KR101326666B1 - A flexible backlight unit - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a backlight unit, and more particularly, to a flexible LED backlight used as a light source of a flexible display.

The flexible LED backlight according to the characteristics of the present invention is composed of a flexible PCB substrate, a plurality of red, green, blue LEDs arranged on the PCB substrate, and a plurality of optical films located on the PCB substrate. Before attaching the optical film, it characterized in that the optical structure of the mesh (mesh type) for compensating the impact strength between the plurality of LEDs.

Description

Flexible backlight unit

1 is a perspective view schematically illustrating a configuration of a liquid crystal display device having an LED backlight unit;

2 is a perspective view schematically showing the configuration of a flexible LED backlight according to a first embodiment of the present invention,

3A to 3D, 4A to 4C, and 5A to 5B are diagrams showing a configuration example of a cluster and a form of a micro lens covering an LED.

 6A to 6C, which illustrate the configuration of a light guide layer formed on the optical structure,

7a and 7b show an optical structure according to the present invention,

8 is a cross-sectional view schematically showing the configuration of a flexible backlight according to a second embodiment of the present invention,

9 is a cross-sectional view schematically showing the configuration of a flexible backlight according to a third embodiment of the present invention,

10 is an enlarged cross-sectional view of FIG. 9K.

<Description of the symbols for the main parts of the drawings>

300: flexible backlight unit 302: PCB board

304: LED 306: Micro Lens

308: reflective layer PW: partition wall

310: optical structure 312: optical adhesive layer

314: light guide layer 316: optical film

The present invention relates to a flexible backlight unit for a liquid crystal display device, and more particularly, to a flexible backlight unit.

In general, the flexible display has a curved physical property, and can be broadly divided into three methods using a liquid crystal display, an organic light emitting diode (OLED), and an electronic ink method (e-paper).

In general, a flexible liquid crystal display device is made of plastic instead of glass to improve the warpage.

However, the OLED is a device that emits light by itself, and the electronic ink method, that is, the E-paper is a black and white image using a black and white pigment, and thus does not require a separate light source.

However, since the liquid crystal display device is not an element that emits light by itself, it is an element that requires a separate light source (hereinafter referred to as "backlight").

In particular, there is an effort to implement this as a flexible display in a TFT-LCD method having the highest demand in the future, but studies on the backlight to support this have been insufficient.

Flexible backlight has high competitiveness compared to other methods in that it can manufacture a flexible display utilizing the process and advantages of the TFT-LCD which has a high occupancy as it is, and thus can be used in the flexible liquid crystal display device. Active research is underway to develop flexible backlights.

1 is a cross-sectional view illustrating a configuration of a flexible LCD including a flexible backlight according to the related art.

As illustrated, a conventional flexible liquid crystal display (FLCD) includes a flexible liquid crystal panel 10 and a flexible backlight 20.

The flexible liquid crystal display (FLCD) includes an array substrate B1 and a color filter substrate B2 made of a plastic material, and the array substrate B1 is formed on a surface of the transparent first substrate 22 made of a flexible plastic material. A plurality of gate lines 12 and data lines 24 intersecting horizontally, and the gate and data lines 12 for each of the plurality of pixel regions P defined by the two lines 12 and 24 intersecting. And a switching element T for receiving a gate signal and a data signal from the 24, and a pixel electrode 17 for receiving a pixel voltage from the switching element T.

The color filter substrate B2 includes red, green, and blue color filters 7a, 7b, and 7c sequentially arranged on the surface of the transparent second substrate 5 made of a flexible plastic material, corresponding to each pixel area P. In addition, a black matrix 6 as a light blocking means is formed corresponding to the light leakage region between the pixel regions P.

In addition, a transparent common electrode 18 is formed on the entire surface of the substrate 5 including the black matrix and the color filters 6, 7a, 7b, and 7c.

In this case, as described above, the first and second substrates 22 and 5 may be made of a transparent material and a plastic material having flexibility, so that the liquid crystal panel 10 may have flexible characteristics.

The backlight unit 20 is formed under the liquid crystal panel 10. Since the conventional CCFL or EEFL is made of a long glass tube, there is a limit in obtaining flexible characteristics. (26) is used as the light source.

In detail, by arranging the LEDs 26 on the flexible PCB substrate 24 in a predetermined form, the LEDs 26 may be used as a light source of the backlight unit 20.

In this case, the backlight unit 20 may further include an optical member 24 (optical film) positioned above the PCB substrate 26 on which the LEDs 26 are arranged, thereby improving light efficiency.

The conventional flexible LED backlight described above is merely a proposal of the most basic structure, and in order to increase the practical applicability, it is necessary to develop a technology that can have more flexible characteristics while further improving the actual optical function and increasing the mechanical strength. There is a need for active research into this.

It is an object of the present invention to provide a flexible LED backlight unit having more flexible characteristics while improving optical efficiency and at the same time increasing mechanical strength.

To achieve the above object

-Example 1--

2 is an enlarged cross-sectional view schematically illustrating a structure of a flexible LED backlight unit according to a first embodiment of the present invention.

As shown, the flexible LED backlight unit 100 according to the first embodiment of the present invention is mounted on the front surface of the PCB substrate 102 and the PCB substrate 102 having a flexible characteristic from the bottom, and the micro lens The plurality of LEDs 104 covered with the 106 and the upper part of the PCB substrate 102 on which the LEDs 104 are configured have a mesh PW formed in each of the separation intervals of the LEDs 104. It comprises an optical structure 108 composed of, and an optical adhesive layer 110 and the light guide layer 112 and the optical member 114, the optical film 114 positioned on the optical structure 108.

In the above-described configuration, the PCB substrate 102 in which the plurality of LEDs 104 are arranged and fixed has a flexible characteristic, and a metal wiring (not shown) having excellent heat resistance and heat dissipation characteristics and bending strength is formed on the back surface. The metal wires (not shown) are patterned using a photolithography method.

In this case, the PCB substrate 102 may be a silicon or a polymer material having similar characteristics or a resin material such as epoxy, or acrylic, polycarbonate, polyester, and copolymers thereof. It is formed of a material in which a polymer material such as a glass fiber (glass fiber) is mixed to have a unique flexibility.

The reflective layer 116 is formed on the surface of the PCB substrate 102. The reflective layer 116 may be formed by applying a paint or the like having excellent reflection characteristics or by attaching a high reflective sheet.

The LED 104 covered with the microlens 106 may be composed of R, G, B LEDs, and white LEDs, and each of R, G, B LEDs, and white LEDs may be one or more than one group. It consists of a regular or irregular repeating structure of the cluster.

In addition, by applying a phosphor on the surface of the LED 104, it is possible to further improve the brightness.

In this case, the microlens 106 is intended to diffuse the light emitted from the LED 104 better.

In particular, since the LED backlight unit 100 has a plurality of LEDs 104 arranged at regular intervals, the LED backlight unit 100 appears to be very bright in the portion where the LEDs 104 are located, and the luminance is lowered in the spaced area between the LEDs 104. The difference in luminance is displayed as a blot on the screen.

Therefore, in order to minimize the luminance difference, the micro lens 106 is configured.

In this case, the microlens 106 may be manufactured to have various cross-sectional shapes such as a semicircle, a rectangle, and a triangle.

In addition, in order to include one or more LEDs, that is, it can be manufactured in a size that can include all three or four LEDs configured in a cluster unit.

Hereinafter, FIGS. 3A to 3D, 4A to 4C, and 5A to 5B are diagrams showing the configuration example of a cluster and the form of a microlens covering an LED.

3A to 3D, white, red, green, and blue LEDs are used, and three or four may be configured in a cluster unit composed of one group.

In particular, as shown in FIGS. 3A and 3C, when the three LEDs are configured as a group, the red, green, and blue LEDs 104a, 104b, and 104c are radially positioned at regular intervals. 3B and 3D, when the four LEDs are configured as a group, the red, green, blue, and white LEDs 104a, 104b, 104c, and 104d are radially positioned at regular intervals. Configure.

3A and 3B, each of the red, green, blue, and white LEDs 104a, 104b, 104c, and 104d has a semicircular cross-sectional shape but has a circular circular shape in plan view. , 106c, 106d.

In this case, the microlenses may have a spherical shape, a cone shape, or a prism shape, and may be manufactured to have various cross-sectional shapes such as a semicircle, a rectangle, and a triangle.

That is, as shown in Figs. 3C and 3D, microlenses 106a, 106b, 106c, and 106d having a semicircular cross-sectional shape but having a quadrangular shape in plan view may be formed.

In addition, as shown in FIGS. 4A to 4C, the microlenses 106e to 106g include the red and green and blue LEDs 104a, 104b and 104c constituting the first cluster CL1, or the second cluster CL2. It can be configured to a size that simultaneously covers the red and green and blue and white LED (104a, 104b, 104c, 104d) constituting the).

In addition, the plurality of LEDs forming the cluster may take a variety of arrangements, for example, as shown in Figures 5a and 5b, the red and green and blue LEDs 104a, 104b, 104c side by side, The red, green, blue, and white LEDs 104a, 104b, 104c, and 104d may be arranged side by side in one direction.

Alternatively, although not shown, it may be configured by a white LED alone, four LEDs of red, green, blue, and green in one cluster, or only four white LEDs in one cluster.

6A to 6C, the configuration of the light guide layer formed on the optical structure will be described.

6A to 6C are cross-sectional views illustrating a cross-sectional shape of a light guide layer having a plurality of optical patterns on its surface.

The light guide layer 112 according to the present invention may be formed of a polymer material having excellent ductility, excellent light transmissivity, and excellent heat resistance, for example, a material of acrylic, polycarbonate, polyester, or a copolymer of the material. In addition, the micro lens (104 of FIG. 1) described above has a function of minimizing the generation of spots due to the difference in luminance.

The optical pattern of the light guide layer 112 may be formed as an embossed or engraved prism pattern as shown in FIGS. 6A and 6B, and as shown in FIGS. 6C and 6D, an embossed or engraved dot pattern Or 154.

In addition, as shown in Figs. 6A to 6D, when the specific pattern 150, 152, 154, 156 is formed in a state in which a plurality of beads 158 having a spherical shape are included therein, when the warpage occurs, the incident state is also applied to the 휜 state. The light is diffused internally through the plurality of beads 158 so that the light propagation path is appropriately changed so that the light is emitted to the upper surface efficiently.

At this time, the above-described optical film (114 in FIG. 2) formed on the light guide layer 112 is made of acrylic, polycarbonate, polyester, etc., and similar to the light guide layer (112 in FIG. Included patterns include, for example, embossed or engraved spherical, cone, or prismatic shapes.

7A and 7B are views illustrating an optical structure according to the present invention.

As shown, the optical structures 108a and 108b have a structure in which the partition wall PW is formed in a mesh shape, and as shown in FIGS. 7A and 7B, the optical structures 108a are planarly disposed as LEDs. Openings are formed to correspond to the couple where the si) is located, and the openings may be formed of a polygon including a circle or a quadrangle.

The optical structure of the above-described type is to improve the impact strength and improve the light diffusion function by complementing the mechanical function.

This optical structure 108 must be flexible to suit the structure of the flexible backlight itself, and must be transparent and have the function of diffusing light.

To this end, the optical structure 108 may be formed of a polycarbonate-based, acrylic, or polyester-based material, it may be configured to further include a bid (bid) inside for the light diffusion function.

At this time, the characteristic partition wall (PW) constituting the optical structure 108 is located between the LED or cluster (not shown), the width of the partition wall corresponding to the separation distance between the LED or the cluster, the LED or It can be configured equal to or smaller than the separation distance between the clusters.

The above-described optical structure 108 and the light guide layer 112 of FIG. 2 are bonded through a thick optical adhesive 110 (see FIG. 2), and the optical adhesive 110 (see FIG. 2) is transparent and the optical film. Acrylic type, silicone type and its copolymer with little refractive index difference with (114 of FIG. 2) can be made into a film form, and can be produced.

Such an optical adhesive (110 of FIG. 2) has an advantage of preventing misalignment of the light guide layer and the optical structure when the PCB substrate is bent.

Through the above configuration, the flexible backlight according to the first embodiment of the present invention can be configured.

The above-described configuration is a configuration in which the LED is mounted on the upper surface of the PCB substrate, but such a configuration serves to limit the thickness of the backlight, so to solve this problem, a groove is formed in the PCB substrate and the LED is mounted. Is proposed through the second embodiment.

-Second Embodiment--

8 is a cross-sectional view schematically illustrating a configuration of the flexible backlight unit according to the second embodiment of the present invention.

As shown, the flexible LED backlight unit 200 according to the second embodiment of the present invention is a PCB substrate 202 having a plurality of grooves (H) formed in a constant shape on the front, with a flexible characteristic from the bottom, And a plurality of LEDs 204 disposed inside the grooves H and covered with the microlenses 206, and partition walls PW disposed between the LEDs 204 and having a predetermined height in a mesh form. The structure 210 includes a structure, a light guide layer 214 disposed on the optical structure 210, and a plurality of optical films 216 disposed on the light guide layer 214.

In this case, the light guide layer 214 and the optical film 216 are bonded through the optical adhesive layer 212.

In addition, in order to dissipate the heat generated by the LED 204, the metal pattern 218 is further formed on the lower portion of the PCB substrate 202 corresponding to the groove (H) where the LED 204 is located.

The PCB substrate 202 on which the LED 204 is mounted has a flexible characteristic, and is coated with a metal thin film having excellent heat and heat dissipation characteristics and bending strength.

In this case, the PCB substrate 202 may be a silicon material or a polymer material having similar properties or a resin material such as epoxy, or an acrylic, polycarbonate, polyester, and copolymers thereof. It is formed of a material in which a polymer material such as a glass fiber (glass fiber) is mixed to have a unique flexibility.

The reflective layer 208 is formed on the surface of the PCB substrate 202. The reflective layer 208 may be formed by applying a paint or the like having excellent reflection characteristics or by attaching a high reflective sheet.

At this time, the angle formed between the groove H formed in the substrate 202 and the upper surface of the PCB substrate 202 is maintained at an angle of 70 ^° or less when the vertical direction is 0.

In addition, by applying a phosphor to the surface of the LED, it is possible to further improve the brightness.

The LED 204 covered with the microlens 206 may be composed of red, green, blue LEDs, and white LEDs, as described above in the first embodiment. It consists of a regular or irregular repeating structure of clusters of one or more components.

Since the detailed configuration is the same as the configuration described in the first embodiment, a description thereof will be omitted.

 The microlens 206 is intended to diffuse the light emitted from the LED 204 better.

 In particular, since the plurality of LEDs 204 are arranged at regular intervals, the LEDs 204 appear to be very bright in the region where the LEDs 204 are located, and the luminance is lowered in the spaced area between the LEDs 204, such a difference in luminance It will appear as a spot on the screen.

Therefore, in order to minimize such luminance difference, the micro lens 206 is configured.

In this case, the microlens 206 may have a spherical shape, a cone shape, or a prism shape, and may be manufactured to have various cross-sectional shapes such as a semicircle, a rectangle, and a triangle.

As described above, the light guide layer 214 has a specific pattern (150, 152, 154, 156 of FIG. 6A), such as a prism pattern and an embossed and engraved dot pattern, and has a plurality of spherical shapes therein. When the warpage occurs by including the bead (158 in FIG. 6), the light propagating path is diffused internally through the plurality of beads (158 in FIG. 6) even when the warp state is changed. By doing so, it is possible to efficiently exit the upper surface.

The light guide layer 214 may be formed of a polymer material having excellent ductility, excellent light transmitting property, and excellent heat resistance, for example, one of acrylic, polycarbonate, and polyester, or a copolymer of the above material. Together with the micro lens described above, it has a function of minimizing spots caused by luminance difference.

At this time, the above-described optical film formed on the light guide layer 214 also includes the same optical pattern as the light guide plate.

In this case, the optical film 216 formed on the light guide layer 214 described above is made of acrylic, polycarbonate, polyester, and the like, and includes an optical pattern on the surface similar to the light guide layer 214. For example, it is an embossed or engraved spherical, conical, or prismatic shape.

The above-described mesh type optical structure 210 is to improve the impact strength and improve the light diffusion function while maintaining the flexibility of the backlight unit while complementing the mechanical function.

The optical structure 210 should be flexible to be suitable for the structure of the flexible backlight itself, and should be transparent and have the function of diffusing light.

The optical structure 210 having such a characteristic may be formed of a polycarbonate-based, acrylic-based, or polyester-based material, and may further include a bid inside the light diffusion function.

At this time, the characteristic partition wall (PW) constituting the optical structure 210 is located between the LED 204 arranged one by one or between the cluster of three or four LED group, between the LED 204 or The width of the partition wall located between the clusters may be the same as or smaller than the separation distance between the LED or the cluster.

In addition, the optical structure 210 has a shape in which openings are formed in correspondence with the couple where the LED 204 is located in a plan view, and the openings may be formed of a polygon including a circle or a quadrangle.

The optical structure 210 and the light guide layer 214 are bonded through the optical adhesive 212, the optical adhesive 212 is in the form of a paste or film, transparent and the refractive index of the optical film 216 The acrylic, silicone and copolymers thereof with little difference can be produced in the form of a film.

The optical adhesive 212 has an advantage of preventing misalignment between the light guide layer 214 and the optical structure 216 when the PCB substrate 202 is bent.

The configuration of the above-described second embodiment is a form in which the groove is formed in the PCB substrate, and the LED is mounted inside the groove, but this type does not completely fix the LED when a severe impact is applied from the outside. As it may be, a configuration for solving the problem is proposed through the following third embodiment.

  -Third Embodiment--

9 is a cross-sectional view schematically showing the configuration of a flexible backlight according to a third embodiment of the present invention.

As shown, the flexible LED backlight 300 according to the third embodiment of the present invention includes a PCB substrate 302 having a plurality of grooves H formed in a constant shape on the front and having a flexible characteristic from the bottom and In addition, a plurality of LEDs 304 disposed through the support 320 in the groove H and covered with the microlens 306, and partition walls PW disposed between the LEDs 304 and having a predetermined height are provided. The optical structure 310 having a mesh shape, a light guide layer 314 disposed on the optical structure 310, and a plurality of optical films 316 positioned on the light guide layer 314.

In this case, the light guide layer 314 and the optical structure 310 are bonded through a thick optical adhesive layer 312.

In order to dissipate heat generated by the LED 304, a metal pattern 318 is further formed under the PCB substrate 302 corresponding to the groove H in which the LED 304 is located.

The PCB substrate 302 on which the LED 304 is mounted is a substrate having flexible characteristics, and a metal thin film having excellent heat resistance and heat dissipation characteristics and bending strength is coated.

In this case, the PCB substrate 302 may be a polymer material having silicon and similar properties or a resin material such as epoxy, or an acrylic, polycarbonate, polyester, and copolymers thereof. It is formed of a material in which a polymer material such as a glass fiber (glass fiber) is mixed to have a unique flexibility.

The reflective layer 308 is formed on the surface of the PCB substrate 302. The reflective layer 308 may be formed by applying a paint or the like having excellent reflection characteristics or by attaching a high reflective sheet.

At this time, the angle formed between the groove H formed in the PCB substrate 302 and the upper surface of the PCB substrate 302 maintains an angle of 70 ^° or less when the vertical direction is 0.

On the other hand, by applying a phosphor on the surface of the LED, it is possible to further improve the brightness.

The LED 304 covered with the microlens 306 may be composed of red, green, blue LEDs, and white LEDs, and each of the clusters including one, or more than one, red, green, blue, and white LEDs. It consists of regular or irregular repeating structures.

Since the detailed configuration is the same as the configuration described in the first embodiment, a description thereof will be omitted.

The micro lens 306 is intended to diffuse the light emitted from the LED (304) better.

In particular, since the plurality of LEDs 304 are arranged at regular intervals, the LEDs 304 are displayed very brightly in the portion where the LEDs 304 are located, and the luminance is lowered in the spaced area between the LEDs 304, such a difference in luminance It will appear as a spot on the screen.

Therefore, in order to minimize such luminance difference, the micro lens 306 is configured.

In this case, the microlens 306 may have a spherical shape, a cone shape, or a prism shape, and may be manufactured to have various cross-sectional shapes such as a semicircle, a rectangle, and a triangle.

As described above, the light guide layer 314 forms a plurality of beads (not shown) having a spherical shape therein while forming a specific pattern such as a prism pattern and an embossed and engraved dot pattern. When the warpage occurs, the incident light is diffused internally through the plurality of beads (not shown) even when the warpage occurs, so that the light propagation path is properly changed so that the light exits to the upper surface efficiently. .

The light guide layer 314 may be formed of a polymer material having excellent ductility, excellent light transmissivity, and excellent heat resistance, for example, one of acrylic, polycarbonate, and polyester, or a copolymer of the material. Together with the micro lens described above, it has a function of minimizing spots caused by luminance difference.

At this time, the optical film is made of acrylic, polycarbonate, polyester, and the like, and includes an optical pattern on the surface similar to the light guide layer 314, for example, embossed or engraved spherical, cone, or prism shape will be.

The optical structure of the mesh-type described above is to improve the impact strength and improve the light diffusion function by complementing the mechanical function.

The optical structure 310 should be flexible to be suitable for the structure of the flexible backlight itself, and should be transparent and have the function of diffusing light.

The optical structure 310 having such a characteristic may be formed of a polycarbonate-based, acrylic-based, or polyester-based material, and may further include a bid inside the light diffusion function.

In this case, the partition wall forming the optical structure is located between the LEDs arranged one by one or between the cluster of three or four LED group, the width of the partition wall between the LEDs or between the clusters, the LED or It can be configured to be equal to or smaller than the distance between clusters.

In addition, the optical structure 310 has a shape in which openings are formed in correspondence with the couple where the LEDs 304 are located in a plan view, and the openings may be formed in a multi-layered shape including a circle or a quadrangle.

The optical structure 310 and the light guide layer 314 are bonded through the optical adhesive 312, the optical adhesive 312 is in the form of a paste or film, transparent and the refractive index with the optical film 316 The acrylic, silicone and copolymers thereof with little difference can be produced in the form of a film.

The optical adhesive 312 has an advantage of preventing misalignment of the light guide layer and the optical structure when the PCB substrate is bent.

10 is an enlarged cross-sectional view of the G of FIG. 9.

The illustrated figure shows the LED 304 and the support 320 supporting the LED 304, and the support 320 is formed of a polymer material having excellent optical properties, heat resistance, and mechanical strength.

"형상으로 구성되고, 상기 "

"형상에서 상기 기판(302)의 양측 표면으로 연장된 연장부(D)로 구성된다. 이때 "

"형상의 양측은 기울기를 가지도록 구성된다.As shown, the support 320 is fitted along the inner wall of the hole H to be fixed to both surfaces of the PCB substrate 302 while being fitted inside the hole H.

"Consisting of shapes, said"

"Consists of an extension D extending in shape to both surfaces of the substrate 302.

"Both sides of the shape are configured to have a slope.

In this case, the surface of the support 320 is coated with a paint having excellent reflection characteristics, or a high reflection film is attached to provide a reflection characteristic.

A metal pattern 318 formed of gold, copper, or the like is attached to the rear surface of the support 320 to increase the heating effect.

Therefore, the flexible backlight unit according to the present invention further includes a flexible optical structure, which can greatly enhance the light diffusion function and improve the mechanical strength of the backlight unit, thereby minimizing the impact on external shocks and thus improving the lifespan. There is a prolongable effect.

Claims (41)

A printed circuit board made of a first polymer material; A plurality of LEDs fixedly arranged on the printed circuit board; An optical structure disposed between the plurality of LEDs on the printed circuit board, the barrier rib being perpendicular to the printed circuit board in a mesh form, and formed of a transparent second polymer material; Located on top of the optical structure, and comprises at least one optical film made of a third polymer material, The optical structure Flexible backlight unit, characterized in that including a light diffusion function therein. delete delete delete delete delete delete delete delete delete delete delete delete delete delete A printed circuit board made of a first polymer material and having a plurality of grooves; A plurality of LEDs configured inside the plurality of grooves; An optical structure disposed between the plurality of LEDs on the printed circuit board, the barrier rib being perpendicular to the printed circuit board in a mesh form, and formed of a transparent second polymer material; Located on top of the optical structure, and comprises at least one optical film made of a third polymer material, The optical structure Flexible backlight unit, characterized in that including a light diffusion function therein. The method according to claim 1 or 16, The first polymer material may be one of an epoxy resin material, an acrylic resin, a polycarbonate, and a polyester, a copolymer thereof, or a glass fiber mixed material. , The second and third polymer material A flexible backlight unit comprising any one of polycarbonate, acrylic and polyester materials. The method according to claim 1 or 16, The plurality of LEDs are flexible backlight unit, characterized in that consisting of red and green and blue and white LEDs. The method of claim 18, Flexible backlight comprising the red and green and blue LEDs as a group, or the white LED as a single group or a cluster consisting of the red and green and blue and green LEDs as a group unit. 20. The method of claim 19, The width of the partition wall forming the optical structure is a flexible backlight unit, characterized in that equal to or less than the distance between the LED or cluster. delete The method according to claim 1 or 16, A reflective layer for reflection is mounted on the front surface of the printed circuit board, The optical structure in the form of a mesh has an opening corresponding to the LED or cluster, the flexible backlight unit, characterized in that located on top of the reflective layer. The method according to claim 1 or 16, The flexible backlight unit further comprises a light guide layer made of the polymer material between the optical structure and the optical film. 24. The method of claim 23, The flexible backlight unit, characterized in that formed on the surface of the light guide layer by selecting an embossed or engraved prism pattern or an embossed or engraved dot pattern. 17. The method of claim 1 or 16, A flexible backlight unit further comprises a micro lens covering the LED. 26. The method of claim 25, The flexible micro-lens unit, characterized in that the spherical or conical or prismatic form. 17. The method of claim 1 or 16, A flexible backlight unit, characterized in that the spherical or conical or prism pattern is engraved or embossed on the surface of the optical film. 24. The method of claim 23, Flexible backlight unit, characterized in that the optical adhesive is further configured between the optical structure and the light guide layer. The method of claim 28 The optical adhesive is a paste or film form, the flexible backlight unit, characterized in that formed with one selected from the acrylic film-based silicone and its copolymer with a small difference in refractive index. 17. The method of claim 1 or 16, Flexible backlight unit, characterized in that it further comprises a phosphor coated on the surface of the LED. 17. The method of claim 16, And a metal pattern having a heat dissipation function on a lower surface of the printed circuit board corresponding to the groove. 32. The method of claim 31, The metal pattern is a flexible backlight unit, characterized in that formed with one selected from metals including gold, copper. A printed circuit board made of a first polymer material and configured with a plurality of holes; A plurality of LEDs fixed through a support in the plurality of holes; An optical structure disposed between the plurality of LEDs on the printed circuit board, the barrier rib being perpendicular to the printed circuit board in a mesh form, and formed of a transparent second polymer material; Located on top of the optical structure, and comprises at least one optical film made of a third polymer material, The optical structure Flexible backlight unit, characterized in that including a light diffusion function therein. 34. The method of claim 33, The first polymer material is one of an epoxy resin material, acrylic, polycarbonate, polyester, or a copolymer thereof, or a glass fiber mixed material. , The second and third polymer material A flexible backlight unit comprising any one of polycarbonate, acrylic and polyester materials. 34. The method of claim 33, The plurality of LEDs are flexible backlight unit, characterized in that consisting of red and green and blue and white LEDs. 36. The method of claim 35, Flexible backlight comprising the red and green and blue LEDs as a group, or the white LED as a single group or a cluster consisting of the red and green and blue and green LEDs as a group unit. 37. The method of claim 35 and 36, wherein The width of the partition wall forming the optical structure is a flexible backlight unit, characterized in that equal to or less than the distance between the LED or cluster. delete 34. The method of claim 33, A reflective layer for reflection is mounted on the front surface of the printed circuit board, The mesh structured optical structure has an opening corresponding to the LED or the cluster and is positioned above the reflective layer. 34. The method of claim 33, The flexible backlight unit further comprises a light guide layer made of the polymer material between the optical structure and the optical film. 34. The method of claim 33, The support is formed along the inner wall of the hole to be fixed to both surfaces of the printed circuit board, including the LED, and to be fixed to both sides of the hole, the flexible backlight unit comprising a support extending to the surface of the substrate .

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