Image capturing module, endoscope and method of manufacturing image capturing module

An image capturing module includes a flexible circuit board and an image sensor. The flexible circuit board includes a plurality of first pads and a plurality of second pads. The first pads are disposed on a first surface of the flexible circuit board and the second pads are disposed on a second surface of the flexible circuit board, wherein the first surface is opposite to the second surface. The image sensor is disposed on the first surface. A distance between the image sensor and the first pads is identical to a distance between the image sensor and the second pads. The flexible circuit board is folded to align and weld the first pads with the second pads, such that a light receiving surface of the image sensor is perpendicular to surfaces of the first and second pads.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an image capturing module and, more particularly, to an image capturing module adapted to an endoscope and a method of manufacturing the image capturing module.

2. Description of the Prior Art

Endoscope is a medical instrument that enters a human body through various channels to observe internal conditions of the human body. In general, the endoscope comprises an elongated tube for being inserted into the human body and an image sensor disposed in the elongated tube for capturing inside images of the human body. The thicker the tube is, the more uncomfortable the human body feels. To reduce the thickness of the tube, a micro image sensor has been developed. The micro image sensor is disposed in the elongated tube by a flexible circuit board. However, it is difficult to dispose such a micro image sensor with small dimensions (e.g. 650 μm*650 μm*1158 μm) on a corresponding flexible circuit board.

SUMMARY OF THE INVENTION

The invention provides an image capturing module adapted to an endoscope and a method of manufacturing the image capturing module, so as to solve the aforesaid problems.

According to an embodiment of the invention, an image capturing module comprises a flexible circuit board and an image sensor. The flexible circuit board comprises a plurality of first pads and a plurality of second pads. The first pads are disposed on a first surface of the flexible circuit board and the second pads are disposed on a second surface of the flexible circuit board, wherein the first surface is opposite to the second surface. The image sensor is disposed on the first surface. A distance between the image sensor and the first pads is identical to a distance between the image sensor and the second pads. The flexible circuit board is folded to align and weld the first pads with the second pads, such that a light receiving surface of the image sensor is perpendicular to surfaces of the first and second pads.

According to another embodiment of the invention, an endoscope comprises a tube and an image capturing module. The image capturing module is disposed in the tube. The image capturing module comprises a flexible circuit board and an image sensor. The flexible circuit board comprises a plurality of first pads and a plurality of second pads. The first pads are disposed on a first surface of the flexible circuit board and the second pads are disposed on a second surface of the flexible circuit board, wherein the first surface is opposite to the second surface. The image sensor is disposed on the first surface. A distance between the image sensor and the first pads is identical to a distance between the image sensor and the second pads. The flexible circuit board is folded to align and weld the first pads with the second pads, such that a light receiving surface of the image sensor is perpendicular to surfaces of the first and second pads.

According to another embodiment of the invention, a method of manufacturing an image capturing module comprises steps of forming a plurality of first pads and a plurality of second pads on a flexible circuit board, wherein the first pads is disposed on a first surface of the flexible circuit board, the second pads is disposed on a second surface of the flexible circuit board, and the first surface is opposite to the second surface; disposing an image sensor on the first surface, wherein a distance between the image sensor and the first pads is identical to a distance between the image sensor and the second pads; folding the flexible circuit board to align the first pads with the second pads and make a light receiving surface of the image sensor perpendicular to surfaces of the first and second pads; and welding the first pads with the second pads.

As mentioned in the above, the invention disposes the image sensor on the flexible circuit board first and then folds the flexible circuit board to weld the first pads with the second pads thereon. At this time, the light receiving surface of the image sensor is perpendicular to surfaces of the first and second pads. Accordingly, the folded flexible circuit board with the image sensor can be directly inserted into an elongated tube to form an endoscope, such that the method of manufacturing the endoscope can be simplified and the flexible circuit board of the invention can be used for installing a micro image sensor with small dimensions.

DETAILED DESCRIPTION

Referring toFIGS.1to4,FIG.1is a perspective view illustrating an image capturing module10before being folded according to an embodiment of the invention,FIG.2is a perspective view illustrating parts of the image capturing module10shown inFIG.1from another viewing angle,FIG.3is a schematic view illustrating the image capturing module10shown inFIG.1, andFIG.4is a perspective view illustrating parts of the image capturing module10shown inFIG.1after being folded.

As shown inFIGS.1to3, an image capturing module10before being folded comprises a flexible circuit board100, an image sensor102, at least one light emitting unit104and at least one electrical component106. In this embodiment, the flexible circuit board100may be a flexible printed circuit board or other flexible circuit boards, the image sensor102may be a charge coupled device (CCD) image sensor, a complementary metal oxide semiconductor (CMOS) image sensor or other image sensors, the light emitting unit104may be a light emitting diode or other light emitting components, and the electrical component106may be a capacitor or other electrical components.

The flexible circuit board100comprises a plurality of first pads1000, a plurality of second pads1002and a plurality of third pads1004. In this embodiment, the flexible circuit board100may comprise four first pads1000, four second pads1002and four third pads1004, but the invention is not so limited. The number of the first pads1000, the second pads1002and the third pads1004may be determined according to practical applications.

The first pads1000may be disposed on a first surface S1of the flexible circuit board100and the second pads1002may be disposed on a second surface S2of the flexible circuit board100, wherein the first surface S1is opposite to the second surface S2. For further illustration, one of the first surface S1and the second surface S2may be au upper surface of the flexible circuit board100, and the other one of the first surface S1and the second surface S2may be a lower surface of the circuit board100.

In this embodiment, the first pads1000may be located at a first portion P1of the flexible circuit board100, the second pads1002may be located at a second portion P2of the flexible circuit board100, and the third pads1004may be located at a third portion P3of the flexible circuit board100, wherein the second portion P2is connected to the first portion P1and the third portion P3is connected to the second portion P2. In other words, the second portion P2is connected between the first portion P1and the third portion P3.

In this embodiment, the first pads1000are wider than the second pads1002. As shown inFIG.3, the second portion P2may be wider than the first portion P1and a width W of the second pads P2may be equal to a width difference Wd between the first portion P1and the second portion P2. Furthermore, the third portion P3may be wider than the second portion P2. The third pads1004are used for connecting a cable (not shown). Therefore, the wider the third portion P3is, the easier the cable can be welded with the third pads1004.

The image sensor102is disposed on the first surface S1of the flexible circuit board100, wherein a distance D1between the image sensor102and the first pads1000is identical to a distance D2between the image sensor102and the second pads1002, as shown inFIG.3. In other words, before the flexible circuit board100is folded, the image sensor102is located at a middle position between the first pads1000and the second pads1002. In this embodiment, the image sensor102may be connected to the first surface S1of the flexible circuit board100by surface mount technology (SMT), but the invention is not so limited.

In this embodiment, the image capturing module10may comprise two light emitting units104, but the invention is not so limited. The light emitting units104are disposed on the first surface S1of the flexible circuit board100, wherein a distance D3between the image sensor102and each of the light emitting units104is smaller than the distance D1or D2between the image sensor102and the first or second pads1000,1002, as shown inFIG.3. That is to say, the light emitting units104are closer to the image sensor102than the first or second pads1000,1002.

In this embodiment, the image capturing module10may comprise one electrical component106, but the invention is not so limited. The electrical component106may be disposed on the second surface S2of the flexible circuit board100with respect to the image sensor102. In other words, the image sensor102and the electrical component106are disposed on opposite surfaces of the flexible circuit board100.

In this embodiment, the flexible circuit board100may comprises a first folding segment1006, a second folding segment1008and a third folding segment1010, wherein the first folding segment1006is connected between the second folding segment1008and the third folding segment1010. The image sensor102and the electrical component106is located at opposite surfaces of the first folding segment1006, and the two light emitting units104are respectively located at the second folding segment1008and the third folding segment1010. It should be noted that, in another embodiment, the image capturing module10may comprise one light emitting unit104located at one of the second folding segment1008and the third folding segment1010. Accordingly, the image capturing module10may comprise at least one light emitting unit104located at at least one of the second folding segment1008and the third folding segment1010.

In this embodiment, the image sensor102, the light emitting units104and the electrical component106may be connected to the flexible circuit board100by surface mount technology (SMT) in one process. Then, as shown inFIG.4, the flexible circuit board100is folded to align and weld the first pads1000with the second pads1002, such that a light receiving surface1020of the image sensor102is perpendicular to surfaces of the first and second pads1000,1002. After the flexible circuit board100is folded, the first portion P1is superimposed on the second portion P2, the first folding segment1006is perpendicular to the second folding segment1008and the third folding segment1010, and the second folding segment1008and the third folding segment1010are parallel to each other. Furthermore, joints1012between the first folding segment1006, the second folding segment1008and the third folding segment1010have rounded recess structures1014. Accordingly, the first folding segment1006, the second folding segment1008and the third folding segment1010may be folded at the joints1012according to the rounded recess structures1014.

Referring toFIGS.5and6,FIG.5is a perspective view illustrating an endoscope1equipped with the image capturing module10shown inFIG.4andFIG.6is a perspective view illustrating the inside of the endoscope1shown inFIG.5.

As shown inFIG.5, an endoscope1comprises the aforesaid image capturing module10and a tube12, wherein the image capturing module10is disposed in the tube12. For further illustration, after the flexible circuit board100is folded and the first pads1000are welded with the second pads1002, the folded flexible circuit board100with the image sensor102can be directly inserted into the elongated tube12to form the endoscope1. As shown inFIG.6, the endoscope1may further comprise a light guide structure14disposed in the tube12. In this embodiment, the endoscope1may comprise two light guide structures14corresponding to the two light emitting units104, but the invention is not so limited. After the image capturing module10is inserted into the tube12, each of the light emitting units104is adjacent to the corresponding light guide structure14, such that the light guide structure14is able to guide light emitted by the light emitting unit104out of the tube12.

Referring toFIGS.7and8,FIG.7is a perspective view illustrating parts of the image capturing module10according to another embodiment of the invention andFIG.8is a perspective view illustrating the image capturing module10shown inFIG.7after being folded.

As shown inFIG.7, the image capturing module10may further comprise two support members108, wherein the two support members108are disposed on the second surface S2of the flexible circuit board100and respectively located at the second folding segment1008and the third folding segment1010. As shown inFIG.8, after the flexible circuit board100is folded, the two support members108abut against each other, such that the light emitting unit104can be kept at a fixed position to avoid deviation. Furthermore, in this embodiment, the image capturing module10may comprise two electrical components106, wherein the two electrical components106are disposed on the second surface S2of the flexible circuit board100with respect to the two light emitting units104. In other words, the two light emitting units104and the two electrical components106are disposed on opposite surfaces of the flexible circuit board100. In another embodiment, the electrical component106may also be disposed on the first surface S1of the flexible circuit board100with respect to the light emitting unit104and away from the image sensor102, so as to avoid that the electrical component106occludes the light emitted by the light emitting unit104projecting out the tube12. Therefore, the electrical component106may be disposed on at least one of the first surface S1and the second surface S2with respect to the light emitting unit104.

Referring toFIGS.9and10,FIG.9is a perspective view illustrating parts of the image capturing module10according to another embodiment of the invention andFIG.10is a perspective view illustrating the image capturing module10shown inFIG.9after being folded.

As shown inFIG.9, the flexible circuit board100of the image capturing module10may further comprise at least two fourth pads1016and at least two fifth pads1018for connecting the image sensor102. In this embodiment, the flexible circuit board100may comprise two fourth pads1016and two fifth pads1018, but the invention is not so limited. The two fifth pads1018are longer than the two fourth pads1016. Furthermore, the two fourth pads1016are located at the first folding segment1006and the two fifth pads1018extend from the first folding segment1006to the second folding segment1008.

In this embodiment, before the flexible circuit board100is folded, two contacts1022of the image sensor102may be connected to the two fourth pads1016first by surface mount technology (SMT). Then, the flexible circuit board100is folded to align the first pads1000with the second pads1002and make alight receiving surface1020of the image sensor102perpendicular to surfaces of the first and second pads1000,1002. Then, the other two contacts1024of the image sensor102are welded to the two fifth pads1018on the first surface S1of the flexible circuit board100while the first pads1000are welded with the second pads1002. Since the two contacts1024of the image sensor102are welded to the flexible circuit board100after the flexible circuit board100is folded, the second folding segment1008may be folded closer to the third folding segment1010, so as to further reduce the thickness of the folded flexible circuit board100.

Referring toFIG.11,FIG.11is a flowchart illustrating a method of manufacturing the image capturing module10according to an embodiment of the invention.

As shown inFIGS.1to11, first, step S10is performed to form a plurality of first pads1000and a plurality of second pads1002on a flexible circuit board100, wherein the first pads1000is disposed on a first surface S1of the flexible circuit board100, the second pads1002is disposed on a second surface S2of the flexible circuit board100, and the first surface S1is opposite to the second surface S2. Then, step S12is performed to dispose an image sensor102on the first surface S1, wherein a distance D1between the image sensor102and the first pads1000is identical to a distance D2between the image sensor102and the second pads1002. Then, step S14is performed to fold the flexible circuit board100to align the first pads1000with the second pads1002and make a light receiving surface1020of the image sensor102perpendicular to surfaces of the first and second pads1000,1002. Then, step S16is performed to weld the first pads1000with the second pads1002.

In this embodiment, the step S12may further comprise step of disposing at least one light emitting unit104on the first surface S1, wherein a distance D3between the image sensor102and the at least one light emitting unit104is smaller than a distance d1or D2between the image sensor102and the first or second pads1000,1002.

According to the embodiments shown inFIGS.1to4,7and8, the step S12may further comprise step of connecting the image sensor102to the first surface S1of the flexible circuit board100by surface mount technology (SMT).

According to the embodiment shown inFIGS.9and10, the step S12may further comprise step of connecting at least two contacts1022of the image sensor102to the first surface S1of the flexible circuit board100by surface mount technology (SMT), and the step S16may further comprise step of welding at least two contacts1024of the image sensor102to the first surface S1of the flexible circuit board100.

It should be noted that the detailed embodiments of the method of manufacturing the image capturing module10of the invention are mentioned in the above and those will not be depicted herein again.

As mentioned in the above, the invention disposes the image sensor on the flexible circuit board first and then folds the flexible circuit board to weld the first pads with the second pads thereon. At this time, the light receiving surface of the image sensor is perpendicular to surfaces of the first and second pads. Accordingly, the folded flexible circuit board with the image sensor can be directly inserted into an elongated tube to form an endoscope, such that the method of manufacturing the endoscope can be simplified and the flexible circuit board of the invention can be used for installing a micro image sensor with small dimensions.