Patent Application
20110186423
1. Technical Field
The present disclosure relates to electroplating apparatuses and, particularly, to an electroplating apparatus for electroplating flexible printed circuit boards (FPCBs).
2. Description of Related Art
In recent years, FPCBs have been widely used in portable electronic devices such as mobile phones, digital cameras, and personal digital assistants (PDAs). In these portable electronic products, some parts may move relative to a main body. In such applications, FPCBs can provide electrical connections between the main body and the movable parts.
A conventional electroplating apparatus includes an electroplating tank containing electroplating solution, a conveying unit, two anode plates, and an electric brush. The conveying unit and the anode plates are located in the electroplating tank. A substrate to be electroplated is moved along a straight line by the conveying unit. The anode plates are configured for supplying positive ions to the electroplating solution. The anode plates are located on two sides of the substrate, and are parallel with the movable direction of the substrate. In other words, the anode plates are perpendicular to the substrate.
The electric brush is configured to contact and supply electric current to the substrate. Because the substrate moves along a straight line, the electroplating tank must be very long. Accordingly, the electroplating apparatus occupies a lot of space. In addition, the arrangement of the anode plates usually results in non-uniform densities of positive ion across the substrate, which results in non-uniform thickness of the film applied to the substrate, thus a substrate with unsatisfactory quality is achieved.
Therefore, it is desirable to provide a new electroplating apparatus, which can overcome the above mentioned limitations.
Embodiments will now be described in detail below with reference to drawings.
Referring to
The pay out reel 11 is arranged adjacent to the first side 132 of the tank 13 and is configured for paying out the flexible substrate into the electroplating tank 13. The take up reel 12 is arranged adjacent to the second side 133 of the tank 13 and is configured for reeling in the electroplated flexible substrate from the first and second conveying rollers 140-146.
The electroplating tank 13 is circular in this embodiment, and includes a ring-shaped sidewall 130, and a bottom 131 perpendicular to the sidewall 130. In this embodiment, a mixing tube 134 is immersed in the electroplating solution, and is arranged on the bottom 131. The mixing tube 134 is configured for producing gas bubbles to promote mixture swirl in the electroplating solution.
The first conveying rollers 140, 142, 144, and 146 are immersed in the electroplating solution in the tank 13 and adjacent to the first side 132 of the tank 13. The first conveying rollers 140, 142, 144, and 146 are electrifiable to allow a current to flow through the flexible substrate, and are configured for revolving in a first rotating direction R1.
The second conveying rollers 141, 143, and 145 are immersed in the electroplating solution and adjacent to the second side 133 of the tank 13. The second conveying rollers 141, 143, and 145 are electrifiable to allow a current to flow through the flexible substrate, and are configured for revolving in a second rotating direction R2 opposite to the first rotating direction R1.
The first and second conveying rollers 140-146 are arranged in a staggered fashion and aligned with the respective anode plates 172-178. The first and second conveying rollers 140-146 are configured for cooperating to convey the flexible substrate from the pay out reel 11 to the take up reel 12 along a zigzag path 70 (see
In detail, the conveying rollers 140-146 are similar to each other and mechanically connected to a motor (not shown) by gears or belt (not shown), thereby making the conveying rollers 140-146 rotate together at the same velocity. The conveying rollers 140-146 are made of stainless steel, and the surfaces of the conveying rollers 140-146 are coated with titanium to prevent being electroplated. The first conveying rollers 140, 142, 144, 146 are both vertically aligned and parallel with each other as well as the bottom 131. The centers of the first conveying rollers 140, 142, 144, and 146 are arranged in a straight line. The distance between the centers of each two adjacent first conveying rollers of the first conveying rollers 140, 142, 144, and 146 is two times as long as the diameter of the first conveying roller 140.
The second conveying rollers 141, 143, and 145 are both vertically aligned and parallel with each other as well as the bottom 131. The centers of the second conveying rollers 141, 143, and 145 are arranged in a straight line. The distance between the centers of each two adjacent conveying rollers of second conveying rollers 141, 143, and 145 is two times as long as the diameter of the first conveying roller 140.
Along the depth direction of the tank 13, the distance between two centers of each two adjacent conveying rollers of the first and second conveying rollers 140-146 is equal to the diameter of the first conveying roller 140. For example, along the depth direction of the tank 13, the distance between two centers of the first conveying roller 140, and the second conveying roller 141 is equal to the diameter of the first conveying roller 140.
The motorized guide rollers, which are insulated and configured to guide the flexible substrate, are immersed in the electroplating solution. The guide rollers are similar to the conveying rollers, and the velocity of rotation of each guide roller is equal to the velocity of rotation of each conveying roller. The guide rollers includes at least one first guide roller 150, and at least one second guide roller 151. The at least one first guide roller 150 is located between the pay out reel 11 and the conveying rollers 140-146. The at least one first guide roller 150 is configured for guiding the flexible substrate from the pay out reel 11 to the conveying roller 140. The at least one second guide roller 151 is located between the take up reel 12 and the conveying rollers 140-146. The at least one second guide roller 15 is configured for guiding the electroplated flexible substrate from the conveying roller 146 to the take up reel 12. In the present embodiment, there is one first guide roller 150, and there are two second guide rollers 151. The first guide roller 150 is arranged at the first side 132 and near the first conveying roller 140, and a gap (not shown) is preserved between the first guide roller 150 and the first conveying roller 140. The second guide rollers 151, which is arranged at the second side 133 and near the second conveying roller 140, and the first conveying roller 140 are arranged at the same depth, and a gap (not shown) is preserved between the second guide rollers 151.
The motorized guide roller 16, is located at the second side 133, and is arranged between the second guide rollers 151 and the conveying rollers 140-146. In the present embodiment, the guide roller 16 and the conveying roller 146 are arranged at the same depth, and the guide roller 16 is nearer to the sidewall 130 than the second conveying rollers 141, 143, and 145.
The anode plates 172-178 are immersed in the electroplating solution, and are parallel with each other. The anode plates 172-178 are configured to electroplate the flexible substrate. In the present embodiment, the anode plates 172-178 are equidistantly spaced insoluble anodes, and are oriented parallel to a surface of the electroplating solution.
Each of the anode plates 172-178 includes a first end 170, and an opposite second end 171. In each two adjacent anode plates, the two first ends 170 of the two adjacent anode plates are adjacent to each other, and the two second ends 171 of the adjacent two anode plates are adjacent to each other. The first end 170 of one anode plate in the two adjacent anode plates is adjacent to one first conveying roller, and the second end 171 of the other anode plate in the two adjacent anode plates is adjacent to one second conveying roller, thereby making the flexible substrate move between the two adjacent anode plates when the flexible substrate is threaded around the two conveying rollers. In the present embodiment, the anode plates 172-178 are copper plates coated with titanium; the first ends 170 are located adjacent to the first side 132 of the tank 13 as the pay out reel 11, and the second ends 171 are located adjacent to the second side 133 of the tank 13 as the take up reel 12. The distance between each two adjacent anode plates is equal to the diameter of the first conveying roller 140, and the center of conveying roller and the corresponding anode plate is in a straight line.
In detail, the first end 170 of the anode plate 172 is adjacent to the first conveying roller 140, and the first end 170 of the anode plate 172 and the center of the first conveying roller 140 are in a straight line. The second end 171 of the anode plate 172 aligns with the edge of the second conveying roller 141. The second end 171 of the anode plate 173 is adjacent to the second conveying roller 141, and the second end 171 of the anode plate 173 and the center of the second conveying roller 141 are in a straight line. The second end 170 of the anode plate 173 aligns with the first conveying roller 140. The arrangements of the anode plate 174, the anode plate 176, and the anode plate 178 are similar to that of the anode plate 172, expect that the second end 171 of the anode plate 178 is adjacent to the guide roller 16, and the second end 171 of the anode plate 178 and the centers of the guide roller 16 are in a straight line. The arrangements of the anode plate 175, the anode plate 177 are similar to that of the anode plate 173.
The insulated clapboards 180-187 are immersed in the electroplating solution, and are connected with the respective anode plates for separating the anode plates 172-178 from the corresponding first and second conveying rollers 140-146.
In detail, the insulated clapboard 180 is located between the first conveying roller 140 and the first end 170 of the anode plate 172, and is connected with the first end 170 of the anode plate 172. The insulated clapboard 181 is located between the conveying roller 141 and the second end 171 of the anode plate 173, and is connected with the second end 171 of the anode plate 173. The insulated clapboard 182 is located between the conveying roller 142 and the first end 170 of the anode plate 174, and is connected with the first end 170 of the anode plate 174. The insulated clapboard 183 is located between the conveying roller 143 and the second end 171 of the anode plate 175, and is connected with the second end 171 of the anode plate 175. The insulated clapboard 184 is located between the conveying roller 144 and the first end 170 of the anode plate 176, is connected with the first end 170 of the anode plate 176. The insulated clapboard 185 is located between the conveying roller 145 and the second end 171 of the anode plate 177, and is connected with the second end 171 of the anode plate 177. The insulated clapboard 186 is located between the conveying roller 146 and the first end 170 of the anode plate 178, and is connected with the first end 170 of the anode plate 178. The insulated clapboard 187 is located between the guide roller 16 and the second end 171 of the anode plate 178, and is connected with the second end 171 of the anode plate 178.
In this embodiment, each of the insulated clapboards 180-187 is perpendicular to the corresponding anode plates 172-178, and the length of each insulated clapboard along a direction perpendicular to the corresponding anode plate is longer than the thickness of the corresponding anode plate. In the present embodiment, the insulated clapboards 180-187 are square plates, and are made of acrylonitrile butadiene styrene. In other embodiment, the insulated clapboards 180-187 may be made of polyvinylchloride.
In alternative embodiments, the number of the conveying rollers is not limited to seven; the number of the anode plates is not limited to seven; the number of the insulated clapboards is not limited to eight. In further alternative embodiments, the anode plates 172-178 may be perpendicular to the bottom 131. In other further alternative embodiments, the anode plates 172-178 may be inclined relative to the central axis of the tank 13.
The positive ion supply bath 19 is configured for supplying a positive ion solution to the tank 13. The positive ion supply bath 19 includes a delivery pipe 190. In the present embodiment, the positive ion solution is sulfate for dissolving copper sulfate to obtain positive copper ions.
The automatic positive ion supply system 20 includes a positive ion concentration detector 21, a controlling device 22, and an infusion pump 23. The concentration detector 21 is immersed in the electroplating solution for detecting the positive ion concentration in the electroplating solution in the tank 13. The infusion pump 23 is connected to the positive ion supply bath 19 by delivery pipe 190. The controlling device 22 is configured for receiving detected positive ion concentration values from the concentration detector 21, and controlling the infusion pump 23 to pump the solution in the positive ion supply bath 19 into the tank 13 when the detected positive ion concentration value is lower than a predetermined value.
Referring also to
First of all, a flexible substrate 100 is provided. The flexible substrate 100 can be a soft substrate with the two opposite surfaces coated with copper layers formed by chemical deposition. Most of the flexible substrate 100 is wound onto the pay out reel 11, and some of the flexible substrate 100 is set between the conveying rollers, and the guide rollers. In detail, one end of the flexible substrate 100 is passed through the gap between the first guide roller 150 and the conveying roller 140, and then is threaded around the conveying roller 141, the conveying roller 142, the conveying roller 143, the conveying roller 144, the conveying roller 145, the conveying roller 146, and the guide roller 16 in that order, and finally passes through the gap between the second guide rollers 151 and to be wound onto the take up reel 12.
Then, an electric source (not shown) of the electroplating apparatus 10 is turned on, and the flexible substrate 100 is reeled through the tank 13 and electroplated.
The electroplating process for a section of the flexible substrate 100, which is about to enter into the tank 13, will be described below.
As can be clearly seen in
In the electroplating process, because each anode plate is parallel the surface of the flexible substrate 100, and distances between different points at the surface of the flexible substrate 100 and the corresponding anode plates are equal to each other, the positive ion densities at the different points are equal to each other on the surface of the flexible substrate 100, thereby making the electroplating layer formed on the surface of the flexible substrate 100 have a satisfactory uniform thickness. In addition, the conveying rollers in the electroplating apparatus 10 not only supply current to the flexible substrate 100, but also move the flexible substrate 100, and convert the movable direction of the flexible substrate 100, thereby making the flexible substrate 100 move back and forth regularly. Accordingly, the length of the tank 13 can thus be reduced, and the electroplating efficiency can be improved.
While certain embodiments have been described and exemplified above, various other embodiments will be apparent to those skilled in the art from the foregoing disclosure. The disclosure is not limited to the particular embodiments described and exemplified but is capable of considerable variation and modification without departure from the scope and spirit of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201010300909.0 | Jan 2010 | CN | national |
