CN216087097U - Environment-friendly copper post pad assembly suitable for COB display screen - Google Patents
Environment-friendly copper post pad assembly suitable for COB display screen Download PDFInfo
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- CN216087097U CN216087097U CN202121978252.3U CN202121978252U CN216087097U CN 216087097 U CN216087097 U CN 216087097U CN 202121978252 U CN202121978252 U CN 202121978252U CN 216087097 U CN216087097 U CN 216087097U
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Abstract
The utility model relates to an environment-friendly copper column bonding pad assembly suitable for a COB display screen, which comprises a copper column and a copper column bonding pad; the copper cylinder comprises a first cylinder, a second cylinder and a third cylinder which are coaxial from bottom to top, and the diameter of the second cylinder is larger than the diameter of the first cylinder and larger than the diameter of the third cylinder; the third cylinder is partially or completely embedded in the positioning hole of the copper column bonding pad; the ratio of the diameter of the copper column bonding pad to the diameter of the second cylinder is 0.9-1. The utility model has good tin climbing effect in the SMT process, no residual soldering flux around the copper column, no influence on the flatness after boxing and high surface consistency.
Description
Technical Field
The utility model relates to the technical field of COB display screen production, in particular to an environment-friendly copper column pad assembly suitable for a COB display screen.
Background
COB booth apart from LED display screen compares traditional SMD display screen, has seamless concatenation, and the display effect is good, advantages such as convenient transportation use, and in recent years obtains industry wide acceptance. The main fixing mode of the COB small-spacing LED display screen is that the copper columns are welded on the back face of the PCB panel by adopting an SMT (surface mount technology) process, and the copper columns are fixed on the box body back plate by using matched screws, so that the display panel is fixed.
The fixing mode of the small-spacing COB display screen still adopts the mode of welding copper columns and fixing screws, and fig. 1 and 2 are a copper column structure diagram and a copper column bonding pad diagram on a common PCB respectively; in fig. 2, a small positioning hole 21 is formed in the center of the copper pillar bonding pad 2 to position the copper pillar, the second cylinder portion 12 above the copper pillar has a stepped design, and a screw hole 111 is formed in the copper pillar for fixing a screw.
Along with the development of trade, the customer is constantly promoted to the environmental protection demand of product, most customers at home and abroad all require that SMT technology adopts lead-free tin cream to carry out the operation and just can accord with RHOS authentication standard, the process of lead-free tin cream has been introduced to the producer majority of present COB small-spacing LED display screen carries out SMT welding, but because the particularity of COB technology, need wash the remaining scaling powder around the copper post after the SMT welding, traditional method is that acetone washs the remaining scaling powder around back drive IC pin and the copper post, reuse ethanol washs PCB front.
The main defects of the prior art are as follows:
1. for the existing lead-free solder paste, the traditional cleaning process can clean partial flux residues, but cannot completely clean the flux residues, and the flatness after boxing is greatly influenced due to the flux residues around the copper columns in the boxing process.
2. If the water-based cleaning agent is used for cleaning the residual soldering flux, although the soldering flux on the back of the PCB can be cleaned, the cleaning agent residue is caused on the front of the PCB due to the poor volatility of the water-based cleaning agent, and the die bonding process and the display effect are influenced.
3. When the existing copper column welding pad is subjected to reflow soldering, due to the influence of high temperature, the difference of the thermal expansion coefficients of the welding pad and the bottom glass fiber board easily generates stress, so that the adhesion between the copper column welding pad on the back surface of the PCB and a copper column is reduced, and in addition, the height selection of the copper column is higher, the torsion resistance is reduced in the long-term use process, and the welding pad is easy to fall off.
4. The existing copper column can produce a large amount of copper scraps in the processing process of a copper column manufacturer, micron-sized copper cannot be cut and cleaned by a conventional cleaning means, and copper scraps attached to the copper column in the COB manufacturing process can fall on the front surface of a PCB to cause short circuit of partial chips.
Disclosure of Invention
The utility model aims to provide an environment-friendly copper column pad assembly suitable for a COB display screen.
In order to solve the technical problem, the environment-friendly copper column bonding pad assembly suitable for the COB display screen comprises a copper column and a copper column bonding pad; the copper cylinder comprises a first cylinder, a second cylinder and a third cylinder which are coaxial from bottom to top, and the diameter of the second cylinder is larger than the diameter of the first cylinder and larger than the diameter of the third cylinder; the third cylinder is partially or completely embedded in the positioning hole of the copper column bonding pad; it is characterized in that the diameter D of the copper column bonding pad and the diameter D of the second cylinder2The ratio of (A) to (B) is 0.9-1.
The height h and the outer diameter d of the first cylinder1The ratio is 0.5-1.
The upper step surface of the second cylinder is a plane, and the lower step surface is a chamfer surface.
The opening angles of the sawteeth around the second cylinder are all alpha, and the central interval angles between the teeth are all beta; the adjustable range of alpha is 45-85 degrees, and the adjustable range of beta is 20-60 degrees.
The second cylinder surrounding sawThe teeth being at an opening angle theta1And theta2Alternatively, the central spacing angles between the teeth are phi and theta1Is 45 to 85 DEG, theta245-85 degrees and phi is 20-60 degrees.
The sawteeth around the second cylinder are at two opening angles theta2And an opening angle theta1Alternately, the central spacing angles between the teeth are all phi; theta1Is 45 to 85 DEG, theta245-85 degrees and phi is 20-60 degrees.
The surface of the copper column is provided with a metal nickel protective layer.
The utility model has the beneficial effects that:
1. the diameter ratio of the copper column bonding pad to the second cylinder is 0.9-1, so that a good tin climbing effect can be achieved in the SMT process, no soldering flux is left around the copper column, flatness after boxing is not affected, and surface consistency is high.
2. Because the soldering flux around the copper cylinder is not remained, the procedure of cleaning after SMT can be cancelled, the cost is saved, the front surface of the PCB is not remained with a cleaning agent, and the display effect is better.
3. The first cylinder part of copper post reduces aspect ratio, can promote the torsion resistance ability after the copper post welding, and the PCB board after the vanning combines more firm with the box, has reduced the fault rate that the product used.
4. The edge of the second cylinder part of the copper column adopts a step-type sawtooth design mode, so that a better tin climbing effect in the welding process can be ensured, and a tin paste cavity in the welding process can be reduced.
5. The nickel metal protective layer is added on the surface of the copper column, so that the copper on the surface can be effectively wrapped, the chip short circuit caused by copper scraps in the generation process is avoided, and the abnormal proportion of the caterpillars is reduced.
Description of the drawings:
fig. 1 is a diagram of a copper pillar structure on a conventional PCB.
Fig. 2 is a top view of a copper pillar pad on a common PCB.
Fig. 3 is a schematic view of the copper pillar structure of the present invention.
Fig. 4a, 4b, 4c are top views of the second cylinder of three copper cylinders of the present invention.
In the figure: 11-a first cylinder, 111-a screw hole, 12-a second cylinder, 121-an upper step surface, 122-a lower step surface, 13-a third cylinder, 2-a copper column pad, and 21-a positioning hole.
Detailed Description
The present invention will be described in further detail with reference to the following drawings and examples, it being understood that the specific embodiments described herein are illustrative of the utility model only and are not limiting. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other suitable relationship. The specific meanings of the above terms in the present invention can be specifically understood in specific cases by those of ordinary skill in the art.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," or "beneath" a second feature includes the first feature being directly under or obliquely below the second feature, or simply means that the first feature is at a lesser elevation than the second feature.
In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used in the orientation or positional relationship shown in the drawings only for convenience of description and simplicity of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.
As shown in fig. 1 and 2, a conventional copper column for COB display screen includes a first cylinder 11, a second cylinder 12, and a third cylinder 13, which are integrally coaxial from bottom to top; the diameter of the second cylinder 12 > the diameter of the first cylinder 11 > the diameter of the third cylinder 13; a screw hole 111 is formed in the first cylinder 11 for fixing a screw; the periphery of the second cylinder 12 is designed to be stepped, the upper stepped surface 121 is a plane, and the lower stepped surface 122 is a chamfered surface; the top of the third cylinder 13 is chamfered, and the chamfer length is 0.2-0.5 mm; the height of the first cylinder is 3.9mm, the outer diameter is 3mm, the inner diameter of the thread is 2mm, and the length of the thread is 3.98 mm; the height of the second cylinder is 0.8mm, the diameter is 4.5mm, and the total height of the copper cylinder is 5.3 mm.
A small positioning hole 21 is formed in the center of the copper pillar bonding pad 2, the diameter of the copper pillar bonding pad 2 is 6mm, and the diameter of the positioning hole 21 is 1 mm; when in welding, the third cylinder 13 is partially or completely inserted into the positioning hole 21, and then the copper cylinder is welded on the copper cylinder welding pad 2 by using the lead-free tin paste.
As shown in fig. 3, the environment-friendly copper pillar pad assembly for COB display screens of the present invention includes a copper pillar and a copper pillar pad.
The copper cylinder include from the bottom up integrative coaxial first cylinder 11, second cylinder 12, third cylinder 13. The diameter of the second cylinder 12 > the diameter of the first cylinder 11 > the diameter of the third cylinder 13; a screw hole 111 is formed in the first cylinder 11 for fixing a screw; height h and outer diameter d of the first cylinder 111The ratio is 0.5-1, and on the premise of meeting the requirement of screw fixation, the smaller the ratio is, the stronger the torsion resistance is; the first cylinder 11 in this embodiment has a height h of 2.7mm and an outer diameter d13.5mm, the inner diameter of the screw hole 111 is 2mm, the length of the thread is 2.78mm, and the total height of the copper column is 4.1 mm; the periphery of the second cylinder 12 is designed to be stepped and zigzag, so that welding can be ensuredBetter tin climbing effect in the process of connection; the upper step surface 121 of the second cylinder 12 is a plane, and the lower step surface 122 is a chamfer surface, as shown in fig. 4a, the opening angles of the sawteeth around the second cylinder 12 may all be α, and the central spacing angles between the teeth are all β; alpha is 45-85 degrees, and beta is 20-60 degrees; as shown in FIG. 4b, the teeth around the second cylinder 12 may also have an opening angle θ1And theta2Alternatively, the central spacing angles between the teeth are phi and theta1Is 45 to 85 DEG, theta245-85 degrees and phi is 20-60 degrees; as shown in FIG. 4c, the teeth around the second cylinder 12 may also be at two opening angles θ2And an opening angle theta1Alternately, the central spacing angles between the teeth are all phi; in the specific embodiment, the diameter of the second cylinder is 4.5mm, and the second cylinder is designed in a step-like manner, θ1＝59°，θ252 °, 30 °; using opening angle theta1And theta2Alternating two opening angles theta2And an opening angle theta1And alternatively, the tin climbing effect in the welding process can be further improved, and the tin paste holes in the welding process are reduced.
A small positioning hole 21 is formed in the center of the copper column bonding pad 2; when in welding, the third cylinder 13 is partially or completely inserted into the positioning hole 21, and then the copper cylinder is welded on the copper cylinder welding pad 2 by using the lead-free tin paste. The diameter D of the copper column welding disc and the diameter D of the second cylinder2The ratio of (A) to (B) is 0.9-1, so that a better tin climbing effect in an SMT (surface mount technology) process can be ensured, and no fluxing agent is left around the copper column; specifically, the diameter of the bonding pad adopted in the embodiment is 4.5mm, and the diameter of the positioning hole 21 is 1 mm.
The surface of the copper column is plated with a metal nickel protective layer in an electroplating mode, so that the phenomenon that copper scraps fall off to the front surface of the PCB to cause short circuit of a chip can be avoided.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (7)
1. Be applicable to COB display screenThe environment-friendly copper column pad assembly comprises a copper column and a copper column pad; the copper cylinder comprises a first cylinder (11), a second cylinder (12) and a third cylinder (13) which are integrated and coaxial from bottom to top, wherein the diameter of the second cylinder (12) is larger than that of the first cylinder (11) and larger than that of the third cylinder (13); the third cylinder (13) is partially or completely embedded in the positioning hole (21) of the copper column bonding pad (2); it is characterized in that the diameter D of the copper column bonding pad and the diameter D of the second cylinder2The ratio of (A) to (B) is 0.9-1.
2. The COB display screen-adapted environment-friendly copper pillar pad assembly of claim 1, wherein the height h and the outer diameter d of the first cylinder (11)1The ratio is 0.5-1.
3. The COB display screen environment-friendly copper pillar pad assembly according to claim 1, wherein the upper step surface (121) of the second cylinder (12) is a flat surface, and the lower step surface (122) is a chamfered surface.
4. The COB display screen environment-friendly copper pillar pad assembly according to claim 1, 2 or 3, wherein the opening angles of the sawteeth around the second cylinder (12) are all alpha, and the central spacing angles between the sawteeth are all beta; the adjustable range of alpha is 45-85 degrees, and the adjustable range of beta is 20-60 degrees.
5. The COB display screen environment-friendly copper pillar pad assembly according to claim 1, 2 or 3, wherein the second cylinder (12) is sawed at an opening angle θ1And theta2Alternatively, the central spacing angles between the teeth are phi and theta1Is 45 to 85 DEG, theta245-85 degrees and phi is 20-60 degrees.
6. The COB display screen environment-friendly copper pillar pad assembly according to claim 1, 2 or 3, wherein the second cylinder (12) is sawed at two opening angles θ2And an opening angle theta1Alternatively, the central spacing angles between teethIs phi; theta1Is 45 to 85 DEG, theta245-85 degrees and phi is 20-60 degrees.
7. The COB display screen-suitable environment-friendly copper cylinder pad assembly of claim 1, wherein the copper cylinder surface has a metallic nickel protective layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121978252.3U CN216087097U (en) | 2021-08-23 | 2021-08-23 | Environment-friendly copper post pad assembly suitable for COB display screen |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121978252.3U CN216087097U (en) | 2021-08-23 | 2021-08-23 | Environment-friendly copper post pad assembly suitable for COB display screen |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216087097U true CN216087097U (en) | 2022-03-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121978252.3U Active CN216087097U (en) | 2021-08-23 | 2021-08-23 | Environment-friendly copper post pad assembly suitable for COB display screen |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216087097U (en) |
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2021
- 2021-08-23 CN CN202121978252.3U patent/CN216087097U/en active Active
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