CN100547815C - White LED, backlight and LCD - Google Patents

Abstract

The invention provides a kind of White LED, it comprises: ultraviolet emission diode or purple light emitting diode, with the fluorophor that comprises three kinds of visible lights at least that is used to launch blue light, green light and red light, wherein the emission spectrum of this White LED has: first glow peak in wavelength is the blue light district of 440-460nm, second glow peak in wavelength is the green light district of 510-530nm and the 3rd glow peak in wavelength is the red light district of 620-640nm.And preferably the half-peak breadth of each luminescence peak is 50nm or littler.Therefore, can provide a kind of White LED, backlight and LCD, described LCD is used this White LED, and shows high brightness and excellent color reproduction performance.

Description

White LED, backlight and LCD

Technical field

The present invention relates to a kind of White LED (light-emitting diode), a kind of backlight and a kind of LCD of using described White LED, this White LED is applicable to described backlight liquid crystal display.More specifically, the present invention relates to a kind of White LED, a kind of backlight and a kind of LCD of using described White LED, because described White LED is with respect to blue, green and the less emission light of sneaking into other color of red light, thereby demonstrate high brightness and excellent color reproduction performance.

Background technology

Light-emitting diode (LED) is to be used for luminous semiconductor diode, and has the function that converts electrical energy into ultraviolet light or visible light.Especially, in order to utilize visible light, a kind of luminescence chip that is formed by luminescent material is widely used by the LED that transparent resin is sealed in wherein, and described luminescent material is GaP, GaAsP, GaAlAs, GaN, InGaAlP or analog for example.In addition, display type LED also is widely used, and in described display type LED, luminescent material is installed on the upper surface of printed circuit board (PCB) or plain conductor, and the material that is mounted is formed as the resin-case sealing of numerical chracter or letter shapes.

In addition, be comprised in the front of luminescence chip or in the resin time, also may suitably control glow color when various phosphoruses.That is to say that LED can reproduce the various light of the visible region from indigo plant to red scope, this is suitable for concrete the application.And, because light-emitting diode (LED) is semiconductor element, so LED has long life and height reliability, to such an extent as to LED during as light source, the replacing frequency of the LED that is caused by fault is effectively reduced.Therefore, LED is used as the part of following various devices widely: mobile communications device, PC external equipment, OA (office automation) device, household electrical appliance, audio-visual equipment, various switch, various display unit are as being used for light source display panel or analog backlight.

But, in recent years, use the user's of above-mentioned various display unit color sense to improve greatly, to such an extent as to a kind of function that can reproduce meticulous color shade of technical needs, and have the LED outward appearance of high resolution and homogeneous.Especially, the LED of emission white light is more and more used and is popularized as the illuminating lamp backlight or automobile-used of portable phone, and increases greatly as the demand of the good substitute of fluorescent lamp for LED.Consider these,, attempted carrying out various improvement in order to realize the color rendering that white light is high and the LED outward appearance of homogeneous.

Up to now, LED for emission white light normally used or that try out, there are two types: in conjunction with blue LED (blue emission diode) and yellow luminescent phosphor (YAG) (if use needs, also can be red-emitting phosphors) and the LED (hereinafter being called " Class1 ") of formation; And the LED (hereinafter being called " type 2 ") that forms in conjunction with the diode of emission ultraviolet ray or ultraviolet light and blue, yellow, red light-emitting phosphor.In present stage, because Class1 has the brightness higher than type 2, so Class1 has obtained using the most widely.

But Class1 demonstrates following shortcoming.That is, see radiative direction according to the user, emission light is regarded as little sodium yellow by the user easily, and when emission light projected on the white surface, sodium yellow and blue light presented inhomogeneities on white surface.Therefore, having a kind of situation is exactly that the light of the White LED emission of Class1 is called as " pseudo-white light ".

When white light being estimated by the average color rendering index of indication white light quality, the low scope of (70 or more 75 or still less) that the average color rendering index of the white light LEDs of Class1 maintains 70 to 75.

On the other hand, before though a kind of white light LEDs in back (type 2) is inferior on luminosity a kind of (Class1), but inhomogeneities of its emission light and projection light is lacked than Class1, to such an extent as to the LED of type 2 consolidated its be used to throw light on and light source purposes backlight on the leading position.The LED expection of type 2 will be promoted widely, and begin further deeply development.

The improved example that carries out on the developing direction of expectation is, reported a kind of white luminous LED that forms with the lower part by combination: ultra-violet light-emitting LED, europium excites halophosphates fluorophor or europium to excite chlorate MClO 3 fluorescent substance, copper, aluminium excite zinc sulphide fluorophor or europium, manganese to excite chlorate MClO 3 fluorescent substance as the green emitting fluorophor, excite yttrium oxysulfide (yittrium oxysulfide) fluorophor as red light-emitting phosphor (for example, consulting non-patent document 1) with europium.

As improved another example, also reported a kind of white luminous LED that forms with the lower part by combination: ultra-violet light-emitting LED, europium excites halophosphates fluorophor or europium to excite chlorate MClO 3 fluorescent substance, and europium, manganese excite chlorate MClO 3 fluorescent substance as the green emitting fluorophor; Excite sulphur lanthana fluorophor as red light-emitting phosphor (for example, consulting patent document 1) with europium.

Though these white luminous LED have high color rendering and radiative high homogeneity, these characteristics all are the inherent characteristics of the White LED of type 2, and it is not enough that brightness remains, and need further to improve.According to inventor's of the present invention understanding,, must in white spectrum, satisfy following requirement in order in the white luminous LED of the above-mentioned type 2, to reach high-color rendering and high brightness simultaneously.Clear and definite says, incident light with 450nm, 560nm and 620nm wavelength is comprised in the white-light spectrum in a kind of well-balanced mode, the corresponding peaks that has human color sensitivity at above-mentioned wavelength place, and the luminous efficiency of the corresponding fluorophor of blue light (B), green glow (G) and ruddiness (R) earth complex luminescent component obtains good balance.

On the other hand, utilize above-mentioned White LED (white light-emitting diode) to be widely used as component parts: mobile communications device such as portable phone, mobile phone or analog with lower device as LCD backlight, OA (office automation) device is as PC or analog, household electrical appliance, audio-visual equipment, various switch, various display unit are as being used for light source display panel or analog backlight.

These conventional LCD form by backlight the combination with colored filter that will utilize cold-cathode fluorescence lamp (CCFL), and are improved, thereby reach about about 70% color reproduction scope based on international standard ratio (NTSC ratio).But, still need further raising for the color reproduction scope.In addition owing to contain harmful mercury as the cold-cathode fluorescence lamp of light source, use mercury for the adverse effect of environment by serious pointing out.

In addition, in recent years, blue led (B-LED) and the developed and commercialization of LED that can send ultraviolet light, and LED lighting apparatus (lighting apparatus) is in positive development.Existing three types LED lighting apparatus: by the LED lighting apparatus (Class1) that forms in conjunction with B-LED (blue LED) and yellow luminescent phosphor; The LED lighting apparatus (type 3) that the corresponding light of being launched by R-LED (red light emitting diodes), G-LED (green LED) and B-LED (blue LED) by mixing forms; By the LED lighting apparatus (type 2) that UV-LED (ultraviolet emitting diode) and RGB fluorophor are combined and form.

The shortcoming that the LED lighting apparatus of Class1 and type 3 has makes colorrendering quality difference and light color control difficulty.So, realize that the expectation of lighting apparatus of the type 2 is made up of the UV-LED+RGB fluorophor is just more urgent.

But even will be applied to back light by the White LED that the UV-LED+RGB fluorophor is formed, the color reproduction scope also is not enough.For example, when patent document 1 disclosed White LED is applied to LCD, green light rather than blue light are sneaked in the spectrum of the light that penetrates blue color filter, and blue light is sneaked in the spectrum of light of penetration green filter.As a result, the problem of appearance makes colorrendering quality by disadvantageous reduction.

Patent document 1: Japanese patent application (disclosing) 2000-73052.

Non-patent document 1:Technical Journal of Mitsubishi Densen Kogyo (published July2002, No.99).

Summary of the invention

According to inventor's of the present invention understanding, obtained following discovery from a series of development histories of the conventional white LED that is used for realizing type 2.That is, clear and definite be the White LED that is used for lighting apparatus be used for existing different developing direction between the White LED backlight.That is to say, be used for the White LED of lighting apparatus, realize that the high average color rendering index (Ra) of high brightness and decision white light quality is crucial.On the contrary, be used for White LED backlight, high brightness and wide color reproduction scope all are essential technically.In other words, though high brightness is lighting apparatus and the common property that all needs backlight, according to the concrete needs of related device, high average color rendering index is different with wide color reproduction scope, and always not compatible each other.

Especially these years, the White LED in the LCD TV in the market that is used for having quick growth problem of environmental pollution can not occur, and described environmental pollution is serious problems in the conventional cold light cathode ray tube.In addition, the possibility that enlarges the color reproduction scope is also arranged, thereby be able to great raising for the expectation of technical development.

In these cases, in the evolution of the White LED of the type 2 that forms combining with three kinds or more VISIBLE LIGHT EMISSION fluorophor by ultraviolet emitting diode or purple light emitting diode, the present inventor has had been found that and has been applicable to the desirable luminescent spectrum of white led lamps as LCD backlight, and found the combination of the fluorophor of realizing this luminescent spectrum.The present invention is found to be the basis and realizes with above-mentioned.

In addition, with the White LED of routine as under the situation of backlight liquid crystal display, White LED and colored filter are inconsistent, to such an extent as to thereby other light can sneak into and make the colorrendering quality deterioration in the corresponding rgb light.This is also to be used for highway traffic sign or similar aspect because conventional White LED not only is widely used for backlight liquid crystal display, so that engineers only has been placed on attentiveness on the emission white light.

As the result that inventor of the present invention actively studies, the present inventor has been found that the compatibility (compatibility) between the wavelength of transmitted light of RGB colored filter and White LED is very important, and the present invention is achieved on the basis of above-mentioned discovery.

The present invention has been achieved with the problem that solves above-mentioned routine, and the invention provides a kind of White LED, the fluorophor that it comprises ultraviolet emission diode or purple light emitting diode and is used to launch at least three kinds of visible lights that comprise blue light, green glow and ruddiness; Wherein the spectrum of White LED has first glow peak in wavelength is the blue light region of 440-460nm, in wavelength is the green Region of 510-530nm second glow peak is arranged, and in wavelength is the red light district of 620-640nm the 3rd glow peak is arranged.

In addition, in above-mentioned White LED, preferably first to the 3rd glow peak in blue, green and red light district each all have 50nm or littler half-peak breadth (FWHM :) in the full duration of peak one half.

In addition, in above-mentioned White LED, also the fluorophor of preferred emission blue light is the halophosphate fluorophor that europium excites, and it is represented by general formula 1: (Sr _1-x-yBa _xCa _yEu _z) ₁₀(PO ₄) Cl ₂, wherein x, y, z satisfy following relation respectively: x＜0.2, y＜0.1, and 0.005＜z＜0.1.

And in above-mentioned White LED, the fluorophor of preferred emission green glow is the chlorate MClO 3 fluorescent substance that europium and manganese excite, and it is represented by general formula 2: (Ba _1-x-y-zSr _xCa _yEu _z) (Mg _1-uMn _u) Al ₁₀O ₁₇, wherein x, y, z, u satisfy following relation respectively: x＜0.5, y＜0.1,0.15＜z＜0.4 and 0.3＜u＜0.6.

In addition, in above-mentioned White LED, the fluorophor of preferred emission ruddiness is the sulphur lanthana fluorophor that europium excites, and it is represented by general formula 3: (La _1-x-yEu _xM _y) ₂O ₂S, wherein M is the element of at least a Sb of being selected from and Sn, and x, y satisfy following relation respectively: 0.01＜x＜0.15 and y＜0.03.

And in above-mentioned White LED, the luminous intensity of preferred ultraviolet emission diode or purple light emitting diode has peak value in the 360-410nm wave-length coverage.

In addition, White LED of the present invention is applicable to LCD backlight and the above-mentioned White LED of use.That is, of the present inventionly backlightly be characterised in that it comprises above-mentioned White LED.

And, the spectrum of preferred above-mentioned White LED has first glow peak in wavelength is the blue light region of 440-450nm, with be to have second glow peak in the green Region of 510-530nm at wavelength, wherein each all has 50nm or littler half-peak breadth at first to second glow peak of blue light and green Region.

And, LCD of the present invention comprises above-mentioned White LED, use the backlight of this White LED and be used to filter the colored filter of indigo plant, green, red light, the spectrum area of forming by the light component penetration green filter and that have the 400-500nm wavelength wherein, the percentage of the spectrum area of forming with respect to the light component that by wavelength is 400-600nm is 15% or littler; And, be the spectrum area that the light component of 400-550nm is formed by wavelength, the percentage of the spectrum area of forming with respect to the light component that by wavelength is 400-600nm is 90% or bigger.

In addition, in above-mentioned LCD, the wavelength of transmitted light that preferably is used in the light-emitting diode in the White LED is 360-410nm.

And in above-mentioned LCD, the spectrum that preferably penetrates blue color filter is included in first summit of 440-450nm wave-length coverage existence and second summit that exists in the 510-530nm wave-length coverage; And the height of second summit be the first peak heights of roofs 1/2 or still less.

In addition, in above-mentioned LCD, preferably: when transmission peak wavelength is the light time of 500nm, the transmission coefficient (transmissivity) at the blue color filter place be the max transmissive coefficient 90% or littler, the transmission coefficient at the green color filter place be the max transmissive coefficient 95% or littler; And when transmission peak wavelength is the light time of 600nm, the transmission coefficient at the green color filter place be the max transmissive coefficient 40% or littler.

White LED of the present invention demonstrates high brightness and excellent colorrendering quality.And, according to LCD of the present invention, owing to use the backlight spectra of White LED and the transmitted spectrum of colored filter to be controlled suitably, so LCD is extraordinary aspect colorrendering quality.So, use the backlight and LCD of all of White LED of the present invention can demonstrate high brightness and excellent colorrendering quality.In addition, different with the cold-cathode fluorescence lamp (CCFL) of routine is do not need here to use harmful mercury, thereby problem of environment pollution caused can not take place.

Description of drawings

Fig. 1 is the schematic sectional view according to the structure of an embodiment of White LED of the present invention.

Fig. 2 is the schematic diagram according to an embodiment of the emission spectrum of White LED of the present invention.

Fig. 3 compares as LCD backlight with existing C CFL, with the schematic diagram of White LED of the present invention as the color reproduction scope under the situation of LCD backlight.

When the half-peak breadth of Fig. 4 emission spectrum in White LED of the present invention changes, the schematic diagram of an embodiment of emission spectrum.

Fig. 5 is when the White LED that has emission spectrum shown in Figure 4 respectively is used as corresponding liquid crystal display backlight, the schematic diagram of color reproduction scope.

Fig. 6 is the diagram of an embodiment of spectrum that penetrates the light of the colored filter that is used for LCD of the present invention.

Fig. 7 is the diagram of an embodiment of spectrum that penetrates the light of the colored filter that is used for LCD of the present invention.

Fig. 8 is the schematic diagram that is used in the emission spectrum of the White LED in the LCD of Comparative Examples 5.

Fig. 9 is the diagram of spectrum that penetrates the light of the colored filter in the LCD of Comparative Examples 5.

Preferred implementation

Fig. 1 is the schematic sectional view according to an execution mode of White LED of the present invention.White LED shown in Figure 1 comprises light-emitting diode a, imbed luminescent coating b in the resin, be used to reflect and guide the reflector c from the light of above-mentioned light-emitting diode a and luminescent coating b emission to the external world and be used to support the resinous framework d of luminous component.This White LED has a mechanism, the electric energy that wherein is applied on the LED lamp is changed into ultraviolet light or purple light by light-emitting diode a, and the luminescent coating b that the described light that is converted is positioned at the top of Light-Emitting Diode a further is converted to has more long wavelength's light respectively, thereby the white light that totally presents emits to the outside of LED lamp.

As ultraviolet light-emitting diode or purple LED, various light-emitting diodes such as InGaN type, GaN type, AlGaN type diode or analog can be used.Especially, at the light-emitting diode that uses in the wave-length coverage of luminescence peak at 360-420nm, and, just might design the White LED of the color reproduction performance that manifests high brightness and excellence with under this light-emitting diode and the situation that hereinafter described fluorophor combines.

As the fluorophor that is used for above-mentioned luminescent coating b, importantly adopt the VISIBLE LIGHT EMISSION fluorophor to be used to radiate to comprise at least three kinds of light of blueness, green and red light.Specifically, here the fluorophor of using, its spectrum comprises three glow peaks, that is, and and first glow peak in wavelength is the blue light region of 440-460nm, second glow peak in wavelength is the green Region of 510-530nm, the 3rd glow peak in wavelength is the red light district of 620-640nm.

In other words, during as the red light-emitting phosphor of 620-640nm, three kinds of VISIBLE LIGHT EMISSION fluorophor just have been to use as the green emitting fluorophor of 510-530nm, spike length when the blue-light-emitting fluorescent material that uses spike length as 440-460nm, spike length.In this connection, when the light time of having used two or more fluorophor emission same colors, it should be three kinds or more that the kind of VISIBLE LIGHT EMISSION fluorophor amounts to.

For example, if White LED shown in Figure 1, the electric energy that is applied to light-emitting diode a is converted into ultraviolet light (or purple light) by light-emitting diode a, and the light that is transformed further is converted into by the luminescent coating b on light-emitting diode a top has more long wavelength's light respectively, thereby the white that totally presents is emitted to outside the LED.

In this, in the present invention, ultraviolet light-emitting diode or purple light emitting diode are called as " light-emitting diode ", and are called as " White LED " as the white light emitting diode of finished product.

Fig. 2 is as shown in Figure 1 the schematic diagram of an embodiment of emission spectrum of White LED according to the present invention.Particularly, Fig. 2 has represented the emission spectrum when following situation: thus light-emitting diode is excited by the current value of 20mA and radiates the ultraviolet ray of peak value at 400nm wavelength place, should ultraviolet ray be converted into the white light of colourity for (0.253,0.238) by fluorophor then.This emission spectrum is characterised in that peak value is detected at the 447nm wavelength place of blue light region (B), the 518nm wavelength place of green Region (G) and the 623nm wavelength place in the red light district (R), and the half-peak breadth of respective peaks is 50nm or littler.

Fig. 3 is a curve chart, and the emission color that wherein penetrates the light of common indigo plant, green and Red lightscreening plate is plotted in the XYZ chromaticity diagram.That is to say that from the corresponding colored filter transmission of light warp that White LED according to the present invention sends, described colored filter is generally used for LCD (LCD device).The corresponding emission color of transmitted light is plotted in the XYZ chromaticity diagram.

According to this XYZ chromaticity diagram, LCD is intended to demonstrate colourity and is in by blue (B), green (G) and redness (R) these three launch points and links to each other and light in the Delta Region that forms.

That is to say that when the Delta Region in above-mentioned XYZ chromaticity diagram was wideer, LCD just can show the light with various colourities more.So, just we can say that LCD (LCD) has wide color reproduction scope, and LCD has excellent color reproduction performance.

In Fig. 3, use the color reproduction scope of the LCD of conventional cold-cathode fluorescence lamp (CCFL) also to indicate with thick dashed line.But what can be easy to determine be, LCD of the present invention is obviously than the color reproduction wide ranges of conventional LCD, thereby LCD of the present invention can have excellent color reproduction performance certainly.

In Fig. 3, also with dashed lines marks the international standard (NTSC) that shows desirable triangle color reproduction scope simultaneously.The degree of color reproduction scope is represented as a relative value usually, and this relative value is to be set at 100 o'clock in the trigonum that NTSC is represented, obtains by the trigonum area in the calculating chromatic diagram.On the basis of this definition, the color reproduction scope of LCD of the present invention is 98, and conventional LCD is 65.

As indicated above, preferably in the luminescent spectrum of White LED, the half-peak breadth of blue light region, green Region and red light district corresponding peaks is 50nm or littler.For example, by in conjunction with B, the G of appointment of the present invention, White LED that the R fluorophor obtains, the half-peak breadth that has prepared the half-peak breadth of B, G, R color of light peak value wherein and all be 50nm or littler White LED (product 1) and wherein a part of B, G, R color of light peak value surpasses the White LED (product 2) of 50nm.Fig. 4 is the comparison diagram of luminescent spectrum in the White LED of product 1 and 2.And Fig. 5 is to use the curve chart according to the color reproduction scope of the LCD of the White LED of product 1 and 2.

By the result among Fig. 4 and Fig. 5 can be clear and definite be that according to NTSC standard shown in Figure 3, the color reproduction scope of the LCD of product 1 is 98, and product 2 is 87.Though the color reproduction scope of product 2 is better than cold-cathode fluorescence lamp, the color reproduction scope of product 2 will be inferior to product 1.Reason is, though the spectrum of product 2 has peak value at the 518nm wavelength place of the 447nm of the blue light region of appointment of the present invention wavelength place, green Region, the 623nm wavelength place of red light district, but the wide 60nm that reaches of the half-peak breadth at blue peak, thereby the purity of blue light component is worsened.

In this connection, most preferably all corresponding peaks are 50nm or littler.But if the maximum of half-peak breadth is 80nm or littler, such width is suitable for practical application.Especially, if blue, green or and red light in to have only one peak value half-peak breadth be 80nm and the half-peak breadth that remains two kinds of color peaks is 50nm or littler, the color reproduction scope can reach 80 or bigger with respect to NTSC.Thereby the half-peak breadth at each peak preferably sets at 80nm or littler, more preferably 50nm or littler.

As indicated above, when use be included in wavelength as the glow peak in the blue light region of 440-460nm, at wavelength as the glow peak in the green Region of 510-530nm with at wavelength during as the fluorophor of the glow peak in the red light district of 620-640nm, and the half-peak breadth of corresponding glow peak is 70nm or littler, preferred 50nm or more hour, just can form the White LED of the color reproduction performance with high brightness and excellence.

Next, will make an explanation to fluorophor.About comprising the fluorophor of above-mentioned feature, its composition is had no particular limits.But the preferred example of fluorophor can be listed hereinafter.

Fluorophor as the emission blue light can list the halophosphate fluorophor that europium excites, and it is represented by general formula 1: (Sr _1-x-yBa _xCa _yEu _z) ₁₀(PO ₄) Cl ₂, wherein x, y, z satisfy following relation respectively: x＜0.2, y＜0.1, and 0.005＜z＜0.1.In above-mentioned general formula 1, x value and y value can comprise 0.As mentioned below, sharp-pointed for the shape that makes glow peak, preferably x value and y value were set near 0 (comprising 0).

And, as the fluorophor of transmitting green light, can list the chlorate MClO 3 fluorescent substance that europium and manganese excite, it is represented by general formula 2: (Ba _1-x-y-zSr _xCa _yEu _z) (Mg _1-uMn _u) Al ₁₀O ₁₇, wherein x, y, z, u satisfy following relation respectively: x＜0.5, y＜0.1,0.15＜z＜0.4 and 0.3＜u＜0.6.In above-mentioned general formula 2, x value and y value can comprise 0.

In addition, the fluorophor as the emission red light can list the sulphur lanthana fluorophor that europium excites, and it is represented by general formula 3: (La _1-x-yEu _xM _y) ₂O ₂S, wherein M is the element of at least a Sb of being selected from and Sn, and x, y satisfy following relation respectively: 0.01＜x＜0.15 and y＜0.03.In above-mentioned general formula 3, x value and y value can comprise 0.

Though the mean grain size to fluorophor has no particular limits,, the mean grain size of fluorophor preferably sets at 3 μ m or bigger.Being large enough to when the mean grain size of fluorophor is 3 μ m or when bigger, just can obtain high brightness capabilities easily.The upper limit to the mean grain size of fluorophor has no particular limits.But, should suitably decide the upper limit to meet the structure of White LED.But if the mean grain size of fluorophor is excessive, fluorophor just is not easy to be mixed equably.So the upper limit of fluorophor mean grain size preferably sets at 60 μ m or littler.

And the mixing ratio of each fluorophor is arbitrarily, as long as this mixing ratio can realize the target colourity of gained light.But, generally, for the White LED that obtains, preferably mix the blue light fluorophor of 15-25 quality % and the green glow fluorophor of 15-25 quality %, surplus is a red line emitting phosphors, is comprising of 100 quality % of mixture blue, green, red line emitting phosphors thereby obtain total amount.

The method of making the luminescent coating in the White LED has no particular limits.But, for example, can adopt a kind of method that may further comprise the steps: every kind of fluorophor powder is mixed with appropriate resin to prepare the mixture of some kinds; Comprise the final phosphor blends of described fluorophor and resin with preparation with the mixture that mixes these kinds.In addition, can also adopt a kind of method that comprises the steps: mix every kind and be used to launch the fluorophor powder of respective color light with the preparation phosphor blends; With with phosphor blends and mixed with resin to prepare the final phosphor blends that comprises described fluorophor and resin.

Zhi Bei phosphor blends is applied on the light-emitting diode like this, and cured resin subsequently, can form White LED thus.

Owing to can keep high brightness and very outstanding aspect the color reproduction performance according to White LED of the present invention, this White LED can be effectively as backlight liquid crystal display used in various display unit, described display unit for example, comprise portable phone and mobile phone mobile communications device, PC external equipment, OA (office automation) device, household electrical appliance, audio-visual equipment, various switch, be used for light source display panel or analog backlight.Use the LCD of this White LED can obtain high brightness capabilities and excellent color reproduction performance.In addition, when this White LED is used as when backlight, it is backlight to form to make up a plurality of White LEDs.For example, can dispose four White LEDs to form rectangular shape.

And, LCD of the present invention can be applied to various drive systems such as simple matrix system, active matrix system, static system or similar system, various liquid crystal such as TN, STN, TSTN or analog, evenly arrive twisted planar pattern (homogeneous-twisted planar mode), RFFMH pattern, vertical orientated configuration pattern (patternedvertical alignment mode), IPS pattern or analogue at various display systems such as ASM pattern, ocb mode.In addition, LCD of the present invention also can be applied to various display systems such as needs LCD backlight, for example, and transmission type lcd device, semi-transmission type liquid crystal display device or analog.

The configuration of LCD mainly comprise be used for to liquid crystal shutter (shutter) part provide light part backlight, be used for the liquid crystal shutter part by the voltage-regulation transmitted intensity that applies and be used for the colored filter part of Show Color.Necessary, other parts for example diffusion disk, lens, polaroid, phase difference film, reflector (reflector plate) or the parts that similarly have functions such as revising optical uniformity, light distribution performance, phase difference also can be provided.And as part backlight, perhaps back side light-source system or sidelight system can adopt.

Inventor's the understanding according to the present invention, confirmable is among above various element, the color reproduction performance of LCD mainly is the character that depends on colored filter part and part backlight.

LCD of the present invention is characterised in that it comprises the colored filter that uses the backlight of White LED and be used to filter indigo plant, green, red light, wherein by the penetration green filter and wavelength be the spectrum area that the light component of 400-500nm is formed, the percentage of the spectrum area of forming with respect to the light component that by wavelength is 400-600nm is 15% or still less; By wavelength is the spectrum area that the light component of 400-550nm is formed, and the percentage of the spectrum area of forming with respect to the light component that by wavelength is 400-600nm is 90% or more.

That is to say, in the present invention, pay special attention to the light of penetration green filter.It the reasons are as follows described.Promptly be that when using three kinds of fluorophor that are used to launch indigo plant, green, red light, the spike length of corresponding light is begun to be presented in the emission spectrum with blue, green, red order by the shortwave district.Because green spike length is between the long and red spike of blue spike is long, therefore green spike length is subjected to the influence of blue light and red light easily.

Therefore, when the spectral shape of penetration green filter is improved, just might weaken the adverse effect of blue light and red light.As a result, the inventor has been found that the LCD that can obtain having excellent colorrendering quality.And when satisfying following the requirement, the present invention has just been realized.

First requirement is, by pass green color filter and wavelength be the spectrum area that the light component of 400-500nm is formed, the percentage of the spectrum area of being formed with respect to the light component that by wavelength is 400-600nm is 15% or still less; About this point, " passing the light of green color filter " meaning is when LCD is opened, is incident upon penetration green filter light afterwards on the described green color filter by the light of radiation backlight.In addition, the spectrum area of being made up of corresponding light component obtains by equation ∫ Ig (λ) d λ calculating, and wherein luminous intensity is Ig (λ).

Particularly, light for the penetration green filter, when measuring spectrum area (area 1) in the 400-500nm wave-length coverage and the spectrum area in the 400-600nm wave-length coverage (area 2), by equation: the area that (area 1/ area 2) * 100 (%) calculate need be 15% or littler than A.Above-mentioned area is set at 15% or littler than A, means that the long integral body of spike of green glow is in the 500-600nm wave-length coverage.According to this feature, other color of light can be subjected to the influence of blue light wavelength hardly, thereby the color reproduction performance can improve.Preferably, above-mentioned area is 10% or littler than A.

Second requirement be, is the spectrum area that the light component of 400-550nm is formed by penetration green filter and wavelength, and the percentage of the spectrum area of being formed with respect to the light component that by wavelength is 400-600nm is 90% or more.

Particularly, the same with foregoing mode, for light by the penetration green filter, when measuring spectrum area (area 3) in the 400-550nm wave-length coverage and the spectrum area in the 400-600nm wave-length coverage (area 4), by equation: the area that (area 3/ area 4) * 100 (%) calculate need be 90% or bigger than B.Above-mentioned area is set at 90% or bigger than B, means that the long integral body of spike of green glow is in the 400-550nm wave-length coverage.According to this feature, other color of light can be subjected to the influence of red light (or sodium yellow) wavelength hardly, thereby the color reproduction performance can improve.Preferably, above-mentioned area is 91% or bigger than B.

In the present invention, if any one of above-mentioned first demand and second demand is met, the color reproduction performance just can improve.But, when first demand and second demand all are met, may weaken the influence of blue light wavelength and red light (or sodium yellow) wavelength effectively, be preferred feature therefore.

When above-mentioned area reduces 1% than A, represent that the NTSC of color reproduction scope increases about 3 times than meeting.On the other hand, when above-mentioned area increases 1% than B, NTSC is than increasing about 6 times.When present cold-cathode fluorescence lamp was used as light source, the NTSC ratio was about about 70.So confirmable is that the suitable above-mentioned area ratio of control is very effective in order to widen the color reproduction scope.

And the spectrum that preferably penetrates blue color filter comprises and appears at the first peak in the 440-450nm wave-length coverage and appear at second peak in the 510-530nm wave-length coverage, and the height at second peak (b2) be first peak height (b1) 1/2 or littler.In this connection, " penetrating the light of blue color filter " meaning is when LCD is opened, and is incident upon by the light that sends backlight and penetrates blue color filter light afterwards on the blue color filter.

In penetrating the light of blue color filter, second peak height (b2) is 1/2 or littler to the ratio (b2/b1) of first peak height (b1), and its meaning is that when showing blue light, blue light can be subjected to the influence of green light wavelength hardly.That is to say that blue light is purified comprising the green light component of less amount, thereby the color reproduction performance can improve.Second peak height (b2) preferably sets 1/3 or littler the ratio (b2/b1) of first peak height (b1).

In addition, when wavelength is the transmittance of 500nm, the transmission factor (transmissivity) of preferred blue color filter be the max transmissive factor 90% or littler, the transmission factor of green color filter be the max transmissive factor 95% or littler; And when wavelength is the transmittance of 600nm, the transmission factor of preferred green color filter be the max transmissive factor 40% or littler.About this point, the max transmissive factor is defined as, the max transmissive factor when wavelength is the transmittance of 400-700nm.

When wavelength is the transmittance of 500nm the transmission factor of blue color filter be the max transmissive factor 90% or littler, the peak shape of this character representation blue light is sharp-pointed.Similarly, when wavelength is the transmittance of 600nm the transmission factor of green color filter be the max transmissive factor 95% or still less and the transmission factor of green color filter be the max transmissive factor 40% or littler, the peak shape of this character representation green light is sharp-pointed.Sharp-pointed this character representation of peak shape is narrow in the wave-length coverage of blue light and green light mixing.So the light with sharp peak can be subjected to the influence of other color of light hardly, thus the color reproduction performance that is further improved.

According to said structure, just can obtain having the LCD of excellent color reproduction performance.In order to reach above-mentioned feature, must suitably control the compatibility between White LED and the RGB colored filter.For the measure of control colored filter, can adopt various measures here.Particularly, be effective by the measure etc. of selecting pigment that the position of transmissive window or the measure of width, the measure that increases pigment concentration, control colored filter film thickness are set suitably.

The method of producing colored filter is had no particular limits.But, wherein pigment dispersion method is applied to and has crome metal the embodiment of method of black matrix" (matrix) of (Cr) will be described below.

That is to say that this method may further comprise the steps: on the Cr layer that is formed on the glass basis, provide resist layer by spraying process or similar method; Utilize the light exposure technique to form pattern; Carry out corrosion work; At the bottom of peeling off resist layer thereby the fast black base with predetermined structure be provided.

Then, comprise that to cause the photosensitive color resist of multifunctional monomer of catalyst as photoinduction polymeric component and polymerization coated.Subsequently, the colored resist of coating is exposed and utilizes alkaline solution to develop.Each color layer is repeated this a series of operations, thereby form color layer with complete RGB.After this, provide protective layer, and if necessary, also will provide ITO layer and light pad (photo spacer), thereby colored filter just has been produced.

Above-mentioned colored resist is if the photosensitive color resist can be made of following material: multifunctional monomer as photoinduction polymeric component and polymerization cause catalyst, be used for dispersed color equably dispersant, be used to make uniform levelling agent of film thickness and organic solvent, also have colouring agent and adhesive resin.

For above-mentioned colouring agent, can use various colouring agents for example organic pigment, inorganic pigment, dyestuff or analog.But it is preferred having good heat resistance and sunproof colouring agent.For example, can use various pigment for example azo chelate type, condensation azo-type, phthalocyanine type, benzimidazolone type, quinoline a word used for translation ketone type, the peaceful type of iso-indoles (iso-indolynine type), pyransulone type, ature of coal-pyrimidine Type (anthrax-pyrimidine), dibrom-anthansulone type, indanthrone type, franthrone type, perilene Xing, perylene ketone (perinone) type, quino phtharone type, thioindigo type, two puff diene types, anthraquinone type, pyrrolopyrrole (pyrolo-pyrol) type etc.

More specifically, be fit to the pigment of use by following Colour Index (C.I.) number representative.

C.I. yellow uitramarine number: 20,24,83,86,93,109,110,117,125,137,138,139,147,148,150,153,154,166 and 168.

C.I. red pigment number: 9,97,122,123,149,168,177,180,192,208,215,216,217,220,223,224,226,227,228,240 and 254.

C.I. violet pigment number: 19,23,29,30,37,40 and 50.

C.I. blue pigment number: 15,15:1-6,22,60 and 64.

C.I. viridine green number: 7 and 36.

When the kind of controlling above-mentioned pigment, addition and mixing ratio, the transmittance factor can be regulated according to conceivable color.

Mention in passing, when producing colored filter according to pigment dispersion method, be fit to use coloured photoinduction aggretion type resin, it comprises adhesive resin, ethylene type unsaturated compound, photoinduction polymerization initiator and pigment.

As above-mentioned adhesive resin, preferably use water white and have excellent heat resistance and sunproof polymeric material.Particularly; the example of adhesive resin comprises: for example, and epoxy resin, melmac, acrylic resin, polyimide resin, polyamide, mylar, unsaturated polyester resin, polycarbonate resin, light sensitivity monomer and oligomer etc. with (methyl) acryloyl group.

The example of ethylene type unsaturated compound can comprise: for example, monovalence or multivalence monomer are as styrene, (methyl) methyl acrylate, (methyl) ethyl acrylate, (methyl) acrylic acid n-propyl, (methyl) isopropyl acrylate, (methyl) n-butyl acrylate, (methyl) sec-butyl acrylate, (methyl) tert-butyl acrylate, (methyl) isobutyl acrylate, (methyl) acrylic acid n-pentyl ester, methyl styrene, hydroxyethyl, (methyl) acrylate, ethylene glycol, 2-(methyl) acrylate, pentaerythritol acrylate trimethyl etc.; Normal optical induced polymerization type resin is as (methyl) acrylic polyester, (methyl) acroleic acid polyurethane, epoxy (methyl) acrylate or analog.

As photoinduction polymerization initiator (inspiration agent); what can be fit to use has: for example; alpha-aminoacetophenone; anthraquinone; the benzoyl ether; benzil; benzophenone; 4; 4 '-two dimethylamino benzophenone; 4; 4 '-two trichloromethyl benzophenone; the dibutyl Phenylphosphine; α, α '-diethoxy acetophenone; the 2-EAQ; the two phenyl (benzoyl bisphenyl) of benzoyl; the chloro benzophenone; benzoin; benzoin methyl ether; the benzoin isobutyl ether; the anthraquinone thioxanthones; the adjacent benzene benzoic acid (methyl orthobenzoil benzoicacid) of methyl; to dimethylamino benzoylformaldoxime etc.

The White LED production according to of the present invention that has structure shown in Figure 1 by use is backlight.Particularly, White LED is being assembled into when backlight, will arrange in the plane for obtaining the needed a plurality of White LEDs of predetermined surface brightness and luminous flux, thereby four sides that perhaps White LED are disposed at backlight box may obtaining of the present invention backlight.

As indicated above, preferably at the bottom surface or the side cremasteric reflex sheet (reflector) of backlight box.Reflector plate has catoptrical function, and described light is by White LED emission and along the optical surface direction radiation of supporting or opposing of the back side of backlight box and side surface direction.As above-mentioned reflecting piece, operable have: its front surface be processed to minute surface sheet, described minute surface forms by plated metal such as aluminium (AL) or gold (Au); Or the complete molded sheet that forms of the resin with high light reflective properties.

And must control light is uniformly, thereby can not cause any Luminance Distribution on LCD panel.So, can use optical plate and light diffusing patch.Diffusion disk forms light diffusion by providing to the device on the sheet that is made of transparent resin material.In this connection, the device of diffused light also can form by light diffusion material is sneaked in the sheet, perhaps sneak in the sheet and form by the speck matter that will have different reflectivity, perhaps by the sheet surface roughening is formed, perhaps by on the sheet surface, providing the film that constitutes by light diffusion material to form.And, also can suitably use prismatic lens or have the analog that light is converged to the function of particular orientation to replace above-mentioned diffusion disk, perhaps also prismatic lens or analog can be used with diffusion disk.

In the present invention, the emission wavelength that preferably is used in the light-emitting diode in the White LED is 360-410nm.If emission wavelength is 360-410nm, can easily control white light emission spectrum by making up aforesaid fluorophor.The preferred emission wavelength of light-emitting diode is 370-410nm.When wavelength was shortened, though the extinction efficient and the luminous efficiency of red emission fluorophor are improved, the luminous efficiency of light-emitting diode chip for backlight unit itself had but reduced unfriendly, always to improving brightness contribution was not arranged so shorten wavelength.In addition, the shown injurious effects that go out make the deterioration of luminescent coating b, resin and optics etc. just become very remarkable.On the other hand, when wavelength increases, thereby not only red light-emitting phosphor and also all the luminous efficiency of fluorophor all can reduce the deterioration that causes brightness.

And the luminescent coating of White LED is by forming with hardening of resin indigo plant, powder green, the red emission fluorophor.For corresponding fluorophor, preferably use its spectrum to have the fluorophor of following feature: in the blue light region of wavelength, glow peak to be arranged, glow peak is arranged in wavelength is the green Region of 510-530nm and in wavelength is the red light district of 620-640nm, glow peak is arranged as 440-460nm.That is, preferably using spike length to send out as the blueness of 440-460nm stretches fluorophor, spike length and is the green emission fluorescent body of 510-530nm and the spike length red emission fluorophor as 620-640nm.

For the fluorophor with above-mentioned emission characteristics, as mentioned above, what be fit to use has: the blue emission fluorophor, it is made up of general formula 1 expression: (Sr _1-x-yBa _xCa _yEu _z) ₁₀(PO ₄) ₆.Cl ₂Green emission fluorescent body, it is made up of general formula 2 expressions: (Ba _1-x-y-zSr _xCa _yEu _z) (Mg _1-uMn _u) Al ₁₀O ₁₇The red emission fluorophor, it is made up of general formula 3 expressions: (La _1-x-yEu _xM _y) ₂O ₂S.

Notice that in above-mentioned general formula 1-2, the value of x and y can comprise 0.And in above-mentioned general formula 3, partial L a can be replaced by Eu, and partial L a can be further by M element Sb for example, Sn, replacements such as Sm.These substituted elements M can not change the long and half-peak breadth of spike in the emission spectrum.But, in the grain size of fluorophor the trend of increase is arranged, thereby particle being easy to precipitate in the slurries of fluorophor, brightness simultaneously has the trend that is improved.The grain size of fluorophor is set in 80 μ m or littler, preferably 60 μ m or littler.

And the optical emission spectroscopy of preferred white LED has glow peak and have glow peak in wavelength is the green Region of 510-530nm in wavelength is the blue light region of 440-460nm; Each glow peak has 50nm or littler half-peak breadth respectively.

The half-peak breadth of the crest in being formed on blue light region and green Region is 50nm or more hour, can provide by White LED blueness emission and that be mixed with less amount and the light of green light.In addition, more preferably being formed on wavelength is that the half-peak breadth of the crest in the red light district of 620-640nm also is 50nm or littler.Above-mentioned White LED can be achieved by using above-mentioned fluorophor.

As indicated above, in LCD according to the present invention, because the emission spectrum and the compatibility between the colored filter of White LED are controlled suitably, the colorrendering quality of display is very excellent.So, LCD can be widely used in various products, described product comprises mobile communications device such as portable phone, mobile phone etc., OA (office automation) device is as PC etc., household electrical appliance, audio-visual equipment, various switches, various display unit such as light source display panel backlight etc.

Specific embodiment

Next, will more specifically explain with reference to the accompanying drawings and illustrate according to the embodiment of White LED of the present invention.

White LED according to the present invention has adopted cross section structure as shown in Figure 1.According to following manner this White LED is estimated.That is to say each 300 μ m ²Transmitting chip be arranged on the display box as corresponding light-emitting diode.Then, thus the electric current of 60mA is luminous by transmitting chip.The light of emission penetrates the indigo plant that is usually used in LCD, green and Red lightscreening plate.Then, transmitted light is introduced into integrating sphere, measures blue, green and red emission light in this integrating sphere respectively.

As a result, under light-emitting device fitted to be the condition of display, the color reproduction scope (colorrendering quality) of various light is estimated.About this point, the color reproduction performance is calculated as with respect to the area ratio by the desired color reproduction range of international standard (NTSC) regulation, described international standard (NTSC) has had explanation before this.And, with respect to the light that does not penetrate colored filter the brightness of White LED is estimated.

(CAS 140 by utilizing the compact array spectrometer for above-mentioned colorrendering quality; SystemsCorporation produces) estimate, and the brightness of White LED is estimated by utilizing MCPD equipment (OotsukaElectron Corporation production).

The method of＜production LED lamp 〉

Every kind with three kinds or more kinds of fluorophor powder makes the weight ratio of fluorophor be controlled to be 30 quality % with the organic siliconresin blending respectively, thereby prepares corresponding fluorophor paste.Then, each fluorophor paste of blending make the colourity of LED lamp in coordinate, be in x and y value (x=0.250-0.255 in scope y=0.235-0.240), thereby prepares mixed slurry.Take out the mixed slurry that part obtains like this, and drop on the LED of arrangement shown in Figure 1.Then, thus drip slurry under 100-150 ℃ of temperature through heat-treated and the sclerosis or the cured silicone resin produce white led lamps.

The execution mode of white led lamps will obtain more detailed explanation with reference to following embodiment and Comparative Examples.In following embodiment and Comparative Examples,, can use the light-emitting diode that has emission peak at 399nm wavelength place as light-emitting diode.

(embodiment 1)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.99Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.726Eu _0.274) (Mg _0.55Mn _0.45) Al ₁₀O ₁₇The sulphur lanthana fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (La _0.833Sb _0.002Eu _0.115) ₂O ₂S.

Three kinds of fluorophor are mixed with organic siliconresin respectively for every kind make that the concentration of fluorophor is thereby that 30 quality % prepare three kinds of fluorophor pastes.Then, with corresponding fluorophor paste with 20.1%, 19.5% and 60.4% (quality %) thus amount blending preparation mixing phosphor slurry.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to embodiment 1.

(embodiment 2)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.97Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.726Eu _0.274) (Mg _0.50Mn _0.50) Al ₁₀O ₁₇The sulphur lanthana fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (La _0.834Sb _0.001Eu _0.115) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus with corresponding fluorophor paste with 19.0%, 19.0% and 62.0% amount blending preparation mixing phosphor slurry.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to embodiment 2.

(embodiment 3)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.99Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.25Sr _0.475Eu _0.275) (Mg _0.55Mn _0.45) Al ₁₀O ₁₇The sulphur lanthana fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: La _0.883Sb _0.002Eu _0.115) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus corresponding fluorophor paste is mixed preparation mixing phosphor slurry with 20.2%, 19.0% and 60.8% amount.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to embodiment 3.

(embodiment 4)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.75Ba _0.23Ca _0.01Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.756Eu _0.274) (Mg _0.55Mn _0.45) Al ₁₀O ₁₇The sulphur lanthana fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (La _0.883Sb _0.002Eu _0.115) ₂O ₂5.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus corresponding fluorophor paste is mixed preparation mixing phosphor slurry with 20.1%, 19.5% and 60.4% amount.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to embodiment 4.

(embodiment 5)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.98Eu _0.02) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.756Eu _0.274) (Mg _0.60Mn _0.40) Al ₁₀O ₁₇The sulphur lanthana fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (La _0.883Sb _0.002Eu _0.115) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus corresponding fluorophor paste is mixed preparation mixing phosphor slurry with 20.3%, 19.8% and 59.9% amount.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to embodiment 5.

(embodiment 6)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.97Ca _0.02Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.35Sr _0.375Eu _0.275) (Mg _0.55Mn _0.45) Al ₁₀O ₁₇The sulphur lanthana fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (La _0.884Sb _0.001Eu _0.115) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus corresponding fluorophor paste is mixed preparation mixing phosphor slurry with 20.0%, 20.0% and 60.0% amount.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to embodiment 6.

(embodiment 7)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.99Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.75Eu _0.25) (Mg _0.55Mn _0.45) Al ₁₀O ₁₇The sulphur lanthana fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (La _0.883Sb _0.002Eu _0.115) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus corresponding fluorophor paste is mixed preparation mixing phosphor slurry with 20.2%, 19.9% and 59.9% amount.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to embodiment 7.

(embodiment 8)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.99Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.726Eu _0.274) (Mg _0.55Mn _0.45) Al ₁₀O ₁₇The sulphur lanthana fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (La _0.883Sb _0.002Eu _0.115) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus corresponding fluorophor paste is mixed preparation mixing phosphor slurry with 20.5%, 20.1% and 59.4% amount.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to embodiment 8.

(embodiment 9)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.97Eu _0.03) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.75Eu _0.25) (Mg _0.55Mn _0.45) Al ₁₀O ₁₇The sulphur lanthana fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (La _0.883Sb _0.002Eu _0.115) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus corresponding fluorophor paste is mixed preparation mixing phosphor slurry with 19.5%, 20.0% and 60.5% amount.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to embodiment 9.

(embodiment 10)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.99Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.726Eu _0.274) (Mg _0.55Mn _0.45) Al ₁₀O ₁₇The sulphur lanthana fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (La _0.882Sb _0.003Eu _0.115) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus corresponding fluorophor paste is mixed preparation mixing phosphor slurry with 19.6%, 19.8% and 60.6% amount.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to embodiment 10.

(Comparative Examples 1)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.59Ba _0.39Ca _0.01Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The zinc sulphide fluorophor that copper and aluminium excite is as the green emitting fluorophor, and it consists of: ZnS:Cu, Al; The yttrium oxysulfide fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (Y _0.94Eu _0.06) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus corresponding fluorophor paste is mixed preparation mixing phosphor slurry with 15.0%, 14.0% and 71.0% amount.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to Comparative Examples 1.

(Comparative Examples 2)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.59Ba _0.39Ca _0.01Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.864Eu _0.136) (Mg _0.74Mn _0.26) Al ₁₀O ₁₇The yttrium oxysulfide fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (Y _0.94Eu _0.06) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % for every kind respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus corresponding fluorophor paste is mixed preparation mixing phosphor slurry with 16.0%, 18.0% and 66.0% amount.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ of temperature through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to Comparative Examples 2.

Use the gained White LED to open with the White LED produced with according to each embodiment and Comparative Examples as the electric current that LCD backlight (liquid crystal indicator) feeds 40mA, thus luminous.To corresponding emission light, thereby measurement color reproduction scope and luminosity obtain the result shown in the following tabulation 1.

And, as conventional embodiment (Comparative Examples 3), can also produce a kind of LCD, wherein utilize cold-cathode fluorescence lamp (CCFL) as backlight.Color reproduction scope in the Comparative Examples 3 and luminosity degree also are listed in the table 1 simultaneously.

When the spectrum of each corresponding White LED is measured respectively and analyzed, can affirm that the spectrum among each embodiment all has: emission peak (glow peak) in wavelength is the blue light region of 440-460nm and the luminescence peak in wavelength is the green Region of 510-530nm and the luminescence peak in wavelength is the red light district of 620-640nm.And, have 50nm or littler half-peak breadth at each glow peak of blue, green and red light district.

On the contrary, in the spectrum of Comparative Examples 1, the spike of green Region and red light district is long all to be in outside the wave-length coverage of appointment of the present invention.And in the spectrum of Comparative Examples 2, the spike strong point of having only red light district is outside the wave-length coverage of appointment of the present invention.

[table 1]

Sample number	The color reproduction scope	Luminosity mcd
			Embodiment 1	98	400
Embodiment 2	96	400
			Embodiment 3	95	410
Embodiment 4	93	430
			Embodiment 5	96	410
Embodiment 6	95	420
			Embodiment 7	97	405
Embodiment 8	98	390
			Embodiment 9	97	410
Embodiment 10	96	400
			Comparative Examples 1	80	400
Comparative Examples 2	87	300
			Conventional embodiment (Comparative Examples 3)	65	-

Can clearly determine by the above result shown in the table 1, thus each White LED among the embodiment and use this White LED as LCD backlight all demonstrated 90 or higher high color reproduction performance and excellent emitting performance luminosity can be increased to 390mcd or higher.

(embodiment 11-15)

Next, repeat the process identical, thereby difference is for preparing the emission wavelength of Light-Emitting Diode the White LED of embodiment 11-15 by change shown in the table 2 with embodiment 1.In the same way, measure color reproduction scope and the luminosity of these embodiment.In this connection, regulate the blending ratio of blue, green and red light-emitting phosphor so that radiative colourity be within the specified scope (x=0.250-0.255, y=0.235-0.240).The result is as shown in table 2.

[table 2]

Sample number	The emission wavelength of light-emitting diode (nm)	The color reproduction scope	Luminosity mcd
				Embodiment 1	399	98	400
Embodiment 11	360	98	300
				Embodiment 12	370	98	460
Embodiment 13	380	98	430
				Embodiment 14	410	98	380
Embodiment 15	420	95	100

Can clearly be seen that from the result shown in the table 2 light-emitting diode has in the White LED of emission wavelength of 360-410nm in embodiment 11-15, can determine that color reproduction scope and luminosity are all very high, is preferred characteristic therefore.

Next, prepared White LED will more specifically be obtained explanation as the embodiment of LCD backlight.

(embodiment 16)

The electric current of 20mA is fed the White LED for preparing among the embodiment 1, and the light-emitting diode that this White LED is had the 400nm emission wavelength excites.The emission spectrum of this moment as shown in Figure 2.As shown in Figure 2, the emission wavelength that is used in the White LED among the embodiment 16 is included in peak and the peak in wavelength is the green Region of 510-530nm in the blue light region that wavelength is 440-450nm, and described peak has the half-peak breadth of 40nm and 30nm respectively, satisfies the requirement of " 50nm or littler ".

On the other hand, the colored filter that has spectrum shown in Figure 6 respectively is prepared as the RGB colored filter.In conjunction with above-mentioned White LED and RGB colored filter to produce LCD according to embodiment 16.

Utilization has the White LED of emitting performance as shown in Figure 2, measures the spectral distribution of the light that penetrates colored filter, and wherein the transmitted spectrum of this colored filter as shown in Figure 6.The result who measures as shown in Figure 7.In Fig. 7, the emission spectrum of solid line (B-CF) expression blue color filter, the emission spectrum of dotted line (G-CF) expression green color filter, the emission spectrum of thick dashed line (R-CF) expression Red lightscreening plate.

Can clearly be seen that by the result shown in the table 7, in the transmitted spectrum of green color filter, when the measured place in the 400-500nm wave-length coverage spectrum area (area 1) and when being in spectrum area (area 2) in the 400-600nm wave-length coverage, be 15% or littler by the equation area that (area 1/ area 2) * 100 (%) calculate than A.In the same way, when the measured place in the 400-550nm wave-length coverage spectrum area (area 3) and when being in spectrum area (area 4) in the 400-600nm wave-length coverage, be 90% or bigger by the equation area that (area 3/ area 4) * 100 (%) calculate than B.

And, the spectrum that penetrates the light of blue color filter comprises first peak (first summit) in the wave-length coverage that is present in 440-450nm, is present in second peak (second summit) in the wave-length coverage of 510-530nm, and the height at second peak be the first peak height 1/2 or still less.

First peak almost overlaps with the transmission peaks of blue color filter, thereby can affirm, is obtained effectively utilizing by the light that provides backlight.First peak is the emission peak that is caused by the blue-light-emitting fluorescent material that uses among this embodiment.Second peak is the light component by the green emitting fluorophor puberty among this embodiment.When the height at second peak be set to the first peak height 1/2 or still less the time, can obtain pure blue light, wherein be mixed with the green light components of less amount.

In addition, also detected the colorrendering quality of described LCD.Described colorrendering quality is expressed as a ratio relatively, this ratio is to be drawn as a triangle by the emission color of LCD (liquid crystal indicator) is drawn in the XYZ chromaticity diagram, and compare by triangle area that leg-of-mutton area and international standard (NTSC) is specified and to draw, the desirable color reproduction scope of wherein said international standard representative, and suppose that it is 100.

That is to say that the color reproduction scope is expressed as the relative value that calculates according to following formula: (area of the delta-shaped region of the area/NTSC appointment of the delta-shaped region of expression emission color in the CLE chromatic diagram of the LCD of embodiment) * 100 (%).

In above-mentioned XYZ chromaticity diagram, LCD means and can show the light with the colourity that is in delta-shaped region, described delta-shaped region be by connect indigo plant, three launch points green and red light obtain.Therefore, when the area of the delta-shaped region in the above-mentioned XYZ chromaticity diagram was bigger, LCD can show the light with various colourities more.Therefore, we can say that this LCD has wide color reproduction scope and excellent color reproduction performance.

Concrete measurement result is shown in table 3 and table 4.In the spectrum of the light of the blue color filter in penetrating embodiment 16, the height (b2) at second peak in existence and the 510-530nm wave-length coverage is 0.34 to the ratio (b2/b1) between the height (b1) that is present in the first peak in the 440-450nm wave-length coverage, area is 9.6% than A, and area is 92% than B.

And relevant with the color reproduction performance, the chromaticity coordinate that penetrates the light of blueness, green and Red lightscreening plate is respectively (0.14,0.06), (0.17,0.69), (0.69,0.31), and the NTSC ratio is 98%, thereby represents good color reproduction scope.

(embodiment 17-26)

Repeat the process identical with embodiment 16, difference is by changing the material and the thickness of White LED and colored filter, area is pressed change shown in the table 3 than A and area than B (half-peak breadth), thereby prepare the LCD of embodiment 17-26, they all have with embodiment 16 in identical structure.About embodiment 17-26, measure the half-peak breadth or the similar numerical value of corresponding emission peak.The result is shown in table 3 and table 4.

(Comparative Examples 4)

Prepare following fluorophor: the alkaline earth chlorophosphate phosphor that europium excites is as blue-light-emitting fluorescent material, and it consists of: (Sr _0.59Ba _0.39Ca _0.01Eu _0.01) ₁₀(PO ₄) ₆Cl ₂The chlorate MClO 3 fluorescent substance that europium and manganese excite is as the green emitting fluorophor, and it consists of: (Ba _0.864Eu _0.136) (Mg _0.74Mn _0.26) Al ₁₀O ₁₇The yttrium oxysulfide fluorophor that excites with europium is as red light-emitting phosphor, and it consists of: (Y _0.94Eu _0.06) ₂O ₂S.

Three kinds of fluorophor are mixed making that the concentration of fluorophor is 30 quality % respectively with organic siliconresin, thereby prepare three kinds of fluorophor pastes.Then, thus with corresponding three kinds of fluorophor pastes with 16.0%, 18.0% and 66.0% amount blending preparation mixing phosphor slurry.This mixed slurry is dropped on the LED subsequently, thus drip slurry under 140 ℃ through heat-treated and with organic siliconresin sclerosis with solidify the White LED of producing according to Comparative Examples 4.

The half-peak breadth at the peak that blue light region and green Region form in emission spectrum is respectively 60nm and 30nm.By the White LED among the embodiment 22 being substituted by the White LED in the Comparative Examples 4, thereby prepare the LCD of Comparative Examples 4.

Carry out with embodiment 22 in identical measurement, the result is the height (b2) that is present in second peak in the 510-530nm wave-length coverage to the ratio (b2/b1) of the height (b1) that is present in the first peak in the 440-450nm wave-length coverage is 0.55, this ratio is greater than 1/2.In addition, though area is 90.2% than B, area is 16.2% than A, and is 78% based on the color reproduction scope of NTSC ratio, thereby has been deterioration.

(Comparative Examples 5)

Repeat the process identical with Comparative Examples 4, difference be to use and consist of (Sr, Ba) ₂SiO ₄: Eu ²⁺The green emitting fluorophor, thereby prepare the White LED of Comparative Examples 5, it have with Comparative Examples 4 in identical structure.

Carry out with Comparative Examples 4 in identical measurement, the result is second peak that does not observe the light that penetrates blue color filter.Area is 19.5% than A, and area is 66% than B, and is 65% based on the color reproduction scope of NTSC ratio.

About this point, the inventor has attempted making the blue light region that forms in the emission spectrum of White LED and the peak of green Region to be separated for Gaussian curve by supposing them.But, can't obtain satisfied result, to such an extent as to abandoned the quantitative analysis at peak.But fully aware of is, in the half-peak breadth at the peak of green Region fully greater than 50nm.

The emission spectrum of used White LED as shown in Figure 8 in the LCD of Comparative Examples 5.And penetrate corresponding colored filter light spectrum as shown in Figure 9.

[table 3]

Sample number	Wavelength is the half-peak breadth in the blue-light-emitting district of 440-450nm	Wavelength is the half-peak breadth in the green emitting district of 510-530nm
			Embodiment 16	40(nm)	30(nm)
Embodiment 17	40	30
			Embodiment 18	40	30
Embodiment 19	40	30
			Embodiment 20	40	30
Embodiment 21	40	30
			Embodiment 22	40	30
Embodiment 23	40	30
			Embodiment 24	40	30
Embodiment 25	40	30
			Embodiment 26	40	30
Comparative Examples 4	60	30
			Comparative Examples 5	Greater than 50	Greater than 50

(Comparative Examples 6-7)

In the LCD of embodiment 16, the combined use of colored filter that thickness is controlled, thus produce the LCD of Comparative Examples 6-7.

In table 4 and 5, " b2/b1 " is the ratio of the height (b2) at second peak to the height (b1) of first peak, and the ratio of the spectrum area (g600) that the spectrum area (g500) that " g500/g600 " is made up of the light component with 400-500nm wavelength is made up of the light component with 400-600nm wavelength relatively.On the contrary, the ratio of the spectrum area (g600) formed by light component relatively of " g550/g600 " spectrum area (g550) of forming by light component with 400-600nm wavelength with 400-550nm wavelength.

Can clearly be seen that by the result in the table 5 even colored filter is made by identical materials, when the colored filter varied in thickness, it is quite different that the colorrendering quality of LCD also can become.That is to say,, do not consider the emission spectrum of White LED and the compatibility between the RGB colored filter, just can't obtain having the LCD of excellent colorrendering quality if not as the present invention.

Industrial usability

As indicated above, White LED of the present invention shows high brightness and excellent color reproduction performance. And according to liquid crystal display of the present invention, owing to use the spectrum backlight of this White LED and the transmitted spectrum of colored filter to obtain suitable control, this liquid crystal display is very excellent on the color reproduction performance. So the backlight and liquid crystal display that all use White LED of the present invention can show high brightness and excellent color reproduction performance. In addition, different from the cold-cathode fluorescence lamp (CCFL) of routine, do not need here to use harmful mercury, thereby the problem of environmental pollution just can not exist.

Claims (10)

1, a kind of White LED, it comprises:

Ultraviolet emission diode or purple light emitting diode; With the fluorophor that is used to launch at least three kinds of visible lights that comprise blue light, green light and red light;

The luminous intensity of wherein said ultraviolet emission diode or purple light emitting diode has peak value in the 360-410nm wave-length coverage, the emission spectrum of described White LED has: first glow peak in wavelength is the blue light district of 440-460nm, second glow peak in wavelength is the green light district of 510-530nm and the 3rd glow peak in wavelength is the red light district of 620-640nm

Described first to the 3rd glow peak that is in blue, green and red light district all has 50nm or littler half-peak breadth, and

The color reproduction scope of described White LED is 93% or bigger with respect to NTSC than (international standard ratio), and the brightness of this White LED is 380mcd or bigger.

2, according to the White LED of claim 1, the described fluorophor that wherein is used to launch blue light is the halophosphate fluorophor that europium excites, and it is by general formula 1 expression: (Sr _1-x-yBa _xCa _yEu _z) ₁₀(PO ₄) Cl ₂, wherein x, y, z satisfy following relation respectively: x＜0.2, y＜0.1, and 0.005＜z＜0.1.

3, according to the White LED of claim 1, the described fluorophor that wherein is used for transmitting green light is the chlorate MClO 3 fluorescent substance that europium and manganese excite, and it is represented by general formula 2: (Ba _1-x-y-zSr _xCa _yEu _z) (Mg _1-uMn _u) Al ₁₀O ₁₇, wherein x, y, z, u satisfy following relation respectively: x＜0.5, y＜0.1,0.15＜z＜0.4 and 0.3＜u＜0.6.

4, according to the White LED of claim 1, the described fluorophor that wherein is used to launch red light is the sulphur lanthana fluorophor that europium excites, and it is by general formula 3 expressions: (La _1-x-yEu _xM _y) ₂O ₂S, wherein M is the element of at least a Sb of being selected from and Sn, and x, y satisfy following relation respectively: 0.01＜x＜0.15, and y＜0.03.

5, a kind of backlight, it comprises the White LED according to one of claim 1-4.

6, a kind of LCD, it comprises:

White LED according to claim 1;

Use the backlight of this White LED; With

Be used to filter the colored filter of indigo plant, green, red light,

Wherein: with respect to the spectrum area of being made up of the light component with 400-600nm wavelength, the percentage of the spectrum area of being made up of the light component penetration green filter and that have the 400-500nm wavelength is 15% or littler; And with respect to the spectrum area of being made up of the light component with 400-600nm wavelength, the percentage of the spectrum area of being made up of the light component with 400-550nm wavelength is 90% or bigger.

7, according to the LCD of claim 6, wherein the light emission wavelength of the light-emitting diode that uses in described White LED is 360-410nm.

8, according to the LCD of claim 6, the spectrum that wherein penetrates the light of blue color filter comprises: be present in first summit in the 440-450nm wave-length coverage; With second summit that is present in the 510-530nm wave-length coverage; And the height of second summit be the first peak heights of roofs 1/2 or still less.

9, according to the LCD of one of claim 6-8, wherein when wavelength is the transmittance of 500nm, transmission factor at the blue color filter place be the max transmissive factor 90% or littler, and the transmission factor at the green color filter place be the max transmissive factor 95% or littler; And when wavelength is the transmittance of 600nm, the transmission factor at the green color filter place be the max transmissive factor 40% or littler.

10, a kind of LCD, it comprises:

Use White LED backlight of claim 1; With

Be used to filter the colored filter of indigo plant, green, red light,

Wherein: with respect to the spectrum area of forming by light component with 400-600nm wavelength, by the penetration green filter and the percentage with spectrum area that the light component of 400-500nm wavelength forms be 15% or littler; And with respect to the spectrum area of being made up of the light component with 400-600nm wavelength, the percentage of the spectrum area of being made up of the light component with 400-550nm wavelength is 90% or bigger.

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