KR20160013626A - Optical film and backlight assembly including the same - Google Patents

Abstract

Provided are an optical film and a backlight assembly including the same. The optical sheet includes: a first substrate; and a first light modulation layer formed on the upper surface of the first substrate. The first light modulation layer includes a plurality of first prism patterns. Each of the first prism pattern is extended to one direction. The prism top part of each of the first prism patterns has a curved shape along the extension direction. The vertical angle of the first prism in each of the prism top parts is constant regardless of a displacement according to the extension direction.

Description

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

The present invention relates to an optical sheet 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] As a low-power, high-brightness liquid crystal display device is required, a backlight assembly includes an optical sheet such as a prism sheet. The prism sheet has a plurality of prism patterns to condense light emitted sideways forward, thereby contributing to an increase in overall brightness.

However, repeatedly formed prism patterns may cause moire phenomenon, which may hinder display quality.

 SUMMARY OF THE INVENTION An object of the present invention is to provide an optical sheet capable of reducing the moire phenomenon while maintaining a high luminance.

Another object of the present invention is to provide a backlight assembly having a reduced moire phenomenon while maintaining a high brightness.

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 an optical sheet comprising a first substrate, and a first optical modulation layer formed on an upper surface of the first substrate, wherein the first optical modulation layer includes a plurality of first prisms, Wherein the first prism patterns extend in one direction, and the prism top portions of the first prism patterns have a wave curved shape along the extending direction, wherein the prism top portions of the first prism patterns The vertex angle is constant regardless of the displacement along the extension direction.

According to another aspect of the present invention, there is provided an optical sheet comprising a first substrate, and a first optical modulation layer formed on a top surface of the first substrate, wherein the first optical modulation layer includes a plurality of first prisms, Wherein each of the first prism patterns extends in one direction and the prism valley portions of the first prism patterns have a wave curved shape along the extending direction, The vertex angle is constant regardless of the displacement along the extension direction.

According to another aspect of the present invention, there is provided a backlight assembly including the 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 optical sheet according to the embodiments of the present invention, the moire phenomenon can be reduced while realizing high brightness.

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 perspective view of an optical sheet according to an embodiment of the present invention.
2 is a partial plan view of the optical sheet of Fig.
3 is a view showing a cross-sectional view taken along lines IIa-IIa ', IIb-IIb', and IIc-IIc 'of FIG.
Fig. 4 is a diagram showing overlapping sectional views taken along lines IIa-IIa ', IIb-IIb' and IIc-IIc 'of Fig. 2;
5 to 7 are plan views of an optical sheet according to various embodiments of the present invention.
8 is a perspective view of an optical sheet according to another embodiment of the present invention.
9 is a partial plan view of the optical sheet of Fig.
Fig. 10 is a diagram showing overlapping sectional views taken along the lines Xa-Xa ', Xb-Xb' and Xc-Xc 'in Fig. 9;
11 is a cross-sectional view of an optical sheet according to another embodiment of the present invention.
12 is a cross-sectional view of an optical sheet according to another embodiment of the present invention.
13 is a cross-sectional view of a backlight assembly according to an embodiment of the present invention.
14 is a cross-sectional view of a backlight assembly according to another 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 "sheet" can be used in the sense of " film "

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

1 is a perspective view of an optical sheet according to an embodiment of the present invention. 2 is a partial plan view of the optical sheet of Fig. 3 is a cross-sectional view taken along line IIa-IIa ', IIb-IIb', and IIc-IIc 'of FIG. 2. FIG.

1 to 4, an optical sheet 11 according to an embodiment of the present invention includes a substrate 110 and a light modulation layer formed on an upper surface of the substrate 110.

The substrate 110 may be made of a material capable of transmitting light. For example, the substrate 110 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 series, Polyvinyl alcohol series, poly norbornene series, and polyester ester series materials may be included.

The substrate 110 may have a thickness of 10 to 300 mu m, or may have a thickness of 25 to 250 mu m. In an exemplary embodiment, the thickness of the substrate 110 may be 50 占 퐉, 75 占 퐉, 125 占 퐉, or 250 占 퐉.

A back coating layer 170 may be formed on the lower surface of the substrate 110. The back coating layer 170 may have a predetermined surface roughness.

On the upper surface of the substrate 110, a first optical modulation layer is formed. The first optical modulation layer may include a plurality of prism patterns 120 extending in one direction.

The prism pattern 120 may be made of, for example, 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 prism pattern 120 may include a prism top PR_a, prism slopes PR_s1 and PR_s2, and a prism valley PR_b. The prism top PR_a may be a structure having a vertex, for example, a vertex. The prism pattern 120 may have a generally triangular cross section. The apex of the triangle corresponds to the prism top PR_a and two neighboring prism valleys PR_b.

The slope of the prism inclined downward to the left in the prism top portion PR_a is referred to as a "first prism inclined plane PR_s1" and the inclined slope downward to the right is referred to as a second prism inclined plane PR_s2. The angle made by the two prism inclined planes connected to the prism top PR_a is referred to as "prism apex angle ". The angle made by the inclined plane of the prism with the horizontal plane or the line connecting the surface of the base 110 or the adjacent prism valley PR_b is referred to as "prism inclination angle ". For convenience of explanation, the inclination angle of the prism valley PR_b connected to the first prism inclined plane PR_s1 located on the left side is referred to as a "first prism inclination angle a1", the inclination angle of the prism valley PR_b connected to the second prism inclined plane PR_s2 And the inclination angle of the valley portion PR_b will be referred to as "second prism inclination angle a2 ".

In an exemplary embodiment, the prism valleys PR_b extend in parallel along a straight line in the plan view. On the other hand, the prism top PR_a extends in the same direction as the prism valley PR_b, but has a shape of a wave curve that meanders in a direction perpendicular to the plan view extending direction, that is, in the left and right direction. When the prism top portions PR_a are arranged in a wave curve shape, when the optical sheet 11 is disposed in the liquid crystal display, the moire phenomenon that may be caused by the relative arrangement relation with the pixels can be prevented or reduced.

The wave curve shape may be a pattern that has a predetermined amplitude in the horizontal direction with respect to the reference line CL and proceeds along the extending direction. The left and right maximum displacements with respect to the reference line CL may be mutually the same. The wave curve may be a sinusoidal shape, but is not limited thereto.

The wave period T of the prism top PR_a may be constant. The wave period T of the prism top PR_a is greater than or equal to the pixel width of the liquid crystal display to be clamped, which is advantageous for preventing moire. On the other hand, if the wave period T of the prism top PR_a is too large, sufficient moiré prevention effect can not be obtained. From this point of view, the wave period T of the prism top PR_a can be from 50 μm to 500 μm, and can be about 100 μm, for example. However, the present invention is not limited to the above example, and the prism top PR_a may have a random period T or an irregular shape.

The prism valley PR_b extends straight, while the prism top PR_a has a wave and oscillates. Therefore, the cross-sectional shape of the prism pattern 120 varies depending on the position in the extending direction.

The length of the second prism inclined surface PR_s2 on the sectional view is longer than the length of the first prism inclined surface PR_s1 when the prism top portion PR_a is located on the left side with respect to the reference line CL. On the other hand, when the prism top portion PR_a is located on the right side of the reference line CL, the length of the first prism inclined surface PR_s1 on the sectional view is longer than the length of the second prism inclined surface PR_s2.

The height h of the prism can be defined as the distance from the base of the prism on the sectional view (side obtained by connecting the prism valley PR_b) to the prism top PR_a. In an exemplary embodiment, the height h of the prism can be kept constant along the extending direction of the prism. In another embodiment, the height h of the prism may be modified along the prism extension direction.

The prism apex angle can have a substantially constant value regardless of the displacement along the extension direction of the prism. When the vertex angle of the prism is about 90 °, it is advantageous to realize the maximum luminance. In this case, the triangle as the above-mentioned prism sectional shape becomes a right triangle, and the sum of the first prism inclination angle a1 and the second prism inclination angle a2 becomes about 90 degrees.

On the other hand, when the first prism inclination angle a1 and the second prism inclination angle a2 are close to about 45 degrees, the maximum brightness is exhibited. When the angle is smaller than 43 degrees or larger than 47 degrees, the brightness can be excessively reduced. Therefore, in order to maintain the high luminance quality, the first prism inclination angle a1 and the second prism inclination angle a2 may be designed to vary in the range of 43 degrees to 47 degrees.

Under the above conditions, when the first prism inclination angle a1 is 47 degrees, the prism top PR_a is located at the leftmost position. When the first prism inclination angle a1 is 45 degrees, the prism top PR_a is located at the baseline CL of the wave pattern , The prism top part (PR_a) is located at the rightmost position when it is 43 degrees. Since the amplitude w of the wave pattern means the horizontal distance, it can be obtained by the following equation (1).

[Equation 1]

w = 2 * {h * tan (? 1) - h * tan (90?

Where h is the height of the prism pattern 120 and? 1 is the first prism inclination angle a1 when the prism top PR_a is located on the reference line CL, And? 2 represents the first prism inclination angle a1 when the prism top PR_a is located at the leftmost position.

Theta] 1 when the first prism top PR_a is located on the reference line CL is 45 and the second prism top PR_a is the leftmost. It can be summarized as follows.

&Quot; (2) "

w = 2 * {h * tan45 - h * tan43}

Since the value of tan45 is 1 and the value of tan43 is about 0.93, the above equation (2) can be summarized as follows.

&Quot; (3) "

w = 0.14 * h

On the other hand, in the exemplary embodiment, the prism height h is 1/2 of the length of the prism base curve c, and in this case, the amplitude w of the wave curve can be summarized as follows.

&Quot; (4) "

w = 0.07 * c

That is, the left-right amplitude w of the prism top portion PR_a wave curve, which can reduce the moire phenomenon while maintaining the effective luminance, may be about 7% or less of the width of the prism base line c.

As described above, according to the optical sheet 11 according to the present embodiment, it is possible to maintain a high luminance quality while preventing or reducing moire phenomenon.

As another embodiment of the present invention, the first optical modulation layer including the plurality of prism patterns 120, the base material 110, and / or the back coating layer 170 may be integrally formed.

5-7 illustrate various arrangements of the prism top portion PR_a wave shape between neighboring prism patterns 120 as plan views of the optical sheet according to various embodiments of the present invention.

The wave period T of the prism peak PR_a in the neighboring prism pattern 120 may be constant. That is, the wave period T of the prism top PR_a can be uniform over the entire prism pattern 120. [

The wave curves of the prism top PR_a in the neighboring prism patterns 120 may be in a line-symmetrical relationship, as shown in Fig. 5, or may be completely the same as shown in Fig. 6 have. In the case of FIG. 5, the distance between the adjacent wave curves at the position where the wave curve has the maximum amplitude (displacement along the extension direction) becomes maximum or minimum. In the case of Fig. 6, the separation distance between neighboring wave curves is maintained uniformly regardless of the displacement along the extension direction.

7 illustrates a case where the wave curve of the neighboring prism pattern 120 is displaced downward or upward as it goes to the right. In Fig. 7, the case where the wave curve on the right side is displaced downward by 1/4 cycle compared to the wave curve on the adjacent left side is shown.

5 to 7 are similar to graphs of sine waves in which the same wave curve has the direction of extension as a variable with respect to phase. FIG. 5 shows a case where the phase of the neighboring wave curve is different by 180 °, FIG. 6 shows the case where there is no phase difference of the neighboring wave curve, and FIG. do. It goes without saying that the wave curves having various phase differences may be arranged.

Although not shown, neighboring wave curves may have a random phase difference or the cycle of the wave curve may be random. Such a random shape may be somewhat disadvantageous for precise control of light, but it may be more advantageous to prevent moire.

8 is a perspective view of an optical sheet according to another embodiment of the present invention. 9 is a partial plan view of the optical sheet of Fig. Fig. 10 is a diagram showing overlapping sectional views taken along the lines Xa-Xa ', Xb-Xb' and Xc-Xc 'in Fig. 9;

8 to 10, the optical sheet 12 according to the present embodiment is configured such that the prism top portions PR_a of the prism patterns 121 extend in parallel along a straight line in a plan view, Wave-like shape, as shown in Fig. The vertex angle of the prism top portion PR_a is maintained at a constant value such as 90 DEG and the first prism inclination angle a1 and the second prism inclination angle a2 are designed to vary in the range of 43 DEG to 47 DEG, 1 to Fig. The wave amplitude of the prism valley PR_b is also substantially the same as the wave amplitude of the prism peak PR_a described in the embodiment of Figs. In addition, the wave arrangement of the prism valley PR_b is substantially the same as the wave arrangement of the prism peak PR_a illustrated in FIGS.

Also in this embodiment, the moire phenomenon can be prevented or suppressed as the prism valley PR_b exhibits a wave curve shape while maintaining high luminance quality.

Although not shown in the figure, both the prism top PR_a and the prism valley PR_b may exhibit a wave curve on a plan view. That is, the prism top PR_a in the embodiment of FIGS. 1 to 4 and the prism valley PR_b of FIG. 8 to FIG. 10 may be applied in combination. In this case also, the prism apex angle of the prism top PR_a is kept constant, and the wave amplitudes of the prism top PR_a and the prism valley PR_b may be limited within a certain range.

11 is a cross-sectional view of an optical sheet according to another embodiment of the present invention. The optical sheet 13 shown in Fig. 11 exemplifies a case where other optical modulation layers are combined and bonded on the optical sheet 11 shown in Figs. 1 to 4.

11, the optical sheet 13 includes a first substrate 110, a first optical modulation layer formed on a top surface of the first substrate 110, a second substrate 210, A second optical modulating layer, and a bonding layer 250 formed on the lower surface of the second substrate 210, the bonding layer 250 being at least partly penetrated or tangent to the first optical modulating layer.

The first substrate 110 and the first optical modulation layer are the same as the substrate 110 and the optical modulation layer described in Figs.

The second substrate 210 may be disposed in parallel with the first substrate 110. The second substrate 210 may be made of substantially the same material as the first substrate 110.

A second light modulating layer is formed on the upper surface of the second substrate 210. The second optical modulating layer has a non-planar surface and may include recesses and protrusions. The second optical modulation layer may be a microlens pattern layer, a prism layer, or a lenticular layer, but is not limited thereto. In the drawing, a case where a prism layer 220 is applied as a second optical modulation layer is illustrated. Although the extension direction of the prism layer 220 of the second optical modulator layer is the same as that of the prism pattern 120 of the first optical modulator layer for the sake of convenience of explanation, it is apparent to those skilled in the art Do. The prism layer 220 of the second optical modulation layer may be a prism having a general shape, but the prism pattern 120 according to various embodiments described with reference to FIGS. 1 to 9 may be applied.

A bonding layer 250 is formed on the lower surface of the second base 210 and at least a part of the top of the prism pattern 120 of the first optical modulation layer is bonded or bonded to the inside of the bonding layer 250.

12 is a cross-sectional view of an optical sheet according to another embodiment of the present invention. Referring to Fig. 12, the optical sheet 14 according to the present embodiment is different from the embodiment of Fig. 11 in that the second base material 210 and the bonding layer 250 are omitted in the embodiment of Fig. In this embodiment, at least a part of the top portion of the prism pattern 120 of the first optical modulation layer penetrates or fuses to the bottom surface of the prism layer 220 of the second optical modulation layer to couple.

In the case of the embodiment of Figs. 11 and 12, since a plurality of optical modulation layers are combined and integrated, various optical modulation characteristics can be exhibited. In addition, when the prism top portion PR_a of the first optical modulation layer is applied in a wave shape, the area penetrated into the coupling layer or the second optical modulation layer is widened, and the coupling force can be further strengthened.

Hereinafter, a backlight assembly according to embodiments of the present invention employing the optical sheet as described above will be described.

13 is a cross-sectional view of a backlight assembly according to an embodiment of the present invention. 13 illustrates a case where an optical sheet according to embodiments of the present invention is employed in an edge-type backlight assembly.

13, a backlight assembly 700 according to the present embodiment includes a light source 710, a light guide plate 730 guiding light emitted from the light source 710, a reflection sheet (not shown) disposed below the light guide plate 730, A light source 710, a light guide plate 730, a reflective sheet 720, and an optical sheet 11, which are disposed on the upper side of the light guide plate 730 and modulate the optical characteristics of the emitted light, And the like. As the optical sheet 11, an optical sheet according to various embodiments of the present invention as well as the optical sheet of FIG. 1 described above can be applied.

The light source 710 is disposed on both sides of the light guide plate 730. 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 light guide plate 730.

The light guide plate 730 moves the light emitted from the light source 710 through total internal reflection and emits the light upward through a scattering pattern or the like formed on the lower surface of the light guide plate 730. A reflection sheet 720 is disposed under the light guide plate 730 to reflect the light emitted downward from the light guide plate 730 upward. Although the upper and lower surfaces of the light guide plate 730 are parallel to each other in the drawing, a wedge-shaped light guide plate having a thickness larger than that of the other side surface may be applied.

An optical sheet 11 is disposed on an upper portion of the light guide plate 730. Since the optical sheet 11 has been described in detail in the foregoing, a duplicate description will be omitted. Other optical sheets may be further arranged above or below the optical sheet 11. [ For example, a diffusion film for diffusing incident light, a prism sheet for condensing incident light, a liquid crystal film for partially reflecting the incident circularly polarized light, a retardation film for converting circularly polarized light to linearly polarized light, At least two or more combined sheets and / or a protective film may be further provided.

14 is a cross-sectional view of a backlight assembly according to another embodiment of the present invention. Fig. 14 illustrates a case where an optical sheet according to embodiments of the present invention is employed in a direct-type backlight assembly.

14, the backlight assembly 701 according to the present embodiment includes at least one light source 711 housed in a storage container 741, a storage container 741, And an optical sheet 11 disposed on the light emitting side of the light source 711. As the optical sheet 11, an optical sheet according to various embodiments of the present invention as well as the optical sheet of FIG. 1 described above can be applied.

A support plate 731 may be disposed under the optical sheet 11. The support plate 731 may be a separate shielding layer or shielding structure such as a diffusion plate, a diffusion plate, or the like, or a composite sheet in which a light diffusion layer is combined.

The storage container 741 houses at least one light source 711 and the composite optical sheet 11. The storage container 741 may include a bottom surface formed in a substantially rectangular shape and a side wall formed perpendicularly to each side of the bottom surface. A seating end on which the optical sheet 11 is seated can be provided on the side wall of the storage container 741. In the figure, a case in which the seating end is formed as a step formed on the upper side of the side wall of the receiving container 741 is exemplified. However, the entire upper end of the side wall of the receiving container 741 is formed flat, The side wall of the storage container 741 may partially extend upward from the seating end and then be bent downward.

A reflective sheet 721 may be disposed on the bottom surface of the storage container 741. A sheet supporting protrusion 750 may be disposed on the bottom surface of the storage container 741. The sheet supporting protrusions 750 serve to prevent the composite optical sheet 11 and / or the support plate 731 from being bent or struck convexly.

At least one light source 711 may be disposed on the bottom surface of the storage container 741. The light source 711 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 the drawing, an LED is shown as an example of the light source 711. [

The plurality of light sources 711 may be disposed apart from each other. When a plurality of light sources 711 are LEDs that are point light sources, each LED may be arranged according to a certain array rule in the matrix direction. For example, the LEDs may be arranged at equal intervals in the matrix direction, and the LEDs may be arranged in three rows, but the numbers are different for each row, such as five for the first row, seven for the second row, six for the third row Lt; / RTI > However, it goes without saying that the present invention is not limited to the above exemplified arrangement.

In the case of the backlight assembly according to the above-described embodiment, by providing the optical sheet according to the embodiments of the present invention, moire phenomenon can be reduced while realizing high brightness.

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.

200: Optical sheet
211: first substrate
212: second substrate
230 prism layer
231:
232: upper wave pattern portion
250: Micro lens layer

Claims (17)

A first substrate; And
And a first optical modulation layer formed on the upper surface of the first substrate,
Wherein the first optical modulation layer includes a plurality of first prism patterns,
Wherein each of the first prism patterns extends in one direction,
Wherein a prism top of each of the first prism patterns has a wave curve shape along an extending direction,
Wherein an apex angle of the first prism pattern at each apex of the prism is constant regardless of a displacement along the extending direction. The method according to claim 1,
Wherein the wave curve is formed with a constant amplitude and period along the extending direction. The method according to claim 1,
And the amplitude of the wave curve is about 0.07 times or less the width of the base of the prism pattern. The method according to claim 1,
Wherein each of the first prism patterns includes a first prism inclined surface inclined downward from the prism top portion to one side and a second prism inclined surface inclined downward to the other side,
Wherein the prism inclination angle of the first prism inclined surface and the inclination angle of the prism of the second prism inclined surface vary in the range of 43 to 47 degrees. The method according to claim 1,
And the prism valley portion of the first prism pattern extends in a straight line along the extending direction. The method according to claim 1,
A second substrate disposed on the first substrate; And
And a bonding layer disposed on the lower surface of the second substrate,
Wherein the prism top portion of the first prism pattern at least partly penetrates or abuts to the bonding layer. The method according to claim 6,
And a second optical modulation layer formed on the second substrate. 8. The method of claim 7,
Wherein the second optical modulation layer includes a second prism pattern,
Wherein the prism top of the second prism pattern has a wave curved shape along the extending direction and the second prism apex angle at the top of the prism of the second prism pattern is constant irrespective of the displacement along the extending direction. The method according to claim 1,
Further comprising a second light modulating layer disposed on top of the first substrate and at least partially penetrating or engaging the prism top of the first prism pattern through the bottom surface,
The second optical modulation layer includes a second prism pattern,
Wherein the prism top of the second prism pattern has a wave curved shape along the extending direction and the second prism apex angle at the top of the prism of the second prism pattern is constant irrespective of the displacement along the extending direction. A first substrate; And
And a first optical modulation layer formed on the upper surface of the first substrate,
Wherein the first optical modulation layer includes a plurality of first prism patterns,
Wherein each of the first prism patterns extends in one direction,
Wherein the prism valley portions of the first prism patterns have a wave curved shape along the extending direction,
Wherein an apex angle of the first prism pattern at each apex of the prism is constant regardless of a displacement along the extending direction. 11. The method of claim 10,
Wherein the wave curve is formed with a constant amplitude and period along the extending direction. 11. The method of claim 10,
Wherein each of the first prism patterns includes a first prism inclined surface inclined downward from the prism top portion to one side and a second prism inclined surface inclined downward to the other side,
Wherein the prism inclination angle of the first prism inclined surface and the inclination angle of the prism of the second prism inclined surface vary in the range of 43 to 47 degrees. 11. The method of claim 10,
Wherein the prism top portion of the first prism pattern extends straight along the extending direction. 11. The method of claim 10,
Wherein the prism top portion of the first prism pattern has a wave curved shape along the extending direction. 11. The method of claim 10,
A second substrate disposed on the first substrate;
A second light modulating layer formed on the second substrate;
And a bonding layer disposed on the lower surface of the second substrate,
Wherein the prism top portion of the first prism pattern at least partly penetrates or abuts to the bonding layer. 11. The method of claim 10,
And a second light modulating layer disposed on the first substrate and at least partially penetrating or bonding the prism top portion of the first prism pattern through the bottom surface. A backlight assembly comprising an optical sheet according to any one of claims 1 to 16.

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