JP2003070723A - Electronic endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic endoscope which has an imaging system with the outer diameter made thinner as much as possible. SOLUTION: A fillet 31 can be fixed to a glass lid 29 without interference even when the thin part 27b of a cover glass 27 is formed in a size smaller than the outline of the glass lid 29 equipped on the imaging plane 26a of a solid state imaging element 26. At that time, a part of the fillet 31 formed on the outer circumference part of the thick part 27a of the cover glass 27 is included in a projecting range of the glass lid 29. That is, the outline of the thick part 27a is formed slightly larger than the outline of the glass lid 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscope having an image pickup unit.

[0002]

2. Description of the Related Art In recent years, along with the development of electronic technology, electronization has progressed also in the field of endoscopes, and a charge-coupled device (hereinafter referred to as CC
Various types of electronic endoscopes in which an imaging unit in which a solid-state imaging device such as (also referred to as D) is disposed at the tip of the insertion portion are used. A light guide fiber that illuminates the image pickup unit and the subject is provided at the tip of the electronic endoscope.

The image pickup unit is provided with a circuit board for amplifying an electric signal which is imaged on the image pickup surface of the CCD and photoelectrically converted, and the amplified electric signal is an external device through an electric cable. It is transmitted to the camera control unit (hereinafter referred to as CCU). The CCU generates a video signal from the electric signal and outputs it to a display device such as a monitor. As a result, the endoscopic observation image is displayed on the screen of the display device.

The endoscope is washed, disinfected, or sterilized with various chemicals before it is used. The steam generated from various chemicals used for cleaning, disinfecting and sterilizing may adversely affect an operator who performs cleaning, disinfecting and sterilizing. In addition, the waste liquid of these chemicals is under strict regulations because of concern about the effect on the environment. For this reason, autoclave sterilization using high-temperature and high-pressure steam has attracted attention for the sterilization of medical equipment.

When an endoscope is sterilized by autoclaving, the endoscope is exposed to high temperature steam, and, for example, the adhesive agent that fixes the objective optical system deteriorates due to hydrolysis,
If the airtight state cannot be ensured, water vapor may enter the objective optical system and cause a problem such as clouding of the field of view.

In order to solve this problem, for example, Japanese Patent Laid-Open No.
According to Japanese Patent Laid-Open No. 000-115594, an optical lens located closest to a subject part of an objective optical system and an optical member located closest to an image sensor are fixed to a frame by soldering, and the optical lens is exposed to high temperature high pressure steam. There is shown a solid-state imaging device unit in which the fixing means of the objective optical system is not deteriorated when the endoscope is exposed and water vapor is prevented from entering the objective optical system to cloud the visual field.

[0007]

However, in the solid-state image pickup device unit disclosed in Japanese Unexamined Patent Publication No. 2000-115594, the optical member located closest to the image pickup device is fixed to the frame body by soldering, so that the solder fillet is used. It is formed on the imaging element side of the optical member. Therefore, in order to attach the optical member having the solder fillet and the image pickup surface of the image pickup device so as to be in close contact with each other, the outer shape of the optical member is compared with the image pickup surface so that the solder fillet portion is surely located outside the image pickup surface. However, the size of the solid-state image sensor unit is prevented from being further reduced.

The present invention has been made in view of the above circumstances, and an electronic endoscope having an image pickup unit in which the outer diameter is formed as small as possible to prevent the objective optical system from being fogged during autoclave sterilization. The purpose is to provide a mirror.

[0009]

The electronic endoscope of the present invention comprises:
An objective lens unit having an objective optical system for obtaining an optical image of an object to be observed, which is formed by providing an optical member on a lens frame, and an element frame which is airtightly bonded and fixed to the base end side of the lens frame by an airtight bonding member. An electronic endoscope including an image pickup unit including an optical member to be fixed and an element unit provided with a solid-state image pickup element having an image pickup surface arranged at an image forming position of the objective lens unit, wherein the element frame A metallized surface is provided on the fitting surface of the optical member that is fitted to the front surface of the imaging surface of the solid-state imaging device, and an interference prevention optical section that prevents the imaging surface and the airtight bonding member from interfering with each other is provided. It is provided.

The interference prevention optical portion is a small diameter portion of an optical member whose cross-sectional shape in the optical axis direction is formed in a substantially convex shape, and the metallized surface is provided on the side surface of the large diameter portion of the optical member. .

In addition, the interference prevention optical section has a second diameter smaller than that of the first optical member, which is disposed on the image pickup surface of the solid-state image pickup element and has a metallized surface on a side surface fitted to the element frame. It is an optical member.

According to this structure, the optical member can be hermetically bonded to the element frame by soldering or the like, and the hermetic bonding member at the time of hermetic bonding interferes with the image pickup surface of the solid-state image pickup device by the interference prevention optical section. Is prevented.

Further, since the interference preventing optical portion arranged in front of the image pickup surface has a small diameter, it is not necessary to make the size of the optical member hermetically bonded to the element frame extremely larger than the image pickup surface of the solid-state image pickup element.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 relate to a first embodiment of the present invention, FIG. 1 is a view for explaining an electronic endoscope, and FIG. 2 is a longitudinal axis direction cross-sectional view for explaining a distal end side of an insertion portion of the electronic endoscope. 3, FIG. 3 is a partial cross-sectional view showing a light guide fiber arranged on the distal end side of the insertion portion, FIG. 4 is a view for explaining the image pickup unit, FIG. 5 is an enlarged view of a main part of the image pickup unit, and FIG. 6 is a cover. It is sectional drawing which compares and demonstrates the magnitude | size of glass and a glass lid.

As shown in FIG. 1, an electronic endoscope (hereinafter, referred to as an endoscope) 1 of the present invention has a charge-coupled device (for example, a photoelectric conversion device which changes an optical image of a portion to be examined into an electric signal on the tip side). Less than,
A slender insertion section 2 having a built-in image pickup unit, which will be described later, including a solid-state image pickup device such as a CCD).
And an operating section 3 which also serves as a grip section and which is continuously provided on the proximal end side of the insertion section 2, and a universal cord 4 extending from the side section of the operating section 3. A connector portion 5 connected to a light source device (not shown) is provided at an end of the universal cord 4.

The connector section 5 has a camera control unit (not shown) for generating a video signal from an electric signal transmitted from the image pickup unit (hereinafter referred to as CCU).
(Hereinafter abbreviated)) is provided with an electric connector portion 5a to which an electric cable is connected. Also, the CCU
A display device (not shown) for displaying a video signal generated by the CCU is connected to the.

The insertion portion 2 includes a hard tip portion 6 and a bendable bending portion 7 which is continuously provided on the proximal end side of the hard tip portion 6.
It is composed of a long flexible tube portion 8 which is continuously provided on the base end side of the curved portion 7.

The operation portion 3 is provided with a bending operation lever 9. The bending portion 7 can be bent by rotating the bending operation lever 9. Further, a treatment instrument insertion port 10 for inserting a treatment instrument such as biopsy forceps (not shown) for collecting body tissue of a patient is provided on the distal end side of the operation section 3. Further, various switches 11 such as a suction button for operating a suction device (not shown) and a release switch for controlling an endoscopic image displayed on the display device are arranged at the proximal end of the operation unit 3. There is.

The tip surface 6a of the hard tip 6 of the insertion portion 2
In addition, as an illuminating means, an illumination window 12 that constitutes an illumination optical system that illuminates illumination light from a light guide fiber described later by diverging it to a required angle and irradiating with the illumination light emitted from the illumination window 12 is provided. An observation window 13 that constitutes an imaging unit that is an observation optical system that takes in an optical image of the inspection part and an opening 14a that serves as a lead-out port for a treatment instrument conduit 14 that communicates with the treatment instrument insertion port 10 are provided.

The structure of the image pickup unit will be described with reference to FIGS. As shown in FIG. 2, the distal end hard portion 6 of the insertion portion 2 is formed of a substantially cylindrical metal frame 15. The through hole provided in the metal frame 15 includes an objective lens unit 24 that constitutes the image pickup unit 20 as a built-in object,
A metal base 16 that constitutes the treatment instrument conduit 14 and a light guide fiber 17 that guides illumination light from a light source device (not shown) that constitutes the illumination optical system shown in FIG. 3 are arranged. A channel tube 18 that communicates with the treatment instrument insertion port 10 that constitutes the treatment instrument conduit 14 is connected to the proximal end portion of the metal base 16. Further, a distal end joint piece 7a that constitutes the most distal end of the bending portion 7 is fixed to the base end portion of the metal frame 15, and is formed of a stretchable resin member that forms the exterior of the bending portion 7. One end of the curved cover 19 is fixed.

As shown in FIGS. 2 and 4, the objective lens unit 24 includes a plurality of optical lenses 2 which are objective optical systems.
1, a spacing ring 21a, a diaphragm 21b, and a lens frame 22 which is a frame body in which these optical members are arranged, for example, made of stainless steel or the like. An element frame 23 made of, for example, stainless steel or the like, which constitutes the element unit 25 of the image pickup unit 20, is arranged in the lens frame 22. That is, the image pickup unit 20 includes the objective lens unit 24 and the element unit 25.

The element unit 25 has a CCD 26 for picking up an optical image of an object to be inspected having an image pickup surface 26a at the image forming position of the objective lens unit 24, and the element frame 23.
A cover glass 27 fixed to the front side of the solid-state image sensor 26 and having a large diameter portion 27a and a small diameter portion 27b, which is a light-transmissive optical member having a substantially convex cross section. A circuit board 28 provided with a drive signal for driving the solid-state image pickup device 26 and an integrated circuit for performing signal processing of electric signals photoelectrically converted by the solid-state image pickup device 26, and an image pickup surface 26a of the solid-state image pickup device 26 are optically transparent. And a glass lid 29 which is a light-transmissive optical member adhered and fixed by an ultraviolet-curable optical adhesive.

The small-diameter portion 27 of the cover glass 27
The end surface 27c of b and the glass lid 29 are adhered and fixed by a light-transmissive UV-curable optical adhesive. That is, the solid-state imaging device 26 is the glass lid 2
It is adhesively fixed to the cover glass 27 via 9.

A cable 30 having a plurality of signal lines 30a connected to the connector 5 is inserted at the base end of the image pickup unit 20. This cable 30
Each of the signal lines 30a therein is electrically connected to a predetermined position of the circuit board 28 and the lead 26b extending from the side portion of the solid-state image pickup device 26 to the side opposite to the image pickup surface side.

As a result, an image is formed on the image pickup surface 26a of the solid-state image pickup device 26 after passing through the plurality of optical lenses 21 constituting the objective lens unit 24, the cover glass 27 of the element unit 25, and the glass lid 29. The optical image of the tested portion is converted into an electric signal by the solid-state imaging device 26, subjected to signal processing such as amplification by the circuit board 28, and transmitted to the CCU via the signal line 30a and the connector portion 5. To be done.

A metallized surface is provided on the side peripheral surface of the observation window 13 constituting the objective lens unit 24 shown in FIG. Observation window 1 provided with this metallized surface
3 is airtightly integrally fixed to the lens frame 22 by soldering or brazing using an airtight joining member such as solder or brazing.

On the other hand, as shown in FIG. 5, a metallized surface is also provided on the side peripheral surface of the large diameter portion 27a of the cover glass 27 constituting the element unit 25. The large diameter portion 27a of the cover glass 27 provided with this metallized surface
Are integrally fixed to the element frame 23 by airtight bonding such as soldering or brazing. By performing this airtight joining, a fillet 31 made of solder or solder is formed around the base end of the element frame 23 and the large diameter portion 27a of the cover glass 27.

At the time of the airtight joining with the solder or the solder, in the present embodiment, the solder or the solder cover glass 27 is used.
The fillet 31 is formed only on the base end face side of the element frame 23 because it flows into the gap formed between the large diameter portion 27 a of the element frame 23 and the inner peripheral surface of the element frame 23 by the capillary phenomenon. That is, the end surface 2 on the imaging surface side of the small diameter portion 27b of the cover glass 27.
Solder or brazing material does not flow into the edge of 7c to form a fillet.

Therefore, as shown in FIG. 6, even if the small diameter portion 27b of the cover glass 27 is formed smaller than the outer shape of the glass lid 29 provided on the image pickup surface 26a of the solid-state image pickup device 26, the fillet 31 is formed. Can be fixed to the glass lid 29 without interference.

At this time, part of the fillet 31 formed on the outer peripheral portion of the large diameter portion 27a of the cover glass 27 is
It is included in the projection range of the glass lid 29. That is, the outer diameter of the large diameter portion 27a is formed to be slightly larger than the outer diameter of the glass lid 29.

The lens frame 22 and the element frame 23 are hermetically fixed integrally by soldering, laser welding or the like. As a result, the observation window 13 of the lens frame 22 and the cover glass 2 of the element frame 23
The space between 7 and 7 becomes an airtight space.

Further, the cover glass 2 in the present embodiment.
The material of 7 is preferably sapphire that does not deteriorate even when exposed to autoclave sterilization, or multi-component glass that does not easily change, and the surface 27d of the large diameter portion 27a of the cover glass 27 is not limited to a flat surface but is a convex surface. May be.

Further, in this embodiment, the element frame 23
An ultraviolet curing type optical adhesive is used to bond and fix the solid-state imaging device 26 to the cover glass 27 integrated with the glass lid 29 via the glass lid 29.
In the case where it is blocked by 3, an atmosphere curing type optical adhesive such as a thermosetting type or a moisture curing type is used instead of this adhesive.

Further, the metallized surface is made of Cr or C.
A metal such as u, Ni or Au is provided on the metal surface by vapor deposition or plating.

Thus, the observation window is airtightly joined to the lens frame, the large diameter portion of the cover glass is airtightly joined to the element frame, and the lens frame and the element frame are airtightly joined.
Make the space between the observation window and the cover glass an airtight space,
When the electronic endoscope is autoclaved, it is possible to reliably prevent the objective optical system from being exposed to water vapor.
As a result, it is possible to prevent image abnormalities such as clouding of the visual field from occurring in the electronic endoscope.

The cover glass, which is airtightly joined to the element frame, is formed in a convex shape having a large diameter portion and a small diameter portion, and the large diameter portion is airtightly joined to the element frame, so that the cover glass is formed by soldering or brazing. It is possible to reliably prevent the fillet from hitting the edge of the small diameter portion located on the image pickup surface side of the solid-state image pickup element. With this, the fillet formed on the outer peripheral side of the large-diameter portion has a size that covers the imaging surface, that is, without forming the large-diameter portion extremely large with respect to the imaging surface, the element unit is configured, It is possible to reduce the diameters of the imaging unit and the electronic endoscope.

In the present embodiment, the cover glass 27 is formed in a convex shape having the large diameter portion 27a and the small diameter portion 27b, but a diagram for explaining another configuration of the cover glass shown in FIG. The cover glass 40 and the element frame 2
A first cover glass 41, which is a first optical member to be joined to 3 by soldering or brazing, and the first cover glass 41.
The second cover glass 42 is a second optical member having a smaller outer shape, and the cover glass 40 is formed by bonding and fixing with an atmosphere curing type optical adhesive such as an ultraviolet curing type or a thermosetting type. The solid-state image sensor 26 may be bonded and fixed to the second cover glass 42 of 40 with an atmosphere curing type optical adhesive such as an ultraviolet curing type or a thermosetting type.

Further, in this embodiment, the element frame 23
Although the end face of the base end portion is formed only up to the edge of the large diameter portion 27a of the cover glass 27, as in the element frame of the figure for explaining the other configuration of the element frame shown in FIG. Jaw 43a protruding from the edge of 27a and overlapping the glass lid 29
Alternatively, the element frame 43 may be formed. Then, an adhesive is filled between the jaw portion 43a and the solid-state imaging device 26.

As a result, the cover glass 27 and the solid-state image pickup device 26 are bonded and fixed by the optical adhesive or the like, and the solid-state image pickup is performed by the adhesive filled between the solid-state image pickup device 26 and the jaw 43a. Since the element 26 is held with respect to the element frame 43, peeling of the optical adhesive that fixes the cover glass 27 and the solid-state imaging element 26 is prevented. It should be noted that, as shown in the diagram for explaining another configuration of the element frame in FIG. 9, the same action and effect can be obtained even if the element frame 45 is configured separately from the frame portion 45a and the jaw portion 45b. .

FIG. 10 is a view for explaining another structure of the image pickup unit according to the second embodiment of the present invention. As shown in the figure, the image pickup unit 50 of the present embodiment includes an objective lens unit 24 configured by disposing a plurality of optical lenses 51a, a spacing ring 51b, a diaphragm 51c, and the like in a lens frame 51, and a solid-state image pickup element in an element frame 52. 26, and the element unit 25 in which the glass lid 53 provided on the image pickup surface side of 26 is arranged.

Then, as in the first embodiment, the observation window 13 arranged at the most distal end side of the lens frame 51 is airtightly joined to the lens frame 51. The lens frame 51 and the element frame 52 are airtightly joined by soldering or laser welding.

In the present embodiment, the glass lid 53 and the element frame 52 are fixed by an adhesive 54 such as an epoxy adhesive having a low vapor permeability or a ceramic adhesive containing alumina or zirconia as a main component. Is going. At this time, at least a part of the glass lid 53 is fitted and arranged in the element frame 52 to be adhesively fixed.

That is, in this embodiment, the element frame 5
The glass lid 53 provided on the image pickup surface side of the solid-state image pickup device 26 is directly fitted to the solid state image pickup device 2 in FIG. Therefore, in the image pickup unit 50, the cover glass is omitted.
That is, the structure does not have a bonding surface between optical members made of an adhesive such as an optical adhesive.

In the present embodiment, the material of the glass lid 53 is sapphire that does not deteriorate even when exposed to autoclave sterilization, or multi-component glass that does not easily change.

Further, in the image pickup unit 50 of the present embodiment, the element frame 52 and the glass lid 53 are adhered and fixed by the adhesive 54 having a low vapor permeability, so that the element frame 52 and the glass lid 53 are completely bonded to each other. Although it is not possible to make it air-tight, since the element frame 52 and the glass lid 53 are fitted to each other and the adhesive 54 is applied and fixed by adhesion, compared with the image pickup unit configured using the conventional adhesive. Thus, during autoclave sterilization, it is difficult for water vapor to enter the objective optical system.

Further, the glass lid 53 is attached to the element frame 5
2 may be joined airtightly as in the first embodiment.

As described above, the glass lid is provided on the image pickup surface side of the solid-state image pickup element, and at least a part of the glass lid is directly fitted into the element frame and integrally fixed, whereby the hardness of the image pickup unit is improved. The length can be shortened.

Further, it is possible to eliminate the trouble caused by the peeling of the adhesive by eliminating the bonding surface between the optical members with the adhesive.

Here, the procedure for assembling the image pickup unit 20 will be described with reference to FIGS. 11 is a diagram showing a lens frame in which an observation window is airtightly joined, FIG. 12 is a diagram showing an element frame in which a cover glass is airtightly joined, FIG. 13 is a diagram illustrating an objective lens unit, and FIG. 14 is a coverglass is airtight. FIG. 15 is a diagram for explaining the relationship between the joined element frame and the adjustment imaging unit, FIG. 15 is a diagram for explaining the position adjustment of the objective lens unit with respect to the element frame, and FIG. 16 is an objective lens unit whose position is adjusted with respect to the element frame. FIG. 17 is a diagram showing a provisional image pickup unit in which is arranged, and FIG. 17 is a diagram explaining the assembled image pickup unit.

In FIG. 11, the inner peripheral surface of the lens frame is shown in a straight shape to simplify the drawing.

First, as shown in FIGS. 11 and 12, the observation window 13 and the cover glass 27 having a metallized surface provided with a metal such as Cr, Cu, Ni or Au on the side peripheral surface by vapor deposition or plating. The large diameter portion 27a is airtightly joined to the lens frame 22 and the element frame 23 by soldering or brazing.

Next, as shown in FIG. 13, a plurality of optical lenses 21 are attached to the lens frame 22 to which the observation window 13 is airtightly joined.
The objective lens unit 24 is constructed by assembling the space ring 21a and the diaphragm 21b.

On the other hand, as shown in FIG. 14, on the end face of the small diameter portion 27b of the cover glass 27 airtightly joined to the element frame 23,
The tip surface of the glass lid 62 of the image pickup unit 60 for adjustment in which the solid-state image pickup element 61, the glass lid 62, the signal line 63a of the cable 63, the lead 61b, and the circuit board 64 are provided at predetermined positions using an assembly jig (not shown). To place.

Then, as shown in FIG. 15, the objective lens unit 24 is assembled to the element frame 23 arranged in the adjustment image pickup unit 60, and the focus is adjusted so that a predetermined resolving power can be obtained. Element frame 2
It is temporarily fixed to 3 by spot welding such as laser.

Next, while holding this temporarily fixed state, the adjusting image pickup unit 60 is removed from the element frame 23 to which the objective lens unit 24 is temporarily fixed, and again using seam welding such as laser, as shown in FIG. In this way, the objective lens unit 24 in which the observation window 13 is airtightly joined and the element frame 23 in which the cover glass 27 is airtightly joined are airtightly joined to form the provisional imaging unit 20A.

After that, the airtight state of the temporary image pickup unit 20A is inspected. Here, it is confirmed whether or not the airtight state of the provisional imaging unit 20A has reached a predetermined value, and if it has reached the predetermined value, the small diameter portion 27b of the cover glass 27.
The solid-state imaging device 26 is adhered and fixed to the end face on the side with an atmosphere curing type optical adhesive such as a thermosetting type or a moisture curing type, and then,
The circuit board 28 and the cable 30 are assembled. As a result, the image pickup unit 20 shown in FIG. 17 is completed. On the other hand, when the airtight state of the temporary image pickup unit 20A has not reached the predetermined value, the provision of the image pickup unit using the temporary image pickup unit 20A is abandoned.

In this way, the temporary image pickup unit is assembled,
After obtaining the result of checking the airtight state of this temporary image pickup unit, by mounting the solid-state image pickup element, the circuit board, the cable, etc., the expensive solid-state image pickup element is not wasted, and the autoclave sterilization resistance is improved. It is possible to provide the image pickup unit having the device at a relatively low cost.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[Additional Notes] According to the above-described embodiment of the present invention described in detail above, the following configuration can be obtained.

(1) An objective lens unit having an objective optical system for obtaining an optical image of an observation object, which is constructed by providing an optical member on a lens frame, and an element frame which is hermetically bonded and fixed to the base end side of the lens frame. In an electronic endoscope including an image pickup unit including an optical member integrally fixed to the above with an airtight joining member, and an element unit provided with a solid-state image pickup element having an image pickup surface arranged at an image forming position of the objective lens unit. An interference that prevents the image pickup surface and the airtight joining member from interfering with the front surface of the image pickup surface of the solid-state image pickup element by providing a metallized surface on the fitting surface of the optical member that fits in the element frame. An electronic endoscope provided with a prevention optical unit.

(2) The interference prevention optical portion is a small diameter portion of an optical member whose cross-sectional shape in the optical axis direction is formed in a substantially convex shape, and the metallized surface is provided on the side surface of the large diameter portion of the optical member. The endoscope according to attachment 1.

(3) The interference prevention optical section has a diameter smaller than that of the first optical member, which is disposed on the image pickup surface of the solid-state image pickup element and has a metallized surface on a side surface fitted to the element frame. 2. The electronic endoscope according to appendix 1, which is an optical member.

(4) An objective lens unit having an objective optical system for obtaining an optical image of an object to be observed, which is constructed by providing an optical member on the lens frame, and an element frame which is hermetically bonded and fixed to the base end side of the lens frame. And an electronic endoscope having a solid-state imaging device having an imaging surface arranged at the imaging position of the objective lens unit, an optical member provided on the imaging surface of the solid-state imaging device, directly on the element frame, Electronic endoscope that is fitted and arranged.

As a result, the solid-state image pickup element is attached to the element frame by the optical member provided on the image pickup surface without interposing other optical members, so that the rigid length of the image pickup unit can be shortened.

[0065]

As described above, according to the present invention, an electronic endoscope having an image pickup unit in which the outer diameter is formed as small as possible to prevent the objective optical system from being fogged during autoclave sterilization. Can be provided.

[Brief description of drawings]

1 to 6 relate to a first embodiment of the present invention, and FIG. 1 is a diagram for explaining an electronic endoscope.

FIG. 2 is a cross-sectional view in the longitudinal axis direction for explaining the distal end side of the insertion portion of the electronic endoscope.

FIG. 3 is a partial cross-sectional view showing a light guide fiber arranged on the distal end side of an insertion portion.

FIG. 4 is a diagram illustrating an imaging unit.

FIG. 5 is an enlarged view of a main part of an imaging unit.

FIG. 6 is a cross-sectional view for comparing and explaining the sizes of a cover glass and a glass lid.

FIG. 7 is a diagram illustrating another configuration of the cover glass.

FIG. 8 is a diagram illustrating another configuration of the element frame.

FIG. 9 is a diagram illustrating another configuration of the element frame.

FIG. 10 is a diagram illustrating another configuration of the image pickup unit according to the second embodiment of the present invention.

11 to 17 are views for explaining an assembling procedure of the image pickup unit 20, and FIG. 11 is a view showing a lens frame in which an observation window is airtightly joined.

FIG. 12 is a view showing an element frame in which a cover glass is airtightly joined.

FIG. 13 is a diagram illustrating an objective lens unit.

FIG. 14 is a diagram illustrating a relationship between an element frame in which a cover glass is airtightly joined and an adjustment imaging unit.

FIG. 15 is a diagram for explaining position adjustment with respect to the element frame of the objective lens unit.

FIG. 16 is a diagram showing a provisional imaging unit in which an objective lens unit whose position is adjusted with respect to an element frame is arranged.

FIG. 17 is a diagram illustrating an assembled imaging unit.

[Explanation of symbols]

20 ... Imaging unit 22 ... Lens frame 23 ... Element frame 24 ... Objective lens unit 25 ... Element unit 27 ... Cover glass 27a ... Large diameter part 27b ... small diameter part 29 ... Glass lid 31 ... fillet

Claims (3)

[Claims] 1. An objective lens unit having an objective optical system for obtaining an optical image of an observation object, which comprises an optical member provided in a lens frame, and an element frame which is hermetically bonded and fixed to a base end side of the lens frame. An electronic endoscope including an image pickup unit including an optical member integrally fixed by an airtight joining member and an element unit provided with a solid-state image pickup element having an image pickup surface arranged at an image forming position of the objective lens unit, A metallized surface is provided on the fitting surface of the optical member that fits into the element frame, and the front surface of the image pickup surface of the solid-state image pickup element,
An electronic endoscope comprising an interference prevention optical section for preventing the image pickup surface and the airtight joining member from interfering with each other. 2. The interference prevention optical part is a small diameter part of an optical member in which a cross-sectional shape in the optical axis direction is formed into a substantially convex shape.
The endoscope according to claim 1, wherein the metallized surface is provided on a side surface of a large diameter portion of the optical member. 3. The second optical member, which has a diameter smaller than that of the first optical member, which is disposed on the image pickup surface of the solid-state image pickup element and has a metallized surface on a side surface fitted to the element frame. The electronic endoscope according to claim 1, wherein the electronic endoscope is an optical member.