* 1: Sharp originally scheduled time to market for July 15, 2009. But the company on July 9 issued a decision because of "scheduled than expected" and postponed the listing. Support dimmer, LED bulbs with dimming / toning capabilities will in the same year on September 1, the other LED light bulbs will be listed in the same year on August 1.
* 2: Lamp giant Matsushita in March 2009, although organized "Lighting Fair 2009" exhibition showcased reference bulb-type LED, but as of early August 2009, the company "has no specific plans to put into operation."
* 3: The composition of LED light in the ultraviolet region of the bulb is relatively small, and therefore also has the advantage of not sensitive to ultraviolet light to attract insects.
* 4: Increase the need to increase the surface area of the blade height, or narrow blade spacing (increasing the number of tablets). Toshiba Lighting in determining the spacing and height of the blade reference to the flow of air around the radiator (convection).
This will combine Toshiba Lighting products and LED bulbs dismantling Figure Sharp products, detailing its internal structure.
Toshiba and Sharp's new LED bulb Secret (2): The heat sink structure vary
LED light diffusion hemispherical portion is referred to as "a globe." Toshiba Lighting of a globe made of polycarbonate, the use of adhesive attachment to the 4 position of the top of the radiator. The spherical lampshade ordinary light bulb is usually glass. This is because the LED light is not easy to heat, so that the resin can be adopted. And, after using the resin, while the lamp is falling too easy to break, thereby improving safety.
A globe is disposed below the LED chip. Toshiba Lighting products, 6.9W (white, total luminous flux 565lm) Rated power products, LED package substrate on the number of LED is 7 (Fig. 3) * 5.
Figure 3: Toshiba Lighting LED bulbs LED substrate on the back of the upper part of the heat sink (housing) on the surface of the contact, the direct use of two screws.
Installed to connect the power cord connector on the circuit Toshiba Lighting's LED substrate. The connector is without welding products, estimated to be prioritized ease of assembly. Incidentally that Toshiba Lighting LED bulbs are factory assembled in Japan.
LED substrate by two screws, you can see on the surface of the substrate after removing the radiator. This part of the processing carried out by a mechanical flattening process, only the back surface of the LED substrate having the screw can be fixed to the substrate so as to obtain sufficient thermal bonding properties.
Spherical lampshade Sharp LED bulb for glass manufacturing * 6.7.5W (Daylight, total luminous flux 560lm) equipped with 6 LED package (Figure 4) rated power LED chip products. Backplane wiring between the power supply circuit connected by welding.
Figure 4: The upper part of the LED chip Sharp LED bulbs use three screws between the metal plate, both coated with a heat-conducting oil. Further, the power supply wiring circuit substrate were soldered.
LED substrate by three screws on the metal plate, coated with thermal grease (Grease) between them. Fixing the LED chip is not the aluminum alloy casting of the radiator, but another metal plate. Although the material is aluminum, but can not see the surface machining marks. This metal plate is fixed with LED substrate bonding properties between the two there may not be sufficient, so you need to use thermal grease.
A metal plate using three screws (not the LED substrate is fixed screws) is fixed to the heat sink. Remove the metal plate can be seen, the black resin is filled inside the radiator (FIG. 5) * 7. These resins are estimated to promote thermally conductive filler, the resin and the metal back of the plate does not contact, so presumably its main purpose is to loose
I was fortunate to participate in SHARP LED lamp design, following the metal plate is used for cooling, before considering to make a mold, but for ID needs, divided into two parts, fitted O-ring purpose is waterproof, plus vinyl purposes the power board is fully derived heat inside, often burning IC did not increase when the vinyl before.
New LED bulbs internal structure Secret (a): the lower half of the bulb for heat dissipation member
Figure 1: Low-cost LED bulbs Toshiba Lighting and Sharp have listed the price is about half of the past, namely the retail price of less than 4000 yen in ordinary light bulb-type LED lighting (LED bulbs). In order to prevent the light emission efficiency decreases, the life is shortened, the cooling LED is very important. Therefore, the lower LED bulbs into aluminum alloy casting radiator.
Light-emitting diode (LED) as a light source lighting equipment with low power consumption, long life gradually began to penetrate in the market. Which is intended to replace incandescent bulbs, compact fluorescent lamp bulbs and other traditional bulb-type LED lighting (hereinafter referred to as LED bulbs) recently is cause for concern. Because, according to LED bulb life calculation unit time prices have been comparable to conventional bulbs, so popularity is expected to accelerate in the ordinary family.
Pioneered low-cost LED bulbs manufacturer Sharp. Sharp on June 11, 2009 announced that the company will be less than the actual price of 4000 yen a low price as a selling point to enter the LED light bulb market. This price is set very impact, about half the time, the price of LED bulbs commercially available. In March 2009, Toshiba began selling LED bulbs lighting (Toshiba Lighting) responded quickly to the Sharp product released 11 days later, on June 22 released the same with Sharp listed in the July 15 New Low LED bulb * 1, * 2.
Lower half of the bulb for heat dissipation member
Low price of LED bulbs can be discarded does not mean low power consumption, long life and other unique advantages. Moreover, the products in order based on the market, but also has a high heat capacity.
LED light bulb in a small infrared ingredients. Therefore, incandescent bulbs, bulb-type fluorescent lamp compared with the light irradiation section 3 * warming slowly. But the LED itself may have a fever, so the heat countermeasures indispensable. Once the temperature exceeds the allowable LED chips, LED luminous efficiency will drop, for the life of the bulb will produce adverse effects.
From the outside, LED bulb features can be said to be the result of improved heat dissipation. Side view LED lamp, more than half of the entire lower side of the radiator (Figure 1). Toshiba Lighting, Sharp have adopted the aluminum alloy casting radiator.
Comparison of the two radiators, in addition to color, the shape of the difference is very obvious. Although Sharp products in terms of height a little more, but the channel area is larger radiator Toshiba lighting. Toshiba Lighting products channel depth from the bottom to gradually increase, while Sharp is down basic contour.
Surface area of the radiator, the higher cooling performance. In the case of limited dimensions, the channel depth is increased to increase the surface area of one method, but with the increase in channel depth, the power supply circuit substrate, a resin or the like installed inside the space of the housing will be reduced * 4.
Toshiba Lighting radiator internal space is cylindrical, Sharp product was close to the conical shape (Fig. 2). Resin, while maintaining the insulating shell, the bottom of the power supply circuit is mounted on the lamp housing.
Figure 2: The main structure of Toshiba Lighting LED bulbs LED bulbs heat sink (housing) of the cylindrical side of the right triangle has 16 channels, overlying circular plate. Fixed directly above the LED substrate. The power supply circuit plate is fixed to the cup-shaped resin case, and is inserted from the bottom of the radiator. On the other hand, the heat sink was Sharp LED bulb has tapered cylindrical shape, mounted on a surface 60 of the blade height of less than a few mm. LED substrate is fixed to the top of the radiator cover of a disk-shaped metal plate. The power supply circuit plate fixed above the heat sink insert conical (but most of the side of the hollow) A in the resin case.
LED chip is the largest source LED bulb, the bulb is the plurality of LED chips are packaged together, and then mounted on a substrate made of an aluminum alloy. This aluminum LED substrate is fixed to the upper part of the radiator. Sharp products, it is also sandwiched between the LED substrate and the heat sink metal plate.
This will combine Toshiba Lighting products and LED bulbs dismantling Figure Sharp products, detailing its internal structure.
New LED bulbs internal structure Secret (c): The power supply circuit size significantly different
The power supply circuit size significantly different
Radiator installed power supply circuit substrate and a resin shell. Figure 6 is a case of removing the Toshiba LED lighting beneath the metal lamp cover later. The power supply circuit is fixed on the base plate inserted in the resin radiator shell with a screw in.
Figure 6: Toshiba Lighting LED lamp power supply circuit of the lower plate is inserted in the resin shell. Resin shell use a screw on the radiator.
The power supply circuit phenolic paper plate is rectangular plate, the resin was close to the cylindrical shell (Fig. 7). Between the base plate and the heat sink is configured with a resin shell, ensure the insulation between them.
Figure 7: Toshiba Lighting LED bulb shell resin base resin and a power supply circuit only in case the metal cover side (right in the figure) have an open position, to ensure that the power supply circuit of the heat sink base plate and insulation. The power supply circuit plate is rectangular, with the LED through the connector base plate contact.
Figure 8 is a cross section of Sharp's LED bulbs radiator. Because filler material hard, clear from above, it takes a lot of time, thus directly cut the radiator.
Figure 8: section of the evaporator internal Sharp LED bulb is filled with a dense filler material, the power supply circuit plate and a resin shell is completely covered.
After the cut the radiator, with the gradual peeling a filler, a power supply circuit plate and the support plate of the resin case (hereinafter, the resin case A) the shape of gradually emerged (Fig. 9). The shape of the power supply circuit board backplane badminton racket, basically the same size as the inner diameter of the heat sink.
Figure 9: Sharp LED bulb power supply circuit after clearing floor filler plate installed on the power circuit components presented in front. Power circuit substrate was "board badminton racket" shape, extending to the bottom of the resin shell A (install metal lid) in.
Sharp's power circuit floor epoxy glass manufacturing, far greater than the Toshiba Lighting floor. This is due to the channel bottom size leads to highly restricted radiator? Or for the member and the plate size in the limited space in order to achieve optimum balance between cost and heat the power supply circuit is determined? These problems could not get an answer. But the sum of heat, generated by the power supply circuit substrate needs to transfer to a heat sink. Sharp said, "In order to achieve the support of E17 and E11 lamp holders and other small future, is currently exploring the miniaturization of the floor."
A resin case is retained only the cylindrical upper end and a lower end side of the ring to cut down. On the other side with the power circuit components with the larger opening, easy to conduct heat sink.
LED bulb assembly steps presumed as follows.
Toshiba Lighting processes as follows: ① in the radiator fixed resin shell (one screw); ② into the power circuit substrate; ③ install metal cover (including connecting wiring); ④ fixed LED substrate (2 screws); ⑤ use connector wiring; ⑥ connection spherical lampshade.
Sharp process is: ① the resin case is fixed on the heat sink B; (3 处 screws); ② A resin case is inserted in the radiator; ③ into the power circuit A of the base plate in the resin case; ④ metal cover is installed (including the connection wiring); ⑤ injecting filler material; ⑥ configuration O ring; ⑦ fixed metal plate (3 screws); ⑧ fixed LED substrate (3 screws); ⑨ wiring welding; ⑩ connection spherical lampshade.
Toshiba Lighting to the radiator as the center, to install different components in both directions up and down, Sharp uses a bottom-up approach to gradually install.
Sharp though the process more, but in China's factory-made, so the process is still viable, although many. Toshiba Lighting is factory assembled in Japan, so also need to consider reducing the number of parts and assembly steps from the cost.
New LED bulbs Secret internal structure (IV): a low-cost way to achieve change heat
Change cooling mode to achieve low cost
As described in the beginning of the article, as published in the stimulation of Sharp, Toshiba Lighting design by changing the original product to achieve a price reduction. Original product in August 2009 already available for purchase, in order to confirm the contents of the design change, the dismantling of the group also carried out on the original product dismantling * 8.
Only difference is the appearance of the upper radiator (between spherical lampshade) silver trim ring (Figure 10). Because silver trim ring to improve heat dissipation, improve the luminous efficiency without any help, so the new product omitted the ring. Although the radiator mold
Consequent need to modify, but considering the production of hundreds of thousands, omissions trim ring is more beneficial to reduce costs.
Figure 10: Comparison of new products Toshiba Lighting LED bulbs compared with the original product, in addition to the appearance of the paint color from white to silver, but also has nothing to do with the heat omitted decorative ring. (Click to enlarge)
Can not see the difference between the spherical lampshade off the original products and new products. However, removal of the metal cover, the difference is clear: the original product in the resin housing, the inner packing material is present power supply circuit plate (11). And the resin case, only the new product inserted into the power supply circuit substrate.
Figure 11: the lower part of Toshiba Lighting LED bulbs (original product) in order to make efficient heat conduction backplane power supply circuit to the radiator, full of filler material between the back plate and the heat sink. (Click to enlarge)
Unplug the resin can be seen from the radiator shell, resin shell length is shorter than the original product new product (Figure 12). Moreover, the side shell resin as well as new products, there is no open area. Its purpose is to make the shell with a filler material in contact with the heat sink.
Figure 12: There is an open site on Toshiba Lighting LED bulbs (original product) resin case and power supply circuit base resin shell, the inner surface of the filling material for contact with the heat sink. (Click to enlarge)
Why new products without filling stuff? Answer this regard, Toshiba Lighting are: ① the original product in parallel using a 6 chip LED package, and new products to the 3-chip series; ② power circuit output current is reduced, heat is also reduced; so the new product no longer use the filler plate heat conduction power circuit. Enlarge observe the LED package can actually see the difference on the number of chips. Save filling material injection step, the assembly costs can also be reduced accordingly.
Toshiba also said that changing the power supply circuit backplane also helps reduce costs. The new product uses a phenolic paper plate, while the original product is used in epoxy glass plate. According to those familiar with electronic circuitry saying: "Although the cost of the floor also has a relationship with the production, but this change alone can reduce the floor from 300 to 500 yen to about 50 yen."
Remove the bottom to see the actual, original product does epoxy glass plate. Compared with the new product phenolic paper plate, wiring phenolic paper is only one side of the floor, and epoxy glass substrate for both sides, so that the floor of the original product is small. That is, for the introduction of new products and expanded phenolic paper plate area, resin shell to accommodate the floor had increased.
This design change requires modification radiator mold, which is an increase in cost factor. But Toshiba said: "By changing the design, the amount of material used will be slightly lower radiator together, re-open mode can still reduce costs.."
Ceramic radiator
Stanley Electric is also one of the new companies into the market of LED bulbs. In the field of automotive lighting outstanding performance of the company plans to start mass production from September 2009 LED bulbs * 9. Because the dismantling of the company's production has not yet begun, so the physical dismantling of the group failed to disassemble, in this interview to be introduced to improve heat dissipation informed manner.
Stanley Electric biggest feature is the LED bulbs ceramic heat sink material (Figure 13). Because the ceramic to the air thermal conductivity higher than aluminum and Sharp, Toshiba Lighting used, so the heat sink area can be reduced.
However, from a cost point of view, the cost of aluminum alloy castings to be low, many manufacturers have therefore abandoned ceramics. But Stanley Electric has found great benefits brought by the narrow radiator: You can achieve full light.
Now, the use of aluminum alloy radiator LED bulbs LED settings must be close to the top position. Therefore, the light is difficult in the vicinity of the metal cap along the transverse divergence. Incandescent bulbs can not be the same as used in metal covered with a reflective plate lighting equipment, as well as the position of the lamp is set low and need full-luminous floor lamp lateral nearby. After the ceramic heat sink, LED's can be set close to the position of the metal cap, and thus meet the needs of the above uses, the difficulty of replacing incandescent bulbs decreases.
Stanley Electric LED substrate is made of aluminum alloy heat-conductive manner to the heat sink has been improved (Fig. 14). LED substrate is supported by the top flange of the inside of the ceramic radiator. Due to the small contact area, and therefore can not obtain sufficient to rely on the contact heat conduction. Moreover, the thermal conductivity of the ceramic surface to the air is high, but the low thermal conductivity of the ceramic interior, which also affect the thermal effects.
Figure 13: Stanley Electric LED light bulb through the use of high heat ceramic,
Radiator (housing) can be reduced, in addition to above, can also illuminate the surroundings.
Figure 14: Stanley Electric LED bulbs sectional diagram of the imagination because of the LED chip and radiator
The contact portion is not sufficiently heat conductive, and therefore the connection of the two internal filling of the filling material
For this purpose, the company internal filling the radiator type silicon material having a high thermal conductivity is filled, the back surface of the LED chip is also in contact with the filler material is realized. This improvement opened the LED substrate via a pathway to the ceramic radiator filler material efficient conduction of heat. To the back of the filling material in close contact with the LED base plate, the assembly method is accordingly improved.
As the production process of preparing to spend a lot of time, Stanley Electric failed to schedule production. Although production costs when determining the optimal balance point has been reached, but to achieve low-cost LED bulbs cost or time spent.
* 8: The basic price of the new product the same.
* 9: Stanley Electric in March 2009 was originally scheduled to release in May of the same year production of LED bulbs, but the plan was postponed to August the same year, the supply of samples, mass production in September of the same year. The company does not disclose sales of LED light bulbs, lighting fixtures sales undertaken by manufacturers and distributors.
New LED bulbs internal structure Secret (v): to improve the heat dissipation of the LED package
Improving heat dissipation of the LED package
Three companies described above are to improve the LED chip to the heat sink and thermal efficiency of the LED heat dissipation is improved. The common denominator in that the substrate is used with an insulating layer sandwiched between the aluminum alloy plate and the wiring pattern of the metal base plate. There is not much difference between the measures for the benefit of the LED chip to install parts of the thermal plate taken.
In the future, in order to achieve the brightness equivalent to 100W incandescent bulbs LED bulbs, and this difference needs to improve heat dissipation countermeasures. New LED package is one of countermeasures.
Tungsten Japan (Nippon Tungsten) developed a combination of a silver-plated copper lead frame and the housing is made of a ceramic LED package (Figure 15). The package is not installed as a chip LED chip plate suppliers.
Figure 15: Japanese tungsten LED package provided silver plated copper lead frame is fixed to the lower price of ceramic shell. Mainly by heat conduction to the heat sink of the lead frame.
In the past have had the use of high thermal conductivity aluminum nitride material products as LED encapsulation shell. LED's can use shell heat conduction to the package substrate. Although the housing can rely on thermal conductivity and heat resistance than the resin case features to achieve high power LED package, but the cost is expensive.
In contrast, Japan's chip packaging tungsten copper leadframe plate as heat conduction path, instead of the LED package housing. The shell is made of the poor thermal conductivity, excellent heat resistance but cheap ceramics. So that the cost is reduced to half the original ceramic LED package.
Although the structure of this package is very simple, but the low melting point of copper is difficult and ceramic compositions. To this end, the company has developed a capable lower than the melting point of copper fired, combined with strong copper ceramics. Temperature control and fixed by firing at ways to improve, and successfully developed an electrode (lead frame between the top) interval of less than 70μm precision chip backplane (Figure 16). Samples are available now begin.
Figure 16: Results of the Japanese tungsten LED package thermal analysis and test products the company has developed the ability to burn below the melting point of copper and copper bonding capability with high ceramic. Prototype LED chips 10 can be installed, good thermal conductivity, the temperature of the LED chip and the lead frame difference of about 2 ℃. In thermal analysis, the higher the temperature the closer to red.
Denki Kagaku Kogyo's "electrification AGSP floor" is also a means to improve the heat dissipation properties of the LED package. The company uses Japanese Industry (Headquarters: Nagano Okaya) developed technology, to create a copper cylinder of arbitrary shape anywhere throughout the floor. If the bottom part of the housing as the use of LED package, it is possible by means of contact with the LED chips of the pillars, the heat conduction to the heat sink. Although the cost is still to be solved, but the use of the new package is fully expected to expand in the future.
