KR101341418B1 - Direct-lighting type backlight unit for increasing the light directional angle of led - Google Patents

Abstract

The present invention relates to a direct type backlight device capable of improving the light directing angle of a light emitting diode by using a shape of a reflective sheet. The direct type backlight device according to an embodiment of the present invention has grooves formed at regular intervals. Cover bottom; An LED light source in which LED packages are arranged at predetermined intervals on the PCB substrate; A reflection sheet having a groove corresponding to the groove of the cover bottom, and having a hole formed at the bottom of the groove to expose the LED packages; A diffusion plate for diffusing light generated from the LED light source and light reflected from the reflective sheet; And optical sheets; characterized in that it comprises a.

Description

DIRECT-LIGHTING TYPE BACKLIGHT UNIT FOR INCREASING THE LIGHT DIRECTIONAL ANGLE OF LED}

The present invention relates to a backlight device, and more particularly, to a direct type backlight device capable of improving the light directing angle of a light emitting diode by changing the shape of a reflective sheet.

The backlight device used in the liquid crystal display device uses a light emitting diode (LED) as a light source, and is classified into a direct type or side type backlight device according to the arrangement of the light sources.

On the other hand, as the price competition intensifies in recent years, research on low-cost type that can reduce the price even in a backlight device is actively conducted. In the low-cost direct-direct LED-based backlights currently produced, various efforts have been made to reduce the quantity of LEDs to reduce material costs and power consumption. However, when reducing the number of LEDs in this way, there is a problem that the LED light reflecting (Mura) phenomenon occurs because the luminance difference between the portion where the LED is located and the peripheral portion is severe. In order to solve this problem, a technique of increasing a thickness of a backlight or applying a light diffusion lens to an upper end of an LED is disclosed.

1 is a plan view showing a part of the cover bottom and the reflective sheet of the LED backlight according to the prior art, Figure 2 is a longitudinal cross-sectional view showing in detail the structure of the light source unit which is a main part of Figure 1, a cross-sectional view in the A-A direction of FIG.

1 and 2, in the conventional LED backlight 10, the PCB substrate 13a on which the LED package 13b is mounted is disposed on the cover bottom 11 at a predetermined interval, and then the LED package 13b is disposed. The light emitted from the LED package 13b is passed through the diffuser plate 14 and the optical sheets 15 by covering the reflective sheet 12 on which the holes 12a for exposing are formed. At this time, the LED light source 13 includes a separate light diffusing lens 13c disposed on the LED package 13b to eliminate the LED shining phenomenon. The light diffusing lens 13c controls the light of the point light source of the LED package 13b to be emitted at a wide directing angle, thereby eliminating the LED portion of the LED package 13b and the LED illuminating phenomenon caused by the LED package, thereby improving the appearance of the backlight. do.

However, in the light diffusion lens applied to the upper end of the LED package, an expensive transparent or translucent resin to which a diffusion agent is added is used, thereby increasing the manufacturing cost of the backlight device according to the expensive material cost, and adding a process of assembling the light diffusion lens. There is a problem that the manufacturing process is complicated as it is performed.

The present invention has been proposed to solve the above problems, an object of the present invention is to diffuse the light generated in the LED package by using a diffuse reflection or refraction through the change of the shape of the reflective sheet to eliminate the light diffusing lens to a wide direct angle It is an object of the present invention to provide a low-cost direct-type backlight device capable of improving the appearance while reducing manufacturing costs.

In order to achieve the above object, the direct type backlight device of the present invention includes a cover bottom in which an optical seating groove is formed at a predetermined interval; An LED light source disposed in the light source seating groove of the cover bottom; And a reflection sheet having a groove corresponding to the light source ophthalmic groove of the cover bottom, and having a reflector for upwardly diffused reflection of light from the LED light source near the mounting groove.

The reflector may include an inclined surface for diffusely reflecting light emitted from the LED light source, and protrusions or beads formed on the inclined surface.

In addition, the reflector may have an inclined surface protruding in the shape of a concave groove protruding from the groove formed in the reflective sheet, and the concave groove inclined surface may be formed with protrusions or beads for diffusely reflecting outgoing light.

In addition, the reflector has a plurality of mountain-shaped protrusions, a hole is formed in the peaks of the protrusions for exposing the LED package, the protrusion is a height (h) of 0.1 ~ 20mm, from the base to the LED package The interval x is 0.1 to 20 mm, and the vertical inclination angle δ may be formed at 1 to 90 degrees.

In addition, the reflector may be formed by a process of forming the reflective sheet by any one of vacuum molding, hot press molding, and injection molding using a high reflection resin, or by attaching the reflective sheet to a press-shaped cover bottom.

In addition, the direct type backlight device further includes a diffusion plate or an optical sheet for diffusing the light generated from the LED light source and the light reflected from the reflective sheet.

According to the present invention, the manufacturing cost can be reduced by eliminating the light diffusing lens of the LED package in the low-cost direct-type backlight device, and at the same time, the reflection angle is refracted or refracted by the shape change of the reflecting sheet to reduce the direction angle. By making it wider, the appearance of a backlight device can be improved.

1 is a plan view showing a part of the cover bottom and the reflective sheet of the LED backlight according to the prior art,
2 is a longitudinal cross-sectional view showing in detail the light source unit structure which is a main part of FIG.
3 is a perspective view showing a part of a cover bottom and a reflective sheet of a direct type LED backlight according to a first embodiment of the present invention;
4 is a longitudinal cross-sectional view showing in detail the light source unit structure that is the main part of FIG.
5 is a plan view showing a part of a cover bottom and a reflective sheet of an LED backlight according to a second embodiment of the present invention;
6 is a longitudinal cross-sectional view showing in detail the light source unit structure that is the main part of FIG.
7 is a plan view showing a part of a cover bottom and a reflective sheet of an LED backlight according to a third embodiment of the present invention; and
FIG. 8 is a longitudinal cross-sectional view showing in detail a light source part structure that is a main part of FIG. 7.

The technical problems achieved by the present invention and the practice of the present invention will be more clearly understood by the preferred embodiments of the present invention described below. The following examples are merely illustrated to illustrate the present invention and are not intended to limit the scope of the present invention.

3 is a perspective view illustrating a part of a cover bottom and a reflective sheet of a direct type LED backlight according to a first embodiment of the present invention, and FIG. 4 is a longitudinal cross-sectional view illustrating a light source part structure, which is a main part of FIG. 3, in detail. It is sectional drawing of BB direction.

The direct type LED backlight device 100 according to the first embodiment of the present invention includes a cover bottom 110 in which grooves 110a are formed at a predetermined interval, as shown in FIGS. 3 and 4. ), An LED light source 130 in which the LED packages 134 are arranged at predetermined intervals on the PCB substrate 132, and grooves 122 corresponding to the grooves 110a of the cover bottom 110 are formed. On the bottom surface of the 122, a reflection sheet 120 having a hole for exposing the corresponding LED package 134 is formed, and light generated from the LED package 134 and light reflected from the reflection sheet 120 are diffused. Diffusion plate 140 and the optical sheet 150 for controlling the optical characteristics of the light emitted from the diffusion plate 140. Here, the groove 122 of the reflective sheet 120 may be formed by a similar process such as vacuum molding, hot press molding, injection molding using a high reflection resin, and the shape reflective sheet by processing a shape on the cover bottom 110. It can be made in the process of attaching. In addition, a diffuse reflection pattern 124 such as a projection or a bead is formed on the groove inclined surface 122a to diffusely reflect the emitted light, thereby increasing the directing angle of the light generated by the LED package 134.

Specifically, the groove 110a is formed at a predetermined interval on the cover bottom 110, and the PCB substrate 132 on which the LED package 134 is mounted is disposed on the groove 110a of the cover bottom 110. . In addition, the reflective sheet 120 having the hole for exposing the LED package 134 and the groove 122 corresponding to the groove 110a formed in the cover bottom 110 is formed on the PCB substrate 132 and the cover bottom ( 134 is disposed to cover.

Here, since the LED package 134 is exposed through the hole formed in the reflective sheet groove 122, the light emitted from the LED package 134 is reflected directly or on the inner surface of the groove 122, the diffusion plate 140 and the optical The sheet 150 is passed through. At this time, the light having a narrow angle of directivity emitted from the LED package 134 is scattered by reflected light by the diffuse reflection pattern 124 formed on the inclined surface 122a of the reflective sheet groove 122 to have a wide angle of directivity. For example, the light emitted from the LED package 134 at a predetermined direction angle α according to the first embodiment of the present invention passes through the groove 122 of the reflective sheet 120 and is approximately 1.25 times wider. alpha = alpha x 1.25).

5 is a plan view showing a part of the cover bottom and the reflective sheet of the LED backlight according to the second embodiment of the present invention, Figure 6 is a longitudinal cross-sectional view showing in detail the light source portion structure of the main part of Figure 5, CC direction of FIG. It is a cross section of.

As shown in FIGS. 5 and 6, the direct type LED backlight device 200 according to the second embodiment of the present invention has a cover bottom 210 provided with a light source mounting groove 201a and a PCB substrate 232. A plurality of LED packages 234 are mounted at predetermined intervals so that the plurality of LED light source 230 and the cover bottom 210-is disposed in the seating groove 210a, and corresponding to the arrangement position of the LED package 234 Protruding concave grooves 222 are formed in the center of each protruding concave groove 222, the reflection sheet 220 is formed in the hole for exposing the LED package 234 and the LED package 234 is generated It includes a diffusion plate 240 for diffusing the light reflected from the light and the reflective sheet 220, and an optical sheet 250 for controlling the optical characteristics of the light emitted from the diffusion plate 240. In addition, a projection or bead-shaped diffuse reflection pattern 224 is formed on the inclined surface 222a of the protruding concave groove 222 of the reflective sheet 220 to emit light from the LED package 234. Increase the orientation angle At this time, the protruding concave groove 222 of the reflective sheet 220 may be formed by a similar process, such as vacuum molding, hot press molding, injection molding using a high reflection resin, the shape by processing the shape on the cover bottom 210 It may be made of a process of attaching the reflective sheet.

In detail, the PCB 232 on which the LED package 234 is mounted is disposed in the mounting groove 210a of the cover bottom 210 at a predetermined interval, and the reflective sheet on which the plurality of protruding concave grooves 222 are formed ( The 220 is disposed to cover the PCB substrate 232 and the cover bottom 210. Here, the protruding concave groove 222 of the reflective sheet 220 is formed at a position corresponding to the position of the LED package 234 disposed in the cover bottom 210, the LED package 234 in the center of the concave groove 222. Since a hole for exposing the light is formed, the light emitted from the LED package 224 is reflected directly on the inner surface of the protruding concave groove 222 and exits upward.

The light having a narrow angle of directivity emitted from the LED package 230 by the reflective sheet 220 having the structure is reflected and scattered in the diffuse reflection pattern 224 formed in the protruding concave groove 222 of the reflective sheet 220. It has a directing angle and is uniformized while passing through the diffusion plate 240 and the optical sheets 250 to eliminate the LED light phenomena. For example, according to the second embodiment of the present invention, the light emitted from the LED package 234 at a predetermined direction angle α passes through the protruding concave groove 222 of the reflective sheet 220 and is approximately 1.25 times wider. It can be enlarged to an angle α2 = α × 1.25.

FIG. 7 is a plan view showing a part of a cover bottom and a reflective sheet of an LED backlight according to a third embodiment of the present invention, and FIG. 8 is a longitudinal sectional view showing a detailed structure of a light source unit, which is a main part of FIG. It is a cross section of.

As shown in FIGS. 7 and 8, the direct type LED backlight device 300 according to the third embodiment of the present invention has a cover bottom 310 provided with a light source mounting groove 310a and a PCB substrate 332. A plurality of LED packages 334 are mounted at predetermined intervals and a plurality of LED light source 330 is disposed in the seating groove 310a of the cover bottom 310, and a plurality of protrusions 322 formed with a hole in the top Is dispersed in the reflective sheet 320, the light emitted from the LED light source 330 and the diffuser plate 340 for diffusing the light reflected from the reflective sheet 320, the light emitted from the diffuser plate 340 The optical sheet 350 for controlling the optical properties of the. Here, the protrusion 322 of the reflective sheet 320 serves to deflect the light generated from the LED package 334 to emit a wide direct angle. The protruding portion 322 of the reflective sheet 320 may be formed by a similar process such as vacuum molding, hot press molding, injection molding using a high reflection resin, and attaches a shape reflective sheet by processing a shape on the cover bottom 310. It can be made to the process.

Specifically, a PCB substrate 332 on which the LED package 334 is mounted is disposed at a predetermined interval in the seating groove 310a of the cover bottom 310, and a plurality of mountain-shaped protrusions are disposed on the reflective sheet 320. 322 is dispersed, and a hole for refracting light emitted from the LED package 334 is formed at the top of each protrusion 322. In this case, when the height of the protrusion 322 is h, the distance from the base of the protrusion 322 to the LED package 324 is x, and the vertical inclination angle of the protrusion 322 is δ.

division sign value Protrusion height h 0.1-20mm LED chip distance x 0.1-20mm Tilt angle δ 1 to 90 °

Therefore, the light having a narrow direction angle generated by the LED package 330 is refracted past the upper end of the protrusion 322 of the reflective sheet 320 to have a wide direction angle. The light having a wide angle of directivity is uniformized while passing through the diffusion plate 340 and the optical sheets 350 so that the LED shining phenomenon is eliminated. For example, the light emitted from the LED package 334 at a predetermined direction angle α according to the third embodiment of the present invention passes through the protrusion 322 of the reflective sheet 320 and is approximately 1.25 times wider. It can be enlarged to an angle α2 = α × 1.25.

As described above, the direct type backlight device using the LED of the present invention as a light source can increase the directivity angle of the light emitted from the LED package even though a light diffusing lens is not provided by changing the shape of the reflective sheet. Manufacturing costs can be reduced by reducing component count.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

100,200,300: backlight unit 110,210,310: cover bottom
120,220,320: Reflective sheet 130,230,330: LED light source
132,232,332: PCB 134,234,334: LED package
140,240,340: diffuser plate 150,250,350: optical sheet

Claims (8)

A cover bottom in which optical seating grooves are formed at regular intervals;
An LED light source disposed in the light source seating groove of the cover bottom; And
And a reflecting sheet having a groove corresponding to the light source ophthalmic groove of the cover bottom, and having a reflecting portion for diffusely reflecting the light from the LED light source near the seating groove.
The direct type backlight device, characterized in that the reflective sheet is formed by any one of vacuum molding, hot press molding and injection molding using a high-reflective resin, or by attaching the reflective sheet to the press-shaped cover bottom. . The method of claim 1, wherein the reflector,
And an inclined surface for diffusely reflecting light emitted from the LED light source, and projections or beads formed on the inclined surface. The method of claim 1, wherein the reflector,
And a sloped surface having a concave groove shape protruding near the groove formed in the reflective sheet. The method of claim 3,
Protruding concave groove inclined surface of the reflective sheet is a direct type backlight device, characterized in that the projection or bead is formed to diffuse the reflected light. The method of claim 1, wherein the reflector,
And a plurality of mountain-shaped protrusions, and the peaks of the protrusions are formed with holes for exposing the LED package. The method of claim 5, wherein the protrusion,
A direct type backlight device, characterized in that the height (h) is 0.1 to 20mm, the distance (x) from the base to the LED package is 0.1 to 20mm, and the vertical inclination angle (δ) is 1 to 90 degrees. delete 7. The method according to any one of claims 1 to 6,
And a diffuser plate or an optical sheet for diffusing the light generated from the LED light source and the light reflected from the reflective sheet.

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