KR20080012692A - Backlight assembly comprising fluorescent lamp surrounded by external tube having rhombus shape section - Google Patents

Abstract

A backlight assembly including a lamp surrounded by an external tube having a rhombus shape section is provided to refract light, emitted in four directions from a fluorescent lamp, through the external tube, thereby applying continuous parallel light to a diffusion plate and accordingly making luminance of the light uniform irrespective of a spaced distance from the fluorescent lamp. A backlight assembly(100) comprises a diffusion plate(120), at least one fluorescent lamp(210) disposed in a lower part of the diffusion plate, an external tube(220) and a bottom chassis(150). The external tube surrounds the fluorescent lamp, and comprises plural external walls having convex lens-shaped section. The bottom chassis receives the diffusion plate and the fluorescent lamp. The fluorescent lamp is disposed in a focus location of the concave lens within the external tube.

Description

Backlight assembly comprising fluorescent lamp surrounded by external tube having rhombus shape section}

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 cross-sectional view taken along line BB ′ of FIG. 1.

4 is a cross-sectional view taken along the line CC ′ of FIG. 1.

5 is a cross-sectional view of the backlight assembly according to another exemplary embodiment of the present invention, cut in the same direction as that of FIG. 4.

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

100: backlight assembly 130: diffuser plate

140: reflective sheet 150: bottom chassis

210: fluorescent lamp 220, 221: outer tube

220a, 220b, 220c, 220d, 221a, 221b, 221c, 221d: outer wall

The present invention relates to a backlight assembly, and more particularly to a backlight assembly with improved brightness uniformity.

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.

However, in such a fluorescent lamp, light is emitted from the lamp tube having a circular cross section to the transfer room, and as the distance between the optical paths increases as the distance from the fluorescent lamp increases, the dark portion or the bright line can be visually recognized. In order to prevent the dark portion or the bright line from being visually recognized, a large number of optical sheets are required, thereby increasing the manufacturing cost and inhibiting thinning of the product.

It is an object of the present invention to provide a backlight assembly that maintains luminance uniformity regardless of the separation distance from a fluorescent lamp.

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.

According to one or more exemplary embodiments, a backlight assembly includes a diffuser plate, at least one fluorescent lamp disposed under the diffuser plate, and an outer tube surrounding the fluorescent lamp. It includes an outer tube made up of a plurality of outer walls having a convex lens shape in cross section, and a bottom chassis for accommodating the diffusion plate and the fluorescent lamp.

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 exemplary 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. , An outer tube 220 surrounding the fluorescent lamp 210 and the fluorescent lamp 210.

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 210. 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 210 is required. The fluorescent lamp 210 may be 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 210 is disposed between the diffuser plate 120 and the reflective sheet 140 to emit light to display a screen of the liquid crystal display device, which is a passive light emitting device. The fluorescent lamp 210 will be described later in detail together with the outer tube 220.

The diffusion plate 120 may be disposed on the fluorescent lamp 210, 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 210.

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 210. 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 under the fluorescent lamp 210 and has a reflective surface to reflect the light emitted to the lower portion of the fluorescent lamp 210 upwards.

The bottom chassis 150 may have a rectangular shape, and sidewalls are formed along edges of the bottom surface such that the fluorescent lamp 210, 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 210 includes a lamp tube 211, a fluorescent material 212 coated on an inner surface of the lamp tube 211, an electrode 213 disposed at both ends of the lamp tube 211, and a discharge. A space 214, a lead wire 215 for applying power to the electrode 213, and a suture 216 for sealing the lamp tube 211.

As the fluorescent lamp 210, CCFL, EEFL, and the like may be used as described above. Hereinafter, the CCFL, which has a long life and excellent spectral characteristics and is most widely used, will be described as an example.

The lamp tube 211 is a tubular elongated tube that contains an enclosed gas, such as, for example, mercury atoms, present in the lamp tube 211 and defines a discharge space 214.

The lamp tube 211 is made of a material having transparency and rigidity such as glass, for example, to contain the encapsulation gas and not to lower the light brightness.

However, when such lamp tube 211 is used alone, light is emitted from the lamp tube 211 having a circular cross section to the transfer room, and the luminance of the light decreases as it moves away from the fluorescent lamp 210, resulting in uniform luminance. Since this may be degraded, the backlight assembly 100 according to the present embodiment further includes an outer tube 220 to be described later.

The tube diameter of the lamp tube 211 is provided in consideration of the electrical characteristics such that the lamp voltage and the starting voltage increases as the tube diameter becomes smaller, and the influence of temperature is easily provided.

A fluorescent material 212 is coated on the inner surface of the lamp tube 211, and the fluorescent material 212 may serve to generate visible light by colliding with ultraviolet rays. That is, the electrons discharged from the electrode 213 collide with the encapsulation gas, and ultraviolet rays are generated from the excited encapsulation gas, and the ultraviolet rays emit light with visible light from the fluorescent material 212.

As the fluorescent material 212, rare earth elements, for example, yttrium (Y), cerium (Ce), and terbium (Tb) may be used, and a three-wavelength type of white-based mixture of blue, green, and red phosphors may be used. Can be.

The electrode 213 is formed at both ends of the lamp tube 211, and when an external voltage is applied to the electrode 213, electrons present in the lamp tube 211 collide with the electrode 213 to emit secondary electrons. The discharge is thereby started.

The discharge space 214 is a space defined by the lamp tube 211, which contains a sealed gas. As the encapsulation gas, for example, rare earth gases such as 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.

The electrode 213 is connected to an external power source by the lead wire 215 and receives a high voltage through the lead wire 215.

Both ends of the lamp tube 211 are sealed by the sutures 216 to prevent the encapsulation gas and the like from leaking out.

One or more such fluorescent lamps 210 may be disposed in the backlight assembly 100 of the present embodiment, and as described below, an exterior including a plurality of outer walls 220a, 220b, 220c, and 220d having a convex lens shape in cross section. It is surrounded by the tube 220.

3 is a cross-sectional view taken along the line BB ′ of FIG. 1. Referring to FIG. 3, the outer tube 220 includes a plurality of outer walls 220a, 220b, 220c, and 220d having a convex lens shape in cross section.

The outer walls 220a, 220b, 220c, and 220d have a convex lens shape in cross section, and serve to deflect and condense the light of the fluorescent lamp 210 emitted to the transfer room in a predetermined direction.

That is, the outer wall (220a, 220b, 220c, 220d) is made of a long convex bar (bar) having a convex portion in both directions, the light emitted from the fluorescent lamp 210 is the outer wall 220a, 220b, 220c, And is condensed in a direction perpendicular to each of the outer walls 220a, 220b, 220c, and 220d.

The outer tube 220 of the present embodiment may have a cross section consisting of a plurality of outer walls 220a, 220b, 220c, and 220d having a convex lens shape, for example, a cross section having a rhombus shape. Light emitted from the outer tube 220 having a rhombus shape may emit parallel light in a direction perpendicular to the outer walls 220a, 220b, 220c, and 220d. Here, the rhombus shape does not mean only a quadrangle of four straight lines that are not orthogonal to each other, and is formed by connecting four convex lens shapes to include a shape similar to a rhombus.

However, the cross-sectional shape formed by the plurality of outer walls 220a, 220b, 220c, and 220d of the present embodiment is not limited to the rhombus shape, and the cross-section is, for example, the outer wall 220a of the convex lens as long as it can generate parallel light. , 220b, 220c, 220d) may be a polygonal shape, such as a triangular shape, a rectangular shape, is not particularly limited to the cross-sectional shape.

The fluorescent lamp 210 of this embodiment is disposed at the focal position of the convex lens inside the outer tube 220. In the convex lens, the light incident from the focus is emitted to the other surface of the convex lens to form parallel light. Therefore, even though light is emitted to the transfer room from the fluorescent lamp 210 made of a lamp tube 211 having a circular cross section, the cross section is convex. It is refracted by an outer tube 220 formed of lens-shaped outer walls 220a, 220b, 220c, and 220d, and is eventually emitted as parallel light.

Therefore, the light emitted from the fluorescent lamp 210 and refracted by the outer tube 220 is parallel light and has a uniform luminance regardless of the distance from the fluorescent lamp 210 (see 120 in FIG. 1). Is incident on.

4 is a cross-sectional view taken along the line CC ′ of FIG. 1. Referring to FIG. 4, the outer tube 220 of the present embodiment is disposed such that the plurality of outer walls 220a, 220b, 220c, and 220d form an inclination angle with the diffusion plate 120. That is, one outer wall 220c of the outer tube 220 and the diffusion plate 120 form an inclination angle θ ₁ , and the other outer wall 220d and the diffusion plate 120 have an inclination angle θ ₂ . Form.

Accordingly, the parallel light L ₁ emitted from one of the outer walls 220c having a convex lens section is incident on the diffuser plate 120 to have an inclination angle θ ₂ .

In this case, the outer tube 220 surrounding the fluorescent lamp 210 may be spaced at regular intervals such that the parallel light emitted through the outer tube 220 has luminance uniformity. That is, the parallel light L ₁ emitted from one outer wall 220c adjacent to the diffuser plate 120 and the parallel light L ₂ emitted from the other outer wall 220b adjacent to the reflective sheet 140 are predetermined. It is possible to maintain the spacing, and to arrange the outer tube 220 at this spacing to make the luminance uniform in front of the diffusion plate 120.

The outer tube 220 surrounding the fluorescent lamp 210 of the present embodiment may be arranged in plurality in parallel to the long side of the bottom chassis 150. In this arrangement, the light emitted from the fluorescent lamp 210 is refracted by the outer tube 220 to be emitted as parallel light, and the bottom chassis (to the liquid crystal display device) is connected to the bottom chassis 150 by parallel light emitted in the short side direction of the bottom chassis 150. The luminance in the short side direction of 150 is made uniform.

As a modified example of the present embodiment, the fluorescent lamp 210 and the outer tube 220 surrounding the fluorescent lamp 210 may be arranged in plurality in parallel to the short side of the bottom chassis 150. In this arrangement, the light emitted from the fluorescent lamp 210 is refracted by the outer tube 220 to be emitted as parallel light, and the bottom chassis (to the liquid crystal display) is provided with parallel light emitted in the long side direction of the bottom chassis 150. The luminance in the long side direction of 150 is made uniform.

According to the backlight assembly 100 according to the present exemplary embodiment, the light emitted from the fluorescent lamp 210 to the transfer room has a rhombus cross section including outer walls 220a, 220b, 220c and 220d having a convex lens shape in cross section. While refracting to parallel light in the outer tube 220 having a plurality of outer walls 220a, 220b, 220c, and 220d to form an inclination angle with the diffusion plate 120 to emit continuous parallel light, By arranging the outer tube 220 surrounding the 210 parallel to the long side or the short side of the bottom chassis 150, the luminance may be uniform in the short side or the long side direction of the bottom chassis 150.

Hereinafter, the backlight assembly 101 according to another exemplary embodiment of the present invention will be described in detail with reference to FIG. 5. 5 is a cross-sectional view of the backlight assembly according to another exemplary embodiment of the present invention, cut in the same direction as that of FIG. 4. For convenience of description, members having the same functions as the members shown in the drawings of the above embodiment are denoted by the same reference numerals, and thus description thereof is omitted. As shown in FIG. 5, the backlight assembly 101 according to the present exemplary embodiment basically has the same structure as the backlight assembly 100 according to the exemplary embodiment except for the following. That is, as shown in FIG. 5, in the backlight assembly 101 of the present embodiment, at least one of the plurality of outer walls 221a, 221b, 221c, and 221d of the outer tube 221 is parallel to the diffusion plate 120. Is placed.

The outer tube 221 of the present embodiment is also made of a plurality of outer walls 221a, 221b, 221c, and 221d having a convex lens section in the same manner as in the previous embodiment. Can be.

At least one outer wall 221d of the plurality of outer walls 221a, 221b, 221c, and 221d of the present exemplary embodiment is disposed in parallel with the diffusion plate 120. That is, the parallel light L ₃ emitted from the outer wall 221d adjacent to the diffuser plate 120 enters the diffuser plate 120 vertically. In this case, the outer tube 221 is disposed at regular intervals so that the light emitted from the fluorescent lamp 210 and refracted through the outer tube 221 maintains uniformity of luminance in the entire diffuser plate 120.

As in the previous embodiment, a plurality of outer tubes 221 surrounding the fluorescent lamp 210 of the present exemplary embodiment are disposed in parallel to the long side or the short side of the bottom chassis 150, and thus, the outer tube 221 of the bottom chassis 150 is disposed in the short side or the long side direction of the bottom chassis 150. The luminance can be made uniform.

According to the backlight assembly 101 according to the present exemplary embodiment, the light emitted from the fluorescent lamp 210 to the transfer room is formed in a rhombus shaped cross section consisting of outer walls 221a, 221b, 221c, and 221d having a convex lens shape in cross section. Refracted by parallel light in an outer tube 221 having a shape, and at least one of the plurality of outer walls 221a, 221b, 221c, and 221d is disposed in parallel with the diffuser plate 120 to vertically enter the diffuser plate 120. While emitting continuous parallel light, the outer tube 221 surrounding the fluorescent lamp 210 is disposed in parallel to the long side or the short side of the bottom chassis 150, whereby the luminance in the short or long side direction of the bottom chassis 150 is obtained. Can be made uniform.

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. You will 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, the light emitted from the fluorescent lamp to the transfer room is diffused by refracting through an outer tube having a rhombus cross section consisting of a plurality of outer walls having a convex lens shape in cross section, Continuous parallel light is incident on the plate so that the brightness of the light is made uniform regardless of the separation distance from the fluorescent lamp.

Claims (7)

Diffuser plate; At least one fluorescent lamp disposed under the diffusion plate; An outer tube surrounding the fluorescent lamp, wherein the outer tube includes an outer tube having a plurality of outer walls having a convex lens shape in cross section; And And a bottom chassis to accommodate the diffusion plate and the fluorescent lamp. According to claim 1, And the fluorescent lamp is disposed at a focus position of the convex lens inside the outer tube. The method of claim 2, The outer tube is a backlight assembly disposed so that the plurality of outer walls are inclined angle with the diffusion plate. The method of claim 3, wherein The outer tube is a backlight assembly having a rhombus cross section consisting of the plurality of outer walls having a convex lens shape in cross section. The method of claim 2, The outer tube surrounding the fluorescent lamp therein is disposed in parallel to the long side or short side of the bottom chassis. The method of claim 2, The outer tube is a backlight assembly wherein at least one of the plurality of outer walls are disposed in parallel with the diffusion plate. The method of claim 6, The outer tube is a backlight assembly having a rhombus cross section consisting of the plurality of outer walls having a convex lens shape in cross section.

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