JP2000271066A - Image pickup device for endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote the reduction of endoscope diameter by lowering the height of an image pickup device. SOLUTION: In the image pickup device holding a camera cone 12 including an objective optical system 10 by a camera cone holding member 13 and photodetecting image light passing through these members by a CCD 16, an optical path length BF between the rear end position of the cone 12 and the photodetecting position of the CCD 16 is adjusted to allow the member 13 to have an interval L1. Then, the upper surface of the cover glass 15 of the CCD 16 is approached adjacently to a cut part 21 obtained by plane-cutting the outer peripheral surface of the member 13 having this interval L1 to arranged the assembling body of the CCD 16. Thus, the height of the image pickup device can be lowered by the portion of the thickness of the part 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device for an endoscope,
In particular, the present invention relates to an imaging device having a configuration in which image light passing through a lens barrel is guided to a solid-state imaging device via a prism or the like, and relates to a structure that promotes a reduction in the diameter of an endoscope.

[0002]

2. Description of the Related Art FIG. 2 shows a configuration of an image pickup device recently used in a conventional electronic endoscope or the like. The apparatus shown in FIG. 2 is housed in a distal end portion of an endoscope, and includes, for example, an objective optical system 1 including a first lens 1A disposed on the distal end surface as a lens barrel 2. The lens barrel 2 is a cylindrical lens barrel. It is held by the holding member 3. A prism 4 is attached to the rear of the lens barrel holding member 3, and a CCD (Charge Coupled Device) as a solid-state imaging device is attached to the prism 4 via a cover glass 5.
e) 6 is optically connected. The CCD 6 is electrically connected to a circuit board 7, and a signal line (not shown) for transmitting a video signal is attached to the circuit board 7.

According to such an imaging apparatus, the image light captured by the objective optical system 1 is reflected by the prism 4 and reaches the imaging surface (upper surface) of the CCD 6,
The CCD 6 outputs a charge amount corresponding to the incident light as a video signal, and processes the video signal to form an image of the inside of the body to be observed.

[0004]

In this type of endoscope, the diameter of the end of the endoscope has been reduced, and the mounting structure of the CCD 6 has been improved. For example, as shown in Japanese Patent Application Laid-Open No. 4-314015, the CCD 6 is housed in a package that functions as a circuit board.
The cover glass 5 is adhered to the upper surface of the CCD 6 as shown in FIG. 1, and the outer periphery of the CCD 6 and the cover glass 5 including the overlapping portion of both are filled with an adhesive 8 or the like, so that the height of the imaging device is increased. h1 is set to be slightly lower. Here, the optical axis 100 of the lens barrel 2 in FIG. 2 is parallel to the endoscope axis (length axis), and the height h
Reducing the value of 1 promotes diameter reduction.

However, various mechanisms relating to imaging and treatment,
Because of the necessity of adding a structure, further reduction in the diameter of the endoscope tip is demanded, and if further improvement can be achieved with respect to the mounting portion of the lens barrel 2 having the objective optical system 1 and the CCD 6 described above. , Can contribute to the promotion of thinning.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an endoscope imaging apparatus capable of promoting the reduction in the diameter of an endoscope.

[0007]

To achieve the above object, the present invention provides a lens barrel including an objective optical system, a lens barrel holding member for holding the lens barrel, the lens barrel and the lens barrel holding member. An imaging device for an endoscope, comprising: a solid-state imaging device for receiving light passing through the member; and a solid-state imaging device assembly disposed at a position parallel to the optical axis of the lens barrel. By adjusting the optical path length between the rear end position of the barrel and the light receiving position of the solid-state imaging device, an interval in the optical path direction is provided in the lens barrel holding member, and the outer peripheral surface of the lens barrel holding member having this interval And the upper surface side of the image pickup element assembly is disposed close to the cut portion.

According to the above arrangement, a predetermined space is formed in the holding portion by moving the lens barrel to the front side, and a cut portion can be provided at the lower end of the outer periphery of the space portion. For example, the upper surface of the cover glass of the element assembly is disposed so as to bite. Therefore, as compared with the related art, the overall height of the imaging apparatus can be reduced by the thickness of the cut portion. The lens barrel holding member serves to adjust the front and rear positions of the lens barrel, and is an essential member.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of an endoscope image pickup apparatus according to an embodiment, and this image pickup apparatus is disposed in the distal end of an electronic scope. In FIG. 1, the objective optical system 10 includes a first lens 10A (observation window) exposed on the distal end surface, and the objective optical system 10 is built in a lens barrel 12. The lens barrel 12 is held by a cylindrical lens barrel holding member 13 arranged on the outer peripheral portion, and by moving the lens barrel 12 back and forth within the lens barrel holding member 13, optical adjustment such as focusing can be performed. It has become.

A CCD (Charge Coupler) is provided behind the lens barrel holding member 13 via a prism 14 and a cover glass 15.
ed Device) 16 is arranged, and the imaging surface S 1 of the CCD 16 is parallel to the optical axis 101 of the lens barrel 12.
Although details of the CCD 16 are not drawn, a lead wire protruding from the imaging surface side is connected to the circuit board 17 and the periphery of the cover glass 15 placed on the imaging surface S1 so as to sandwich the lead wire. The parts are adhered with an adhesive or the like. Further, as shown in FIG.
The space between the CCD 16 and the cover glass 15 (small space) is made airtight by filling the space between the periphery of the D16 and the circuit board 17. A transmission signal line for a video signal or the like is connected to the circuit board 17.

The holding member 13 having such a structure is provided with an interval of the optical path length L1 as shown in FIG. That is,
In this example, the distance between the rear end surface (rear end position) S2 of the objective optical system 10 of the lens barrel 12 and the imaging surface (light receiving position) S1 of the CCD 16 is the optical path length BF.
The above-mentioned interval L1 is formed without changing the image formation size or the like.

The extension of the optical path length BF is achieved, for example, by changing the radius of curvature Ra of the rear end surface S2 of the objective optical system 10 (rear lens) to the rear end surface radius of curvature R of the conventional objective optical system 1 (FIG. 2).
changing the radius of curvature of the lens, such as making it smaller than a 'or making the radius of curvature Rb of the rear end surface S3 of the first lens 10A smaller than the radius of curvature Rb' of the rear end surface of the conventional first lens 1A; Further, it can be performed by, for example, inserting a parallel plane plate 20 into the space formed by the above-mentioned interval L1.

The lower surface of the outer periphery of the portion where the distance L1 of the holding member 13 is set is cut horizontally and flatly to form a cut portion 21, and the upper surface of the cover glass 15 is brought close to the flat surface of the cut portion 21. The assembled body of the CCD 16 is disposed, and the cover glass 15 and the prism 14 are bonded. Note that the lower side of the prism 14 is also the cut portion 2.
It will be cut by one thickness or shifted upward.

As described above, in this example, the entire length L2 of the lens barrel 12 and the lens barrel holding member 13 is changed to the conventional length L3.
Although the distance L1 is longer than that of FIG. 2 by the distance L1, the length L2 can be reduced by reducing the overall thickness of the objective optical system 10. Recently, CCD16
The size of the objective optical system 10 also tends to be reduced as a result of the miniaturization of the optical system, which also shortens the length L2.

In the embodiment, the image light captured by the objective optical system 10 reaches the image pickup surface of the CCD 16 with the same image size as that of the prior art.
An image of the inside of the object to be observed is captured by the CD 6. Then, the height h2 of the image pickup device of this example is, for example, about 0.21 mm lower than the conventional height h1. That is, conventionally, as shown in FIG. 2, the distance d between the outer peripheral position of the lens barrel 2 and the upper surface of the cover glass 5 is 0.25,
In this example, as shown in FIG. 1, the distance d between the outer peripheral position of the lens barrel 12 and the upper surface of the cover glass 15 is 0.04, and the difference is 0.25 mm by 0.25-0.04 = 0.21.
Becomes As a result, the diameter of the distal end portion of the endoscope is further reduced.

[0016]

As described above, according to the present invention,
Adjusting the optical path length between the rear end position of the lens barrel and the light receiving position of the solid-state imaging device to provide a predetermined interval in the lens barrel holding member, and cutting the outer peripheral surface of the lens barrel holding member having this interval, Since the imaging element member is arranged close to the cut portion, the height of the imaging device can be reduced, and as a result, there is an advantage that the diameter of the endoscope can be reduced.

[Brief description of the drawings]

FIG. 1 shows a configuration of an imaging device for an endoscope according to an embodiment of the present invention, wherein FIG. 1 (A) is a front view and FIG. 1 (B) is a side sectional view.

FIG. 2 shows a configuration of a conventional endoscope imaging apparatus, wherein FIG. 2A is a front view, and FIG.

[Explanation of symbols]

 1,10 ... objective optical system, 2,12 ... lens barrel, 3,13 ... lens barrel holding member, 4,14 ... prism, 5,15 ... cover glass, 6,16 ... CCD, 21 ... cutting part.

Claims (1)

[Claims] 1. A lens barrel that includes an objective optical system, a lens barrel holding member that holds the lens barrel, and a solid-state imaging device that receives light that has passed through the lens barrel and the lens barrel holding member. An imaging device for an endoscope, comprising a solid-state imaging device assembly disposed at a position parallel to an optical axis of the lens barrel, wherein a position between a rear end position of the lens barrel and a light receiving position of the solid-state imaging device By adjusting the optical path length of the lens barrel holding member, an interval in the optical path direction is provided in the lens barrel holding member, and the outer peripheral surface of the lens barrel holding member having this interval is cut. An imaging device for an endoscope, characterized in that the sides are arranged close to each other.