CN100502065C - High-efficiency fluorescent conversion LED light source and backlight module - Google Patents

Abstract

A high efficient fluorescence conversion LED light source and backlight module comprise an LED arranged in a reflecting cup or the bottom of a collimating lens, and a fluorescent powder layer with predetermined thickness which is arranged on the top and is scattered with or coated with fluorescent powders and in particular comprises a first cut-off filter which is arranged between the fluorescent powder layer and the top of the reflecting cup or the collimating lens. Photons from the predetermined wavelength range of the LED penetrate the cut-off filter with an angle of incidence smaller than the predetermined value, while the backward fluorescence photons are reflected by the cut-off filter, thereby improving the fluorescence extraction efficiency. In addition, a second cut-off filter which has the opposite wave property is arranged above the fluorescent powder layer in order that the fluorescence photons can penetrate the second cut-off filter; a chamber structure consisting of two filters has multiple reflections on the incentive photons which are not absorbed by fluorescent powders to fully improve the absorption rate of the incentive photons. With the invention, the product has prominent fluorescence conversion effect and is simple in structure and technique, and convenient in realization of low cost.

Description

Translated fromChinese

高效荧光转换的LED光源及背光模块High-efficiency fluorescent conversion LED light source and backlight module

技术领域 本发明涉及LED光源及背光模块实现高效荧光转换的结构。Technical field The present invention relates to the structure of LED light source and backlight module to realize high-efficiency fluorescent conversion.

背景技术 传统半导体发光二极管(Light Emitting Diode，LED)以GaAsP和GaAlAs材料为主，它的发展始于二十世纪六十年代初，波长覆盖了从可见光波段的绿色和红色一直到近红外波段。但由于输出功率和亮度低，传统LED的应用主要限制于信号指示灯、电视遥控器以及低速短距离光纤通讯等方面。Background Art Traditional semiconductor light-emitting diodes (Light Emitting Diode, LED) are mainly made of GaAsP and GaAlAs materials. Its development began in the early 1960s, and its wavelength covers green and red from the visible light band to the near-infrared band. However, due to low output power and brightness, the application of traditional LEDs is mainly limited to signal indicators, TV remote controls, and low-speed short-distance optical fiber communications.

自二十世纪九十年代初以来，以InGaAlP和InGaN为主的新一代半导体光电子材料迅速发展起来，各种高功率高亮度的红、黄、蓝、绿、紫外以及白光等LED光源纷纷涌现，层出不穷，在各种显示和照明领域得到了越来越广泛的应用。Since the early 1990s, a new generation of semiconductor optoelectronic materials based on InGaAlP and InGaN has developed rapidly, and various high-power and high-brightness red, yellow, blue, green, ultraviolet and white LED light sources have emerged. Emerging in endlessly, it has been more and more widely used in various display and lighting fields.

其中，白光LED光源的主要技术方案有RGB混光和荧光转换两种。荧光转换方案是利用LED芯片发射较短波长的光来激发转换荧光粉发出白光。例如，日本日亚公司(Nichia)的白光LED专利，公开了利用470纳米蓝光LED芯片来激发黄色YAG荧光粉发出白光的技术方案。该方案结构简单、制造成本低、产品具有很强的实用性。Among them, the main technical solutions of white LED light source are RGB mixed light and fluorescent conversion. The fluorescent conversion scheme is to use the LED chip to emit light with a shorter wavelength to excite the conversion phosphor to emit white light. For example, the white light LED patent of Japan's Nichia Corporation (Nichia) discloses a technical solution for using a 470nm blue LED chip to excite yellow YAG phosphors to emit white light. The scheme is simple in structure, low in manufacturing cost, and the product has strong practicability.

白光LED光源的发展目标是以高流明效率和低成本优势逐渐取代白炽灯和荧光灯等传统光源。到目前为止，白光LED光源的主要技术指标---流明效率，据报道在数十毫安工作电流下已经超过100流明/瓦，而在数百毫安工作电流下已经达到80流明/瓦，都比白炽灯的15流明/瓦和荧光灯的70流明/瓦要高。但目前该白光LED光源的制造成本还相对较高。The development goal of white LED light sources is to gradually replace traditional light sources such as incandescent lamps and fluorescent lamps with the advantages of high lumen efficiency and low cost. So far, the main technical index of white LED light source --- lumen efficiency, it is reported that it has exceeded 100 lumens/watt under the working current of tens of milliamperes, and has reached 80 lumens per watt under the working current of hundreds of milliamperes. Both are higher than 15 lumens/watt for incandescent lamps and 70 lumens/watt for fluorescent lamps. However, the manufacturing cost of the white LED light source is relatively high at present.

随着芯片发光效率、荧光粉吸收和转换效率以及封装效率的提高，白光LED光源的流明效率还有较大提高空间，这对于降低白光LED光源成本，节能降耗都具有重要意义。With the improvement of chip luminous efficiency, phosphor absorption and conversion efficiency, and packaging efficiency, there is still room for improvement in the lumen efficiency of white LED light sources, which is of great significance for reducing the cost of white light LED light sources and saving energy.

图1示意了现有多种荧光转换LED光源结构，见于2005年日本应用物理期刊(Journalof Applied Physics，Japan)第44卷第21期第649～651页。一般来说，荧光转换LED光源至少包括LED、荧光粉及用来改变光子方向的反射杯，所述LED置于反射杯的底部开口。在图1a的方案中，所述荧光粉3被直接涂覆于LED芯片1之上，胶体4覆盖荧光粉3并填充反射杯2的剩余空间，从而荧光粉3在LED芯片1发射出的光子激励下，发出特定波长的光子并经反射杯2收集定向射出。为避免该方案中荧光粉发光效率和寿命受LED芯片发热产生的不利影响，图1b的方案将荧光粉3改为均匀散布于胶体4中，可以既提高荧光转换效率，延长荧光粉寿命，又提高光源输出的均匀性。为了进一步提高荧光转换效率，图1c的方案对光源结构又作了改进：在反射杯2正对LED芯片1的开口处设置一荧光粉层，该荧光粉层与LED芯片之间的空间填充以具有折射系数匹配的胶体，图1d的方案中又将所述反射杯的杯壁由镜面反射特性改为漫反射特性，对荧光转换效率又有所提高。Figure 1 schematically shows the structure of various existing fluorescent conversion LED light sources, which can be found on pages 649-651 of Volume 44,Issue 21 of the Journal of Applied Physics, Japan in 2005. Generally speaking, the fluorescent conversion LED light source at least includes LED, fluorescent powder and a reflective cup used to change the direction of photons, and the LED is placed in the bottom opening of the reflective cup. In the scheme of FIG. 1a, thephosphor powder 3 is directly coated on theLED chip 1, and thecolloid 4 covers thephosphor powder 3 and fills the remaining space of thereflective cup 2, so that the photons emitted by thephosphor powder 3 on theLED chip 1 Under excitation, photons of a specific wavelength are emitted and collected by thereflective cup 2 for directional emission. In order to avoid the adverse effect of phosphor luminous efficiency and lifespan caused by the heating of the LED chip in this scheme, the scheme in Figure 1b changes thephosphor powder 3 to be evenly dispersed in thecolloid 4, which can not only improve the fluorescence conversion efficiency, prolong the life of the phosphor powder, but also Improves the uniformity of light output. In order to further improve the fluorescent conversion efficiency, the scheme in Fig. 1c has improved the structure of the light source: a phosphor layer is arranged at the opening of thereflective cup 2 facing theLED chip 1, and the space between the phosphor layer and the LED chip is filled with Colloid with matching refractive index, in the solution of Fig. 1d, the cup wall of the reflective cup is changed from specular reflection to diffuse reflection, which improves the fluorescence conversion efficiency.

此外，SPIE(International Society for Optical Engineering)国际光学工程学会关于第5次固态照明国际会议的学报里(Proceedings of SPIE 5491，第45-50页)，也提出了一种性能得到提高的荧光转换白光LED光源结构，如图2所示：与图1d相比，该方案采用透射杯2’来替换反射杯2，还在支撑LED芯片1和透射杯2’的基底的表面镀全反射膜5’；背向荧光光子的萃取(Extracting)效率和整个荧光转换效率又进一步得到提高。In addition, in the journal of SPIE (International Society for Optical Engineering) on the 5th International Conference on Solid-State Lighting (Proceedings of SPIE 5491, pages 45-50), a fluorescent conversion white light with improved performance is also proposed. LED light source structure, as shown in Figure 2: Compared with Figure 1d, this solution uses a transmissive cup 2' to replace thereflective cup 2, and also coats the surface of the substrate supporting theLED chip 1 and the transmissive cup 2' with a total reflection film 5' ; The extraction (Extracting) efficiency of back-to-fluorescent photons and the entire fluorescence conversion efficiency are further improved.

即使这样，现有荧光转换的LED光源的不足之处在于，受激励光子的吸收效率和荧光萃取(Extracting)效率所影响的荧光转换效率仍有进一步被提高的空间。尤其图2所示的方案工艺实现上较为复杂。另外，对于单色荧光转换的LED光源，不仅需要较高的荧光转换效率，对于某些应用来说还需要输出纯净的荧光，这也是现有技术存在的不足。Even so, the disadvantage of the existing LED light source for fluorescence conversion is that the fluorescence conversion efficiency affected by the absorption efficiency of excitation photons and the extraction efficiency of fluorescence still has room for further improvement. In particular, the solution shown in FIG. 2 is relatively complex in terms of process implementation. In addition, for monochromatic fluorescent conversion LED light sources, not only high fluorescent conversion efficiency is required, but also pure fluorescent output is required for some applications, which is also a deficiency in the prior art.

发明内容 本发明要解决的技术问题是针对上述现有技术的不足，而提出一种荧光转换LED光源及背光模块，结构及工艺简单，可以高效率并低成本地实现荧光转换。Summary of the Invention The technical problem to be solved by the present invention is to address the shortcomings of the above-mentioned prior art, and propose a fluorescent conversion LED light source and backlight module, which has a simple structure and process, and can realize fluorescent conversion with high efficiency and low cost.

为解决上述技术问题，本发明的基本构思为，使用一块介于LED和荧光粉之间的光学截止滤波片，利用该光学截止滤波片对入射光子波长和角度的穿透要求既与反射杯一起提高对LED发射光子的利用率，还在采用多色荧光粉以获得纯净白光输出的同时，利用该光学截止滤波片对背向荧光的良好反射性能，从而可以大大提高荧光萃取效率，使得整体的荧光转换效率得到提高，同时产品的结构和工艺简单化。特别是当利用上下两块光学截止滤波片构成特殊腔结构，并把荧光粉层置于其中时，能用该腔结构来约束未被荧光粉吸收的激发光子，使之在腔中来回反射的行进途中有更多的几率被荧光粉吸收，从而进一步提高荧光粉对激励光子的吸收率；还便于在采用单一荧光粉时获得纯净的单色光输出。In order to solve the above-mentioned technical problems, the basic idea of the present invention is to use an optical cut-off filter between the LED and the phosphor, and use the optical cut-off filter to meet the requirements of the penetration of the incident photon wavelength and angle together with the reflective cup To improve the utilization rate of photons emitted by LED, while using multi-color phosphors to obtain pure white light output, at the same time, the optical cut-off filter is used to reflect the back fluorescence, so that the fluorescence extraction efficiency can be greatly improved, so that the overall The fluorescence conversion efficiency is improved, and the structure and process of the product are simplified at the same time. Especially when the upper and lower optical cut-off filters are used to form a special cavity structure, and the phosphor layer is placed in it, the cavity structure can be used to confine the excitation photons that are not absorbed by the phosphor, so that they can be reflected back and forth in the cavity. There are more chances to be absorbed by the phosphor during the process, thereby further improving the absorption rate of the phosphor to the excitation photon; it is also convenient to obtain pure monochromatic light output when a single phosphor is used.

作为实现本发明构思的技术方案是，提供一种高效荧光转换的LED光源，包括至少一个LED，设置在一个反射杯或准直透镜的底部；在该反射杯或准直透镜的顶部设置有一预定厚度的荧光粉层，均匀散布或涂覆着荧光粉；尤其是，还包括第一截止滤波片，介于所述荧光粉层和所述反射杯或准直透镜顶部之间，从而该反射杯或准直透镜内预定波长范围的光以小于预定值的入射角穿透该截止滤波片；当所述荧光粉为下转换荧光粉时，该第一截止滤波片为短波通截止滤波片；反之，为长波通截止滤波片。As a technical solution to realize the concept of the present invention, a LED light source for high-efficiency fluorescent conversion is provided, including at least one LED, which is arranged on the bottom of a reflective cup or collimating lens; thick phosphor layer uniformly dispersed or coated with phosphor; in particular, a first cut-off filter is included between said phosphor layer and said reflective cup or top of collimating lens so that the reflective cup Or light in a predetermined wavelength range in the collimator lens penetrates the cut-off filter at an incident angle smaller than a predetermined value; when the phosphor is a down-conversion phosphor, the first cut-off filter is a short-pass cut-off filter; otherwise , is a long-wave pass cut-off filter.

这样，可以以简单的工艺和结构来提高激励光子的吸收效率和荧光萃取效率。In this way, the absorption efficiency of excitation photons and the extraction efficiency of fluorescence can be improved with a simple process and structure.

上述方案中，所述高效荧光转换的LED光源还包括与所述第一截止滤波片波通特性相反的第二截止滤波片，设置在所述荧光粉层的上面，从而所述荧光粉激发的光子以小于第二预定值的入射角穿透该第二截止滤波片。In the above solution, the LED light source for high-efficiency fluorescent conversion further includes a second cut-off filter with the opposite wave-pass characteristics to the first cut-off filter, which is arranged on the phosphor layer, so that the phosphor-excited Photons penetrate the second cut-off filter at an incident angle less than a second predetermined value.

上述方案中，所述第一截止滤波片和第二截止滤波片的波通转折点大致一致，从而所述荧光粉层中未被荧光粉吸收的所述预定波长范围的光被所述第二截止滤波片反射回所述荧光粉层。In the above scheme, the wave pass turning points of the first cut-off filter and the second cut-off filter are roughly the same, so that the light in the predetermined wavelength range not absorbed by the phosphor in the phosphor layer is cut off by the second cut-off filter. The filter reflects back to the phosphor layer.

这样，可以进一步激励光子的吸收效率和荧光萃取效率，并便于产生纯净的光输出。In this way, the photon absorption efficiency and fluorescence extraction efficiency can be further stimulated, and a pure light output can be facilitated.

作为实现本发明构思的技术方案还是，提供一种高效荧光转换的背光模块，包括底盒，该底盒底部的散热基座，以及分布在所述散热基座上的若干LED及若干底部包围一LED的反射杯或准直透镜；所述底盒的顶部开口被一预定厚度的荧光粉层所封闭，该荧光粉层散布或涂覆着荧光粉；还包括位于所述荧光粉层之上的光扩散片以及位于该光扩散片之上的液晶显示屏；尤其是，还包括第一截止滤波片，介于各所述反射杯或准直透镜顶部和所述荧光粉层之间，从而所述底盒内预定波长范围的光以小于预定值的入射角穿透该截止滤波片；当所述荧光粉为下转换荧光粉时，该第一截止滤波片为短波通截止滤波片；反之，为长波通截止滤波片。As a technical solution to realize the concept of the present invention, a backlight module for high-efficiency fluorescent conversion is provided, including a bottom box, a heat dissipation base at the bottom of the bottom box, and a plurality of LEDs distributed on the heat dissipation base and a plurality of bottom surrounding a Reflective cup or collimating lens of LED; the top opening of the bottom box is closed by a phosphor layer with a predetermined thickness, and the phosphor layer is scattered or coated with phosphor; A light diffusion sheet and a liquid crystal display located on the light diffusion sheet; especially, it also includes a first cut-off filter, interposed between each of the reflective cups or the top of the collimating lens and the phosphor layer, so that the Light in the predetermined wavelength range in the bottom box penetrates the cut-off filter at an incident angle smaller than a predetermined value; when the phosphor is a down-conversion phosphor, the first cut-off filter is a short-pass cut-off filter; otherwise, For the long-wave pass cut-off filter.

上述方案中，所述高效荧光转换的背光模块还包括与所述第一截止滤波片波通特性相反的第二截止滤波片，介于所述荧光粉层与所述光扩散片之间，从而所述荧光粉层中未被荧光粉吸收的所述预定波长范围的光被反射回所述荧光粉层，所述荧光粉激发的光子以小于第二预定值的入射角穿透该第二截止滤波片。In the above solution, the backlight module for high-efficiency fluorescent conversion further includes a second cut-off filter having opposite wave-pass characteristics to the first cut-off filter, interposed between the phosphor layer and the light diffusion sheet, so that Light in the predetermined wavelength range not absorbed by the phosphor in the phosphor layer is reflected back to the phosphor layer, and photons excited by the phosphor penetrate the second cut-off at an incident angle smaller than a second predetermined value. filter.

上述方案中，所述不同材料的荧光粉在荧光粉层中按块分布或涂覆，分别罩在一反射杯或准直透镜的顶部。In the above solution, the phosphor powders of different materials are distributed or coated in blocks in the phosphor powder layer, and respectively covered on the top of a reflective cup or collimating lens.

采用上述各技术方案，荧光转换的效率得到大幅提高，在特定的场合下还能获得预期的纯净光输出，同时产品结构及工艺保持简单优势，便于低成本实现。Using the above-mentioned technical solutions, the efficiency of fluorescence conversion is greatly improved, and the expected pure light output can be obtained in specific occasions. At the same time, the product structure and process maintain the advantages of simplicity, which is convenient for low-cost realization.

附图说明  图1a、b、c、d是现有LED光源结构示意图Description of the drawings Figure 1a, b, c, d are schematic diagrams of the structure of the existing LED light source

          图2是现有LED光源的结构示意图       Figure 2 is a structural schematic diagram of an existing LED light source

          图3是现有背光模块结构示意图       Figure 3 is a structural schematic diagram of the existing backlight module

          图4是本发明LED光源结构示意图       Figure 4 is a structural schematic diagram of the LED light source of the present invention

          图5是图4中截止滤波片特性示意图Figure 5 is a schematic diagram of the cut-off filter characteristics in Figure 4

          图6是本发明白光LED光源实施例之一示意图        Figure 6 is a schematic diagram of an embodiment of the white LED light source of the present invention

          图7是本发明白光LED光源实施例之二示意图        Figure 7 is a schematic diagram of the second embodiment of the white LED light source of the present invention

          图8是本发明白光LED光源实施例之三示意图        Figure 8 is a schematic diagram of the third embodiment of the white LED light source of the present invention

          图9是本发明背光模块结构示意图       Figure 9 is a structural schematic diagram of the backlight module of the present invention

          图10是本发明背光模块实施例之一示意图Figure 10 is a schematic diagram of an embodiment of the backlight module of the present invention

          图11是本发明背光模块实施例之二示意图Figure 11 is a schematic diagram of the second embodiment of the backlight module of the present invention

具体实施方式  下面，结合附图所示之最佳实施例进一步阐述本发明。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Below, the present invention will be further described in conjunction with the preferred embodiments shown in the accompanying drawings.

如图4所示，本发明LED光源的结构包括LED 14，为表面贴装的发光二极管(包括单个发光二极管或列阵式发光二极管)，或者为在衬底15上形成的发光芯片(包括单个或阵列式发光芯片)。该LED 14设置在反射杯13的底部；所述反射杯13可以采用任何已知技术来实现，比如图1中具有镜面反射或漫反射杯壁的反射杯，也可以用任何已知技术来替代，比如图2中的透射杯2’，或者同样具有光汇聚功能的准直透镜(为了叙述方便，以下所提到的反射杯，若不另加以说明，也可以指准直透镜)。As shown in Figure 4, the structure of LED light source of the present invention comprisesLED 14, is the light-emitting diode (comprising single light-emitting diode or array type light-emitting diode) of surface mounting, or is the light-emitting chip (comprising single light-emitting diode) formed onsubstrate 15 or array light-emitting chips). ThisLED 14 is arranged on the bottom ofreflective cup 13; Describedreflective cup 13 can adopt any known technology to realize, such as the reflective cup with specular reflection or diffuse reflection cup wall among Fig. 1, also can replace with any known technology , such as the transmissive cup 2' in FIG. 2, or a collimating lens that also has the function of converging light (for the convenience of description, the reflective cup mentioned below may also refer to the collimating lens if not otherwise specified).

在所述反射杯13的顶部设置一预定厚度的荧光粉层11，均匀散布或涂覆着荧光粉。第一截止滤波片12设置在所述荧光粉层11和所述反射杯13顶部之间，该截止滤波片12具有如图5曲线a或b的特性；以所述荧光粉为绿色下转换荧光转换材料(激发的绿光波长大于LED发射的蓝光波长)为例，该第一截止滤波片12当具有如曲线a的特性，为短波通截止滤波片，允许波长为500nm以下的蓝光将以小于预定值(由该截止滤波片的光学特性所决定)的入射角穿透该截止滤波片，这样LED 14发射的较大角度范围的蓝光经反射杯13的聚光作用，大部分将以较小角度(例如15-25度)入射到所述第一截止滤波片12并穿透之，激励所述荧光粉发射出绿色荧光(波长505～550nm)，该绿色荧光因为波长大于曲线a的转折点波长(500nm)，部分射向所述第一截止滤波片12的光子将被反射输出，从而提高该光源中的绿色荧光萃取效率。当所述荧光粉为绿色上转换荧光转换材料时，所述第一截止滤波片12应具有如曲线b的相反波通特性，为长波通截止滤波片，LED 14发射的光只有波长大于为500nm以上的能以小于预定值的入射角穿透该滤波片12。Afluorescent powder layer 11 with a predetermined thickness is arranged on the top of the reflectingcup 13, and the fluorescent powder is uniformly scattered or coated. The first cut-off filter 12 is arranged between thephosphor layer 11 and the top of thereflection cup 13, and the cut-off filter 12 has the characteristics of curve a or b in Figure 5; Conversion material (excited green light wavelength is greater than the blue light wavelength emitted by LED) is an example, when the first cut-off filter 12 has characteristics such as curve a, it is a short-wave pass cut-off filter, allowing blue light with a wavelength of less than 500nm to pass The angle of incidence of the predetermined value (determined by the optical characteristics of the cut-off filter) penetrates the cut-off filter, so that the blue light of the larger angle range emitted by theLED 14 will be mostly absorbed by thereflection cup 13 with a smaller Angle (such as 15-25 degrees) is incident on the first cut-offfilter 12 and penetrates it, exciting the phosphor to emit green fluorescence (wavelength 505-550nm), the green fluorescence is because the wavelength is greater than the turning point wavelength of curve a (500nm), part of the photons incident on the first cut-off filter 12 will be reflected and output, thereby improving the extraction efficiency of green fluorescence in the light source. When the fluorescent powder is a green up-conversion fluorescent conversion material, the first cut-off filter 12 should have the opposite wave-pass characteristic as curve b, which is a long-wave pass cut-off filter, and the light emitted by theLED 14 has only a wavelength greater than 500nm The above can penetrate thefilter 12 at incident angles smaller than a predetermined value.

为了进一步提高荧光转换效率，本发明LED光源还可以包括第二截止滤波片10，具有与所述第一截止滤波片12相反的波通特性，设置在所述荧光粉层11的上面，以第一截止滤波片12具有特性曲线a、第二截止滤波片10具有特性曲线b为例，二者具有大致一致的转折点，从而该荧光粉层11中未被荧光粉完全吸收的、小于500nm波长的蓝光被第二截止滤波片10反射，并被所述绿色荧光转换材料所吸收并激发绿光，而满足第二预定入射角(由所述第二截止滤波片10光学特性决定)要求或经多次反射后才满足该入射角要求的绿光将穿透该第二截止滤波片10，提供绿色光输出。该实施例中，荧光转换效率得到提高的同时，可以输出纯净的单色绿光。In order to further improve the fluorescent conversion efficiency, the LED light source of the present invention can also include a second cut-off filter 10, which has a wave-pass characteristic opposite to that of the first cut-off filter 12, and is arranged on thephosphor layer 11 to form a second cut-off filter. One cut-off filter 12 has characteristic curve a, and the second cut-off filter 10 has characteristic curve b as an example. The blue light is reflected by the second cut-offfilter 10, and is absorbed by the green fluorescent conversion material to excite the green light, so as to meet the second predetermined incident angle (determined by the optical characteristics of the second cut-off filter 10) or after multiple The green light that satisfies the requirement of the incident angle after the second reflection will pass through the second cut-off filter 10 to provide green light output. In this embodiment, while the fluorescence conversion efficiency is improved, pure monochromatic green light can be output.

若在所述第一截止滤波片12与所述反射杯13顶部之间留一空气隙，还可以使所述荧光粉层中未被吸收利用的角度较大的蓝光被第一截止滤波片12在空气界面处发生全反射，再次返回所述绿色荧光转换材料中，有助于提高荧光转换率。If an air gap is left between the first cut-off filter 12 and the top of thereflective cup 13, the blue light with a larger angle that is not absorbed and utilized in the phosphor layer can be absorbed by the first cut-off filter 12. Total reflection occurs at the air interface and returns to the green fluorescence conversion material again, which helps to improve the fluorescence conversion rate.

经过实验验证，采用本发明结构的LED光源在增加第一截止滤波片12后，荧光转换效率平均可提高约115％，增加第二截止滤波片10后，荧光转换效率平均可提高约160％。It has been verified by experiments that the fluorescence conversion efficiency of the LED light source adopting the structure of the present invention can be increased by about 115% on average after the first cut-off filter 12 is added, and the fluorescence conversion efficiency can be increased by about 160% on average after the second cut-off filter 10 is added.

本发明中所述荧光粉包括红、黄、绿、蓝单色荧光转换材料中的一种、两种、三种或三种以上；因此，除了上述实施例中产生绿光外，本发明还可以通过截止滤波片、荧光粉和LED的匹配组合来低成本产生白光。Phosphor powder described in the present invention includes one, two, three or more than three of red, yellow, green and blue monochrome fluorescent conversion materials; White light can be produced at low cost through a matched combination of cut-off filters, phosphors, and LEDs.

图6为实现白光实施例之一，所述荧光粉包括红、绿、蓝各一种单色荧光下转换材料，在荧光粉层21中均匀混合；所述LED 24发射紫外光(波长250～420nm)，经反射杯23汇聚后，穿透UV短波通截止滤波片(具有类似图5曲线a的光学特性，允许波长较短的紫外光穿透)，从而所述三种荧光粉分别激发产生红、绿、蓝光，穿透RGB长波通截止滤波片20(具有类似图5曲线b的光学特性，允许波长较长的红、绿、蓝光穿透)而混合成白光输出。在该实施例中，所述第一和第二截止滤波片的波通特性相反，但转折点并不一致。Fig. 6 is to realize one of white light embodiment, described fluorescent powder comprises red, green, blue each a kind of monochromatic fluorescent down-converting material, mixes uniformly influorescent powder layer 21; DescribedLED 24 emits ultraviolet light (wavelength 250～ 420nm), after being converged by thereflection cup 23, it penetrates the UV short-wave pass cut-off filter (having an optical characteristic similar to the curve a in Fig. 5, which allows the penetration of ultraviolet light with a shorter wavelength), so that the three phosphors are respectively excited to generate Red, green, and blue light pass through the RGB long-wavelength cut-off filter 20 (with optical characteristics similar to curve b in FIG. 5 , allowing red, green, and blue light with longer wavelengths to pass through) to be mixed into white light output. In this embodiment, the wave-pass characteristics of the first and second cut-off filters are opposite, but the turning points are not the same.

图7为实现白光实施例之二。在该实施例中，所述荧光粉包括红、绿各一种单色荧光下转换材料，在荧光粉层31中均匀混合；所述LED34发射蓝光(波长420～480nm)，经反射杯33汇聚后，穿透蓝光短波通截止滤波片(具有类似图5曲线a的光学特性，允许波长较短的蓝光穿透)，从而所述两种荧光粉分别激发产生红、绿光，与未被吸收的部分蓝光一起混合成白光输出。Fig. 7 is the second embodiment of realizing white light. In this embodiment, the fluorescent powder includes red and green monochromatic fluorescent down-converting materials, which are uniformly mixed in thefluorescent powder layer 31; Afterwards, it passes through the blue light short-pass cut-off filter (having an optical characteristic similar to the curve a in Fig. 5, which allows blue light with a shorter wavelength to penetrate), so that the two phosphors are respectively excited to produce red and green light, and the unabsorbed Part of the blue light is mixed together into white light output.

图8为实现白光实施例之三。在该实施例中，所述荧光粉为一种黄色荧光下转换材料，在荧光粉层41中均匀分布；所述LED 44发射蓝光(波长420～480nm)，经反射杯43汇聚后，穿透蓝光短波通截止滤波片(具有类似图5曲线a的光学特性，允许波长较短的蓝光穿透)，从而所述荧光粉激发产生黄光，与未被吸收的部分蓝光一起混合成白光输出。Fig. 8 is the third embodiment of realizing white light. In this embodiment, the fluorescent powder is a yellow fluorescent down-converting material, which is evenly distributed in thefluorescent powder layer 41; Blue light short-wave pass cut-off filter (with optical characteristics similar to curve a in Figure 5, allowing blue light with a shorter wavelength to pass through), so that the phosphor is excited to generate yellow light, which is mixed with the unabsorbed part of blue light to form white light output.

本发明还可以用来设计具有高荧光转换效率的背光模组。如图3所示，现有背光模组包括底盒60，该底盒底部的散热基座62，以及分布在所述散热基座上的若干LED 61，所述底盒60的顶部开口被一预定厚度的荧光粉层63所封闭，该荧光粉层63散布或涂覆着荧光粉；还包括位于该荧光粉层之上的光扩散片64以及位于该光扩散片64之上的液晶显示屏65。该背光模组同样具有荧光转换不高的缺点。如图9所示，本发明背光模组在上述现有技术--底盒55，散热基座58，LED 57，荧光粉层53，光扩散片52及LCD 50的基础上，增加若干底部包围一LED的反射杯或准直透镜56，以及介于各所述反射杯或准直透镜56顶部和所述荧光粉层53之间的第一截止滤波片54，使所述底盒55内预定波长范围的光以小于预定值的入射角穿透该截止滤波片54，并反射所述荧光粉层53中的激发光子，可以提高荧光利用率，从而增强LCD的显示亮度。同样，再增加与所述第一截止滤波片54波通特性相反的第二截止滤光片51，介于所述荧光粉层53与所述光扩散片52之间，通过双滤光片组成的腔结构，对未被荧光粉吸收的来自LED的光进行多次反射，反复激励所述荧光粉，可以大大提高荧光粉对LED光子的吸收利用率。以及在所述第一截止滤波片54与所述反射杯或准直透镜56顶部之间留一空气隙，以全反射所述荧光粉层中未被荧光粉吸收的所述预定波长范围的光，诸如此类提高荧光转换效率的措施，因均已在上述LED光源中涉及，不再赘述。The invention can also be used to design a backlight module with high fluorescence conversion efficiency. As shown in Figure 3, the existing backlight module comprises abottom box 60, a heat dissipation base 62 at the bottom of the bottom box, and several LEDs 61 distributed on the heat dissipation base, and the top opening of thebottom box 60 is covered by a Closed by a phosphor layer 63 of predetermined thickness, the phosphor layer 63 is scattered or coated with phosphor; it also includes a light diffusion sheet 64 on the phosphor layer and a liquid crystal display on the light diffusion sheet 64 65. The backlight module also has the disadvantage of low fluorescence conversion. As shown in Figure 9, on the basis of the above-mentioned prior art-thebottom box 55, theheat dissipation base 58, theLED 57, the phosphor layer 53, thelight diffusion sheet 52 and the LCD 50, the backlight module of the present invention increases some bottom surrounds A reflective cup or collimatinglens 56 of an LED, and a first cut-off filter 54 between each of the reflective cups or collimatinglens 56 tops and the phosphor layer 53, so that predetermined The light in the wavelength range penetrates the cut-off filter 54 at an incident angle smaller than a predetermined value, and reflects the excited photons in the phosphor layer 53, which can improve the utilization rate of the phosphor, thereby enhancing the display brightness of the LCD. Similarly, add a second cut-off filter 51 opposite to the pass characteristic of the first cut-off filter 54, between the phosphor layer 53 and thelight diffusion sheet 52, and form a double filter The cavity structure reflects the light from the LED that is not absorbed by the phosphor multiple times, and repeatedly excites the phosphor, which can greatly improve the absorption and utilization rate of the LED photons by the phosphor. And leave an air gap between the first cut-off filter 54 and the reflective cup or the top of the collimatinglens 56 to totally reflect the light in the predetermined wavelength range not absorbed by the phosphor in the phosphor layer , and other measures to improve the fluorescence conversion efficiency have been involved in the above-mentioned LED light source, and will not be repeated here.

本发明背光模块中，所述荧光粉也可以包括红、黄、绿、蓝单色荧光转换材料中的一种、两种、三种或三种以上；所述LED(包括表面贴装的发光二极管，或在衬底上形成的发光芯片)的发光波长可以选择250～480nm。除了图9中选用包括红、绿、蓝各一种单色荧光下转换材料的荧光粉进行均匀混合，及发射蓝光的LED 57与蓝光短波通截止滤波片54来产生白光输出外，图10给出了用包括红、绿、蓝各一种单色荧光下转换材料的荧光粉来产生白光的又一具体实施例。在该实施例中，所述三种荧光粉在荧光粉层中按块分布或涂覆，分别罩在一反射杯或准直透镜的顶部。第一截止滤波片和第二截止滤波片可以用整片的UV短波通截止滤波片和RGB长波通截止滤波片，也可以如该图所述，采用分片的UV短波通截止滤波片和相应的红、绿、蓝长波通截止滤波片。图11给出了用包括红、绿各一种单色荧光下转换材料的荧光粉来产生白光的又一实施例，在该实施例中，省掉了第二截止滤波片，从而荧光粉激发的红、绿光和未被吸收的LED激发蓝光混合成白光输出，简化了结构，成本更低。In the backlight module of the present invention, the fluorescent powder may also include one, two, three or more than three of red, yellow, green, and blue monochromatic fluorescent conversion materials; The light emitting wavelength of the diode, or the light emitting chip formed on the substrate) can be selected from 250 to 480 nm. Except that in Fig. 9, the phosphor powders comprising red, green and blue monochrome fluorescent down-conversion materials are uniformly mixed, and the blue-emittingLED 57 and the blue short-wave cut-off filter 54 are used to produce white light output, Fig. 10 shows Yet another specific embodiment is shown in which white light is generated by using phosphor powders including red, green and blue monochromatic fluorescent down-converting materials. In this embodiment, the three kinds of phosphors are distributed or coated in blocks in the phosphor layer, and respectively covered on the top of a reflective cup or a collimating lens. The first cut-off filter and the second cut-off filter can use the whole piece of UV short-wave pass cut-off filter and RGB long-wave pass cut-off filter, or as described in the figure, use the sliced UV short-wave pass cut-off filter and corresponding Red, green and blue longpass cut-off filters. Fig. 11 has given yet another embodiment that white light is produced by phosphor powder comprising a single-color fluorescent down-conversion material of red and green. In this embodiment, the second cut-off filter is omitted, so that the phosphor powder excites The red and green light and the unabsorbed LED excited blue light are mixed into white light output, which simplifies the structure and lowers the cost.

本发明LED光源或背光模块中，所述荧光粉层中的荧光粉包括下转换荧光粉和上转换荧光粉，可以是通过化学合成的无机或有机粉状荧光颗粒，这些颗粒可以用胶体(例如透明树脂)混合，从而以贴膜的形式提供，或用涂覆的方式附着在所述第一截止滤波片或第二截止滤波片的一面。In the LED light source or backlight module of the present invention, the fluorescent powder in the fluorescent powder layer includes down-conversion fluorescent powder and up-conversion fluorescent powder, which can be inorganic or organic powdery fluorescent particles by chemical synthesis, and these particles can be made of colloid (such as transparent resin) to be provided in the form of a pasting film, or attached to one side of the first cut-off filter or the second cut-off filter by coating.

采用本发明结构的LED光源或背光模块可以大大降低对LED波长的分选要求，即使在使用过程中LED波长有所退化，也大体能保持该LED与荧光粉之间的波长匹配，从而降低产品的成本。The LED light source or backlight module adopting the structure of the present invention can greatly reduce the sorting requirements for LED wavelengths. Even if the LED wavelengths degrade during use, they can generally maintain the wavelength matching between the LEDs and the phosphor powder, thereby reducing the product cost. the cost of.

Claims (13)

1. a high-efficiency fluorescence conversion LED light source comprises at least one LED, is arranged on the bottom of a reflector or collimating lens; Be provided with the phosphor powder layer of a predetermined thickness at the top of this reflector or collimating lens, uniformly dispersing or applying fluorescent material; It is characterized in that:

Also comprise first by filter plate, between described phosphor powder layer and described reflector or collimating lens top, thereby the light of predetermined wavelength range penetrates this by filter plate with the incidence angle less than predetermined value in this reflector or the collimating lens;

When described fluorescent material is the down-conversion fluorescent powder, this first by filter plate be that short-pass is ended filter plate; Otherwise, for long-pass is ended filter plate.

2. according to the described high-efficiency fluorescence conversion LED light source of claim 1, it is characterized in that:

Also comprise with described first by the logical characteristic of filter plate ripple opposite second by filter plate, be arranged on described phosphor powder layer above, thereby the photon that described fluorescent material excites penetrates this second by filter plate with the incidence angle less than second predetermined value.

3. according to the described high-efficiency fluorescence conversion LED light source of claim 2, it is characterized in that:

Described first by filter plate and second roughly consistent by the logical breakover point of the ripple of filter plate, thereby the light of the described predetermined wavelength range that is not absorbed by fluorescent material in the described phosphor powder layer is ended the described phosphor powder layer of filter plate reflected back by described second.

4. according to claim 2 or 3 described high-efficiency fluorescence conversion LED light source, it is characterized in that:

Described first by being an air-gap between filter plate and described reflector or the collimating lens top, thereby the light of the described predetermined wavelength range that is not absorbed by fluorescent material in the described phosphor powder layer first is ended filter plate and returns described phosphor powder layer in the total reflection of air interface place by this.

5. according to claim 2 or 3 described high-efficiency fluorescence conversion LED light source, it is characterized in that:

Described phosphor powder layer is the mixture that fluorescent material and transparent refractive index match resin or liquid are formed with predetermined ratio, and fluorescent material is graininess and intersperses among wherein.

6. according to the described high-efficiency fluorescence conversion LED light source of claim 1, it is characterized in that:

Described LED is surface-pasted single light-emitting diode or array formula light-emitting diode, perhaps single luminescence chip or the array formula luminescence chip for forming on substrate.

7. according to the described high-efficiency fluorescence conversion LED light source of claim 1, it is characterized in that:

Described fluorescent material comprise in the monochromatic fluorescence transition materials such as red, yellow, green, blue a kind of, two kinds, more than three kinds or three kinds.

8. the backlight module of high-efficiency fluorescence conversion comprises end box, the cooling base of this box bottom, end, and be distributed in reflector or the collimating lens that some LED on the described cooling base and some bottoms surround a LED; The open top of box of the described end is sealed by the phosphor powder layer of a predetermined thickness, and this phosphor powder layer scatters or applying fluorescent material; Also comprise and be positioned at the light diffusing sheet on the described phosphor powder layer and be positioned at LCDs on this light diffusing sheet; It is characterized in that:

Also comprise first by filter plate, between each described reflector or collimating lens top and described phosphor powder layer, thereby the light of predetermined wavelength range penetrates this by filter plate with the incidence angle less than predetermined value in the box of the described end;

When described fluorescent material adopt be the down-conversion fluorescent powder time, this first is that short-pass is ended filter plate by filter plate; Otherwise, for long-pass is ended filter plate.

9. the backlight module of described according to Claim 8 high-efficiency fluorescence conversion is characterized in that:

Also comprise with described first by the logical characteristic of filter plate ripple opposite second by filter plate, between described phosphor powder layer and described light diffusing sheet, thereby the light of the described predetermined wavelength range that is not absorbed by fluorescent material in the described phosphor powder layer is reflected back toward described phosphor powder layer, and the light that described fluorescent material excites penetrates this second by filter plate with the incidence angle less than second predetermined value.

10. it is characterized in that according to Claim 8 or the backlight module of 9 described high-efficiency fluorescences conversion:

Described first by being an air-gap between filter plate and described reflector or the collimating lens top, thereby the light of the described predetermined wavelength range that is not absorbed by fluorescent material in the described phosphor powder layer is returned described phosphor powder layer by total reflection.

11. the backlight module of described according to Claim 8 high-efficiency fluorescence conversion is characterized in that:

Described LED is surface-pasted light-emitting diode, perhaps the luminescence chip for forming on substrate.

12. according to Claim 8 or the backlight module of 9 described high-efficiency fluorescences conversion, it is characterized in that:

Described fluorescent material comprise in the monochromatic fluorescence transition material of red, green, blue a kind of, two or three; The emission wavelength of described LED is 250～480nm.

13. the backlight module according to the described high-efficiency fluorescence conversion of claim 12 is characterized in that:

The fluorescent material of described different materials is pressed the piece distribution or is applied in phosphor powder layer, cover on the top of a reflector or collimating lens respectively.

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