KR101225603B1 - Back Light Unit within Flexible Light guide plate - Google Patents

Abstract

The present invention relates to a backlight unit, and more particularly includes a flexible light guide plate made of a flexible material provided in a structure that penetrates the LED mounted on the printed circuit board and the receiving groove for receiving the LED, the printed circuit The substrate is implemented in a structure that is divided into a unit substrate containing one or more LEDs.
According to the present invention, a light guide plate having a flexible structure, the LED is divided into a printed circuit board consisting of a unit substrate to implement a structure of a backlight unit that is easy to bend and bend according to the application, shape shape is free, heat resistance Due to the mechanical strength, high transparency, and low expandability, there is an effect of providing a backlight unit that ensures safe reliability such as vibration and thermal shock.

Description

Backlight Unit within Flexible Light guide plate

The present invention relates to a backlight unit having flexible characteristics.

The backlight unit illuminates the light evenly so that the display image can be seen on the back of the LCD which cannot emit light. The light guide plate is a component that performs the brightness and uniform illumination of the backlight unit and is emitted from the light source (LED). It is one of the plastic molded lenses that uniformly transmits light to the entire LCD surface.

FIG. 1A illustrates a structure of a side type backlight unit, and FIG. 1B illustrates a backlight unit of a direct type structure. In any structure, the light guide plate 20 may be provided to guide the light emitted from the light source 10 to the front, and may include a structure including the reflective pattern 30.

In particular, in the case of BLU which uses LED as a light source, it is made of a direct type or an edge type (side type), and the direct type has a disadvantage of thick thickness and the edge type (side type) is impossible to local dimming. It also has the disadvantage of thickening the bezel. In addition, currently used LED BLU is a hard material due to the use of a floating (hard) material, a problem that is vulnerable to vibration and heat.

The present invention has been made to solve the above problems, an object of the present invention is to include a light guide plate of a flexible structure, the LED is divided into a printed circuit board consisting of a unit substrate is easy to bend, bend according to the application The implementation of the structure of the backlight unit is free to implement the shape, and having a heat resistance, mechanical strength, high transparency, low expansion properties to provide a backlight unit that is secured in a stable reliability, such as vibration and thermal shock.

As a means for solving the above problems, the present invention, the LED is mounted on a printed circuit board; A flexible light guide plate made of a flexible material having a structure through which the receiving groove for accommodating the LED is penetrated; The printed circuit board includes a backlight unit that is dividedly arranged into a unit substrate including one or more LEDs. Make it available.

In addition, a first air gap between the LEDs accommodated in the accommodation grooves may be formed.

In addition, the separation space may be implemented in the range of 0.001um ~ 50um width.

In addition, a reflective film may be further provided on the printed circuit board, and a second separation space may be formed between the reflective film and the light guide plate.

In addition, the light guide plate according to the present invention may include one surface and the other surface facing the one surface, and an optical pattern for adjusting the light emission distribution of the LED may be implemented on the one surface or the other surface.

In this case, an optical pattern having an intaglio structure may be implemented on the other surface of the light guide plate, and the optical pattern of the intaglio structure has a first density pattern region and a second density pattern region having a higher pattern density than the first density pattern region. The first density pattern region may be formed in a region close to the light exit surface of the LED.

In addition, an optical pattern having an embossed structure may be implemented on one surface of the light guide plate, and the optical pattern of the embossed structure may include a third density pattern region and a fourth density pattern region having a higher pattern density than the third density pattern region. The fourth density pattern region may be disposed in an area close to the light exit surface of the LED.

The LED used in the backlight unit according to the present invention may apply a side view type LED, and further, at least one optical sheet of a diffusion sheet, a prism sheet, and a DBEF stacked on one surface of the light guide plate. It can be formed into a structure containing more.

According to the present invention, a light guide plate having a flexible structure, the LED is divided into a printed circuit board consisting of a unit substrate to implement a structure of a backlight unit that is easy to bend and bend according to the application, shape shape is free, heat resistance Due to the mechanical strength, high transparency, and low expandability, there is an effect of providing a backlight unit that ensures safe reliability such as vibration and thermal shock.

In particular, the structure having the air gap in the flexible light guide plate can remove the hot spots, to reduce the thickness of the entire product, it is also possible to efficiently implement local dimming (local dimming).

FIG. 1A illustrates a structure of a side type backlight unit, and FIG. 1B illustrates a backlight unit of a direct type structure.
2 is a cross-sectional conceptual view showing the structure of a backlight unit according to the present invention.
3 is an enlarged conceptual view for explaining in detail the separation space of the backlight unit according to the present invention.
4 and 5 are exemplary views showing an example of the shape of the optical pattern formed on one surface or the other surface of the light guide plate.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description with reference to the accompanying drawings, the same reference numerals denote the same elements regardless of the reference numerals, and redundant description thereof will be omitted. Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

2 is a cross-sectional conceptual view showing the structure of a backlight unit according to the present invention.

Referring to the drawings, the backlight unit according to the present invention includes a LED 120 mounted on the printed circuit board 110, and is provided with a receiving groove 140 for accommodating the LED 120. It may be configured to include a flexible light guide plate 130 made of a material.

In particular, the printed circuit board 110 according to the present invention is not a structure in which a plurality of LEDs are mounted on one substrate, but as shown, divided into unit boards including one or more LEDs 120. It is desirable to be arranged to engage with the flexibility of the light guide plate to implement the flexible characteristics of the entire backlight unit.

In addition, the backlight unit according to the present invention may further include one or more optical sheets of the diffusion sheet 150, the prism sheet 160, and the DBEF 170 stacked on one surface of the light guide plate 130. have.

The LED 120 may use a side view LED in which the emission surface 121 of the light is implemented in the sidewall direction of the receiving groove 140, that is, the direction of the light emitted from the LED light source 130. It is possible to use a light source having a structure that does not go straight to the upper portion but emits toward the side.

In addition, the printed circuit board 110 on which the LED 120 is mounted is formed as a unit substrate that is dividedly disposed on the lower surface of the light guide plate, and the reflective film 111 is formed on the upper surface of the printed circuit board 110. ) Can be stacked.

The light guide plate 130 may be formed of a material having excellent light transmittance having a flexible (flexible) characteristic to ensure flexibility basically, the receiving groove 140 in the inner direction on the other surface corresponding to one surface of the light guide plate It is provided, to be coupled to the structure in which the above-described LED 120 is inserted into the receiving groove 140.

As an example of the material constituting the light guide plate 130, in the construction of PMMA, which is a polymer material of MMA (Methyl Metha Acryl) material, a rubber material or a silicone material having the same level of flexibility may be used. . More specific examples include polyesters, amorphous polyesters, polyarylates, polycarbonates, polyamides, polyetheramides, polyamides- Polyamide-imides, polyimides, polyetherimides, cyclic olefin polymers, impact-modified polymethacrylates, polyacrylates ), Polyacrylonitrile, polystyrenes, polyethers, cellulosics, sulfur-containing polymers, or two or more polymers Polymeric materials including blends or alloys or copolymers thereof can be used.

In addition, as shown in FIG. 2, a first air gap between the LEDs 120 accommodated in the accommodation groove 140 may be formed, and a space (second second) forming such an air gap may be formed. The separation space may be formed between the reflective film 111 and the other surface of the light guide plate 130. The presence of such spaces causes problems of vibration and heat deformation due to heat generation of the LED when using a conventional light guide plate having a hardened structure such as PMMA, and in particular, a hot spot phenomenon occurs in a light guide plate that is implemented by inserting an LED. This causes heat deformation in the light guide plate on the upper side of the LED. In order to prevent this, in the past, a light shielding film for light shielding was formed or an additional configuration such as stacking of light sheets was inserted. It is possible to secure the reliability of the deformation. A-gap according to the present invention can be implemented within the range of 0.001㎛ ~ 2mm, the separation space is implemented in the range of 0.001㎛ ~ 50㎛ width in order to minimize the light leakage phenomenon in consideration of the orientation angle of the LED More preferably.

3 is an enlarged conceptual view for explaining this separation space in more detail.

As shown, the side emitting type LED 120 includes an LED chip 121 and a fluorescent material 122, and emits light in a lateral direction, in which case the receiving groove 140 of the light guide plate 130 It is preferable to have a constant space (A) with the side wall portion of the). The presence of such spaces has the advantage of controlling the distribution of light to suppress hot spots and to improve the light uniformity.

In particular, on one side and the other side of the light guide plate according to the present invention can be implemented an optical pattern for adjusting the light emitting distribution of the LED.

That is, the optical pattern of the intaglio structure may be implemented on the other surface of the light guide plate which is the surface in contact with the reflective film 111 in the structure of FIG. A second density pattern region having a higher pattern density than the first density pattern region may be formed, and the first density pattern region may be disposed in an area close to the light exit surface of the LED.

Referring to FIG. 4A, the light guide plate 130 may process the receiving groove 140 in a structure that penetrates the light guide plate through mechanical processing, and the width of the receiving groove 140 is the LED. It is preferable to form wider than the width of. In addition, it is more preferable that a first density pattern region Y1 and a second density pattern region Y2 having a higher pattern density than the first density pattern region are formed on the other surface of the light guide plate in contact with the printed circuit board.

In addition, the optical patterns 131 and 132 may be implemented on the other surface (lower surface) of the light guide plate of the backlight unit according to the present invention. Specifically, that is, the optical pattern is implemented on the other surface (lower surface) of the light guide plate 130, but the optical pattern is preferably formed on the surface of the region where the receiving groove is not formed.

Specifically, on the other surface of the light guide plate 130, a first density pattern region Y1 and a second density pattern region Y2 having a higher pattern density than the first density pattern region are formed, in particular, the first density. More preferably, the pattern region is disposed in an area close to the light exit surface of the LED. In this case, the first and second density pattern regions may be implemented as an overlapping structure or an independent arrangement of independent patterns of the intaglio structure.

That is, as shown in (b) and (c) of FIG. 4, the first and second density pattern regions of the light guide plate 130 have a cross-sectional shape having various cross-sectional shapes (semicircles) with an intaglio structure in the surface-inward direction of the light guide plate. , Ellipses, irregular shapes, etc.), and in one embodiment according to the present invention, a polygonal pyramid pattern or a hemispherical pattern may be implemented. In particular, the first density pattern region Y1 may improve the light extraction efficiency of the light emitted from the LED, thereby improving the uniformity of light, and the second density pattern region Y2 may be relatively the first density pattern. It is implemented in a pattern of higher density than the area to improve the light diffusion and scattering.

In addition, one surface (upper surface) of the light guide plate according to the present invention includes a third density pattern region X1 and a fourth density having a pattern density higher than that of the first density pattern region, having a pattern formed of a protrusion structure having an embossed structure. The pattern region X2 may be formed. In particular, in this case, it is preferable that the fourth density pattern region is disposed near the light exit surface of the LED.

In addition, as shown in FIGS. 4B to 5C, the optical patterns constituting the third and fourth density pattern regions X1 and X2 overlap the protruding patterns of a plurality of relief structures. Or may be implemented independently. For example, in the case of the second density pattern region X2, a pattern having a density higher than that of the first density pattern region X1 should be implemented. Protruding patterns of a plurality of relief structures may be formed at denser intervals, or It may be formed by adjusting the density of the pattern by forming a part of the protruding pattern to overlap.

In particular, in this case, it is more preferable that the fourth density pattern region is disposed near the light exit surface of the LED. It is more preferable that the fourth density pattern region X2 is formed near the emitting surface of the LED light, and the third density pattern region X1 is formed near the emitting surface of the LED light.

This is because the fourth density pattern region X1 formed on the upper surface of the light guide plate is embodied in a high density pattern arrangement or overlapping pattern, and is disposed close to the LED light emitting unit to diffuse or scatter a lot of strong light incident. Thus, the effect of reducing the formation of hot spots can be realized. In addition, the fourth density pattern region X2 is formed on the surface of the light guide plate in the vertical upper direction of the position where the accommodating groove is formed, and is located within one fifth of the first distance d1 to the neighboring accommodating groove. It is preferred to be implemented. More preferably, the formation limit point of the fourth density pattern is formed at a distance X3 within 10 mm from the light exit surface of the LED to remove the occurrence of hot spots. On the other hand, in the above-described third density pattern region X1, a single structure that independently forms the protrusion pattern of the above-described relief structure is formed to lower the pattern density to transmit the emitted light to a far distance and to extract light efficiency. It can be promoted to improve the uniformity of the light.

The structure of the backlight unit according to the present invention as described above, in the conventional backlight unit using an LED as a light source to solve the disadvantages of the direct type and the disadvantage of the edge type, taking advantage of each of the thin thickness, local dimming (local dimming) Efficiency, thin bezel implementation and hot spot removal are possible, and the flexible features make it stable to vibration and thermal shock, and the shape can be freely deformed for general applications. Will be implemented.

In addition, it is possible to improve the light extraction efficiency by adjusting the density and shape of the optical pattern formed on the surface of the light guide plate to improve the uniformity of the light.

In the foregoing detailed description of the present invention, specific examples have been described. However, various modifications are possible within the scope of the present invention. The technical idea of the present invention should not be limited to the embodiments of the present invention but should be determined by the equivalents of the claims and the claims.

110: printed circuit board
120: LED
130: light guide plate
140: receiving home
150: diffusion sheet
160: prism sheet
170: DBEF

Claims (12)

An LED mounted on a printed circuit board;
A flexible light guide plate made of a flexible material having a structure in which a receiving groove for receiving the LED penetrates; And
It includes a reflective film formed between the printed circuit board and the light guide plate,
The printed circuit board is divided into a unit board including one or more LEDs,
A first air gap is formed between the LEDs accommodated in the accommodation grooves.
And a second separation space is formed between the reflective film and the light guide plate.
delete The method according to claim 1,
The width of the first separation space or the second separation space is formed of 0.001㎛ ~ 50㎛, the backlight unit.
delete delete The method according to claim 1,
The light guide plate includes one surface and the other surface opposite to the one surface,
The backlight unit having an optical pattern for controlling the light emission distribution of the LED on one side or the other side.
The method of claim 6,
On the other side of the light guide plate,
The backlight unit is implemented with an intaglio optical pattern.
The method of claim 7,
The optical pattern of the intaglio structure,
A first density pattern region and a second density pattern region having a higher pattern density than the first density pattern region are formed.
And the first density pattern region is disposed in an area close to the light exit surface of the LED.
The method of claim 6,
On one surface of the light guide plate,
Backlight unit embossed optical pattern is implemented.
The method according to claim 9,
The optical pattern of the relief structure,
A third density pattern region and a fourth density pattern region having a higher pattern density than the third density pattern region are formed,
And the fourth density pattern area is disposed in an area close to the light exit surface of the LED.
The method according to claim 1,
The LED is a backlight unit (side view type) LED.
The method of claim 11,
The backlight unit further comprises at least one optical sheet of a diffusion sheet, a prism sheet, DBEF stacked on one surface of the light guide plate.

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