Microdrape

Abstract

Provided is a microdrape configured so that attachment of the microdrape to a surgical microscope is facilitated. This microdrape comprises: a lens cap unit that is attached to or detached from a housing of an objective lens of a surgical microscope; a protective lens that protects the objective lens; and a drape body that covers the surgical microscope. The lens cap unit is provided with: a cylinder-shaped tubular body having an inner diameter dimension larger than that of the housing; a plurality of protrusions protruding, radially inward from the inner peripheral surface of the tubular body, at separate positions in a circumferential direction of the tubular body; and a biasing member for biasing a protrusion, from among the protrusions, which is supported so as to be retractable from the tubular body, in a direction protruding from the inner peripheral surface of the tubular body. The protective lens is supported by the distal end of the tubular body in a state of being inclined relative to the optical axis of the objective lens.

Description

Microdrape

[0001] The present invention relates to a microdrape for covering a surgical microscope.

[0002] In neurosurgery, otolaryngology, orthopedics, and ophthalmology, surgical procedures are sometimes performed using surgical microscopes to enlarge the surgical field. Although surgical procedures must be performed using sterile techniques, it is difficult to sterilize the surgical microscope itself. Therefore, it is common to cover the surgical microscope with a disposable microdrape after each surgery to ensure a clean field (see, for example, Patent Documents 1 to 4).

[0003] A typical microdrape is composed of a lens cap unit that is detachably attached to the objective lens of a surgical microscope and a bag-like drape body that is attached to the lens cap unit and covers the surgical microscope. Patent Document 5 also discloses various variations of lens cap units that can be attached to objective lenses of different diameters, and a configuration that changes the angle of the protective lens relative to the optical axis to prevent reflection and glare of incident light on the surgical microscope.

[0004] Japanese Patent Application Laid-Open No. 2012-183449 Japanese Patent Application Laid-Open No. 2014-161504 Japanese Patent Application Laid-Open No. 2010-512851 Japanese Patent Application Laid-Open No. 2017-107210 International Publication No. 2022 / 003806

[0005] However, the microdrape of Patent Document 5 has the problem that the process of attaching the lens cap unit to the objective lens is complicated (for example, the attachment procedure is significantly different from that of general microdrapes, and the attachment process requires a great deal of force).

[0006] The present invention has been made to solve the problems of the prior art, and its object is to provide a microdrape that is easier to attach to a surgical microscope.

[0007] In order to solve the above-mentioned problems, the present invention provides a microdrape comprising a lens cap unit that is detachably attached to a housing of an objective lens of a surgical microscope, a protective lens that protects the objective lens, and a drape main body that covers the surgical microscope, wherein the lens cap unit comprises a cylindrical body having an inner diameter dimension larger than the housing, a plurality of protrusions that protrude radially inward from the inner surface of the body at positions spaced apart circumferentially of the body, and a biasing member that biases the protrusions, among the plurality of protrusions, that are supported on the body so that they can be retracted, in a direction that causes them to protrude from the inner surface of the body, and the protective lens is supported at an angle to the optical axis of the objective lens at the tip of the body.

[0008] According to the present invention, a microdrape can be obtained that is easier to attach to a surgical microscope.

[0009] 1 is a schematic diagram of a main part of a surgical microscope and a microdrape. FIG. 1 is a perspective view of a microdrape according to a first embodiment, as seen from diagonally above. FIG. 2 is a perspective view of a microdrape according to a first embodiment, as seen from diagonally below. FIG. 3 is a longitudinal sectional view of a microdrape according to a first embodiment. FIG. 4 is a plan view of a microdrape according to a first embodiment. FIG. 5 is a longitudinal sectional view showing a state before a lens cap unit according to a first embodiment is attached to a housing. FIG. 6 is a longitudinal sectional view showing a state during attachment of a lens cap unit according to a first embodiment to a housing. FIG. 7 is a longitudinal sectional view showing a state after a lens cap unit according to a first embodiment has been attached to a housing. FIG. 8 is a plan view showing a state before a lens cap unit according to a first embodiment is attached to a housing. FIG. 9 is a plan view showing a state after a lens cap unit according to a first embodiment has been attached to a housing. FIG. 10 is an exploded perspective view of a lens cap unit according to a second embodiment, as seen from diagonally above. FIG. 11 is an exploded perspective view of a lens cap unit according to a second embodiment, as seen from diagonally below. FIG. 12 is an assembled perspective view of a lens cap unit according to a second embodiment, as seen from diagonally above. FIG. 13 is an assembled perspective view of a lens cap unit according to a second embodiment, as seen from diagonally below. FIG. 14 is a longitudinal sectional view showing a state before a lens cap unit according to a second embodiment is attached to a housing. FIG. 15 is a longitudinal sectional view showing a state after a lens cap unit according to a second embodiment has been attached to a housing. 10A and 10B are plan views showing a state before and after the lens cap unit according to the second embodiment is attached to the housing, respectively.

[0010] A microdrape 10 according to an embodiment will be described below with reference to the drawings. Note that the embodiment of the present invention described below is merely an example of how the present invention can be realized, and the scope of the present invention is not limited to the scope of the described embodiment. Therefore, the present invention can be implemented by adding various modifications to the embodiment.

[0011] Figure 1 is a schematic diagram of the main components of a surgical microscope 1 and a microdrape 10. As shown in Figure 1, the surgical microscope 1 mainly comprises multiple arms 2, 3, 4, and 5 rotatably connected to one another, and an objective lens 6 and an eyepiece 7 attached to the tip of arm 5. The joints of arms 2 to 5 rotate relative to one another, allowing the objective lens 6 to be positioned facing the surgical field. The doctor (operator) can then view the magnified surgical field by looking through the eyepiece 7.

[0012] The objective lens 6 is a convex lens and is attached to the inside of a cylindrical housing 8. That is, the optical axis L0 of the objective lens 6, indicated by the dashed line in FIG. 1, coincides with the axial direction of the housing 8.

[0013] Furthermore, the surgical microscope 1 is equipped with an illumination device (e.g., an LED or a xenon lamp). Light emitted from the illumination device passes through an optical system (lenses, mirrors, etc.) housed in the arms 2 to 5, passes through the objective lens 6, and is then emitted toward the surgical field. This light is reflected from the surgical field and enters the objective lens 6 again, allowing the surgeon to observe the surgical field. The direction of light emitted by the illumination device is tilted, for example, by approximately 3 to 6 degrees with respect to the optical axis L0.

[0014] All instruments that touch or may touch the surgical site during surgery must be sterilized. However, since it is difficult to sterilize the surgical microscope 1 itself, the surgical microscope 1 is covered with a disposable microdrape 10 after each surgery. The microdrape 10 is packaged in a sterilized state, and is unpacked in the operating room and placed over the surgical microscope 1.

[0015] First Embodiment As shown in FIG. 1, a microdrape 10 according to a first embodiment mainly includes a drape body 20 and a lens cap unit 30.

[0016] The drape body 20 is a sheet-like member made of a transparent or translucent material (e.g., polyethylene). The drape body 20 may have any known shape as long as it can cover the main portion of the surgical microscope 1. As one example, the drape body 20 may be a simple sheet or bag-like member. As another example, the drape body 20 may include a first drape and a second drape that are long and strip-like, as shown in Japanese Patent No. 6749532. As yet another example, the drape body 20 may include a bag-like portion and a strip-like portion, as shown in Japanese Patent No. 7122054.

[0017] The lens cap unit 30 is attached to the drape main body 20. More specifically, the microdrape 10 is integrated with the drape main body 20 by welding the lens cap unit 30 to the periphery of a through-hole 21 that penetrates the drape main body 20 in the thickness direction. The lens cap unit 30 is also attached to the housing 8. Furthermore, the lens cap unit 30 prevents reflection and glare of light incident on the surgical microscope 1.

[0018] [Configuration of Lens Cap Unit 30] Fig. 2A is a perspective view of the microdrape 10 according to the first embodiment as seen obliquely from above. Fig. 2B is a perspective view of the microdrape 10 according to the first embodiment as seen obliquely from below. Fig. 3A is a longitudinal cross-sectional view of the microdrape 10 according to the first embodiment. Fig. 3B is a plan view of the microdrape 10 according to the first embodiment.

[0019] As shown in Figures 2A to 3B, the lens cap unit 30 mainly includes a cap body 31, multiple (three in this embodiment) protrusions 32, 33, and 34, a coil spring 35 (an example of a biasing member), and a protective lens 36.

[0020] The cap body 31 supports the protrusions 32 to 34, the coil spring 35, and the protective lens 36, and is attached to the housing 8. The cap body 31 is made of, for example, a resin (for example, polypropylene). The cap body 31 is formed, for example, integrally with a cylindrical body 37 and a storage portion 38.

[0021] The cylinder 37 has a cylindrical outer shape with both axial ends open. The inner diameter of the cylinder 37 is set larger than the outer dimensions of various housings 8 intended for mounting the lens cap unit 30. The outer peripheral surface of the cylinder 37 is welded to the periphery of the through-hole 21 of the drape main body 20. As shown in FIG. 3A , the cylinder 37 according to the first embodiment has different axial lengths in the circumferential direction of the cylinder 37. More specifically, one axial end (the upper end in FIG. 3A ) of the cylinder 37 is perpendicular to the axial direction of the cylinder 37 indicated by the dashed line in FIG. 3A . Meanwhile, the other axial end (the lower end in FIG. 3A ) of the cylinder 37 is inclined with respect to the axial direction of the cylinder 37.

[0022] The accommodation portion 38 is a portion that protrudes from the outer peripheral surface of the cylindrical body 37 at a portion in the circumferential direction of the cylindrical body 37. The accommodation portion 38 according to the first embodiment is formed in the portion of the cylindrical body 37 that has the longest axial length in the circumferential direction. The accommodation portion 38 has an internal space that accommodates the coil spring 35. The cylindrical body 37 is formed with a through-hole 37a that penetrates the cylindrical body 37 in the thickness direction. The internal space of the cylindrical body 37 and the internal space of the accommodation portion 38 are in communication with each other via the through-hole 37a.

[0023] The protrusions 32 to 34 are formed of, for example, resin (e.g., polyurethane). The protrusions 32 to 34 are arranged at positions spaced apart in the circumferential direction of the cylindrical body 37. The protrusions 32 to 34 protrude radially inward from the inner circumferential surface of the cylindrical body 37. Of the protrusions 32 to 34, the protrusion 32 is a "movable protrusion 32," and the remaining two protrusions 33 and 34 are "fixed protrusions 33 and 34." The number of protrusions 32 to 34 is not limited to three, as long as it is two or more. The number of movable protrusions 32 is not limited to one, as long as it is one or more. In other words, all of the protrusions 32 to 34 may be movable protrusions 32 to 34.

[0024] The movable protrusion 32 is disposed at the position of the through-hole 37a. The movable protrusion 32 is supported in a manner that allows it to appear and disappear (protrude and retract) in the cylindrical body 37. Note that "the movable protrusion 32 retracts into the cylindrical body 37" does not require that the tip of the movable protrusion 32 is completely retracted into the cylindrical body 37; it is sufficient that the amount of protrusion of the movable protrusion 32 is reduced from the state in which the movable protrusion 32 protrudes most from the cylindrical body 37. Furthermore, the movable protrusion 32 is biased by the coil spring 35 in a direction that causes it to protrude from the inner circumferential surface of the cylindrical body 37. When the movable protrusion 32 protrudes most, the protrusions 32 to 34 may protrude the same amount from the inner circumferential surface of the cylindrical body 37.

[0025] The fixed protrusions 33, 34 are fixed in a state in which they protrude radially inward from the inner peripheral surface of the cylindrical body 37. Furthermore, in the circumferential direction of the cylindrical body 37, the distance L1 between the movable protrusion 32 and the fixed protrusion 33 is the same as the distance L1 between the movable protrusion 32 and the fixed protrusion 34. On the other hand, in the circumferential direction of the cylindrical body 37, the distance L2 between the fixed protrusions 33, 34 is narrower than the distance L1 between the movable protrusion 32 and the fixed protrusions 33, 34. However, the distances between the three protrusions 32 to 34 may be the same (120° in the case of the first embodiment).

[0026] The protective lens 36 is a flat lens made of a light-transmitting material (e.g., glass, polycarbonate, etc.). However, the shape of the protective lens 36 is not limited to a flat plate, and it may be a curved lens that protrudes into a convex shape. The protective lens 36 is fixed to the other axial end of the cylindrical body 37 (the end that is inclined with respect to the axial direction of the cylindrical body 37). The protective lens 36 is supported at the tip of the cylindrical body 37 in a state inclined with respect to the optical axis L0 of the objective lens 6. In other words, of both axial end portions of the cylindrical body 37, one end is open, and the other end is closed by the protective lens 36.

[0027] The protective lens 36 protects the objective lens 6 of the surgical microscope 1. More specifically, when the lens cap unit 30 is attached to the housing 8, the protective lens 36 faces the objective lens 6 on the optical axis L0 of the objective lens 6. External light that passes through the protective lens 36 is incident on the objective lens 6. Furthermore, the protective lens 36 is tilted with respect to the optical axis L0 to prevent reflection and glare of light incident on the surgical microscope 1.

[0028] [Method of attaching the lens cap unit 30] Fig. 4 is a vertical cross-sectional view showing the lens cap unit 30 according to the first embodiment before (A), during (B), and after (C) attachment to the housing 8. Fig. 5 is a plan view showing the lens cap unit 30 according to the first embodiment before (A) and after (B) attachment to the housing 8.

[0029] First, as shown in Fig. 4A, the lens cap unit 30 is placed below the housing 8 so that the open end of the cylindrical body 37 faces the underside of the housing 8 (i.e., the open end of the cylindrical body 37 faces upward). At this time, the movable protrusion 32 is in its most protruding state, as shown in Figs. 4A and 5A.

[0030] 4B , the cylindrical body 37 is tilted so that the side on which the movable protrusion 32 is provided faces up, and the movable protrusion 32 is pressed against the side surface of the housing 8, causing the movable protrusion 32 to retract into the cylindrical body 37 (in other words, the amount of protrusion of the movable protrusion 32 is reduced) against the biasing force of the coil spring 35. Meanwhile, at this point, the fixed protrusions 33 and 34 are not in contact with the side surface of the housing 8.

[0031] 4C , while maintaining the retracted state of the movable protrusion 32, the inclination of the cylindrical body 37 is returned to its original position. This causes the cylindrical body 37 to be inserted into the housing 8. Then, by reducing the force in the direction of retracting the movable protrusion 32, the amount of protrusion of the movable protrusion 32 increases, and the tips of the fixed protrusions 33 and 34 come into contact with the side surfaces of the housing 8. This causes the lens cap unit 30 to be attached to the housing 8. The amount of protrusion of the movable protrusion 32 at this time varies depending on the diameter of the housing 8.

[0032] Here, an imaginary circle connecting the tips of the protrusions 32 to 34 when the movable protrusion 32 is at its most protruding (the dashed-dotted line in FIG. 5A ) and an imaginary circle connecting the tips of the protrusions 32 to 34 when the amount of protrusion of the movable protrusion 32 is reduced (the dashed-two-dotted line in FIG. 5B ) slide by the amount of protrusion of the movable protrusion 32. Furthermore, the diameter D2 of the imaginary circle shown by the dashed-two-dotted line in FIG. 5B is larger than the diameter D1 of the imaginary circle shown by the dashed-dotted line in FIG. 5A . In other words, by changing the amount of protrusion of the movable protrusion 32, the diameter of the imaginary circle connecting the tips of the protrusions 32 to 34 (i.e., the diameter of the housing 8) changes.

[0033] Next, although not shown, the drape body 20 is placed and fixed over the surgical microscope 1. This allows the surgical microscope 1 to be kept clean.

[0034] 4A to 5B , the lens cap unit 30 can be attached to the housing 8 by pressing the movable protrusion 32 against the side of the housing 8 and retracting it into the cylindrical body 37, and then inserting the cylindrical body 37 onto the housing 8. This simplifies the attachment process to the surgical microscope 1 compared to the various lens cap units exemplified in Patent Document 5. Furthermore, unlike the various lens cap units exemplified in Patent Document 5, there is no need for large elastic deformation when attaching the lens cap unit to the surgical microscope 1, and therefore the force required for attachment can be reduced.

[0035] Furthermore, according to the above embodiment, by providing three protrusions 32 to 34, the lens cap unit 30 can be attached more stably to the housing 8 than when two protrusions are provided. Furthermore, by providing the minimum number of protrusions, three, the configuration of the lens cap unit 30 can be simplified.

[0036] Furthermore, according to the above embodiment, by making the distance L2 between the fixed protrusions 33 and 34 narrower than the distance L1 between the movable protrusion 32 and the fixed protrusions 33 and 34, the housing 8 can be stably clamped between the movable protrusion 32 and the fixed protrusions 33 and 34.

[0037] Furthermore, by attaching a protective lens 36 to the tip of the cylindrical body 37 in a state inclined with respect to the optical axis L0 of the objective lens 6, it is possible to prevent reflection and glare of the light incident on the surgical microscope 1. As a result, it is possible to prevent the surgeon looking through the surgical microscope 1 from being hindered in surgery by reflection and glare.

[0038] Second Embodiment Fig. 6 is an exploded perspective view of a lens cap unit 40 according to a second embodiment, as seen obliquely from above. Fig. 7 is an exploded perspective view of a lens cap unit 40 according to the second embodiment, as seen obliquely from below. Fig. 8 is an assembled perspective view of the lens cap unit 40 according to the second embodiment. Fig. 9 is a vertical cross-sectional view of the lens cap unit 40 according to the second embodiment. Fig. 10 is a plan view of the lens cap unit 40 according to the second embodiment. Note that a detailed description of commonalities with the first embodiment will be omitted, and the following description will focus on differences. In addition, the same names are used for components having the same basic functions in the first and second embodiments.

[0039] As shown in Figures 6 to 10B, the lens cap unit 40 according to the second embodiment mainly comprises a cap main body 41, multiple (three in this embodiment) protrusions 42, 43, and 44, a spring body 45 (an example of a biasing member), and a protective lens unit 50.

[0040] The cap body 41 is, for example, a member made of resin (e.g., polypropylene) in which a base plate 46, a cylindrical body 47, and a storage portion 48 are integrally formed. The base plate 46 is a flat plate-shaped portion. The peripheral edge of the through-hole 21 of the drape body 20 is welded to the base plate 46. The base plate 46 also has a through-hole 46a that penetrates in the thickness direction. The cylindrical body 47 protrudes from the lower surface of the base plate 46 so as to surround the through-hole 46a. The storage portion 48 is formed on the lower surface of the base plate 46 so as to protrude from the outer circumferential surface of the cylindrical body 47.

[0041] The cylindrical body 47 according to the second embodiment differs from the cylindrical body 37 according to the first embodiment in the following respects. First, the other axial end of the cylindrical body 47 is perpendicular to the axial direction of the cylindrical body 47. Furthermore, the cylindrical body 47 is formed with through holes 47a, 47b, and 47c, a contact ring 47d (contact portion), a notch 47e, and a recessed groove 47f.

[0042] The through holes 47a to 47c penetrate the cylindrical body 47 in the thickness direction at positions spaced apart in the circumferential direction of the cylindrical body 47. The through holes 47a to 47c are provided closer to the base plate 46 than the abutment ring 47d in the axial direction of the cylindrical body 47. Protrusions 42 to 44, which will be described later, are inserted into the through holes 47a to 47c. In other words, the through hole 47a connects the internal space of the cylindrical body 47 with the internal space of the accommodation portion 48. The positions of the through holes 47b and 47c are the same as the layout of the protrusions 32 to 34 described in the first embodiment.

[0043] The abutment ring 47d protrudes radially inward from the inner circumferential surface of the cylindrical body 47. Furthermore, the abutment ring 47d according to this embodiment is continuous in the circumferential direction. However, the abutment ring 47d may be provided only on a portion of the inner circumferential surface of the cylindrical body 47 in the circumferential direction. The abutment ring 47d abuts against the tip of the housing 8 that is inserted into the cylindrical body 47 from the base plate 46 side, thereby controlling the insertion amount of the housing 8 into the cylindrical body 47.

[0044] The notch 47e is provided in a portion of the circumferential direction of the cylindrical body 47 (at the position where the accommodation portion 48 is provided) of the end portion on the other axial side (opposite the base plate 46) of the cylindrical body 47. In other words, the notch 47e is provided on the opposite side of the abutment ring 47d from the base plate 46. The notch 47e is a space that allows the lid portion 53 of the protection lens unit 50 to pass through.

[0045] The groove 47f is provided on the inner peripheral surface of the cylindrical body 47 on the opposite side of the abutment ring 47d from the base plate 46. The groove 47f is continuous in the circumferential direction of the cylindrical body 47. However, the groove 47f is divided at the position of the notch 47e. The groove 47f receives a protrusion 54 provided on the ring portion of the protection lens unit 50, thereby fixing the protection lens unit 50 to the cap body 41.

[0046] The accommodation portion 48 is a frame-shaped portion that defines a space for accommodating the spring body 45. One axial end of the accommodation portion 48 is closed by the base plate 46. Meanwhile, the other axial end of the accommodation portion 48 is configured to be openable and closable by a lid portion 53 of the protective lens unit 50. Furthermore, a pin 48a that protrudes from the underside of the base plate 46 is formed inside the accommodation portion 48.

[0047] The basic configuration and role of the protrusions 42 to 44 according to the second embodiment are the same as those of the protrusions 32 to 34 according to the first embodiment. Furthermore, the protrusion 42 is a "movable protrusion 42," and the protrusions 43 and 44 are "fixed protrusions 43 and 44." Furthermore, as shown in FIG. 9A, the protrusion 42 is composed of a neck portion 42a, a head portion 42b, and an abutment portion 42c. The configuration of the protrusions 43 and 44 is also the same, so the protrusion 42 will be described in detail below.

[0048] The neck portion 42a is the portion that passes through the connecting portion 45a of the spring body 45. The head portion 42b is formed at one end of the neck portion 42a. The head portion 42b has a larger opening area than the connecting portion 45a. The head portion 42b has a tapered shape that narrows toward the tip. The abutting portion 42c is formed at the other end of the neck portion 42a. The abutting portion 42c has a larger opening area than the connecting portion 45a. The abutting portion 42c abuts against the outer peripheral surface of the housing 8.

[0049] When the head 42b is press-fitted into the connecting portion 45a from the inner circumferential surface side of the cylindrical body 47, the tapered head 42b is elastically compressed and passes through the connecting portion 45a. Then, as shown in FIG. 9A , the neck 42a is positioned within the connecting portion 45a, and the abutting portion 42c protrudes inside the cylindrical body 47. Similarly, when the heads 43b, 44b are press-fitted into the through holes 47b, 47c from the inner circumferential surface side of the cylindrical body 47, the tapered heads 43b, 44b are elastically compressed and pass through the through holes 47b, 47c. Then, the necks 43a, 44a are positioned within the through holes 47b, 47c, the heads 43b, 44b are positioned outside the cylindrical body 47, and the abutting portions 43c, 44c are positioned inside the cylindrical body 47.

[0050] The spring body 45 is another example of a biasing member that biases the movable protrusion 42 in a direction that protrudes from the inner circumferential surface of the cylindrical body 47. In other words, the biasing member is not limited to the coil spring 35 according to the first embodiment, and various shapes can be adopted. As shown in Figures 6 and 7, the spring body 45 is, for example, a member made of resin (e.g., polyacetal) in which a connecting portion 45a, a fixing portion 45b, and a pair of leaf springs 45c, 45d are integrally molded.

[0051] The connecting portion 45a has an opening to which the head 42b of the protrusion 42 is connected. The fixing portion 45b receives the pin 48a to fix the spring body 45 in the housing portion 48. The leaf springs 45c and 45d have one end connected to the connecting portion 45a and the other end connected to the fixing portion 45b, and are elastically compressed. By attaching the movable protrusion 42 to the connecting portion 45a and inserting the pin 48a into the fixing portion 45b, the movable protrusion 42 protrudes radially inward from the inner circumferential surface of the cylindrical body 47, as shown in FIGS. 8A and 10A .

[0052] The protective lens unit 50 is a member for fixing the protective lens 52 to the cap body 41 in a state inclined with respect to the optical axis L0. As shown in Figures 6 and 7, the protective lens unit 50 is a member made of resin (e.g., polycarbonate) in which, for example, a ring portion 51, a protective lens 52, and a lid portion 53 are integrally formed.

[0053] The ring portion 51 has a generally cylindrical outer shape. The ring portion 51 is inserted into the cylindrical body 47. That is, the outer diameter of the ring portion 51 is set to be the same as or slightly smaller than the inner diameter of the cylindrical body 47. Furthermore, a protrusion 54 is formed on the outer peripheral surface of the ring portion 51. The protrusion 54 protrudes radially outward from the outer peripheral surface of the ring portion 51 and extends in the circumferential direction of the ring portion 51. When the ring portion 51 is inserted into the cylindrical body 47, the protrusion 54 enters the recessed groove 47f, thereby fixing the protective lens unit 50 to the cap main body 41. However, the method of fixing the protective lens unit 50 to the cap main body 41 is not limited to this and may be adhesive, welding, fastening with bolts, or a combination of these.

[0054] The basic configuration and role of the protective lens 52 according to the second embodiment are the same as those of the protective lens 36 according to the first embodiment. The protective lens 52 is located inside the ring portion 51. More specifically, the protective lens 52 is disposed within the ring portion 51 so as to be inclined with respect to the optical axis L0 when the protective lens unit 50 is fixed to the cap body 41.

[0055] The lid portion 53 is a portion that protrudes radially outward from a portion of the circumference of the ring portion 51. The lid portion 53 closes the accommodation portion 48 when the ring portion 51 is inserted into the cylindrical body 47, thereby preventing the spring body 45 from falling off.

[0056] The second embodiment also provides the same effects as the first embodiment. Furthermore, according to the second embodiment, by inserting the cylindrical body 47 into the housing 8 until the tip of the housing 8 abuts against the abutment ring 47d, the objective lens 6 and the protective lens 52 are set at an appropriate distance. As a result, the work of attaching the microdrape 10 to the surgical microscope 1 becomes even easier.

[0057] DESCRIPTION OF SYMBOLS 1...surgical microscope, 2, 3, 4, 5...arm, 6...objective lens, 7...eyepiece lens, 8...housing, 10...microdrape, 20...drape body, 21, 37a, 46a, 47a, 47b, 47c...through-hole, 30, 40...lens cap unit, 31, 41...cap body, 32, 33, 34, 42, 43, 44...protrusion, 35...coil spring, 36, 52...protective lens, 37, 47...cylindrical body, 38, 48...accommodating section, 45...spring body, 46...base plate, 47d...abutment ring, 47e...notch, 47f...recess, 48a...pin, 50...protective lens unit, 51...ring portion, 53...lid portion, 54...rib

Claims

1. A microdrape comprising a lens cap unit detachably attached to a housing of an objective lens of a surgical microscope, a protective lens for protecting the objective lens, and a drape body for covering the surgical microscope, wherein the lens cap unit comprises: a cylindrical body having an inner diameter dimension larger than the housing, a plurality of protrusions each protruding radially inward from the inner surface of the body at positions spaced apart circumferentially of the body, and a biasing member for biasing one of the plurality of protrusions, which is supported on the body so as to be able to protrude and retract, in a direction such that it protrudes from the inner surface of the body, and the protective lens is supported on the tip of the body in a state inclined with respect to the optical axis of the objective lens.

2. A microdrape as described in claim 1, characterized in that the protrusions are provided at three locations spaced apart in the circumferential direction of the cylindrical body.

3. A microdrape as described in claim 2, wherein the three protrusions include one movable protrusion supported on the cylindrical body so as to be able to protrude and retract, and two fixed protrusions fixed in a state protruding from the inner surface of the cylindrical body, and the distance between the two fixed protrusions in the circumferential direction of the cylindrical body is narrower than the distance between the movable protrusion and the fixed protrusion.

4. A microdrape as described in claim 1, wherein the lens cap unit comprises a cap body integrally formed with the cylindrical body and a storage section that protrudes from the outer peripheral surface of the cylindrical body and stores the biasing member, the cylindrical body has a through hole formed therein that communicates with the storage section, and the protective lens unit further comprises a protective lens unit that fixes the protective lens to the cap body in a state inclined with respect to the optical axis, and the protective lens unit is integrally formed with a ring section that is inserted into the cylindrical body, the protective lens located inside the ring section, and a lid section that closes the storage section when the ring section is inserted into the cylindrical body.

5. A microdrape as described in claim 4, characterized in that a circumferentially extending groove is formed on the inner peripheral surface of the cylindrical body, and a circumferentially extending protrusion is formed on the outer peripheral surface of the ring portion, which protrudes into the groove.

6. The microdrape according to claim 4, wherein the cap body is made of polypropylene, and the protective lens unit is made of polycarbonate.

7. A microdrape as described in claim 1, wherein the lens cap unit has an abutment portion that protrudes radially inward from the inner peripheral surface of the cylindrical body and abuts against the tip of the housing.

Images