KR20070053931A - Color liquid crystal display panel without a color-filter - Google Patents

Abstract

The present invention relates to a color liquid crystal display device without a color filter. The present invention relates to a fluorescent film in which R, G and B phosphors are coated in a matrix or stripe so that three primary colors (R, G, B) of light correspond to an ultraviolet light source and a pixel. Including a back lighter; A liquid crystal module including a glass upper plate, a glass lower plate, and a liquid crystal interposed between the glass upper plate and the glass lower plate; Pixel driving means; There is provided a color liquid crystal display without color filter including optical stacks.

According to the present invention, a color liquid crystal display device capable of utilizing various light sources without requiring a color filter is provided.

UV light, backlight, liquid crystal display

Description

Color liquid crystal display panel without a color-filter}

1 to 4 show schematic cross-sectional views showing a multilayered structure of a conventional liquid crystal display device using an edge type, a direct type, a back light of a surface light source and an LED light source, respectively.

5 to 8 show schematic cross-sectional views showing the multilayer structure of the liquid crystal display device of the present invention using the edge type, the direct type, the surface light source and the ultraviolet light source backlight of the LED light source, respectively.

* Description of the symbols for the main parts of the drawings *

21 polarizing film, 22 color filter, 23 transparent electrode

24; alignment layer 11; glass top 12; liquid crystal 12; and thin film

51; UV lamp 52; UV LED 60; fluorescent film

The present invention relates to a color liquid crystal display device without a color filter.

In general, a color liquid crystal display device includes a liquid crystal module and a backlight, which consist of a glass upper plate and a lower glass plate, and a liquid crystal injected therebetween. When voltage is applied to the pixels by the electrodes and thin film transistors formed on the upper glass plate and the lower glass plate, the liquid crystal is aligned and the light passes through only the pixels where the liquid crystal is aligned by the polarizing plates arranged on the upper glass plate and the lower glass plate. By the color image is implemented.

The backlight of the color liquid crystal display device having the above structure thus uses white light as a light source. The commonly used light source is to arrange one, two or many cold cathode fluorescent lamps, which are white light, at the edges or directly to make uniform vertical light through the light guide plate, the diffuser plate and / or the prism sheet to form a polarizing plate in the liquid crystal module. It has a structure that is incident through. As liquid crystal displays become larger in size, various backlight light sources have been considered. For example, a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), an LED, an OLED, a surface light source lamp or a plasma light emitting panel. All of these light sources apply a combination of white light.

However, white light is a complex light having various wavelengths of visible light, and there is a problem in that a method of solving the interference of refraction and reflection due to the wavelength difference is required while passing through the optical stack embedded in the backlight and the optical stack of the liquid crystal module. . In the case of the fluorescent lamp, the gas filled in the discharge passage is ionized into a plasma state under a high pressure environment and emits ultraviolet rays due to the change of the energy level of the filled gas material. You get white light. Thus, ultraviolet light is fundamental and white light is secondary. In some cases, it is much more economical to obtain an ultraviolet light source.

On the other hand, the manufacturing process of the color filter in the liquid crystal display device is a complicated manufacturing process, such as the pattern formation by the photomask and the jacking of the removal dye, accounting for a large portion of the total manufacturing cost of the liquid crystal display. Therefore, there are attempts to ultimately eliminate color filters as well as those who want to make color filters inkjet printing instead of lithography. U.S. Patent 5,760,858 discloses a liquid crystal display device using a backlight that removes color filters and arranges R, G, and B in a stripe form by FED. However, in the situation where the FED method is a next-generation technology capable of realizing a complete display and is not yet commercially manufactured, the possibility of being used as a backlight of a liquid crystal display device is economically technically problematic in application.

The present invention is to provide a color liquid crystal display device using the ultraviolet light source backlight.

In addition, the present invention is to provide a color liquid crystal display device using an ultraviolet light source backlighter that does not require a color filter.

According to the present invention, a backlight including a fluorescent film coated with R, G, B phosphors on a matrix or stripe so that the three primary colors (R, G, B) of light correspond to the ultraviolet light source and the pixel; A liquid crystal module including a glass upper plate, a glass lower plate, and a liquid crystal interposed between the glass upper plate and the glass lower plate; Pixel driving means; There is provided a color liquid crystal display without color filter including optical stacks. In order to realize natural colors or intended colors, it is also possible to add a separate color, for example, Y (yellow) or modify R, G, and B to the three primary colors of light. In addition, a shadow mask may be disposed separately from the fluorescent film to increase the black effect.

Herein, the ultraviolet light source includes a hot cathode tube or a cold cathode tube as a light source. Cold cathode tube includes external electrode and internal electrode system. In addition, the surface light emitting source includes a counter electrode method and a surface discharge method, and a dielectric electrode (or “dielectric barrier discharge electrode”) method which is an external electrode method of a direct discharge method and a surface emission method. Ultraviolet frequency depends on the type of gas and the voltage applied. In general, the cathode ray tube and the surface light source method are known to use ultraviolet rays having a light emission peak in a 253.7 nm wavelength region by filling mercury and neon. On the other hand, in the case of filling the Xe gas, it is known to use ultraviolet rays having a light emission peak in the 147 nm wavelength region at high voltage (about 2 kV). Such a cathode or surface light source has a basic structure excluding a white phosphor from a general white light source for illumination. This is because ultraviolet rays are primarily generated by the change of energy level in the excited state of the gas filled in the discharge space. However, in order to transmit many ultraviolet rays, it is preferable to use a material that transmits ultraviolet rays. As the UV-transmitting material, crystals, pyrex, glass, transparent plastics chemically stable to ultraviolet rays or other transparent solids can be used. The ultraviolet light source also includes an ultraviolet LED. As an ultraviolet LED, the near-ultraviolet LED of 370 nm wavelength of Nichiwa Chemical, for example is marketed. Near-ultraviolet LEDs are LEDs that emit near-ultraviolet light having a light emission peak in a wavelength region of greater than 350 nm but less than 410 nm, preferably greater than 350 nm and less than 400 nm, and are gallium nitride compound semiconductors, silicon carbide compound semiconductors, and zinc selenide Photoelectric conversion devices (such as LEDs, laser diodes, surface-emitting laser diodes, inorganic electroluminescent (EL) devices, and organic EL devices) having a light emitting layer composed of an inorganic compound or an organic compound such as a compound semiconductor or a zinc sulfide compound semiconductor Include.

Many phosphors or fluorescent pigments emitting at each ultraviolet frequency are known. For example, fluorescent materials based on halogen phosphates are known in the ultraviolet region having a light emission peak in the 253.7 nm wavelength region. In ultraviolet light having a light emission peak in the wavelength region of 147 nm, phosphors mainly used in PDPs, for example, red phosphors are Y ₂ O ₃ : Eu, Y ₂ SiO ₅ : Eu, Y ₃ Al ₅ O ₁₂ : Eu, Zn ₃ ( _{PO 4) 2: Mn, YBO} 3: Eu, Y 0 .65 Gd 0 .35 BO 3: Eu, GdBO 3: Eu, ScBO 3: Eu, LuBO 3: Eu , etc., and a green phosphor Zn ₂ SiO _4: Mn, BaAl ₁₂ O ₁₉ : Mn, BaMgAl ₁₄ O ₂₃ : Mn, SrAl ₁₂ O ₁₉ : Mn, ZnAl ₁₂ O ₁₉ : Mn, CaAl ₁₂ O ₁₉ : Mn, YBO ₃ : Tb, LuBO ₃ : Tb, GdBO ₃ : Tb, ScBO ₃ : Tb, Sr ₄ Si ₃ O ₈ Cl ₄ : Eu and the like, and blue phosphors are known CaWO ₄ : Pb, Y ₂ SiO ₅ : Ce, aMgAl ₁₀ O ₁₇ : Eu and the like.

Near-ultraviolet LEDs having a light emission peak in the near-ultraviolet wavelength region exceeding 350 nm and 410 nm or less, and the near-ultraviolet light emitted by the near-ultraviolet LED are absorbed to emit fluorescence having a light emission peak within the visible wavelength range of 380 nm or more and 780 nm or less. BACKGROUND ART A semiconductor light emitting device for emitting white light, which is formed by combining phosphors including a plurality of inorganic phosphors, is known. As such a semiconductor light emitting device, for example, a semiconductor light emitting device disclosed in Japanese Patent Application Laid-Open No. 11-246857, Japanese Patent Application Laid-Open No. 2000-183408, Japanese Patent Application Laid-Open No. 2000-509912 or Japanese Patent Application Laid-Open No. 2001-143869 is known. have.

Japanese Patent Laid-Open No. 11-246857 discloses a general formula (La _1-xy Eu _x Sm _y ) ₂ O ₂ A lanthanum oxysulfide phosphor represented by S (0.01≤x≤0.15, 0.0001≤y≤0.03) is used as a red phosphor, and has a light emitting layer made of gallium nitride compound semiconductor. Description of the Related Art A semiconductor light emitting device comprising a combination of near ultraviolet LEDs with emitting light has been described. Japanese Patent Application Laid-Open No. 2000-183408 discloses a blue phosphor.

(1) divalent europium reactivation substantially represented by the general formula (M1, Eu) ₁₀ (PO ₄ ) ₆ Cl ₂ (wherein M1 represents at least one element selected from the group of Mg, Ca, Sr and Ba) Halophosphate (europium-activated halophosphate) phosphor.

(2) general formula a (M2, Eu) O.bAl ₂ O ₃ (wherein M2 represents at least one element selected from the group of Mg, Ca, Sr, Ba, Zn, Li, Rb and Cs, a And b is a value of a number satisfying a> 0, b> 0, and 0.2 ≦ a / b ≦ 1.5).

(3) general formula a (M2, Eu _v , Mn _w ) O.bAl ₂ O ₃ (wherein M2 is at least one element selected from the group of Mg, Ca, Sr, Ba, Zn, Li, Rb and Cs) A, b, v and w are divalent europium substantially represented by a> 0, b> 0, value of a number satisfying 0.2 ≦ a / b ≦ 1.5, 0.001 ≦ w / v ≦ 0.6), and Manganese-activated aluminate phosphors are described.

Further, Japanese Patent Application Laid-Open No. 2000-509912 discloses BaMgAl ₁₀ O ₁₇ : Eu, Sr ₅ (PO ₄ ) ₃ Cl: Eu, ZnS: Ag (both light emission peak wavelength is 450 nm) as a blue phosphor, and ZnS: Cu as a green phosphor. (Luminescence peak wavelength 550 nm) and BaMgAl ₁₀ O ₁₇ : Eu, Mn (luminescence peak wavelength 515 nm) are Y ₂ O ₂ S: Eu ³⁺ (luminescence peak wavelength 628 nm), YVO ₄ : Eu ^{3 +} (Emission peak wavelength 620nm), Y (V, P, B) O ₄ : Eu ^{3 +} (Emission peak wavelength 615nm), YNbO ₄ : Eu ^{3 +} (Emission peak wavelength 615nm), YTaO ₄ : Eu ^{3 +} (Luminescence peak wavelength 615 nm) and [Eu (acac) ₃ (phen)] (luminescence peak wavelength 611 nm) are described.

On the other hand, Japanese Patent Application Laid-Open No. 2001-143869 discloses an organic LED having an emission peak in a wavelength range of bluish violet to near ultraviolet rays of 430 nm or less, or an organic material as an emission layer, or a wavelength range of blue violet to near ultraviolet rays using an inorganic material as a light emitting layer. Sr ₂ P ₂ O ₇ : Sn ^{4 +} , Sr ₄ Al ₁₄ O ₂₅ : Eu ^{2 +} , BaMgAl ₁₀ O ₁₇ : Eu ^{2 +} , SrGa ₂ S ₄ : Ce ^{_{3 +, CaGa 2 S 4:}} Ce 3 +, (Ba, Sr) (Mg, Mn) Al 10 O 17: Eu 2+, (Sr, Ca, Ba, Mg) 10 (PO 4) 6 Cl 2: Eu ^{_{2 +, BaAl 2 SiO 8:}} Eu 2 +, Sr 2 P 2 O 7: Eu 2 +, Sr 5 (PO 4) 3 Cl: Eu 2+, (Sr, Ca, Ba) 5 (PO 4) 3 Cl _{^{: Eu 2 +, BaMg 2 Al}} 16 O 27: Eu 2 +, (Ba, Ca) 5 (PO 4) 3 Cl: Eu 2+, Ba 3 MgSi 2 O 8 ^{_{: Eu 2+, Sr 3 MgSi 2}} O 8: Eu 2 + a is used as a green phosphor _{(BaMg) Al 16 O 27:} Eu 2 +, Mn 2 +, Sr 4 Al 14 O 25: Eu 2 +, ( _{SrBa) Al 2 Si 2 O 8} : Eu 2 +, (BaMg) 2 SiO 4: Eu 2 +, Y 2 SiO 5: Ce 3 +, Tb 3 +, Sr 2 P 2 O 7 -Sr 2 B 2 O 7 ^{: Eu 2 +, (BaCaMg)} 5 (PO 4) 3 Cl: Eu 2 +, Sr 2 Si 3 O 8 -2SrCl 2: Eu 2+, Zr 2 SiO 4 -MgAl 11 O 19: Ce 3 +, Tb 3 ^{_{+, Ba 2 SiO 4: Eu}} 2+, Sr 2 SiO 4: Eu 2 +, (Ba, Sr) SiO 4: Eu ^{2 +} in the are used, the red phosphor ^{_{Y 2 O 2 S: Eu 3}} +, YAlO ^_3: Eu ₃ ^+, Ca ₂ Y ₂ (SiO ₄ ) ₆ : Eu ^{3 +} , LiY ₉ (SiO ₄ ) ₆ O ₂ : Eu ³⁺ , YVO ₄ : Eu ^{3 +} , CaS: Eu ^{2 +} , Gd ₂ O ₃ : Eu ^{3 +} , Gd ₂ discloses the ^{_{Eu 3 +: O 2 S:}} Eu 3 +, Y (P, V) O 4.

In the present invention, the R, G, and B phosphors are selected according to the type of light source and the wavelength of the ultraviolet ray and applied to the fluorescent layer in a matrix or stripe form so that the three primary colors (R, G, B) of light correspond to the pixels.

The liquid crystal is injected into the space formed by the transparent spacer. In order to determine the reference point of alignment of the liquid crystal, an alignment film is generally formed inside the glass upper plate and the glass lower plate. Here, the pixel driving means refers to a means for aligning and driving the liquid crystal by applying a voltage to the pixel by the electrode array and the thin film transistor. Here, the optical layers are a color filter for realizing color by a combination of three colors, a diffusion plate for evenly dispersing light, a polarizing film, a prism sheet, and a roughness enhancing film (BEF) disposed in the vicinity of the glass upper plate and the glass lower plate. Refers to. Roughness enhancing film (BEF) may be used incorporating diffuser, polarizing and / or prism sheet functionality. The diffuser plate, prism sheet and roughness enhancing film (BEF) are arranged between the back lighter and the liquid crystal module except that two polarizing films are placed on the glass top plate and the glass bottom plate, and color filters are usually formed on the glass top plate. It can be integrated into the lighter.

The surface light source lamp is basically an improvement of the cold cathode fluorescence method, and is simply an improvement of the tube-type single channel CCFL method to form multiple channels, which was originally developed due to the need for surface lighting. It can be usefully used as. GE's US Patent Nos. 3,047,763 and 3,646,383 disclose fluorescent lamps that are surface-luminescent by forming multiple channels by bonding glass plates. More complicatedly, U.S. Patent Nos. 5,850,122 and 5,479,069 disclose multi-channel surface emitting fluorescent lamps in which a metal plate and a glass plate are formed with channels. Corning's U.S. Pat.Nos. 6,301,932 (prior to date 1996.11.13), 6,559,599 (priority to date 1998.11.17), and U.S. Patent 5,834,888 (prior to date 1996.12.23) disclose a technique for forming a multichannel plate using a molten plate of glass. It is. In addition, a structure in which the multi-channel formation is formed by the partition wall method may be selected. It can be said that the manufacturing method is more disadvantageous in terms of cost than the melt plate method, but the multi-channel surface light source method described in Korean Patent Publication ((2000-26971) 1998.10.24) provides sand to make a multi-channel discharge space between the lower plate and the upper plate. It is formed into a partition wall type by a blast or etching method, and the discharge light emission method is adopted by opposing electrodes (installed on the partition wall facing surface). U.S. Patent Nos. 6,034,470 (2000.05.07) and 6,060,828 (2000.05.09) disclose structures that facilitate discharge by forming protrusions on one of the counter electrodes, and Korean Patent Publication No. 273598 discloses a multi-channel glass plate having a partition structure. Disclosed is a backlight having a counter electrode inserted therein. Korean Patent Publication No. 375,615 discloses a structure in which a discharge is generated at a specific site by having a protrusion on a counter electrode as a Korean application of US Pat. No. 6,034,470, and Samsung Electronics Patent Publication No. 2001-2111, 2204, 2206 provides a back-lighter with a surface discharge structure. Patent No. 10-363260 discloses a surface discharge type backlighter in which one electrode of the counter electrode has a protrusion similar to that of the US patent. The surface light source (FFL) has no big difference in principle with the cathode tube method, but it is developed by using a rare gas such as Xe and Ne as a filling gas and using a surface discharge structure through a dielectric, similar to PDP. have. The present invention includes all such light source structures except that phosphor coating and ultraviolet ray transmitting materials are employed.

In the present invention, the fluorescent film forms one flat plate separately from the discharge space. The fluorescent film is preferably coated with R, G, B phosphors or fluorescent pigments on a matrix or stripe so that the three primary colors (R, G, B) of light correspond to the pixels according to the frequency of ultraviolet rays on the back surface. Such phosphors or pigments are optically transparent and stable to ultraviolet light, for example, dispersed in an epoxy and applied onto a matrix or stripe. From the ultraviolet light source to the fluorescent film, ultraviolet light can be guided or reflected, diffused or dispersed as appropriate. Such a fluorescent film may be manufactured in a separate sheet form or as a coating layer of a glass plate.

The invention is illustrated by the following figures.

1 to 4 show a conventional liquid crystal display device using an edge type, a direct type, a back light of a surface light source and an LED light source, respectively. These figures are intended to illustrate the relative position and the dimensions are arbitrary. The basic structure of the liquid crystal display device includes: a glass plate 11 having a polarizing film 21, a color filter 22, a transparent electrode 23, and an alignment film 24; A liquid crystal module comprising a liquid crystal 12; a thin film transistor 24; an alignment glass 24; and a glass bottom plate 13 having a polarizing film 21; and an edge-type cold cathode fluorescent tube 17 according to the position and type of the light source. ), A direct cold cathode fluorescent tube 17, a back lighter 15 including a surface light source and a white LED light source 42 is provided. The dimming film 26 is disposed between the liquid crystal module and the backlight as necessary. Such dimming film is shown collectively can be formed complex or integrated in the polarizing film.

5 to 8 show an embodiment of the present invention corresponding to each of them according to the type of light source of FIGS. 1 to 4. Each of them uses edge type, direct type, surface light source and ultraviolet light source backlighter of LED light source. The cathode tube 51 is made of a quartz tube as an ultraviolet lamp and is not coated with a phosphor. The lamp 52 used in FIG. 8 is an ultraviolet LED. The present invention does not have a color filter. Instead, a fluorescent film 60 coated with R, G, and B phosphors in a stripe shape is formed on the back surface of the back lighter 50 glass plate 20.

According to the present invention, a color liquid crystal display device capable of utilizing various light sources without requiring a color filter is provided.

Claims (6)

A back lighter including an ultraviolet light source and a fluorescent film coated with R, G, and B phosphors on a matrix or stripe such that three primary colors (R, G, B) of light correspond to the pixel; A liquid crystal module including a glass upper plate, a glass lower plate, and a liquid crystal interposed between the glass upper plate and the glass lower plate; Pixel driving means; Color filterless color liquid crystal display comprising optical and optical stacks The color liquid crystal display of claim 1, wherein the light source of the backlight is an ultraviolet LED. The color liquid crystal display of claim 1, wherein the light source of the backlight is an ultraviolet cathode tube. The color liquid crystal display of claim 1, wherein the light source of the backlight is an ultraviolet surface light source. The color liquid crystal display device according to claim 4, wherein the light source of the backlight is mainly an ultraviolet surface light source having a wavelength of 253.7 nm. The color liquid crystal display device according to any one of claims 1 to 5, wherein the fluorescent film is a layer on which the phosphors of three primary colors (R, G, and B) of light are coated on the back surface of the flat glass.

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