CN103047553A - High-luminous-efficacy high-power light-emitting diode (LED) panel light - Google Patents

Abstract

The invention discloses a high-efficiency high-power LED panel light. The panel light includes a base plate, LED light bar, reflector, light guide plate, power supply, panel, the base plate is a square structure, the edge of the square structure is curved and warped, the base plate is coated with a reflective film, and the reflectivity of the reflective film is from the edge to the middle. Gradually rising, the warping surface of the edge of the square structure is coated with a high-reflectivity reflective film to form a reflector. The LED light bar is composed of LED chips integrated and packaged on an aluminum substrate. The LED light bar is installed in front of the reflector around the base plate, and the light guide plate It is made of a material doped with scattering particles whose refractive index is close to that of the LED chip. The light guide plate is installed on the bottom plate, and the edge is precisely bonded to the LED chip. The light guide plate is fixed on the bottom plate through the panel and screws. The high-efficiency and high-power LED panel lamp of the present invention has uniform light-emitting surface brightness, good heat dissipation of the lamp, and high light-emitting efficiency.

Description

A high-efficiency high-power LED panel light

technical field

The invention relates to the field of LED lighting, in particular to a high-efficiency and high-power LED panel light.

Background technique

The first commercial LED came out in 1965, using GaAsP material, its structure is similar to ordinary diodes, its luminous efficiency is very low, and it can only emit red light of a few thousandths of a lumen. With the development of semiconductor doping technology, in 1985, Nishizawa in Japan used the liquid phase epitaxy method to prepare a heterostructure AIGaAs light-emitting diode with a brightness higher than that of the previous light-emitting diode, which was later called a high-brightness light-emitting diode. Research in the 1980s mainly focused on the P-N junction and improving the internal quantum efficiency. In the early 1990s, the research on the quaternary III-V semiconductor alloy material InGaAIP material was successful. Another huge breakthrough in the early 1990s was accomplished by Nakamura of Nichia Corporation in Japan. Nakamura successfully prepared high-brightness blue and green light-emitting diodes on GaN-based materials, with a luminous intensity exceeding 1cd, followed by a single quantum well The structure obtains blue, green, and yellow InGaN-based LEDs larger than 10cd, and expands the luminescent spectrum region of the light-emitting diode from the original 650-560nm to 650-470nm.

In the 1970s, LED was mainly used for indication; in the 1980s, it was used for outdoor display; in the 1990s, it was used for outdoor TV and car indication; at the end of the last century, it was used for traffic lights; at the beginning of the 21st century, people used GaN-based blue LED as the basic light source. A single LED emits white light through phosphor conversion. White LED lighting is considered to be the most valuable new technology in the 21st century because of its advantages such as high luminous efficiency, long life, energy saving, environmental protection, fast response, high safety and reliability. The light source will replace incandescent lamps and fluorescent lamps as the leading lighting market. The successful development of white LED light source has created conditions for its future application and development in the field of general lighting. Compared with traditional light sources such as incandescent tungsten bulbs and fluorescent lamps, LED light sources are most attractive to the world for their energy-saving and environmental protection features. Compared with incandescent lamps, white LED lighting can save electricity by 80% to 90%. It can save 50% of electric energy; the life span can reach 80,000 to 100,000 hours, which is 20 to 30 times that of incandescent lamps and 10 times that of fluorescent lamps. Especially after it is used in combination with solar cells and electromagnetic induction batteries, it is an extremely Competitive green light sources are expected to become a new generation of ideal solid-state energy-saving lighting sources in the next 10 to 20 years, writing a new chapter for the history of human lighting.

According to the application range of existing products, semiconductor lighting can be divided into six categories: one is outdoor landscape lighting: guardrail lights, projection lights, LED light strips, LED special-shaped lights, digital light tubes, buried lights, lawn lights, underwater lights, etc. , the second is interior decoration lighting: wall lamps, chandeliers, recessed lights, spotlights, corner lights, flat luminous panels, grille lights, fluorescent lights, downlights, changing lights, etc., and the third is special lighting: portable lighting (flashlights, headlights ), low-illumination lights (corridor lights, house lights, court lights), reading lights, microscope lights, projection lights, camera flash lights, table lamps, street lights, etc., the fourth is safety lighting: miner's lamps, explosion-proof lights, emergency lights, safety lights etc., the fifth is special lighting: military lighting, medical non-heat radiation lighting, treatment lights, germicidal lights, special lighting for crops and flowers, special biological lights, special LED lights combined with solar photovoltaic cells, etc., sixth is general lighting : General lighting for offices, shops, hotels, homes, etc. Although LED lighting has not officially entered this field yet, with the continuous advancement of LED technology and the continuous decline of costs, it is expected that it will gradually enter the field of general lighting in the next few years. Its potential market is the largest, with hundreds of billions of yuan. The LED industry is a high-tech industry, and it is also an industry encouraged by energy-saving and emission-reduction policies. It is also environmentally friendly. Judging from the current level of semiconductor lighting technology and market demand, there is still a lot of room for development.

The requirement for semiconductor LED light sources in the field of lighting is to increase their luminous efficiency and luminous flux to the level of existing lighting sources. Due to the continuous improvement of the input power of LED chips, higher requirements are put forward for the packaging technology of power LEDs. In response to the requirements for light sources in the lighting field, the packaging of power LEDs for lighting faces the following challenges: ① Higher luminous efficiency; ② Higher single light flux; ③ Better optical characteristics (light directivity, color temperature, display chromaticity, etc.); ④ Greater input power; ⑤ Higher reliability (lower failure rate, longer life, etc.); ⑥ Lower luminous flux cost.

The design of LED panel lights mainly involves the following aspects:

Light source selection: At present, panel lights generally use packaged LED lamp bead arrays on aluminum substrates. The direct packaging technology of COB (chip on board) substrates is introduced into high-efficiency LED lighting, which can not only effectively reduce heat deposition inside the light source. To dissipate, and through various forms of series-parallel connection between chips, indirectly reduce the current density on the chip and reduce the generation of heat. Through the newly designed strip-shaped large-area metal aluminum substrate, and based on the thermal stress buffer design, the chip is directly bound to the metal substrate through the die-bonding glue, reducing the need for traditional low-power light sources to be welded through an additional layer of FR4/aluminum-based materials layer link, simplify the heat channel, and conduct heat directly to the heat sink through the metal aluminum substrate (we can also increase the area of the aluminum substrate to play the role of a part of the heat sink), and at the same time separate the circuit and the metal plate through the separation design Completely isolated, the dedicated heat conduction path and current path do not interfere with each other, effectively achieving thermoelectric separation.

Light extraction: At present, panel lights generally use LED lamp bead arrays, and then emit light into the light guide plate. How to design a good light output channel so that the light emitted by LEDs can be efficiently exported to the panel lights, the following issues need to be considered: the reflective cavity Design; lens design; joint interface design and refractive index matching of various materials in the light exit channel; minimizing unnecessary light absorption and leakage in the light exit channel. We choose the appropriate light channel material through the following selection principles: high light transmittance, well-matched refractive index, anti-UV, anti-yellowing characteristics, high temperature tolerance and good stress characteristics. Since the refractive index of the chip's active layer (i.e., the light-emitting layer) is relatively high (the refractive index of GaN material n=2.4, and the refractive index of GaP material n=3.3), if the refractive index of the material bonded to the light-emitting channel and the chip surface is the same as If the difference is large (such as n=1.5 for epoxy resin), the critical angle of total reflection on the surface of the chip will be small, and only part of the light emitted by the chip can escape through the interface and be effectively used, and a considerable part of the light will be lost due to total reflection. Trapped inside the chip, resulting in low light extraction efficiency, which directly affects the luminous efficiency of the LED. In order to improve the light extraction efficiency, when selecting the material to be bonded to the chip surface, it must be considered that its refractive index should match that of the chip surface material as much as possible. Flexible silica gel with a high refractive index is used as the material bonded to the surface of the chip, which can not only improve the light extraction efficiency, but also provide good stress protection for the chip and bonding wires. When light passes from one medium to another, part of the incident light is refracted and the other part is reflected. If light is directed from an optically dense medium (refractive index n1) to an optically sparse medium (refractive index n2), when the incident angle (i1) is greater than the critical angle of total reflection (ic), the refracted light disappears and all the light is reflected. The refractive index of the active layer (that is, the light-emitting layer) is relatively high (GaNn=2.4, GaPn=3.3), if the refractive index of the material that is bonded to the light channel and the chip surface is quite different from it (such as n=1.5 for epoxy resin) , it will lead to a small critical angle of total reflection on the surface of the chip, only a part of the light emitted by the chip can be effectively used by escaping through the interface, and a considerable part of the light is trapped inside the chip due to total reflection, resulting in low light extraction efficiency. Directly affect the luminous efficiency of LED. In order to improve the light extraction efficiency, when selecting the material to be bonded to the chip surface, it must be considered that its refractive index should match that of the chip surface material as much as possible. Using flexible silica gel with a high refractive index as the bonding material on the surface of the chip can not only improve the light extraction efficiency, but also provide good stress protection for the chip and the bonding wire.

Light guide plate design: Among the components of the side-type backlight module, the performance of the light guide plate plays an important role in the brightness uniformity of the backlight source and the performance of the display. The design of the light guide plate is the most important and the most technical work in the design of the side-type backlight. With the development of display technology, there are higher requirements for the performance of the light guide plate. The light guide plate has gone through several generations of development. According to the different processes, it can generally be divided into several types of light guide plates, such as screen printing, direct injection molding and polymer molding.

Heat dissipation structure design: the heat generated by the LED will accumulate inside the LED, the junction temperature of the chip will increase severely, the luminous efficiency will drop sharply, and the reliability (such as lifespan, color shift, etc.) will deteriorate. At the same time, high temperature and high heat will cause mechanical stress inside the LED packaging structure, which may cause a series of reliability problems. Therefore, solving the heat dissipation problem is the most important thing to improve the reliability of LEDs. The heating of the LED itself increases the junction temperature of the chip, resulting in a decrease in the luminous efficiency of the chip. Power LEDs must have a good heat dissipation structure, so that the heat inside the LED can be exported and dissipated as quickly as possible, so as to reduce the junction temperature of the chip and improve its luminous efficiency.

Contents of the invention

Aiming at the low luminous efficiency and poor heat dissipation of traditional LED panel lights, a high-efficiency and high-power LED panel light is designed. The present invention is realized through the following technical means:

A high-efficiency and high-power LED panel light, including a base plate, an LED light strip, a reflector, a light guide plate, a power supply, and a panel. In the light panel, part of the light is directly emitted through the light guide plate, and the other part of the light is emitted after being reflected by the bottom plate.

In the above high-efficiency high-power LED panel light, the bottom plate is a square structure, the edges of the square structure are curved and warped, and the bottom plate is made of aluminum, copper or aluminum-copper alloy.

In the above-mentioned high-efficiency high-power LED panel light, the base plate is coated with a reflective film, and the reflectance of the reflective film gradually increases from the edge to the middle. Higher, so the reflected light intensity is high in the middle and low in the edge, because the light intensity directly emitted by the LED is low in the edge and high in the middle, by setting the reflectivity curve reasonably, the light output of the panel light can be made uniform.

In the above-mentioned high-efficiency high-power LED panel light, the curved surface of the edge of the square structure is coated with a high-reflectivity reflective film to form a reflector.

In the above high-efficiency high-power LED panel light, the LED light bar is composed of LED chips integrated and packaged on an aluminum substrate.

In the above-mentioned high-efficiency high-power LED panel light, the LED light bar is installed in front of the reflectors around the bottom plate.

In the above-mentioned high-efficiency high-power LED panel light, the light guide plate is made of a material doped with scattering particles whose refractive index is close to the refractive index of the LED chip, the light guide plate is installed on the bottom plate, and the edge is precisely bonded to the LED chip. The light guide plate and the light emitting surface of the LED light source are filled and bonded with a flexible silicone material. The refractive index of the flexible silicone material is close to that of the light guide plate and the LED light source, so as to ensure that the light emitted by the LED can enter the light guide plate to the maximum extent.

In the above-mentioned high-efficiency high-power LED panel light, the light guide plate is fixed on the bottom plate through the panel and screws.

Description of drawings

Fig. 1 is a structural schematic diagram of a high-efficiency high-power LED panel light of the present invention.

Fig. 2 is a schematic diagram of installation of an LED light bar of a high-efficiency high-power LED panel light of the present invention.

Fig. 3 is a schematic diagram of the packaging structure of a high-efficiency high-power LED panel lamp and an LED chip of the present invention

Fig. 4 is a simulation diagram of light intensity distribution of a high-efficiency high-power LED panel light of the present invention.

Implementation

Specific embodiment one

As shown in Figure 1, it is an overall structural diagram of a high-efficiency high-power LED panel light of the present invention, which comprises a base plate 1, a light guide plate 2, a panel 3, a reflector 4, an LED light bar 5, a power supply 6, The base plate 1 of the panel light is formed by die-casting the aluminum base plate. There is an arc warp around the edge of the base plate. Use a vacuum ion coating machine to coat a layer of mirror reflection film on the inner surface of the warping to form a reflector. Use a vacuum ion coating machine to coat the base plate. A layer of reflective film is coated on the top, and the reflectivity of the reflective film gradually increases from the edge to the middle. The LED light bar 5 is installed on the edge around the bottom plate 1, and the light guide plate 2 doped with scattering particles whose refractive index is close to the LED chip is installed. On the base plate, the edges around the light guide plate are closely bonded to the LED chip, and the LED chip and the light guide plate are filled and bonded with a flexible silicone material whose refractive index is close to that of the light guide plate. When the light emitted by the LED light strip 5 passes through the After being focused by the device 4, it is injected into the light guide plate, a part of the light is directly emitted, and the other part of the light is emitted after being reflected by the bottom plate. Since the reflectivity of the reflective film coated on the bottom plate is low at the edge and high in the middle, by setting the reflectivity curve reasonably, it can be made The brightness of the light emitting surface of the panel light tends to be uniform.

As shown in Figure 2, it is a schematic diagram of the installation of the LED light bar of the present invention. The LED chip 11 is packaged on the aluminum substrate 12, and the heat generated in the LED chip 11 is conducted to the bottom plate through the aluminum substrate, because the bottom plate and the reflector are integrated. , increasing the overall cooling area.

As shown in FIG. 3 , it is a schematic diagram of the LED chip packaging structure of the present invention. The LED chip 21 is bonded to the groove on the long aluminum substrate 22 with a die-bonding adhesive, and the LED chips are connected in series using a bonding machine. Phosphor powder packaging is poured into the groove, and the chips are driven in series with a constant current.

In this embodiment, a rectangular aluminum alloy sheet of 800*800*5mm is used to press the base plate of the LED panel light, and the arc-shaped warping arc is 30 degrees, and a total of 480 LED chips are integrated and packaged in four long strips. Light bars are formed on the aluminum substrate, and the LED chips in each light bar are driven in series with a constant current. The four light strips are divided into four circuits and driven in parallel. When the lamp is lit, the surface brightness of the light guide plate is uniform, the light is soft, and no obvious bright and dark areas can be seen. 100 hours after the lamp is lit, the surface temperature of the lamp is lower than 50 degrees Celsius.

Claims (9)

1. a high-efficient large power panel LED lamp comprises base plate, LED lamp bar, and reflector, LGP, power supply, panel is characterized in that: LED lamp bar is positioned at around the base plate, and the light that light source sends is injected in the LGP after compiling through reflector.

2. a kind of high-efficient large power panel light according to claim 1 is characterized in that described bottom edge has the arc warpage, and arc warpage inner surface is coated with reflectance coating.

3. a kind of high-efficient large power panel light according to claim 1 is characterized in that described base plate uses metal material, and described metal material can be aluminium, copper and aluminium copper.

4. a kind of high-efficient large power panel light according to claim 1 is characterized in that described backplate surface has been coated with one deck reflectance coating, and reflectance coating is raise to the middle part by the edge gradually to the reflectivity of emergent light.

5. a kind of high-efficient large power panel light according to claim 1 is characterized in that the accurate applying of described LGP and led light source exiting surface.

6. a kind of high-efficient large power panel light according to claim 1 is characterized in that described light guide panel material refractive index and led light source refractive index are close.

7. a kind of high-efficient large power panel light according to claim 1 is characterized in that adopting the flexible silicon glue material to fill between described LGP and the led light source exiting surface bonding, and the refractive index of flexible silicon glue material and LGP and led light source refractive index are close.

8. a kind of high-efficient large power panel light according to claim 1, what it is characterized in that described led chip adopts is that integration packaging is on aluminium base.

9. a kind of high-efficient large power panel light according to claim 1 is characterized in that described led chip adopts the mode of series connection to connect, and adopts mode in parallel to connect between the lamp bar.

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