TWI621282B - Light-emitting diode device with fluorine-containing phosphor composition - Google Patents

Abstract

The invention discloses a light-emitting diode using a fluorine-containing fluorescent material, which comprises a light-emitting diode chip driven by a power source to emit discontinuous light, wherein the discontinuous light includes a light-emitting time and a blank time of no light emission; and setting A fluorine-containing phosphor material on a light-emitting diode wafer. The fluorine-containing phosphor material absorbs discontinuous light emitted from the light-emitting diode wafer and emits a fluorescent light, wherein the fluorine-containing fluorescent material has a fluorescence half-life and the fluorescence half-life is greater than or equal to the blank time.

Description

Light-emitting diode using fluorine-containing fluorescent material

The invention relates to a light-emitting diode using a fluorine-containing fluorescent material, in particular to a fluorine-containing fluorescent material containing a blank time with a fluorescence half-life greater than or equal to that of the light-emitting diode, which can be filled with fluorescence. Time to reduce the flicker phenomenon of the light-emitting diode.

At present, about 20% of the global electricity consumption of the LEDs comes from lighting. The incandescent lamps used in the traditional lighting field have high power consumption, low luminous efficiency and short service life. Governments all recognize that the incandescent lamps are disabled for efficient energy conservation. Pipes, so incandescent lamps are listed as the primary control focus. In 2007, Australia took the lead in proposing the elimination of incandescent lamps as an energy-saving policy. China has phased off incandescent lamps in 2012. By 2015, more than 9 major countries including the United States, Britain, Japan and the European Union will be completely banned. The ban on incandescent lamps has enabled white light-emitting diodes to replace traditional incandescent lighting on a large scale within a few years.

Because the light-emitting diode has higher luminous efficiency (higher than high-pressure sodium lamp or mercury lamp), long life (up to 100,000 hours or more, more than 5 times that of high-pressure sodium lamp and 10 times or more of mercury lamp), small volume (strong plasticity, With the application equipment miniaturization), low power consumption (power consumption is 1/8 to 1/10 of the general bulb, 1/2 of the fluorescent lamp, which can save about 50~90% of electricity), environmental protection, no mercury, low calorific value (heat during operation The low radiation level and good reaction speed (high frequency operation) can overcome the problems faced by incandescent lamps and fluorescent lamps in the past. Because the light-emitting diode has both power saving and environmental protection effects, it is called "the green lighting of the new generation."

Early development of DC light-emitting diodes is a market trend. When using LEDs for commercial power (AC), it is necessary to convert AC power to DC power by converting equipment such as transformers and rectifiers to drive the LEDs under AC. Normal operation, however, such conversion equipment will generate a large amount of thermal energy when operating, resulting in problems such as shortened component life, power loss, and reduced luminous efficiency, even if the life of the LED can be as long as 100,000 hours or more, due to the general conversion equipment life. Only 20,000 hours, making the LEDs replaced in advance or generating additional replacement conversion equipment costs, is quite uneconomical.

Therefore, the technology of the AC light-emitting diode has been developed to eliminate the bulky and heavy-duty conversion equipment, and can save 15-30% of the power loss caused by the DC/AC conversion. In addition, the AC LED has Low circuit energy loss, prevention of electrostatic shock and other properties can improve overall luminous efficiency.

However, the AC light-emitting diode will generate periodic blinking (stroboscopic) under AC constant voltage driving. For example, the AC light-emitting diode operates at an AC environment with a voltage of 80 volts and a frequency of 120 Hertz (Hz). It will form 1/120 second, which is equivalent to the time difference of 8.3 milliseconds, causing the phenomenon of illuminating and flickering, which is easy to cause eye fatigue of the user when used for general illumination.

The invention discloses a light-emitting diode using a fluorine-containing fluorescent material, comprising a light-emitting diode chip driven by a power source to emit discontinuous light, wherein the light-emitting diode chip is not connected The continuation light includes a luminescence time of luminescence and a blank time of no luminescence; and a fluorofluorescent material disposed on the illuminating diode chip. The fluorine-containing phosphor material absorbs discontinuous light emitted from the light-emitting diode wafer and emits fluorescence, wherein the fluorine-containing phosphor material has a fluorescence half-life greater than or equal to the blank time. Since the fluorescence half-life of the fluorine-containing fluorescent material is greater than or equal to the blank time, the fluorescence can fill the blank time and reduce the light flicker caused by the periodic extinction of the light-emitting diode.

In addition, the present invention further discloses a light-emitting diode using a fluorine-containing phosphor material, comprising a light-emitting diode chip electrically connected to an alternating current power source by a rectifying circuit and one of the light-emitting diode chips disposed on the light-emitting diode chip. Fluoride fluorescent material. Forming a plurality of light-emitting units on the substrate of the light-emitting diode chip, and the plurality of light-emitting units are electrically connected in series, parallel or series-parallel, and are periodically turned on and off according to the input of the alternating current power source, each of which is periodically turned on and off. The periodic non-conduction time causes a blank time when the light-emitting unit emits light, and the fluorine-containing fluorescent material absorbs the light emitted by the first light-emitting diode or the second light-emitting diode, and then emits a fluorescent light, due to the fluorescent light of the fluorine-containing fluorescent material. The light half-life is greater than or equal to the blank time, and the fluorescence can fill the blank time, and the blanking time is reduced to cause the flashing of the LED chip.

Wherein, the fluorine-containing fluorescent material has the general formula A2[MF6]:Mn4+, A is selected from the group consisting of Li, Na, K, Rb, Cs, and NH4, and M is selected from the group consisting of Ge, Si, Sn, and Ti. A group of Zr. The fluorescent characteristics of the fluorine-containing fluorescent material may include: excitation light having a wavelength of from 350 to 500 nm, a radiation wavelength of from 600 to 700 nm, a fluorescence half-life of milliseconds (msec), and two excitation peaks.

1‧‧‧Light Emitter Wafer

10‧‧‧Substrate

12‧‧‧Lighting diode

14‧‧‧First Light Emitting Diode

16‧‧‧Second light-emitting diode

2‧‧‧Fluorescent Fluorescent Materials

3‧‧‧AC power supply

30‧‧‧Filter electrolytic capacitor

32‧‧‧Bridge rectifier circuit

T‧‧‧ blank time

The first A is a schematic perspective view (1) of an embodiment of the present invention.

The first B diagram is a schematic circuit diagram of an embodiment of the invention.

The first C is a schematic view of a three-dimensional structure (2) according to another embodiment of the present invention.

The first D diagram is a schematic perspective view of a three-dimensional structure (3) according to another embodiment of the present invention.

FIG. 2A is a schematic circuit diagram of another embodiment of the present invention.

The second B diagram is a current distortion diagram of another embodiment of the present invention.

The third A is a X-ray diffraction diagram of a fluorine-containing fluorescent material according to still another embodiment of the present invention.

Figure 3B is an excitation and emission spectrum of a fluorine-containing fluorescent material according to still another embodiment of the present invention.

The third C is a graph showing the relative ratio of the emission spectrum area of the fluorine-containing phosphor material to the heating temperature according to still another embodiment of the present invention.

The third D is a fluorescence attenuation diagram of the fluorine-containing fluorescent material according to still another embodiment of the present invention.

The invention relates to a light-emitting diode using a fluorine-containing fluorescent material, wherein the fluorine-containing fluorescent material has a long fluorescence half-life, and the fluorescent light emitted after the light absorption can fill the blank time when the light-emitting diode emits light. Reduce the flicker of the LED.

Please refer to FIG. 1A and FIG. 2B, which are schematic diagrams (1) and circuit diagrams of a first embodiment of the present invention. As shown in the figure, an embodiment of the present invention uses an alternating current light-emitting diode of a fluorine-containing phosphor material, which comprises at least one light-emitting diode wafer 1 and a fluorine-containing phosphor material 2, and the light-emitting diode wafer 1 is electrically Connected to an AC power source 3, and directly drives the LED chip 1 with the AC power source 3, and the fluorine-containing phosphor material 2 is disposed on the LED body 1 (the first A picture is individually packaged in each of the first illuminations) The manner of the diode 14 and each of the second light-emitting diodes 16). The LED chip 1 includes a substrate 10 and a plurality of first LEDs 14 and a plurality of LEDs 16 respectively disposed on the substrate 10. The first light-emitting diodes 14 and the second light-emitting diodes 16 can be electrically connected in series, in parallel or in series and parallel. As shown in FIG. B, in the embodiment, the first LEDs 14 are electrically connected to each other in series, and the second LEDs 16 are electrically connected to each other in series, in series. The first light-emitting diodes 14 and the second light-emitting diodes 16 connected in series are electrically connected in parallel, and the first light-emitting diodes 14 and the second light-emitting diodes 16 are electrically connected in opposite directions.

Since the first light emitting diode 14 and the second light emitting diode 16 are opposite in conduction direction, the first light emitting diode 14 is periodically turned on and off when the current input of the alternating current power source 3 is consistent, and the second light emitting second The pole body 16 consistently performs periodic conduction and non-conduction opposite to the first light-emitting diode 14. In this embodiment, when the voltage or current of the alternating current power source 3 is input in a positive half cycle, the first light emitting diode 14 is turned on to emit light, and the second light emitting diode 16 is not turned on in an extinguished state; conversely, when When the voltage or current of the AC power source 3 is input in a negative half cycle, the second LED 26 is turned on to emit light, and the first LED 16 is not turned on and is extinguished. Because the time difference between the first light-emitting diode 14 and the second light-emitting diode 16 being turned on and off and the second light-emitting diode 16 being non-conducting to the first light-emitting diode 14 are caused by the time difference The light emission of the diode wafer 1 generates a blank time, so that the light-emitting diode wafer 1 periodically appears to blink briefly.

When the first light-emitting diode 14 or the second light-emitting diode 16 emits light, the fluorine-containing phosphor material 2 absorbs light emitted from the first light-emitting diode 14 or the second light-emitting diode 16 to be excited and discharged. A fluorescent light, because the fluorine-containing fluorescent material 2 in the embodiment of the present invention has a fluorescence half-life greater than or equal to the blank time, so that the blank time can be filled when the fluorescent light is generated, so that the light-emitting diode wafer 1 is in the blank time. flicker The phenomenon becomes less obvious.

The first light-emitting diode 14 and the second light-emitting diode 16 used in this embodiment may be the same blue light-emitting diode or ultraviolet light-emitting diode. In another embodiment, the first light emitting diode 14 is a blue light emitting diode, and the second light emitting diode 16 is a red light emitting diode. In this case, the fluorine fluorescent material 2 only needs to be disposed in the first Above one of the light-emitting diodes 14, there is no need to be disposed on the second light-emitting diode 16. The red fluorescent light emitted by the fluorine-containing fluorescent material 2 after being excited by the blue light emitted by the first light-emitting diode 14 can be connected or superposed on the red light emitted by the second light-emitting diode 16.

Through the arrangement of the above components, the AC light-emitting diode of the fluorine-containing fluorescent material disclosed in the embodiment of the present invention can fill the light-emitting diode under the AC power source by the fluorescent light emitted by the fluorine-containing fluorescent material with a long half-life of fluorescence. The periodic non-conduction leads to the blanking time of the luminescence interruption, which reduces the degree of flickering of the illuminating LED light, and can improve the problem that the user's eyes are easily fatigued by the high-frequency flicker when the conventional AC illuminator emits light.

The first light-emitting diode 14 can also be disposed in the embodiment of the present invention, except that the first light-emitting diode 14 and the second light-emitting diode 14 are respectively disposed on the substrate 10 as shown in FIG. The second LEDs 16 are epitaxially formed on the substrate 10, and electrically connected to electrically or electrically connect the LEDs in series, in parallel, or in series and in parallel to form the LEDs 1. The first light-emitting diodes 14 and the second light-emitting diodes 16 on the light-emitting diode chip 1 can be respectively disposed on the light-emitting diodes as shown in FIG. As shown in the first D diagram, the fluorine-containing phosphor material 2 is simultaneously provided on the plurality of light-emitting diodes 14 and 16.

Please refer to FIG. 2A and FIG. 2B, which are circuit diagrams and current distortion diagrams of the second embodiment of the present invention. As shown in FIG. 2A, in this embodiment, An AC power source 3 is electrically connected to a filter electrolytic capacitor 30 and a bridge rectifier circuit 32. The plurality of LEDs 12 are electrically connected to each other in series, parallel or series-parallel, and then electrically connected to the filter electrolytic capacitor 30. As shown in the previous embodiment, the LEDs 12 can be respectively disposed on the substrate 10 or formed on the substrate 10 in an epitaxial manner. In the present embodiment, the fluorine-containing phosphor material 2 may be respectively covered on each of the light-emitting diodes 12 or may be covered on each of the light-emitting diodes 12 at a time.

When an alternating current output from the alternating current power source 3 enters the bridge rectifier circuit 32, it is rectified into a direct current. When the direct current passes through the filter electrolytic capacitor 30, the charging and discharging behavior of the filter electrolytic capacitor 30 can achieve a filtering function, so that the original The voltage with a significant pulse (as shown in the second B diagram) becomes more gradual (as shown in the second panel B). However, the capacitive load characteristic caused by the charge and discharge behavior of the filter electrolytic capacitor 30 causes the bridge rectifier circuit 32 to have a current only in the rectifying diode of the bridge rectifier circuit 32 when the AC voltage output from the AC power source 3 reaches a peak value. Turning on (such as the IAC shown in Figure B), the conduction angle θ is reduced to about 60°, so that the DC current input to the LED chip 1 then exhibits a sharp pulse (current distortion), and the pulse width of the pulse is about Approximately one-third of the 1/2 period causes the light-emitting diode 12 to have a non-conducting blank time T between the two peaks of the alternating voltage.

When the alternating current source 3 is rectified into a direct current using the filter electrolytic capacitor 30 and the bridge rectifier circuit 32, the current distortion phenomenon will cause the blank time of the light-emitting diode 12 to be non-conductive, so it is disclosed in the embodiment of the present invention. The fluorine-containing fluorescent material is provided on the light-emitting diode 12 in a single package or in a whole package, and the fluorine-containing fluorescent material has a long fluorescence half-life characteristic, and the fluorine-containing fluorescent material is utilized. The fluorescent material emitted by the light material fills the blank time T.

The fluorine-containing fluorescent material has the general formula A2[MF6]: Mn4+, and A is selected from A group consisting of Li, Na, K, Rb, Cs, NH4, M is selected from the group consisting of Ge, Si, Sn, Ti, and Zr, and the fluorescence characteristics thereof may include: excitation light wavelengths between 350 and 500 The wavelength of the meter and the emitted light is between 600 and 700 nm, and the half-life of the fluorescence is in the order of milliseconds (msec). In one embodiment, the fluorescence half-life is between 5 and 15 milliseconds, and the excitation spectrum can have two excitation peaks. Wait.

In the third embodiment of the present invention, the synthesis method and the fluorescence characteristic test of the fluorine-containing fluorescent material will be described using K2Si1-XF6:MnX as an example. K2Si1-XF6: MnX uses Mn as the luminescent center, and its content ratio X is between 0.01 and 0.1, and can be prepared by the following two methods.

The first method is to synthesize K2Si1-XF6:MnX by chemical coprecipitation method. Firstly, K2MnF6 can be synthesized (synthesized by chemical reaction such as 2KMnO4+2KHF2+8HF+3H2O2→2K2MnF6+8H2O+3O2), and then K2MnF6 is poured into hydrogen containing K2SiF6. The product is stirred to obtain a coprecipitation reaction, and the yellow precipitate obtained by filtering the solution is washed with deionized water and acetone, and then dried to obtain the product K2Si1-XF6:MnX.

In the second method, K2Si1-XF6:MnX is prepared by ruthenium wafer etching. First, 6 g of potassium permanganate is added to 100 ml of hydrofluoric acid (concentration: 50%) and 100 ml of deionized water to prepare a solution, and then n-type or p-type The wafer is immersed in the above solution to carry out an etching reaction. During the process, the solution is not stirred. After reacting for 2 hours, the wafer is taken out and the residual solution is washed with deionized water. The powder is removed from the surface of the wafer using a spatula, and the powder is dried. The product K2Si1-XF6: MnX was obtained.

The above two processes for producing K2Si1-XF6:MnX are relatively simple, do not require high-temperature chemical reaction, are low in cost, and can be synthesized in a large amount and used in the light-emitting diode using the fluorine-containing fluorescent material in the embodiment of the present invention.

The third A is a X-ray diffraction diagram of K2Si1-XF6:MnX product synthesized by the aforementioned method 1 (chemical coprecipitation method) and K2SiF6 standard, K2Si1-XF6:MnX (taking K2Si0.95F6:Mn0.05 as an example) The X-ray diffraction pattern is shown in blue, and the X-ray diffraction pattern of the K2SiF6 standard is shown in red. Comparing the two, K2Si1-XF6:MnX prepared by chemical coprecipitation method has a pure phase and no impurity phase. K2SiF6 is a positive cubic unit lattice structure. Si is located at the center of six faces and eight apex angles. In K2Si1-XF6:MnX, the added Mn is substituted for the position of Si in the crystal lattice. It can be seen that Mn is successfully replaced. Part of the Si seat, and no secondary phase (Mn2O3) is generated.

The third B diagram is the excitation and emission spectrum of the aforementioned K2Si1-XF6:MnX product and the conventional red fluorescent powder CaAlSiN3:Eu. The excitation and emission spectra of the K2Si1-XF6:MnX product are shown in red, showing K2Si0.95F6: The Mn0.05 product can be effectively excited by blue light with a wavelength of 430-470 nm and has two excitation peaks. After excitation, it can emit red light fluorescence of 600-650 nm, and excitation and emission spectra of CaAlSiN3:Eu It is shown in black. It can be seen from the figure that the emission spectrum of the conventional red fluorescent powder CaAlSiN3:Eu extends to 750 nm, which forms excess infrared light, which causes self-absorption effect and reduces light-emitting efficiency due to the overlap of the excitation and the emission spectrum. And the short-wave portion of the emission spectrum overlaps with the excitation spectrum of the yellow-green fluorescent powder to cause a resorption effect, resulting in a decrease in the efficacy of the radiation. In contrast, the K2Si1-XF6:MnX emission spectrum disclosed in this embodiment is concentrated at 600-650 nm, which can improve the disadvantages of the conventional red fluorescent powder CaAlSiN3:Eu.

The third C is a plot of the relative area ratio of the radiation spectrum of the K2Si1-XF6:MnX product to the heating temperature. Since the heat easily causes the phosphor to be unstable, the measurement can prove the K2Si1-XF6 disclosed in the embodiment: The emission spectrum product of MnX fluorine-containing compound at the operating temperature (150~200 °C) of a general light-emitting diode The relative area ratio is still 103% to 104% compared with room temperature, indicating that the radiation intensity is still maintained at room temperature. The K2Si1-XF6:MnX product has high thermal stability and can overcome the conventional knowledge. The red fluorescent powder has the disadvantage of poor thermal stability, and is more suitable for use in the light-emitting diode of the present invention using a fluorine-containing fluorescent material.

The third D-graph is the fluorescence half-life diagram of the aforementioned K2Si1-XF6:MnX product. After exciting K2Si1-XF6:MnX with a wavelength of 460 nm excitation light, the fluorescence intensity of K2Si1-XF6:MnX radiation is continuously detected, such as As shown in the figure, the fluorescence half-life of the fluorine-containing fluorescent material K2Si1-XF6:MnX is 9.4 milliseconds, which can fill the 8.3 millisecond blank time generated by the alternating current conversion voltage, and greatly reduce the flicker phenomenon when the light-emitting diode wafer emits light, and Reduce the occurrence of overlays.

In summary, the light-emitting diode of the present invention using a fluorine-containing fluorescent material can pass through the fluorescent light emitted by the fluorine-containing fluorescent material having a long half-life of fluorescence to fill the blank time of the light-emitting diode to emit light, thereby reducing the light. The degree of flickering to avoid eye fatigue.

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and the equivalents and modifications of the features and spirits described in the claims of the present invention should be included. Within the scope of the patent application of the present invention.

Claims (10)

A light emitting diode comprising: a light emitting diode chip, comprising a substrate, and a plurality of light emitting units are epitaxially formed on the substrate, wherein the light emitting diode chip emits a periodic light of 350 to 500 nm. The periodic light includes a blank time; and a fluorine-containing phosphor material is disposed on the light-emitting diode wafer, and has the formula K ₂ Si _1-x F ₆ :Mn _x , and x is between 0.01 and 0.1 The fluorofluorescent material has a fluorescence half-life greater than or equal to the blank time, and the fluorescence half-life is between 5 and 15 msec, wherein the light-emitting diode system can be driven by an alternating current source. The light-emitting diode according to claim 1, wherein the plurality of light-emitting units are electrically connected to each other in series, in parallel, or in series-parallel. The light-emitting diode according to claim 1, wherein the excitation spectrum of the fluorine-containing fluorescent material has two excitation peaks. The light-emitting diode according to claim 1, further comprising a rectifier circuit electrically connected to the light-emitting diode chip. The light-emitting diode according to claim 4, further comprising an electrolytic capacitor electrically connected to the light-emitting diode chip and the rectifier circuit. The light-emitting diode according to claim 1, wherein the light-emitting diode chip comprises a first light-emitting diode and a second light-emitting diode, the first light-emitting diode and the first light-emitting diode The two light-emitting diodes conduct light in opposite periods of the alternating current. The light-emitting diode of claim 6, wherein the blank time is between the first light-emitting diode and the second light-emitting diode. The light-emitting diode according to claim 1, wherein the fluorine-containing phosphor material has a first radiation spectrum integral area between the operating temperature of the light-emitting diode wafer of 150 to 200 ° C, The fluorofluorescent material has a second emission spectrum integrated area when the operating temperature of the light emitting diode wafer is 25 ° C, and the integrated area of the first radiation spectrum is larger than the integrated area of the second radiation spectrum. The light-emitting diode according to claim 6, wherein the fluorine-containing phosphor materials on the first light-emitting diode and the second light-emitting diode are separated from each other. The light-emitting diode according to claim 6, wherein the fluorine-containing phosphor materials on the first light-emitting diode and the second light-emitting diode are not separated from each other.