KR20080070902A - Light guide panel for lcd comprising stripe prism of irregular shape and cross prism - Google Patents

Abstract

A light guide panel for an LCD device having main and cross prisms of irregular shapes is provided to suppress an interference pattern and a Moire phenomenon by irregularly forming contours of a stripe pattern or a dot pattern. A light guide panel for an LCD(Liquid Crystal Display) device includes a side surface(401), a front surface(403), and a rear surface(405). The light is emitted from the front surface and reflected on the rear surface. Plural irregular random stripe patterns(410), whose widths increase more and more away from the side surface of the light guide panel, are arranged. A main prism(412) is formed to be normal to an incident direction of the light into the random stripe pattern. A cross prism(422) is formed outside the random stripe pattern.

Description

Light guide panel for LCD comprising stripe prism of irregular shape and cross prism

1 is an exploded perspective view showing a backlight unit of a conventional liquid crystal display device;

2A and 2B are enlarged cross-sectional views of a light guide plate for explaining a process of light generated from a light source in a light guide plate;

3 is a rear perspective view showing a schematic structure of a conventional light guide plate;

4 is a rear perspective view showing a schematic structure of a light guide plate having a random stripe pattern according to an embodiment of the present invention;

5 is a plan view illustrating a rear surface of the light guide plate according to the embodiment of the present invention divided into a pattern region;

6 is a plan view illustrating a random reference line setting method of a main prism for forming a random stripe pattern according to the present invention;

7 is a plan view illustrating a state in which a main prism is disposed based on a random reference line set in FIG. 6;

8 is a plan view showing a rear surface of a light guide plate having a random dot pattern according to the present invention;

9 is a plan view illustrating an embodiment of various types of random dot patterns;

10 and 11 are cross-sectional views of a light guide plate for a liquid crystal display backlight unit according to an exemplary embodiment of the present invention;

12 is an enlarged cross-sectional view showing the vertex angle of the main prism of the light guide plate for a liquid crystal display device backlight unit according to an embodiment of the present invention.

FIG. 13 is an enlarged cross-sectional view illustrating a shape of a main prism of a light guide plate for a liquid crystal display device backlight unit according to an exemplary embodiment of the present invention; FIG.

14 is a perspective view illustrating a light guide plate having a front prism as another embodiment of the present invention;

15 to 17 are perspective views illustrating various embodiments of cross-sectional shapes of the front prisms.

Explanation of symbols on the main parts of the drawings

10: backlight unit

100: panel # 110: light guide plate

115: reflector # 120: diffusion sheet

125: prism sheet # 130: protective sheet

400: Light guide plate # 401: Side

403: Front 405: Back

406: pattern area 410: random stripe pattern

412: main prism 420: spacer area

422: cross prism 430: random dot pattern

CL: Centerline RL: Random Reference Line

P1, P2, P3, P4, P5, P6, P7, P8, P9, P10: Reference Point

R1, R2, R3, R4, R5, R6, R7, R8, R9, R10: Random point

The present invention relates to a light guide plate for a liquid crystal display device including an irregular outline main prism and a cross prism. It is to improve the problems such as.

In general, a liquid crystal display device refers to a device in which a liquid crystal, which is a liquid and a solid intermediate material, is injected between two glass substrates formed of electrodes to apply a electric field to display a number or an image.

Since the liquid crystal display device is not a light emitting device, the liquid crystal display device has a back light unit as a light source for generating light, and the light generated from the backlight unit is used in a panel unit where liquid crystals are constantly arranged. Images are displayed while adjusting the amount of light transmitted.

1 is an exploded perspective view illustrating a backlight unit of a conventional liquid crystal display device.

However, the backlight unit 10 of the liquid crystal display device has a direct light source under which the light source is located directly below the panel 100 of the liquid crystal display device according to the position of the light source that emits light, and a light source on the side surface of the liquid crystal display panel 100. It may be classified into an edge type located, and may be subdivided into a wedge type and a flat type according to the shape of the light guide plate, and FIG. 1 shows a wedge type.

As shown in FIG. 1, a conventional LCD backlight unit includes a light source 105, a light guide plate 110, a reflector plate 115, a diffusion sheet 120, and a prism sheet 125.

Although the light source 105 has various kinds of light sources 105 that can be used as the first light emitting part in the liquid crystal display device, in general, the light source used in the liquid crystal display device has a low power consumption and emits very bright white light. (Cold Cathode Fluorescence Lamp) is used.

The light guide plate 110 is formed on the lower side of the LCD panel 100 and on one side of the light source 105, and converts spot light generated from the light source 105 into plane light to convert the light to the front surface. It serves to project.

A reflector plate 115 is formed on the rear surface of the light guide plate 110 and reflects light emitted from the light source 105 toward the front LCD panel 100.

A diffuser plate 115 is formed on the upper surface of the light guide plate 110 and serves to uniformize the light emitted through the light source 105.

The prism sheet 125 is used to increase brightness by refracting and condensing light that diffuses in both horizontal and vertical directions while passing through the diffusion sheet 120, thereby rapidly decreasing brightness.

The protector sheet 130 is located on the top of the prism sheet 125 to prevent scratches of the prism sheet 125, and the moire phenomenon generated when using the prism sheet 125 formed in two layers in the vertical and horizontal directions. Used to prevent effects.

And, although not shown in Figure 1, the conventional backlight unit 10 is a frame (mold frame, which serves as a case for fixing each component constituting the backlight unit 10 to form a backlight unit 10 as an integral part, It further includes a cover (back cover, lamp cover) to protect the housing and the backlight unit 10 and to serve as strength maintenance and support.

2A and 2B are enlarged cross-sectional views of a light guide plate for explaining a process of light generated in the light source 105 in the light guide plate 110.

As shown in Fig. 2A, the light source 105 is usually located at the edge of the backlight unit 10 (in the case of LCD TV, it may be located directly behind the panel). As a result, the light is not uniformly transmitted over the entire surface and the edge tends to be brighter. To prevent this, the light guide plate 110 is used. The material of the light guide plate is usually a transparent acrylic resin, which is characterized by high strength and low cracking or deformation, and is light and has high visible light transmittance.

That is, the light guide plate 110 serves to cause the light source 105 to be uniformly projected on the front surface of the light guide plate 110. In fact, the light guide plate 110 may be disassembled by placing the light source on the side of the light guide plate to generate light. It can be seen that the surface of 110 is not uniformly bright but light is concentrated at both ends, because the light guide plate 110 guides the light of the light source 105 to the opposite side.

Therefore, as shown in FIG. 2B, in order to cause diffuse reflection on the rear surface of the light guide plate 110 so that the entire light guide plate 110 emits light uniformly, in particular, the distance from the light source 105 is considered. Prominence and depression (113) surface having a predetermined shape is designed. As a result of the pattern processing by forming the irregularities (113), flat light having a relatively high luminance and uniformity in the entire panel of the liquid crystal display device is formed. Is obtained.

However, when the LCD is manufactured using only the above method, the portion where the unevenness 113 is actually formed in the panel looks bright, and the part where the unevenness 113 is not formed appears dark, so the spot on the panel is spotted. The visible phenomenon occurs and the visibility is reduced. In particular, as the size of the panel has recently increased in size, an absolute amount of light reaching the light source 105 may be insufficient and thus may appear dark.

In addition, the diffusion sheet 120 and the prism sheet 125 is used to increase the uniformity of light, such a diffusion sheet or prism sheet has a problem of increasing the manufacturing cost of the backlight unit.

Therefore, without using a separate diffusion sheet 120 or prism sheet 125, a plurality of prisms are arranged on the rear surface to obtain planar light having excellent visibility and high brightness and uniformity on the front surface of the panel of the liquid crystal display device. Light guide plates of the same type have been proposed.

3 is a rear perspective view showing a schematic structure of a conventional light guide plate.

As shown, the light source 306 is disposed on one side of the light guide plate 300. A side from which light is directly incident from the light source 306 is defined as a side 301, a surface from which light is emitted is defined as a front side 303, and a side of half-sided light is defined as a rear side 305. do.

A plurality of prisms are disposed on the rear surface 305 to refract and reflect light to the front surface. A main prism 322 is disposed in the stripe pattern 320, and a cross prism 340 perpendicular to the main prism 322. ) Is placed. The set of main prisms 322 forms one stripe pattern 320.

The main prism 322 is formed in the longitudinal direction of the prism parallel to the longitudinal direction of the light source 306, the cross-prism 340 is formed in the longitudinal direction of the prism perpendicular to the longitudinal direction of the light source 306 It is.

In order to uniformly control the amount of light emitted to the front surface, the length of the main prism 322 is formed in proportion to the distance to the light source. That is, the main prism 322 is formed at a portion close to the light source 306, and the length increases as the distance from the light source is shortened.

As such, the main prism 322 reflects and diffracts the light incident from the side to the front, and controls the uniformity, and the cross prism 340 collects the horizontality of the incident light.

The cross prism 340 is formed at a portion where the main prism 322 is not formed. As shown in FIG. 3, when the boundary surface of the main prism 322 and the cross prism 340 becomes a straight line, interference of light occurs, and a visibility pattern occurs such that an interference fringe appears.

In the conventional light guide plate, as shown in FIG. 3, the stripe pattern is symmetrical left and right, and the outline of the stripe pattern has a uniform straight or curved shape.

Such an arrangement has a problem of generating an interference fringe (moire) due to regular overlapping or miss align, so that the present invention provides a random stripe pattern by unevenly adjusting the outline of the stripe pattern 510. By forming the 410 of Figure 4 is to solve the above problems.

An object of the present invention is to provide a light guide plate that can exclude the interference effect between the cross prism and the main prism.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a light guide plate for a liquid crystal display device backlight unit having high luminance and excellent light uniformity and visibility in the entire panel of the liquid crystal display device.

Technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a light guide plate for a liquid crystal display device including a side on which light is incident, a front surface connected to the side surface, and a rear surface reflecting light. ,

It includes a plurality of irregularly shaped random stripe pattern that increases in width as the distance away from the light incident side, the main prism formed in a direction perpendicular to the direction in which light is incident inside the random stripe pattern, A light guide plate for a liquid crystal display device including a cross prism outside the random stripe pattern is provided.

According to another aspect of the present invention, there is provided a backlight unit for a liquid crystal display device including a light source and a light guide plate according to embodiments of the present invention.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, only the embodiments are to make the disclosure of the present invention complete, and the general knowledge in the technical field to which the present invention belongs. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

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

4 is a rear perspective view illustrating a schematic structure of a light guide plate having a random stripe pattern according to an exemplary embodiment of the present invention.

The present invention provides a liquid crystal display including a side surface 401 on which light is incident, a front surface 403 connected to the side surface 401, and a rear surface 405 reflecting light. In the light guide plate 400, a plurality of irregularly-shaped random stripe patterns 410 having the width W increase as the distance from the side where light is incident on the rear surface 405 is the same. Although the pattern is formed, only the center stripe pattern indicated by a dot is indicated by dots in order to clearly display the area of the stripe pattern), and the direction in which light is incident inside the random stripe pattern 410. It provides a light guide plate for a liquid crystal display device including a main prism 412 formed in a vertical direction and a cross prism 422 outside the random stripe pattern.

The main prism 412 is a set of prisms having different lengths, and irregularly formed the outline of the stripe pattern 410 in order to prevent interference of light at the interface. Hereinafter, for convenience of description, the stripe pattern having irregular outlines is referred to as a random stripe pattern 410.

Although the random stripe pattern 410 is irregular in its outline, it is not preferable to overlap the different f random stripe patterns 410. If there is an overlapping portion not only adversely affects the optical properties of the light guide plate 400, but also may cause the appearance of the pattern drift phenomenon.

Accordingly, the random stripe pattern 410 has a finite irregular outline within the pattern pitch PP described later with reference to FIG. 5.

The random stripe pattern 410 also must adhere to providing uniform planar light, which is the original function of the stripe pattern. Accordingly, the width W of the random stripe pattern is set to increase as the distance from the light source increases. Cross prisms are disposed in spacer areas other than the stripe pattern.

Hereinafter, a method of forming a random stripe pattern in one pattern region will be described with reference to the drawings.

5 to 8 illustrate embodiments of the stripe pattern, and FIGS. 9 and 10 describe embodiments of the random dot pattern.

FIG. 5 is a plan view illustrating a rear surface of a light guide plate according to an exemplary embodiment of the present invention divided into a pattern region having a predetermined pattern pitch PP. The back surface 405 of the light guide plate has a plurality of patterns having a predetermined pattern pitch PP. Is divided into a pattern area 406 (rectangle indicated by a solid line). One random stripe pattern 410 is formed in one pattern region 406. The random stripe pattern 410 is composed of a set of main prisms 412 of different lengths.

An area excluding the region where the random stripe pattern 410 is formed in the pattern region 406 is called a spacer region 420 (hatched portion), and a cross prism 422 (not shown) is disposed in the spacer region. By the way, the cross prism is arranged after the random stripe pattern 410 is completely disposed, and is not shown in FIG. 5.

6 is a plan view illustrating a random reference line setting method of a cross prism for forming a random pattern according to the present invention.

In order to form the random stripe pattern 410 of FIG. 4, first, a random reference line RL which is an arrangement reference of the cross prisms must be set.

As shown, first, reference points P1, P2, P3, P4, P5, of a predetermined number (10 reference points are set for convenience of description) in the center line CL of the pattern region 406. P6, P7, P8, P9, and P10) are set.

The set reference points P1, P2, P3, P4, P5, P6, P7, P8, P9, and P10 are scattered above and below the reference line below a random ratio.

The random ratio means a range that can deviate from the reference point, and the meaning of the maximum random ratio means an arbitrary value of 10 or less, for example, when the maximum random ratio is 10. For convenience, if the displacement above the baseline is indicated by + sign and the displacement below the baseline is −, the random ratio of the illustrated embodiment is shown in Table 1.

It is just one example of Table 1, and may select a range deviating from the baseline by selecting at random from the values below the random ratio.

The points shifted by the random ratio from the reference point are called random points (R1, R2, R3, R4, R5, R6, R7, R8, R9, R10) .

A random reference line RL sequentially passes through the random points R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 from the start point S to the end point E of the pattern. The random reference line RL may form a random reference line RL by sequentially connecting the random points in a straight line as shown, or set a gentle curve passing all the random points as a random reference line.

The random ratio, which is the maximum value deviating from the center line CL, may be arbitrarily selected by the designer. However, a caution in setting the random ratio is that no cross prisms should be arranged outside the pattern. To this end, the random ratio is preferably equal to or less than half the difference between the pattern pitch, which is the width of the pattern region 510, and the length of the longest cross prism.

For example, if the pattern pitch is 100 µm and the length of the longest cross prism is 80 µm, the maximum value of the random ratio should be set to 10 µm or less. The maximum value of the random ratio is called the maximum random ratio, and the maximum random ratio means a predetermined value within a range below that value.

Another method of setting the maximum random ratio is a method of applying the ratio of the width of the spacer area to the percentage of the width of the spacer area.

For example, if the pattern pitch is 100 m and the length of the main prism is 60 m, the width of the spacer region is 40 m. If the maximum random ratio is set to 50%, it has a random ratio within the range of 20 μm, which is 50% of 40 μm. In the case of applying this method, the wider the spacer area, the greater the distance that the main prism can move irregularly. Therefore, the moving width of the main prism becomes wider in the portion closer to the light source, and the moving width of the main prism becomes narrower as it moves away from the light source.

FIG. 7 is a plan view illustrating a state in which a cross prism is disposed based on the random reference line set in FIG. 6.

As shown, the main prisms 412 are arranged so that the center of each main prism 412 coincides with the random reference line RL, and the spacer region 420 is a region other than the region where the main prisms 412 are formed. The cross prism 422 is disposed. The longitudinal direction of the cross prism 422 is most preferably at an angle of 90 ° to the longitudinal direction of the main prism 412, but is allowed in the range of 60 ° to 120 ° considering the error range occurring in design or manufacture. .

When the main prisms 412 are arranged based on the random reference line RL, a random stripe pattern 410 having an irregular boundary line with the cross prisms 422 is formed. Accordingly, interference fringes and moiré phenomena generated due to the regularity of the main prisms 412 and the cross prisms 422 may be prevented and the pattern hiding power may be improved.

FIG. 8 is a plan view illustrating a rear surface of a light guide plate on which a random dot pattern is formed, and FIG. 9 is a plan view illustrating an embodiment of various types of random dot patterns.

The pattern formed by the set of cross prisms may have a form of a continuous stripe pattern as described above, but may have a form in which dot patterns formed in a predetermined region are repeated as shown.

In the case of the stripe pattern, the width of the dot pattern 430 becomes wider as it moves away from the light source. As the dot pattern 430 moves away from the light source 105, a larger number is arranged to control the amount of light.

The random dope pattern 430 according to the present invention is formed by forming the random reference line RL in the same manner as the method of forming the random stripe pattern and arranging the center of the main prism 412 therein.

As shown in FIG. 9, the random dot pattern may have one of a circle (a), an ellipse (b), a rhombus (c), and a rectangle (d), or a combination thereof.

10 and 11 are partial cross-sectional views illustrating a light guide plate for a liquid crystal display backlight unit according to an exemplary embodiment of the present invention.

The main prism 412 and the cross prism 422 are formed to have different heights. This is for manufacturing convenience, as shown in FIG. 10, the crossprism 442 may be formed at a height lower than that of the main prism 412, and vice versa. Cross prisms 422 may be formed at the height.

Hereinafter, the light guide plate according to the embodiment of the present invention will be described with reference to specific embodiments that have better properties when measuring brightness, uniformity and visibility of light. Details not described herein are omitted because they can be sufficiently inferred by those skilled in the art.

Referring to the embodiments performed to demonstrate the effect of the configuration of the present invention.

< Example  1>

The size of the stripe pattern was changed as in the present invention. Width (W) x length (L) x thickness (T); Pattern pitch 430㎛ at the bottom of wedge light guide plate manufactured to be 288.8 × 217.7 × 2.4 (start) × 0.8 (end) mm, maximum random rate 0.5% (where maximum random rate is 0.5% of the width of spacer area) In the following, the percentage of the random ratio means the ratio to the width of the spacer region.) A random stripe pattern is formed, and inside the pattern 을 a main prism having a height of 14.9 µm, a pitch of 25 µm, and an internal angle of 80 ° Formed. The upper surface of the light guide plate was made into a mirror state. Cross prisms having a height of 9.6 mu m, a pitch of 25 mu m, and an inner angle of 105 degrees were formed in regions other than the stripe pattern in a direction other than the main prism under the light guide plate. The upper surface of the light guide plate was made into a mirror state.

< Example  2 to Example  8>

The same procedure as in Example 1 was repeated except that a random stripe pattern having a maximum random ratio of 1.5%, 2.5%, 3.5%, 5%, 15%, 30%, and 50% was shown. It was.

Table 3 shows the results of measuring brightness, uniformity and visibility according to the experimental conditions of the examples.

Examples 1 to 6 showed similar results in terms of brightness and uniformity among optical characteristics. However, in Examples 1 and 2, interference fringes were generated between the main prism and the cross prism, resulting in an unsatisfactory appearance, and in Examples 7 and 8, the luminance was decreased. This is because the optical path is changed as the random ratio is increased and the vertical luminance component is lowered.

In the case of Example 6, the optical properties and the moire were good, but the contrast was caused by the left and right deviation of the stripe pattern. This phenomenon is more pronounced as the random ratio increases. On the contrary, Examples 3 to 5 showed the best results in optical properties and appearance, and uniform plane light was obtained. In view of this, it is determined that the maximum random ratio is preferably between 1.5% and 15% of the width of the spacer region, and more preferably between 2 and 10%.

12 is an enlarged cross-sectional view illustrating a vertex angle of a cross prism of a light guide plate for a liquid crystal display backlight unit according to an exemplary embodiment of the present invention. The angles of the vertex angle from the left side are 80 °, 90 °, 100 °, 110 °, 120 °, 130 °, and 140 °, and the pitch of each prism is 25 µm.

FIG. 13 is an enlarged cross-sectional view illustrating the shape of a main prism of a light guide plate for a liquid crystal display backlight unit according to an exemplary embodiment of the present invention. The left side shows the case where no curvature radius is given, the center side shows the positive curvature radius, and the right side shows the negative curvature radius.

Referring to the embodiments performed to demonstrate the effect of the configuration of the present invention.

< Example  9-1>

Width (W) x length (L) x thickness (T); A stripe pattern with a pattern pitch of 430 μm is formed on the bottom of the wedge light guide plate manufactured to be 288.8 × 217.7 × 2.4 (start) × 0.8 (end) mm, and inside the pattern 높이 14.25㎛, pitch 25㎛, inside angle 82.5 ° Phosphorus main prism was formed. Further, cross prisms having a pitch of 25 占 퐉, a height of 10.49 占 퐉, and an angle of # 100 ° were formed in regions other than the stripe pattern in a direction other than the main prism under the light guide plate. The front surface of the light guide plate was made into a mirror state.

< Example  9-2 to 9-8>

It carried out similarly to Example 9-1 except having changed the cross prism angle to 110-170 degree by 10 degree unit. Change factors for Examples 9-1 to 9-8 are briefly shown in Table 4.

< Comparative example  1>

Width (W) x length (L) x thickness (T); A stripe pattern with a pattern pitch of 430 μm is formed on the bottom of the wedge light guide plate manufactured to be 288.8 × 217.7 × 2.4 (start) × 0.8 (end) mm, and inside the pattern 높이 14.25㎛, pitch 25㎛, inside angle 82.5 ° Phosphorus main prism was formed.

< Example  10-1>

Width (W) x length (L) x thickness (T); A stripe pattern with a pattern pitch of 430 μm is formed on the bottom of the wedge light guide plate manufactured to be 288.8 × 217.7 × 2.4 (start) × 0.8 (end) mm, and inside the pattern 높이 14.25㎛, pitch 25㎛, inside angle 82.5 ° Phosphorus main prism was formed. At this time, the radius of curvature of the prism side was set to (+) 0.1R. Cross prisms each having a width of 8.75 µm and an angle of 110 degrees were formed. The front surface of the light guide plate was made into a mirror state.

< Example  10-2 to 10-8>

Except having changed the R value which is the radius of curvature of a prism edge by 0.1 from (+) 0.4 to (-) 0.4, it carried out similarly to Example 10-1. Change factors for Examples 10-1 to 10-8 are briefly shown in Table 5.

< Comparative example  2>

Width (W) x length (L) x thickness (T); A stripe pattern with a pattern pitch of 430 μm is formed on the bottom of the wedge light guide plate manufactured to be 288.8 × 217.7 × 2.4 (start) × 0.8 (end) mm, and inside the pattern 높이 14.25㎛, pitch 25㎛, inside angle 82.5 ° Phosphorus main prism was formed. Further, cross prisms having a pitch of 25 占 퐉, a height of 8.75 占 퐉, and an angle of # 110 ° were formed in regions other than the stripe pattern in a direction other than the main prism under the light guide plate. The front surface of the light guide plate was made into a mirror state.

Table 6 shows luminance measurement results of Examples 9-1 to 9-8 and Comparative Example 1. FIG. Referring to Table 6 above, the embodiments generally show a higher central luminance value than the comparative example, but in the case of Example 9-2, the luminance is the highest, and the ratio is superior to Examples 9-1 to 9-6. It can be seen that the crossin prism cabinet is between 100 and 160 °.

Table 7 shows luminance measurement results for Examples 10-1 to 10-8 and Comparative Example 2. Referring to Table 7 above, Example 10-3 shows the highest luminance, and Examples 10-1 and 10-5 to 10-8 show a sharp decrease in the center luminance compared to Comparative Example 2.

Although the embodiments having the variation R of the main prism as a whole exhibit a higher central luminance value than the comparative example, it can be seen that the case where the ratio is superior is an R value between Examples 10-2 to 10-4.

In terms of the ratio of the radius of curvature to the pitch of the main prism, it is preferable that the ratio of the pitch: curvature radius to the pitch of the main prism is groove or reverse groove type having a range of 1: 1 to 1:30.

As described above, in the case of using the light guide plate according to the present invention, a prism sheet, which is generally used in a backlight unit for a conventional liquid crystal display, may have the same effect as using these. That is, in the case of using the light guide plate according to the embodiments of the present invention, one or two optical sheets among sheets applied to the conventional backlight unit may be reduced.

14 is a perspective view illustrating a light guide plate having a front prism as another embodiment of the present invention.

In this embodiment, the front surface 403 has a predetermined cross-sectional shape, and front prisms 440 are formed to uniformly rotate, refract, and diffuse light emitted through the light guide plate 400. As shown in FIG. 4, the rear surface 405 has a random stripe pattern 410 and a cross-prism 412 formed therein.

The front prisms 440 are formed over the entire front surface 403 without being spaced apart from each other, and the front prisms 440 have a direction in which light is emitted from the light source 105 in the longitudinal direction of each front prism 440. It is formed to coincide with.

In FIG. 14, the vertical cross-sections of the front prisms 440 are triangular in shape, but the shape of the front prisms 440 is not limited thereto. In particular, when the front prism 440 has a triangular cross section, the vertex angle is preferably in the range of 70 ° to 100 °.

15 to 17 are perspective views illustrating various embodiments of cross-sectional shapes of the front prisms 440.

As shown in FIG. 15, the front prisms 440 may be formed to have a predetermined spacing plane.

The reason why the front prisms 440 are formed at a predetermined distance d without densely arranging them is to improve and improve light uniformity and visibility.

That is, the light emitted from the light guide plate 300 is diffracted, refracted, and diffused in a direction inclined to the panel (not shown) of the liquid crystal display device facing the light guide plate by the front prisms 440, but the front prisms By providing the separation distance (d) between the 440, the light through the plane (meaning the space between the prism in the front) caused by the separation distance (d) panel (not shown) of the liquid crystal display device This is to increase the uniformity of the light reaching the panel (not shown) of the liquid crystal display device by proceeding perpendicular to.

As illustrated in FIG. 16, the front prisms 440 may have a trapezoidal shape having a vertical cross section, and a reverse groove type having a predetermined radius of curvature as shown in FIG. 17. May have

In this case, when the vertical cross-sectional shapes of the front prisms 440 are trapezoidal as illustrated in FIG. 16, light passes through a plane A formed on each of the trapezoidal front prisms 440. It may be able to proceed perpendicular to (not shown).

In addition, as shown in FIG. 17, when the side surfaces of the front prism 360 have a reverse groove shape having a predetermined radius of curvature, the radius of curvature of the side surfaces of the front prisms 360 may be 0.01 to 1.0 mm.

The area ratio of the area occupied by the front prisms 440 and the separation plane between the front prisms 440 in the front surface 403 of the light guide plate 400 may be in a range of 1: 0.5 to 1:10. desirable.

14 to 16, the ratio of the height h2: width w2 of each of the front prisms 360 may be in the range of 0.3 to 0.6, because This is because when the ratio is 0.3 or less, the horizontal viewing angle becomes larger than necessary to reduce luminance, and when 0.6 or more, the horizontal viewing angle becomes too small to satisfy optical characteristics.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above embodiments but may be manufactured in various forms, and having ordinary skill in the art to which the present invention pertains. It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Therefore, the true technical protection scope of the present invention will be defined by the claims below.

In the light guide plate according to the present invention, in forming a cross prism and a main prism on a rear surface, an interference pattern generated due to the interference of the cross prism and the main prism by irregularly forming an outline of a stripe pattern or a dot pattern in which the main prism is arranged And the effect of preventing moiré phenomenon.

In addition, the light guide plate for the liquid crystal display device according to the embodiments of the present invention increases the amount of light reaching the panel of the liquid crystal display device uniformly throughout the panel and increases the amount of light traveling in the vertical direction. Compared with the light guide plate, it brings about the effect of improving the brightness, uniformity and visibility.

Claims (21)

A light guide plate for a liquid crystal display device comprising a side on which light is incident, a front surface connected to the side surface, and a rear surface reflecting light. It is provided with a plurality of irregularly shaped random stripe pattern that increases in width as the distance away from the side of the light incident on the back, A main prism formed in a direction perpendicular to a direction in which light is incident inside the random stripe pattern; A light guide plate for a liquid crystal display device comprising a cross prism outside the random stripe pattern. The method of claim 1, A light guide plate for a liquid crystal display device, characterized in that the angle formed between the main prism and the cross prism is 70 degrees to 110 degrees. The method of claim 1, The angle between the main prism and the cross prism is 90 °, the light guide plate for a liquid crystal display device. The method of claim 1, The maximum random ratio of the pattern prism is a light guide plate for a liquid crystal display device, characterized in that 1.5 to 15% of the width of the spacer region. The method of claim 1, The light guide plate for the liquid crystal display device, characterized in that the maximum random ratio of the pattern prism is 2 to 10% of the width of the spacer region. A light guide plate for a liquid crystal display device comprising a side on which light is incident, a front surface connected to the side surface, and a rear surface reflecting light. It has a plurality of dot patterns on the back, the dot pattern is made of a set of main prisms formed in the longitudinal direction perpendicular to the direction in which light is incident, A light guide plate for a liquid crystal display device, wherein each dot pattern is irregularly formed in an outline thereof. The method of claim 6, A light guide plate for a liquid crystal display device, characterized in that a cross prism is formed in an area of the back surface except for the dot pattern. The method of claim 7, wherein The longitudinal direction of the cross prism is a light guide plate, characterized in that having an angle in the range of 60 to 120 degrees with the longitudinal direction of the main prism. The method of claim 7, wherein The cross section of the cross prism and the main prism is a light guide plate, characterized in that the triangular, trapezoidal shape, the reverse side groove shape having a predetermined radius of curvature or a combination thereof. The method of claim 7, wherein The cross-prism is a cross-sectional shape of a light guide plate, characterized in that the vertex angle of 100 ° to 160 °. The method of claim 7, wherein The main prism has a triangular cross-sectional shape, and a light guide plate having a vertex angle of 70 ° to 100 °. The method of claim 7, wherein A light guide plate, characterized in that the main prism is a groove type or a reverse groove type having a predetermined radius of curvature. The method of claim 12, A light guide plate, characterized in that the main prism is a groove type or inverse groove type having a radius of curvature corresponding to 1: 1 to 1:30 with respect to the pitch. The method according to claim 1 or 6, A light guide plate, characterized in that the front surface prism having a predetermined cross-sectional shape is formed on the front surface. The method of claim 14, The longitudinal direction of the front prism is characterized in that the light guide plate perpendicular to the longitudinal direction of the main prism. The method of claim 14, A light guide plate, characterized in that the cross-section of the front prism is one of the triangle, trapezoidal shape and the reverse groove shape of the side surface has a predetermined radius of curvature. The method of claim 14, The front prism is disposed on a predetermined spacing plane. The method of claim 17, A light guide plate, wherein the area ratio occupied by the front prism and the spaced plane therebetween is in a range of 1: 0.5 to 1:10. The method of claim 15, Light guide plate, characterized in that the ratio of the height (h ₂ ): the width (w ₂ ) of the front prism is 0.3 to 0.6. The light guide plate of claim 1; And And a light source disposed at one side of the light guide plate. The light guide plate of claim 1; And And a light source disposed at one side of the light guide plate.

Images