LED MODULE

Abstract

A LED module includes a substrate, a LED chip supported on the substrate, a metal wiring installed on the substrate, the metal wiring including a mounting portion on which the LED chip is mounted, an encapsulating resin configured to cover the LED chip and the metal wiring, and a clad member configured to cover the metal wiring to expose the mounting portion, the encapsulating resin arranged to cover the clad member.

Claims

1-24. (canceled)

25. A LED module comprising: a substrate; a first electrode supported by the substrate and having a first top surface; a LED chip disposed on the first top surface of the first electrode; a first insulating layer disposed on the first top surface of the first electrode and apart from the LED chip; a second electrode supported by the substrate and having a second top surface; a wire, which interconnects the LED chip and the second electrode, having a first portion contacting the LED chip and a second portion contacting the second electrode; and a resin covering the first top surface of the first electrode, the second top surface of the second electrode, the LED chip, the wire, and the first insulating layer.

26. The LED module of claim 25, wherein the first top surface of the first electrode includes a mounting portion on which the LED chip is mounted, wherein the second top surface of the second electrode includes a wire bonding portion spaced apart from the mounting portion, wherein the second portion of the wire is in contact with the wire bonding portion, and wherein the LED module further comprises a second insulating layer arranged to cover the second electrode to expose the wire bonding portion.

27. The LED module of claim 26, wherein the first electrode is formed to cover a first edge of the substrate in a first direction, wherein the second electrode is formed to cover a second edge of the substrate opposite the first edge, and wherein the resin is shorter than the substrate.

28. The LED module of claim 27, wherein the substrate includes a pair of concave portions formed at opposite ends of the substrate, the pair of concave portions depressed toward one another, the first electrode and the second electrode arranged to cover the pair of the concave portions, the resin formed to expose the pair of the concave portions.

29. The LED module of claim 27, wherein one end of the first insulating layer and a first end of the resin are at the same position in the first direction.

30. The LED module of claim 27, wherein one end of the first insulating layer extends toward a first end of the substrate further than a first end of the resin in the first direction.

31. The LED module of claim 29, wherein one end of the second insulating layer and a second end of the resin are at the same position in the first direction.

32. The LED module of claim 29, wherein one end of the second insulating layer extends further toward a second end of the substrate than a second end of the resin in the first direction.

33. The LED module of claim 27, wherein the resin is formed to cover entire width of the substrate in a second direction orthogonal to the first direction, opposite ends of the insulating layer and opposite ends of the substrate being at the same positions in the second direction.

34. The LED module of claim 25, wherein the substrate is formed longer than the resin in a first direction, a first side surface of the resin inclining toward a second side surface in the first direction.

35. The LED module of claim 34, wherein the first side surface of the resin includes an inclined surface inclined 6 degrees or more with respect to a thickness direction of the substrate.

36. The LED module of claim 34, wherein the first side surface of the resin has a curved surface.

37. The LED module of claim 34, wherein the second side surface of the resin inclines toward the first side surface in the first direction.

38. The LED module of any one of claim 37, wherein the second side surface of the resin includes an inclined surface inclined 6 degrees or more with respect to a thickness direction of the substrate.

39. The LED module of claim 38, wherein the second side surface of the resin has a curved surface.

40. The LED module of claim 25, wherein the first insulating layer is made of a material with which the adhesion strength between the first insulating layer and the first electrode and the adhesion strength between the first insulating layer and the resin become greater than the adhesion strength between the first electrode and the resin.

41. The LED module of claim 25, wherein each of the first electrode and the second electrode includes a gold-plated layer.

42. The LED module of claim 41, wherein the first insulating layer is made of a resin.

43. The LED module of claim 43, wherein the first insulating layer has a white color.

44. The LED module of claim 25, wherein the first insulating layer has a thickness of 1 m to 10 m.

45. The LED module of claim 25, wherein the substrate has an elongated shape extending in a first direction, and wherein a pair of concave portions depressed in the first direction is formed in opposite end portions of the substrate in the first direction.

46. The LED module of claim 45, wherein the first electrode and the second electrode are spaced apart from each other in the first direction and arranged at opposite edges of the substrate.

47. The LED module of claim 45, wherein the first top surface of the first electrode includes a mounting portion on which the LED chip is mounted, a first end portion covering a first end portion of the substrate, and a first narrow band portion protruding from the first end portion of the first top surface toward the first direction and connected to the mounting portion.

48. The LED module of claim 47, wherein a length of the mounting portion in a second direction orthogonal to the first direction is larger than a length of the first narrow band portion in the second direction.

49. The LED module of claim 48, wherein the length of the mounting portion in the second direction is shorter than a length of the first end portion of the first top surface in the second direction.

50. The LED module of claim 47, wherein the first insulating layer is disposed on at least a part of the first end portion of the first top surface and at least a part of the first narrow band portion.

51. The LED module of claim 50, wherein the at least a part of the first narrow band portion is fully covered in a second direction orthogonal to the first direction by the first insulating layer.

52. The LED module of claim 45, wherein the second top surface of the second electrode includes a second end portion covering a second end portion of the substrate, and a second narrow band portion protruding from the second end portion of the second top surface.

53. The LED module of claim 52, wherein a length of the second end portion of the second top surface in a second direction orthogonal to the first direction is larger than a length of the second narrow band portion in the second direction.

54. The LED module of claim 52, further comprising a second insulating layer disposed on at least a part of the second end portion of the second top surface and at least a part of the second narrow band portion.

55. The LED module of claim 47, wherein the first insulating layer is formed on the first electrode so as to extend from the concave portion side to the first narrow band portion in the first direction, and in at least a part of the first narrow band portion, and wherein the first insulating layer fully covers the first narrow band portion in a second direction orthogonal to the first direction.

56. The LED module of claim 25, wherein the first top surface of the first electrode includes a first portion and a second portion, the first portion being closer to an edge of the substrate than the second portion in a first direction, and wherein a length of the first portion in a second direction orthogonal to the first direction is larger than a length of the second portion in the second direction.

57. The LED module of claim 56, wherein the first insulating layer is formed to cover at least a part of the second portion of the first electrode, and at least a part of a top surface of the substrate.

58. The LED module of claim 25, wherein the first insulating layer includes a first portion covered by the resin and a second portion not covered by the resin.

59. The LED module of claim 25, wherein at least one of the first electrode and the second electrode includes a portion extending from a top surface of the substrate to a bottom surface of the substrate.

60. The LED module of claim 25, wherein the first insulating layer is disposed apart from a first edge of the substrate in a first direction.

61. The LED module of claim 60, wherein the first insulating layer extends from a second edge of the substrate to a third edge of the substrate in a second direction orthogonal to the first direction.

62. The LED module of claim 25, wherein at least one of the first electrode and the second electrode includes gold.

63. The LED module of claim 25, wherein at least one of the first electrode and the second electrode is subjected to a plating treatment.

64. The LED module of claim 25, wherein the resin is made of an epoxy resin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features and advantages of the present disclosure will become more apparent from the following detailed description of some embodiments made in conjunction with the accompanying drawings.

[0031] FIG. 1 is a plan view showing a LED module according to a first embodiment of the present disclosure.

[0032] FIG. 2 is a section view taken along line II-II in FIG. 1.

[0033] FIG. 3 is a plan view of the LED module shown in FIG. 1, with an encapsulating resin omitted for clarity.

[0034] FIG. 4 is a plan view showing a LED module according to a second embodiment of the present disclosure, with an encapsulating resin omitted for clarity.

[0035] FIG. 5 is a section view showing a LED module according to a third embodiment of the present disclosure.

[0036] FIG. 6 is a section view showing a LED module according to a fourth embodiment of the present disclosure.

[0037] FIG. 7 is a section view showing a LED module according to a fifth embodiment of the present disclosure.

[0038] FIG. 8 is a plan view showing a LED module according to a sixth embodiment of the present disclosure, with an encapsulating resin omitted for clarity.

[0039] FIG. 9 is a plan view showing a LED module according to a seventh embodiment of the present disclosure, with an encapsulating resin omitted for clarity.

[0040] FIG. 10 is a section view illustrating one example of conventional LED modules.

DETAILED DESCRIPTION

[0041] Some embodiments of the present disclosure will now be described in detail with reference to the drawings.

[0042] FIGS. 1 through 3 show a LED module according to a first embodiment of the present disclosure. The LED module A1 shown in FIGS. 1 through 3 includes a substrate 1, a metal wiring 2, a LED chip 3, an encapsulating resin 4, a wire 5 and a clad member 6. In FIG. 3, the encapsulating resin 4 is omitted to illustrate the interior of the LED module A1. The x, y and z directions indicated in FIGS. 1 through 3 are orthogonal to one another. The z direction is the thickness direction of the substrate 1. In the following description, the upper surface of the substrate 1 in the z direction in FIG. 2 will be referred to as a front surface, the lower surface as rear surface and the opposite end surfaces in the x direction as side surfaces.

[0043] The substrate 1 is made of, e.g., a glass epoxy resin. When seen in the z direction as in FIG. 3, the substrate 1 has an elongated rectangular shape extending in the x direction. A pair of concave portions 1a depressed in the x direction is formed in opposite end portions of the substrate 1 in the x-direction. The substrate 1 is manufactured, for example, by cutting a substrate material. In the manufacturing process, a plurality of through-holes is formed in the substrate material. The concave portions 1a are formed by cutting the through-holes.

[0044] The metal wiring 2 includes a metal electrode 21 and a metal electrode 22. The metal electrode 21 and the metal electrode 22 are spaced apart from each other in the x-direction and arranged at opposite edges of the substrate 1. Each of the metal electrodes 21 and 22 covers a region extending from the front surface of the substrate 1 to the rear surface across the side surface. In the present embodiment, the metal electrodes 21 and 22 cover only the concave portions 1a of the side surfaces of the substrate 1. The regions of the metal electrode 21 and the metal electrode 22 positioned on the front surface of the substrate 1 are used in mounting the LED module A1 to a desired circuit board as described earlier.

[0045] As shown in FIG. 3, the metal electrode 21 includes a region covering the left end portion of the substrate 1 over the full width in they direction. The metal electrode 21 further includes a narrow band portion 211 protruding from the region toward the x-direction, which is the right direction in FIG. 3. In addition, a mounting portion 212 connected to the right end of the narrow band portion 211 in the x-direction is also included in the metal electrode 21. In the example shown in FIG. 3, the mounting portion 212 has a square shape when seen in the z direction. The length of one side of the mounting portion 212 is larger than the length of one side of the LED chip 3 but is smaller than the y-direction width of the substrate 1. The narrow band portion 211 is formed such that the y-direction width thereof becomes smaller than the length of one side of the mounting portion 212.

[0046] As illustrated in FIG. 3, the metal electrode 22 includes a region covering the right end portion of the substrate 1 over the full width in they direction and a narrow band portion 221 protruding from the region toward the x-direction, which is the left side in FIG. 3. In the example illustrated in FIG. 3, the y-direction width of the narrow band portion 221 is smaller than the length of one side of the mounting portion 212. The right end in FIG. 3 of the wire 5 is connected to the narrow band portion 221. The section of the narrow band portion 221 not covered with the clad member 6 corresponds to a wire bonding section referred to in the present disclosure.

[0047] While omitted in the example shown in FIG. 2, the metal wiring 2 is formed of a plurality of metal layers laminated one above another. Among the metal layers, the outermost metal layer is formed of gold. The metal wiring 2 can be formed by subjecting the afore-mentioned substrate material to a plating treatment and etching away unnecessary portions. At this time, a structure in which the metal wiring 2 covers the concave portions 1a can be easily realized by performing the plating treatment to cover the inner circumferential surfaces of the through-holes formed in the substrate material.

[0048] The LED chip 3 is, e.g., a pn-type semiconductor device, and is configured to emit visible light or infrared light. The LED chip 3 has an n-side electrode formed on the lower surface thereof in FIG. 2. The n-side electrode is electrically connected to the mounting portion 212 through a silver paste which is not shown. The LED chip 3 has a p-side electrode formed on the upper surface thereof in FIG. 2. The p-side electrode is electrically connected to the narrow band portion 221 through the wire 5.

[0049] The encapsulating resin 4 is provided to protect the LED chip 3 and the wire 5, and is formed of, e.g., an epoxy resin transparent to the light emitted from the LED chip 3. The x-direction length of the encapsulating resin 4 is smaller than the x-direction length of the substrate 1. The y-direction length of the encapsulating resin 4 is equal to the y-direction length of the substrate 1. As shown in FIG. 1, the encapsulating resin 4 has an x-direction left end 4a positioned at the right side of the left concave portion 1a of the substrate 1 and an x-direction right end 4b positioned at the left side of the right concave portion 1a of the substrate 1. As shown in FIG. 2, the x-direction left side surface 41 of the encapsulating resin 4 is an inclined surface, which is positioned to the x-direction right side as it extends toward the upper side in the z direction. The side surface 41 is inclined 6 degrees or more with respect to the z direction. The x-direction right side surface 42 of the encapsulating resin 4 is an inclined surface, which is positioned at the x-direction left side as it extends toward the upper side in the z direction. The side surface 42 is inclined 6 degrees or more with respect to the z direction. The encapsulating resin 4 can be formed by a transfer molding method. The transfer molding method includes a step of installing the afore-mentioned substrate material in a mold and filling a molten resin into the mold and a step of pulling the mold and the substrate material apart after the resin is cured. The wire 5 is made of gold and is formed through the use of, e.g., a commercially available wire bonding capillary.

[0050] As shown in FIG. 2, the clad member 6 covers the metal wiring 2 and is covered with the encapsulating resin 4. The clad member 6 is made of a material with which the adhesion strength between the clad member 6 and the metal wiring 2 and the adhesion strength between the clad member 6 and the encapsulating resin 4 become greater than the adhesion strength between the metal wiring 2 and the encapsulating resin 4. For example, the clad member 6 may be a resin film having a z-direction thickness of 1 m to 10 m. As the resin film, it is possible to use, e.g., a resist employed in an etching process. It may also be possible to use a solder resist employed in a soldering process. If a white resist is used as the clad member 6, it becomes easy for the clad member 6 to reflect the light emitted from the LED chip 3. For that reason, the use of the white resist as the clad member 6 may provide an effect of increasing the quantity of light emitted in the z direction from the LED module A1.

[0051] In the example shown in FIG. 3, the clad member 6 is formed at least in a region other than a region where the LED chip 3 is die-bonded and a region where the wire 5 is bonded. The clad member 6 includes a first clad member 61 and a second clad member 62 spaced apart from each other in the x direction. As shown in FIG. 3, the first clad member 61 is formed into an elongated rectangular shape extending in the y direction when seen in the z direction. The y-direction length of the first clad member 61 is smaller than the y-direction length of the substrate 1. The x-direction right end portion of the first clad member 61 partially covers the narrow band portion 211. As shown in FIG. 2, the x-direction left end 61a of the first clad member 61 lies in the same position as the x-direction left end 4a of the encapsulating resin 4 in the x direction.

[0052] As shown in FIG. 3, the second clad member 62 is formed into an elongated rectangular shape extending in they direction when seen in the z direction. The y-direction length of the second clad member 62 is smaller than the y-direction length of the substrate 1. The x-direction left end portion of the second clad member 62 partially covers the narrow band portion 221. As shown in FIG. 2, the x-direction right end 62a of the second clad member 62 lies in the same position as the x-direction right end 4b of the encapsulating resin 4 in the x direction. In addition, the first clad member 61 is formed to cover not only the upper surface in FIG. 2 of the metal electrode 21 of the metal wiring 2 but also the front surface of the substrate 1. The second clad member 62 is formed to cover not only the upper surface in FIG. 2 of the metal electrode 22 of the metal wiring 2 but also the front surface of the substrate 1.

[0053] Next, description will be made on the operation of the LED module A1.

[0054] In the LED module A1 set forth above, the clad member 6 is provided between the metal wiring 2 and the encapsulating resin 4. As stated in the description of the example, if a gold layer is formed on the surface of the metal wiring 2, it causes a problem in that the metal wiring 2 and the encapsulating resin 4 are not easily bonded to each other, while it provides superior conductivity. In the LED module A1, an attempt is made to solve the problem by inserting the clad member 6 between the metal wiring 2 and the encapsulating resin 4. Thus the LED module A1 has a configuration that is easy to enhance the reliability thereof.

[0055] In the LED module A1, the side surfaces 41 and 42 of the encapsulating resin 4 are formed of inclined surfaces. This helps to prevent the encapsulating resin 4 from being caught in a mold when pulling the mold apart from the substrate material after a resin is cured in a transfer molding method. If the encapsulating resin 4 is caught in the mold, a force is applied for a long period of time in a direction in which the encapsulating resin 4 and the substrate 1 are pulled apart from each other. This increases the risk of causing exfoliation of the encapsulating resin 4 from the metal wiring 2. The LED module A1 is capable of preventing such problem and, therefore, has a configuration that assists in enhancing the reliability thereof.

[0056] In the example shown in FIG. 3, the y-direction length of the clad member 6 is smaller than the y-direction length of the substrate 1. Alternatively, the y-direction length of the clad member 6 may be equal to the y-direction length of the substrate 1.

[0057] In the embodiment described above, the clad member 6 does not protrude outward from the encapsulating resin 4. Alternatively, the clad member 6 may protrude outward from the encapsulating resin 4.

[0058] FIGS. 4 through 9 show other embodiments of the present disclosure. In these figures, the components identical with or similar to those of the foregoing embodiment will be designated by the same reference symbols as used in the foregoing embodiment. Description of these components will be omitted, if appropriate.

[0059] FIG. 4 shows a LED module A2 according to a second embodiment of the present disclosure. The LED module A2 shown in FIG. 4 differs in shape from the clad member 6 from the LED module A1. Other configurations of the LED module A2 remain the same as those of the LED module A1. FIG. 4 is a plan view of the LED module A2 with the encapsulating resin 4 thereof omitted for clarity.

[0060] As shown in FIG. 4, the clad member 6 of the present embodiment is formed to cover almost all portions of the substrate 1 except the opposite end portions thereof when seen in the z direction. The clad member 6 includes an opening 63 through which the mounting portion 212 is partially exposed and a recess 64 through which the narrow band portion 221 is partially exposed.

[0061] In a region other than the regions where the opening 63 and the recess 64 are formed, the clad member 6 of the LED module A2 covers the substrate 1 over the full length in the y-direction. In the x-direction opposite ends 65 and 66 of the clad member 6 may overlap with the x-direction opposite ends (see 4a and 4b in FIG. 1) of the encapsulating resin 4 which is not shown. The clad member 6 may protrude outward from the encapsulating resin 4.

[0062] In the example shown in FIG. 4, the opening 63 has a circular shape when seen in the z direction. The four corners of the mounting portion 212 are covered with the clad member 6. The size of the opening 63 may be set to have an area great enough to permit installation of the LED chip 3 and can be changed, if appropriate.

[0063] In the example shown in FIG. 4, the recess 64 is formed so that it can be depressed from the x-direction right end 66 of the clad member 6 toward the x-direction left side. The recess 64 may expose the narrow band portion 221 over an area only required in bonding the wire 5 to the narrow band portion 221. The shape of the recess 64 can be changed, if appropriate.

[0064] The clad member 6 may be greater in the reflectance of the light emitted from the LED chip 3 than the substrate 1. As shown in FIG. 4, the front surface of the substrate 1 is covered with the clad member 6. The clad member 6 employed in the present embodiment has a relatively high reflectance. Therefore, as compared with when the front surface of the substrate 1 is not covered with the clad member 6, it is possible to enhance the light extraction efficiency. On the contrary, if the reflectance of the clad member 6 is smaller than that of the substrate 1, the area of the front surface of the substrate 1 covered with the clad member 6 may be made smaller as is the case in FIG. 1, or the clad member 6 may be formed to cover only the upper surface of the metal wiring 2 as is illustrated in FIG. 9.

[0065] FIG. 5 shows a LED module A3 according to a third embodiment of the present disclosure. In the LED module A3 shown in FIG. 5, the edges of the encapsulating resin 4 are formed into a round shape. Other configurations of the LED module A3 remain the same as those of the LED module A1.

[0066] In the present embodiment, curved surfaces 43 and 44 are provided between the side surfaces 41 and 42 and the z-direction upper surface of the encapsulating resin 4 in FIG. 5. By providing the curved surfaces 43 and 44, it is possible to provide an effect of further reducing a resistance when the encapsulating resin 4 is pulled out from the mold.

[0067] FIG. 6 shows a LED module A4 according to a fourth embodiment of the present disclosure. In the LED module A4 shown in FIG. 6, the clad member 6 is formed to protrude from the encapsulating resin 4. Other configurations of the LED module A4 remain the same as those of the LED module A3.

[0068] As shown in FIG. 6, the left end 61a of the first clad member 61 is positioned at the left side of the left end 4a of the encapsulating resin 4 in the x direction. In the example shown in FIG. 6, the left end 61a of the first clad member 61 reaches the left end of the metal wiring 2. Alternatively, the left end 61a of the first clad member 61 may be positioned between the left end 4a of the encapsulating resin 4 and the left end of the metal wiring 2.

[0069] The right end 62a of the second clad member 62 is positioned at the right side of the right end 4b in FIG. 6 of the encapsulating resin 4 in the x direction. In the example shown in FIG. 6, the right end 62a of the second clad member 62 reaches the right end of the metal wiring 2. Alternatively, the right end 62a of the second clad member 62 may be positioned between the right end 4b of the encapsulating resin 4 and the right end of the metal wiring 2.

[0070] FIG. 7 shows a LED module A5 according to a fifth embodiment of the present disclosure. In the LED module A5 shown in FIG. 7, the clad member 6 is formed to be embedd ed into the encapsulating resin 4. Other configurations of the LED module A5 remain the same as those of the LED module A3.

[0071] As shown in FIG. 7, the left end 61a of the first clad member 61 is positioned at the right side of the left end 4a of the encapsulating resin 4 in the x direction. The right end 62a of the second clad member 62 is positioned at the left side of the right end 4b of the encapsulating resin 4 in the x direction.

[0072] FIG. 8 shows a LED module A6 according to a sixth embodiment of the present disclosure. In the LED module A6 shown in FIG. 8, an opening 67 having a circular shape when seen in the z direction is formed in place of the recess 64. Other configurations of the LED module A6 remain the same as those of the LED module A2.

[0073] With this configuration, the clad member 6 may cover the metal wiring 2 over a broader area, thereby further restraining exfoliation of the encapsulating resin 4.

[0074] FIG. 9 shows a LED module A7 according to a seventh embodiment of the present disclosure. In the LED module A7 shown in FIG. 9, the clad member 6 is formed to cover only the upper surface of the metal wiring 2. Other configurations of the LED module A7 remain the same as those of the LED module A1. As stated above, this configuration is effective when the clad member 6 is smaller in reflectance than the substrate 1.

[0075] The LED modules according to the present disclosure are not limited to the embodiments described above. The specific configurations of the respective parts of the LED modules according to the present disclosure may be modified to many different designs.

[0076] For example, while an example in which die-bonding and wire-bonding are performed has been described in the foregoing embodiments, the present disclosure may be applied to an embodiment in which wire-bonding portions are provided in left and right electrodes and in which a LED chip and two wire-bonding portions are connected to each other by wire bonding. Moreover, the present disclosure may be applied to an embodiment in which a LED chip is flip-chip connected to left and right electrodes. In any event, the clad member is formed in a region other than the connection portions of the LED chip and the metal wiring.

[0077] According to the above embodiments of the present disclosure, it is possible to ameliorate the problem of the metal wiring and the encapsulating resin being hard to be bonded to each other, because the clad member is inserted between the metal wiring and the encapsulating resin. According to some embodiments of the present disclosure, when manufacturing the LED module, it is easy to pull out the encapsulating resin from the mold after the encapsulating resin is formed through the use of the mold. This helps to reduce the force exerted between the encapsulating resin and the substrate and prevent exfoliation of the encapsulating resin from the metal wiring. Accordingly, the LED module provided by the present disclosure becomes highly reliable.

[0078] While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the novel LED modules described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.