KR20090119530A - Light guide plate with patterns replacing optical film's functions, and backlight unit and lcd employing the same - Google Patents

Abstract

PURPOSE: A light guide plate for an LCD with a pattern which can replace an optical film function, and a backlight unit and an LCD using the same are provided to use a light guide plate of an integrated optical film function, thereby improving brightness and brightness uniformity without an optical film. CONSTITUTION: In a lower side of a light guide plate(120), a pattern group(150) is formed at the same intervals in parallel. The pattern group is formed with a plurality of parallel prism type patterns(150-1~150-n). Each parallel prism type pattern is formed in parallel with a light source(100). Length of the parallel prism type pattern gradually increases according as the parallel prism type patterns become farther from the light source. The length of the parallel prism type pattern gradually decreases according as the parallel prism type patterns become closer to the light source.

Description

Light guide plate with patterns replacing optical film's functions, and backlight unit and LCD employing the same}

The present invention relates to a light guide plate for a liquid crystal display device, and a backlight unit and a liquid crystal display device employing the same, and more particularly, a light guide plate for a liquid crystal display device having a pattern that can replace the function of an optical film, and a backlight using the same. It relates to a unit and a liquid crystal display device.

A liquid crystal display device adjusts the amount of light transmitted from a back light unit by a liquid crystal panel composed of a plurality of liquid crystal cells arranged in a matrix form and a plurality of TFT switches for switching video signals to be supplied to the liquid crystal cells. This is a display device for displaying a desired image.

1 is a view showing the structure of a backlight unit according to the prior art.

Referring to FIG. 1, a backlight unit is generally formed to surround a lamp 10 that is a light source for generating light and a rear surface of the lamp 10 to condense the light of the lamp 10 in one direction. The light guide plate 12 for converting the light incident from the lamp 10 into the surface light source is disposed on the bottom surface of the light guide plate 12 and the light traveling toward the bottom surface and the side surface of the light guide plate 12 toward the top surface (output surface). A reflector 16 for reflecting, a diffuser sheet 18 for diffusing light emitted to the exit surface side, which is the upper surface of the light guide plate 12, and an agent for adjusting the propagation direction of the light passing through the diffuser sheet 18; And first and second Brightness Enhancement Films (BEFs) 21 and 22.

The light supplied from the lamp 10 is incident on the side surface (incident surface) of the light guide plate 12 and exits to the upper surface (emission surface) side. At this time, the reflector 16 reflects the light emitted to the lower surface of the light guide plate 12. Exit to the exit surface side. The diffusion sheet 18 diffuses the light exiting through the exit surface of the light guide plate 12 to improve the brightness uniformity of the exiting light.

Each of the first BEF 21 and the second BEF 22 is configured to increase the right angle of light in the left and right directions (left and right directions based on the light exit plate of the light guide plate) and up and down directions (up and down directions based on the exit plane of the light guide plate). It consists of a prism film. That is, the first BEF 21 improves the exit angle in the left and right directions of the light passing through the diffusion sheet 18 so that the emitted light is focused in a direction perpendicular to the light guide plate plane on the left and right directions of the exit surface, and the second BEF 22. ) Improves the exit angle in the vertical direction of the light passing through the first BEF 21 so that the emitted light is focused in a direction perpendicular to the light guide plate surface on the vertical direction of the exit surface.

A liquid crystal panel (not shown) is positioned on an upper surface of the backlight unit, and the liquid crystal panel controls the transmittance of light emitted from the backlight unit to implement an image.

In the backlight unit having such a structure, the luminance and uniformity of the light supplied to the liquid crystal panel are very important. That is, the higher the luminance, the lower the power consumption of the liquid crystal display, the improved contrast ratio of the final output image, and the higher the uniformity of the luminance, the higher the image quality of the final output image.

On the other hand, the diffusion sheet 18, the first BEF (21) and the second BEF (22) is a configuration necessary for improving the brightness and brightness uniformity, but the manufacturing cost of the backlight unit is increased by the use of such optical films, assembly There is a problem that the deterioration and the failure rate is increased.

Accordingly, an object of the present invention is to provide a light guide plate for a liquid crystal display device having a pattern which can replace the function of an optical film, and a backlight unit and a liquid crystal display device employing the same.

In the light guide plate according to the present invention for achieving the above object, in the light guide plate of the backlight unit for a liquid crystal display device, at least one pattern group consisting of a plurality of parallel prismatic pattern is formed on the lower surface of the light guide plate, The parallel prismatic patterns each have a length gradually formed in a direction away from the light source, and a length thereof gradually formed in a direction closer to the light source.

Preferably, the prismatic pattern is characterized in that each formed parallel to the light source.

The pattern group may be provided in plural, and the plurality of pattern groups may be formed side by side at equal intervals.

In addition, at least one side of both sides of the pattern group, characterized in that the side pattern group consisting of a plurality of parallel prismatic side pattern is formed in the length toward the both ends of the light guide plate is formed long.

In addition, the plurality of parallel prismatic pattern is characterized in that formed at regular intervals.

The plurality of parallel prismatic patterns may have a predetermined radius of curvature.

In addition, the interior of the inclined both sides of the pattern is characterized in that the 60 ~ 120 °.

In addition, the height of the pattern is characterized in that 1 ~ 25μm.

The pattern may be formed such that the inclination angles of both surfaces inclined with respect to the lower surface of the light guide plate are different from each other.

In addition, the upper surface of the light guide plate is characterized in that a plurality of parallel prismatic pattern formed in the vertical direction to the light source.

In addition, the inner angle formed by the inclined both sides of the pattern formed on the upper surface of the light guide plate is characterized in that the 80 ~ 140 °.

In addition, the height of the pattern formed on the upper surface of the light guide plate is characterized in that 5 ~ 50μm.

In addition, each of the patterns is characterized in that the projection is formed from the light guide plate surface.

In addition, each said pattern is characterized by being recessed from the light guide plate surface.

On the other hand, the backlight unit according to the invention is characterized in that it comprises a light guide plate having the above configuration, a light source for supplying light to the light guide plate, and a reflecting plate disposed on the surface on which the pattern of the light guide plate is formed.

On the other hand, the liquid crystal display device according to the invention is characterized in that it comprises a backlight unit having the above configuration.

According to the present invention, in manufacturing the backlight unit, by using the light guide plate in which the function of the optical film is integrated, it is possible to improve the luminance and improve the luminance uniformity without using the optical film.

In addition, in manufacturing the backlight unit, by not using the optical film, the manufacturing cost of the backlight unit is reduced, there is an effect that ensures ease of assembly during manufacturing and lower the defective rate.

Hereinafter, with reference to the drawings will be described the present invention in more detail. It should be noted that the same elements in the figures are represented by the same numerals wherever possible. In addition, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

FIG. 2A illustrates a shape of a pattern formed on a bottom surface of a light guide plate according to an exemplary embodiment of the present invention. Referring to FIG. 2A, a pattern group 150 including a plurality of parallel prismatic patterns 150-1,..., 150-n is formed side by side at equal intervals on a lower surface of the light guide plate 120 according to the present invention. It can be confirmed.

Here, each prismatic pattern 150-1,..., 150-n is formed to be parallel to the light source 100, and a plurality of prismatic patterns 150-1 constituting each pattern group 150. ...., 150-n are each formed gradually longer in length as the distance from the light source 100 increases, and gradually shorter in length as the distance from the light source 100 approaches. .

Meanwhile, in practicing the present invention, the plurality of prismatic patterns 150-1,..., 150-n constituting each pattern group 150 may be formed in parallel at regular intervals.

As shown in FIG. 2A, as the distance from the light source 100 increases, the lengths of the patterns 150-1,..., 150-n are gradually increased, thereby guiding the light guide plate even at a position far from the light source 100. By condensing the entire light incident on 120 vertically, as the distance from the light source 100 gets closer, the length of the patterns 150-1, .., 150-n is gradually shortened, The light incident on the light guide plate 120 may be vertically collected at a position close to the light source 100, and thus uniform light may be obtained from the front surface of the light guide plate 120.

2B is a view showing the shape of a pattern formed on the bottom surface of the light guide plate according to another embodiment of the present invention. For reference, the light guide plate 120 of FIG. 2B has a configuration for preventing light loss occurring at the corner portion P of the light guide plate 120 of FIG. 2A.

2B, a plurality of pattern groups 150 including a plurality of parallel prismatic patterns 150-1,..., 150-n are arranged side by side at equal intervals on a lower surface of the light guide plate 120 according to the present invention. At the same time, both side surfaces of the plurality of pattern groups 150 have a side pattern formed of a plurality of side patterns 170-1,..., 170-n formed in a lengthwise direction toward both ends of the light guide plate 120. It can be seen that the unit 170 is formed.

That is, when the light guide plate 120 of FIG. 2B is closer to the light source 100, which is formed at the corner portion P of the light guide plate 120, the side pattern 170-1, which is formed to have a longer length, is formed. By 170-n, it is possible to improve the problem of lowering the luminance at the edge portion P of the light guide plate 120 by preventing light loss occurring at the edge portion P of the light guide plate 120. do.

On the other hand, in the practice of the present invention, the spacing between the plurality of parallel prismatic patterns 150-1,..., 150-n and the patterns of the side patterns 170-1,. It is preferable that the length of is not more than twice, and the inclined both sides in each pattern of the prismatic pattern 150-1, .., 150-n and the side pattern 170-1, .., 170-n are formed. It is preferable that the inside angle is 60 to 120 °, and the height of each pattern in the prismatic patterns 150-1, .., 150-n and the side patterns 170-1, .., 170-n is 1-25 μm. Would be preferred.

On the other hand, the amount of condensed light and the position where the light is condensed are different according to the inclined sides of the inclined sides. When the interior angle is less than 60 °, the condensation amount decreases and the viewing angle range required by the backlight is exceeded. A range between 60 and 120 ° is desirable because it falls outside the viewing angle range required for reduction and backlighting.

In addition, the finer the pattern size, the better the appearance quality. The smaller the size, the better. However, when the size is less than 1μm, the actual production is difficult due to mold problems and product manufacturing problems. The production is advantageous, but the appearance of the pattern appears.

In addition, the pattern interval is characterized in that the smaller the pattern interval is improved the amount of luminance condensing, and when the pattern interval is formed at an interval of more than twice the length of the prism mountain formed, the luminance concentration is more than 50% compared to the continuous position Will decrease.

FIG. 2C is a diagram illustrating a shape of a pattern formed on a bottom surface of a light guide plate according to another embodiment of the present invention. FIG. Referring to FIG. 2C, pattern groups 160 made of prismatic patterns 160-1,. It can be confirmed that it is formed.

Here, the plurality of prismatic patterns 160-1,..., 160-n constituting each of the pattern groups 160 are formed to gradually increase in length as the distance from the light source 100 increases, respectively. As the distance from the light source 100 approaches, the length thereof is gradually shortened.

According to the linear prismatic patterns 150-1,..., 150-n in FIG. 2A, the upper and lower viewing angles can be efficiently focused, but the viewing angles of the left and right tend to be slightly wider, as shown in FIG. 2C. According to the prismatic patterns 160-1,..., 160-n having a narrow viewing angle, the left and right viewing angles are narrowed, thereby improving luminance and improving viewing angle.

FIG. 3 shows applicable lower surface shapes in cross section A-A 'of the light guide plate in FIGS. 2A, 2B, and 2C. The pattern formed on the light guide plate 120 according to the present invention may be recessed (engraved) from the lower surface of the light guide plate 120 as in (a), (b), (c), (d), and (e) ), (f), (g), (h) may be formed as a protrusion (embossed).

In addition, in the practice of the present invention, as shown in Fig. 3 (c), (g) by forming the corner angle of the prism pattern formed in the light guide plate 120 according to the present invention to improve the appearance quality of the light guide plate 120 You might be able to improve it.

In addition, in the practice of the present invention, as shown in (d), (h) of FIG. In the case of the wedge-shaped light guide plate, it may be possible to enable the optimum light output according to the shape of the wedge.

In addition, in the embodiment of the present invention, as shown in FIGS. 3B and 3F, the pattern 150 is continuously formed on the bottom surface of the light guide plate 120 without a gap between the patterns 150-1,..., 150-n. -1, .., 150-n).

4 is a diagram illustrating a shape of an upper surface pattern formed on an upper surface of a light guide plate according to still another embodiment of the present invention. Referring to FIG. 4, it can be seen that a plurality of parallel upper surface patterns 190-1,..., 190-m are formed side by side at equal intervals on the upper surface of the light guide plate 120 according to the present invention.

Here, each of the upper surface patterns 190-1,..., 190-n is formed in a direction perpendicular to the light source 100, and the length of the upper surface patterns 190-1,. The plurality of parallel upper surface patterns 190-1,..., 190-m formed on the upper surface of the light guide plate 120 in FIG. 4 is a plurality of parallel prism types formed on the lower surface of the light guide plate 120 in FIG. 2A. By being formed in a direction perpendicular to the patterns 150-1,..., 150-n, the light emitted by the prism pattern 150-1,. As a result, the light is condensed.

On the other hand, in the practice of the present invention, the interior angle formed by the inclined both sides in each pattern of the upper surface patterns 190-1, .., 190-m formed on the upper surface of the light guide plate 120 in FIG. It is preferable that the height of each top pattern 190-1,..., 190-m be 5 to 50 μm.

Specifically, the amount of the left and right viewing angles varies depending on the cabinet, because when it is 80 ° or less, or 140 ° or more, light cannot be collected from left and right, and each top pattern 190-1, .., 190 If the height of -m) is over 50μm, it is easy to manufacture light guide plate but there is a possibility that moiré occurs on LCD panel.If it is less than 5μm, the appearance quality is increased but mass production is difficult due to current production method. .

FIG. 5 is a diagram showing applicable top shapes in cross section BB ′ of the light guide plate in FIG. 4. The pattern formed on the light guide plate 120 according to the present invention may be recessed (engraved) from the upper surface of the light guide plate 120 as in (a), (b), (c), (d), (e) As shown in (f), it may be protruding (embossed).

In addition, in the practice of the present invention, the upper surface pattern 190-1, which is formed on the upper surface of the light guide plate 120 according to the present invention, as shown in (c), (d), (e), (f) of FIG. It is also possible to improve the appearance quality of the light guide plate 120 by forming a corner angle of .190-m), and as shown in (a) the upper portion of the upper surface pattern (190-1, .., 190-m) It may be formed to be flat, and as shown in (b) it may be to form a vertex on the top pattern.

In addition, in the practice of the present invention, the light guide plate 120 without a gap between the upper surface patterns 190-1, .., 190-m, as shown in (a), (b), (d), and (f) of FIG. The upper surface pattern 190-1,..., 190-m may be continuously formed on the upper surface of), and may be formed at regular intervals as in (c) and (e).

In addition, in the practice of the present invention, as shown in (e) and (f) of FIG. 5, when the cross-section of the upper surface pattern has an arc shape like a semi-cylindrical shape, the luminance is slightly reduced, but the effect of improving the appearance quality and reducing manufacturing defects. Would be acceptable.

While the above has been shown and described with respect to preferred embodiments and applications of the present invention, the present invention is not limited to the specific embodiments and applications described above, without departing from the gist of the invention claimed in the claims Various modifications may be made by those skilled in the art to which the invention pertains, and such modifications should not be understood individually from the technical spirit or the prospect of the present invention.

1 is a view showing the structure of a backlight unit according to the prior art,

2A is a view showing the shape of a pattern formed on a bottom surface of a light guide plate according to an embodiment of the present invention;

2B is a view showing a shape of a pattern formed on a bottom surface of a light guide plate according to another embodiment of the present invention;

2C is a view showing a shape of a pattern formed on a bottom surface of a light guide plate according to another embodiment of the present invention;

3 shows applicable bottom shapes in cross section A-A 'of the light guide plate in FIGS. 2A, 2B, and 2C;

4 is a view showing the shape of a pattern formed on the upper surface of the light guide plate according to another embodiment of the present invention, and

FIG. 5 is a diagram showing applicable top shapes in cross section BB ′ of the light guide plate in FIG. 4.

Claims (16)

In the light guide plate of the backlight unit for a liquid crystal display device, At least one pattern group including a plurality of parallel prismatic patterns is formed on a lower surface of the light guide plate, The plurality of parallel prismatic patterns are each formed in a progressively long length in a direction away from the light source, and a length thereof is gradually shortened in a direction approaching from the light source. The method of claim 1, The prismatic pattern is formed to be parallel to the light source, respectively. The method of claim 1, The pattern group is to be plural, The plurality of pattern groups are formed side by side at equal intervals. The method of claim 1, At least one side of both sides of the pattern group, The light guide plate is formed with a side pattern group consisting of a plurality of parallel prismatic side pattern is formed in the longitudinal direction toward both ends of the light guide plate. The method of claim 1, The plurality of parallel prismatic pattern is a light guide plate formed at regular intervals. The method of claim 5, Wherein the plurality of parallel prismatic patterns has a predetermined radius of curvature. The method of claim 1, The light guide plate of which the angle formed by the inclined both sides of the pattern is 60 ~ 120 °. The method of claim 1, The light guide plate of which the height of the pattern is 1 ~ 25μm. The method of claim 1, The pattern is a light guide plate formed so that the inclination angles of both surfaces inclined with respect to the lower surface of the light guide plate are different from each other. The method of claim 2, The light guide plate of the light guide plate is formed with a plurality of parallel prism-type patterns formed in a direction perpendicular to the light source. The method of claim 10, The interior of the light guide plate formed by the inclined both sides of the pattern formed on the upper surface of the light guide plate is 80 ~ 140 °. The method of claim 11, The light guide plate of the pattern formed on the upper surface of the light guide plate is 5 ~ 50μm. The method according to claim 1 or 11, wherein Each said pattern is a light guide plate protruding from the light guide plate surface. The method according to claim 1 or 11, wherein Each said pattern is recessed from the light guide plate surface. A light guide plate having a configuration as described in claim 1; A light source for supplying light to the light guide plate; And Reflector plate disposed on the surface of the light guide plate is formed Backlight unit comprising a. A liquid crystal display device comprising a backlight unit having the configuration as described in claim 15.

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