Patent Description:
A three-dimensional (3D) display may be implemented by representing images of different viewpoints to a left eye and a right eye of a viewer. The 3D display may be a glasses type or a glassless type display. The 3D display of the glassless type may dividedly represent a 3D image based on a viewpoint and dividedly represent an image in a space using an optical control device. The optical control device may include a lenticular lens and a parallax barrier. The lenticular lens may allow each pixel image to be displayed in a predetermined direction. The parallax barrier may allow a predetermined pixel to be shown from a predetermined direction through a slit. To be able to supply the 3D display to a wide range of consumers, the 3D display may be provided with a two-dimensional (2D) display in one device.

In a related art 3D display device provided with a two-dimensional (2D) display, an LED light source may be disposed in a backlight form on a lower portion of a Light Guide Plate (LGP), and when the 2D display is implemented light from the LED light source passes through an LGP layer for implementing a 3D display. Therefore, a dual LGP (or dual BLU and dual backlight unit) in the related art may cause a decrease in brightness and quality of the display compared to a device for implementing the 2D display only. In addition, in the related art 3D display, a gap between an image panel and a barrier pattern (the diffusion pattern disposed in straight line form on the lower portion of the LGP for the 3D mode) is formed such that a direction of light output from the LGP and a position of a corresponding pixel are maintained with respect to an entire area of a panel. However, the gap between the image panel and the barrier pattern may be not uniform and may have a change value with respect to the entire area of the panel due to a manufacturing error or an assembly error. The gap between the image panel and the barrier pattern is more severely changed due to contraction or expansion of the LGP based on the use temperature of the display device or deformation caused by the expansion of the LGP due to heat generated while the display device.

<CIT> discloses a display apparatus, and a structure of a light guide plate (LGP) of the display apparatus for providing a two-dimensional (2D) image and a three-dimensional (3D) image.

It is the object of the present invention to provide an improved light guide plate.

The above and/or other aspects will be more apparent by describing certain exemplary embodiments with reference to the accompanying drawings, in which:.

Specific structural or functional descriptions of exemplary embodiments provided in the present disclosure are exemplary to merely describe the examples. The exemplary embodiments may be modified and implemented in various forms, and the scope of the examples is not limited to the descriptions provided in the present specification.

However the invention is limited to the scope defined in the claims. If accidentally any term such as "for example", "may", "can", "exemplary", "optionally", "preferably" and the like, precedes a feature of the independent claims <NUM> and <NUM> in the description below, it should be understood that the claimed feature is in no way optional.

For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element.

It will be understood that when an element is referred to as being "connected," or "coupled," to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected," or "directly coupled," to another element, there are no intervening elements present.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly-used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Examples to be provided below may be used to display a two-dimensional (2D) image or a three-dimensional (3D) image in a display device. Examples may be implemented in various products, for example, a personal computer (PC), a laptop computer, a tablet computer, a smartphone, a television (TV), a smart home appliance, an intelligent vehicle, a wearable device, and a digital information display (DID).

Hereinafter, reference will now be made in detail to examples with reference to the accompanying drawings, wherein like reference numerals refer to like elements throughout.

<FIG> illustrates a display device according to an exemplary embodiment. Referring to <FIG>, a display device <NUM> includes a light source <NUM>, a display panel <NUM>, a light guide plate <NUM>, and a reflector <NUM>. <FIG> illustrates a cross section of the display device <NUM>. As will be described in detail below, the display device <NUM> may provide a 2D image and a 3D image. According to an exemplary embodiment, a noise caused by realizing the 2D image and the 3D image in a single device may be controlled, because structures for the 2D image and structures for the 3D image do not affect each other in the display device <NUM>,. For instance, a sufficient amount of light may be uniformly provided to the 2D image because the structures for the 3D image do not affect light for the 2D image when the light for the 2D image is provided. Also, directional light needed for the 3D image may be provided, because the structures for the 2D image do not affect light for the 3D image when the light for the 3D image is provided. In addition, in the display device <NUM>, an upper surface of a first output pattern <NUM> is fixed to the display panel <NUM> such that a relative position between a pixel of the display panel <NUM> and a direction of beam output from a backlight may be uniformly maintained relative to an entire area of the display panel <NUM>. Thus, quality deterioration of the 3D image may be controlled. Accordingly, the display device <NUM> may provide the 2D image and the 3D image with relatively high quality.

The display panel <NUM> may output the 2D image or the 3D image. According to an exemplary embodiment, the display panel may include a processor (computer processing unit) or a controller that controls the display panel to output the 2D image or the 3D image. The 2D image may require an entirely uniform backlight that represents an identical image within a range of a viewing angle. The backlight may be implemented by nondirectional light. A 3D display may be implemented by representing images of different viewpoints on each of a left eye and a right eye of a viewer. A 3D display of a glassless type may represent a 3D image by spatially dividing the 3D image based on a viewpoint. Thus, the 3D image may include the images of different viewpoints and require directional light. In an example, for the 2D image, the nondirectional light may be provided to the display panel <NUM> through the light source <NUM>, a second output pattern <NUM> of the light guide plate <NUM>, and the reflector <NUM>. For the 3D image, the directional light may be provided to the display panel <NUM> through the light source <NUM> and the first output pattern <NUM> of the light guide plate <NUM>.

The light source <NUM> provides light to the light guide plate <NUM>. According to an exemplary embodiment, the processor (computer processing unit) or the controller may control the light source <NUM> to output light for a 2D display mode or the 3D display mode. The light source <NUM> may provide light in different directions for each of the 2D image and the 3D image. For example, in response to the 3D image being output to the display panel <NUM>, the light source <NUM> provides light in a first direction to the light guide plate <NUM>. In response to the 2D image being output to the display panel <NUM>, the light source <NUM> provides light in a second direction to the light guide plate <NUM>. The light guide plate <NUM> may guide light incident from the light source <NUM> in the light guide plate <NUM> based on a total internal reflection condition.

The light guide plate <NUM> includes the first output pattern <NUM> on an upper surface of the light guide plate <NUM> and the second output pattern <NUM> on a lower surface of the light guide plate <NUM>. Light provided from the light source <NUM> to the light guide plate <NUM> may be totally reflected internally along the light guide plate <NUM> in response to the total internal reflection (TIR) condition being satisfied. The light provided from the light source <NUM> to the light guide plate <NUM> may be output to an outside of the light guide plate <NUM> and provided to the display panel <NUM> in response to the total internal reflection condition being not satisfied due to the first output pattern <NUM> or the second output pattern <NUM>.

Each of the first output pattern <NUM> and the second output pattern <NUM> may have a structure that reacts only with light provided in a predetermined direction. For example, the first output pattern <NUM> has a structure that reacts only with the light provided in the first direction, and the second output pattern <NUM> has a structure that reacts only with the light provided in the second direction. In an example, the first output pattern <NUM> reacts only with the light provided in the first direction through a structure in which the first output pattern <NUM> is perpendicular to the first direction and parallel to the second direction. The second output pattern <NUM> reacts only with light provided in the second direction through a structure in which the second output pattern <NUM> is perpendicular to the second direction and parallel to the first direction. However, it is not necessary that an output pattern, for example, a first output pattern or a second output pattern, be always perpendicular to an output direction, for example, a first direction or a second direction.

The first output pattern <NUM> may provide the directional light to the display panel <NUM> for the 3D image, and the second output pattern <NUM> may provide the uniform nondirectional light to the display panel <NUM> for the 2D image. The first output pattern <NUM> may provide the directional light through a structure that allows the total internal reflection condition to be broken in response to a predetermined directivity condition being satisfied. As will be described in detail below, the directional light may be provided by an inverted trapezoid shaped pattern of the first output pattern <NUM>. The second output pattern <NUM> may provide uniform light through a structure that allows the total internal reflection condition to be uniformly broken in various directions. The second output pattern <NUM> may output the light of which the total internal reflection is broken to the lower surface of the light guide plate <NUM>. The reflector <NUM> may reflect the light output through the second output pattern <NUM> to the display panel <NUM>. The reflector <NUM> may increase uniformity of the light provided to the 2D image by uniformly reflecting the light in various directions when reflecting the light.

<FIG> illustrates light sources and output patterns according to an example embodiment. Referring to <FIG>, a first light source <NUM> and a second light source <NUM> provide lights to a light guide plate in a first direction D1 and a second direction D2, respectively. The light sources <NUM> and <NUM> include various light sources, for example, light emitting diode (LED) light sources or laser diode (LD) light sources. To provide uniform light to the light guide plate, an additional light source or a reflector may be disposed on a side opposite the light sources <NUM> and <NUM>. The light guide plate includes a first output pattern <NUM> and a second output pattern <NUM>. Each of the first output pattern <NUM> and the second output pattern <NUM> may include a plurality of linear patterns. The linear patterns of the first output pattern <NUM> may be perpendicularly disposed to the first direction D1 and parallel to the second direction D2. The linear patterns of the second output pattern <NUM> may be perpendicularly disposed to the second direction D2 and parallel to the first direction D1. Thus, light provided in the first direction D1 is affected only by the first output pattern <NUM> and light provided in the second direction D2 is affected only by the second output pattern <NUM>. However, it is unnecessary that the linear patterns of the first output pattern <NUM> be perpendicularly disposed to the first direction D1. According to exemplary embodiment, to effectively utilize pixels of a display panel in both a horizontal direction and a vertical direction when a three-dimensional (3D) image is realized, the linear patterns of the first output pattern <NUM> may be slanted at a predetermined angle. Even though the linear patterns of the first output pattern <NUM> are slanted at the predetermined angle, uniform nondirectional light for a two-dimensional (2D) image may be easily provided in response to a total internal reflection condition being not broken when the light provided in the second direction D2 is guided by the light guide plate.

In response to the 3D image being displayed on the display panel, the first light source <NUM> may provide the light in the first direction D1 to the light guide plate. The light provided from the first light source <NUM> may be totally reflected internally in the light guide plate and then output to the display panel through the first output pattern <NUM>. In response to the 2D image being displayed on the display panel, the second light source <NUM> may provide the light in the second direction D2 to the light guide plate. The light provided from the second light source <NUM> may be totally reflected internally in the light guide plate and then output to the display panel through the second output pattern <NUM>. The first output pattern <NUM> and the second output pattern <NUM> may provide directional light or nondirectional light to the display panel based on respective structures and forms. For example, a display device provides the 3D image for a viewer by providing the directional light to the display panel configured to output the 3D image through the first light source <NUM>. Also, the display device provides the 2D image for the viewer by providing the nondirectional light to the display panel configured to output the 2D image through the second light source <NUM>. Thus, the display device may easily convert the 2D image and the 3D image.

<FIG> illustrates a structure of a cross section of a first output pattern according to an exemplary embodiment. Referring to <FIG>, a display device <NUM> includes a light guide plate <NUM>, diffusers <NUM>, <NUM>, and <NUM>, a reflector <NUM>, a display panel <NUM>, and first light sources <NUM> and <NUM>. The light guide plate <NUM> includes a first output pattern <NUM> and a second output pattern <NUM>. <FIG> illustrates a cross section of the display device <NUM> viewed from a second direction D2. A second light source configured to provide light in the second direction D2 is omitted in <FIG>. Arrows passing through a light guide bar (LGB) <NUM>, the diffuser <NUM>, the light guide plate <NUM>, and the display panel <NUM> indicate paths through which the light provided from the first light source <NUM> travels.

The first light sources <NUM> and <NUM> provide light in the first direction D1 to the light guide plate <NUM>. In response to a total internal reflection condition of light provided from the first light sources <NUM> and <NUM> being satisfied, the light provided from the first light sources <NUM> and <NUM> may be totally reflected internally in the light guide plate <NUM>. Conversely, in response to the total internal reflection condition of the light provided from the first light sources <NUM> and <NUM> being broken, the light provided from the first light sources <NUM> and <NUM> may be output to an outside of the light guide plate <NUM>. The first output pattern <NUM> may include a plurality of linear structures. The plurality of linear structures may have an inverse trapezoid shaped cross section <NUM>. In another embodiment, the first output pattern <NUM> may include a plurality of linear protrusions. The plurality of linear protrusions may have an inverse trapezoid shaped cross section. The first output pattern <NUM> may break the total internal reflection condition of the light provided from the first light sources <NUM> and <NUM> through the inverse trapezoid shaped cross section <NUM>. Thus, the light provided from the first light sources <NUM> and <NUM> may be output to the display panel <NUM> through the inverted trapezoidal cross section <NUM>.

The plurality of linear structures having the inverse trapezoid shaped cross section <NUM> may each be disposed at a predetermined interval to form the first output pattern <NUM>. The light provided from the first light sources <NUM> and <NUM> may have directivity at an angle formed by the reverse trapezoid shaped cross section <NUM> and may be output to the display panel <NUM>. Thus, the first output pattern <NUM> may provide directional light. By adjusting the angle formed by the reverse trapezoid shaped cross section <NUM>, a distribution of output light may be adjusted such that a viewing angle of a three-dimensional (3D) image may be adjusted.

As described above with reference to <FIG>, the linear structures of the first output pattern <NUM> and the linear patterns of the second output pattern <NUM> may be perpendicularly disposed to each other or disposed at an angle close to perpendicular. Because <FIG> illustrates the cross section of the display device <NUM> viewed from the second direction D2, the second output pattern <NUM> is represented as a straight line. Due to a feature of straightness of light, the second output pattern <NUM> does not substantially affect the light provided from the first light sources <NUM> and <NUM> and the total internal reflection condition of the light provided from the first light sources <NUM> and <NUM> may not be broken by the second output pattern <NUM>. Thus, the light provided from the first light sources <NUM> and <NUM> may not be output to the outside of the light guide plate <NUM> by the second output pattern <NUM>.

As will be described in detail below in <FIG>, the second output pattern <NUM> may be indented or protrude. A position at which the light provided from the first light sources <NUM> and <NUM> is totally reflected internally may be different based on a form of the second output pattern <NUM>, but the light provided from the first light sources <NUM> and <NUM> may be totally reflected internally without being output to the outside of the light guide plate <NUM> by the second output pattern <NUM>. The diffuser <NUM> and the reflector <NUM> may diffuse and reflect light output to the outside of the light guide plate <NUM> by the second output pattern <NUM>. Because the light provided from the first light sources <NUM> and <NUM> is not output to the outside of the light guide plate <NUM> by the second output pattern <NUM>, the diffuser <NUM> and the reflector <NUM> may not affect the light provided from the first light sources <NUM> and <NUM>. As will be described in detail below, light of a second light source may be provided to the diffuser <NUM> and the reflector <NUM>.

The LGB <NUM>, an LGB <NUM>, and the diffusers <NUM> and <NUM> may allow the light provided from the first light sources <NUM> and <NUM> to be uniformly diffused and incident on the light guide plate <NUM>. The diffusers <NUM> and <NUM> may be attached to the LGBs <NUM> and <NUM> in a direction of the light guide plate <NUM>, respectively. The LGBs <NUM> and <NUM> and the diffusers <NUM> and <NUM> may uniformly provide light to inverse trapezoid shaped cross sections each disposed at a predetermined interval by varying vertical and horizontal angles of the light provided in the first direction D1. Also, the LGBs <NUM> and <NUM> and the diffusers <NUM> and <NUM> may allow the light to be uniformly diffused in a right direction and a left direction and to be incident on the light guide plate <NUM>. Thus, brightness of images corresponding to various viewpoints may be uniform and brightness of pixels in an image corresponding to one viewpoint may also be uniform.

According to an exemplary embodiment illustrated in <FIG>, the first light sources <NUM> and <NUM> and the LGBs <NUM> and <NUM> are disposed on both side surfaces of the light guide plate <NUM>. This arrangement of the first light sources <NUM> and <NUM> and the LGBs <NUM> and <NUM>, however, is exemplary. The first light sources <NUM> and <NUM> and the LGBs <NUM> and <NUM> may be variously disposed based on different methods. For example, according to another exemplary embodiment, the first light source <NUM> and the LGB <NUM> may be disposed on a first side surface of the light guide plate <NUM> and the reflector <NUM> may be disposed on a second side surface the light guide plate <NUM>, which is opposite to the first side. The reflector <NUM> may provide light to a side surface on which the first light source <NUM> is not disposed by reflecting the light provided from the first light source <NUM>. The reflector may be disposed to reflect the light in various directions. In particular, the reflector <NUM> may have a surface in a triangle form in order to allow light reflected by the reflector <NUM> to be incident on another surface of the light guide plate <NUM> at a perpendicular incident angle similar to a perpendicular incident angle of light incident on one surface of the light guide plate <NUM> from the first light source <NUM>.

An upper surface of the first output pattern <NUM> may be fixed to the display panel <NUM> using an optical adhesive <NUM> such that a predetermined interval between the first output pattern <NUM> and the display panel <NUM> is maintained. For the total internal reflection condition, the light guide plate <NUM> may be surrounded by a medium having a density lower than a density of the light guide plate <NUM>. For example, in general, an air layer may be formed outside the light guide plate <NUM>. To maintain the air layer between the light guide plate <NUM> and the display panel <NUM>, the light guide plate <NUM> may not be attached to an entire surface of the display panel <NUM>. As such, the light guide plate <NUM> may be mechanically fixed to the display panel <NUM>. According to an exemplary embodiment, it may be desirable to provide directional light having an accurate angle to the display panel <NUM> in order to prevent quality deterioration of the 3D image. That is, it may be desirable to accurately fix the light guide plate <NUM> and the display panel <NUM> and maintain a state in which the light guide plate <NUM> and the display panel <NUM> are fixed. According to an exemplary embodiment of the first output pattern <NUM>, the air layer may be formed between the inverse trapezoid shaped cross sections, and a plane may be formed on the upper surface of the first output pattern <NUM>. Thus, the upper surface of the first output pattern <NUM> is fixed to the entire surface of the display panel <NUM> using the optical adhesive <NUM> such that an interval between the light guide plate <NUM> and the display panel <NUM> may be maintained. As will be described in detail below, the first output pattern <NUM> may be manufactured in a form of a film and easily bonded to the display panel <NUM> using the optical adhesive <NUM>.

<FIG> illustrates a light output formed by a first output pattern according to an exemplary embodiment. Referring to <FIG>, a light guide plate <NUM> includes a first output pattern <NUM> on an upper surface of the light guide plate <NUM> and a second output pattern <NUM> on a lower surface of the light guide pattern <NUM>. For ease of description, <FIG> illustrates that the first output pattern <NUM> has a reverse trapezoid shaped cross section. In response to light provided in a first direction D1 reaching the first output pattern <NUM>, a total internal reflection condition of the light provided in the first direction D1 may be broken. The light having the total internal reflection condition broken may be output to an outside of the light guide plate <NUM> through the reverse trapezoid shaped cross section. Because the reverse trapezoid shaped cross section has a predetermined angle, directional light for a three-dimensional (3D) image may be formed through the inverse trapezoid shaped cross section.

According to an exemplary embodiment, a feature of the directional light may be adjusted through a form of the inverse trapezoid shaped cross section. The inverse trapezoid shaped cross section of the first output pattern <NUM> includes a base line having a width W1, an upper base having a width W2, and two slanted side lines. The slanted side lines of the inverse trapezoid shaped cross section and the light guide plate <NUM> form an angle θ. An amount of the directional light output through the first output pattern <NUM> may be adjusted by adjusting the width W1. For example, when the width W1 increases, the amount of the directional light provided to the 3D image may increase and the 3D image may be relatively bright. However, when the width W1 is adjusted, uniformity of the 3D image is affected by the width W1 such that the width W1 is generally designed to be an optimal value. In addition, a distribution of the directional light output through the first output pattern <NUM> may be adjusted by adjusting the width W2 and a viewing angle of the 3D image may be adjusted by adjusting the distribution of the directional light.

<FIG> illustrates an arrangement of a first output pattern and light sources according to an exemplary embodiment. Referring to <FIG>, a first light source <NUM> is disposed on each of a left side and a right side of a light guide plate <NUM>, and a second light source <NUM> is disposed on another side of the light guide plate <NUM> that is adjacent to the left side and the right side of the light guide plate <NUM>. The arrangement of the first light source <NUM> and the second light source <NUM> of <FIG> is merely exemplary, and therefore the first light source <NUM> and the second light source <NUM> may be arranged in various manners. For instance, the first light source <NUM> and the second light source <NUM> may be disposed on different side surfaces of the light guide plate <NUM> that do not face each other. Also, each of the first light source <NUM> and/or the second light source <NUM> may be disposed on different side surfaces of the light guide plate <NUM> that face each other. For example, unlike <FIG>, the second light source <NUM> is disposed both below and above the light guide plate <NUM>. In addition, in response to the first light source <NUM> and the second light source <NUM> being disposed on only one side of the light guide plate <NUM>, a reflector may be disposed on the other side of the light guide plate <NUM>. For example, the reflector may be disposed below the light guide plate <NUM> which is opposite to the second light source <NUM>. A light guide bar (LGB) <NUM> may be disposed between the light guide plate <NUM> and each of the first light source <NUM> and the second light source <NUM>.

According to an exemplary embodiment, <FIG> illustrates a plane of the light guide plate <NUM> having the first output pattern disposed on an upper surface of the light guide plate <NUM>. The first output pattern may include a plurality of linear structures. The linear patterns may have the above-described inverse trapezoid shaped cross section.

In an example, the first output pattern may form a second direction D2 and an angle θ. Here, the angle θ indicates a slanted angle. As the first output pattern forms the slanted angle, a resolution degradation phenomenon occurring in a single direction, for example, a horizontal direction or a vertical direction, in a glassless type 3D display may be distributed in the horizontal direction and the vertical direction. In addition, a black stripe phenomenon occurring in the glassless type 3D display may be removed. Thus, quality of the 3D image may be enhanced and a number of viewpoints included in the 3D image may be increased.

The slanted angle may be determined based on a method identical to a method of determining an angle of a slanted lenticular lens in the glassless type 3D display technology. That is, the first output pattern may be formed based on a 3D display technology applied to a display panel. For example, the angle θ is determined based on a number of viewpoints of the 3D image displayed on the display panel, a resolution of the display panel, a pitch of the first output pattern, and/or a correlation between a pixel pattern of the display panel and the first output pattern.

According to an exemplary embodiment, in order to prevent possible deterioration of the quality of the uniformity of nondirectional light for the 2D image due to the slanted angle of the first output pattern, a range of the slanted angle may be limited such that a degree of quality deterioration of the light for the 2D image is within a predetermined threshold.

For example, the slanted angle may have a value greater than <NUM>° and less than <NUM>° based on a quality, for example, an image quality or a number of viewpoints, of the light for the 3D image and the quality, for example, a uniformity of nondirectional light, of the light for the 2D image. In this example, the first output pattern and a second output pattern may form an angle greater than <NUM>° and less than <NUM>°. In more detail, the angle θ may be <NUM>°, and the first output pattern and the second output pattern may form an angle of <NUM>°.

The above-described numerical values are merely exemplary, and therefore, the above-described numerical values may be variously changed based on a first constraint associated with the quality of the light for the 3D image and a second constraint associated with the quality of the light for the 2D image. For example, the first constraint includes a threshold angle or an angle range for increasing the quality of the light for the 3D image to be greater than or equal to a first threshold quality, and the second constraint includes a threshold angle or an angle range for preventing the quality of the light for the 2D image from being reduced to be less than or equal to a second threshold quality.

<FIG> illustrates the arrangement in which the first light source <NUM> provides light in the first direction D1 regardless of the angle θ. In <FIG>, a sufficient amount of light may also effectively reach the reverse trapezoid shaped cross section of the first output pattern. Even though the first output pattern is slanted at a predetermined angle, a form of the cross section of the first output pattern may be substantially the same as the reverse trapezoid shaped cross sections illustrated in <FIG> and therefore effects of the cross sections may be substantially the same. According to an example of <FIG>, there may be partial interference caused by the first output pattern in a 2D mode for the 2D image. However, the 2D mode is a mode that diffuses light incident on the light guide plate <NUM> as the nondirectional light such that the partial interference caused by the first output pattern may be substantially ignored because a portion of the directional light occurring due to the partial interference is covered by nondirectional lights.

<FIG> illustrates a structure of a cross section of a second output pattern according to an exemplary embodiment. Referring to <FIG>, a display device <NUM> includes a light guide plate <NUM>, a diffuser <NUM>, a reflector <NUM>, a display panel <NUM>, and a second light source <NUM>. The light guide plate <NUM> includes a first output pattern <NUM> and a second output pattern <NUM>. <FIG> illustrates a cross section of the display device <NUM> viewed from a first direction D1. In <FIG>, a first light source configured to provide light in the first direction D1 is omitted and a reverse trapezoid shaped cross section of the first output pattern <NUM> is not shown. Arrows passing through a light guide bar (LGB) <NUM>, a diffuser <NUM>, the light guide plate <NUM>, and the display panel <NUM> indicate paths through which light provided from the second light source <NUM> travels.

The second light source <NUM> provides light in a second direction D2 to the light guide plate <NUM>. In response to a total internal reflection condition of the light provided from the second light source <NUM> being satisfied, the light provided from the second light source <NUM> may be totally reflected internally in the light guide plate <NUM>. In response to the total internal reflection condition of the light provided from the second light source <NUM> being broken, the light provided from the second light source <NUM> may be output to an outside of the light guide plate <NUM>. A semi-circle shaped cross section <NUM> is merely exemplary, and therefore, the second output pattern <NUM> may have a circle shaped cross section, partially circular shaped cross section or a polygon shaped cross section. The second output pattern <NUM> may protrude from the light guide plate <NUM> or may be indented into the light guide plate <NUM>. The second output pattern <NUM> may break the total internal reflection condition of the light provided from the second light source <NUM> through the semi-circle shaped cross section <NUM>. Thus, the light provided from the second light source <NUM> may be output to a lower portion of the light guide plate <NUM> through the semi-circle shaped cross section <NUM>, and reflected by the reflector <NUM> to be provided to the display panel <NUM>.

Circle or partially-circular shaped cross sections, for example, the semi-circle shaped cross section <NUM>, may be disposed at various intervals in the second output pattern, and the second output pattern <NUM> may provide light at various intervals to the diffuser <NUM>. The diffuser <NUM> may diffuse the light provided from the second output pattern <NUM>. The diffuser <NUM> may provide light in various directions to the reflector <NUM> by varying horizontal and vertical angles of the light provided from the second output pattern <NUM>. The reflector <NUM> may reflect light provided from the diffuser <NUM> to the display panel <NUM>. The reflector <NUM> may have an upper surface in a triangle form in order to increase a front surface luminance by adjusting a viewing angle of a two-dimensional (2D) image. The reflector <NUM> may allow lights that are widely diffused by the diffuser <NUM> to be concentrated at a center portion of the display panel <NUM> through the triangle form. An angle of light provided to the display panel <NUM> may be adjusted based on a gradient of a triangle form positioned at an upper surface of the reflector <NUM> such that the viewing angle of the 2D image may be adjusted. The light provided from the second light source <NUM> may be reflected by the reflector <NUM> and then partially refracted through the diffuser <NUM>, the light guide plate <NUM>, and an optical adhesive <NUM> to be provided to the display panel <NUM>. The light provided from the second light source <NUM> may become nondirectional light by passing through the semi-circle shaped cross section <NUM> of the second output pattern <NUM>, the diffuser <NUM>, and the reflector <NUM> and then may be provided to the display panel <NUM>. Thus, a 2D image having uniform brightness may be provided through the display panel <NUM>.

The second light source <NUM> may provide the light in the second direction D2 to the light guide plate <NUM> through the LGB <NUM>. The LGB <NUM> and the diffuser <NUM> may allow the light provided from the second light source <NUM> to be uniformly diffused such that the light provided from the second light source <NUM> is incident on the light guide plate <NUM>. The diffuser <NUM> may be attached to the LGB <NUM> in a direction of the light guide plate <NUM>. The LGB <NUM> and the diffuser <NUM> may uniformly diffuse light to circle shaped cross sections by varying horizontal and vertical angles of the light provided in the second direction D2. Also, the LGB <NUM> and the diffuser <NUM> may allow the light to be uniformly diffused in a right direction and a left direction to be incident on the light guide plate <NUM>. In <FIG>, the second light source <NUM> and the LGB <NUM> are disposed on a left side surface of the light guide plate <NUM> and a reflector <NUM> is disposed on a right side surface of the light guide plate <NUM>. The arrangement of the second light source <NUM>, the LGB <NUM>, and the reflector <NUM> illustrated in <FIG> is only an example. The second light source <NUM> and the LGB <NUM> may be disposed on the right side surface of the light guide plate <NUM> instead of the reflector <NUM>. The reflector <NUM> may provide light to a side surface on which the second light source <NUM> is not disposed by reflecting the light provided from the second light source <NUM>. The reflector <NUM> may be disposed to reflect the light in various directions. In particular, the reflector <NUM> may have a surface in a triangle form in order to allow light reflected by the reflector <NUM> to be incident on the other surface of the light guide plate <NUM> at a vertical incident angle similar to a vertical incident angle of light incident on one surface of the light guide plate <NUM> from the second light source <NUM>. The reflector <NUM> may provide the light to the light guide plate <NUM> in a way similar to the light is provided through the second light source <NUM> and the LGB <NUM> through the surface of the triangle form.

As described above, the first output pattern <NUM> and the second output pattern <NUM> may be vertically disposed to each other or disposed at an angle between <NUM>° and <NUM>° which is close to vertical. Because <FIG> illustrates the cross section of the display device <NUM> viewed from the first direction D1, the output pattern <NUM> is represented as a straight line. Even though the total internal reflection condition of the light provided from the second light source <NUM> through the first output pattern <NUM> is broken or satisfied, the light provided from the second light source <NUM> is covered by nondirectional lights. Thus, the first output pattern <NUM> may not substantially affect the light provided from the second light source <NUM>.

<FIG> illustrates a light output formed by a second output pattern according to an exemplary embodiment. Referring to <FIG>, a light guide plate <NUM> includes a first output pattern <NUM> at an upper surface of the light guide plate <NUM> and a second output pattern <NUM> at a lower surface of the light guide plate <NUM>. In response to light provided in a second direction D2 reaching the second output pattern <NUM>, a total internal reflection condition of the light provided in the second direction D2 may be broken. The light of which the total internal reflection condition is broken may be output to an outside of the light guide plate <NUM> through a circle shaped cross section or a partially circular shaped cross section of the second output pattern <NUM> and provided to a reflector <NUM> by passing through a diffuser <NUM>. The light passing through the diffuser <NUM> may be diffused and provided as nondirectional light in various directions. Because an angle of light reflected by the reflector <NUM> is different depending on a triangle form of the reflector <NUM>, a viewing angle of a two-dimensional (2D) image may be different. In addition, the viewing angle of the 2D image may be different based on a diffusion angle of the diffuser <NUM>.

According to an exemplary embodiment, the second output pattern <NUM> may be integrally produced at one time in a light guide plate forming process, when the light guide plate is formed. For example, the second output pattern <NUM> may be integrally produced using a mold provided in a shape of the second output pattern. According to another exemplary embodiment, the second output pattern <NUM> may be produced separately from the light guide plate <NUM>. That is, the second output pattern <NUM> may be produced in a film form, and may be bonded to the light guide plate <NUM>. The second output pattern <NUM> may also be formed by various other processes and techniques.

<FIG> illustrates an arrangement of a second output pattern and light sources according to an exemplary embodiment. Referring to <FIG>, a first light source <NUM> is disposed on each of a left side and a right side of a light guide plate <NUM>, and a second light source <NUM> is disposed above the light guide plate <NUM>. As described above, the arrangement of the first light source <NUM> and the second light source <NUM> illustrated in <FIG> is merely exemplary. The first light source <NUM> and the second light source <NUM> may be disposed in different forms. <FIG> illustrates a plane of the light guide plate <NUM> according to an exemplary embodiment. <FIG> illustrates that a second output pattern may be disposed on a lower surface of the light guide plate <NUM>. The second output pattern may include a plurality of linear structures. The plurality of linear structures may have a circle shaped cross section, partially circular shaped cross section or a polygon shaped cross section. The linear structures may protrude from the light guide plate <NUM> or may be indented into the light guide plate <NUM>. A light guide bar (LGB) <NUM> may be disposed between the light guide plate <NUM> and each of the first light source <NUM> and the second light source <NUM>.

<FIG> each illustrate a structure of a plane of a second output pattern according to a respective exemplary embodiment. When a second output pattern includes a regular pattern, a brightness of a two-dimensional (2D) image may not be uniform due to a gradually decreasing amount of light output while passing through a light guide plate. Thus, the second output pattern may include an irregular pattern. For example, referring to <FIG>, the second output pattern includes a plurality of linear structures having different widths. Also, the linear patterns may be disposed at different intervals. Referring to <FIG>, the second output pattern includes group patterns <NUM> and <NUM>. Each of the group patterns <NUM> and <NUM> includes a plurality of linear structures having an identical width and an identical interval. The group patterns <NUM> and <NUM> may include different numbers of linear structures having different widths, or include linear structures having different intervals. In addition, various irregular linear patterns may be applied to the second output pattern.

<FIG> each illustrate a second output pattern according to an exemplary embodiment. As described above, a plurality of linear structures included in a second output pattern may have a circle shaped cross section, partially circular shaped cross section or a polygon shaped cross section. Also, the linear structures may protrude from a light guide plate or may be indented into the light guide plate. According to an exemplary embodiment, <FIG> illustrates a form in which a linear pattern <NUM> having a plurality of linear structures that are indented into a light guide plate <NUM> and a form in which a linear pattern <NUM> having a plurality of semi-circle shaped cross section structures that protrude from a light guide plate <NUM>. <FIG> illustrates a prism form in which a linear pattern <NUM> having a plurality of triangle shaped cross section structures are indented into a light guide plate <NUM> and a prism form in which a linear pattern <NUM> having a plurality of triangle shaped cross section structures that protrude from a light guide plate <NUM>. <FIG> illustrates a bump form in which a linear pattern <NUM> having a plurality of bump shaped cross section structures that are indented into a light guide plate <NUM> and a bump form in which a linear pattern <NUM> having a plurality of bump shaped cross section structures that protrude from a light guide plate <NUM>.

<FIG> is a flowchart illustrating a method of manufacturing a backlight unit according to an exemplary embodiment. Referring to <FIG>, in operation <NUM>, a manufacturing apparatus forms a first output pattern for outputting directional light to a display panel using light provided from a first light source. In operation <NUM>, the manufacturing apparatus forms, at a lower surface of a light guide plate, a second output pattern for outputting nondirectional light to the display panel using light provided from a second light source. In operation <NUM>, the manufacturing apparatus attaches the first output pattern to an upper surface of the light guide plate. In an exemplary embodiment, the first output pattern is manufactured by bonding two films. Detailed description of an exemplary process of manufacturing the first output pattern will be described with reference to <FIG>.

<FIG> illustrates a process of manufacturing a first output pattern according to an exemplary embodiment. Referring to <FIG>, in a first stage (Stage <NUM>), a manufacturing apparatus presses a mold having a groove in a trapezoid form or a triangle form on a first film coated with resin. In a second stage (Stage <NUM>), the manufacturing apparatus cures the resin of the first film in a state in which the mold is pressed on the first film. In a third stage (Stage <NUM>), the manufacturing apparatus stops the pressing by the mold. In a fourth stage (Stage <NUM>) and a fifth stage (Stage <NUM>), the manufacturing apparatus allows a protrusion in a trapezoid form or a triangle form formed by curing the resin of the first film to be in contact with a second film coated with resin. In a sixth stage (Stage <NUM>), the resin of the second film is cured in a state in which the protrusion of the first film is in contact with the second film. In response to the resin of the second film being cured, the first film and the second film form a single film, and a first output pattern in a film form is formed. The first output pattern may be manufactured by various other processes. For example, the first output pattern is manufactured by a semiconductor process such as an etching process. In response to an output pattern being manufactured in a film form, the output pattern may be easily bonded to a light guide plate through optical bonding.

Claim 1:
A backlight unit comprising:
a first light source (<NUM>; <NUM>, <NUM>; <NUM>; <NUM>) configured to provide first light for a three-dimensional, 3D, display;
a second light source (<NUM>; <NUM>; <NUM>; <NUM>) configured to provide second light for a two-dimensional, 2D, display;
a light guide plate (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>) comprising:
a first output pattern (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) formed on an upper surface of the light guide plate (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>) and configured to output the first light to a display panel (<NUM>; <NUM>; <NUM>); and
a second output pattern (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) formed on a lower surface of the light guide plate (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>) and configured to output the second light to the lower surface of the light guide plate (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>), wherein the first light source and the second light source are disposed on different side surfaces of the light guide plate that do not face each other;
a reflector (<NUM>; <NUM>; <NUM>; <NUM>) configured to reflect light output to the lower surface of the light guide plate through the second output pattern to the display panel; and
a controller configured to control the light sources to output light for a 2D display mode or a 3D display mode.