Gold thread connecting structure in LED module and LED module

Abstract

The utility model relates to the technical field of LED packaging, in particular to a gold thread connecting structure in an LED module and the LED module, which comprises a fixed end support, an LED wafer is arranged on the fixed end support, two ends of a gold thread are electrically connected with the LED wafer and a welding end support respectively, at least part of the area section of the gold thread is parallel to and close to the plane where the welding end support is located, and the welding end support is arranged on the fixed end support. At least part of the area section of the gold thread is parallel to and close to the plane where the welding end support is located, when the size of the packaging colloid is changed due to temperature change, the pulling stress borne by the gold thread is small, compared with a traditional structure, the layout reduces stress concentration caused by thermal expansion and cold contraction of the packaging colloid, and the packaging effect is improved. The risk that welding spots or gold wires are broken due to stress concentration is greatly reduced, and the reliability of the LED module in a temperature change environment is remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of LED packaging technology, and in particular to a gold wire connection structure in an LED module and the LED module itself. Background Technology

[0002] With the widespread application of LED lighting, displays, and other technologies, increasingly higher demands are being placed on the performance and reliability of LED modules. Small-size LED modules, with their advantages of small size, high integration, and high luminous efficiency, are widely used in various LED products. In the process of constructing LED modules from small-size LED chips, gold wire bonding is a key technology for achieving electrical connections between the chip and external circuits; its connection quality and reliability directly affect the overall performance and lifespan of the LED module.

[0003] In practical applications, LED modules often face prolonged temperature variations. When the ambient temperature fluctuates, the volume of the encapsulating colloid encapsulating the small LED chip changes due to thermal expansion and contraction. Silicone, with its excellent insulation, flexibility, and optical properties, is one of the commonly used materials in LED encapsulation. However, silicone has a relatively large coefficient of thermal expansion, making the volume change of the silicone encapsulating colloid more significant during temperature changes. When the encapsulating colloid undergoes volume changes, it generates tensile stress on the closely connected gold wires. Studies have shown that the larger the gold wire span, the greater the tensile stress the gold wires bear under the same thermal expansion and contraction conditions, and the higher the risk of breakage of the solder joint or gold wire due to stress concentration. Once the solder joint breaks, the electrical connection between the LED chip and the external circuitry is interrupted, thus preventing the LED module from functioning properly.

[0004] Currently, in LED module manufacturing, traditional gold wire bonding processes generally employ a high curvature. When the ambient temperature of the LED chip increases, the high-curvature gold wire will undergo significant deformation due to heat. According to thermal stress theory, this significant deformation further increases the internal stress of the gold wire. During repeated temperature changes, the gold wire is subjected to the combined effects of thermal expansion and contraction and the tensile stress of the encapsulating colloid, significantly exacerbating the risk of breakage due to stress fatigue. Therefore, existing LED chip gold wire connection structures and processes have obvious defects, urgently requiring a new gold wire connection structure and related technologies to effectively solve the reliability problem of gold wire connections for small-sized LED chips under temperature variation environments. Utility Model Content

[0005] The purpose of this utility model is to provide a gold wire connection structure and an LED module in an LED module, which aims to solve the problem of gold wire breakage due to stress fatigue under the dual effects of thermal expansion and contraction and tensile stress of encapsulant in the above-mentioned technical problem, and to ensure the service life of the LED module.

[0006] The technical problem solved by this utility model is addressed by the following technical solution: a gold wire connection structure in an LED module, comprising:

[0007] Fixed end bracket;

[0008] LED chips are mounted on the fixed end bracket;

[0009] Welding end support;

[0010] The gold wire is electrically connected at both ends to the LED chip and the welding end bracket, respectively. The fixing surface of the LED chip and the fixing surface of one end of the gold wire on the welding end bracket are coplanar.

[0011] In this configuration, at least a portion of the gold wire is arranged parallel to and adjacent to the surface where the welding end support is located.

[0012] This utility model also has the following technical features:

[0013] In one embodiment of this utility model, a horizontal segment extends from the gold wire, and the horizontal segment is parallel to the plane where the welding end bracket is located.

[0014] In one embodiment of this utility model, the ratio of the length of the horizontal segment to the span distance between the two welding ends of the gold wire is greater than or equal to 1 / 4.

[0015] In one embodiment of this utility model, the distance between the horizontal segment and the surface where the welding end bracket is located is less than 0.5 mm.

[0016] In one embodiment of this utility model, the angle between the extension direction of the gold wire and the welding end of the welding end bracket and the plane where the welding end bracket is located is less than 20°.

[0017] In one embodiment of this utility model, the gold wire is welded to the upper surface of the LED chip and extends vertically upward to form a vertical extension segment. The upper end of the vertical extension segment bends downward and bends to connect with one end of the horizontal segment.

[0018] In one embodiment of this utility model, the upper end face of the welding end bracket is provided with a receiving groove, the receiving groove is in the shape of a trumpet with a large opening and a small bottom, and the other end of the gold wire is fixed in the receiving groove by solder welding.

[0019] In one embodiment of the present invention, an extension tube section is provided at the opening of the receiving groove, an opening is provided on the wall of the extension tube section, the gold wire passes through the opening, and a cover is provided at the opening of the extension tube section, the end of the cover extending into the cavity of the extension tube section abutting against the gold wire.

[0020] Another objective of this utility model is to provide an LED module, which includes the gold wire connection structure described above, and further includes...

[0021] A white shell with a viewing window is provided on it. The fixed end bracket and the welding end bracket are installed on the white shell and the LED chip is exposed in the viewing window.

[0022] Compared with existing technologies, the beneficial effects of this utility model are reflected in the following: Since at least a portion of the gold wire is parallel to and close to the surface where the welding end support is located, when the encapsulating colloid changes volume due to temperature changes, the tensile stress on the gold wire is smaller. Compared with the traditional structure, this layout reduces the stress concentration caused by the thermal expansion and contraction of the encapsulating colloid, reduces the risk of breakage of the solder joint or gold wire due to stress concentration, and significantly improves the reliability of the LED module in temperature change environments.

[0023] The gold wires arranged parallel to and close to the welding end support have a significantly reduced deformation when heated. According to the thermal stress theory, this effectively avoids the additional stress caused by excessive deformation of the gold wires, alleviates stress fatigue of the gold wires under the dual effects of thermal expansion and contraction and tensile stress of the encapsulating colloid, and further reduces the risk of gold wire breakage. Attached Figure Description

[0024] Figure 1 This is a front view of an LED module in the prior art;

[0025] Figure 2 This is a front view of an LED module in one embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the LED module in one embodiment of the present invention;

[0027] Figure 4 This is a top view of an LED module in one embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the structure of the LED module after the gold wire is removed in one embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of the LED module after the gold wire and extension tube section are removed in one embodiment of the present invention;

[0030] Explanation of icon numbers:

[0031] 10. Fixed end bracket;

[0032] 20. LED chip; 21. Welding notch; 211. Flow channel;

[0033] 30. Welding end support; 31. Receiving groove; 32. Extension pipe section; 321. Opening; 322. Cover;

[0034] 40. Gold line; 41. Horizontal segment;

[0035] 50. White shell; 51. Window. Detailed Implementation

[0036] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0037] The illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. Therefore, the drawings only show the components related to this utility model and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0038] It should be noted that in the LED module manufacturing process, traditional gold wire bonding technology generally uses a relatively high curvature. When the ambient temperature of the LED module rises, the gold wire with a high curvature will undergo significant deformation due to heat. According to the theory of thermal stress, this significant deformation will further increase the stress inside the gold wire. During repeated temperature changes, the gold wire is subjected to the combined effects of thermal expansion and contraction and the tensile stress of the encapsulating colloid, significantly increasing the risk of breakage due to stress fatigue. Therefore, existing gold wire connection structures and processes for LED modules have significant defects, and a new gold wire connection structure and related technologies are urgently needed to effectively solve the reliability problem of gold wire connections in small-sized LED modules under temperature variation environments. To address this, a gold wire connection structure for an LED module is proposed, comprising: a fixed end bracket 10; an LED chip 20 disposed on the fixed end bracket 10; a welding end bracket 30; and a gold wire 40, with both ends electrically connected to the LED chip 20 and the welding end bracket 30 respectively. The fixed surface of the LED chip 20 is coplanar with the fixed surface of one end of the gold wire 40 located on the welding end bracket 30. At least a portion of the gold wire 40 is arranged parallel to and adjacent to the surface of the welding end bracket 30.

[0039] In one embodiment, the gold wire 40 is made of pure gold material and generally has a diameter of 1.0 mil. After one end of the gold wire 40 is soldered to the upper position of the LED chip 20 by a wire bonding machine, the shape is adjusted so that at least a portion of the gold wire 40 is parallel to and close to the surface of the welding end bracket 30. Then, the other end of the gold wire 40 is soldered to the welding end bracket 30 by the wire bonding machine, thereby fixing both ends of the gold wire 40. After a set is debugged and the extension direction and arrangement of the gold wire 40 are qualified, large-scale production can be carried out.

[0040] In one embodiment, after the gold wire 40 is shaped by the wire bonding machine, a horizontal segment 41 is formed on the gold wire 40. The horizontal segment 41 is parallel to the plane where the welding end support 30 is located, and the horizontal segment 41 is arranged close to the welding end support 30.

[0041] See Figure 1 Existing traditional gold wire bonding typically uses a high curvature, resulting in a large span and a significant amount of suspended gold wire. This also makes it easier for stress from thermal expansion and contraction to concentrate at the neck. When glue is applied to window 51 of the white shell 50, thermal expansion and contraction cause the gold wire 40 to stretch and deform, leading to breakage. (See also...) Figure 2 The horizontal segment 41 of this invention effectively reduces stress concentration caused by thermal expansion and contraction of the encapsulant, making the gold wire 40 more parallel to the substrate surface, thereby effectively reducing stress concentration points. Furthermore, since the thermal deformation of the encapsulant near the substrate surface is small, the optimized wire bonding method can reduce stress caused by thermal expansion of the encapsulant, improve the stability of the gold wire connection, and make the LED module more durable during long-term use, reducing the problem of wire breakage caused by temperature changes.

[0042] In one embodiment, the ratio of the length of the horizontal segment 41 to the span distance between the two welding ends of the gold wire 40 is greater than or equal to 1 / 4.

[0043] See Figure 2 In the figure, the span distance between the two welding ends of the gold wire 40 is H, which is the distance between the welding point of one end of the gold wire 40 and the fixed end bracket 10 and the projection of the other end of the gold wire 40 and the welding end bracket 30 perpendicular to the fixed end bracket 10. The length of the horizontal segment 41 is at least 1 / 4 of the span distance H.

[0044] In one embodiment, to further reduce the deformation of the gold wire 40 due to thermal expansion, the distance between the horizontal segment 41 and the surface where the welding end support 30 is located is less than 0.5 mm.

[0045] Figure 2The less than 0.5 mm pitch h design significantly limits the deformation of the gold wire 40 when heated. Based on the principle of thermal expansion and contraction, when the LED module heats up due to high power operation or increased ambient temperature, the thermal expansion space of the gold wire 40, which is closer to the solder end bracket, is significantly compressed, effectively suppressing excessive bending and stretching of the gold wire 40. This effect greatly alleviates stress fatigue of the gold wire 40 during thermal expansion and contraction cycles, extends the service life of the gold wire, and improves the reliability of the LED module in high-temperature and frequently fluctuating temperature environments.

[0046] In one embodiment, the angle between the extension direction of the gold wire 40 and the welding end of the welding end bracket 30 and the plane where the welding end bracket 30 is located is less than 20°.

[0047] During LED module operation, temperature changes cause thermal expansion and contraction of the encapsulating colloid, which in turn introduces stress to the gold wire 40 and the solder joint. When the gold wire 40 is soldered to the solder joint support 30 at an angle of less than 20°, the stress generated by thermal expansion and contraction can be more evenly distributed along the solder joint, effectively preventing excessive stress concentration at the solder joint. Compared to soldering methods with an angle greater than 20°, this structure significantly reduces the peak stress borne by the solder joint, greatly reducing the possibility of cracking and desoldering due to stress concentration, improving the stability of the mechanical connection, extending the service life of the LED module, and ensuring its stable operation in complex environments.

[0048] In one embodiment, when the gold wire 40 is actually arranged, the gold wire 40 is welded to the upper surface of the LED chip 20 and extends vertically upward to form a vertical extension section. The upper end of the vertical extension section bends downward and bends to connect with one end of the horizontal section 41.

[0049] In one embodiment, to ensure the reliability of the welding between the gold wire 40 and the LED chip 20, a welding notch 21 is provided on the upper surface of the LED chip 20. The welding notch 21 is generally in the shape of a stepped shaft hole, with the upper opening being the larger end. At least four sets of flow channels 211 are provided around the welding notch 21 at intervals. One end of the gold wire 40 is fixed in the welding notch 21 by solder welding.

[0050] See Figure 5 The enlarged view shows that the welding notch 21 is shaped like a stepped shaft hole. The large upper opening increases the welding contact area between the gold wire 40 and the LED chip 20. When the LED module encounters temperature changes, compared to traditional planar welding methods, this increased contact area can more evenly distribute the stress generated by the thermal expansion and contraction of the encapsulant, reducing stress concentration at the solder joint. This effectively prevents the solder joint from cracking or detaching due to excessive stress, significantly enhances the stability of the mechanical connection, and extends the service life of the LED module.

[0051] See Figure 5 The enlarged view shows four sets of flow channels 211 spaced around the welding notch 21. During thermal expansion and contraction, these channels provide buffer space for the volume changes of the encapsulating colloid. When the colloid expands, some of it flows into the flow channels, reducing direct pressure on the gold wire 40 and the solder joint. When the colloid contracts, the colloid in the flow channels can, to some extent, fill the gaps created by the contraction, alleviate tensile stress, and further improve the stability of the mechanical connection.

[0052] In one embodiment, see Figure 6 The upper end face of the welding end bracket 30 is provided with a receiving groove 31. The receiving groove 31 is in the shape of a trumpet with a large opening and a small bottom. The other end of the gold wire 40 is fixed in the receiving groove 31 by welding with solder.

[0053] The horn-shaped receiving groove 31, with its large opening and small bottom, increases the welding area between the gold wire 40 and the welding end bracket 30. During the operation of the LED module, when encountering temperature fluctuations and thermal expansion and contraction of the encapsulating colloid, the larger welding area can evenly distribute tensile stress, reducing local stress concentration at the solder joint. Simulation tests show that compared to conventional planar welding, this significantly reduces the risk of solder joint cracking and detachment, and improves the mechanical stability of the connection between the gold wire and the welding end bracket.

[0054] The special horn-shaped structure is well-suited to the stress distribution characteristics. When the encapsulating colloid expands, the horn-shaped groove wall can guide the colloid to be evenly distributed, avoiding concentrated compression of the gold wires and solder joints. When the colloid shrinks, the space inside the groove can buffer the tensile force generated by the shrinkage. Together with the flow channel design at the LED chip soldering gap, it can comprehensively alleviate the stress on the gold wires and enhance the structural reliability of the LED module in complex environments.

[0055] In one embodiment, see Figure 5 In the enlarged view, an extension tube section 32 is provided at the opening of the receiving groove 31. An opening 321 is provided on the tube wall of the extension tube section 32. The gold wire 40 passes through the opening 321. A cover 322 is provided at the opening of the extension tube section 32. The end of the cover 322 that extends into the cavity of the extension tube section 32 abuts against the gold wire 40.

[0056] The gold wire 40 passes through the opening 321 in the wall of the extension tube section 32 and is fixed against the cover 322. This design effectively locks the position of the gold wire 40 at the soldering end. When the LED module is subjected to mechanical external forces such as vibration and impact, or when the encapsulating colloid expands and contracts due to temperature changes, the displacement of the gold wire 40 is strictly limited, avoiding additional stress caused by shaking. This greatly reduces the risk of the solder joint cracking or detaching due to mechanical stress concentration and stabilizes the connection between the gold wire 40 and the soldering end bracket 30.

[0057] The extension tube 32 and the cover 322 together create a closed space that buffers the direct compression and pulling of the encapsulating colloid on the gold wire 40 when the encapsulating colloid undergoes volume changes. Especially when the colloid shrinks, the cover 322's support against the gold wire 40, combined with the stress-dispersing effect of the flared receiving groove 31, further reduces the stress on the gold wire 40. Combined with the stress-relief design of the LED chip soldering notch 21, this comprehensively enhances the structural stability of the LED module under complex mechanical and thermal environments.

[0058] This utility model also proposes an LED module, which includes a gold wire connection structure in the LED module, and a viewing window 51 is provided on the white shell 50. The fixed end bracket 10 and the welding end bracket 30 are installed on the white shell 50 and the LED chip 20 is exposed in the viewing window 51. The specific structure of the gold wire connection structure is as described in the above embodiments. Since this LED module adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0059] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0060] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A gold wire connection structure in an LED module, characterized by, The LED module comprises: a fixed end support (10); an LED wafer (20) arranged on the fixed end support (10); a soldering end support (30); a gold wire (40) electrically connected to the LED wafer (20) and the soldering end support (30) at two ends, respectively, and a fixed surface of the LED wafer (20) is coplanar with a fixed surface on which one end of the gold wire (40) is located on the soldering end support (30). At least a part of a region of the gold wire (40) is arranged in parallel with and adjacent to a surface on which the soldering end support (30) is located.

2. The gold wire connection structure in the LED module according to claim 1, characterized by: The gold wire (40) extends a horizontal section (41) in parallel with the surface on which the soldering end support (30) is located.

3. The gold wire connection structure in the LED module according to claim 2, characterized by: A length of the horizontal section (41) is greater than or equal to 1 / 4 of a span between two soldering ends of the gold wire (40).

4. The gold wire connection structure in the LED module according to claim 2 or 3, characterized by: A distance between the horizontal section (41) and the surface on which the soldering end support (30) is located is less than 0.5 mm.

5. The gold wire connection structure in the LED module according to claim 1 or 2 or 3, characterized by: An angle between an extension direction in which the soldering end support (30) is located and the surface on which the soldering end support (30) is located is less than 20°.

6. The gold wire connection structure in the LED module according to claim 2, characterized by: The gold wire (40) is soldered to an upper end surface of the LED wafer (20) and extends vertically upward to form a vertical extension section, an upper end of the vertical extension section is bent downward and is bently connected to one end of the horizontal section (41).

7. The gold wire connection structure in the LED module according to claim 6, characterized by: An upper end surface of the soldering end support (30) is provided with a receiving groove (31) in a horn shape with a large aperture and a small bottom, and the other end of the gold wire (40) is soldered and fixed in the receiving groove (31).

8. The gold wire connection structure in the LED module according to claim 7, characterized by: An extension pipe section (32) is arranged at a groove opening position of the receiving groove (31), an opening (321) is arranged on a pipe wall of the extension pipe section (32), the gold wire (40) passes through the opening (321), a cover (322) is arranged at a pipe opening position of the extension pipe section (32), and an end portion of the cover (322) extending into a pipe cavity of the extension pipe section (32) abuts against the gold wire (40).

9. An LED module, characterized by: The LED module comprises the gold wire connecting structure in the LED module according to any one of claims 1 to 8, and further comprises a white shell (50) provided with a window (51), the fixed end support (10) and the soldering end support (30) are mounted on the white shell (50), and the LED wafer (20) is exposed in the window (51).

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