KR100875491B1 - Light guide plate, backlight unit and liquid crystal display device using the same - Google Patents

Abstract

The present invention relates to a light guide plate of a backlight unit (Back Light Unit), the first light incident region (L1) from the light incident surface facing the light source to the point where the inclined portion (Wedge) starts; the point where the inclined portion starts and the inclined portion ends A second light incident region L2 up to; a third light incident region L3 up to the point where the inclined portion ends and the effective region starts; And a hot spot suppression region formed in the first light incident region L1 to have a lower refractive index than the other regions, and to have a configuration that is easy to manufacture a thin light guide plate while suppressing a hot spot. .

Description

Light guide plate, back light unit and liquid crystal display device using the same

1 is a block diagram showing a hot spot phenomenon of the backlight unit

FIG. 2 is a configuration diagram illustrating a length change of a lighting area for solving a hot spot phenomenon of a backlight unit in the related art. FIG.

3a and 3b is a configuration diagram for explaining the hot spot generating portion and the dark portion generating portion in the prior art

Figures 4a and 4b is another configuration diagram for explaining the hot spot generating portion and the dark portion generating portion in the prior art

5 is a block diagram illustrating the light guide plate of the backlight unit according to the present invention divided into regions;

6 is a plan view illustrating a light guide plate of a backlight unit according to a first embodiment of the present invention;

7A to 9B are cross-sectional configuration diagrams of a light guide plate of the backlight unit according to the first embodiment of the present invention.

10 is a plan view illustrating a light guide plate of a backlight unit according to a second exemplary embodiment of the present invention.

11A to 13B are cross-sectional configuration views of a light guide plate of a backlight unit according to a second embodiment of the present invention.

14 is a plan view illustrating a light guide plate of a backlight unit according to a third exemplary embodiment of the present invention.

15A to 17B are cross-sectional configuration views of a light guide plate of a backlight unit according to a third embodiment of the present invention.

18 is a plan view of a light guide plate of a backlight unit according to a fourth embodiment of the present invention;

19A to 21B are cross-sectional configuration views of a light guide plate of a backlight unit according to a fourth embodiment of the present invention.

22 is a plan view illustrating a light guide plate of a backlight unit according to a fifth embodiment of the present invention;

23A to 25B are cross-sectional configuration diagrams of a light guide plate of a backlight unit according to a fifth embodiment of the present invention;

26 is a plan view illustrating a light guide plate of a backlight unit according to a sixth exemplary embodiment of the present invention.

27A to 29B are cross-sectional configuration diagrams of a light guide plate of a backlight unit according to a sixth embodiment of the present invention;

30A to 32B are diagrams showing light propagation characteristics according to a structure of a light guide plate of a backlight unit according to the present invention.

33 is a plan view illustrating a light guide plate of a backlight unit according to a seventh embodiment of the present invention;

34A to 36B are cross-sectional views and light propagation characteristics of a light guide plate of a backlight unit according to a seventh exemplary embodiment of the present invention.

37A to 37B are diagrams illustrating plan and cross-sectional structures of a light guide plate of a backlight unit according to an eighth embodiment of the present invention.

38A to 40B are diagrams illustrating light propagation characteristics of a backlight unit according to an eighth embodiment of the present invention.

41A to 46B are photographs showing hot spot characteristics according to the light guide plate structure of the backlight unit according to the seventh and eighth embodiments of the present invention;

47 is a plan view of a light guide plate having a hot spot suppressing region in the form of a stripe prism according to the present invention.

48 is a configuration diagram of a backlight unit including a light guide plate having a hot spot suppression region in the form of a stripe prism according to the present invention.

49 is a configuration diagram of a liquid crystal display including a light guide plate having a stripe prism type hot spot suppression region according to the present invention.

Explanation of symbols for the main parts of the drawings

47a.47b. Hotspot Suppression Area 48.LED

200. Light guide plate 300. Diffusion plate

400. Prism sheet 500. Reflector

600. Shading Tape 700. Liquid Crystal Panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to forming a hot spot suppression region in any one of various shapes including a prism shape in a lighting area of a light guide plate constituting a backlight unit. The present invention relates to a light guide plate, a backlight unit using the same, and a liquid crystal display device capable of suppressing hot spots and improving light uniformity.

In general, a liquid crystal display (LCD), which is one of flat panel display devices, has better visibility than cathode ray tube (CRT) and has a lower average power consumption than a CRT of the same screen size, and generates less heat. Along with Display Pannel (PDP) and Field Emission Display, it is recently attracting attention as the next generation display of mobile phones, laptops, computer monitors and televisions.

The liquid crystal display device displays an image corresponding to the video signal by adjusting the light transmittance of the liquid crystal cells arranged in a matrix form to the video signal supplied thereto.

Accordingly, the liquid crystal display device includes a liquid crystal panel in which liquid crystal cells for adjusting a transmission amount of light projected from the lower portion are arranged in an active matrix form, and a backlight unit for projecting light from the lower portion of the liquid crystal panel. ), And a red, green, and blue color filter and a black matrix layer for distinguishing pixels formed on the upper surface of the liquid crystal panel for each liquid crystal cell.

Accordingly, the side type backlight unit, in which a lamp is provided on the side of the liquid crystal panel and provides light to the liquid crystal layer, is installed on the side of the liquid crystal panel so that light can be supplied to the liquid crystal layer through the reflector and the light guide plate, thereby reducing the overall thickness. have.

Therefore, it is mainly used for mobile phones, PDAs, vehicle navigation, laptops and monitors, TVs, and the like.

However, since the LED lamp emitting light beams is located on the side of the liquid crystal panel, the straightness of the light beams is high, causing problems such as bright lines and hot spots, and thus, the product characteristics such as uniformity of the backlight unit are deteriorated. It is difficult to apply to large liquid crystal panels such as large monitors, notebooks, and TVs.

Hereinafter, a backlight unit and a light guide plate constituting the backlight unit of the liquid crystal display according to the related art will be described with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating a hot spot phenomenon of a backlight unit, and FIG. 2 is a diagram illustrating a change in the length of a lighting area for solving a hot spot phenomenon of a backlight unit in the related art.

As illustrated in FIG. 1, a hot spot refers to a phenomenon in which a light spot of a LED used as a light source or between a plurality of the LEDs is brighter or darker than the surroundings. The hot spot may occur when proper light is not reflected in a predetermined pattern located on the rear surface of the light guide plate.

In addition, the spacing between the light source of the LED and the light guide plate may occur even when assembled.

The light guide plate of the backlight unit of the prior art generally has a configuration to reduce the occurrence of hot spots by forming a predetermined pattern on the light incident surface of the edge portion of the light guide plate, or by forming a predetermined pattern on the back surface of the light guide plate.

However, the conventional light guide plate is not easy to reduce the occurrence of hot spots due to the problem of pattern design or assembly.

In the prior art, in order to solve the problem of hot spots as shown in FIG. 2, a method of changing the length and angle of the inclined portion (Wedge) in the light guide plate, inserting a pattern into the inclined portion, or changing the pattern on the rear surface of the light guide plate is disclosed. use.

That is, the method of suppressing hot spots is mainly used by changing the length and angle of the inclined portion, changing the length of the light incident portion, changing the light guide plate thickness, changing the shape of the teeth of the light incident surface, and changing the pattern.

Looking at the hot spot removal technology of the prior art as follows.

3A and 3B are diagrams for explaining a hot spot generating portion and a dark portion generating portion in the prior art, and FIGS. 4A and 4B are diagrams for explaining a hot spot generating portion and a dark portion generating portion in the prior art.

The light guide plate of FIGS. 3A and 3B and the light guide plate of FIGS. 4A and 4B are simulated under the same conditions, and have a structure in which the thickness of the light guide plate, the length of the lighted area (area), and the angle of the wedge are different.

The lighting area length (area) of the light guide plate of FIGS. 3A and 3B is 1.52 mm, and the angle of the wedge is 52 °. 4A and 4B, the length (area) of the lighting area of the light guide plate of FIG. 4A is 2.54 mm, and the angle of the wedge is 7 °.

As a result of this simulation, it can be seen that the hot spot decreases as the angle of the inclined portion of the light incident region where the sheets are stacked is closer to the traveling direction of the incident light beam.

In addition, as the length from the lighting area to the active area becomes longer, it is understood that the occurrence of dark areas is reduced, so that relative hot spot suppression is possible.

In addition, as the difference between the thickness of the inclined portion and the thickness of the light guide plate decreases, it can be seen that the hot spot can be reduced due to the light guide.

However, the method of further increasing the length of the lighting area and increasing the thickness of the light guide plate is limited in terms of design or application technology.

Therefore, due to the problems described above, the light guide plate and the backlight unit manufactured by applying the same in the prior art are not easy to suppress the occurrence of hot spots, and thus the efficiency of the light quality is poor and the light uniformity is limited. Therefore, when applied to a product such as a liquid crystal panel there is a problem that does not have any reliability.

The present invention is to solve the problems of the light guide plate constituting the backlight unit and the backlight unit of the liquid crystal display device of the prior art, and to reduce the thickness of the light guide plate and at the same time reduce the occurrence of hot spots The purpose is to provide a light guide plate.

Another object of the present invention is to provide a backlight unit of a liquid crystal display device which reduces the hot spots while reducing the length of the light incident region of the light guide plate.

Another object of the present invention is to provide a light guide plate of a backlight unit that can be easily processed and injected in a manufacturing process and can be easily changed in processing.

The present invention provides a light guide plate, a backlight unit using the same, and a liquid crystal display device, which can suppress hot spots and improve light uniformity by forming various types of hot spot suppression areas including a prism shape in a light receiving area of the light guide plate. The purpose is to provide.

The light guide plate according to the present invention for achieving the above object comprises a first light incident region (L1) from the light incident surface facing the light source to the point where the inclined portion (Wedge) starts; 2 light receiving region L2; third light receiving region L3 to the point where the inclined portion ends and the effective region starts; And a hot spot suppression region formed in the first light incident region L1 to have a lower refractive index than the other regions.

Here, the thickness of the first light incident region is the size of T1 + T2 + T3, the thickness of the second light incident region is gradually reduced from the size of T1 + T2 + T3 to the size of T2 + T3, and has a slope, and the third light incident region Is preferably T2 + T3.

And it is preferable that the center of the light source is located in the thickness portion of T3 on the light incident surface of the light guide plate.

In addition, the size of the hot spot suppression region formed in the first light incident region L1 is preferably smaller than or equal to the length of L1.

According to another aspect of the present invention, a light guide plate includes: a first light incident region L1 from a light incident surface opposite to a light source to a point at which a slope is started; a second from a slope to a point at which the slope is finished; A light incident region L2; a third light incident region L3 to the point where the inclined portion ends and the effective region starts; And a hot spot suppression region formed in the third light incident region L3 to have a lower refractive index than the other regions.

According to another aspect of the present invention, a light guide plate includes: a first light incident region L1 from a light incident surface opposite to a light source to a point at which a slope is started; a second from a slope to a point at which the slope is finished; A light incident region L2; a third light incident region L3 to the point where the inclined portion ends and the effective region starts; The first and second inclined surfaces of the first light incident region L1 having inclinations in opposite directions at one point and corresponding distances from each other toward the first light receiving region L1 so as to have a lower refractive index than the other regions, and are separated from each other from the bottom to the top thereof. It characterized in that the first inclined surface includes a hot spot suppression region formed in the form of a stripe prism facing the light incident surface.

According to another aspect of the present invention, there is provided a backlight unit including: an LED array having a plurality of LED light sources and arranged in correspondence to a light guide plate; a first light incident region from a light incident surface opposite to a light source to a point where a wedge is started; (L1), the second light incident region L2 from the inclination portion to the point where the inclination portion ends, the third light incidence region L3 from the inclination portion to the point where the effective region starts, so as to have a lower refractive index than the other regions A light guide plate comprising a hot spot suppression region formed in the first light incident region (L1), and diffuses, refracts, and reflects the light beam; Diffusion plate and prism sheet for adjusting the diffusion and propagation direction of the light source via the light guide plate; And a reflecting plate for reflecting light rays directly under the light guide plate and a light shielding tape for shielding.

According to another aspect of the present invention, there is provided a backlight unit including: an LED array having a plurality of LED light sources and arranged in correspondence to a light guide plate; a first light incident region from a light incident surface opposite to a light source to a point where a wedge is started; (L1), the second light incident region L2 from the inclination portion to the point where the inclination portion ends, the third light incidence region L3 from the inclination portion to the point where the effective region starts, so as to have a lower refractive index than the other regions A light guide plate including a hot spot suppression region formed in the third light incident region L3 and diffusing, refracting, and reflecting light rays; a diffusion plate and a prism sheet for adjusting a diffusion and propagation direction of the light source passing through the light guide plate; And a reflecting plate for reflecting light rays directly under the light guide plate and a light shielding tape for shielding.

According to another aspect of the present invention, there is provided a liquid crystal display device including: an LED array having a plurality of LED light sources and arranged in correspondence to a light guide plate; a first light incident point from a light incident surface opposite to the light source to a point where a wedge is started; Region L1, the second incident region L2 from the beginning of the inclined portion to the end of the inclination portion, the third incident region L3 from the inclination portion to the point at which the effective region begins, and a lower refractive index than the other regions A light guide plate including a hot spot suppression region formed in the first light incident region L1 to diffuse, refract, and reflect light, a diffuser plate and a prism sheet for controlling the diffusion and propagation directions of the light source passing through the light guide plate; A backlight unit including a reflector for reflecting light beams directly from the light source or the light guide plate, and a shielding tape for shielding; The liquid crystal cells for adjusting the amount of light to be transmitted are arranged in an active matrix form and include a liquid crystal panel that displays an image by the light projected by the backlight unit.

According to another aspect of the present invention, there is provided a liquid crystal display device including: an LED array having a plurality of LED light sources and arranged in correspondence to a light guide plate; a first light incident point from a light incident surface opposite to the light source to a point where a wedge is started; Region L1, the second incident region L2 from the beginning of the inclined portion to the end of the inclination portion, the third incident region L3 from the inclination portion to the point at which the effective region begins, and a lower refractive index than the other regions A light guide plate including a hot spot suppression region formed in the third light incident region L3 to diffuse, refract, and reflect light, a diffuser plate and a prism sheet for adjusting the diffusion and propagation directions of the light source passing through the light guide plate; A backlight unit including a reflector for reflecting light beams directly from the light source or the light guide plate, and a shielding tape for shielding; Is characterized in that it comprises a liquid crystal panel in which the liquid crystal cells for adjusting the amount of light transmitted are arranged in an active matrix to display an image by the light projected by the backlight unit.

Hereinafter, the liquid crystal display according to the present invention may form a hot spot suppression region having various shapes including a prism shape in the light incident region of the light guide plate constituting the backlight unit to suppress hot spots and to improve light uniformity. The preferred embodiment of the backlight unit of the device is described in detail as follows.

Features and advantages of the backlight unit of the liquid crystal display according to the present invention will be apparent from the detailed description of each embodiment below.

5 is a block diagram illustrating the light guide plate of the backlight unit according to the present invention.

The present invention forms a hot spot suppression region in one of several shapes including a prism shape in the light incident region of the light guide plate to suppress hot spots and to improve light uniformity.

The present invention provides a light guide plate designed to uniformly induce hot spot removal and light spread using this principle.

The structure for forming the hot spot suppression region according to the present invention will be described.

In FIG. 5, L1 + L2 + L3 is the total length of the lighting area, L1 is the first light incidence area from the light incidence surface of the light guide plate to the point where the inclination is started, and L2 is the inclination part starting and inclining. A second light incident region up to the point where the addition ends, and L3 is a third light incident region up to the point where the inclined portion ends and the effective region starts.

T1 + T2 + T3 is the same as the thickness of the LED used as the light source, and is the thickness of the first light incident region L1.

T2 + T3 is the thickness of the third light incident region L3 and the effective region, and T3 is the thickness from the lower surface of the light guide plate to the center of the light source.

And T1 is the thickness in which the inclination part except the thickness (T2 + T3) of the 3rd light incident area | region L3 is formed.

Here, in a preferred embodiment of the light guide plate according to the present invention, the thickness T1 in which the inclined portion except the thickness T2 + T3 of the effective region is formed is 0.2 mm, and the thickness T2 from the upper surface of the effective region to the center of the light source is 0.4. mm.

The length L1 of the first light incident region is 0.42 mm, the length L2 of the second light incident region is 0.15 mm, and the length L3 of the third light incident region is 2 mm.

In the present invention, the hot spot suppression region for suppressing the hot spot may be formed in the form of a groove or a hole, a prism, or a stripe prism, but is formed in the first light incident region L1 and the third light incident region L3 except the inclined portion.

In the case where the first light incident region L1 is formed, the size of the hot spot suppression region is formed to be smaller than or equal to the length of L1-0.05 mm, and in the third light incident region L3, of course, Form less than or equal to length

In the case where the first light incident region L1 is formed, the depth of the hot spot suppression region is greater than or equal to T1 and smaller than or equal to T1 + T2, or smaller than T1 + T2 + T3.

The light guide plate constituting the backlight unit and the backlight unit of the liquid crystal display according to the present invention having such a mood structure will be described.

First, the light guide plate of the backlight unit according to the first embodiment of the present invention will be described.

6 is a plan view illustrating the light guide plate of the backlight unit according to the first embodiment of the present invention, and FIGS. 7A to 9B illustrate cross-sectional views of the light guide plate of the backlight unit according to the first embodiment of the present invention.

In a first embodiment of the present invention, a hot spot suppression region is formed in an air triangle shape in a first light incident region L1 of a light guide plate.

Here, the hot spot suppression region is formed at the vertex of the empty triangle (air triangle) toward the light source and the lower side toward the effective region.

Referring to the cross-sectional structure taken along the line AA ′ of FIG. 6, FIG. 7A is a hot spot suppression region formed on the first light incident region L1 and formed in a triangular structure at a predetermined depth, as shown in FIG. 7B. It can be seen that the spreading properties are improved and the hot spots are reduced.

FIG. 8A shows that the hot spot suppressing region is formed under the first light incident region L1. As shown in FIG. 8B, light spreading characteristics are improved.

FIG. 9A illustrates a hot spot suppression region penetrating through the first light incident region L1 and is formed in the same size as the thickness of the first light incident region L1 in a triangular structure. As shown in FIG. 9B, light spreading characteristics are improved. It can be seen that the hot spot is reduced.

The light guide plate of the backlight unit according to the second embodiment of the present invention will be described.

10 is a plan view illustrating a light guide plate of a backlight unit according to a second embodiment of the present invention, and FIGS. 11A to 13B illustrate cross-sectional views of a light guide plate of a backlight unit according to a second embodiment of the present invention.

According to the second exemplary embodiment of the present invention, a hot spot suppression region is formed in an air triangle shape in the third light incident region L3 of the light guide plate.

Here, the hot spot suppression region is formed at the vertex of the empty triangle (air triangle) toward the light source and the lower side toward the effective region.

Referring to the cross-sectional structure taken along the line B-B 'of FIG. 10, FIG. 11A is a hot spot suppression region formed on the third light incident region L3, and is formed to have a predetermined depth in a triangular structure, and as shown in FIG. It can be seen that the spreading characteristics are improved.

12A illustrates that the hot spot suppressing region is formed under the third light incident region L3, and the light spreading characteristic is improved as in FIG. 12B.

FIG. 13A illustrates a hot spot suppression region penetrating through the third light incident region L3 and is formed in the same size as the thickness of the third light incident region L3 in a triangular structure and improves light spreading characteristics as shown in FIG. 12B. It can be seen that.

The light guide plate of the backlight unit according to the third embodiment of the present invention will be described.

14 is a plan view illustrating a light guide plate of a backlight unit according to a third embodiment of the present invention, and FIGS. 15A to 17B illustrate cross-sectional views of a light guide plate of a backlight unit according to a third embodiment of the present invention.

According to the third embodiment of the present invention, a hot spot suppressing region is formed in an empty lens shape in the first light incident region L1 of the light guide plate.

Here, the hot spot suppressing area is formed with the convex lens surface of the air lens type (Air Lenticular) toward the light source and the lower side toward the effective area.

Referring to the cross-sectional structure taken along the line C-C 'of FIG. 14, FIG. 15A is a hot spot suppression region formed on the first light incident region L1 and has a convex lens region. As can be seen, light spreading characteristics are improved and hot spots are reduced.

In FIG. 16A, the hot spot suppressing region is formed under the first light incident region L1, and as shown in FIG. 16B, light spreading characteristics are improved.

FIG. 17A is a structure in which a hot spot suppression region is formed through the first light incident region L1 and has a convex lens region, and is formed to have the same size as the thickness of the first light incident region L1, and is light spread as shown in FIG. 17B. It can be seen that the properties are improved and the hot spots are reduced.

The light guide plate of the backlight unit according to the fourth embodiment of the present invention will be described.

18 is a plan view illustrating a light guide plate of a backlight unit according to a fourth embodiment of the present invention, and FIGS. 19A to 21B illustrate cross-sectional views of a light guide plate of a backlight unit according to a fourth embodiment of the present invention.

According to the fourth embodiment of the present invention, a hot spot suppressing region is formed in an empty lens shape in the third light incident region L3 of the light guide plate.

Here, the hot spot suppressing area is formed with the convex lens surface of the air lens type (Air Lenticular) toward the light source and the lower side toward the effective area.

Referring to the cross-sectional structure taken along the line D-D 'of FIG. 18, FIG. 19A is a hot spot suppression region formed on the third light incident region L3 to have a convex lens region, and is formed to have a predetermined depth, and FIG. 19B. It shows the light spreading characteristics as in

FIG. 20A shows a light spreading characteristic as shown in FIG. 20B, in which a hot spot suppressing region is formed below the third light incident region L3.

FIG. 21A is a structure in which a hot spot suppression region is formed through the third light incident region L3, and has a convex lens region, and is formed to have the same size as the thickness of the third light incident region L3, and is light spread as shown in FIG. 21B. Characteristics.

The light guide plate of the backlight unit according to the fifth embodiment of the present invention will be described.

22 is a plan view illustrating a light guide plate of a backlight unit according to a fifth embodiment of the present invention, and FIGS. 23A to 25B illustrate cross-sectional views of a light guide plate of a backlight unit according to a fifth embodiment of the present invention.

In the fifth embodiment of the present invention, a hot spot suppression region is formed in an air circle shape in the first light incident region L1 of the light guide plate.

Referring to the cross-sectional structure taken along the line E-E 'of FIG. 22, FIG. 23A is formed by forming a hot spot suppression region on an upper portion of the first light incident region L1 to a predetermined depth, and has a light spreading characteristic as shown in FIG. 23B. It can be seen that the improvement and the hot spot are reduced.

FIG. 24A shows a hot spot suppressing region formed under the first light incident region L1 and has the same characteristics as in FIG. 24B.

FIG. 25A illustrates a hot spot suppression region penetrating through the first light incident region L1 and is formed to have the same size as the thickness of the first light incident region L1. As shown in FIG. 25B, light spreading characteristics are improved and hot spots are reduced. It can be seen that.

The light guide plate of the backlight unit according to the sixth embodiment of the present invention will be described.

FIG. 26 is a plan view illustrating a light guide plate of a backlight unit according to a sixth embodiment of the present invention, and FIGS. 27A to 29B illustrate cross-sectional views of a light guide plate of a backlight unit according to a sixth embodiment of the present invention.

In a sixth exemplary embodiment of the present invention, a hot spot suppression region is formed in an air circle shape in a third light incident region L3 of a light guide plate.

Referring to the cross-sectional structure taken along the line F-F 'of FIG. 26, FIG. 27A is formed by forming a hot spot suppression region on the upper portion of the third light incident region L3 to a predetermined depth, and exhibits light spreading characteristics as shown in FIG. 27B. Indicates.

FIG. 28A shows a hot spot suppressing region formed under the third light incident region L3 and has the same characteristics as in FIG. 28B.

FIG. 29A shows a hot spot suppression region formed through the third light incident region L3 and is formed to have the same size as the thickness of the third light incident region L3 and has the same characteristics as in FIG. 29B.

As described above, the light propagation path and the characteristic change when the hot spot suppression region is formed in the first light incident region L1 of the light guide plate are as follows.

30A to 32B are diagrams illustrating light propagation characteristics of the light guide plate of the backlight unit according to the present invention.

Since the portion where the hot spot suppression region is formed has a low refractive index and the other portion has a high refractive index, the light propagation path is different due to the change in the formation position of the hot spot suppression region.

In the case of forming the hot triangle suppressing area of the air triangle in the first light incident area L1, the hot spot suppressing effect is excellent. In the case of forming the hot triangle suppressing area in the third light incident area L3, the dark area removal and light spreading characteristics are mainly achieved. Improve.

In the case of the air lens type (Air Lenticula), the hot spot suppression portion is mainly improved.

The light guide plate of the backlight unit according to the seventh embodiment of the present invention will be described.

33 is a plan view illustrating the light guide plate of the backlight unit according to the seventh embodiment of the present invention, and FIGS. 34A to 36B illustrate cross-sectional structures and light propagation characteristics of the light guide plate of the backlight unit according to the seventh embodiment of the present invention. It is a block diagram.

As shown in FIG. 33, the light guide plate of the backlight unit according to the seventh exemplary embodiment forms a prism-shaped hot spot suppression region only in front of the light source of the first light incident region L1.

FIG. 34A shows that the angle of incidence plane A (the side close to the light source) of the light beam is formed at 45 degrees, and the angle of the emission surface B (the side close to the effective area) is formed at 45 degrees.

34B illustrates light propagation characteristics in a cross section of the light guide plate having the structure of FIG. 34A, and FIG. 34C shows light propagation characteristics in a plane, and it is understood that suppression of hot spots and light spreading characteristics are improved.

FIG. 35A shows that the angle of incidence plane A (the side close to the light source) of the light beam is formed at 60 ° and the angle of the emission surface B (the side close to the effective area) is formed at 45 °.

FIG. 35B illustrates light propagation characteristics in the cross section of the light guide plate having the structure of FIG. 35A, and FIG. 35C shows light propagation characteristics in a plane, and it can be seen that the suppression of hot spots and light spreading characteristics are improved.

36A shows that the angle of incidence plane A (the side close to the light source) of the light beam is formed at 80 ° and the angle of the emission surface B (the side close to the effective area) is formed at 45 °.

FIG. 36B illustrates light propagation characteristics in a cross section of the light guide plate having the structure of FIG. 36A, and FIG. 36C shows light propagation characteristics in a plane, and it can be seen that the suppression of hot spots and light spreading characteristics are improved.

Naturally, the formation angles of the incidence surface A and the emission surface B of the prism can be formed to have different values as well as the above embodiments.

A light guide plate of a backlight unit according to an eighth embodiment of the present invention will be described.

37A to 37B are schematic diagrams illustrating a planar and cross-sectional structure of a light guide plate of a backlight unit according to an eighth embodiment of the present invention, and FIGS. 38A to 40B illustrate light propagation of a backlight unit according to an eighth embodiment of the present invention. It is a block diagram showing the characteristic.

In the light guide plate of the backlight unit according to the eighth embodiment of the present invention, as shown in FIGS. 37A and 37B, a hot spot suppression region having a stripe prism shape is formed in the first light incident region L1.

38A shows that the angle of incidence plane A (the side close to the light source) of the light beam is formed at 30 degrees, and the angle of the emission surface B (the side close to the effective area) is formed at 45 degrees.

38B shows light propagation characteristics in a plane, and it can be seen that hot spot suppression and light spreading characteristics are improved.

39A shows that the angle of incidence plane A (the side close to the light source) of the light beam is formed at 45 ° and the angle of the emission surface B (the side close to the effective area) is formed at 45 °.

39B shows light propagation characteristics in a plane, and it can be seen that hot spot suppression and light spreading characteristics are improved.

40A shows that the angle of incidence plane A (the side close to the light source) of the light beam is formed at 90 ° and the angle of the emission surface B (the side close to the effective area) is formed at 45 °.

40B shows light propagation characteristics in a plane, and it can be seen that hot spot suppression and light spreading characteristics are improved.

As a matter of course, the angles of incidence of the incidence surface A and the emission surface B of the stripe prism can be formed to have different values as well as the above embodiments.

The hot spot characteristics of the light guide plate according to the seventh embodiment having the prism type hot spot suppression region and the eighth embodiment having the stripe prism type hot spot suppression region are as follows.

41A to 46B are photographs illustrating hot spot characteristics of the light guide plate structure of the backlight unit according to the seventh and eighth embodiments of the present invention.

FIG. 41A shows a light guide plate having a prism-shaped hot spot suppression region formed by forming an angle of incidence plane A (the side close to the light source) of the light beam at 15 ° and an angle of the exit plane B (the side close to the effective area) at 45 °. Hotspot characteristics in the plane are shown.

41B shows a light guide plate having a stripe prism-shaped hot spot suppression region formed by forming an angle of incidence surface A (the side closer to the light source) of the light beam to 15 ° and an angle of the exit surface B (the side closer to the effective area) to 45 °. It shows the hot spot characteristics in the plane of.

Fig. 42A shows a light guide plate having a prism-shaped hot spot suppression region formed by forming an angle of incidence plane A (the side close to the light source) of the light beam at 30 ° and an angle of the exit plane B (the side close to the effective area) at 45 °. Hotspot characteristics in the plane are shown.

Fig. 42B is a light guide plate in which the angle of incidence plane A (the side close to the light source) of the light beam is formed at 30 ° and the angle of the exit surface B (the side close to the effective area) is 45 °, forming the stripe prism type hot spot suppression region. It shows the hot spot characteristics in the plane of.

FIG. 43A shows a light guide plate having a prism-shaped hot spot suppression region formed by forming an angle of incidence plane A (the side closer to the light source) of the light beam at 45 ° and an angle of the exit plane B (the side closer to the effective area) at 45 °. Hotspot characteristics in the plane are shown.

43B shows a light guide plate having a 45 ° angle of incidence plane A (the side close to the light source) of the light beam and 45 ° of the exit surface B (the side close to the effective area) to form a hotspot suppression region in the form of a stripe prism. It shows the hot spot characteristics in the plane of.

FIG. 44A shows a light guide plate having a prism-shaped hot spot suppression region formed by forming an angle of incidence plane A (the side closer to the light source) of the light beam at 45 ° and an angle of the exit plane B (the side closer to the effective area) at 15 °. Hotspot characteristics in the plane are shown.

44B shows that the angle of incidence plane A (the side close to the light source) of the light beam is formed at 45 °, and the angle of the exit surface B (the side close to the effective area) is 15 ° to form the stripe prism type hot spot suppression region. Hot spot characteristics in the plane of the light guide plate are shown.

45A illustrates a light guide plate having a prism-shaped hot spot suppression region formed by forming an angle of incidence plane A (the side close to the light source) of the light beam at 45 ° and an angle of the exit plane B (the side close to the effective area) at 30 °. Hotspot characteristics in the plane are shown.

45B shows a light guide plate having a 45 ° angle of incidence plane A (the side closer to the light source) of the light beam and a 30 ° angle of the exit surface B (the side closer to the effective area) to form a hot spot suppression region in the form of a stripe prism. It shows the hot spot characteristics in the plane of.

Fig. 46A shows a light guide plate having a prism-shaped hot spot suppression region formed by forming an angle of incidence plane A (the side close to the light source) of the light beam at 45 ° and an angle of the exit plane B (the side close to the effective area) at 60 °. Hotspot characteristics in the plane are shown.

Fig. 46B is a light guide plate in which the angle of incidence plane A (the side close to the light source) of the light beam is formed at 45 ° and the angle of the exit surface B (the side close to the effective area) is 60 °, forming a stripe prism-shaped hot spot suppression region; It shows the hot spot characteristics in the plane of.

As described above, when forming the hot spot suppression region according to the present invention in the form of a prism or a stripe prism, the angle of the incident surface A (the side closer to the light source) of the light beam is formed in the range of 45 ° to 90 ° and is emitted. Selectively forming the angle of plane B (the side close to the effective area) in the range of 10 to 80 °, or selectively forming the angle of the incident surface A (the side closer to the light source) of the light beam in the range of 10 to 80 ° It is preferable to form the angle of B (the side near the effective area) in the range of 45 degrees-90 degrees.

The hot spot suppression region of the light guide plate according to the present invention described above has a lower refractive index than other regions of the light guide plate. Therefore, there is a possibility of total reflection conditions upon light incidence from a high refractive medium to a low refractive medium (hot spot suppressing region).

In the case of incidence from the low refractive medium (hot spot suppression region) to the high refractive medium (other regions of the light guide plate), it is incident in the normal direction with a transmission characteristic.

This property suppresses the hot spots by diverting the incident light rays from the areas where hot spots are more likely to occur.

The backlight unit structure to which the light guide plate according to the present invention described above is applied will be described.

47 is a plan view illustrating a light guide plate having a stripe prism type hot spot suppression region, and FIG. 48 is a view illustrating a backlight unit including a light guide plate having a stripe prism type hot spot suppression region according to the present invention.

In the embodiments of the light guide plate having various types of hot spot suppression regions, a light guide plate having a stripe prism type will be described in the backlight unit.

As illustrated in FIG. 47, the light guide plate according to the present invention includes hotspot suppression regions 47a and 47b in the form of stripe prisms at portions opposed to LED arrays used as light sources.

The backlight unit according to the present invention includes a LED array having a plurality of LED light sources and arranged in correspondence to a light guide plate, a first light incident region L1 from a light incident surface opposite to the light source to a point where a wedge starts, and an inclination A second light incident region L2 from which the portion starts to the end of the inclined portion, a third light incident region L3 until the slope portion ends and the effective region begins, and a first light incident region so as to have a lower refractive index than the other regions A light guide plate 200 including a hot spot suppression region formed at L1 and diffusing, refracting, and reflecting light rays, a diffusion plate 300 for controlling the diffusion and propagation direction of the light source via the light guide plate 200; And a prism sheet 400, a reflector 500 for reflecting light rays directly under the light source or the light guide plate, and a light shielding tape 600 for shielding.

According to another aspect of the present invention, a backlight unit includes a LED array having a plurality of LED light sources and arranged to correspond to a light guide plate, and a first light incident region L1 from a light incident surface opposite to the light source to a point where a wedge is started. ), A second light incident region L2 from the inclination portion to the point where the inclination portion ends, a third light incident region L3 from the inclination portion to the point where the effective region begins, and a third refractive index so as to have a lower refractive index than the other regions A light guide plate 200 including a hot spot suppression region formed in the light receiving region L3 and diffusing, refracting, and reflecting light rays, and a diffusion plate 300 for controlling the diffusion and propagation direction of the light source via the light guide plate 200. And a prism sheet 400, a reflector 500 for reflecting light beams directly under the light source or the light guide plate, and a light shielding tape 600 for light shielding.

Of course, light guide plates having various types of hot spot suppression regions as described above may be applied to the backlight unit.

The liquid crystal display device to which the light guide plate and the backlight unit according to the present invention described above are applied will be described.

49 is a configuration diagram of a liquid crystal display including a light guide plate having a stripe prism type hot spot suppression region according to the present invention.

First, the LED array having a plurality of LED light sources and arranged in correspondence with the light guide plate, the first light incident region L1 from the light incident surface facing the light source to the point where the inclined portion (Wedge) starts, the inclined portion is started A second light incident region L2 up to the ending point, a third light incident region L3 up to the point where the inclined portion ends and the effective region starts, and is formed in the first light incident region L1 so as to have a lower refractive index than the other regions A light guide plate 200 including a hot spot suppression region and diffusing, refracting, and reflecting light rays, a diffusion plate 300 and a prism sheet 400 for adjusting a diffusion and propagation direction of a light source passing through the light guide plate 200; And a backlight unit including a reflection plate 500 for reflecting light beams directly from the light source or the light guide plate, and a light shielding tape 600 for shielding light, and controlling the amount of light transmitted and coupled with the backlight unit. The liquid crystal cells are arranged in the form of active-matrix (Active Matrix) is a liquid crystal panel 700 that displays an image by the light projected by the light unit and configured.

Another type of liquid crystal display includes an LED array having a plurality of LED light sources and arranged in correspondence to a light guide plate, a first light incident region L1 from a light incident surface opposite to the light source to a point where a wedge starts; A second light incident region L2 from which the inclined portion starts to the point where the inclined portion ends, a third light incident region L3 up to the point where the inclined portion ends and the effective region starts, a third light incident region so as to have a lower refractive index than the other regions A light guide plate 200 including a hot spot suppression region formed at L3 and diffusing, refracting, and reflecting light rays, and a diffusion plate 300 for controlling the diffusion and propagation direction of the light source via the light guide plate 200. And a backlight unit including a prism sheet 400, a reflector plate 500 for reflecting light rays directly under the light source or the light guide plate, and a light shielding tape 600 for shielding light, A liquid crystal cell for controlling the transmission amount of light that are arranged to form an active matrix (Active Matrix) is configured to include a liquid crystal panel 700 that displays an image by the light projected by the light unit.

The light guide plate according to the present invention described above, the backlight unit to which the same is applied, and the liquid crystal display device suppress hot spots by forming various types of hot spot suppression regions including prism shapes in the light incident region of the light guide plate constituting the backlight unit. At the same time, the light uniformity can be improved.

The above descriptions are merely illustrative of the technical idea of the present invention, and those skilled in the art may of course make modifications without departing from the essential characteristics of the present invention. Therefore, the technical idea of the present invention is not limited to the above embodiment.

Such a light guide plate according to the present invention, a backlight unit using the same, and a liquid crystal display device have the following effects.

Various types of hot spot suppression regions including a prism shape may be formed in the light incident region of the light guide plate constituting the backlight unit to suppress hot spots and to improve light uniformity.

In addition, due to the above configuration, even if the length of the light incident portion of the light guide plate is short, it is possible to effectively reduce the hot spot.

Further, by forming the hot spot suppression region of the light guide plate in the shape of a plate-shaped prism in a direction perpendicular to the light source, it is easy to process and inject in the manufacturing process and at the same time, easy to change.

Claims (33)

A first light incident region L1 from the light incident surface opposite to the light source to the point where the inclined portion Wedge starts; A second light incident region L2 from the inclination part to the point where the inclination part ends; A third light incident region L3 to the point where the inclined portion ends and the effective region starts; And And a hot spot suppression region formed at a central portion corresponding to the light source of the first light incident region L1. The hot spot suppression region may be formed to have a refractive index smaller than that of the first light incident region (L1), the second light incident region (L2), and the third light incident region (L3) except for the hot spot suppression region. The method of claim 1, wherein the thickness of the first light incident region is a size of T1 + T2 + T3, the thickness of the second light incident region is gradually reduced from the size of T1 + T2 + T3 to the size of T2 + T3, and has an inclination, The thickness of the third light incident region is T2 + T3. The light guide plate according to claim 2, wherein a central portion of the light source is located at a thickness portion of T3 at the light incident surface of the light guide plate. The light guide plate according to claim 2, wherein the size of the hot spot suppression region formed in the first light incident region (L1) is smaller than or equal to the length of L1. The light guide plate according to claim 2, wherein the depth of the hot spot suppression region formed in the first light incident region L1 is greater than or equal to T1 and less than or equal to T1 + T2, or smaller than T1 + T2 + T3. . 2. The hot-slope suppression area according to claim 1, wherein the hot spot suppression area has a first and second inclined surfaces having inclinations in opposite directions at one point, and corresponding distances from one another to a greater distance from a lower part to an upper one, and wherein the first inclined surface is inclined. The light guide plate which is opposed to the light surface. The light guide plate according to claim 1, wherein the hot spot suppression region is formed in the shape of a circular or polygonal groove or hole, a prism, or a stripe prism. The light guide plate according to claim 7, wherein when the hot spot suppression region is formed in the shape of a groove or a hole of an air triangle structure, the light guide plate is formed so that the vertices of the triangle face toward the light source and the lower side toward the effective region. 8. The light guide plate according to claim 7, wherein when the hot spot suppressing area is formed in a lens shape, the convex lens surface is formed toward the light source and the lower side toward the effective area. The light guide plate according to claim 7, wherein the hot spot suppressing region is formed in a size corresponding to the light source when the hot spot suppressing region is formed in a prism shape. The light guide plate according to claim 7, wherein the hot spot suppression region is formed to extend from one end of the light guide plate to the other end when the hot spot suppression region is formed in a stripe prism shape. 12. The method according to claim 10 or 11, wherein when the hot spot suppression region is formed in a prism form or a stripe prism form, the angle of the incident surface A (the side closer to the light source) of the light beam is formed in the range of 45 ° to 90 ° and is emitted. The light guide plate which selectively forms the angle of surface B (the side near an effective area) in the range of 10-80 degrees. 12. The method according to claim 10 or 11, wherein when the hot spot suppression region is formed in a prism shape or a stripe prism shape, the angle of the incident surface A (the side closer to the light source) of the light beam is selectively formed in the range of 10 to 80 ° and emitted. The light guide plate which forms the angle of surface B (the side near an effective area) in the range of 45 degrees-90 degrees. A first light incident region L1 from the light incident surface opposite to the light source to the point where the inclined portion Wedge starts; A second light incident region L2 from the inclination part to the point where the inclination part ends; A third light incident region L3 to the point where the inclined portion ends and the effective region starts; And And a hot spot suppression region formed at the center of a position corresponding to the light source of the third light incident region L3. The hot spot suppression region is formed with a refractive index smaller than that of the first light incident region (L1), the second light incident region (L2), and the third light incident region (L3) except the hot spot suppression region. 15. The method of claim 14, wherein the thickness of the first light incident region is the size of T1 + T2 + T3, the thickness of the second light incident region has a slope gradually decreasing from the size of T1 + T2 + T3 to the size of T2 + T3, The thickness of the third light incident region is T2 + T3. The light guide plate according to claim 15, wherein a central portion of the light source is located at a thickness portion of T3 at the light incident surface of the light guide plate. The light guide plate according to claim 15, wherein the size of the hot spot suppression region formed in the third light incident region (L3) is smaller than or equal to the length of L1. 15. The light guide plate according to claim 14, wherein the hot spot suppression region is formed in the shape of a circular or polygonal groove or hole, a prism, or a stripe prism. The light guide plate according to claim 18, wherein when the hot spot suppression region is formed in the shape of a groove or a hole of an air triangle structure, the light guide plate is formed so that the vertex of the triangle faces toward the light source and the lower side toward the effective region. The light guide plate according to claim 18, wherein when the hot spot suppressing area is formed in a lens shape, the convex lens surface is formed toward the light source and the lower side toward the effective area. A first light incident region L1 from the light incident surface opposite to the light source to the point where the inclined portion Wedge starts; A second light incident region L2 from the inclination part to the point where the inclination part ends; A third light incident region L3 to the point where the inclined portion ends and the effective region starts; And The first and second inclined surfaces of the first light incident region L1 having slopes in opposite directions at one point and correspondingly spaced apart from each other from the lower side to the upper side have a lower refractive index than the other regions. And the first inclined surface includes a hot spot suppression region formed in a stripe prism shape opposite to the light incident surface. The method of claim 21, wherein the thickness of the first light incident region is the size of T1 + T2 + T3, the thickness of the second light incident region has a slope gradually decreasing from the size of T1 + T2 + T3 to the size of T2 + T3, The thickness of the third light incident region is T2 + T3. 23. The light guide plate of claim 22 wherein the central portion of the light source is located at a thickness portion of T3 at the light incident surface of the light guide plate. The light guide plate according to claim 22, wherein the size of the hot spot suppression region formed in the first light incident region (L1) is smaller than or equal to the length of L1. The light guide plate according to claim 22, wherein the depth of the hot spot suppressing region formed in the first light incident region L1 is greater than or equal to T1 and less than or equal to T1 + T2, or smaller than T1 + T2 + T3. . An LED array having a plurality of LED light sources and arranged correspondingly to the light guide plate; The first light incident region L1 from the light incident surface opposite to the light source to the point where the inclined portion (Wedge) starts, the second light incidence region L2 from the inclined portion to the point where the inclined portion ends, the inclined portion ends and the effective region A light guide plate including a third light incident region (L3) to a starting point, a hot spot suppression region formed in the first light incident region (L1) to have a lower refractive index than the other regions, and diffusing, refracting, and reflecting light rays; A diffuser plate and a prism sheet for adjusting a diffusion and propagation direction of the light source via the light guide plate; And a reflecting plate for reflecting light beams directly under the light source or the light guide plate, and a light shielding tape for shielding. An LED array having a plurality of LED light sources and arranged correspondingly to the light guide plate; The first light incident region L1 from the light incident surface opposite to the light source to the point where the inclined portion (Wedge) starts, the second light incidence region L2 from the inclined portion to the point where the inclined portion ends, the inclined portion ends and the effective region A light guide plate including a third light incident region (L3) to a starting point, a hot spot suppression region formed in the third light incident region (L3) to have a lower refractive index than the other regions, and diffusing, refracting, and reflecting light rays; A diffuser plate and a prism sheet for adjusting a diffusion and propagation direction of the light source via the light guide plate; And a reflecting plate for reflecting light beams directly under the light source or the light guide plate, and a light shielding tape for shielding. 28. The method of claim 26 or 27, wherein the thickness of the first light incident region is a size of T1 + T2 + T3, and the thickness of the second light incident region is gradually reduced from the size of T1 + T2 + T3 to the size of T2 + T3. And a slope, and the thickness of the third light incident region is T2 + T3. 28. The backlight unit according to claim 26 or 27, wherein a central portion of the light source is located at a thickness portion of T3 at the light incident surface of the light guide plate. An LED array having a plurality of LED light sources and arranged correspondingly to the light guide plate; The first light incident region L1 from the light incident surface opposite to the light source to the point where the inclined portion (Wedge) starts, the second light incidence region L2 from the inclined portion to the point where the inclined portion ends, the inclined portion ends and the effective region A light guide plate including a third light incident region L3 up to a starting point, a hot spot suppression region formed in the first light incident region L1 to have a lower refractive index than the other regions, and diffusing, refracting, and reflecting light; A backlight unit including a diffuser plate and a prism sheet for adjusting the diffusion and propagation directions of the light source via the light guide plate, a reflector for reflecting light beams directly from the light source or the light guide plate, and a light shielding tape for shielding; And a liquid crystal panel coupled to the backlight unit and configured to adjust a transmission amount of light to be projected, including a liquid crystal panel arranged in an active matrix form to display an image by light projected by the backlight unit. Liquid crystal display. An LED array having a plurality of LED light sources and arranged correspondingly to the light guide plate; The first light incident region L1 from the light incident surface opposite to the light source to the point where the inclined portion (Wedge) starts, the second light incidence region L2 from the inclined portion to the point where the inclined portion ends, the inclined portion ends and the effective region A light guide plate including a third light incident region L3 up to a starting point, a hot spot suppression region formed in the third light incident region L3 to have a lower refractive index than the other regions, and diffusing, refracting, and reflecting light; A backlight unit including a diffuser plate and a prism sheet for adjusting a diffusion and propagation direction of the light source via the light guide plate, a reflector for reflecting light beams directly from the light source or the light guide plate, and a light shielding tape for shielding light; And a liquid crystal panel coupled to the backlight unit and configured to adjust a transmission amount of light to be projected, including a liquid crystal panel arranged in an active matrix form to display an image by light projected by the backlight unit. Liquid crystal display. 32. The method of claim 30 or 31, wherein the thickness of the first light incident region is a size of T1 + T2 + T3, and the thickness of the second light incident region is gradually reduced from the size of T1 + T2 + T3 to the size of T2 + T3. It has an inclination, and the thickness of a 3rd light incident area | region is T2 + T3, The liquid crystal display device characterized by the above-mentioned. 32. The liquid crystal display device according to claim 30 or 31, wherein a central portion of the light source is located at a thickness portion of T3 at the light incident surface of the light guide plate.

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