JP4190229B2 - Optical system and endoscope - Google Patents

Description

【００８８】
表１に示すように、実施例１〜１８の電子内視鏡（本発明の内視鏡）は、いずれも被写体の画像の画質の低下が防止され、繰り返し施される滅菌処理に耐え得るものであった。
【００８９】
これに対し、比較例１〜４の電子内視鏡は、いずれも滅菌処理を繰り返すこと、または、高湿度下に長時間放置することにより、早い段階で被写体の画像の画質が低下し、極めて見難いものとなってしまった。
【００９０】
【発明の効果】
以上述べたように、本発明によれば、高湿度の環境下に曝された場合でも、乾燥剤の除湿効果により、曇りや結露が生じ難い光学系を提供することができる。
【００９１】
また、乾燥剤として、水分子を結晶水として分子構造内に取り込み得る吸湿物質、特に、硫酸マグネシウムを主成分とするものを用いることにより、前記効果がより向上する。
【図面の簡単な説明】
【図１】本発明の光学系を適用した電子内視鏡（電子スコープ）を示す全体図である。
【図２】図１に示す電子内視鏡の先端部を示す縦断面図である。
【符号の説明】
１０ 電子内視鏡
１ 挿入部可撓管
３ 撮像手段
３１ 撮像素子
３１１ 信号線
３２ 対物レンズ系
３２０ 対物レンズ
３２１ 第１レンズ
３２２ 第２レンズ
３２３ 第３レンズ
３２４ 第４レンズ
３２５ 支持体
３２６ 枠部材
３２７ 間隔リング
３２８ 光学フィルター
３３ 孔部
３３１ 先端開口
４ 照明手段
４１ 光ファイバー束
４２ 平凹レンズ
５ 湾曲部
５１ 先端部
６ 操作部
６１、６２ 操作ノブ
７ 接続部可撓管
８ 光源差込部
８１ 光源用コネクタ
８２ 画像信号用コネクタ
８３ 信号処理回路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical system and an endoscope.
[0002]
[Prior art]
In the medical field, endoscopes are used for examination and diagnosis of the digestive tract and the like. This endoscope has an insertion portion (endoscopic flexible tube) to be inserted into a body cavity, and an operation portion that is installed on the proximal end side of the insertion portion and performs a bending operation on the distal end portion of the insertion portion. is doing. The endoscope has a connection portion that extends from the operation portion and is connected to the light source device and the control device.
[0003]
The insertion portion includes a flexible tube having flexibility so that the insertion portion can be inserted into a bent body cavity and follow the bending portion, and a bending portion that is bent at the distal end side thereof.
[0004]
In addition, observation means including an objective lens is provided inside the distal end portion of the bending portion.
[0005]
However, if moisture enters and remains in the insertion portion (particularly the distal end of the bending portion) during, for example, sterilization of an endoscope, the objective lens is clouded or dewed due to a temperature difference between the inside and the outside of the insertion portion. As a result, there is a problem that observation of the observation site becomes extremely difficult.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide an optical system in which fogging and condensation are unlikely to occur even when exposed to a high humidity environment, and an endoscope including such an optical system.
[0007]
[Means for Solving the Problems]
Such an object is achieved by the present inventions (1) to ( 8 ) below.
[0008]
(1) An optical system composed of a plurality of optical components including an optical component that does not require optical transparency,
Drying at least part of the optical component that does not require light transmission, in the form of a powder having an average particle diameter of 1 to 30 μm , mainly composed of a hygroscopic substance that can irreversibly incorporate water molecules into the molecular structure as crystal water. It is composed of a resin material containing an agent ,
The optical system, wherein the hygroscopic substance is magnesium sulfate represented by MgSO ₄ · nH ₂ O (where 0 ≦ n ≦ 3), and the resin material is polyphenylene sulfide .
[0009]
Thereby, even when exposed to a high humidity environment, clouding and condensation are unlikely to occur.
[0010]
(2) An optical system comprising a lens and a member bonded to the lens,
At least a part of the member bonded to the lens contains a powdery desiccant having an average particle diameter of 1 to 30 μm mainly composed of a hygroscopic substance capable of irreversibly incorporating water molecules into the molecular structure as crystal water. is obtained by a resin material,
The optical system, wherein the hygroscopic substance is magnesium sulfate represented by MgSO ₄ · nH ₂ O (where 0 ≦ n ≦ 3), and the resin material is polyphenylene sulfide .
[0011]
Thereby, even when exposed to a high humidity environment, clouding and condensation are unlikely to occur.
[0012]
(3) The optical system according to (2), wherein the member bonded to the lens is a support member for the lens.
[0013]
Thereby, it is possible to prevent an increase in the number of parts and an accompanying increase in the size of the optical system.
[0014]
(4) The optical system according to (2) or (3), wherein the lens is an objective lens.
Thereby, observation of an observation part can be performed suitably.
[0015]
(5) The optical system according to any one of (2) to (4), wherein the lens is an endoscope lens.
The optical system of the present invention is preferably applied to an endoscope lens system.
[0016]
(6) The optical system according to any one of (1) to (5), wherein the content of the desiccant is 1 to 40 wt%.
Thereby, the inside or the vicinity of the optical system can be made sufficiently low in humidity.
[0017]
(7) The optical system according to any one of (1) to (6), wherein the hygroscopic substance does not release moisture even after a water molecule is taken in, due to a change in a use environment of the optical system.
[0018]
Thereby, even when the optical system is exposed to a high humidity environment, the humidity inside the optical system can be more reliably maintained at a low level.
[0024]
( 8 ) An endoscope comprising the optical system according to any one of (1) to ( 7 ).
[0025]
The endoscope of the present invention can continuously obtain a clear image of a subject even when exposed to a high humidity environment.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an optical system and an endoscope of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
[0027]
FIG. 1 is an overall view showing an electronic endoscope (electronic scope) to which the optical system of the present invention is applied, and FIG. 2 is a longitudinal sectional view showing a distal end portion of the electronic endoscope shown in FIG. In the following description, in FIG. 1, the upper side is referred to as “base end” and the lower side is referred to as “tip”. In FIG. 2, the left side is the distal direction, and the right side is the proximal direction.
[0028]
An electronic endoscope 10 shown in FIG. 1 includes a bending portion 5 at a distal end, a long insertion portion flexible tube 1 having flexibility (flexibility), and a proximal end portion of the insertion portion flexible tube 1. Provided on the distal end side of the connection portion flexible tube 7, an operation portion 6 that is operated by the operator and operates the entire electronic endoscope 10, a connection portion flexible tube 7 connected to the operation portion 6, And the light source insertion portion 8 thus formed.
[0029]
The insertion portion flexible tube 1 is used by being inserted into a lumen of a living body. As shown in FIG. 2, the insertion portion flexible tube 1 includes an illumination unit 4 that irradiates a subject with illumination light, and an imaging unit 3 that captures an image of the subject.
[0030]
The illumination unit 4 includes a pair of optical fiber bundles (light guides) 41 and 41 disposed along the longitudinal direction of the insertion portion flexible tube 1 (and the connection portion flexible tube 7), and a distal end portion of the optical fiber bundle. Plano-concave lenses (projection lens systems) 42 and 42 are provided.
[0031]
The imaging means 3 has an objective lens system (optical system) 32 and an imaging element (CCD image sensor) 31 installed on the base end side of the objective lens system 32, and these are the distal end portion of the bending portion 5. It is installed in the hole 33 formed in 51. The image sensor 31 is connected to a signal line 311 arranged along the longitudinal direction of the insertion portion flexible tube 1 (and the connection portion flexible tube 7).
[0032]
An operation unit 6 is provided at the proximal end of the insertion portion flexible tube 1. The operation unit 6 is provided with operation knobs 61 and 62 on its side surface. When the operation knobs 61 and 62 are operated, a wire (not shown) disposed in the insertion portion flexible tube 1 is pulled, and the bending portion 5 is bent in four directions, and the directions can be changed. .
[0033]
Further, a connecting portion flexible tube 7 is connected to the operation portion 6. The optical fiber bundle 41 and the signal line 311 pass through the connecting portion flexible tube 7 and are connected to the light source insertion portion 8.
[0034]
The light source insertion unit 8 has a signal processing circuit 83 for processing an image signal therein. The light source insertion portion 8 has a light source connector 81 and an image signal connector 82 at the distal end thereof.
[0035]
Each optical fiber bundle 41 is connected to a light source connector 81. The signal line 311 is connected to the signal processing circuit 83, and the signal processing circuit 83 is connected to the image signal connector 82.
[0036]
These image signal connector 82 and light source connector 81 are respectively connected to a light source processor device (not shown). A monitor device (not shown) is connected to the light source processor device.
[0037]
In the electronic endoscope 10 having such a configuration, when the light source insertion unit 8 is connected to the light source processor device and the light source processor device is operated, light (illumination light) emitted from the light source processor device is converted into a light source connector. The light enters the optical fiber bundle 41 through 81. This light passes through the optical fiber bundle 41 and exits from the tip of the optical fiber bundle 41.
[0038]
The emitted light passes through the plano-concave lens 42 and is irradiated to the observation site (subject). At this time, the emitted light passes through the plano-concave lens 42 and is diffused and uniformed. As a result, the electronic endoscope 10 can illuminate the observation site uniformly over a wide range.
[0039]
The illuminated illumination light is reflected at the observation site and becomes reflected light that forms a subject image. Part of this reflected light is incident on the objective lens system 32. The reflected light is guided so as to form an image on the light receiving surface of the image sensor 31.
[0040]
The image sensor 31 receives the reflected light guided to the light receiving surface. As a result, a subject image is captured. The image sensor 31 outputs an image signal (CCD signal) corresponding to the captured subject image. This image signal is transmitted to the light source insertion unit 8 via the signal line 311.
[0041]
This image signal is input to the signal processing circuit 83 by the light source insertion unit 8. Then, the signal processing circuit 83 performs predetermined signal processing on the image signal. The image signal subjected to this processing is output to the light source processor device via the image signal connector 82.
[0042]
The output image signal is converted into a predetermined television signal by the light source processor. Therefore, when the monitor device is connected to the light source processor device, a television signal is input to the monitor device. As a result, the monitor device displays an image (electronic image) of the subject imaged by the image sensor, that is, a video endoscope monitor image.
[0043]
Next, the objective lens system 32 to which the optical system of the present invention is applied will be described.
The objective lens system 32 shown in FIG. 2 has an objective lens (endoscope lens) 320 composed of four lenses 321 to 324. Specifically, the objective lens system 32 includes a first lens 321 installed at the distal end of the insertion portion flexible tube 1 and the center of the first lens 321 toward the base end side (image forming side). The objective lens 320 includes a second lens 322, a third lens 323, and a fourth lens 324 that are installed so that the axes (optical axes) substantially coincide with each other.
[0044]
The first lens 321 is constituted by a plano-concave lens having a flat front surface and a concave surface on the base end surface (image forming side). The first lens 321 is supported and fixed to the edge of the distal end opening 331 where the hole 33 is opened at the distal end of the bending portion 5 (insertion portion flexible tube 1). It is exposed to the outside of the tube 1.
[0045]
The second lens 322 is a plano-convex lens having a flat tip surface and a convex base surface.
[0046]
The third lens 323 and the fourth lens 324 are composed of cemented lenses.
[0047]
The second lens 322, the third lens 323, and the fourth lens 324 are each supported and fixed (bonded) to a cylindrical support body 325. Further, in this state, the support body 325 is inserted into the hole 33 and supported and fixed (joined) to the inside (hole 33) of the bending portion 5 via the cylindrical frame member 326.
[0048]
An interval ring 327 that defines the interval between the second lens 322 and the third lens 323 is provided.
[0049]
Further, an optical filter 328 that removes a high frequency component from the reflected light guided to the light receiving surface of the image sensor 31 is fixed (fixed) to the distal end surface of the image sensor 31.
[0050]
As described above, in the present embodiment, the objective lens (endoscope lens) 320, the support body 325, the frame member 326, and the spacing ring 327, which respectively support (members respectively joined to) the objective lens (endoscope lens), An objective lens system (optical system) 32 is configured by a plurality of optical components such as the optical filter 328.
[0051]
Each of the lenses 321 to 324 (objective lens 320) and the optical filter 328 are made of a material having optical transparency. Specific examples of the light transmissive material include various glass materials and various resin materials.
[0052]
The support 325, the frame member 326, and the spacing ring 327 are each preferably made of a resin material, particularly a relatively hard resin material. Specific examples thereof include polyethylene, polypropylene, polybutadiene, Polyolefin such as ethylene-vinyl acetate copolymer, polyvinyl chloride, polyurethane, polystyrene, polymethyl methacrylate, polycarbonate, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyester, acrylic resin, ABS resin, AS resin, ionomer, polyacetal , Polyphenylene sulfide, polyether ether ketone and the like.
[0053]
Here, since the electronic endoscope 10 is used repeatedly, cleaning, disinfection, sterilization, etc. are performed after each use. When such cleaning, disinfection, sterilization, and the like are repeatedly performed, moisture may enter and remain inside the electronic endoscope 10 to increase the humidity. Similarly, when used in a high-humidity tropical region, the humidity inside the electronic endoscope 10 may increase with the passage of time of use.
[0054]
In these cases, when the humidity inside the electronic endoscope 10 (especially the hole 33) increases, the temperature difference between the inside and outside of the electronic endoscope 10 causes the objective lens 320, particularly the inner surface of the first lens 321 in particular. As a result, the image quality of the image of the subject is drastically lowered and becomes extremely difficult to see.
[0055]
As an example of the case where a temperature difference occurs between the inside and outside of the electronic endoscope 10 as described above, for example, the following case can be cited.
[0056]
That is, when the insertion portion flexible tube 1 is inserted into a body cavity such as the digestive tract and used, when a contaminated material such as a body fluid adheres to the surface of the first lens 321, the observation visual field is caused by the attachment of the contaminated material. Therefore, an operation of washing away the contaminated material from the surface (front end surface) of the first lens 321 using cleaning water or the like is performed. At this time, the first lens 321 has a temperature close to the body temperature in the body cavity or a temperature slightly higher than the body temperature due to the influence of the image pickup device 31 and the like housed therein, but the washing water is usually heated. Not at room temperature. For this reason, when cleaning water is sprayed on the surface of the first lens 321, the first lens 321 is rapidly cooled. As a result, a temperature difference occurs inside and outside the electronic endoscope 10 (particularly, inside and outside of the first lens 321).
[0057]
Therefore, as a result of intensive studies to make the objective lens 320 (the first lens 321) less susceptible to fogging and condensation, the present inventor has determined that, among the optical components constituting the objective lens system 32 as described above, the support body It came to the conclusion that the members joined to the objective lens 320 such as 325, the frame member 326 and the spacing ring 327 may be made of a material containing a desiccant. The members bonded to these objective lenses 320 are optical components that do not require light transmission (hereinafter referred to as “light non-transmissive components”).
[0058]
Here, if a member that requires light transmission, such as the objective lens 320 and the optical filter 328, is made of a material containing a desiccant, the light transmittance is reduced, and the subject can be imaged. It becomes difficult. In addition, when a member containing a desiccant is separately incorporated in the objective lens system 32, the number of parts may increase and the diameter (enlargement) of the distal end portion 51 of the curved portion 5 may be increased.
[0059]
On the other hand, in the present invention, among the optical components constituting the objective lens system 32, the light non-transparent component is composed of a material containing a desiccant, thereby preventing the above-described disadvantages and the electronic endoscope. 10 is used in high-humidity tropical areas, or repeatedly subjected to cleaning, disinfection, sterilization, etc. (exposed to a high-humidity environment), even if moisture enters and remains inside. The inside of the hole 33 is maintained (held) at a low humidity by the desiccant taking up (absorbing moisture) this moisture. As a result, even when a temperature difference occurs between the inside and the outside of the electronic endoscope 10, it is possible to prevent the object lens 320 (especially the first lens 321) from being fogged or dewed, which is clear. A continuous subject image can be obtained continuously.
[0060]
This desiccant is mainly composed of a hygroscopic substance capable of incorporating water molecules into the molecular structure as crystal water. Such a hygroscopic substance irreversibly incorporates water molecules into its molecular structure. Therefore, the amount of water absorption (moisture absorption) compared to substances that simply hold water molecules by adsorption (for example, silica gel, calcium chloride, zeolite, etc.). In other words, it has an excellent moisture absorption capability (dehumidification effect), and it is difficult to release moisture even when the usage environment changes (for example, temperature change). For this reason, by using the desiccant mainly composed of such a hygroscopic substance, the electronic endoscope 10 can reliably reduce the humidity inside the hole 33 even when exposed to a high humidity environment. Can be maintained.
[0061]
The hygroscopic substance is not particularly limited, and examples thereof include magnesium sulfate, aluminum oxide, barium oxide, calcium oxide, silicon oxide, and the like, and one or more of these can be used in combination. Of these, magnesium sulfate is preferably used as the hygroscopic substance.
[0062]
Magnesium sulfate has the following advantages (1) to (4).
That is, {circle over (1)} is excellent in moisture absorption capacity (for example, the amount of water molecules taken up, the uptake speed, etc.). {Circle around (2)} Since the dispersibility in various resin materials is good, the light non-transparent component can be easily mixed into the constituent material. {Circle around (3)} Since no corrosiveness, deliquescence, etc. are exhibited by moisture absorption, no change in shape occurs in the light non-transmissive part. (4): Crushing is difficult to occur and dust generation is extremely small.
[0063]
The magnesium sulfate is preferably represented by MgSO ₄ · nH ₂ O (where 0 ≦ n ≦ 3). That is, magnesium sulfate can be used in combination of one or more of anhydride, monohydrate, dihydrate, and trihydrate. These magnesium sulfates are particularly excellent in moisture absorption capacity. When magnesium sulfate having a hydrate exceeding 3 hydrate is used, when kneading (mixing) the desiccant and the constituent material of the light non-transparent component as described above, the temperature at the time of kneading is mixed. In some cases, water molecules (crystal water) are released from magnesium sulfate, and it may be difficult to knead the desiccant into the constituent material of the light-impermeable component.
[0064]
Note that the desiccant may be any material that contains the hygroscopic substance as a main component (for example, 70 wt% or more), and may include a substance used as another desiccant (for example, silica gel or the like).
[0065]
The shape of the desiccant may be any, but is preferably a powder. By using a powder desiccant, the desiccant can be kneaded into the constituent material of the light non-transmissive part more easily and reliably, and more uniformly mixed (dispersed) into the constituent material of the light non-transmissive part. )be able to.
[0066]
Moreover, when a desiccant is a powder, the average particle diameter is although it does not specifically limit, It is preferable that it is about 1-30 micrometers, and it is more preferable that it is about 2-20 micrometers. The desiccant having an average particle size in the above range can sufficiently secure the specific surface area, and the moisture absorption capacity is further improved.
[0067]
Although content of a desiccant is not specifically limited, It is preferable that it is about 1-40 wt%, and it is more preferable that it is about 1-25 wt%. If the content of the desiccant is too small, depending on the conditions of the use environment of the electronic endoscope 10 and the like, the inside of the hole 33 may not be sufficiently low in humidity. On the other hand, the content of the desiccant If the amount is too large, the melt viscosity may be lowered depending on the type of constituent material of the light non-transmissive component, and it may be difficult to mold the light non-transmissive component.
[0068]
In addition, in the constituent materials of the light non-transmissive parts, for example, plasticizers, inorganic fillers, pigments, various stabilizers (antioxidants, light stabilizers, antistatic agents, antiblocking agents, lubricants) Various additives such as an X-ray contrast medium may be blended (mixed).
[0069]
In the present embodiment, the case where the support 325, the frame member 326, and the spacing ring 327 are made of a material containing a desiccant has been described, but in the present invention, at least one of these (one member). You may make it comprise with the material containing a desiccant.
[0070]
Further, the light non-transmissive component is not limited to the one that uniformly contains (mixed) the desiccant in its entirety, but contains the desiccant in at least a part thereof (for example, near its surface). I just need it. In this case, a layer containing a desiccant is formed on the non-light-transmitting component, and the content of the desiccant in the layer may be in the above range.
[0071]
In addition, any desired component can be added to the objective lens system 32. For example, an annular member that defines the distance between the edge portion of the distal end opening 331 of the curved portion 5 and the frame member 326 is added, and the annular member is formed of a material containing a desiccant as described above. It may be.
[0072]
The optical system and endoscope of the present invention have been described above, but the present invention is not limited to this, and the configuration of each member (each part) can be replaced with any one having the same function. it can.
[0073]
In the above embodiment, the electronic endoscope has been described. However, it is needless to say that the endoscope of the present invention can be applied to an optical endoscope, and is not limited to medical use. It can also be applied to an endoscope used for (industrial use).
[0074]
In the above embodiment, the optical system according to the present invention is applied to an endoscope lens system, in particular, an objective lens system. However, the eyepiece lens system of the endoscope or irradiation for irradiating illumination light is described. The present invention may be applied to a lens system, and may be applied not only to an endoscope body but also to a camera lens system, a lens system of an endoscope accessory, and the like.
[0075]
【Example】
Next, specific examples of the present invention will be described.
[0076]
(Example 1)
First, as a desiccant, using a polyphenylene sulfide containing a powder composed of MgSO ₄ · 2H ₂ O (average particle diameter 5 μm) (Toray Industries, Inc., Torelina A504), a support as described above, A frame member and a spacing ring were produced.
In addition, content of the desiccant was 1 wt%.
[0077]
Next, using these members, an insertion portion flexible tube as shown in FIG. 2 was produced, and an electronic endoscope (an upper digestive tract endoscope) as shown in FIG. 1 was produced.
[0078]
(Examples 2 and 3)
An electronic endoscope was manufactured in the same manner as in Example 1 except that the content of the desiccant was changed as shown in Table 1.
[0079]
(Examples 4 to 18)
An electronic endoscope was manufactured in the same manner as in Example 2 except that the type of desiccant was changed as shown in Table 1.
[0080]
(Comparative Examples 1-3)
An electronic endoscope was manufactured in the same manner as in Example 2 except that the type of desiccant was changed as shown in Table 1.
[0081]
(Comparative Example 4)
An electronic endoscope was manufactured in the same manner as in Example 1 except that the desiccant was not contained.
[0082]
[Evaluation]
The following evaluations were performed on the electronic endoscopes manufactured in each Example and each Comparative Example.
[0083]
[Durability evaluation by sterilization]
Sterilization treatment with ethylene oxide gas (concentration: 100%, humidity: 70% RH, time: 2 hours 45 minutes) was repeated 200 times.
[0084]
For each electronic endoscope, after each sterilization treatment, the distal end of the insertion portion flexible tube is immersed in warm water of 40 ° C. for 10 minutes, and then cold water of 0 ° C. is sprayed onto the first lens, The image quality of the image was confirmed and evaluated according to the following four-stage criteria.
◎: No change in the image quality of the subject even after 200 sterilization treatments ○: There is a slight decrease in the image quality of the subject image after 200 sterilization treatments Δ: The image quality of the subject image is increased from about 150 sterilization treatments Reduced x: The image quality of the subject has been reduced from about 100 sterilization treatments.
[Durability evaluation by leaving in high humidity environment]
It was left for 500 hours in a high humidity environment (temperature: 40 ° C., humidity: 90% RH).
[0086]
And about each electronic endoscope, after every 10 hours progress, after immersing the front-end | tip part of an insertion part flexible tube in 40 degreeC warm water for 10 minutes, 0 degreeC cold water is injected to a 1st lens, and it is a subject. The image quality of the image was confirmed and evaluated according to the following four-stage criteria.
◎: No change in the image quality of the subject image even after being left under high humidity for 500 hours. ○: There is a slight decrease in the image quality of the subject image after being left under high humidity for 500 hours. △: About 400 hours under high humidity. Table 1 shows that the image quality of the subject image has deteriorated after being left. X: The image quality of the subject image has deteriorated after being left for about 300 hours under high humidity.
[0087]
[Table 1]

[0088]
As shown in Table 1, the electronic endoscopes of the first to 18th embodiments (endoscopes of the present invention) are all capable of withstanding repeated sterilization treatment that prevents deterioration of the image quality of the subject image. Met.
[0089]
On the other hand, all of the electronic endoscopes of Comparative Examples 1 to 4 are repeatedly sterilized, or left for a long time under high humidity, so that the image quality of the subject image is deteriorated at an early stage. It has become difficult to see.
[0090]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an optical system in which fogging and condensation are unlikely to occur due to the dehumidifying effect of the desiccant even when exposed to a high humidity environment.
[0091]
Moreover, the said effect improves more by using as a desiccant the moisture absorption substance which can take in a water molecule in a molecular structure as a crystal water, especially the thing which has magnesium sulfate as a main component.
[Brief description of the drawings]
FIG. 1 is an overall view showing an electronic endoscope (electronic scope) to which an optical system of the present invention is applied.
2 is a longitudinal sectional view showing a distal end portion of the electronic endoscope shown in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Electronic endoscope 1 Insertion part flexible tube 3 Imaging means 31 Imaging element 311 Signal line 32 Objective lens system 320 Objective lens 321 First lens 322 Second lens 323 Third lens 324 Fourth lens 325 Support body 326 Frame member 327 Spacing ring 328 Optical filter 33 Hole portion 331 Tip opening 4 Illuminating means 41 Optical fiber bundle 42 Plano-concave lens 5 Bending portion 51 Tip portion 6 Operation portions 61 and 62 Operation knob 7 Connection portion Flexible tube 8 Light source insertion portion 81 Light source connector 82 Image signal connector 83 Signal processing circuit

Claims (8)

An optical system composed of a plurality of optical components including an optical component that does not require light transmission,
Drying at least part of the optical component that does not require light transmission, in the form of a powder having an average particle diameter of 1 to 30 μm , mainly composed of a hygroscopic substance that can irreversibly incorporate water molecules into the molecular structure as crystal water. It is composed of a resin material containing an agent ,
The optical system, wherein the hygroscopic substance is magnesium sulfate represented by MgSO ₄ · nH ₂ O (where 0 ≦ n ≦ 3), and the resin material is polyphenylene sulfide . An optical system comprising a lens and a member bonded to the lens,
At least a part of the member bonded to the lens contains a powdery desiccant having an average particle diameter of 1 to 30 μm mainly composed of a hygroscopic substance capable of irreversibly incorporating water molecules into the molecular structure as crystal water. is obtained by a resin material,
The optical system, wherein the hygroscopic substance is magnesium sulfate represented by MgSO ₄ · nH ₂ O (where 0 ≦ n ≦ 3), and the resin material is polyphenylene sulfide .   The optical system according to claim 2, wherein the member bonded to the lens is a support member for the lens.   The optical system according to claim 2, wherein the lens is an objective lens.   The optical system according to claim 2, wherein the lens is an endoscope lens.   The optical system according to claim 1, wherein the content of the desiccant is 1 to 40 wt%. The optical system according to any one of claims 1 to 6, wherein the hygroscopic substance is one that does not release moisture even after a water molecule is taken in, due to a change in a use environment of the optical system. An endoscope comprising the optical system according to any one of claims 1 to 7.

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