)

Next, the diffuser DS of the light emitted from the substantially U-shaped optical transmission optical member 51 will be described. FIG. 12 is a perspective view of the diffusion portion DS of each extension portion of the optical transmission optical member 51 and the optical member arranged on the upper side of the diffusion surface. FIG. 13 is a side view of the diffusion portion DS of each extension portion of the optical transmission optical member 51 and the two optical members arranged above the diffusion surface. FIG. 14 is an enlarged side view of the diffusion portion DS of each extension portion of the optical transmission optical member 51 and a part of the optical member arranged on the upper side of the diffusion surface.

The optical transmission optical member 51 is made of plastic here and has a refractive index of 1.5. The optical members 23a2 and 23b2 are arranged above the exit surfaces 51a and 51b through the air gap g having a refractive index of 1. The optical members 23a1 and 23b1 are closely fixed to the upper surfaces of the optical members 23a2 and 23b2 by an optical adhesive (not shown), respectively. As shown in FIG. 13, the optical members 23a1 and 23b1 are adhered to the grain surface (shown by the dotted line) of the optical members 23a2 and 23b2 with an optical adhesive (not shown). The optical members 23a1, 23b1, 23a2, and 23b2 are made of glass and have a refractive index of 1.8.

It should be noted that the grain surface of the glass member has a large difference in refractive index and too large diffusivity on the contact surface with air, so that the light distribution spreads too much. For this reason, in order to reduce the diffusion angle of the grain to the extent of spotting, the glass members are joined to each other with an optical adhesive having a refractive index of 1.52 or 1.56 (in this example). , The refractive index of glass is 1.8).

In the optical transmission optical member 51 having a substantially U-shape, the light incident on the flat surface portion 51c is reflected by the two reflecting surfaces CS1 and CS2. The light reflected by the two reflecting surfaces CS1 and CS2, which are curved surfaces, has a characteristic that it is widely diffused in the direction orthogonal to the axis O due to the shape of the reflecting surface, but is not widely diffused in the direction parallel to the axis O. Therefore, in the direction parallel to the axis O, the light is not diffused, so that the light distribution unevenness occurs. Even if a conventional diffuser element that diffuses light isotropically in the two-dimensional direction is used for an optical transmission optical member having such light distribution characteristics, the light distribution unevenness is not improved and the light is emitted by the diffuser element. However, there is a problem that the amount of light in the field of light is reduced because the light is diffused outside the field of view.

Therefore, in the present embodiment, in order to diffuse the light in the direction parallel to the axis O, the light is formed on the emission surfaces 51a and 51b of the extending portions 51A and 51B along the direction orthogonal to the axis O direction. A diffusion portion DS composed of a plurality of convex portions UF is formed. Each diffuser DS diffuses light to the extension 51A and 51B along the axis O direction.

As shown in FIGS. 12 to 14, the diffusion portion DS is formed to have a plurality of convex portions UF formed on the exit surfaces 51a and 51b of the extension portions 51A and 51B. Specifically, the diffusion portion DS has a plurality of convex portions UF extending linearly along a predetermined direction on the exit surfaces 51a and 51b. That is, each convex portion UF is formed so as to extend linearly along the direction OC orthogonal to the axis O on the emission surfaces 51a and 51b. As shown in FIG. 14, each convex portion UF has two slope portions IP1 and two slope portions IP2. Each convex portion UF has two convex portions P1 and P2. As shown in FIG. 14, the slope portion IP1 is a steep slope, and the slope portion IP2 is a gentle slope having a smaller inclination angle than the slope portion IP1.

The two convex portions P1 and P2 of each convex portion UF are also formed so as to extend linearly along the direction OC. The convex portion P1 is formed by one of the two slope portions IP1 and one of the two slope portions IP2, and the convex portion P2 is formed by the other of the two slope portions IP1 and the other of the two slope portions IP2.

The groove G1 is formed by the two slope portions IP1 between the two adjacent convex portions UF. The groove G2 is formed by two sloped portions IP2 that are plane-symmetrical with respect to the plane PP of each convex portion UF. The plurality of grooves G1 and G2 are arranged parallel to each other and alternately.

FIG. 15 is a cross-sectional view showing the shape of the cross section of the plurality of convex portions UF. FIG. 15 shows a cross section of a part of the diffuser DS when the exit surfaces 51a and 51b are viewed from the direction OC. As shown in FIG. 15, the slope portions IP1 and IP2 of each convex portion P1 have angles θa and θb with respect to the virtual plane (that is, the plane parallel to the exit surfaces 51a and 51b) RP parallel to the direction OC, respectively. is doing. The angle θb is smaller than the angle θa.

Further, as described above, the convex portion P2 has a shape symmetrical with respect to the convex portion P1 with respect to the plane PP. Therefore, the slope portions IP1 and IP2 of each convex portion P2 also have angles θa and θb with respect to the virtual plane RP parallel to the direction OC, respectively.

The shape of the convex portion UF will be described in detail. FIG. 16 is a cross-sectional view of a triangular prism member TM having a minimum unit MU that defines the shapes of the two slope portions IP1 and IP2 of each convex portion UF. FIG. 17 is a diagram for explaining the cross-sectional shape of each convex portion UF.

The minimum unit MU has the shape of a triangular prism member TM having a triangular cross section as shown in FIG. Based on the shape of this minimum unit MU, the shapes of the plurality of convex portions P1 and P2 are defined. As shown in FIG. 16, the triangular prism member TM having a triangular cross-sectional shape has a bottom surface portion BS, a slope portion SSa having an angle (internal angle) θa with respect to the bottom surface portion BS, and an angle (internal angle) with respect to the bottom surface portion BS. It has a slope portion SSb having θb. The shape of each convex portion UF is defined based on the shapes of these two slope portions SSa and SSb.

As shown in FIG. 17, when the triangular prism member TM is plane-symmetrical with respect to the plane PP that passes through one point on the slope portion SSb, is parallel to the axis of the triangular prism member TM, and is orthogonal to the bottom surface portion BS. The shapes of the two convex portions P1 and P2 are defined based on the slope portion SSa and the two slope portions SSb. The slope portions IP1 and IP2 forming the convex portions P1 and P2 correspond to a part of the two slope portions SSa and SSb of the triangular prism member TM, respectively.

As shown in FIG. 15, the diffusion portion DS is an uneven portion formed by being arranged on the exit surfaces 51a and 51b. The uneven portion is formed by arranging a plurality of convex portions UF at predetermined intervals d1 along the axial direction parallel to the axis O. Each convex portion UF has two convex portions P1 and P2. The convex portions P1 and P2 are formed by the two slope portions IP1 and IP2. That is, the diffusion portion DS has a shape by a plurality of convex portions UF arranged along the axial direction parallel to the axis O on the exit surfaces 51a and 51b of the extension portions 51A and 51B.

The joint portion JP of the slope portions IP1 and IP2 in each of the convex portions P1 and P2 may not be sharp, and may have, for example, a rounded shape or a chamfered shape cut by multiple faces. ..
(Diffusion and distribution of illumination light)

Next, the diffusion and light distribution of the illumination light will be described.

As shown in FIG. 15, each convex portion UF has two slope portions IP1 and IP2 that are plane symmetric with respect to the plane PP orthogonal to the axis O. The convex portion P1 of each convex portion UF has a shape symmetrical with respect to the plane PP with the convex portion P2. Since each convex portion UF has a shape symmetrical with respect to the flat surface PP, uneven light distribution does not occur in the left-right direction.

FIG. 18 is a diagram for explaining an optical path in the diffuser DS. The light spreads by about 60 ° toward the diffuser DS and is incident. As shown in FIG. 18, a part of the light directed to the diffusion portion DS becomes the light L1 that is totally reflected by the slope portion IP1 of the convex portion P1 and refracted by the slope portion IP2 to be emitted. The other part of the light directed to the diffusing portion DS is incident on the slope portion IP2 of the convex portion P1 and becomes the light L2 that is refracted and emitted at the slope portion IP2.

Further, the other part of the light directed to the diffusion portion DS becomes the light L3 that is totally reflected by the slope portion IP1 of the convex portion P2 and refracted by the slope portion IP2 to be emitted. Still another part of the light directed to the diffusion portion DS becomes the light L4 that is incident on the slope portion IP2 of the convex portion P2 and is refracted and emitted at the slope portion IP2. As a result, the light L1 and L2 and the light L3 and L4 are emitted plane-symmetrically with respect to the plane PP. Since each convex portion UF has two convex portions P1 and P2, the emitted light is emitted with less uneven light distribution. If a diffuser element having a concavo-convex surface having a triangular cross-sectional shape is used, return light is generated as shown in FIG. 27 and the amount of light is reduced. By adopting a structure having IP2 which is a slope, it is possible to emit light without generating return light, and it is possible to prevent a decrease in the amount of light.

As shown in FIG. 15, the depths of the grooves G1 and G2 are Ha and Hb, respectively, and the lengths of the slope portions IP1 and IP2 in the axis O direction when viewed from the direction OC are a and b, respectively. When it is desirable to have the following relationship. Normally, the incident light reaches the diffuser DS with light of about 60 °.

60 ° <θa ≤ 85 ° ・ ・ ・ (1)

0 ° <θb ≦ 30 ° ・ ・ ・ (2)

Ha ≧ Hb ・ ・ ・ (3)

a ≦ b ・ ・ ・ (4)

Equation (1) shows the relationship for totally reflecting the incident light on the slope portion IP1. Equation (2) shows the relationship for transmitting the reflected light from the slope portion IP1 in the slope portion IP2. Equation (3) shows a relationship for transmitting more reflected light from the slope portion IP1. Equation (4) shows the relationship for emitting the reflected light from the slope portion IP1 from the slope portion IP2 with less loss. Equation (4) is a relationship in which the light distribution is adjusted by changing the light amount ratio between the light L1 and L3 having a large exit angle with respect to the plane PP and the light L2 and L4 having a small exit angle with respect to the plane PP. It is also a formula.

That is, when viewed from the direction OC orthogonal to the axis O, the angle θa is an angle in the range of more than 60 ° and 85 ° or less with respect to the emission surfaces 51a and 51b, and the angle θb is the emission surfaces 51a and 51b. The angle is in the range of more than 0 ° and 30 ° or less with respect to the angle.

Further, the depth Ha of the groove G1 formed by the two adjacent slope portions IP1 (total reflection surface) is deeper than the depth Hb of the groove G2 formed by the two adjacent slope portions IP2 (transmission surface). ..

As described above, each convex portion UF has a slope portion IP1 which has an angle θa with respect to the emission surfaces 51a and 51b and is a total reflection surface for totally reflecting the incident light, and a slope portion IP2. The slope portion IP2 has an angle θb smaller than the angle θa with respect to the emission surfaces 51a and 51b, and transmits and emits the reflected light totally reflected by the slope portion IP1 and the incident light directly incident on the slope portion IP2. It becomes a transparent surface.

Each of the convex portions UF is formed by a total reflection surface and a transmission surface so as to be plane symmetric with respect to a surface (PP) orthogonal to the emission surfaces 51a and 51b and parallel to a predetermined direction. It has two convex portions P1 and P2 to be formed.

According to the simulation performed by the applicant, it is a one-dimensional diffuser element having a diffuser DS in which a plurality of isosceles triangles are arranged in a cross-sectional shape, and each slope is 10 degrees or 10 degrees with respect to the bottom surface of the isosceles triangle. In each of the 20-degree diffuser elements, when the light was incident from the direction orthogonal to the bottom surface, sufficient diffusion was not obtained for the illumination light.

Further, according to the simulation performed by the applicant, it is a one-dimensional diffusion element having a diffusion portion DS in which a plurality of isosceles triangles are arranged in a cross-sectional shape, and each slope is 30 with respect to the bottom surface of the isosceles triangle. In each of the diffusion elements of degrees, 40 degrees, 50 degrees, or 60 degrees, when light was incident from a direction orthogonal to the bottom surface, return light was generated by reflection on the diffusion surface, and the amount of light was reduced.

Furthermore, according to the simulation performed by the applicant, it is a one-dimensional diffusion element having a diffusion portion DS in which a plurality of isosceles triangles are arranged in a cross-sectional shape, and each slope is formed with respect to the bottom surface of the isosceles triangle. In each diffusion element of 70 degrees or 80 degrees, when light was incident from a direction orthogonal to the bottom surface, return light due to reflection on the diffusion surface was not generated, but light distribution unevenness occurred.

On the other hand, according to the simulation of the above-described embodiment, when θa is 75 degrees and θb is 20 degrees, the illumination light is diffused in a predetermined direction, and the return light due to the reflection in the diffuser DS is also generated. However, there was little uneven light distribution.

FIG. 19 is a diagram showing the light distribution of the illumination light when the angle θa of the convex portion UF is 75 degrees and the angle θb is 20 degrees according to the simulation performed by the applicant. As shown in FIG. 19, the central region CA is illuminated most brightly, but the peripheral region PA adjacent to the central region CA is also continuously illuminated brightly. Since the illumination range of the illumination light is diffused only in the predetermined direction PO, it is diffused in the predetermined one-dimensional direction (horizontal direction in FIG. 19) PO, and the light distribution unevenness is small. Therefore, for example, the illumination light can be emitted in accordance with the field frame W (indicated by the alternate long and short dash line) of the endoscope image displayed on the monitor.

Further, according to the simulation of the diffusion unit DS of the above-described embodiment, even when the angle θa is 80 degrees and the angle θb is 20 degrees, diffusion can be obtained in a predetermined direction (direction parallel to the axis O). No return light was generated due to reflection in the diffuser DS, and light distribution unevenness was small.

FIG. 20 is a diagram showing the light distribution of the illumination light when the angle θa of the convex portion UF is 80 degrees and the angle θb is 20 degrees according to the simulation performed by the applicant. As shown in FIG. 20, the illumination range of the illumination light is diffused in a predetermined one-dimensional direction (horizontal direction in FIG. 20) PO, and the light distribution unevenness is small.

Therefore, according to the above equations (1) and (2), there is no decrease in the amount of light, and the illumination light can be diffused in a predetermined direction. Further, according to the above equations (3) and (4), uneven light distribution can be reduced.

As described above, according to the above-described embodiment, the illumination optical system for an endoscope and the inside, which can diffuse only in a predetermined direction with a small amount of light distribution unevenness without reducing the amount of illumination light in the field of view. Optical adapters for endoscopes can be provided.

In the above-described embodiment, the endoscope 3 is for side view to observe the inside of the subject by emitting illumination light in a direction orthogonal to the longitudinal axis direction of the insertion portion 5. The form can also be applied to a perspective endoscope that emits illumination light in an oblique direction with respect to the axis O of the insertion portion 5 to observe the inside of the subject.

Next, a modification will be described.
(Modification 1)

In the above-described embodiment, in order to reduce light distribution unevenness, each convex portion UF of the diffuser portion DS has convex portions P1 and P2 that are plane-symmetrical with respect to the plane PP, but the diffuser portion DS has. Each convex portion may have one convex portion and a plurality of the convex portions may be arranged, and the plurality of convex portions may be arranged symmetrically in a plane.

FIG. 21 is a cross-sectional view showing the shape of a cross section of a diffusion portion having a plurality of convex portions UF1 according to the first modification. FIG. 21 shows a cross section of a part of the diffusion portion DS when the emission surfaces 51a and 51b are viewed from the direction OC.

In the first modification, each convex portion UF1 has slope portions IP1 and IP2, and a plurality of convex portions UF1 extend linearly along the direction OC orthogonal to the axis O on the exit surfaces 51a and 51b. It is formed like this. Each convex portion UF1 has one convex portion P3. As shown in FIG. 21, each convex portion P3 is formed by one slope portion IP1 and one slope portion IP2.

Further, half of the plurality of convex portions UF1 are arranged so as to be plane-symmetrical with respect to the plane PP1 orthogonal to the axis O. Half of the plurality of convex portions UF1 are arranged so as to be plane-symmetrical with respect to the plane PP1 of FIG. 21 on the exit surfaces 51a and 51b.

That is, a part of the plurality of convex portions UF1 is plane symmetric with respect to the other part of the plurality of convex portions UF1 with respect to the surface PP1 parallel to the direction OC orthogonal to the axis O, and the emission surface 51a. , 51b.

In this modification 1, the above-mentioned equations (1), (2) and (4) are established, but instead of the above-mentioned equation (3), the following relationship (5) is established.

Ha = Hb ・ ・ ・ (5)

The same effect as that of the above-described embodiment can be obtained by the present modification 1.
(Modification 2)

In the above-mentioned modification 1, in order to reduce the light distribution unevenness, the diffusion portion DS has a plurality of convex portions UF1 that are plane-symmetrical with respect to one plane PP1, but each convex portion is 1. It is also possible to have a plurality of convex portion groups having one convex portion and having a plurality of convex portions arranged in a plane symmetrical manner.

FIG. 22 is a cross-sectional view showing the shape of the cross section of the diffusion portion having the plurality of convex portions UF1 according to the modified example 2. FIG. 22 shows a cross section of a part of the diffusion portion DS when the emission surfaces 51a and 51b are viewed from the direction OC. Each convex portion UF1 of the modified example 2 has the same shape as the convex portion UF1 of the modified example 1.

As shown in FIG. 22, a plurality of (here, two) convex portions UF1 are arranged so as to be plane-symmetrical to each other with respect to the plane PP2 orthogonal to the axis O, and the plurality of plane-symmetrical portions (here) are plane-symmetrical. Then, the diffusion portion DS is formed so that a plurality of convex portion groups Gr1 composed of the convex portions UF1 of 4) are arranged on the exit surfaces 51a and 51b. That is, the diffusion portion DS has a plurality of regions of the convex portion group Gr1.

In other words, a part of the plurality of convex portions UF1 and another part of the plurality of convex portions UF1 are arranged on the exit surfaces 51a and 51b symmetrically with respect to the surface PP2 parallel to the direction OC. There are multiple areas.

In this modification 2, the above-mentioned equations (1), (2) and (4) are also established, but instead of the above-mentioned equation (3), the above-mentioned equation (5) is established.

The same effect as that of the above-described embodiment can be obtained also by the present modification 2.
(Modification 3)

In the above-mentioned example, the convex portion has a portion that is plane-symmetrical to each other on the emission surface with respect to a predetermined plane, but for example, as long as the light distribution on the left and right is not significantly affected. It does not have to have a part that is plane symmetric.

Specifically, the angle of the slope portion IP2 which is a gentle slope may be changed, or the length b may be set to a different value depending on each convex portion. As a result, even if the arrangement of the convex portions is not plane-symmetrical, it is possible to reduce the non-uniformity of the light distribution unevenness on the left and right by appropriately designing the element as a whole. Not only the angle and length of the gentle slope but also the angle and length a of the slope portion IP1 which is a steep slope may be appropriately changed.

Also in the present modification 3, the return light can be reduced and the amount of light can be increased.
(Modification example 4)

In the above-mentioned modifications 1 and 2, the plurality of convex portions have portions arranged in a plane symmetry, but the plurality of convex portions may not be arranged in a plane symmetry.

In the present modification 4, the plurality of convex portions UF1 are arranged so as to be plane-symmetrical with respect to the plane PP1 on the exit surfaces 51a and 51b as shown in FIG. 21 of the above-mentioned modification 1. do not have. Therefore, in the case of the present modification 4, the light distribution direction is biased in one direction.

FIG. 23 is a cross-sectional view showing the shape of the cross section of the diffusion portion having the plurality of convex portions UF1 according to the modified example 4. FIG. 23 shows a cross section of a part of the diffusion portion DS when the emission surfaces 51a and 51b are viewed from the direction OC. Each convex portion UF1 of the modified example 4 has the same shape as one side portion (left portion of FIG. 21) of the plurality of plane-symmetrical convex portions UF1 of the modified example 1.

As shown in FIG. 23, the diffusion portion DS is formed so that a plurality of convex portions UF1 having the same cross-sectional shape are arranged on the exit surfaces 51a and 51b. That is, the slope portions IP1 and IP2 of each convex portion UF1 have the same angle with the slope portions IP1 and IP2 of the other convex portions UF1, respectively, with respect to the virtual plane RP parallel to the direction OC.

In this modification 4, the above-mentioned equations (1), (2) and (4) are also established, but instead of the above-mentioned equation (3), the above-mentioned equation (5) is established.

Therefore, the present modification 4 is effective when, for example, it is desired to bias the light distribution in one direction.

Also in the present modification 4, the return light can be reduced and the amount of light can be increased.

Also in the present modifications 1 to 4, the convex portions P1 and P2, that is, the joint portion JP of the slope portions IP1 and IP2 do not have to be sharp, and have, for example, have a rounded shape or are cut on multiple surfaces. It may have a chamfered shape.
(Second embodiment)

The endoscope device of the first embodiment is an endoscope device for side vision, but the endoscope of the endoscope device of the present embodiment is an insertion portion 5 from an illumination window of a tip portion 11. It is for direct viewing that emits illumination light in front of the tip portion 11 along the longitudinal axis direction of the above.

Since the configuration of the endoscope device of the present embodiment is substantially the same as the configuration of the endoscope device of the first embodiment, in the configuration of the endoscope device of the present embodiment, the first embodiment The same components as those of the endoscope device of the above form will be omitted by using the same reference numerals, and only different configurations will be described.

FIG. 24 is a perspective view of the tip portion 11A of the endoscope 3. The observation window 22x and the illumination window 23x are provided on the tip surface 11Aa of the tip portion 11A. The illumination light is emitted from the illumination window 23x, and the reflected light of the illumination light from the subject is incident on the observation window 22x. The reflected light incident on the observation window 22x is applied to the image pickup surface of the image pickup device 11x via an observation optical system (not shown).

The illumination window 23x has a shape extending in the lateral SD to match the shape of the rectangular endoscope image displayed on the monitor.

A light guide (not shown) that guides the illumination light is inserted in the insertion portion 5. A rod lens 46A having a partially cylindrical shape is provided on the tip end side of the light guide.

FIG. 25 is a plan view showing the arrangement of the two optical members 23A and 23B and the rod lens 46A in the tip portion 11A. FIG. 25 shows the arrangement of the two optical members 23A and 23B and the rod lens 46A when the tip portion 11A is viewed from the upper side of the vertical UD orthogonal to the lateral SD. The incident surface IS of the rod lens 46A and the exit surface on which the diffuser DS is formed are parallel to each other.

For example, the rod lens 46A is made of plastic, has a refractive index of 1.5, and optical members 23A and 23B are arranged via an air gap g having a refractive index of 1. Each of the optical members 23A is in close contact with and fixed to the optical member 23B by an optical adhesive (not shown). The grain surface (shown by the dotted line) side of the optical member 23A is adhered to the optical member 23B by an optical adhesive (not shown). The optical members 23A and 23B are made of glass and have a refractive index of 1.8. Specifically, if the refractive index of the optical adhesive is a value such as 1.52 or 1.56, that is, the refractive index is smaller than that of the optical members 23A and 23B and larger than 1, which is the refractive index of air. good.

A diffusion portion DS having a plurality of convex portions UF is provided on the tip surface of the rod lens 46A. The shape of the convex portion UF of the diffusion portion DS is the same as the shape of the convex portion UF of the first embodiment, but the shape shown in the above-mentioned modification 1 or modification 2 may be used.

That is, the diffusion portion DS has a plurality of convex portions UF extending linearly along a predetermined direction on the exit surface of the rod lens 46A. Since the diffuser DS can be formed by molding when the rod lens 46A is manufactured, the workability is good.

Two optical members 23A and 23B made of glass are arranged on the front end surface side of the rod lens 46A via an air gap g. The optical members 23A and 23B are bonded and fixed by an optical adhesive (not shown). The surface of the optical member 23A on the optical member 23B side is provided with a grain surface (indicated by a dotted line) processed into a frosted glass shape.

Therefore, even with the above-described embodiment, the illumination optical system for an endoscope and the optics for an endoscope can be diffused only in a predetermined direction with a small amount of light distribution unevenness without reducing the amount of illumination light in the field of view. Adapters can be provided.

It is conceivable to provide a diffuser DS on the incident surface IS side of the rod lens 46A, but in that case, when the light passes through the rod lens 46A and is emitted from the exit surface, the light entering the rod lens 46A is emitted. There is a problem that leakage from the side surface of the rod lens 46A causes a decrease in the amount of light emitted from the emitting surface.

Furthermore, in FIGS. 24 and 25, the rod lens 46A as an optical element is arranged in the tip portion 11A of the insertion portion 5, but can be attached to the tip portion 11 of the insertion portion 5 shown in FIG. It may be arranged in the optical adapter 10.
(Modification example)

In the second embodiment described above, the rod lens 46A provided on the tip end side of the light guide has a diffuser DS, but the incident surface on the proximal end side of the rod lens and the tip surface of the light guide. An optical element may be arranged between the two, and the optical element may have a diffuser DS.

FIG. 26 is a plan view showing the arrangement of the two optical elements and the rod lens in the tip portion according to the modified example of the second embodiment. FIG. 26 shows the arrangement of the two optical members 23A and 23B, the rod lens 46B, the optical element 52, and the light guide 11y1 when the tip portion 11A is viewed from the upper side of the vertical UD orthogonal to the lateral SD. The incident surface IS of the rod lens 46B and the exit surface of the optical element 52 (the portion where the diffuser DS is formed) are parallel to each other. Further, the incident surface 52a of the optical element 52 and the tip surface of the light guide 11y1 are also parallel.

As shown in FIG. 26, the optical element 52 is arranged between the front end surface of the light guide 11y1 and the base end surface of the rod lens 46B. The optical element 52 is glass (or plastic) having a flat plate shape. The incident surface 52a of the optical element 52 has a flat surface, and the exit surface of the optical element 52 has a diffuser DS. The diffuser DS has a plurality of convex portions UF extending linearly along a predetermined direction on the emission surface of the optical element 52. As shown in FIG. 26, the convex portion UF has the same shape as the convex portion UF of the diffusion portion DS of the rod lens 46A of FIG. 25 described above.

The light incident on the incident surface 52a of the optical element 52 is diffused and emitted by the diffusing unit DS which is the emitting unit of the optical element 52. The diffused light is internally reflected in the rod lens 46B and travels in various directions, and is emitted so as to spread from the exit surface OS of the rod lens 46B.

The light emitted from the optical element 52 is diffused by the diffuser DS so as to have a spread in the lateral SD (vertical direction in FIG. 26). However, since the rod lens 46B has a partially cylindrical shape, the light from the diffuser DS is internally reflected in the rod lens 46B in various directions other than the lateral SD.

As a result, the light emitted from the exit surface of the rod lens 46B is diffused and emitted not only in the lateral SD but also in various directions, so that the same effect as that of the second embodiment described above can be obtained. can.
(Third embodiment)

The first and second embodiments relate to a substantially U-shaped optical transmission optical member 51 or a rod lens 46A as an optical element used in an endoscope, and have been described in the first and second embodiments. An optical element having a diffuser DS can be used for devices other than the endoscope device as an optical element that diffuses only in a predetermined direction with a small amount of light distribution unevenness without reducing the amount of illumination light in the visual field. Can be done.

Also in the second and third embodiments, the convex portions P1, P2, P3, that is, the joint portion JP of the slope portions IP1 and IP2 may not be sharp, and may have a rounded shape, for example, or have multiple surfaces. It may have a chamfered shape cut by.

As described above, according to each of the above-described embodiments, the illumination optical system for an endoscope can be diffused only in a predetermined direction with a small amount of light distribution unevenness without reducing the amount of illumination light in the visual field. , Optical adapters for endoscopes and optical elements can be provided.

The present invention is not limited to the above-described embodiment, and various changes, modifications, and the like can be made without changing the gist of the present invention.

1 Endoscope device, 2 Device body, 3 Endoscope, 4 Display section, 5 Insert section, 6 Operation section, 6a curved joystick, 7 Universal cord, 10 Optical adapter, 10a ring, 10b Female screw section, 10c Inward flange Part, 10p flat part, 11, 11A tip part, 11Aa tip surface, 11a tip rigid member, 11b male screw part, 11x image pickup element, 11y, 11y1 light guide, 12 curved part, 13 flexible part, 22 observation window, 22x Observation window, 22a straight part, 23x illumination window, 23A, 23B optical member, 23a illumination window, 23a1, 23a2 optical member, 23b illumination window, 23b1 optical member, 31 adapter body, 31a, 31b hole, 32 cover member, 32a opening Part, 33 Cylindrical member, 41 Plano-concave lens, 42 Positioning part, 43 Prism part, 43a, 43b Prism, 44 Lens part, 44a lens, 45 Cover glass, 46, 46A, 46B Rod lens, 46a, 46b surface, 51 Optical transmission Optical member, 51A, 51B extension part, 51B extension part, 51U concave part, 51X partial cylindrical part, 51a exit surface, 51a1 flat part, 51b exit surface, 51b1, 51c flat part, 52 optical element, 52a incident surface.

Claims (14)

An illumination optical system for an endoscope having an insertion portion to be inserted into a subject.
It has an optical element provided at the tip end portion of the insertion portion and having an incident surface on which light is incident as incident light from the base end side of the insertion portion and an exit surface on which the light is emitted as illumination light.
The emitting surface has a diffusing portion that diffuses the emitted light.
The diffusion portion has a plurality of convex portions extending along a predetermined direction on the exit surface.
Each convex portion has a total reflection surface having a first angle with respect to the emission surface and totally reflecting the incident light, and a second angle smaller than the first angle with respect to the emission surface. It has a reflected light that is totally reflected by the total reflecting surface and a transmitting surface that transmits and emits the incident light.
Illumination optical system for endoscopes. Each of the convex portions is formed by the total reflection surface and the transmission surface so as to be plane symmetric with respect to a surface orthogonal to the emission surface and parallel to the predetermined direction. The illumination optical system for an endoscope according to claim 1, which has a convex portion. When viewed from the predetermined direction, the first angle is an angle in the range of 60 ° or more and 85 ° or less with respect to the emission surface, and the second angle is 0 with respect to the emission surface. The illumination optical system for an endoscope according to claim 1, wherein the angle is in the range of more than ° and 30 ° or less. The endoscope according to claim 2, wherein the depth of the first groove formed by the two adjacent total reflection surfaces is deeper than the depth of the second groove formed by the two adjacent transmission surfaces. Illumination optical system. A part of the plurality of convex portions is arranged on the exit surface so as to be plane-symmetric with respect to a plane parallel to the predetermined direction with respect to the other part of the plurality of convex portions. The illumination optical system for an endoscope according to claim 1. A region in which a part of the plurality of convex portions and another part of the plurality of convex portions are arranged on the emission surface in a plane symmetric manner with respect to a plane parallel to the predetermined direction is formed. The illumination optical system for an endoscope according to claim 1, which is provided in plurality. The illumination optical system for an endoscope according to claim 1, wherein the illumination optical system for an endoscope is an illumination optical system for an endoscope for direct vision, perspective view, or side view. The illumination optical system for an endoscope according to claim 7, wherein when the illumination optical system for an endoscope is an illumination optical system for direct vision, the optical element is a rod lens. When the illumination optical system for an endoscope is an illumination optical system for side vision, the optical element is one of a substantially U-shape or a substantially U-shape having two reflecting surfaces for reflecting the incident light. The illumination optical system for an endoscope according to claim 7, which is a prism having a portion shape. A first optical member provided on the emission surface side of the optical element and having a grain surface on the side opposite to the emission surface side.
The illumination optical system for an endoscope according to claim 1, further comprising the first optical member and a second optical member bonded with an adhesive on the sand grain surface. An optical adapter that can be attached to the tip of the insertion portion of an endoscope having an insertion portion to be inserted into a subject.
An optical element provided at the tip portion and having an incident surface on which light is incident as incident light from the base end side of the insertion portion and an exit surface on which the light is emitted as illumination light.
An illumination window that emits the illumination light from the emission surface of the optical element,
Have,
The emitting surface has a diffusing portion that diffuses the emitted light.
The diffusion portion has a plurality of convex portions extending along a predetermined direction on the exit surface.
Each convex portion has a total reflection surface having a first angle with respect to the emission surface and totally reflecting the incident light, and a second angle smaller than the first angle with respect to the emission surface. It has a reflected light that is totally reflected by the total reflecting surface and a transmitting surface that transmits and emits the incident light.
Optical adapter for endoscopes. The optical adapter for an endoscope according to claim 11, wherein the illumination light is emitted from the illumination window in a direction orthogonal to the longitudinal axis direction or in an oblique direction. The optical adapter for an endoscope according to claim 11, wherein the illumination light is emitted from the illumination window in front of the tip portion along the longitudinal axis direction. An optical element having an incident surface on which light is incident as incident light from the proximal end side and an emitting surface on which the light is emitted as emitted light.
The emitting surface has a diffusing portion that diffuses the emitted light.
The diffusion portion has a plurality of convex portions extending along a predetermined direction on the exit surface.
Each convex portion has a total reflection surface having a first angle with respect to the emission surface and totally reflecting the incident light, and a second angle smaller than the first angle with respect to the emission surface. It has a reflected light that is totally reflected by the total reflecting surface and a transmitting surface that transmits and emits the incident light.
Optical element.

Images