KR20080037461A - Fluorescent substance for lamp and manufacturing method thereof and liquid crystal display with lamp comprising the same - Google Patents

Abstract

A phosphor for a lamp, a method for preparing the phosphor, and a liquid crystal display device containing the phosphor are provided to improve color purity and color reproducibility. A phosphor for a lamp comprises a granular red phosphor, a granular green phosphor; a granular blue phosphor; and a green inorganic pigment which is adhered to the green phosphor in an amount of 0.1-5 wt% of the green phosphor. Preferably the green inorganic pigment comprises cobalt green; and the cobalt green has a diameter of 10-100 nm. Preferably the green inorganic pigment is adhered to the green phosphor by a binder.

Description

A fluorescent substance for a lamp, a manufacturing method thereof, and a liquid crystal display having a lamp including the same {FLUORESCENT SUBSTANCE FOR LAMP AND MANUFACTURING METHOD THEREOF AND LIQUID CRYSTAL Display WITH LAMP COMPRISING THE SAME

1A is a graph showing emission spectra of red, blue, and green phosphors used in a lamp of a general liquid crystal display device;

1B is a graph showing a white light emission spectrum of a lamp used in a general liquid crystal display device;

2 is a view for explaining a green inorganic pigment and a phosphor for a lamp comprising the same according to the present invention;

3 is a flowchart illustrating a method of manufacturing a phosphor for a lamp according to the present invention;

4 is an exploded perspective view of a liquid crystal display device according to the present invention;

5 is a view for explaining the structure of a lamp according to the present invention;

Figure 6 shows the emission spectrum of the green phosphor according to the invention,

7 is a view showing a white light emission spectrum of a lamp including a phosphor according to the present invention.

Explanation of Signs of Major Parts of Drawings

10: upper cover 20: liquid crystal panel

30: mold frame 40: optical sheet

50: lamp 60: reflective sheet

70: backlight unit 80: lower cover

The present invention relates to a fluorescent substance for a lamp, a method for manufacturing the same, and a liquid crystal display device having the lamp including the same, and more particularly, a fluorescent substance for a lamp and a method for manufacturing the same, which can improve the color purity and color reproduction of the lamp A liquid crystal display device having a lamp is provided.

Recently, a flat panel display such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting diode (OLED) has been developed in place of the conventional CRT. The liquid crystal display device includes a thin film transistor substrate, a color filter substrate, and a liquid crystal panel in which a liquid crystal layer is positioned between both substrates. Here, since the liquid crystal panel is a non-light emitting device, the backlight unit may be positioned on the rear surface of the liquid crystal panel.

The lamp used for the backlight unit of the liquid crystal display device largely includes a linear light source, a surface light source and a point light source. Here, the cold light source includes a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), etc., and is mainly used as a backlight unit because of its price competitiveness.

The lamp includes a glass tube and electrodes provided inside both ends of the glass tube. Inside the glass tube, discharge gases such as mercury, argon and neon are enclosed. The inner surface of the glass tube is coated with a phosphor. The driving principle of the lamp configured as described above is as follows. When a high voltage is applied to both electrodes of the lamp, electron emission is caused by the electric field from the electrode. The emitted electrons excite mercury, and as mercury is excited, ultraviolet rays are emitted, which are converted into visible light by the phosphor and emitted to the outside. Here, the fluorescent lamp used in the backlight unit of the liquid crystal display device is used to mix the red, green, blue phosphor having an emission spectrum as shown in Figure 1a to apply to the inner surface of the glass tube in order to improve the color purity of the lamp. Accordingly, when a high voltage is applied to the lamp according to the driving principle described above, light is mixed to give a white light emitting spectrum as shown in FIG. 1B.

However, as shown in FIG. 1A, the green phosphor includes about 530 nm as a center wavelength and includes about 500 nm wavelengths, which are intermediate regions of blue and green wavelengths, and 590 nm wavelengths, which are intermediate regions of green and red wavelengths. When the white light is generated by the peak of the emission spectrum outside the central wavelength, as shown in the 'S' of Figure 1b it will have a light emission peak of 500nm and 590nm. The light emission peaks at 500 nm and 590 nm deviate from the center wavelengths of the red, green, and blue phosphors, and are a factor in reducing the color purity of the blue light, the green light, and the red light.

Accordingly, it is an object of the present invention to provide a phosphor capable of improving the color purity and color reproduction of the lamp.

Another object of the present invention is to provide a method for producing a phosphor that can improve the color purity and color reproduction of the lamp.

Another object of the present invention is to provide a liquid crystal display device having a lamp having improved color purity and color reproducibility.

The above object is, according to the present invention, in a fluorescent substance for lamps in which particulate red phosphors, green phosphors and red phosphors are mixed, adhered to the surface of the green phosphors, and 0.1 wt% to 5 wt% of the green phosphors. It is achieved by a phosphor for a lamp, characterized in that it further comprises a green inorganic pigment.

Here, the green inorganic pigment includes cobalt green, and the green inorganic pigment includes ZnO-TiO ₂ -NiO-CoO chemical formula.

In addition, the cobalt green may be particulate having a diameter of 10 nm to 100 nm.

Another object of the present invention is to prepare a particulate red phosphor, blue phosphor and green phosphor according to the present invention; Attaching 0.1 wt% to 5 wt% of the green inorganic pigment of the green phosphor on the surface of the green phosphor; It is achieved by a method for producing a phosphor for a lamp comprising the step of mixing a red phosphor, a blue phosphor and a green phosphor.

Here, the green inorganic pigment may be attached to the surface of the green phosphor by a binder (binder).

In addition, the green inorganic pigment may include cobalt green, and the green inorganic pigment includes ZnO—TiO ₂ —NiO—CoO chemical formula.

Another object of the present invention, according to the present invention, the liquid crystal panel; And a lamp for irradiating light to the rear of the liquid crystal panel, the lamp comprising: a glass tube forming an appearance; Lamp electrodes provided at both ends of the glass tube; And a fluorescent film coated on the inner surface of the glass tube by mixing particulate red phosphor, green phosphor, red phosphor, and green inorganic pigment, wherein the green inorganic pigment is attached to the surface of the green phosphor. Is achieved.

Here, the green inorganic pigment may be 0.1% by weight to 5% by weight of the green phosphor.

In addition, the green inorganic pigment may include cobalt green, and the green inorganic pigment includes ZnO—TiO ₂ —NiO—CoO chemical formula.

In addition, the cobalt green may be particulate having a diameter of 10nm to 100nm.

Hereinafter, a phosphor for a lamp according to the present invention will be described with reference to FIG.

In the phosphor for a lamp according to the present invention, as shown in Fig. 2, a green phosphor (g), a red phosphor (r) and a blue phosphor (b) are mixed. A particulate green inorganic pigment (c) is attached to the surface of the green phosphor (g).

In general, the green phosphor (g), the red phosphor (r) and the blue phosphor (b) used in the manufacture of phosphors for lamps are particulate and are usually pigments used in the manufacture of fluorescent lamps, such as cold cathode fluorescent lamps (CCFL). to be. Examples of the green phosphor (g) include Zn 2 SiO 4: Mn, YBO 3: Tb, and examples of the blue phosphor (b) include BaMbAl 110 O 17: Eu, and examples of the red phosphor (r) include Y (V, P) O 4: Eu + 3 and the like. However, examples of the green, red, and blue phosphors g, r, and b are not limited to the above-described substrate, and of course, all commonly used phosphors can be applied. The mixing ratio of the green phosphor (g), the red phosphor (r) and the blue phosphor (b) may be set differently depending on the level of white light to be produced. That is, it is possible to control the light source color by adjusting the compounding ratio of the phosphor, and can be set to correspond to the color temperature and color coordinates that meet the consumer's request. The range of the white color of the white light, which is obtained by mixing the green phosphor (g), the red phosphor (r) and the blue phosphor (b), has a degree of coordinates of approximately X = 0.22 to 0.315 and Y = 0.24 to 0.329. desirable.

On the surface of the green phosphor g, a green inorganic pigment c is attached. As the green inorganic pigment according to the present invention, as long as it has a wavelength having a central wavelength in the wavelength range of about 530 nm and a transmittance in the wavelength range of about 500 nm and about 590 nm, such as the emission spectrum of the green phosphor g, the green inorganic pigment of the present invention It can be used as a pigment. For example, cobalt green may be used as a green inorganic pigment. Cobalt green is a greenish dark blue pigment produced by mixing and heating cobalt oxide and zinc oxide. Cobalt green has a chemical formula of ZnO—TiO ₂ —NiO—CoO. The green inorganic pigment (c) is preferably in the form of particles having a diameter of 10 nm to 100 nm on average. The reason is that if the diameter of the green inorganic pigment (c) is smaller than 10 nm, it is difficult to control, and it is not suitable for absorbing the transmitted light of 500 nm and 590 nm appearing in the green phosphor g. When the diameter of the green inorganic pigment (c) is larger than 100 nm, it is difficult to attach to the surface of the green phosphor (g), and the light absorption may be much lowered in luminance. The compounding amount of the green inorganic pigment (c) is suitably about 0.1% to 5% by weight of the green phosphor. If the blending amount is 0.1 wt% or less, it is not suitable for achieving a desired effect such as absorbing the transmitted light of 500 nm and 590 nm, and when 5 wt% or more is attached, the absorbance of the light may be much lowered.

The operation and effects of the phosphor for a lamp of the present invention will be described in detail in the following paragraphs.

Hereinafter, a manufacturing method of the phosphor for a lamp according to the present invention will be described with reference to FIG. 3.

 First, a green phosphor, a red phosphor, and a blue phosphor are prepared (S100). The method for producing the phosphor includes a solid phase method, a sol gel method, spray pyrolysis method, and the like. Briefly, among the solid phase method, the raw material reagents are mixed at the composition ratio, and heat treatment for phosphor synthesis is performed. After that, the hard phosphor is broken and washed to remove impurities. The particles are then cut and rounded to produce particulate red, blue and green phosphors, respectively.

Next, the prepared green inorganic pigment is attached to the surface of the green phosphor (S200). Green inorganic pigment is prepared so that the diameter of the regular particles having a diameter of about 10nm to 100nm, green inorganic pigment is prepared at a level of 0.1% to 5% by weight of the green phosphor. Here, the critical meaning of the numerical value is the same as that of the paragraph explaining the fluorescent substance for lamps mentioned above. The prepared green inorganic pigment is attached to the surface of the green phosphor using an adhesive means such as a binder. Here, the green inorganic pigment may be used as the green inorganic pigment of the present invention as long as it has a wavelength having a central wavelength at about 530 nm and a transmittance in the wavelength range of about 500 nm and about 590 nm, such as the emission spectrum of the green phosphor. For example, cobalt green may be used as a green inorganic pigment. Cobalt green is a greenish pigment made by mixing and heating cobalt oxide and zinc oxide. Cobalt green has a chemical formula of ZnO—TiO ₂ —NiO—CoO.

Subsequently, a green phosphor having a green inorganic pigment is mixed with red and blue phosphors to prepare a phosphor for a desired lamp (S300). As a result, a phosphor for a lamp having improved color purity and color reproducibility is produced. The operation and effects of the phosphor for a lamp manufactured by the method of the present invention will be described in detail in the following paragraphs.

Hereinafter, a liquid crystal display having a lamp including a phosphor for a lamp according to the present invention will be described with reference to FIGS. 4 to 5. In the following description, a liquid crystal display device is described as an example among various display devices. However, the present invention is not limited thereto and may be applied to other display devices to which a backlight unit can be applied.

As shown in FIG. 5, the liquid crystal display device 1 according to the present invention includes a liquid crystal panel 20 for forming an image, a driver 25 for driving the liquid crystal panel 20, and a liquid crystal panel 20. A mold frame 30 supporting the edge of the substrate, a backlight unit 70 for irradiating light to the rear surface of the liquid crystal panel 20, a lower cover 80 for accommodating the backlight unit 70, and a lower cover 80. The upper cover 10 is coupled to each other and covers the front surface of the liquid crystal panel 20.

The liquid crystal panel 20 is injected between the thin film transistor substrate 21, the color filter substrate 22 attached to face the thin film transistor substrate 21, and the thin film transistor substrate 21 and the color filter substrate 22. It includes a liquid crystal (not shown). The liquid crystal (not shown) is injected between the thin film transistor substrate 21 and the color filter substrate 22 and then sealed. In addition, the liquid crystal panel 20 further includes a front polarizer (not shown) attached to the front surface of the color filter substrate 22 and a rear polarizer (not shown) attached to the rear surface of the thin film transistor substrate 21. The liquid crystal panel 20 is arranged in a matrix form of the liquid crystal cells forming a pixel unit, and forms an image by adjusting the light transmittance of the liquid crystal cells according to the image signal information transmitted from the driver 25.

In the thin film transistor substrate 21, a plurality of gate lines and a plurality of data lines are formed in a matrix form, and pixel electrodes and thin film transistors (TFTs) are formed at intersections of the gate lines and the data lines. The signal voltage applied through the thin film transistor is applied to the liquid crystal (not shown) by the pixel electrode, and the liquid crystal (not shown) is aligned according to the signal voltage to determine the light transmittance.

The color filter substrate 22 is formed with a common filter made of a color filter made of RGB pixels through which light passes and a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). . The color filter substrate 22 has a smaller area than the thin film transistor substrate 21, and a portion where the color filter substrate 22 and the thin film transistor substrate 21 overlap with each other becomes a display area of the liquid crystal panel 20 and does not overlap. The peripheral area of the display area becomes the non-display area of the liquid crystal panel.

The front polarizer and the rear polarizer are arranged to cross-polarize each other, the rear polarizer polarizes the light incident on the liquid crystal panel 20, and the front polarizer serves as an analyzer.

One side of the thin film transistor substrate 21 is provided with a driver 25 for applying a drive signal. The driver 25 includes a flexible printed circuit board (FPC) 26, a driving chip 27 mounted on the flexible printed circuit board 26, and a circuit board connected to the other side of the flexible printed circuit board 26. 28). The driver 25 shown illustrates a method of a chip on film (COF), and other known methods such as a taper carrier package (TCP) and a chip on glass (COG) may be used. In addition, the driver 25 may be mounted on the thin film transistor substrate 21.

The mold frame 30 is formed along the edge of the liquid crystal panel 20 to have a substantially rectangular shape. The mold frame 30 is disposed between the liquid crystal panel 20 and the backlight unit 70 to support the liquid crystal panel 20 spaced apart from the backlight unit 70.

The backlight unit 70 disposed on the rear surface of the liquid crystal panel 20 includes an optical sheet 40, a lamp 50, and a reflective sheet 60.

The optical sheet 40 is located on the rear surface of the liquid crystal panel 20 and includes a diffusion sheet 45, a prism sheet 43, and a protective sheet 41. Here, the diffusion sheet 45 is composed of a base plate and a bead-shaped coating layer formed on the base plate. The diffusion sheet 45 diffuses the light from the lamp 50 to supply the liquid crystal panel 20. The diffusion sheet 45 may be used by overlapping two or three sheets. Since the diffusion sheet 45 is not supported by the light guide plate, unlike the edge type, the diffusion sheet 45 may be somewhat thicker for strength. The prism sheet 43 is formed with a triangular prism-like prism on an upper surface thereof. The prism sheet 43 collects light diffused from the diffusion sheet 45 in a direction perpendicular to the plane of the upper liquid crystal panel 20. Two prism sheets 43 are usually used, and the micro prisms formed on each prism sheet 43 are at an angle. Light passing through the prism sheet 43 almost passes vertically to provide a uniform luminance distribution. The uppermost protective sheet 41 protects the prism sheet 43 that is weak to scratches.

As shown in FIG. 5, the lamp 50 includes a glass tube 51 forming an appearance, a lamp electrode 53 provided at both ends of the glass tube 51, and a lamp wire connected to the lamp electrode 53. 55, a fluorescent film 57 applied to the inner surface of the glass tube 51, and a discharge gas 59 filling the inside of the glass tube 51. The lamp electrode 53 is connected to an inverter (not shown) through the lamp wire 55 to receive a voltage. The discharge gas 59 of the lamp 50 according to the present invention contains mercury. In addition, the discharge gas 59 may further include argon and neon in order to facilitate discharge. When a high voltage is applied to both lamp electrodes 53 of the lamp 50, electron emission by the electric field occurs from the lamp electrode 53. The emitted electrons excite mercury and excite mercury to emit ultraviolet rays, which are converted into visible light by the fluorescent film 57 and are emitted to the outside.

In the fluorescent film 57 according to the present invention, the above-described phosphor for lamps is uniformly coated on the inner surface of the glass tube 51. In the fluorescent film 57 according to the present invention, a green phosphor, a red phosphor, and a blue phosphor are mixed. A particulate green inorganic pigment is attached to the surface of the green phosphor. Descriptions of the green phosphor, the red phosphor, the blue phosphor, and the green inorganic pigment follow the description of the above-described phosphor for a lamp and a method for manufacturing the same, and the descriptions thereof will be omitted since the above descriptions are the same.

The reflective sheet 60 is positioned between the lamp 50 and the lower cover 80 to reflect the light of the lamp 50 and to supply the light toward the diffusion film 45. The reflective sheet 60 may be made of polyethylene terephthalate (PET) or polycarbonate (PC).

Side molds 61 are located at both sides of the lower cover 80. More specifically, the ends of the lamp 50, which is positioned at both sides of the lamp 50 in the longitudinal direction, and inside the side mold 61, is provided with the lamp electrode 53 is inserted. The side mold 61 is provided with an insertion hole 62 into which the respective lamps 50 are inserted.

The lower cover 80 accommodates the backlight unit 70. The upper cover 10 has a display window to expose the effective surface of the liquid crystal panel 20 to the outside, and is coupled to the lower cover 80. The upper cover 10 and the lower cover 80 are coupled to each other to accommodate the liquid crystal panel 20, the mold frame 30, and the backlight unit 70 therein.

6 and 7, the operation and effect of the phosphor for a lamp according to the present invention will be described. 6 is a graph showing emission spectra of green, blue, and red phosphors together with emission spectra of cobalt green. 7 is a graph showing a white light emission spectrum of a phosphor for a lamp manufactured by attaching cobalt green to the surface of the green phosphor.

As described above, the green phosphor has a light emission peak of 500 nm and 590 nm as shown in 'S' of FIG. The light emission peaks at 500 nm and 590 nm deviate from the center wavelengths of the red, green, and blue phosphors, and are a factor in reducing the color purity of the blue light, the green light, and the red light.

However, as shown in Fig. 6, the cobalt green of the present invention exhibits high light transmittance near about 530 nm while low light transmittance around 500 nm and 590 nm such as 'S' in Fig. 1B. That is, the cobalt green has a light emission spectrum in the form of absorbing light emission peaks of 500 nm and 590 nm, such as 'S' of FIG. 1B. Accordingly, when cobalt green is attached to the surface of the green phosphor, the emission spectrum of the light generated from the green phosphor is lowered in the light emission peaks of 500 nm and 590 nm as shown in Fig. 6, and the color purity of blue light, red light and green light is reduced. Improve color reproduction. Accordingly, even when the blue phosphor, the red phosphor, and the green phosphor are mixed to generate white light, as shown in FIG. 7, the heights of the light emission peaks of 500 nm and 590 nm are lower in the present invention than in the prior art. Accordingly, it can be seen that the white light improves the color purity and color reproduction of the emission spectrum.

As described above, according to the present invention, there is provided a phosphor capable of improving the color purity and color reproduction of the lamp.

In addition, a method of manufacturing a phosphor capable of improving color purity and color reproducibility of a lamp is provided.

Also, a liquid crystal display device having a lamp having improved color purity and color reproducibility is provided.

Claims (13)

In the phosphor for lamps in which a particulate red phosphor, a green phosphor and a red phosphor are mixed, The phosphor for a lamp is attached to the surface of the green phosphor, further comprising 0.1 to 5% by weight of the green inorganic pigment of the green phosphor. The method of claim 1, The green inorganic pigment is a phosphor for a lamp, characterized in that it comprises cobalt green (cobalt green). The method of claim 2, The green inorganic pigment is a phosphor for a lamp, characterized in that containing the chemical formula of ZnO-TiO ₂ -NiO-CoO. The method of claim 1, The cobalt green is a phosphor for a lamp, characterized in that the particulate form having a diameter of 10nm to 100nm. Preparing particulate red phosphors, blue phosphors and green phosphors; Attaching 0.1 wt% to 5 wt% of the green inorganic pigment of the green phosphor on the surface of the green phosphor; A method of manufacturing a phosphor for a lamp comprising the step of mixing the red phosphor, the blue phosphor and the green phosphor. The method of claim 5, The green inorganic pigment is a method of manufacturing a phosphor for a lamp, characterized in that attached to the surface of the green phosphor by a binder (binder). The method of claim 5, The green inorganic pigment is a manufacturing method of the phosphor for a lamp, characterized in that it comprises cobalt green (cobalt green). The method of claim 7, wherein The green inorganic pigment is ZnO-TiO ₂ -NiO-CoO The manufacturing method of the phosphor for a lamp, characterized in that it comprises a chemical formula. A liquid crystal panel; It includes a lamp for irradiating light to the rear of the liquid crystal panel, The lamp includes a glass tube forming an appearance; Lamp electrodes provided at both ends of the glass tube; A red phosphor, a green phosphor, a red phosphor, and a green inorganic pigment in particulate form are mixed and coated on an inner surface of the glass tube, And the green inorganic pigment is attached to a surface of the green phosphor. The method of claim 9, Wherein said green inorganic pigment is 0.1 wt% to 5 wt% of said green phosphor. The method of claim 9, The green inorganic pigment includes a cobalt green (cobalt green). The method of claim 11, The green inorganic pigment is a liquid crystal display comprising a chemical formula of ZnO-TiO ₂ -NiO-CoO. The method of claim 9, The cobalt green is a liquid crystal display, characterized in that the particulate form having a diameter of 10nm to 100nm.

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