Backlight apparatus, light guide plate, and display apparatus applying the same

CROSS-REFERENCE TO RELATED APPLICATIONS

p-0002This application claims priority from Korean Patent Application No. 10-2009-0057567, filed on Jun. 26, 2009 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

p-00031. Field

p-0004Apparatuses and methods consistent with the inventive concept relate to a backlight apparatus, a light guide plate, and a display apparatus applying the same, and more particularly, to a backlight apparatus that provides local dimming, a light guide plate, and a display apparatus applying the same.

p-00052. Description of the Related Art

p-0006As technology for light emitting diodes (LEDs) develops, fields using LEDs increase. In particular, since LEDs are used as backlight for display apparatuses, the thickness of display apparatuses can be innovatively thin.

p-0007In order to make display apparatuses slim using LEDs, edge-type backlight in which an LED backlight is disposed on the edge of a display is used.

p-0008However, edge-type backlight has difficulty in providing local dimming. In a related art, in order to provide local dimming using edge-type backlight, a light guide plate is divided so as to dispose LEDs on sides of the light guide plate, or a light guide plate is partitioned into multiple light guide plates so as to dispose LEDs between light guide plates. However, in these methods, the quality of image does not become uniform due to division or partition of the light guide plate.

p-0009A user desires a display apparatus of uniform and good image quality, so there is a need for providing a backlight apparatus capable of displaying images of uniform image quality.

SUMMARY

p-0010Exemplary embodiments address at least the above problems and/or disadvantages and other disadvantages not described above. Also, the exemplary embodiments are not required to overcome the disadvantages described above, and an exemplary embodiment may not overcome any of the problems described above.

p-0011One or more exemplary embodiments provide a backlight apparatus including a light guide plate on which a plurality of grooves having a linear shape are formed to cut off movement of light, a light emitting unit to emit light onto the light guide plate, and a display apparatus applying the same.

p-0012According to an exemplary embodiment, there is provided a backlight apparatus including a light guide plate (LGP) on which a plurality of grooves of a linear shape are formed to cut off movement of light, and a light emitting unit which emits the light onto the LGP.

p-0013The LGP may be optically divided into a plurality of areas by the grooves.

p-0014The light emitting unit may include a plurality of light emitting modules which are disposed to correspond to the plurality of areas of the LGP.

p-0015In order to support local dimming, the light emitting unit may operate the plurality of light emitting modules separately based on an input image signal so as to adjust an amount of the light emitted onto each of the plurality of areas.

p-0016The grooves of the linear shape may be grooves of a dotted-line shape or grooves of a solid-line shape.

p-0017The light emitting unit may emit the light toward a side of the LGP.

p-0018The light emitting unit may be disposed along two sides of the LGP which face each other, and the LGP may have the plurality of grooves of the linear shape which are formed perpendicular to the light emitting unit.

p-0019The LGP may have one more groove of the linear shape which is formed parallel to the light emitting unit.

p-0020Intervals between the plurality of grooves on the LGP may be unequal.

p-0021Intervals between the plurality of grooves on the LGP may be increasingly wide toward a center of the LGP.

p-0022The light emitting unit may include at least one point light source.

p-0023The point light source may be an LED.

p-0024According to another exemplary embodiment, there is provided a display apparatus including a backlight apparatus as described above.

p-0025According to yet another exemplary embodiment, there is provided an LGP which is included in a backlight apparatus as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0026The above and/or other aspects of the inventive concept will be more apparent by describing certain exemplary embodiments with reference to the accompanying drawings, in which:

p-0027<figref idrefs="DRAWINGS">FIG. 1</figref> is a perspective view of a backlight apparatus according to an exemplary embodiment;

p-0028<figref idrefs="DRAWINGS">FIG. 2</figref> is a plane view of a backlight apparatus according to an exemplary embodiment;

p-0029<figref idrefs="DRAWINGS">FIG. 3</figref> is a front view of a light guide plate having grooves of a linear shape according to an exemplary embodiment;

p-0030<figref idrefs="DRAWINGS">FIG. 4A</figref> is a side view of a light guide plate having grooves of a discontinuous linear shape according to an exemplary embodiment;

p-0031<figref idrefs="DRAWINGS">FIG. 4B</figref> is a side view of a light guide plate having grooves of a continuous linear shape according to an exemplary embodiment;

p-0032<figref idrefs="DRAWINGS">FIG. 5A</figref> illustrates a light guide plate which is optically divided into 8 areas by grooves of a discontinuous linear shape according to an exemplary embodiment;

p-0033<figref idrefs="DRAWINGS">FIG. 5B</figref> illustrates a light guide plate which is optically divided into 16 areas by grooves of a discontinuous linear shape according to an exemplary embodiment;

p-0034<figref idrefs="DRAWINGS">FIG. 6A</figref> illustrates a light guide plate which is optically divided into 8 areas by grooves of a continuous linear shape according to an exemplary embodiment;

p-0035<figref idrefs="DRAWINGS">FIG. 6B</figref> illustrates a light guide plate which is optically divided into 16 areas by grooves of a continuous linear shape according to an exemplary embodiment;

p-0036<figref idrefs="DRAWINGS">FIG. 7A</figref> illustrates a light guide plate which is optically divided into 8 areas by grooves having unequal intervals and a discontinuous linear shape according to an exemplary embodiment;

p-0037<figref idrefs="DRAWINGS">FIG. 7B</figref> illustrates a light guide plate which is optically divided into 16 areas by grooves having unequal intervals and a discontinuous linear shape according to an exemplary embodiment;

p-0038<figref idrefs="DRAWINGS">FIG. 8A</figref> illustrates a light guide plate which is optically divided into 8 areas by grooves having unequal intervals and a continuous linear shape according to an exemplary embodiment;

p-0039<figref idrefs="DRAWINGS">FIG. 8B</figref> illustrates a light guide plate which is optically divided into 16 areas by grooves having unequal intervals and a continuous linear shape according to an exemplary embodiment;

p-0040<figref idrefs="DRAWINGS">FIG. 9A</figref> illustrates a light guide plate on which one more groove of a discontinuous linear shape is formed at the center parallel to a light emitting unit according to an exemplary embodiment; and

p-0041<figref idrefs="DRAWINGS">FIG. 9B</figref> illustrates a light guide plate on which one more groove of a continuous linear shape is formed at the center parallel to a light emitting unit according to an exemplary embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

p-0042Certain exemplary embodiments will now be described in greater detail with reference to the accompanying drawings.

p-0043In the following description, like drawing reference numerals are used for like elements, even in different drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of the invention. However, the exemplary embodiments can be practiced without those specifically defined matters. Also, well-known functions or constructions are not described in detail since they would obscure the exemplary embodiments with unnecessary detail.

p-0044<figref idrefs="DRAWINGS">FIG. 1</figref> is a perspective view of a backlight apparatus according to an exemplary embodiment. As illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref>, the backlight apparatus may include a light guide plate (LGP) <b>100</b>, a light emitting unit <b>110</b>, a diffusion plate <b>120</b>, and an optical sheet <b>130</b>.

p-0045The LGP <b>100</b> performs diffused reflection of light incident from a side of the LGP <b>100</b> so as to form a surface light source. The LGP <b>100</b> uniformly diffuses the light incident on a side of the LGP <b>100</b> so as to illuminate light having a uniform luminance to a panel. More specifically, the LGP <b>100</b> includes a geometrical pattern which is printed or formed on a bottom surface of the LGP <b>100</b> so as to perform diffused reflection of incident light, so the incident light can be reflected with a uniform luminance.

p-0046In addition, the LGP <b>100</b> includes a plurality of grooves <b>200</b> having a linear shape so as to block movement of light. The grooves <b>200</b> are formed lengthwise on a bottom surface of the LGP <b>100</b>. That is, the plurality of grooves <b>200</b> having a linear shape are formed on the LGP <b>100</b> perpendicular to the light emitting unit <b>110</b>.

p-0047The grooves <b>200</b> block movement of light, so the LGP <b>100</b> has a plurality of optically separate areas. The plurality of optically separate areas independently diffuse light to another area thereby providing individual areas for local dimming. Local dimming is a method for illuminating backlight of a different luminance on areas of the screen based on information regarding a luminance of an image signal. The shape of the grooves <b>200</b> of the LGP <b>100</b> is described below with reference to <figref idrefs="DRAWINGS">FIGS. 2 to 8B</figref>.

p-0048The light emitting unit <b>110</b> illuminates light from a side of the LGP <b>100</b> into the LGP <b>100</b>. <figref idrefs="DRAWINGS">FIG. 1</figref> shows that the light emitting unit <b>110</b> illuminates light into the LGP <b>100</b> in the second direction. The light emitting unit <b>110</b> is disposed on two sides, which face each other, of the LGP <b>100</b>. For example, <figref idrefs="DRAWINGS">FIG. 1</figref> shows that light emitting modules of the light emitting unit <b>110</b> are disposed along two opposite sides of the LGP <b>100</b>, which face each other in the second direction.

p-0049As described above, backlight such as the light emitting unit <b>110</b> which illuminates light from a side of the LGP <b>100</b> is called edge-type backlight. A point light source is used as a light source of the edge-type backlight. More specifically, an LED light source is used as a light source of the edge-type backlight. However, the light emitting unit <b>110</b> is not limited with regard to the type of light source that may be used.

p-0050The light emitting unit <b>110</b> includes a plurality of light emitting modules which are disposed to correspond to the plurality of areas formed by the grooves on the LGP <b>100</b>, respectively. That is, the light emitting unit <b>110</b> includes the light emitting modules, which illuminate light to corresponding areas of the LGP <b>100</b>. Each light emitting module includes at least one light source, and independently performs a light emitting operation using a driving circuit. That is, the light emitting unit <b>110</b> independently operates each light emitting module so that light can be selectively illuminated to certain areas of the LGP <b>100</b> based on an input image signal. As a result, the light emitting unit <b>110</b> can support local dimming.

p-0051The diffusion plate <b>120</b> diffuses backlight to widen a field of vision. In addition, the diffusion plate <b>120</b> can focus backlight on a relatively dark area. Therefore, the diffusion plate <b>120</b> can uniformly distribute backlight. The diffusion plate <b>120</b> may be implemented with a lenticular lens sheet in which a plurality of cylindrical lenses are arranged in a row.

p-0052The optical sheet <b>130</b> gives diverse optical effects to backlight. For example, the optical sheet <b>130</b> focuses a polarizing direction of backlight on a particular direction.

p-0053As described above, the backlight apparatus includes the LGP <b>100</b> which is optically divided by the plurality of grooves.

p-0054Hereinafter, the configuration of the LGP <b>100</b> viewed in the first, second, and third directions is described with reference to <figref idrefs="DRAWINGS">FIGS. 2 to 4B</figref>. <figref idrefs="DRAWINGS">FIG. 2</figref> is a plane view of the backlight apparatus according to an exemplary embodiment. More specifically, <figref idrefs="DRAWINGS">FIG. 2</figref> illustrates the shape of the LGP <b>100</b> viewed in the first direction in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0055As illustrated in <figref idrefs="DRAWINGS">FIG. 2</figref>, the LGP <b>100</b> is optically divided into eight areas <b>101</b>-<b>108</b> by seven grooves <b>201</b>-<b>207</b> of a linear shape. The light emitting unit <b>110</b> includes eight upper light emitting modules <b>111</b>-<b>118</b>, and eight lower light emitting modules <b>151</b>-<b>158</b>.

p-0056The first upper light emitting module <b>111</b> and the first lower light emitting module <b>151</b> emit light to the first area <b>101</b>. The second to eighth upper light emitting modules <b>112</b>-<b>118</b> and the second to eighth lower light emitting modules <b>152</b>-<b>158</b> emit light to the second to eighth areas <b>102</b>-<b>108</b>, respectively.

p-0057Since the LGP <b>100</b> is optically divided into the first to eighth areas <b>101</b>-<b>108</b>, the first to eighth areas <b>101</b>-<b>108</b> each receive light from different light emitting modules. Therefore, the backlight apparatus can provide local dimming by designating any of the first to eighth areas <b>101</b>-<b>108</b> as the unit of local dimming. That is, the backlight apparatus can emit different luminance for each area of the LGP <b>100</b> according to information regarding luminance contained in an input image signal, so local dimming can be accomplished using to the first to eighth areas <b>101</b>-<b>108</b>.

p-0058For example, in the case of an image having a bright center and a dark edge, the backlight apparatus may illuminate only the third to sixth upper light emitting modules <b>113</b>-<b>116</b> and the third to sixth lower light emitting modules <b>153</b>-<b>156</b> which correspond to the third to sixth areas <b>103</b>-<b>106</b>, respectively.

p-0059As described above, the backlight apparatus includes the LGP <b>100</b> which is optically divided by the plurality of grooves having a linear shape, so the edge-type backlight can provide local dimming.

p-0060<figref idrefs="DRAWINGS">FIG. 3</figref> is a front view of the LGP <b>100</b> having grooves of a linear shape according to an exemplary embodiment. That is, <figref idrefs="DRAWINGS">FIG. 3</figref> illustrates the shape of the LGP <b>100</b> viewed in the second direction in <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0061As illustrated in <figref idrefs="DRAWINGS">FIG. 3</figref>, seven grooves <b>201</b>-<b>207</b> are formed on the LGP <b>100</b>. According to an exemplary embodiment, the seven grooves <b>201</b>-<b>207</b> may have a uniform width and height. As the width and height of the seven grooves <b>201</b>-<b>207</b> increases, more light can be prevented from illuminating other areas of the LGP. However, if the width and height of the seven grooves <b>201</b>-<b>207</b> are large, light becomes weak at portions of the LGP on which the seven grooves <b>201</b>-<b>207</b> are formed, so the luminance of the backlight may not be uniform. Accordingly, the width and height of the seven grooves <b>201</b>-<b>207</b> may be appropriately set to cut off light and maintain uniform luminance.

p-0062<figref idrefs="DRAWINGS">FIG. 4A</figref> is a side view of the LGP <b>100</b> having grooves of a discontinuous linear shape according to an exemplary embodiment. That is, <figref idrefs="DRAWINGS">FIG. 4A</figref> illustrates the shape of the LGP <b>100</b> viewed in the third direction in <figref idrefs="DRAWINGS">FIG. 1</figref>. In <figref idrefs="DRAWINGS">FIG. 4A</figref>, each groove <b>200</b> includes a plurality of grooves <b>200</b>A-<b>200</b>H formed at regular intervals, as denoted by the dotted-lines, in a line extending across the LGP <b>100</b> in the second direction.

p-0063<figref idrefs="DRAWINGS">FIG. 4B</figref> is a side view of the LGP <b>100</b> having grooves of a continuous linear shape according to an exemplary embodiment. In <figref idrefs="DRAWINGS">FIG. 4B</figref>, each of the grooves <b>200</b> is formed as a single continuous groove extending across the LGP <b>100</b> in the second direction, as denoted by a solid line.

p-0064The shapes of the LGP <b>100</b> having the plurality of grooves have been described in detail so far with reference to <figref idrefs="DRAWINGS">FIGS. 2 to 4B</figref>. Using the LGP <b>100</b>, the backlight apparatus can provide local dimming in the optically divided areas of the LGP <b>100</b>. Therefore, edge-type backlight apparatuses can provide local dimming using the LGP <b>100</b> having a low cost and simple assembly.

p-0065Hereinafter, the LGP <b>100</b> having grooves of different shapes and arranged in different configurations is described with reference to <figref idrefs="DRAWINGS">FIGS. 5A to 9B</figref>.

p-0066<figref idrefs="DRAWINGS">FIG. 5A</figref> illustrates an LGP <b>100</b> which is optically divided into eight areas by seven grooves <b>201</b>-<b>207</b> of a discontinuous linear shape according to an exemplary embodiment. Using such an LGP <b>100</b>, the backlight apparatus can provide local dimming in the eight areas.

p-0067<figref idrefs="DRAWINGS">FIG. 5B</figref> illustrates an LGP <b>100</b> which is optically divided into 16 areas by 15 grooves <b>201</b>-<b>215</b> of a discontinuous linear shape according to an exemplary embodiment. Using such an LGP <b>100</b>, the backlight apparatus can support local dimming in the 16 areas.

p-0068<figref idrefs="DRAWINGS">FIGS. 5A and 5B</figref> illustrate the LGPs <b>100</b> having grooves of a discontinuous linear shape. However, the LGPs may have grooves of a continuous linear shape as in <figref idrefs="DRAWINGS">FIGS. 6A and 6B</figref>.

p-0069<figref idrefs="DRAWINGS">FIG. 6A</figref> illustrates an LGP <b>100</b> which is optically divided into eight areas by grooves <b>201</b>′-<b>207</b>′ of a continuous linear shape according to an exemplary embodiment. Using such an LGP <b>100</b>, the backlight apparatus can support local dimming in the eight areas.

p-0070<figref idrefs="DRAWINGS">FIG. 6B</figref> illustrates an LGP <b>100</b> which is optically divided into 16 areas by grooves <b>201</b>′-<b>215</b>′ of a continuous linear shape according to an exemplary embodiment. Using such an LGP <b>100</b>, the backlight apparatus can support local dimming in the 16 areas.

p-0071In <figref idrefs="DRAWINGS">FIGS. 5A to 6B</figref>, the plurality of grooves on the LGP <b>100</b> are disposed at equal intervals in the third direction, but the plurality of grooves may be disposed at unequal intervals in the third direction. The latter case is described with reference to <figref idrefs="DRAWINGS">FIGS. 7A to 8B</figref>.

p-0072<figref idrefs="DRAWINGS">FIG. 7A</figref> illustrates an LGP <b>100</b> which is optically divided into eight areas by grooves <b>201</b>-<b>207</b> having unequal intervals and a discontinuous linear shape according to an exemplary embodiment. As illustrated in <figref idrefs="DRAWINGS">FIG. 7A</figref>, intervals between the plurality of grooves <b>201</b>-<b>207</b> on the LGP <b>100</b> are different. More specifically, intervals between the plurality of grooves <b>201</b>-<b>207</b> become increasingly wide towards the center of the LGP <b>100</b>.

p-0073<figref idrefs="DRAWINGS">FIG. 7B</figref> illustrates an LGP <b>100</b> which is optically divided into 16 areas by grooves <b>201</b>-<b>215</b> having unequal intervals and a discontinuous linear shape according to an exemplary embodiment. <figref idrefs="DRAWINGS">FIG. 8A</figref> illustrates an LGP <b>100</b> which is optically divided into eight areas by grooves <b>201</b>′-<b>207</b>′ having unequal intervals and a continuous linear shape according to an exemplary embodiment. <figref idrefs="DRAWINGS">FIG. 8B</figref> illustrates an LGP <b>100</b> which is optically divided into 16 areas by grooves <b>201</b>′-<b>215</b>′ having unequal intervals and a continuous linear shape according to an exemplary embodiment. Also, in <figref idrefs="DRAWINGS">FIGS. 7B</figref>, <b>8</b>A and <b>8</b>B, intervals between the plurality of grooves become increasingly wide towards the center of the LGP <b>100</b>.

p-0074If intervals between the plurality of grooves are unequal, uniformity of luminance on the center and edge of the screen can be enhanced.

p-0075<figref idrefs="DRAWINGS">FIG. 9A</figref> illustrates an LGP <b>100</b> on which an additional groove of a discontinuous linear shape is formed at the center of LGP <b>100</b> and parallel to the light emitting unit <b>110</b> according to an exemplary embodiment. As illustrated in <figref idrefs="DRAWINGS">FIG. 9A</figref>, a groove <b>910</b> is formed horizontally at the center of the LGP <b>100</b>. Accordingly, the LGP <b>100</b> is divided into 16 areas, and the backlight apparatus can support local dimming using the 16 areas.

p-0076<figref idrefs="DRAWINGS">FIG. 9B</figref> illustrates an LGP <b>100</b> on which an additional groove of a continuous linear shape is formed at the center of LGP <b>100</b> and parallel to the light emitting unit <b>110</b> according to an exemplary embodiment. As illustrated in <figref idrefs="DRAWINGS">FIG. 9B</figref>, a groove <b>920</b> is formed horizontally at the center of the LGP <b>100</b>. Accordingly, the LGP <b>100</b> is divided into 16 areas, and the backlight apparatus can support local dimming using the 16 areas.

p-0077The edge-type backlight apparatus capable of providing local dimming using the single LGP <b>100</b> which is optically divided has been described in detail. If local dimming is provided using the single optically divided LGP <b>100</b> as described above, the process of manufacture can be simplified and manufacture costs can be saved compared with using an LGP which is physically divided. In addition, if the single optically divided LGP <b>100</b> is used, the number of required LEDs decreases, so the price of the backlight apparatus can be reduced.

p-0078The edge-type backlight apparatus in the above exemplary embodiments can be applied as a backlight apparatus for a display apparatus. More specifically, the backlight apparatus according to the above exemplary embodiments can be applied as a backlight apparatus for an LCD display apparatus.

p-0079As can be appreciated from the above description, a backlight apparatus including an LGP on which a plurality of grooves having a linear shape are formed to cut off movement of light, and a light emitting unit to emit light onto the LGP, and a display apparatus applying the same are provided, so the edge-type backlight apparatus can support local dimming using the single optically divided LGP.

p-0080The foregoing exemplary embodiments are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. Also, the description of the exemplary embodiments is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art.