KR20170084888A - Crystal backlight unit - Google Patents

Abstract

A transparent backlight unit having an optical sheet and a light guide plate is disclosed. The transparent backlight unit device to which the at least one LED light source of the present invention is applied includes a prism for arranging a symmetric prism pattern on one longitudinal side in a shape selected from an engraved and an embossed shape, A light guiding plate, and a prism pattern formed on the lower surface of the light guiding plate to vertically output light emitted from the light guiding plate, thereby maximizing the front light output efficiency and maximizing the total reflection principle of the light guiding plate and the optical sheet, It is possible to control the light emitted from the back surface, so that the reflective sheet can be removed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a transparent backlight unit having an optical sheet and a light guide plate,

The present invention relates to a transparent backlight unit. More particularly, the present invention relates to a transparent backlight unit, and more particularly, to a prism pattern having a positive prism pattern formed on an upper surface of a light guide plate to emit light incident from an LED, And a transparent backlight unit including an optical sheet and a light guide plate which are configured by an optical sheet for vertically emitting light so that an image of an object behind the light guide plate is clearly projected and displayed.

In general, a display device has a large display area, is light in weight to increase mobility, and requires a small size in order to increase portability.

The LCD display device has a tendency to replace all CRT display devices because of its excellent image quality, light weight, thinness, and low power consumption. Especially, the LCD display device is adopted in devices requiring mobility and portability such as notebook computers and mobile phones.

However, since the LCD display device is non-luminous, it can not display visual information itself, and an external light source must be separately provided. A backlight unit device has been developed which supplies a planar light source of uniform luminance according to such necessity.

The backlight unit includes a light source, a light guide plate, and a reflector, and is divided into an edge type and a direct type by a method of arranging a light source.

Since the edge type backlight unit device has a light source disposed on a side surface of the light guide plate, it has a relatively thin structure and is mainly used in devices requiring small size, light weight and thinness such as portable equipment.

The direct-type backlight device has a relatively thick thickness because the light source is disposed on the bottom surface of the light guide plate. However, since the light efficiency is excellent, the quality of the displayed information is enhanced. Therefore, it is mainly used in a device requiring a large screen such as a TV monitor.

Hereinafter, a light guide plate using an edge type backlight unit will be mainly described.

The light guide plate according to the related art is incident on the light of a point light source or a linear light source incident from a light source disposed on a side surface and scattered in the interior thereof to have a relatively small area area to be converted and emitted into a planar light source.

Particularly, since the brightness is uneven in the state of being converted into the surface light source, the difference in brightness occurs partially, and since the effective area is small, it is difficult to increase the width of the effective screen for displaying information, .

In order to increase the effective area of the planar light source, the light scattering should be performed well inside the main body, and in order that the scattering can be performed well, the total reflection and diffuse reflection It should be smoothly performed, and the luminance should not be unnecessarily attenuated in the light emission path.

In the prior art, polymethyl methacrylate acrylic resin (PMMA: Poly-Methyl Methacrylate) was used as a material of the light guide plate body, and a groove formed by V-shaped cutting was formed on the lower surface of the body so as to scatter light, A diffusion plate, a horizontal and a vertical prism plate, and the like were attached to the upper surface of the light guide plate main body in order to uniformly emit light to the planar light source.

However, in the conventional technique, there is a problem that the time and cost for V-shaped cutting are large and the occurrence of defects increases.

On the other hand, a manufacturing process for attaching a diffuser plate, a prism plate, and the like to the upper surface of the light guide plate main body is complicated, and the production time is prolonged, and the cost increases.

Further, there is a problem that it is difficult to widen the area of the planar light source that is attenuated and diffused in a continuous manner at the interface separating the materials such as the main body of the light guide plate, the diffuser plate, the prism plate, and the like.

Therefore, it is necessary to develop a technique for simplifying the manufacturing process of the edge type light guide plate, reducing the production time, and improving the quality of the displayed information without the difference in contrast.

Particularly, it is necessary to develop a technique for simplifying the entire configuration of the edge type light guide plate and preventing unnecessary attenuation of the brightness of the surface light source in the process of emitting light.

Meanwhile, in recent years, studies have been made actively on a transparent liquid crystal display device in which a user can view an object or an image located on the opposite side through a liquid crystal display device.

Such a transparent liquid crystal display device has advantages of space utilization, interior and design, and can have various application fields.

In particular, in a transparent liquid crystal display device, a transparent liquid crystal display device capable of clearly distinguishing objects or images located on the opposite side and capable of realizing an image realized from a liquid crystal display device more clearly is desired.

KR Patent Publication No. 10-2015-0126199 (Nov.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transparent backlight unit device having a light guide plate and an optical sheet capable of implementing a transparent display by removing a reflective sheet by applying a high efficiency light guide plate and an optical sheet.

It is another object of the present invention to provide a transparent backlight unit having a light guide plate and an optical sheet which can reduce the material cost of various product groups compared to conventional transparent displays.

The present invention also includes an optical sheet for vertically emitting light emitted from a light guide plate by forming a prism pattern having a positive angle on an upper surface of a light guide plate to emit light incident from an LED and another prism pattern formed on a lower surface And a transparent backlight unit having a light guide plate and an optical sheet.

Another object of the present invention is to provide a transparent backlight unit having a light guide plate and an optical sheet in which a symmetrical prism pattern is formed on a light guide plate and an asymmetric prism pattern is formed on an optical sheet.

In order to solve such a problem, a transparent backlight unit device to which one or more LED light sources of the present invention are applied has a symmetrical prism pattern arranged on one side of a long side in a shape selected from an engraved and an embossed shape, A prism light guide plate for emitting light to the other side, and an optical sheet formed by forming a prism pattern formed on the bottom surface of the light guide plate and vertically emitting light emitted from the light guide plate.

The prism pattern of the optical sheet is formed by a triangular shape (formed by vertexes A, B, and C) with a positive angle, and one side (BC side) contacts one side surface of the optical sheet, And the angle between the AB side and the AC side is such that an angle formed between the AB side and the AC side is such that an imaginary line is connected at the vertex A perpendicular to the BC side, It is preferable that the angle between the line and the AB side is larger than 60 DEG and the angle formed by the virtual line and the AC side is smaller than 80 DEG.

It is more preferable that the symmetrical pattern of the light guide plate is formed in a round positive embossing pattern and the ratio of the height H of the light pattern to the distance W is less than 1,

Therefore, according to the transparent backlight unit including the light guide plate and the optical sheet of the present invention, it is possible to maximize the front light exit efficiency and to control the back light by applying the total reflection principle of the light guide plate and the optical sheet, There is an effect that can be done.

And the light emitted by the LED light source is led to the front surface of the backlight unit, that is, the light is emitted perpendicularly, thereby improving the front exit light luminance.

1 is a schematic view of a transparent backlight unit having a light guide plate and an optical sheet according to an embodiment of the present invention.
Figs. 2 and 3 are cross-sectional views showing light exit paths of a light guide plate and an optical sheet of the present invention,
4 is an enlarged view of the prism pattern of the optical sheet of the present invention,
And,
5 is an enlarged view of the prism pattern of the light guide plate of the present invention.

It is to be understood that the words or words used in the present specification and claims are not to be construed in a conventional or dictionary sense and that the inventor can properly define the concept of a term in order to describe its invention in the best possible way And should be construed in light of the meanings and concepts consistent with the technical idea of the present invention.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise. Also, the terms " part, "" module, "" device, "unit and the like, which are described in the specification, mean a unit for processing at least one function or operation, Lt; / RTI >

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a transparent backlight unit having a prism light guide plate according to an embodiment of the present invention. Referring to FIG.

As shown, the light guide plate 130 of the present invention is interposed between the object 150 and the transparent TFT-LCD 110 so that the opposite object or image can be clearly seen, And to provide a high brightness light to the optical sheet 120 so as to include a symmetric prism pattern.

The optical sheet 120 forms a pattern having a specific angle on the upper surface of the light guide plate 130 so that the light emitted from the light guide plate 130 can vertically enter the transparent TFT-LCD 110.

For this purpose, the optical sheet 120 densely forms an optical prism pattern on the opposite side of the transparent TFT-LCD 110, that is, on the surface facing the light guide plate 130. For example, B, and C).

 Referring to the cross-sectional view showing the light exit path of the light guide plate and the optical sheet of the present invention shown in Figs. 2 and 3 and the enlarged view of the prism pattern of the optical sheet of the present invention shown in Fig. 4, the optical sheet 120 includes a transparent TFT- An optical top surface 123 for emitting light to the LCD 110 and an optical bottom surface 122 in which the optical prism pattern 121 is densely embossed.

The optical prism pattern 121 should be such that light incident thereon is reflected internally and emitted vertically onto the top surface 123 of the orophanic sheet 120.

To this end, the optical prism pattern is formed of a triangle, and the vertex A is disposed toward the light guide plate 130.

That is, one side (BC side) of the triangle is in contact with the lower surface 122 of the optical sheet 120, and two sides (AB side, AC side) are formed in a direction of the light guide plate 130, Are equal to or different from each other.

That is, the angle formed between the AB side and the AC side is perpendicular to the BC side, the virtual line is connected at the vertex A, the angle Aa formed between the virtual line and AB side is greater than 60 degrees, The angle Ab is set to be smaller than 80 °.

When the angle Aa between the imaginary line and the AB side is less than 60 degrees, the light emitted from the light guide plate 130 does not pass through the AB side and diffuses irregularly to decrease the brightness, resulting in poor luminous efficiency. In the case of the configuration in which the angle formed by the AC side Ab is larger than 80 degrees, there is a problem that the light passing through the side AB passes through without being reflected by the AC side, resulting in a problem that the luminance can not be uniformly formed.

In addition, a prism pattern must be formed densely for uniform brightness.

Referring to the drawing, it can be seen that the optical prism pattern 121 is formed continuously and densely on the lower surface 122 of the optical sheet 120.

The optical sheet 120 is made of transparent plastic or glass having a transmittance of 80% or more and a refractive index of 1.3 to 1.8 so that the light incident on the prism pattern 121 is uniformly diffused and emitted.

For example, transparent PMMA (PolymethylMethacrylate) having a refractive index of 1.49 and transparent PET (Polyethylene terephthalate) having a refractive index of 1.64 can be used.

In the transparent TFT-LCD 110, a pixel region is defined by a plurality of gate lines and data lines crossing each other, a thin film transistor is provided at each intersection point, and one-to-one correspondence with transparent pixel electrodes formed in each pixel region, do.

Since the transparent TFT-LCD 110 has a general structure, a detailed description thereof will be omitted.

The light guide plate 130 is made of a transparent plastic or glass material having a transmittance of 80% or more and a refractive index of 1.3 to 1.8 so that the light incident on the prism patterns 131a, 131b and 131c is uniformly diffused and emitted.

For example, transparent PMMA (PolymethylMethacrylate) having a refractive index of 1.49 and transparent PET (Polyethylene terephthalate) having a refractive index of 1.64 can be used.

The light guide plate 130 is excellent in transparency, weatherability, and colorability, and guides the diffusion of light when light is transmitted. The light guide plate 130 is provided with an optical sheet 120 As shown in Fig.

That is, the light emitted by the LED light sources 140 provided in the light guide plate 130 is guided to the front surface of the transparent TFT-LCD 110 to be vertically emitted, thereby improving the front exit light luminance.

Specifically, light having passed through the prism patterns 131a, 131b and 131c formed on the upper surface 133 of the light guide plate 130 is incident on the AB side of the optical prism pattern 121 of the optical sheet 120, The light is totally reflected and emitted vertically so as to improve the front exit light luminance of the TFT-LCD 110. [

The light guide plate 120 may be formed by arranging the symmetrical prism patterns 131a, 131b and 131c on the upper surface 133 in the longitudinal direction of the light guide plate so as to guide light incident from the LED light source 130 into any one shape So that the light of the inserted LED light source 140 is emitted to the optical sheet 120.

The LED light source 140 may be provided on one side or both sides of the light guide plate 130 so as to face the light incident surface 132 of the light guide plate 130 to form an edge light guide plate and light emitted from the LED light source 140 may be incident The light incident on the light guide plate 130 spreads evenly over a wide area of the light guide plate 130 while traveling through the light guide plate 130 by total reflection several times and light passing through the prism patterns 131a, And then emitted to the optical sheet 120.

In order to improve luminous efficiency and brightness, the LED light source 140 uses a blue LED including a blue LED chip having excellent luminous efficiency and luminance, and uses a cerium-doped yttrium aluminum garnet (YAG: Ce) And a yellow phosphor.

The blue light emitted from the LED light source 140 is mixed with the yellow light emitted by the fluorescent material through the phosphor, thereby realizing the white light.

The light guide plate 130 includes symmetrical prism patterns 131a, 131b and 131c on one side in order to supply a uniform planar light source. The prism patterns 131a, 131b and 131c are arranged in the light guide plate 130 And serves to guide light.

The light incident on the prism patterns 131a, 131b, and 131c should be uniformly diffused and emitted to the orphanage sheet 120. [

That is, the light incident from the LED light source 140 into the light guide plate 130 is guided by the prism patterns 131a, 131b, and 131c formed on the upper surface 133 of the light guide plate 130, And the light emitted from the optical sheet 120 generates a vertical surface light source toward the transparent TFT-LCD 110. The light emitted from the optical sheet 120 is incident on the transparent TFT-

The light guide plate 130 is disposed on the rear surface of the transparent TFT-LCD 110 and the optical sheet 120 to form a prism pattern It is possible to reduce the visibility of the transparent TFT-LCD 110 by allowing the surface light source to be formed by the optical prism pattern 121 of the optical sheet 120, .

Specifically, a prism pattern of a specific shape is formed on the upper surface 133 of the light guide plate 130. The light emitted from the LED light source 140 may be incident on the light guide plate 130 without any light loss, The patterns 131a, 131b and 131c formed on the upper surface 133 of the light guide plate 130 may be spaced apart from each other by a predetermined distance or formed to have a small size.

In particular, a prism pattern is formed on the upper surface 133 of the light guide plate 130 so that the light guide plate itself induces light diffusion to be emitted to the optical sheet 120, It is possible to see objects or images located on the opposite side of the transparent TFT-LCD 110 more clearly than in the case where they are not located on the back side of the TFT-LCD.

The prism patterns 131a, 131b and 131c are formed on the upper surface 133 of the light guide plate 130 so as to be spaced apart from each other or have a small size so that the light emitted from the LED light source 140 is guided to the light guide plate 130 Or light of a uniform luminance can be emitted to the optical sheet 120 through the light guide plate 130, thereby improving the light efficiency of the backlight unit.

As described above, the light efficiency of the backlight unit is improved by the prism patterns 131a, 131b, and 131c of the light guide plate 130 and the optical prism patterns 121 of the optical sheet 120, It is possible not only to realize an image at a high brightness but also to visually observe an object or an image located on the opposite side of the transparent TFT-LCD 110 when the image is not driven.

For this purpose, the prism patterns 131a, 131b, and 131c are formed in a round-shaped embossed pattern having a semicircular shape.

Referring to an enlarged view of the prism pattern of the light guide plate of the present invention shown in FIG. 5, a round pattern spaced by a predetermined distance from the upper face 133 of the light guide plate 130 is formed.

At this time, the ratio of the height (H) of the round pattern to the distance (W) should be less than one.

That is, when the height H is higher than the interval W, when the light incident from the LED light source 140 is incident into the prism patterns 131a, 131b, and 131c, total reflection occurs in the prism pattern, 120). ≪ / RTI >

Therefore, the ratio between the height H and the gap W is preferably 0.4 to 0.6.

That is, when the pattern interval is about two times larger than the height, the light is emitted uniformly to the optical sheet 120. [

The prism patterns 131a, 131b and 131c formed on the upper surface 133 of the light guide plate 130 can be densely formed and can be formed to have a small size, 140 are uniformly emitted to the optical sheet 120 without loss of light.

Hereinafter, referring to FIG. 2 and FIG. 3, the light guide of the light guide plate and the optical sheet according to the embodiment of the present invention will be schematically described.

The external light of the object 140 incident from the opposite side of the transparent TFT-LCD 110 is directly reflected by the light guide plate 130, the optical sheet 120, and the transparent TFT- By passing through the LCD 110, an object or an image located on the opposite side of the transparent TFT-LCD 110 can be seen.

In addition, when an image is implemented in the transparent TFT-LCD 110, an object or an image located on the opposite side of the transparent TFT-LCD 110 can be viewed. In this case, And the image is realized in the transparent TFT-LCD 110 through the light.

That is, the light emitted from the light guide plate 130 is provided to the optical sheet 120, the light vertically emitted from the optical sheet 120 is provided to the transparent TFT-LCD 110, and the transparent TFT- The image is realized through the difference in the transmittance of the light emitted from the light guide plate 120.

The lights a and b emitted from the LED light source 140 are guided to the inside of the light guide plate 130 through the light incoming surface 132 of the light guide plate 130. Here, And the light incident into the light guide plate 130 is totally reflected in the light guide plate 130 and is emitted by the prism patterns 131a, 131b and 131c formed on the upper surface 133, And is incident on any one of the optical prism patterns 121 formed on the surface.

The light incident on the optical prism pattern 121 is internally reflected and vertically emitted to the upper surface 123 of the optical sheet 120 vertically.

At this time, the light emitted toward the upper surface 123 of the optical sheet 120 passes through the upper surface 123 of the optical sheet 120 due to the refractive index difference of the optical sheet 120 and the air, In the vertical direction.

Referring to FIG. 3, it can be seen that a clear image is displayed even when the outgoing light (a, b) passes through the light guide plate and exits (a dotted line in the drawing).

As described above, according to the transparent backlight unit including the light guide plate and the optical sheet of the present invention, a round pattern having a symmetrical shape is formed on the upper surface of the light guide plate, an optical prism pattern is formed on the lower surface of the opposed optical sheet, It is possible to emit a surface light source of one brightness.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art.

110: TFT-LCD 120: Optical sheet
121: optical prism pattern 122: optical bottom surface
123: optical upper surface 130: light guide plate
131a, 131b, and 131c: prism patterns
132: incoming surface 133: upper surface
134: lower surface 140: LED light source
150: Things

Claims (6)

A transparent backlight unit device to which one or more LED light sources are applied,
A prism light guide plate for arranging a symmetrical prism pattern on one side in the longitudinal direction in a shape selected from an engraved and an embossed shape and emitting the light of the light source inserted in one end to the other side;
An optical sheet for forming a prism pattern formed on a bottom surface of the light guide plate and vertically emitting light emitted from the light guide plate;
And a transparent backlight unit device.
The method according to claim 1,
The prism pattern of the optical sheet
(BC side) is in contact with one side of the optical sheet, and the two sides (AB sides, AC sides) are formed in a direction of being embossed in the direction of the light guide plate Wherein the lengths of the AB sides and the AC sides are equal to or different from each other.
The method of claim 2,
The angle between the AB side and the AC side is
Wherein a virtual line is connected at a vertex A perpendicular to the BC side and an angle between the virtual line and the AB side is greater than 60 degrees and an angle between the virtual line and the AC side is less than 80 degrees.
The method according to claim 1,
The light guide plate and the optical sheet
Wherein the transparent backlight unit device has a transmittance of 80% or more and a refractive index of 1.3 to 1.8.
The method according to claim 1,
The symmetric pattern of the light guide plate
And a ratio of a height (H) and a clearance (W) of the launch pattern from the surface of the light guide plate is less than 1. The transparent backlight unit device according to claim 1,
The method of claim 5,
Wherein a ratio of a height (h) of the round pattern to an interval (w) is 0.4 to 0.6.

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