KR101274798B1 - Optical member and backlight assembly having the same - Google Patents

Abstract

The present invention discloses an optical member having a uniform brightness and improved light efficiency, and a backlight assembly having the same. The disclosed optical member includes a diffuser for diffusing the incident light, a condenser for condensing the light diffused in the diffuser, and a light compensator disposed between the concentrator and the diffuser.

Fiber, Refraction, Reflection, Luminance, Optical Member

Description

Optical member, backlight assembly having the same {OPTICAL MEMBER AND BACKLIGHT ASSEMBLY HAVING THE SAME}

1A is a perspective view conceptually showing an optical member according to a first embodiment of the present invention;

FIG. 1B is a cross-sectional view of the optical member of FIG. 1A taken along the line II ′. FIG.

1C is a cross-sectional view showing an optical member according to a second embodiment of the present invention.

1D is a sectional view showing an optical member according to a third embodiment of the present invention;

FIG. 2 is a view showing an optical path in an optical fiber included in an optical member according to an embodiment of the present invention by Snell's law;

3 is an exploded perspective view illustrating an edge type backlight assembly according to an embodiment of the present invention.

Figure 4 is an exploded perspective view showing a direct type backlight assembly according to an embodiment of the present invention.

Explanation of symbols for main part>

150, 250, 350: optical member 151: diffusion material

153, 253, 353: optical fiber 155: prism pattern

200, 300: backlight assembly 210, 310: light source

230: Light guide plate 270, 370: Reflector plate

290, 390: Bottom Case

The present invention relates to an optical member, and more particularly, to an optical member having a uniform brightness and improved light efficiency, and a backlight assembly having the same.

The liquid crystal display device displays an image by adjusting the light transmittance of the liquid crystal using an electric field. To this end, the liquid crystal display includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix form, and a backlight assembly for irradiating light to the liquid crystal panel.

The backlight assembly includes a light source for emitting light, a power supply unit for supplying power to the light source, and an optical sheet for diffusing and condensing the light emitted from the light source.

The optical sheet is composed of a plurality of sheets such as a diffusion sheet, a prism sheet and a protective sheet in order to improve the quality of the image directly under the liquid crystal panel.

In the optical sheets as described above, a sheet for diffusion, a sheet for condensing, a sheet for protecting the sheet, and the like are sequentially stacked to fix the sheets, and any one of the sheets deviates from the alignment position. In this case, the light path may be changed or a problem of uneven brightness or deterioration of brightness may occur.

The backlight assembly provided with the optical sheets has a problem in that the assembling process of the optical sheets including the plurality of sheets is not easy.

The present invention provides an optical member that is formed integrally with a plurality of optical sheets, and is formed integrally between or within each optical sheet to reduce the unit cost, prevent luminance imbalance, and improve the light efficiency. There is a purpose.

In addition, an object of the present invention is to provide an optical member that is easy to assemble, and a backlight assembly having the same.

The optical member according to the first embodiment of the present invention for achieving the above object,

A diffusion unit for diffusing the incident light;

A condenser condensing light diffused from the diffuser; And

And a light compensating part disposed between the light collecting part and the diffusing part.

In addition, the optical member according to the second embodiment of the present invention,

A diffusion unit for diffusing the incident light;

A condenser condensing light diffused from the diffuser; And

And a light compensating part disposed at any one of the diffusion part and the light collecting part.

In addition, the backlight assembly according to the third embodiment of the present invention,

A light source disposed at one side to emit light;

A light guide plate disposed on a side of the light source to convert the light into a surface light source; And

And a diffusion part disposed on the front surface of the light guide plate to diffuse light, a light collecting part to collect light, and a light compensating part to change an optical path.

In addition, the backlight assembly according to the fourth embodiment of the present invention,

A plurality of light sources disposed on a surface to emit light;

A reflector disposed on a rear surface of the light source; And

And an optical member disposed on the front surface of the light source and including a diffuser for diffusing light, a light condenser for condensing light, and a light compensator for changing a light path.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1A is a perspective view conceptually illustrating an optical member according to a first exemplary embodiment of the present invention, and FIG. 1B is a cross-sectional view of the optical member of FIG. 1A taken along the line II ′.

1C and 1D are cross-sectional views showing optical members according to second and third embodiments of the present invention.

1A to 1D, an optical member 150 according to an embodiment of the present invention includes a diffuser A for diffusing light and a plurality of optical fibers 153 inside the diffuser A. FIG. ) Is provided with a light compensating unit (B), and a light collecting unit (C) formed on the diffusion (A) and the light compensating unit (B).

The optical member 150 may have a rectangular plate shape and may be formed of a transparent polymer material layer.

The polymer material layer may be polyethylene terephthalate (PET), poly methyl methacrylate (PMMA), polyethylene naphthalate, triacetyl cellulose, polyarylate, polyimide, polyether sulfone, cellophane, Polyethylene (PE), polypropylene and polyvinyl alcohol. In general, the polymer layer is mainly PET or PMMA material.

Although not shown, the optical member 150 may further include a protection part (not shown) for protecting the light collecting part C on the light collecting part C.

The diffusion part A may be made of a diffusion material 151, and the light collecting part C may be formed of a prism pattern 155 having an acid and a valley on the diffusion material 151. The light collecting unit C is not limited to the prism pattern 155, but may be formed of a pyramid pattern for condensing.

The optical fiber 153 may be formed as one layer between the diffusion portion A and the light collection portion C. As shown in the optical members of the second and third embodiments, the diffusion portion A ) Or in the light collecting portion C.

The optical fiber 153 is vertically disposed with respect to the rear surface of the optical member 150.

The optical fiber 153 has a cylindrical shape having a predetermined thickness, and is formed of a medium different from the diffusion portion A and the light collection portion C, and a gas having a low refractive index such as air is inserted therein.

The optical fiber 153 extends from one side of the optical member 150 to the other side and is regularly provided, and the thickness and the length may be changed depending on the size of the optical member 150. In addition, although not shown, the optical fiber 153 may be randomly provided in the optical member 150 or may be disposed to have a smaller size than the illustrated optical fiber 153.

The optical fiber 153 refracts the light having an inclination of 7 degrees or more with respect to the rear surface of the diffuser A by Snell's law to condense the light directly under the condenser C.

On the other hand, the optical fiber 153 reflects light having an inclination of less than 7 degrees with respect to the rear surface of the diffuser A at the interface between the optical fiber 153 and the diffuser A by Snell's law. .

When the optical fiber 153 is formed on the optical member 150, the diffusion part A and the light collecting part C are integrally formed on the side surfaces of the diffusion part A and the light collecting part C. This is to minimize the light lost.

The light loss means that light having an angle of less than 7 degrees with respect to the back side of the diffuser A is lost to the side surface of the optical member 150 through the path of the light passing through the diffuser A. FIG.

The light having an angle of less than 7 degrees is finally reflected by using the principle of refraction of light generated at the interface between two media having different refractive indices, thereby improving light loss propagating to the side surface of the optical member 150. .

Therefore, the optical member 150 according to the first embodiment of the present invention can reduce the unit cost by integrally forming the diffusion portion A and the light collecting portion C, and the diffusion portion A and the light collecting portion ( A plurality of optical fibers 153 are provided between C) to improve the optical loss which has been caused by the problem of the integrated optical member 150.

2A and 2B illustrate an optical path in an optical fiber included in an optical member according to an embodiment of the present invention by Snell's law.

As shown in FIGS. 2A and 2B, one optical fiber 153 contains a gas 157 such as air having a lower refractive index than a polymer material.

Referring to FIG. 2A, the light? Passing through the optical fiber 153 has an arbitrary incident angle θ ₁ with respect to the tangential direction H ₁ of the optical fiber 153.

The incident angle θ ₁ has an angle of less than 7 degrees based on the tangential direction H ₁ .

The incident angle θ ₁ is reflected by Snell's law at the same reflection angle θ ₂ as the incident angle θ ₁ at the interface of the optical fiber, which is a medium having a different refractive index.

On the other hand, referring to Figure 2b, the light (→) passing through the optical fiber 153 is a random angle of incidence (θ ₃ ) from the normal (l ₁ ) perpendicular to the tangential direction (H ₂ ) of the optical fiber 153 )

The incident angle θ ₃ has an angle of 7 degrees or more based on the tangential direction H ₂ .

The angle of incidence light having a (θ ₃₎ is refracted by the first refraction angle (θ ₄₎ any greater than the incident angle (θ _3), by the Snell's law while passing through the inside air-optical fiber 153 having a lower refractive index.

The refracted light has an arbitrary exit angle θ ₅ from the normal line l ₂ perpendicular to the tangential direction H ₂ , and passes through the optical fiber 153 and according to Snell's law, is refracted at any second flexion angle θ ₆ greater than θ ₅ ).

3 is an exploded perspective view illustrating an edge type backlight assembly according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the edge type backlight assembly 200 of the present invention includes a light source 210 disposed at one side of the bottom case 290 and the bottom case 290 to emit light, and the light source 210. A light guide plate 230 disposed on one side of the light guide plate, a reflective plate 270 disposed on the rear surface of the light guide plate 230, and an optical member 250 disposed on the front surface of the light guide plate 230. It is provided.

The light source 210 may be formed of any one or at least one of a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a light emitting diode (LED).

Although not shown in detail, the optical member 250 includes a diffusion unit for diffusing light and a light collecting unit for condensing light. The optical member 250 may further include a protection part that protects the light collecting part.

The optical member 250 further includes a plurality of optical fibers 253 to prevent light loss. The optical fiber 253 may be provided between the diffusion part and the light collecting part, or may be provided in the diffusion part or the light collecting part.

The optical fiber 253 has a cylindrical shape having a predetermined thickness, and is formed of a medium different from the diffusion part and the light collecting part, and a gas having a low refractive index such as air is inserted therein.

The optical fiber 253 refracts the light having an inclination of 7 degrees or more with respect to the rear surface of the diffusion part by Snell's law to condense the light directly under the light collecting part.

On the other hand, the optical fiber 253 reflects light having an inclination of less than 7 degrees with respect to the rear surface of the diffuser at the interface between the optical fiber 253 and the diffuser by Snell's law.

As such, the optical member 250 applied to the edge type backlight assembly 200 may be easily assembled by the diffusion part and the light collecting part, thereby reducing the unit cost. In addition, the optical member 250 may be provided with a plurality of optical fibers 253 therein to condense and reflect the light lost to the side surface caused by the problem of the integrated optical member 250 to prevent the luminance decrease.

Figure 4 is an exploded perspective view showing a direct backlight assembly according to an embodiment of the present invention.

As shown in FIG. 4, the direct type backlight assembly 300 of the present invention includes a plurality of light sources 310 disposed on the bottom case 390 at predetermined intervals and on a rear surface of the light source 310. The reflective plate 370 and the optical member 350 disposed on the front surface of the light source 310.

The bottom case 390 may be provided with a predetermined space therein, and the reflective plate 370 may be attached to an inner surface of the bottom case 390.

The light source 310 may be fixed to the bottom case 390 in the inner space of the bottom case 390.

The light source 310 may be formed of any one or at least one of a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a light emitting diode (LED).

The optical member 350 includes a diffuser for diffusing light and a light condenser for condensing light.

The optical member 350 further includes a plurality of optical fibers 353 to prevent light loss. The optical fiber 353 may be provided between the diffusion part and the light collecting part, or may be provided in the diffusion part or the light collecting part.

The optical fiber 353 has a cylindrical shape having a predetermined thickness and is formed of a medium different from the diffusion part and the light collecting part, and a gas having a low refractive index such as air is inserted therein.

The optical fiber 353 collects light by refracting light having an inclination of 7 degrees or more with respect to the rear surface of the optical member 350 by Snell's law.

On the other hand, the optical fiber 353 reflects light having an inclination of less than 7 degrees with respect to the rear surface of the optical member 350 at the interface of the optical fiber 353 by Snell's law.

The optical member 350 applied to the direct backlight assembly 300 as described above may be easily formed by the diffusion part and the light collecting part, thereby reducing the unit cost.

The optical member 350 having the above-described advantages is provided with a plurality of optical fibers 353 to collect and reflect the light lost to the side which has been raised due to the problem of the optical member 350 in which the diffuser and the condenser are integrally formed. It is possible to prevent the lowering of the brightness.

As described above, the optical member illustrated in FIGS. 1A to 4 may be formed of an optical fiber, but is not limited thereto. The optical member may be formed of a material having a higher refractive index than the diffuser and the condenser.

In the above description, the optical members 150, 250, and 350 are applied to the backlight assembly for the liquid crystal display device. However, the optical member of the present invention includes an optical fiber as an optical compensation means for preventing light loss, The unit and the light collecting portion may be integrally formed and applied to any product or device that requires the use of diffusing and condensing.

As described above, the present invention may include a plurality of optical fibers inside the optical member in which the diffuser and the condenser are integrally formed, thereby preventing light loss of the side surface that may occur in the integrated optical member, thereby improving light efficiency. .

In addition, in the present invention, since the diffusion part and the light collecting part are integrally formed, when the diffusion part and the light collecting part are integrally formed, the present invention can be easily assembled and the unit cost can be reduced.

Those skilled in the art through the above description will be capable of various changes and modifications without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (17)

A diffusion unit for diffusing the incident light; A condenser condensing light diffused from the diffuser; And A light compensating part disposed between the light converging part and the diffusing part; The optical compensation unit has a cylindrical shape and a plurality of optical fibers made of a medium different from at least one of the diffusion portion and the light collecting portion; It includes a gas inside the optical fiber, The diffusing part and the light collecting part are higher than the refractive index of the substrate. A diffusion unit for diffusing the incident light; A condenser condensing light diffused from the diffuser; And A light compensating unit disposed in any one of the diffusion unit and the light collecting unit; The optical compensation unit has a cylindrical shape and a plurality of optical fibers made of a medium different from at least one of the diffusion portion and the light collecting portion; It includes a gas inside the optical fiber, The diffusing part and the light collecting part are higher than the refractive index of the substrate. 3. The method according to claim 1 or 2, The diffusing part, the light collecting part, and the light compensating part are integrally formed. delete delete The method of claim 1, The plurality of optical fibers are arranged in parallel from one side to the other side, or randomly disposed optical member. delete delete A light source disposed at one side to emit light; A light guide plate disposed on a side of the light source to convert the light into a surface light source; And A diffusion part disposed on the front surface of the light guide plate to diffuse light, a light collecting part to collect light, and a light compensating part to change an optical path; The optical compensation unit has a cylindrical shape and a plurality of optical fibers made of a medium different from at least one of the diffusion portion and the light collecting portion; It includes a gas inside the optical fiber, And the diffusion part and the light collecting part include an optical member having a refractive index higher than that of the substrate. A plurality of light sources disposed on a surface to emit light; A reflector disposed on a rear surface of the light source; And A diffusion part disposed on the front surface of the light source and diffusing light, a light collecting part condensing light, and a light compensating part for changing an optical path, The optical compensation unit has a cylindrical shape and a plurality of optical fibers made of a medium different from at least one of the diffusion portion and the light collecting portion; It includes a gas inside the optical fiber, And the diffusion part and the light collecting part include an optical member having a refractive index higher than that of the substrate. 11. The method according to claim 9 or 10, The diffuser, the light collecting unit and the light compensating unit is formed integrally. 11. The method according to claim 9 or 10, And the light compensating part is disposed in any one of the diffusing part and the condensing part. 11. The method according to claim 9 or 10, And the light compensating part is disposed between the diffusing part and the condensing part. delete 11. The method according to claim 9 or 10, The plurality of optical fibers are arranged in parallel from one side to the other side, or the backlight assembly, characterized in that arranged at random. delete delete

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