JPH10216077A - Endoscope device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide observation of a close view and a distant view by use of a fixed focus type objective optical system. SOLUTION: A refraction factor changing element 3 to change a focusing position of an objective lens 1 is provided between an objective lens 1 having a tiip rigid part and a CCD image sensor 2. This refraction factor changing element 3 is formed of nematic liquid crystal member 3b enclosed between two glass substrates of which surface is coated with transparent conductive film, so an orientation direction of liquid crystal molecules is changed to change a refraction factor by supply of a specified voltage or more to each transparent conductive film. An optical path length (focusing position) of the objective lens 1 can thus be changed in stages, thereby observation of a close view and a distant view can be provided in spite of use of a fixed focus type objective optical system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope apparatus suitable for use in an electronic endoscope apparatus, a fiberscope apparatus, a gastric camera apparatus and the like used for medical or industrial purposes.

[0002]

2. Description of the Related Art In recent years, an electronic endoscope apparatus mainly used for medical purposes has been known. The electronic endoscope apparatus is configured to perform, for example, a guiding tube inserted into a human body, a rigid distal end portion provided at the distal end of the guiding tube to capture an image of a lesion, and perform imaging of a lesion. And an operation unit that performs operations such as angle adjustment and focusing of the one-end rigid part, and supplies power to a CCD image sensor (solid-state imaging device) and the like, and also processes an imaging signal of a lesion part imaged by the rigid part at the tip. And a connector section for supplying the power to the connector.

[0003] In the case of, for example, examining the inside of the stomach using such an electronic endoscope apparatus, a rigid tip is inserted into the stomach via the oral cavity and the esophagus. A light guide is provided in the hard distal end portion, and light is irradiated to a lesion or the like via the light guide. Further, the distal end rigid portion is configured to bend up, down, left, and right from a predetermined location in accordance with the operation of the operation portion. For this reason, the doctor adjusts the angle of the rigid distal end portion so that an image of a lesion or the like can be taken by operating the operation unit.

The light passing through the light guide irradiates a lesion or the like, and the imaging light formed by the light guide passes through an objective lens provided in the distal end rigid portion, through the CCD in the distal end rigid portion.
An image is formed on the image sensor. The CCD image sensor forms an imaging signal by performing photoelectric conversion processing on the imaging light, and supplies the imaging signal to a processor via a signal line, an operation unit, and a connector unit provided in the guide tube. Thus, a captured image of a lesion or the like can be displayed on the display screen of the monitor device via the processor.

[0005]

However, the conventional electronic endoscope apparatus includes an objective lens and a CCD provided in a rigid portion at the distal end.
Since an objective optical system of a fixed focus type is provided as an objective optical system including an image sensor or the like, there is a problem that an observation range is narrow.

That is, if the focus position of the objective optical system is set to be fixed to the near view in order to enable magnified observation by approach, the distant view will be blurred, and if the focus position is set to be fixed to the distant view, the close view will be obtained. Bokeh, clinically troublesome.

This problem is caused by the F value of the objective lens (F number: F
By increasing the value of (number), the depth of focus (depth of field) can be increased to some extent because it increases. However, when the F value is increased, the square of the F value sacrifices brightness, which is not preferable.

[0008] In the case of a fixed focus lens, the above-mentioned problem can be solved by providing a stepless focusing adjustment mechanism such as a normal camera lens. Since the lens has a short focal length, it is difficult to form a stepless focusing adjustment mechanism. In addition, since the stepless focusing adjustment mechanism itself becomes large, the provision of this mechanism increases the outer diameter of the tip rigid portion and the length of the tip rigid portion. It is not suitable for providing in an endoscope device.

Further, if a zoom lens or a variable focus lens is used in place of the fixed focus type objective optical system, magnified observation and the like can be performed without approaching the zoom lens. Since a large number of lenses having a large outer diameter are required as compared with the fixed focus lens, and the length of the lens system is longer, when provided in an electronic endoscope device, the outer diameter of the tip rigid portion increases and the tip rigid portion length increases. The problem of lengthening occurs.

Further, the zoom lens has a drawback in that the depth of focus (depth of field) becomes narrow at the time of magnifying observation, so that the observable range is narrowed, and it becomes difficult to operate the scope.

For these reasons, it is not suitable to provide a zoom lens in an electronic endoscope device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made without increasing the outer diameter or the like of the tip rigid portion.
In addition, without increasing the length of the rigid portion at the distal end, a simple structure can be used while using a fixed-focus type objective optical system to provide a close-up view.
It is an object of the present invention to provide an endoscope apparatus capable of observing a distant view.

[0013]

In order to solve the above-mentioned problems, an endoscope apparatus according to the present invention comprises an objective lens for forming an optical image of a subject, and an optical image formed by the objective lens. And an optical path length varying means for varying an optical path length of an optical image from the objective lens.

The “capturing means” is, for example, an imaging light captured via an objective lens provided on one end side,
There is a so-called fiberscope, in which light is guided to the other end by an optical fiber, and the light is directly observed with an eye through a magnifier or the like. Alternatively, for example, a so-called gastric camera apparatus that maps imaging light taken in through an objective lens onto a film or the like is used. Moreover,
For example, photoelectric conversion means such as a solid-state imaging device (CCD image sensor) and an imaging tube for converting an optical image captured via an objective lens into an electrical imaging signal and outputting the signal are listed.

The "optical path length varying means" includes a refractive index varying means for changing a refractive index to change a focusing position of a subject of an objective lens, or a capturing means, and a solid-state image pickup device. Means for changing the focus position of the object of the objective lens by sliding the object in the optical axis direction is provided.

In such an endoscope apparatus, the "optical path length varying means" changes the focus position of the objective lens. This allows
Despite the use of a fixed focus type objective optical system, it is possible to observe a near view and a distant view. In addition, since it can be realized with a simple configuration only by providing the optical path length varying means, it is possible to prevent an inconvenience of increasing the outer diameter of the rigid portion at the tip and increasing the length of the rigid portion at the tip.

In order to variably control the observation area, it is not necessary to forcibly increase the F value of the objective lens.
Increasing the value can prevent the disadvantage of sacrificing the brightness of the imaging light.

Further, since a fixed focus type objective optical system is used as a basis, observation can be performed even within a range of a depth of focus based on each in-focus position of a near view and a distant view, and observation in a wider area is possible. Can be made possible.

Further, by switching the focus position stepwise, it is possible to simplify the switching operation between the near view observation and the distant view observation, and to reduce the operation burden and the like on the operator.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an endoscope apparatus according to the present invention will be described below in detail with reference to the drawings.

The endoscope device according to the present invention can be applied to a medical electronic endoscope scope. FIG. 1 is a diagram illustrating an objective optical system provided in a rigid distal end portion of an electronic endoscope according to a first embodiment of the present invention.

The objective optical system shown in FIG. 1 includes an objective lens 1 for capturing image light of a subject and a CCD image sensor for receiving the image light captured by the objective lens 1 and converting the received image light into an image signal as an electric signal. 2 and objective lens 1
And the CCD image sensor 2, the refractive index of which is changed by ON / OFF control of the voltage.
And a variable-refractive-index element 3 for changing the focus position (optical path length) of the imaging light via the optical element.

The variable refractive index element 3 includes two glass substrates 3
A nematic liquid crystal member 3b of a mixed system of cyanobiphenyl is sealed and formed between a (or a plastic substrate). A transparent conductive film for voltage supply is provided on the surface (outer surface side) of each glass substrate 3a, and a film of polyimide or the like for aligning liquid crystal molecules is coated on the surface of the transparent conductive film. . Further, the liquid crystal molecules of the liquid crystal 3b have a homogeneous alignment that has been subjected to a friction treatment (rubbing) such that the alignment surface thereof is substantially parallel to the glass substrate 3a.

The liquid crystal 3b used in the variable refractive index element 3 may be, for example, a mixed liquid crystal of cyanophenyl ester, a mixed liquid crystal of cyanophenylpyrimidine, A phenylcyclohexane-based mixed liquid crystal or the like can be used. In addition, the alignment of the liquid crystal molecules may be, for example, homeotropic alignment, pretilt alignment, twist alignment, hybrid alignment, or the like, in addition to the homogeneous alignment.

The variable refractive index element 3 has optical characteristics such that the refractive index decreases when a voltage is applied and increases when no voltage is applied. The objective optical system is provided with an objective lens 1 such that a focus position of a distant view via the variable refractive index element 3 is formed on the CCD image sensor 2 when no voltage is applied to the variable refractive index element 3, that is, a so-called objective lens. It is a fixed focus type.

FIG. 2 is a view showing the appearance of an electronic endoscope according to the first embodiment in which such an objective optical system is provided in a rigid end portion.

In FIG. 2, an electronic endoscope scope supplies power to an operation unit 11 operated by an operator and an electronic endoscope scope, and outputs an imaging signal by imaging to, for example, a magnetic disk recording / reproducing apparatus or a monitor. It has a connector terminal 12 to be supplied to an external device such as a device, and a guiding tube 13 inserted into a human body.

The operating section 11 and the connector terminal 12 are connected by a universal cord 19 via a tapered tube 18. In this universal code 19,
A power cord for supplying power, a signal line for supplying an imaging signal to an external device, and the like are housed.

The guiding tube 13 is connected to the operating section 11 via a tapered tube 18, and the distal end thereof is a rigid distal end section 19 having the above-mentioned objective optical system.

FIGS. 3A and 3B are views showing a state in which the rigid distal end portion 19 is bent in accordance with the operation of the surgeon. As shown in FIGS. 3A and 3B, the distal end hard portion 19 is
It can be bent up, down, left and right in accordance with the operation of the operation unit 11. For this reason, the angle can be changed almost freely after the rigid tip portion 19 is inserted into the body, and it is possible to observe a lesion or the like at an arbitrary angle.

FIG. 4 is a view showing the distal end surface of the distal end rigid portion 19.

In FIG. 4, the distal end surface 19a of the distal end rigid portion 19 sends out an air supply port 21 for supplying air, a water supply port 22 for supplying water, and a forceps for extracting a lesion or the like. Forceps port 23, an illumination lens 24 for irradiating light to a lesion or the like, and imaging light that is reflected light of the light emitted through the illumination lens 24 is taken in, and is taken into the refractive index variable element 3 And an objective lens 1 for irradiating the CCD image sensor 2 with the objective lens 1.

In the guiding tube 13, an air supply tube connected to the air supply port 21, a water supply tube connected to the water supply port 22, a forceps tube connected to the forceps port 23, and a light Handle, a power supply line for supplying a power supply voltage to the variable refractive index element 3, and a CCD
A CCD line for driving the image sensor 2 and supplying an image signal picked up by the CCD image sensor 2 to an external device, and a wire cable for adjusting the angle of the tip rigid portion 19 up, down, left and right are housed therein. I have.

Next, the operating section 11 is provided with an angle knob 14 for changing the angle of the distal end rigid portion 19 and other operation keys for performing operations such as air supply and water supply. Key group 15 and distal end surface 19a of distal rigid portion 19
And a forceps port 17 for inserting forceps sent out through the forceps port 23 of FIG. The operation keys 15 include
A focus position adjustment key 16 for controlling on / off of a voltage supplied to the refractive index variable element 3 is provided. When the focus position adjustment key 16 is turned on and off, the voltage supplied to the variable refractive index element 3 is turned on and off, and the focus position of the objective lens 1 is changed.

Next, the operation of the electronic endoscope having the above-described configuration according to the first embodiment will be described.

For example, when examining the stomach with this electronic endoscope, the connector terminal 12 is first connected to the processor body, and the rigid tip portion 19 is inserted into the stomach via the human oral cavity and esophagus. The light of the xenon lamp, which is turned on and driven in the operation unit 11 by the power supplied from the processor main body via the connector terminal 12, is guided to the illumination lens 24 via the fiber handle to the tip rigid portion 19. The inside of the club is illuminated. The reflected light by this is converged by the objective lens 1 shown in FIG.

Here, when the focus position adjusting key 16 shown in FIG. 2 is turned off by the operator, no voltage is supplied to the variable refractive index element 3, so that the refractive index of the variable refractive index element 3 is This makes it possible to observe a distant view at the in-focus position FP2 of the objective lens 1 shown in FIG. 1 which is a fixed focus. The imaging light of the distant view is applied to the CCD image sensor 2 via the variable refractive index element 3.

Upon receiving the imaging light, the CCD image sensor 2 performs a photoelectric conversion process on the imaging light into an imaging signal, which is an electric signal, and converts the imaging signal into the processor body via the CCD line, the operation unit 11 and the connector terminal 12. To supply. A monitor device is integrally incorporated in the processor body. The processor main body performs a predetermined process on the image signal and supplies the image signal to the monitor device. Thereby, the state inside the stomach (in this case, a distant view in the stomach) currently being imaged by the distal end rigid portion 19 can be displayed on the display screen of the monitor device.

Next, the surgeon observes the inside of the stomach displayed on the display screen of the monitor device while operating the operation unit 11.
Is operated by the angle knob 14 provided in the. When the angle knob 14 is operated, this driving force is transmitted to the distal end rigid portion 19 via the wire cable, and the distal end rigid portion 19 is transmitted.
However, it bends up, down, left and right according to the operation. Thereby, the angle of the distal end rigid portion 19 can be adjusted substantially freely, and the inside of the stomach can be observed throughout.

Next, when switching from such distant view observation to near view observation, the operator turns on the focus position adjustment key 16 shown in FIG. Thereby, a voltage is supplied to the refractive index variable element 3. As this voltage, for example, a power supply voltage of 2 V to 3 V (FIG. 1)
Is indicated by reference numeral 4 as a power supply voltage V. ) Is supplied.

Since the power supply voltage is a weak voltage of 2 V to 3 V, even if a leak occurs, there is no adverse effect such as electric shock on the human body.

The dielectric constant of the nematic liquid crystal member 3b is different between the major axis direction of the liquid crystal molecules and the direction orthogonal to the major axis direction, and the difference in the dielectric constant shows a positive value. . When a voltage equal to or more than a predetermined voltage is supplied to the transparent conductive film of the refractive index variable element 3, the liquid crystal 3b is oriented in such a direction that the electric energy is reduced, that is, the major axis direction of the liquid crystal molecules is in the direction of the electric field. Upon receiving such a force, the liquid crystal molecules change from a direction parallel to the glass substrate 3a to a direction perpendicular thereto.

As a result, the refractive index becomes smaller when a voltage is applied than when no voltage is applied. As shown by a dotted line in FIG. As shown by the solid line, it can be changed to "FP1" which is the focus position of the foreground.

For this reason, the imaging light of the foreground can be focused on the CCD image sensor 2 via the refractive index variable element 3, and the foreground in the stomach can be observed.

Specifically, for example, when the focal length is "1 mm"
And the refractive index (non) at the time of voltage application is “1.
51 "and a refractive index (noff) of 1.7 when no voltage is applied.
The distance (d1) from the center of the objective lens 1 to the variable refractive index element 3 is set to “0.61” using the variable refractive index element 3 of “1”.
mm ", and the thickness (d2) of the variable refractive index element 3 is set to" 1.
When the voltage is set to "00 mm", the air-equivalent lengths are obtained by the arithmetic expressions shown in the following equations (1) and (2) when a voltage is applied and when no voltage is applied.

[0046]

## EQU00001 ## Air-equivalent length when voltage is applied = d1 + d2 / non = 0.61 + 1.00 / 1.51 = 1.140 (Equation 1) Air-equivalent length when no voltage is applied = d1 + d2 // noff = 0.61 + 1.00 / 1.71 = 1.078 (Expression 2)

For this reason, the focus position F of the foreground when the voltage is applied
P1 is 8 mm, and the focus position FP2 of the distant view when no voltage is applied is 14 mm (see FIG. 6).

That is, when no voltage is supplied to the transparent conductive film (when no voltage is applied), the refractive index variable element 3 has a distant view resolution characteristic as shown by a dotted line in FIG. When a voltage is applied (when a voltage is applied), the image has a close-up view resolution characteristic as indicated by a dashed line in FIG. For this reason, as shown by a solid line in FIG. 5, a resolution characteristic is obtained by extracting the envelope of the overall resolution characteristic formed by superimposing the resolution characteristic of the distant view and the resolution characteristic of the near view. Will be provided.

As is apparent from the above description, the electronic endoscope scope according to the first embodiment controls the power supply voltage supplied to the refractive index variable element 3 on and off.
The focus position of the fixed focus type objective optical system can be variably controlled. For this reason, the captured image displayed on the display screen of the monitor device can be in a desired observation area, and more accurate medical examination and the like can be performed.

In order to variably control the observation area, it is not necessary to forcibly increase the F value of the objective lens.
Increasing the value can prevent the disadvantage of sacrificing the brightness of the imaging light.

Further, since a fixed focus type objective optical system is used as a basis, observation can be performed even within the range of the depth of focus based on the in-focus positions of the near view and the distant view, and observation in a wider area is possible. Can be made possible.

The switching of the focus position is performed stepwise (in this case, two steps), so that the operation of switching between the near view observation and the distant view observation can be simplified, and Operation burden and the like can be reduced.

Further, since the focus position of the objective lens 1 can be electrically variably controlled by the variable refractive index element 3, the objective lens or the C lens is used to variably control the focus position.
No mechanical structure such as a slide mechanism of the CD image sensor is required. Therefore, the diameter of the distal end hard portion 19 can be reduced, and the length of the distal end hard portion 19 can be shortened. Further, since the wire cable connected to the slide mechanism or the like can be omitted, the diameter of the guiding tube 13 can be reduced. Therefore, the burden on the patient who inserts the distal end rigid portion 19 can be greatly reduced.

The voltage supplied to the variable refractive index element 3 necessary for variably controlling the focus position of the objective lens 1 is 2
Since the voltage is as low as V to 3 V, even if there is a leak, the applied voltage does not adversely affect the human body, and the reliability of the electronic endoscope can be improved.

Further, when liquid crystal is used as the variable refractive index element 3, even if the liquid crystal enclosure is damaged, the liquid crystal is not a complete liquid. The effect on built-in components can be reduced.

Next, an electronic endoscope according to a second embodiment of the present invention will be described.

In the electronic endoscope according to the first embodiment, the voltage supplied to the variable-refractive-index element 3 is controlled to be on / off so that the in-focus position of the objective lens 1 can be set to two.
Although the electronic endoscope according to the second embodiment continuously varies the voltage supplied to the variable refractive index element, the focusing position of the objective lens 1 is changed. Are also continuously variably controlled.

The electronic endoscope according to the second embodiment uses the variable refractive index element 3 as shown in FIG.
Alternatively, a nematic liquid crystal member having a lens structure as shown in FIG. 2B is provided, and the other parts are substantially the same as those of the electronic endoscope according to the first embodiment. In the description, the nematic liquid crystal member having the lens structure will be referred to, and the description of the other portions will be omitted.

That is, as shown in FIG. 7A, a nematic liquid crystal member having a lens structure provided between the objective lens 1 and the CCD image sensor 2 is composed of a plano-concave lens 31 having an outer surface coated with a transparent conductive film. A glass substrate 32 having an outer surface coated with a transparent conductive film is adhered via a spacer 34, and a nematic liquid crystal member 33 of homogeneous orientation is sealed therein.

In this case, the operating section 11 is provided with a focus position variable switch, and when the focus position variable switch is turned on, a built-in arithmetic circuit (CPU) supplies a signal to each transparent conductive film. Voltage (power supply 35) is continuously variably controlled.

Thus, the nematic liquid crystal member 3
3 can be continuously controlled, and the in-focus position of the objective lens 1 can be continuously changed by operating the nematic liquid crystal member as a concave lens. Therefore, it is possible to focus on a position desired by the operator, and it is possible to observe a lesion or the like at a more preferable focus position.

Next, as a modification of the electronic endoscope according to the second embodiment, as shown in FIG. 7B, a nematic liquid crystal member having the above-mentioned lens structure is provided on the outer surface side with a transparent conductive film. Is bonded to a glass substrate 42 coated with a transparent conductive film on the outer surface side via a spacer 44, and a homogeneous alignment nematic liquid crystal member 43 is sealed therein. Good. In this case, the voltage (the power supply 45) supplied to each of the transparent conductive films is continuously variably controlled in accordance with the operation time of the in-focus position variable switch, and the nematic liquid crystal member is operated as a convex lens so as to operate the objective lens 1. The focus position can be changed continuously.

As is clear from the above description, the electronic endoscope scope according to the second embodiment and the electronic endoscope scope according to the modified example are provided with a nematic liquid crystal member having a lens structure, By continuously variably controlling the voltage supplied to the film, the focus position of the objective lens 1 can be continuously variably controlled. For this reason, in addition to being able to observe a lesion or the like at a more preferable focus position,
The same effects as those of the electronic endoscope according to the first embodiment can be obtained.

As a focus position variable switch, a rotary switch for variably controlling a voltage to be supplied according to a rotation angle, a joystick for variably controlling a voltage to be supplied according to an operation angle, a plurality of stages can be switched by one. A possible switch, a switch for variably controlling the voltage according to the pressing time, or the like may be provided. This may be determined by the operator's preference or operability.

Next, an electronic endoscope according to a third embodiment of the present invention will be described.

In the electronic endoscope according to the second embodiment described above, a nematic liquid crystal member having a lens structure is provided as the variable refractive index element 3, but in the liquid crystal member using the plano-concave lens 31, the center is not provided. The liquid crystal member using the plano-convex lens 41 has a problem that the thickness of the liquid crystal layer in the peripheral portion increases.

For this reason, in the electronic endoscope according to the third embodiment, the lens portion formed by the liquid crystals 33 and 43 has a Fresnel structure, and the liquid crystal layer is formed to be practically thin.

The electronic endoscope according to the third embodiment has the same structure as the electronic endoscope according to the second embodiment except that the lens portion of the nematic liquid crystal member having the lens structure has a Fresnel structure. Since it is substantially the same as the endoscope, the description thereof will refer to the nematic liquid crystal member having the lens portion having the Fresnel structure, and the description of the other portions will be omitted.

That is, the nematic liquid crystal member provided in the electronic endoscope according to the third embodiment includes, for example, a Fresnel concave lens made of acrylic, whose surface is coated with a transparent conductive film, and an ITO glass substrate (In2). O3
: Sn film) through a spacer having a predetermined thickness, and a nematic liquid crystal member having a homogeneous orientation is sealed therebetween. Then, at the time of driving, the voltage supplied to the transparent conductive film is continuously varied as described above. Thereby, the focus position of the objective lens 1 can be continuously variably controlled.

In such a nematic liquid crystal member, since the lens portion has a Fresnel structure, the thickness of the central portion can be effectively reduced, and the alignment force of the liquid crystal molecules of the nematic liquid crystal member can be increased. Therefore, the response characteristics can be improved to approximately the square of the supply voltage, and the recovery time can be made substantially constant regardless of the supply voltage.

Here, the focusing position variable characteristic of the liquid crystal lens is effective only for a so-called extraordinary light component. For this reason, in the configuration of the electronic endoscope according to each of the above-described embodiments, there is no problem in use. However, if it is attempted to extract only the light component whose focus position has been changed, the liquid crystal lens and the CCD image It is necessary to provide a polarizing plate between the sensor 2 and the sensor 2 so as to transmit only the extraordinary light component. When this polarizing plate is provided, the transmittance of the entire refractive index variable element 3 is 30% to 4%.
A problem of falling to 0% occurs.

For this reason, in the electronic endoscope according to the fourth embodiment, as the variable refractive index element 3, two liquid crystal lenses having the same characteristics are used, and the alignment directions of the liquid crystal molecules are orthogonal to each other. Are used in such a way as to overlap each other. Then, the liquid crystal lens is driven by continuously supplying a voltage.

As a result, each of the liquid crystal members transmits one of the ordinary light and the extraordinary light. Therefore, it is necessary to improve the overall transmittance to 80% or more and to use a polarizing plate. Only the light component whose focus position has been changed can be extracted.

Next, each liquid crystal member provided in the electronic endoscope scope according to each of the above-described second to fourth embodiments supplies the predetermined voltage or more to focus the objective lens 1. The position can be variably controlled. However, when the supply voltage approaches the saturation voltage of each liquid crystal member, a non-linear characteristic in which the change of the focus position gradually becomes gentle is exhibited.

For this reason, in the electronic endoscope scope according to the fifth embodiment of the present invention described below, the non-linear characteristics of each liquid crystal member are compensated.

That is, in the electronic endoscope according to the fifth embodiment, the refractive index variable element 3 is
Homogeneous alignment guest-host (G) showing a shape change similar to the focusing position variable characteristic curve in a liquid crystal lens
H) It has a liquid crystal member, and an inverse function generation circuit that drives the liquid crystal member by forming an inverse function characteristic using the transmitted light intensity characteristic of the liquid crystal member.

The inverse function generation circuit includes a light intensity detection circuit for detecting the light intensity of the imaging light transmitted through the liquid crystal member, and a liquid crystal member based on the light intensity of the imaging light detected by the light intensity detection circuit. And a driving circuit for driving the liquid crystal member.

When driving the liquid crystal member, the inverse function generating circuit continuously and variably controls the voltage supplied to the liquid crystal member so that the light intensity of the imaging light detected by the light intensity detection circuit becomes constant. I do.

As a result, the non-linear characteristics of the liquid crystal member can be compensated for substantially linear characteristics, and the operability of the electronic endoscope can be improved.

By optimizing the dye concentration and the like of the guest / host liquid crystal member, it is possible to perform better non-linear characteristic compensation.

Next, in the electronic endoscope according to each of the above-described embodiments, a nematic liquid crystal member is used as the liquid crystal of the variable refractive index element 3. However, the electronic endoscope according to the sixth embodiment described below will be described. Like such an electronic endoscope scope,
An ionic liquid may be sealed instead of the nematic liquid crystal member.

That is, the refractive index variable element 3 provided in the electronic endoscope according to the sixth embodiment.
Means that the front and back surfaces each have a predetermined radius of curvature.
A glass member, a cover member for sealingly connecting each glass member so as to cover an outer peripheral portion of each glass member when the two glass members are butted to form a hollow portion, and this cover member. An anode electrode and a negative electrode provided so as to oppose each other on the outer peripheral portion of each glass member covered with, and an ionic liquid sealed in a hollow portion formed by abutting each glass member. It is configured.

Examples of the ionic liquid include sodium nitrate ion (Tl + NO3-) and cesium nitrate ion (Cs
+ An aqueous solution such as NO3-) is enclosed.

Such a variable refractive index element 3 has a large refractive index before a voltage is supplied through each electrode. Further, when the voltage is gradually supplied, each ion in the ionic liquid is attracted to each electrode having a different polarity according to the supplied voltage value, and the ions present at the central portion of the refractive index variable element 3 gradually decrease. , The refractive index gradually decreases.

As a result, the focus position of the objective lens 1 can be variably controlled, and the same effects as those of the electronic endoscope according to each of the above embodiments can be obtained.

Incidentally, a continuously variable voltage is supplied to the variable refractive index element 3 in which liquid ions are sealed provided in the electronic endoscope according to the sixth embodiment to supply the objective voltage. Although the refractive index of the lens 1 is variably controlled, the voltage may be controlled to be on or off at a voltage higher than a predetermined value. Thus, similarly to the electronic endoscope according to the above-described first embodiment, the focus position of the objective lens 1 can be variably controlled in two stages (when a voltage is applied and when no voltage is applied).

In the above description, the electronic endoscope was used for electrically changing the optical path length (focusing position). However, the electronic endoscope according to the seventh to twelfth embodiments of the present invention described below. The endoscope is configured to change the optical path length of a fixed-focus type objective optical system stepwise by a mechanical configuration.

In the description of the electronic endoscope according to the seventh to twelfth embodiments, the same portions as those of the above-described electronic endoscope according to the first embodiment have the same operations. The reference numerals are used, and the detailed description is omitted.

First, FIG. 8 is a sectional view of an objective optical system provided in the distal end rigid portion 19 of the electronic endoscope according to the seventh embodiment of the present invention.

In FIG. 8, the rigid distal end portion 19 has a rigid distal end portion main body 51 having a substantially hollow cylindrical shape, and the objective lens 1 is provided on the distal end surface 19a. Also,
A prism 57 that reflects the optical path of the imaging light captured through the objective lens 1 at an angle of, for example, 45 degrees is provided in the hollow interior.

The prism 57 is fixed on a flat glass plate 58. Further, the imaging light reflected by the prism 57 is applied to the flat glass plate 58.
The CCD image sensor 2 is provided at a position where light is accurately received through the CCD 8.

On the surface of the glass plate 58 on which the CCD image sensor 2 is provided, wiring patterns such as terminals and lines for supplying power and a control clock to the CCD image sensor 2 are deposited. Therefore, the respective terminals of the CCD image sensor 2 and the respective terminals formed on the glass plate 58 are aligned and fixed to each other, so that electrical connection can be easily performed. Further, the imaging signal output line 59 and the like are connected to terminals formed on the glass plate 58.

Next, a wire cable 60 is fixed to the back surface of the reflecting surface of the imaging light of the prism 57 by an adhesive member 61. The wire cable 60 has a rigid distal end portion 1.
9 is connected to a through-hole 51b provided in a rear end face 19b opposed to the front end face 19a through a hollow interior, and a focusing position variable knob provided in the operation unit 11 through a guiding tube 13. I have.

[0094] A wire guide 62 is wound around the wire cable 60, so that the guide tube 1 is provided.
The movement of the wire cable 60 in the inside 3 or the like is regulated.

Glass plate 58 to which prism 57 is fixed
The both ends are sandwiched between the flat holding members 52 and 53 so as to be movable in the extending direction of the distal end rigid portion 19. When the surgeon rotates the in-focus position variable knob, the force in the extending direction of the distal end rigid portion 19 is transmitted to the prism 57 via the wire cable 60, and the prism 57 is moved to the distal end rigid portion 19. Are slid in the direction of the front end surface 19a and in the direction of the rear end surface 19b.

More specifically, each holding member 52, 53
By holding the glass plate 58 between the end portion 58a of the glass plate 58 and the contact portion 53a of the holding member 53, and the other end portion 58b of the glass plate 58 and the contact portion 53a of the holding member 53 Between them, a sliding hollow portion 55 corresponding to the thickness of the glass plate 58 is formed, and the glass plate 58 slides within the range of the sliding hollow portion 55.

Further, the objective optical system is fixed so as to focus on a distant view on the CCD image sensor 2 when one end portion 58a of the glass plate 58 comes into contact with the contact portion 53a of the holding member 53. It is focused. In this objective optical system, the other end 58b of the glass plate 58 is
Is adjusted so as to focus on the near image on the CCD image sensor 2 when it comes into contact with the contact portion 53a. That is, in this objective optical system, the focal points of the distant view and the near view can be changed stepwise in two steps by such a mechanical configuration.

Next, the seventh embodiment having such a mechanical structure will be described.
The operation of the electronic endoscope according to the embodiment will be described.

First, when observing a distant view, the operator rotates the focus position variable knob provided on the operation unit 11 in the first rotation direction. Thereby, the wire cable 6
The force at the time of compression (the force in the direction of the distal end face 19 a of the distal end rigid portion 19) is transmitted to the prism 57, and the glass plate 58 is moved until one end 58 a of the glass plate 58 contacts the contact portion 53 a of the holding member 53. Slide.

As described above, this objective optical system focuses a distant view on the CCD image sensor 2 when the one end 58a of the glass plate 58 comes into contact with the contact portion 53a of the holding member 53. ing. For this reason, when the focus position variable knob is rotated in the first rotation direction, it is possible to observe a distant view.

Next, when observing the near view, the surgeon adjusts the focus position variable knob provided on the operation unit 11 in the second rotation direction opposite to the above-described first rotation direction. Rotate to. As a result, a force for pulling the wire cable 60 (a force in the direction of the rear end face 19b of the distal end rigid portion 19) acts,
Until the other end 58b of the glass plate 58 contacts the contact portion 53a of the holding member 53 via the prism 57, the glass plate 58
Slides.

As described above, this objective optical system focuses the foreground on the CCD image sensor 2 when the other end 58b of the glass plate 58 contacts the contact portion 53a of the holding member 53. Has become. For this reason, when the focus position variable knob is rotated in the second rotation direction, it is possible to observe the near view.

As described above, in the electronic endoscope scope of the seventh embodiment, the glass plate 58 provided with the prism 57 and the CCD image sensor 2 is connected to the distal end surface 19 a of the rigid distal end portion 19 by the wire cable 60. The optical path length (focus position) of the imaging light can be changed stepwise by sliding in the direction and the rear end face 19b direction. Accordingly, substantially the same effects as those of the electronic endoscope according to the above-described first embodiment can be obtained, for example, both the near view and the distant view can be observed.

Next, an electronic endoscope according to an eighth embodiment of the present invention will be described.

In the electronic endoscope according to the eighth embodiment, the same reference numerals are given to portions showing the same operations as those in the electronic endoscope according to the seventh embodiment. A detailed description thereof will be omitted.

In the electronic endoscope scope according to the seventh embodiment, the optical path of the image pickup light taken in by the objective lens 1 is refracted by a predetermined amount by the prism 57, and the image pickup light whose light path is refracted is CCD. The electronic endoscope scope according to the eighth embodiment, which receives light by the image sensor 2, is configured to directly receive the imaging light captured by the objective lens 1 by the CCD image sensor 2. It is.

FIG. 9 is a sectional view of an objective optical system provided in the distal end rigid portion 19 of the electronic endoscope according to the eighth embodiment.

In FIG. 9, the distal end rigid portion 19 has an objective lens 1 inside a distal end rigid portion main body 51 having a substantially hollow cylindrical shape.
The CCD image sensor 2 is provided at a position where the imaging light from the camera is directly and accurately received.

The back surface of the CCD image sensor 2 (the surface opposite to the light receiving surface of the imaging light) is fixed to a glass plate 63 on which a wiring pattern is vapor-deposited. The glass plate 63 and the glass plate 58 are fixed so as to be connected to the wiring pattern.

A wire cable 60 is adhered to the back surface of the glass plate 63 fixed to the CCD image sensor 2 by an adhesive member 61.

The objective optical system is adjusted so that a distant view is focused on the CCD image sensor 2 when one end 58a of the glass plate 58 contacts the contact portion 53a of the holding member 53. It is a fixed focus type. In this objective optical system, the other end 58b of the glass plate 58 is
3 is adjusted so as to focus on the near image on the CCD image sensor 2 when it comes into contact with the third contact portion 53a. In other words, this objective optical system sets the focus positions of the distant view and the near view,
With such a mechanical configuration, it can be changed stepwise in two steps.

Next, an eighth embodiment having such a mechanical structure will be described.
The operation of the electronic endoscope according to the embodiment will be described.

First, when observing the near view, the surgeon rotates the variable focus position knob provided on the operation section 11 in the first rotation direction. Thereby, the wire cable 6
The force at the time of compression (the force in the direction of the distal end surface 19a of the rigid distal end portion 19) at the time of compression is reduced to zero.
The glass plate 58 slides until one end 58a of the glass plate 58 contacts the contact portion 53a of the holding member 53.

As described above, this objective optical system focuses on a distant view on the CCD image sensor 2 when one end 58a of the glass plate 58 contacts the contact portion 53a of the holding member 53. ing. For this reason, when the focus position variable knob is rotated in the first rotation direction, it is possible to observe a distant view.

Next, when observing the near view, the operator adjusts the focus position variable knob provided on the operation unit 11 in the second rotation direction opposite to the above-described first rotation direction. Rotate to. As a result, a force for pulling the wire cable 60 (a force in the direction of the rear end face 19b of the distal end rigid portion 19) acts,
The glass plate 58 slides via the glass plate 63 fixed to the CCD image sensor 2 until the other end 58b of the glass plate 58 contacts the contact portion 53a of the holding member 53.

As described above, this objective optical system focuses the foreground on the CCD image sensor 2 when the other end 58b of the glass plate 58 contacts the contact portion 53a of the holding member 53. Has become. For this reason, when the focus position variable knob is rotated in the second rotation direction, it is possible to observe the near view.

As described above, the electronic endoscope according to the seventh embodiment includes a CCD
By sliding the image sensor 2 in the direction of the front end face 19a and the rear end face 19b of the front end rigid portion 19, the optical path length (focusing position) of the imaging light can be changed stepwise. Accordingly, substantially the same effects as those of the electronic endoscope according to the above-described seventh embodiment can be obtained, for example, both the near view and the far view can be observed.

In the description of the seventh and eighth embodiments, the winding and rewinding of the wire cable 60 is performed by rotating the variable focus position knob.
This may be performed by providing a motor for winding and rewinding the wire cable 60 and controlling the energization state of the motor by a focus position variable switch provided on the operation unit 11.

Next, an electronic endoscope according to a ninth embodiment of the present invention will be described.

In the electronic endoscopes according to the seventh and eighth embodiments, the optical path length in the extending direction of the distal end rigid portion 19 is changed by the wire cable 60. In the electronic endoscope scope according to the embodiment, the optical path length in the extending direction of the distal end rigid portion 19 is changed by using expansion and contraction of the piezoelectric element.

In the electronic endoscope according to the ninth embodiment, the same reference numerals are given to portions showing the same operations as those of the electronic endoscope according to the seventh embodiment. A detailed description thereof will be omitted.

FIG. 10 is a sectional view of an objective optical system provided in the rigid distal end portion 19 of the electronic endoscope according to the ninth embodiment.

In FIG. 10, for example, a cube-shaped prism 65 is fixed to a glass plate 58 to which the CCD image sensor 2 is fixed. This prism 65
The image pickup light taken in by the objective lens 1 is reflected at an angle of, for example, 45 degrees by the reflection film 65a provided on the diagonal line, and is irradiated on the CCD image sensor 2.

Further, the rear surface of the prism 65 (the surface facing the incident surface of the imaging light) and the rear end surface 19b
Is fixed with the piezoelectric element 66 interposed therebetween. A power supply line 67 for supplying a voltage to the piezoelectric element 66 is connected to the operation unit 1 through the through hole 51b in the rear end face 19b and the guide tube 13.
1 is connected to the variable focusing position switch provided in the first unit 1. When an operator turns on the variable focusing position switch, a voltage is supplied to the piezoelectric element 66 via the power supply line 67. Has become.

The piezoelectric element 66 is contracted when no voltage is supplied, and in this contracted state, the contraction force of the piezoelectric element 66 causes the glass plate 58 to move through the prism 65 to the rear end face of the rigid distal end portion 19. The other end portion 58b of the glass plate 58 is brought into contact with the contact portion 53a of the holding member 53 by being pulled in the direction of 19b. In this objective optical system, the other end 58b of the glass plate 58 is
3 is a fixed focus type which is adjusted so as to focus on a near view on the CCD image sensor 2 in a state of contact with the contact portion 53a.

The piezoelectric element 66 expands when a voltage is supplied. In this expanded state, the glass plate 58 is moved through the prism 65 by the expansion force of the piezoelectric element 66 so that the glass plate 58 is hardened. The glass plate 58 is pushed out in the direction of the tip end surface 19a of the holding member 19 so that one end 58a of the glass plate 58 comes into contact with the contact portion 53a of the holding member 53. The objective optical system is configured such that the CCD 58 is moved in a state where one end 58a of the glass plate 58 contacts the contact portion 53a of the holding member 53.
It is adjusted so that a distant view is focused on the image sensor 2.

Next, the operation of the electronic endoscope having the above-described configuration according to the ninth embodiment will be described.

First, when observing the near view, the surgeon turns off the focus position variable switch provided on the operation unit 11. As a result, no voltage is supplied to the piezoelectric element 66 via the power supply line 67, and the piezoelectric element 66 maintains a contracted state.

As described above, when the piezoelectric element 66 is in the contracted state, the glass plate 58 is pulled in the direction of the rear end face 19b through the prism 65 by the contraction force of the piezoelectric element 66, The other end 58 b of the 58 contacts the contact portion 53 a of the holding member 53. Then, in this state, the objective optical system is adjusted so as to focus on a near view on the CCD image sensor 2.

For this reason, by turning off the focus position variable switch provided on the operation unit 11, it is possible to observe the near view.

Next, when observing a distant view, the operator turns on a focus position variable switch provided on the operation unit 11. Thus, a voltage is supplied to the piezoelectric element 66 via the power supply line 67, and the piezoelectric element 66 is in an expanded state.

As described above, when the piezoelectric element 66 is in the expanded state, the glass plate 58 is pushed out through the prism 65 toward the distal end surface 19a of the distal rigid portion 19 by the tensile force of the piezoelectric element 66. Of the holding member 53 is in contact with one end 58a of the holding member 53. Then, in this state, the objective optical system is adjusted so as to focus on a distant view on the CCD image sensor 2.

For this reason, by turning on the variable focus position switch provided on the operation unit 11, it is possible to observe a distant view.

As described above, in the electronic endoscope according to the ninth embodiment, the voltage of the piezoelectric element 66 is controlled on / off so that the CCD image sensor 2 is moved in the direction of the distal end face 19a of the distal end rigid portion 19 and in the rearward direction. By sliding in the direction of the end face 19b, the optical path length (focusing position) of the imaging light can be changed stepwise. This makes it possible to observe both the near view and the distant view despite the fact that the objective optical system has a fixed focus. For example, it is substantially the same as the electronic endoscope scope according to the above-described first embodiment. The effect can be obtained.

Next, an electronic endoscope according to a tenth embodiment of the present invention will be described.

The electronic endoscope according to the ninth embodiment described above converts the imaging light refracted by the prism 65 into a CCD.
Although the light was received by the image sensor 2, the first
The electronic endoscope scope according to the zeroth embodiment is such that the imaging light taken in via the objective lens 1 is directly received by the CCD image sensor 2.

In the electronic endoscope according to the tenth embodiment, the same reference numerals are given to the portions showing the same operations as those in the electronic endoscope according to the ninth embodiment. A detailed description thereof will be omitted.

FIG. 11 is a sectional view of an objective optical system provided in a rigid distal end portion 19 of the electronic endoscope according to the tenth embodiment.

In FIG. 10, the tip rigid portion 19 is provided with a CCD in a substantially hollow cylindrical tip rigid portion main body 51 at a position where the imaging light from the objective lens 1 is directly and accurately received.
An image sensor 2 is provided.

The CCD image sensor 2 is fixed to a glass plate 53 on which a wiring pattern is deposited. Also, C
The back surface (the surface opposite to the light receiving surface of the imaging light) of the CD image sensor 2 is fixed to the rear end surface 19 b of the front end rigid portion 19 via the piezoelectric element 66.

As described above, the piezoelectric element 66 expands and contracts by voltage on / off control. When the piezoelectric element 66 is in a contracted state, the contraction force of the piezoelectric element 66 causes the CCD image sensor 2 to expand and contract. The glass plate 58 is pulled in the direction of the rear end face 19b of the distal end hard portion 19 via the other end, and the other end 58b of the glass plate 58 is
To come into contact with. In this state, the optical system is adjusted to a fixed focus type objective optical system that focuses the near view on the CCD image sensor 2.

When the piezoelectric element 66 is in the extended state, the glass plate 58 is moved by the extension force of the piezoelectric element 66 via the CCD image sensor 2 to the distal end surface 1 of the rigid distal end portion 19.
It is extruded in the direction 9a so that one end 58a of the glass plate 58 comes into contact with the contact portion 53a of the holding member 53. In this state, the optical system is adjusted to a fixed focus type objective optical system that focuses a distant view on the CCD image sensor 2.

Next, the operation of the electronic endoscope having the above-described configuration according to the tenth embodiment will be described.

First, when observing the near view, the operator turns off the focus position variable switch provided on the operation unit 11. As a result, no voltage is supplied to the piezoelectric element 66 via the power supply line 67, and the piezoelectric element 66 maintains a contracted state.

As described above, when the piezoelectric element 66 is in the contracted state, the glass plate 58 is pulled in the direction of the rear end face 19b through the CCD image sensor 2 by the contracting force of the piezoelectric element 66, The other end 58 of the glass plate 58
b comes into contact with the contact portion 53a of the holding member 53. Then, in this state, the objective optical system is adjusted so as to focus on a near view on the CCD image sensor 2.

For this reason, by turning off the focus position variable switch provided on the operation unit 11, it is possible to observe the foreground.

Next, when observing a distant view, the surgeon turns on the focus position variable switch provided on the operation unit 11. Thus, a voltage is supplied to the piezoelectric element 66 via the power supply line 67, and the piezoelectric element 66 is in an expanded state.

As described above, when the piezoelectric element 66 is in the expanded state, the glass plate 58 is pushed out through the CCD image sensor 2 in the direction of the distal end surface 19a of the rigid distal end portion 19 due to the tensile force of the piezoelectric element 66. One end 58 of plate 58
a comes into contact with the contact portion 53 a of the holding member 53. Then, in this state, the objective optical system is adjusted so as to focus on a distant view on the CCD image sensor 2.

For this reason, by turning on the focus position variable switch provided on the operation section 11, it is possible to observe a distant view.

As described above, in the electronic endoscope scope of the tenth embodiment, the CCD image sensor 2 is controlled to turn on and off the voltage of the piezoelectric element 66 so as to move the CCD image sensor 2 in the direction of the distal end surface 19a of the distal end rigid portion 19 and in the rearward direction. By sliding in the direction of the end face 19b, the optical path length (focusing position) of the imaging light can be changed stepwise. Accordingly, substantially the same effects as those of the electronic endoscope according to the above-described first embodiment can be obtained, such as enabling observation of both the near view and the distant view.

Next, an electronic endoscope according to an eleventh embodiment of the present invention will be described.

The electronic endoscope according to the eleventh embodiment enables distant view observation and near view observation by changing the optical path length using an electrostatic actuator.

FIG. 12 is a sectional view of an objective optical system provided in the rigid distal end portion 19 of the electronic endoscope according to the eleventh embodiment.

In FIG. 12, an electrostatic actuator as an objective optical system includes a prism 70 for reflecting an optical image captured by the objective lens 1, a plate-shaped movable element 71 on which the prism 70 is mounted, and The prism 70 is provided so as to face the prism 70 with the mover 71 interposed therebetween.
And a CCD image sensor 2 for receiving an optical image reflected by the optical element and incident via the mover 71.

This electrostatic actuator has a substantially U-shaped cross section and a first stator 72 supporting one end of a movable element 71 by a gap, and has a substantially inverted U-shaped cross section. The second stator 73 supporting the other end of the mover 71 by the portion
A power supply circuit 74 for applying a voltage to the mover 71 and each of the stators 72 and 73; and a controller 75 for controlling the power supply circuit 74 in accordance with the operation of the focus position variable switch provided on the operation unit 11. Have.

The mover 71 and each of the stators 72 and 73 are formed using an insulating member such as ceramic or plastic, and a metal thin film is formed on the surface thereof by using a thin film forming technique such as a so-called sputtering method. Is formed.

The gap between the stators 72 and 73 is filled with air. The gap may be filled with a non-dielectric substance such as pure water (preferably a liquid or a fluid that does not hinder the movement of the mover 71).

Also, the prism 70 and the CC of the mover 71
The portion sandwiched by the D image sensor 2 is where the optical image from the prism 70 is effectively used.
For example, a transparent portion is formed so that a metal thin film is not deposited on this portion.

In this electrostatic actuator, the mover 71 is moved between the stators 72 and 73 by electrostatic drive. One end of the mover 71 is connected to the first stator. When it comes into contact with the inner wall of the gap 72, an optical image of the near view is formed on the CCD image sensor 2. On the contrary, the other end of the mover 71 is connected to the second stator 73. When it comes into contact with the back wall of the gap portion, the optical image of the distant view has a fixed focus formed on the CCD image sensor 2.

Since the electronic endoscope is used for observing narrow places such as body cavities, etc.
The area occupied by this electrostatic actuator within 9 is restricted. In particular, in the thickness direction (tip hard portion 1
9 in the radial direction).

On the other hand, the strength required of the mover 71 is a strength capable of supporting the prism 70 and the CCD image sensor 2, and the strength required of each of the stators 72 and 73 is capable of supporting the mover 71. Strength. Further, the driving force of this electrostatic actuator is determined by the area of a portion (electrode portion) at which one end and the other end of the mover 71 are opposed to the stators 72 and 73, so that the mover 71 and the stators 7
The thickness of 2, 73 does not affect the driving force of the electrostatic actuator. Furthermore, the mover 71 and each stator 72,
The thickness of the metal thin film formed on the surface of 73 is, for example, about several thousand angstroms. For this reason, the mover 71 and each of the stators 72 and 73 can be formed very thin.

Therefore, this electrostatic actuator can be formed extremely small, and the dead space in the rigid tip portion 19 (the area occupied by the electrostatic actuator in the rigid tip portion 19) is small. It can be easily stored in the distal end rigid portion 19. Therefore, it is possible to sufficiently cope with the above-mentioned restrictions.

Note that an electromagnetic actuator can be used instead of the electrostatic actuator. However, the electromagnetic actuator needs to be provided with a coil or a magnet. Considering the provision, it can be said that the electrostatic actuator is more preferable.

Next, the eleventh embodiment having such a configuration will be described.
The operation of the electronic endoscope according to the embodiment will be described.

FIG. 13 shows the second stator 73 side of the electrostatic actuator, and is a diagram showing the driving principle of the electrostatic actuator.

First, when observing a distant view using the electronic endoscope, the surgeon operates the focusing position variable switch provided on the operation unit 11 to designate observation of the distant view.

When the observation of the distant view is designated, the controller 75 controls the power supply circuit 74 so as to apply a voltage between the mover 71 and the second stator 73.

When a voltage is applied between the mover 71 and the second stator 73, the suction force (F
x) operates, the mover 71 is drawn into the gap of the second stator 73, and the mover 71 moves to the second stator 73 side.

Fx = 2 (εLV ² ) / 2d (Equation 3) (ε = ε ₀ · ε _r , ε ₀ : dielectric constant of vacuum, ε _r : dielectric constant of substance, L is stator And V is an applied voltage value. Then, the other end of the mover 71 abuts on the inner wall of the gap of the second stator 73 due to the suction force (Fx). As described above, when the other end of the mover 71 comes into contact with the inner wall of the gap portion of the second stator 73, the optical image of the distant view is adjusted so as to be formed on the CCD image sensor 2. I have. Therefore, it is possible to observe a distant view.

Next, when observing the foreground using this electronic endoscope, the surgeon operates the focus position variable switch provided on the operation unit 11 to designate observation of the foreground.

When the observation of the near view is designated, the controller 75 controls the power supply circuit 74 so as to apply a voltage between the mover 71 and the first stator 72.

When a voltage is applied between the mover 71 and the first stator 72, a suction force similar to the suction force (Fx) shown in the above equation (3) acts to move the mover 71 to the first fixed member. The movable element 71 is moved to the second stator 73 side by being drawn into the gap of the element 72.

Then, one end of the mover 71 abuts on the inner wall of the gap of the first stator 72 due to the suction force. As described above, when one end of the mover 71 comes into contact with the inner wall of the gap of the first stator 72, the optical image of
It is adjusted so that an image is formed on the image sensor 2. For this reason, it is possible to observe the near view.

As described above, the electronic endoscope according to the eleventh embodiment operates the focus position variable switch to move the movable member 71 of the electrostatic actuator and the first stator 7.
2 and the voltage applied between the mover 71 and the second stator 73 is switched to move the mover 71 toward the first stator 72 or the second stator 73. Thus, the optical path length can be variably controlled. For this reason, the same effect as the electronic endoscope according to the above-described first embodiment can be obtained, for example, the focus position can be changed, and a distant view and a near view can be observed. .

In the electronic endoscope according to the eleventh embodiment, the focusing position can be finely adjusted by changing the optical path length using an electrostatic actuator. Furthermore, since the focus position is finely adjusted only by the focus position variable switch provided on the operation unit 11, the operability of the electronic endoscope can be improved.

Next, an electronic endoscope according to a twelfth embodiment of the present invention will be described.

The electronic endoscope according to the twelfth embodiment uses an electrostatic actuator similarly to the electronic endoscope according to the eleventh embodiment. The configuration of the stator and the form of voltage application to each stator are different.

The electronic endoscope according to the twelfth embodiment differs from the electronic endoscope according to the eleventh embodiment only in this point. In the description of such an electronic endoscope scope, the same reference numerals are given to portions showing the same operations as those of the electronic endoscope scope according to the eleventh embodiment, and redundant description will be omitted.

First, FIG. 14 is a sectional view of the second stator 80 of the objective optical system provided in the distal end rigid portion 19 of the electronic endoscope according to the twelfth embodiment. is there.

In FIG. 14, the second stator 80
Has a substantially inverted U-shaped cross section, but the first stator piece 81 and the first stator piece 81 are formed by a straight line extending in the horizontal direction (moving direction of the mover 71) from the middle portion of the back wall. Second
Is divided into two pieces. The stator pieces 81 and 82 are provided at a certain distance so that there is no electrical contact, or are connected via a spacer such as an insulating member. That is, a metal thin film is deposited on each of the stator pieces 81 and 82, and when a voltage is applied between the first stator piece 81 and the mover 71, this voltage becomes the second voltage. The voltage is not applied to the stator piece 82, and conversely, if a voltage is applied between the second stator piece 82 and the mover 71, this voltage is not applied to the first stator piece 81. Each stator piece 81,
82 are insulated.

The application of a voltage to each of the stator pieces 81 and 82 is switched by a changeover switch 83. The first stator piece 81 is connected to a selected terminal 83a of the changeover switch 83 by a switch. The second stator piece 82 is connected to a selected terminal 83 b of the changeover switch 83.
, Respectively.

The power supply circuit 74 includes the changeover switch 8
The controller 75 supplies the power supply voltage supplied to the selection terminal 83c to the stator pieces 81, 82 via the selected terminals 83a, 83b. Select terminal 83 to supply
c is switched and controlled.

The electrostatic actuator is provided with a first stator having a similar configuration in addition to the second stator 80. That is, this first stator also
The power supply circuit 74 has a configuration in which the power supply voltage supplied from the power supply circuit 74 is supplied to each stator piece via a changeover switch.

Here, in the electrostatic actuator, the movable element is sandwiched from above and below by a substantially U-shaped or substantially inverted U-shaped stator, and the movable element is moved by the attraction force (Fx) shown in the above-mentioned equation (3). Is pulled to the stator side. At this time, together with the suction force (Fx: the suction force in the moving direction), the suction force in the direction orthogonal to the suction force (Fx) is expressed by the following equation 4. Vertical suction force (Fy) acts.

Fy = εwLV ² / 2d ² (Equation 4) (w: the area of the portion where the stator and the mover overlap) When the vertical suction force acts, the mover 71 and the first When a voltage is applied between the stator piece 81 and the movable piece 71
Are attracted to the first stator piece 81 and when a voltage is applied between the mover 71 and the second stator piece 82, the mover 71
May be adsorbed to the second stator piece 82, which may hinder smooth movement control of the mover 71.

For this reason, in the electrostatic actuator, the controller 75 controls the switching of the changeover switch 83 to control the timing of the voltage applied between the mover 71 and each of the stator pieces 81 and 82. , Mover 71
Is prevented from adhering to the stator pieces 81 and 82.

FIGS. 15A and 15B are views showing a state where the controller 75 controls the changeover switch 83 so that the mover 71 does not stick to the stator pieces 81 and 82. FIG.

When the operator operates the in-focus position variable switch and designates observation of a distant view, the controller 75 first moves the movable element 71 and the second movable element as shown in FIG.
The power supply circuit 74 is controlled so that a voltage is applied to the stator piece 82, and the changeover switch 83 is controlled so that the selection terminal 83c selects the selected terminal 83b. As a result, the above-described suction force (Fx) in the moving direction acts between the mover 71 and the second stator piece 82, so that the mover 71 is drawn into the gap of the second stator 80. Moving.

Next, the controller 75 operates as shown in FIG.
As shown in the figure, the power supply circuit 74 is controlled so that a voltage is applied between the mover 71 and the first stator piece 81, and the changeover switch 83 is selected so that the selected terminal 83a is selected by the selection terminal 83c. Is switched. Accordingly, a suction force (Fx) in the moving direction acts between the mover 71 and the first stator piece 81, and the mover 71 moves so as to be drawn into the gap of the second stator 80. .

Here, the above-described vertical attractive force (Fy) acts on the stator piece to which a voltage is applied. Therefore, the controller 75 performs an operation of selecting the selected terminal 83b with the selection terminal 83c shown in FIG. 15A and an operation of selecting the selected terminal 83a with the selection terminal 83c shown in FIG. The changeover switch 83 is controlled so as to be repeated at a high speed.

Thus, before the mover 71 is attracted to the first stator piece 81 or the second stator piece 82 by the vertical attraction force (Fy) (or immediately after the mover 71 is attracted), the work is performed until that time. The upward suction force that was
Alternatively, since the downward suction force can be changed to the upward suction force, the movement of the mover 71 can be controlled only by the pseudo suction force (Fx) in the movement direction. For this reason, the inconvenience that the mover 71 is attracted to the second stator 80 can be prevented, and the movement of the mover 71 can be smoothly controlled. Then, by controlling the movement of the mover 71 in this way, the other end of the mover 71 abuts on the inner wall of the gap portion of the second stator 80, so that a distant view can be observed.

When observing the near view, similarly to the case of observing the distant view, the controller 75 controls the changeover switch provided on the first stator side at a high speed. As a result, a voltage is alternately applied to the first stator piece and the second stator piece of the first stator, and the movement of the mover 71 is controlled only by the attraction force (Fx) in the movement direction. be able to. Then, one end of the mover 71 abuts on the back wall of the gap of the first stator, so that a close-up view can be observed.

Lastly, in the description of each of the above embodiments,
Although the endoscope device according to the present invention is applied to an electronic endoscope scope used in the medical field, this endoscope device can be used for observing narrow places and details in fields such as the industrial industry. The present invention can also be applied to an endoscope device used. In this case, it is possible to perform a product inspection or the like in a narrow place or in detail, which can greatly contribute to the production industry and the like.

In the description of the eleventh and twelfth embodiments, the optical path of the optical image is refracted by the prism 70 and received by the CCD image sensor 2. As in the case of the electronic endoscope according to the eighth and tenth embodiments described with reference to FIG.
Optical image without refracting the optical path of the optical image
The light may be directly received by the image sensor 2.

When the focusing position of the objective lens 1 is 1 mm
Thus, the refractive index of the variable refractive index element 3 when the voltage is supplied is 1.51.
Although the description has been given with specific numerical values such as a refractive index of 1.71 or the like when no voltage is supplied, this is merely an example, and other than that, as long as the technical idea according to the present invention is not deviated. It goes without saying that various changes can be made according to the design and the like.

[0196]

The endoscope apparatus according to the present invention has a simple structure without increasing the outer diameter of the rigid portion at the distal end and without increasing the length of the rigid portion at the distal end. It is possible to observe a near view and a distant view while using an optical system.

[Brief description of the drawings]

FIG. 1 is a diagram showing an objective optical system of an electronic endoscope scope according to a first embodiment to which an endoscope apparatus according to the present invention is applied.

FIG. 2 is a diagram showing an overall configuration of the electronic endoscope.

FIG. 3 is a view showing a state in which a distal end rigid portion of the electronic endoscope is bent.

FIG. 4 is a view for explaining a configuration of a distal end surface of the distal end rigid portion.

FIG. 5 is a diagram for explaining an overall resolution characteristic of the electronic endoscope.

FIG. 6 is a diagram showing a specific example of a focus position of the electronic endoscope.

FIG. 7 is a diagram showing a configuration of a liquid crystal lens provided in a rigid distal end portion of an electronic endoscope according to a second embodiment of the present invention.

FIG. 8 is a diagram showing an objective optical system of an electronic endoscope according to a seventh embodiment of the present invention.

FIG. 9 is a diagram showing an objective optical system of an electronic endoscope according to an eighth embodiment of the present invention.

FIG. 10 is a diagram showing an objective optical system of an electronic endoscope according to a ninth embodiment of the present invention.

FIG. 11 is a diagram showing an objective optical system of an electronic endoscope according to a tenth embodiment of the present invention.

FIG. 12 is a diagram showing an objective optical system of an electronic endoscope according to an eleventh embodiment of the present invention.

FIG. 13 is a diagram for explaining the operation of the objective optical system of the electronic endoscope according to the eleventh embodiment.

FIG. 14 is a diagram showing an objective optical system of an electronic endoscope according to a twelfth embodiment of the present invention.

FIG. 15 is a diagram for explaining the operation of the objective optical system of the electronic endoscope according to the twelfth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Objective lens, 2 ... CCD image sensor, 3 ... Variable refractive index element 3a ... Glass substrate, 3b ... Nematic liquid crystal member, 4 ...
Power supply, 11 Operating unit 12 Connector terminal, 14 Angle pick, 15 Operation key group 16 Focus adjustment key, 19 End rigid part, 19a End surface of rigid end part 31 Plano-concave lens, 32, 42 ... Glass substrate, 41: Plano-convex lens 33, 43: Nematic liquid crystal member, 51: Tip rigid body 57: Prism, 58: Glass plate, 60: Wire cable, 61: Adhesive member 62: Wire guide, 71: Electrostatic actuator Movable element 72: first stator of electrostatic actuator, 74: power supply circuit 73: second stator of electrostatic actuator, 75: controller 83: changeover switch

Claims (13)

[Claims] 1. An objective lens for forming an optical image of a subject, capturing means for capturing an optical image formed by the objective lens, and an optical path for varying an optical path length of the optical image from the objective lens. An endoscope apparatus comprising: a variable length unit. 2. The endoscope apparatus according to claim 1, wherein said capturing means is a solid-state image sensor. 3. The endoscope apparatus according to claim 1, wherein the optical path length changing unit changes the optical path length of the optical image in a stepwise manner. 4. An apparatus according to claim 1, wherein said optical path length varying means is a refractive index varying means capable of varying a refractive index, and changes an in-focus position of a subject of said objective lens. An endoscope apparatus according to any one of the preceding claims. 5. The endoscope apparatus according to claim 4, wherein said refractive index changing means is capable of changing a refractive index according to an external force. 6. The endoscope apparatus according to claim 4, wherein said refractive index variable means is a liquid crystal member or an ion enclosing member enclosing an ionic liquid. 7. The optical path length changing means changes the focus position of the object of the objective lens by sliding the capturing means or the solid-state imaging device in an optical axis direction of an optical image from the objective lens. The endoscope apparatus according to any one of claims 1 to 3, wherein: 8. An optical path length varying means, comprising: an optical path refracting means for refracting an optical path of an optical image from the objective lens; an optical path refracting means; and an optical image refracted by the optical path refracting means. A slide plate on which the capturing unit or the solid-state imaging device is provided so as to be capable of being loaded; a slide mechanism capable of sliding the slide plate in an optical axis direction of an optical image from the objective lens; The endoscope apparatus according to claim 7, further comprising a wire cable that slides the slide plate in the optical axis direction by applying a force in the optical axis direction to the optical path refracting means. 9. The optical path length varying means includes: a slide plate provided with the capturing means or the solid-state imaging element for capturing an optical image from the objective lens; and an optical axis of the optical image from the objective lens. A sliding mechanism slidable in the direction, provided on the capturing means or the solid-state imaging device,
The endoscope apparatus according to claim 7, further comprising a wire cable that slides the slide plate in the optical axis direction by applying the force in the optical axis direction to the capturing unit or the solid-state imaging device. 10. The optical path length varying means includes: an optical path refracting means for refracting an optical path of an optical image from the objective lens; an optical path refracting means; and an optical image refracted by the optical path refracting means. A slide plate on which the capturing means or the solid-state imaging device is provided so as to be capable of being loaded; a slide mechanism capable of sliding the slide plate in an optical axis direction of an optical image from the objective lens; 8. A piezoelectric element, which is provided, expands and contracts in the optical axis direction by controlling on / off of a voltage, and slides the slide plate in the optical axis direction via the optical path refracting means. Endoscope device. 11. The optical path length varying unit includes: a slide plate provided with the capturing unit or the solid-state imaging device that captures an optical image from the objective lens; and a slide plate provided with the optical image light from the objective lens. A sliding mechanism slidable in the axial direction, provided on the capturing means or the solid-state imaging device,
By controlling the voltage on and off, it expands and contracts in the optical axis direction,
The endoscope apparatus according to claim 7, further comprising: a piezoelectric element that slides the slide plate in the optical axis direction via the capturing unit or the solid-state imaging device. 12. The optical path length varying means includes: a conductive movable element provided with the capturing means for capturing an optical image from the objective lens or the solid-state imaging element; and a movable element arranged in the optical axis direction of the optical image. A conductive first stator that holds one end of the mover so as to be movable, and holds the other end of the mover so that the mover can be moved in the optical axis direction of the optical image. By applying a voltage between the conductive second stator and the mover and the first stator, or between the mover and the second stator, the mover and the first Control for generating electrostatic attraction between the stator or between the mover and the second stator to control the movement of the mover to the first or second stator side along the optical axis direction. The endoscope apparatus according to claim 7, comprising means. 13. The first stator and the second stator are divided into a first stator piece and a second stator piece along the optical axis direction. 13. The method according to claim 12, wherein a voltage applied to each stator piece is switched at a predetermined timing so as to generate an electrostatic attraction force alternately between the mover and each stator piece. Endoscope device.