Certain embodiments of a method for manufacturing a cover lay of a printed circuit board according to the invention will be described below in more detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, those components are rendered the same reference numeral that are the same or are in correspondence regardless of the figure number, and redundant explanations are omitted.
First, a board 10 on which a circuit pattern 20 is formed may be prepared (S1). The circuit pattern 20 may be formed on the board 10, where the circuit pattern 20 may serve to deliver electrical signals. The cover lay may be formed to protect this circuit pattern 20.
Next, a protecting ink 40 may be jetted selectively on the board 10 by an inkjet head 30 (S2). Before describing this operation in further detail, the inkjet head 30 used in this embodiment will be described below referring to
The reservoir 31 may contain the protecting ink 40, and provide the protecting ink 40 to the chamber 33 through the restrictor 32.
The restrictor 32 may serve as a channel that connects the chamber 33 with the reservoir 31, and provide the protecting ink 40 to the chamber 33 from the reservoir 31. The restrictor 32 may be formed with a cross-sectional area smaller than that of the reservoir 31. Also, the restrictor 32 may control the amount of ink provided from the reservoir 31 to the chamber 33 when the vibration plate 35 is made to vibrate by the piezoelectric element 36.
The chamber 33 may be connected with the reservoir 31 by the restrictor 32. Moreover, the side of the pressure chamber 33 that is not connected with the restrictor 32 may be connected with the nozzle 34. Therefore, the chamber 33 may receive the protecting ink 40 from the reservoir 31 and provide the protecting ink 40 to the nozzle 34, whereby printing may take place.
One side of the chamber 33 may be covered by the vibration plate 35, and the piezoelectric element 36 may be joined on the upper side of the vibration plate 35 in correspondence to the location of the chamber 33.
The piezoelectric element 36 may be joined on the upper side of the vibration plate 35 in correspondence to the location of the chamber 33, and may generate vibrations. The piezoelectric element 36 may supply a driving pressure to the chamber 33 by receiving electrical power from the power supply 37 and generating the vibration.
The nozzle 34 may be connected with the chamber 33, and may receive the protecting ink 40 from the chamber 33 and jet the protecting ink 40. When a vibration generated by the piezoelectric element 36 is provided to the chamber 33 through the vibration plate 35, a pressure may be supplied to the chamber 33, at which the nozzle 34 may jet the protecting ink 40 by the pressure.
While the inkjet head 30 of a piezoelectric type having the structure described above is illustrated for describing this embodiment with reference to
The protecting ink 40 may be jetted on the board 10 on which the circuit pattern 20 is formed, and form a cover lay after hardening. The protecting ink 40 may be made of a polyimide, epoxy resin, polyacrylate or polyurethane, or combinations thereof. In addition, it is apparent that various other kinds of material suitable for the inkjet head 30 may be applied as necessary. In this embodiment, a polyimide is presented as an example of the protecting ink 40.
A polyimide is a polymer having an imide group in its main chain. Polyimides have the mechanical features of high compressive strength, high impact resisting strength and high tensile strength, and electrical features of low permittivity and high electric resistance. Also, polyimides have high thermal resistance, high resistance to oxidation at high temperatures, high chemical resistance and low rates of thermal expansion.
The protecting ink 40 may be formed by dispersing a polymer such as a polyimide in a solvent, or dispersing monomers of a polymer in a solvent. The protecting ink 40 may itself be made of monomers.
A protecting ink 40 formed by dispersing monomers or polymers in a solvent may have low viscosity and thus may be suitable for jetting. This has the merit of simplifying the manufacturing process, because evaporation and polymerization of the solvent may occur after the jetting. In addition, a cover lay formed from a protecting ink 40 made of monomers may be over 10 μm and may provide high adhesion and high strength.
As described above, the form of the protecting ink 40 may be changed according to the requirements of the designer or user.
Before jetting the protecting ink 40 by inkjet printing, the protecting ink 40 may be filtered to eliminate particles of excessively large sizes that may block the nozzle 34 of the inkjet head 30.
Also, cleaning or surface treatment may be performed on the board 10 to enhance adhesion and control the contact angle. The washing may be performed by any of a variety of methods, such as by removing pollutants with an organic solvent or an alkali cleaning solution, by etching with acidic materials such as a chromic acid, sulphuric acid or hydrochloric acid, by shot blasting, by anodizing, or by eliminating a pollutant with ions or plasma. The cleaning may also be performed by other commonly known methods for eliminating pollutants.
To enhance adhesion between the board 10 and the protecting ink 40, an adhesion improver may be applied on the board 10 before jetting the protecting ink 40.
Then, the filtered protecting ink may be jetted on the board 10 by inkjet printing.
Next, the protecting ink 40 may be hardened (S3). This is because the protecting ink 40 jetted on the board 10 for forming a cover lay may be a liquid or a paste and thus may need to be hardened in order to serve as a cover lay protecting the circuit pattern 20.
Supplying heat or UV (ultraviolet) rays may be presented as a method for hardening the protecting ink 40. Specifically, if the protecting ink 40 includes a polymer dispersed in a solvent, the protecting ink 40 may be hardened by evaporating the solvent using a thermal treatment at 200° C. for 30 minutes. Also, if the protecting ink 40 includes monomers dispersed in a solvent or monomers themselves, the protecting ink 40 may be hardened by polymerizing the monomers by supplying heat or UV rays to the protecting ink 40.
According to the present invention comprised as above mentioned, a cover lay of a complicated shape may be formed easily with high accuracy and high productivity, by jetting a polymer ink by inkjet printing to form the cover lay for a flexible circuit board.
While the above description has pointed out novel features of the invention as applied to various embodiments, the skilled person will understand that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made without departing from the scope of the invention. Therefore, the scope of the invention is defined by the appended claims rather than by the foregoing description. All variations coming within the meaning and range of equivalency of the claims are embraced within their scope.
Number | Date | Country | Kind |
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10-2006-0097436 | Oct 2006 | KR | national |