This application claims priority to Japanese Application No, 2018-238327, filed on Dec. 20, 2018, which application is incorporated herein by reference in its entirety.
The present disclosure relates to a cable assembly including an electronic device such as a sensor, a cable connected to the electronic device, and a cable holder for supporting the electronic device and the cable; a cable holder which is fixed to an electronic device in order to connect a cable to the electronic device and supports the cable; and a production method for a cable assembly for connecting a cable to an electronic device using a cable holder.
Conventionally, when connecting a signal or power cable to a sensor such as an individual imaging element via a circuit board, there is a known tip part of an electronic endoscope which enables a connection operation to be performed while the length of a solder margin is stably secured, and which enables a signal line connection to be soldered to the circuit board with sufficient strength for example, see Patent Document 1.
Specifically, Patent Document 1 discloses a tip part of an electronic endoscope in which the tip portion of a signal line drawn in a direction facing a substrate surface of a circuit board from a tip of a signal cable inserted into an insertion part is connected to a connection terminal part provided on an outer edge part of the circuit board, wherein the connection terminal part of the circuit board is formed with a shape that is a groove shape into which the tip portion of the signal line is fitted, the shape having an abutting surface at which the tip surface of the signal line abuts.
In the configuration of Patent Document 1, a signal line of the signal cable is soldered to the circuit board, and the signal cable and an individual imaging element are electrically connected via the circuit board. Electronic components are disposed on the circuit board, and the circuit board and the individual imaging element are further connected by leads so as to electrically connect the signal cable and the individual imaging element.
Such a configuration is relatively large, as the electronic components are disposed on the circuit board, however when the individual imaging element is a very small electronic device such as a chip-like CMOS (Complementary Metal-Oxide Semiconductor) image sensor, the circuit board must be made small in accordance with the sensor or the like. This leads to a problem in that it is difficult to connect the signal cable to a sensor or the like with a similar means.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2006-68057
Therefore, the present disclosure was conceived in light of the problems described above, and an object thereof is to provide a cable assembly, a cable holder, and a production method for a cable assembly which, even when attempting to connect a signal or power cable to a small electronic device such as a chip-type sensor, for example, can facilitate the connection of the cable to the electronic device and secure sufficient strength to fix the electronic device and the cable.
The present disclosure was proposed to achieve the object described above, and one mode of the present disclosure is a cable assembly including an electronic device, a cable connected to the electronic device, and a cable holder for supporting the electronic device and the cable, Herein, the electronic device includes a terminal array surface on which terminals to be electrically connected to the cable are arranged; the cable holder includes a connection surface facing the terminal array surface, and a side surface having a connection groove formed with an opening corresponding to the array positions of the terminals on the connection surface so as to support the cable in a direction intersecting the terminal array surface, and the connection groove is subjected to surface treatment to allow an electrical connection with a core wire of the cable; the terminals are provided with a convex conductive body housed in the connection groove; an adhesive layer is provided between the terminal array surface and the connection surface; and the cable holder is translucent.
Another mode of the present disclosure is a cable holder including: a connection surface which is a plane facing a terminal array surface on which terminals of an electronic device to which a cable is to be connected are arranged; a cable extension surface from which the signal cable extends; and a side surface connecting the connection surface and each side of the cable extension surface. Herein, the side surface includes a connection groove formed continuously so as to open toward the side surface side by forming an opening in the connection surface and the cable extension surface; and the holder is translucent.
Yet another mode of the present disclosure is a production method for a cable assembly. This method includes: arranging a plurality of terminal array surfaces on which terminals of an electronic device are arranged so as to face upward; applying a photocurable adhesive to locations other than the terminals of the terminal array surface lower than convex conductive bodies formed on the terminals; mounting a translucent cable holder so as to spread the applied photocurable adhesive to the back surface; adhesively fixing a sensor and the cable holder by irradiating light from an upper surface on the cable holder side; installing a core wire of the cable in a connection groove formed in the cable holder; and connecting the core wire, the connection groove, and the terminals.
With the present disclosure, it is possible to provide a cable assembly, a cable holder, and a production method for a cable assembly which, even in the case of a small electronic device such as a chip-type sensor, for example, can facilitate the connection of a cable to the electronic device and secure sufficient strength to fix the electronic device and the cable.
Embodiments of the present disclosure will be described in detail hereinafter with reference to the drawings.
Note that expressions indicating directions such as up, down, left, right, front, and back used to described the embodiments are not absolute but rather are relative directions, and although the expressions are appropriate when each part is in the position illustrated in the drawings, the directions should be interpreted differently in accordance with any change in position when the position changes.
First, the overall configuration of a cable assembly 10 of a first embodiment will be described with reference to
As an example of an electronic device in the present application, the sensor 20 is, for example, a thin, rectangular plate-shaped chip-type sensor, and four terminals 22 (a conduction pattern, PAD, or the like formed by plating or the like) to which core wires 42 of cables 40 described below are connected are formed on a surface serving as a cable connection side of a sensor body 21 (right side in
The cable holder 30 is formed in a rectangular parallelepiped shape including a rectangular connection surface 31a facing the terminal array surface 21a of the sensor, a cable extension surface 31b which is parallel with and of the same shape as the connection surface 31a, a pair of first side surfaces 31c connecting the parallel sides of the connection surface 31a and the cable extension surface 31b, and a pair of second side surfaces 31d connecting the other parallel sides.
The pair of first side surfaces 31c has penetrating connection grooves 32 extending from the connection surface 31a toward the cable extension surface 31b on the opposite side (cable 40 side). The connection grooves 32 are provided at positions corresponding to the array of the terminals 22, and open at the connection surface 31a in alignment with the positions of the terminals 22 of the sensor 20. In this embodiment, the drawings illustrate a mode in which two of each are provided on the pair of first side surfaces 31c on the upper and lower sides.
The connection grooves 32 are formed in a groove shape so that the bottom surface side thereof is opened to the first side surface 31c side with a cylindrical wall surface of a prescribed diameter (L1 in
In this embodiment, the surfaces of the terminals 22 not covered by the resist 25 and the solder balls 23 are formed with the same diameter L2.
As described below, the cable holder 30 is preferably formed from a translucent, UV-permeable material (for example, a material that transmits light such as UV-permeable glass). In this case, since the cable holder 30 is formed from an insulating body, the surfaces of the connection grooves 32 are plated with gold or the like to ensure conductivity and solderability. Each connection groove 32 is electrically independent from the other.
The cable 40 has a cable sheath 41 and a core wire 42 for powering the inside thereof. The sensor 20 side—that is, the end side—of the core wire 42 is exposed so as to be soldered and joined to the terminals 22 of the sensor 20 and the connection grooves 32 of the cable holder 30.
By adhering using the UV curing adhesive 24, the fixing of the cable holder 30 and the sensor 20 can be achieved with UV irradiation without heating, which is effective to minimize the effects of heat due to soldering or the like on the sensor 20.
The core wire 42 of the cable 40 is mounted in the connection groove 32 in a state in which the tip abuts the solder ball 23 inside the connection groove 32 of the cable holder 30, and is joined to the terminal 22 of the sensor 20 and the plating of the connection groove 32 of the cable holder 30 by soldering so that the sensor 20 and the cable 40 are electrically conductive with one another.
In this way, by assembling the sensor 20 and the cable 40 via the cable holder 30 in which the connection grooves 32 are formed, the connection of the cable in a direction intersecting the terminal array surface 21a of the sensor 20—for example, a direction orthogonal to the terminal array surface 21a—can be achieved easily, and by soldering to the connection grooves 32 of the cable holder 30, the strength with which the sensor 20 and the cable 40 are fixed can be sufficiently ensured.
Next, the details of the sensor 20 and the cable holder 30 will be described with reference to
As illustrated in
As illustrated in
As illustrated in
As illustrated in
The fixing of the sensor 20 and the cable holder 30 will be described further with reference to
The UV curing adhesive 24 is applied to the central portion of the terminal array surface 21a of the sensor body 21, however, as illustrated in
Next, the cross-sectional structure after the cable holder 30 is mounted on the terminal array surface 21a of the sensor 20 will be described using
Such a solder ball 23 prevents the terminal 22 from being covered by the UV curing adhesive 24 as a conductive body formed with a convex shape from the terminal 22, and ensures the electrical connection between the core wire 42 and the terminal 22.
When such a convex conductive body is formed from a solder ball 23, the solder ball 23 melts and becomes integral with the solder of the connection groove 32 after soldering, however, the tip of the core wire 42 is connected by soldering while separated from the upper surface of the terminal 22 by the height of the solder ball 23, and solder can be added to the connection groove 32 when the amount of solder of the solder ball 23 is insufficient.
The UV curing adhesive that is pushed out between the terminal array surface 21a and the connection surface 31a forms an adhesive layer for fixing the sensor 20 and the cable holder 30.
As illustrated in
In the production process of the cable assembly 10, when the core wire 42 of the cable 40 is soldered to the plating of the connection groove 32, a pair of first side surfaces 31c of the parallel, flat cable holder 30 are pressed by a jig from the outside so that the core wire 42 does not protrude from the connection groove 32. The cable holder 30, however, is sized to be smaller than the sensor 20 and to not protrude from the sensor 20 so as to maximally use the space around the sensor 20.
In addition, in the production process of the cable assembly 10, when the cable holder 30 is mounted on the sensor 20, the connection surface 31a and the cable extension surface 31b of the cable holder 30 are formed in parallel and in a flat manner, so the cable holder 30 can be easily handled with a suction chuck jig such as a chip mounting machine, which makes it possible to improve productivity.
Since the UV curing adhesive 24 is applied to the terminal array surface 21a of the sensor 20 lower than the solder balls 23, when the cable holder 30 is mounted on the sensor 20, as illustrated in
Next, a cable assembly 10 of a second embodiment will be described with reference to
As illustrated in
When the cable holder 30 is mounted on the sensor 20, the UV curing adhesive 24 flows into the second adhesive groove 33b (also the same for the first adhesive groove 33a), as illustrated in
Further, since the contact area of the UV curing adhesive 24 and the cable holder 30 is increased by the adhesive groove 33, the adhesive force between the cable holder 30 and the sensor 20 increases.
Next, a cable assembly 10 of a third embodiment will be described with reference to
As illustrated in
The fixing of the sensor 20 and the cable holder 30 will be described using
The width (diameter) L1 of the connection grooves 32 of the cable holder 30 is set to be greater than the width (diameter) L3 of the bumps 26 of the sensor 20 so that when the cable holder 30 is mounted on the sensor 20, the bumps can be smoothly and easily housed in the connection grooves 32.
When the cable holder 30 is mounted on the sensor 20, as in the first embodiment, the upper parts of the bumps 26 are housed in the connection grooves 32 before the connection surface 31a of the cable holder 30 comes into contact with the UV curing adhesive 24. Therefore, in a cross-sectional view, as illustrated in
Note that in
First, the method for fixing the cable holder 30 to the sensor is as follows. As a first step, a plurality of terminal array surfaces 21a of the sensor 20 are arranged in an upward orientation, and the UV curing adhesive 24 is applied lower than the solder balls 23 or bumps 26 so as to mount the cable holder 30. As a second step, the cable holder 30 is irradiated with UV from the upper surface on the cable holder 30 side so as to adhere and fix the sensor 20 and the cable holder 30. In this process, operations can be performed with high precision and in large volumes using a suction chuck jig of a chip mounting machine.
Next, as a third step, the sensor 20, where the cable holder 30 is fixed, is fixed to the jig. As a fourth step, the cable sheath 41 of the cable 40 is stripped to expose the core wire 42. As a fifth step, the core wire 42 of the cable 40 is inserted into the connection groove 32 of the cable holder 30 and is sandwiched by a flat plate-shaped jig so that the core wire 42 does not deviate from the connection groove 32 from both outer sides of the first side surface 31c. As a sixth step, solder is applied to the connection groove 32 of the cable holder 30. As a seventh step, the solder is melted by reflow so as to electrically connect and fix the sensor 20, the cable holder 30, and the cable 40.
Preferred embodiments of the present disclosure have been described in detail, however, the present disclosure is not limited to the embodiments described above, and various modifications and changes are possible within the scope of the gist of the present disclosure described in the scope of the patent claims.
For example, in the embodiments described above, a mode in which four cables 40 are separately inserted into the connection grooves 32 of the cable holder 30 was described, however, a plurality of cables 40 may be bundled together and inserted into the connection grooves 32 simultaneously, for example. This makes it possible to simplify the connection of the cables 40.
In addition, although four cables 40 were described in the above embodiments, in
Further, although the shape of the sensor 20 was described as rectangular and the shape of cable holder 30 was described as having a substantially rectangular profile corresponding thereto, when a cylindrical sensor 20 is used, for example, the profile of the cable holder 30 may be curtailed to form an arc-shaped profile so as not to protrude from the sensor 20. This makes it possible to smoothly pass the sensor 20 and the cable holder 30 into the cylinder.
In addition, although the cable connection direction was described as a direction orthogonal to the terminal array surface 21a in the above embodiments, the direction is not necessarily orthogonal, and the direction of the connection grooves can be variously changed so that the cable can also be applied in a direction intersecting the terminal array surface 21a.
Further, although the adhesive was a UV curing adhesive and the irradiated light was UV in the embodiments described above, the present disclosure is not limited to this case, and visible light curing may also be used.
Number | Date | Country | Kind |
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2018-238327 | Dec 2018 | JP | national |