JP7702341B2 - Endoscope imaging device and endoscope - Google Patents

Description

The present invention relates to an endoscopic imaging device and an endoscope that capture images of an object to be observed, and in particular to an endoscopic imaging device and an endoscope in which an imaging element is electrically connected to a circuit board, and a signal cable is electrically connected to the circuit board.

2. Description of the Related Art In recent years, diagnosis and the like using an endoscope system including an endoscope light source device, an endoscope (endoscopic scope), and a processor device has been widely performed.
The endoscope has an insertion portion that is inserted into the body of a subject, and illumination light from the endoscopic light source device is irradiated onto the observation object through the insertion portion. The endoscope uses an imaging element to capture an image of the observation object irradiated with the illumination light and generate an image signal. The processor device processes the image signal generated by the endoscope to generate an observation image to be displayed on a monitor. The imaging element is electrically connected to a signal cable via a circuit board formed of a flexible wiring board or the like, and the signal cable is electrically connected to the processor device.

For example, Patent Document 1 describes an endoscope having an imaging module. The imaging module includes an electric cable, an imaging element, and a flexible wiring board. The flexible wiring board has an element mounting section for mounting the imaging element, and a rear piece that is bent at a bending portion at only one of both ends in the length direction of the element mounting section and extends to the opposite side from the imaging element. The element mounting section has a mounting surface that intersects with the axial direction of the tip of the electric cable and that mounts the imaging element. The wiring of the flexible wiring board passes from the mounting surface through the bending portion and is connected to the electric cable at the rear piece. A conductor connection portion is formed in the rear piece. The conductor connection portion is formed by soldering an internal conductor to the conductor terminal portion.

For example, Patent Document 2 describes an endoscope having a scope with a rigid section at the tip of a long flexible section, and an imaging section housed in the rigid section and having an image sensor. A flexible substrate is conductively connected to the back of the image sensor via a pad. The flexible substrate is disposed between the image sensor and the transmission cable to relay between the two. For example, a circuit pattern is formed on the flexible substrate, in which a plurality of linear conductors are pattern-printed. The flexible substrate conductively connects each of the electric wires provided in the transmission cable to this circuit pattern. As a result, the image sensor is connected to the transmission cable via the flexible substrate. The flexible substrate is bent in an L shape with a sensor connection section parallel to the back of the image sensor and a cable connection section perpendicular to the back. The front of the sensor connection section of the flexible substrate is conductively connected to a pad provided on the back of the image sensor. The cable connection section has a plurality of terminal sections exposed on the upper surface, which are conductively connected to each of the electric wires of the transmission cable.

JP 2019-186619 A JP 2020-146280 A

When a signal cable is connected to a circuit board using solder or the like, the circuit board may become partially hard at the solder connection. In the endoscopes of the above-mentioned Patent Documents 1 and 2, an electric cable or a transmission cable is connected to a flexible wiring board or a flexible board by soldering. In this case, the partially hardened connection may cause the flexible wiring board or the flexible board to break or be damaged at the solder connection. This may cause wiring such as signal lines of the flexible wiring board or the flexible board to break.
An object of the present invention is to provide an endoscopic imaging device and an endoscope which prevent damage to and disconnection of a circuit board.

In order to achieve the above-mentioned object, one aspect of the present invention provides an endoscopic imaging device for acquiring an image of an observation target, the device comprising: a lens barrel having an imaging lens disposed therein; an imaging element for receiving light passing through the imaging lens and performing photoelectric conversion; a circuit board to which the imaging element is electrically connected; and a signal cable electrically connected to the circuit board, the circuit board having a connection pad on one side to which the signal cable is electrically connected; a metal layer on the other side opposite to the one side of the circuit board; and when the circuit board is viewed from the one side or the other side, the metal layer overlaps with the connection pad and is disposed over a larger area than the connection pad.

It is preferable that a signal line is provided on one surface of the circuit board, a connecting member is provided on the other surface of the circuit board, the imaging element is provided on the other surface electrically connected to the connecting member, and the connecting member is electrically connected to the signal line in an area of one surface opposite the other surface on which the imaging element is provided.
The circuit board has a side surface in a width direction perpendicular to the extending direction of the circuit board, the recessed portion being connected by a connecting portion, and the connecting portion is preferably located inside the circuit board relative to the side surface.
It is preferable that the circuit board has, in that order, a tip end portion where the imaging element is provided, a curved portion, an inclined portion, and a rear end portion where a connection pad is provided, and that electronic components that drive the imaging element are provided on one side of the circuit board at the inclined portion.
The optical axis of the imaging lens is preferably perpendicular to the light receiving surface of the imaging element.
It is preferable that the optical axis of the imaging lens is parallel to the light receiving surface of the imaging element.
The metal layer is preferably electrically connected to ground.
Another aspect of the present invention is to provide an endoscope having the endoscopic imaging device of the present invention.

The present invention provides an endoscopic imaging device and an endoscope that prevent damage to and disconnection of the circuit board.

1 is a schematic diagram showing an example of an endoscope system according to an embodiment of the present invention. 1 is a schematic perspective view showing an endoscopic imaging device according to an embodiment of the present invention. 1 is a schematic, partially cut-away perspective view showing an endoscopic imaging device according to an embodiment of the present invention; 1 is a schematic plan view showing an endoscopic imaging device according to an embodiment of the present invention. 1 is a schematic side view showing an endoscopic imaging device according to an embodiment of the present invention. FIG. 2 is a schematic perspective view showing an example of a holder of the endoscopic imaging device according to the embodiment of the present invention. 2 is a schematic plan view showing a surface of an example of a circuit board of an endoscopic imaging device according to an embodiment of the present invention. FIG. 3 is a schematic plan view showing a rear surface of an example of a circuit board of the endoscopic imaging device according to the embodiment of the present invention. FIG. FIG. 2 is a schematic side view showing an example of a circuit board of the endoscopic imaging device according to the embodiment of the present invention. 5A to 5C are schematic plan views showing an example of a method for manufacturing a circuit board for an endoscope imaging device according to an embodiment of the present invention. 4 is a schematic side view showing an example of a connection form of a signal cable to a circuit board of the endoscopic imaging device according to the embodiment of the present invention. FIG. 4 is a schematic plan view showing an example of a connection form of a signal cable to a circuit board of the endoscopic imaging device according to the embodiment of the present invention. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an endoscopic imaging device and an endoscope according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
It should be noted that the drawings described below are illustrative for explaining the present invention, and the present invention is not limited to the drawings shown below.
In the following description, terms such as "parallel,""perpendicular," and "orthogonal" include a generally acceptable error range in the relevant technical field.

[Endoscope system]
An endoscopic system irradiates an observation area, such as the inside of a subject's body, with illumination light (not shown), captures an image of the observation area, generates a display image of the observation area based on the image signal obtained by capturing the image, and displays the display image.
FIG. 1 is a schematic diagram showing an example of an endoscope system according to an embodiment of the present invention.
The endoscopic system 10 includes an endoscope 12, a light source device 14, and a processor device 16. The endoscopic system 10 has a configuration similar to that of a general endoscope, except for an endoscopic imaging device 20 (see FIG. 2 ) of the endoscope 12, which will be described later.

The endoscope 12 has an endoscopic imaging device 20 (see FIG. 2). Although not shown in detail, the endoscope 12 has an insertion section that is inserted into the subject, an operation section that is connected to the insertion section, and a universal cord that extends from the operation section, and the insertion section is composed of a tip section, a bending section that is connected to the tip section, and a flexible section that connects the bending section and the operation section. The endoscopic imaging device 20 (see FIG. 2) will be described later.

The tip of the endoscope 12 is provided with an endoscopic imaging device 20 (see FIG. 2) that has an illumination optical system that emits illumination light to illuminate the observation site, or an imaging element and imaging optical system that capture an image of the observation site. The bending section is configured to be bendable in a direction perpendicular to the longitudinal axis of the insertion section, and the bending operation of the bending section is controlled by the operation section. In addition, the flexible section is configured to be relatively flexible so that it can be deformed to follow the shape of the insertion path of the insertion section.

The operation section is provided with buttons for operating the imaging operation of the endoscopic imaging device 20 (see FIG. 2) at the tip, knobs for operating the bending operation of the bending section, etc. The operation section is also provided with an introduction port through which a treatment tool such as an electric scalpel is introduced, and a treatment tool channel is provided inside the insertion section, which extends from the introduction port to the tip and through which a treatment tool such as forceps is inserted.

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 an illumination optical system at the tip, and a processor device 16 that processes video signals acquired by an endoscopic imaging device 20 (see Figure 2) at the tip.

The processor unit 16 processes the input video signal to generate video data of the observed area, and displays the generated video data on a monitor (not shown) or records it on a storage medium such as a hard disk. The processor unit 16 may be configured by a processor such as a personal computer.

The light source device 14 generates illumination light such as white light or specific wavelength light consisting of three primary colors such as red (R), green (G), and blue (B), and supplies it to the endoscope 12, where it propagates through a light guide or the like within the endoscope 12 and is emitted from an illumination optical system at the tip of the insertion section of the endoscope 12 to illuminate the area to be observed within the body cavity, in order to capture an image of the area to be observed within the body cavity using the endoscopic imaging device 20 (see Figure 2) of the endoscope 12 and obtain an image signal of the area to be observed.

A light guide or a group of electric wires (signal cables) are housed inside the insertion section, the operation 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 signals and power is transmitted between the endoscopic imaging device 20 (see FIG. 2) at the tip and the processor device 16 via the group of electric wires.
In addition, the tip of a treatment instrument channel (not shown) and an illumination optical system (not shown) that emits illumination light guided from the light source device 14 via a light guide are accommodated and fixed in an accommodation hole (not shown) formed at the tip of the endoscopic system 10.
For example, the endoscopic imaging device 20 is fixed to the tip of the endoscope system 10 with the light receiving surface 29a (see FIG. 4) of the imaging element 29 (see FIG. 4) approximately perpendicular to the longitudinal axis of the insertion portion.

The endoscope system 10 may further include a water tank for storing cleaning water, etc., and a suction pump for sucking up the aspirated material from within the body cavity (including the supplied cleaning water, etc.). It may also include a supply pump for supplying cleaning water from the water tank or gas such as external air to a duct (not shown) within the endoscope.

[Endoscope imaging device]
FIG. 2 is a schematic perspective view showing an endoscopic imaging device of an embodiment of the present invention, FIG. 3 is a schematic partial cross-sectional perspective view showing an endoscopic imaging device of an embodiment of the present invention, FIG. 4 is a schematic plan view showing an endoscopic imaging device of an embodiment of the present invention, and FIG. 5 is a schematic side view showing an endoscopic imaging device of an embodiment of the present invention.
An endoscopic imaging device 20 shown in Fig. 2 is mounted on the tip of an endoscope 12 of an endoscopic system 10 shown in Fig. 1. The endoscopic imaging device 20 is also called a camera head.

The endoscopic imaging device 20 shown in Figures 2 to 5 is for acquiring images of an object to be observed. The endoscopic imaging device 20 has an imaging lens 23 (see Figure 3), a lens barrel 22 that holds the imaging lens 23, a holder 24, a filter 26, a mask 27, a cover glass 28, an imaging element 29, a circuit board 30, and a signal cable 32. The endoscopic imaging device 20 also has an anchor 34.

The lens barrel 22 is a cylindrical member and, although not shown, holds one or more imaging lenses 23 in an interior 22a (see FIG. 3 ). The lens barrel 22 holds the imaging lenses 23 so that an optical axis C of the imaging lens 23 is perpendicular to a light receiving surface 29a of the imaging element 29. The endoscopic imaging device 20 has, for example, four imaging lenses 23, although not shown in detail.
2, 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 is defined as the Z direction. The Y direction corresponds to the width direction of the endoscopic image capturing device 20. The Z direction corresponds to the height direction of the endoscopic image capturing device 20, and is equivalent to the up-down direction described below.

The imaging lens 23 is an optical element that forms an image of light incident on the imaging lens 23 on a light receiving surface 29a (see FIG. 4) of the imaging element 29. The imaging lens 23 is held by the lens barrel 22.
There are no particular limitations on the configuration of the imaging lens 23 and the lens barrel 22. For example, the imaging lens 23 may be one, or the imaging lens 22 may be two, three, or five or more. Each imaging lens 23 may be a convex lens or a concave lens.

The imaging element 29 is an imaging element that captures an image by converting light focused by the imaging lens 23 into an electrical signal through photoelectric conversion. The imaging element 29 is a conventionally known imaging element, and may be a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.
A cover glass 28 is disposed on a light receiving surface 29a of the image sensor 29, and the cover glass 28 protects the light receiving surface 29a. The image sensor 29 and the cover glass 28 are, for example, integral with each other, and the cover glass 28 constitutes a part of the image sensor 29. Note that unless otherwise specified, the positioning of the image sensor 29 also includes the positioning of the image sensor 29 using the cover glass 28.
Moreover, the image pickup element 29 may be configured without the cover glass 28 .

The imaging element 29 is held by the holder 24. The imaging element 29 is electrically connected to the circuit board 30, for example, via conductive bumps 33 (see FIG. 4). As shown in FIG. 4, the imaging element 29 is mounted on the circuit board 30 so that the light receiving surface 29a is orthogonal to the optical axis C of the imaging lens 23. In other words, the optical axis C of the imaging lens is perpendicular to the light receiving surface 29a of the imaging element 29. Note that "mounted" means "electrically connected."
An underfill layer (not shown) may be provided between the imaging element 29 and the circuit board 30 in order to firmly connect the imaging element 29 and the circuit board 30 .

The bumps 33 are made of a metal or an alloy. More specifically, the bumps 33 are made of solder. The bumps 33 made of solder are also called solder balls. Note that the bumps 33 are not limited to solder or the like as long as they can electrically connect the imaging element 29 and the circuit board 30. The imaging element 29 and the circuit board 30 may be electrically connected using an anisotropic conductive film, or may be electrically connected directly.
The underfill layer also relieves stress that occurs at the joints between the imaging element 29 and the circuit board 30, such as the bumps 33, due to the difference in thermal expansion coefficient between the imaging element 29 and the circuit board 30. The underfill layer firmly connects the imaging element 29 and the circuit board 30, increasing the reliability of the electrical connection, and providing a highly reliable endoscopic imaging device 20.
The underfill agent constituting the underfill layer is not particularly limited, and any agent that is used as a sealing resin between the image sensor 29 and the circuit board 30 can be appropriately used. For example, a one-component heat-curing epoxy resin is used as the underfill agent. In this case, after the underfill agent is supplied, it is heated and held at a predetermined temperature to form the underfill layer.

The circuit board 30 is a board on which the imaging element 29 is mounted. In addition to the imaging element 29, for example, electronic components 31 are mounted on the circuit board 30. The electronic components 31 are for driving the imaging element 29, and include, but are not limited to, for example, a voltage regulator, a resistor, and a capacitor. The voltage regulator is a device that stabilizes the voltage to the imaging element 29, and outputs a constant voltage to the imaging element 29.
Further, the front surface 30a of the circuit board 30 is provided with a plurality of connection terminals 40 through which signals or power are input and output to and from the imaging element 29 and the electronic components 31. A signal line 32a of the signal cable 32 is electrically connected to the connection terminals 40. In addition to the connection terminals 40, the circuit board 30 has a signal line 41 and a connection portion 42, etc., as described below. The front surface 30a of the circuit board 30 corresponds to, for example, one side of the circuit board 30. Also, a rear surface 30g (see FIG. 8 ) of the circuit board 30 described below corresponds to, for example, the other side. The side opposite to the one side is the other side. That is, for example, the side opposite to the front surface 30a of the circuit board 30 is the rear surface 30g.

In the illustrated example, the circuit board 30 has a shape obtained by bending a plate-like member at one place, and has a curved portion 30c (see FIGS. 2 and 5). Specifically, the circuit board 30 is bent in a direction perpendicular to the optical axis C direction of the imaging lens 23, that is, with respect to an axis extending in the Y direction. The circuit board 30 has a tip portion 30b (see FIG. 3) on the tip side of the curved portion 30c extending in the Z direction, and the tip portion 30b is electrically connected to the imaging element 29. The rear end side of the curved portion 30c extends in the optical axis C direction, and an electronic component 31 is mounted on a surface 30a on the rear end 30p (see FIGS. 7 to 9 described later) side of the circuit board 30, and a connection terminal electrically connected to a signal cable 32 is provided. In addition, a connection pad 30d is provided on the surface 30a of the circuit board 30, and the connection pad 30d is electrically connected to a metal layer 30h (see FIG. 8). The configuration of the circuit board 30 will be described later.
The shield conductor 32c of the signal cable 32 is electrically connected to the connection pad 30d by soldering or the like, and the potential of the shield conductor 32c is set to the ground potential. This increases the noise resistance of the endoscopic imaging device 20 and reduces the effect of noise on the imaging element 29. The signal cable 32 is electrically connected to the imaging element 29 as described below, which will be described later.

The circuit board 30 is preferably a flexible board, and is, for example, a flexible printed circuit board. The circuit board 30 is not limited to being curved at one location, and the number of curved locations is appropriately determined depending on the configuration of the endoscopic imaging device 20. The arrangement of the imaging element 29, electronic components 31, connection terminals, etc. on the circuit board 30 is not particularly limited.
5, the curved portion 30c of the circuit board 30 may protrude from a lower end face 34g of the anchor 34 in the Z direction, i.e., the up-down direction, of the endoscopic imaging device 20. By making the curved portion 30c protrude from the lower end face 34g of the anchor 34 in this manner, the curvature of the curved portion 30c of the circuit board 30 can be increased. In other words, the radius of curvature of the curved portion 30c of the circuit board 30 can be reduced. Also, by making the curved portion 30c of the circuit board 30 protrude from the lower end face 34g of the anchor 34, the space below the anchor 34 can be effectively utilized.
The lower end surface 34 g of the anchor 34 is the lower surface of the bottom portion 34 a of the anchor 34 .

A signal cable 32 is connected to a connection terminal 40 on the surface 30a of the circuit board 30, and the image sensor 29 and the signal cable 32 are electrically connected. The image sensor 29 converts light into an electrical signal, and this electrical signal is transmitted via the signal cable 32. The signal cable 32 is inserted through the insertion section, operation section, universal cord, etc. of the endoscope, and is electrically connected to the processor device 16 (see FIG. 1). Note that the signal cable 32 is not particularly limited as long as it has an outer cover 32d that forms the outer periphery.

2 and 4, the signal cable 32 includes, for example, a plurality of signal lines 32a, a covering layer 32b covering each of the signal lines 32a, a shield conductor 32c provided around the entirety of the plurality of signal lines 32a covered with the covering layer 32b, and an outer sheath 32d covering the shield conductor 32c. As described above, the outer sheath 32d forms the outer periphery of the signal cable 32. The covering layer 32b, the shield conductor 32c, and the outer sheath 32d are, for example, cylindrical. The shield conductor 32c of the signal cable 32 is called a shield. The signal cable 32 includes, for example, four signal lines 32a. The number of signal lines 32a depends on the configuration of the endoscopic imaging device 20 and is not particularly limited, and may be two, three, five or more.
The signal cable 32 is a multi-core cable in which a plurality of signal wires 32a are bundled together, surrounded by a shield conductor 32c, and housed within a cylindrical outer sheath 32d.

FIG. 6 is a schematic perspective view showing an example of a holder of an endoscope imaging apparatus according to an embodiment of the present invention.
6 is a member that is connected to the lens barrel 22 and holds the image sensor 29. The holder 24 is a substantially cylindrical member, and has a mounting cylinder portion 24a that has a through hole 24d into which the lens barrel 22 is attached.
The lens barrel 22 (see FIG. 2) is fitted into the through hole 24d to hold the lens barrel 22. The inner surface of the holder 24 and the outer circumferential surface of the lens barrel 22 are fixed together by, for example, adhesive.
Various known adhesives used in conventional endoscopes can be used as the adhesive for bonding the holder 24 and the lens barrel 22. For example, an epoxy adhesive, a silicone adhesive, or an acrylic adhesive can be used as the adhesive, and the same can be used for adhesives for bonding other members together.
The lens barrel 22 is adhesively fixed to the holder 24 with the relative position with respect to the holder 24 in the direction of the optical axis C of the imaging lens 23 (see FIG. 3) adjusted so that the light receiving surface 29 a of the imaging element 29 is in focus.

The holder 24 has a polygonal flange portion 24b on the opposite side of the mounting tube portion 24a to the side where the lens barrel 22 is attached. The flange portion 24b has a pair of regulating members 25 on the opposite side of the mounting tube portion 24a. The pair of regulating members 25 are provided facing each other. The pair of regulating members 25 have the same shape and size, and are formed of, for example, a rectangular flat plate.
In the holder 24, the pair of regulating members 25 are provided facing each other on the surface 24c of the flange portion 24b opposite the mounting tube portion 24a, as described above. For example, the facing direction in which the pair of regulating members 25 face each other is perpendicular to the optical axis direction of the optical axis C of the imaging lens 23. The facing direction is, for example, a direction parallel to the Y direction. Note that the optical axis direction of the optical axis C is the extension direction of the optical axis C.
Here, the above-mentioned up-down direction is the direction in which the pair of regulating members 25 face each other and the direction perpendicular to the optical axis direction.

The imaging element 29 is held, for example, by a pair of regulating members 25 of the holder 24. As shown in Figures 2 and 3, between the surface 24c of the flange portion 24b of the holder 24 and the imaging element 29, the filter 26, the mask 27, and the cover glass 28 are arranged in this order from the flange portion 24b side of the holder 24. The filter 26, the mask 27, the cover glass 28, and the imaging element 29 have approximately the same shape and approximately the same size in a planar view, for example, a rectangle in a planar view. The filter 26, the mask 27, and the cover glass 28 are also held by a pair of regulating members 25.

2 is for suppressing the incidence of flare and the like on the light receiving surface 29a of the image sensor 29. The filter 26 is made of, for example, glass.
The mask 27 restricts a portion of the light that has passed through the imaging lens 23, and prevents stray light and the like from entering the imaging element 29. The mask 27 is, for example, a plate-like member in which a circular hole 27a (see FIG. 3) is provided in an area corresponding to the through-hole 24d. When the through-hole 24d is viewed from the optical axis direction of the optical axis C of the imaging lens 23, the mask 27 blocks the entire outer edge of the through-hole 24d. The mask 27 is made of, for example, stainless steel, synthetic resin, brass alloy, aluminum alloy, or the like.

The mask 27 is in contact with the filter 26 and the cover glass 28 on both sides in the optical axis direction. The mask 27, the filter 26, and the cover glass 28 are bonded together using, for example, a photocurable adhesive. When bonding is performed using a photocurable adhesive, the filter 26 and the cover glass 28 in contact with both sides in the optical axis direction of the mask 27 preferably transmit light of a wavelength at which the photocurable adhesive cures. Even if the filter 26 or the cover glass 28 is not provided on both sides in the optical axis direction of the mask 27, it is preferable that the members in contact with both sides in the optical axis direction of the mask 27 transmit light of a wavelength at which the photocurable adhesive cures.
In addition, the term "transmitting light having a wavelength at which the photocurable adhesive hardens" means that the material has a transmittance sufficient to allow the photocurable adhesive to adhere.
The photocurable adhesive is, for example, an adhesive that is cured by ultraviolet light with a wavelength of about 100 to 400 nm, visible light with a wavelength of more than 400 and less than 780 nm, or infrared light with a wavelength of about 780 nm to 1 mm.
The photocurable adhesive may be, for example, an epoxy resin-based photocurable adhesive, an acrylic resin-based photocurable adhesive, or a silicone-based photocurable adhesive. Alternatively, the photocurable adhesive may be a combination of photocurable and heat-curable adhesive.

2 to 5 serves to hold the signal cable 32 relative to the holder 24. The anchor 34 also maintains the mechanical strength of the endoscopic imaging device 20.
2, the anchor 34 has a flat bottom portion 34a formed by bending a single plate material, and a holding portion 34d having a flat base portion 34c continuous with the bottom portion 34a. The holding portions 34d are provided opposite each other in the Y direction, and hold the signal cable 32 as described below.
In the anchor 34, the holding portion 34d side is the base end 35a. The base material portion 34c is bent, for example, by crimping, so as to fit along the outer sheath 32d of the signal cable 32. As a result, the signal cable 32 is fixed and held by the holding portion 34d. When the base end 35a of the anchor 34 is viewed in the optical axis direction with the signal cable 32 fixed to the holding portion 34d, for example, a substantial triangle is formed by the pair of holding portions 34d and the bottom portion 34a. As a result, the application of a load to the circuit board 30 is suppressed, and deformation of the circuit board 30 is suppressed.

The anchor 34 also has arm portions 34b that extend linearly from the bottom portion 34a. The pair of arm portions 34b face each other. The arm portions 34b are provided on the base end 35a side, physically separated from the substrate portion 34c by a gap 34e. This prevents deformation of the arm portions 34b from being transmitted to the holding portion 34d, and prevents deformation of the holding portion 34d from being transmitted to the arm portions 34b.

The opposing direction in which the pair of arm portions 34b face each other is the same direction in which the pair of regulating members 25 face each other, and is perpendicular to the optical axis direction of the optical axis C of the imaging lens 23. The opposing direction in which the pair of arm portions 34b face each other is, for example, parallel to the Y direction.
The distance between the pair of arm portions 34 b is appropriately determined in accordance with the arrangement of the regulating member 25 of the holder 24 .
A pair of arms 34b on the tip 35b side of the anchor 34 are fixed to sandwich the restricting member 25 of the holder 24. The arms 34b are fixed to an outer surface 25c (see FIGS. 2 and 6) on the outside of the restricting member 25. The outer surface 25c of the restricting member 25 is the surface opposite to an inner surface 25f on which a recess 25d (see FIG. 6) is provided.
Fixing the arm portion 34b to the outer surface 25c on the outside of the restricting member 25 suppresses interference of the arm portion 34b when positioning the holder 24 and the image sensor 29, and also suppresses interference with the circuit board 30. Furthermore, by fixing the arm portion 34b to the outer surface 25c on the outside of the restricting member 25, the restricting member 25 can be used to position the image sensor 29, and the positional accuracy of the image sensor 29 and the image sensor 23 of the lens barrel 22 can be increased.

2 and 5, each arm portion 34b is provided with, for example, a groove 34f at the end portion on the tip 35b side. For example, solder 37 is supplied to the groove 34f, and the arm portion 34b is fixed to the regulating member 25 of the holder 24. The shape of the groove 34f is not particularly limited, and for example, the groove 34f has a curved bottom. In this case, the groove 34f is called a U-shaped groove. Also, for example, the groove 34f may have a polygonal bottom. In this case, the groove 34f is called a V-shaped groove. Also, the groove 34f is not limited to the above-mentioned groove 34f, and a through hole (not shown) may be provided in the arm portion 34b. The shape of the through hole is not particularly limited, and for example, it is a circle, an ellipse, or a polygon.
In addition, if the arm portion 34b has a groove 34f or a through hole in the area fixed to the holder 24, specifically, in the portion that contacts the outer surface 25c of the regulating member 25, it is preferable because the joining area can be increased when the arm portion 34b is joined and fixed to the holder 24 using solder 37.

The anchor 34 is formed, for example, from a metal material. The metal material from which the anchor 34 is formed is not particularly limited, but considering workability, availability, strength, etc., stainless steel and copper alloys are preferable for the anchor 34. When the anchor 34 is fixed using solder 37, it is preferable to subject the anchor 34 to a plating process that makes it easier for the solder 37 to adhere.

By connecting the anchor 34 to the holder 24 and the signal cable 32, respectively, when the signal cable 32 is pulled, the connection between the connection terminal 40 on the circuit board 30 and the signal line 32a of the signal cable 32 is pulled, preventing the connection between the connection terminal 40 and the signal line 32a from being broken.

The signal cable 32 is fixed to the anchor 34 using, for example, an adhesive or solder (not shown). It is preferable to use solder to join the holding portion 34d of the anchor 34 and the shield conductor 32c of the signal cable 32. By using solder, the potential including the anchor 34 can be set to the ground potential, and the electrical resistance at the joint can be reduced. This increases noise resistance and reduces the effect of noise on the imaging element 29. Furthermore, by using solder, the mechanical strength at the joint can be increased.
In the endoscopic imaging device 20, the circuit board 30 and the signal cable 32 are joined together using solder, and then the holding portion 34d of the anchor 34 and the signal cable 32 are joined together using solder.

Here, Fig. 7 is a schematic plan view showing a front surface of an example of a circuit board of an endoscopic imaging device according to an embodiment of the present invention, Fig. 8 is a schematic plan view showing a rear surface of an example of a circuit board of an endoscopic imaging device according to an embodiment of the present invention, and Fig. 9 is a schematic side view showing an example of a circuit board of an endoscopic imaging device according to an embodiment of the present invention.
7, a connection terminal 40, a signal line 41, and a connection portion 42 are provided on a surface 30a of the circuit board 30. The connection terminal 40, the signal line 41, and the connection portion 42 are electrically connected to each other.
The signal cable 32 (see FIG. 2) is electrically connected to the connection terminal 40 by soldering, etc. For example, the connection terminal 40 to which the signal cable 32 (see FIG. 2) is connected becomes a hardness change point.
The signal line 41 is made of a conductor and serves as a relay between the connection terminal 40 and the connection portion 42 , and an electrical signal from the imaging element 29 is transmitted from the connection portion 42 to the connection terminal 40 and then to the signal cable 32 .
The connection portion 42 is provided in a region 43 on the front surface 30a of the circuit board 30 opposite to the back surface 30g on which the imaging element 29 is provided. The connection portion 42 also extends in the thickness direction of the circuit board 30. The above-mentioned region 43 is located at the tip portion 30b of the circuit board 30.
Furthermore, the connection portion is electrically connected to a connection member 44 on the rear surface 30g of the circuit board 30. The signal line 41 and the connection member 44 are electrically connected by the connection portion .

The connection member 44 electrically connects the imaging element 29 and the circuit board 30. The connection member 44 is provided on the rear surface 30g of the circuit board 30.
The number of connection terminals 40, the number of signal lines 41, and the number of connection portions 42 are the same as the number of output terminals (not shown) of the imaging element 29 (see FIG. 2).

The configuration of the connection portion 42 is not particularly limited as long as it can electrically connect the signal line 41 and the connection member 44. The connection portion 42 is composed of a conductor arranged in the thickness direction of the circuit board 30, and is generally called a via. Examples of the via include a plated through hole, a via hole, and a filled via.
The connection member 44 is electrically connected to the imaging element 29, and the configuration thereof is not particularly limited, and examples thereof include connection terminals or solder balls.
When the imaging element 29 is connected to the connection member 44, the connection point of the imaging element 29 becomes a hardness change point.

As shown in FIG. 7, on the front surface 30a of the circuit board 30, the above-mentioned connection pad 30d is provided on the opposite side of the connection terminal 40 from the connection portion 42.
8, a metal layer 30h is provided on the rear surface 30g of the circuit board 30. The connection pads 30d (see FIG. 7) are electrically connected to the metal layer 30h. Both the connection pads 30d and the metal layer 30h are conductive films.
When the circuit board 30 is viewed from the front surface 30a (see FIG. 7) or rear surface 30g (see FIG. 8), the metal layer 30h overlaps the connection pads 30d and is provided over a larger area than the connection pads 30d.
The metal layer 30h also has a function of reinforcing the strength of the circuit board 30. The metal layer 30h can prevent local bending at the hardness change point and prevent disconnection of wiring such as the signal line 41 of the circuit board 30. Even if the circuit board 30 has a curved portion 30c (see FIG. 2), it is possible to prevent local bending at the hardness change point and prevent disconnection of wiring such as the signal line 41 of the circuit board 30.
Furthermore, when the circuit board 30 is small and thin due to miniaturization of the endoscopic imaging device 20, the signal lines 41, etc. also need to be thin. In this case, bending the circuit board 30 may cause the circuit board 30 to break or the wiring such as the signal lines 41 to be disconnected. However, by providing the metal layer 30h so as to overlap the connection pads 30d and in an area wider than the connection pads 30d as described above, it is possible to prevent damage such as breaking of the circuit board 30 and disconnection of the wiring such as the signal lines 41 of the circuit board 30.

Furthermore, since the metal layer 30h also serves as a noise shielding layer, high frequency signals input to and output from the imaging element 29 or the electronic component 31 are less likely to be disturbed.
In addition, the connection pad 30d is also an electrical resistance change point. For example, noise occurs when the imaging element 29 is driven. Even if noise occurs in this manner, the metal layer 30h can prevent leakage of noise generated from the imaging element 29 and the like, and can also block noise from the outside of the endoscopic imaging device 20.
It is preferable that the metal layer 30h is electrically connected to the ground, so that the metal layer 30h has a ground potential, and functions as a noise shielding layer more effectively, so that high-frequency signals input to and output from the imaging element 29 or the electronic component 31 are more unlikely to be disturbed.

Here, the ground of the insertion portion of the endoscope (including the sensor) is generally as shown below.
The ground is a metal part that is connected to the earth in an alternating current manner via a capacitor or the like. High-frequency currents (MHz to GHz noise) are released to the earth, but leakage currents (several hundred kHz) from electric scalpels and other devices, and direct currents are insulated from the earth to prevent electric shock (to prevent the formation of a closed circuit between the human body and the earth). This part also serves as the potential reference for each part of the device. Signal lines can be prevented from being affected by other potentials (noise) by passing them through an area surrounded by the reference potential as much as possible.

The area where the metal layer 30h is provided is wider than the area of the connection pad 30d. The area where the metal layer 30h is provided is wider than the area of the connection pad 30d. In this case, it is preferable that the metal layer 30h is larger than the area of the connection pad 30d by about three times the thickness of the circuit board 30.
Here, the curved portion 30c of the circuit board 30 is formed by bending the circuit board 30, but it is easier to bend the circuit board 30 and form the curved portion 30c without the metal layer 30h. For this reason, the upper limit of the range in which the metal layer 30h is provided is preferably from the rear end 30p (see FIGS. 7 to 9) of the circuit board 30 to just before the curved portion 30c.

Here, the metal layer 30h overlapping the connection pads 30d means that the connection pads 30d are entirely within the metal layer 30h.
The connection pads 30d, the metal layer 30h, the connection terminals 40, the signal lines 41, the connection parts 42, and the connection members 44 of the circuit board 30 are made of copper, for example, like the wiring layers of the flexible printed circuit board. The metal layer 30h can be made of copper, copper alloy, aluminum, aluminum alloy, stainless steel, or the like, in addition to the above-mentioned copper.

The imaging element 29 is electrically connected to a connection member 44, electrically connected to the circuit board 30, and provided on the back surface 30g of the circuit board 30. In an area 43 on the front surface 30a opposite to the back surface 30g of the circuit board 30 on which the imaging element 29 is provided, a connection member 44 on the back surface 30g of the circuit board 30 is electrically connected to a signal line 41 via a connection portion 42. In this manner, the imaging element 29 is electrically connected to the signal line 41. The signal line 41 is provided on the front surface 30a of the circuit board 30 as described above.
Although a point of change in hardness occurs in the region 43 of the tip portion 30b due to the connection portion 42, the curved portion 30c can be avoided, so that damage to the circuit board 30 can be prevented.
Moreover, since the signal line 41 and the connection portion 42 can be arranged on the front surface 30a side of the circuit board 30, i.e., on the same surface side, two-surface wiring between the front surface 30a and the back surface 30g of the circuit board 30 is not required, simplifying the wiring structure of the circuit board 30. Also, since there is no need to provide signal lines, etc. on the back surface 30g side of the circuit board 30, mechanical contact of the signal lines, etc. of the circuit board 30 can be suppressed, and breakage of the signal lines of the circuit board 30 can also be prevented.
Furthermore, since the circuit board 30 does not require two-sided wiring as described above, the thickness of the circuit board 30 can be made thinner, and the outer diameter of the endoscopic imaging device 20 can be made smaller.

Although the circuit board 30 has connection pads 30d on the front surface 30a and a metal layer 30h on the rear surface 30g of the circuit board 30, the metal layer 30h is not limited to being provided on the rear surface 30g of the circuit board 30.
When the circuit board 30 has a multilayer wiring structure, for example, the connection pads 30d are provided on the front surface 30a of the circuit board 30. The metal layer 30h may be provided on the back surface of the circuit board with the multilayer wiring structure, or may be provided on a surface of another layer of the multilayer wiring layers of the circuit board with the multilayer wiring structure on which the connection pads 30d are not provided. The other layer is a layer inside the circuit board. The surface of the other layer refers to any one of the surfaces of the other layer that faces each other in the stacking direction of the circuit board with the multilayer wiring structure.
The metal layer 30h may be provided on the surfaces of multiple layers of the multilayer wiring layer, including the other layers described above on which the connection pads 30d are not provided. That is, the metal layer 30h may be provided on multiple layers of the multilayer wiring layer. The surfaces of the multiple layers correspond to the surfaces on the opposite side to the surface of the circuit board with the multilayer wiring structure described above. The surfaces of the multiple layers, like the other layers, are any of the surfaces facing each other in the stacking direction of the circuit board with the multilayer wiring structure.
The other surface opposite to the one surface includes the surface of another layer of the multi-layer wiring layer on which the metal layer 30h is provided, and further includes the surfaces of the above-mentioned multiple layers.

Depending on the configuration of the imaging element 29, a large number of wirings may be required. In the case of such an imaging element 29, wirings must also be provided on the back surface of the circuit board, and the metal layer 30h may not be provided on the back surface of the circuit board. In this case, the metal layer 30h may be provided on the surface of the other layer or on the surfaces of multiple layers including the other layer.
As described above, in a circuit board having a multilayer wiring structure, by providing metal layer 30h on the surface of another layer of the multilayer wiring layer, it is possible to obtain the effect of preventing breakage of the circuit board, such as local breakage at the above-mentioned hardness change point.
Furthermore, when the metal layer 30h is provided on the surfaces of multiple layers, including the above-mentioned other layers on which the connection pads 30d are not provided, among the multi-layer wiring layers, the strength of the circuit board is further increased, and the circuit board becomes more resistant to breaking. In addition, when the metal layer 30h is provided on the surfaces of multiple layers, the cross-sectional area increases, so that the electrical resistance of the metal layer 30h becomes lower, and noise can be more easily released from the shield conductor 32c of the signal cable 32.

The circuit board 30 is provided with a recess 45 connected by a connecting portion 46 to a side surface 30e in a width direction Dw perpendicular to the extension direction Ds of the circuit board 30. For example, the recesses 45 are arranged at two intervals along the extension direction Ds of the circuit board 30, and the two recesses 45 are connected by a connecting portion 46. The connecting portion 46 between the recesses 45 is located inside the circuit board 30 from the side surface 30e. This makes it possible to easily remove the runner portion 48a (see FIG. 10) in the recess 45 when the circuit board 30 is divided into individual pieces as described later. Furthermore, it is possible to prevent damage to the circuit board 30 when the circuit board 30 is divided into individual pieces as described later. In addition, by making the connecting portion 46 inside the circuit board 30 from the side surface 30e, the width of the circuit board 30 can be narrowed and interference with other members can be prevented.
The shape of the recess 45 is not particularly limited, but from the viewpoint of efficiently dividing the circuit board 30 into individual pieces, it is preferable that the bottom of the recess 45 be an arc when viewed from the front surface 30a side of the circuit board 30.
The connecting portion 46 is formed by cutting a cutting line 49 (see FIG. 10 ) as described below. The shape of the connecting portion 46 reflects the machining marks and machining accuracy of the machining tool used to cut the cutting line 49. Therefore, although the connecting portion 46 is parallel to the side surface 30e of the circuit board 30 in FIG. 7 and FIG. 8 , the connecting portion 46 is not limited to this and may have various shapes.

As shown in FIG. 9, the circuit board 30 has, in this order, a tip portion 30b on which the imaging element 29 is provided, a curved portion 30c, an inclined portion 30j, and a rear end portion 30k on which connection pads 30d are provided.
The first folding axis _Lb1 and the second folding axis _Lb2 shown in Figures 7 and 8 are axes extending in the width direction Dw perpendicular to the extending direction Ds of the circuit board 30. With respect to the circuit board 30 in the state shown in Figures 7 and 8, the portion beyond the first folding axis Lb1 is raised so that the surface _30a of the circuit board 30 approaches each other to form the tip portion 30b and the curved portion 30c. Next, the portion behind the second folding axis _Lb2 is lowered downward to form the inclined portion 30j and the rear end portion 30k. In this manner, the tip portion 30b, the curved portion 30c, the inclined portion 30j, and the rear end portion 30k shown in Figure 9 are formed.

An electronic component 31 for driving the imaging element 29 is provided on the surface 30a side of the circuit board 30 of the inclined portion 30j shown in FIG.
The inclined portion 30j is inclined but flat. By providing the electronic component 31 on the inclined portion 30j between the curved portion 30c and the rear end portion 30k, rather than on the rear end portion 30k, the space of the circuit board 30 can be effectively utilized, and there is no need to provide space for mounting the electronic component 31, allowing the endoscopic imaging device 20 to be made smaller.
The inclined portion 30j can be formed, for example, by applying an adhesive and fixing it with a jig (not shown).
The adhesive may be any of various known adhesives used in conventional endoscopes, such as an epoxy adhesive, a silicone adhesive, or an acrylic adhesive.
Furthermore, by providing the metal layer 30h and positioning the connection portion 46 between the recesses 45 on the inner side of the circuit board 30 relative to the side surface 30e, the inclined portion 30j can be formed.
In the circuit board 30, the portion with the metal layer 30h is difficult to bend, and therefore the inclined portion 30j (flat surface) is easy to form, whereas the portion without the metal layer 30h is easy to bend, and therefore the curved portion 30c is easy to form. Therefore, by providing the metal layer 30h, the inclined portion 30j can be easily formed continuous with the curved portion 30c.

Here, FIG. 10 is a schematic plan view showing an example of a method for manufacturing a circuit board for an endoscope imaging device according to an embodiment of the present invention.
FIG. 10 shows a state in which one circuit board 30 is attached to a flexible board 47 .
Although not shown, a plurality of circuit boards 30 are surface-mounted on the flexible substrate 47 .
10, cut lines 48 are provided around the periphery of the circuit board 30. The cut lines 48 are, for example, line portions that penetrate the flexible board 47 and are arranged at intervals.
Also provided is a runner portion 48a that fits into the recess 45 (see FIG. 7). Similar to the cut lines 48, the runner portion 48a is, for example, a line portion that penetrates the flexible substrate 47 and is arranged at intervals. The recess 45 (see FIG. 7) is formed by removing the runner portion 48a.

A cutting line 49 for separating the circuit board 30 from the flexible board 47 is provided in contact with the two runner portions 48a. The portion connected by the cutting line 49 becomes the above-mentioned connecting portion 46 of the circuit board 30. The cutting line 49 is provided parallel to the portion that will become the side surface 30e of the circuit board 30 and is provided inside the portion that will become the side surface 30e of the circuit board 30 (see FIG. 7).
The flexible substrate 47 has a different wiring pattern and the like from the circuit substrate 30, but is basically the same substrate and is formed, for example, of a flexible printed circuit board.

The imaging element 29 is electrically connected to the circuit board 30 while attached to the flexible board 47. After the imaging element 29 is connected, the flexible board 47 is cut along the cutting lines 49, and the flexible board 47 is removed at the cut lines 48 and the runner portions 48a, thereby dividing the circuit board 30 into individual pieces.
When the circuit board 30 is small, it may be difficult to connect the imaging element 29 after singulation. However, by connecting the imaging element 29 to the circuit board 30 before singulation of the circuit board 30, it is easy to connect the imaging element 29 even if the circuit board 30 is small. After singulation of the circuit board 30, the circuit board 30 is bent as described above about the first bending axis _Lb1 and the second bending axis Lb2 shown in Fig. ₇ to form the tip portion 30b, the curved portion 30c, the inclined portion 30j, and the rear end portion 30k.

In the endoscopic imaging device 20, the observation image captured by the imaging element 29 from the imaging lens 23 is focused on the light receiving surface 29a of the imaging element 29 and converted into an electrical signal, which is output to the processor unit 16 (see FIG. 1) via the signal cable 32 and converted into a video signal, and the observation image is displayed on a monitor connected to the processor unit 16. In this case, the endoscopic imaging device 20 focuses an optical image on the image receiving surface of the imaging element with high precision, and a high-quality observation image can be obtained without image loss or out-of-focus.

6, the arm portion 34b (see FIG. 4) is fixed to the outer surface 25c of the restricting member 25. For example, since the arm portion 34b is fixed using solder 37 (see FIGS. 2 and 5), it is preferable to plate the area where the arm portion 34b is fixed, for example, the outer surface 25c of the restricting member 25, in order to make the solder 37 easier to adhere.
In the holder 24, for example, it is not desirable to apply solder to the surface 24c of the flange portion 24b, since the filter 26 is disposed thereon. In addition, it is not desirable to apply solder to the joint surface of the holder 24 with the lens barrel 22, i.e., the inner surface of the through hole 24d. It is preferable not to apply plating to the portions of the holder 24 where it is not desirable to apply solder.
Also, in the holder 24, a portion without a plated portion acting as a solder barrier may be provided between a portion where solder is not desired and a portion where solder is to be applied.
In the holder 24, the portions where soldering is not desired are, for example, the mounting cylinder portion 24a and a front surface 24e of the flange portion 24b on the mounting cylinder portion 24a side.

In addition, in the holder 24 shown in FIG. 4, the ends 25a in the optical axis direction of the pair of regulating members 25 are preferably located closer to the holder 24 than the circuit board 30. This reduces interference between the regulating members 25 and the circuit board 30 when positioning the image sensor 29. It is also more preferable that the ends 25a in the optical axis direction of the pair of regulating members 25 are located closer to the holder 24 than the ends of the image sensor 29 on the signal cable 32 side. This makes it possible to further reduce interference with the circuit board 30 while holding the image sensor 29.

The imaging element 29 is preferably positioned using the flange portion 24b of the holder 24 shown in Fig. 6, at least one of the pair of regulating members 25, and the end surface 25b in the vertical direction of the regulating member 25. That is, the imaging element 29 is positioned in the optical axis C direction (X-axis direction) by abutting against the surface 24c of the flange portion 24b of the holder 24, is positioned in the width direction (Y direction) by abutting against the inner surface 25f (see Figs. 4 and 6) of at least one of the pair of regulating members 25, and is positioned in the vertical direction (Z direction) by abutting against a jig (not shown) that contacts the end surface 25b of the regulating member 25. As a result, by using the end surface 25b of the regulating member 25 when positioning the imaging element 29, it is not necessary to provide a positioning portion, and the size of the endoscopic imaging device 20 can be suppressed.
For the above-mentioned positioning of the image pickup element 29 and the holder 24, the upper end surface of the regulating member 25 in the vertical direction may be used.

Here, the arm portion 34b is long, and even a slight tilt causes a large deviation, resulting in interference with other components. On the other hand, providing a large number of positioning portions would result in the size of the endoscopic imaging device 20. Therefore, in the endoscopic imaging device 20, it is preferable that the arm portion 34b of the anchor 34 is positioned by the flange portion 24b of the holder 24, the pair of regulating members 25, and the end faces of the regulating members 25 in the up-down direction. This makes it easier to position the arm portion 34b and the holder 24.
In addition, since the lens barrel 22, the image pickup element 29, and the anchor 34 can be positioned based on the holder 24, positioning with less cumulative tolerance is possible. This allows the number of positioning parts to be reduced, and prevents the endoscopic image pickup device 20 from becoming larger.
The positioning of the arm portion 34b and the holder 24 may be performed using either the upper end surface of the regulating member 25 in the vertical direction or the lower end surface 25b in the vertical direction.
When the end surface 25b of the regulating member 25 is used for positioning, for example, a jig (not shown) that comes into contact with the end surface 25b of the regulating member 25 is used.

As shown in FIG. 4 above, the optical axis C of the imaging lens 23 is not limited to being perpendicular to the light receiving surface 29a of the imaging element 29 in the endoscopic imaging device 20. For example, the optical axis C of the imaging lens 23 may be parallel to the light receiving surface 29a of the imaging element 29. In this case, for example, a prism (not shown) is used to guide the light that has passed through the imaging lens 23 to the light receiving surface 29a of the imaging element 29. For example, a right-angle prism is used as the prism. By using a right-angle prism, the light that has passed through the imaging lens 23 is bent at a right angle.

FIG. 11 is a schematic side view showing an example of a connection mode of a signal cable to a circuit board of an endoscopic imaging device of an embodiment of the present invention, and FIG. 12 is a schematic plan view showing an example of a connection mode of a signal cable to a circuit board of an endoscopic imaging device of an embodiment of the present invention.
11 and 12, the same components as those in the endoscopic imaging device 20 shown in FIGS. 1 to 5 and the circuit board 30 shown in FIGS. 7 to 9 are designated by the same reference numerals, and detailed description thereof will be omitted.
The endoscopic imaging device 20a shown in Figure 11 differs from the endoscopic imaging device 20 shown in Figures 1 to 5 in that it does not have an anchor 34 (see Figure 2), that the optical axis C of the imaging lens 23 is parallel to the light receiving surface 29a of the imaging element 29, that the signal cable 32 has eight signal lines (not shown), that it has a prism 50, and that the circuit board 52 is a straight board without any curved portions.Other than that, the configuration is similar to that of the endoscopic imaging device 20 shown in Figures 1 to 5 and the circuit board 30 shown in Figures 7 to 9.
11 and 12, the signal lines 32a and 54 are emphasized, and the covering layer 32b is simplified. Also, the imaging lens 23 is not shown.

In the endoscopic imaging device 20a, a cover glass 28 is provided on a light receiving surface 29a of an imaging element 29. The prism 50 is, for example, a right-angle prism in which an entrance surface 50a and an exit surface 50b are perpendicular to each other. The prism 50 is disposed between the lens barrel 22 and the imaging element 29.
The prism 50 is disposed so that an entrance surface 50a faces the surface on the base end side of the lens barrel 22. The prism 50 is disposed so that an exit surface 50b faces the light receiving surface 29a of the image sensor 29.
It should be noted that the prism 50 is an example of an optical member disposed between the lens barrel 22 and the image sensor 29, and the optical member is not limited to the prism 50 as long as it can bend the optical axis C of the image sensor 23 and guide the light that has passed through the image sensor 23 to the light receiving surface 29a of the image sensor 29. It should be noted that the prism 50 is not necessarily required depending on the position of the image sensor 29, and a configuration in which a different optical member is disposed may also be used.

The circuit board 52 has basically the same configuration as the circuit board 30 (see FIG. 2). The imaging element 29 is electrically connected to the front surface 52a of the circuit board 52 from the front end side. As shown in FIG. 12, a plurality of metal terminals 53, for example, eight metal terminals 53, are provided on the rear end 52e side of the imaging element 29. The metal terminals 53 are arranged in two rows, with four terminals in one group.
The metal terminal 53 is an end of a signal line (not shown) that is electrically connected to the imaging element 29. A connection pad 52c is provided on the rear end 52e side of the metal terminal 53. A metal layer 52d is provided on the rear surface 52b of the circuit board 52 as shown in FIG.
The connection pad 52c shown in Figures 11 and 12 has the same configuration as the connection pad 30d (see Figure 7) of the above-mentioned circuit board 30 (see Figure 7). The metal layer 52d shown in Figure 11 has the same configuration as the metal layer 30h (see Figure 8) of the above-mentioned circuit board 30 (see Figure 8). Both the connection pad 52c and the metal layer 52d are conductive films. The connection pad 52c is electrically connected to the metal layer 52d.

The metal terminal 53 shown in FIG. 12 is a terminal to which the signal lines 32a and 54 of the signal cable 32 are electrically connected, for example, by solder. The signal cable 32 has the same number of signal lines 32a and 54 as the metal terminals 53. The signal lines 32a and 54 of the signal cable 32 are connected to the metal terminal 53 by solder or the like, so that the metal terminal 53 becomes a hardness change point.

In the circuit board 52, the connection pads 52c and the metal layer 52d overlap the connection pads 52c and are provided over a wider area than the connection pads 52c when the circuit board 52 is viewed from the front surface 52a side, similar to the connection pads 30d and the metal layer 30h of the circuit board 30 described above. As a result, similar to the endoscopic imaging device 20 described above, the metal layer 52d reinforces the circuit board 52, prevents local bending at the hardness change points, and prevents disconnection of wiring such as signal lines (not shown) of the circuit board 52. Note that even if the circuit board 52 has a configuration that is a straight board without a curved portion, it is possible to prevent local bending at the hardness change points and prevent disconnection of wiring such as signal lines (not shown) of the circuit board 52.
Furthermore, since the metal layer 52d also serves as a noise shielding layer, high frequency signals input to and output from the imaging element 29 or the electronic component 31 are less likely to be disturbed.
The connection pad 52c is also an electrical resistance change point. For example, noise occurs when the imaging element 29 is driven. Even if noise occurs in this manner, the metal layer 52d can prevent leakage of noise generated from the imaging element 29 and the like, and can also block noise from the outside of the endoscopic imaging device 20.

Here, the metal layer 52d overlapping the connection pad 52c means that the connection pad 52c is entirely within the metal layer 52d, similar to the metal layer 30h and the connection pad 30d.
Moreover, the metal layer 52d being provided over a wider area than the connection pads 52c means that the area of the metal layer 52d is larger than the area of the connection pads 52c. In this case as well, similarly to the above-described metal layer 30h, it is preferable that the metal layer 52d is larger than the connection pads 52c by about three times the thickness of the circuit board 52.
The connection pads 52c, the metal layer 52d, the metal terminals 53 and the signal lines (not shown) of the circuit board 52 are made of copper, for example, like the wiring layers of the flexible printed circuit board.

In the endoscopic imaging device 20a, the signal line 32a of the signal cable 32 is electrically connected to the metal terminal 53. For example, when the signal cable 32 is pulled by the bending movement of the endoscope, the signal line 32a that has a short excess length and is subjected to a large tension first is likely to break among the multiple signal lines 32a. If the signal line 32a with a short excess length is thinner than the other lines, it is more likely to break. Therefore, as shown in FIG. 12, the excess length of the signal line 54 that is the thickest and strongest among the multiple signal lines 32a is made the shortest. As a result, the signal line 54 with the shortest excess length is subjected to tension first, but since the signal line 54 has a high strength, it is unlikely to break even if tension is applied. In this way, the occurrence of breakage of the signal lines of the signal cable 32 can be suppressed.
When producing the signal cable 32, one of the multiple signal lines is configured to be thicker than the other signal lines. The excess length of the thick signal line is made the shortest among the multiple signal lines, and is connected to the metal terminal 53 by, for example, soldering. Note that the signal cable 32 is not limited to a configuration in which one signal line is made thick, and multiple signal lines of different thicknesses may be prepared, and the excess length of the thickest signal line may be made the shortest among the multiple signal lines.
In addition, in the case of the circuit board 52, similarly to the circuit board 30 described above, if the circuit board 52 has a multilayer wiring structure, the metal layer 52d may be provided on a surface of another layer on which the connection pad 52c is not provided, or on the surfaces of multiple layers including the other layers, among the multilayer wiring layers of the circuit board having the multilayer wiring structure.

The present invention is basically configured as described above. The endoscopic imaging device and endoscope of the present invention have been described in detail above, but the present invention is not limited to the above-mentioned embodiment, and various improvements and modifications may be made without departing from the spirit and scope of the present invention.

REFERENCE SIGNS LIST 10 endoscopic system 12 endoscope 14 light source device 16 processor device 20, 20a endoscopic imaging device 22 lens barrel 22a interior 23 imaging lens 24 holder 24a mounting tube portion 24b flange portion 24c surface 24d through hole 24e front surface 25 regulating member 25a end portion 25b end surface 25c outer surface 25d recess 25f inner surface 26 filter 27 mask 27a hole 28 cover glass 29 imaging element 29a light receiving surface 30, 52 circuit board 30a, 52a surface 30b tip portion 30c curved portion 30d, 52c connection pad 30e side surface 30g, 52b rear surface 30h, 52d metal layer 30j inclined portion 30k Rear end portion 30p Rear end 31 Electronic component 32 Signal cable 32a, 54 Signal line 32b Covering layer 32c Shield conductor 32d Outer cover 33 Bump 34 Anchor 34a Bottom portion 34b Arm portion 34c Base material portion 34d Holding portion 34e Gap 34f Groove 34g End surface 35a Base end 35b Tip portion 37 Solder 40 Connection terminal 41 Signal line 42 Connection portion 43 Region 44 Connection member 45 Recess 46 Coupling portion 47 Flexible substrate 48 Slit line 48a Runner portion 49 Cutting line 50 Prism 50a Incident surface 50b Exit surface 53 Metal terminal C Optical axis Ds Extension direction Dw Width direction Lb ₁ First bending axis Lb ₂ Second bending axis

Claims (8)

An endoscopic imaging device for acquiring an image of an observation object,
a lens barrel having an imaging lens disposed therein;
an imaging element that receives light that has passed through the imaging lens and performs photoelectric conversion;
a circuit board to which the imaging element is electrically connected;
a signal cable electrically connected to the circuit board;
a connection pad to which the signal cable is electrically connected is provided on one surface of the circuit board, and a metal layer is provided on the other surface of the circuit board opposite to the one surface;
An endoscopic imaging device, wherein, when the circuit board is viewed from the one surface side or the other surface side, the metal layer overlaps the connection pad and is provided over an area larger than the connection pad. a signal line is provided on the one surface of the circuit board, and a connection member is provided on the other surface of the circuit board;
the imaging element is electrically connected to the connection member and provided on the other surface,
The endoscopic imaging device according to claim 1 , wherein the connection member is electrically connected to the signal line in a region of the one surface opposite to the other surface on which the imaging element is provided. The circuit board has a side surface in a width direction perpendicular to an extending direction of the circuit board, the side surface being connected to a recess by a connecting portion,
The endoscopic imaging device according to claim 1 , wherein the connecting portion is located on an inner side of the circuit board relative to the side surface. the circuit board has, in this order, a front end portion on which the imaging element is provided, a curved portion, an inclined portion, and a rear end portion on which the connection pads are provided;
4. The endoscopic imaging apparatus according to claim 1, wherein an electronic component for driving the imaging element is provided on the one surface of the circuit board of the inclined portion. The endoscopic imaging device according to any one of claims 1 to 4, wherein the optical axis of the imaging lens is perpendicular to the light receiving surface of the imaging element. The endoscopic imaging device according to any one of claims 1 to 4, wherein the optical axis of the imaging lens is parallel to the light receiving surface of the imaging element. The endoscopic imaging device according to any one of claims 1 to 6, wherein the metal layer is electrically connected to ground. An endoscope comprising an endoscopic imaging device according to any one of claims 1 to 7.