CN101141855A

CN101141855A - Halftone

Info

Publication number: CN101141855A
Application number: CNA200710181571XA
Authority: CN
Inventors: 种国卿
Original assignee: Fujian Star Net Communication Co Ltd
Current assignee: Fujian Star Net Communication Co Ltd
Priority date: 2007-10-23
Filing date: 2007-10-23
Publication date: 2008-03-12

Abstract

The present invention discloses a web plate, which comprises at least an opening location of a corresponding bonding pad, and at least one opening location comprises at least two openings in the opening location. At least two openings are arranged into at least two lines, and at least two lines of different opening quantities exist in the at least two rows, or the at least two openings are arranged into at least two rows and two lines. The shape of the at least two openings is same, or at least two different openings shapes exist in the at least two openings. The opening can be an oval and a polygon, etc. The adoption of the web plate provided by the present invention can ensure that the whole bonding pads are even when the paste is printed, an amount of a soldering tin is coated, the problems of the stack up of the paste in the middle part of the bonding pad, and the false welding, the sealing off and the inaesthetic welding are avoided. Therefore, the welding reliability with a large-area bonding pad component is guaranteed.

Description

Web plate

Technical field

The present invention relates to the electric and electronic technical field, relate in particular to a kind of web plate.

Background technology

In the electric and electronic technical field, electronic product is tending towards pursuing miniaturization and high density, requirement to its Performance And Reliability improves, require product lot quantityization simultaneously, the production automation and lower production cost, this impels most electronic product when assembling, adopts surface mounting technology (SMT, Surface MountedTechnology).SMT relies on intrinsic advantage to become the packaging technology of present main flow.

The production of sticking-element need be finished at special SMT production line, and the main flow process of SMT has: prepare print solder paste, reflow soldering and check before the welding.Wherein, preparation mainly comprises before the welding: the preparation of material, scolder, welding drawing, the oven dry of printed board etc.; The technological process of print solder paste comprises: the installation of web plate, regulate parameter, and printed solder paste is checked on the quality, and finishes and the cleaning web plate.Briefly, the process of print solder paste is exactly that metal form with web plate covers on the printed circuit board, the corresponding bonding pad position is accurately aimed at, required printing one deck solder(ing) paste, the pad of printed board is coated with applies an amount of scolding tin according to the operation of Surface Mount equipment; The process of reflow soldering is: the pin of components and parts is placed on the pad, and heating with reflow ovens makes the solder(ing) paste fusing, thereby components and parts and printed board are firmly linked together; Check is that the printed circuit board that butt welding connects carries out the detection of welding quality.

The web plate structure of using in the process of print solder paste as shown in Figure 1, the housing of web plate is generally the cast aluminium framework, mid portion is a metal form, there is perforate the position of corresponding printed board pad above the metal form, perforate is corresponding with the position of pad.Web plate covers effect in the printed board shown in Fig. 2 a, and the pad 23 that the perforate of the metal form 21 of web plate is aimed on the printed circuit board 22 is placed, and size is generally big slightly than pad.The situation of pad 23 after Fig. 2 b, Fig. 2 c represent print solder paste 24 backs respectively and take away web plate.

To all pads, the web plate perforate is all according to producing extensively slightly than pad in the prior art.This way can have problems for the bigger pad of area.Because there is certain force of strain on liquid scolding tin surface, can cause the large tracts of land pad when print solder paste, the scolding tin that applies on the pad is inhomogeneous, and shown in Fig. 3 a, Fig. 3 b, tin cream 24 relatively concentrates on the middle part of pad 23, cause the middle part tin cream thicker, the edge tin cream is thin even do not have tin cream, thereby middle thicker part will be with components and parts jack-up in reflow soldering, cause other pin failure welding and cause rosin joint, and the inhomogeneous influence of height is attractive in appearance; In addition, this large tracts of land pad usually is used for triode, in the high power devices such as power source conversion, these devices can produce many heats when work, cause the temperature of solder joint higher, such temperature can make tin cream expand, and weld point temperature is reduced to room temperature again after shutdown, and pin and tin cream will shrink, because the pad mid portion is thick, not yielding, stress can focus on thin marginal portion, and the edge is squeezed during high temperature, be stretched again during low temperature, along with the switching on and shutting down alternate, push and be stretching in again and again and carry out, through after a while, weld will cracking occur because of metal fatigue, causes the components and parts pin problems such as sealing-off to occur.

Summary of the invention

The technical problem that the embodiment of the invention will solve is to provide a kind of web plate, to guarantee to have the soldering reliability of large tracts of land pad components and parts.

The web plate that the embodiment of the invention proposes comprises the perforate position of at least one corresponding pad having at least a perforate position to comprise at least two perforates in the described perforate position.

Described at least two perforates are arranged at least two row, and the perforate number difference that has at least two row at least in described two row.

Described at least two perforates are arranged at least two row two row.

Described at least two hole shapes are identical.

Described perforate is oval.

Described perforate is a polygon.

Described perforate is a triangle.

Described perforate is square.

In described two perforates, there are at least two hole shape differences at least.

The web plate that the embodiment of the invention proposes, for the large tracts of land pad, the perforate position of web plate correspondence is designed to comprise the form of at least two perforates, thereby the components and parts of having avoided having the large tracts of land pad easily cause rosin joint, sealing-off and inaesthetic problem, have guaranteed to have the soldering reliability of large tracts of land pad components and parts.

Description of drawings

Fig. 1 is the structural representation of web plate in the prior art;

Fig. 2 a is that web plate covers situation schematic diagram in the printed board in the prior art;

Fig. 2 b is the situation schematic diagram after print solder paste under the situation shown in Fig. 2 a;

Fig. 2 c is for taking away the situation schematic diagram behind the web plate under the situation shown in Fig. 2 b;

Fig. 3 a is the vertical view after the print solder paste on the large bonding pad in the prior art;

Fig. 3 b is the front view after the print solder paste on the large bonding pad in the prior art;

First kind of web plate open-celled structure schematic diagram that Fig. 4 proposes for the embodiment of the invention;

Fig. 5 a is that the web plate of embodiment of the invention proposition covers the situation schematic diagram in the printed board;

Fig. 5 b is second kind of web plate open-celled structure schematic diagram that the embodiment of the invention proposes;

Fig. 6 a is the third web plate open-celled structure schematic diagram that the embodiment of the invention proposes;

Fig. 6 b is the 4th kind of web plate open-celled structure schematic diagram that the embodiment of the invention proposes;

Fig. 6 c is the 5th kind of web plate open-celled structure schematic diagram that the embodiment of the invention proposes;

Fig. 6 d is the 6th kind of web plate open-celled structure schematic diagram that the embodiment of the invention proposes;

Fig. 6 e is the 7th kind of web plate open-celled structure schematic diagram that the embodiment of the invention proposes.

Embodiment

The web plate that the embodiment of the invention proposes comprises the perforate position of at least one corresponding pad, comprises at least two perforates in described at least one perforate position.

Below in conjunction with Figure of description the specific embodiment of the present invention is described.

For the large tracts of land pad, the perforate position of its web plate correspondence should be bigger slightly than bonding pad area, the web plate that the embodiment of the invention proposes is not designed to a perforate with described perforate position, but with a plurality of perforates of design in the described perforate position, as shown in Figure 4, outmost frame table shows the size of pad among the figure, and the pane of the inside is perforate corresponding on the web plate.Fig. 5 a has provided this web plate metal form 21 has been covered situation on the printed circuit board 22, can see, be actually large tracts of land pad 23 has been divided into some little pads, and these little pads distribute relatively even, guarantee that all even, an amount of being coated with of whole pad applies scolding tin when print solder paste.Thereby can avoid tin cream 24 to pile up, cause rosin joint, sealing-off and weld inaesthetic problem at the middle part of pad 23.

Certainly, a perforate position of web plate also can be shown in Fig. 5 b, and promptly all comprise at least one perforate position, have at least a perforate position to comprise the steel plate structure of at least two perforates in the described perforate position, all belong within the invention which is intended to be protected.

For the large tracts of land pad, the perforate of its web plate can be adopted other shapes, as circular (seeing shown in Fig. 6 a), triangle (seeing shown in Fig. 6 b), polygon (seeing shown in Fig. 6 c).Certainly, the perforate of web plate also can be adopted the perforate of other arbitrary shapes, in a perforate position that comprises at least two perforates, has the web plate structure of other arbitrary shape perforates, also should belong within the invention which is intended to be protected.

It should be noted that the web plate structure that the embodiment of the invention proposes, it is capable to comprise M in the perforate position, the perforate of N row, and wherein M can be not equal to N (shown in Fig. 6 b), and M also can equal N (shown in Fig. 6 c).All comprise at least two perforates in a perforate position, described at least two perforates are arranged in the web plate structure of at least two row two row, all belong within the invention which is intended to be protected.

In addition, the web plate structure that the embodiment of the invention proposes also can comprise the capable perforate of M in the perforate position, wherein exists the perforate number of at least two row not wait, shown in Fig. 6 d.Also be in the web plate structure that proposes of the present invention, at least two perforates that are also contained in the perforate position are arranged at least two row, and have the perforate number differences of at least two row at least in described two row.All web plates that satisfy said structure all belong within the invention which is intended to be protected.

In addition, the web plate structure that the embodiment of the invention proposes, each hole shape in perforate position also can be different, shown in Fig. 6 e.Have and exist at least two different web plate structures of hole shape all to belong to the scope of protection of present invention at least in two perforates in a perforate position.Hole shape can be circle, and ellipse is square, triangle, other polygons, and other irregular shapes.

The web plate that adopts the embodiment of the invention to propose breaks the whole up into parts large bonding pad, and the tension force influence of scolding tin is reduced greatly, makes on the whole pad tin cream coating more even, thereby can be because middle tin cream is thicker with components and parts jack-up.

The web plate that adopts the embodiment of the invention to propose, because scolding tin is more even on the pad, the various piece of pad is subjected to temperature stress to influence the comparison equilibrium, can avoid the problem of sealing-off occurring owing to expand with heat and contract with cold.

The web plate that adopts the embodiment of the invention to propose, can avoid the welding height of components and parts inhomogeneous, the welding effect better appearance, whole pad is connected with the pin of components and parts by a plurality of solder joints, strengthened connectedness, simultaneously need on whole large bonding pad, not brush tin cream, can energy-saving and emission-reduction, save scolding tin and energy.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims

1. web plate comprises the perforate position of at least one corresponding pad it is characterized in that having at least a perforate position to comprise at least two perforates in the described perforate position.

2. web plate as claimed in claim 1 is characterized in that, described at least two perforates are arranged at least two row, and

The perforate number difference that in described two row, has at least two row at least.

3. web plate as claimed in claim 1 is characterized in that, described at least two perforates are arranged at least two row two row.

4. as claim 1,2 or 3 described web plates, it is characterized in that described at least two hole shapes are identical.

5. web plate as claimed in claim 4 is characterized in that, described perforate is oval.

6. web plate as claimed in claim 4 is characterized in that, described perforate is a polygon.

7. web plate as claimed in claim 6 is characterized in that, described perforate is a triangle.

8. web plate as claimed in claim 6 is characterized in that, described perforate is square.

9. as claim 1,2 or 3 described web plates, it is characterized in that, in described two perforates, have at least two hole shape differences at least.