CN102661516A

CN102661516A - Novel high-power light emitting diode (LED) light source structure based on non-metal-based printed circuit board

Info

Publication number: CN102661516A
Application number: CN2012101470857A
Authority: CN
Inventors: 张建新; 牛萍娟; 杨庆新; 李红月; 孙连根
Original assignee: Tianjin Polytechnic University
Current assignee: Tianjin Polytechnic University
Priority date: 2012-05-14
Filing date: 2012-05-14
Publication date: 2012-09-12

Abstract

The invention discloses a novel high-power light emitting diode (LED) light source structure based on a non-metal-based printed circuit board (PCB). The novel high-power LED light source structure mainly comprises high-power LEDs, non-metal-based PCBs, a radiator, and a corresponding insulating spacer or gasket which is added according to the needs of electrical insulation and fastening degree control, wherein LEDs have a thermoelectrically separated pin type packaging structure, the pins can be bent toward the direction of a lens or a base, provide electrical connection and provide high fastening force; the non-metal-based PCBs are common hard single-sided copper-clad plates and are provided with LED assembling through holes which have the same number as that of the LEDs, and two sides of each assembling through hole are uniformly provided with circuits and pads; and therefore, the welded LEDs can give out light outwards through the assembling through holes, and the assembling through holes have the functions of clamping the LEDs at fixed points and can provide high fastening force. The LED bases with the novel structure can be directly contacted with the radiator, so that the radiating thermal resistance is obviously reduced.

Description

High-power LED light source new construction based on the non-metal base circuit board

Technical field

The present invention relates to the led light source new construction, relate in particular to based on the non-metal base circuit board realize good being electrically connected, the high-power LED light source new construction of physical carrier and radiating effect, can be widely used in the LED field of semiconductor illumination.

Background technology

LED (Light Emitting Diode) light emitting semiconductor device possess conventional light source incomparable many performance advantages, be a new generation's " green illumination " light source that meets energy-conserving and environment-protective, its application is constantly expanded.At present, thereby open huge general illumination market for the realization led light source substitutes conventional lamp on a large scale, LED need significantly improve its input electric power to reach higher luminosity.Yet improving constantly of input electric power, great power LED (will supervene up to 100W/cm by>=1W) chip area ²Above heat flow density is the several times of conventional cpu chip quantity of heat production.If concentrating on the chip, heat can not in time shed; Then can cause chip to heat up rapidly, can not only cause the non-uniform Distribution of thermal stress, the speed-up chip deterioration; Seriously shorten device lifetime, can also significantly reduce luminous intensity and fluorescent material and swash advantage service behaviours such as penetrating efficient.Therefore, effectively solve heat dissipation problem, become the prerequisite that the illuminative high-power LED light source is realized extensive commercial application to reduce LED junction temperature (chip active area temperature) to greatest extent.

In the led light source structure, common non-metal base PCB (Printed Circuit Board, circuit board) thermal conductivity is very poor, and comprehensive thermal conductivity factor is merely 0.3W/ (mK), generally can only very little as caloric value, almost not have the low-power LED lamp plate of a heat radiation difficult problem.In order to satisfy the radiating requirements of high-power LED light source, developed in the industry a kind of have high thermal conductivity can the metal-base circuit plate (Metal Core PCB, MCPCB).Because it adopts the very thin dielectric material of one deck, it is bonding that the copper foil layer that will be used to make circuitous pattern and thermal conductivity good metal substrate (being generally aluminium base) carry out, comprehensively the highest 3W/ (mK) that is promoted to of thermal conductivity factor.With the lamp plate of MCPCB as LED; Can bear be electrically connected with mechanical bearing function in; Realize the decline of thermal resistance value on the thermal dissipating path; Thereby improve the heat-sinking capability of high-power LED light source structure, so the MCPCB lamp plate becomes the important component of present stage high-power LED light source production and assembling.

At present, the traditional approach based on MCPCB assembling high-power LED light source structure is that after copper foil circuit one face down bonding of MCPCB connect the LED pin, the metal substrate with opposite side was fastened on the radiator with screw again.In order to reduce interface resistance, on two contact interfaces between LED base, MCPCB, the radiator, also can be pre-charged with heat-conducting silicone grease usually.Yet often there is following problem in this assembly structure: the heat that (1) LED produces must be dispersed in the surrounding environment through encapsulation base plate → heat-conducting silicone grease filling interface 1 → MCPCB → this approach of heat-conducting silicone grease filling interface 2 → radiator; Its heat flow path is longer, and separation structure thermal resistance and interface resistance are more; (2) only rely on the faint fastening force that produces after the welding of LED pin, be difficult to guarantee to reduce to greatest extent the thickness of heat-conducting silicone grease layer under the LED base, cause the applying at interface 1 not tight, even have obvious gaps, interface resistance is higher; (3) the MCPCB area is bigger, must smear a large amount of heat-conducting silicone greases when assembling with radiator, when screw is fastening, also need bubble and unnecessary silicone grease be discharged in the interface, because the price of heat-conducting silicone grease is higher, consumption is big, and assembly cost is higher; And the silicone grease flowability is relatively poor, in the far and near different zone apart from screw, the situation that bubble is residual and silicone grease is in uneven thickness very easily occurs and takes place, and brings the thermal resistance at interface 2 bigger, the relatively poor consequence of regional uniformity thereupon.

Same MCPCB itself also comes with some shortcomings: the inner dielectric layer of (1) MCPCB is polymer composite, and its capacity of heat transmission is low excessively, becomes through MCPCB and carries out heat conducting bottleneck; (2) temperature tolerance of dielectric layer material is relatively poor, in manufacture process, must not surpass 250 ℃～300 ℃, therefore when crossing the tin stove, must adjust the temperature control parameter of welding procedure in advance;

(3) metal material that the manufacturing of MCPCB must labor is as substrate, and complex process, makes the lamp plate cost high, has limited the potentiality of its market development, has influenced the popularity of high-power LED light source to domestic consumer.

Compare with MCPCB, common non-metal base PCB lighter weight, manufacturing process is ripe, and low production cost has good heat-resisting quantity, is applicable to the requirement of different welding procedures.Yet; Because the thermal conductivity of non-metal base plate is very poor; Be only limited to caloric value very little, almost do not have the making of low-power LED lamp plate of a heat radiation difficult problem, therefore, must improve relevant structural design in order to be applied in the high-power LED light source; Thereby realize being electrically connected with mechanical bearing function in, significantly promote the heat-sinking capability of light-source system.

Summary of the invention

The present invention is directed to the problems that center on the application of MCPCB in the high-power LED light source traditional structure and exist; Aim to provide out a kind of high-power LED light source new construction based on non-metal base PCB; Change the traditional design that non-metal base PCB can only be used for the low-power LED lamp plate, make its can realize being electrically connected with mechanical bearing function in, significantly promote the heat-sinking capability of light-source system; Reduce and control the junction temperature of chip of great power LED; Guarantee its each item service behaviour, and can reduce manufacturing and installation cost, thereby meet the demand of mass industrialized production.

In order to achieve the above object; The technical scheme that the present invention adopts is: based on the high-power LED light source new construction of non-metal base PCB; Mainly comprise great power LED, non-metal base PCB, radiator; And, set up corresponding insulation pad or packing ring according to the needs of electric insulation and fastening extent control.Wherein, great power LED adopts the thermoelectric pinned encapsulating structure that separates, and promptly encapsulation base plate only provides thermal dissipating path, and has good electricity isolation between pin.The LED pin can be crooked to lens direction or base direction, when being responsible for being electrically connected, bigger fastening force can also be provided.Non-metal base PCB is common hard single-side coated copper plate, and the non-metal base plate of solder mask on the circuit or another side surface painted white is beneficial to reflective.Non-metal base PCB is provided with the assembling through hole of LED; Its quantity is consistent with LED; And the both sides of each assembling through hole are evenly equipped with circuit and LED pin pad; Make the LED after being welded can be outwards luminous, and the assembling through hole can also provide fastening force largely when LED being played fixed point screens effect through the assembling through hole.The somewhat larger in diameter of through hole is in the diameter of LED plastic stent.

Radiator is thermal conductivity good metal or embedded heat pipe radiator, and increases its efficiently radiates heat area as far as possible; Insulation spacer can be FR4 epoxy resin, polyimides, polythioamine, BT resin, polyester, polyflon or the like material; The plain washer with strong ability of anti-deformation of the preferred non-metallic material of packing ring, insulation spacer all should be slightly less than the LED base with the thickness of packing ring and contact the distance between back PCB and the radiator installed surface with radiator.

Beneficial effect of the present invention is: meter is sent out through the structure of improving non-metal base PCB in (1); And assemble out the high-power LED light source new construction; The LED encapsulation base plate is directly contacted with the radiator installed surface; Self thermal resistance of PCB and the thermal resistance of heat-conducting silicone grease filling interface 2 have been omitted; Not only shorten heat flow path greatly and significantly reduced the junction temperature of chip of LED, and also need not to smear heat-conducting silicone grease between PCB and radiator installed surface, thereby avoided discharge difficulty, the interface uniformity of bubble and unnecessary silicone grease poor, silicone grease expends problems such as cost height; (2) this non-metal base PCB is the hard single-side coated copper plate, and its rigidity is stronger, can suitably improve the fastening force that is applied on LED package casing or the pin after being installed by screw, thereby guarantee the applying quality at interface 1, reduces interface resistance; (3) compare with MCPCB, common non-metal base PCB lighter weight, manufacturing process is ripe, and low production cost has good heat-resisting quantity, is applicable to the requirement of different welding procedures, meets the demand of mass industrialized production, is with a wide range of applications.

Description of drawings

Fig. 1 is the explosive view of embodiment 1;

Fig. 2 is the sketch map of the LED1 that pin 113 makes progress among Fig. 1;

Fig. 3 is the tow sides sketch map of non-metal base PCB2 among Fig. 1;

Fig. 4 is the packing ring 3 among Fig. 1;

Fig. 5 is a radiator 4 among Fig. 1;

Fig. 6 is the explosive view of embodiment 2;

Fig. 7 is the sketch map of the downward LED5 of pin 253 among Fig. 6;

Fig. 8 is the tow sides sketch map of non-metal base PCB6 among Fig. 6;

Fig. 9 is the insulation spacer 7 among Fig. 6.

The specific embodiment

Embodiment 1

As it is shown in Figure 1 to explode, and a kind of high-power LED light source new construction based on the non-metal base circuit board comprises LED1, non-metal base PCB2, packing ring 3, and radiator 4.Wherein, the pin 113 of LED1 makes progress, and PCB2 is provided with LED installation through holes 121, and the somewhat larger in diameter of through hole 121 is in the diameter of LED1 plastic stent 112.PCB2 covers in the front copper 123, and said front is an exiting surface.The plain washer with strong ability of anti-deformation of packing ring 3 preferred non-metallic materials.Through hole 121 on each PCB2 all embeds a LEDs 1 accordingly, and the pin 113 of LED1 is welded on the Copper Foil 123 of corresponding through hole both sides, forms to be electrically connected.The base 114 of LED1 can directly contact with radiator top 141 through through hole.Scribble heat-conducting silicone grease on the described base 114, the heat of LED1 can directly be passed on the radiator top 141 through heat-conducting silicone grease.Packing ring 3 is installed between the screw hole 142 of the screw hole 122 of PCB2 and radiator then, and said packing ring has the effect of location, fastening and buffering.With the screw hole 122 of screw through PCB2, the screw hole 131 of packing ring carries out fastening with the screw hole 142 of radiator at last.

Embodiment 2

As it is shown in Figure 6 to explode, and a kind of high-power LED light source new construction based on the non-metal base circuit board comprises LED5, non-metal base PCB6, insulation spacer 7, and radiator 4.Wherein the pin 253 of LED5 is downward, and PCB6 is provided with LED installation through holes 261, and the somewhat larger in diameter of through hole 261 is in the diameter of LED5 plastic stent 252.The PCB6 reverse side covers copper 264, and said reverse side is non-exiting surface.Through hole 261 on each PCB6 all embeds a LEDs 5 accordingly, and the pin 253 of LED5 is positioned at the reverse side of PCB6, is welded on the Copper Foil 264 of corresponding through hole both sides, forms to be electrically connected.Insulation spacer 7 is installed between PCB6 and the radiator top 141, and said insulation spacer 7 mainly plays the pin insulation and fastening effect is installed.Said insulation spacer 7 is provided with through hole 271, and the base 254 of LED5 can directly be connected with radiator top 141 through through hole 271.Scribble heat-conducting silicone grease on the said base 254, the heat of LED5 can be directly delivered on the radiator top 141 through heat-conducting silicone grease like this.Carry out fastening with the screw hole 262 of screw through PCB6 and insulation spacer 7 screw holes 272 with radiator screw hole 142 at last.

Present embodiment also because PCB6 is that reverse side covers copper, makes its solder joint be positioned at the back side except possessing aforementioned advantages, and exiting surface is then more neat and artistic.

Although relate to a kind of high-power LED light source new construction and carried out special description disclosed based on the non-metal base circuit board with reference to embodiment; And the embodiment of above description is illustrative rather than restrictive; Under the situation that does not break away from the spirit and scope of the present invention, all variations and modification are all within scope of the present invention.

Claims

1. high-power LED light source new construction based on non-metal base PCB; Mainly comprise great power LED, non-metal base PCB, radiator; And, set up corresponding insulation pad or packing ring according to the needs of electric insulation and fastening extent control, it is characterized in that: all be provided with installation through holes on described non-metal base PCB and the insulation spacer; Make described LED outwards luminous through the PCB installation through holes; And LED can directly be connected with radiator through installation through holes, has shortened heat flow path greatly and significantly reduces the junction temperature of chip of LED, raising radiating efficiency; In addition, only on the base of every LED, scribble heat-conducting silicone grease, then need not to smear heat-conducting silicone grease between PCB and radiator installed surface, thereby avoided that the discharge difficulty of bubble and unnecessary silicone grease, interface uniformity are poor, silicone grease expends problems such as cost height.

2. a kind of high-power LED light source new construction according to claim 1 based on non-metal base PCB; It is characterized in that: the pin of said LED can be crooked to lens direction or base direction; And be welded on the PCB Copper Foil of corresponding through hole both sides, form electrical connection.

3. according to right 1 described a kind of high-power LED light source new construction based on non-metal base PCB, it is characterized in that: said PCB is common non-metal base single-side coated copper plate.

4. according to right 1 described a kind of high-power LED light source new construction based on non-metal base PCB, it is characterized in that: described insulation spacer or packing ring play the effect of insulation, location, fastening and buffering between PCB and radiator.