Full color display panel and color-separating substrate thereof

A full color display panel comprises an organic light-emitting area, a spectrum-modulation layer, a color-separating layer and a transparent substrate. In this case, the organic light-emitting area includes a plurality of pixels for emitting white light. The spectrum-modulation layer is doped with a fluorescent material and/or a phosphorescent material in a transparent protecting medium. The color-separating layer includes a light-shielding frame and a plurality of color filters. The light-shielding frame is disposed around the peripheral of the color filters. The color-separating layer is disposed on the transparent substrate. The spectrum-modulation layer is disposed above the color-separating layer. The organic light-emitting area is disposed above the spectrum-modulation layer.

This Non-provisional application claims priority under 35 U.S.C. § 119(a) on patent application Ser. No(s). 092114471 filed in Taiwan on May 28, 2003, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a color display panel and a color-separating substrate and, in particular, to a color display panel and a color-separating substrate comprising a spectrum-modulation layer.

2. Related Art

The colorizing technologies utilized in the present organic electroluminescent displays mainly include the following three. The first technology is “Three Primary Colors Light-emitting Method” that uses respectively three primary colors (Red, Green, and Blue) for an independent electroluminescent unit. The second technology is “Color Conversion Medium” that includes a blue light material and cooperates with a red organic fluorescent material and a green organic fluorescent material to generate various colors. The third technology is “Color Filter Method” that includes white light electroluminescent layer and color filters. Hereinafter, the color conversion medium technology is taken for an example and is described below.

Idemitsu Kosan Co. is one of the leaders in developing the color conversion medium technology. As shown inFIG. 1, a color display panel3comprises an organic light-emitting area31, a planarization layer32, a color conversion layer33, a glass substrate34and an encapsulating cap35. The organic light-emitting area31is disposed on the planarization layer32, the planarization layer32is disposed on the color conversion layer33, the color conversion layer33is disposed on the glass substrate34, and the encapsulating cap35is connected to the glass substrate34. In this case, the organic light-emitting area31includes a first electrode311, an organic functional layer312and the second electrode313, which are disposed on the planarization layer32in sequence. The organic functional layer312is made of a blue light material, so that the organic light-emitting area31can emit blue light. The color conversion layer33comprises a plurality of blue filters331, green filters332, red filters333, green conversion films332′, and red conversion films333′. The green conversion films332′ and the red conversion films333′ are disposed on the green filters332and the red filters333, respectively. The filters331,332, and333are respectively corresponding to the pixels of the organic light-emitting area31.

The blue light emitted from the organic light-emitting area31may pass through the green conversion film332′ and red conversion film333′, and is respectively converted into green light and red light. The green light and red light converted from the blue light pass the green filter332and the red filter333respectively, to increase the contrast of the green light and the red light. At the meanwhile, the blue light emitted from the organic light-emitting area31also passes through the blue filter331. Finally, a driving circuit is provided to produce the desired color screen according to the generated three primary colors (red light (R), green light (G), and blue light (B)).

In the conventional color display panel3, however, since at least three photolithography processes are necessary to form the green conversion films332′ and the red conversion films333′ on the green filters332and the red filters333, the manufacturing processes of the color display panel3are more complex and the cost thereof is increased. Furthermore, since the color display panel3includes the planarization layer32to make the whole panel more planar, the thickness of the whole panel3is also increased, which did not follow the trend toward lightweight and compact devices.

It is therefore a target to provide a color display panel and a color-separating substrate thereof to solve the above-mentioned problems.

SUMMARY OF THE INVENTION

In view of the foregoing, the invention is to provide a color display panel and a color-separating substrate thereof, which are without the conventional planarization layer and do not respectively utilize the color conversion films of three primary colors (R, G, B).

To achieve the above, the color display panel of the invention comprises an organic light-emitting area, a spectrum-modulation layer, a color-separating layer and a transparent substrate. In this invention, the organic light-emitting area includes a plurality of pixels for emitting white light. The spectrum-modulation layer includes a protecting medium, which is transparent and is doped with a fluorescent material and/or a phosphorescent material. The color-separating layer includes a light-shielding frame and a plurality of color filters, wherein the light-shielding frame is disposed around the peripheral of the color filters. The color-separating layer is disposed on the transparent substrate. The spectrum-modulation layer is disposed above the color-separating layer. The organic light-emitting area is disposed above the spectrum-modulation layer.

To achieve the above, a color-separating substrate of the invention comprises a spectrum-modulation layer, a color-separating layer and a transparent substrate. In this invention, the spectrum-modulation layer includes a protecting medium, which is transparent and is doped with a fluorescent material and/or a phosphorescent material. The color-separating layer includes a light-shielding frame and a plurality of color filters, wherein the light-shielding frame is disposed around the peripheral of the color filters. The color-separating layer is disposed on the transparent substrate. The spectrum-modulation layer is disposed above the color-separating layer.

As mentioned above, the color display panel and color-separating substrate thereof of the invention has a spectrum-modulation layer, which is used to improve the purity of white light emitted from the organic light-emitting area and to enhance the luminescent efficiency. Therefore, the white light with uniform and broadband radiation spectrum can be obtained, and satisfy the application of full color displays. Comparing with the conventional art, since the planarization layer is unnecessary in the invention, the structure of the color display panel of the invention is simplified. At the meanwhile, the thickness of the panel of the invention is reduced. In addition, since it is unnecessary to perform the photolithography processes to form the color conversion films of three primary colors (R, G, B), the manufacturing processes of the color display panel are simplified and the cost thereof is decreased. Moreover, the manufacturing yield is increased. Furthermore, since it is not to be restricted by the areas of the color conversion films, the viewing angle of the panel can be increased.

DETAILED DESCRIPTION OF THE INVENTION

With reference toFIG. 2, a color display panel1according to the first embodiment of the invention comprises an organic light-emitting area11, a spectrum-modulation layer12, a color-separating layer13and a transparent substrate14. In this embodiment, the organic light-emitting area11comprises a plurality of pixels for emitting white light. The spectrum-modulation layer12comprises a protecting medium, which is transparent and is doped with a fluorescent material and/or a phosphorescent material. The color-separating layer13comprises a light-shielding frame131and a plurality of color filters132. The light-shielding frame131is disposed around the peripheral of the color filters132. The color-separating layer13is disposed on the transparent substrate14. The spectrum-modulation layer12is disposed above the color-separating layer13. The organic light-emitting area11is disposed above the spectrum-modulation layer12.

As shown inFIG. 2, the organic light-emitting area11comprises a plurality of pixels for emitting white light. The pixel comprises a first electrode111, an organic functional layer112, and a second electrode113. The first electrode111is disposed above the spectrum-modulation layer12. The second electrode113is disposed above the first electrode111, and the organic functional layer112is sandwiched between the first electrode111and the second electrode113.

In such a case, the first electrode111is formed above the spectrum-modulation layer12by a sputtering method or an ion plating method. The first electrode111is usually used as an anode and made of a transparent conductive metal oxide, such as indium-tin oxide (ITO), aluminum-zinc oxide (AZO), or indium-zinc oxide (IZO).

The organic functional layer112in the current embodiment is disposed on the first electrode111. The organic functional layer112usually may contain a hole injection layer, a hole transporting layer, an electroluminescent layer, an electron transporting layer, and an electron injection layer (not shown). The hole injection layer comprises copper phthalocyanine (CuPc), the hole transporting layer comprises 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB), the electron injection layer comprises lithium fluoride (LiF), and the electron transporting layer comprises tris(8-quinolinato-N1,08)-aluminum (Alq). Each layer of the organic functional layer112may be formed upon the first electrode by utilizing evaporation, spin coating, ink jet printing, or printing. In addition, the light emitted from the organic functional layer112is broadband white light. This may be carried out by mixing electroluminescent materials with complementary colors such as orange and blue. Of course, other electroluminescent materials with complementary colors could be used.

The second electrode113is disposed on the organic functional layer112. Herein, the second electrode113is formed on the organic functional layer112by way of evaporation or sputtering. The material of the second electrode113can be aluminum, calcium, and magnesium-silver alloys. Of course, the material of the second electrode113can also be aluminum/lithium fluoride or silver.

Please refer toFIG. 2again. The spectrum-modulation layer12is disposed above the color-separating layer13, and comprises a protecting medium, which is transparent and is doped with a fluorescent material and/or a phosphorescent material. The fluorescent material and/or the phosphorescent material of the spectrum-modulation layer12can mix, scatter and excite the light, so as to enhance the luminescent efficiency, and to improve the purity of white light emitted from the organic light-emitting area11. Therefore, the white light with uniform and broadband radiation spectrum can be obtained. Furthermore, the demands of the color display panel can be satisfied. Moreover, the spectrum-modulation layer12is a planar structure with a single layer, which can also provide a planarization effect.

In this embodiment, the material of the protecting medium can be selected from but not limited to the group consisting of Polymethyl methacrylate (PMMA), tetrafluoroethylene resine, silicon resin, and silicon dioxide.

The protecting medium can be used to protect the first electrode111and the second electrode113. Since the protecting medium is adhesive, it can be used to attach with a cover plate15. That is, it is unnecessary to apply a sealing glue, and the encapsulation process can still be performed. In addition, the protecting medium is waterproof. The protecting medium can combine with the cover plate15or the passivation layer of the organic light-emitting area11(not shown) to form an encapsulation. Thus, the organic light-emitting area11can be prevented from water or oxygen.

In the current embodiment, the fluorescent material can be produced by mixing red fluorescent powder, green fluorescent powder, and/or blue fluorescent powder. The phosphorescent material can be produced by mixing red phosphorescent powder, green phosphorescent powder, and/or blue phosphorescent powder.

As mentioned above, the fluorescent material may include more than one organic dyes or more than one inorganic dyes. Herein, the red fluorescent powder may be an azo dye (organic dye) or Y2O2S:Eu3+, Bi3+(inorganic dye). The green fluorescent powder may be a CuPc dye (organic dye) or SrGa2O4:Eu2+(inorganic dye). The blue fluorescent powder may be a cyanine dye (organic dye) or SrGa2S4:Eu2+(inorganic dye). In this embodiment, the fluorescent material may be nano sized powder.

In addition, the phosphorescent material may include more than one organic dye or more than one inorganic dye. In the embodiment, the red phosphorescent powder may be 2,3,7,8,12,13,17,18-octaethyl-12H,23H-porphine platinum(II) [PtOEP] or Tris-(4,4,4-trifluoro-1-(2-thienyl)-1,3-butanediono)-1,10-phenanthroline europium(III) [Eu(TTA)3phen]. The green phosphorescent powder may be Bis(2-phenyl-pyridinato-N,C2)iridium(acetylacetone) [ppy2Ir(acac)] or Iridium(III) bis(tolypyridine)salicyclidene [tpyIrsd]. The blue phosphorescent powder may be Iridium-bis(4,6-di-fluorophenyl-pyridinato-N,C2)-picolinate [Firpic] or Bis[(4,6-difluorophenyl-pyridinato-N,C2)iridium(acetylacetone) [Fir(acac)]. In this embodiment, the phosphorescent material may be nano sized powder.

Referring toFIG. 2, the color-separating layer13comprises a plurality of color filters132surrounded with a light-shielding frame131. Herein, the light-shielding frame131is a black frame, which can avoid the mixing of lights of various colors. Of course, the light-shielding frame131can be made of reflective metal for controlling the direction of the light and increasing the utilization and uniformity of light. In addition, the light-shielding frame131is protruded out of the spectrum-modulation layer12(as shown inFIG. 3).

The color filters132comprise at least one red filter1321, at least one blue filter1322, and at least one green filter1323. In the current embodiment, the high purity white light produced by the spectrum-modulation layer12respectively passes the red filters1321, the blue filters1322and the green filters1323, so as to generate red light, blue light and green light.

Please refer toFIG. 2again. The transparent substrate14of the embodiment can be a flexible or rigid substrate. The transparent substrate14can also be a plastic or glass substrate. In particular, the flexible substrate or plastic substrate can be made of polycarbonate (PC), polyester (PET), cyclic olefin copolymer (COC), or metallocene-based cyclic olefin copolymer (mCOC).

As shown inFIG. 2, the color display panel1of the embodiment may further comprise an insulating layer16, which is disposed between the spectrum-modulation layer12and the organic light-emitting area11. Thus, the insulating layer16can prevent the substantially contact of the metals, which leads to short circuit. Herein, the insulating layer16is transparent and can be made of an organic compound or inorganic compound.

In addition, the color display panel1of the embodiment may further comprise a pixel defining layer17. The pixel defining layer17is disposed at the periphery of the first electrode111to define pixels within the organic light-emitting area11. The pixel defining layer17may be black to shield or reflect light. This could avoid mixing of the light emitted from the pixels, control the direction of the light, and increase the utilization and uniformity of light. In the embodiment, the light-shielding frame131protruded from the spectrum-modulation layer12may connect to the pixel defining layer17(as shown inFIG. 3). In practice, the light-shielding frame131may be combined with the pixel defining layer17as a whole, which provides the functions of light-shielding frame and pixel defining layer.

The color display panel1of the embodiment may further comprise a separating layer18, which is disposed on the pixel defining layer17. The separating layer18can separate each pixel of the organic light-emitting area11. In this case, the separating layer18is made of an insulating material and has a top width larger than a bottom width thereof.

Moreover, the color display panel I of the embodiment may further comprise a driving circuit (not shown). The driving circuit can be an active driving circuit or a passive driving circuit. The driving circuit is connected to the organic light-emitting area11and a power source (not shown).

With reference toFIG. 4A, a color-separating substrate2according to a second embodiment of the invention comprises a spectrum-modulation layer21, a color-separating layer22, and a transparent substrate23. Herein, the spectrum-modulation layer21comprises a transparent protecting medium doped with a fluorescent material and/or a phosphorescent material. The color-separating layer22comprises a plurality of color filters222surrounded with a light-shielding frame221. The color-separating layer22is disposed on the transparent substrate23, and the spectrum-modulation layer21is disposed above the color-separating layer22.

In addition, as shown inFIG. 4BandFIG. 4C, the light-shielding frame221may protrude out of the spectrum-modulation layer21.

Since the features and functions of the elements in the second embodiment are the same as those in the first embodiment, they are not repeatedly described hereinafter.

To sum up, the color display panel and color-separating substrate thereof of the invention has a spectrum-modulation layer, which is used to improve the purity of white light emitted from the organic light-emitting area and to enhance the luminescent efficiency. Therefore, the white light with uniform and broadband radiation spectrum can be obtained, and satisfy the application of full color displays. Comparing with the conventional art, since the planarization layer is unnecessary in the invention, the structure of the color display panel of the invention is simplified. At the meanwhile, the thickness of the panel of the invention is reduced. In addition, since it is unnecessary to perform the photolithography processes to form the color conversion films of three primary colors (R, G, B), the manufacturing processes of the color display panel are simplified and the cost thereof is decreased. Moreover, the manufacturing yield is increased. Furthermore, since it is not to be restricted by the areas of the color conversion films, the viewing angle of the panel can be increased.