KR20160001371A - Complex optical film and, light source assembly including the same - Google Patents

Abstract

Provided are a composite optical sheet, a backlight assembly including the same, and a liquid crystal display device. The composite optical sheet comprises a light guide element, a second substrate, and a first bonding layer. The light guide element comprises: a first substrate having a light guide function; a micro prism which is formed on the top surface of the first substrate, and includes a plurality of prism units; and a scattering pattern layer formed on the bottom surface of the first substrate. The second substrate is placed on the upper part of the first substrate. The first bonding layer is formed on the bottom surface of the second substrate, and is coupled to at least a portion of the micro prism, touching or penetrating the first bonding layer. A gap between neighboring unit prisms is larger than the width of the unit prism.

Description

[0001] The present invention relates to a composite optical sheet and a backlight assembly including the composite optical sheet,

The present invention relates to a composite optical sheet, and more particularly, to a composite optical sheet to be applied to a display and a backlight assembly including the same.

A liquid crystal display (LCD) is a device for displaying an image by injecting liquid crystal between two glass plates and applying power to the upper and lower glass plate electrodes to change the arrangement of liquid crystal molecules in each pixel. Unlike a cathode ray tube (CRT), a plasma display panel (PDP) or the like, a display using a liquid crystal display device is not usable in a place where there is no light because the display itself is non-luminous. In order to compensate for these drawbacks, a backlight assembly that is uniformly irradiated on the information display surface is mounted for the purpose of enabling use in a dark place.

BACKGROUND ART [0002] Backlight assemblies used in liquid crystal display devices are classified into two types. The first type is an edge type backlight assembly that provides light at the side of the liquid crystal display device. The second type is a direct type backlight assembly that provides light directly at the rear side of the liquid crystal display device. In the case of an edge type backlight assembly, a light guide plate is provided so that light emitted from a light source is irradiated upward, and at least one optical sheet is provided above the light guide plate to control optical characteristics of light passing through the light guide plate.

However, the light guide plate is generally thick and bulky, which hinders lightening and thinning of the backlight assembly. In addition, misalignment with the optical sheet or development of the optical sheet on the light guide plate may occur, in which case the reliability of the light control is reduced.

In addition, when the number of optical sheets is increased, not only the thickness and the cost are increased, but also light can be reflected or absorbed while passing through the optical sheet, thereby reducing the total luminance. In addition, the assembling process becomes complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a composite optical sheet in which a light guiding function and a plurality of optical modulation characteristics are effectively realized.

Another object of the present invention is to provide a backlight assembly in which a light guiding function and a plurality of light modulation characteristics are effectively implemented.

It is another object of the present invention to provide a liquid crystal display device in which a light guiding function and a plurality of light modulation characteristics are effectively implemented to improve brightness and image quality.

The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a composite optical sheet comprising a first substrate having a light-guiding function, a micro prisms formed on an upper surface of the first substrate, and a scattering pattern layer formed on a lower surface of the first substrate, A second base material disposed on the first base material, and a first bonding layer formed on a bottom surface of the second base material, wherein at least a part of the microprism is in contact with or penetrates into the first bonding layer.

According to another aspect of the present invention, there is provided a backlight assembly including the composite optical sheet as described above.

According to another aspect of the present invention, there is provided a liquid crystal display device including the composite optical sheet as described above.

The details of other embodiments are included in the detailed description and drawings.

The embodiments of the present invention have at least the following effects.

That is, according to the composite optical sheet and the backlight assembly including the composite optical sheet according to embodiments of the present invention, as one integrated sheet, it is possible to precisely implement not only the light guiding function but also a plurality of optical modulations. Accordingly, the thickness and weight of the backlight assembly can be reduced. In addition, the luminance and image quality of the liquid crystal display device employing this can be improved.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the specification.

1 is a cross-sectional view of a composite optical sheet according to an embodiment of the present invention.
2 is a plan view of the light guiding member.
3 is a bottom view of the light guiding member.
4 is a Bézier curve relating to the scattering pattern density of the light guiding member.
5 is a cross-sectional view of a backlight assembly according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

It is to be understood that elements or layers are referred to as being "on " other elements or layers, including both intervening layers or other elements directly on or in between. On the other hand, a device being referred to as "directly on" refers to not intervening another device or layer in the middle. Like reference numerals refer to like elements throughout the specification. "And / or" include each and any combination of one or more of the mentioned items.

Although the first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical scope of the present invention.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms " comprises "and / or" comprising "used in the specification do not exclude the presence or addition of one or more other elements in addition to the stated element.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" And can be used to easily describe a correlation between an element and other elements. Spatially relative terms should be understood in terms of the directions shown in the drawings, including the different directions of components at the time of use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element . Thus, the exemplary term "below" can include both downward and upward directions. The components can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

As used herein, the term "film" can be used in the sense of "to sheet"

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a cross-sectional view of a composite optical sheet according to an embodiment of the present invention.

1, the composite optical sheet 11 includes a light guide member 150, at least one optical pattern disposed on the light guide member 150, and integrated with the light guide member 150 to be integrated.

2 is a plan view of the light guiding member. 3 is a bottom view of the light guiding member. 1 to 3, the light guiding member 150 includes a first base 101, a micro prism 110 formed on the upper surface of the first base 101, and scattering formed on the lower surface of the first base 101 And a pattern layer 120.

The first base material 101 may be formed of a transparent plastic. For example, the first substrate 101 may be formed of a material selected from the group consisting of a polycarbonate series, a poly sulfone series, a polyacrylate series, a polystyrene series, a poly vinyl chloride , Polyvinyl alcohol series, poly norbornene series, and polyester ester series materials. [0034] The term " polyvinyl alcohol " In some exemplary embodiments, the first substrate 101 may be made of PET (Polyethylene phthalate). The first substrate 101 may be made of a somewhat flexible material. The first base material 101 may be provided in a stretched type, but may be provided in a non-stretched type.

The first base material 101 may perform a light-guiding function. That is, when employed in the backlight assembly, the light source may be disposed adjacent to one side of the first substrate 101. The light emitted from the light source enters the interior of the first base 101 through one side (light incoming surface) of the first base 101 and can be transmitted to the opposite side (the opposite light side) through total internal reflection. The first base material 101 that performs the light guiding function may be thicker than the second base material 102 described later, but the present invention is not limited thereto. The thickness of the first base material 101 is preferably equal to or greater than the thickness of the adjacent light sources. The thickness of the first base material 101 may be about 250 탆 to 1000 탆.

The first base material 101 may have a uniform thickness of one side surface and the other side surface, but may be formed in a so-called wedge-type type in which the thickness of the other side surface is smaller than the thickness of one side surface.

A micro prism 110 is formed on an upper surface of the first base material 101. The micro prisms 110 may be made of a thermosetting resin or an ultraviolet ray curable resin. Examples of the thermosetting resin include an acrylic resin, a urethane resin, and a polyester resin. Examples of the ultraviolet ray curable resin include an epoxy acrylate resin, a urethane acrylate resin, and a silicone acrylate resin. The micro prisms 110 may be made of a material different from that of the first base material 101, but may be made of the same material, or may be integrally formed.

The micro prisms 110 may include a plurality of unit prisms formed on the relaxation part and the relaxation part. The relaxation unit physically connects the mutually spaced unit prisms. The mitigating part and the unit prism are made of the same material and can be integrally formed without an interface therebetween. The relaxation part may be omitted. In this case, the unit prisms may be formed directly on the upper surface of the first base 101.

The tip of the unit prism may contact or at least partly penetrate the first bonding layer 211 formed on the lower surface of the second base 102. An exposed relieved portion between the unit prisms or an upper surface of the first base material 101 (in the absence of a relaxed portion) may be spaced apart from the first coupling layer 211, and a low refractive index region such as an air layer may be interposed .

The unit prisms all extend in a constant direction. The neighboring unit prisms are spaced from each other, and the spacing distance is larger than the width of the unit prism.

The unit prism may have a vertex angle of about 90 degrees, and the cut surface may be a vertically isosceles triangle. In this case, the width of the unit prism is twice the unit prism height.

The larger the size of the unit prism and the smaller the pitch (pt), the higher the brightness. However, if the prism size is too large, the pattern line can be viewed when viewed from above. On the other hand, if the size of the unit prism is too small, it is difficult to sufficiently bond with the first coupling layer 211, or a low refractive index region may be formed between the first coupling layer 211 and the relaxed portion or the upper surface of the first base 101 It may not be intervening. If the low refractive index region is not interposed in the region, the luminance improving effect may not be exerted.

From this point of view, the unit prism is smaller than the prism applied as the optical pattern. For example, the height of the unit prism may be 3 to 10 mu m or 4 to 7 mu m.

If the pitch pt of the unit prisms is too large, the brightness enhancement effect is small and the bonding force between the first bonding layers 211 can be weakened. If the unit prism pitch pt is too small, it is difficult to adjust the uniformity of light incident from the side. That is, light incident from the side can not be sufficiently transmitted to the light-shielding portion through total reflection, and light can be emitted from the light-shielding portion relatively to the upper side. In this point of view, the pitch pt of the unit prisms may be substantially equal to or smaller than the prism pitch of the optical pattern disposed on the upper portion of the light guide member 150. For example, the unit prism pitch pt of the micro prisms 110 may be 10 to 60 占 퐉 or 20 to 50 占 퐉.

A scattering pattern layer 120 is formed on the lower surface of the first base material 101. The scattering pattern layer 120 may be made of a thermosetting resin or an ultraviolet ray curing resin similarly to the constituent material of the microprism 110. The scattering pattern layer 120 has a relief pattern 121 on the surface. The scattering pattern 121 is arranged in an island type and has a finer arrangement from the light-incoming portion to the light-shielding portion. The shape of the scattering pattern 121 can be variously modified such as a tote pattern, a prism pattern, and a square. The density of the scattering pattern 121 and the number of patterns depending on the position can be determined by a Bezier curve.

4 is a Bézier curve relating to the scattering pattern density of the light guiding member.

Referring to FIG. 4, the X axis represents a relative displacement with respect to the center of the light guide member 150, and the Y axis represents the relative number of scatter patterns at the coordinates. A Bezier curve defines a point B0 at a position of a light-incoming portion (X coordinate: -90) pattern number 0 and an end point B2 at a position of a light number portion (X coordinate: 90) The control point B1 can be located in the lower right quadrant of the graph plane. For example, the X-axis coordinate of the control point B1 may be between 0 and 75, and the Y-axis coordinate may be selected between 20 and 50. The density of the scattering pattern determined within the above range is advantageous for uniformly scattering the light totally reflected in the first base 101 of the light guide member 150 upward.

Referring back to FIG. 1, at least one optical pattern is disposed on the light guiding member 150. The optical pattern may be provided on a substrate. In the exemplary embodiment shown in Fig. 1, an example in which three optical patterns are formed on three substrates is shown.

That is, the second base material 102, the third base material 103 and the fourth base material 104 are sequentially laminated on the upper surface of the light guide member 150, and the first optical pattern 210 A second optical pattern 220 is disposed on the upper surface of the third base material 103 and a third optical pattern 230 is disposed on the upper surface of the fourth base material 104. A first bonding layer 211 is formed on the lower surface of the second base material 102, and the first optical pattern 210 is at least partially in contact with or penetrates and is bonded. A second bonding layer 212 is formed on the lower surface of the third base material 103, and the second optical pattern 220 is at least partly in contact with or penetrates. A low refractive index region such as an air layer may be interposed between the second bonding layer 212 and the first optical pattern 210 and between the third bonding layer 213 and the second optical pattern 220. [

The second base material 102, the third base material 103, and the fourth base material 104 may each be formed of a transparent plastic material, and specifically may be made of a material exemplified by the constituent material of the first base material 101 have. In the exemplary embodiment, the second base material 102, the third base material 103, and the fourth base material 104 are all made of the same material but made of a different material from the first base material 101 responsible for the light guiding function . The thickness of the base material may also be smaller than the thickness of the first base material 101 and may be, for example, 50 to 150 占 퐉, Lt; / RTI >

In an exemplary embodiment, the first optical pattern 210 is an amorphous diffusion pattern, the second optical pattern 220 is a prism pattern, and the third optical pattern 230 is a micro lens pattern.

Specifically, the first optical pattern 210 has an optical acid function and a light shielding function for preventing a dark portion and a dark portion from being visible. The first optical pattern 210 has an irregular non-planar surface and may include recesses and protrusions. The convex portion of the first optical pattern 210 abuts on the second bonding layer 212 or penetrates into the second bonding layer 212 to bond. The concave portion of the first optical pattern 210 is spaced apart from the second bonding layer 212, and a low refractive index region is interposed.

The height difference between the convex portion and the concave portion of the first optical pattern 210 for diluting the curved portion and the curved portion to realize effective light shielding can be adjusted within a range of about 5 μm to 100 μm. In some embodiments, the height difference between the convex and concave portions of the first optical pattern 210 may be between about 10 microns and 50 microns. The depth of penetration of the convex portion of the first optical pattern 210 into the second bonding layer 212 may be about 0.5 to 10 mu m. In some embodiments, the penetration depth may be about 1 to 7 mu m. In some other embodiments, the penetration depth may be about 2 to 5 탆.

The second optical pattern 220 serves as a prism pattern to enhance the upward brightness by condensing the light. The second optical pattern 220 includes a plurality of prisms. Each prism includes a prism surface inclined to both sides with respect to the prism mountain portion at the upper end. The prism may have substantially the same shape as the micro prisms 110 of the light guiding member 150. However, its size may be larger. For example, the overall width of the prism may be about 20 to 100 micrometers and the height may be about 10 to 60 micrometers. The prism extension direction of the second optical pattern 220 may be substantially the same as the extending direction of the microprism 110 of the light guide member 150 or may intersect at an intersection angle of 90 degrees.

The third optical pattern 230 is a microlens pattern, and performs a function of condensing and diffusing. A case where a microlens layer is applied is exemplified. The third optical pattern 230 may include a plurality of microlenses. Each microlens may have the shape of a structure that is understood to be a sphere or an ellipsoid cut to a specific plane. The bottom surface of the microlens may be a circle, an ellipse, or a cube. The average size of the microlenses can be selected in the range of 20 占 퐉 to 100 占 퐉. The size of each microlens may be uniform, but various microlenses having different values within the above range may be arranged.

Each microlens may be formed on the front surface of the third substrate 103. The neighboring microlenses may be adjacent to each other, but may be wholly or partially spaced. In a regular-grained lens whose bottom surface of the microlens is hexagonal, the microlenses may extend in three directions substantially intersecting each other, and the crossing angle may be 60 °.

The first optical pattern 210, the second optical pattern 220, and the third optical pattern 230 may all be made of a thermosetting resin or an ultraviolet curable resin. Examples of the thermosetting resin include an acrylic resin, a urethane resin, and a polyester resin. Examples of the ultraviolet ray curable resin include an epoxy acrylate resin, a urethane acrylate resin, and a silicone acrylate resin.

The first bonding layer 211, the second bonding layer 212, and the third bonding layer 213 may be formed of a bonding material layer, for example, an adhesive layer, an adhesive layer, or a resin layer. Examples of the material constituting the bonding layer 211-213 include a silicone polymer, a urethane polymer, a silicone-urethane hybrid polymer SU polymer, an acrylic polymer, an isocyanate polymer, a polyvinyl alcohol polymer, a gelatin polymer, a vinyl polymer, a latex polymer, , A water-based polyester-based polymer, and the like.

The order of the first optical pattern 210, the second optical pattern 220, and the third optical pattern 230 may be changed or a part thereof may be omitted. Alternatively, other patterns such as a lenticular pattern, . At least one of the second base material 102, the third base material 103, and the fourth base material 104 may be omitted. At least two of the first to third optical patterns may be formed of the same kind of patterns.

As described above, according to the composite optical sheet 11 according to the present embodiment, it is possible to display not only an improved light-guiding function but also various light-modulating functions with only one composite optical sheet integrated. Therefore, problems such as misalignment between the light guide plate and the optical sheet do not occur, so that precise light control is possible, and it is also advantageous in luminance improvement. Further, since the light guide plate can be substituted for the backlight assembly, it can contribute to the thinning of the backlight assembly.

Hereinafter, the composite optical sheet 11 as described above may be employed in a backlight assembly, a liquid crystal display device including the same, and the like to improve light efficiency. Hereinafter, the composite optical sheet 11 according to the embodiment of FIG. 1 is applied to a liquid crystal display including an edge-type backlight assembly.

5 is a cross-sectional view of a backlight assembly according to an embodiment of the present invention.

5, the backlight assembly 700 according to the present embodiment includes a light source 710, a composite optical sheet 11 that guides light emitted from the light source 710 upward and performs an optical modulation function, A reflection sheet 720 disposed below the optical sheet 11 and a storage container 740 for housing the light source 710, the light guide plate 730, the reflection sheet 720, the composite optical sheet 11, do. As the composite optical sheet 11, a composite optical sheet according to various embodiments of the present invention as well as the composite optical sheet 11 of FIG. 1 described above can be applied.

The light source 710 is disposed on both sides of the composite optical sheet 11. The light source 710 may be a light emitting diode (LED), a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), or an external electro fluorescent lamp (EEFL). In another embodiment, the light source 710 may be disposed only on one side of the composite optical sheet 11.

1) of the composite optical sheet 11 moves the light emitted from the light source 710 through the total internal reflection and diffuses the light through the scattering pattern layer (120 in FIG. 1) formed on the lower surface And emits it upward. A reflective sheet 720 is disposed under the composite optical sheet 11 to reflect light emitted downward from the light guide plate 730 upward.

The light emitted upward can be optically modulated through the optical pattern of the composite optical sheet 11.

As described above, according to the backlight assembly 700 according to the present embodiment, as one integrated sheet, not only the light guiding function but also a plurality of optical modulations are precisely implemented, so that the thickness and weight of the backlight assembly can be reduced have. In addition, the luminance and image quality of the liquid crystal display device employing this can be improved.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

11: Composite optical sheet
101: first substrate
102: second substrate
103:
104: fourth description
110: smile prism
120: scattering pattern layer
210: first optical pattern
220: second optical pattern
230: Third optical pattern

Claims (12)

A light guide member including a first base material having a light guiding function, a micro prism formed on an upper surface of the first base material and including a plurality of unit prisms, and a scattering pattern layer formed on a lower surface of the first base material;
A second substrate disposed on the first substrate; And
And a first bonding layer formed on a bottom surface of the second base material and contacting at least a part of the microprism and penetrating the first bonding layer,
Wherein the interval between adjacent unit prisms is larger than the width of the unit prism. The method according to claim 1,
Wherein a height of the unit prism is 3 to 10 mu m and a pitch of the unit prism is 10 to 60 mu m. The method according to claim 1,
Further comprising a prism pattern disposed on the second substrate,
Wherein the extending direction of the prism pattern and the unit prism extension direction of the micro prisms are the same or perpendicular to each other. The method according to claim 1,
Wherein the scattering pattern layer includes a plurality of positive or negative scattering patterns on a surface thereof. 5. The method of claim 4,
The scattering pattern is arranged in an island type,
Wherein the array density of the scattering pattern increases from one light-incident portion of the first substrate to the other, the second light-shield portion of the first substrate. 6. The method of claim 5,
Wherein the density of the scattering pattern is determined using a Bezier curve for each position from the light-incident portion to the light-incident portion. The method according to claim 1,
A first optical pattern formed on the upper surface of the second substrate;
A third substrate disposed on the first optical pattern;
A second coupling layer formed on the third substrate and having the first optical pattern at least partially bonded thereto; And
And a second optical pattern formed on an upper surface of the third substrate. 8. The method of claim 7,
Wherein the first optical pattern is an amorphous diffusion pattern layer,
And the second optical pattern is a prism layer. 8. The method of claim 7,
A fourth substrate disposed on the second optical pattern;
A third bonding layer formed on the fourth surface of the substrate and having the second optical pattern at least partially bonded thereto; And
And a third optical pattern formed on the upper surface of the fourth substrate. 10. The method of claim 9,
Wherein the first optical pattern is an amorphous diffusion pattern layer,
The second optical pattern is a prism layer,
And the third optical pattern is a microlens layer. The method according to claim 1,
Wherein the first substrate is thicker than the second substrate. A backlight assembly comprising a composite optical sheet according to any one of claims 1 to 11.

Images