Endoscopes and methods for manufacturing endoscopes

Abstract

The present invention comprises: an image sensor having an imaging plane; and a lens that is bonded to the imaging plane with an adhesive and focuses light onto the image sensor. The lens has: a light incidence plane extending in the orthogonal direction orthogonal to the direction along the light axis of the lens; a back plane which is parallel to the light incidence plane and opposes the imaging plane; a recessed part having an opening arranged on the back plane, and a lens inner space arranged between the opening and the incidence plane, the recessed part recessed from the opening toward the incidence plane; an emission part that is arranged in the lens inner space and emits light from the light incidence plane to the imaging plane; a frame part arranged around the opening on the back plane; and a protruding part that protrudes from the frame part in the light axis direction and abuts on the imaging plane.

Description

Technical Field

[0001] The present disclosure relates to an endoscope and a method for manufacturing an endoscope.

Background Art

[0002] In the medical or industrial field, endoscopes for imaging the inside of a patient's body, equipment, or a structure are widespread. In such an endoscope, in an insertion portion inserted into the observation target, light from the imaging site of the observation target is imaged on the imaging surface of an image sensor through an objective lens system. For example, in the medical field, in order to reduce the burden on a subject such as a patient, further reduction in the outer diameter of the insertion portion of an endoscope inserted into the subject's body is important.

[0003] The endoscope of Patent Document 1 has a long and slender insertion portion. The insertion portion of the endoscope of Patent Document 1 has a distal end portion, a curved portion, and a flexible tube portion in order from the distal end side inserted into the subject.

[0004] The endoscope of Patent Document 2 includes an outer cylinder at the distal end portion. An imaging mechanism covered with a filled light-shielding material is provided in the outer cylinder. The imaging mechanism includes an image sensor having a light-receiving portion on one surface, a cover member covering the surface of the image sensor provided with the light-receiving portion, a lens unit optically coupled to the light-receiving portion of the image sensor, and a flexible printed wiring board. The lens unit has an objective cover member, an aperture, a plano-convex lens, and a lens barrel fixing these from the object side. Between the plano-convex lens and the cover member is fixed with an adhesive.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, because the bonding thickness between the lens and the image sensor is difficult to quantify, managing the bonding thickness between the lens and the image sensor is not easy. In particular, with endoscopes of sub-millimeter order diameter, variations in the bonding thickness between the lens and the image sensor reduce the bonding strength. As a result, the lens is more prone to warping, which degrades the image quality of the images captured by the image sensor (in other words, the image quality becomes unstable).

[0007] This disclosure was devised in view of the conventional circumstances described above, and aims to provide an endoscope and an endoscope manufacturing method that can suppress the deterioration of image quality. [Means for solving the problem]

[0008] This disclosure comprises an image sensor having an imaging surface, and a lens bonded to the imaging surface by an adhesive and imaging light onto the image sensor, wherein the lens has a light incident surface extending in a direction perpendicular to the optical axis of the lens, a back surface parallel to the light incident surface and facing the imaging surface, an opening disposed on the back surface, and an internal lens space disposed between the opening and the light incident surface, a recess that is recessed from the opening toward the light incident surface, and a component disposed in the internal lens space that focuses light from the light incident surface onto the imaging surface. The device comprises an emission portion that emits light onto the image plane, a frame portion arranged around the opening on the back surface, and a projection portion that protrudes from the frame portion in the direction of the optical axis and contacts the imaging surface, wherein the projection portion comprises a first projection located at the first corner of the frame portion intersecting the first diagonal of the back surface, a second projection located at the second corner of the frame portion intersecting the first diagonal, a third projection located at the third corner of the frame portion intersecting the second diagonal of the back surface intersecting the first diagonal, and a fourth projection located at the fourth corner of the frame portion intersecting the second diagonal. Furthermore, the image sensor has a rectangular imaging surface, and the lens has a rectangular light incident surface and a rectangular back surface, and is a rectangular prism extending from the light incident surface to the back surface. We provide endoscopes.

[0009] Furthermore, this disclosure includes an image sensor having an imaging surface and an element cover glass covering the imaging surface, and a lens bonded to the element cover glass by an adhesive and imaging light onto the image sensor, wherein the lens has a light incident surface extending in a direction perpendicular to the optical axis direction of the lens, a back surface parallel to the light incident surface and facing the element cover glass, an opening disposed on the back surface, and an internal lens space disposed between the opening and the light incident surface, a recess recessing toward the light incident surface from the opening, and a front element disposed in the internal lens space. The element has an emission portion that emits light from the light incident surface to the imaging surface, a frame portion arranged around the opening on the back surface, and a projection portion that protrudes from the frame portion in the direction of the optical axis and contacts the element cover glass, wherein the projection portion has a first projection located at the first corner of the frame portion intersecting the first diagonal of the back surface, a second projection located at the second corner of the frame portion intersecting the first diagonal, a third projection located at the third corner of the frame portion intersecting the second diagonal of the back surface intersecting the first diagonal, and a fourth projection located at the fourth corner of the frame portion intersecting the second diagonal. Furthermore, the image sensor has a rectangular imaging surface, and the lens has a rectangular light incident surface and a rectangular back surface, and is a rectangular prism extending from the light incident surface to the back surface. We provide endoscopes.

[0010] Furthermore, this disclosure relates to a method for manufacturing an endoscope comprising: an image sensor having an imaging surface; a frame portion disposed on the back surface facing the imaging surface; and a lens having a projection portion disposed on the frame portion, which is bonded to the imaging surface by an adhesive and forms an image of light on the image sensor, the method comprising: a coating step of applying an adhesive to either the frame portion or the imaging surface; an optical axis alignment step of aligning the optical axis of the image sensor with the optical axis of the lens; a contact step of bringing the lens and the imaging surface into contact via the projection portion; and a curing step of curing the adhesive. The lens has a light incident surface extending in a direction perpendicular to the optical axis of the lens, a back surface parallel to the light incident surface and facing the imaging surface, an opening located on the back surface, and an internal lens space located between the opening and the light incident surface, a recess extending inward from the opening toward the light incident surface, an emission portion located in the internal lens space for emitting light from the light incident surface toward the imaging surface, a frame portion located around the opening on the back surface, and a projection portion extending from the frame portion in the direction of the optical axis and in contact with the imaging surface. The aforementioned projection includes a first projection positioned at the first corner of the frame portion intersecting the first diagonal of the back surface, a second projection positioned at the second corner of the frame portion intersecting the first diagonal, a third projection positioned at the third corner of the frame portion intersecting the second diagonal of the back surface intersecting the first diagonal, and a fourth projection positioned at the fourth corner of the frame portion intersecting the second diagonal. Furthermore, the image sensor has a rectangular imaging surface, and the lens has a rectangular light incident surface and a rectangular back surface, and is a rectangular prism extending from the light incident surface to the back surface. The present invention provides a method for manufacturing an endoscope.

[0011] Furthermore, this disclosure relates to a method for manufacturing an endoscope comprising: an image sensor having an imaging surface and an element cover glass covering the imaging surface; a lens having a frame portion disposed on the back surface facing the element cover glass and a projection portion disposed on the frame portion, which is bonded to the element cover glass with an adhesive and forms an image of light on the image sensor, the method comprising: a coating step of applying an adhesive to either the frame portion or the element cover glass; an optical axis alignment step of aligning the optical axis of the image sensor with the optical axis of the lens; and bringing the lens and the element cover glass into contact via the projection portion. The process includes a contact step and a curing step for curing the adhesive, wherein the lens has a light incident surface extending in a direction perpendicular to the optical axis direction of the lens, a back surface parallel to the light incident surface and facing the element cover glass, an opening disposed on the back surface, and an internal lens space disposed between the opening and the light incident surface, a recess that is recessed toward the light incident surface from the opening, an emission part disposed in the internal lens space for emitting light from the light incident surface to the imaging surface, a frame part disposed around the opening on the back surface, and a part that protrudes from the frame part in the direction of the optical axis, Element cover glass The present invention provides a method for manufacturing an endoscope, comprising: an image sensor having a projection that contacts the back surface, the projection having a first projection positioned at the first corner of the frame portion intersecting the first diagonal of the back surface, a second projection positioned at the second corner of the frame portion intersecting the first diagonal, a third projection positioned at the third corner of the frame portion intersecting the second diagonal of the back surface intersecting the first diagonal, and a fourth projection positioned at the fourth corner of the frame portion intersecting the second diagonal; the image sensor having a rectangular imaging surface, and the lens having a rectangular light incident surface and a rectangular back surface, and being a rectangular prism extending from the light incident surface to the back surface. [Effects of the Invention]

[0012] According to this disclosure, it is possible to provide an endoscope and an endoscope manufacturing method that can suppress the deterioration of image quality. [Brief explanation of the drawing]

[0013] [Figure 1] FIG. 1 is a perspective view of a main part of a camera housed in a distal end portion of an endoscope according to Embodiment 1. [Figure 2] FIG. 2 is an exploded perspective view of the endoscope according to Embodiment 1. [Figure 3] FIG. 3 is an upper perspective view of a lens unit according to Embodiment 1. [Figure 4] FIG. 4 is a plan view of the lens unit according to Embodiment 1. [Figure 5] FIG. 5 is a cross-sectional view taken along line A-A of the lens unit according to Embodiment 1. [Figure 6] FIG. 6 is a cross-sectional view taken along line B-B of the lens unit according to Embodiment 1. [Figure 7] FIG. 7 is an explanatory view showing a cross-section taken along line A-A of the lens unit according to Embodiment 1 together with an enlarged view of a main part thereof. [Figure 8A] FIG. 8A is a schematic diagram for explaining the relationship between the protrusion height and the back focus. [Figure 8B] FIG. 8B is a schematic diagram for explaining the relationship between the protrusion height and the back focus. [Figure 8C] FIG. 8C is a schematic diagram for explaining the relationship between the protrusion height and the back focus. [Figure 9] FIG. 9 is a flowchart showing the procedure of a method for manufacturing an endoscope. [Figure 10A] FIG. 10A is an explanatory view showing the states of a lens and an image sensor. [Figure 10B] FIG. 10B is an explanatory view showing the states of a lens and an image sensor. [Figure 10C] FIG. 10C is an explanatory view showing the states of a lens and an image sensor. [Figure 10D] FIG. 10D is an explanatory view showing the states of a lens and an image sensor. [Figure 10E] FIG. 10E is an explanatory view showing the states of a lens and an image sensor. [Figure 10F] FIG. 10F is an explanatory view showing the states of a lens and an image sensor. [Figure 11A] Figure 11A is an explanatory diagram illustrating the behavior of the adhesive during the contact process. [Figure 11B] Figure 11B is an explanatory diagram illustrating the behavior of the adhesive during the contact process. [Figure 11C] Figure 11C is an explanatory diagram illustrating the behavior of the adhesive during the contact process. [Figure 12] Figure 12 is a perspective view of the lens according to Modification 1. [Figure 13] Figure 13 is a perspective view of the lens according to Modification Example 2. [Figure 14] Figure 14 is a perspective view of the lens according to Modification 3. [Modes for carrying out the invention]

[0014] The following describes in detail embodiments of the endoscope and endoscope manufacturing method disclosed herein, with reference to the drawings as appropriate. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters and redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding by those skilled in the art. The accompanying drawings and the following explanation are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims. <Embodiment 1>

[0015] Figure 1 is a perspective view of the main part of the camera unit 13 housed in the tip of the endoscope 11 according to this embodiment. The endoscope 11 according to this embodiment houses the camera unit 13 in its tip (not shown). The camera unit 13 includes a lens 15 which is a hexahedron, or rectangular prism, with each face having a rectangular shape. The lens 15 has a first face 17 which has a rectangular shape, and a second face 19 which is parallel to the first face 17 and also has a rectangular shape. The first face 17 is the incident surface of the lens 15 to which imaging light is incident, and the second face 19 is the back surface of the lens 15. The image sensor 21 is located on the back side of the lens 15 in the camera unit 13. A transmission cable 27, which is made up of multiple electric wires 23 bundled together by a sheath 25, is connected to the back surface of the image sensor 21.

[0016] The image sensor 21 has an imaging surface 21a into which imaging light is incident, and is formed as a rectangle with a side length of, for example, 0.5 mm or less. This makes it possible to manufacture the endoscope 11 as a so-called sub-millimeter camera with an outermost diameter of less than 1 mm.

[0017] The endoscope 11 is formed with a small diameter (for example, a diameter of the sub-millimeter order). This configuration allows the endoscope 11 to be inserted into small body cavities. In other words, the endoscope 11 is equivalent to a flexible endoscope used in medicine. Small body cavities are not limited to blood vessels in the human body, but also include, for example, the ureters, pancreatic ducts, bile ducts, and bronchioles. That is, the endoscope 11 can be inserted into blood vessels, ureters, pancreatic ducts, bile ducts, bronchioles, etc. in the human body. In other words, the endoscope 11 can be used to observe lesions within blood vessels. The endoscope 11 is effective in identifying atherosclerotic plaques. The endoscope 11 can also be applied to observations during cardiac catheterization. Furthermore, the endoscope 11 is effective in detecting thrombi and atherosclerotic yellow plaques.

[0018] In this disclosure, the front side of the endoscope 11 refers to the side facing the subject. The rear side (dorsal side) of the endoscope 11 refers to the side opposite the subject, with the front side of the endoscope 11 in between.

[0019] The endoscope 11 has a camera unit 13 housed in a rigid tip and a transmission cable 27. The camera unit 13 includes a lens unit 31 and an image sensor 21. The camera unit 13 may also have an element cover glass 33 between the lens unit 31 and the image sensor 21. The tip of the endoscope 11 is covered by, for example, a metal tube or a resin molded part (not shown). With this configuration, the tip of the endoscope 11 is formed so that it does not bend or bends only slightly. A flexible part (not shown) extends from the rear side of the tip of the endoscope 11, which bends more easily than the tip. The transmission cable 27 is mainly inserted through the flexible part. The insertion part (not shown) of the endoscope 11 is composed of the tip and the flexible part. A plug part (not shown) that connects to a video processor (not shown) of an endoscope system (not shown) is attached to the rear end of the insertion part of the endoscope 11. The endoscope 11 transmits and receives power and various signals (video signals, control signals, etc.) to and from the video processor via the transmission cable 27 and the plug.

[0020] Figure 2 is an exploded perspective view of the endoscope 11. The lens unit 31 includes an objective cover glass 29 and a lens 15. The objective cover glass 29 is bonded to the front surface (i.e., the first surface 17) of the lens 15. Imaging light from the subject enters the objective cover glass 29. An aperture (not shown) may be provided between the objective cover glass 29 and the lens 15. Alternatively, the endoscope 11 may be constructed by bonding only the lens 15 to the image sensor 21 without the objective cover glass 29 and aperture.

[0021] On the other hand, the element cover glass 33 is integrally bonded and fixed to the front surface of the image sensor 21 (i.e., the surface facing the second surface 19: the imaging surface 21a of the image sensor 21). The image sensor 21, which is thin, for example, 0.5 mm square, can be made easier to handle by integrally bonding and fixing it with the element cover glass 33, thereby suppressing distortion such as warping. The front surface of the element cover glass 33 (i.e., the surface facing the second surface 19) corresponds to the bonded surface 35 that is bonded and fixed to the lens 15. The bonded surface 35 is a rectangle of approximately the same size as the lens 15. The endoscope 11 is assembled in a hexahedron shape (see Figure 1) in which the objective cover glass 29, aperture, lens 15, element cover glass 33, and image sensor 21 are joined together by their rectangular bonding surfaces. Note that if the camera unit 13 does not include the element cover glass 33, the imaging surface 21a corresponds to the bonded surface. The imaging surface 21a and the adhesive surface 35 are formed as rectangles of approximately the same size as, for example, the second surface 19 of the lens 15.

[0022] A transmission cable 27 is connected to the back of the image sensor 21 either before or after it is joined to the lens 15. The transmission cable 27 includes, for example, four wires 23 bundled together by a sheath 25. Each wire 23 includes an insulating coating 37 and a conductor 39 covered by the insulating coating 37. The conductor 39 is exposed from the insulating coating 37 at the end of the wire 23 when the insulating coating 37 is stripped away. The image sensor 21 is connected to the transmission cable 27 by soldering or the like to four conductor connection points (not shown) provided on the back of the image sensor 21, at the ends of the conductors 39.

[0023] Figure 3 is an upper perspective view of the lens unit 31 when the lens 15 is positioned on the upper side. The lens 15 has a recess 41, an output portion 43, and a frame portion 53. The recess 41 has an opening 45, a bottom surface 47, and an internal lens space 49. The opening 45 is formed on the second surface 19 and is a rectangular opening that is substantially similar to the outer shape of the second surface 19. The internal lens space 49 corresponds to an inverted truncated pyramidal space in the recess 41, gradually decreasing in opening area from the opening 45 to the bottom surface 47. In the recess 41, the second surface 19 (see Figure 1) is on the front side, that is, the second surface 19 is recessed from the back surface of the lens 15 toward the incident surface. In other words, the recess 41 is recessed from the opening 45 toward the second surface 19. The bottom surface 47 is parallel to the second surface 19 of the lens 15. The output portion 43 has a top portion 43a and a convex curved surface portion 43b. The convex curved portion 43b rises from the bottom surface 47 toward the second surface 19, that is, toward the back surface of the lens 15. In the direction toward the second surface 19 from the bottom surface 47, the height of the convex curved portion 43b from the bottom surface 47, that is, the height from the bottom surface 47 toward the top portion 43a, is lower than that of the second surface 19. The convex curved portion 43b, as an example of the effective curved surface portion of the lens 15, is for example a part of a sphere, and refracts the light that has passed through the objective cover glass 29 and the aperture (not shown) (i.e., imaging light from the subject) and emits it to the imaging surface (not shown) of the image sensor 21. In this way, the emission portion 43 emits light in the lens internal space 49, that is, in the direction toward the second surface 19 from the bottom surface 47, at a position between the bottom surface 47 and the second surface 19 (see Figure 5). Note that the convex curved portion 43b may be aspherical. The lens 15 is bonded and fixed to the objective cover glass 29 via adhesive 50 on its front surface (i.e., the first surface 17) located on the opposite side from the output section 43.

[0024] Figure 4 is a top view of the lens unit 31. The line segment passing through the top portion 43a and the center of the spherical surface of the convex curved portion 43b of the emission portion 43 passes through the intersection of a pair of diagonals (diagonal B1 and diagonal B2) of the second surface 19 (see Figure 1). The emission portion 43 emits imaging light from the subject incident on the front surface of the objective cover glass 29 toward the image sensor 21. The imaging light emitted from the emission portion 43 is imaged on the imaging surface 21a of the image sensor 21 (see Figures 1 and 2). The lens 15 also has a frame portion 53. The frame portion 53 corresponds to the portion surrounding the recess 41 on the second surface 19 and is formed, for example, as a frame-shaped end surface extending on the same plane as the second surface 19. The frame portion 53 is formed by connecting the straight frame portions 55a, 55b, 55c, and 55d, which are arranged along each side of the rectangle, with the first corner 53a, the second corner 53b, the third corner 53c, and the fourth corner 53d in a ring-like manner around the rectangle. This frame portion 53 is fixed to the imaging surface 21a of the image sensor 21 (or the adhesive surface 35 of the element cover glass 33) via adhesive 51 (see Figure 12). In the following description, when it is not necessary to distinguish between the straight frame portions 55a, 55b, 55c, 55d, ..., they may simply be referred to as "straight frame portion 55".

[0025] The frame portion 53 is provided with protrusions 57a, 57b, 57c, and 57d. Protrusions 57a, 57b, 57c, and 57d are examples of protrusions in this embodiment. The protrusions 57a, 57b, 57c, and 57d protrude from the frame portion 53 in the optical axis direction X1 of the lens 15 (see Figure 2) with a height h (see Figure 7) and contact the image sensor 21, so that the frame portion 53 is parallel to the surface to be bonded 35 or the imaging surface 21a. In this way, since the protrusions 57a, 57b, 57c, and 57d have the same height h, it is easy to position the lens 15 parallel to the image sensor 21. In this embodiment, the protrusions 57a, 57b, 57c, and 57d are provided at the four corners of the frame portion 53, in other words, at the four corners of the second surface 19. Note that the protrusions 57a, 57b, 57c, and 57d may be integrally molded with the lens 15.

[0026] The protrusions 57a, 57b, 57c, and 57d are located at the four corners of the frame portion 53, which has a height h and a rectangular outer shape. Therefore, by bringing the lens 15 into contact with the imaging surface 21a (or the surface to be adhered 35), the lens 15 and the image sensor 21 can be stably positioned parallel to each other.

[0027] Specifically, projection 57a ​​is located at the first corner 53a of the frame portion 53. The first corner 53a corresponds to the point where it intersects with the diagonal B1 among the four corners of the frame portion 53. Projection 57b is located at the second corner 53b of the frame portion 53. Projection 57c is located at the second corner 53c of the frame portion 53. The second corner 53c corresponds to the point where it intersects with the diagonal B1 and is different from the first corner 53a among the four corners of the frame portion 53. The third corner 53b corresponds to the point where it intersects with the diagonal B2 which intersects with the diagonal B1 among the four corners of the frame portion 53. Projection 57d is located at the fourth corner 53d of the frame portion 53. The fourth corner 53d corresponds to the point where it intersects with the diagonal B2 and is different from the third corner 53b among the four corners of the frame portion 53. Projection 57a ​​corresponds to the first projection in this embodiment, and projection 57c corresponds to the second projection in this embodiment. Furthermore, projection 57b corresponds to the third projection in this embodiment, and projection 57d corresponds to the fourth projection in this embodiment.

[0028] The positions of the protrusions 57a, 57b, 57c, and 57d are not limited to these. The four corners of the frame portion 53 each include an outer corner and an inner corner. The four corners have a larger area than the straight frame portions 55a, 55b, 55c, and 55d. An outer corner is the part where the outer edges of the frame portion 53 intersect perpendicularly. An inner corner is the part where the inner edges of the frame portion 53 intersect.

[0029] The projection 57a ​​may be provided along the entire length of the line connecting the outer corner and the inner corner of the first corner 53a. Alternatively, the projection 57a ​​may be provided on only a portion of the line connecting the outer corner and the inner corner of the first corner 53a. By providing the projection 57a ​​on a portion of the outer corner side of the first corner 53a in this way, the first corner 53a, which is larger than the straight frame portion 55a, can be effectively utilized. For example, it becomes possible to apply the adhesive 51 to the frame portion 53 in a continuous, annular shape with a constant width. Furthermore, by applying the adhesive 51 in a continuous, annular shape without interruption, leakage of reflected light from the recess 41 can be suppressed, thereby suppressing stray light. The projections 57b, 57c, and 57d may also be provided along the entire length of the line connecting the outer corner and the inner corner of the frame portion 53, or on only a portion of the line connecting the outer corner and the inner corner of the frame portion 53, similar to the projection 57a.

[0030] The endoscope 11 of this embodiment has a quadrant shape when viewed in plan, that is, in the direction from the second surface 19 to the first surface 17, and has fan-shaped projections 57a, 57b, 57c, and 57d. Furthermore, the projections 57a, 57b, 57c, and 57d are formed in a fan shape centered on the outer corner on a part of the line connecting the outer corner and the inner corner of the frame portion 53. The direction from the second surface 19 to the first surface 17 in the optical axis AX1 of the lens 15 (see Figure 2) corresponds to the first direction of this embodiment.

[0031] Figure 5 is a cross-sectional view of the lens 15 according to this embodiment. Note that Figure 5 shows the cross-section of the lens 15 along line AA (see Figure 4). The lens 15 is fixed to the image sensor 21 via adhesive 51 with its protrusions 57a, 57b, 57c, and 57d (protrusions 57c and 57b are not shown in Figure 5) in contact with the surface to be bonded 35 or the imaging surface 21a (see Figure 2). Therefore, the adhesive 51 adheres and fixes the surface to be bonded 35 or the imaging surface 21a to the frame portion 53 between the protrusions. In addition, in this embodiment, the adhesive 51 adheres and fixes the surface to be bonded 35 or the imaging surface 21a to the inner corner side at the four corners of the frame portion 53, along the line connecting the outer corner and the inner corner. At least a portion of each of the protrusions 57a, 57b, 57c, and 57d is embedded in the adhesive 51. In Embodiment 1, for example, the protrusions 57a, 57b, 57c, and 57d have their quarter-circular arc portions embedded in the adhesive 51.

[0032] The lens unit 31 can be manufactured by bonding together a large-area objective cover glass 29, an aperture array with multiple openings formed vertically and horizontally, and a lens array with multiple recesses 41 and output portions 43 formed vertically and horizontally, and then cutting (dicing) these into lens units (small pieces). In this case, the lens array is bonded and fixed to the aperture array, or to the objective cover glass 29 if no aperture is used. Even in this case, by providing a projection on the front surface of the lens array, the bonding gap between the lens array and the aperture array, or between the lens array and the objective cover glass 29, can be kept constant, and the bonding thickness can be quantified.

[0033] In the lens 15, the quadrant-shaped protrusions 57a, 57b, 57c, and 57d provided at the four corners of the frame portion 53 described above are formed when circular protrusions on the lens array surface, which are formed on all four sides surrounding the ejection portion 43 before dicing, are diced vertically and horizontally through the center of these circular protrusions to become quadrant-shaped.

[0034] Figure 6 is a cross-sectional view of the lens 15 according to this embodiment. Note that Figure 6 shows the cross-section of the lens 15 along the line B1-B1 (see Figure 4). The protrusions 57a, 57b, 57c, and 57d (protrusions 57b and 57d are not shown in Figure 6) protrude from the frame portion 53 at a height h (see Figure 7). Because the protrusions 57a, 57b, 57c, and 57d protrude from the frame portion 53 at the same height h, they come into contact with the front surface of the image sensor 21 (i.e., the imaging surface 21a) or the surface to be adhered 35. With this configuration, the endoscope 11 can position the second surface 19 of the lens 15 parallel to the imaging surface 21a or the surface to be adhered 35 of the image sensor 21 with high precision and flatness. As a result, an even gap corresponding to the height h of the protrusions 57a, 57b, 57c, and 57d is arranged between the frame portion 53 and the imaging surface 21a or the surface to be bonded 35 of the image sensor 21, in the circumferential direction of the frame portion 53, that is, around the opening 45 in the frame portion 53. When the adhesive 51 fills the gap between the frame portion 53 and the imaging surface 21a or the surface to be bonded 35 of the image sensor 21, the lens 15 and the image sensor 21 are bonded and fixed in the endoscope 11.

[0035] In the endoscope 11, the lens 15 and the image sensor 21 are bonded together with a thickness equal to the height h of the projection 57. This makes it extremely easy to control the bonding thickness between the lens 15 and the image sensor 21 in this embodiment. Therefore, in the endoscope 11, a stable bonding force can be ensured between the lens 15 and the image sensor 21, and the lens 15 is less likely to warp, thus suppressing image quality degradation (unstable image quality) caused by variations in bonding thickness.

[0036] Figure 7 is an explanatory diagram showing the AA cross-section of the lens 15 according to this embodiment (see Figure 4) and an enlarged view of the main part of the lens 15. In this embodiment, the protrusions 57a, 57b, 57c, and 57d have a common configuration except for their position in the frame portion 53, so the explanation will be given using protrusion 57d as an example.

[0037] The height h of the projection 57d can be set to, for example, 0.001 to 0.005 mm. The lower limit of 0.001 mm for the height h of the projection 57d means that the projection 57d is always present on the lens 15. The adhesive 51 is applied to the frame portion 53 having the projection 57d with a thickness of, for example, 0.020 to 0.050 mm. In this embodiment, an upper limit is set on the application thickness of the adhesive 51 in order to prevent contamination of the optically effective area Oa (see Figure 11C) of the endoscope 11 with the adhesive 51. In this embodiment, the upper limit on the application thickness of the adhesive 51 is, for example, 0.050 mm.

[0038] Furthermore, multiple types of lenses 15 may be manufactured by changing the height h of the protrusions 57a, 57b, 57c, and 57d. By changing the height h of the protrusions 57a, 57b, 57c, and 57d, the lenses 15 can be used with different back focus specifications. In other words, the endoscope 11 can obtain different depths of field by changing only the height h of the protrusions 57a, 57b, 57c, and 57d. In addition, by changing the height h of the protrusions 57a, 57b, 57c, and 57d, it becomes easy to create a lineup of endoscopes 11 for multiple applications (e.g., for digestive systems, respiratory systems, intravascular plaque identification, intravascular pathway visualization, etc.).

[0039] Specifically, the back focus of the endoscope 11 can be set by bringing the protrusions 57a, 57b, 57c, and 57d into contact with the image sensor 21. Since the protrusions 57a, 57b, 57c, and 57d protrude from the frame 53 at a height h, the distance to the subject at which the focus is best achieved (imaging distance) changes depending on the height h of the protrusions 57a, 57b, 57c, and 57d. Figures 8A, 8B, and 8C are schematic diagrams illustrating the relationship between the height h of the protrusions 57a, 57b, 57c, and 57d and the back focus of the lens 15. In the following explanation, when it is not necessary to distinguish between the protrusions 57a, 57b, 57c, and 57d, they may simply be referred to as "protrusion 57".

[0040] Here, as shown in Figure 8B, we assume that the distance from the subject to the lens 15 (more precisely, the front principal point) is a, and the distance from the lens 15 (more precisely, the rear principal point) to the image plane 67 is b. In this case, if the front focal point f and the rear focal point f of the lens 15 are the same, the imaging equation of the lens (1 / a + 1 / b = 1 / f) holds true. The image plane 67 corresponds to, for example, the imaging surface 21a.

[0041] Therefore, as shown in Figure 8A, as the distance b to the image plane 67 decreases (b-δ1), the distance a to the subject increases (a+δ2). In other words, if the back focus distance of lens 15 is short (the height h of the protrusion 57 is low), the subject distance at which lens 15 can focus becomes farther away. Also, as shown in Figure 8C, as the distance b to the image plane 67 increases (b-δ3), the distance a to the subject decreases (a-δ4). In other words, if the back focus distance of lens 15 is long (the height h of the protrusion 57 is high), the subject distance at which lens 15 can focus becomes closer. However, δ1, δ2, δ3, and δ4 are positive numbers.

[0042] As a result, in Embodiment 1, by changing only the height h of the projection 57, it is possible to easily realize a lineup of endoscopes 11 for long-distance imaging, medium-distance imaging, and short-distance imaging (for example, for the digestive system, respiratory system, intravascular plaque identification, intravascular pathway visualization, etc.) by changing the imaging distance.

[0043] Furthermore, by offering other types of lenses 15 (for example, an output section having a convex curved surface with a different curvature), it becomes possible to further enhance the variety of lenses 15 and the types of back focus for lenses 15, thereby expanding the product lineup of the endoscope 11.

[0044] Next, the method for manufacturing the endoscope 11 will be described. Figure 9 is a flowchart showing the procedure for manufacturing the endoscope 11 according to Embodiment 1. Figures 10A, 10B, 1C, 10D, 10E, and 10F are explanatory diagrams showing the state of the lens 15 and the image sensor 21 during the manufacturing process of the endoscope 11.

[0045] The endoscope manufacturing method according to Embodiment 1 uses a lens 15 having a recess 41 on its second surface 19. An ejection portion 43 is formed in the recess 41. The ejection portion 43 has a convex curved surface portion 43b that rises from the bottom surface 47. A frame portion 53 surrounding the recess 41 is provided with protrusions 57 (for example, protrusions 57a, 57b, 57c, 57d, etc.).

[0046] In the endoscope manufacturing method, the lens 15 and the image sensor 21 are first chucked (st1) in the holding step. As shown in Figure 10A, in the holding step (st1), the image sensor 21 is held by air suction using the sensor chuck 61, and the lens unit 31 is held by air suction using the lens chuck 63. The image sensor 21 is held by suction on the surface opposite to the bonding surface 35 (or imaging surface 21a). The front surface of the objective cover glass 29 of the lens unit 31 is held by suction.

[0047] Next, in the endoscope manufacturing method, in the coating step, adhesive 51 is applied to either the imaging surface 21a or the surface to be bonded 35 of the image sensor 21, or to the frame portion 53 of the lens 15 (st2). As shown in Figure 10B, in the coating step (st2), for example, the adhesive 51 is applied in a rectangular frame shape to the front surface (i.e., the surface to be bonded 35) of the element cover glass 33. In the coating step, the adhesive 51 is applied to a predetermined thickness (height) within a range that does not extend beyond the projection area of ​​the frame portion 53. At this time, the lens unit 31 is inverted upside down to prevent the adhesive 51 from sagging due to gravity. The adhesive 51 is applied within a range corresponding to the inside of the frame portion 53 of the lens 15. The adhesive 51 can be applied in a single or double frame shape, in a roughly rectangular shape. For example, an ultraviolet-curable adhesive 51 is used as the adhesive 51. In this embodiment, a roughly rectangular shape corresponds to a shape in which each corner of the rectangular frame is chamfered.

[0048] Next, in the endoscope manufacturing method, a proximity step (st3) is performed to bring the lens 15 and the image sensor 21 closer together. As shown in Figure 10C, in the proximity step (st3), for example, the sensor chuck 61 and the lens chuck 63 are moved by actuators (not shown) to bring the image sensor 21 and the lens unit 31 closer together so that the frame portion 53 and the adhesive surface 35 (or imaging surface 21a) are closer together. It is preferable that the movement be a relative movement in which the image sensor 21, to which the adhesive 51 has been applied, is fixed, and the lens unit 31, with the frame portion 53 facing downwards, is processed from above.

[0049] After the approach process (st3), in the endoscope manufacturing method, the optical axis alignment process aligns the optical axis AX1 of the lens 15 (see Figure 2) with the optical axis AX2 of the image sensor 21 (see Figure 2) (st4). As shown in Figure 10D, in the optical axis alignment process (st4), the optical axis AX1 of the lens 15 (see Figure 2) and the optical axis AX2 of the image sensor 21 (see Figure 2) are aligned by matching the outer shapes of both the lens 15 and the image sensor 21. The second surface 19 of the lens 15 and the bonding surface 35 of the image sensor 21 are formed as rectangles of approximately the same size. The optical axis AX1 of the lens 15 is the axis that passes through the intersection of a pair of diagonals of the second surface 19 in the Z direction perpendicular to the second surface 19 (see Figure 10D). The optical axis AX2 of the image sensor 21 is an axis that passes through the intersection of a pair of diagonals of the adhesive surface 35 in a direction perpendicular to the adhesive surface 35 (or imaging surface 21a) (Z direction).

[0050] In the optical axis alignment process, assuming the axis of the camera unit 13 (see Figure 1) is the optical axis 59, the lens 15 and image sensor 21 are moved so that the amount of displacement of the outer shapes of the lens 15 and image sensor 21 observed from two orthogonal directions (X direction and Y direction) passing through the optical axis 59 is equal in a plane perpendicular to the optical axis 59 (XY plane). In this way, the optical axis AX1 of the lens 15 and the optical axis AX2 of the image sensor 21 are indirectly aligned. By indirectly aligning the optical axis AX1 of the lens 15 and the optical axis AX2 of the image sensor 21, the optical axis 59 is formed. The camera unit 13 may be rotationally symmetric with respect to the optical axis 59. In this way, the optical axis AX1 and the optical axis AX2 can be aligned with higher precision, and thus the displacement of the optical axis caused by manufacturing errors (including tolerances) of the lens 15 and image sensor 21 can be suppressed.

[0051] Furthermore, in the optical axis alignment process of this embodiment, it is not necessary to align the lens 15 and the image sensor 21 while visually observing the captured image output from the image sensor 21. Therefore, it is not necessary to connect the transmission cable 27 before joining the lens 15 and the image sensor 21, thereby suppressing a decrease in work efficiency due to the addition of cleaning processes, equipment, etc.

[0052] Next, in the endoscope manufacturing method, the lens 15 and the image sensor 21 are brought into contact via the projection 57 during the contact process (st5). As shown in Figure 10E, in the contact process (st5), the frame portion 53 of the lens 15 is brought into contact with the imaging surface 21a or the surface to be bonded 35. Since the projection 57 is positioned on the frame portion 53, the lens 15 is brought into contact with the image sensor 21 via the projection 57, or via the imaging surface 21a or the surface to be bonded 35. As a result, the adhesive 51 applied to the imaging surface 21a or the surface to be bonded 35 is compressed to approximately the height of the projection 57 and spread to cover the entire surface of the frame portion 53.

[0053] When the lens 15 and the image sensor 21 are brought into contact with each other, a plurality of protrusions 57 provided on the frame portion 53 of the lens 15 simultaneously come into contact with the adhesive surface 35 of the image sensor 21. At least a part of the protrusion 57 is embedded in the adhesive 51. Note that all of the protrusions 57 may be embedded in the adhesive 51.

[0054] FIGS. 11A, 11B, and 11C are explanatory diagrams showing the behavior of the adhesive 51 in the contact process. As shown in FIG. 11A, in the coating process, the adhesive 51 is coated thicker than the height h of the protrusion 57. Here, it is assumed that the adhesive 51 is coated with a cross-sectional area of a coating width m and a coating height n in any cross-section orthogonal to the longitudinal direction of the linear end face 55. However, the coating width m is smaller than the end face width c of the linear end face 55 (m < c). Also, the coating height n is higher than the height h of the protrusion 57 (n > h).

[0055] In the contact process, as the lens 15 and the image sensor 21 approach each other, the adhesive 51 is sandwiched between the frame portion 53 and the adhesive surface 35 (or the imaging surface 21a) and crushed. The adhesive 51 is extended (i.e., stretched) in a direction parallel to the frame portion 53 and the adhesive surface 35 (or the imaging surface 21a) while being in close contact with the frame portion 53 and the adhesive surface 35 (or the imaging surface 21a).

[0056] In the lens 15 and the image sensor 21, when the protrusion 57 comes into contact with the adhesive surface 35 (or the imaging surface 21a), the approach of the lens 15 and the image sensor 21 closer than the height h of the protrusion 57 is restricted. Therefore, the adhesive surface 35 (or the imaging surface 21a) is positioned with respect to the entire circumference of the frame portion 53 while maintaining an adhesive thickness corresponding to the height h of the protrusion 57.

[0057] During the contact process, the adhesive 51 deforms, with its cross-sectional area before spreading having a recess-side flow portion V2, an end-face joint portion V1, and an outer-shaped flow portion V3. Of these, the outer-shaped flow portion V3 can be removed by trimming before or after the curing process. On the other hand, the recess-side flow portion V2 cannot be removed because the recess 41 becomes a sealed space. The recess-side flow portion V2 remains in the non-interference region Ea, spaced away from the lens 15's output portion 43, by a distance d, because the cross-sectional area of ​​the adhesive 51 is set to be less than or equal to a certain amount beforehand. In other words, to prevent the adhesive 51 from entering or contaminating the optically effective area Oa, an upper limit is set on its thickness (coating width m and coating height n in the cross-sectional area) during the contact process.

[0058] Next, in the endoscope manufacturing method, the optical axis adjustment process fine-tunes the optical axis AX1 of the lens 15 and the optical axis AX2 of the image sensor 21. In the optical axis adjustment process (st6), the lens 15 and the image sensor 21 are fine-tuned again so that the amount of misalignment of the external shapes of the lens 15 and the image sensor 21, as observed from two orthogonal directions (X direction and Y direction) passing through the optical axis 59, is equal. In this way, the optical axis AX1 of the lens 15 and the optical axis AX2 of the image sensor 21 are finally aligned with high precision (in other words, the optical axis AX1 and the optical axis AX2 are arranged coaxially with the optical axis AX59). Note that this optical axis adjustment process (st6) can be omitted if there is no misalignment of the external shapes of the lens 15 and the image sensor 21. Also, if this optical axis adjustment process (st6) is prioritized, the optical axis alignment process (st4) can be omitted.

[0059] Next, in the endoscope manufacturing method, the adhesive 51 is cured in the curing process (st7). As shown in Figure 10F, in the curing process (st7), the adhesive 51 is cured by UV irradiation. For UV irradiation, a light source 65 that emits light in the wavelength range that cures the UV-curable adhesive 51 is used. Due to this UV irradiation, the lens 15 and the image sensor 21 are fixed together with a uniform adhesive thickness via the adhesive 51 which has solidified to a thickness of the height h of the protrusion 57, and the frame portion 53 and the imaging surface 21a or the surface to be bonded 35 are fixed together. As a result, the lens 15 is integrally fixed to the image sensor 21.

[0060] Thus, in the endoscope 11, the lens 15 and the image sensor 21 are solidified with a thickness equal to the height h of the projection 57, making it easy to quantify the bonding thickness between the lens 15 and the image sensor 21. In this way, in this embodiment, it becomes extremely easy to manage the bonding thickness between the lens 15 and the image sensor 21. Therefore, in the endoscope 11, a stable bonding force can be ensured between the lens 15 and the image sensor 21, and the lens 15 is less likely to warp, thus suppressing image quality degradation (unstable image quality) caused by variations in bonding thickness.

[0061] <Example 1> Furthermore, as shown in the following modified example, protrusions 57e, 57g, 57f, and 57h with modified shapes and arrangements may be provided on the second surface 19 of the lens 15. Protrusions 57e, 57g, 57f, and 57h are examples of protrusions in this modified example. Figure 12 is a perspective view of the lens 15 according to Modified Example 1. The frame portion 53 of this modified example has straight frame portions 55e, 55g, 55f, and 55h. The straight frame portion 55e corresponds to a straight end surface located between the first corner 53e and the second corner 53f of the frame portion 53. The straight frame portion 55e corresponds to the first straight frame portion in this modified example. The straight frame portion 55g corresponds to a straight end surface located parallel to the straight frame portion 55e. The straight frame portion 55g corresponds to the second straight frame portion in this modified example. The straight frame portion 55f corresponds to a straight end surface perpendicular to the straight frame portions 55e and 55g. The straight frame section 55f corresponds to the third straight frame section in this modified example. The straight frame section 55h corresponds to a straight end face arranged parallel to the straight frame section 55f. The straight frame section 55h corresponds to the fourth straight frame section in this modified example.

[0062] The projection 57e is located in the center of the straight frame portion 55e. The projection 57e corresponds to the first projection in this modified example. The projection 57g is located in the center of the straight frame portion 55g. The projection 57g corresponds to the second projection in this modified example. The projection 57f is located in the center of the straight frame portion 55f. The projection 57f corresponds to the third projection in this modified example. The projection 57h is located in the center of the straight frame portion 55h. The projection 57h corresponds to the fourth projection in this modified example. Note that the projection 57e may be provided in the center of the straight frame portion 55e in the longitudinal direction. In this case, the projection 57e can be formed as a square with the width c of the end face of the straight end face 55 as one side. The projections 57g, 57f, and 57h may also be formed as squares with the width c of the end face as one side, similar to the projection 57e. The projections 57e, 57g, 57f, and 57h may be integrally molded with the lens 15.

[0063] In this way, by positioning the protrusion 57 in the center of the frame portion 53, adhesive 51 is applied to the four corners of the frame portion 53. In the modified example 1, the bonding area between the lens 15 and the image sensor 21 by the adhesive 51 can be increased, thereby improving the adhesive strength between the lens 15 and the image sensor 21.

[0064] <Modification 2> Figure 13 is a perspective view of the lens 15 according to Modification 2. The frame portion 53 of this modification has straight frame portions 55j, 55k, 55m, and 55n. The straight frame portion 55j corresponds to a straight end face located between the first corner 53j and the second corner 53n of the frame portion 53. The straight frame portion 55j corresponds to the first straight frame portion according to this modification. The straight frame portion 55m corresponds to a straight end face located parallel to the straight frame portion 55j. The straight frame portion 55m corresponds to the second straight frame portion according to this modification. The straight frame portion 55k corresponds to a straight end face perpendicular to the straight frame portions 55j and 55m. The straight frame portion 55k corresponds to the third straight frame portion according to this modification. The straight frame portion 55n corresponds to a straight end face located parallel to the straight frame portion 55k. The straight frame portion 55n corresponds to the fourth straight frame portion according to this modification.

[0065] The projection 57j is located at one end of the straight frame portion 55j, in other words, at the first corner 53j of the frame portion 53. The projection 57j corresponds to the first projection in this modified example. The projection 57n is located at the other end of the straight frame portion 55j, in other words, at the second corner 53n of the frame portion 53. The projection 57n corresponds to the second projection in this modified example. The projection 57m is located in the center of the straight frame portion 55m. The projection 57m corresponds to the third projection in this modified example.

[0066] Thus, the protrusions 57j, 57m, and 57n are provided on at least a portion of at least two parallel straight frame sections among the straight frame sections 55j, 55k, 55m, and 55n that constitute the frame section 53. The protrusions 57j, 57m, and 57n are examples of the protrusions in this modified example. For example, the protrusion 57j is located at one end of the straight frame section 55j in the longitudinal direction. The protrusion 57n is located at the other end of the straight frame section 55j in the longitudinal direction. Furthermore, the protrusion 57m is located in the center of the straight frame section 55m in the longitudinal direction, parallel to the straight frame section 55j. In this case, the protrusions 57j and 57n can be formed in a quarter-circle shape, or a fan shape. Alternatively, the protrusion 57m can be formed in a square shape with the width c of the end face of the straight frame section 55m as one side. Note that the protrusions 57j, 57m, and 57n may be integrally molded with the lens 15.

[0067] In this modified version, the lens 15 and the image sensor 21 can be positioned parallel to each other by arranging the three protrusions 57 on the frame portion 53. This increases the bonding area between the lens 15 and the image sensor 21 by the adhesive 51, and further improves the adhesive strength. As a result, in this modified version, the lens 15 is less likely to warp, and deterioration of image quality (unstable image quality) can be suppressed.

[0068] <Variation 3> Figure 14 is a perspective view of the lens 15 according to Modification 3. The frame portion 53 of this modification has straight frame portions 55r, 55s, 55t, and 55u. The straight frame portion 55r corresponds to a straight end face located between the first corner 53r and the second corner 53s of the frame portion 53. The straight frame portion 55r corresponds to the first straight frame portion according to this modification. The straight frame portion 55t corresponds to a straight end face located parallel to the straight frame portion 55r. The straight frame portion 55t corresponds to the second straight frame portion according to this modification. The straight frame portion 55s corresponds to a straight end face perpendicular to the straight frame portions 55r and 55t. The straight frame portion 55s corresponds to the third straight frame portion according to this modification. The straight frame portion 55u corresponds to a straight end face located parallel to the straight frame portion 55s. The straight frame portion 55u corresponds to the fourth straight frame portion according to this modification.

[0069] The projection 57u is arranged along the entire length of the straight frame portion 55u. The projection 57u corresponds to the first projection in this modified example. The projection 57s is arranged along the entire length of the straight frame portion 55s. The projection 57s corresponds to the second projection in this modified example. Thus, in this modified example, the projections 57u and 57s are provided along the entire length in the longitudinal direction of the straight frame portions 55u and 55s, which are arranged parallel to each other in the frame portion 53.

[0070] The projection 57u does not necessarily have to extend along the entire length of the straight frame portion 55u in the longitudinal direction. The same applies to the projection 57s. For example, the projection 57u may be positioned near the center in the longitudinal direction from one end of the straight frame portion 55u (i.e., from the first corner 53r of the frame portion 53 to the center of the straight frame portion 55u). The projection 57s may be positioned near the center in the longitudinal direction from the other end of the straight frame portion 55s (i.e., from the third corner 53t of the frame portion 53 to the center of the straight frame portion 55s). In other words, in this modified example, the projection 57u is positioned extending in the longitudinal direction of the straight frame portion 55u, and the projection 57s is positioned extending in the longitudinal direction of the straight frame portion 55s. The projections 57u and 57s may be integrally molded with the lens 15. The projections 57u and 57s are examples of projections in this modified example.

[0071] In this modified example, the amount of adhesive 51 applied can be reduced compared to when it is applied to the entire circumference of the frame portion 53. In this modified endoscope 11, the adhesive 51 is applied only to the two parallel straight frame portions 55. Therefore, the amount of adhesive 51 that spills out onto the recessed side or the outer edge can be reduced, suppressing the spillage of adhesive 51 into the optically effective area Oa (see Figure 14C) and suppressing the deterioration of image quality.

[0072] As described in Modifications 1, 2, and 3, in the endoscope 11, the projections 57 are provided on at least a portion of at least two of the four parallel straight frame sections 55. More specifically, if the projections 57 have a small area, it is preferable to arrange three or more of them on the frame section 53. If the projections 57 have a large area, there can be two or more of them on the frame section 53. Here, a projection 57 with a small area corresponds to a projection 57 of an area where it is difficult to stably maintain the parallelism between the second surface 19 and the surface to be adhered 35 (or imaging surface 21a) when there are two projections 57. A projection 57 with a large area corresponds to a projection 57 of an area where it is possible to stably maintain the parallelism between the second surface 19 and the surface to be adhered 35 (or imaging surface 21a) even when there are two projections 57.

[0073] Although various embodiments have been described above with reference to the drawings, it goes without saying that this disclosure is not limited to such examples. It is clear to those skilled in the art that various modifications, alterations, substitutions, additions, deletions, and equivalents can be conceived within the scope of the claims, and these are also understood to fall within the technical scope of this disclosure. Furthermore, the components of the various embodiments described above can be combined arbitrarily without departing from the spirit of the invention.

[0074] Some or all of the above embodiments may also be described as follows, but are not limited to the following: (Note 1) An image sensor having an imaging surface, The system comprises a lens bonded to the imaging surface by an adhesive and which focuses light onto the image sensor, The aforementioned lens is, The light incident surface of the aforementioned lens extends in a direction perpendicular to the optical axis direction, A back surface that is parallel to the light incident surface and faces the imaging surface, The lens has an opening located on the back surface and an internal lens space located between the opening and the light incident surface, and a recess that is recessed from the opening toward the light incident surface, An emission unit is arranged in the lens's internal space and emits light from the light incident surface to the imaging surface, A frame portion is arranged around the opening on the rear surface, It has a projection that protrudes from the frame portion in the direction of the optical axis and contacts the imaging surface, Endoscope. (Note 2) An image sensor having an imaging surface and an element cover glass covering the imaging surface, The element is bonded to the cover glass by an adhesive and comprises a lens that forms an image of light on the image sensor, The aforementioned lens is, The light incident surface of the aforementioned lens extends in a direction perpendicular to the optical axis direction, The back surface is parallel to the light incident surface and faces the element cover glass, The lens has an opening located on the back surface and an internal lens space located between the opening and the light incident surface, and a recess that is recessed from the opening toward the light incident surface, An emission unit is arranged in the lens's internal space and emits light from the light incident surface to the imaging surface, A frame portion is arranged around the opening on the rear surface, It has a projection that protrudes from the frame portion in the direction of the optical axis and contacts the element cover glass, Endoscope. (Note 3) The emission portion has a top portion that is positioned between the back surface and the light incident surface with respect to the optical axis, The endoscope described in Appendix 1 or 2. (Note 4) The emission portion has a convex curved surface portion that rises in a first direction toward the back surface from the light incident surface with respect to the optical axis, The aforementioned top portion is located on the convex curved surface portion. The endoscope described in Appendix 3. (Note 5) The aforementioned recess is It has a bottom surface that is located between the back surface and the light incident surface in the optical axis direction and is positioned closer to the light incident surface than the top surface, The aforementioned convex curved surface portion is The following are raised from the bottom surface in the first direction: The endoscope described in Appendix 4. (Note 6) The aforementioned convex curved surface is a sphere. An endoscope as described in Appendix 4 or 5. (Note 7) The image sensor has a rectangular imaging surface. The lens has a rectangular shape for both the light incident surface and the back surface, and a rectangular prism extending from the light incident surface to the back surface. An endoscope as described in any one of the items 1 to 6 of the appendix. (Note 8) The aforementioned projection is A first projection is positioned at the first corner of the frame portion that intersects with the first diagonal of the back surface, A second projection is positioned at the second corner of the frame portion intersecting the first diagonal, A third projection is positioned at the third corner of the frame portion that intersects with the second diagonal of the back surface which intersects with the first diagonal, A fourth projection is located at the fourth corner of the frame portion intersecting the second diagonal, The endoscope described in Appendix 7. (Note 9) The first projection, the second projection, the third projection, and the fourth projection are The shape, when viewed in a first direction from the back surface toward the light incident surface with respect to the optical axis, is fan-shaped. The endoscope described in Appendix 8. (Note 10) The aforementioned frame portion is It comprises a first straight frame portion positioned between the first corner and the second corner of the back surface, a second straight frame portion positioned parallel to the first straight frame portion, a third straight frame portion perpendicular to the first and second straight frame portions, and a fourth straight frame portion positioned parallel to the third straight frame portion. The aforementioned projection is It has a first projection positioned in the first straight frame section, a second projection positioned in the second straight frame section, a third projection positioned in the third straight frame section, and a fourth projection positioned in the fourth straight frame section. The endoscope described in Appendix 7. (Note 11) The aforementioned opening is It is a rectangle similar to the aforementioned back surface, The first projection is positioned in the central part of the first straight frame portion, The second projection is positioned in the center of the second straight frame portion. The third projection is positioned in the central part of the third straight frame portion, The fourth projection is located in the center of the fourth straight frame portion. The endoscope described in Appendix 10. (Note 12) The first projection, the second projection, the third projection, and the fourth projection are The shape, when viewed in the first direction from the back surface toward the light incident surface with respect to the optical axis, is a rectangle. The endoscope described in Appendix 10 or 11. (Note 13) The aforementioned opening is It is a rectangle similar to the aforementioned back surface, The aforementioned frame portion is It comprises a first straight frame portion positioned between the first corner and the second corner of the back surface, a second straight frame portion positioned parallel to the first straight frame portion, a third straight frame portion perpendicular to the first and second straight frame portions, and a fourth straight frame portion positioned parallel to the third straight frame portion. The aforementioned projection is It has a first projection positioned at the first corner, a second projection positioned at the second corner, and a third projection positioned at the second straight frame portion, The endoscope described in Appendix 7. (Note 14) The first projection and the second projection are The shape, when viewed in the first direction from the back surface toward the light incident surface with respect to the optical axis, is fan-shaped. The third projection is, The shape when viewed in the first direction is a rectangle. The endoscope described in Appendix 13. (Note 15) The aforementioned frame portion is It comprises a first straight frame portion positioned between the first corner and the second corner of the back surface, a second straight frame portion positioned parallel to the first straight frame portion, a third straight frame portion perpendicular to the first and second straight frame portions, and a fourth straight frame portion positioned parallel to the third straight frame portion. The aforementioned projection is The third linear frame portion has a first projection that extends in the longitudinal direction, and the fourth linear frame portion has a second projection that extends in the longitudinal direction, The endoscope described in Appendix 7. (Note 16) The aforementioned frame portion is This is a frame-shaped end surface that is arranged on the same plane as the aforementioned back surface. An endoscope as described in any one of the items 1 through 15 of the appendix. (Note 17) An image sensor having an imaging surface, A method for manufacturing an endoscope comprising a frame portion disposed on the back surface facing the imaging surface, and a lens having a projection portion disposed on the frame portion, which is bonded to the imaging surface by an adhesive and forms an image on the image sensor, A coating step of applying adhesive to either the frame portion or the imaging surface, An optical axis alignment step of aligning the optical axis of the image sensor with the optical axis of the lens, A contact step in which the lens and the imaging surface are brought into contact via the aforementioned projection, A curing step for curing the adhesive, Endoscope manufacturing method. (Note 18) An image sensor having an imaging surface and an element cover glass covering the imaging surface, A method for manufacturing an endoscope comprising a frame portion disposed on the back surface facing the element cover glass, and a projection portion disposed on the frame portion, which is bonded to the element cover glass with an adhesive and forms an image of light on the image sensor, A coating step of applying adhesive to either the frame portion or the element cover glass, An optical axis alignment step of aligning the optical axis of the image sensor with the optical axis of the lens, A contact step in which the lens and the element cover glass are brought into contact via the projection, A curing step for curing the adhesive, Endoscope manufacturing method. (Note 19) It is formed by a hexahedron in which the outer shape of each face is a square, and the first face of one of these squares is a lens into which the imaging light is incident, The system comprises an image sensor bonded to a second surface of the lens, which is provided parallel to the first surface, and to which the imaging light is incident, The aforementioned lens is, The recess formed by indenting the second surface, A convex curved surface portion that protrudes lower than the second surface from the bottom surface of the recess and emits the imaging light toward the image sensor, The portion surrounding the recess on the second surface, and the frame-shaped end face which is fixed to the image sensor via adhesive, It has a plurality of protrusions that project from the frame-shaped end face and contact the image sensor, Endoscope. (Note 20) Each of the aforementioned multiple protrusions extends from the frame-shaped end face at the same height. The endoscope described in Appendix 19. (Note 21) Each of the aforementioned multiple protrusions is provided at the four corners of the frame-shaped end face, The endoscope described in Appendix 19. (Note 22) Each of the aforementioned multiple protrusions is provided spaced apart from a portion of the four straight end faces that constitute the frame-shaped end face. The endoscope described in Appendix 19. (Note 23) Each of the aforementioned multiple protrusions is provided at the longitudinal center of each of the four linear end faces, The endoscope described in Appendix 22. (Note 24) Some of the aforementioned multiple protrusions are provided at each of the longitudinal ends of one of the linear end faces, The remaining of the aforementioned multiple protrusions are provided in the longitudinal center of a linear end face parallel to one of the linear end faces, The endoscope described in Appendix 22. (Note 25) Each of the aforementioned multiple protrusions is provided along the entire longitudinal length of the two parallel linear end faces. The endoscope described in Appendix 22. (Note 26) A method for manufacturing an endoscope comprising a hexahedron formed with each face having a quadrilateral shape, a lens into which imaging light is incident on the first face of one of the quadrilaterals, and an image sensor mounted on the second face of the lens, which is provided parallel to the first face, and into which the imaging light is incident, A holding step of chucking the lens and the image sensor, A coating step of applying adhesive to either the frame-shaped end face surrounding the recess formed by the recess of the second surface or the surface to be bonded in the image sensor, A process of aligning the optical axes of the lens and the image sensor, A contact step in which the lens and the image sensor are brought into contact via each of the plurality of protrusions provided on the frame-shaped end face, A curing step for curing the adhesive, Endoscope manufacturing method.

[0075] This application claims priority based on Japanese Patent Application No. 2021-113080, filed on 7 July 2021, and incorporates all of its disclosures herein. [Industrial applicability]

[0076] This disclosure is useful for endoscopes and methods for manufacturing endoscopes that can suppress image quality degradation. [Explanation of Symbols]

[0077] 11 Endoscopy 13 Camera Section 15 lenses 17 Page 1 19 Side 2 21 Image Sensor 21a Imaging surface 31 Lens Unit 35 Adhesive surface 41 Recess 43. Ejection section 47 Bottom 51 Adhesive 53 Frame section 55a, 55b, 55c, 55d Straight frame section 57a, 57b, 57c, 57d protrusions 59 Optical axis

Claims

1. An image sensor having an imaging surface, A lens is bonded to the imaging surface by an adhesive and focuses light onto the image sensor, Equipped with, The aforementioned lens is, The light incident surface of the aforementioned lens extends in a direction perpendicular to the optical axis direction, A back surface that is parallel to the light incident surface and faces the imaging surface, The lens has an opening located on the back surface and an internal lens space located between the opening and the light incident surface, and a recess that is recessed from the opening toward the light incident surface, An emission unit is arranged in the lens's internal space and emits light from the light incident surface to the imaging surface, A frame portion is arranged around the opening on the rear surface, It has a projection that protrudes from the frame portion in the direction of the optical axis and contacts the imaging surface, The aforementioned projection is A first projection is positioned at the first corner of the frame portion that intersects with the first diagonal of the back surface, A second projection is positioned at the second corner of the frame portion intersecting the first diagonal, A third projection is positioned at the third corner of the frame portion that intersects with the second diagonal of the back surface which intersects with the first diagonal, It has a fourth projection positioned at the fourth corner of the frame portion intersecting the second diagonal, The image sensor has a rectangular imaging surface. The lens has a rectangular shape for both the light incident surface and the back surface, and a rectangular prism extending from the light incident surface to the back surface. Endoscope.

2. An image sensor having an imaging surface and an element cover glass covering the imaging surface, The element is bonded to the cover glass by an adhesive and comprises a lens that forms an image of light on the image sensor, The aforementioned lens is, The light incident surface of the aforementioned lens extends in a direction perpendicular to the optical axis direction, The back surface is parallel to the light incident surface and faces the element cover glass, The lens has an opening located on the back surface and an internal lens space located between the opening and the light incident surface, and a recess that is recessed from the opening toward the light incident surface, An emission unit is arranged in the lens's internal space and emits light from the light incident surface to the imaging surface, A frame portion is arranged around the opening on the rear surface, It has a projection that protrudes from the frame portion in the direction of the optical axis and contacts the element cover glass, The aforementioned projection is A first projection is positioned at the first corner of the frame portion that intersects with the first diagonal of the back surface, A second projection is positioned at the second corner of the frame portion intersecting the first diagonal, A third projection is positioned at the third corner of the frame portion that intersects with the second diagonal of the back surface which intersects with the first diagonal, It has a fourth projection positioned at the fourth corner of the frame portion intersecting the second diagonal, The image sensor has a rectangular imaging surface. The lens has a rectangular shape for both the light incident surface and the back surface, and a rectangular prism extending from the light incident surface to the back surface. Endoscope.

3. The emission portion has a top portion that is positioned between the back surface and the light incident surface with respect to the optical axis, The endoscope according to claim 1 or 2.

4. The emission portion has a convex curved surface portion that rises in a first direction toward the back surface from the light incident surface with respect to the optical axis, The aforementioned top portion is located on the convex curved surface portion. The endoscope according to claim 3.

5. The aforementioned recess is It has a bottom surface that is located between the back surface and the light incident surface in the optical axis direction and is positioned closer to the light incident surface than the top surface, The aforementioned convex curved surface portion is A protrusion extending from the bottom surface in the first direction, The endoscope according to claim 4.

6. The aforementioned convex curved surface is a sphere. The endoscope according to claim 5.

7. The first projection, the second projection, the third projection, and the fourth projection are The shape, when viewed in the first direction from the back surface toward the light incident surface with respect to the optical axis, is fan-shaped. The endoscope according to claim 1 or 2.

8. The aforementioned frame portion is This is a frame-shaped end surface that is arranged on the same plane as the aforementioned back surface. The endoscope according to claim 1 or 2.

9. An image sensor having an imaging surface, A method for manufacturing an endoscope comprising a frame portion disposed on the back surface facing the imaging surface, and a lens having a projection portion disposed on the frame portion, which is bonded to the imaging surface by an adhesive and forms an image on the image sensor, A coating step of applying adhesive to either the frame portion or the imaging surface, An optical axis alignment step of aligning the optical axis of the image sensor with the optical axis of the lens, A contact step in which the lens and the imaging surface are brought into contact via the aforementioned projection, The process includes a curing step for curing the adhesive, The aforementioned lens is, The light incident surface of the aforementioned lens extends in a direction perpendicular to the optical axis direction, A back surface that is parallel to the light incident surface and faces the imaging surface, The lens has an opening located on the back surface and an internal lens space located between the opening and the light incident surface, and a recess that is recessed from the opening toward the light incident surface, An emission unit is arranged in the lens's internal space and emits light from the light incident surface to the imaging surface, A frame portion is arranged around the opening on the rear surface, It has a projection that protrudes from the frame portion in the direction of the optical axis and contacts the imaging surface, The aforementioned projection is A first projection is positioned at the first corner of the frame portion that intersects with the first diagonal of the back surface, A second projection is positioned at the second corner of the frame portion intersecting the first diagonal, A third projection is positioned at the third corner of the frame portion that intersects with the second diagonal of the back surface which intersects with the first diagonal, It has a fourth projection positioned at the fourth corner of the frame portion intersecting the second diagonal, The image sensor has a rectangular imaging surface. The lens has a rectangular shape for both the light incident surface and the back surface, and a rectangular prism extending from the light incident surface to the back surface. Endoscope manufacturing method.

10. An image sensor having an imaging surface and an element cover glass covering the imaging surface, A method for manufacturing an endoscope comprising a frame portion disposed on the back surface facing the element cover glass, and a projection portion disposed on the frame portion, which is bonded to the element cover glass with an adhesive and forms an image of light on the image sensor, A coating step of applying adhesive to either the frame portion or the element cover glass, An optical axis alignment step of aligning the optical axis of the image sensor with the optical axis of the lens, A contact step in which the lens and the element cover glass are brought into contact via the projection, The process includes a curing step for curing the adhesive, The aforementioned lens is, The light incident surface of the aforementioned lens extends in a direction perpendicular to the optical axis direction, The back surface is parallel to the light incident surface and faces the element cover glass, The lens has an opening located on the back surface and an internal lens space located between the opening and the light incident surface, and a recess that is recessed from the opening toward the light incident surface, An emission unit is arranged in the lens's internal space and emits light from the light incident surface to the imaging surface, A frame portion is arranged around the opening on the rear surface, It has a projection that protrudes from the frame portion in the direction of the optical axis and contacts the element cover glass, The aforementioned projection is A first projection is positioned at the first corner of the frame portion that intersects with the first diagonal of the back surface, A second projection is positioned at the second corner of the frame portion intersecting the first diagonal, A third projection is positioned at the third corner of the frame portion that intersects with the second diagonal of the back surface which intersects with the first diagonal, It has a fourth projection positioned at the fourth corner of the frame portion intersecting the second diagonal, The image sensor has a rectangular imaging surface. The lens has a rectangular shape for both the light incident surface and the back surface, and a rectangular prism extending from the light incident surface to the back surface. Endoscope manufacturing method.

Images