KR101326224B1 - Back light assembly for flexible liquid crystal display device - Google Patents

Abstract

The present invention provides a dielectric substrate comprising a first polymer material and a printed circuit board having wiring formed thereon; A plurality of light emitting diodes fixed to the printed circuit board and electrically connected to each other by the wirings; A micro lens formed on the plurality of light emitting diodes and made of a second polymer material; A light guide material layer formed on the microlens and made of the first polymer material; A backlight assembly for a flexible liquid crystal display device disposed on the light guide layer and including an optical sheet made of the first polymer material.

Flexible, Liquid Crystal Display, Backlight Assembly, Flexibility, Warping

Description

Back light assembly for flexible liquid crystal display device

1 is an exploded perspective view of a general liquid crystal display device

2 is a cross-sectional view of a backlight assembly for a flexible liquid crystal display device having flexible characteristics according to an exemplary embodiment of the present invention.

3 is a cross-sectional view of a backlight assembly for a flexible liquid crystal display device having flexible characteristics according to a modification of the embodiment of the present invention.

4A to 4K are plan views illustrating various arrangements of a printed circuit board and a light emitting diode on the upper side of the flexible LCD display backlight assembly according to the present invention. Figures shown together.

5A to 5D are cross-sectional views illustrating a light guide material layer formed in a flexible liquid crystal display according to an exemplary embodiment of the present invention, and have various patterns with respect to an upper surface thereof.

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

101: backlight assembly (for flexible liquid crystal display)

109: dielectric plate 110: printed circuit board

135: light emitting diode 136: micro lens

138: reflective layer 142: light guide material layer

148: adhesive layer 150: optical sheet

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

In recent years, as the society enters a full-scale information age, a display field for processing and displaying a large amount of information has been rapidly developed, and various various flat panel display devices have been developed and are in the spotlight.

Specific examples of such flat panel display devices include a liquid crystal display device (LCD), a plasma display panel (PDP), a field emission display (FED) And electroluminescence display device (ELD). These flat panel display devices are excellent in performance of thinning, light weight, and low power consumption, and are rapidly replacing existing cathode ray tubes (CRTs).

In particular, a liquid crystal display device is characterized in that it has a large contrast ratio, is suitable for moving picture display, and has low power consumption, and is utilized in various fields such as a notebook computer, a monitor, and a TV. As is well known, liquid crystals have optical anisotropy, in which molecular structures are elongated and directionally oriented, and polarizing properties, in which the direction of molecular arrangement is changed according to their sizes when placed in an electric field.

Accordingly, a liquid crystal display device has a liquid crystal panel in which a pair of transparent insulating substrates, each having a field-generating electrode formed on a surface facing each other with a liquid crystal layer interposed therebetween, Depending on the magnitude of the electric field between the liquid crystal molecules, the alignment direction of the liquid crystal molecules interposed therebetween is artificially adjusted, and various images are displayed through the change of light transmittance.

A configuration of the liquid crystal display module will be described in more detail with reference to FIG. 1, which is an exploded perspective view of a general liquid crystal display module.

As illustrated, the LCD module includes a liquid crystal panel 2 having an array substrate 10 and a color filter substrate 20 bonded to each other with a liquid crystal layer 30 therebetween, and a backlight assembly 40 disposed below the liquid crystal panel 2. In the dual liquid crystal panel 2, the lower array substrate 10 is vertically and horizontally arranged on the first transparent substrate 12 and its upper surface to define a plurality of pixel regions P. A gate wiring 14 and a data wiring 16, and a thin film transistor Tr is provided at the intersection of the two wirings 14 and 16, and has a one-to-one correspondence with the pixel electrode 18 provided in each pixel region P. FIG. Correspondence is connected.

In addition, the upper color filter substrate 20 facing the second transparent substrate 22 and its rear surface may cover the non-display area of the gate line 14, the data line 16, and the thin film transistor Tr. A lattice-like black matrix 25 is formed around each pixel region P, and red, green, and blue color filter layers 26 sequentially and sequentially arranged to correspond to each pixel region P are formed in the lattice. The common electrode 28 is formed on the entire surface of the black matrix 25 and the red, green, and blue color filter layers 26.

Although not clearly shown in the drawings, these two substrates 10 and 20 are each sealed with a sealing agent or the like along the edges to prevent leakage of the liquid crystal layer 30 interposed therebetween. At the boundary between the substrates 10 and 20 and the liquid crystal layer 30, upper and lower alignment layers (not shown) which impart reliability in the molecular alignment direction of the liquid crystal are interposed. The polarizing plate (not shown) is attached to the side.

In addition, a back-light assembly 40 including a light source 46, such as a lamp, is provided on the back of the liquid crystal panel 2 having the above-described configuration, and supplies light. When the on / off signal of the transistor T is sequentially scanned and applied, the image signal of the data line 16 is transferred to the pixel electrode 18 of the selected pixel region P, and a vertical electric field therebetween. By this, liquid crystal molecules are driven therebetween, and various images can be displayed by the change of the transmittance of light.

As described above, the liquid crystal display device 1 is a light-receiving element that does not have its own light emitting element, and thus requires a separate light source. For this purpose, a backlight assembly 40 is formed on the back of the liquid crystal panel 2. Is providing light.

On the other hand, in the liquid crystal display device having such a configuration, glass substrates have traditionally been used for the first and second insulating substrates 12 and 22, which are the matrixes of the array substrate 10 and the color filter substrate 20. For example, as small portable terminals such as laptops and PDAs (personal digital assistants) are widely used, liquid crystal panels using plastic substrates that are lighter, lighter, and more flexible than glass and have a low risk of breakage have been introduced. There is a bar.

Although the liquid crystal panel 2 having such a flexible characteristic is commercialized and mass-produced, the backlight assembly 40 still does not have a product having a flexible characteristic, and thus the liquid crystal display apparatus 1 having a substantially flexible characteristic has not been commercialized. .

Accordingly, an object of the present invention is to provide a backlight assembly having flexible characteristics.

In order to achieve the above object, there is provided a backlight assembly for a flexible liquid crystal display device, comprising: a printed circuit board having a dielectric plate made of a first polymer material and a wiring formed thereon; A plurality of light emitting diodes fixed to the printed circuit board and electrically connected to each other by the wirings; A micro lens formed on the plurality of light emitting diodes and made of a second polymer material; A light guide material layer formed on the microlens and made of the first polymer material; Located on the light guide layer and includes an optical sheet made of the first polymer material.

In this case, the plurality of light emitting diodes, each of which is characterized in that formed at a predetermined interval apart.

In addition, the plurality of light emitting diodes may be formed in a group and spaced apart from each other by a predetermined interval, wherein the microlenses are formed corresponding to each of the groups. In addition, the group consists of three colors of red, green, and blue light emitting diodes, or four colors of red, green, blue, and white light emitting diodes, or three colors of red, green, and blue, and one of these three colors. In addition, the light emitting diodes are characterized by being composed of four light emitting diodes, wherein the three color light emitting diodes are arranged in a triangular shape or a straight shape, and the light emitting diodes consisting of four color light emitting diodes or three colors of four are arranged in a rectangular shape. It is characteristic.

In addition, the micro-lens is characterized in that the shape of the hemispherical or square pyramid, the micro-lens is characterized in that it is formed in a state of being spaced apart or in contact with the neighboring microlens.

The light emitting diode is characterized by consisting of a white light emitting diode for emitting white light.

In addition, the lower surface of the light guide material layer is formed to capture the micro lens, the upper surface is characterized in that the hemisphere, the cone, the prism acid having a triangular cross-section is embossed or engraved pattern.

  In addition, the light guide material layer is characterized in that it further comprises a plurality of beads (bead) in the form of diffusing, dispersing light therein, the first polymer material is one of acrylic, polycarbonate, polyester or these It is a characteristic that it is a copolymer of.

In addition, the optical sheet and the light guide material layer further comprises an adhesive layer made of a third polymer material, wherein the third polymer material is characterized in that the silicone or acrylic or a copolymer thereof.

In addition, the second polymer material is characterized in that the epoxy, silicone or acrylic.

In addition, the dielectric plate may include glass fibers in addition to the first polymer material, and the first polymer material constituting the dielectric plate may further include an epoxy resin.

In addition, the optical sheet is characterized in that at least one of the upper surface or the lower surface has a hemisphere, a cone, a pattern in which the prism acid having a triangular shape is embossed or engraved.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the drawings.

2 is a cross-sectional view of a flexible liquid crystal display backlight assembly having a flexible characteristic according to an embodiment of the present invention, Figure 3 is a cross-sectional view of a flexible liquid crystal display backlight assembly having a flexible characteristic according to a modification of the present invention to be.

As illustrated, the flexible backlight assembly 101 for flexible liquid crystal display according to an embodiment of the present invention is a resin material such as epoxy or acrylic, polycarbonate, polyester and copolymers thereof at the bottom thereof. The printed circuit board 110 is formed by forming a copper thin film on the surface of the flexible dielectric plate 109 formed of a material in which a polymer material and glass fiber are mixed and etching the same. The light emitting diode 135 is connected to the wirings (not shown) on the upper surface of the printed circuit board 110 and a plurality of light emitting diodes 135 are fixedly arranged in a matrix form.

In addition, the most characteristic part of the present invention covers the plurality of light emitting diodes 135 and is made of a transparent polymer material such as epoxy, silicon, acrylic, etc., and has a flexible micro lens 136. At this time, the cross-sectional structure of the micro lens 136 is a semi-circular or triangular shape (see Fig. 3, 137) is characterized in that the planar hemispherical or square pyramid shape.

In addition, the microlens 136 of this type may be configured for each light emitting diode 135, or a microlens may be configured for each group by using three light emitting diodes or four color light emitting diodes as one group.

The reason why the microlens 136 is formed on the light emitting diode 135 is to diffuse the light emitted from the light emitting diode 135 through the microlens 136 having a specific pattern. When the light source is composed of a plurality of light emitting diodes 135, the brightness of light is decreased in the spaced area between the light emitting diodes 135, and the luminance difference is shown as a stain on the screen of the liquid crystal display device. In order to minimize the difference in brightness by using the light guide material layer 142 and the optical sheet 150, however, a stain or the like occurs due to a minute brightness difference, and this problem is solved by a microlens on the light emitting diode 135. In order to improve luminance deterioration in the spaced area between the light emitting diodes 135, the light emitting diodes 136 are provided to diffuse the light.

4A to 4K are plan views illustrating various arrangements of a printed circuit board and a light emitting diode on the upper side of the flexible LCD display backlight assembly according to the present invention. Figure is shown together.

The arrangement of the plurality of light emitting diodes 135 fixed on the printed circuit board will be described.

4A to 4I, first, as shown in FIGS. 4A to 4E, red, green, and blue (R, G, B) light emitting diodes which form white light of high purity by simultaneously emitting light as the first arrangement example 135a, 135b, and 135c form one group gr1, and these three color light emitting diodes 135a, 135b, and 135c are used as a group gr1, and a plurality of groups gr1 are spaced at regular intervals on the front and rear. And can be placed.

At this time, the arrangement of each of the light emitting diodes 135a, 135b, and 135c in the group gr1 of the three-color light emitting diodes 135a, 135b, and 135c may be a triangle (see FIGS. 4A to 4C) or a straight shape (FIGS. 4D and 4E). ) Form.

In this case, for the light emitting diodes 135a, 135b, and 135c having such an arrangement, the light emitting diodes 135a, 135b, and 135c are generally hemispherical to one light emitting diode (135a, 135b, and 135c) irrespective of each group gr1 (Figs. 4A and 4D). One of these groups (gr1) for each group (gr1) in which a microlens (136a) in the form of a square pyramid (Figs. 4b, 4e) is formed or the three-color light emitting diodes (135a, 135b, 135c) are bundled. One hemispherical microlens 136b is formed for one. In this case, each of the micro lenses 136a or 136b formed individually or by group gr1 may be formed to be spaced apart from the neighboring micro lenses 136a or 136b by a predetermined distance (see FIGS. 4B, 4D, and 4E), or spaced apart from each other. It may be formed without gaps (see FIG. 4A).

On the other hand, as a second example of the arrangement of the light emitting diodes 135, red, green, blue and white (R, G, B, W) light emitting diodes (135a, 135b, 135c) as shown in Figs. , 135d may form one group gr2, and the plurality of groups gr2 may be formed to be spaced a predetermined distance on the front surface by using the four-color light emitting diodes 135a, 135b, 135c, and 135d as groups gr2. At this time, the arrangement of each of the light emitting diodes 135a, 135b, 135c, and 135d in the group gr2 of the four color light emitting diodes 135a, 135b, 135c, and 135d becomes a quadrangular shape. In this case, although not shown in the drawing, the four-color LED is composed of red, green, blue, and white (R, G, B, W) in addition to the three colors of red, green, blue, and any one of them. For example, it may be composed of four light emitting diodes consisting of three colors of red, green, blue and red, or three colors of red, green, blue and green.

In the case of the four-color light emitting diodes 135a, 135b, 135c, and 135d as one group gr2, the light emitting diodes 135a, 135b, 135c, and 135d cover the light emitting diodes 135a, 135b, 135c, and 135d regardless of the group gr2. Each group (gr2) composed of microlenses 135a and 136b in the form of hemispherical shape (see FIGS. 4F and 4H) or quadrangular pyramid (see FIG. 4G) or grouping the four color light emitting diodes 135a, 135b, 135c and 135d. ), Each of these groups gr2 is characterized by the formation of one hemispherical microlens 136a (see FIG. 4I). At this time, each of the micro lenses 135a and 136b may be formed to be spaced apart from the neighboring micro lenses 136a by a predetermined distance (see FIG. 4G) or may be formed without a space (see FIGS. 4F and 4H).

 In addition, as a third arrangement example, as shown in FIGS. 4J and 4K, only the white (w) light emitting diode 135d that emits white light by itself may be spaced apart at regular intervals in a matrix form on the front surface. It may be.

In the light emitting diode 135d having such an arrangement, microlenses 136a having a hemispherical shape (see FIG. 4J) or a quadrangular pyramid shape (see FIG. 4K) are formed for each of the light emitting diodes 135d.

Referring back to FIG. 2, an insulating material having high reflectance is coated on the surface of the printed circuit board 110 exposed to the outside of the plurality of light emitting diodes 135, or the reflective sheet having the plurality of holes is a transparent adhesive material. The reflective layer 138 is formed by being bonded together. In this case, the reflective sheet (not shown) is preferably attached so that the plurality of holes correspond to each of the light emitting diodes 135 so that the light emitting diode 135 is not covered by the reflective sheet (not shown).

In the backlight assembly 101 for a flexible liquid crystal display device according to an exemplary embodiment of the present invention, the light emitting diode 135 is directly below the lowermost front surface, and the reflective sheet is the same as the backlight assembly using a general lamp. If the printed circuit board 110 is provided under the printed circuit board 110, the printed circuit board is exposed to the outside of the light emitting diode in order to increase reflection efficiency since the light emitting diode 135 has a structure that is covered by a wiring (not shown). The reflective layer 138 is formed by attaching a coating or reflective sheet to the surface of the substrate 110.

Next, as described above, the light emitting diode 135 and the reflective layer 138 exposed to the outside of the light emitting diode 135 are excellent in ductility, which is arranged on the printed circuit board 110 having flexible characteristics. The light guide material layer 142 made of a polymer material having excellent light transmissivity and excellent heat resistance, for example, one of acrylic, polycarbonate, and polyester, or a copolymer of the material is formed. The light guide material layer 142 made of such a material is very flexible, and even though both ends are held with respect to the upper surface thereof and the appropriate force is applied to these ends to adhere to each other, the bending property is excellent, as if a cylinder is formed. It is possible to achieve a shape, and the restoring force is also very good so that the applied force is removed and has the characteristic of being restored to its original form, that is, a flat state.

In this case, the light guide material layer 142 includes a recess in the form of the microlens 136 formed on the lower surface of the light guide material layer 142 to cover the light emitting diode 135 through the recess. The upper surface may be formed to have a flat surface, as shown in the figure, or a cross-sectional view showing a light guide material layer of the flexible liquid crystal display device according to the present invention. As shown in Figures 5a to 5d showing that having a variety of patterns for, can be configured to have a predetermined pattern form in embossed or intaglio, or to improve the diffusion or condensing ability of light therein It may also include multiple beads in the form.

 As an example, as shown in FIGS. 5A and 5B, the upper surface of the light guide material layer 142 has a plurality of valleys and acids, that is, a pattern having a plurality of prismatic acids whose cross sections are triangular or semicircular. 144 may be embossed, or as shown in FIGS. 5C and 5D, a pattern 145 having a plurality of prismatic peaks whose cross sections are triangular or semicircular may be formed in the form of intaglio. .

In addition, in a state in which the specific patterns 144 and 145 are formed in an embossed or intaglio form on the top surface, a plurality of beads 147 having a spherical shape may be formed therein. This is to allow the light incident upon the bottom to diffuse internally through the plurality of beads 147 so that the light propagation path is appropriately changed so that the light exits to the upper surface efficiently.

The reason for achieving such a structure is to more efficiently and evenly emit the light emitted from the lower light emitting diode 135 without spots due to luminance difference on the front surface.

Next, a plurality of optical sheets 150 are provided on the light guide material layer 142 having a specific pattern 144 and 145 structure with respect to the upper surface thereof as described above. By doing so, a flexible backlight assembly 101 for a liquid crystal display device having flexible characteristics according to an exemplary embodiment of the present invention is completed.

In this case, the plurality of optical sheets 150 also have the same material constituting the light guide material layer 142, that is, the material of one of acrylic, polycarbonate, polyester or the like in order to have the most flexible characteristics of the present invention It is characterized by consisting of a copolymer of the substance.

In addition, the plurality of optical sheets 150 may have a hemisphere or cone or a similar shape to the top surface of the light guide material layer 142 with respect to at least one of the top surface and the bottom surface in order to improve light condensing characteristics or light diffusing functions. The prism acid-shaped pattern having a triangular or semi-circular cross section is embossed or engraved.

At this time, between the light guide material layer 142 and the optical sheet 150 by coating an organic adhesive material having excellent optical properties, that is, light transmittance, such as acrylic or silicon and a transparent adhesive material made of a copolymer of these materials, an adhesive layer ( 148 may be further configured. In this case, the adhesive layer 148 may be coated with a paste type adhesive material, which may be coated on the upper surface of the light guide material layer 142, or may be a gel type film type. Can be formed.

The reason why the light guide material layer 142 and the optical sheet 150 are formed by bonding the adhesive layer 148 is that the backlight assembly 101 according to the present invention has the flexibility to have a bending characteristic. When the warpage occurs, the positions of the light guide material layer 142 and the optical sheet 150 may be changed, and thus, functions such as light diffusion and condensation of the optical sheet 150 may be degraded. This is to prevent the problem.

In the case of the backlight assembly 101 according to the exemplary embodiment of the present invention, the printed circuit board 110 may have a flexible characteristic, and the light guide material layer 142 and the upper surface thereof may be arranged in parallel. As a result, the bending of the light guide material layer 142 may be freely performed in any of up, down, left, and right directions with respect to the top surface of the light guide material layer 142.

In addition, the backlight assembly according to the present invention, which is manufactured to have the above-described configuration using a polymer material having excellent flexibility, is broken even if the end of the backlight assembly is brought into contact with each other, that is, having a bending angle of 180 degrees or more. It can be used without being damaged or damaged.

The backlight assembly having a flexible characteristic according to the present invention has an effect of enabling a flexible liquid crystal display apparatus having a flexible characteristic that can be bent by configuring a liquid crystal panel having a flexible characteristic.

In addition, by forming a microlens having a specific pattern shape on the light emitting diode, the light emitted from the light emitting diode is diffused to be incident on the light guide material layer, thereby preventing a decrease in luminance in a spaced area of the light emitting diode.

Claims (19)

A dielectric board made of a flexible first polymer material and a printed circuit board formed thereon; A plurality of light emitting diodes fixed on the printed circuit board along a length direction and electrically connected to each other by the wirings; A micro lens formed on the plurality of light emitting diodes and made of a second polymer material; A light guide material layer formed on an upper surface of the micro lens to capture the micro lens and made of the first polymer material; An optical sheet attached to the light guide material layer and formed of the first polymer material Backlight assembly for a flexible liquid crystal display comprising a. The method of claim 1, The plurality of light emitting diodes, each of which is formed at a predetermined interval apart from the backlight assembly for a flexible liquid crystal display device. The method of claim 1, The plurality of light emitting diodes, a plurality of light emitting diodes, characterized in that formed in one group spaced apart from the predetermined interval between the groups. The method of claim 3, wherein And the microlenses are formed corresponding to each of the groups. Claim 5 was abandoned upon payment of a set-up fee. The method of claim 3, wherein The group consists of three color LEDs of red, green, and blue, or further includes four color LEDs of red, green, blue, and white, or three colors of red, green, and blue, and one of these three colors. The backlight assembly for a flexible liquid crystal display device characterized in that consisting of four light emitting diodes. Claim 6 has been abandoned due to the setting registration fee. 6. The method of claim 5, The three-color light emitting diodes are arranged in a triangular shape or a straight shape, the backlight assembly for a flexible liquid crystal display device. Claim 7 has been abandoned due to the setting registration fee. 6. The method of claim 5, And the four-color light emitting diodes or the four-color light emitting diodes are arranged in a quadrangular shape. The method of claim 1, The microlens has a hemispherical shape or a square pyramid shape, the backlight assembly for a flexible liquid crystal display device. The method of claim 1, And the micro lenses are formed to be spaced apart or in contact with neighboring micro lenses. Claim 10 has been abandoned due to the setting registration fee. The method of claim 2, The light emitting diode is a backlight assembly for a flexible liquid crystal display device, characterized in that consisting of a white light emitting diode for emitting white light. The method of claim 1, The upper surface of the light guide material layer has a hemisphere, a cone, a prism acid having a triangular cross-section thereof has an embossed or engraved pattern of the backlight assembly for a flexible liquid crystal display device. The method according to claim 1 or 11, wherein And the light guide material layer further comprises a plurality of spherical beads for diffusing and dispersing light therein. The method of claim 1, The first polymer material is one of acrylic, polycarbonate and polyester or a copolymer thereof. The backlight assembly for a flexible liquid crystal display device. The method of claim 1, The backlight assembly for a flexible liquid crystal display device further comprising an adhesive layer made of a third polymer material between the optical sheet and the light guide material layer. 15. The method of claim 14, The third polymer material is silicone or acrylic or a copolymer thereof. The backlight assembly for a flexible liquid crystal display device. The method of claim 1, The second polymer material is an epoxy, silicon, or acrylic backlight assembly for a flexible liquid crystal display device. The method of claim 1, The dielectric plate includes a glass fiber in addition to the first polymer material. The method according to claim 1 or 17, The first polymer material constituting the dielectric plate further comprises an epoxy resin. The method of claim 1, And at least one of the top and bottom surfaces of the optical sheet has a hemisphere, a cone, and a pattern in which a prism acid having a triangular cross section is embossed or engraved.

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