Source: https://insight.rpxcorp.com/pat/US7078728B2
Timestamp: 2020-04-01 04:44:10
Document Index: 139776856

Matched Legal Cases: ['art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21', 'art 21']

Patent US 7,078,728 B2
a reflective frame having heat conductivity and fixed to the base within the mounting hole of the wiring board to surround the sealing member,wherein the reflective frame is disposed separately from the sealing member, andwherein heat generation from the light emitting element chip is released through both the base and the reflective frame.
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2. The surface-mounted LED according to claim 1, wherein said light emitting element chip is connected with the conductive patterns of the wiring board through electrical connection members, andwherein the conductive patterns include at ends thereof a plurality of electrical connection surfaces comprising terminal portions to supply a driving current for driving the light emitting element chip.
3. The surface-mounted LED according to claim 2, wherein the base is configured to release heat generated from the light emitting element chip to an outer surface of the base, andwherein electrical connection surfaces are disposed on an upper surface of the base.
4. The surface-mounted LED according to claim 2, wherein said wiring board is disposed to extend from an upper surface and around both ends of the base to one portion of the lower surface of the base, andwherein the electrical connection surfaces comprising the terminal portions are disposed to extend from an upper surface and around both ends of the base to a lower surface of the base.
the surface-mounted LED according to any one of claims 1 to 6;
further comprising a printed-circuit board including conductive patterns,wherein said conductive patterns of the printed-circuit board and electrical connection surfaces provided on the surface-mounted LED being connected mechanically and electrically by a fixing structure.
8. The light emitting device according to claim 7, further comprising a heat release member having heat conductivity,wherein said heat release member is fixed and thermally coupled with a peripheral portion of the reflective frame of the surface-mounted LED so that heat generated from the surface-mounted LED is released through the reflective frame and the heat release member.
9. The light emitting device according to claim 7, further comprising a heat release member having heat conductivity,wherein the base includes a heat releasing part,wherein said heat release member is fixed and thermally coupled with the heat releasing part of the base of the surface-mounted LED so that heat generated from the surface-mounted LED is released through the heat releasing part of the base and the heat release member.
10. The light emitting device according to claim 7, further comprising a first heat release member and a second heat release member which have heat conductivity,wherein the base includes a heat releasing part,wherein said first heat release member is fixed and thermally coupled with a peripheral portion of the reflective frame of the surface-mounted LED and said second heat release member is fixed and thermally coupled with the heat releasing part of the base of the surface-mounted LED so that heat generated from the surface-mounted LED is released through both the first heat release member and the second heat release member.
In FIG. 9, 1 is a conventional surface-mounted type light emitting element, 2a and 2b a pair of conductive members formed by a metal material having heat conductivity, 3 an insulative member for separating electrically and fixing the pair of conductive members 2a and 2b.
3a is a concave portion provided on an upper portion of the insulative member 3 so as to expose a portion of the conductive members 2a and 2b. is an LED chip which is mounted to straddle the pair of conductive members 2a and 2b exposed by the concave portion 3a of the insulative member 3, and is electrically connected and thermally coupled with the conductive members 2a and 2b. 5 is a transparent sealing member for sealing the LED chip 4. 6 is a printed-circuit board having conductive patterns 6a and 6b on which the light emitting element 1 is mounted.
Here, when a driving current is applied from the conductive patterns 6a and 6b to the LED chip 4, while the LED chip 4 emits light, simultaneously, the LED chip generates heat as a result of occurring power loss. The heat is transmitted efficiently to the conductive members 2a and 2b coupled thermally with the LED chip 4 and therefore if the printed-circuit board 6 is made of a material of excellent heat conductivity, it is possible to accomplish a good heat radiation effect.
Hereinafter, still another conventional light emitting element will be explained referring to FIG. 10. In FIG. 10, 10 is a conventional light emitting element, 11 a base, 12a and 12b lead frames. The base 11 and the lead frames 12a, 12b are made of the same material, the lowest surfaces of the base 11 and the lead frames 12a, 12b are positioned in the generally same level. 13 is an LED chip which is mounted on a bottom portion of the base 11 and coupled thermally with the base 11.
14a and 14b are wires comprising metal thin wires, which connect electrically an anode and a cathode of the LED chip 13 with the lead frames 12a and 12b. 15 is a transparent sealing member for sealing the base 11, the lead frames 12a, 12b, and the wires 14a, 14b together with the LED chip 13. 16 is a printed-circuit board on which the lead frames 12a, 12b are mounted through soldering 17. Here, because the lowest surface of the base 11 is positioned in the same level as that of the lead frames 12a, 12b, the base 11 is also fitted closely with the printed-circuit board 16 and fixed through the soldering 17, and the base 11 and the printed-circuit board 16 are thermally coupled.
In FIGS. 1 and 2, numeral 20 is a surface-mounted LED according to the present invention, 21 a generally rectangular shaped base having heat conductivity, whose material is preferably a metal material such as copper, aluminum, or the like, having good heat conductivity. 21a is a heat releasing part positioned on a lower surface of the base 21, and the heat releasing part 21a is thermally coupled with a heat release member separate from the heat releasing part 21a, as described hereinafter.
22 is a wiring board made of glass epoxy material or the like having heat insulation, which is thermally attached on an upper surface of the base 21 through an adhesive (not shown) applied on the upper surface of the base. 23 and 24 are two conductive patterns as conductive parts which are formed into a generally T-character shape on a surface of the wiring board 22 by a copper foil or the like. The conductive patterns 23 and 24 have at end portions thereof terminal portions 23a and 24a as electrical contact surfaces, respectively, which are connected electrically and mechanically with an outside printed-circuit board as described below. Here, the terminal portions 23a and 24a are disposed oppositely to the heat releasing part 21a on a lower surface of the base 21, in this case, the base 21 and the wiring board 22 are disposed between each of the terminal portions 23a and 24a and the heat releasing part 21a.
22a and 22b are two wiring board protrusions formed on the wiring board 22, which extend into a projected state from the vicinity of the terminal portions 23a and 24a of the conductive patterns 23 and 24 to the vicinity of center of the base 21. 22c is a mounting hole, which is formed by cutting out the wiring board 22 in a generally circular shape except for the wiring board protrusions 22a and 22b. 21b is a mounting area in which a substrate surface of the base 21 is exposed by the mounting hole 22c of the wiring board 22. 25 is an LED chip as a light emitting element chip, which is mounted on the mounting area 21b of the base 21 through, preferably an adhesive member (not shown) having heat conductivity.
As a result, the LED chip 25 is directly mounted on the basic surface of the base 21 and thermally coupled with the base 21. 26 is a generally cylindrical reflective frame made of an aluminum alloy or the like having heat conductivity and a high reflection coefficient. The reflective frame 26 is disposed on an outer periphery of the mounting area 21b exposed by the mounting hole 22c of the wiring board as described above to surround the periphery of the LED chip 25, and fixed by an adhesive or the like (not shown) to couple thermally with the base 21. 26a and 26b are reflective frame concave portions formed in a line state on a lower portion of the reflective frame 26, which form a mechanical and electrical non-contact structure by avoiding the wiring board protrusions 22a, 22b and the conductive patterns 23,24 formed on the wiring board protrusions 22a, 22b. Meanwhile, the reflective frame 26 is adapted to be seen through it in FIG. 2 for convenience of explanation.
23b and 24b are insulative resistors, which cover surfaces of the conductive patterns 23 and 24 close to the reflective frame concave portions 26a and 26b of the reflective frame 26 and secure electrical insulation of the reflective frame 26 and the conductive patterns 23, 24.
27a and 27b are two wires comprising metal thin wires as electrical connecting members, which connect electrically anode and cathode terminals (not shown) of the LED chip 25 with the conductive patterns 23, 24 on the wiring board protrusions 22a, 22b. In addition, gold plating is preferably provided on the surfaces of the conductive patterns 23, 24.
28 is a generally cylindrical transparent sealing member, which covers the LED chip 25, the wires 27a, 27b, and the wiring board protrusions 22a, 22b to protect mechanically them. Note that the sealing member 28 is omitted in FIG. 2.
In FIG. 3, the wiring board protrusions 22a and 22b extend from the vicinity of opposite end portions of the wiring board 22 passing through the lower portion of the reflective frame 26 to the vicinity of the center of the base 21 and are close to the LED chip 25.
The conductive patterns 23 and 24 on the wiring board protrusions 22a, 22b are also close to the LED chip 25 passing through the lower portion of the reflective frame 26. Meanwhile, because the reflective frame 26 avoids the wiring board protrusions 22a, 22b and the conductive patterns 23, 24 by the reflective frame concave portions 26a, 26b, the disposition of the wiring board protrusions 22a, 22b and the conductive patterns 23, 24 is not blocked by the reflective frame 26.
The anode and cathode terminals (not shown) of the LED chip 25 are electrically connected with the conductive patterns 23, 24 close to the LED chip 25 by the wires 27a, 27b, as described above.
26c is a reflective surface, which is provided in an inner surface of the reflective frame 26 close to the LED chip 25 and has radially an appropriate angle to reflect light released from the LED chip 25 and to collect the reflected light. The reflective surface 26c may be structured to further enhance reflective efficiency of light by providing bright plating thereon.
Subsequently, in FIG. 4, the reflective frame 26 is fixed on the periphery of mounting area 21b of the base 21, exposed by the mounting hole 22c of the wiring board 22 cut out in the generally circular shape, as described above. As a result, because the reflective frame 26 is fixed to the base 21 with a wide area, in an area other than the reflective frame concave portions 26a, 26b, the reflective frame 26 and the base 21 are thermally coupled, with a low thermal resistance.
When a driving voltage is applied to the terminal portions 23a and 23b, a driving current flows through the wires 27a and 27b to the LED chip 25. As a result, the LED chip 25 expends a power equal to amplification of the driving voltage and the driving current and a portion of energy becomes output light, which is emitted passing through the sealing member 28, while most of energy becomes heat which is generated from the LED chip 25.
Here, because the LED chip 25 is thermally coupled through the adhesive member having the heat conductivity with the base 21, as described above, heat generated from the LED chip 25 is transmitted effectively to the base 21. The heat transmitted to the base 21 is then transmitted effectively to the reflective frame 26 thermally coupled with the base 21. Moreover, if the heat release member having a relatively large heat release capacity is closely contacted with the heat releasing part 21a disposed on the lower surface of the base 21, it is possible to realize its heat release efficiency because the heat of the base 21 is transmitted to the heat release member. A detailed description on this will be described below. Furthermore, if the heat release member is closely contacted with the reflective frame 26, further efficient heat release can be accomplished.
As described above, according to the first embodiment of the present invention, because heat from the LED chip 25 can be released through both the heat conductive base 21 and the heat conductive reflective frame 26 thermally coupled with the base 21, the surface-mounted LED of a high heat release efficiency can be accomplished. Because the reflective surface 26c is formed on the inner surface of the reflective frame 26 to reflect and collect light efficiently from the LED chip 25, the surface-mounted LED having a high efficiency for emitting light can be accomplished.
Moreover, because the heat releasing part 21a positioned on the lower surface of the base 21 and the terminal portions 23a, 24a for connecting with the outside printed-circuit board are oppositely disposed, a heat release route from the LED chip 25 and a current supplying route to the LED chip 25 can be separated, a degree of freedom is increased to a heat release design and further a material of the substrate on which the surface-mounted LED is mounted is not limited. Also, the surface mounting of the surface-mounted LED can be mounted on the printed-circuit board, it is possible to correspond to efficiency of mounting operation and reduction of mounting area and so on.
The wiring board 22 is disposed to run around the heat releasing part 21a on the lower surface of the base 21 from both end surfaces 21c and 21d of the base 21. The conductive patterns 23 and 24 formed on the wiring board 22 are also disposed to run around the wiring board 22 and therefore terminal portions 23b and 24b as electrical connection surfaces are formed on the lower surface of the base 21. As a result, the terminal portions 23b and 24b are connected electrically and mechanically with the outside printed-circuit board by the surface-mounting, as described hereinafter, to enable a driving current to supply to the LED chip 25 by means of the terminal portions 23b and 24b. As described below, heat generated from the LED chip 25 can be released through the heat release member closely contacting with the reflective frame 26.
As described above, according to the second embodiment of the present invention, because the heat release route from the LED chip 25 is secured by the reflective frame 26 and the current supplying route to the LED chip 25 is secured by the terminal portions 23b and 24b disposed on the lower surface of the base 21, it is possible to provide the surface-mounted LED in which heat release is efficiently performed, the optimum for surface-mounting LED is accomplished, and a material for the substrate or board to mount the LED is not limited.
The printed-circuit board 41 has conductive patterns 41a each comprising a copper foil or the like and a mounting hole 41b which is generally circular. Here, the surface-mounted LED 20 is disposed to be fitted in the mounting hole 41b of the printed-circuit board 41, and the terminal portions 23a and 24a of the surface-mounted LED 20 and the conductive patterns 41a of the printed-circuit board 41 are electrically and mechanically connected by soldering 45 as connecting means.
A heat release member 42 is fixed to and thermally coupled with the heat releasing part 21a of the base 21 in the surface-mounted LED 20. 42a are a plurality of heat release concave portions which are arranged in a line state and which are disposed on a lower surface of the heat release member 42 and act to enlarge a surface area of the heat release member 42 and to enhance a heat release efficiency. The heat release member 43 also has a heat release hole 43a in which a peripheral portion of the reflective frame 26 of the surface-mounted LED 20 is fitted, to be fixed to the reflective frame 26 and be thermally coupled.
When a driving voltage is applied to the terminal portions 23a and 24a of the surface-mounted LED 20 through the conductive patterns 41a of the printed-circuit board 41, a driving current flows into the LED chip 25 to drive it and light 44 emitted from the LED chip passes through the sealing member 28 and is released from the heat release hole 43a of the heat release member 43. Scattered light 44a, which is one portion of the emitted light 44 and is emitted obliquely from the LED chip 25 is reflected on the reflective surface 26c of the reflective frame 26 and collected and emitted in a generally equal vertical direction with the emitted light 44 to become a strong light having a directivity.
Heat generated from the LED chip 25 is transmitted to the base 21 as a first heat release route, further is transmitted from the heat releasing part 21a of the base 21 to the heat release member 43 and then is released to an ambient layer of air and so on. As a second heat release route, heat from the LED chip 25 is transmitted from the base 21 to the reflective frame 26, further is transmitted to the heat release member 43 and then released to the ambient air layer and so on.
Because the scattered light 44a from the LED chip 25 is reflected on and concentrated by the reflective surface 26c of the reflective frame 26, the light emitting device having an improved characteristic of concentration and a preferable directivity can be accomplished. Moreover, if the bright plating is provided on the reflective surface 26c, as described above, reflectivity of the reflective surface 26c is further enhanced so that the light emitting device having higher output can be achieved.
Furthermore, because the terminal portions 23a and 24a of the surface-mounted LED 20 are provided on a surface of the base 21 opposite to the heat releasing part 21a, the printed-circuit board 41 connected with the terminal portions 23a and 24a is disposed in a remote position opposing to the heat releasing part 21a of the base 21, as a result, the printed-circuit board 41 has no role for releasing heat from the LED chip 25. Consequently, it is not required to use a high cost material such as a high conductive metal core substrate or the like for the printed-circuit board 41, because glass epoxy material or the like can be used, as a usual printed-circuit board, it is possible to have a high degree of freedom to selection of the substrate material and to accomplish cost down of the light emitting device.
Meanwhile, the heat release member 42 has the heat release concave portions 42a to have more efficient heat release effect, but the heat release member is not limited to the structure, the heat release concave portions 42a may not be required. Contrary, although the heat release concave portions 42 are not provided on the heat release member 43 as shown in FIG. 7, they may be provided on the heat release member 43 in order to have more efficient heat release effect.
The printed-circuit board 51 has conductive patterns 51a formed from copper foils or the like, and the terminal portions 23b and 24b provided on the lower surface of the surface-mounted LED 30 are connected electrically and mechanically with the conductive patterns 51a of the printed-circuit board 51 by soldering 53 as connection means. The heat release member 52 has a heat release hole 52a into which the peripheral portion of the reflective frame 26 in the surface-mounted LED 30 is fitted, and is fixed to and thermally coupled with the reflective frame 26.
When a driving voltage is applied through the conductive patterns 51a of the printed-circuit board 51 to the terminals portions 23b and 24b of the surface-mounted LED 30, a driving current flows through the LED chip 25 to drive it. Hereinafter, because an operation of the emitted light 44 from the LED chip 25 and the scattered light 44a is the same as that of the third embodiment, the description is omitted.
Meanwhile, in the surface-mounted LED of the present invention, a light scattering material, fluorescent particles, a dimmer material or the like can be included in the sealing member and so on for covering the LED chip. Consequently, a various of surface-mounted LEDs, in which directivity of emitted light and light emitting wave frequency are different, and a light emitting device for using each thereof can be provided. It is also possible to set finely the directivity of the emitted light by changing a height of the reflective frame 26, and an angle or a shape of the reflective surface 26c provided in the inner surface of the reflective frame 26.
Ishii, Hirohiko, Imai, Sadato
US 20050023538A1
438/22, 438/82, 438/98, 438/106, 438/249, 257/79, 257/80, 257/432
Surface Mounted Led And Light Emitting Device
Sponsoring Entity: Citizen Electronics Company Limited