JP2019076329A - Front-end lens device and ophthalmologic microscope - Google Patents

Abstract

An object of the present invention is to make it possible to use a plurality of front lenses with different focal lengths, without touching the hands of a surgeon and an assistant working near the eye to be examined, and an ophthalmic microscope. The purpose of this study is to develop a pre-lens device that does not fall within the observation field. A front lens holder for holding a liquid lens (6) in a front lens device (1) used in an ophthalmic microscope (2) having an observation optical system for observing an eye (11) to be examined. (4) and a focal length control mechanism that changes the focal length of the liquid lens (6) by deforming the shape of the liquid lens (6). )I will provide a. [Selection] Figure 1

Description

The present invention relates to an ophthalmic microscope for observing a subject's eye under magnification, and a front lens apparatus for inserting a front lens between an objective lens of the ophthalmic microscope and the subject's eye.
The invention relates in particular to a pre-lens arrangement with a liquid lens and an ophthalmic microscope with such a pre-lens arrangement.

An ophthalmologic microscope is a medical or examination instrument capable of magnifying and observing a subject's eye to be examined by an observation optical system including a lens or the like.
Some ophthalmologic microscopes have a function of observing an anterior segment (for example, cornea, anterior capsule, sclera etc.) and a function for observing a posterior segment (for example, retina). In this type of ophthalmic microscope, it is possible to switch between anterior segment observation and posterior segment observation by inserting or removing the front lens into the optical path of the observation optical system between the objective lens and the eye to be examined.

When observing the anterior segment, as shown in FIG. 12A, the anterior segment of the eye 11 is positioned at the focal position (front focal position) U0 that is closer to the subject eye 11 than the objective lens 13 of the observation optical system. Thus, the distance H2 between the objective lens 13 and the eye 11 to be examined is set. Assuming that the focal distance from the objective lens 13 of the observation optical system is F1, H2 = F1.
On the other hand, at the time of the posterior eye observation, as shown in FIG. 12B, the distance H2 'between the objective lens 13 and the eye 11 to be examined is set longer, and between the front focal position U0 and the eye 11 to be examined. The front lens 6 is placed. The front lens 6 guides the light of the observation optical system as parallel light to the lens 11b of the eye to be examined, and is arranged to focus on the retina 11a through the lens 11b. Assuming that the focal length of the front lens 6 is F2, typically, H2 '≒ F1 + 2 × F2.

Various types of pre-lens devices have been developed as pre-lens devices that support the pre-lens in the optical path in a removable manner.
For example, a front lens is inserted below the objective lens by the lens supporting arm having the upper arm portion and the lower arm portion foldable in the direction along the upper arm portion and having one end held at the lower end portion of the upper arm portion Pre-lens devices that can be disengaged have been developed (US Pat.
In addition, a head of a revolver system in which two head lenses are attached via a lens holder bent to a lens receiving portion that rotates about a rotation axis tilted with respect to the optical axis of the observation optical system of the ophthalmic microscope Lens devices have been developed. This front lens device can switch two front lenses on the light path of the observation optical system (Patent Document 2 [0120]).

  Thus, in the conventional pre-lens apparatus, the number of pre-lenses held is usually one or two, and in order to use pre-lenses with different focal lengths, the pre-lenses are manually replaced It was necessary.

Unexamined-Japanese-Patent No. 2004-229929 JP, 2009-205156, A

When using an ophthalmic microscope for surgery, it is common to use at least three types of front lenses having different focal lengths. Conventionally, three types of front lenses need to be replaced manually, which is troublesome to operate, and each time the concentration of the surgeon is interrupted, the efficiency is deteriorated.
In addition, although a pre-lens apparatus has been developed in which a plurality of pre-lenses can be interchanged by a mechanical mechanism, since the pre-lens apparatus occupies a large space near the subject's eye, it is near the subject's eye There is a problem that there is a risk of touching the hands of a surgeon and an assistant working at the same time, and there is a risk of entering into the observation field of the ophthalmologic microscope.

  Therefore, in view of the above-mentioned conventional situation, the present invention makes it possible to use a plurality of front lenses having different focal lengths, without touching hands of a surgeon and an assistant working near the eye to be examined. Also, it is an object of the present invention to develop a front lens device which does not fall within the viewing field of an ophthalmic microscope.

  In order to solve the above-mentioned problems, the inventors of the present application conducted earnest research and as a result, by using a liquid lens as a front lens, multiple types having different focal lengths with one liquid lens can be used without using a plurality of lenses. It has been found that the space required for the front lens device can be reduced because the front lens can be realized, and the present invention has been completed.

That is, the present invention provides the following first invention regarding the pre-lens apparatus and the following second invention regarding the ophthalmic microscope.
(1) A first aspect of the present invention relates to a front end lens apparatus for use in an ophthalmic microscope having an observation optical system for observing an eye to be examined.
A front lens holder for holding a liquid lens;
The present invention relates to a front lens apparatus having a focal length control mechanism that changes a focal length of the liquid lens by changing a shape of the liquid lens.
(2) In the front lens apparatus of the first invention, the focal length control mechanism includes an electrode provided around the liquid lens, a voltage amplifier for applying a voltage to the electrode through a lead, and the voltage amplifier It is preferable to have a controller that controls the voltage of
(3) In any of the above-described front lens devices, the front lens holder has a container that transmits light,
By sealing a polar liquid and a nonpolar liquid in the container, an interface can be formed between the polar liquid and the nonpolar liquid, and a liquid lens having the interface as a refractive surface can be formed.
(4) In the front lens device of (2) or (3),
An electrode and an insulating film are provided in this order on the inner surface of two opposing transparent substrates, and a container transmitting light is formed by the transparent substrates and a spacer member provided therebetween.
A polar liquid and a nonpolar liquid are enclosed in the container to form an interface between the polar liquid and the nonpolar liquid, and a liquid lens having the interface as a refractive surface is formed.
By applying a voltage to the electrode, the interface can be changed to change the focal length of the liquid lens.
(5) In any one of the front lens devices, the liquid lens is preferably a liquid lens capable of changing the focal length to infinity.
(6) A second invention relates to an ophthalmic microscope having an observation optical system for observing an eye to be examined, the ophthalmic microscope having the front lens described in any of the above.
(7) In the ophthalmic microscope of the second invention, it is insertable into and removable from the optical axis of the observation optical system, and is used to adjust the focal position closer to the eye to be examined than the objective lens of the observation optical system. It is preferable to have an objective auxiliary lens.
(8) In the ophthalmic microscope of (7), the objective auxiliary lens is preferably a lens having a negative power.
(9) In the ophthalmic microscope of (7) or (8), it is preferable to have a switching mechanism for inserting, removing or replacing the objective auxiliary lens in conjunction with the change of the focal length of the liquid lens.
(10) In the ophthalmic microscope of any one of the above (7) to (9), in the case of changing the focal length of the liquid lens to at least n types, it is preferable to have at least n objective auxiliary lenses.

  The pre-lens apparatus and the ophthalmic microscope of the present invention use a liquid lens capable of changing the focal length by the focal length control mechanism as the pre-lens, so that one liquid lens is used without using a plurality of lenses. Thus, it is possible to realize multiple types of front lenses having different focal lengths. For this reason, space saving of the front lens device can be achieved while enabling use of a plurality of types of front lenses, so that the front lens device works with the surgeon and assistant working near the eye to be examined. It is possible to suppress the risk of contact with the hand and the risk of entering the observation field of view of the ophthalmic microscope.

It is a schematic diagram which shows the front lens apparatus and the ophthalmic microscope of the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the front lens holder used in the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the front lens holder used in the 2nd Embodiment of this invention. It is a schematic diagram which shows the relationship of the distance of an objective lens and a to-be-tested eye when inserting and removing a front lens holder and switching an anterior ocular segment observation and a posterior ocular segment observation. It is a schematic diagram which shows the relationship of the distance of an objective lens and a to-be-tested eye in, when the focal distance of a liquid lens changes. The ophthalmic microscope of the 3rd Embodiment of this invention WHEREIN: It is a side view which shows typically the structure of the optical system at the time of observing an anterior segment. The ophthalmic microscope of the 3rd Embodiment of this invention WHEREIN: It is a front view which shows typically the structure of the optical system at the time of observing an anterior segment. It is drawing which shows typically arrangement | positioning of the objective auxiliary lens at the time of observing an anterior segment. FIG. 8 (A) shows the arrangement of the objective auxiliary lens in the ophthalmic microscope of the third embodiment of the present invention, and FIG. 8 (B) shows the objective auxiliary lens on the opposite side of the objective eye to the eye It shows the arrangement when it is provided. The ophthalmic microscope of the 3rd Embodiment of this invention WHEREIN: It is a side view which shows typically the structure of the optical system at the time of observing a back eye part. The ophthalmic microscope of the 3rd Embodiment of this invention WHEREIN: It is a front view which shows typically the structure of the optical system at the time of observing a back eye part. It is drawing which shows typically arrangement | positioning of the objective auxiliary lens at the time of observing a back eye part. FIG. 11 (A) shows the arrangement of the objective auxiliary lens in the ophthalmic microscope of the third embodiment of the present invention, and FIG. 11 (B) shows the objective auxiliary lens on the opposite side to the eye side of the objective lens. It shows the arrangement when it is provided. It is a schematic diagram which shows the relationship of the distance of an objective lens and a to-be-tested eye when inserting and removing a front lens and switching an anterior ocular segment observation and a posterior ocular segment observation.

1. Pre-lens device 1-1. Overview of Pre-Lens Device of the Present Invention The pre-lens device of the present invention relates to a pre-lens device used in an ophthalmic microscope having an observation optical system for observing an eye to be examined.
A front lens holder for holding a liquid lens;
And a focal length control mechanism for changing the focal length of the liquid lens by deforming the shape of the liquid lens.

The front lens device of the present invention uses a liquid lens held by a front lens holder as a front lens. The liquid lens can change its focal length by being deformed by the focal length control mechanism.
For this reason, it is possible to realize a plurality of types of front lenses having different focal lengths with one liquid lens, without using a plurality of front lenses as in the prior art. As a result, the space saving of the front lens device can be achieved while enabling the use of a plurality of types of front lenses, so that the front lens device operates in the vicinity of the eye to be examined It is possible to suppress the risk of contact with the hand and the risk of entering the observation field of view of the ophthalmic microscope.

The “liquid lens” in the present invention refers to an optical element capable of diverging or focusing light using refraction of light at the interface of the liquid.
The liquid lens is not limited to these, but, for example, a liquid lens that forms an interface when two types of liquids do not mix and forms an interface when a liquid and a gas make contact with each other. A liquid lens or a liquid lens that forms an interface with the outside of the container by containing the liquid in a deformable container can be used.

  When using a liquid lens that forms an interface by contacting two types of liquids without mixing, as a liquid lens, for example, a front lens holder having a container that transmits light is used to By sealing the polar liquid (hydrophilic liquid) and the nonpolar liquid (hydrophobic liquid), an interface is formed between the polar liquid and the nonpolar liquid which are not mixed with each other, and light refraction at the interface is utilized. Therefore, it can be used as a liquid lens.

Unlike a solid lens such as glass, a liquid lens can be easily deformed, so its focal length can be changed.
As a method of deforming the liquid lens, for example, a method of deforming the liquid lens by the technique of electrowetting that electrically changes the wettability of the liquid, or a method of deforming the liquid lens by increasing or decreasing the amount of liquid There is a method of deforming the liquid lens by applying pressure or tension.
Among them, research and development of a method to control the focal length by applying a voltage to the liquid lens to deform the liquid lens using the technique of electrowetting to electrically change the wettability of the liquid is advanced. There is.

In the pre-lens apparatus of the present invention, in the case of using a focal length control mechanism for changing the focal length of the liquid lens by applying a voltage, for example, an electrode provided around the liquid lens and a lead to the electrode It is preferable to have a focal length control mechanism that has a voltage amplifier that applies a voltage through and a controller that controls the voltage of the voltage amplifier.
Here, since the voltage amplifier is connected to the electrode by a conducting wire, it can be installed at a location away from the liquid lens. Therefore, with the focal length control mechanism as described above, it is necessary to install a large device around the liquid lens like a mechanical method in which the liquid lens is deformed by increasing or decreasing the amount of liquid or applying pressure. Instead, a large working space can be secured around the subject's eye.
Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

First Embodiment
FIG. 1 is a view schematically showing a front lens apparatus and an ophthalmic microscope according to a first embodiment of the present invention.
As shown in FIG. 1, the front lens device 1 has a front lens holder 4. In the front lens holder 4, the liquid lens 6 is held, and a focal length control mechanism (not shown) is provided.
The front lens holder 4 is inserted in the light path of the observation optical system. In FIG. 1, an optical axis O-300 of the observation optical system passing through the center of the optical path of the observation optical system is indicated by a dotted line. The optical path of the observation optical system passes through the liquid lens 6 held by the front lens holder 4 and enters the eye 11 to be examined.

As shown in FIG. 1, the front lens holder 4 is held by a first support arm 1001. The first support arm 1001 is connected to the second support arm, and the second support arm 1002 is connected to the support bracket 1004 so as to be rotatable about a pivot 1003. Therefore, by manually operating the pivot lever 1005, the first support arm 1001 and the second support arm 1002 can be pivoted. By this turning operation, the front lens holder 4 can be separated from the light path of the observation optical system. Also, the detached front lens holder 4 can be reinserted into the light path of the observation optical system by the operation of the turning lever 1005.
When the front lens holder 4 is inserted into the optical path of the observation optical system, the posterior eye portion (for example, the retina) of the eye 11 to be examined can be observed, and the front lens holder 4 is viewed from the optical path of the observation optical system In the case of detachment, the anterior segment (for example, cornea, anterior capsule, sclera, etc.) of the subject eye 11 can be observed.

The front lens holder 4 holds the liquid lens 6 inside, and the focal length of the liquid lens 6 can be changed by a focal length control mechanism. Therefore, with one liquid lens 6, it is possible to realize a plurality of types of front lenses having different focal lengths. Therefore, it is not necessary to arrange a plurality of front lenses around the subject's eye as in the case of a front lens apparatus that replaces a conventional front lens, and space saving of the front lens apparatus can be achieved.
As an example of use of the pre-lens apparatus of the present invention, for example, the operating doctor may set the focal length of the liquid lens 6 held by the pre-lens holder 4 inserted in the light path of the observation optical system to 2.5 cm. The inside of the subject's eye 11 is observed with the ophthalmic microscope 2. At this time, if the image is out of focus and the image in the eye 11 is largely blurred, the surgeon operates the focal length control mechanism of the front lens holder 4 using a foot switch (not shown) to The focal length of the lens 6 can be varied from 2.5 cm to 1.25 cm. Thus, the surgeon can change the focal length of the front lens without changing the front lens with the help of an assistant or the like as in the conventional case, and the operation efficiency of the operation can be improved.

  As shown in FIG. 1, the support bracket 1004 is connected to the front lens positioning device 1007 via a connection arm 1006. The front lens position adjusting device 1007 controls the upper and lower positions of the front lens holder 4 by driving the connecting arm 1006 up and down in the optical axis direction of the observation optical system. Thus, the distance between the objective lens of the ophthalmic microscope main body 12 and the liquid lens 6 can be adjusted according to the focal length of the liquid lens 6 held by the front lens holder 4.

As shown in FIG. 1, the front lens apparatus 1 includes a front lens holder 4, a first support arm 1001, a second support arm 1002, a pivot 1003, a support bracket 1004, a pivot lever 1005, a connecting arm 1006, and It comprises a front lens position adjusting device 1007.
The front lens device 1 is attached to the ophthalmic microscope main body 12. The front lens unit 1 can also be attached via an attachment unit (not shown) so as to be easily detachable from the ophthalmic microscope main body 12. In addition, the front lens device 1 may be non-removably attached to the ophthalmic microscope main body 12.
The ophthalmic microscope 2 is configured to include an ophthalmic microscope main body 12 and a front lens device 1.
The ophthalmic microscope main body 12 has a lens barrel 14 that accommodates an optical element such as a lens of an observation optical system, and the objective lens 13 is installed on the most eyelid 11 side of the lens barrel 14.

  When the front lens is inserted into the optical path of the observation optical system, the image of the eye to be examined is inverted to be a reverse image, and a lens unit for returning this to a normal image is provided in the inverter unit 15. For the optical system of the lens unit provided in the inverter unit 15, for example, the one disclosed in Japanese Patent Publication No. 7-48091 can be used. The lens unit can be inserted into and removed from the optical path in the lens barrel by manually operating the switching lever 16 in conjunction with the insertion and removal of the front lens holder 4 by the operation of the pivot lever 1005. In addition, the lens unit can be automatically inserted and removed from the optical path in the lens barrel by operating an actuator (not shown) in conjunction with the insertion and removal of the front lens holder 4 by the pivot lever 1005.

FIG. 2 is a schematic view showing the structure of a front lens holder used in the first embodiment of the present invention.
In FIG. 2, reference numerals 411 and 412 denote circular transparent glass substrates, and transparent electrodes 501 and 502 are formed on the inner surfaces of the two glass substrates 411 and 412 by patterning. The transparent electrode can be formed, for example, by vapor deposition of indium tin oxide (ITO).
Insulating films 421 and 422 are formed on the inner surface of the transparent electrodes 501 and 502, and water repellent and oil repellent films 431 and 432 are formed on the surfaces of the insulating films 421 and 422.

  The insulating films 421 and 422 are preferably transparent, and can be formed, for example, by applying a solution of polyvinylidene fluoride in which nanoparticles of an inorganic term dielectric are dispersed. As a material of the water and oil repellent films 431 and 432, for example, polyparaxylylene, polytetrafluoroethylene, a fluorine-based polymer, a silicone resin or the like is used.

As shown in FIG. 2, a glass ring member 44 as a spacer member is provided between the glass substrates 411 and 412, whereby the glass substrates 411 and 412 are arranged opposite to each other at a constant distance. It is set up.
The durable adhesive 45 is applied to the outer peripheral surface of the glass ring member 44, whereby the glass ring member 44 is joined to the water / oil repellent films 431, 432 on the surfaces of the glass substrates 411, 412.
A container for transmitting light is formed by the glass substrates 411 and 412 provided with the transparent electrodes 501 and 502, the insulating films 421 and 422, and the water and oil repellent films 431 and 432 on the surface, and the glass ring member 44. . Then, after the polar liquid 601 and the nonpolar liquid 602 are sealed in the container, the inlet of the container is sealed by the sealing member 46 made of a UV curing resin.

As the polar liquid 601, for example, one containing water as a main component and to which an antifreeze liquid is added is used. Examples of the nonpolar liquid 602 include hydrocarbon materials such as hexane, octane, decane, dodecane, hexadecane, undecane, benzene, toluene, xylene, mesitylene, butylbenzene, 1,1-diphenylethylene, and transparent silicones. Oil or the like is used.
Since the polar liquid 601 and the nonpolar liquid 602 do not mix with each other, the interface 6a is formed at the boundary. Since light is refracted at this interface 6 a, a liquid lens can be formed in the front lens holder 4.

As shown in FIG. 2, the transparent electrodes 501 and 502 are connected to the voltage amplifier 7 via the conductors 901 and 902. The magnitude of the voltage applied to the transparent electrodes 501 and 502 by the voltage amplifier 7 can be controlled by the controller 8. As described above, by controlling the voltage applied to the transparent electrodes 501 and 502 by the control device 8, it is possible to control the change of the focal length of the liquid lens.
For example, by changing the voltage applied between the transparent electrodes 501 and 502, the contact angle of the nonpolar liquid 602 is changed to change the shape of the interface 6a from that shown by a solid line as shown in FIG. , Can be changed to those shown by dotted lines. Thereby, the focal length of the liquid lens can be changed.

It is preferable to use a liquid lens that can be changed so that the focal distance is infinite. By setting the focal length of the liquid lens to infinity, it is possible to observe the anterior segment in the same manner as when the front lens is separated from the optical path of the observation optical system. It is also possible to switch between anterior segment observation and posterior segment observation while being inserted into the light path.
Hereinafter, an example of an embodiment of the present invention using a liquid lens capable of changing the focal distance to infinity will be described in detail with reference to the drawings.

Second Embodiment
FIG. 3 is a schematic view showing the structure of the front lens holder 4 used in the second embodiment of the present invention.
As shown in FIG. 3, the two transparent glass substrates 411 and 412 are disposed at opposing positions. In one glass substrate 411, a transparent electrode 501 having a thickness so as to form a recess is formed. An insulating film 421 is formed on the inner surface of the joined body of the glass substrate 411 and the transparent electrode 501.
The transparent electrode 502 is formed on the inner surface of the other glass substrate 412, and the insulating film 422 is formed on the inner surface of the transparent electrode 502.

As shown in FIG. 3, the polar liquid 601 and the nonpolar liquid 602 are injected into the depression on the glass substrate 411 side. Then, the polar liquid 601 and the nonpolar liquid 602 are sealed by joining the portions where the two insulating films 421 and 422 are in contact with each other with the durable adhesive 45.
Since the polar liquid 601 and the nonpolar liquid 602 do not mix with each other, the interface 6a is formed at the boundary. Since light is refracted at this interface 6 a, a liquid lens can be formed in the front lens holder 4.
In the second embodiment, the thick transparent electrode 501 also serves as a spacer member provided between the transparent substrates 411 and 412.

As shown in FIG. 3, the transparent electrodes 501 and 502 are connected to the voltage amplifier 7 through the conductors 901 and 902. The magnitude of the voltage applied to the transparent electrodes 501 and 502 by the voltage amplifier 7 can be controlled by the controller 8. As described above, by controlling the voltage applied to the transparent electrodes 501 and 502 by the control device 8, it is possible to control the change of the focal length of the liquid lens.
For example, when a voltage is applied between the transparent electrodes 501 and 502, the nonpolar liquid 602 has a dome shape as shown by the solid line in FIG. 3 and light is refracted at the interface 6a, so the liquid lens becomes a convex lens . When no voltage is applied between the transparent electrodes 501 and 502, the interface between the polar liquid 601 and the nonpolar liquid 602 becomes flat as shown by the dotted line in FIG. 3, and the focal length of the liquid lens is infinite. It becomes.
By setting the focal length of the liquid lens to infinity, it is possible to observe the anterior segment as in the case where the front lens is separated from the optical path of the observation optical system, so the front lens holder 4 can be viewed as an observation optical system It is possible to switch between anterior segment observation and posterior segment observation while being inserted into the optical path of

As exemplified in the liquid lens holder used in the first embodiment and the second embodiment, in the present invention, an electrode and an insulating film are provided in this order on the inner surfaces of two opposing transparent substrates. A transparent substrate and a spacer member provided therebetween to form a container transmitting light;
A polar liquid and a nonpolar liquid are sealed in a container to form an interface between the polar liquid and the nonpolar liquid, and a liquid lens having the interface as a refractive surface is formed.
By applying a voltage to the electrodes, the interface can be changed to change the focal length of the liquid lens.

2. Ophthalmic Microscope The ophthalmic microscope of the present invention is an ophthalmic microscope having an observation optical system for observing an eye to be examined, and in addition to the ophthalmic microscope main body, the above-mentioned 1. It has the pre-lens apparatus described in these.
In the present invention, the term "ophthalmic microscope" refers to a medical or examination instrument having an observation optical system including an optical element capable of magnifying and observing an eye to be examined, not only for humans but also for animals. Including the The “ophthalmic microscope” includes, but is not limited to, for example, a fundus camera, a slit lamp, a microscope for ophthalmologic surgery, and the like.

The ophthalmic microscope preferably further includes an illumination optical system, and the return light reflected / scattered from the eye illuminated by the illumination optical system can be magnified and observed by the observation optical system. The illumination optical system is configured to include an optical element for illuminating the subject's eye. The illumination optical system may further include a light source, but may also guide natural light to the eye to be examined.
The “observation optical system” in the present invention can be configured to be divided into a left-eye observation optical system and a right-eye observation optical system, and when parallax is generated in the images obtained by the left and right observation optical systems. Can also be observed stereoscopically by binocular vision.
The “observation optical system” in the present invention may be one in which the observer can directly observe the eye to be examined through an eyepiece lens or the like, or can be observed by receiving light with an imaging device or the like to form an image Alternatively, it may have both functions.

An objective lens is provided on the most eye side of the observation optical system. Then, in the front lens device of the present invention, the front lens holder can be inserted into the optical path of the observation optical system between the objective lens and the eye to be examined.
The pre-lens apparatus preferably has a mechanism that can not only insert the pre-lens holder into the light path of the observation optical system, but can also release it.
However, if the liquid lens held by the front lens holder is a liquid lens capable of changing the focal length to infinity, the front lens holder is inserted in the optical path of the observation optical system. It is also possible to switch between anterior eye observation and posterior eye observation.

FIG. 4 is a schematic view showing the relationship between the distance between the objective lens and the subject's eye when the anterior lens holder is switched to switch between anterior segment observation and posterior segment observation.
In the anterior segment observation, as shown in FIG. 4A, the anterior segment of the subject eye 11 is located at the focal point position (front focal point position) U0 closer to the subject eye 11 than the objective lens 13 of the observation optical system. The distance H2 between the objective lens 13 and the eye 11 to be examined is set so as to be positioned. Assuming that the focal distance from the objective lens 13 of the observation optical system is F1, H2 = F1.
On the other hand, as shown in FIG. 4 (B), in the posterior eye observation, the distance H2 'between the objective lens 13 and the eye 11 to be examined is set longer, and between the front focal position U0 and the eye 11 to be examined. The front lens holder 4 is arranged. The liquid lens 6 held by the front lens holder 4 is arranged so as to guide the light of the observation optical system as parallel light to the lens 11b of the eye to be examined and to focus on the retina 11a via the lens 11b. Assuming that the focal length of the liquid lens 6 is F2, typically, H2 '≒ F1 + 2 × F2.

As apparent from comparison between the distance H2 between the objective lens 13 and the eye 11 in FIG. 4A and the distance H2 ′ between the objective lens 13 and the eye 11 in FIG. 4B, When inserting the holder 4, it is necessary to increase the distance between the objective lens 13 and the eye to be examined 11, and the ophthalmic microscope main body is taken along the optical axis each time the front lens holder 4 is inserted and removed. You need to move it up and down. The vertical movement of the ophthalmic microscope main body can also be performed manually or automatically, but it is complicated to perform the movement every time the front lens holder 4 is inserted and removed.
Therefore, when performing anterior segment observation, as shown in FIG. 4C, the front lens holder 4 is separated from the optical path, and the objective auxiliary lens 17 formed of a concave lens is inserted into the optical path. The focal length is increased to match H2 '. Then, when performing the posterior eye observation, as shown in FIG. 4B, the objective auxiliary lens 17 is separated from the light path, and the front lens holder 4 is inserted into the light path. By using the objective auxiliary lens 17 in this manner, the distance between the objective lens 13 and the eye 11 to be examined becomes H2 'in any of the anterior eye observation and the posterior eye observation, and the ophthalmic microscope main body is vertically There is no need to move to

Therefore, in the ophthalmic microscope of the present invention, it is preferable to have an objective auxiliary lens used to adjust the focal position on the side of the eye to be examined rather than the objective lens of the observation optical system.
Here, the objective auxiliary lens is preferably a lens having negative power capable of increasing the focal length. A lens having negative power is usually a lens also called a concave lens.
Further, in the ophthalmic microscope of the present invention, it is preferable to have a switching mechanism capable of automatically inserting or removing the objective auxiliary lens in conjunction with insertion or removal of the front lens holder.

FIG. 5 is a schematic view showing the relationship between the distance between the objective lens and the eye to be examined when the focal length of the liquid lens changes.
FIG. 5A is a view showing a state in which the front lens holder 4 is inserted into the light path for the rear eye observation, and has the same positional relationship as FIG. 4B. In FIG. 5A, the distance between the objective lens 13 and the liquid lens 6 is indicated by H1 '. The refractive power of the liquid lens 6 is D.
On the other hand, FIG. 5B shows a state in which the liquid lens 6 is changed to a liquid lens 6 ′ ′ by deforming the liquid lens 6 in the same posterior eye observation. The refractive power D ′ ′ of the liquid lens 6 ′ ′ is a value larger than the refractive power D of the liquid lens 6.

The focal length of the liquid lens 6, 6 ′ ′ is a length that can be determined from the reciprocal of the refractive power, so the liquid in FIG. 5 (B) is better than the focal length F2 of the liquid lens 6 in FIG. The focal length F2 ′ ′ of the lens 6 ′ ′ is shorter. As is apparent from a comparison between FIG. 5A and FIG. 5B, the distances H1 ′ and H1 ′ ′ between the objective lens 13 and the liquid lenses 6 and 6 ′ ′ have short focal lengths (refractive power In the case of FIG. 5 (B) using the liquid lens 6 ′ ′, it is necessary to be shorter than in the case of FIG. 5 (A). Further, in the case of FIG. 5B using the liquid lens 6 ′ ′ having a short focal length (large refractive power), the distances H2 ′ and H2 ′ ′ between the objective lens 13 and the eye 11 to be examined are also It is necessary to make it shorter than the case of FIG. 5 (A).
Therefore, when the focal length of the liquid lens is changed, it is necessary to adjust the distance between the objective lens and the front lens holder, and at the same time, the ophthalmic microscope main body is moved up and down to move the objective lens and the subject. The distance between optometrists also needs to be adjusted.

Therefore, when the focal length of the liquid lens is changed, as shown in FIG. 5C, the focal length is increased by inserting the objective auxiliary lens 17 ′ ′ ′ consisting of a concave lens into the light path. , F1 ′ ′ ′ = H2′−2 × F2 ′ ′. Then, the distance between the objective lens 13 and the eye 11 to be examined matches H2 '. As a result, even when the focal length of the liquid lens is changed, the distance between the objective lens 13 and the eye 11 to be examined may remain H2 ', and it is not necessary to move the microscope body up and down.
However, the distance between the objective lens 13 and the liquid lens is H1 ′ when the focal length of the liquid lens is F2 (the refractive power is D), and the focal length of the liquid lens is F2 ′ ′ In the case where the refractive power is D ′ ′), it is necessary to adjust so as to be H1 ′ ′ ′.

Furthermore, when the focal length of the liquid lens is set to a third value which is neither F2 nor F2 ′ ′, the distance between the objective lens and the eye to be examined is constant by using a third objective auxiliary lens corresponding thereto. Can be
Therefore, in the ophthalmic microscope of the present invention, when changing the focal length of the liquid lens to three types, it is preferable to have at least three objective auxiliary lenses for adjusting the focal length. When the focal length of the liquid lens is changed to n types (n ≧ 3), it is preferable to have n or more objective auxiliary lenses.
In the following, an example of an embodiment of the inventive ophthalmic microscope using a front lens arrangement and an objective auxiliary lens will be described in detail with reference to the drawings.

Third Embodiment
6 to 11 are drawings schematically showing a third embodiment of the present invention.
FIG. 6 is a schematic side view of the ophthalmologic microscope 2 and FIG. 7 is a schematic front view of the same, showing the observation of the anterior segment (e.g. cornea, anterior capsule, sclera etc.) of the eye 11 to be examined. ing. Further, FIG. 8A is a schematic view of an observation optical system 300 (an observation optical system in which an objective auxiliary lens is provided on the side of the eye to be examined of the objective lens) of the ophthalmic microscope of FIGS.
As shown in FIG. 6, the ophthalmologic microscope 2 includes an illumination optical system 1800 (not shown in FIG. 7) in addition to the observation optical system 300.
The observation optical system 300 can observe an observation target (the eye 11 in FIGS. 6 and 7). As shown in FIG. 6, the illumination optical system 1800 can illuminate a portion to be observed of the eye 11 to be examined.
In FIG. 6 and FIG. 7, the observation optical system has the front focal position U0 in front of the subject eye 11.

As clearly shown in FIG. 7, the observation optical system 300 has a right-eye observation optical system 300R and a left-eye observation optical system 300L. In FIG. 6, the entire configuration is shown for the right-eye observation optical system 300R, and only the objective lens 13 shared with the right-eye observation optical system 300R is shown for the left-eye observation optical system 300L. .
As shown in FIG. 7, the front lens holder 4 has a liquid lens 6 inside. The front lens holder 4 can be moved and inserted into the light path of the observation optical system, but is separated from the light path of the observation optical system during the anterior segment observation.
Further, as clearly shown in FIG. 7, the optical axis O-300R of the right-eye observation optical system 300R and the optical axis O-300L of the left-eye observation optical system 300L pass through the objective lens 13 respectively.
In the present embodiment, the illumination optical system 1800 and the observation optical system 300 are housed in the ophthalmic microscope main body 12. In FIG. 6 and FIG. 7, the ophthalmic microscope main body 12 is shown by a dashed dotted line.

The illumination optical system 1800 shown in FIG. 6 includes an illumination light source 19, an optical fiber 1801, an output light aperture 1802, a condenser lens 1803, an illumination field aperture 1804, a collimator lens 1805 and a reflection mirror 1806. The optical axis of the illumination optical system 1800 is indicated by O-1800.
As shown in FIG. 6, the illumination light source 19 is provided outside the ophthalmic microscope main body 12 in the present embodiment. One end of an optical fiber 1801 is connected to the illumination light source 19. The other end of the optical fiber 1801 is disposed at a position facing the outgoing light stop 1802 of the ophthalmic microscope main body 12. The illumination light emitted from the illumination light source 19 is guided by the optical fiber 1801 and enters the condenser lens 1803 through the exit light diaphragm 1802.
The exit light stop 1802 acts to block a partial area of the exit of the optical fiber 1801. When the blocking area by the outgoing light diaphragm 1802 is changed, the outgoing area of the illumination light is changed. Thus, it is possible to change the irradiation angle by the illumination light, that is, the angle between the incident direction of the illumination light to the eye 11 to be examined and the optical axis of the objective lens 13.

The illumination field stop 1804 is provided at a position (position of x) optically conjugate with the front focal position U 0 of the objective lens 13. The collimator lens 1805 converts the illumination light having passed through the illumination field stop 1804 into a parallel light flux. The reflection mirror 1806 reflects the illumination light collimated by the collimator lens 1805 toward the objective lens 13. The light reflected by the reflection mirror 1806 is transmitted through the objective lens 13 and irradiated to the eye 11 to be examined.
The illumination light emitted to the subject eye 11 is reflected and scattered by the tissue of the retina. The reflected and scattered return light (also referred to as “observation light”) passes through the objective lens 13 and is incident on the observation optical system 300.

The observation optical system 300 is used to observe the subject eye 11 illuminated by the illumination optical system 1800 through the objective lens 13.
As shown in FIGS. 6 and 7, a variable magnification lens system 301 (lenses 301a, 301b, and 301c), a beam splitter 302 (a beam splitter for acquiring image information for displaying a television camera), an imaging lens 303, An image erecting prism 304, an eye width adjusting prism 305, a field stop 306, and an eyepiece lens 307 are included. The optical axis of the observation optical system 300 is indicated by O-300.

  As shown in FIG. 7, the beam splitter 302 of the right-eye observation optical system 300R separates a part of the observation light guided from the subject eye 11 along the right-eye observation optical system and takes a photographing optical system. Lead to 2000. The imaging optical system 2000 includes an imaging lens 2001, a reflection mirror 2002, and a television camera 2003. The image information acquired by the television camera 2003 is sent to a monitor (not shown) and displayed.

As shown in FIGS. 6 and 7, the image erecting prism 304 converts an inverted image into an erected image. The eye width adjusting prism 305 is an optical element for adjusting the distance between the left and right observation light paths according to the eye width (the distance between the left eye and the right eye) of the observer. The field stop 306 blocks the peripheral region in the cross section of the observation light to limit the observer's field of view. The field stop 306 is provided at a position (x position) conjugate with the front focal position U0 of the objective lens 13.
The right-eye observation optical system 300R and the left-eye observation optical system 300L may be configured to include a stereo variator configured to be insertable into and removable from the light path. The stereo variator is an optical axis position change element for changing the relative position of the optical axes O-300L and O-300R of the left and right observation optical systems guided by the left and right variable magnification lens systems 301, respectively. The stereo variator, for example, is retracted to a retraction position provided on the observer side with respect to the observation light path.

In the ophthalmologic microscope 2 of FIGS. 6 and 7, the observation optical system has a front focal position (indicated by U0 in front of the eye 11 when no lens is present between the objective lens 13 and the eye 11). )have. In the ophthalmic microscope 2, an objective auxiliary lens 17 is provided on the eye 11 side of the objective lens 13.
The objective auxiliary lens 17 can be set (inserted) at a position near the objective lens 13 between the front focal position U0 and the objective lens 13 or can be released from the position. The objective auxiliary lens 17 is selected such that the in-focus point when it is set is the first focal point (U1) which is the anterior eye position of the eye to be examined.
FIG. 8A shows the case where the objective auxiliary lens 17 is provided on the side of the eye 11 of the objective lens 13 in the observation optical system when observing the anterior segment of the eye 11 to be examined. In the present invention, as shown in FIG. 8B, the objective auxiliary lens 17 can be provided on the opposite side of the objective lens 13 to the eye 11 side to observe the anterior segment of the eye 11 to be examined.

FIG. 9 is a side view corresponding to FIG. 6 showing how the posterior eye portion (eg, retina) of the eye 11 to be examined is observed in the apparatus described with reference to FIGS. 6 and 7. 10 is a front view corresponding to FIG. 7, and FIG. 11 (A) is a schematic view corresponding to FIG. 8 (A).
9 and 10, the objective auxiliary lens 17 is released from the optical path of the observation optical system. The front lens holder 4 is set at a position closer to the subject eye 11 than the front focal position U0, and the focal point (second focus U2) through the lens of the subject eye 11 when set is: The position of the retina of the subject eye 11 (posterior eye position) is set.
Even when the objective auxiliary lens 17 is provided on the opposite side of the objective lens 13 to the subject's eye 11 (see FIG. 8B), when observing the back eye part of the subject's eye 11, FIG. It is necessary to release the objective auxiliary lens 17 as shown in FIG.

1: Pre-lens device 2: Ophthalmic microscope 300: Observation optical system 300R: Right-eye observation optical system 300L: Left-eye observation optical system 301: Variable-magnification lens system 302: Beam splitter 303: Imaging lens system 304: Image erecting prism 305: Eye width adjusting prism 306: Field stop 307: Eyepiece lens 4: Head lens holder 411, 412: Glass substrate 421, 422: Insulating film 431, 432: Water- and oil-repellent film 44: Glass ring member 45: durable adhesive 46: sealing member 501, 502: transparent electrode 6, 6 ′ ′: liquid lens, front lens 6a: interface 601: nonpolar liquid 602: polar liquid 7: voltage amplifier 8: control device 901 , 902: lead 1001: first support arm 1002: second support arm 1003: pivot axis 1004: support bracket 1005: pivot Lever 1006: Linking arm 1007: Lens position adjusting device 11: Eye 11a to be examined: Retina 11b: Lens 12: Ophthalmic microscope main body 13: Objective lens 14: Lens barrel 15: Inverter portion 16: Switching lever 17, 17 ′ ′ ': Objective auxiliary lens 1800: illumination optical system 1801: optical fiber 1802: outgoing light diaphragm 1803: condenser lens 1804: illumination field diaphragm 1805: collimating lens 1806: reflection mirror 19: illumination light source 2000: photographing optical system 2001: imaging lens 2002: Reflection mirror 2003: TV camera D, D ′ ′: refractive power of liquid lens F1, F1 ′, F1 ′ ′: focal length from objective lens F2, F2 ′ ′: focus of liquid lens (front lens) Distance H1 ′, H1 ′ ′, H1 ′ ′ ′: distance H2 between objective lens and liquid lens 2 ′, H2 ′ ′: distance O-300 between the objective lens and the eye to be examined: optical axis O-300R of the observation optical system: optical axis O-300L of the observation optical system for the right eye: light of the observation optical system for the left eye Axis O-1800: Optical axis U0 of illumination optical system: Front focal position U1: First focal point U2: Second focal point

Claims (10)

In a front lens device used in an ophthalmic microscope having an observation optical system for observing an eye to be examined,
A front lens holder for holding a liquid lens;
And a focal length control mechanism for changing a focal length of the liquid lens by changing a shape of the liquid lens.   The focal length control mechanism includes an electrode provided around the liquid lens, a voltage amplifier for applying a voltage to the electrode through a lead, and a control device for controlling the voltage of the voltage amplifier. The front lens apparatus according to claim 1. The front lens holder includes a light transmitting container;
By enclosing a polar liquid and a nonpolar liquid in the container, an interface is formed between the polar liquid and the nonpolar liquid, and a liquid lens having the interface as a refractive surface is formed. The front lens device according to claim 1 or 2. An electrode and an insulating film are provided in this order on the inner surface of two opposing transparent substrates, and a container transmitting light is formed by the transparent substrates and a spacer member provided therebetween.
A polar liquid and a nonpolar liquid are enclosed in the container to form an interface between the polar liquid and the nonpolar liquid, and a liquid lens having the interface as a refractive surface is formed.
The front lens apparatus according to claim 2 or 3, wherein the focal distance of the liquid lens is changed by changing the interface by applying a voltage to the electrode.   The pre-lens apparatus according to any one of claims 1 to 4, wherein the liquid lens is a liquid lens capable of changing a focal distance to infinity. In an ophthalmic microscope having an observation optical system for observing an eye to be examined,
An ophthalmic microscope comprising the front lens device according to any one of claims 1 to 5.   An objective auxiliary lens that is insertable into and removable from the optical axis of the observation optical system and used to adjust the focal position closer to the eye to be examined than the objective lens of the observation optical system is provided. The ophthalmic microscope according to 6.   The ophthalmic microscope according to claim 7, wherein the objective auxiliary lens is a lens having a negative power.   The ophthalmic microscope according to claim 7, further comprising a switching mechanism that inserts, removes, or replaces the objective auxiliary lens in conjunction with a change in focal length of the liquid lens. The ophthalmic microscope according to any one of claims 7 to 9, wherein the focal length of the liquid lens is changed to at least n types and at least n objective auxiliary lenses are provided.