JPH114802A - Focus adjusting device of endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focus adjusting mechanism of an endoscope which is simple in constitution and capable of miniaturization. SOLUTION: An objective-lens group L1 is guided to a fixed lens-barrel 17 along an optical axis via a lens holding frame 15 in such a way as to freely make parallel movement, and an electromagnetic actuator stator 21 having coils arranged at first intervals along the optical axis O of the objective lens group L1 is fixed to the fixed lens-barrel 17. An electromagnetic actuator moving element 31 fixed in a proximate, opposite position to the electromagnetic actuator stator 21 and having magnetic bodies arranged along the optical axis O at second intervals greater than the first intervals of the coils is fixed to the lens holding frame 15, and the objective lens group L1 is moved in steps along the optical axis O by the electromagnetic actuator stator and moving element 21, 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a focusing device for an endoscope.

[0002]

2. Description of the Related Art Observation distances for endoscopes, rigid endoscopes and the like (hereinafter referred to as "endoscopes") are, for example, one to two centimeters to ten and several centimeters used for the stomach and used for the large intestine Things can be up to a few centimeters. Therefore, conventionally, a pan focus lens that is focused within these observation distances has been used. In this case, relatively good focus can be obtained over a wide range, but in order to perform more precise observation, it is desired that the focus be accurately adjusted at any distance and at a shorter distance. Therefore, in an endoscope capable of adjusting the focus, a wire or a motor is used as a mechanism for moving the objective lens group toward and away from the incident end face of the image fiber. However, there has been a problem that these conventional lens driving mechanisms become large and the mechanisms become complicated. for that reason,
It was difficult to mount a device requiring a small size and a small diameter.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an endoscope focusing apparatus which has a simple structure and can be reduced in size.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is a focus adjusting device for moving an objective lens group of an endoscope along an optical axis, wherein the objective lens group is movable parallel to the optical axis. A guide member, and an electromagnetic actuator for moving the objective lens group along the optical axis, the electromagnetic actuator is fixed to a fixed portion of the endoscope,
An electromagnetic actuator stator including a coil disposed at a first pitch along the optical axis, and fixed to the lens frame so as to be close to and facing the electromagnetic actuator stator;
And a magnetic body disposed along the optical axis at a second pitch different from the coil. The objective lens group is movably guided in parallel with the optical axis via a lens holding frame, and is moved along the optical axis via the lens holding frame by an electromagnetic actuator.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an outline of a distal end portion of a body insertion portion of an endoscope according to one embodiment of the present invention. An image fiber 13 is guided into the distal end portion 11 of the insertion portion inside the endoscope, and an observation image is formed on the incident end face 13i by the objective lens group L1. The objective lens group L1 is fixed to a cylindrical lens holding frame 15, and the lens holding frame 15 is guided by a fixed lens barrel 17 so as to be movable in parallel with the optical axis O of the objective lens group L1. For example, one or two or more guide grooves are formed on the inner peripheral surface of the fixed lens barrel 17 in parallel with the optical axis O, and the lens holding frame 15 is provided with guide protrusions which are slidably fitted in the guide grooves. The guide groove and the guide protrusion guide the lens holding frame 15 so as to be freely movable in parallel. Instead of the guide groove, a guide mechanism may be constituted by a guide bar and a slider slidably fitted in the guide bar.

Although not shown, a forceps channel, an air intake / suction channel, and the like are provided in the endoscope end portion 11 in parallel with the image fiber. And
A cover glass for sealing is provided in front of the objective lens group L1.

[0007] An electromagnetic actuator is connected to the fixed barrel 17 and the lens holding frame 15 as driving means for moving the lens holding frame 15 in parallel along the optical axis O. The electromagnetic actuator according to the present embodiment includes a fixed lens barrel 1
7 includes a pair of electromagnetic actuator stators 21 extending parallel to the optical axis O and a pair of electromagnetic actuator movers 31 mounted on the lens holding frame 15.

Each of the pair of electromagnetic actuator stators 21 has a flat plate-shaped substrate 22 and a plurality of coils 23 linearly arranged on the substrate 22 at a first pitch. The pair of electromagnetic actuator movers 31 are respectively
A flat substrate 32 and a first coil 23 on the substrate 32
A plurality of magnetic bodies 33 are arranged on a straight line parallel to the optical axis O at a second pitch 1.5 times the pitch of FIG.
reference). The coil 23 can exert a stronger magnetic force by being wound around an iron core.

A plurality of coils 23 of the pair of electromagnetic actuator stators 21 are energized from a power supply circuit 41 connected to an extracorporeal operation section of the endoscope. The energization is controlled by the control circuit 43 which has received an operation signal from the operation switch 45 (see FIG. 3). The electromagnetic actuator stator 21 of this embodiment has three phases. That is, three adjacent coils 23 are set as one set, and the first, second, and third coils 23 of each set are energized and controlled for each of the sets.

The electromagnetic actuator stator 21 (coil 2
The energization control and operation state of 3) will be described with reference to FIG. (A) shows a state in which the objective lens group L1 is held at the first position. In the figure, assuming that the left end is the first coil 23, the first coil 23 of each group is energized. In the figure, the coil 23 indicated by the symbol N is energized positively, and the coil 23 indicated by the symbol S is energized in reverse (negative). In this energized state, each energized coil 23 is provided with an electromagnetic actuator mover 31.
The odd-numbered magnetic body 32 is attracted, and the substrate 32, and thus the objective lens group L1, is held at the first position by the attracting force. It should be noted that the direction of energization to the coil 23 may be the same in any direction. If the magnetic body 32 is a permanent magnet, the current is supplied in the direction of the N pole or S pole attracting the S pole or N pole.

The objective lens group L1 is moved rightward from the first position (approaching the image fiber 13 incident end face 13i).
When this is done, the power supply to the first coil 23 is cut off, and power is supplied to the third coil 23 (FIG. 4B).
Then, the even-numbered magnetic body 33 of the electromagnetic actuator mover 31 is attracted to the excited third coil 23, so that the objective lens group L1 moves rightward and is held at the second position. (FIG. 4C).

Further, when the objective lens unit L1 is moved rightward (closer to the incident end face 13i), the power supply to the third coil 23 is cut off, and power is supplied to the second coil 23 (FIG. 4D). ). Then, the odd-numbered magnetic bodies 33 of the electromagnetic actuator mover 31 are attracted to the excited second coils 23, respectively, so that the objective lens group L
1 moves rightward and is held in a third position (FIG. 4).
(E)).

By controlling the energization of the coil 23 as described above, the objective lens group L1 is connected to the image fiber 13
Can be approached in 0.5 pitch units. Conversely, when the objective lens L2 is separated from the image fiber 13, it can be easily understood that the separation can be performed in units of 0.5 pitch by reversing the energizing sequence. In the present embodiment, the ratio of the first pitch of the coil 23 to the second pitch of the magnetic body 33 is set to 2: 3, but the ratio of the pitch is not limited to this. By changing the ratio of the pitch between the coil 23 and the magnetic body 33 in this manner, it is possible to control the movement at a pitch shorter than the pitch between the coil 23 and the magnetic body 33. For example, if the pitch ratio between the coil 23 and the magnetic body 33 is 3: 4, the movement can be controlled at a 1/3 pitch.

As described above, in this embodiment, when the operation switch 45 is operated, the objective lens group L1 is moved by the electromagnetic actuator to the incident end face 13i of the image fiber 13.
As it moves in and out step by step, the near point and far point can be easily adjusted, and the endoscope end can be enlarged and observed closer to the affected area, or separated from the affected area. Can be observed in focus.

Although the embodiment applied to the endoscope provided with the image fiber has been described above, the present invention can also be applied to a rigid endoscope and an electronic endoscope using a CCD image pickup device instead of the image fiber. . In the illustrated embodiment,
Although a pair (two) of electromagnetic actuator stators and movers are provided with the objective lens group interposed therebetween, one or two to four electromagnetic actuators may be provided. The electromagnetic actuator may be a linear stepping motor. Although the electromagnetic actuator is manually driven and controlled, a defocus is obtained based on an image input through an image fiber or an image input through an image pickup device in an electronic endoscope. To drive the electromagnetic actuator based on the above.

[0016]

According to the first aspect of the present invention, the objective lens group of the endoscope is moved back and forth along the optical axis by the electromagnetic actuator which moves linearly in a stepwise manner. Thus, a small focus adjusting mechanism can be provided. Since the pitch of the coil of the electromagnetic actuator and the pitch of the magnetic material are different, step control at a pitch shorter than those pitches is possible.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an outline of a distal end portion of a body insertion portion of an endoscope according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an outline of the electromagnetic actuator of the embodiment of FIG. 1;

FIG. 3 is a block diagram showing a configuration related to drive control of the electromagnetic actuator.

FIG. 4 shows an operation sequence of the electromagnetic actuator.
It is a figure which shows in (A), (B), (C), (D), and (E) different states.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Front-end | tip part of a body insertion part 13 Image fiber 15 Lens holding frame 17 Fixed lens-barrel 21 Electromagnetic actuator stator 23 Coil 31 Electromagnetic actuator mover 33 Magnetic body L1 Objective lens group

Claims (5)

[Claims] 1. A focus adjusting device for moving an objective lens group of an endoscope along an optical axis, a guide member for movably guiding the objective lens group parallel to the optical axis, and the objective An electromagnetic actuator for moving the lens group along the optical axis, the electromagnetic actuator comprising a coil fixed at a fixed pitch of the endoscope and arranged at a first pitch along the optical axis. An electromagnetic actuator stator, and a magnetic body fixed along the optical axis at a second pitch different from the coil and fixed to the lens frame so as to be close to and facing the electromagnetic actuator stator. A focusing device for an endoscope. 2. The ratio of the first and second pitches is 2: 3.
The focus adjusting device for an endoscope according to claim 1, wherein: 3. The endoscope according to claim 1, wherein the objective lens group is held by a lens holding frame, and the lens holding frame is guided by a guide member so as to be able to move in parallel along the optical axis. Mirror focusing device. 4. The focus adjusting device for an endoscope according to claim 1, wherein the electromagnetic actuator is a linear stepping motor. 5. The electromagnetic actuator according to claim 1, wherein the electromagnetic actuator is driven stepwise by an operation switch and a power supply provided in an extracorporeal operation unit of the endoscope, and moves the objective lens group stepwise. 3. The focus adjusting device for an endoscope according to claim 1.