Filter device and endoscope system

Abstract

To provide an inexpensive and compact filter device 30 in which ghost is reduced.SOLUTION: A filter device (30) comprises a filter (31) for attenuating light of a predetermined wavelength from light emitted from a cover glass (13) of an eyepiece (12) of an endoscope (10) along an optical axis (O), a frame (32) for holding the filter (31), and a connecting member (33) for mounting the frame (32) to a camera head (20) which holds the frame (32) and has an imaging element (21) for receiving light having passed through the filter (31), wherein the connecting member (33) includes an elastic region (33 er) for pressing the filter (31) or the frame (32) to the outer periphery of an effective optical path (EA) of the cover glass (13) or the periphery of the cover glass (13) when the camera head (20) is mounted on the eyepiece (12).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a filter device disposed between an eyepiece and a camera head of an endoscope, and to an endoscope system having a filter device disposed between the eyepiece and a camera head of an endoscope. [Background technology]

[0002] International Publication No. 2016 / 057483 discloses a camera head that is detachably attached to an eyepiece of an endoscope that acquires an image of a subject, and captures the image of the subject emitted from the eyepiece.

[0003] A filter device for blocking or attenuating laser wavelength light from the light emitted from an endoscope used in laser surgery is disposed between the eyepiece and camera head of the endoscope.

[0004] Furthermore, in endoscopes that perform fluorescence observation, in which excitation light is irradiated and fluorescence from a lesion site is detected, a filter device for blocking or attenuating the excitation light is also indispensable.

[0005] However, if the filter of the filter device is not arranged parallel to the cover glass that constitutes the light exit surface of the eyepiece, reflected light occurs between the cover glass and the filter, resulting in so-called ghosts.

[0006] To reduce ghosting, it is effective to provide an anti-reflection coating on the cover glass and the filter, but providing an anti-reflection coating increases costs.

[0007] Japanese Patent Application Laid-Open Publication No. 2021-129625 discloses a camera head in which a pressing portion of an elastic portion presses an optical element made of a light-transmitting material such as sapphire glass, and fixes the optical element in a tilted state with respect to the optical axis. This camera head does not take into consideration reducing ghosts caused by reflected light. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2016 / 057483 [Patent Document 2] Patent Publication No. 2021-129625 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide an inexpensive, small-sized filter device with reduced ghosts, and an endoscope system including the inexpensive, small-sized filter device with reduced ghosts. [Means for solving the problem]

[0010] The filter device of the embodiment comprises a filter that attenuates light of a predetermined wavelength from light emitted along an optical axis from a cover glass of an eyepiece of an endoscope, a frame that holds the filter, and a connecting member that holds the frame and attaches the frame to a camera head that has an image sensor that receives transmitted light that has passed through the filter, and the connecting member includes an elastic region that presses the filter or the frame against the outer periphery of the effective optical path of the cover glass or against the periphery of the cover glass when the camera head is attached to the eyepiece.

[0011] An endoscopic system according to an embodiment comprises an endoscope that emits light along an optical axis from a cover glass of an eyepiece, a camera head that is attached to the eyepiece and has an image sensor that converts the emitted light into an electrical signal, and a filter device disposed between the eyepiece and the camera head, the filter device having a filter that attenuates light of a predetermined wavelength from the emitted light, a frame that holds the filter, and a connecting member that holds the frame and attaches the frame to the camera head, the connecting member including an elastic region that presses the filter or the frame against the outer periphery of the effective optical path of the cover glass or against the periphery of the cover glass when the camera head is attached to the eyepiece. [Effects of the Invention]

[0012] According to the embodiment, it is possible to provide an inexpensive, compact filter device with reduced ghosting, and an endoscope system including an inexpensive, compact filter device with reduced ghosting. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a configuration diagram of an endoscope system according to an embodiment. [Figure 2] FIG. 2 is a partial cross-sectional view of an endoscope system in which a camera head is not attached to the eyepiece of the endoscope. [Figure 3] FIG. 3 is a perspective view of the front surface of the filter device according to the embodiment. [Figure 4] FIG. 4 is a perspective view of the rear surface of the filter device according to the embodiment. [Figure 5] FIG. 5 is a partial cross-sectional view of an endoscope system in which a camera head is attached to the eyepiece of an endoscope. [Figure 6] FIG. 6 is a partially enlarged view of FIG. [Figure 7] FIG. 7 is a perspective view of the front surface of the filter device according to the first modification of the embodiment. [Figure 8] FIG. 8 is a perspective view of the front surface of a filter device according to a second modification of the embodiment. [Figure 9] FIG. 9 is a partial cross-sectional view of an endoscope system having a filter device according to the first modification. [Figure 10] FIG. 10 is a partial cross-sectional view of an endoscope system having a filter device according to the second modification. [Figure 11] FIG. 11 is a partial cross-sectional view of an endoscope system having a filter device according to the third modification. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments will be described with reference to the drawings. The drawings of the embodiments are schematic. The relationship between the thickness and width of each part in the drawings, the thickness ratio of each part, etc., differ from the actual ones. The drawings also include parts with different dimensional relationships and ratios. Some components will not be shown or labeled.

[0015] <Configuration of endoscope system> 1, an endoscope system 1 of the embodiment includes an endoscope 10, a camera head 20, a filter device 30, a light source device 40, a control device 50, and a display device 60. The endoscope 10 and the light source device 40 are connected by an optical cable 41 that guides illumination light. The camera head 20, the light source device 40, and the display device 60 are connected to the control device 50 by transmission cables 51, 52, and 53.

[0016] The endoscope 10 is a so-called rigid endoscope having an insertion section 11 and an eyepiece section 12. The endoscope 10 has the insertion section 11 which is either entirely rigid or partially flexible and partially rigid. The insertion section 11 is inserted into a living body. The insertion section 11 is provided with an optical system having multiple lenses that focuses an image of a subject.

[0017] The eyepiece 12 is provided at the base end of the insertion section 11. The eyepiece 12 is provided with an optical system that emits an object image focused by the optical system of the insertion section 11 from the eyepiece 12 to the outside.

[0018] The light source device 40 generates light for illuminating the inside of a living body. The light source device 40 is separate from the control device 50, but may be provided inside the control device 50. The light supplied to the endoscope 10 is emitted from the tip of the insertion section 11 and irradiated into the living body. The light (subject image) irradiated into the living body and reflected inside the living body is collected by an optical system in the insertion section 11.

[0019] An imaging element 21 is disposed in the camera head 20. The camera head 20 is detachably attached to the eyepiece 12 of the endoscope 10. The imaging element 21 converts light emitted from the eyepiece 12 of the endoscope 10 along the optical axis O into an electrical signal.

[0020] The housing of the eyepiece 12 and the housing of the camera head 20 are made of metal such as aluminum alloy or hard resin such as epoxy resin.

[0021] The display device 60 is a display using a liquid crystal display or the like, and displays an observation image based on a video signal from the control device 50 .

[0022] The control device 50 includes a CPU (Central Processing Unit) and the like, and controls the entire endoscope system 1.

[0023] As shown in FIG. 2, a cover glass 13 is disposed at the proximal opening of the eyepiece 12 of the endoscope 10. The filter device 30 is attached to the housing of the camera head 20. The filter device 30 has a filter 31, a frame 32 that holds the filter 31, and a connecting member 33 that holds the frame 32. The connecting member 33 attaches the frame 32 to the camera head 20, which has an image sensor 21 that receives transmitted light that has passed through the filter 31.

[0024] The endoscope system 1 performs fluorescent observation of cancer cells. Specifically, the system utilizes the fact that cancer cells specifically take up 5-aminolevulinic acid and biosynthesize PpIX (protoporphyrin IX), which emits fluorescence. Specifically, PpIX emits red fluorescence at 380 nm when irradiated with blue excitation light at a wavelength of 380 nm.

[0025] The filter 31 is a so-called bandpass filter that blocks most of the excitation light with a wavelength of 380 nm from the light emitted from the cover glass 13 of the eyepiece 12 of the endoscope 10, but passes most of the light other than the excitation light, including fluorescence with a wavelength of 380 nm. Therefore, the endoscope system 1 can display high-quality images on the display device 60 during endoscopic surgery, with the influence of the excitation light reduced.

[0026] It is preferable that the filter 31 attenuates the excitation light by at least 70% or more, and particularly preferably by 99.9% or more.

[0027] When the endoscope system 1 performs laser surgery, the filter 31 blocks laser light with a wavelength of 532 nm, which is effective in vaporizing, excising, and cutting tissue, or laser light with a wavelength of 1064 nm, which enhances the coagulation effect.

[0028] When attaching the camera head 20 to the endoscope 10 (eyepiece 12), the eyepiece 12 is fitted to the camera head 20 and then rotated to fix the camera head 20. When attaching the filter device 30 to the camera head 20, the fitting portion 35 extending from the outer periphery of the connecting member 33 of the filter device 30 is fitted to the camera head 20 and then rotated to fix the filter device 30.

[0029] 3, the filter device 30 has three protrusions 36 that protrude in the optical axis direction on a substantially circular frame 32 that holds the filter 31. The three protrusions 36 are arranged at positions that are rotationally symmetrical about the optical axis O. The heights of the three protrusions 36, i.e., the dimensions in the optical axis direction, are the same.

[0030] The connecting member 33 of the filter device 30 is made of a hard material, but has a plurality of slits SL arranged rotationally symmetrically around the optical axis O. Therefore, the outer peripheral region of the connecting member 33 forms an elastic region 33ER that elastically deforms in the optical axis direction. The elastic region 33ER may be made thin or made of a soft material.

[0031] The endoscope 10 (eyepiece 12) and the camera head 20, and the camera head 20 and the filter device 30 are each detachably attached. For this reason, the filter 31 is not necessarily arranged parallel to the cover glass 13. As already explained, if the filter 31 is not arranged parallel to the cover glass 13, ghosts will occur.

[0032] As shown in FIGS. 5 and 6, when the camera head 20 is attached to the eyepiece 12, the elastic region 33ER of the connecting member 33 presses the three protrusions 36 of the frame 32 against the outer periphery of the effective optical path EA of the cover glass 13.

[0033] That is, as shown in FIG. 6, when the camera head 20 is attached to the eyepiece 12, the elastic region 33ER is deformed, and the frame 32 (filter 31) moves in the direction of the imaging element 21, compared to when the camera head 20 is not attached to the eyepiece 12.

[0034] The distance between the filter 31 and the cover glass 13 is determined by the height of the protrusions 36, and the parallelism between the filter 31 and the cover glass 13 is ensured by the three protrusions 36 arranged on the circumference.

[0035] In other words, the connecting member 33 has a first member 33A which is a fitting portion 35 parallel to the optical axis O for attaching the frame 32 to the housing of the camera head 20, and a second member 33B which is an elastic region 33ER connected to the first member 33A and perpendicular to the optical axis O, and when the camera head 20 is attached to the eyepiece portion 12, the angle θ formed between the first member 33A and the second member 33B changes from a right angle to an acute angle, as shown in Figure 6.

[0036] In the filter device 30, the filter 31 is arranged reliably parallel to the cover glass 13, so that no ghosts occur.

[0037] The filter device 30 is inexpensive because it does not require anti-reflection coating. When the camera head 20 is attached to the eyepiece 12, the angle θ between the first member 33A and the second member 33B changes from a right angle to an acute angle, thereby shortening the dimension in the optical axis direction of the filter device 30.

[0038] In order to ensure that the filter 31 is arranged parallel to the cover glass 13, it is preferable that the number of protrusions 36 is three or more.

[0039] <Modification> The filter devices 30A-30E of the modified examples are similar to the filter device 30 of the embodiment and have the same effects. Therefore, in the following description, components having the same functions as those of the filter device 30 are given the same reference numerals as those of the filter device 30, and descriptions thereof will be omitted.

[0040] <Variation 1> In a filter device 30A of this modification shown in FIG. 7, a frame 32 has a plurality of arc-shaped protrusions 36A of the same height that are arranged rotationally symmetrically in the optical axis direction.

[0041] If the frame 32 has two or more arc-shaped protrusions 36A arranged symmetrically with respect to the optical axis O, the filter 31 can be arranged in parallel with the cover glass 13 with reliability.

[0042] <Variation 2> The frame 32 of the filter device 30B of this modified example shown in FIG. 8 has an annular protrusion 36B that has a uniform height in the optical axis direction and surrounds the effective optical path EA of the cover glass 13.

[0043] If the frame 32 has one annular protrusion 36B, the filter 31 can be reliably arranged parallel to the cover glass 13.

[0044] <Variation 3> In the modified filter device 30C shown in FIG. 9, when the camera head 20 is attached to the eyepiece 12, the elastic region 33ER presses the filter 31 against the outer periphery of the effective optical path EA of the cover glass 13.

[0045] <Variation 4> 10, the elastic region 33ER presses the protrusion 36 of the filter device 30D of this modification against the periphery of the cover glass 13 when the camera head 20 is attached to the eyepiece 12. The protrusion 36 has the same configuration as in the embodiment or modifications 1 and 2.

[0046] <Variation 5> 11, when the camera head 20 is attached to the eyepiece 12, at least one protrusion 14 protruding in the optical axis direction of the eyepiece 12 abuts against the outer periphery of the effective optical path EA of the filter 31. The effective optical path EA of the filter 31 and the effective optical path EA of the cover glass 13 are approximately the same size. The protrusion 14 has the same configuration as the protrusion 36 in the embodiment or modifications 1 and 2.

[0047] The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0048] 10. Endoscope 11 Insertion section 12...Eyepiece 13. Cover glass 14...Convex 20. Camera head 21. Image sensor 30, 30A-30E... Filter device 31···Filter 32...frame 33 Connection member 33ER Elastic region 35. Fitting part 36, 36A, 36B...Convex 40...Light source device 41 Optical fiber cable 50...Control device 51, 52 Transmission cable 60...Display device

Claims

1. a filter for attenuating light of a predetermined wavelength from light emitted along an optical axis from a cover glass of an eyepiece of the endoscope; a frame for holding the filter; a connecting member for holding the frame and attaching the frame to a camera head having an image pickup element for receiving light that has passed through the filter; A filter device characterized in that the connecting member includes an elastic region that presses the filter or the frame against the outer periphery of the effective optical path of the cover glass or against the periphery of the cover glass when the camera head is attached to the eyepiece.

2. 2. The filter device according to claim 1, wherein the frame has at least one protrusion that protrudes in the optical axis direction.

3. 3. The filter device according to claim 2, wherein the convex portion abuts against the outer periphery of the effective optical path of the cover glass.

4. 3. The filter device according to claim 2, wherein the frame has three or more protrusions of the same height that are arranged rotationally symmetrically in the optical axis direction.

5. 3. The filter device according to claim 2, wherein the frame has a plurality of arc-shaped protrusions of the same height that are arranged rotationally symmetrically in the optical axis direction.

6. 3. The filter device according to claim 2, wherein the frame has an annular protrusion that has a uniform height in the optical axis direction and surrounds the effective optical path.

7. the elastic region has a plurality of slits arranged rotationally symmetrically around the optical axis, 2. The filter device according to claim 1, wherein the frame and the connecting member are made of a hard material.

8. The filter device according to claim 1, wherein the frame moves in a direction toward the imaging element when the camera head is attached to the eyepiece, compared to when the camera head is not attached to the eyepiece.

9. the connecting member includes a first member parallel to the optical axis for mounting the frame on the camera head, and a second member connected to the first member, perpendicular to the optical axis, and for holding the filter; 2. The filter device according to claim 1, wherein the second member forms an acute angle with respect to the first member when the camera head is attached to the eyepiece.

10. 2. The filter device according to claim 1, wherein at least one projection of the eyepiece portion that projects in the optical axis direction abuts against the outer periphery of the effective optical path of the filter.

11. an endoscope that emits light along an optical axis from a cover glass of an eyepiece; a camera head attached to the eyepiece and having an image sensor that converts the emitted light into an electrical signal; a filter device disposed between the eyepiece and the camera head; The filter device comprises: a filter that attenuates light of a predetermined wavelength from the emitted light; a frame for holding the filter; a connecting member for holding the frame and for attaching the frame to the camera head; an endoscope system characterized in that the connecting member includes an elastic region that presses the filter or the frame against the outer periphery of the effective optical path of the cover glass or against the periphery of the cover glass when the camera head is attached to the eyepiece.

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