JPH11151200A - Observation image projecting part of endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an observation image projecting part of an endoscope which can obtain stable quality with small variation of the sizes of endoscope observed images displayed on a TV monitor among products of the same kind. SOLUTION: In an observation image projecting part of an endoscope which converts endoscope observation images transmitted by an optical image transmission means 12 to electric signals, projecting them on the image pick-up plane of a solid image pick-up element by a projecting lens 13, adjusting means 30, 32 and 33 are provided for the fixing part of the member to decide the distance of larger effect on the projection magnification and no adjusting means are provided for the fixing part of the member 26 to decide the distance of smaller effect on the projection magnification out of the distance between the optical image transmitting means 12 and the projecting lens 13 and the distance between the projecting lens 13 and the solid image pick-up element 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope in which an endoscope observation image transmitted by an optical image transmission means is projected onto an imaging surface of a solid-state imaging device by a projection lens and converted into an electric signal. The present invention relates to an observation image projection unit of a mirror.

[0002]

2. Description of the Related Art For example, an ophthalmic endoscope is a graded optical fiber (trade name: Selfoc type optical fiber).
The endoscope observation image transmitted to the hand side is projected by the projection lens onto the imaging surface of the solid-state imaging device, converted into an electric signal, and displayed on a television monitor.

[0003]

However, in such an observation image projection unit, the magnification of a projection image projected on an imaging screen of a solid-state imaging device fluctuates due to variations in dimensions of lenses and mechanical parts, and the like. The size of the endoscopic observation image displayed on the monitor varies between products of the same model.

Accordingly, the present invention provides an observation image projection unit for an endoscope which has a small variation in the size of an endoscope observation image displayed on a television monitor between products of the same model and can obtain stable quality. The purpose is to provide.

[0005]

In order to achieve the above object, an observation image projection section of an endoscope according to the present invention comprises: an endoscope observation image transmitted by an optical image transmission means; In an observation image projection unit of an endoscope that is configured to project an image on an imaging surface of an imaging device and convert the electrical signal into an electric signal, a distance between the optical image transmission unit and the projection lens, the projection lens and the solid Among the distances from the imaging surface of the imaging element, an adjustment unit for performing optical adjustment is provided on a fixed portion of a member that determines a distance that has a greater effect on the projection magnification, and has a smaller effect on the projection magnification. The adjustment means is not provided on the fixed portion of the member that determines the distance between the two.

[0006] The optical adjustment may be focus adjustment of a projected image of an image exit end face of the optical image transmitting means, which is projected on an imaging surface of the solid-state imaging device by the projection lens.

[0007] The optical adjustment may be an optical axis adjustment of a projected image of an image exit end face of the optical image transmitting means, which is projected on an imaging surface of the solid-state imaging device by the projection lens.

In addition, no member for optical adjustment is provided between the projection lens and the solid-state image pickup device, and there is no optical adjustment between the optical image transmitting means and the projection lens. A member for performing adjustment may be provided, and in that case, an electrical insulating member may be fixed between the projection lens and the solid-state imaging device.

The optical image transmitting means may be a graded optical fiber or an image guide fiber bundle.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows an entire configuration of the ophthalmic endoscope, and a grip portion 2 for an operator to grip is connected to a hand side of a thin and short needle-like insertion portion 1 inserted into an eyeball portion. ing.

An image of a subject is formed by an objective optical system built in the distal end of the insertion section 1, transmitted to a gripping section 2 by a graded optical fiber inserted through the insertion section 1, and then gripped. The signal is converted into an electric signal by a solid-state imaging device built in the unit 2.

The grip 2 is connected to the connector 4 by a flexible cable 3, and an imaging signal of an endoscope observation image is transmitted to the connector 4 by a signal line inserted through the flexible cable 3. The signal is transmitted to a video processor (not shown) via the signal connector section 5 to display an observation image on a television monitor.

Reference numeral 6 denotes a light guide connector for connecting the incident end of the light guide fiber for illumination to the light source device. The light guide fiber passes through the flexible cable and the grip 2 from inside the connector. The emission end is arranged at the tip of the insertion section 1 so as to illuminate the subject.

FIG. 1 shows the gripper 2. A graded optical fiber 12 is mounted on the first frame 16 of the gripper 2 to which the base end of the sheath 15 that covers the insertion section 1 is fixed.
The fiber receiver 17 to which the base end portion is fixed is bonded and fixed.

A cylindrical second frame 18 is screwed to the first frame 16 and integrally connected. Light guide fiber bundle 20 for illumination arranged surrounding graded optical fiber 12 in insertion section 1
Is passed from the inside of the grip portion 2 to the inside of the flexible cable 3 through a cutout portion formed in the fiber receiver 17 and the second frame 18.

The solid-state imaging device 14 is fixed to a support frame 22 made of a tubular member together with electronic components 23 such as a drive circuit. A signal cable 24 passed through the flexible cable 3 is connected to the rear end of the support frame 22.

A lens frame 25 for holding the objective lens group 13
Is a cylindrically formed electrically insulating member (insulating member) 2
6 and fitted and joined. Insulation member 2
The rear end portion 6 is fitted and bonded to the support frame 22 in a state where the end surface thereof is in contact with the surface of the cover glass 14a of the solid-state imaging device 14. Therefore, the positional relationship between the imaging surface of the solid-state imaging device 14 and the objective lens group 13 (more precisely, the main surface of the objective lens group 13) is determined by the dimensions of the insulating member 26.

The insulating member 26 is fitted and adhered to a metal sleeve 27 disposed so as to extend forward.
The sleeve 27 is fitted into the optical adjustment barrel 30 from behind and is pressed and fixed from the side by a fixing screw 33 screwed into the optical adjustment barrel 30.

The optical adjustment barrel 30 has a large diameter portion and a small diameter portion, and is provided between the outside diameter of the small diameter portion loosely inserted into the second frame 18 and the inside diameter of the second frame 18. Has a gap of about 0.3 mm, for example.

The tips of the three pointed screws 32 screwed into the second frame 18 from the side at an interval of, for example, about 120 ° are formed on the outer peripheral surface of the small-diameter portion of the optical adjustment barrel 30. It is engaged with the groove 31.

As a result, by tightening the pointed screw 32, the step surface between the small diameter portion and the large diameter portion of the optical adjustment barrel 30 is pressed against the rear end surface of the second frame 18, and the three pointed screws are By adjusting the tightening degree of 32,
The axial position of the optical adjustment barrel 30 with respect to the second frame 18 moves, and the image emission end face 1 of the graded optical fiber 12 is moved.
The optical axis adjustment of the objective lens group 13 and the solid-state imaging device 14 for 2a can be performed.

Further, the fixing screw 33 is loosened and the sleeve 27
Is moved in the axial direction, the objective lens group 13 and the solid-state imaging device 14 move in the optical axis direction with respect to the image emission end face 12a of the graded optical fiber 12, so that
Focus adjustment on the imaging surface of the solid-state imaging device 14 can be performed.

The periphery of the internal mechanism of the gripping portion 2 constructed as described above is covered by a front case 34 and a rear case 35 which are screwed to each other. Are provided with O-rings 36 and 37 for sealing.

FIG. 3 schematically shows an optical system according to this embodiment. An image of a subject formed by an objective lens 11 built in the tip of the insertion section 1 is converted into a graded optical fiber 12.
And is enlarged by the objective lens group 13 and projected on the imaging surface of the solid-state imaging device 14.

At this time, the graded optical fiber 12
Is the distance between the image exit end face 12a of the objective lens group 13 and the front main surface of the objective lens group 13, the distance between the rear main surface of the objective lens group 13 and the imaging surface of the solid-state image sensor 14 is b, 13
If the focal length of f is f, (1 / a) + (1 / b) = (1 / f), and the projection magnification A is A = (b / a).

Here, since a <b, the error of a has a greater effect on the projection magnification A than the error of a and the error of b. Appears as a large shift.

Therefore, in the present invention, b, which has a small effect on the projection magnification A to the solid-state imaging device 14, is left to the component accuracy of the insulating member 26 without adjustment, and has a large effect on the projection magnification A. On the side, focus adjustment and optical axis adjustment are performed. Therefore, highly accurate optical adjustment can be performed by a simple adjustment operation.

It should be noted that the present invention is not limited to the above-described embodiment.
Instead, the present invention may be applied to an endoscope or the like using an image guide fiber bundle.

[0029]

According to the present invention, of the distance between the optical image transmitting means and the projection lens and the distance between the projection lens and the imaging surface of the solid-state imaging device, the influence on the projection magnification is large. Adjustment means for optical adjustment is provided in the fixed part of the member that determines the distance between the two, so that the size of the endoscope observation image displayed on the TV monitor between products of the same model is small and stable. The optical quality can be easily adjusted because no adjusting means is provided in the fixing portion of the member that determines the distance that has less influence on the projection magnification.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a grip portion of an endoscope according to an embodiment of the present invention.

FIG. 2 is a side view showing the entire configuration of the endoscope according to the embodiment of the present invention.

FIG. 3 is a schematic diagram of an optical system of the endoscope according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Graded optical fiber 13 Objective lens group 14 Solid-state image sensor 26 Insulating member 30 Optical adjustment cylinder 32 Pointed screw 33 Fixing screw

Claims (7)

[Claims] 1. An observation image projection section of an endoscope, wherein an observation image of an endoscope transmitted by an optical image transmission means is projected by a projection lens onto an imaging surface of a solid-state imaging device and converted into an electric signal. Wherein, of the distance between the optical image transmitting means and the projection lens and the distance between the projection lens and the imaging surface of the solid-state imaging device, the one having a greater effect on the projection magnification is determined. An endoscope provided with adjusting means for performing optical adjustment in a fixed portion of a member to be adjusted, and no adjusting means provided in a fixed portion of a member for determining a distance having a smaller effect on a projection magnification. Observation image projection unit. 2. The endoscope according to claim 1, wherein the optical adjustment is a focus adjustment of a projection image of an image exit end face of the optical image transmitting means, which is projected on an imaging surface of the solid-state imaging device by the projection lens. The observation image projection unit of the mirror. 3. An optical axis adjustment of a projection image of an image exit end face of said optical image transmitting means projected onto an imaging surface of said solid-state imaging device by said projection lens.
Or the observation image projection part of the endoscope of 2. 4. A member for performing optical adjustment is not provided between the projection lens and the solid-state imaging device.
A member for performing optical adjustment is provided between the optical image transmitting means and the projection lens.
Or the observation image projection part of the endoscope of 3. 5. An observation image projection unit according to claim 4, wherein an electric insulating member is fixed between said projection lens and said solid-state image sensor. 6. An observation image projection unit according to claim 1, wherein said optical image transmission means is a graded optical fiber. 7. An observation image projection unit for an endoscope according to claim 1, wherein said optical image transmission means is an image guide fiber bundle.