Endoscopic imaging device and endoscope

Abstract

To provide an endoscope imaging device and an endoscope high in reliability that can easily form an underfill layer.SOLUTION: An endoscope imaging device for acquiring an image of an observation object includes a lens barrel in which an imaging lens is provided, an image pick-up device that receives the light passing through the imaging lens, and subjects it to photoelectric conversion, a circuit board to which the image pick-up device is electrically connected through a bump having conductivity, and an underfill layer provided between the image pick-up device and the circuit board. The circuit board is bent, and has a bent part on the side opposite to the lens barrel. When a distance between a rear end on a bent part side of the circuit board of the image pick-up device and the bent part of the circuit board is represented as L1, and a distance between a front end on a lens barrel side of the image pick-up device and the front end on the lens barrel side of the circuit board is represented as L2, an inequality of L1<L2 is satisfied.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an endoscope imaging apparatus and an endoscope for acquiring an image of an observation target.

Background Art

[0002] In recent years, diagnosis and the like using an endoscope system including an endoscope light source device, an endoscope (endoscope scope), and a processor device have been widely performed. It has an insertion portion to be inserted into the body of a subject, and illumination light from an endoscope light source device is irradiated onto an observation target through the insertion portion. The endoscope captures an observation target irradiated with illumination light by an image sensor to generate an image signal. The processor device performs image processing on the image signal generated by the endoscope to generate an observation image for display on a monitor. The image sensor is electrically connected to a signal cable via a flexible wiring board, and the signal cable is electrically connected to the processor device.

[0003] Regarding the endoscope, since the physical burden on the subject is small, it is required that the insertion portion inserted into the body of the subject be small. Furthermore, since the endoscope is inserted into the body of the subject, high reliability is also required. For example, in the imaging module of Patent Document 1, it has an image sensor, a chip size package in which a plurality of connection lands are arranged on the back surface side of the light receiving portion of the image sensor, a circuit board having a plurality of connection electrodes, and the connection electrodes are electrically and mechanically connected to the connection lands of the chip size package via bumps, and an underfill agent filled in the gap between the chip size package and the circuit board. The circuit board and the underfill agent are sized to fit within the projection plane in the optical axis direction of the chip size package, and at least a notch portion that opens to the connection surface is formed on a side surface of the circuit board orthogonal to the connection surface with the chip size package.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above Patent Document 1, a notch is provided to fill an underfill agent, but the underfill agent cannot always be supplied to a predetermined position. An object of the present invention is to provide an endoscope imaging device and an endoscope that can easily form an underfill layer and have high reliability.

Means for Solving the Problems

[0006] In order to achieve the above object, one aspect of the present invention is an endoscope imaging device that acquires an image of an observation target, including a lens barrel provided with an imaging lens inside, an imaging element that receives light passing through the imaging lens and performs photoelectric conversion, a circuit board to which the imaging element is electrically connected via a conductive bump, and an underfill layer provided between the imaging element and the circuit board. The circuit board is bent, and the circuit board has a bent portion on the opposite side of the lens barrel. When the distance between the rear end of the imaging element on the bent portion side of the circuit board and the bent portion of the circuit board is L1, and the distance between the front end of the imaging element on the lens barrel side and the front end of the circuit board on the lens barrel side is L2, L1 < L2. An endoscope imaging device is provided.

[0007] It has at least one glass member disposed between the lens barrel and the imaging element, and a holding member that connects the glass member and the lens barrel. The circuit board is disposed below the base portion of the holding member on the glass member side. The holding member has a flat surface at the base portion on the glass member side, which faces the circuit board. The circuit board has a notch at the front end on the lens barrel side, and it is preferable that the notch exposes the flat surface of the holding member. The circuit board preferably has a recess on the surface to which the imaging element is connected, and the recess is provided at an end portion on the front end side of the circuit board rather than the front end of the imaging element. It is preferable that a part of the recess is located below the imaging element. The device preferably includes an electronic component for driving the image sensor, a signal cable electrically connected to the image sensor, and a connecting member for holding the signal cable with respect to a holding member, wherein the electronic component and the signal cable are arranged on a circuit board, and the circuit board is bent in multiple bending regions. Furthermore, one aspect of the present invention provides an endoscope having the endoscopic imaging device of the present invention. [Effects of the Invention]

[0008] According to the present invention, an underfill layer can be easily formed, and a highly reliable endoscopic imaging device and endoscope can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing an example of an endoscopic system having an endoscope according to an embodiment of the present invention. [Figure 2] This is a schematic perspective view showing a first example of an endoscopic imaging device according to an embodiment of the present invention. [Figure 3] This is a schematic perspective view showing a connecting member of a first example of an endoscopic imaging device according to an embodiment of the present invention. [Figure 4] This is a schematic side view showing a first example of an endoscopic imaging device according to an embodiment of the present invention. [Figure 5] This is a schematic diagram showing a holding member and a circuit board of a first example of an endoscopic imaging device according to an embodiment of the present invention. [Figure 6] This is a schematic diagram showing the image sensor and a recess in the circuit board of a first example of an endoscopic imaging device according to an embodiment of the present invention. [Figure 7] This is a schematic side view showing an example of a circuit board of a first example of an endoscopic imaging device according to an embodiment of the present invention. [Figure 8] This is a schematic side view showing another example of a circuit board of a first example of an endoscopic imaging device according to an embodiment of the present invention. [Figure 9] This is a schematic plan view showing another example of a circuit board of a first example of an endoscopic imaging device according to an embodiment of the present invention. [Figure 10]It is a schematic side view showing another example of a circuit board of a first example of an endoscope imaging apparatus according to an embodiment of the present invention. [Figure 11] It is a schematic perspective view showing a second example of an endoscope imaging apparatus according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, based on the preferred embodiments shown in the accompanying drawings, the endoscope imaging apparatus and endoscope of the present invention will be described in detail. Note that the drawings described below are illustrative for explaining the present invention, and the present invention is not limited to the drawings shown below. Orthogonality, parallelism, etc. in the following description include the error ranges generally allowed in the relevant technical field. Also, the numerical values of the thermal conductivity include the error ranges generally allowed in the relevant technical field.

[0011] 〔Endoscope System〕 The endoscope system irradiates illumination light (not shown) on an observation site such as inside the body of a subject who is the observation target, captures an image of the observation site, generates a display image of the observation site based on the image signal obtained by the imaging, and displays the display image. FIG. 1 is a schematic diagram showing an example of an endoscope system having an endoscope according to an embodiment of the present invention. The endoscope system 10 includes an endoscope 12, a light source device 14, and a processor device 16. The endoscope system 10 has the same configuration as a general endoscope except for the part of the endoscope imaging apparatus (camera head) of the endoscope 12 described later.

[0012] The endoscope 12 has an endoscope imaging apparatus. Further, although not shown in detail, the endoscope 12 has an insertion portion inserted into the subject, an operation portion connected to the insertion portion, and a universal cord extending from the operation portion. The insertion portion is composed of a distal end portion, a bending portion connected to the distal end portion, and a flexible portion connecting the bending portion and the operation portion. The endoscope imaging apparatus will be described later.

[0013] At the tip of the endoscope 12, an endoscope imaging device 20 (see Fig. 2) having an illumination optical system that emits illumination light for illuminating the observation site, or an imaging element and an imaging optical system that image the observation site, etc. is provided. The bending section is configured to be bendable in a direction orthogonal to the longitudinal axis of the insertion section, and the bending operation of the bending section is operated by the operation section. Further, the flexible section is configured to be relatively flexible so as to be deformable following the shape of the insertion path of the insertion section.

[0014] The operation section is provided with a button for operating the imaging operation of the endoscope imaging device 20 (see Fig. 2) at the tip, or a knob for operating the bending operation of the bending section, etc. Further, the operation section is provided with an introduction port into which a treatment tool such as an electric scalpel is introduced, and inside the insertion section, a treatment tool channel that reaches the tip from the introduction port and through which a treatment tool such as forceps is inserted is provided.

[0015] A connector is provided at the end of the universal cord, and the endoscope 12 is connected via the connector to a light source device 14 that generates illumination light emitted from the illumination optical system at the tip, and a processor device 16 that processes the video signal acquired by the endoscope imaging device 20 (see Fig. 2) at the tip.

[0016] The processor device 16 processes the input video signal to generate video data of the observation site, and displays the generated video data on a monitor (not shown) or records it on a storage medium such as a hard disk. Note that the processor device 16 may be configured by a processor such as a personal computer.

[0017] The light source device 14 generates white light composed of three primary colors of light such as red light (R), green light (G), and blue light (B) or illumination light such as light of a specific wavelength in order to image the observation target site in the body cavity by the endoscope imaging device 20 (see Fig. 2) of the endoscope 12, acquire an image signal of the observation target, supply it to the endoscope 12, propagate it through a light guide or the like inside the endoscope 12, and emit it from the illumination optical system at the tip of the insertion section of the endoscope 12 to illuminate the observation target site in the body cavity.

[0018] A light guide or a group of wires (signal cables) is housed inside the insertion section, the operating section, and the universal cord. Illumination light generated by the light source device 14 is guided to the illumination optical system at the tip via the light guide, and at least one of the signals and power is transmitted between the endoscope imaging device 20 (see Figure 2) at the tip and the processor device 16 via the group of wires.

[0019] Furthermore, the endoscope system 10 may also include a water supply tank for storing cleaning water, a suction pump for aspirating material from the body cavity (including the supplied cleaning water). In addition, it may also include a supply pump for supplying cleaning water from the water supply tank or gas such as outside air to the tubing (not shown) inside the endoscope.

[0020] [First example of an endoscopic imaging device] Figure 2 is a schematic perspective view showing a first example of an endoscopic imaging device according to an embodiment of the present invention, Figure 3 is a schematic side view showing a connecting member of the first example of an endoscopic imaging device according to an embodiment of the present invention, and Figure 4 is a schematic side view showing a first example of an endoscopic imaging device according to an embodiment of the present invention. Note that Figure 4 shows the state with the connecting member 30 of Figure 3 removed. The endoscopic imaging device 20 shown in Figure 2 is mounted on the tip of the endoscope 12 of the endoscopic system 10 shown in Figure 1. The endoscopic imaging device 20 acquires images of the object being observed and, for example, as shown in Figure 2, includes a lens barrel 22, a holding member 24, an image sensor 25, a circuit board 26 on which the image sensor 25 and electronic components 36 and 36a are arranged, and a connecting member 30 that holds a signal cable 28 to the holding member 24. As shown in Figure 4, the image sensor 25 is electrically connected to the circuit board 26 via conductive bumps 42. It also has an underfill layer 44 provided between the image sensor 25 and the circuit board 26. The electronic components 36 and 36a are electrically connected to the circuit board 26. Furthermore, the endoscopic imaging device 20 has an engaging portion 32 that engages with a holding member 24 and a connecting member 30.

[0021] The signal cable 28 is electrically connected to the image sensor 25, and the image sensor 25 is electrically connected to the processor device 16 (see Figure 1) via the circuit board 26 and the signal cable 28. The signal cable 28 is placed within the universal cord. The configuration of the signal cable 28 is not particularly limited. The signal cable 28 is a multi-core cable in which a large number of signal lines 29 are bundled together, a shield conductor is provided around them, and the cable is housed in a cylindrical outer sheath, as shown in Figure 4, for example. The shield conductor of the signal cable 28 is called the shield 28a. The signal line 29 has, for example, four lines. The number of signal lines is not particularly limited and may be two, three, or five or more.

[0022] The lens barrel 22 is a cylindrical component, and an imaging lens 23 for imaging the object to be observed is provided inside. The configuration of the imaging lens 23 is not particularly limited; it may have a configuration with multiple lenses arranged in parallel in the optical axis C direction, or it may have a configuration with a single lens. Here, as shown in Figures 2 and 4, the direction parallel to the optical axis C is defined as the X direction. Of the two directions perpendicular to the optical axis C, one is defined as the Y direction and the other as the Z direction. The Y direction corresponds to the width direction of the endoscope imaging device 20, and the Z direction corresponds to the height direction of the endoscope imaging device 20.

[0023] The retaining member 24 has a cylindrical mounting tube portion 24a fitted to the outer circumference of the lens barrel 22, and a base portion 24b integrally provided continuous with the mounting tube portion 24a. A prism 34 is provided on the back surface 24e of the base portion 24b. The retaining member 24 connects the glass member such as the prism 34 to the lens barrel 22. The prism 34 is, for example, a right-angle prism where the incident surface 34a and the exit surface 34b are perpendicular to each other. The incident surface 34a is positioned toward the back surface 24e of the base 24b. As a result, the incident surface 34a faces the imaging lens 23. A cover glass 33 is placed on the image sensor 25. A prism 34 is placed on the cover glass 33, and the emission surface 34b of the prism 34 faces the image sensor 25. The cover glass 33 protects the light-receiving surface (not shown) of the image sensor 25. The prism 34 guides the light that has passed through the imaging lens 23 to the light-receiving surface of the image sensor 25.

[0024] The image sensor 25 is provided, for example, on the surface 26a of one end of the circuit board 26, parallel to the optical axis C of the imaging lens 23, and is positioned below the base 24b of the holding member 24. On the back surface 26b of the circuit board 26 opposite to the light-receiving surface of the image sensor 25, there are a number of connection terminals (not shown) to which signals or power are input and output to the image sensor 25 and electronic components 36, 36a.

[0025] The circuit board 26 is made of, for example, a flexible substrate. The flexible substrate is, for example, a flexible wiring board. The circuit board 26 is bent in two places, as shown in Figure 4, and has a first curved portion 26c and a second curved portion 26d. Between the first curved portion 26c and the second curved portion 26d, for example, two electronic components 36 are provided on the surface 26a of the circuit board 26. On the surface 26a of the circuit board 26 that is continuous with the second curved portion 26d, for example, three electronic components 36 and two electronic components 36a are provided.

[0026] By bending the circuit board 26 in two places to create a first curved portion 26c and a second curved portion 26d, it can be made smaller in the X direction, and the endoscopic imaging device 20 can be miniaturized in the X direction. In other words, the endoscopic imaging device 20 can be shortened. As shown in Figure 4, the signal lines 29 of the signal cable 28 are electrically connected to a connection terminal (not shown) provided on the back surface 26b of the other end of the circuit board 26. Furthermore, the bending of the circuit board 26 is not limited to two locations, but is determined as appropriate depending on the device configuration, such as the number of electronic components 36 and 36a, or the size of the device.

[0027] The image sensor 25 receives light that has passed through the imaging lens 23 and converts it into photoelectric light. The image sensor 25 obtains an imaging signal by photoelectrically converting the optical image of the object being observed. As described above, the image sensor 25 is electrically connected to the circuit board 26 via conductive bumps 42, and an underfill layer 44 is filled between the image sensor 25 and the circuit board 26. The underfill layer 44 is formed using an underfill material and strengthens the connection between the image sensor 25 and the circuit board 26. Furthermore, the underfill layer 44 alleviates stress that occurs at the joint between the image sensor 25 and the circuit board 26, such as the bump 42, due to the difference in thermal expansion coefficients between the two. The underfill layer 44 provides a strong connection between the image sensor 25 and the circuit board 26, increasing the reliability of the electrical connection and resulting in a highly reliable endoscopic imaging device 20.

[0028] The conductive bump 42 is connected to an electrode provided on the connection surface of the image sensor 25 to the circuit board 26. The bump 42 is electrically connected to the wiring layer of the circuit board 26. The bump 42 is made of metal or an alloy. More specifically, the bump 42 is made of solder. A bump 42 formed of solder is also called a solder ball. However, the bump 42 is not limited to solder, as long as it can electrically connect the image sensor 25 and the circuit board 26. The bump 42 and the circuit board 26 may be electrically connected directly, or they may be electrically connected via a solder ball.

[0029] In the endoscopic imaging device 20, at least one glass component is placed between the lens barrel 22 and the image sensor 25. The at least one glass component is, for example, the cover glass 33 and the prism 34 described above, but the at least one glass component is not particularly limited to the cover glass 33 and the prism 34 described above.

[0030] The engaging portion 32 has at least one protrusion on the holding member 24 and a recess on the connecting member 30 that engages with the protrusion on the holding member 24. The engaging portion 32 enables firm fixing of the holding member 24 and the connecting member 30 by the engagement of the protrusion on the holding member 24 and the recess on the connecting member 30. The recess on the connecting member 30 also includes a through-opening, which will be described later.

[0031] The base 24b of the retaining member 24 shown in Figures 2 and 4 has two protrusions 24c that face each other and sandwich the prism 34. The two protrusions 24c cover a portion of the side surface 34c of the prism 34, and the prism 34 is held in place by the two protrusions 24c. The two protrusions 24c are the same shape and size, and are provided on both sides of the base 24b of the retaining member 24. The side surface 34c of the prism 34 is perpendicular to the incident surface 34a and the exit surface 34b. In the retaining member 24, the protrusion 24c of the base 24b (see Figures 2 and 4) is, for example, rectangular in shape, but one corner is cut out. Therefore, the protrusion 24c of the base 24b (see Figures 2 and 4) is essentially a pentagon.

[0032] The connecting member 30 holds the signal cable 28 in place of the holding member 24. The connecting member 30, for example as shown in Figure 3, has a flat bottom portion 40f formed by bending a single plate, and a holding portion 40a having a flat base portion 40g continuous with the bottom portion 40f. In the connecting member 30, the side with the holding portion 40a is the base end 41a. When the base portion 40g is crimped to press against the signal cable 28, the base portion 40g is bent along the outer sheath of the signal cable 28. In the holding portion 40a, an arm portion 40b is provided on each of the flat base portion 40g that are opposite each other across the opening. The connecting member 30 has a pair of arm portions 40b. The arm portions 40b are bent outward from the holding portion 40a at the base end 41a and then extend in a straight line. Therefore, the pair of arm portions 40b are spaced further apart at the tip 41b than at the base end 41a, and this spacing is appropriately determined to match the protrusion 24c of the holding member 24 shown in Figure 2. In addition, each arm portion 40b is provided with an opening 40c at its tip 41b.

[0033] The opening 40c of the arm portion 40b engages with the protrusion 24c of the holding member 24. The opening 40c is formed, for example, by cutting out a rectangular shape from a part of the arm portion 40b. Furthermore, the opening 40c may have the same size and shape as the outer shape of the protrusion 24c. Here, the shape of the opening 40c having the same size and shape as the outer shape of the protrusion 24c includes a tolerance range that is generally acceptable in the relevant art. For this reason, the opening 40c and the protrusion 24c may be a so-called clearance fit, intermediate fit, or interference fit. Furthermore, in the following explanation, "same size and shape" includes the generally acceptable margin of error in the relevant technical field, as mentioned above.

[0034] As described above, the configuration has an engaging portion 32 that engages the opening 40c of a pair of arm portions 40b with the protrusion 24c of the holding member 24. Because the recess fits into the protrusion, the length of the endoscopic imaging device 20 in the Y direction perpendicular to the optical axis C can be shortened, thereby suppressing an increase in the size of the endoscopic imaging device 20. Moreover, a firm fixation between the holding member 24 and the connecting member 30 can be achieved. Furthermore, by matching the thickness of the arm portion 40b with the height of the protrusion 24c, when the openings 40c of a pair of arm portions 40b engage with the protrusions 24c of the holding member 24, the length of the endoscopic imaging device 20 in the Y direction perpendicular to the optical axis C can be shortened, and this configuration allows for a more compact endoscopic imaging device 20.

[0035] In the connecting member 30, it is preferable that the pair of arm portions 40b are bent such that their tip ends 41b are closer to each other than their base ends 41a. That is, it is preferable that the pair of arm portions 40b are bent in a closing direction. This allows the opening 40c of the arm portion 40b to be fitted into the protrusion 24c of the holding member 24 by spreading the arm portion 40b once, making assembly easy. As described above, it is preferable that the pair of arm portions 40b are bent such that their tip ends 41b are closer to each other than their base ends 41a, but this may be the state of the parts before assembly. Furthermore, although the arm portion 40b is provided with a through-hole 40c, it is not limited to this, and a recess with a bottom that is only a recess without a through-hole is also acceptable. The connecting member 30 is held by the signal cable 28 being attached to the inside 40e of the holding portion 40a. The method of attaching the signal cable 28 is not particularly limited, as long as the signal cable 28 does not come off the holding portion 40a and the signal wire 29 does not come off when the endoscope is in use. For example, it can be attached to the connecting member 30 using adhesive.

[0036] In addition, the two protrusions 24c of the holding member 24 are the same in size and shape as described above, i.e., congruent, but they may be different in size and shape. Furthermore, the shape of the protrusion in the retaining member 24 is not particularly limited to the rectangle described above, but may be a circle, an ellipse, or a polygon such as a triangle, pentagon, or hexagon, or a shape formed by combining these shapes. Moreover, it may not be just one shape, but multiple identical shapes arranged together, or a specific pattern. In the engaging portion 32, one protrusion and one recess engage at one location, but the number of engaging locations is not limited to one; a configuration in which one protrusion has multiple engaging locations is also possible.

[0037] Furthermore, it is preferable that the size of the protrusion of the holding member 24 is such that it covers at least a portion of the side surface 34c of the prism 34. By making the size of the protrusion such that it covers at least a portion of the side surface 34c of the prism 34, the prism 34 can be held and fixed more stably, and it can also be used to position the prism in the Y direction relative to the holding member during assembly. The upper limit of the size of the protrusion of the holding member 24 can be set to a size that completely covers the side surface 34c of the prism 34. Furthermore, by providing two opposing protrusions 24c on the holding member 24, the prism 34 and the circuit board 26 are surrounded by the arm portion 40b. This stabilizes the engagement between the holding member 24 and the connecting member 30 and also protects the prism 34 and the circuit board 26. In the retaining member 24, two protrusions 24c are provided, but this configuration is not limited to this, as long as the size is not increased, three or more protrusions may be provided. In other words, the number of engaging parts can be three or more.

[0038] The prism 34 guides the light from the imaging lens 23 to the image sensor 25. It is not limited to a right-angle prism, and the shape of the prism 34 can be appropriately chosen depending on the position of the image sensor 25. In fact, the prism 34 is not always necessary depending on the position of the image sensor 25.

[0039] As the image sensor 25, a CCD (Charge Coupled Device) type image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor can be used. For example, by using a prism 34 that bends the optical axis C of the imaging lens 23 at a right angle, the degree of freedom in the placement position of the image sensor 25 can be increased, and a large image sensor 25 can be used without being limited by the size of the base 24b of the holding member 24. After the holding member 24 and the prism 34 are adhesively fixed, they are sandwiched from the side by the arm portion 40b, and the arm portion 40b, the holding member 24, and the prism 34 are adhesively connected. The joining of the holding member 24 and the prism 34 is also strengthened by adhering the arm portion 40b from the side. Further, by adhering not only the side surface of the holding member 24 but also the side surface 34c of the prism 34 and the arm portion 40b, the fixing strength of the arm portion 40b is also increased. The connection strength between the holding member 24 and the arm portion 40b is such that the convex portion 24c and the opening portion 40c (concave portion) have the same shape and the same size, and since the forces in the X direction and the Z direction are received by the cross-section of the arm portion, the mechanical strength of the endoscope imaging device 20 is increased.

[0040] FIG. 5 is a schematic diagram showing a holding member and a circuit board of a first example of an endoscope imaging device according to an embodiment of the present invention, and FIG. 6 is a schematic diagram showing an imaging element and a concave portion of a circuit board of a first example of an endoscope imaging device according to an embodiment of the present invention. In FIGS. 5 and 6, the same components as those of the endoscope imaging device 20 shown in FIGS. 2 to 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

[0041] [[ID=,10]]In the endoscope imaging device 20, as shown in FIG. 4, the distance between the rear end 25b on the bent portion 26e side of the circuit board 26 of the imaging element 25 and the bent portion 26e of the circuit board 26 is denoted as L1. The distance between the front end 25a on the lens barrel 22 side of the imaging element 25 and the front end 26f on the lens barrel 22 side of the circuit board 26 is denoted as L2. At this time, L1 < L2. In the circuit board 26, by setting L1 < L2, without increasing the length of the circuit board 26 below the imaging element 25, that is, without increasing the size of the endoscope imaging device 20, an underfill agent (not shown) that becomes the underfill layer 44 can be easily injected between the imaging element 25 and the circuit board 26 from the front end 26f side of the circuit board 26. Thereby, the underfill layer 44 can be easily formed between the imaging element 25 and the circuit board 26. Note that L1 is, for example, 0.35 mm, and L2 is, for example, 0.7 mm.

[0042] The underfill layer 44 is in a state where the underfill agent is cured. However, the underfill layer 44 may contain an uncured underfill agent. The underfill agent constituting the underfill layer 44 is not particularly limited, and those used as a sealing resin between an imaging device 25 such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor and a circuit board 26 can be appropriately used. For example, a one-component heat-curable epoxy resin is used as the underfill agent. In this case, after supplying the underfill agent, it is heated and held at a predetermined temperature to form the underfill layer 44. Although L1 < L2, it is preferable that L1 is as short as possible. Thereby, the length of the circuit board 26 below the imaging device 25 can be made longer without increasing, that is, L2 can be made even longer. That is, it is preferable because the endoscope imaging device 20 can be miniaturized, the underfill agent can be easily injected, and the underfill layer 44 can be more easily formed.

[0043] The bent portion 26e is the end on the side of the first curved portion 26c and is the start of the bend of the first curved portion 26c of the circuit board 26. The endoscope imaging device 20 is photographed using X-rays to obtain a cross-sectional image of the circuit board 26. In the cross-sectional image of the circuit board 26, the position where the first curved portion 26c of the circuit board 26 starts to bend can be specified, and the above-described bent portion 26e can be specified. The starting position of the bend is the connection position between the first curved portion 26c and the circuit board 26 below the imaging device 25. Therefore, by specifying the first curved portion 26c and assuming that the circuit board 26 is flat, the above-described connection position can be specified.

[0044] FIG. 5 shows a state of the endoscope imaging device 20 viewed from the back surface 26b side of the circuit board 26. As shown in Figure 5, the circuit board 26 is positioned below the base 24b on the glass member side of the holding member 24, that is, below the base 24b on the prism 34 side. The holding member 24 has a flat surface 24f on the glass member side, that is, on the base 24b on the prism 34 side, in the portion facing the circuit board 26. The circuit board 26 has a notch 26h at its tip on the lens barrel 22 side. The notch 26h is formed symmetrically with respect to the X direction, starting from the Y-direction end of the circuit board 26, leaving the tip 26f of the circuit board 26 intact. The Y-direction corner of the notch 26h on the Y-direction side of the circuit board 26 is arc-shaped. When viewed from the back surface 26b of the circuit board 26, the notch 26h exposes the flat surface 24f of the retaining member 24. For example, the flat surface 24f of the base 24b of the retaining member 24 contacts other members to restrict the rotation of the endoscope imaging device 20. The exposure of the flat surface 24f makes it easier to restrict rotation. Furthermore, the shape of the notch 26h is not particularly limited to the arc-shaped corner shown in Figure 5, as long as the plane 24f can be exposed.

[0045] Furthermore, as shown in Figure 6, the circuit board 26 has a recess 46 on the surface 26a to which the image sensor 25 is connected, and it is preferable that the recess 46 is provided at the end 26g of the circuit board 26 that is on the front end 26f side of the image sensor 25's front end 25a. Also, for example, the entire area of ​​the recess 46 is located at the end 26g of the circuit board 26 that is on the front end 26f side of the image sensor 25's front end 25a. The recess 46 holds the underfill material for forming the underfill layer 44. The recess 46 acts as a reservoir for the underfill material, preventing it from leaking out of the circuit board 26. The recess 46 allows for efficient supply of the underfill material between the image sensor 25 and the circuit board 26. After the underfill material is supplied to the recess 46, it is supplied between the image sensor 25 and the circuit board 26 by capillary action. Subsequently, for example, the underfill material is held at a temperature appropriate to it, and the underfill material hardens to form the underfill layer 44. By providing the recess 46, it becomes easier to supply the underfill material between the image sensor 25 and the circuit board 26.

[0046] Furthermore, it is more preferable that a portion of the recess 46 is located below the image sensor 25. That is, it is preferable that a portion of the recess 46 is submerged beneath the image sensor 25. By having a portion of the recess 46 located below the image sensor 25, when underfill material is supplied to the recess 46, the underfill material can be supplied more easily between the image sensor 25 and the circuit board 26. Furthermore, if the entire recess 46 is located below the image sensor 25, it becomes difficult to supply the underfill material to the recess 46. Therefore, it is preferable that a portion of the recess 46 is located on the front end 26f side of the circuit board 26 rather than the front end 25a of the image sensor 25. The recess 46 is formed by physically indenting the surface 26a of the circuit board 26 by pressing it. Alternatively, the recess 46 can be formed by removing a portion of the surface 26a of the circuit board 26. If the surface 26a of the circuit board 26 is composed of a resist layer (not shown), the recess 46 can be formed by removing the resist layer in the area where the recess 46 is formed. For example, as shown in Figure 6, the shape of the recess 46 when viewed from the surface 26a side of the circuit board 26 is circular, but the shape of the recess 46 is not limited to a circle and may be a polygon. The recess 46 is preferably circular in shape when viewed from the surface 26a side of the circuit board 26, and preferably has a diameter of 0.5 mm and a depth of 0.02 mm. If the size of the recess 46 is 0.5 mm in diameter and 0.02 mm in depth, the underfill material can be easily supplied between the image sensor 25 and the circuit board 26 after it has been supplied to the recess 46. The size of the recess 46 can be measured using an optical microscope or a laser microscope. Furthermore, the shape of the recess 46 can be determined using an optical microscope or a laser microscope.

[0047] <Example of a circuit board> Next, the circuit board 26 will be described. Figure 7 is a schematic side view showing an example of a circuit board of a first example of an endoscopic imaging device according to an embodiment of the present invention. Note that the circuit board 26 shown in Figure 7 is shown in its state before being folded into the form shown in Figure 2, and the unfolded state of the circuit board 26 is shown. As shown in Figure 7, for example, the circuit board 26 has an image sensor 25 and electronic components 36 arranged in predetermined positions on its surface 26a. The signal lines 29 of the signal cable 28 are electrically connected to connection terminals (not shown) provided on the back surface 26b. When the circuit board 26 is unfolded, that is, in its state before folding, the signal cable 28 extends to the opposite side from where the image sensor 25 is located. This configuration improves the workability when electrically connecting the signal cable 28 to the circuit board 26 with solder or the like, and also improves assembly workability.

[0048] In Figure 7, on the surface 26a of the circuit board 26, for example, an image sensor 25 and two electronic components 36 are provided with a first bending region 27a, and the two electronic components 36 and three electronic components 36, 36a, 36a on the signal cable 28 side are provided with a second bending region 27b. The first bending region 27a corresponds to the first curved portion 26c, and the second bending region 27b corresponds to the second curved portion 26d. In the circuit board 26, the first bending region 27a is bent so that the image sensor 25 and the electronic component 36 face each other, and the second bending region 27b is bent so that the back surfaces 26b of the circuit board 26 face each other. As a result, the circuit board 26 has a configuration having a first curved portion 26c and a second curved portion 26d, as shown in Figure 4. When bending the first bending region 27a, it is bent based on the first bent surface Lb1. When bending the second bending region 27b, it is bent based on the second bent surface Lb2. In this way, the circuit board 26 is bent at multiple bending regions. In Figure 7, the first bent surface Lb1 and the second bent surface Lb2 are parallel, but are not limited to this, and do not have to be parallel. Furthermore, since the first bent surface Lb1 is provided in the first bending region 27a and the second bent surface Lb2 is provided in the second bending region 27b, the first bent surface Lb1 and the second bent surface Lb2 are not orthogonal to each other. It is preferable that all the circuit boards 26 are bent in the same direction. This eliminates the bending region in the Y direction of the endoscopic imaging device 20, as seen in the first curved portion 26c and the second curved portion 26d, thereby reducing the proportion of the internal space of the endoscopic imaging device 20 occupied by the bending region.

[0049] Although the image sensor 25 and electronic components 36 and 36a are provided on the surface 26a of the circuit board 26, the design is not limited to this, and the image sensor 25 and electronic components 36 and 36a may be provided on separate surfaces. Furthermore, it is preferable to mount the image sensor 25 and the electronic components 36 and 36a on a single circuit board 26, as shown in Figure 7. By mounting them on a single circuit board 26, the number of components can be reduced. Electronic components 36 and 36a are for driving the image sensor 25 and are not particularly limited, but examples include voltage regulators, resistors, and capacitors. The voltage regulator is a device that stabilizes the voltage to the image sensor 25 and outputs a constant voltage to the image sensor 25. Furthermore, on the circuit board 26, for example, the back surface 26b of the circuit board 26 and the shield 28a of the signal cable 28 may be joined at the other end, for example, by soldering. By joining the shield 28a of the signal cable 28 to the back surface 26b, the heat generated from the image sensor 25 and electronic components 36 can be dissipated from the circuit board 26 through the signal cable 28 to the outside of the endoscopic imaging device 20, thereby improving the heat dissipation performance of the endoscopic imaging device 20.

[0050] <Other examples of circuit boards> Figure 8 is a schematic side view showing another example of the circuit board of the first example of the endoscopic imaging device according to an embodiment of the present invention, Figure 9 is a schematic top view showing another example of the circuit board of the first example of the endoscopic imaging device according to an embodiment of the present invention, and Figure 10 is a schematic side view showing another example of the circuit board of the first example of the endoscopic imaging device according to an embodiment of the present invention. In Figures 8 to 10, the same reference numerals are used for components identical to those in the endoscopic imaging device 20 shown in Figures 2 to 5 and the circuit board 26 shown in Figure 7, and their detailed descriptions are omitted. Figure 8 shows the circuit board 26 bent in two places, similar to Figure 4, and the underfill layer 44 is formed. Figures 9 and 10 show the circuit board 26 before bending, and Figure 10 shows the circuit board 26 in its unfolded state. The circuit board 26 shown in Figure 10 bends based on the first bend surface Lb1 when bending the first bending region 27a, similar to the circuit board 26 shown in Figure 7. When bending the second bending region 27b, it bends based on the second bend surface Lb2.

[0051] As shown in Figure 8, in a configuration in which the circuit board 26 is bent at two locations, a first bending region 27a and a second bending region 27b, similar to Figure 7, if the first curved portion 26c and the second curved portion 26d cannot be bent at a predetermined radius of curvature, for example, the circuit board 26 near the first curved portion 26c and near the second curved portion 36d will not be flat. In this case, the connection state of the electronic component 36b near the first curved portion 26c and the electronic component 36c near the second curved portion 26d will be affected, and for example, poor connection of the electronic components 36b and 36c may occur.

[0052] As shown in Figures 9 and 10, the circuit board 26 is configured to have a thin-walled portion 48 in the first bending region 27a and a thin-walled portion 49 in the second bending region 27b. By providing the circuit board 26 with the aforementioned thin-walled portions 48 and 49, the first bending region 27a and the second bending region 27b become easier to bend, and the first curved portion 26c and the second curved portion 26d can be more reliably made to a predetermined radius of curvature. As a result, the connection state of the electronic components 36b near the first curved portion 26c and the electronic components 36c near the second curved portion 26d is not affected, and the connection state of the electronic components 36b and 36c can be improved. The thin-walled portions 48 and 49 described above are formed, for example, by thinning the circuit board 26 itself. More specifically, for example, if the circuit board 26 has a ground layer, the thin-walled portions 48 and 49 are formed by removing the resist layer formed on the ground layer. The sizes of the thin-walled portions 48 and 49 are appropriately determined according to the sizes of the first bending region 27a and the second bending region 27b, respectively. The thin-walled portion 48 may be formed over the entire area of ​​the first bending region 27a, or only in part of it. The end of the thin-walled portion 48 may be aligned with the bent portion 26e. Furthermore, the thin-walled portion 49 may be formed over the entire area or only in part, as long as it is within the second bending region 27b. The end of the thin-walled portion 49 may be aligned with the end of the bent portion.

[0053] [Second example of an endoscopic imaging device] The endoscopic imaging device 20 is not limited to the configuration shown in Figure 2. A second example of the endoscopic imaging device will be described below. Figure 11 is a schematic perspective view showing a second example of an endoscopic imaging device according to an embodiment of the present invention. In Figure 11, the same reference numerals are used for components identical to the endoscopic imaging device 20 shown in Figures 2 and 4, and the connecting member 30 shown in Figure 3, and their detailed descriptions are omitted.

[0054] The endoscopic imaging device 20a shown in Figure 11 differs from the endoscopic imaging device 20 shown in Figure 2 in that it has a cover 50, but all other configurations are the same as the endoscopic imaging device 20 shown in Figures 2 and 4. The endoscopic imaging device 20a has a cover 50 that covers the electronic components 36, 36a. Preferably, the cover 50 is made of metal, for example. By providing a metal cover 50, the heat generated by the electronic components 36, 36a is conducted to the cover 50, and the heat generated by the electronic components 36, 36a can be dissipated to the outside of the endoscopic imaging device 20a. The cover 50 is made of, for example, stainless steel, copper alloy, or graphite. Furthermore, it is preferable that the cover 50 is joined to the connecting member 30, or that the cover 50 and the connecting member 30 are integrally constructed. This increases the number of components to which the heat generated by the electronic components 36 and 36a conducts, further reducing the amount of heat that could be conducted to the image sensor 25, and also allows for efficient heat dissipation outside the endoscopic imaging device 20. Furthermore, if the cover 50 and the connecting member 30 are integrally constructed, the cover 50 and the connecting member 30 are made of the same metal. Furthermore, the cover 50 and the connecting member 30 may be separate components. In this case, it is preferable that the cover 50 holds the arm portion 40b of the connecting member 30 such that the tip 41b of the arm portion 40b is closer to the base end 41a than the tip 41b of the arm portion 40b. This makes it less likely for the opening 40c of the arm portion 40b and the protrusion 24c of the holding member 24 to come apart, and the holding member 24 and the connecting member 30 are more securely fixed, resulting in increased rigidity of the endoscopic imaging device 20a.

[0055] The present invention is basically configured as described above. Although the endoscopic imaging device and endoscope of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various improvements or modifications may be made without departing from the spirit of the present invention. [Explanation of Symbols]

[0056] 10 Endoscopy Systems 12 Endoscopes 14 Light source device 16 Processor Unit 20, 20a Endoscopic imaging device 22 Lens barrel 23 Imaging Lens 24 Retaining member 24a Mounting cylinder 24b base 24c convex part 24e Reverse side 24f plane 25 Image sensor 25a, 26f tip 25b rear end 26 Circuit boards 26a surface 26b Reverse side 26c First curved section 26d Second curved section 26e Bend part 26g end 26h Notch 27a First bending region 27b Second bending region 28 signal cables 28a Shield 29 Signal lines 30 Connecting member 32 Engaging part 33 Cover glass 34 Prisms 34a Entrance plane 34b Output surface 34c side 36, 36a Electronic components 40a Holding part 40b Arm section 40c opening 40e inside 40f bottom 40g base material part 41a proximal end 41b Tip 42 Bump 44 Underfill Layers 46 recess 48, 49 Thin-walled section 50 Covers C optical axis Lb1 First Fold Surface Lb2 Second Fold Surface

Claims

1. An endoscopic imaging device that acquires images of the object being observed, A lens barrel with an imaging lens inside, An image sensor that receives light that has passed through the aforementioned imaging lens and converts it into photoelectric light, The image sensor is electrically connected to a circuit board via conductive bumps, The image sensor and the circuit board are provided with an underfill layer filled between them. The circuit board is bent, and the circuit board has a bent portion on the opposite side of the lens barrel. The distance L is the distance between the rear end of the circuit board of the image sensor on the bent portion side and the starting position of the bend of the circuit board. １ The distance between the front end of the image sensor on the lens barrel side and the front end of the circuit board on the lens barrel side is L. ２ In that case, L １ <L ２ And, The circuit board has a recess on the surface to which the image sensor is connected, The recess is provided at the end of the circuit board closer to the tip than the tip of the image sensor, in an endoscopic imaging device.

2. At least one glass member is disposed between the lens barrel and the image sensor, It has a holding member that connects the glass member and the lens barrel, The circuit board is positioned below the base portion of the holding member on the glass member side. The holding member has a flat surface at the base on the glass member side, in the portion facing the circuit board. The endoscope imaging apparatus according to claim 1, wherein the circuit board has a notch at the tip on the lens barrel side, and the notch exposes the flat surface of the holding member.

3. The electronic component that drives the image sensor, A signal cable electrically connected to the image sensor, The holding member has a connecting member for holding the signal cable, The aforementioned electronic components and signal cables are arranged on the circuit board. The endoscopic imaging device according to claim 2, wherein the circuit board is bent in a plurality of bending regions.

4. An endoscope having an endoscopic imaging device according to any one of claims 1 to 3.

Images