Imaging module and endoscope device

An imaging module includes: a solid-state imaging element including a light receiving face for receiving light; a mounting substrate including a connection portion which is located inside an imaging element projection area that is a projection area where the solid-state imaging element is projected in an optical axis direction and which is connected to a back surface of the solid-state imaging element on a distal end side of the mounting substrate, the mounting substrate on a rear end side being extended in the optical axis direction; and a metallic reinforcing member that has a sleeve shape open at both ends and covers the solid-state imaging element and the connection portion of the mounting substrate along the optical axis direction in a state where an inner circumferential surface of the reinforcing member is away from the solid-state imaging element and the mounting substrate.

BACKGROUND

1. Technical Field

The disclosure relates to an imaging module and an endoscope device including an insertion portion provided with the imaging module at a distal end thereof.

2. Related Art

Conventionally, in the medical field and the industrial field, endoscope devices are widely used for various examinations. Among them, a medical endoscope device can acquire an in-vivo image in a body cavity without incising a subject by inserting a flexible insertion portion, which has an elongated shape and which is provided with an imaging element at its distal end, into the body cavity of the subject such as a patient, and further the medical endoscope device can perform remedial treatment by projecting a treatment tool from the distal end of the insertion portion if necessary. Therefore, the medical endoscope device is widely used.

In such an endoscope device, an imaging module including the imaging element and a lens unit that forms an object image on a light receiving face provided on a surface of the imaging element are fitted into a rigid holding frame inside the distal end of the insertion portion. Then, as the imaging module, a mounting substrate on which an electronic component for driving the imaging element is mounted is arranged to be located within a projection area of the imaging element. In the case of the endoscope device, when the insertion portion is bent, there is a risk that a stress is applied to a connection portion between the imaging element and the mounting substrate through a signal cable extended in the insertion portion. To prevent the connection portion between the imaging element and the mounting substrate from being broken when such an external force is applied, at least a metallic reinforcing member for protecting the connection portion between the imaging element and the mounting substrate from the external force is fitted into the holding frame in the distal end of the insertion portion (for example, see Japanese Patent Application Laid-open No. 2007-68563). Here, to avoid influence from outside, such as static electricity and disturbance noise, to the imaging element, the mounting substrate, and the electronic component, the reinforcing member is placed sufficiently away from the imaging element, the mounting substrate, and the electronic component, and insulated from the imaging element, the mounting substrate, and the electronic component.

SUMMARY

In some embodiments, an imaging module includes: a solid-state imaging element including a light receiving face for receiving light on a surface of the solid-state imaging element; a glass lid attached to the solid-state imaging element so as to cover the light receiving face of the solid-state imaging element; a mounting substrate including a connection portion which is located inside an imaging element projection area that is a projection area where the solid-state imaging element is projected in an optical axis direction of the solid-state imaging element and which is connected and fixed to a back surface of the solid-state imaging element on a distal end side of the mounting substrate, the mounting substrate on a rear end side being extended in the optical axis direction; a plurality of electronic components mounted on the mounting substrate; a metallic reinforcing member that has a sleeve shape open at both ends and covers the solid-state imaging element and the connection portion of the mounting substrate along the optical axis direction in a state where an inner circumferential surface of the reinforcing member is away from the solid-state imaging element and the mounting substrate; and a solid-state imaging element holder in which an outer circumferential surface of the glass lid is fitted into an inner circumferential surface of a proximal end side of the solid-state imaging element holder to hold the solid-state imaging element, the inner circumferential surface of a distal end side of the reinforcing member being fitted into an outer circumferential surface of the proximal end side of the solid-state imaging element holder. On a rear end side of the connection portion, the mounting substrate includes a protrusion portion that protrudes outside of the imaging element projection area in a state where the protrusion portion is away from a rear end of the reinforcing member by a specified distance or more. On the rear end side of the connection portion, the plurality of electronic components are mounted on the mounting substrate such that a longitudinal direction of the plurality of electronic components is perpendicular to the optical axis direction, and the plurality of electronic components are arranged away from the rear end of the reinforcing member by the specified distance or more.

In some embodiments, an endoscope device includes an insertion portion provided with an imaging module at a distal end of the insertion portion. The imaging module includes: a solid-state imaging element including a light receiving face for receiving light on a surface of the solid-state imaging element; a glass lid attached to the solid-state imaging element so as to cover the light receiving face of the solid-state imaging element; a mounting substrate including a connection portion which is located inside an imaging element projection area that is a projection area where the solid-state imaging element is projected in an optical axis direction of the solid-state imaging element and which is connected and fixed to a back surface of the solid-state imaging element on a distal end side of the mounting substrate, the mounting substrate on a rear end side being extended in the optical axis direction; a plurality of electronic components mounted on the mounting substrate; a metallic reinforcing member that has a sleeve shape open at both ends and covers the solid-state imaging element and the connection portion of the mounting substrate along the optical axis direction in a state where an inner circumferential surface of the reinforcing member is away from the solid-state imaging element and the mounting substrate; and a solid-state imaging element holder in which an outer circumferential surface of the glass lid is fitted into an inner circumferential surface of a proximal end side of the solid-state imaging element holder to hold the solid-state imaging element, the inner circumferential surface of a distal end side of the reinforcing member being fitted into an outer circumferential surface of the proximal end side of the solid-state imaging element holder. On a rear end side of the connection portion, the mounting substrate includes a protrusion portion that protrudes outside of the imaging element projection area in a state where the protrusion portion is away from a rear end of the reinforcing member by a specified distance or more. On the rear end side of the connection portion, the plurality of electronic components are mounted on the mounting substrate such that a longitudinal direction of the plurality of electronic components is perpendicular to the optical axis direction, and the plurality of electronic components are arranged away from the rear end of the reinforcing member by the specified distance or more.

DETAILED DESCRIPTION

An endoscope device including an imaging unit will be described below as modes for carrying out the invention (hereinafter referred to as “embodiments”). The present invention is not limited by the embodiments. The same reference signs are used to designate the same elements throughout the drawings. The drawings are schematic, and it is be noted that the relation between the thickness and the width of each member and the ratio of the size of each member are different from the reality. The size and the ratio of the same component may be different in different figures.

FIRST EMBODIMENT

FIG. 1is a diagram schematically illustrating an entire configuration of an endoscope system according to a first embodiment of the present invention. As illustrated inFIG. 1, an endoscope device1includes an endoscope2, a universal cord6, a connector7, a light source device9, a processor (control device)10, and a display device13.

The endoscope2captures an in-vivo image of a subject by inserting an insertion portion4into a body cavity of a subject and outputs an imaging signal. A cable bundle in the universal cord6is extended to a distal end of the insertion portion4of the endoscope2and connected to an imaging device provided in a distal end portion31of the insertion portion4.

The connector7is provided to a proximal end of the universal cord6, connected to the light source device9and the processor10, performs specified signal processing on an imaging signal outputted from the imaging device in the distal end portion31connected with the universal cord6, and analog-digital converts (A/D converts) the imaging signal to output the imaging signal as an image signal.

Pulse-shaped white light emitted from the light source device9becomes irradiation light with which an object is irradiated from the distal end of the insertion portion4of the endoscope2through the connector7and the universal cord6. The light source device9is configured by using, for example, a white LED.

The processor10performs specified image processing on the image signal outputted from the connector7and controls the entire endoscope device1. The display device13displays the image signal processed by the processor10.

An operating unit5provided with various buttons and knobs for operating endoscope functions is connected to the proximal end of the insertion portion4of the endoscope2. The operating unit5is provided with a treatment tool insertion opening17from which treatment tools such as an in-vivo forceps, an electrical scalpel, and an inspection probe are inserted into a body cavity of the subject.

The insertion portion4includes the distal end portion31provided with the imaging device, a bending portion32which can be bent in a plurality of directions and is connected to the proximal end of the distal end portion31, and a flexible tube portion33connected to the proximal end of the bending portion32. The bending portion32is bent by an operation of a bending operation knob provided in the operating unit5and can be bent in, for example, four directions of up, down, left, and right, following pulling and relaxing actions of a bending wire inserted into the insertion portion4.

A light guide handle (not illustrated in the drawings) that transmits illumination light from the light source device9is arranged in the endoscope2and an illumination lens (not illustrated in the drawings) is arranged at an emitting end of the illumination light transmitted by the light guide handle. The illumination lens is provided at the distal end portion31of the insertion portion4and the subject is irradiated with the illumination light.

Next, a configuration of the distal end portion31of the endoscope2will be described in detail.FIG. 2is a partial cross-sectional view of the distal end of the endoscope2.FIG. 2is a cross-sectional view taken along a surface which is orthogonal to a substrate surface of an imaging unit provided in the distal end portion31of the endoscope2and which is in parallel with an optical axis direction of the imaging unit.FIG. 2illustrates the distal end portion31of the insertion portion4of the endoscope2and a part of the bending portion32.

As illustrated inFIG. 2, the bending portion32can be bent in four directions of up, down, left, and right following pulling and relaxing actions of a bending wire82inserted into a bending tube81arranged inside a covering tube42described later. An imaging device35is provided inside the distal end portion31extended from the distal end of the bending portion32.

The imaging device35includes a lens unit43and an imaging unit36arranged facing the proximal end of the lens unit43. The imaging device35is attached to the inside of a distal end main body41with an adhesive41a. The distal end main body41is formed of a rigid member for forming an inner space that houses the imaging device35. A proximal end periphery of the distal end main body41is covered with a flexible covering tube42. A member located on the proximal end side with respect to the distal end main body41is formed of a flexible member so that the bending portion32can bend. The rigid portion of the insertion portion4is the distal end portion31in which the distal end main body41is arranged. The length La of the rigid portion is from the distal end of the insertion portion4to the proximal end of the distal end portion main body41. The length Lb corresponds to the outer diameter of the distal end of the insertion portion4.

The lens unit43includes a plurality of objective lenses43a-1to43a-4, a lens holder43bthat holds the objective lenses43a-1to43a-4. The distal end of the lens holder43bis inserted into the distal end main body41and fixed, so that the lens unit43is fixed to the distal end main body41.

The imaging unit36includes a solid-state imaging element44such as CCD or CMOS having a light receiving face that receives light on its surface, a substrate45extending from the solid-state imaging element44, a multi-layer substrate46on which electronic components55to58including a drive circuit of the solid-state imaging element44are mounted, an imaging module40including a glass lid49attached to the solid-state imaging element44so as to cover the light receiving face of the solid-state imaging element44, and a plurality of signal cables48electrically connected to the solid-state imaging element44to drive the solid-state imaging element44. The multi-layer substrate46has the electronic components55to58mounted thereon, so that the multi-layer substrate46functions as a mounting substrate in the claims. The distal end of each signal cable48is electrically and mechanically connected to a cable connection land (not illustrated) provided on the multi-layer substrate46and the substrate45. The plurality of signal cables48are gathered into an electric cable bundle47and extend in the proximal end direction.

The proximal end of each signal cable48extends in the proximal end direction of the insertion portion4. The electric cable bundle47is inserted and arranged in the insertion portion4and extended to the connector7through the operating unit5and the universal cord6illustrated inFIG. 1.

A subject image formed by the objective lenses43a-1to43a-4of the lens unit43is photoelectrically converted by the solid-state imaging element44arranged at an image forming position of the objective lenses43a-1to43a-4and converted into an imaging signal which is an electrical signal. The imaging signal is outputted to the processor10through the signal cables48connected to the substrate45and the multi-layer substrate46and the connector7.

The solid-state imaging element44is attached to the substrate45and the multi-layer substrate46with an adhesive54b. The solid-state imaging element44, a connection portion between the solid-state imaging element44and the substrate45, and a connection portion between the solid-state imaging element44and the multi-layer substrate46are covered by a reinforcing member52formed of a metallic material having a sleeve shape open at both ends. The reinforcing member52is placed away from the solid-state imaging element44and the substrate45in order to avoid influence of static electricity and disturbance noise flowing in from the outside as illustrated by an arrow Ya to the electronic components55to58on the substrate45and a wiring pattern (not illustrated in the drawings) on the substrate45.

The peripheries of the imaging unit36and the distal end portion of the electric cable bundle47are covered by a heat shrinkable tube50to improve durability. In the heat shrinkable tube50, gaps between components are filled with an adhesive resin51. The outer circumferential surface of the reinforcing member52and the inner circumferential surface of a distal end portion of the heat shrinkable tube50are in contact with each other without a gap.

The outer circumferential surface of the glass lid49is fitted into the inner circumferential surface of a proximal end side of a solid-state imaging element holder53, so that the solid-state imaging element holder53holds the solid-state imaging element44attached to the glass lid49. The outer circumferential surface of a proximal end portion of the solid-state imaging element holder53is fitted into the inner circumferential surface of a distal end portion of the reinforcing member52. The outer circumferential surface of a proximal end portion of the lens holder43bis fitted to the inner circumferential surface of a distal end portion of the solid-state imaging element holder53. In a state in which components are fitted to each other in this way, the outer circumferential surface of the lens holder43b, the outer circumferential surface of the solid-state imaging element holder53, and the outer circumferential surface of a distal end portion of the heat shrinkable tube50are fixed to the inner circumferential surface of a distal end portion of the distal end main body41by the adhesive41a.

Next, the imaging module40will be described.FIG. 3is a plan view of the imaging module40and a diagram of the imaging module40as seen from above the substrate45. For the sake of description,FIG. 3illustrates a state in which the reinforcing member52is cut off along a surface in parallel with a surface of the substrate45.FIG. 4is a cross-sectional view taken along line A-A inFIG. 3and a cross-sectional view of the imaging module40taken along a surface which is perpendicular to the surface of the substrate45and in parallel with an optical axis direction of the solid-state imaging element44.FIG. 5is a cross-sectional view taken along line B-B inFIG. 3and a cross-sectional view of the imaging module40taken along a vertical plane to an optical axis direction of the solid-state imaging element44. InFIGS. 3 to 5, an axis corresponding to the optical axis direction of the solid-state imaging element44is defined as an x axis. Further, an axis corresponding to a direction in parallel with the surface of the substrate45and perpendicular to the optical axis direction of the solid-state imaging element44is defined as a y axis. Further, inFIGS. 3 to 5, an axis corresponding to a direction in parallel with a vertical plane to the surface of the substrate45and orthogonal to the optical axis direction of the solid-state imaging element44is defined as a z axis. InFIGS. 3 to 5, the adhesive resin51is omitted.

As illustrated inFIGS. 3 to 5, in the imaging module40, a lower electrode (not illustrated in the drawings) of the solid-state imaging element44and an electrode (not illustrated in the drawings) of the back surface of the substrate45are electrically connected by an inner lead54a. The inner lead54ais bent to an angle of approximately 90° at the distal end of the substrate45and fixed to the solid-state imaging element44and the substrate45by an adhesive.

The substrate45is a rigid substrate and is connected and fixed to the solid-state imaging element44at its distal end portion facing the solid-state imaging element44. The rear end portion of the substrate45is extended and arranged in the optical axis direction of the solid-state imaging element44. The rigid multi-layer substrate46in which a plurality of layers are provided is formed on the surface of the substrate45. In the example ofFIG. 4, five layers are provided as the multi-layer substrate46. A side surface of the distal end of the multi-layer substrate46is connected and fixed to the back surface of the solid-state imaging element44by the adhesive54band the rear end portion of the multi-layer substrate46is extended and arranged in the optical axis direction of the solid-state imaging element44. The rear end portion of the multi-layer substrate46is more extended in the optical axis direction of the solid-state imaging element44than the rear end of the substrate45. The solid-state imaging element44is attached to a part of the upper surface of the substrate45by the adhesive54bon the back surface of the solid-state imaging element44. The substrate45electrically connects the multi-layer substrate46, which is a mounting substrate, with the solid-state imaging element44, so that the substrate45functions as a connection substrate in the claims.

In the reinforcing member52, an opening direction of a hollow portion is in parallel with the optical axis. The reinforcing member52protects the solid-state imaging element44, a connection portion451between the solid-state imaging element44and the substrate45described later, and a connection portion461between the solid-state imaging element44and the multi-layer substrate46described later from an external force by covering them along the optical axis direction. The inner circumferential surface of the reinforcing member52is located at a position away from the solid-state imaging element44, the substrate45, the multi-layer substrate46, and the electronic components55to58by a certain distance N1or more in order to avoid influence of static electricity and disturbance noise to the electronic components55to58on the substrate45and a wiring pattern on the substrate45. The distance N1is set based on electrostatic resistance and disturbance noise tolerance.

The electronic components55to57are mounted on a surface of an uppermost layer of the multi-layer substrate46. The electronic component58is mounted on a back surface of a second layer of the multi-layer substrate46. In the first embodiment, the electronic component55which is the lowest of the plurality of electronic components55to57is arranged at a position closest to the solid-state imaging element44, so that the distance between the inner circumferential surface of the reinforcing member52and the electronic component55is increased to a distance N2(≧N1) by which the electrostatic resistance and the disturbance noise tolerance can be ensured.

On the multi-layer substrate46, a cable connection land59to which a conductor48aof the distal end of the signal cable48is electrically and mechanically connected is provided. The conductor48ais connected to the multi-layer substrate46by being soldered to the cable connection land59. The conductor48ais covered by a covering body48bexcept for the distal end that is connected to the cable connection land59.

In the example ofFIG. 3, three cable connection lands59are provided on the surface of the uppermost layer of the multi-layer substrate46. The cable connection land is also provided on the back surface of the second layer of the multi-layer substrate46(not illustrated in the drawings). All of the cable connection lands59are provided on the proximal end side with respect to the electronic components55to58opposite to the solid-state imaging element44along the optical axis direction. When the cable connection lands are located closer to the solid-state imaging element than the electronic components, the signal cables interfere with each other on the electronic components. As a result, the size of the outer shape of the entire imaging unit may increase. In the first embodiment, the cable connection lands59are provided on the proximal end side, so that the signal cables48do not interfere with each other on the electronic components55to58. Therefore, the size of the outer shape does not increase due to the interference between the signal cables48. When a plurality of cable connection lands59are provided on the same land surface, the plurality of cable connection lands59provided on the land surface are provided to be positioned and aligned on the same straight line in parallel with the y axis.

Here, as illustrated inFIG. 3, the substrate45has the connection portion451that is connected and fixed to the solid-state imaging element44on its distal end side facing the solid-state imaging element44and has protrusion portions452uand452don the rear end side with respect to the connection portion451.

The connection portion451of the substrate45is located inside an imaging element projection area that is a projection area where the solid-state imaging element44is projected in the x axis direction which is the optical axis direction. The connection portion451of the substrate45includes a portion that is connected to the back surface of the solid-state imaging element44by the adhesive54b. The connection portion451is located inside the imaging element projection area where the solid-state imaging element44is projected in the optical axis direction, so that when the connection portion451is seen in a plan view in the z axis direction as inFIG. 3, the width W451in the y axis direction of the projection area in the x axis direction of the connection portion451of the substrate45is smaller than the width W44in the y axis direction of the imaging element projection area.

The protrusion portions452uand452dof the substrate45are formed so as to protrude in the y axis direction from a reinforcing member projection area where the outer circumference of the reinforcing member52is projected in the x axis direction which is the optical axis direction. Therefore, when the substrate45is seen in a plan view in the z axis direction, the width W452in the y axis direction of a projection area where the rear end side of the substrate45including the protrusion portions452uand452dis projected in the x axis direction is greater than the outer diameter W52in the y axis direction of the reinforcing member52.

In the same manner as the substrate45, as illustrated inFIG. 3, the multi-layer substrate46has the connection portion461that is connected and fixed to the back surface of the solid-state imaging element44on its distal end side facing the solid-state imaging element44and has protrusion portions462uand462don the rear end side with respect to the connection portion461.

The connection portion461of the multi-layer substrate46is located inside the imaging element projection area described above. Therefore, when the connection portion461is seen in a plan view in the z axis direction as inFIG. 3, the width W461in the y axis direction of the projection area in the x axis direction of the connection portion461of the multi-layer substrate46is smaller than the width W44in the y axis direction of the imaging element projection area.

The protrusion portions462uand462dof the multi-layer substrate46protrude to the outside of the imaging element projection area in a state in which the protrusion portions462uand462dare away from the rear end of the reinforcing member52by a specified distance N1or more. Specifically, when the protrusion portions462uand462dare seen in a plan view in the z axis direction as inFIG. 3, the protrusion portions462uand462dprotrude upward and downward, respectively, in the y axis direction in an area in the optical axis direction of the reinforcing member52in a state in which the protrusion portions462uand462dare away from the rear end of the reinforcing member52by a specified distance N1or more. Since there are the protrusion portions462uand462d, when the multi-layer substrate46is seen in a plan view in the z axis direction, the width W462in the y axis direction of a projection area where the rear end side of the multi-layer substrate46is projected in the x axis direction is greater than the width W461in the y axis direction of a projection area where the connection portion461of the multi-layer substrate46is projected in the x axis direction. In the example ofFIG. 3, the protrusion portion462uis formed to protrude in the y axis direction from the reinforcing member projection area described above.

Here, an imaging module according to a conventional technique will be described.FIG. 6is a plan view of an imaging module according to a conventional technique and is a diagram of a surface of a substrate seen from above. In a conventional imaging module140illustrated inFIG. 6, the solid-state imaging element44is arranged away from the inner circumferential surface of the reinforcing member52by a certain distance N1in order to ensure the electrostatic resistance and the disturbance noise tolerance. In the same manner, for both of a substrate145and a multi-layer substrate146which are formed into a rectangular shape, the widths of the connection portions are set such that an end portion of each substrate is located away from the inner circumferential surface of the reinforcing member52by the distance N1or more in order to ensure the electrostatic resistance and the disturbance noise tolerance. Both of the substrate145and the multi-layer substrate146extend in the x axis direction while maintaining the widths. In a conventional configuration, in a plan view seen in the z axis direction, the components of the imaging unit including the electronic components and the signal cables in addition to the substrate145and the multi-layer substrate146are arranged in a projection area where the solid-state imaging element44is projected in the x axis direction. Therefore, when the substrate145is seen in a plan view in the z axis direction, the substrate145is formed into a rectangular shape so that the width W145in the y axis direction of a projection area where the substrate145is projected in the x axis direction is smaller than the width W44in the y axis direction of the solid-state imaging element44. In the same manner as the substrate145, the multi-layer substrate146is formed into a rectangular shape so that the width W146in the y axis direction of a projection area where the multi-layer substrate146is projected in the x axis direction is smaller than the width W44.

Reference will be made to a case in which the electronic component57that requires a width with a length of W57(>W44) including a connection land is mounted on the multi-layer substrate146. In the case ofFIG. 6, the width W146in the y axis direction of the multi-layer substrate146is shorter than the length W57. Therefore, the electronic component57cannot be mounted so that the short side direction of the electronic component57is in parallel with the x axis, and thus the electronic component57has to be mounted so that the longitudinal direction of the electronic component57is in parallel with the x axis as illustrated inFIG. 6. Therefore, to place the electronic components55to57including the electronic component57on the multi-layer substrate146, the multi-layer substrate146has to be extended in the x axis direction. Therefore, the length Lap in the x axis direction of the imaging module140becomes longer than that in a case in which the electronic component57is mounted so that the longitudinal direction of the electronic component57is in parallel with the y axis.

Further, in a conventional imaging module, the widths W145and W146in the y axis direction of the substrate145and the multi-layer substrate146are small, so that all of a plurality of connection lands159cannot be arranged on the same straight line in parallel with the y axis. Therefore, as illustrated inFIG. 6, the plurality of connection lands159may have to be arranged by shifting the connection lands159in the x axis direction, so that the length in the x axis direction of the multi-layer substrate146becomes longer. As described above, in the conventional configuration, the multi-layer substrate has to be long in the x axis direction, so that the length in the x axis direction of the distal end main body of the distal end of the insertion portion becomes long. Therefore, there is a limitation for shortening the length of the rigid portion of the distal end of the insertion portion.

On the other hand, in the multi-layer substrate46illustrated inFIG. 3, two protrusion portions462uand462dare formed on the rear end side with respect to the connection portion461. In the same manner, in the substrate45, two protrusion portions452uand452dare formed on the rear end side with respect to the connection portion451. Therefore, the rear end portions of the substrate45and the multi-layer substrate46are largely extended in the y axis direction.

In this way, the multi-layer substrate46is extended in the y axis direction in a portion on the rear end side with respect to the connection portion461. Therefore it is possible to mount the electronic component57on the multi-layer substrate46so that the longitudinal direction of the electronic component57is in parallel with the y axis without extending the multi-layer substrate46in the x axis direction. In other words, it is possible to mount the electronic component57on the multi-layer substrate46so that the short side direction of the electronic component57is in parallel with the x axis. The rear end portion of the multi-layer substrate46is extended in the y axis direction, so that all of the three cable connection lands59can be arranged to be positioned on the same straight line in parallel with the y axis. Therefore, it is possible to minimize the length in the x axis direction required for the cable connection lands59.

Therefore, in the imaging module40, if the outer diameter of the distal end portion of the imaging module is the same as the diameter Lb1of the conventional imaging module140illustrated inFIG. 6, the length La1in the x axis direction of the imaging module40can be smaller than the length Lap in the x axis direction of the conventional imaging module140.

The substrate45and the connection portions451and461of the multi-layer substrate46as illustrated inFIG. 3are arranged within the imaging element projection area and maintain a state in which the substrate45and the connection portions451and461are away from the inner circumferential surface of the reinforcing member52by the distance N1in the same manner as the solid-state imaging element44. Therefore, in the imaging module40, all of the solid-state imaging element44, the substrate45, the multi-layer substrate46, and the electronic components55to58are positioned away from the reinforcing member52by a certain distance N1or more by which the electrostatic resistance and the disturbance noise tolerance can be ensured. Therefore, it is possible to ensure the electrostatic resistance and the disturbance noise tolerance.

Further, as illustrated in an area S10inFIG. 6, conventionally, an area which is an area in the optical axis direction of the reinforcing member52and where the protrusion portions452uand452dof the substrate45and the protrusion portions462uand462dof the multi-layer substrate46are located is a dead space in which no member is arranged and which is only filled with an adhesive resin. Therefore, even when the protrusion portions462u,462d,452u, and452dare provided to the multi-layer substrate46and the substrate45, it does not affect the arrangements and the operations of other members.

In this way, in the first embodiment, the rear end portions of the substrate45and the multi-layer substrate46are extended by effectively using a space in the optical axis direction of the reinforcing member52, which is conventionally a dead space, so that it is possible to arrange the electronic components55to58and the cable connection lands59without extending the multi-layer substrate46in the optical axis direction.

In the first embodiment, as in an imaging module40A illustrated inFIG. 7, protrusion portions462Au and462Ad of a multi-layer substrate46A may be positioned inside the reinforcing member projection area described above. In the same manner, protrusion portions452Au and452Ad of a substrate45A may be positioned inside the reinforcing member projection area. Therefore, in the imaging module40A, when the imaging module40A is seen in a plan view in the z axis direction, the width W462A in the y axis direction of a projection area where the rear end side of the multi-layer substrate46A is projected in the x axis direction and the width W452A in the y axis direction of a projection area where the rear end side of the substrate45A is projected in the x axis direction are smaller than or equal to the outer diameter W52of the reinforcing member52. Further, when the electronic components55to58mounted on the imaging module40A and the signal cables48connected to the imaging module40A are arranged inside the reinforcing member projection area, the heat shrinkable tube50covers the entire imaging unit while maintaining substantially the same inner diameter as the outer diameter W52of the reinforcing member52regardless of the shapes of the substrate45A and the multi-layer substrate46A. Therefore, in this case, the outer diameter of the imaging unit including the imaging module40A is substantially the same from the distal end to the rear end along the optical axis direction, so that components can be easily installed.

As illustrated in an imaging module40B inFIG. 8, the protrusion portions452Ad and462Ad are provided in only the area R2located lower in the y axis direction of a substrate45B and a multi-layer substrate46B, and a space S10B including the other area R1including no protrusion portion may be used for other members.

In addition to extending the rear end portions of the substrate and the multi-layer substrate along the y axis direction as in the imaging modules40,40A, and40B illustrated inFIGS. 3, 7, and 8, as illustrated in an imaging module40C inFIG. 9, protrusion portions may be formed by thickening the rear end portion of the multi-layer substrate46in the z axis direction that is a lamination direction of the multi-layer substrate46. In a multi-layer substrate46C constituting the imaging module40C, a seventh layer46C-7and an eighth layer46C-8are formed on the upper surface of the rear end portion of the multi-layer substrate46and a first layer46C-1and a second layer46C-2are formed on the lower surface of the rear end portion of the multi-layer substrate46, so that the rear end portion is thicker than the distal end portion. Therefore, as illustrated inFIG. 9, when a cross-section of the imaging module40C taken along a surface which is perpendicular to the surface of the substrate45and in parallel with the optical axis direction of the solid-state imaging element44is seen in a plan view in the y axis direction, the first layer46C-1of the multi-layer substrate46C becomes a protrusion portion that protrudes downward in the z axis direction from the imaging element projection area described above. In this case, the size T462C in the z axis direction of a projection area in the x axis direction of the rear end side of the multi-layer substrate46C is greater than the size T461C of a projection area in the x axis direction of the connection portion461on the distal end side of the multi-layer substrate46C, so that it is possible to secure a wiring space in the rear end portion of the multi-layer substrate46C. Further, when the mounting substrate includes electronic components55,56,57C, and58in addition to the multi-layer substrate46C, it is possible to configure the mounting substrate so that a portion which is located in a rear end portion of the multi-layer substrate46C and which includes the electronic components57C and58is projected in the x axis direction and the size T570in the z axis direction of the projection area is greater than the size T44in the z axis direction of the imaging element projection area. The size T57C may be set to smaller than or equal to the outer diameter W52of the reinforcing member52and the outer diameter of the imaging unit including the imaging module40C may be set to substantially the same diameter from the distal end to the rear end. As described above, in the first embodiment, when the protrusion portion provided in the rear end side of the multi-layer substrate is formed to protrude to the outside of the imaging element projection area, the protrusion portion may protrude in any direction of the z axis direction and the y axis direction.

SECOND EMBODIMENT

Next, a second embodiment will be described.FIG. 10is a partial cross-sectional view illustrating an imaging unit according to the second embodiment.FIG. 10is a cross-sectional view of an imaging unit taken along a surface perpendicular to a surface of a light receiving area of an imaging element included in the imaging unit according to the second embodiment.

As illustrated inFIG. 10, an imaging unit236according to the second embodiment includes a multi-layer substrate246in which eight layers are provided on the proximal end side. On an upper side and back side of the multi-layer substrate, the electronic components55to58are mounted and cable connection lands (not illustrated in the drawings) to which conductors481aand482aof the signal cables48are connected are provided on the proximal end side.

As illustrated inFIG. 10, the electronic components55to57are mounted on an upper surface Pt246-5of a fifth layer246-5of the multi-layer substrate246. On an upper surface Pt246-8of an uppermost eighth layer246-8of the multi-layer substrate246, a cable connection land to which the conductor481aof the signal cable48is connected is provided. Therefore, the upper surface Pt246-8which is a land surface on which the cable connection land is provided is a surface different from the upper surface Pt246-5which is a mounting surface of the electronic components55to57. The upper surface Pt246-8which is the land surface corresponds to a surface located upward away in the z axis direction from the upper surface Pt246-5which is the mounting surface by a distance corresponding to three layers. Therefore, the upper surface Pt246-8which is the land surface is provided at a position vertically away from the upper surface Pt246-5which is the mounting surface by the level distance.

The height of the upper surface of the conductor481ais set to equal to the height of the upper surface of the electronic component57mounted closest to the signal cable having the conductor481a. In the case ofFIG. 10, the thickness Ht246of the multi-layer substrate246from the mounting surface Pt246-5is set such that the height of the upper surface Pt57of the electronic component57mounted closest to the signal cable having the conductor481ais substantially equal to the height of the upper surface Pt481of the conductor481aconnected to the cable connection land on the eighth layer246-8. In other words, the thickness Ht246of the multi-layer substrate246from the mounting surface Pt246-5is set such that the distance Ht57between the mounting surface Pt246-5and the upper surface Pt57of the electronic component57in the z axis direction is nearly equal to the distance Ht48between the mounting surface Pt246-5and the upper surface Pt481of the conductor481ain the z axis direction.

The same goes for a case in which the electronic components are mounted on the back surface of the multi-layer substrate246. As an example of this case, the electronic component58mounted on a lower surface Pb246-2of a second layer246-2of the multi-layer substrate246and the conductor482aof the signal cable connected to the connection land on a lower surface Pb246-1of a first layer246-1of the multi-layer substrate246will be described. Also in this case, the thickness Hb246of the multi-layer substrate246from the mounting surface Pb246-2is set such that the height of the lower surface Pb58of the electronic component58mounted closest to the signal cable having the conductor482ais substantially equal to the height of the lower surface Pb482of the first layer246-1which is the land surface. In other words, the thickness Hb246of the multi-layer substrate246from the mounting surface Pb246-2is set such that the distance Hb58between the mounting surface Pb246-2and the lower surface Pb58of the electronic component58in the z axis direction is substantially equal to the distance Hb48between the mounting surface Pb246-2and the lower surface Pb482of the conductor482ain the z axis direction. As described above, in the second embodiment, the distance between a non-contact surface opposite to a land surface of the cable connection land of the signal cable48and the mounting surface of the electronic components in the vertical direction to the mounting surface is set to equal to the distance between the electronic component mounted closest to the signal cable and the mounting surface in the vertical direction to the mounting surface. The distance between the non-contact surface opposite to the land surface of the cable connection land of the signal cable48and the mounting surface of the electronic components in the vertical direction to the mounting surface and the distance between the electronic component mounted closest to the signal cable and the mounting surface in the vertical direction to the mounting surface need not be completely equal to each other, but may be within an allowable error range considering various variations such as variation of thickness of the multi-layer substrate, variation of the size of each member, variation of mounting accuracy, variation of the amount of solder applied per time, and the amount of deviation of a soldering iron that comes into contact.

In the conventional configuration in which the cable connection land and the mounting surface are provided on the same plane, to prevent a clearance between an electronic component and the cable connection land from being short-circuited due to solder flowing from the cable connection land to the mounting surface, the clearance between the electronic component and the cable connection land is required to be large. As a result, in the conventional configuration, the length in the x axis direction of the multi-layer substrate has to be long, so that there is a problem that the length of the rigid portion of the distal end of the insertion portion of the endoscope is long.

On the other hand, in the imaging unit236in the second embodiment, the number of layers of the multi-layer substrate is increased in an area where the cable connection land is placed, so that a level difference is formed between the electronic component and the cable connection land and a long distance is provided between the mounting surface and the cable connection land. Therefore, in the imaging unit236, even when solder61flows out as illustrated by an arrow Y10inFIG. 11, the distance for the solder61to reach the electronic component is long, so that a short-circuit between the conductor481aconnected to the cable connection land and the electronic component57is more difficult to occur than in the conventional configuration.

In the conventional configuration in which the cable connection land and the mounting surface are provided on the same surface, a distal end of a soldering iron comes into contact with the electronic component in a soldering process of the signal cable, so that the clearance between the electronic component and the cable connection land is required to be large.

On the other hand, in the imaging unit236in the second embodiment, the number of layers on the proximal end side of the multi-layer substrate246is increased and the height of the land surface of the cable connection land is raised so that the height of the upper surface Pt481of the conductor481ais the same as the height of the upper surface Pt57of the electronic component57. As a result, in the imaging unit236, there is not the electronic component57in a distal end direction of a soldering iron60, so that the soldering iron60does not hit the electronic component57.

Therefore, in the imaging unit236, even when a distance N10tbetween the electronic component57and an end portion of the eighth layer246-8on which the cable connection land is formed is small, a short-circuit due to flowing out of the solder61and an interference of the soldering iron60do not occur. In the same manner, on the back surface, even when a distance N10bbetween the electronic component58and an end portion of the first layer246-1on which the cable connection land is formed is small, the height of the lower surface Pb482of the conductor482ais substantially the same as the height of the lower surface Pb58of the electronic component58and the distance between the mounting surface and the cable connection land is long, so that a short-circuit due to flowing out of the solder61and an interference of the soldering iron60do not occur. Therefore, in the second embodiment, it is possible to reduce a length La10of the rigid portion of the imaging unit236and reduce the size of the imaging unit236itself, and accordingly, it is possible to reduce the length of the rigid portion of the distal end of the insertion portion of the endoscope.

In the second embodiment, as in an imaging unit236A illustrated inFIG. 12, in a multi-layer substrate246A, a metallic component261is provided on the upper surface Pt246-5of the fifth layer246-5which is the mounting surface and a cable connection land is provided on the upper surface P261of the metallic component261, so that the height Ht48A of the upper surface Pt481A of the conductor481aconnected to the cable connection land may be raised to be substantially the same as the height of the upper surface Pt57of the electronic component57as illustrated by an arrow Y11. In this case, the number of layers of the multi-layer substrate246A need not be increased. Therefore, the manufacturing process can be simplified and the cost reduction can be achieved.

As in an imaging unit236B illustrated inFIG. 13, depending on the thickness of a sixth layer246B-6to an eighth layer246B-8of a multi-layer substrate246B, the height Ht48B of the upper surface of the conductor481amay be adjusted to be the same as the height of the upper surface Pt57of the electronic component57as illustrated by an arrow Y12by connecting the conductor481ato the cable connection land through a spacer262.FIG. 14is a right side view of the spacer262. As illustrated inFIG. 14, the spacer262has a through-hole262H, and the conductor481ais inserted into the through-hole262H. As illustrated inFIGS. 12 to 14, in the second embodiment, the height of the conductor481amay be raised by mounting a metallic component on the surface of the substrate of a substrate body or a surface of any one of the layers of the multi-layer substrate and providing a cable connection land on the surface of the metallic component.

Further, as in an imaging unit236C inFIG. 15, a groove263may be provided between an electronic component257and the cable connection land59.FIG. 16is a cross-sectional view taken along line C-C inFIG. 15. As illustrated inFIG. 16, the groove263is provided in a fifth layer246C-5of a multi-layer substrate246C and the solder61is collected in the groove263, so that the solder61does not flow to the electronic component257. In this way, a large distance between the electronic component257and the cable connection land59may be ensured by providing the groove263. To prevent a short-circuit between the electronic component and the cable connection land, a concave portion that can collect the solder61only has to be provided between the mounting surface of the electronic component257and the land surface of the cable connection land59on the upper side of the multi-layer substrate, so that it is not necessarily required to form the groove263over the entire length in the y axis direction of the multi-layer substrate246C.

As in the imaging unit236C inFIG. 15, all of the three cable connection lands may be placed within a projection area where the electronic component257and two component connection lands57R of the electronic component257are projected in the x axis direction. Alternatively, as in an imaging unit236D inFIG. 17, one cable connection land259D of the three cable connection lands on a multi-layer substrate246D may be placed outside a projection area where the electronic component257and the component connection lands57R are projected in the x axis direction. In the same manner as in the first embodiment, in the second embodiment, a plurality of cable connection lands are provided on the same land surface, the plurality of cable connection lands provided on the land surface are orthogonal to the longitudinal direction of the multi-layer substrate which is the mounting substrate, and the plurality of cable connection lands are located on the same straight line in parallel with the land surface.

FIG. 18is a cross-sectional view taken along line D-D inFIG. 17. As illustrated inFIG. 18, all of the upper surfaces of the three conductors48aare arranged to be the same height as the upper surface of the electronic component257in both cases of the case in which all of the cable connection lands are placed within the projection area where the electronic component257and the component connection lands57R are projected in the x axis direction and the case in which one cable connection land259D is placed at a position outside the projection area where the electronic component257and the component connection lands57R are projected in the x axis direction. In this case, all of the upper surfaces of the three conductors48aare arranged to be the same height, so that it is possible to efficiently perform soldering on all of the three conductors48aat the same time by using a pulse heat tool264.

Further, as in an imaging unit236E inFIG. 19, when connecting conductors48a-1to48a-3having a diameter different from one another, the thickness of the layer of a multi-layer substrate246E immediately below each conductor may be adjusted so that the heights of the upper surfaces of the conductors48a-1to48a-3are arranged to be the same height. For example, for the multi-layer substrate246E immediately below the conductor48a-1having the smallest outer diameter, the number of layers is set to nine. For the multi-layer substrate246E immediately below the conductor48a-2having the second smallest outer diameter after the conductor48a-1, the number of layers is set to eight. For the multi-layer substrate246E immediately below the conductor48a-3having the largest outer diameter, the number of layers is set to seven. To perform soldering at the same time by using the pulse heat tool when the heights of the conductors are uneven, it is required to form unevenness corresponding to the heights of the conductors in a tool surface of the pulse heat tool. On the other hand, in the imaging unit236E, the multi-layer substrate246E is formed to vary the thickness of the layers according to the diameters of the signal cables so that the distance between the non-contact surface opposite to the cable connection land and the mounting surface of the electronic components in the vertical direction to the mounting surface is equal for each signal cable. As a result, the imaging unit236E has a plurality of the land surfaces where the distance to the mounting surface in the vertical direction to the mounting surface is set such that the distance between the non-contact surface opposite to the cable connection land and the mounting surface of the electronic components in the vertical direction to the mounting surface is equal for each signal cable. Therefore, it is possible to perform soldering by using only the pulse heat tool264in which a tool surface P264with which the conductor comes into contact is still flat.

In the second embodiment, a case is mainly described where when the mounting surface is an upper surface, the cable connection land is formed on a surface higher than the mounting surface of electronic components so that the cable connection land can be provided at a position away from the mounting surface of electronic components in the vertical direction to the mounting surface. However, when the cable connection land is formed on a surface different from the mounting surface of electronic components from among the surfaces of the substrate body, it is possible to prevent the solder from flowing into the electronic components, so that the surface on which the cable connection land is provided may be formed on a surface lower than the mounting surface of electronic components. In the first and the second embodiments, an imaging unit including a rigid substrate has been described. However, the substrate may be, of course, a flexible printed circuit board. In the first and the second embodiments, an example where electronic components are mounted on a multi-layer substrate has been described. However, the substrate on which the electronic components are mounted is not limited to a multi-layer substrate in which a plurality of layers are provided, but may be a rigid substrate having a single layer.

An imaging unit including:

a solid-state imaging element including a light receiving face for receiving light;

a mounting substrate provided extending from the solid-state imaging element in an optical axis direction of the solid-state imaging element and configured to be electrically connected to the solid-state imaging element;

an electronic component mounted on an upper side of the mounting substrate and including a drive circuit for the solid-state imaging element; and

a signal cable configured to be electrically connected to the electronic component, wherein

on the upper side of the mounting substrate, provided are a mounting surface on which the electronic component is mounted and a land surface which is different from the mounting surface and on which a cable connection land to which the signal cable is configured to be electrically connected is provided.

The imaging unit according to appendix 1, wherein

the land surface is provided at a position away from the mounting surface by a level difference portion in a vertical direction to the mounting surface.

The imaging unit according to appendix 1 or 2, wherein

a distance between the mounting surface and a non-contact surface of the signal cable on an opposite side of the land surface in a vertical direction to the mounting surface is equal to a distance of the electronic component mounted closest to the signal cable from the mounting surface in the vertical direction to the mounting surface.

The imaging unit according to any one of appendices 1 to 3, wherein

the cable connection land is provided on a proximal end side with respect to the electronic component opposite to the solid-state imaging element along the optical axis direction.

The imaging unit according to any one of appendices 1 to 4, wherein

on the mounting surface of the mounting substrate, a metallic component is provided, and

the cable connection land is provided on a surface of the metallic component.

The imaging unit according to any one of appendices 1 to 5, wherein

on the upper side of the mounting substrate, a concave portion is provided between the mounting surface and the land surface.

The imaging unit according to any one of appendices 1 to 6, further including additional one or more cable connection lands, wherein

at least one of the cable connection land and the additional one or more cable connection lands is provided at a position outside a projection area where the electronic component and a component connection land on which the electronic component on the mounting surface is mounted are projected in the optical axis direction.

The imaging unit according to any one of appendices 1 to 7, wherein

the cable connection land and additional one or more cable connection lands are provided on the same land surface, wherein

the cable connection land and the additional one or more cable connection lands on the land surface are orthogonal to a longitudinal direction of the mounting substrate and are arranged and positioned on a same straight line in parallel with the land surface.

The imaging unit according to appendix 7 or 8, wherein

a distance between the mounting surface and a non-contact surface of the signal cable on an opposite side of the land surface in a vertical direction to the mounting surface is equal for each signal cable.

The imaging unit according to appendix 9, wherein

the mounting substrate has the land surface and additional one or more land surfaces in which a distance to the mounting surface in the vertical direction to the mounting surface is set according to a signal cable diameter such that the distance between the mounting surface and the non-contact surface of the signal cable on the opposite side of the land surface in the vertical direction to the mounting surface is equal for each signal cable.

An endoscope device including an insertion portion provided with the imaging unit according to any one of appendices 1 to 10 at a distal end of the insertion portion.

According to some embodiments, it is possible to provide an imaging module and an endoscope device in which a connection land and an electronic component can be arranged without extending a mounting substrate in an optical axis direction.