Patent Application
20110316452
The present invention belongs to microelectronics technical field and relates to a method and device for generating white light, in particular to a method and device for generating white light based on field emission devices.
With the rapid development of lighting technology, the research and exploitation on the substitutes of traditional light source, i.e. energy-saving and environment-friendly green lighting sources, have become important tasks carried out in many countries competitively. While field emission device in the vacuum microelectronics filed has revealed a new approach for obtaining the green eco-lighting. The operating principle of the field emission device is as follows. In a vacuum environment, a forward voltage is applied on field emission arrays (FEAs) to form an accelerating field by an anode, then the electrons emitted by a cathode bombard the luminescent material on an anode plate after acceleration to emit light. Such device has wide operating temperature range (−40° C.-80° C.), short response time (<1 ms), simple structure, and is energy-saving and corresponds to the demands of green environment protection. Compared with the traditional fluorescent tube, the field emission light source is one kind of energy-saving green lighting source, which can avoid some disadvantages of the fluorescent tube such as environment pollution and visual fatigue caused by pulse flash while maintaining the advantages of fluorescent tube such as high efficiency and energy saving. Compared with LED, the field emission light source possesses more advantages in the aspects of high power and large scale lighting, and is probable to become a powerful competitor of LED in the aspect of high power light source since its field emission cathode can be prepared in large scale.
In the prior field emission white lighting technology, a white light is obtained through the excitation of an electron beam on three-colored fluorescent powder formed by the mixing of red, green and blue (R, G, B) fluorescent powder in appropriate proportions. However, when the mixture of the R, G, B fluorescent powder is used, the color coordinate of generated white light deviates obviously and the light source efficiency declines after a long time of the irradiation of the electron beam since the aging characteristics of each fluorescent material are different.
The objective of the present invention is to provide a method for generating white light, by which a long service time is realized and the obvious deviation of the color coordinate and the decline of light source efficiency are not easy to appear, aiming at the problems that in the prior lighting method, the color coordinate of generated white light deviates obviously and the light source efficiency declines after a long time of irradiation on the three-colored fluorescent powder since the aging characteristics of different fluorescent material are different.
Another objective of the present invention is to provide a lighting device for generating white light, by which a long service time is realized and the obvious deviation of the color coordinate and the decline of light source efficiency are not easy to appear, aiming at the problems that in the prior device, a white light is obtained through the excitation of an electron beam on three-colored fluorescent powder formed by the mixing of red, green and blue (R, G, B) fluorescent powder in appropriate proportions; the color coordinate of generated white light deviates obviously and the light source efficiency declines after a long time of irradiation on the three-colored fluorescent powder since the aging characteristics of different fluorescent material are different.
According to an aspect, a method for generating white light is provided, which comprises exciting a blue cathodoluminescence material by a field emission device (FED) to generate a blue light, exciting a yellow photoluminescence material by the generated blue light to generate a yellow light and complexing residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The field emission device is specifically a blue-light field emission device; the blue light generated by the excitation of the blue-light field emission device on the blue cathodoluminescence material exhibits a spectrum peak at a wavelength ranging from 420 nm to 490 nm.
The blue cathodoluminescence material is selected from a group consisting of Y2SiO5:Ce, SrGa2S4:Ce, ZnS:Ag, ZnS:Tm, Sr2CeO4, ZnS:Zn and AlN:Eu;
Or La(1-x)Ga(1-y)AlyO3:xTm; wherein a range of x is 0<x≦0.1 and a range of y is 0≦y≦1;
Or the La(1-x)Ga(1-y)AlyO3:xTm in which the La is partly or completely substituted by Y, Gd, Lu or Sc; wherein the range of x is 0<x≦0.1 and the range of y is 0≦y≦1.
The yellow photoluminescence material is preferably rare earth garnet fluorescent powder taking Ce as an activator.
The rare earth garnet fluorescent powder taking Ce as the activator is preferably RE3(Al1-xGax)5O12:Ce; wherein a range of x is 0≦x≦1 and RE is selected from a group consisting of at least one of Y, Tb, Gd, Lu and La.
According to an aspect, a lighting device for generating white light is provided, which comprises a cathode plate component, an anode plate component interval-placed opposite to the cathode plate component and a supporting body connecting the both components together hermetically; the anode plate component comprises a transparent substrate provided with a layer of yellow photoluminescence material, on a lower surface of the transparent substrate a transparent anode and a layer of blue cathodoluminescence material are arranged in turn from top to bottom, or on the lower surface of the transparent substrate a layer of blue cathodoluminescence material and a metal anode are arranged in turn from top to bottom.
The layer of yellow photoluminescence material is specifically a transparent epoxy layer dispersed with the yellow photoluminescence material.
The layer of yellow photoluminescence material is attached to an upper surface of the transparent substrate or interval-placed above the transparent substrate.
The layer of yellow photoluminescence material is made from rare earth garnet fluorescent powder taking Ce as an activator.
The rare earth garnet fluorescent powder taking Ce as the activator is RE3(Al1-xGax)5O12:Ce; wherein a range of x is 0≦x≦1 and RE is at least one of Y, Tb, Gd, Lu and La.
The layer of blue cathodoluminescence material is a layer of blue cathodoluminescence material generating a blue light exhibits a spectrum peak at a wavelength ranging from 420 nm to 490 nm when excited by the cathode ray.
The layer of blue cathodoluminescence material is made from Y2SiO5:Ce, SrGa2S4:Ce, ZnS:Ag, ZnS:Tm, Sr2CeO4, ZnS:Zn or AlN:Eu;
and La(1-x)Ga(1-y)AlyO3:xTm; wherein a range of x is 0<x≦0.1 and a range of y is 0≦y≦1;
and the La(1-x)Ga(1-y)AlyO3:xTm in which the La is partly or completely substituted by Y, Gd, Lu or Sc; wherein the range of x is 0<x≦0.1 and the range of y is 0≦y≦1.
Among them, Y2SiO5:Ce means the luminescent material Y2SiO5 which takes Ce as the activator and the meanings of the remaining SrGa2S4:Ce, ZnS:Ag, ZnS: Tm, ZnS:Zn and AlN:Eu are the same. La(1-x)Ga(1-y)AlyO3:xTm means the luminescent material La(1-x)Ga(1-y)AlyO3 which takes Tm as the activator.
A brand-new method is utilized to realize the white light generation of field emission device in the present invention, that is exciting a blue cathodoluminescence material by a field emission device (FED) to generate a blue light, exciting a yellow photoluminescence material by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the yellow light to generate a white light. Since only one kind of blue cathodoluminescence material is directly irradiated by the electron beam in the field emission device of the present invention, the overall aging characteristic of the device basically depends on the aging characteristics of this material. Therefore, the aging problem of the light source device can be reduced effectively if only one kind of blue cathodoluminescence material with preferred stability is selected and utilized. The probability that the color coordinate deviates and the light source efficiency declines can be reduced significantly thereby on condition that the light source device has been used for a long time.
The lighting device for generating white light in the present invention is provided with the anode plate component different from that in the prior art besides the existing cathode plate component. For this anode plate component, an anode and a luminescent layer are arranged on the lower surface of the transparent substrate facing the cathode plate. The luminescent layer is a layer of blue cathodoluminescence material. When excited by the electron beam, the luminescent layer just emits a blue light with a spectrum peak of 420-490 nm Meanwhile, there is also a luminescent layer on the upper surface of the transparent substrate. The luminescent layer is composed of a yellow photoluminescence material capable of emitting a yellow light and absorbing the blue light at 420-490 nm. The blue light passes through the transparent substrate and then illuminates the layer of yellow photoluminescence material, a yellow light with a spectrum peak of 540-590 nm is emitted afterwards. A white light is then formed by complexing the residual blue light and the emitted yellow light. For this lighting device, by changing the structure and constitution of the luminescent layer of the anode plate module of traditional field emission light source and only selecting one kind of blue cathodoluminescence material with preferred stability to form the luminescent layer, the aging problem of field emission device can be reduced effectively. Accordingly, the device can be used for a long time and the probability that the color coordinate deviates and the light source efficiency declines is reduced. The device in the present invention can be applied on the large scale and high power lighting easily.
According to the requirement on the wavelength range of the luminescence of the blue cathodoluminescence material in the present invention, the blue cathodoluminescence material suitable for the present invention comprises Y2SiO5:Ce, SrGa2S4:Ce, Sr2CeO4, ZnS:Ag, ZnS:Tm, ZnS:Zn, AlN:Eu and La(1-x)Ga(1-y)AlyO3:xTm (wherein the range of x is 0<x≦0.1 and the range of y is 0≦y≦1; besides, La can be partly or completely substituted by Y, Gd, Lu and Sc) etc. This kind of material possesses better luminescence property when excited by the cathode ray.
In the present invention, the yellow photoluminescence material is selected to be the rare earth garnet fluorescent powder taking Ce as the activator, which fits the formula RE3(Al1-xGax)5O12:Ce; wherein the range of x is 0≦x≦1 and the rare earth element RE can be chosen from at least one of Y, Tb, Gd, Lu and La. In particular, when RE=Y or Tb, the yellow photoluminescence material is YAG:Ce and TAG:Ce, respectively. This kind of material can absorb the blue light at about 450 nm and emit the yellow light in the range of 540-590 nm effectively.
The yellow photoluminescence material can be dispersed in the transparent epoxy directly and spread onto the outside surface of the glass substrate directly to form the layer of yellow photoluminescence material. Its preparation is simple and convenient.
The present invention will be further described with reference to the accompanying drawings and embodiments in the following. In the Figures:
The test conditions applied for the cathodoluminescence spectrogram are as follows: the excitation voltage is 5 kV and the beam current is 8 μA.
SHIMADZU RF-5301 fluorescence spectrograph is used for the measurement of the excitation and emission spectrum.
The present invention will be further described by the usage of the embodiments and accompanying drawings in the following.
The raw materials in the embodiments can be bought from a common market and can be used immediately.
The method comprises exciting a blue cathodoluminescence material Y2SiO5:Ce (the commercial product produced by RIYA chemical industry joint-stock company is utilized) by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Y3(Al0.8Ga0.2)5O12 taking Ce as the activator by use of the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The method comprises exciting a blue cathodoluminescence material SrGa2S4:Ce by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Tb3 (Al0.6Ga0.4)5O12 taking Ce as the activator by use of the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The method comprises exciting a blue cathodoluminescence material ZnS:Ag (the product produced by Shanxi rainbow fluorescent material LTD is utilized) by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Y3Al5O12 (the product produced by Dalian LUMING lighting technology LTD is utilized) taking Ce as the activator by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light. As shown in
The method comprises exciting a blue cathodoluminescence material AlN:Eu by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Gd3Ga5O12 taking Ce as the activator by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The method comprises exciting a blue cathodoluminescence material ZnS:Zn by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material (Y0.9,Gd0.1)3(Al0.8Ga0.2)5O12 taking Ce as the activator by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The method comprises exciting a blue cathodoluminescence material ZnS:Tm by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Y3Ga5O12 taking Ce as the activator by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The method comprises exciting a blue cathodoluminescence material La0.99GaO3:0.01Tm by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Y3Al5O12 taking Ce as the activator (the product produced by Dalian LUMING lighting technology LTD is utilized) by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light. As shown in
The method comprises exciting a blue cathodoluminescence material La0.99AlO3: 0.01Tm by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Lu3Ga5O12 taking Ce as the activator by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The method comprises exciting a blue cathodoluminescence material La0.99(Ga0.8Al0.2)O3: 0.01Tm by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material La3Ga5O12 taking Ce as the activator by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The method comprises exciting a blue cathodoluminescence material Y0.98(Ga0.8Al0.2)O3:0.02Tm by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Y3Al5O12 taking Ce as the activator by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The method comprises exciting a blue cathodoluminescence material Sc0.99(Ga0.8Al0.2)O3: 0.01Tm by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Y3Al5O12 taking Ce as the activator by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The method comprises exciting a blue cathodoluminescence material Lu0.99(Ga0.7Al0.3)O3: 0.01Tm by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Y3Al5O12 taking Ce as the activator by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
The method comprises exciting a blue cathodoluminescence material Sr2CeO4 by the blue-light field emission device to generate a blue light at 420-490 nm, exciting a yellow photoluminescence material Y3Al5O12 taking Ce as the activator by the generated blue light to generate a yellow light and complexing the residual blue light that do not excite the yellow photoluminescence material and the generated yellow light to generate a white light.
As shown in
As shown in
The anode plate component 4 comprises a transparent substrate 403 and a layer of blue cathodoluminescence material 402 formed on the transparent substrate 403 (ZnS:Ag is selected as the blue material). A layer of metal aluminum is vapor-plated on the layer of blue cathodoluminescence material 402 as the metal anode 401. A layer of yellow photoluminescence material 404 (YAG:Ce is selected as the yellow photoluminescence material) is arranged above the transparent substrate 403. The layer of yellow photoluminescence material 404 is a transparent epoxy layer dispersed with the yellow photoluminescence material. A vacuum space is formed since there is certain space between the layer of yellow photoluminescence material 404 and the transparent substrate 403. The coating of the layer of blue cathodoluminescence material 402 is the same as that in the example 14.
LaGaO3:Tm, Y2SiO5:Ce, SrGa2S4:Ce, ZnS:Ag, ZnS:Tm, Sr2CeO4, ZnS:Zn, AlN:Eu; La0.99Ga0.5Al0.5O3:0.01Tm, La0.9GaO3:0.1Tm, La0.98AlO3:0.02Tm, La0.92Ga0.6Al0.4O3:0.08Tm, La0.6Y0.33Ga0.4Al0.6O3:0.07Tm, Gd096Ga0.35Al0.65O3:0.04Tm, La0.2Lu0.75Ga0.8Al0.2O3:0.05Tm etc. can also be selected as the blue fluorescent material.
Y3Al5O12:Ce, Tb3Al5O12:Ce, Gd3Al5O12:Ce, Lu3Al5O12:Ce, La3Al5O12:Ce, Y3Ga5O12:Ce, Y3(Al0.9, Ga0.1)5O12:Ce, Y3(Al0.5, Ga0.5)5O12:Ce, Y3(Al0.1, Ga0.9)5O12:Ce, Y3(Al0.9, Ga0.1)5O12:Ce, Gd0.1)3(Al0.9, Ga0.1)5O12:Ce, (Y0.5, Gd0.5)3(Al0.9Ga0.1)5O12:Ce, (Y0.1, Gd0.9)3(Al0.9, Ga0.1)5O12:Ce etc. can also be selected as the yellow photoluminescence material.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CN09/70708 | 3/10/2009 | WO | 00 | 9/9/2011 |
