KR20070103944A - Liquid crystal display device - Google Patents

Abstract

A liquid crystal display device is provided to adjust a range of incident light into a light guide plate by forming a plurality of reflective protrusions on a reflective plate. A liquid crystal display device includes a liquid crystal display panel(20), a light guide plate(40), a light source unit(50) and a reflective plate(60). The light guide plate is positioned on a rear surface of the liquid crystal display panel. The light source unit is arranged at one side of the light guide plate. The reflective plate includes a plurality of reflective protrusions for surrounding the light source unit, adjusting an incident angle of incident light into the light guide plate by adjusting a reflective angle of light irradiated from the light source unit. The protrusions are integrated with the reflective plate. A sectional surface of each of the reflective protrusions is formed with a shape of polygon.

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY DEVICE}

1 is an exploded perspective view of a liquid crystal display device according to the present invention;

2A is a cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention;

2B is a cross-sectional view of a liquid crystal display device according to still another embodiment of the present invention;

3A to 3D are exemplary views showing various embodiments of the reflector according to the present invention;

4A to 4D are diagrams illustrating incident ranges of light according to embodiments of FIGS. 3A to 3D.

Explanation of Signs of Major Parts of Drawings

1 liquid crystal display 10 top cover member

20 liquid crystal display panel 30 optical film

40: light guide plate 43: prism

50: light source 60: reflector

61: projection 70: diffuser plate

80: lower cover member 90: mold

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having an improved structure of a reflecting plate.

Recently, a flat panel display such as a liquid crystal display (LCD), a plasma display panel (PDP), or an organic light emitting diode (OLED) has been developed in place of the conventional CRT.

The liquid crystal display device includes a thin film transistor substrate, a color filter substrate, and a liquid crystal display panel in which liquid crystal is injected between both substrates. Since the liquid crystal display is a non-light emitting device, a backlight unit for supplying light is disposed on the rear surface of the thin film transistor substrate. The amount of light emitted from the backlight unit is adjusted according to the arrangement state of the liquid crystal and the amount of voltage.

The backlight unit is divided into an edge type and a direct type according to the position of the light source. The edge type is a structure in which a light source is installed on the side of the light guide plate, and is mainly applied to a relatively small liquid crystal display device such as a laptop type and a desktop computer. Such an edge type backlight unit has a good light uniformity, a long service life, and is advantageous for thinning a liquid crystal display device.

The liquid crystal display using the edge type backlight unit is absorbed by the polarizer and the color filter when the light emitted from the light source is transmitted, so that the amount of light actually transmitted is only about 5% of the light generated by the initial light source. In order to increase the light utilization efficiency, the conventional liquid crystal display device increases the light utilization efficiency by adjusting the incident range of light incident on the light guide plate using a separate collimator of light generated from the light source.

However, since the use of a collimator (collimator) increases the manufacturing cost, since the collimator (collimator) is composed of a brittle material including glass, the manufacturing process is difficult and the problem of breaking well after the production occurred.

Accordingly, an object of the present invention is to provide a liquid crystal display device which can simplify the manufacturing process and increase light utilization efficiency.

An object of the present invention is a liquid crystal display panel; A light guide plate on a rear surface of the liquid crystal display panel; A light source unit disposed on at least one side of the light guide plate; And a reflection plate having a plurality of reflection protrusions to adjust the angle of incidence of the reflected light incident on the light guide plate while covering the light source portion to adjust the reflection angle of the light irradiated from the light source portion.

Here, the plurality of reflecting projections are preferably provided integrally with the reflecting plate.

In addition, the plurality of reflecting protrusions are preferably provided in a polygonal cross section.

In addition, the plurality of reflecting projections are preferably provided so that the height is different from each other.

The plurality of reflecting protrusions may be provided to increase in height as they approach the light guide plate.

In addition, the plurality of reflecting protrusions may be prisms.

The reflective plate may be provided in parallel with the light guide plate.

In addition, the reflective plate may be provided to be inclined at a predetermined angle with the light guide plate.

On the other hand, an object of the present invention and the light source; And a reflecting plate which forms a spaced space with the light source unit and is provided in a circumferential region of the light source unit, and has a reflective protrusion projecting along the spaced space to reflect light emitted from the light source unit within a predetermined angle range. Achieved by the backlight unit.

Here, it is preferable that the reflecting protrusion is provided integrally with the reflecting plate.

On the other hand, the reflective projections are preferably provided in a triangular cross section.

In addition, the reflection protrusion is preferably a prism.

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

In the following examples, the same reference numerals refer to the same components. The same components are representatively described in the first embodiment and may be omitted in other embodiments.

A liquid crystal display according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3D.

1 is an exploded perspective view of a liquid crystal display according to a first embodiment of the present invention, and FIG. 2A is a cross-sectional view of the liquid crystal display according to the first embodiment of the present invention.

The liquid crystal display device 1 includes a liquid crystal display panel 20, a plurality of optical films 30 disposed on the rear surface of the liquid crystal display panel 20, a light guide plate 40 disposed on the rear surface of the liquid crystal display panel 20, and a light guide plate 40. A pair of light source units 50 disposed along opposite side surfaces of the light source unit 50, surrounding the light source unit 50, and reflecting plate 60 to adjust an incident range of light generated from the light source unit 50 to the lower portion of the light guide plate 40. It includes a diffusion plate 70 located. These are accommodated between the upper cover member 10 and the lower cover member 80. In addition, the liquid crystal display panel 20 is mounted on the mold 90.

The liquid crystal display panel 20 includes a thin film transistor substrate 21 on which a thin film transistor is formed and a color filter substrate 22 facing the thin film transistor substrate 21. A liquid crystal layer (not shown) is positioned between both substrates 21 and 22. The liquid crystal display panel 20 forms a screen by adjusting the arrangement of the liquid crystal layer, but since the liquid crystal display panel 20 is a non-light emitting device, light must be supplied from the light source unit 50 located on the rear surface. One side of the thin film transistor substrate 21 is provided with a driver 25 for applying a drive signal. The driver 25 includes a flexible printed circuit board (FPC. 26), a driving chip (27) mounted on the flexible printed circuit board (26), and a circuit board (PCB) connected to the other side of the flexible printed circuit board (26). 28). The driver 25 illustrated represents a chip on film (COF) method, and other known methods such as a tape carrier package (TCP) and a chip on glass (COG) may be used. In addition, the driver 25 may be mounted on the thin film transistor substrate 21.

The optical film 30 disposed on the rear surface of the liquid crystal display panel 20 includes a diffusion film 31, a prism film 32, and a protective film 33.

The diffusion film 31 consists of a base plate and a bead-shaped coating layer formed on the base plate. The diffusion film 31 diffuses light from the light source unit 50 and supplies the light to the liquid crystal display panel 20. The diffusion film 31 may be used by overlapping two or three sheets.

The prism film 32 is formed with a triangular prism-shaped prism on the upper surface. The prism film 32 collects light diffused from the diffusion film 31 in a direction perpendicular to the plane of the upper liquid crystal display panel 20. Two prism films 32 are usually used, and the micro prisms formed on the prism films 32 are at an angle. The light passing through the prism film 32 is almost vertically progressed to provide a uniform luminance distribution.

The protection film 33 positioned at the top protects the prism film 32 that is weak to scratches.

The light guide plate 40 is usually made of acrylic resin and serves to uniformly supply the light from the light source unit 50 to the diffusion film 31. The light guide plate 40 is a rectangular plate type and has an exit surface 40a facing the diffusion film 31, a pair of entrance surfaces 40b facing the light source unit 50, and a reflection surface 40c facing the reflecting plate 70. ).

The light source units 50 are positioned along the pair of incident surfaces 40b of the light guide plates facing each other. In the first embodiment, the light source unit 50 includes a light source body 51 as a lamp and electrode portions 52 positioned at both ends of the light source body 51. The light source unit 50 may be a cold cathode fluorescent lamp (CCFL) or an external electrode fluorescent lamp (EEFL).

Meanwhile, in the liquid crystal display device 1 according to another embodiment of the present invention, as shown in FIG. 2B, the prism 43 serving as the optical film 30 of the first embodiment is formed on the plate surface of the light guide plate 40. ) Is integrally formed. Accordingly, the light incident from the light source unit 50 is polarized by the prism 43 of the light guide plate 40 and is incident in a direction perpendicular to the plane of the upper liquid crystal display panel 20.

The reflection plate 60 surrounds the light source unit 50 together with the incident surface 40b of the light guide plate 40 and reflects the light incident from the light source unit 50 toward the light guide plate 40. The reflecting plate 60 has a reflecting protrusion 61 protruding from the plate surface so as to adjust a range in which light emitted from the light source unit 50 is reflected and incident on the light guide plate 40.

The reflector 60 may be provided in parallel with the light guide plate 40 as shown in FIGS. 2A and 2B, or may be provided to be inclined at a predetermined angle inside the light guide plate 40 as shown in FIG. 3B. This is to design the incidence range of the light to be optimal according to the size of the light guide plate 40 and the size of the incident surface 40b.

Here, the reflection protrusion 61 adjusts an incident range of light incident to the light guide plate 40 by adjusting a reflection angle at which light incident from the light source unit 50 is reflected. The reflecting protrusion 61 protrudes from the plate surface of the reflecting plate 60 along the longitudinal direction of the light source unit 51. It is preferable that the plurality of reflecting protrusions 61 are provided with a prism. The reflecting projection 61 spectra the incident light into different ranges according to the wavelength to adjust the incident range of the light incident on the light guide plate 40.

The reflecting protrusion 61 may be formed directly on the surface of the reflecting plate 60 with the same material as the reflecting plate 60 or may be formed in a separate member and then coupled to the reflecting plate 61. Here, the separate member may be used, such as optical glass, rock salt, quartz and the like of a general prism. The reflection protrusion 61 may reflect light at an angle equal to the incident angle or reflect light at a different angle of incidence depending on the shape of the material and the reflective surface.

The shape of the reflective protrusion 61 may be differently provided according to the incident range of light incident on the light guide plate 40, and may be provided in a polygonal shape including a triangle as shown in FIG. 3A. As the shape of the reflecting protrusion 61 becomes polygonal, the number of times the light is reflected increases, thereby adjusting the incident range of light incident on the light guide plate 40.

On the other hand, the reflective projections 61 may be provided in the same shape, or may be provided in different shapes. In the case of the same shape, it may be provided continuously or discontinuously. In addition, even if the shape is the same, as the size is closer to the light guide plate 40, the size can be changed larger or smaller.

3A to 3D are exemplary views showing various embodiments of the reflector plate 60 according to the present invention.

The reflecting plate 60 shown in FIG. 3A is provided in parallel to the light guide plate 40, and the reflecting protrusions 61 are continuously provided at equal intervals in a triangular shape of the same size. The light incident from the light source unit 50 is reflected by hitting the reflecting projection 61 of the reflecting plate 60 as indicated by the solid line. At this time, the light is reflected and the reflection angle is adjusted according to the shape of the projection is reflected and is reflected back by the opposite projection is incident to the light guide plate 40 or directly to the light guide plate 40.

At this time, the incident range of light incident on the light guide plate 40 is about 2.8 degrees. In general, when the incident range of the light incident on the light guide plate 40 exceeds ± 42 °, incident light that cannot be polarized by the light guide plate 40 and the air layer is generated, and thus the light utilization efficiency is lowered. The front luminance of (20) is lowered. Accordingly, since the reflecting plate 60 according to the present invention adjusts the incident range of light incident to the light guide plate 40 to ± 2.8 °, leakage light does not occur, thereby increasing the utilization efficiency of light and increasing the front of the liquid crystal display panel 20. The brightness rises.

The reflecting plate 60 ′ shown in FIG. 3B is provided to be inclined at a predetermined angle to the inside of the light guide plate 40, and triangular reflecting protrusions 61 are continuously provided. In this case, an incident range of light incident on the light guide plate 40 is about ± 21.5 °.

Meanwhile, the reflective plate 60 ′ shown in FIG. 3C is provided to be inclined at a predetermined angle inside the light guide plate 40. In this case, an incident range of light incident on the light guide plate 40 is about 22 °.

On the other hand, the reflective plate 60 shown in Figure 3d is provided as the size of the reflecting projection (61 ') closer to the light guide plate (40). In this case, the height of the reflection protrusion 61 ′ may be provided differently according to the incident range.

4A to 4D show an incident distribution of light incident on the light guide plate 40 from each of the reflecting plates 60 shown in FIGS. 3A to 3C.

First, FIG. 4A shows a range of light incident on the light guide plate 40 in a reflection plate (not shown) without a conventional protrusion. As shown in the figure, the range of light incident from a conventional reflector (not shown) is ± 50 °, and light exceeding ± 42 ° becomes leakage light.

The incidence range of the light reflected from the reflecting plate 60 shown in FIG. 3A is within ± 22.8 ° as shown in FIG. 4B, and the incidence range of the light reflected from the reflecting plate 60 shown in FIG. 3B is shown in FIG. 4C. As described above, it is within ± 21.5 °, and the incident range of light along the reflecting plate 60 shown in FIG. 3C is within ± 22 ° as shown in FIG. 4D.

That is, since the range of light incident from the reflecting plate 60 according to the present invention to the light guide plate 40 is adjusted by the reflecting protrusions 61 and 61 ', the polarized light is not separated by ± 22 ° without leaking light. Since light is reduced and the amount of light incident on the liquid crystal display panel 20 is increased vertically, the light utilization efficiency is increased.

The diffusion plate 70 is positioned under the light guide plate 40 and serves to supply the light guide plate 40 by reflecting light toward the bottom again. The diffusion plate 70 may be made of polyethylene terephthalate (PET) or PC (polycarbonate).

The lower cover member 80 forms an accommodating space for accommodating the light guide plate 40, the light source unit 50, and the reflecting plate 60. The lower cover member 80 may be made of aluminum or galvanized steel sheet.

Although some embodiments of the invention have been shown and described, those skilled in the art will recognize that modifications can be made to the embodiments without departing from the spirit or principles of the invention. . It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

As described above, the liquid crystal display according to the present invention may adjust the incidence range of the light incident on the light guide plate by adjusting the reflection angle of the light incident from the light source unit.

Accordingly, the utilization range of light may be increased by adjusting the incident range of light incident to the light guide plate to within ± 22 ° where leakage light does not occur. In addition, the amount of vertically incident light of the polarized light separated from the LGP increases, so that the front luminance increases.

Claims (12)

A liquid crystal display panel; A light guide plate on a rear surface of the liquid crystal display panel; A light source unit disposed on at least one side of the light guide plate; And a reflecting plate having a plurality of reflecting protrusions to adjust the incidence angle of the reflected light incident on the light guide plate while adjusting the reflecting angle of the light irradiated from the light source unit while surrounding the light source unit. The method of claim 1, And the plurality of reflecting protrusions are provided integrally with the reflecting plate. The method of claim 2, And a plurality of reflecting projections having a polygonal cross section. The method of claim 3, The plurality of reflective projections are provided so that the height is different from each other. The method of claim 4, wherein And the plurality of reflecting protrusions are provided to increase in height as they are closer to the light guide plate. The method according to any one of claims 1 to 5, And the plurality of reflection protrusions are prisms. The method according to any one of claims 1 to 5, And the reflecting plate is provided in parallel with the light guide plate. The method according to any one of claims 1 to 5, And the reflective plate is inclined at a predetermined angle with the light guide plate. A light source unit; And a reflecting plate forming a spaced space with the light source unit and provided in a peripheral area of the light source unit, the reflector having a projection formed to protrude along the spaced space and reflecting light emitted from the light source unit at a predetermined angle. unit. The method of claim 9, The reflector is a backlight unit, characterized in that provided integrally with the reflecting plate. The method of claim 10, The reflector is a backlight unit, characterized in that the cross section is provided in a triangular shape. The method according to any one of claims 9 to 11, The reflector is a backlight unit, characterized in that the prism.

Images