JPH0856895A - Optical system of endoscope - Google Patents

Abstract

PURPOSE: To provide an optical system of an endoscope generating no mist or waterdrop bringing about trouble in observation on its inner surface even when the endoscope is disinfected by boiling or sterilized by steam. CONSTITUTION: In this optical system of an endoscope composed of one or a plurality of optical element.s 11-14, hydrophilic treatment for obtaining an affinity for water is applied to the whole or a part of at least the surfaces not exposed to the outside of the optical elements 11-14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system of an endoscope having an optical system composed of one or a plurality of optical elements.

[0002]

2. Description of the Related Art An objective optical system or an eyepiece optical system of an endoscope is constructed by combining one or a plurality of lenses, lens groups, or optical elements such as prisms.

Since the outer surface of the objective lens exposed to the outside is easily fogged by moisture in the body when it is inserted into the body cavity, various antifogging measures have been considered.

[0004]

When the endoscope is boiled and sterilized or steam sterilized and taken out into the room, it looks like a white mist. This fog is 30
If it is left for about 1 hour from the minute, it will gradually clear and a normal observation image can be obtained. However, since the endoscope cannot be used during that time, the examination cannot be completed and it is extremely inconvenient.

If boiled sterilization or steam sterilization is repeated or carried out continuously for a long period of time, large water droplets instead of fog will appear in the optical system, and the observation image of the endoscope will be seriously damaged.

When the positions where such fog or water droplets adhere are examined, it has been confirmed that the surfaces of the optical elements such as a plurality of lenses face each other with the air layer in between.

This phenomenon occurs as soon as the endoscope in the high temperature region is taken out to the room temperature region for boiling sterilization or steam sterilization, so that the water vapor in the air in the sealed space between the optical elements is rapidly cooled. Therefore, it is judged that it will be exposed.

Therefore, it is conceivable to fill the sealed space between the optical elements with an inert gas such as helium, neon, argon, xenon, or radon that does not contain water vapor, nitrogen, carbon dioxide, air, or the like.

However, the objective lens of an endoscope has a diameter of 1 mm.
Since many of them are very small as shown below, the sealed space is also very small, and it is extremely difficult to enclose a gas having no water vapor component therein.

It is also conceivable to manufacture parts near the optical element with a substance having a large heat capacity, but since the parts of the endoscope are very small, it is not effective enough to prevent the generation of fog and water droplets. I can't get it.

Therefore, an object of the present invention is to provide an optical system of an endoscope in which fog or water droplets that hinder observation are not generated on the inner surface even when the endoscope is sterilized by boiling or steam sterilization. To do.

[0012]

In order to achieve the above object, an endoscope optical system of the present invention is an endoscope optical system composed of one or a plurality of optical elements. At least all or part of the surface not exposed to the outside is subjected to a hydrophilic treatment for obtaining an affinity for water.

In the above hydrophilic treatment, after coating the surface of the optical element with a hydrophilic substance, the hydrophilic substance is wiped off to the extent that strong reflection does not occur on the coated surface to make the surface of the optical element hydrophilic. Alternatively, the surface of the optical element may be modified to be hydrophilic by generating active oxygen on the surface of the optical element.

[0014]

Embodiments will be described with reference to the drawings. FIG. 1 shows a distal end of an insertion portion of an endoscope, and an objective optical system 10 is arranged at a front end portion of a plastic tip body 1 so as to face forward.

In the objective optical system 10, first to fourth lenses 11 to 14 are coaxially arranged, and the third and fourth lenses 13 and 14 are cemented to form one lens group. There is.

The objective optical system 10 is fitted in a metallic lens frame 2, a brightness diaphragm 3 is sandwiched between a first lens 11 and a second lens, and a second lens 12 is provided.
A spacing ring 4 is sandwiched between the third lens 13 and the third lens 13, and is fixed by caulking with a lens frame 2 from the front end and the rear end of the objective optical system 10. An adhesive is applied to the caulked portion, and the inside of the lens frame 2 is sealed in a completely airtight state.

In this way, the objective optical system 10 is independently assembled in the lens frame 2 as an objective lens unit, and the objective lens unit is further attached to the unit fixing barrel 5.
Is joined to the tip of. Then, the optical fiber bundle 6 for image transmission is fixed to the unit fixing cylinder 5 while adjusting the focus, and the observation optical system unit is completed.

The observation optical system unit assembled outside the tip body 1 in this manner is finally adhered and fixed to the tip body 1, but in order to prevent the metal lens frame 2 from being exposed on the surface, The tip portion is arranged at a position slightly recessed from the surface of the tip body 1, and the recess is filled with a black adhesive 7.

On the surface of each of the lenses 11 to 14 of the objective optical system 10, except for the joint surface of the third and fourth lenses 13 and 14, a hydrophilic substance having an affinity for water is used. It is applied before being incorporated into the frame 2.

The hydrophilic substance is wiped cleanly after application to the extent that strong reflection does not occur on the application surface. As a result, as shown by the thick line in FIG. 1, the hydrophilic ultra-thin film layer is formed on the surface of each lens 11, 12, 13, 14.

In this example, a surfactant was used as the hydrophilic substance. A surfactant is a compound that has both a hydrophilic group that has polarity and is soluble in water or has an affinity for water and a lipophilic group or a hydrophobic group that is non-polar and soluble in or has affinity for an organic solvent in the molecule at the same time. Is.

Structurally classified, there are anionic surfactants, cationic surfactants, amphoteric surfactants, etc. as ionic surfactants that dissociate into ions, and nonionic surfactants that do not dissociate into ions. There is.

(Experimental example) An experiment was carried out using a hydrophilic coating liquid prepared with the following composition. Nonionic surfactant (polyoxyethylene, sorbitan alkylate) Anionic surfactant (alkanolamine sulfate) Modified siloxane polyhydric alcohol water.

This coating solution was applied to each lens surface, and the lens surface was wiped up with a lens paper or the like so as not to be visually fogged or glaring, and then incorporated into the lens frame 2.

Then, the objective optical system 10 that has undergone this processing
The endoscope attached with and the untreated endoscope were immediately exposed to room temperature 30 minutes after boiling for 20 times, and the endoscopic image was observed each time.

The results are shown in the following table.

[0027]

[Table 1]

Although a surfactant was used as the hydrophilic substance in the above examples, the present invention is not limited to this, and a hydrophilic vinyl compound, a silane compound or the like may be applied.

Further, although it cannot be used for a lens surface on which a multi-layer or single-layer antireflection film or a transparent film is formed, the wettability of water on the surface of the optical glass is improved by irradiating the lens with ultraviolet rays. Turned out to be.

When the lens surface was irradiated for 10 minutes using a low pressure mercury lamp with an output of 650 W, which emitted ultraviolet rays having wavelengths of 184.9 nm and 253.7 nm, the water wettability index in terms of adhesion was 20 dyne / cm. 50dyne /
As a result of the experiment, good results similar to those obtained by coating the hydrophilic material were obtained with respect to the haze.

This is due to the irradiation of ultraviolet rays of two wavelengths,
It is considered that active oxygen [O] is generated due to the decomposition of O ₂ and the generation and decomposition of O ₃ to improve the cleaning property of the glass surface or partially modify it.

Therefore, the treatment is not limited to the ultraviolet irradiation, and any treatment can be used as long as it is a treatment for generating active oxygen [O] on the surface of the optical lens.
Plasma treatment, glow discharge, corona discharge and the like can also be used.

As a method for coating the lens surface with a hydrophilic substance, a mixture of hydroxyethyl methacrylate and polyethylene dimethacrylate is applied to the lens surface,
Alternatively, it was attempted to apply a film containing polyvinyl alcohol as a main component to the lens surface and heat-treat at 150 ° C. for about 5 minutes to prepare a coating film of a hydrophilic material.

However, it is very difficult to apply it to a lens with a size of 1 mm or less, and in the drying process, considerable problems occur such as dust adhering to the coating portion and the coating being not evenly applied. .

The present invention is not limited to the above-mentioned embodiment, and for example, the treatment for obtaining hydrophilicity may not be applied to the surface 11a of the objective optical system 10 which faces the outside, and the objective 11a is not required to be treated. It may be applied to a part of the inner surface of the optical system 10.

The optical element may be a lens, a prism, an optical filter, a simple plane parallel plate, an end face of an optical fiber bundle, or the like, and the optical system may be formed by a single optical element.

Further, the object of application of the present invention is not limited to the objective optical system, but may be applied to the eyepiece optical system, and is applied to an optical system of a so-called electronic endoscope using a solid-state image pickup device for transmitting an observation image. You may apply.

[0038]

According to the present invention, the endoscope is boiled and sterilized by simply coating the surface of the optical element with a hydrophilic substance and wiping it off, or by irradiating it with a hydrophilic treatment such as irradiation with ultraviolet rays. When steam sterilized, it is possible to prevent fog and water droplets that hinder observation from occurring in the optical system, which can be performed at low cost without deteriorating the optical performance.

[Brief description of drawings]

FIG. 1 is a side sectional view of an insertion portion of an embodiment.

[Explanation of symbols]

 2 Lens Frame 2 10 Objective Optical System 11-14 Objective Lens

Claims (3)

[Claims] 1. An optical system of an endoscope comprising one or a plurality of optical elements, for obtaining an affinity for water to at least all or a part of a surface of the optical element which is not exposed to the outside. An optical system for an endoscope, which has been subjected to a hydrophilic treatment. 2. The hydrophilic treatment applies a hydrophilic substance to the surface of the optical element, and then wipes off the hydrophilic substance to such an extent that strong reflection does not occur on the coated surface to make the surface of the optical element hydrophilic. The optical system for an endoscope according to claim 1, wherein 3. The optical system for an endoscope according to claim 1, wherein the hydrophilic treatment produces active oxygen on the surface of the optical element to modify the surface of the optical element to be hydrophilic.