Sealing unit

Abstract

A sealing unit according to an embodiment of the present invention may comprise: an optical body including an incident surface on which a laser beam is incident and a pressing surface from which the laser beam is emitted and which presses an object; a laser unit for irradiating the incident surface with the laser beam; and a mirror cover covering the optical body, having an inner surface on which the laser beam is reflected, and having an opening through which the pressing surface is exposed.

Description

Sealing unit

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0185715 filed on December 13, 2024, and all contents disclosed in the document of said Korean Patent Application are incorporated herein as part of this specification.

[0003] Technology field

[0004] The present invention relates to a sealing unit for sealing a pouch-type outer material.

[0005] Recently, with rising energy prices due to the depletion of fossil fuels and growing concern over environmental pollution, the demand for eco-friendly alternative energy sources has become an indispensable factor for future life. Accordingly, research on various power generation technologies, such as nuclear, solar, wind, and tidal power, is continuing, and there is also significant interest in power storage devices designed to utilize this generated energy more efficiently.

[0006] In terms of battery shape, there is high demand for prismatic and pouch-type rechargeable batteries, which can be applied to products such as mobile phones due to their thin thickness; in terms of materials, there is high demand for lithium-ion batteries, such as lithium-ion polymer batteries, which possess advantages such as high energy density, discharge voltage, and output stability.

[0007] Secondary batteries are classified according to the shape of the casing into cylindrical and prismatic batteries, in which the electrode assembly is embedded in a cylindrical or prismatic metal can, and pouch-type batteries, in which the electrode assembly is embedded in a pouch-type casing made of an aluminum laminate sheet.

[0008] In particular, pouch-type secondary batteries, which utilize a flexible multilayer film as an outer packaging material, possess several advantages. Representative examples of these advantages include low manufacturing costs, light weight, and excellent heat dissipation performance, as well as the ability to ensure stability by opening before excessive internal pressure builds up.

[0009] Meanwhile, the outer material of a pouch-type secondary battery may include a sealing portion that is sealed by thermal fusion. Such a sealing portion is generally formed by applying pressure by a heated sealing tool of a sealing unit.

[0010] Conventional sealing units heated the sealing tool by heat conduction. More specifically, the conventional sealing unit included a main body equipped with a heater and a sealing tool attached to the main body. Heat generated from the heater was conducted to the sealing tool through the main body. In this case, there was a problem in that a large amount of heat was lost during the conduction process, resulting in low heat transfer efficiency and a long sealing time.

[0011] The problem that the present invention aims to solve is to provide a sealing unit capable of sealing an object quickly and with high quality through laser sealing.

[0012] A sealing unit according to an embodiment of the present invention may include: an optical body comprising an incident surface into which a laser beam is incident and a pressure surface into which a laser beam is emitted and which presses an object; a laser unit that irradiates a laser beam onto the incident surface; and a mirror cover that covers the optical body and has an opening formed therein that reflects the laser beam from its inner surface and exposes the pressure surface.

[0013] The inner surface of the above mirror cover may be provided with a reflective layer having a predetermined reflectivity so that a laser beam is reflected.

[0014] The laser unit may include a plurality of light sources arranged to face the incident surface.

[0015] The above laser unit may be a VCSEL (vertical-cavity surface-emitting laser) module.

[0016] The above-mentioned pressure surface is formed elongated in one direction, and the area of ​​the above-mentioned pressure surface may be narrower than the area of ​​the above-mentioned incident surface.

[0017] The optical body is provided with a protrusion that is inserted into the opening, and the outermost surface of the protrusion can define the pressure surface.

[0018] The above incident surface and pressure surface can be formed parallel to each other.

[0019] The optical body may further include a pair of first surfaces whose distance from each other decreases as they approach the pressure surface.

[0020] The above pair of first surfaces may be inclined planes or convex curved surfaces.

[0021] The above pair of first surfaces may face the incident surface with respect to the pressure direction of the pressure surface.

[0022] The above mirror cover may include a pair of first cover portions that cover the pair of first surfaces and have a distance between them that decreases as they approach the opening.

[0023] The optical body may further include a pair of second surfaces perpendicular to the incident surface, connecting the pair of first surfaces and the incident surface.

[0024] The above mirror cover may include a pair of second cover portions that cover the pair of second surfaces and are connected to the first cover portion.

[0025] According to a preferred embodiment of the present invention, by directly heating the sealing portion using a laser beam, there is an advantage in that the sealing portion can be heated quickly and smoothly compared to a method of heating a sealing tool by heat conduction. This prevents defects in the sealing portion caused by a drop in sealing temperature and reduces the time required for the sealing process.

[0026] In addition, by having the mirror cover cover the optical body, the laser beam emitted from the optical body to parts other than the pressure surface is prevented from being exposed to the outside and can be reflected into the optical body. Therefore, the laser beam can be reflected multiple times within the optical body and concentrated toward the pressure surface. This allows the heating efficiency of the sealing part to be further increased.

[0027] In addition to this, the configurations according to the preferred embodiments of the present invention may include effects that are easily predictable by those skilled in the art.

[0028] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0029] Figure 1 is an assembly diagram of a pouch-type secondary battery.

[0030] FIG. 2 is a schematic diagram of a sealing device including a sealing unit according to one embodiment of the present invention.

[0031] Figure 3 is a cross-sectional view of the sealing unit shown in Figure 2.

[0032] Figure 4 is an exploded perspective view of the sealing unit shown in Figure 2.

[0033] FIG. 5 is an exploded perspective view of a sealing unit according to another embodiment of the present invention.

[0034] Hereinafter, preferred embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in various different forms and is not limited or restricted by the following embodiments.

[0035] In order to clearly explain the present invention, detailed descriptions of related prior art that are irrelevant to the explanation or that may unnecessarily obscure the essence of the invention have been omitted. Furthermore, when assigning reference numerals to the components of each drawing in this specification, identical or similar reference numerals are assigned to identical or similar components throughout the entire specification.

[0036] Furthermore, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0037] Each component of a secondary battery according to one embodiment of the present invention is schematically illustrated in the drawing, and the size or thickness of the lines of the components may be expressed somewhat exaggerated for ease of understanding.

[0038] Figure 1 is an assembly diagram of a pouch-type secondary battery.

[0039] A pouch-type secondary battery (100) may include an electrode assembly (110) and a pouch-type outer material (120) (hereinafter referred to as 'outer material').

[0040] The electrode assembly (110) may be formed by interposing a separator between alternately arranged positive and negative electrodes. That is, the electrode assembly (110) may include a plurality of electrodes and a separator interposed between the plurality of electrodes to insulate the plurality of electrodes from each other. The electrode assembly (110) may be accommodated in an outer casing (120), more specifically in a storage portion (121) to be described later.

[0041] The electrode assembly (110) may be a stack type, a jelly roll type, a stack and folding type, etc., and the type of electrode assembly (110) is not limited.

[0042] The electrode assembly (110) may include electrode tabs (111) connected to a positive electrode and a negative electrode, respectively, and the electrode tabs (111) may serve as a path through which electrons can move between the inside and outside of the electrode assembly (110). The electrode tabs (111) may include a positive electrode tab connected to a positive electrode and a negative electrode tab connected to a negative electrode. The positive electrode tab and the negative electrode tab may protrude from the electrode assembly (110) in different directions, but are not limited thereto and may be formed to protrude in various directions, such as protruding in parallel from one side in the same direction.

[0043] The electrode assembly (110) may be provided with an electrode lead (112). The electrode lead (112) can electrically connect the electrode assembly (110) to the outside.

[0044] More specifically, the electrode lead (111) can be connected to the electrode tab (111) of the electrode assembly (110) by spot welding or the like. Additionally, a portion of the electrode lead (111) can be surrounded by an insulating member (113). The insulating member (113) can be positioned to correspond to the first sealing portion (122) of the battery case (120) to be described later. Thus, the insulating member (113) can insulate the electrode lead (112) from the sealing portion (122) and maintain the sealing of the sealing portion (122). Generally, insulating tape that is easy to attach to the electrode lead (112) and has a relatively thin thickness is often used as the insulating member (113), but it is not limited to this.

[0045] One end of the electrode lead (112) is connected to the electrode tab (111), and the other end may protrude outside the outer casing (120). The electrode lead (112) may include a positive lead connected to the positive tab and a negative lead connected to the negative tab. Since the positive tab and the negative tab are each formed to protrude in various directions, the positive lead and the negative lead may also extend in various directions.

[0046] The exterior material (120) can be formed by molding a laminate sheet and can accommodate an electrode assembly (110) inside.

[0047] The exterior material (120) may include a first exterior material (120A) having a receiving portion (121) formed therein for receiving an electrode assembly (110), a second exterior material (120B) covering the receiving portion (121), and a sealing portion (122) in which the first exterior material (120A) and the second exterior material (120B) come into contact with each other and are sealed.

[0048] As illustrated in FIG. 1, the first exterior material (120A) and the second exterior material (120B) can be connected by a folding portion (124). In this case, the first exterior material (120A) and the second exterior material (120B) can be sealed by having the remaining three sides, excluding the side where the folding portion (124) is formed, come into contact with each other.

[0049] However, it is not limited to this, and the first exterior material (120A) and the second exterior material (120B) may be manufactured separately from each other. In this case, the first exterior material (120A) and the second exterior material (120B) may be sealed by having four sides in contact with each other.

[0050] In the first exterior material (120A), a receiving portion (121) may be formed by recessing it to a predetermined depth. The second exterior material (120B) may cover this receiving portion (121). The second exterior material (120B) may be formed flat.

[0051] However, it is not limited to this, and as illustrated in FIG. 1, a receiving portion (121) may also be formed in the second outer material (120B). In this case, the receiving portion (121) of the second outer material (120B) may cover the receiving portion (121) of the first outer material (120A). That is, both receiving portions (121) may form a single receiving space in which the electrode assembly (110) is received.

[0052] The sealing portion (122) may be located around the perimeter of the receiving portion (121). The sealing portion (122) may be heat-sealed so that the first outer material (120A) and the second outer material (120B) come into contact with each other. However, a portion of the sealing portion (122) may be heat-sealed with the insulating member (113).

[0053] FIG. 2 is a schematic diagram of a sealing device including a sealing unit according to an embodiment of the present invention, FIG. 3 is a cross-sectional view of the sealing unit shown in FIG. 2, and FIG. 4 is an exploded perspective view of the sealing unit shown in FIG. 2.

[0054] A sealing unit (200) according to an embodiment of the present invention can seal an object by applying pressure and irradiating a laser. The object may be an outer material (120) of a secondary battery (100), more specifically, a sealing portion (122) of the outer material (120).

[0055] A pair of sealing units (200) may be provided facing each other with the object, i.e., the sealing portion (122), in between. More specifically, the pressure surfaces (212) to be described later of the pair of sealing units (200) may face each other with the sealing portion (122) in between. That is, the sealing portion (122) may be compressed and sealed between the pressure surfaces (212) of the pair of sealing units (200).

[0056] However, it is not limited thereto, and although not shown in the drawing, a support plate (not shown) may be disposed on one side of the sealing portion (122), and the pressing surface (212) of the sealing unit (200) located on the other side of the sealing portion (122) may face the support plate. In this case, the sealing portion (122) may be compressed and sealed between the pressing surface (212) of the sealing unit (200) and the support plate.

[0057] Each sealing unit (200) may include an optical body (210), a laser unit (220), and a mirror cover (230).

[0058] The optical body (210) may be configured to be vertically movable. For example, a lifting mechanism including a motor, etc., may be connected to the optical body (210). Thus, the optical body (210) may move toward an object, i.e., a sealing part (122), or move away from the sealing part (122).

[0059] The optical body (210) may have a transparent material through which a laser beam can pass. For example, the optical body (210) may have a quartz material. Since the quartz material has sufficient rigidity while allowing the laser beam to pass through, it can strongly press the object.

[0060] The optical body (210) may include an incident surface (211) into which a laser beam is incident, and a pressing surface (212) into which the laser beam is emitted and which presses against a sealing portion (122) of an object, i.e., an exterior material (120). The incident surface (211) and the pressing surface (212) may be formed parallel to each other.

[0061] The optical body (210) can change the path of a laser beam incident on the incident surface (211) (e.g., refract) and guide it to the pressure surface (212).

[0062] The incident surface (211) may face the laser unit (220) to be described later. A laser beam irradiated from the laser unit (220) may be incident on the incident surface (211).

[0063] The incident surface (211) may be located on the opposite side of the object with the optical body (210) in between. For example, the incident surface (211) of the optical body (210) of the sealing unit (200) located on the lower side of the object may be the bottom surface of the optical body (210). Conversely, the incident surface (211) of the optical body (210) of the sealing unit (200) located on the upper side of the object may be the top surface of the optical body (210).

[0064] The pressure surface (212) can apply pressure to the sealing portion (122) of the object, i.e., the exterior material (120).

[0065] The pressure surface (212) may face the object. For example, the pressure surface (212) of the optical body (210) of the sealing unit (200) located below the object may be the upper surface of the optical body (210). Conversely, the pressure surface (212) of the optical body (210) of the sealing unit (200) located above the object may be the lower surface of the optical body (210).

[0066] The pressure surface (211) can be formed long in one direction. That is, the pressure surface (211) can be formed long in a direction parallel to the sealing portion (122) of the exterior material (120). Therefore, the pressure surface (211) can smoothly press the sealing portion (122) as a whole.

[0067] More specifically, the optical body (210) may be provided with a protrusion (210a) that protrudes toward the sealing portion (122) of the object, i.e., the exterior material (120), and the outermost surface of the protrusion (210a) may define a pressure surface (212). The protrusion (210a) may be formed long in a direction parallel to the sealing portion (122) of the exterior material (120). Due to this protrusion (210a), the pressure surface (212) can contact and press against the sealing portion (122) despite the mirror cover (230) to be described later.

[0068] A laser beam incident on the incident surface (211) can be emitted to the pressurizing surface (212). More specifically, when the pressurizing surface (212) presses the sealing portion (122), the laser beam is irradiated onto the sealing portion (122) and can heat the sealing portion (122). Thus, the sealing portion (122), heated by the laser beam, can be heat-fused by being pressed by the pressurizing surface (212).

[0069] Thus, the optical body (210) has the advantage of being able to heat the sealing part (122) quickly and smoothly by using a laser beam to directly heat the sealing part (122), compared to a method of heating the sealing tool by heat conduction. This prevents defects in the sealing part (122) caused by a decrease in sealing temperature.

[0070] The area of ​​the pressure surface (212) may be narrower than the area of ​​the incident surface (211). Therefore, a laser beam incident on the incident surface (211) with a large area can be concentrated on the pressure surface (212) and emitted at high power. As a result, the sealing portion (122) of the object, i.e., the exterior material (120), can be heated more quickly.

[0071] The laser unit (220) can irradiate a laser beam onto the incident surface (211) of the optical body (210). For example, the laser unit (220) may be a VCSEL (vertical-cavity surface-emitting laser) module. Since the VCSEL module operates similarly to a surface light source, it has the advantage of generating less heat and providing an appropriate laser beam output compared to a device that generally emits a laser.

[0072] The laser unit (200) may include a plurality of light sources (221) arranged to face the incident surface (211) of the optical body (210). Each light source (221) may be a laser diode. More specifically, the plurality of light sources (221) may be arranged in a predetermined matrix form. Thus, the laser unit (200) can irradiate a laser beam evenly across the incident surface (211).

[0073] A laser unit (220), more specifically a plurality of light sources (221), can come into contact with the incident surface (211) of the optical body (210). Thus, a laser beam irradiated from the laser unit (200) can enter the incident surface (211) intact without intermediate loss.

[0074] The laser unit (220) can be combined with the optical body (210). Thus, the laser unit (200) can move up and down together with the optical body (210). That is, the laser unit (220) can continuously irradiate a laser onto the incident surface (211) of the optical body (210) regardless of the movement of the optical body (210).

[0075] A reflective layer (not shown) may be provided on a portion of the surface of the laser unit (220) facing the incident surface (211) of the optical body (210). Accordingly, a laser beam reflected toward the incident surface (211) by the mirror cover (230) described later may be reflected from the reflective layer and re-incident upon the incident surface (211). Thus, the laser beam may be concentrated on the pressure surface (212) of the optical body (210).

[0076] The optical body (210) may further include a pair of first surfaces (213) such that the distance between them decreases as they approach the pressure surface (212). The pair of first surfaces (213) may be located on both sides with the protrusion (210a), i.e., the pressure surface (212), in between.

[0077] A pair of first surfaces (213) may face an incident surface (211) in a direction parallel to the pressure direction of the pressure surface (212). The distance between the incident surface (211) and the first surface (213) in the pressure direction of the pressure surface (212) may decrease as it moves further away from the pressure surface (212).

[0078] In the case of this embodiment, each first surface (213) may be a slanted plane.

[0079] A pair of first surfaces (213) may have a shape that is symmetric to each other. More specifically, a pair of first surfaces (213) may be symmetric to each other with respect to a virtual line that passes vertically through the center of the pressure surface (212).

[0080] The optical body (210) may further include a pair of second surfaces (214) connecting a pair of first surfaces (213) and an incident surface (211). The pair of second surfaces (214) may be connected to both sides of the width direction of the incident surface (211). The pair of second surfaces (214) may be perpendicular to the incident surface (211). The pair of second surfaces (214) may be both sides of the optical body (210).

[0081] The mirror cover (230) can cover the optical body (220). The mirror cover (230) can act as a shield to prevent laser beams emitted from the optical body (220) other than the pressure surface (212) from being exposed to the outside.

[0082] A laser beam can be reflected from the inner surface of the mirror cover (230). That is, a reflective layer (230a) having a predetermined reflectivity can be provided on the inner surface of the mirror cover (230) so that the laser beam is reflected. Accordingly, the mirror cover (230) can reflect the laser beam emitted from the optical body (220) outside the pressure surface (212) inward and collect it once again.

[0083] For example, the mirror cover (230) may be made of copper (Cu) material, and a reflective layer (230a) made of gold (Au) material may be provided on its inner surface. However, the materials of the mirror cover (230) and the reflective layer (230a) are not limited thereto.

[0084] An opening (231) may be formed in the mirror cover (230) to expose the pressure surface (212) of the optical body (210). The opening (213) may face the sealing portion (122) of the object, i.e., the exterior material (120).

[0085] The protrusion (210a) of the optical body (210) can be inserted into the opening (231). Like the protrusion (210a), the opening (231) can be formed long in a direction parallel to the longitudinal direction of the sealing portion (122). By inserting the protrusion (210a) into the opening (231), the mirror cover (230) can be accurately mounted on the optical body (210).

[0086] A reflective layer (230a) may be provided on the inner circumference of the opening (231). Accordingly, a laser beam emitted from the protrusion (210a) to a part other than the pressure surface (212) can be reflected and gathered to the pressure surface (212). However, it is not limited thereto.

[0087] The outermost surface of the protrusion (210a), i.e., the pressure surface (212), may protrude beyond the opening (231) or coincide with the end of the opening (231). Thus, the pressure surface (212) can directly press the sealing portion (122).

[0088] The mirror cover (230) may include a pair of first cover portions (232) that cover a pair of first surfaces (213) and have a distance from each other that decreases as they approach the opening (231). The pair of first cover portions (232) may be located on both sides with the opening (231) in between.

[0089] A reflective layer (230a) may be provided on the inner surface of the first cover portion (232). The first cover portion (232) may cover the first surface (213) of the optical body (210). The first cover portion (232) may have a shape corresponding to the first surface (213).

[0090] More specifically, the reflective layer (230a) provided on the inner surface of the first cover portion (232) can cover the first surface (213) of the optical body (210). Accordingly, a laser beam emitted from the first surface (213) of the optical body (210) can be reflected from the inner surface of the first cover portion (232) into the interior of the optical body (210).

[0091] In the present embodiment, similar to the first surface (213), the first cover portion (232) may be an inclined plane. By forming the first surface (213) and the first cover portion (232) at an angle, a laser beam reflected from the inner surface of the first cover portion (232) can be reflected multiple times within the optical body (210) and smoothly concentrated on the pressure surface (212). If the first surface (213) and the first cover portion (232) are parallel to the incident surface (211), the laser beam reflected from the inner surface of the first cover portion (232) will be trapped between the incident surface (211) and the first surface (213).

[0092] A person skilled in the art may appropriately select the shape of the first surface (213) and the first cover portion (232) so that the laser beam can be well concentrated on the pressure surface (212).

[0093] A pair of first cover portions (232) may have a shape that is symmetric to each other. More specifically, a pair of first cover portions (232) may be symmetric to each other with respect to a virtual line that passes vertically through the center of the opening (231).

[0094] The mirror cover (230) may include a pair of second cover portions (233) that cover a pair of second surfaces (214) and are connected to a first cover portion (232). The pair of second cover portions (233) may be both sides of the mirror cover (230).

[0095] A reflective layer (230a) may be provided on the inner surface of the second cover portion (233). The second cover portion (233) may cover the second surface (214) of the optical body (210). The second cover portion (233) may have a shape corresponding to the second surface (214).

[0096] More specifically, the reflective layer (230a) provided on the inner surface of the second cover portion (233) can cover the second surface (214) of the optical body (210). Accordingly, a laser beam emitted from the second surface (214) of the optical body (210) can be reflected from the inner surface of the second cover portion (233) into the interior of the optical body (210).

[0097] FIG. 5 is an exploded perspective view of a sealing unit according to another embodiment of the present invention.

[0098] Below, content that overlaps with the previously explained material will be appropriately referenced, and the differences will be explained in detail.

[0099] In the case of the sealing unit (200') according to the present embodiment, the first surface (213') of the optical body (210) and the first cover portion (232') of the mirror cover (230) may be convex curved surfaces. The curved surfaces may be formed convexly toward the outside.

[0100] Since the first surface (213') and the first cover portion (232') are formed as convex curved surfaces, the laser beam reflected from the inner surface of the first cover portion (232') can be reflected multiple times within the optical body (210) and smoothly concentrated on the pressure surface (212).

[0101] The radius of curvature of the first surface (213') and the first cover portion (232') may vary depending on the position. A person skilled in the art may appropriately select the shape of the first surface (213') and the first cover portion (232') such that the laser beam can be well concentrated on the pressure surface (212).

[0102] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention.

[0103] Accordingly, the embodiments disclosed in this invention are intended to explain, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments.

[0104] The scope of protection of the present invention shall be interpreted by the claims below, and all technical ideas within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention.

[0105] [Explanation of the symbol]

[0106] 100: Pouch-type secondary battery 120: Pouch-type casing

[0107] 122: Sealing section 200: Sealing unit

[0108] 210: Optical body 210a: Protrusion

[0109] 211: Incident surface 212: Pressurized surface

[0110] 213: Page 1 214: Page 2

[0111] 220: Laser Unit 221: Light Source

[0112] 230: Mirror cover 230a: Reflective layer

[0113] 231: Opening 232: First cover section

[0114] 232: Second cover section

Claims

1. An optical body comprising an incident surface into which a laser beam is incident and a pressurizing surface into which a laser beam is emitted and which pressurizes an object; A laser unit that irradiates a laser beam onto the above-mentioned incident surface; and A sealing unit comprising a mirror cover that covers the optical body and has an opening formed therein where a laser beam is reflected from the inner surface and the pressure surface is exposed.

2. In Paragraph 1, A sealing unit having a reflective layer having a predetermined reflectivity so as to reflect a laser beam on the inner surface of the mirror cover.

3. In Paragraph 1, The laser unit above is a sealing unit comprising a plurality of light sources arranged to face the incident surface.

4. In Paragraph 2, The above laser unit is a sealing unit that is a VCSEL (vertical-cavity surface-emitting laser) module.

5. In Paragraph 1, The above-mentioned pressure surface is formed elongated in one direction, and A sealing unit in which the area of ​​the above-mentioned pressure surface is narrower than the area of ​​the above-mentioned incident surface.

6. In Paragraph 1, The optical body is provided with a protrusion that is inserted into the opening, and The outermost surface of the above-mentioned protrusion is a sealing unit defining the above-mentioned pressure surface.

7. In Paragraph 1, The above-mentioned incident surface and pressure surface are formed parallel to each other in a sealing unit.

8. In Paragraph 1, The above optical body is, A sealing unit further comprising a pair of first surfaces whose distance from each other decreases as they approach the above-mentioned pressure surface.

9. In Paragraph 8, A sealing unit in which the first surfaces of the above pair are inclined planes or convex curved surfaces.

10. In Paragraph 8, The above pair of first surfaces is a sealing unit facing the incident surface with respect to the pressure direction of the pressure surface.

11. In Paragraph 8, The above mirror cover is, A sealing unit comprising a pair of first cover portions that cover the above-mentioned pair of first surfaces and have a mutual distance that decreases as they approach the opening.

12. In Paragraph 11, The above optical body is, A sealing unit that further includes a pair of second surfaces perpendicular to the incident surface, connecting the first surface and the incident surface.

13. In Paragraph 12, The above mirror cover is, A sealing unit comprising a pair of second cover portions that cover the pair of second surfaces and are connected to the first cover portion.

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