KR20100012415A - Light unit and liquid crystal display device having the same - Google Patents

Abstract

PURPOSE: A light unit and a liquid crystal display device with the same are provided to reduce the amount of light emitted from a light source to penetrate a light guide plate. CONSTITUTION: A light source(120) is arranged under a light guide plate(110). A light guide member(130) is extended from the lower side of the light guide plate(111) toward the light source. The light guide member slopes to the light guide plate. The light source is a line source or a point source of light. An entrance side of the light guide member is parallel to the lower side of the light guide plate. An air layer(160) or a low refractive index layer with refractive index lower than the light guide member is arranged between the light guide plate and the light guide member. A reflection member is arranged to be adjacent to the light guide member.

Description

LIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE SAME}

Embodiments relate to a light unit and a liquid crystal display device.

As information processing technology develops, display devices such as LCD, PDP and AMOLED are widely used.

In particular, LCDs need a backlight unit that generates light, and such backlight units must have high brightness and brightness uniformity.

Embodiments provide a light unit and a liquid crystal display device in which luminance uniformity is improved. In particular, the embodiment is intended to provide a light unit which prevents the luminance of the region of the light guide plate adjacent to the light source from abnormally increasing and reduces the number of light sources used.

The light unit according to the embodiment includes a light guide plate; A light source disposed under the light guide plate; And a light guide member extending from a lower surface of the light guide plate toward the light source and inclined with respect to the light guide plate.

In another embodiment, a light unit includes: a light guide plate; A light source disposed under the light guide plate to generate light; And an optical guide member which receives the light and guides the light toward the lower surface of the light guide plate in a direction inclined to the light guide plate.

In another embodiment, a liquid crystal display device includes a liquid crystal panel; A light guide plate disposed under the liquid crystal panel; A light source disposed under the light guide plate; And a light guide member extending from a lower surface of the light guide plate toward the light source and inclined with respect to the light guide plate.

The light unit according to the embodiment includes a light guide member for guiding the light generated from the light source in a direction inclined to the light guide plate.

Therefore, the light emitted from the light source is incident by the light guide member in a direction inclined to the light guide plate and totally reflected inside the light guide plate.

That is, the light unit according to the embodiment may reduce the amount of light emitted from the light source and directly passing through the light guide plate.

Therefore, in the light unit according to the embodiment, since the light guide plate totally reflects the incident light and emits the light upwardly, luminance uniformity is improved.

In addition, the light unit according to the embodiment may improve luminance uniformity when the light source is disposed under the light guide plate when applied to the liquid crystal display of the large screen.

That is, when applied to a large screen liquid crystal display, the light unit according to the embodiment has higher luminance uniformity than the conventional edge type backlight unit.

Similarly, the liquid crystal display according to the embodiment also has improved luminance uniformity.

In the description of the embodiments, each panel, member, lamp, sheet, or substrate is described as being formed "on" or "under" of each panel, member, lamp, sheet, or substrate. In the case, “on” and “under” include both being formed “directly” or “indirectly” through other components. In addition, the criteria for the top or bottom of each component will be described with reference to the drawings. The size of each component in the drawings may be exaggerated for description, and does not mean a size that is actually applied.

1 is an exploded perspective view illustrating a liquid crystal display according to an embodiment. 2 is a perspective view illustrating a rear surface of the light guide plate and the light guide member. 3 is a cross-sectional view taken along line AA ′ in FIG. 1. 4 is an enlarged cross-sectional view of a portion B in FIG. 3.

1 to 4, the liquid crystal display includes a backlight unit 100 and a liquid crystal panel 200.

The backlight unit 100 generates light and emits the light toward the liquid crystal panel 200. The backlight unit 100 includes a light guide plate 110, a lamp 120, an optical guide member 130, an optical sheet 140, and a case 150.

The light guide plate 110 has a plate shape and emits incident light upward through total reflection, refraction, and scattering. In addition, the light guide plate 110 is transparent.

Alternatively, the light guide plate 110 may be translucent.

Examples of the material used as the light guide plate 110 include polymethyl methacrylate (PMMA), polystyrene (PS), polycarbonate (PC), and the like.

The lamp 120 is disposed under the light guide plate 110. A plurality of lamps 120 are arranged at regular intervals. Generate the light. The lamp 120 may include, for example, a cold cathode fluorescent lamp (CCFL) or an external electrode fluorescent lamp (EEFL).

The light guide member 130 corresponds to the lamp 120 and is attached to the bottom surface 111 of the light guide plate 110. For example, the light guide member 130 is adhered to the lower surface 111 of the light guide plate 110 by a transparent adhesive, a transparent thermosetting resin or a transparent photocuring resin.

The light guide member 130 is transparent, and examples of the material that can be used as the light guide member 130 include polymethyl methacrylate, polystyrene, polycarbonate, and the like.

The optical guide member 130 includes a first optical guide member 131 and a second optical guide member 132. The first light guide member 131 and the second light guide member 132 are symmetrical with each other, and are substantially identical in configuration. In addition, the first light guide member 131 and the second light guide member 132 are connected to each other.

Alternatively, the first light guide member 131 and the second light guide member 132 may be spaced apart from each other at a predetermined interval.

The first light guide member 131 extends from the lower surface 111 of the light guide plate 110 toward the lamp 120. The first light guide member 131 is inclined with respect to the light guide plate 110. In more detail, the light guide plate 110 is inclined with respect to the bottom surface 111.

The first light guide member 131 includes an entrance surface 133, an exit surface 134, a first side surface 135, and a second side surface 136.

The incident surface 133 faces the lamp 120, and the exit surface 134 faces the light guide plate 110. The exit surface 134 is in close contact with or adhered to the bottom surface 111 of the light guide plate 110.

The first side 135 is concave and the second side 136 is convex. That is, the first light guide member 131 is curved with a predetermined curvature.

Alternatively, the first side 135 and the second side 136 may be flat.

An air layer 160 is present between the light guide member 130 and the light guide plate 110. That is, the air layer 160 is present between the second side surface 136 and the lower surface 111 of the light guide plate 110.

The optical sheet 140 is disposed on the light guide plate 110. The optical sheet 140 improves the characteristics of the light passing through. The optical sheet 140 may be a diffusion plate, a lens forming sheet, a polarizing sheet, a diffusion sheet, or a prism sheet.

The case 150 accommodates the light guide plate 110, the light guide member 130, the lamp 120, and the optical sheet 140. In addition, the case 150 accommodates the liquid crystal panel 200.

The backlight unit 100 may include a reflector disposed between the case 150 and the lamp 120 and a lamp guide for fixing the lamp 120.

The liquid crystal panel 200 displays an image by adjusting the intensity of light passing in units of pixels. The liquid crystal panel 200 may include a TFT substrate, a color filter substrate, and a liquid crystal layer interposed between the two substrates.

The light guide member 130 receives light emitted from the lamp 120 and guides the light guide plate 110 to the light guide plate 110. That is, light emitted from the lamp 120 toward the first light guide member 131 is incident through the incident surface 133.

The incident light is totally reflected inside the first light guide member 131 and is emitted through the emission surface 134. The emitted light is incident on the light guide plate 110 through the bottom surface 111 of the light guide plate 110.

That is, since the air layer 160 exists between the second side surface 136 and the bottom surface 111 of the light guide plate 110, the incident light does not emit light through the second side surface 136. , Total reflection.

Alternatively, a material having a lower refractive index than the light guide member 130 may be filled between the second side surface 136 and the lower surface 111 of the light guide plate 110.

Since the first light guide member 131 is inclined with respect to the light guide plate 110, the emitted light is incident to the light guide plate 110 in an inclined direction. That is, most of the light emitted from the light source is guided upward or laterally by the first light guide member 131 and is incident on the light guide plate 110.

Similarly, the second light guide member 132 guides most of the light emitted from the lamp 120 upwardly or laterally to enter the light guide plate 110.

Since most of the light emitted from the lamp 120 is guided upwards or laterally to be incident on the light guide plate 110, the light incident on the light guide plate 110 is totally reflected inside the light guide plate 110.

In particular, most of the light emitted upward from the lamp 120 is guided laterally or upwardly by the light guide member 130 and is incident on the light guide plate 110. Thus, the amount of light emitted upward from the lamp 120 and directly passing through the light guide plate 110 is reduced. That is, the liquid crystal display according to the embodiment may prevent the phenomenon in which the luminance of the region corresponding to the lamp 120 rises abnormally.

Thus, the backlight unit 100 has improved luminance uniformity, and the liquid crystal display according to the embodiment has improved luminance uniformity and improved image quality.

In addition, since the lamp 120 is disposed under the light guide plate 110, as the area of the light guide plate 110 and the liquid crystal panel 200 increases, the number of the lamps 120 may increase. have.

That is, in the case of the conventional edge type liquid crystal display, the position of the lamp is limited, so that the luminance uniformity decreases as the area of the screen increases.

However, in the LCD according to the exemplary embodiment, as the area of the screen increases, the lamp 120 may be disposed at a desired position.

Therefore, the liquid crystal display according to the exemplary embodiment is not limited to the areas of the light guide plate 110 and the liquid crystal panel 200, and may maintain luminance uniformity even on a large screen.

In addition, as compared with the conventional direct type, the liquid crystal display according to the embodiment is provided between the lamp 120 and the light guide plate 110 to secure the uniformity of luminance by the light guide member 130. The gap can be reduced.

Therefore, the liquid crystal display according to the embodiment can be formed slim.

5A and 5B are cross-sectional views illustrating a lamp and a light guide member according to another embodiment. In this embodiment, with reference to the above-described embodiment, the incident surface, the scattering pattern and the reflective sheet will be further described.

5A and 5B, the first light guide member 131 includes incident surfaces 139a and 139b which are curved surfaces. The incident surface 139a may have a concave or curved plane. The incident surface 139a corresponds to the outer circumferential surface of the lamp 120. In addition, the incident surface 139 surrounds part or all of the outer circumferential surface of the lamp 120.

Alternatively, the incident surface 139b may have a convex or curved plane.

In addition, the scattering pattern 137 is formed on a part of the first side surface 135. The scattering pattern 137 may have a surface roughness capable of scattering light, or may have a concave or convex shape. The shape, size, and area of the formed region of the scattering pattern 137 may be adjusted in various ranges.

In addition, the reflective sheet 164 may be disposed under the light guide plate 110. The reflective sheet 164 includes a reflective layer 165 for reflecting light and a support 166 supporting the reflective layer 165. The reflective layer 165 has a curved surface corresponding to the lamp 120.

The incident surfaces 139a and 139b are curved surfaces, and in particular, since the incident surfaces 139a of FIG. 5A correspond to the outer circumferential surface of the lamp 120, more light may be incident. In addition, a lot of light is guided laterally or upwardly by the first light guide member 131 and totally reflected inside the light guide plate 110.

In addition, the light generated from the lamp 120 is reflected upward by the reflective sheet 164. In particular, since the reflective sheet 164 has a curved surface corresponding to the lamp 120, the light generated by the lamp 120 may be efficiently focused toward the incident surfaces 139a and 139b.

That is, the curved surface of the reflective sheet 164 corresponding to the lamp 120 performs a light collecting unit function to collect the light emitted from the lamp 120 and reflect upward.

Therefore, in the liquid crystal display according to the present exemplary embodiment, more light may be incident on the light guide plate 110 through the light guide members 131 and 132.

Thus, the liquid crystal display according to the present embodiment has improved luminance and luminance uniformity.

In addition, the luminance of the region corresponding to the emission surface 134 may be adjusted by the scattering pattern 137. That is, the scattering pattern 137 prevents the luminance of the region corresponding to the emission surface 134 from decreasing.

Thus, the liquid crystal display according to the present embodiment has improved luminance uniformity.

In addition, the reflective sheet 164 of the present embodiment is applicable to other embodiments.

6 is a cross-sectional view illustrating a lamp and a light guide member according to still another embodiment. In the present embodiment, with reference to the above-described embodiments, the third optical guide member and the adhesive member will be further described.

Referring to FIG. 6, the light guide member 130 includes a third light guide member 138 interposed between the first light guide member 131 and the second light guide member 132. In this case, the first to third light guide members 131, 132, and 138 are integrally formed.

The third light guide member 138 receives light emitted from the lamp 120 and exits upward. The third light guide member 138 includes a third entrance surface 138a and a third exit surface 138b.

The third incident surface 138a is parallel to the bottom surface 111 of the light guide plate 110. The third emission surface 138b is parallel to the bottom surface 111 of the light guide plate 110.

Alternatively, the third entrance surface 138a and the third exit surface 138b may be convex or concave.

In addition, the light guide member 130 is bonded to the light guide plate 110 by a transparent adhesive member 190. Therefore, even if the emission surface 134 of the light guide member 130 is uneven or a predetermined pattern is formed, the adhesive member 190 is flattened.

Therefore, in order to improve the characteristics of the light emitted to the exit surface 134 of the light guide member 130, a predetermined pattern may be formed. In this case, the adhesive member 190 may efficiently enter the light emitted from the light guide member 130 to the light guide plate 110.

In addition, a part of the light emitted upward from the lamp 120 is incident on the third incident surface 138a and is emitted through the third emission surface 138b. The emitted light passes through the light guide plate 110 and is incident on the liquid crystal panel 200.

In the liquid crystal display according to the present exemplary embodiment, the area of the third incident surface 138a may be adjusted to adjust the amount of light directly passing through the light guide plate 110 upward.

Accordingly, the liquid crystal display according to the present exemplary embodiment can prevent a phenomenon in which the luminance of the region corresponding to the air layer 160 is lower than that of other regions, and can improve the luminance uniformity.

7 is a cross-sectional view illustrating a lamp and a light guide member according to still another embodiment. In this embodiment, with reference to the above-described embodiments, the reflective member will be further described.

Referring to FIG. 7, the liquid crystal display includes a first reflecting member 171 and a second reflecting member 172.

The first reflecting member 171 is disposed on the first side surface 135. In more detail, the first reflective member 171 is attached to the first side surface 135.

The second reflecting member 172 is disposed on the second side surface 136. In more detail, the second reflecting member 172 is attached to the second side surface 136.

The first reflecting member 171 and the second reflecting member 172 reflect light incident on the light guide member 130. Examples of the material used as the first reflecting member 171 and the second reflecting member 172 include metal or white paint.

In the present exemplary embodiment, both the first reflective member 171 and the second reflective member 172 are used. Alternatively, the liquid crystal display according to the exemplary embodiment may include the first reflective member 171 and the second reflective member. Only one of the members 172 may be included.

A portion of the light emitted from the lamp 120 and incident on the light guide member 130 may be emitted through the first side surface 135 and the second side surface 136.

In this case, since the first reflecting member 171 and the second reflecting member 172 reflect the emitted light and enter the light guide member 130 again, the light guide member 130 efficiently enters the incident light. Can guide.

Thus, the liquid crystal display according to the embodiment has improved luminance uniformity.

8 is a cross-sectional view illustrating a lamp and a light guide member according to still another embodiment. In the present embodiment, the first scattering pattern and the second scattering pattern will be further described with reference to the above-described embodiments.

Referring to FIG. 8, first and second scattering patterns 112 and 113 are formed on the bottom surface 111 of the light guide plate 110. The first scattering pattern 112 is formed in the region LB corresponding to the air layer 160, and the second scattering pattern 113 is formed in the region HB between the light guide members.

Therefore, the first scattering pattern 112 may compensate that the luminance of the region LB corresponding to the air layer 160 is lowered.

Thus, the liquid crystal display according to the present embodiment has improved luminance uniformity.

9 is an exploded perspective view illustrating a liquid crystal display according to another exemplary embodiment. 10 is a perspective view illustrating a rear surface of a light guide plate and a light guide member according to still another embodiment. 11 is a cross-sectional view illustrating a cross section of a liquid crystal display according to another exemplary embodiment. FIG. 12 is an enlarged cross-sectional view of part C in FIG. 11. In the present embodiment, the light emitting diode and the light guide member will be further described with reference to the above-described embodiments.

9 to 12, the liquid crystal display includes a light emitting diode 121 and an optical guide member 180.

The light emitting diodes 121 generate light and are disposed under the light guide plate 110. The light emitting diodes 121 are mounted on the printed circuit board 122 to receive a driving signal through the printed circuit board 122.

The light guide member 180 corresponds to the light emitting diode 121 and is adhered or adhered to the light guide plate 110.

The light guide member 180 extends from the bottom surface 111 of the light guide plate 110 toward the light emitting diode 121. In this case, the light guide member 180 is inclined with respect to the bottom surface 111 of the light guide plate 110.

That is, the light guide member 180 has a cone-shaped shape from which the inside is removed.

Accordingly, the light guide member 180 has an incident surface 182, an exit surface 183, an outer circumferential surface 184, and an inner circumferential surface 185. In this case, an air layer 160 is formed between the inner circumferential surface 185 and the lower surface 111 of the light guide plate 110.

The liquid crystal display according to the present exemplary embodiment uses the light emitting diode 121 as a point light source and may have improved luminance uniformity.

In addition, the liquid crystal display according to the present exemplary embodiment includes the scattering pattern, the reflective sheet, the adhesive member, the third light guide member, the first and second reflective members, and the first and second described in the embodiments of FIGS. 5A to 8. It may include components such as a second scattering pattern.

For example, a reflective member and a scattering pattern may be formed on the outer circumferential surface 184 and / or the inner circumferential surface 185, and a reflective sheet having a light collecting function may be disposed below the light guide plate 110. In addition, a predetermined pattern is formed on the emission surface 183, and the light guide plate 110 and the light guide member 180 may be bonded by an adhesive member. In addition, the incident surface 182 may be a concave, convex, or curved plane. In addition, the light guide member 180 may have an entrance surface and an exit surface parallel to the bottom surface of the light guide plate.

Although the above description has been made based on the embodiments, these are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains may not have been exemplified above without departing from the essential characteristics of the present embodiments. It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 is an exploded perspective view illustrating a liquid crystal display according to an embodiment.

2 is a perspective view illustrating a rear surface of the light guide plate and the light guide member.

3 is a cross-sectional view taken along line AA ′ in FIG. 1.

4 is an enlarged cross-sectional view of a portion B in FIG. 3.

5A and 5B are cross-sectional views illustrating lamps and light guide members according to other embodiments.

6 is a cross-sectional view illustrating a lamp and a light guide member according to still another embodiment.

7 is a cross-sectional view illustrating a lamp and a light guide member according to still another embodiment.

8 is a cross-sectional view illustrating a lamp and a light guide member according to still another embodiment.

9 is an exploded perspective view illustrating a liquid crystal display according to another exemplary embodiment.

10 is a perspective view illustrating a rear surface of a light guide plate and a light guide member according to still another embodiment.

11 is a cross-sectional view illustrating a cross section of a liquid crystal display according to another exemplary embodiment.

FIG. 12 is an enlarged cross-sectional view of part C in FIG. 11.

Claims (17)

Light guide plate; A light source disposed under the light guide plate; And And a light guide member extending from a lower surface of the light guide plate toward the light source and inclined with respect to the light guide plate. The light unit of claim 1, wherein the light source is a line light source or a point light source. The light unit of claim 1, wherein the light guide member comprises an incident surface parallel to a bottom surface of the light guide plate. The light unit of claim 1, wherein an air layer or a low refractive index layer having a lower refractive index than that of the light guide member is disposed between the light guide plate and the light guide member. The light unit of claim 1, further comprising a reflecting member disposed adjacent to the light guide member. The light unit of claim 1, further comprising a scattering pattern formed on a side surface of the light guide member. The light unit of claim 1, wherein the light guide plate and the light guide member are integrally formed. Light guide plate; A light source disposed under the light guide plate to generate light; And And a light guide member which receives the light and guides the light toward the lower surface of the light guide plate in a direction inclined to the light guide plate. The method of claim 8, further comprising an adhesive member interposed between the light guide member and the light guide plate, The light guide member is integrally formed with the light guide plate. The light unit of claim 8, wherein an air layer exists between the light guide member and the light guide plate. The light unit of claim 8, further comprising an optical sheet disposed on the light guide plate. A liquid crystal panel; A light guide plate disposed under the liquid crystal panel; A light source disposed under the light guide plate; And And a light guide member extending from a lower surface of the light guide plate toward the light source and inclined with respect to the light guide plate. The liquid crystal display of claim 12, wherein the light source generates light, and the light guide member guides the light toward a lower surface of the light guide plate. The liquid crystal display device of claim 12, further comprising a reflective sheet disposed under the light guide plate and having a curved surface. The liquid crystal display of claim 12, wherein an air layer is present between the light guide member and the lower surface of the light guide plate. The liquid crystal display of claim 12, wherein the light guide member comprises a concave, convex, or curved incidence surface corresponding to the light source. The method of claim 12, further comprising an adhesive member interposed between the light guide member and the light guide plate, And the optical guide member is integrally formed with the light guide plate.

Images