KR20080014525A - Fluorescent lamp and backlight assembly comprising the same - Google Patents

Abstract

A fluorescent lamp and a backlight assembly comprising the same are provided to improve luminous characteristics and lifetime characteristics by using a fluorescent lamp including a mixed blue fluorescent material. A fluorescent lamp includes a lamp tube and a fluorescent material. The fluorescent material is formed with a first blue fluorescent material and a second blue fluorescent material. The first blue fluorescent material is coated on an inner surface of the lamp tube and includes BaMgAl10O17:Eu^2+. The second blue fluorescent material is coated on the inner surface of the lamp tube and includes CaMgSi2O6:Eu^2+. The blue fluorescent material is formed with the first blue fluorescent material of 20 to 90 weight percent and the second blue fluorescent material of 10 to 80 weight percent.

Description

Fluorescent lamp and backlight assembly comprising the same

1 is an exploded perspective view of a backlight assembly according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. 1.

3 is a graph showing the initial luminance efficiency of the fluorescent lamp included in the backlight assembly according to an embodiment of the present invention.

4 is a graph showing the life characteristics of the fluorescent lamp included in the backlight assembly according to an embodiment of the present invention.

5 is a graph showing the life characteristics of the fluorescent lamp included in the backlight assembly according to another embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

100: backlight assembly 130: diffuser plate

140: reflective sheet 150: bottom chassis

200: fluorescent lamp 300: fluorescent material

The present invention relates to a fluorescent lamp and a backlight assembly including the same, and more particularly, to a backlight assembly having improved life characteristics.

As the modern society is highly informationized, display devices are facing market demands for larger and thinner displays, and conventional CRT devices do not sufficiently satisfy these requirements. Therefore, plasma display panel (PDP) devices and PALC ( Demand for flat panel display devices, such as plasma address liquid crystal display panel (LCD) devices, liquid crystal display (LCD) devices, and organic light emitting diode (OLED) devices, is exploding.

Among the flat panel display devices, LCDs are widely used due to low power consumption. However, since LCDs do not have self-luminous ability, a separate light source for irradiating light is required. Fluorescent lamps are useful as such light sources. have.

Such fluorescent lamps include fluorescent materials, which influence the color reproducibility, brightness and lifetime characteristics of the fluorescent lamp, and in particular blue fluorescent materials have a great influence on the brightness and lifetime characteristics of the fluorescent lamp.

However, blue fluorescent materials currently used in fluorescent lamps have good luminance characteristics but poor lifetime characteristics, which shortens the lifetime of fluorescent lamps.

Therefore, there is a need for a fluorescent lamp with improved lifetime characteristics, including a blue fluorescent substance with good lifetime characteristics.

An object of the present invention is to provide a backlight assembly having good luminance characteristics and improved lifetime characteristics.

Another object of the present invention is to provide a fluorescent lamp included in the backlight assembly of the technical problem.

The technical problem of the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

A first blue phosphor containing Eu ^{2 +:} The backlight assembly according to an embodiment of the present invention to achieve a technical challenge, as the fluorescent substance applied to the lamp tube, the inner surface of the lamp tube, BaMgAl ₁₀ O ₁₇ , and CaMgSi ₂ O _6: the fluorescent material comprising a blue phosphor made of a second blue phosphor consisting of Eu ^{2 +,} and the fluorescent lamp comprises an electrode formed at both ends of the lamp tube, which houses the fluorescent lamp Contains the bottom chassis.

Fluorescent lamp according to one embodiment of the present invention to achieve the above another aspect, the lamp tube and, as a fluorescent material coated on the inner surface of the lamp tube, BaMgAl ₁₀ O _17: first blue containing Eu ^{2 +} a fluorescent material, and CaMgSi ₂ O _6: a second electrode formed on both ends of the fluorescent material, and the lamp tube comprising a blue phosphor made of a blue phosphor made of a Eu ^{+ 2.}

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a backlight assembly according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4.

1 is an exploded perspective view of a backlight assembly according to an embodiment of the present invention. Referring to FIG. 1, the backlight assembly 100 according to an exemplary embodiment may include a mold frame 110, a diffuser plate 120, an optical sheet 130, a reflective sheet 140, and a bottom chassis 150. , And fluorescent lamps 200.

The mold frame 110 is provided with a support end (not shown) formed along the sidewall, and supports the diffusion plate 120 and the optical sheet 130, and serves to protect the fluorescent lamp 200. The mold frame 110 may be provided with a fastening groove on the outer wall, and may be fastened with the bottom chassis 150 through this.

Meanwhile, since the liquid crystal display (not shown) is a passive light emitting device, a fluorescent lamp 200 is required. The fluorescent lamp 200 is a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), or an EEFL. (External Electrode Fluorescent Lamp) can be used.

The fluorescent lamp 200 is disposed between the diffuser plate 120 and the reflective sheet 140 to emit light in order to display a screen of the liquid crystal display, which is a passive light emitting device. The fluorescent lamp 200 will be described in detail later.

The diffusion plate 120 may be disposed above the fluorescent lamp 200, may be provided in a flat plate shape, and the diffusion material may be dispersed. The diffusion plate 120 serves to uniformize the luminance of the light emitted from the fluorescent lamp 200.

A plurality of optical sheets 130 are disposed on the diffuser plate 120. The optical sheet 130 serves to diffuse and collect light transmitted from the fluorescent lamp 200. The optical sheet 130 may include a diffusion sheet, a first prism sheet, a second prism sheet, and the like.

The reflective sheet 140 is disposed below the fluorescent lamp 200 and has a reflective surface to reflect the light emitted to the lower portion of the fluorescent lamp 200 upward.

The bottom chassis 150 may have a rectangular shape, and sidewalls are formed along edges of the bottom surface, such that the fluorescent lamp 200, the diffusion plate 120, the optical sheet 130, and the reflective sheet 140 are described in the sidewall. And a mold frame 140.

The bottom chassis 150 may be coupled to the mold frame 110 through hook coupling (not shown) and / or screw coupling (not shown).

2 is a cross-sectional view taken along the line AA ′ of FIG. 1. Referring to FIG. 2, the fluorescent lamp 200 includes a lamp tube 210, a fluorescent material 300 coated on an inner surface of the lamp tube 210, electrodes 220 disposed at both ends of the lamp tube 210, and electrodes. It consists of a lead wire 230 for applying power to the 220, the discharge space 240, and the suture 250 for sealing the lamp tube 210.

As the fluorescent lamp 200, CCFL, EEFL, etc. may be used as described above, and CCFL, which is most widely used because of excellent spectral characteristics, may be exemplified.

 The lamp tube 210 is a tubular elongated tube that contains an enclosed gas, such as, for example, mercury atoms, present in the lamp tube 210 and defines a discharge space 240.

The lamp tube 210 is made of a material having transparency and rigidity, such as glass, for example, to contain the encapsulation gas and not reduce the light brightness.

The tube diameter of the lamp tube 210 is provided in consideration of the electrical characteristics such that the lamp voltage and the starting voltage increases as the tube diameter decreases, and the effect of temperature and the life characteristics that increase as the tube diameter increases.

The electrode 220 is formed at both ends of the lamp tube 210, and when an external voltage is applied to the electrode 220, electrons present in the lamp tube 210 collide with the electrode 220 to emit secondary electrons. The discharge is thereby started.

The electrode 220 is connected to an external power source by the lead wire 230 and receives a high voltage through the lead wire 230.

The discharge space 240 is a space defined by the lamp tube 210, which contains the encapsulation gas. As the encapsulation gas, for example, gases such as mercury (Hg), argon (Ar), neon (Ne), and krypton (Kr) may be used alone or in combination. The encapsulation gas collides with the electrons emitted by the discharge and is excited and generates ultraviolet rays.

Both ends of the lamp tube 210 is sealed by the suture 250 to prevent the encapsulation gas and the like from leaking out.

The fluorescent material 300 is coated on the inner surface of the lamp tube 210, and the fluorescent material 300 serves to generate visible light by colliding with ultraviolet rays. That is, the electrons discharged from the electrode 220 collide with the encapsulation gas, and ultraviolet rays are generated from the excited encapsulation gas, and the ultraviolet rays emit light as visible light from the fluorescent material 300.

As the fluorescent material 300, for example, rare earth elements, for example, yttrium (Y), cerium (Ce), terbium (Tb), europium (Eu) -based materials and the like, may be included, red, green, blue A white wavelength type of a mixture of fluorescent materials of may be used.

The fluorescent material 300 is formed by mixing a red fluorescent material, a green fluorescent material, a blue fluorescent material, and an organic material including polymethyl-methacrylate (SiMA), SiO ₂ , terpineol, etc. After the preparation, the mixture on the paste is mechanically suctioned at one end of the lamp tube 210 to attach the mixture to the inner surface of the lamp tube 210, and then the mixture is heated to evaporate the organics. It may be fixed to the fluorescent lamp 200 by curing the residual material.

Example fluorescent material 300 of this embodiment, Y (P, V) O 4: red phosphor, BaMgAl ₁₇ O ₂₃ containing Eu ^{+ 3:} green fluorescent substance containing Eu ^2+, and BaMgAl ₁₀ O _17: a first blue phosphor containing Eu ^{2 +.}

The fluorescent material 300 of this embodiment having such a composition is a high color reproducible fluorescent material 300 having excellent color reproducibility of the red fluorescent material and the green fluorescent material.

However, these red fluorescent material and a BaMgAl ₁₀ O described above as the green fluorescent material and a combined first blue phosphor _17: When using the Eu ^{2 +,} due to its structural characteristics may not be excellent in life property, CaMgSi ₂ O ₆ : further comprises a second blue fluorescent material consisting of Eu ^{2 +} to prepare a fluorescent material 300.

In this embodiment the second blue phosphor, CaMgSi ₂ O _6: Eu ^{2 +} is BaMgAl ₁₀ O _17: has a strong resistance to ultraviolet light than the Eu ^{2 +,} so the luminance sustain ratio is excellent, y color coordinates are but a good advantage , the luminance is BaMgAl ₁₀ O _17: Eu is rather low compared to the substance ^{2 +.}

Therefore, in the present embodiment, as a blue fluorescent material, a first blue fluorescent material including BaMgAl ₁₀ O ₁₇ : Eu ²⁺ having high luminance but poor life characteristics, and CaMgSi ₂ O ₆ : Eu having excellent lifetime characteristics but low luminance By using a mixture of ²⁺ second blue fluorescent materials, it is possible to improve luminance and life characteristics while realizing high color reproducibility.

The blending ratio of the first blue fluorescent material and the second blue fluorescent material may be 20 to 90 wt% of the first blue fluorescent material, and 10 to 80 wt% of the second blue fluorescent material. When the second blue fluorescent material is less than 10% by weight, the lifespan characteristics of the fluorescent lamp 200 included in the backlight assembly 100 of the present embodiment may be deteriorated, and when the second blue fluorescent material exceeds 80% by weight, the luminance is reduced. Properties may be degraded.

Hereinafter, with reference to FIGS. 3 and 4, Experimental Example 1, Comparative Example 1, and Comparative Example 2, the life characteristics of the fluorescent lamp included in the backlight assembly according to an embodiment of the present invention will be described.

Experimental Example 1

BaMgAl ₁₀ O _17: first blue fluorescent substance 20% by weight consisting of Eu ^{2 +,} and CaMgSi ₂ O _6: mixing the second blue fluorescent material 80 consisting of Eu ^{2 +} wt.% To prepare a blue phosphor, and green phosphor BaMgAl ₁₇ of a material ^{_{O 23: Eu 2 +, Y}} (P, V) O 4 as a red fluorescent substance: was used was the Eu ^{+ 3,} applied to the lamp tubes with these fluorescent material and an organic material, and curing. Thereafter, an encapsulation gas was injected into the lamp tube, and the lamp tube was encapsulated to manufacture a fluorescent lamp.

(Comparative Example 1)

A fluorescent lamp was manufactured in the same manner as in Experiment 1, except that BaMgAl ₁₀ O ₁₇ : Eu ^{2 +} was used as a blue fluorescent material.

(Comparative Example 2)

CaMgSi ₂ O ₆ as a blue phosphor was prepared, and the fluorescent lamp in the same manner as in Experimental Example 1 except that the Eu ^{2 +} alone.

The initial luminance efficiency (luminance / y color coordinate) of the fluorescent lamps of Experimental Examples 1 to 2 was measured, and the results are shown in FIG. 3, and the luminance retention of the fluorescent lamps of Experimental Example 1 and Comparative Example 1 was measured, The results are shown in FIG.

3 is a graph showing initial luminance efficiency of a fluorescent lamp included in a backlight assembly according to an embodiment of the present invention.

As shown in FIG. 3, the fluorescent lamp of Comparative Example 1 using BaMgAl ₁₀ O ₁₇ : Eu ^{2 +} alone as a blue fluorescent material rapidly lowered its initial luminance efficiency, and CaMgSi ₂ O ₆ : Eu ² as a blue fluorescent material. The fluorescent lamp of Comparative Example 2 using ⁺ alone was excellent in initial luminance efficiency. However, Comparative Example 2 CaMgSi ₂ O _6: Eu ^{2 +} in the case of using the blue phosphor of the sole, the luminance is not high is as described above.

On the other hand, BaMgAl ₁₀ O _17: Eu ^{2 +} first blue fluorescent substance 20% by weight, and CaMgSi ₂ O ₆ consisting of a second experiment using the blue phosphor blue phosphor were mixed 80% by weight, consisting of Eu ²⁺ In Example 1, the initial luminance efficiency was higher than that of Comparative Example 1.

4 is a graph showing lifespan characteristics of a fluorescent lamp included in a backlight assembly according to an exemplary embodiment of the present invention.

Referring to Figure 4, BaMgAl ₁₀ O ₁₇ as a blue fluorescent materials: a fluorescent lamp of the Comparative Example 1 alone used as the Eu ^{2 +,} whereas a point at which the luminance is reduced to 50% of the about 20,000 sigan, BaMgAl ₁₀ O ₁₇ : first blue fluorescent substance 20% by weight consisting of Eu ^2+, and CaMgSi ₂ O _6: in experimental example 1 using the second blue phosphor blue phosphor were mixed 80% by weight, consisting of Eu ^{2 +} of more than 50% brightness It can be seen that the hold over 50000 hours.

According to the backlight assembly including the fluorescent lamp including the blue fluorescent material according to the present embodiment, by using a fluorescent lamp having excellent life characteristics and luminance characteristics and high color reproducibility, the life of the backlight assembly is extended and emitted The brightness of light can be increased.

Hereinafter, the backlight assembly and its lifespan characteristics according to another embodiment of the present invention will be described in detail. Since the external configuration of the backlight assembly according to the present exemplary embodiment is the same as the exemplary embodiment of the present invention, for convenience of description, a member having the same function as the backlight assembly of the exemplary embodiment will be omitted or simplified.

The backlight assembly according to the present embodiment includes a mold frame, a diffuser plate, an optical sheet, a reflective sheet, a bottom chassis, and a fluorescent lamp as in the previous embodiment, and their functions and arrangement are the same as in the previous embodiment. .

The fluorescent lamp includes the lamp tube, the fluorescent material applied to the inner wall of the lamp tube, and the electrodes formed at both ends of the lamp tube, as in the previous embodiment.

In this embodiment the fluorescent substance is the previous embodiment in the same manner, BaMgAl ₁₀ O _17: first blue phosphor containing Eu ^{2 +,} and CaMgSi ₂ O _6: blue phosphor made of a second blue phosphor consisting of Eu ^{2 +} And a blue fluorescent substance comprising 20 to 90 wt% of the first blue fluorescent substance, and 10 to 80 wt% of the second blue fluorescent substance.

As examples fluorescent material of this embodiment is different from the previous examples, LaPO _4: further includes a green fluorescent material containing Ce ^{+ 3.} In addition, the fluorescent material of the present embodiment may further include a red fluorescent material consisting of Y ₂ O ₃ : Eu ^{3 +} .

The green fluorescent substance and the red fluorescent substance of this embodiment are mixed and used with the blue fluorescent substance mentioned above, and a lifetime characteristic improves.

Hereinafter, the lifespan characteristics of the fluorescent lamp included in the backlight assembly according to the present embodiment will be described with reference to FIGS. 5 and Experimental Example 2 and Comparative Example 3. FIG.

Experimental Example 2

BaMgAl ₁₀ O _17: first blue fluorescent substance 20% by weight consisting of Eu ^{2 +,} and CaMgSi ₂ O _6: a mixture of the second blue phosphor 80% by weight consisting of Eu ^{2 +} was prepared in the blue phosphor, a green phosphor LaPO ₄ with a substance: was use of Eu ^{3 +,} and applied to the lamp tubes with these fluorescent material and an organic material, and curing: Ce ^{+ 3,} Y ₂ O ₃ as a red fluorescent substance. Thereafter, an encapsulation gas was injected into the lamp tube, and the lamp tube was encapsulated to manufacture a fluorescent lamp.

(Comparative Example 3)

A blue phosphor BaMgAl ₁₀ O _17: was prepared, and a fluorescent lamp in the same manner as in Experimental Example 2, except that used as the sole Eu ^{+ 2.}

The luminance retention of the fluorescent lamps of Experimental Example 1 and Comparative Example 3 was measured, and the results are shown in FIG. 4.

5 is a graph illustrating lifespan characteristics of a fluorescent lamp included in a backlight assembly according to another exemplary embodiment of the present invention.

5, a blue BaMgAl ₁₀ O ₁₇ by fluorescent material: Comparative fluorescent lamp of Example 3 alone used as the Eu ^{2 +} is, compared to the point at which the luminance is reduced to 80% from about 30,000 sigan, BaMgAl ₁₀ O _17: a first blue phosphor 20% by weight consisting of Eu ^2+, and CaMgSi ^₂ O _6: Eu ₂ ⁺ 2 blue phosphor brightness of 80% or more standing 80% by weight based on the blue phosphor blend consisting of experimental example 2 It could be confirmed that to maintain more than 50,000 hours.

According to the backlight assembly including the fluorescent lamp including the blue fluorescent material according to the present embodiment, by using a fluorescent lamp having excellent life characteristics and brightness characteristics, the life of the backlight assembly can be extended, and the brightness of the emitted light can be increased. .

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

According to the backlight assembly according to the present invention as described above, by using a fluorescent lamp containing a mixed blue fluorescent material, the life characteristics and luminance characteristics of the fluorescent lamp is improved.

Claims (8)

Lamp tube; As a fluorescent material applied to the inner surface of the lamp tube, a blue fluorescent material comprising a first blue fluorescent material comprising BaMgAl ₁₀ O ₁₇ : Eu ^{2 +} , and a second blue fluorescent material consisting of CaMgSi ₂ O ₆ : Eu ^{2 +} . Fluorescent material comprising a; And A fluorescent lamp comprising electrodes formed on both ends of the lamp tube. According to claim 1, The blue fluorescent material is a fluorescent lamp consisting of 20 to 90% by weight of the first blue fluorescent material, and 10 to 80% by weight of the second blue fluorescent material. The method of claim 2, The fluorescent material further comprises a green fluorescent material comprising BaMgAl ₁₇ O ₂₃ : Eu ^{2 +} . The method of claim 2, The fluorescent material further comprises a green fluorescent material comprising LaPO ₄ : Ce ^{3 +} . A lamp tube, a fluorescent material applied to the inner surface of the lamp tube, a first blue fluorescent material comprising BaMgAl ₁₀ O ₁₇ : Eu ^{2 +} , and a second blue fluorescent material consisting of CaMgSi ₂ O ₆ : Eu ^{2 +} . A fluorescent lamp comprising a fluorescent material including a blue fluorescent material, and electrodes formed at both ends of the lamp tube; And A backlight assembly comprising a bottom chassis for receiving the fluorescent lamp. The method of claim 5, The blue fluorescent material comprises 20 to 90% by weight of the first blue fluorescent material, and 10 to 80% by weight of the second blue fluorescent material. The method of claim 6, The fluorescent material further comprises a green fluorescent material comprising BaMgAl ₁₇ O ₂₃ : Eu ^{2 +} . The method of claim 6, The fluorescent material further comprises a green fluorescent material comprising LaPO ₄ : Ce ^{3 +} .

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