KR101629887B1 - Optical sheet and back light unit including the same - Google Patents

Abstract

An optical sheet that can be employed in a display device such as a liquid crystal display device, and a backlight unit and a display device having the same. The optical sheet has a base layer, a pattern layer formed in a concavo-convex pattern on the base layer, and a plurality of irregularly arranged columns formed on the pattern layer so as to protrude higher than the height of the pattern layer. According to this optical sheet structure, when laminated with another optical sheet, damage to the scratch and the pattern layer can be prevented, and the luminance can be improved. And the backlight unit and the display device have at least one such optical sheet.

Optical, sheet, backlight, liquid crystal display

Description

TECHNICAL FIELD [0001] The present invention relates to an optical sheet and a backlight unit having the optical sheet.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sheet that can be employed in a liquid crystal display and a backlight unit (BLU) having the optical sheet.

Conventionally, a flat panel display (FPD) can be broadly classified into a light emitting type and a light receiving type. Examples of the light emitting type include a plasma display panel (PDP) and a field emission display (FED), and a light receiving type is a liquid crystal display (LCD). As such, since the liquid crystal display device is a light receiving type that can not emit light itself, a backlight unit (BLU) is required as an external light source.

The backlight unit includes a lamp, a diffusion sheet, a prism sheet, and the like. The lamp functions as a light source for emitting light. The diffusing sheet diffuses the light evenly and spreads it, and the prism sheet allows the light to refract and collect. In addition to the diffusion sheet and the prism sheet, an optical sheet for improving brightness, uniformity, or preventing moire phenomenon may be laminated on the prism sheet.

In general, the prism sheet is repeatedly formed with protruding portions in which triangular prisms are laid on the surface facing the liquid crystal panel so as to refract and collect light. Accordingly, if the optical sheet is laminated on the upper part of the prism sheet, scratches may be generated on the lower surface of the optical sheet by the sharp ends of the protrusions, or the protrusions may be damaged due to scratches. Damage of a pattern such as a projection or scratch on the upper sheet due to the damage can occur not only in a prism sheet but also in a lens-like pattern or a lenticular sheet.

Such a scratch phenomenon or damage to protrusions may cause optical interference, which may cause the prism sheet to appear cloudy. In order to prevent this, the lower surface of the optical sheet may be coated. In this case, however, it may be an increase in the number of processes and a rise in cost.

On the other hand, when the lamp is installed on the side portion of the backlight unit, that is, the edge type backlight unit may further include a reflective sheet and a light guide plate. The reflective sheet is for reflecting the light emitted from the lamp toward the screen of the liquid crystal panel. The light guide plate is for guiding and dispersing the light emitted from the lamp and the light reflected from the reflective sheet to the entire screen of the liquid crystal panel. The above-mentioned optical sheets are laminated on top of the light guide plate.

However, wet-out phenomenon may occur between the light guide plate and the optical sheet in the process of stacking the optical sheet on the light guide plate. Infiltration phenomenon refers to a phenomenon in which moisture penetrates and gets wet, and optical interference may occur due to infiltration phenomenon. In order to prevent this, there is a coating treatment on the lower surface of the optical sheet, which causes an increase in the number of steps and a rise in cost.

In addition, the direct type backlight includes a diffusing plate for diffusing light instead of the light guide plate. The above-described problems may also occur in the process of stacking the optical sheets on the diffusion plate.

On the other hand, if the luminance of the light transmitted from the backlight unit to the screen of the liquid crystal panel is low, the bright color expression may be deteriorated. Therefore, efforts to maximize the luminance will be needed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an optical sheet which can prevent damage to a scratch and a pattern layer when stacking a plurality of optical sheets, An optical sheet and a backlight unit having the same.

According to an aspect of the present invention, there is provided an optical sheet comprising: a base layer; A pattern layer formed on the base layer in a concavo-convex pattern; And a plurality of columns formed on the pattern layer so as to protrude higher than the height of the pattern layer.

According to another aspect of the present invention, there is provided a backlight unit including: a lamp that emits light; A light guide plate for guiding light emitted from the lamp; A base layer, a pattern layer formed on the base layer in a concavo-convex pattern, and a pattern layer formed on the pattern layer so as to protrude higher than the height of the pattern layer, wherein the base layer is formed on the light guide plate to diffuse or collect light incident from the light guide plate. A first optical sheet having a plurality of columns; And a second optical sheet laminated on the first optical sheet.

According to another aspect of the present invention, there is provided a backlight unit including: a lamp that emits light; A diffusion plate for diffusing light emitted from the lamp; A base layer; a pattern layer formed on the base layer in a concavo-convex pattern; and a projection layer projecting above the height of the pattern layer on the pattern layer, wherein the projection layer is formed on the diffusion layer, A first optical sheet having a plurality of columns formed therein; And a second optical sheet laminated on the first optical sheet.

A display device according to an embodiment of the present invention includes a light source for emitting light; A light guide plate for guiding light emitted from the light source and / or a diffusion plate for diffusing light emitted from the light source; A base layer; a pattern layer formed on the base layer in a concavo-convex pattern; and a plurality of irregularly arranged columns arranged on the pattern layer so as to protrude higher than the height of the pattern layer, A first optical sheet having a first optical sheet; And a display panel stacked on the first optical sheet.

According to the present invention, since the protruding portions of the pattern layer in the lamination with the other optical sheet are not in contact with the other optical sheet, scratches can be generated on the lower surface of the other optical sheet or damage to the pattern layer due to scratches can be prevented have. In addition, since an air layer can be formed between the protruding portion of the pattern layer and another optical sheet, brightness enhancement can be achieved.

According to the present invention, since the air layer can be formed between the light guide plate and the optical sheet or between the diffusion plate and the optical sheet in the process of laminating the optical sheet on the light guide plate or the diffusion plate, infiltration phenomenon can be prevented, Brightness enhancement can be achieved.

In addition, according to the present invention, there is no need to coat the lower surface of the optical sheet to prevent scratches or infiltration phenomenon as in the conventional art, so that an increase in the number of steps and cost increase due to the coating treatment can be solved have.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of an optical sheet according to a first embodiment of the present invention. 2 is a plan view of an example of the optical sheet shown in Fig.

Referring to FIGS. 1 and 2, an optical sheet 100 according to a first embodiment of the present invention includes a base layer 110, a pattern layer 120, and columns 130.

The base layer 110 functions as a base on which the pattern layer 120 and the columns 130 can be formed. The base layer 110 has a film thickness of a certain thickness. The base layer 110 is made of a material capable of transmitting light. For example, the base layer 110 may be made of polyethylene terephthalate (PET) or the like.

The pattern layer 120 is formed in a concave-convex pattern on the base layer 110. In this embodiment, the concavo-convex pattern is disclosed as a prism pattern 121 that can collect light by refracting light, but the concavo-convex pattern is not limited thereto. For example, the concavo-convex pattern may be a pattern selected from patterns having various optical effects such as a condensing pattern such as a prism, a diffusion pattern such as a lens, a lenticular pattern, a pyramid pattern, or the like, . Hereinafter, for convenience of explanation, the case where the pattern layer 120 is the prism pattern 121 is described as an example, but it is apparent to those skilled in the art that the present invention can be applied to other patterns as described above.

The prism patterns 121 may be formed in various patterns in a range capable of refracting and collecting light. For example, the prism pattern 121 may be a pattern in which the protrusions 121a in which the triangular prisms are laid out, that is, the protrusions 121a having the triangular profile in the longitudinal direction are repeatedly arranged. The top of the protrusion 121a in the prism pattern 121 becomes a mountain, and the point where the adjacent protrusion 121a meets becomes a valley. And the line connecting this mountain and the goal becomes a beveled face. The pattern layer 120 may be made of an adhesive resin having a predetermined refractive index and transmittance. Meanwhile, the pattern layer 120 may be formed of the same material as the base layer 110, but is not limited thereto. Also, the columns 130 may be formed of the same material as the pattern layer 120, but the present invention is not limited thereto.

Each of the columns 130 includes a plurality of columns 130a, 130b, and 130c, and each column 130 is formed to protrude above the pattern layer 120 on the pattern layer 120. Here, the height of the pattern layer 120 is defined as the height of the protrusion 121a. The columns 130 support other optical sheets 10, such as a diffusion sheet or a protective sheet, when they are stacked on the pattern layer 120. And the projected upper surface of each of the columns 130 abuts the lower surface of the other optical sheet 10 so that the pattern layer 120 does not contact the other optical sheet 10. [

Therefore, the columns 130 can prevent the protrusion 121a from being damaged due to scratches on the lower surface of the other optical sheet 10 due to the sharp ends of the protrusions 121a of the pattern layer 120, or scratches do. As a result, as in the prior art, it is not necessary to apply the coating treatment to the lower surface of the other optical sheet 10, so that the increase in the number of steps and cost increase due to the coating treatment can be solved.

In addition, the columns 130 form an air layer between the protrusions 121a and the other optical sheet 10, so that the brightness can be improved. That is, light is collected on the exit surface of another optical sheet 10 by light recirculation and light refraction while moving to another optical sheet 10 having a relatively high density through a relatively low-density air layer, Lt; / RTI >

The columns 130 may be arranged regularly, but may be randomly arranged randomly. The density of the column 130, in which the columns 130 are regularly or irregularly arranged, is preferably within a predetermined range, as described below. When the columns 130 are regularly arranged, they may have a microscopic but optical effect, resulting in a deterioration of the brightness or a nonuniform brightness distribution as a whole. Also, the regularly arranged columns 130 may be visually recognized by the observer. On the other hand, if the columns 130 are arranged irregularly, the problem of luminance deterioration and luminance unevenness does not appear, and a moire phenomenon or the like can be avoided. And irregularly arranged columns 130 are not visually perceived by the user.

In this case, the columns 130 may be distributed in all of the mountains, bones, and bevels of the prism pattern 121, or may be distributed in only one of the mountains, bones, and bevels, or in a combination of the two . Here, the 'acid' of the prism pattern indicates a portion having a vertex in each prism shape, and the 'bone' indicates a recess between the neighboring prism and the prism. The 'oblique face' means the prism's 'mountain' Indicates the connecting slope. 3 (a) is a cross-sectional view showing a case where the columns 130 are distributed on both the mountain, the bone, and the oblique surface of the prism pattern 121, and (b) to (d) are cross-sectional views showing the case where the columns 130 are distributed only on the mountain, the oblique surface, and the valley of the prism pattern 121, respectively. However, since the scratch phenomenon occurs in the protrusion 121a of the prism pattern 121, it is more effective when the columns 130 are formed on the surface of the prism pattern 121. [ It is apparent to those skilled in the art that the same can be applied to the case where the pattern layer 120 is a pattern other than a prism pattern.

The columns 130 may have flat surfaces at their protruding ends. This is to prevent scratches on the lower surface of the other optical sheet 10 by the columns 130 or damage to the column 130 due to scratches. In this case, the columns 130 may have the entire surface of the end made flat or only the edge of the flat surface rounded. An example of a shape in which the front surface of the end portion of the columns 130 is formed as a flat surface or a part of the flat surface is rounded at an edge is shown in FIG. 4, (a) shows a case where the entire front surface of the end portion of the column 130 is made of a flat surface, (b) shows that a part of the end surface of the column 130 is made flat, It is understood that the case has the shape of an arc having a predetermined radius R. In the case of Fig. 4 (b), the radius R may be within the range of 0.4 to 15 mu m.

And the protruding ends of the columns 130 may include a planar surface and an optical structure formed thereon. In this case, the added optical structure may be integrated with or separated from the flat surface. Referring to Figures 130a and 130b of Figure 1, the optical structure may be in the form of a microlens. However, the optical structure is not limited thereto, but may be a scattering structure or the like in addition to those shown.

On the other hand, the end portion of the column can be an optical structure such as a semi-spherical lens or the like, as well as the projecting end thereof is a flat surface, as shown by reference numeral 103c in Fig. It is also possible that the columns having various end shapes are arranged in a mixed manner as shown in Fig. The shape of the column 130 may vary, and for example, the cross-section may be a shape having a circular shape, a polygonal shape, or the like. In this case, the columns 130 may all have the same shape, but it is also possible that a column having a circular cross section and a column having a polygon are arranged on the pattern layer 110 in a mixed manner.

5 is a perspective view showing the shape of the column 130 according to another embodiment of the present invention. Referring to FIG. 5, the column 130 according to the present embodiment is not of a cylindrical shape but of a bar type. The bar-type columns 130 may be distributed only on the mountain, bone, and bevel surfaces of the prism patterns 121, or may be distributed in two or more of them. Such bar columns 130 may be arranged regularly or irregularly on the entire surface. The column 130 of the bar type may also have a flat top surface or an additional optical structure on the flat surface.

The length L of the bar-type column 130, that is, the length L of the bar is not particularly limited. For example, the length L of the bar may be equal to or less than the length of the prism pattern 121. In the latter case, only one column 130 having a predetermined length L in one prism pattern 121 may be disposed, or a plurality of columns 130 may be disposed in a dispersed manner. Also, the length L of all the columns 130 need not always be the same, and bars having different lengths may be mixed. It is apparent to those skilled in the art that, even in the case of the bar-type column 130, the total density of the column is preferably within the range described later.

1, the column 130 may have a vertical columnar shape (i.e., the width of the transverse section of the upper end portion is the same as that of the lower end portion), but the cross section of the upper end portion may be smaller than the width of the transverse section of the lower end portion Shape, that is, a shape having a predetermined inclination such as a pyramid, a cone, or the like. 6A and 6B are diagrams for explaining the shape of a column having a predetermined inclination in a side surface as shown in FIG. 6A. FIG. 6A is a diagram showing a case where the column 130 is a pyramid- Shape. Thus, even in the case of the column 130 having a predetermined inclination on the side surface, the edge of the upper surface may be rounded and / or the optical structure may be further formed on the flat surface. The shape of the column as shown in FIG. 6 is excellent in the releasing property in the imprinting process, so that the productivity of the optical sheet 100 can be improved by increasing the process speed of the optical sheet 100.

As the height of the column 130 is lowered, the scratch prevention effect is lowered. On the other hand, as the height of the column 130 increases, the gap between the optical sheet 100 and the other optical sheet 10 becomes wider, which may increase the thickness of the laminate. Table 1 thus shows the relationship between the height of the column 130 and the acid strength. Referring to Table 1, as the height of the barrier ribs increases, the acid strength increases. In consideration of the lamination thickness, the height of the column 130 is set to be higher than the height of the pattern layer 120 within a range of 0.5 to 50 μm desirable.

Column height 0.5-2 (탆) 2-6 (占 퐉) 6-8 (탆) 8-10 (占 퐉) 10-20 (탆) 20-50 (탆) Mountain road 15 (g) 20 (g) 100 (g) 180 (g) 230 (g) 300 (g)

The lower the distribution density of the columns 130, the lower the scratch resistance, and the lower the distribution density of the columns 130, the lower the luminance. The distribution density of the columns 130 is defined as the area occupied by the columns 130 relative to the total area of the pattern layer 120. In the optical sheet 100 according to the present embodiment, the correlation between the distribution density of the columns 130 and the luminance can be expressed by Equation (1).

G '= 1+ (G-1)? (1-d) = G- (G-1)

Here, d represents the distribution density of the column, G represents the luminance improvement rate (Gain) of the optical sheet without the column, and G 'represents the luminance improvement rate of the optical sheet having the column with the distribution density d. For example, G 'is 1.495 when the distribution density (d) of the column is 1% in the optical sheet having G of 1.5 and 1.485 when the distribution density (d) is 3%. By appropriately using the correlation between the distribution density (d) of such a column and the luminance improvement rate, the distribution density of the optimum column can be determined according to the application.

Table 2 and Table 3 show the relationship between the distribution density, the acidity, the distribution density and the luminance of the columns 130 (in Table 3, the luminance is the relative luminance as compared with the optical sheet in the absence of the column 130 ). Referring to Table 2, it can be seen that acid strength increases as the distribution density of the columns 130 increases. Referring to Table 3, it can be seen that the overall brightness decreases as the distribution density of the columns 130 increases. Therefore, it is preferable that the distribution density of the columns 130 is determined within an appropriate range in consideration of the increase of the acid intensity and the decrease of the luminance.

Density of column 0.05 (%) 0.2 (%) 0.55 (%) 1.1 (%) 2(%) 2.5 (%) 20 (%) 35 (%) Mountain road 70 100 180 610 630 655 670 700

Density of column 0.05 (%) 0.2 (%) 0.55 (%) 1.1 (%) 2(%) 2.5 (%) 20 (%) 35 (%) Brightness (%) 99.94 99.86 99.63 99.26 98.66 98.33 93.33 76.66

The present inventors have found through numerous experiments that if the distribution density of the columns 130 is less than 0.05%, the acid strength is not sufficient and the column 130 does not act as a support layer, and conversely, the distribution density of the columns 130 It has been found that the luminance decreases sharply when it is a constant level, for example, 35% or more. Based on these experiments, it is preferred that the distribution density of the columns 130 be set within the range of 0.05% to 35%. Here, the distribution density of a column refers to a ratio of "area of columns arranged in the optical sheet" to "total area of optical sheet ".

It is preferable that the maximum width of the column 130 is set within a range of 0.5% to 500% with respect to the pitch between the protrusions 121a of the pattern layer 120. The maximum width of the column 130 with respect to the pitch of the pattern layer 120 is related to whether or not the column 130 is visible in the finished product BLU. More specifically, if the width of the column 130 exceeds 500% of the pitch of the pattern layer 120, sparkling due to the column 130 may occur, resulting in apparent defects. Conversely, if the width of the column 130 falls below 0.5% of the pitch of the pattern layer 120, the aspect ratio of the column becomes high, causing a problem in the manufacturing process (problem of releasing the column during the transfer of the column) You can. For example, the maximum width of the column 130 may be set within a range of 0.2 to 500 mu m, and the pitch between the columns 130 may be set within a range of 10 to 1000 mu m.

The pattern layer 120 and the columns 130 may be formed by applying a resin solution on the base layer 110 and curing the resin solution while pressing the applied surface with a master mold. Since the master mold can be manufactured by laminating the column forming mold on the base substrate again on the forming die for the pattern layer, the forming mold for the column can be formed more precisely have. Thus, when forming the columns 130 by the master mold, it may be advantageous to form the columns 130 more uniformly.

A diffusion pattern 131 may be further formed on the protruding end of the column 130. The diffusion pattern 131 is an example of the above-described optical structure. The diffusing pattern 131 diffuses the light passing through the column 130 so that it can be incident on the other optical sheets 10 stacked thereon as evenly as possible. Therefore, when employed in the backlight unit, the optical sheet 100 having the above-described configuration can contribute to increase the light efficiency of the backlight unit. The diffusing pattern 131 may be various. For example, the diffusing pattern 131 may be a pattern in which a plurality of convex lens-shaped convex portions are arranged so as not to cause scratches on the lower surface of the other optical sheet 10, .

FIG. 7 is a cross-sectional view of an optical sheet according to a second embodiment of the present invention, and FIG. 8 is a plan view of an example of the optical sheet shown in FIG. Hereinafter, the second embodiment will be described focusing on the difference from the optical sheet according to the first embodiment described above. The contents which are not explained in detail in this embodiment can be applied to this embodiment, except that the above-mentioned contents in the first embodiment can not be applied by their nature.

7 and 8, in the optical sheet 200 according to the second embodiment of the present invention, the concave-convex pattern of the pattern layer 220 formed on the base layer 210 is formed of the microlens pattern 221. The base layer 210 has a film thickness of a certain thickness and is made of a material capable of transmitting light. The base layer 210 may be made of polyethylene terephthalate or the like.

The microlens patterns 221 can be formed in various shapes in a range that can diffuse light evenly. For example, the micro lens pattern 221 may be a pattern in which convex micro lenses 221a are repeatedly arranged. Here, the micro lens 221a means a lens having a microscopic size in micro units. The microlens 221a may have a circular cross-section, but may also be elliptical.

The microlens patterns 221 may have a pattern in which microlenses of the same size are arrayed. However, as shown in the figure, microlenses of different sizes may be formed in a mixed pattern so as to maximize the diffusion effect. have.

The pattern layer 220 may be made of an adhesive resin or the like having a predetermined refractive index and transmittance, as with the pattern layer 120 of the first embodiment described above. In addition, the pattern layer 220 may be made of the same material as the base layer 210, but may be made of the same material.

The columns 230 are formed in a plurality of columns, and each of the columns 230 is formed to protrude above the height of the pattern layer 220 on the pattern layer 220. Here, the height of the pattern layer 220 is defined as the height of the microlenses having the maximum height among the microlenses 221a. It is preferable that an optical structure such as the diffusion pattern 231 is formed on the protruding end of the column 230 like the column 130 of the first embodiment described above. In addition, the column 230 of the present embodiment may be configured in the same or similar form as the column 130 of the first embodiment described above.

Each of the columns 230 has a protruded upper surface that abuts on the lower surface of the other optical sheet 20 to form a pattern layer 220 ) Does not come into contact with the other optical sheet (20). Accordingly, the columns 230 can prevent scratches on the lower surface of another optical sheet 20 by the microlenses 221a, or damage to the microlenses 221a due to scratches.

In addition, when the prism sheet is stacked as another optical sheet 20 on the upper part of the columns 230, the columns 230 change the optical path incident on the prism sheet, thereby enhancing the efficiency of light condensed in the prism sheet. This will be described with reference to FIGS. 9 and 10. FIG. Here, FIG. 9 is a view showing an optical path according to this embodiment, and FIG. 10 is a view showing an optical path according to a comparative example.

As shown in Figs. 9 and 10, the comparative example has a structure in which columns 230 are omitted in this embodiment. In the comparative example, the angle of incidence of the light totally reflected while passing through the prism sheet and the light diverged from the exit surface of the prism sheet by the column 230 according to the present embodiment is changed, It is possible to diverge in a direction perpendicular to the exit surface of the sheet.

Therefore, the present embodiment can increase the efficiency of light condensed in the prism sheet as compared with the comparative example. In addition, since the fill factor can be increased by the columns 230 of the present embodiment, the light efficiency may be increased. Here, the fill factor means the ratio of the area occupied by the microlenses 221a and the columns 230 in the entire area of the optical sheet 200. [

When such an optical sheet 200 is employed in a liquid crystal display device, the brightness of light transmitted from the backlight unit to the screen of the liquid crystal panel can be further increased. Accordingly, the optical sheet 200 of this embodiment can contribute to enhancement of bright color expressive power.

11 is a sectional view of a backlight unit according to an embodiment of the present invention, which is an edge type backlight unit.

11, a backlight unit 1000 according to an embodiment of the present invention includes a lamp 1100, a light guide plate 1200, a first optical sheet 1300, and a second additional optical sheet 1400 . A reflective sheet 1500 is provided at the lowermost end of the backlight unit 1000.

The lamp 1100 emits light as a light source. The light guide plate 1200 functions to guide and disperse light emitted from the lamp 1100 when the lamp 1100 is installed on a side portion of the backlight unit 1000. [ For example, when the backlight unit 1000 is employed in a liquid crystal display device, the light guide plate 1200 can guide and disperse the light emitted from the lamp 1100 to the entire screen of the liquid crystal panel. In this case, the reflective sheet 1500 is further provided, and the light emitted from the lamp 1100 can be reflected toward the screen of the liquid crystal panel.

The first optical sheet 1300 diffuses or collects the light incident from the light guide plate 1200. Here, the first optical sheet 1300 may be configured as the optical sheet 100 according to the above-described first embodiment, or may be configured as the optical sheet 200 according to the second embodiment described above. That is, the concavo-convex pattern of the first optical sheet 1300 may be a pattern selected from patterns having various optical effects such as a condensing pattern such as a prism, a diffusion pattern such as a lens, a lenticular pattern, a pyramid pattern, It can be a mixed composite pattern.

When the first optical sheet 1300 is constructed as the optical sheet 100 according to the first embodiment or the optical sheet 200 according to the second embodiment described above, When the additional optical sheet 1400 is laminated, the effects described in the first and second embodiments can be exerted. On the other hand, the second additional optical sheet 1400 may be a prism sheet, a diffusion sheet, a protective sheet, a micro lens sheet, a lenticular sheet, or the like.

The first optical sheet 1300 is stacked on the light guide plate 1200 to diffuse or collect light incident from the light guide plate 1200 and to provide the light to the liquid crystal panel. Here, the light guide plate 1200 is formed such that spacers 1210 protrude from the surface on which the first optical sheet 1300 is stacked. The spacers 1210 prevent infiltration between the light guide plate 1200 and the first optical sheet 1300 in the process of stacking the first optical sheet 1300 on the light guide plate 1200. This spacer 1210 is only different in name from the 'column' in the above embodiment, and its function is essentially the same as the column.

Therefore, according to this embodiment, optical interference due to the infiltration phenomenon can be prevented. In order to prevent the infiltration phenomenon, the lower surface of the first optical sheet 1300 is not required to be subjected to the coating treatment as in the prior art, so that the increase in the number of steps and cost increase due to the coating treatment can be solved.

In addition, the spacers 1210, i.e., the columns, form an air layer between the first optical sheet 1300 and the light guide plate 1200, thereby improving brightness. That is, light incident from the light guide plate 1200 passes through a relatively-low-density air layer and moves to the first optical sheet 1300 having a relatively high density, and light emitted from the first optical sheet 1300 due to light recirculation and light refraction The brightness can be improved.

On the other hand, the shape, size, height, distribution, and the like of the spacer 1210, that is, the column, can be variously configured within the range in which the above-described effects can be exhibited.

In another embodiment of the present invention, the backlight unit may include a diffusion plate for diffusing light emitted from the lamp 1100 instead of the light guide plate 1200, and a lamp 1100 may be disposed directly below the diffusion plate It may be a direct-type backlight unit installed. The diffusion plate may be formed on the surface on which the first optical sheet 1300 is stacked, such that the spacers 1210, i.e., the columns are protruded as in the above-described embodiment. The effect of this is as described above.

12A to 12E are views showing a sheet stacking configuration in a backlight unit according to another embodiment of the present invention and a configuration of a display device including the backlight unit. In this embodiment, a laminated structure of sheets constituting a backlight unit of a display device will be mainly described. Items not described here can be applied to the general structure of the display device and the same contents as described above with reference to FIG.

12A to 12E, the display device includes a display panel P and a backlight unit BLU. The display panel P is an apparatus for displaying an image by receiving light from a backlight unit (BLU), and may be a non-emissive device such as an LCD panel, not a self-emissive device. There is no particular limitation on the type of the display panel P, and it may be an LCD panel to be used in the future as well as a currently used LCD panel. The backlight unit BLU may be an edge type backlight unit in which the light source L is positioned on the side of the display panel P or a direct backlight unit in which the light source L is located under the display panel P. [ There is no particular limitation on the type of the light source, and the light source may be a light emitting diode (LED) or an organic light emitting diode (OLED) as well as a lamp.

12A and 12B relate to an edge type backlight unit in which the light source L is located on the side surface of the panel P. 12A, the backlight unit includes a reflective sheet S5, a light guide plate S4, a second additional optical sheet S3, and a first optical sheet S2 from the bottom thereof, and the first optical sheet S2 The panel P is positioned on the upper side of the panel P. 12B, a reflective polarizing sheet and / or a third additional optical sheet S1 are additionally provided between the first optical sheet S2 and the panel P, as compared with the backlight unit shown in FIG. 12A . 12A and 12B, the concavo-convex pattern of the first optical sheet S2 and the second additional optical sheet S3 may be formed by various optical effects such as a condensing pattern such as a prism, a diffusion pattern such as a lens, a lenticular pattern, a pyramid pattern, , Or a composite pattern of two or more of them. In addition, either the first optical sheet S2 and the second additional optical sheet S3 may include either the columns or spacers of the present invention, or both columns may include columns or spacers. And optionally, the light guide plate S4 may also include a column, in which the light guide plate S4 may be replaced with a diffuser plate, or a diffuser plate may be added. The diffuser plate may also include a column such as a light guide plate. On the other hand, the arrangement order of the first optical sheet S2 and the second optical sheet S3 can be selected and arranged in consideration of various optical characteristics, so that the second optical sheet S3 can be arranged in the first optical sheet S2, or, alternatively, the second optical sheet S3 may be disposed on the first optical sheet S2.

Like the first and second optical sheets, the third additional optical sheet S1 is formed of a pattern having various optical effects such as a condensing pattern such as a prism, a diffusion pattern such as a lens, a lenticular pattern, a pyramid pattern, A single pattern, or a sheet having a composite pattern in which two or more are mixed.

On the other hand, when the third additional optical sheet or the reflective polarizing sheet is to be arranged as the first and second additional optical sheets, the order of arrangement can be variously considered.

12C, 12D, and 12E relate to a direct-type backlight unit in which the light source L is positioned below the panel P. FIG. 12C, a reflective sheet S5 is disposed under the light source L, and the diffusion plate S4, the second additional optical sheet S3, and the first And an optical sheet S2, and the panel P is disposed on the first optical sheet S2. 12D and 12E, a reflective polarizing sheet S1 and another second additional optical sheet S1 are provided between the first optical sheet S2 and the panel P, as compared with the backlight unit shown in FIG. Sheet S3 is further included. 12C to 12E, the first optical sheet S2 and the second additional optical sheet S3 are sheets having various optical functions such as a diffusion sheet, a prism sheet, a micro lens sheet, or a lenticular sheet, May include more than one sheet. And the first optical sheet S2 and the second additional optical sheet S3 may include only one of the two columns, or both of the two sheets may include the column of the present invention. Optionally, the diffuser plate S4 may also include a column, in which the diffuser plate S4 may be replaced by a light guide plate, or a light guide plate may be added. The diffuser plate may also include a column such as a light guide plate.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation and that those skilled in the art will recognize that various modifications and equivalent arrangements may be made therein. It will be possible. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

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

2 is a plan view of an example of the optical sheet shown in Fig.

3 is a cross-sectional view illustrating an exemplary distribution of columns in an optical sheet according to an embodiment of the present invention.

4 is a cross-sectional view showing examples of end shapes of a column according to an embodiment of the present invention.

5 is a perspective view showing a bar type column in an optical sheet according to an embodiment of the present invention.

6 is a perspective view showing a shape of a column having a predetermined inclination in a side surface according to an embodiment of the present invention.

7 is a cross-sectional view showing an optical sheet according to a second embodiment of the present invention.

8 is a plan view of an example of the optical sheet shown in Fig.

9 is a view showing an optical path according to the optical sheet shown in Fig.

10 is a view showing an optical path according to a comparative example for comparison with the optical path of FIG.

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

12A to 12E are sectional views showing a laminated structure of sheets in a backlight according to another embodiment of the present invention, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

Base layer 120.220 .. Pattern layer

121. A prism pattern 121a.

130, 230 .. column 131 .. spreading pattern

221 .. Micro lens pattern 221a .. Micro lens

1100 .. light source 1200 .. light guide plate

1210 .. Spacer

Claims (63)

A base layer; A pattern layer formed on the base layer in a concavo-convex pattern; And A plurality of irregularly arranged columns formed on the pattern layer so as to protrude higher than a height of the pattern layer; And, The protruding end of the column is made of a flat surface, Wherein a diffusion pattern, a hemispherical lens, or a microlens is further formed on the flat surface of the column. delete delete The method according to claim 1, Wherein the column has a rounded edge at the flat surface. 5. The method of claim 4, Wherein an edge of the flat surface is an arc having a radius R of 0.4 to 15 占 m. A base layer; A pattern layer formed on the base layer in a concavo-convex pattern; And And a plurality of irregularly arranged columns formed on the pattern layer so as to protrude higher than a height of the pattern layer, Wherein the column has a protruding end itself formed in a shape of a diffusion pattern, hemispherical lens, or microlens. The method according to claim 1, Wherein the height of the column is set to be higher than a height of the pattern layer within a range of 0.5 to 50 占 퐉. The method according to claim 1, Wherein the distribution density of the column is set within a range of 0.05% to 35%. The method according to claim 1, Wherein a maximum width of the column is set within a range of 0.5% to 500% with respect to a pitch of the pattern layer. 10. The method of claim 9, Wherein the maximum width of the column is set within a range of 0.2 탆 to 500 탆. The method according to claim 1, And the pitch between the columns is set within a range of 10 탆 to 1000 탆. The method according to claim 1, Wherein the concavo-convex pattern is a prism pattern capable of collecting light by refracting light. 13. The method of claim 12, Wherein the column is formed on only one of the mountain, the valley, and the oblique surface of the prism pattern, or is randomly formed on the mountains, valleys, and oblique faces of the prism pattern. The method according to claim 1, Wherein the concavo-convex pattern is a microlens pattern. The method according to claim 1, Wherein the column is formed in at least one of a circular cross-section and a polygonal cross-section. The method according to claim 1, Wherein the concavo-convex pattern is a pattern selected from a condensing pattern, a diffusion pattern, a lenticular pattern, and a pyramid pattern, or a composite pattern in which two or more patterns are mixed. The method according to claim 1, Wherein an area of the cross section at the lower end of the column is wider than an area of the cross section at the upper end. The method according to claim 1, Wherein the column is a bar type. A light source for emitting light; And A base layer, a pattern layer formed on the base layer in a concavo-convex pattern, and a plurality of irregularly arranged irregularly arranged patterns on the pattern layer so as to protrude higher than the height of the pattern layer. A first optical sheet having columns; And, The protruding end of the column is made of a flat surface, Wherein a diffusion pattern, a hemispherical lens, or a microlens is further formed on the flat surface of the column. 20. The method of claim 19, Wherein the backlight unit further includes at least one of a light guide plate for guiding light emitted from the light source and a diffusion plate for diffusing light emitted from the light source, Wherein the first optical sheet is laminated on the light guide plate or the diffuser plate. 21. The method of claim 20, Wherein the light guide plate or the diffusion plate has a plurality of columns protruding higher than the height of the pattern layer of the backlight unit. 20. The method of claim 19, Further comprising at least one additional optical sheet having a base layer and a pattern layer formed in a concavo-convex pattern on the base layer. 23. The method of claim 22, Wherein the additional optical sheet has a plurality of columns protruding higher than a height of its pattern layer. 23. The method of claim 22, Wherein the plurality of columns are irregularly arranged. 24. The method of claim 23, And the end of the protruded column is made of a flat surface. 26. The method according to claim 19 or 25, Wherein the column has a rounded edge at the flat surface. 27. The method of claim 26, Wherein the edge of the flat surface is a circular arc having a radius R of 0.4 to 15 占 퐉. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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