JPS6144854Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printed circuit board manufacturing process, and relates to a printing screen that is effective when applied to print a circuit pattern on the printed circuit board.

Conventionally, regardless of whether the printed circuit board to be processed is a through-hole board or a non-through-hole board, for example, when forming a conductor circuit pattern on a copper-clad laminate, or after forming the pattern, forming a solder resist pattern. For this purpose, the screen printing method includes one step of pattern generation in which a resist agent is applied.

In applying the resist agent in this process, a mesh screen of about 320 mesh made of stainless steel or the like is brought into close contact with the processed printed circuit board, and the resist agent is extruded through the mesh with a squeegee to perform application printing.
However, in such a method, printing misalignment occurs due to the elongation of the screen due to the pressure of the coating squeegee and the expansion and contraction of the processed substrate during manufacturing. For example, when printing solder resist to prevent solder bridging during soldering and to pattern an insulating film, if there is a printing misalignment, the resist will be deposited on unnecessary surfaces such as lands on which components are mounted, and between other wiring conductors. Resist does not adhere to parts that require insulation,
This will interfere with circuit board formation. In recent years, with the demand for finer wiring patterns on substrates, the problem caused by the printing misalignment has become a situation that cannot be taken lightly.

The present invention has been made to solve the above-mentioned disadvantages, and as a means of solving the problem, a printing screen is provided that has a frame that allows the screen tension to be freely changed around the screen during printing.

That is, the conventional structure in which the screen frame is fixed has been changed to a screen frame that can cope with the expansion of the screen during use.

According to the present invention, in a printing screen consisting of a screen member and a frame supporting the screen member, each side frame of the frame has an inner member mechanically fixed to the inner member and a flexible member attached to the inner member. and a space surrounded by the inner member, the outer member, and the flexible member, and a hole for introducing gas into the space is arranged in the frame. There is provided a printing screen in which the screen member is fixed to an outer member of the frame.

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing the main structure of the frame taken along the line A-A' in FIG.

In FIG. 1, 1 is a screen having a fine mesh made of silk, tetoron, etc., and 2, 3, 4, and 5 are frames forming the main parts of the device to which the screen 1 is fixed at the periphery. The body consists of a frame member made of aluminum or an equivalent metal on the inside and outside, and a flexible member made of bellows-shaped phosphor bronze or vinyl chloride on the upper and lower sides, and the inside is hollow. (See the cross-sectional view in Figure 2). Reference numeral 6 denotes an air supply hole for pressurizing air into the cavity of each frame on each side. With such a configuration, by pressurizing air into the frame, a flexible screen tension can be applied to the screen surface in either the X direction or the Y direction in the drawing.

The operation of the screen frame of the present invention using air pressure will be explained with reference to FIG. In FIG. 2, the screen 1 is adhered to the outer frame member 8 with adhesive tape, and a backing plate 10 is attached to the surface of the screen 1, and the screen 1 is fixed with an appropriate tension. In addition, the inner frame member 7 is a fixing frame portion similar to the conventional one for mechanically fixing the side frames to each other, and the screen 1 is only lightly in contact with its lower end 11. Therefore, if air is gradually forced in from the air supply pipe 6, pressure will be generated inside the cavity as shown by the dotted line in the figure, and since the inner frame member is fixed, the frame will be expanded outward by the flexible member and at the same time a screen tension will be applied. Ru. Incidentally, to show the amount of printing misalignment correction or pattern matching correction by the tension for reference, in pattern printing where the screen frame dimensions of the embodiment diagram in Fig. 1 are, for example, 500 x 500 mm, The fine dimensions of about 20 to 50 microns (unit: 10 ^-3 mm) can also be adjusted in the axial direction.

As described above, by using the printing screen frame of the present invention as described above, it becomes easy to form fine wiring patterns that are required in recent years. Furthermore, it is possible to deal with the problem by applying conventional techniques as is. From this point of view, the present invention has great practical value.

In the embodiment, the air injection hole is provided in the flexible member, but it goes without saying that it may be provided in the inner member or the outer member.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a printing screen according to the present invention, and FIG. 2 is a sectional view showing the frame structure of FIG. 1. In the figure, 1 is a screen, 2, 3, 4, and 5 are frame bodies, 6 is an air pressure hole, 7 and 8 are inner and outer frame members, 9 is a flexible member, and 10 is a backing plate that fixes the screen 1. It is.

Claims (1)

[Scope of utility model registration request] In a printing screen comprising a screen member and a frame supporting the screen member, each side frame of the frame has an inner member mechanically fixed to the outer member and an outer member supported by a flexible member to the inner member. The screen member has a space surrounded by the inner member, the outer member and the flexible member, a hole for introducing gas into the space is arranged in the frame body, and the screen member has a space surrounded by the inner member, the outer member and the flexible member. A printing screen, characterized in that it is fixed to an outer member of the frame.